Zh Nevropatol Psikhiatr Im S S Korsakova. 1990;90(7):108-12.
Regional cerebral angiodystonia in the practice of a neuropathologist and therapist.
[Article in Russian]
Pokalev GM, Raspopina LA.
Altogether 108 patients with regional cerebral angiodystonia were
examined using rheoencephalography, measurements of temporal and venous
pressure and functional tests (nitroglycerin and bicycle ergometry).
Three variants of abnormalities connected with regional cerebral
angiodystonia were distinguished: dysfunction of the inflow, derangement
of the venous outflow, and initial functional venous hypertonia. The
patients were treated with nonmedicamentous therapy (electroanalgesia,
magnetotherapy, iontotherapy).
Extremely low frequency electromagnetic fields
stimulation modulates autoimmunity and immune responses: a possible
immuno-modulatory therapeutic effect in neurodegenerative diseases
Fabio Guerriero, M.D., Ph.D.1,2,* and Giovanni Ricevuti1,21Department of Internal Medicine and Medical Therapy, Section of Geriatrics, University of Pavia, Pavia, Italy
2Azienda di Servizi alla Persona, Istituto di Cura Santa Margherita of Pavia, Pavia, Italy
*Correspondence to: Fabio Guerriero, ti.aivapidatisrevinu@10oreirreug.oibaf.
Increasing evidence shows that
extremely low frequency electromagnetic fields (ELF-EMFs) stimulation is
able to exert a certain action on autoimmunity and immune cells. In the
past, the efficacy of pulsed ELF-EMFs in alleviating the symptoms and
the progression of multiple sclerosis has been supported through their
action on neurotransmission and on the autoimmune mechanisms responsible
for demyelination. Regarding the immune system, ELF-EMF exposure
contributes to a general activation of macrophages, resulting in changes
of autoimmunity and several immunological reactions, such as increased
reactive oxygen species-formation, enhanced phagocytic activity and
increased production of chemokines. Transcranial electromagnetic brain
stimulation is a non-invasive novel technique used recently to treat
different neurodegenerative disorders, in particular Alzheimer’s
disease. Despite its proven value, the mechanisms through which EMF
brain-stimulation exerts its beneficial action on neuronal function
remains unclear. Recent studies have shown that its beneficial effects
may be due to a neuroprotective effect on oxidative cell damage. On the
basis of in vitro and clinical studies on brain activity,
modulation by ELF-EMFs could possibly counteract the aberrant
pro-inflammatory responses present in neurodegenerative disorders
reducing their severity and their onset. The objective of this review is
to provide a systematic overview of the published literature on EMFs
and outline the most promising effects of ELF-EMFs in developing
treatments of neurodegenerative disorders. In this regard, we review
data supporting the role of ELF-EMF in generating immune-modulatory
responses, neuromodulation, and potential neuroprotective benefits.
Nonetheless, we reckon that the underlying mechanisms of interaction
between EMF and the immune system are still to be completely understood
and need further studies at a molecular level.Keywords: electromagnetic fields, Alzheimer’s disease, transcranial magnetic stimulation, autoimmunity, immunomodulation
Introduction
The etiology of neurodegenerative
diseases is multifactorial. Genetic polymorphisms, increasing age and
environmental cues are recognized to be primary risk factors. Although
different neuronal cell populations are affected across diverse
neurodegenerative disorders, hallmark protein modifications is a common
feature that supports the differential disease diagnosis and provides a
mechanistic basis to gauge disease progression (Bossy-Wetzel et al.,
2004).
It is becoming increasingly clear that, particularly for
chronic neurodegenerative disorders occurring late in life, a complex
combination of risk factors can initiate disease development and modify
proteins that have a physiological function into ones with pathological
roles via a number of defined mechanisms (Moreno-Gonzalez and Soto, 2011).
Amyloid-beta plaques and tau protein tangles – hallmarks of
the pathology – are most likely a non-specific result of the disease
process, rather than a cause (Lee et al., 2007). A large body of
evidence supports the direct contribution of inflammation in the
development and progression of neurodegeneration (Tweedie et al., 2007).
A common denominator in the occurrence of different pathogenic
mechanisms is oxidative stress accompanied by redox dysregulation, which
have a role in mitochondrial dysfunction, toxicity, missignalling by
calcium, glial cell dysfunction and neuroinflammation itself. Each of
these can influence one another at multiple different levels, and hence
oxidative stress can both be secondary to them as well as have a primary
part in their initiation (von Bernhardi and Eugenin, 2012).
In the last years, evidence are remarkably revealing that
Alzheimer’s disease (AD) has an autoimmune component (D’Andrea, 2005).
In older patients the presence of anti-neuronal autoantibodies in the
serum frequently occurs; if blood-brain barrier (BBB) dysfunction comes
up, these autoantibodies are able to reach their targets and determine
deleterious effect (D’Andrea, 2003). In fact, a profound change in BBB
permeability has been observed in AD. In these patients amyloid deposits
have been observed in microvessels and this overload is associated with
degenerating endothelium (decreased mitochondrial content, increased
pinocytotic vesicles), damaged smooth muscle cells and pericytes, and
basement membrane changes (focal necrosis, reduplication, increased
collagen content, disintegrating) (Thomas et al., 1996; Wardlaw et al.,
2003). All these components strengthen the possibility that the ‘major
pathological role of amyloid in AD may be to inflict vascular damage’
and hence, impair BBB function (Franzblau et al., 2013; Attems and
Jellinger, 2014).
Immunoglobulins (IGs) have been detected in serum,
cerebrospinal fluid and amyloid plaques of patients with AD. IGs are
associated with vessel-associated amyloid, which has been linked to a
faulty BBB (Franzblau et al., 2013). As a consequence, the presence of
neuronal autoantibodies associated with a BBB dysfunction seems to be a
relevant part of AD neuropathology (Attems and Jellinger, 2014).
Additional data about relationship between autoimmune diseases (e.g.,
thyroid dysfunction, diabetes) and AD has been proven. In fact,
patients with AD have a significant increase in the values of
anti-thyroglobulin and anti-microsomial autoantibodies compared to
healthy controls (Genovesi et al., 1996).
Moreover, typical features of autoimmunity have been associated with both AD and diabetes (e.g.,
high levels of advanced glycation end products and their receptor have
been detected in tissues and in the circulation in both disease)
(Mruthinti et al., 2006).
In summary, these data in the context of
the underlying mechanisms of many autoimmune diseases indicated that AD
has proven autoimmune mechanisms, which provide a link between vascular
pathology (altered BBB function) and neuronal cell death. Furthermore,
according to these data, BBB dysfunction precedes neuronal degeneration
and dementia (Rhodin and Thomas, 2001).
Electromagnetic Brain Stimulation and Immunomodulation in Neurodegenerative Diseases
Over the past decades, neuroscientists
and clinicians have been exploring the properties of the brain’s
electromagnetic activity for both diagnostic and therapeutic purposes.
In the 1990s, research on electromagnetic radiation was motivated by the
need to better understand the potential harmful effects of
environmental magnetic fields (Bennett, 1995; Bracken and Patterson,
1996); actually, it is becoming increasingly clear that interactions
between magnetic fields and biological systems deserve to be studied in
their own right because these interactions appear to be fundamental to
life processes and could represent a therapeutic agent in several
diseases.
In our opinion, one of the more striking observations
related to the effects of EMFs on biological systems concerns the
presence of a “window effect,” showing that biological effects occur
only at particular combinations of frequency and field intensity
(Panagopoulos and Margaritis, 2010). These effects have been reported
especially for changes in calcium ion flux in cells and tissues. Related
window effects are reports of signal-specific quantitative and
qualitative response to EMFs in several different tissues (Azanza and
del Moral, 1994).
ELF-EMFs interact readily with the central nervous system
(CNS). While the high-frequency EMFs encountered in industry can expose
workers to an increased risk of AD (Hakansson et al., 2003), amyotrophic
lateral sclerosis and multiple sclerosis (MS) (Johansen, 2004), EMFs of
weak and very weak intensity can exert interesting and proven
therapeutic effects on the CNS (Sandyk, 1992; Sandyk and Iacono, 1994;
Boggio et al., 2012). The level of radiation is typically in the range
of 1 millitesla (mT) in most studies.
Transcranial magnetic brain stimulation (TMS) is a
commonly-used neurostimulation and a neuromodulation technique, based on
the principle of electromagnetic induction of an electrical field in
the brain. This field can be of sufficient magnitude and density to
depolarize neurons, and when TMS pulses are applied repetitively they
can modulate cortical excitability, decreasing or increasing it,
depending on the parameters of stimulation, even beyond the duration of
the train of stimulation (Fregni and Pascual-Leone, 2007; Ridding and
Rothwell, 2007).
The last decade has seen a rapid increase in the
applications of TMS to study cognition, neurobehavioral relations and
the pathophysiology of several neurologic and psychiatric disorders.
Evidence has accumulated that demonstrates that TMS provides a valuable
tool for modulating brain activity in a specific, distributed,
cortico-subcortical network through control and manipulation of
cognition, neuromotoricity and behavior (George et al., 2007; Guerriero
et al., 2015).
Since the immune system plays a primary role in the
control of many diseases and tumor growth, many laboratories have
investigated the influence of ELF-EMF stimulation on blood mononuclear
cells, various cellular components and cellular processes; other studies
have examined electromagnetic effects on specific genes expressions and
signal transduction pathways, but the experimental data obtained are
currently controversial (Cossarizza et al., 1993; Onodera et al., 2003).
The mechanisms by which ELF-EMFs elicit cellular responses
are somewhat still unknown, and it is still unclear which cellular
components mediate these fields’ effects. However, there are several
hypotheses to explain EMF interaction with the living matter.
It is assumed that some type of initial interaction occurs
at the level of the cell membrane and that specific signal
amplification processes carry the membrane-mediated effect into the cell
(Frey, 1993). Molecular studies of the membrane signaling processes
have shown, for example, that the involved cells can use mechanisms such
as intracellular second-messenger (e.g., Ca2+,
cyclic adenosine monophosphate [cAMP], cyclic guanosine monophosphate
[cGMP]) cascades, positive feedback, and linear membrane channel-gating
(Grundler et al., 1992). Some of the most important calcium-related
processes such as synaptic neurotransmitter and synthesis and release
and levels of cAMP (Matthews and Gersdorff, 1996), essential for the
functioning of the neurons that are influenced by EMFs (Rosen, 1992). In
addition, amplification via calcium flux could also provide
the means by which the membrane-mediated effects of EMFs could be
carried into the cell (Karabakhtsian et al., 1994).
As described below, EMFs proved to exert a certain immune
function modulation. Modulation of neural activity by ELF-EMFs could
possibly counteract the aberrant pro-inflammatory responses present in
neurodegenerative and neuropsychiatric disorders reducing their severity
and, possibly, their onset.
Thus, in the next sections we will
address the influence of ELF-EMFs on autoimmunity and immune cells,
supposing that ELF-EMF may act on the basis of mechanisms centered on
immunomodulation. This could have particular relevance for the treatment
of neurodegenerative disorders, such as AD.
Low-frequency Electromagnetic Fields Stimulation and Autoimmunity
Regarding a possible relationship
between EMF and autoimmunity, the researches conducted by Sandyk and
colleagues deserve great interest. In the 1990s, Sandyk amply
demonstrated the efficacy of pulsed ELF-EMFs of a few mT in alleviating
the symptoms of MS through their action on axonal and synaptic
neurotransmission (Sandyk and Iacono, 1993; Sandyk and Dann, 1995).
Weekly treatment administered for years with very weak ELF-EMFs can
alter the clinical course of chronic progressive MS, arresting
progression of the disease for as long as four years (Sandyk, 1995a,
1997). This observation prompts the hypothesis that, in addition to
effects on axonal and synaptic neurotransmission, effects may also be
exerted on the autoimmune mechanisms responsible for demyelination.
Other proposals that to use pulsed ELF-EMFs of a few mT
aims to modify the autoimmune pathology of the disease by eliciting
profound membrane changes (Bistolfi, 2002) (the so-called Marinozzi
effect) (Marinozzi et al., 1982) in the MS plaque cells.
While the action of ELF fields of a few pT is
characterized by an improvement in neurotransmission, the use of ELF
fields of a few mT aims to exert an action of local immunomodulation on
the cells of the MS plaque through the induction of the Marinozzi
effect. It therefore follows that the targets of ELF fields in the mT
range will be the plaque cells (T-lymphocytes, macrophagic monocytes,
microglia cells and dendritic cells), those cells disseminated in the
seemingly normal nervous tissue (macrophages and microglia cells)
(Bistolfi, 2007).
More specifically, the target should be the plasma
membrane of these cells, which is almost always carpeted with microvilli
and protrusions of various types. Since the plasma membrane is central
to the relationships among immune cells (Lassmann et al., 2007) and
since the plasma membrane itself is the elective target of ELF-EMF, a
possible induction of the Marinozzi effect could slow down the activity
of autoimmune cells in the plaque. It may determine an effect of local
(on the brain) or regional immunomodulation (on the entire CNS) (Baureus
Koch et al., 2003).
In far 1998, Richards et al. (1998) expressed the hope
that electromagnetic fields might find application in the therapy of MS,
both to manage symptoms and to achieve long-term effects by eliciting
beneficial changes in the immune system and in nerve regeneration.
Our personal hypothesis is that – as
observed in MS – similar effects could be present and relevant during
EMF brain stimulation in patients with other CNS neurodegenerative
disorders and be responsible for their therapeutic effect.
Low-frequency Electromagnetic Fields Stimulation and Immunomodulation
ELF-EMF effects on macrophages, nitric oxide and heat shock proteins
Macrophages are responsible for
eliminating infectious agents and other cellular debris (Tintut et al.,
2002). The recruitment of monocytes/macrophages to inflammatory sites
and neoplastic tissues and their activation therein is crucial to the
success of an immune reaction, in part because further cell migration is
intimately related to leukocyte function. Resting macrophages have low
levels of phagocytic activity and become fully active through the
binding of pathogens or by local cytokine release. Once activated,
macrophages exhibit an increased level of phagocytic activity and an
increased production of reactive oxygen species (ROS) enabling the
killing of microbes within phagosomes. The first step is the
phagocytosis of the infectious agent, which is then transferred to the
phagosome where it is killed by ROS and reactive nitrogen oxide species.
The main protagonist of this process is nitric oxide (NO), which in
turn induces the formation of cGMP, which in turn triggers a cascade of
intracellular signaling. In the other hand, ROS also act as a signaling
molecule and targets a wide range of physiological pathways. Activation
of these cellular pathways also causes the secretion of inflammatory
cytokines including IL-1b and TNF-alpha (Laskin and Laskin, 2001).
Therefore when stimulated with bacterial toxins, NO and ROS stimulate
cells to synthesize heat shock proteins (HSPs) (Polla et al., 1996).
Several studies have shown the effect of ELF-EMFs on
macrophages. Kawczyk-Krupka and colleagues aimed to determine the effect
of ELF-EMFs on the physiological response of phagocytes to an
infectious agent. Human monocytic leukemia cell lines were cultured and
50 Hz, 1 mT EMF was applied for 4–6 hours to cells induced with
Staphylococcus aureus. The growth curve of exposed bacteria was lower
than the control, while field application increased NO levels. The
increase was more prominent for Staphylococcus aureus-induced cells and
appeared earlier than the increase in cells without field application
(Kawczyk-Krupka et al., 2002). Increased cGMP levels in response to
field application were closely correlated with increased NO levels
(Azanza and del Moral, 1994).
Another study on mouse macrophages after short-term (45
minutes) exposure to 50 Hz EMF at 1.0 mT showed a significant uptake of
carboxylated latex beads in macrophages, suggesting EMFs stimulate the
phagocytic activity of their macrophages (Frahm et al., 2006).
Tetradecanoylphorbol acetate (TPA) was used as positive control to prove
the activating capacity of cells, as TPA is known to activate the
protein kinase C and induce cellular processes including pinocytosis and
phagocytosis (Laskin et al., 1980). On the basis of these data, ELF-EMF
seems to potentially play a role in decreasing the growth rate of
bacteria and other pathogens eliminated by phagocytosis.
A significant increase of free radical production has been
observed after exposure to 50 Hz electromagnetic fields at a flux
density of 1 mT to mouse macrophages (Aktan, 2004). To elucidate whether
NADPH- or NADH-oxidase functions are influenced by EMF interaction, the
flavoprotein inhibitor diphenyleneiodonium chloride (DPI) was used.
EMF-induced free radical production was not inhibited by DPI, whereas
TPA-induced free radical production was diminished by approximately 70%.
Since DPI lacks an inhibitory effect in EMF-exposed cells, 50 Hz EMF
stimulates the NADH-oxidase pathway to produce superoxide anion
radicals, but not the NADPH pathway. Furthermore, the oscillation in
superoxide anion radical release in mouse macrophages suggests a cyclic
pattern of NADH-oxidase activity (Rollwitz et al., 2004).
An important aspect of these phagocytic cells is that they
produce high levels of free radicals in response to infection, and the
effect of ELF-EMF on free radicals has been widely proposed as a
probable direct mechanism for the action of ELF-EMF on the living
systems (Simko and Mattsson, 2004).
NO, a free radical, is an intra-cellular and
inter-cellular signaling molecule and it constitutes an important host
defense effector for the phagocytic cells of the immune system. It is
synthesized by NO synthase, which has two major types: “constitutive”
and “inducible”. Inducible nitric oxide synthase (iNOS) is particularly
expressed in macrophages and other phagocytic cells that are stimulated
during an immune response to infection (Aktan, 2004). Although high
concentration of NO can be beneficial as an antibacterial and antitumor
agent, an excess of NO can be fatal and can lead to cell injury. For
example the excessive activity of iNOS has detrimental effects on
oligodendrocytes, cells responsible for the myelination of neuron in the
CNS (Klostergaard et al., 1991). The roles of NO in the pathophysiology
of disease are still being defined, but there is a growing body of
evidence that the neutralization of iNOS activity may have a therapeutic
value (Parmentier et al., 1999).
Some studies have focused on the potential toxicity of the
ensuing high-output NO-synthesis serving as a mean to eliminate
pathogens or tumor cells, but the expression of iNOS, contributes to
local tissue destruction during chronic inflammation. NO increases the
ability of monocytes to respond to chemotactic agents more effectively,
and it is considered to be one of the principal effector molecules
involved in macrophage-mediated cytotoxicity (Desai et al., 2003).
It has been observed that exposure to ELF-EMFs modifies
both NOS and MCP-1 chemokine expression and that these modifications are
related to each other and are furthermore mediated by increased NF-?B
protein expression (Goodman et al., 1994). EMF represents a
non-pharmacological inhibitor of NO and an inducer of MCP-1, the latter
of which activates one of these molecules and leads to inhibition of the
former and vice versa, establishing a mechanism that protects
cells from excess stimulation and contributes to the regulation of
cellular homeostasis (Biswas et al., 2001). Moreover in vitro
study observed a slight decrease was observed in iNOS levels was
observed in cells induced with Staphlococcus aureus after ELF-EMF
stimulation (Azanza and del Moral, 1994).
HSPs are evolutionarily conserved
proteins known to play a key role in cellular defense against the effect
of stressors and their function in modulating apoptosis has been well
assessed (Beere, 2004). Concerning the relationship between EMF stimulus
and HSPs expressions, Goodman et al. (1994) first demonstrated that HSP
expression was enhanced by exposure to electromagnetic fields. Tokalov
and Gutzeit (2004) showed the effect of ELF-EMF on heat shock genes and
demonstrated that even a low dose of ELF-EMF (10 mT) caused an increase
in HSPs, especially hsp70, implying that the cell senses ELF-EMF as a
physical stressor.
ELF-EMF stimulation and oxidative stress
Oxidative stress derives from two
primary sources: 1) chronic ROS creation that is generated from the
mitochondrial electron transport chain during normal cellular function;
2) high levels of acute ROS generation resulting from nicotinamide
adenine dinucleotide phosphate (NADPH) oxidase, particularly associated
with the activation of the CNS immune system (Barja, 1998). In both
circumstances, oxidative stress comes up when an imbalance between ROS
production and clearance of radical species occurs.
ROS have been implicated as second messengers that
activate protein kinase cascades, although the means by which ROS
regulate signal transduction remains unclear. ROS release and cytokine
production, such as IL-1?, are common cell activation markers in immune
relevant cells. ROS is involved in the activation of IL-1? signal
transduction pathway (Li and Engelhardt, 2006). To neutralize the
detrimental effects of ROS, cells have evolved a hierarchy of
sophisticated antioxidant response mechanisms regulated by NF-E2-related
factor 2 (Nrf2) transcription factor (Tasset et al., 2010).
Environmental factors including EMFs, stressors or
diseases that augment the former or lower the latter can amplify and
drive the process. Thus, in practical terms, oxidative stress is
determined by excessive exposure to oxidant molecules when there is
insufficient availability of antioxidant mechanisms, with the resulting
free ROS oxidizing vulnerable cellular constituents, including proteins,
nucleic acids and lipids, inducing microglial activation, inducing
pro-inflammatory and suppressing anti-inflammatory cytokines and related
signaling pathways and ultimately causing both synaptic and neuronal
damage and dysfunction (Bonda et al., 2010). Whereas most environmental
electromagnetic radiations cause oxidative stress in the brain (Sahin
and Gumuslu, 2007), ELF-EMF seems to have an antioxidant and
neuroprotective effect (Medina and Tunez, 2010).
As shown by Tunez et al. (2006), ELF-EMF induces the
antioxidant pathway Nrf2, which is closely associated with its
protective effect against neurotoxicity induced by 3-nitropropionic acid
(3-NP) (Tunez et al., 2006). This effect may be due to the induction of
Nrf2, increasing its concentration in the nucleus as a result, at least
in part, on its translocation from the cytoplasm to the nucleus. These
changes in antioxidant systems were associated with a reduction of cell
and oxidative damage biomarkers. In fact given that Nrf2 regulates the
expression of antioxidant protein systems, its decrease may plausibly be
related to a reduction in antioxidant system levels. Thus, the
depletion of Nrf2 showed that 3-NP induced a significant decrease in
antioxidant enzyme activity in the striatum and an intense depletion of
glutathione levels. This was accompanied by clear and intense oxidative
damage characterized by lipid and protein oxidation, an increase in cell
death and damage markers and neuronal loss. Thus, the reduction in Nrf2
in both cytoplasm and nucleus may have been due to significant cell
loss induced by 3-NP (Tunez et al., 2006).
Animal studies have demonstrated that ELF-EMF exposure, in
the form of TMS (60 Hz, 0.7 mT) applied to rats for 2 hours twice
daily, can be neuroprotective (Tunez et al., 2006; Tasset et al., 2012).
Administered prior to and after a toxic insult to the brain, for
example in the systemic injection of 3-nitropropionic acid to induce an
animal model of Huntington’s disease (Tunez and Santamaria, 2009),
ELF-EMF can mitigate oxidative damage, elevate neurotrophic protein
levels in brain and potentially augment neurogenesis (Arias-Carrion et
al., 2004).
EMF 1.0 mT exposure of mouse macrophages showed a
significant increase in extracellular IL-1b release after only 4 hours
of exposure, which was continuously increased after 12–24 hours of
exposure. This data suggests that EMF stimulation is able to increase
cytokines in murine macrophages. Cossarizza and colleagues described the
increased release of IL-2, IL-1, and IL-6 in peritoneal lymphocytes
after long-term exposure to ELF-EMF (Cossarizza et al., 1989). On the
other hand, investigation on cytokine production by Pessina et al.
showed no effects after EMF on peritoneal blood cells (Pessina and
Aldinucci, 1998).
Beyond these results, such studies
reiterate the importance that the cellular effects of ELF-EMFs depend,
in a large part, on their intensity and exposure time, as well as on the
phenotype of the cellular target and interactions with intracellular
structures. The level and timing of exposure can potentially be
scheduled to optimize endogenous compensatory mechanisms following an
adverse reaction.
ELF-EMF effects on pro-inflammatory chemokines
Chemokines are produced by a variety of
cells including monocytes, T lymphocytes, neutrophils, fibroblasts,
endothelial cells and epithelial cells (Murdoch and Finn, 2000).
Chemokines play a relevant role in inflammatory events, such as
trans-endothelial migration and accumulation of leucocytes at the site
of damage. In addition, they modulate a number of biological responses,
including enzyme secretion, cellular adhesion, cytotoxicity, T-cell
activation and tissue regeneration (Zlotnik and Yoshie, 2000).
Since their discovery, chemokines have emerged as
important regulators of leukocyte trafficking, and MCP-1, one of the
best-studied chemokines, is known to exert multiple effects on target
cells, such as increased cytosolic calcium levels, superoxide anion
production, lysosomal enzyme release, production of anti-inflammatory
cytokines and adhesion molecules in monocytes. MCP-1 is involved in the
induction of polarized type Th2 responses and in the enhancement of IL-4
production. A possible feedback loop for Th2 activation would be the
production of IL-4 and IL-13 by Th2, which stimulates MCP-1 production
and leads to further recruitment of Th2 cells (Moser and Loetscher,
2001).
The fine control of inflammatory mediator levels is
critical to neuronal homeostasis and health. For example, a deficiency
in neuronal TGF-? signaling promotes neurodegeneration and AD, whereas
augmented TGF-? can act as an anti-inflammatory cytokine and has
potential neuroprotective action in AD and following other insults to
the central nervous system (Ren et al., 1997).
Studies have shown the anti-inflammatory effects of ELF-EMF in vivo;
for instance, Selvam used a coil system emitting a 5 Hz frequency to
treat rats with rheumatoid arthritis for 90 minutes, producing
significant anti-exhudative effects and resulting in the restoration of
normal functional parameters (Vianale et al., 2008). This
anti-inflammatory effect was reported to be partially mediated through
the stabilizing action of ELF-EMF on cell membranes, reflected the
restoration of intracellular Ca2+ levels in plasma
lymphocytes (Selvam et al., 2007). Other investigators have suggested
that ELF-EMF can interact with cells through mechanisms that involve
extracellular calcium channels (Cho et al., 1999).
Moreover, incubating mononuclear cells
with an iNOS inhibitor showed a significant reduction of iNOS and an
increase of MCP-1 levels, and these effects are consistent with iNOS and
MCP-1 level modifications observed in mononuclear cells exposed to
ELF-EMF. Selective inhibition of the NF-?B signaling pathway by ELF-EMF
may be involved in the decrease of chemokine production. If so, ELF-EMF
exposure, interfering with many cellular processes, may be included in
the plethora of stimuli that modulate NF-?B activation (including
pro-inflammatory cytokines such as tumor necrosis factor-? and IL-1?,
chemokines, phorbol 12-myristate 13-acetate, growth factors,
lipopolysaccharide, ultraviolet irradiation, viral infection, as well as
various chemical and physical stresses) (Vianale et al., 2008).
Lymphocyte activity and electrotaxis: a possible link to ELF-EMF stimulation
Recent studies have shown that cells can directionally respond to applied electric fields, in both in vitro and in vivo
settings, a phenomenon called electrotaxis. However, the exact cellular
mechanisms for sensing electrical signals are still not fully well
understood, and it is thus far unknown how cells recognize and respond
to electric fields, although some studies have suggested that
electro-migration of some cell surface receptors and ion channels in
cells could be involved (Cortese et al., 2014). Directed cell migration
is essential to numerous physiological processes including immune
responses, wound healing, cancer metastasis and neuron guidance (Kubes,
2002). Normal blood lymphocytes and monocytes respond to a steady
electric field in Transwell assays. All lymphocyte subsets, including
naive and memory CD4+, CD8+ T cells and B cells
migrated toward the cathode. Electrotaxisis highly directional and the
uniform migration of circulating lymphocytes suggests that other
leukocyte subsets (e.g., tissue memory cells) may undergo electrotaxis as well.
Lymphocytes respond to electric fields with activation of
Erk-kinases and Akt, which are involved in chemo-attractant receptor
signaling and in electrotactic signaling in other cells (Sotsios et al.,
1999; Zhao et al., 2006). Activation of these pathways suggests that
electrotaxis and chemotaxis engage common intracellular cell motility
programs in responding lymphocytes. In fact, electric field exposure
induces Erk1/2 and Akt activation in lymphocytes, consistent with the
activation of the MAPK and PI3K signaling pathways implicated in
coordinated cell motility. Furthermore, it has been proven that an
applied electric field induced the electrotactic migration of endogenous
lymphocytes to mouse skin (Lin et al., 2008). These data thus define
electrotaxis andpotentially present an additional mechanism for the
control of lymphocyte and monocyte migration.
ELF-EMFs can either inhibit or stimulate
lymphocyte activity as a function not only of the exposure (Petrini et
al., 1990), but also of the biological conditions to the cells are
exposed, with mitogen-activated cells being more responsive than resting
cells (Conti et al., 1986). To explain this ambivalence of the effects
of ELF magnetic fields on the immune system, Marino and colleagues have
presented the hypothesis that the biological effects of ELF magnetic
fields are governed by non-linear laws, and that deterministic responses
may therefore occur that are both real and inconsistent, thereby
yielding two conflicting types of results (Marino et al., 2000). A
particular role in the interaction of ELF-EMFs with lymphocytes seems to
be played by the mobilization of intracellular Ca2+from the calciosomes and of extracellular Ca2+
through the membrane channels (Conti et al., 1985). The action of
ELF-EMFs on lymphoid cells, however, can also be exerted on the
functions of the plasma membrane: the duration of the ligand-receptor
bond (Chiabrera et al., 1984), the clustering of membrane proteins
(Bersani et al., 1997), the activity of enzymatic macro-molecules
(Lindstrom et al., 2001), and the active ion pumps (Ca2+ ATPase and Na+ K+ATPase).
Conclusions
Several studies have shown that ELF-EMF
exposure is able to activate primary monocytes and macrophages from
different species and also in cell lines. This activation potential is
comparable to the activation by certain chemicals resulting in
physiologically relevant cellular responses.
In the past, several findings have demonstrated the
efficacy of pulsed ELF-EMFs of a few mT in alleviating the symptoms of
MS through their action on synaptic neurotransmission and autoimmunity
(by determining cell membrane changes in plaques).
Moreover, ELF-EMF exposure contributes to a general
activation of macrophages, resulting in changes of numerous
immunological reactions, such as increased ROS formation, in an enhanced
phagocytic activity, and in an increased IL-1? release. Therefore, we
can deduce that EMFs activate physiological functions of immune cells.
However, the underlying mechanisms of interaction between EMF and immune
system are still to be completely understood and need further studies
at the molecular level.
Animal studies have demonstrated that ELF-EMF exposure, in
the form of transcranial magnetic stimulation (60 Hz, 0.7 mT) applied
to rats for 2 hours twice daily, has been seen to be neuroprotective
(Sahin and Gumuslu, 2007; Medina and Tunez, 2010).
The effects of low flux density magnetic fields are
exerted on altered functional states, in the sense of hyper- or
hypo-function, rather than on normal functional states. The
neurophysiological interpretation is that neurotransmission is favored
at various sites: partially synapses, the cerebellum, and
interhemisphere transcallosal connections, an idea which is strongly
supported by the rapid regression seen in certain symptoms in patients
with MS (Sandyk, 1995b). Based on all these evidences such effect could
be attributed to the correction of perturbations of synaptic
conductivity and immunomodulation (Bistolfi, 2007), resulting in
clinical therapeutic effect as observed in neurodegenerative disorders
such as AD (Mruthinti et al., 2006; Attems and Jellinger, 2014).
However, so far there is still no general agreement on the
exact biological effect elicited by EMFs on the physical mechanisms
that may be behind their interaction with biological systems. Of course
the biological effects of EMFs are dependent on frequency, amplitude,
timing and length of exposure, but are also related to intrinsic
susceptibility and responsiveness of different cell types (Tenuzzo et
al., 2006). Level and timing of exposure can be potentially scheduled to
optimize endogenous compensatory mechanisms following an adverse
challenge.
In the light of results reviewed here, we conclude that
there is growing evidence of the potential role of EMFs in biological
modulation of autoimmunity, immune functions and oxidative stress. As a
consequence, the hypothesis that ELF-EMFs explicit their therapeutic
effect through modulation of immune relevant cells is of clear interest,
in particular in neurodegenerative diseases.
It is notable to underline that the effects of ELF-EMFs
are not unique as they depend on their intensity, exposure time and
cellular targets; further efforts towards more scheduled and well
defined level and timing of exposure should be warranted.
Hence, it is necessary to proceed with
substantial research on this issue, paying particular attention to the
choice of the appropriate biological model and controlled experimental
conditions.
Footnotes
Conflicts of interest:The
authors report no conflicts of interest in this work. This research did
not receive any specific grant from funding agencies in the public,
commercial, or not-for-profit sectors.
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Articles from Neural Regeneration Research are provided here courtesy of Medknow Publications
Behav Brain Funct. 2015; 11: 26. Published online 2015 Sep 7. doi: 10.1186/s12993-015-0070-z
Mechanisms and therapeutic applications of electromagnetic therapy in Parkinson’s disease.
Parkinson’s disease (PD) is one of the most common neurodegenerative
diseases worldwide, second only to Alzheimer’s disease (AD) [1]. PD is
accompanied by the impairment of the cortico-subcortical excitation and
inhibition systems, hence belonging to the involuntary movement diseases
[2]. PD is caused by progressive loss of structure and function of
dopaminergic neurons in the ventral tegmental area and substantia nigra
pars compacta in the midbrain with subsequent damage to the basal
ganglia (BG) [3]. Cumulative evidence supports the hypothesis that PD is
the result of complex interactions among genetic abnormalities,
environmental toxins and mitochondrial dysfunction [4–6]. The mechanisms
of neuronal degeneration characterizing PD have been studied
extensively and include a complex interplay among multiple pathogenic
processes including oxidative stress, protein aggregation,
excitotoxicity and impaired axonal transport [7]. The increasing number
of genes and proteins critical in PD is unraveling a complex network of
molecular pathways involved in its etiology, suggesting that common
mechanisms underlie familial and sporadic PD, the two forms of this
pathology. While the sporadic form is the most common (90–95% of PD
cases), only 5–10% of PD cases are familial [8, 9]. At least ten
distinct loci are responsible for rare Mendelian forms of PD and
mutations in five genes have been linked to familial PD [10]. PD is
characterized by motor and non-motor symptoms. The main motor symptoms
include bradykinesia, tremor at rest (tremor affecting the body part
that is relaxed or supported against gravity and not involved in
purposeful activities [11]), rigidity and postural instability [12–17].
However, motor symptoms are now considered as the “tip of the iceberg”
of PD clinical manifestations. PD non-motor symptoms include cognitive
decline, decrease in sleep efficiency, increased wake after sleep onset,
sleep fragmentation, and vivid dreams as well as neuropsychiatric
symptoms such as depression and psychosis, [18–23]. Pain syndrome and
autonomic dysfunctions have also been observed in PD patients [24–26].
Neuroimaging and genes: towards a personalized medicine for Parkinson’s disease
Several research groups have begun to perform genome-wide association
studies (GWAS) on data or index measures derived from brain images,
with the final goal of finding new genetic variants that might account
for abnormal variations in brain structure and function that increase
the risk of a given disease. Numerous genes have been identified using
GWAS and have been associated with PD. They include alpha-synuclein,
vacuolar protein sorting-associated protein 35, human leukocyte antigen
family, leucine-rich repeat kinase 2 and acid ?-glucosidase [27–29].
Neuroimaging associates individual differences in the human genome to
structural and functional variations into the brain. Van der Vegt and
colleagues reported structural and functional brain mapping studies that
have been performed in individuals carrying a mutation in specific PD
genes including PARK1, PARK2, PARK6, PARK7, PARK8, and discussed how
this “neurogenetics-neuroimaging approach” provides unique means to
study key PD pathophysiological aspects [30]. In addition, neuroimaging
of presymptomatic (non-manifesting) mutation carriers has emerged as a
valuable tool to identify mechanisms of adaptive motor reorganization at
the preclinical stage that may prevent or delay PD clinical
manifestation [30]. Neuroimaging may be useful to study the
effectiveness of electromagnetic therapy in PD patients.
Available therapies for Parkinson’s disease
PD treatment includes the use of pharmacological agents such as the
dopaminergic agent l-3,4-dihy-droxy-phenylalanine (Levodopa or l-dopa)
and stereotactic brain surgery which are associated with numerous side
effects [31]. For example, the on-and-off phenomenon includes profound
diurnal fluctuations in the psychomotor state of PD patients treated
with l-dopa [32]. Furthermore, l-dopa loses effectiveness over time and
can induce motor fluctuations such as the “wearing off” effect and
dyskinesia [33]. While l-dopa metabolites are neurotoxic [33], the
search for alternate, non-dopaminergic therapies to overcome the
l-dopa-induced side effects has positioned adenosine A2A receptor (A2AR)
antagonists as a promising therapeutic option for PD treatment [34].
Despite the favorable features of A2AR antagonists, their
pharmacological properties, such as poor oral bioavailability and the
lack of blood–brain barrier permeability, constitute a major problem to
their clinical application [35]. Furthermore, regular physiotherapy and
instrumental rehabilitation that have been employed to manage PD
symptoms, such as tremor, slowness and difficulty in walking, are only
moderately helpful [36]. Electromagnetic therapy has also been
extensively used for PD treatment and may represent a promising
therapeutic option for this condition since it promotes a lasting
improvement in motor and non-motor symptoms [37–41].
Electromagnetic therapy background
Electromagnetic therapy includes the use of six groups of
electromagnetic fields as previously described [42, 43] and summarized
below:
Static/permanent magnetic fields can be created by various permanent
magnets as well as by passing direct current through a coil.
Transcranial magnetic stimulation (TMS) utilizes frequencies in the range 1–200 Hz.
Low-frequency electromagnetic fields mostly utilize 60 Hz (in the US and
Canada) and 50 Hz (in Europe and Asia) frequencies in distribution
lines.
Pulsed radiofrequency fields utilize frequencies in the range 12–42 MHz.
Millimeter waves refer to very high-frequency in the range 30–100 GHz.
Pulsed electromagnetic fields (PEMFs) utilize frequencies in the range 5–300 Hz with very specific shapes and amplitudes.
Electromagnetic therapy is defined as the use of time-varying
electromagnetic fields of low-frequency values (3 Hz–3 kHz) that can
induce a sufficiently strong current to stimulate living tissue [44].
Electromagnetic fields can penetrate all tissues including the
epidermis, dermis, and subcutaneous tissue, as well as tendons, muscles
and bones [45]. The amount of electromagnetic energy used and its effect
on the target organ depends on the size, strength and duration of
treatment [44]. Electromagnetic fields can be divided into two
categories: static and time-varying. Electromagnetic therapy falls into
two categories: (1) hospital use which includes TMS, repetitive
transcranial magnetic stimulation (rTMS) and high-frequency TMS and (2)
home use including PEMF therapy.
Aim and searching criteria
We searched Pubmed/Medline using the keywords “Parkinson’s Disease”
combined with “electromagnetic therapy”, “TMS”, “rTMS”, “high-frequency
TMS” or “PEMF” and we included articles published between 1971 and 2015.
This article aims to review the state of the art of electromagnetic
therapy for treatment of PD.
Transcranial magnetic stimulation
TMS is a safe and non-invasive method of electrical stimulation of
neurons in the human cerebral cortex, modifying neuronal activity
locally and at distant sites when delivered in series of pulses [46].
TMS is also a useful tool to investigate various aspects of human
neurophysiology, particularly corticospinal function, in health and
disease [47]. An electromagnetic field generator sends a current with a
peak amplitude of about 8,000 A that lasts about 1 ms, through an
induction coil placed on the scalp [48]. TMS is based on the principle
of electromagnetic induction, as discovered by Faraday in 1838. The
current flowing briefly in the iron coil placed over a patient’s head
generates an electromagnetic field that penetrates the scalp and skull
reaching the brain where it induces a secondary ionic current. The site
of stimulation of the brain is the point along its length at which
sufficient current passes through its membrane to cause depolarization
[49]. TMS can be used to determine several parameters associated to
different aspects of cortical excitability: (1) the resting motor
threshold or active motor threshold which reflects membrane properties;
(2) the silent period, which is a quiescent phase in the electromyogram
(EMG), is partially of cortical origin and is related to the function of
gamma-aminobutyric acid receptors; (3) the short intracortical
inhibition and facilitation which occur when a subthreshold stimulus
precedes a suprathreshold stimulus by less than 5 ms or 8–30 ms,
respectively. The peak of electromagnetic field strength is related to
the magnitude of the current and the number of turns of wire in the coil
[50]. The electrical current is rapidly turned on and off in the coil
through the discharge of electronic components called the capacitors.
Transcranial magnetic stimulation in Parkinson’s disease
TMS clinical applications were first reported by Barker and
colleagues who stimulated the brain, spinal cord and peripheral nerves
using TMS with low or no pain [51]. Following this work, several TMS
protocols that evidenced the correlation of TMS with peripheral EMG and
monitored the modulation of TMS-induced motor evoked potentials (MEPs),
were described [52–54]. For example, Cantello and coworkers studied the
EMG potentials evoked in the bilateral first dorsal interosseus muscle
by electromagnetic stimulation of the corticomotoneuronal descending
system in 10 idiopathic PD patients without tremor but with rigidity
with asymmetric body involvement and 10 healthy controls [55]. The
threshold to cortical stimulation measured on the rigid side of PD
patients was lower than on the contralateral side or than normal values.
PD patients’ MEPs on the rigid side were larger compared to controls
when the cortical stimulus was at rest or during slight tonic
contraction of the target muscle [55]. Several clinical trials have
pointed out the therapeutic efficacy of TMS in PD patients [3, 31, 56,
57]. For example, biomagnetic measurements performed using
magnetoencephalography (MEG) in 30 patients affected by idiopathic PD
exposed to TMS evidenced that 60% of patients did not exhibit tremor,
muscular ache or dyskinesias for at least 1 year after TMS therapy [58].
The patients’ responses to TMS included a feeling of relaxation,
partial or complete disappearance of muscular ache and l-dopa-induced
dyskinesias as well as rapid reversal of visuospatial impairment [58].
Additional MEG measurements in PD patients also showed abnormal brain
functions including slowing of background activity (increased theta and
decreased beta waves) and increased alpha band connectivity [59]. These
changes may reflect abnormalities in specific networks and
neurotransmitter systems, and could be useful for differential diagnosis
and treatment monitoring.
Repetitive transcranial magnetic stimulation
rTMS is a non-invasive technique of brain stimulation based on
electromagnetic induction [60]. rTMS has the potential to alter cortical
excitability depending on the duration and mode of stimulation [61].
The electromagnetic pulse easily passes through the skull, and causes
small electrical currents that stimulate nerve cells in the targeted
brain region [62]. Since this type of pulse generally does not reach
further than two inches into the brain, it is possible to selectively
target specific brain areas [62]. Generally, the patient feels a slight
knocking or tapping on the head as the pulses are administered. rTMS
frequencies of around 1 Hz induce an inhibitory effect on cortical
excitability [63] and stimulus rates of more than 5 Hz generate a
short-term increase in cortical excitability [64]. rTMS induces a MEP of
the muscles of the lower extremities by stimulating the motor and
supplementary motor area (SMA) of the cerebral cortex [31].
Repetitive transcranial magnetic stimulation in Parkinson’s disease
Several studies have reported the efficacy of rTMS on PD motor
symptoms [65–69]. These effects are primarily directed at surface
cortical regions, since the dopaminergic deficiency in PD is localized
to the subcortical BG. The BG comprises a group of interconnected deep
brain nuclei, i.e. the caudate and putamen, globus pallidus, substantia
nigra and the subthalamic nucleus (STN) that, through their connections
with the thalamus and the cortex, primarily influence the involuntary
components of movement and muscle tone [70]. Several studies have
documented the long-term effects of rTMS applied to PD patients for
several days, rather than single sessions [71–73]. For instance,
Shimamoto and coworkers applied rTMS on a broad area including the left
and right motor, premotor and SMAs in nine PD patients for a period of 2
months, and observed improvements in the Unified Parkinson’s Disease
Rating Scale (UPDRS), a rating scale used to follow PD progression [74].
A further trial in PD patients reported a shortened interruption of
voluntary muscle contraction, defined cortical silent period, suggesting
a disturbed inhibitory mechanism in the motor cortex [57]. PD patients
show altered activation patterns in the SMA and overall less
cortico-cortical excitability [75–81] that play a key role in motor
selection in sequentially structured tasks, including handwriting. In a
randomized controlled trial with a crossover design in PD patients, rTMS
applied over the SMA influenced several key aspects of handwriting,
e.g. vertical size and axial pressure, at least in the short term [82].
Ten PD patients treated with rTMS, evidenced short-term changes in
functional fine motor task performance. rTMS over the SMA compensated
for cortico-striatal imbalance and enhanced cortico-cortical
connections. This treatment improved PD patients deficits such as
reduction in speed during the writing task and decrease in letter size
(micrographia).
Two mechanisms have been proposed to explain how cortically directed
rTMS may improve PD symptoms: (1) rTMS induces brain network changes and
positively affects the BG function; (2) rTMS directed to cortical sites
compensates for PD-associated abnormal changes in cortical function
[60]. Indeed, in support of the former mechanism, rTMS might modulate
cortical areas, such as the prefrontal cortex and primary motor cortex,
which are substantially connected to both the striatum and STN via
glutamatergic projection, and thus indirectly modulate the release of
dopamine in the BG [83]. Several TMS/functional imaging studies have
demonstrated the effects of rTMS on BG and an increase in dopamine in
the BG after rTMS applied to the frontal lobe [84].
rTMS can also transiently disrupt the function of a cortical target
creating a temporary “virtual brain lesion” [85–87]. Mottaghy and
coworkers have studied the ability of rTMS to produce temporary
functional lesions in the BG, an area involved in working memory, and
correlated these behavioral effects with changes in regional cerebral
blood flow in the involved neuronal network [88]. Functional imaging and
TMS studies in PD subjects have shown altered cortical physiology in
areas associated to the BG such as the SMA, dorsolateral prefrontal
cortex and primary motor cortex [57, 89], characterized by excessive
corticospinal output at rest, concomitant to, or resulting from a
reduced intracortical inhibition [60]. These altered changes in cortical
function in PD patients might avoid the suppression of competing motor
areas and therefore decrease the motor system performance, resulting in
symptoms such as tonic contractions and rigidity [89].
rTMS has not only been applied to a motor area of the brain but has
also been used to target PD non-motor deficits. For example, in a study
involving six PD patients with mild cognitive impairment, a cognitive
dysfunction defined by deficits in memory, rTMS was delivered over the
frontal region at 1.2 times the motor threshold (minimum stimulation
intensity) of the right abductor pollicis brevis muscle [3]. Over a
period of 3 months, rTMS was performed for a total of 1200 stimulations.
Improvement in neuropsychological tests (the trail-making test part B
and the Wisconsin card-sorting test) was observed in all patients. In
addition, an improvement in subjective symptoms and objective findings
were also observed by the subjects, their families, and the therapists.
The changes observed in PD subjects included “faster reactions”, “better
body movement and smoother standing-up and movement”, “more active”,
“more cheerful”, and “more expressive”. An increase in the amount of
conversation, an increase in the neural mechanisms of mutual
understanding within daily living and an improvement in responses to
visitors were also noted, if compared to baseline. Additionally, changes
such as better hand usage while eating and better sleep were also
observed.
Cognitive dysfunction is often seen in PD patients with major
depression and its neural basis could be the functional failure of the
frontostriatal circuit [3, 90]. Ten days of rTMS in the frontal cortex
can effectively alleviate PD-associated depression as shown by an open
trial reporting a significant decrease in the Hamilton Depression Rating
Scale (HDRS) scores [91]. A further double blind, sham
stimulation-controlled, randomized study, involving 42 idiopathic PD
patients affected by major or minor depression undergoing rTMS for 10
days, evidenced a mean decrease in HDRS and Beck depression inventory
after therapy [92].
In opposition to the above mentioned positive reports concerning the
efficacy of rTMS in PD patients, a lack of effectiveness of rTMS on
objective or subjective symptoms has also been described. For example,
in a study involving 85 idiopathic PD patients, no significant
differences in clinical features were observed between patients
receiving rTMS and sham stimulation [65]. Moreover, total and motor
score of UPDRS were improved by rTMS and sham stimulation in the same
manner. Despite this improvement, PD patients treated with rTMS revealed
signs of depression, reporting no subjective benefits. In another
randomized crossover study, 10 patients affected by idiopathic PD
received rTMS to the SMA which resulted in subclinical worsening of
complex and preparatory movement [93]. The rTMS protocol was not
tolerated by 2 out of 10 patients. Furthermore, this study showed that,
following rTMS, subtle regional disruption can persist for over 30 min,
raising safety concerns. A further randomized crossover study involving
11 patients with idiopathic PD, treated with rTMS over the motor cortex,
did not show any therapeutic effect on concurrent fine movement in PD
[94].
In summary, conflicting findings regarding the efficacy of rTMS in PD
have been reported and they can be explained by differences in
stimulation parameters, including intensity, frequency, total number of
pulses, stimulation site and total number of sessions. Therefore,
further studies comparing different parameters are required.High-frequency transcranial magnetic stimulation
High-frequency TMS consists of continuous high-frequency stimulation of
specific brain regions, including the motor cortex, cerebellum and BG,
through implanted large four-contact electrodes connected to a pulse
generator and positioned into the center of the target region [70]. Such
stimulation induces an electrical field that spreads and depolarizes
neighboring membranes of cell bodies, afferent and efferent axons,
depending on neuronal element orientation and position in the field and
on stimulation parameters [95]. Optimal clinical results are obtained by
using pulses of 60–200 ms duration and 1–5 V amplitude, delivered in
the STN at 120–180 Hz [96]. For example, high-frequency TMS produces a
transient blockade of spontaneous STN activity, defined HFS-induced
silence. During HFS-induced silence, the persistent Na+ current is
totally blocked and the Ca2+-mediated responses are strongly reduced,
suggesting that T- and L-type Ca2+ currents are transiently depressed by
high-frequency TMS [97].Indeed, recent evidence suggests that the
stimulation of the motor cortex, the cerebellum and the BG not only
produces inhibitory and excitatory effects on local neurons, but also
influences afferent and efferent pathways. Therefore, the mechanism of
action of high-frequency TMS depends on changes in neural activity
generated in the stimulated, afferent and efferent nuclei of the BG and
motor cortex [98].High-frequency transcranial magnetic stimulation in Parkinson’s disease
In the first PD patients treated with high-frequency TMS in 1993,
motor symptoms, tremor, rigidity and akinesia improved significantly
allowing to decrease the administration of l-dopa by a mean of 55% [99].
Since then, several thousands of patients worldwide have been fitted
with high-frequency TMS implants achieving marked improvements in their
symptoms, making this method the reference procedure for advanced PD
[100]. The time course of improvement following high-frequency TMS
treatment differs for different cardinal symptoms of PD [101]. For
instance, rigidity and resting tremor decrease immediately, within a few
seconds after high-frequency TMS [102]. Different clinical effects are
observed in PD patients depending on the site of stimulation [103]. For
example, stimulation of the ventral intermediate nucleus of the thalamus
can dramatically relieve PD-associated tremor [104]. Similarly,
stimulation of the STN or globus pallidus interna (GPi) can
substantially reduce rigidity, tremor, and gait difficulties in patients
affected by idiopathic PD [105]. Stimulation of the GPi also reduces
all of the major PD motor manifestations, including the reduction of
l-dopa-induced dyskinesias and involuntary movements produced by
individual doses of dopaminergic medications that can limit treatment
efficacy [106]. Thalamic stimulation in the region of the ventral
intermediate nucleus reduces limb tremor but it has little effect on
other manifestations of the disease [107]. In order to explain the
beneficial effects of high-frequency TMS, two fundamental mechanisms
have been proposed by Garcia and coworkers: silencing and excitation of
STN neurons [95]. They reported that high-frequency TMS using stimulus
parameters that yield therapeutic effects has a dual effect, i.e. it
suppresses spontaneous activity and drives STN neuronal activity.
High-frequency TMS switches off a pathological disrupted activity in the
STN (i.e. silencing of STN neurons mechanism) and imposes a new type of
discharge in the upper gamma-band frequency (60–80 Hz range) that is
endowed with beneficial effects (i.e. excitation of STN neurons
mechanism) [95]. This improvement generated by high-frequency TMS is due
to parallel non-exclusive actions, i.e. silencing of ongoing activity
and generation of an activity pattern in the gamma range [108]. There is
an important advantage in silencing spontaneous activity and generating
a pattern: the signal to noise ratio and the functional significance of
the new signal are enhanced [109].
Techniques and preparations employed to study the mechanisms of
high-frequency TMS include electrophysiological techniques, measurement
of neurotransmitter release in vivo, post-mortem immunohistochemistry of
a metabolic marker such as cytochrome oxidase and imaging studies in
vivo [95]. Such results consistently show a post-stimulus period of
reduced neuronal firing followed by the slow recovery of spontaneous
activity. High-frequency TMS, at frequencies >50 Hz, applied to the
STN of PD patients undergoing functional stereotactic procedures
[110–112], to the STN of rats in vivo [113, 114] and rat STN slices in
vitro [97, 115, 116], produces a period of neuronal silence of hundreds
of milliseconds to tens of seconds. During brief high-frequency TMS in
PD patients off medication and in the murine model of parkinsonism
obtained by acute injections of neurotoxin
1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine for 5 consecutive days, a
reduced STN activity, as response to stimulation, is observed at 5–14 Hz
and this response is frequency-dependent [114]. High-frequency TMS has
two main advantages: (a) it reduces the time a patient spends in the
“off” state because the individual dose of these profound diurnal
fluctuations leaves a person slow, shaky, stiff, and unable to rise from
a chair; (b) it allows the reduction of medications and their
consequent side effects [117].
Pulsed electromagnetic field therapy
PEMF therapy is a non-static energy delivery system, characterized by
electromagnetic fields inducing microcurrents in the target body tissues
[118]. These microcurrents elicit specific biological responses
depending on field parameters such as intensity, frequency and waveform
[119]. The benefits of PEMF therapy have been observed in several
clinical studies for treatment of several medical conditions including
knee osteoarthritis [120], shoulder impingement syndrome [121], lower
back pain [122, 123], multiple sclerosis [124, 125], cancer [121, 123,
125, 126], PD [127], AD [128] and reflex sympathetic dystrophy syndrome
[129]. A large number of PEMF therapy devices contains user-friendly
software packages with pre-recorded programs with the ability to modify
programs depending on the patient’s needs [43, 130–132]. Examples of
PEMF devices are the Curatron® (Amjo Corp, West Chester, PA, USA),
Seqex® system (S.I.S.T.E.M.I. Srl, Trento, Italy), MRS 2000®, iMRS®,
QRS® (all produced by Swiss Bionic Solutions Schweiz GmbH, Dulliken,
Switzerland) and TESLA Stym (Iskra Medical, Ljubljana, Slovenia).
Pulsed electromagnetic field therapy in Parkinson’s disease
In October 2008 the Food and Drug Administration approved the use of
PEMF therapy for treatment of major depressive disorder in PD patients
who failed to achieve satisfactory improvement from very high dosages of
antidepressant medications [133, 134]. Several studies reported PEMF
therapy improved cognitive functions and motor symptoms. For example, an
investigation involving three elderly PD patients with cognitive
impairment assessed the effect of PEMF therapy on macrosomatognosia, a
disorder of the body image in which the patient perceives a part or
parts of his body as disproportionately large [135]. After receiving
PEMF therapy, PD patients’ drawings showed reversal of macrosomatognosia
(assessed by Draw-a-Person test) with reduction of the right parietal
lobe dysfunction. Furthermore, PEMF therapy applied to a 49-year-old
male PD patient with stage 3 disease, as assessed by Hoehn and Yahr
scale, resulted in a marked improvement in motor and non-motor symptoms
such as mood swings, sleeplessness, pain and sexual and cognitive
dysfunctions, suggesting that PEMF therapy should be tested in large
cohorts of PD patients as monotherapy and should also be considered as a
treatment modality for de novo diagnosed PD patients [136]. PEMF
therapy was also effective in improving visuospatial deficits in four PD
patients, as assessed by the clock-drawing test [137]. Moreover, PEMF
therapy improved PD-associated freezing (a symptom manifesting as a
sudden attack of immobility usually experienced during walking) in 3 PD
patients through the facilitation of serotonin neurotransmission at both
junctional and non-junctional neuronal target sites [127].
Discussion
Although many studies on electromagnetic therapy included only a small
number of participants, several investigations suggest that this therapy
is effective in treating PD patients’ motor and non-motor symptoms. In
the development of electromagnetic therapies, it is important to clarify
the pathophysiological mechanisms underlying the symptoms to treat in
order to determine the appropriate brain region to target. Thus, in the
future, electromagnetic therapy must tend towards a more personalized
approach, tailored to the specific PD patient’s symptoms. All the types
of electromagnetic therapy described in this review can be used in
combination with pharmacological and non-pharmacological therapies but
this approach is understudied in PD patients. Therefore, specific
protocols should be designed and tested in combination with other
therapies in future controlled trials in patients affected by PD.
Transcranial magnetic stimulation
TMS increases the release of dopamine in the striatum and frontal
cortex, which in turn improves PD symptoms including motor performance
[138]. Furthermore, TMS applied in the prefrontal cortex induces the
release of endogenous dopamine in the ipsilateral caudate nucleus as
observed by positron emission tomography in healthy human subjects [89].
TMS application results in partial or complete disappearance of
muscular pain and l-dopa-induced dyskinesia as well as regression of
visuospatial impairment. This clinical improvement is followed by MEG
improvement and normalization recorded after TMS, suggesting that TMS
has an immediate and beneficial effect on corticostriatal interactions
that play an important role in the pathophysiology of PD [58]. Cerasa
and coworkers observed that repetitive TMS applied over the inferior
frontal cortex reduced the amount of dyskinesia induced by a
supramaximal single dose of levodopa in PD patients, suggesting that
this area may play a key role in controlling the development of
dyskinesia [139]. The mechanism underlying TMS effectiveness in PD
remains an unanswered question due to the complexity of behavioral and
neuroendocrine effects exerted by the TMS when applied to biological
systems and their potential impact on neurotransmitter functions [140].
The effect of TMS differs depending on the stage of the disease, the age
of disease onset, the amount of cerebral atrophy and genetic factors
[37]. TMS has a low cost and is simple to operate and portable, opening
the possibility for patients to perform at home stimulation which could
be of high relevance in the elderly and in patients who are severely
disabled. As far as side effects are concerned, the muscles of the
scalp, jaw or face may contract or tingle during the procedure and mild
headache or brief lightheadedness may occur [141, 142]. A recent
large-scale study on the safety of TMS found that most side effects,
such as headaches or scalp discomfort, were mild or moderate, and no
seizures occurred [143]. Although evidence shows that TMS exerts complex
cellular, systemic and neuroendocrine effects on biological systems
impacting neurotransmitter functions [58], future controlled studies in
larger cohorts of patients and with a long term follow-up are needed to
further clarify the mechanisms underlying TMS efficacy in PD patients.
Repetitive transcranial magnetic stimulation
rTMS can be defined as a safe and non-invasive technique of brain
stimulation which allows to specifically treat PD with low-frequency
electromagnetic pulses [60]. As opposed to high-frequency TMS, which can
induce convulsions in healthy subjects, rTMS does not affect the
electroencephalogram pattern [71, 144]. Slow waves have been induced by
rTMS over the right prefrontal area, a brain area involved in executive
dysfunction that is observed in early stages of PD and is characterized
by deficits in internal control of attention, set shifting, planning,
inhibitory control, dual task performance, decision-making and social
cognition tasks [3, 145]. rTMS applied to PD patients, enhances not only
executive function, but also motor function, subjective symptoms and
objective findings [3]. rTMS also increases cognitive function and other
symptoms associated to the prefrontal area in PD patients [146]. In PD
patients, therapeutic efficacy and long-term benefits of rTMS are
obtained following multiple regular sessions rather than single
sessions, but side effects associated to this therapy still warrant
investigation in large controlled trials.
High-frequency magnetic stimulation
The observations that STN activity is disorganized in PD patients and
that a lesion or chemical inactivation of STN neurons ameliorate motor
symptoms led to the hypothesis that high-frequency TMS silences STN
neurons and, by eliminating a pathological pattern, alleviates PD
symptoms [147–151]. Garcia and colleagues proposed another hypothesis
suggesting that high-frequency TMS suppresses not only the pathological
STN activity but also imposes a new activity on STN neurons [95]. They
proposed that high-frequency TMS excites the stimulated structure and
evokes a regular pattern time-locked to the stimulation, overriding the
pathological STN activity. As a consequence, high-frequency TMS removes
the STN spontaneous activity and introduces a new and regular pattern
that improves the dopamine-deficient network [95]. Elahi and coworkers
found that high-frequency TMS modulates the excitability of the targeted
brain regions and produces clinically significant motor improvement in
PD patients [66]. This improvement is due to parallel non-exclusive
actions, i.e. silencing of ongoing activity and generation of an
activity pattern in the high gamma range [152]. Several clinical studies
reported positive clinical results following high-frequency TMS in
l-dopa-responsive forms of PD, including patients with selective brain
dopaminergic lesions [153]. It remains unclear whether the mechanisms of
action of high-frequency TMS and l-dopa are similar or they could be
even synergic. However, high-frequency TMS improves the l-dopa-sensitive
cardinal motor symptoms of PD patients with benefits similar to those
given by l-dopa, though with reduced motor complications [154, 155]. The
interactions with the dopaminergic system seem to be a key factor
explaining the efficacy of both treatments [156]. High-frequency TMS
changes dopamine lesion-induced functional alterations in the BG of PD
animal models and gives an insight into the mechanisms underlying its
antiparkinsonian effects [114, 157, 158]. The intrinsic capacity of the
BG to generate oscillations and change rapidly from a physiological to a
pathogenic pattern is crucial; the next step will be to identify how
high-frequency TMS is propagated inside the BG. Disadvantages of this
therapy are the high cost and limited availability of the devices to
specialized medical centers, limited knowledge of potential long-term
side effects and the necessity to employ highly trained personnel.
Pulsed electromagnetic fields
PEMF therapy improves PD symptoms including tremor, slowness of
movement and difficulty in walking [159]. It is non-invasive, safe and
improves PD patients’ quality of life [124, 160]. PEMF therapy, employed
for PD treatment, supports the body’s own healing process for 4–6 h
after therapy session [161–163]. It can be used at home and applied to
the entire body or locally to target a specific body area and, if
compared with dopaminergic systemic therapy, e.g. l-dopa, it can offer
an alternative treatment avoiding systemic side effects such as
hepatotoxicity and nephrotoxicity.
Conclusions
Electromagnetic therapy opens a new avenue for PD treatment. Each
electromagnetic therapy technique described in this review can be
applied according to a single protocol or as a combination of different
protocols specifically tailored to the PD patient’s needs. Beyond the
necessity to choose coil or electrode size and placement, there is a
variety of parameters that have to be taken into account when designing
electromagnetic therapy approaches and they include stimulation
intensity, duration, frequency, pattern, electrode polarity and size.
Furthermore, electromagnetic therapy can also be combined with
pharmacological or non-pharmacological treatments, e.g. physical therapy
and cognitive tasks, to produce additive or potentiated clinical
effects. In conclusion, electromagnetic therapy represents a
non-invasive, safe and promising approach that can be used alone or
combined with conventional therapies for the challenging treatment of PD
motor and non-motor symptoms.
Authors’ contributions
MV, AV, LP, BP, JCMM, and TI contributed equally to this review. All authors read and approved the final manuscript.
Acknowledgements
JCMM thanks CONACyT, México for membership. The authors thank Iskra
Medical (Stegne 23, 1000 Ljubljana, Slovenia) for supporting the open
access publication of this article.
Compliance with ethical guidelines
Competing interests The authors declare that they have no competing interests.
Contributor Information
Maria Vadalà, Email: moc.liamg@aladav.yram.
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Neuropsychiatr Dis Treat. 2015 Sep 18;11:2391-404. doi: 10.2147/NDT.S90966. eCollection 2015.
An innovative intervention for the treatment of
cognitive impairment-Emisymmetric bilateral stimulation improves
cognitive functions in Alzheimer’s disease and mild cognitive
impairment: an open-label study.
Guerriero F1, Botarelli E2, Mele G2, Polo L2, Zoncu D2,
Renati P3, Sgarlata C4, Rollone M5, Ricevuti G6, Maurizi N4, Francis
M4, Rondanelli M7, Perna S7, Guido D8, Mannu P2.
.
Author information
1Department of Internal Medicine and Medical Therapy, Section of
Geriatrics, University of Pavia, Pavia, Italy ; Agency for Elderly
People Services, Santa Margherita Hospital, Pavia, Italy ; Ambra
Elektron, Italian Association of Biophysics for the Study of
Electromagnetic Fields in Medicine, Turin, Italy.
2Ambra Elektron, Italian Association of Biophysics for the Study of Electromagnetic Fields in Medicine, Turin, Italy.
3Ambra Elektron, Italian Association of Biophysics for the Study of
Electromagnetic Fields in Medicine, Turin, Italy ; Alberto Sorti
Research Institute, Medicine and Metamolecular Biology, Turin, Italy.
4Department of Internal Medicine and Medical Therapy, Section of Geriatrics, University of Pavia, Pavia, Italy.
5Agency for Elderly People Services, Santa Margherita Hospital, Pavia, Italy.
6Department of Internal Medicine and Medical Therapy, Section of
Geriatrics, University of Pavia, Pavia, Italy ; Agency for Elderly
People Services, Santa Margherita Hospital, Pavia, Italy.
7Department of Public Health, Experimental and Forensic Medicine,
Section of Human Nutrition, Endocrinology and Nutrition Unit, University
of Pavia, Pavia, Italy.
8Agency for Elderly People Services, Santa Margherita Hospital, Pavia,
Italy ; Department of Public Health, Experimental and Forensic Medicine,
Biostatistics and Clinical Epidemiology Unit, University of Pavia,
Pavia, Italy.
Abstract BACKGROUND AND AIMS:
In the last decade, the development of different methods of brain
stimulation by electromagnetic fields (EMF) provides a promising
therapeutic tool for subjects with impaired cognitive functions.
Emisymmetric bilateral stimulation (EBS) is a novel and innovative EMF
brain stimulation, whose working principle is to introduce very weak
noise-like stimuli through EMF to trigger self-arrangements in the
cortex of treated subjects, thereby improving cognitive faculties. The
aim of this pilot study was to investigate in patients with cognitive
impairment the effectiveness of EBS treatment with respect to global
cognitive function, episodic memory, and executive functions.
METHODS:
Fourteen patients with cognitive decline (six with mild cognitive
impairment and eight with Alzheimer’s disease) underwent three EBS
applications per week to both the cerebral cortex and auricular-specific
sites for a total of 5 weeks. At baseline, after 2 weeks and 5 weeks, a
neuropsychological assessment was performed through mini-mental state
examination, free and cued selective reminding tests, and trail making
test. As secondary outcomes, changes in behavior, functionality, and
quality of life were also evaluated.
RESULTS:
After 5 weeks of standardized EBS therapy, significant improvements were
observed in all neurocognitive assessments. Mini-mental state
examination score significantly increased from baseline to end treatment
(+3.19, P=0.002). Assessment of episodic memory showed an improvement
both in immediate and delayed recalls (immediate recall =+7.57, P=0.003;
delayed recall =+4.78, P<0.001). Executive functions significantly
improved from baseline to end stimulation (trail making test A -53.35
seconds; P=0.001). Of note, behavioral disorders assessed through
neuropsychiatric inventory significantly decreased (-28.78, P<0.001).
The analysis concerning the Alzheimer’s disease and mild cognitive
impairment group confirmed a significant improvement of cognitive
functions and behavior after EBS treatment.
CONCLUSION:
This pilot study has shown EBS to be a promising, effective, and safe
tool to treat cognitive impairment, in addition to the drugs presently
available. Further investigations and controlled clinical trials are
warranted.
KEYWORDS:
Alzheimer’s disease; Emisymmetric bilateral stimulation; cognitive decline; pulsed electromagnetic fields
J Alzheimer’s Dis. 2012;32(2):243-66. doi: 10.3233/JAD-2012-120943.
Transcranial electromagnetic treatment against Alzheimer’s disease:
why it has the potential to trump Alzheimer’s disease drug development.
Arendash GW.
Source
Department of Cell Biology, University of South Florida, Tampa, FL, USA. arendash@cas.usf.edu
Abstract
The universal failure of pharmacologic interventions against
Alzheimer’s disease (AD) appears largely due to their inability to get
into neurons and the fact that most have a single mechanism-of-action. A
non-invasive, neuromodulatory approach against AD has consequently
emerged: transcranial electromagnetic treatment (TEMT). In AD transgenic
mice, long-term TEMT prevents and reverses both cognitive impairment
and brain amyloid-B (AB) deposition, while TEMT even improves cognitive
performance in normal mice. Three disease-modifying and inter-related
mechanisms of TEMT action have been identified in the brain: 1) anti-AB
aggregation, both intraneuronally and extracellularly; 2) mitochondrial
enhancement; and 3) increased neuronal activity. Long-term TEMT appears
safe in that it does not impact brain temperature or oxidative stress
levels, nor does it induce any abnormal histologic/anatomic changes in
the brain or peripheral tissues. Future TEMT development in both AD mice
and normal mice should involve head-only treatment to discover the most
efficacious set of parameters for achieving faster and even greater
cognitive benefit. Given the already extensive animal work completed,
translational development of TEMT could occur relatively quickly to
“proof of concept” AD clinical trials. TEMT’s mechanisms of action
provide extraordinary therapeutic potential against other neurologic
disorders/injuries, such as Parkinson’s disease, traumatic brain injury,
and stroke.
PLoS One. 2012; 7(4): e35751.
Published online 2012 April 25. doi: 10.1371/journal.pone.0035751
PMCID: PMC3338462
Electromagnetic Treatment to Old Alzheimer’s Mice Reverses B-Amyloid
Deposition, Modifies Cerebral Blood Flow, and Provides Selected
Cognitive Benefit
Gary W. Arendash,1,2,* Takashi Mori,3 Maggie Dorsey,4 Rich Gonzalez,5 Naoki Tajiri,6 and Cesar Borlongan61
Department of Cell Biology, Microbiology, and Molecular Biology,
University of South Florida, Tampa, Florida, United States of America, 2 The Florida Alzheimer’s Disease Research Center, Tampa, Florida, United States of America, 3
Departments of Biomedical Sciences and Pathology, Saitama Medical
Center and Saitama Medical University, Kawagoe, Saitama, Japan, 4 The University of South Florid Health Byrd Alzheimer’s Institute, Tampa, Florida, United States of America, 5 SAI of Florida, Redington Beach, Florida, United States of America, 6
Center of Excellence for Aging and Brain Repair, Department of
Neurosurgery and Brain Repair, University of South Florida, Morsani
College of Medicine, Tampa, Florida, United States of America
Efthimios M. C. Skoulakis, Editor
Received December 27, 2011; Accepted March 22, 2012.
Few studies have investigated physiologic and cognitive
effects of “long-term” electromagnetic field (EMF) exposure in humans or
animals. Our recent studies have provided initial insight into the
long-term impact of adulthood EMF exposure (GSM, pulsed/modulated, 918
MHz, 0.25–1.05 W/kg) by showing 6+ months of daily EMF treatment
protects against or reverses cognitive impairment in Alzheimer’s
transgenic (Tg) mice, while even having cognitive benefit to normal
mice. Mechanistically, EMF-induced cognitive benefits involve
suppression of brain B-amyloid (AB) aggregation/deposition in Tg mice
and brain mitochondrial enhancement in both Tg and normal mice. The
present study extends this work by showing that daily EMF treatment
given to very old (21–27 month) Tg mice over a 2-month period reverses
their very advanced brain A? aggregation/deposition. These very old Tg
mice and their normal littermates together showed an increase in general
memory function in the Y-maze task, although not in more complex tasks.
Measurement of both body and brain temperature at intervals during the
2-month EMF treatment, as well as in a separate group of Tg mice during a
12-day treatment period, revealed no appreciable increases in brain
temperature (and no/slight increases in body temperature) during EMF
“ON” periods. Thus, the neuropathologic/cognitive benefits of EMF
treatment occur without brain hyperthermia. Finally, regional cerebral
blood flow in cerebral cortex was determined to be reduced in both Tg
and normal mice after 2 months of EMF treatment, most probably through
cerebrovascular constriction induced by freed/disaggregated A? (Tg mice)
and slight body hyperthermia during “ON” periods. These results
demonstrate that long-term EMF treatment can provide general cognitive
benefit to very old Alzheimer’s Tg mice and normal mice, as well as
reversal of advanced A? neuropathology in Tg mice without brain heating.
Results further underscore the potential for EMF treatment against AD.
Introduction
Despite the best efforts of pharmaceutical industry and
academia, no new drugs against Alzheimer’s Disease (AD) have been
developed since 2003 [1].
Moreover, currently available drugs (acetylcholinesterase inhibitors
and/or N-metyle D-aspartate (NMDA) antagonists) only treat/mask AD
symptoms for about one year, if at all – none of them directly slow or
lessen AD pathogenesis itself. In view of the universal failure of every
major drug trial to alter the course of AD, it is time to think outside
the “pharmaceutical box” by considering non-pharmaceutical approaches
that are safe, disease modifying, and can be expeditiously explored to
treat AD. We propose high frequency electromagnetic field (EMF)
treatment could be that approach, based on several epidemiologic studies
[2], [3] and our recently completed EMF studies in Alzheimer’s transgenic (Tg) mice [4], [5].
In humans, high frequency EMF exposure/treatment studies
have essentially involved “cell phone level” EMF parameters (pulsed,
modulated and primarily GSM), in large part because of initial concerns
that high frequency EMF exposure may induce health problems such as
brain cancer [6], [7]. However, the recent 13-nation INTERPHONE study [8], as well as analytic findings from NIEHS [9] and numerous epidemiologic studies [10]–[12],
all collectively conclude that there is no consistent evidence that
long-term exposure of adults or children/adolescents to cell phone level
EMFs causes brain tumors, or very likely any other health problems for
that matter. In concert with these studies alleviating safety issues
related to high frequency EMF exposure, dozens of studies have
investigated potential cognitive and physiologic (i.e., EEG, cerebral
blood flow, and auditory processing) effects of cell phone level EMF
exposure. With rare exception [13], [14],
these studies only involved brief (3–120 minute), single EMF exposure
at GMS, CW, or UMTS cell phone parameters given to normal subjects. Not
surprisingly, recent reviews/meta-analyses find these “acute” exposure
studies to result in no significant beneficial or impairing effects on
cognitive performance [15], [16].
Nonetheless, several PET studies have reported that acute,
single-exposure EMF treatment can affect regional cerebral blood flow [17], [18] and increase brain glucose utilization [19], thus suggesting that even acute high frequency EMF treatment can affect brain neuronal activity.
Although results from acute, single EMF exposure studies
are insightful, they are most probably not indicative of the physiologic
and cognitive effects of long-term/daily EMF exposure (i.e. the EMF
exposure typical of cell phone users or the repeated EMF treatments
almost certainly required for any clinical EMF applications). In this
context, no controlled human studies have investigated the “long-term”
effects of high frequency EMF treatment in normal or AD subjects over
weeks, months, or years. Nonetheless, two epidemiologic studies have
provided initial human evidence that years of high frequency EMF
exposure are associated with cognitive benefit. One of these studies
found that heavy cell phone use over several years resulted in better
performance of normal subjects on a word interference test [2],
while the other study reported that long-term cell phone users (>10
years) had a 30–40% decreased risk of hospitalization due to AD and
vascular dementia [3].
The lack of controlled human studies investigating
cognitive effects of “long-term” EMF exposure/treatment has at least
been partially negated by our highly controlled EMF treatment studies in
AD Tg mice and littermate non-transgenic (NT) mice [4], [5]. In the first long-term, high frequency EMF treatment study evaluating cognition in adult humans or animals [4],
we reported that treatment (at cell phone levels of 918 MHz/0.25–1.05
W/kg; pulsed and modulated) over 7–9 months prevented or reversed
cognitive impairment in AD Tg mice bearing the APPsw mutation. Even
normal mice showed EMF-induced cognitive enhancement in that initial
study. For AD mice, the primary mechanism of cognitive benefit appears
to be a suppression of brain A? aggregation into neuritic plaques,
presumably resulting in greater A? efflux from the brain [4].
Moreover, the cognitive benefits of long-term EMF treatment to both AD
mice and normal mice occurs without any evidence of tissue abnormalities
in either the brain or peripheral tissues, without any evidence of
increased oxidative stress in the brain, and without any increase in DNA
damage to circulating blood cells. Thus, long-term EMF treatment in
mice appears safe in having no deleterious side effects across multiple
sensitive markers of brain/body function.
In a second study that involved AD Tg mice bearing the
APPsw+PS1 double mutation, we reported that daily EMF treatment for one
month enhances the impaired brain mitochondrial function of these AD
mice, as well as the brain mitochondrial function of normal mice [5].
These EMF-induced mitochondrial enhancements occurred through
“non-thermal” mechanisms because brain temperatures were either stable
or decreased during and after daily high frequency EMF treatments. Since
this EMF-induced mitochondrial enhancement in AD mice was linked to
dramatic 5–10 fold elevations in soluble A? within the same
mitochondria, EMF treatment disaggregated toxic A? oligomers therein,
apparently resulting in very high monomeric A? levels (which are
innocuous to mitochondrial function). Our mitochondrial function results
in Dragicevic et al. [5]
collectively suggest that brain mitochondrial enhancement may be a
primary mechanism through which long-term EMF treatment provides
cognitive benefit to both AD mice and NT mice.
In a third study, we have most recently reported that two
months of daily EMF treatment enhances neuronal activity in the
entorhinal cortex of aged Alzheimer’s Tg mice and littermate NT mice [20].
This EMF-induced enhancement of neuronal activity was temporally linked
to cognitive benefit in the same animals. Based on these results, we
have suggested that EMF treatment could be a viable approach to counter
the neuronal hypo-activity that occurs very early in AD pathogenesis [20].
It is noteworthy that our prior EMF studies [4], [5], [20]
identified the first biologic mechanisms that could explain the
EMF-induced cognitive benefits, which we also reported in normal and
Alzheimer’s Tg mice (i.e., anti-A? aggregation, mitochondrial
enhancement, and enhanced neuronal activity). The fact that our
long-term EMF treatment involves pulsed, modulated GSM signal is
important because a recent, comprehensive review concluded that
EMF-induction of biologic effects occurs primarily with GSM-type
modulation and a pulsed signal – not continuous wave or UMTS fields [21].
Our initial behavioral study in AD Tg mice involved
long-term EMF treatment to young adult APPsw mice (from 2–7.5 months of
age), as well as to older APPsw adults (from 5–13.5 months of age) [4].
Inasmuch as A? pathology was not yet well established when treatment
began for these mice, the beneficial effects reported were most relevant
to human EMF treatment in pre-symptomatic/prodromal AD or in mild
cognitive impairment (MCI), the prelude to AD. The present study extends
our earlier findings by evaluating the impact of long-term EMF
treatment given to very old 21–26 month-old APPsw and APPsw+PS1 mice,
both of which bear much heavier brain A? burdens/A? levels than the
APPsw mice in our initial work. In these aged mice with advanced A?
pathology, we evaluated an array of behavioral, neuropathologic, and
physiologic measures to get a clearer understanding of how long-term EMF
treatment might impact the aged and heavily A?-burdened brain. We
report a profound ability of long-term EMF treatment to reverse brain A?
deposition, induce changes in regional cerebral blood flow, and provide
selected cognitive benefits – all without induction of brain
hyperthermia.
Results
Behavioral assessment during long-term EMF treatment
In Study I, behavioral testing of aged Tg and NT mice
between 1 and 2 months into daily EMF treatment indicated no deleterious
effects of EMF treatment on sensorimotor function (Table 1).
For both Tg and NT mice, general activity/exploratory behavior was
unaffected by EMF treatment, as indexed by open field activity and
Y-maze choices made. As well, balance and agility abilities were not
impacted in either Tg or NT mice by EMF treatment, as indexed by balance
beam and string agility performance. In both of these tasks, however,
an overall effect of genotype was presence, with Tg mice having poorer
balance/agility compared to NT mice irrespective of EMF treatment
(p<0.002). Finally, visual acuity testing in the visual cliff task at
the end of behavioral testing (2 months into EMF treatment) indicated
no deleterious effects of EMF treatment on vision in either Tg or NT
mice.
Sensorimotor measures in NT and Tg mice given long-term EMF treatment.
For cognitive-based tasks/measures, EMF effects were task
specific with benefits observed in the Y-maze task, but no effects in
either the circular platform or radial arm water maze (RAWM) tasks. In
the Y-maze alternation task of general mnemonic function, both Tg and NT
mice being given EMF treatment showed near-significance increases in
percent alternation compared to their respective controls (Fig. 1A,
left). Because there was no difference in performance of Tg and NT
mice, these genotypic groups were combined to determine if an overall
EMF treatment effect was present. Indeed, a significant increase in
spontaneous alternation percentage was evident irrespective of genotype (Fig. 1A,
right), indicating a beneficial effect of EMF treatment on general
mnemonic function. In the circular platform task of spatial/reference
memory, Tg mice were impaired vs. NT controls during the final (2nd block) of testing, irrespective of whether they were receiving EMF treatment or not (Fig. 1B).
Furthermore, EMF treatment did not improve the poor performance (e.g,
high escape latencies) of both Tg and NT mice in this task.
Cognitive performance of non-transgenic (NT) and APPsw
transgenic (Tg) mice in the Y-maze task of spontaneous alternation (Fig.
1A) and the circular platform task of spatial/reference memory (Fig.
1B).
For the RAWM task of working memory, all animals were
tested prior to the start of EMF treatment to establish baseline
performance levels and to determine if a transgenic effect was present.
Throughout pre-treatment RAWM testing, both Tg and NT mice showed the
high escape latencies typically seen during the naïve first trial (T1),
as exemplified by the last block of pre-treatment testing (Fig. 2A).
By contrast, Tg mice showed a severe working memory impairment compared
to NT mice at individual test blocks and overall, as exemplified by
their substantially higher escape latencies during working memory Trial 5
(T5) for the last block of pre-treatment testing (Fig. 2A).
Following completion of pre-treatment testing, Tg mice were divided
into two sub-groups balanced in RAWM performance (as were NT mice), with
one sub-group receiving EMF treatment and the other group not. Ensuing
RAWM testing at both 1 month and 1.5 months into EMF treatment continued
to show substantially impaired working memory (T5) performance in Tg
mice vs. NT controls, irrespective of whether they were receiving EMF
treatment or not (Figs. 2B, C).
The similar T5 working memory impairment of Tg+EMF mice and Tg controls
(evident during individual blocks and overall) is exemplified by the
last block of testing, as shown in Figs. 2B and C.
Working memory in the radial arm water maze (RAWM) task
pre-treatment, 1 month, and 1.5 months into EMF treatment for the naïve
first trial (T1) and working memory trial (T5) of APPsw transgenic (Tg)
and non-transgenic (NT) mice.
Thus, EMF-induced cognitive benefits to very old AD and NT
mice were selective in enhancing general mnemonic function (Y-maze
alternation), but not impacting spatial reference learning/memory
(circular platform) or working memory (radial arm water maze).
Body/brain temperature recording during long-term EMF treatment
Study I
Body and brain temperature measurements were attained from
aged animals in Study I before start of EMF treatment (control) and at
1, 3, and 6 weeks into treatment (final temperature measurements were
unfortunately not taken at the 2-month termination point of this study).
Throughout the 6-week study period, body and brain temperature
recordings indicated very stable temperature in control NT and control
APPsw (Tg) mice not being given EMF treatment (Fig. 3).
By contrast, body temperature for both EMF-treated NT and Tg mice was
modestly elevated by 0.5–0.9°C during ON periods compared to OFF
periods, from 1 week into EMF treatment onward through treatment. For Tg
mice, this increase in body temperature during ON periods was evident
even on the first day of EMF treatment. During EMF OFF periods for both
NT and Tg mice, body temperature always came back down to their
pre-treatment levels. Since body temperature before start of EMF
treatment was identical for Tg mice (but not NT mice) to be given EMF or
sham treatment, temperature comparisons between these two groups
throughout the EMF treatment period also revealed that the elevated body
temperatures of Tg mice during ON periods always came back down to sham
control levels during OFF periods.
Body and brain temperature measurements for non-transgenic
(NT) and APPsw transgenic (Tg) mice recorded prior to the start of EMF
treatment (control), and at 1 Day, 1 week, 3 weeks, and 6 weeks into EMF
treatment.
As indicated in Fig. 3,
brain temperature in control NT and Tg mice was usually 0.3–0.4°C lower
than body temperature, which is typically the case for rodents [22].
As with body temperatures, brain temperature measurements in control NT
and Tg mice (not given EMF treatment) were very stable throughout the
study. In EMF-treated NT mice, elevations of 0.3–0.4°C in brain
temperature during ON periods were evident and significant by 3 weeks
into treatment (Fig. 3).
In EMF-treated Tg mice, however, only trends for a slight increase in
brain temperature were present during ON periods. Thus, even with
peripheral increases in temperature during ON periods, brain temperature
remained stable or was only elevated minimally through 6 weeks of EMF
exposure. Following any brain temperature elevations during ON periods,
brain temperature always returned to pre-treatment levels during OFF
periods.
Study II
For the aged APPsw+PS1 (Tg) mice in Study II, body and
brain temperature measurements were taken before the start of EMF
treatment, as well as at 5 and 12 days into treatment (Fig. 4).
Though still modest, the difference between body and brain temperature
measurements for control APPsw+PS1 mice throughout this study was larger
(0.7–0.9°C) than for the body/brain temperature differences of APPsw
mice throughout Study I. Despite receiving the same daily EMF exposure
as APPsw mice in Study I, APPsw+PS1 mice in this study showed no
significant increase in body or brain temperature during ON periods at 5
and 12 days into EMF treatment. For all time points evaluated, there
were no differences between EMF-treated and control Tg mice in either
body or brain temperature.
Body and brain temperature measurements for APPsw+PS1
transgenic (Tg) mice recorded prior to the start of EMF treatment
(control), as well as at 5 days and 12 days into EMF treatment.
Cerebral blood flow measurements during long-term and sub-chronic EMF treatment
Laser Doppler measurements of regional cerebral blood flow
(rCBF) in cerebral cortex were performed at 2 months into EMF treatment
for Study I and at 12 days into EMF treatment for Study II. In Study I,
control NT and Tg mice (not being given EMF treatment) had very
consistent rCBF readings between their sham ON and OFF periods (Fig. 5A).
Although NT+EMF mice exhibited no change in rCBF between ON and OFF
periods, Tg mice showed a significant 13% decrease in rCBF during the ON
period vs. OFF period (Fig. 5A).
The decreased rCBF present in Tg mice during the ON period was even
greater (?25%) in relation to rCBF in control Tg mice during their sham
ON period. Visual inspect of the data in Fig. 5A
revealed rCBF measurements during both OFF and ON periods to be lower
in EMF-treated mice compared to control (sham-treated) mice irrespective
of genotype. This, in addition to no genotypic differences in rCBF
being present for EMF-treated or control mice, warranted combination of
individual animal data from both genotypes to determine the main effect
of EMF during OFF and ON periods (Fig. 5B).
A significant decrease in rCBF was present not only during ON periods
for EMF vs. control mice, but also present during OFF periods as well.
Thus, EMF effects on rCBF were present not only during ON periods, but
also during OFF periods, at 2 months into EMF treatment.
Regional cerebral blood flow (rCBF) in cerebral cortex of
NT and Tg mice in Studies I and II obtained by Laser Doppler
measurements at the end of their 2 month and 12-day EMF treatment
periods, respectively.
rCBF measurements in Study II only involved Tg mice and at a shorter 12-days into the same daily EMF exposure. As shown in Fig. 5C, control Tg mice had stable and similar rCBF measurements during OFF and sham ON periods. By contrast, a nearly significant (p=0.10)
reduction in rCBF (?19%) was present in EMF-treated Tg mice during
their ON period vs. OFF period at 12 days into EMF exposure. Supportive
that a true EMF-induced decrease in rCBF had indeed occurred, 4 out of
five Tg+EMF mice had decreases of 7–46% in rCBF during the ON period
compared to the OFF period. The significantly higher rCBF present in
EMF-treated mice vs. control Tg mice during the OFF period was due to
several EMF-treated mice with high rCBF readings during both OFF and ON
periods.
AB immunohistochemistry
After two months of EMF treatment, the very old (23–28
months old) APPsw and NT mice in Study I were euthanized and their
brains processed for quantitative analysis of A? deposition. As
expected, NT mice exhibited no human A? immunostaining in their brains
irrespective of treatment. Very old Tg controls (Tg), however, had
extremely high levels of A? deposition in both their hippocampus and
entorhinal cortex, bearing A? burdens of 11–12% in these two brain areas
(Fig. 6B).
In sharp contrast, Tg mice that had received two months of EMF
treatment exhibited substantial decreases in A? burden within both
hippocampus (?30%) and entorhinal cortex (?24%) compared to Tg controls (Fig. 6B). Thus, EMF treatment reversed pre-existing A? deposition/plaque formation. Fig. 6A
shows representative photomicrographs of typical A?
immunostained-plaques from 23–28 months old Tg and Tg+EMF mice,
underscoring the substantial reduction in A? deposition present
in brains of very old Tg mice given a two-month period of daily EMF
treatment. Analysis of plasma samples taken at euthanasia revealed no
effects of EMF treatment on plasma A?1–40 (4620±442 pg/ml for Tg vs.
4885±920 pg/ml for Tg+EMF; p=0.78) or A?1–42 (1452±120 pg/ml for Tg vs. 1175±251 pg/ml; p=0.30).
Brain A deposition in APPsw transgenic (Tg) mice at 2 months after EMF treatment (Study I).
Discussion
We have previously reported that long-term (>6 months)
EMF exposure at cell phone level frequencies and SAR levels can protect
against or reverse cognitive impairment in Alzheimer’s Tg mice, while
even having cognitive benefit to normal mice [4].
Moreover, we previously provided the first mechanistic insight into
long-term EMF treatment by reporting the ability of such treatment to
suppress brain A aggregation/deposition in AD mice, while enhancing
brain mitochondrial function and neuronal activity in both Tg and normal
mice [4], [5], [20].
The present study extends the above works by administering long-term (2
months) of daily EMF treatment to very old Alzheimer’s Tg mice and
showing that such treatment can reverse their very advanced brain
aggregation/deposition while providing selected cognitive benefit to
both Tg and normal mice. Moreover, these neuropathologic and cognitive
benefits occurred without appreciable increases in brain temperature,
indicating involvement of non-thermal brain mechanisms (i.e., A?
anti-aggregation, mitochondrial enhancement, neuronal activity).
Finally, the present study is the first to determine the effects of
long-term EMF exposure on rCBF, and in the same animals evaluated for
cognitive, neuropathologic, and body/brain temperature endpoints. Our
finding of an EMF-induced decrease in cortical blood flow raises several
interesting mechanisms of action that merit consideration.
Cognitive and AB deposition effects of EMF treatment
Two months of cell phone level EMF treatment (e.g., GSM,
918 MHz, 0.25–1.05 W/kg, pulsed and modulated) improved the cognitive
performance of very old (23–27 month old) Tg and NT mice combined in the
Y-maze task of spontaneous alternation. This task evaluates general
mnemonic function and is not associated with brain A? levels/deposition [23].
Thus, generalized mechanisms irrespective of genotype, such as the
brain mitochondrial enhancement present by one month into EMF treatment [5], are most likely involved. The present Y-maze results are consistent with our initial study [4]
wherein we found Y-maze spontaneous alternation to be significantly
increased in NT mice given long-term EMF treatment. By contrast,
long-term EMF treatment was not able to reverse the cognitive impairment
in two tasks wherein performance is linked to brain A levels/deposition
– the circular platform task of spatial/reference memory and RAWM task
of working memory [23].
The RAWM task, in particular, is very sensitive to brain A deposition,
with poorer working memory performance highly correlated with extent of A
deposition in both hippocampus and cortex.
Although the very old Tg mice of this study had
extraordinarily high brain A burdens (11–12%) that were substantially
reduced (24–30%) by EMF treatment, this large quantitative reduction in
A? deposition was apparently not sufficient for cognitive benefit to
become manifest in tasks linked to brain A levels/deposition. A longer
EMF treatment period or more effective EMF parameters is probably needed
to attain widespread behavioral benefit in these very old Tg mice. In
our initial study [4],
6–7 months of daily EMF treatment was required to manifest widespread
cognitive benefit in younger Tg mice bearing only around 2% brain A?
burdens. Parenthetically, animals in the present study were given double
the daily EMF exposure (two 2-hour periods) compared to our initial
study (two 1-hour periods). For both studies, a more effective removal
of A from the brain through greater EMF-induced ? disaggregation and
ensuing greater removal of resultant soluble A from the brain into the
blood would appear to be key to realization of earlier cognitive
benefits.
It is important to underscore that an absolute reduction
in brain “soluble” A? is not required to get EMF-induced cognitive
benefits, as we have repeatedly demonstrated for various AD therapeutics
including EMF treatment [4], [24], [25].
This is because the disaggregating action of EMF treatment on brain A?
(from insoluble to soluble forms) appears to shift most soluble A? from
the cognitive-impairing “oligomeric” form to smaller (innocuous)
dimeric/monomeric forms. That is the probable reason why we observed
brain mitochondrial enhancement in aged Tg mice given long-term (1
month) EMF treatment despite those treated mice having 5–10× higher
soluble A? in their brain mitochondria (i.e., most of this soluble A?
was in innocuous monomeric/dimeric forms) [5].
Such enhanced levels of monomeric/soluble A? are also consistent with
the lack of EMF-induced reductions in plasma A? levels observed in the
present study, as well as in our earlier EMF study [4].
Prior to our recent study showing cognitive efficacy of
“cell phone-level” EMF exposure administered daily for >6 months to
Tg and normal mice [4],
animal studies investigating cognitive effects of cell phone level EMF
exposure involved “normal” mice/rats receiving daily “head-only” [26]–[28] or “full body” [29]
EMF exposure for a relatively short 4–14 days. No cognitive benefits
were reported in those studies, nor did longer 2- or 6-month periods of
daily head-only EMF exposure impact cognitive performance in normal rats
[28].
However, a 5-week period of cell phone level EMF exposure to immature
(3 weeks old) rats did improve their rate of learning in the Morris
water maze task [30].
It is important to note that future rodent studies emphasize
“head-only” EMF exposure over many months and utilize a comprehensive
array of cognitive measures/tasks (not simply a single measure/task).
In humans, all cell phone level EMF studies investigating
cognitive function have been unilateral and involved either single EMF
exposure [15], [16] or daily EMF exposure for 6–27 days [13], [14],
with no cognitive effects being reported in either case. However, one
study did report that heavy cell phone users evaluated over a 2-year
period performed better in a word interference test [2].
Clearly, there is a critical need for long-term, well-controlled EMF
studies in humans to evaluate cognitive effects in both normal and
cognitive-impaired individuals.
Body/brain temperature and cerebral blood flow effects of EMF treatment
Before our own recent work [4], [5]
and the present study, only one prior animal study investigated the
effects of EMF exposure on body/brain temperature and/or cerebral blood
flow [31].
That study, involving a single head-only GSM exposure for 18 minutes to
anesthetized rats, was at very high frequency (2000 MHz) and very high
SAR levels (10–263 W/kg). This acute EMF exposure increased brain
temperature in a dose-dependent fashion (by 1–12°C), and increased
cortical cerebral blood flow (by 30–70%). In humans, no studies
investigating EMF effects on brain temperature have apparently been done
in living individuals, and EMF effects on cerebral blood flow have only
involved a single, unilateral EMF exposure, with inconsistent results [16].
Thus, for both animals and humans, there had previously been no
investigations into long-term EMF effects on brain temperature or
cerebral blood flow.
Regarding temperature, our recent studies [4], [5]
have investigated both acute and long-term body/brain temperature
effects of EMF treatment (i.e., GSM, pulse/modulated at 918 MHz and
0.25–1.05 W/kg), with the following findings: 1) a single day of EMF
treatment has no effect on body or brain temperature of either AD Tg or
normal mice during ON periods; 2) At 8–9 months into daily EMF
treatment, body temperature of both Tg and NT mice is elevated by
approximately 1°C during ON periods; and 3) At 1 month into daily EMF
treatment, body temperature of aged Tg and NT mice is elevated by around
1°C during ON periods while brain temperatures are either stable (NT
mice) or decreased (Tg mice) during ON periods. For both long-term EMF
studies in 2) and 3), body temperature always returned back down to
normal levels during OFF periods.
The present work extends our aforementioned initial
findings by performing two separate temperature-monitoring studies in
order to evaluated sub-chronic (12 days) and long-term (6 weeks) effects
of daily EMF treatment on both body and brain temperature measurements
in very old AD mice and normal mice. During multiple temperature
measurements taken over a 6-week period in very old mice that had been
behaviorally tested, small (but significant) increases of around 0.5°C
in body temperature were evident in both Tg and normal mice. This small
increase of <1°C in body temperature during ON periods of long-term
EMF treatment is very consistent with that seen in our prior studies [4], [5].
Despite these small, but significant increases in body temperature
during ON periods, brain temperature for Tg and normal mice remained
stable or was only elevated 0.3–0.4°C through 6 weeks of exposure – far
below what would be needed to incur brain/physiologic damage [32]. Thus, the EMF-induced cognitive benefits in mice that we have reported both in our prior report [4]
and presently are apparently due to non-thermal brain mechanisms –
several of which we have already identified (see last section).
In the sub-chronic (12-day) EMF treatment study, very old
APPsw+PS1 (Tg) mice exhibited no change in body or brain temperature
during ON periods at both 5 days and 12 days into EMF treatment. This is
somewhat in contrast to the long-term study, wherein a significant
increase in body temperature during ON periods was already present at 1
week into EMF treatment, although no change in brain temperature
occurred (same as in sub-chronic study). The only difference between the
two studies, other than temperature recording points, was that double
Tg (APPsw+PS1) mice were used in the sub-chronic study, which would have
even greater brain A? burdens than the APPsw mice used in the long-term
study.
At 2 months into daily EMF treatment in the long-term
study, Tg mice (but not normal mice) exhibited a significant 13%
decrease in rCBF during ON vs. OFF periods. This EMF-induced reduction
in rCBF was even greater (?25%) compared to control Tg mice during sham
ON periods. The difference between Tg and NT mice is brain production
and aggregation/deposition of A? in Tg mice. Earlier studies have
provided evidence that EMF treatment increases neuronal activity [16], [19], [21], [33], [34].
As mentioned previously, our very recent findings show that long-term
EMF treatment does indeed increase neuronal activity in Tg and NT mice,
irrespective of genotype [20]. Since intraneuronal A? is synaptically released in greater amounts during increased neuronal activity [35],
there is presumably greater efflux of this soluble/monomeric A? out of
the brain and into the blood during EMF exposure. Inasmuch as vascular
A? is a well-known constrictor of smooth muscle in resistance vessels
(e.g., arterioles), we believe that this enhanced presence of
cerebrovascular A? due to EMF exposure induces cerebral vasoconstriction
and the resulting decreases in rCBF that were observed in Tg mice.
Also in the long-term (2 months) study, rCBF was reduced
even during OFF periods in both Tg and normal mice being given EMF
treatment. Indeed, when both genotypes were combined to investigate main
effects of EMF treatment, rCBF was significantly decreased during both
ON (?23%) and OFF (?16%) periods. Clearly, some non-specific EMF
mechanism is reducing rCBF during OFF periods in both Tg and NT mice.
For example, this may be a continuing auto-regulatory response to limit
brain heating due to the slight body hyperthermia present during ON
periods. Along this line, body hyperthermia (such as that induced by
exercise) has been shown to decrease cerebral blood flow in humans by
18% [36], [37].
The reductions in rCBF presently observed during both ON and OFF
periods of long-term EMF treatment in Tg and NT mice are consistent with
several human PET studies reporting that rCBF is reduced during single
exposure EMF treatment [18], [38].
Similar to rCBF results from the long-term EMF study,
evaluation of rCBF at 12 days into EMF treatment for APPsw+PS1 (Tg) mice
in the sub-chronic study revealed a near significant 19% decrease in
rCBF during ON periods. Indeed, 4 of 5 Tg-treated mice exhibited rCBF
decreases of 7–46%. Since there was no increase in body temperature
during ON periods, there was no need for themoregulatory mechanisms to
limit CBF to the brain. However, it is likely that during ON periods,
elevated vascular A? caused a modest vasoconstriction in the brain and
the ensuing decrease in CBF that was observed.
Mechanisms of long-term EMF action and evidence for EMF safety
Results from the present study, in concert with those from our prior three studies [4], [5], [20],
are beginning to provide critical mechanistic insight into the ability
of long-term, high frequency EMF exposure to benefit cognitive function
in normal and AD mice. Fig. 7
summarizes our current understanding of those mechanisms, which are
relevant to human long-term EMF exposure as well. Although this summary
diagram is the result of long-term studies involving GMS-modulated and
pulsed EMF treatment at specific parameters (918 MHz, 0.25–1.05 W/kg),
different combinations of frequency/SAR levels will likely provide more
robust mechanistic actions within this circuit and expand it, resulting
in greater or more rapid cognitive benefit.
Summary diagram depicting both confirmed and proposed
mechanisms of long-term EMF action in normal mice and Alzheimer’s
transgenic (Tg) mice.
As depicted in Fig. 7
for AD mice, high frequency EMF treatment would appear to exert two
complementary actions that ultimately result in enhanced A?
removal/efflux from the brain: 1) prevention and reversal of brain A?
aggregation/deposition [4], and 2) increased neuronal/EEG activity [16], [20], [19]–[21], [33], [34].
EMF treatment’s suppression of extracellular and intracellular A?
aggregation, combined with enhanced synaptic release of intra-neuronal
A? during increased neuronal activity [35],
result in soluble monomergic forms of free A? in the brain parenchyma –
A? forms that can be readily transported across the blood-brain barrier
[39] and into the blood for eventual degradation. As previously mentioned, soluble/monomeric A? is a powerful vasoconstrictor [40], [41],
which is probably key to the substantial decrease in rCBF present
during EMF ON periods in Tg mice. Since A? is not a factor for EMF
effects in normal mice, normal mice incur a less robust, generalized
decrease in CBF through some as yet unidentified mechanism (e.g.,
compensatory to EMF-induced increases in body temperature). Similarly,
long-term EMF treatment to Tg mice induces large enhancements in brain
mitochondrial function due to disaggregation of mitochondrial-impairing
oligomeric A? in neurons, with a lesser enhancement present in normal
mice due to an as yet unidentified mechanism [5].
All of the aforementioned EMF mechanisms occur in mice with only a slight (or no) increase in brain temperature [5] and no increase in brain oxidative stress/damage [4].
Indeed, examination of both peripheral and brain tissues from animals
given daily EMF treatment for over 8 months has revealed no tissue
abnormalities [4],
including no increase in DNA damage to blood cells from these same
animals [Cao et al., unpublished observations]. The lack of deleterious
brain and peripheral effects in such long-term EMF studies, in
combination with recent epidemiologic human studies also reporting no
consistent evidence for EMF-induced health problems [10]–[12],
underscores the mounting evidence that high frequency EMF treatment
over long periods of time, could be a safe and novel disease-modifying
therapeutic against AD.
Materials and Methods
Ethics statement
All animal procedures were performed in AAALAC-certified
facilities under protocol #R3258, approved by the University of South
Florida Institutional Animal Care and Use Committee.
Animals
For both studies of this work, a total of 41 aged mice
derived from the Florida Alzheimer’s Disease Research Center’s colony
were included. Each mouse had a mixed background of 56.25% C57, 12.5%
B6, 18.75% SJL, and 12.5% Swiss-Webster. All mice were derived from a
cross between heterozygous mice carrying the mutant APPK670N, M671L gene
(APPsw) with heterozygous PS1 (Tg line 6.2) mice, which provided
offspring consisting of APPsw+PS1, APPsw, PS1, and NT genotypes. After
weaning and genotyping of these F10 and F11 generation offspring, APPsw
and NT mice were selected for a long-term behavioral study (Study I),
while APPsw+PS1 mice were selected for a follow-up, shorter duration
temperature/cerebral blood flow-monitoring study (Study II) – aged APPsw
were not available for the ensuing Study II. All mice were housed
individually after genotyping, maintained on a 12-hour dark and 12-hour
light cycle with ad libitum access to rodent chow and water.
Study I: Two-month EMF Treatment Study
At 21–26 months of age, APPsw Tg mice (n=17) and NT littermates (n=10)
were first evaluated in RAWM task of working memory (see Behavioral
testing protocols) to establish baseline cognitive performance for both
genotypes prior to EMF treatment. Based on pretreatment performance in
the RAWM task, Tg and NT groups were each divided into two
performance-balanced sub-groups as follows: Tg controls (n=8), Tg+EMF (n=9), NT controls (n=5), and NT+EMF (n=5).
Tg and NT mice to be exposed to EMFs had their cages placed within a
large Faraday cage, which contained an EMF generator antenna that
provided two 2-hour periods of EMF treatment per day (see EMF treatment
protocol). At 22–27 months of age (one month into EMF treatment), all
mice were started on a one-month series of behavioral tasks. EMF
treatment was continued during the one-month behavioral testing period,
with all testing performed during “OFF” periods in between the two daily
EMF treatments. Body and brain temperature measurements were performed
just prior to initiation of EMF treatment and at 1, 3, and 6 weeks into
EMF treatment (see Body/brain temperature determinations). Doppler
recordings of rCBF were taken at 2 months in EMF treatment (see rCBF
determinations). On the day following rCBF measurements, animals were
euthanized at 23–28 months of age, during which a blood sample was taken
and brains were perfused with isotonic phosphate-buffered saline (PBS).
The caudal brain was then paraffin-embedded and processed for A?
immunohistochemical staining, while the remaining forebrain was
sagitally bisected and dissected into hippocampus and cortical areas
that were quick-frozen for neurochemical analyses. Plasma was analyzed
for both A?1–40 and A?1–42.
Study II: 12-day EMF Treatment Study
At 22 months of age, 11 APPsw+PS1 Tg mice were divided
into two groups of 5–6 mice each. One group was placed into the faraday
cage for two daily EMF exposures exactly as for mice in the 2-month EMF
Treatment Study (see EMF treatment protocol). The other group served as
EMF controls, housed in a completely separate room with an identical
environment without EMF treatment. Body and brain temperature recordings
were taken from all mice just prior to onset of the first EMF
treatment, as well as on the 5th day and 12th day into EMF treatment. Concurrent with temperature recording on Day 12, cerebral blood flow measurements were also taken.
EMF treatment protocol
Tg and NT mice given EMF treatment were individually housed in cages
within a large Faraday cage, which also housed the antenna of an EMF
generator providing two 2-hour periods of electromagnetic waves per day
(early morning and late afternoon). Each EMF exposure was at 918 MHz
frequency, involved modulation with Gaussian minimal-shift keying (GMSK)
signal, and was pulsed/non-continuous with carrier bursts repeated
every 4.6 ms, giving a pulse repetition rate of 217 Hz. The electrical
field strength varied between 17 and 35 V/m. This resulted in calculated
SAR levels that varied between 0.25 and 1.05 W/kg. Calculated SAR
values have been shown to correspond closely with measured SAR values [42]. SAR was calculated from the below equation, with ? (0.88 sec/m) and ? (1030 kg/m3) values attained from Nightingale et al. [43]:
?=mean electrical conductivity of mouse brain tissue.
?=mass density of mouse brain.
E=electrical field strength.
For the 2-month and 12-day periods of EMF treatment given
to mice in Study’s I and II, respectively, cages of individually-housed
mice were maintained within the Faraday cage (1.2×1.2×1.2 m3)
and arranged in a circular pattern. Each cage was approximately 26 cm
from a centrally located EMF-emitting antenna. The antenna was connected
to a Hewlett–Packard ESG D4000A digital signal generator (Houston, TX,
USA) set to automatically provide two 2-hour exposures per day. With a
12-hour light ON/OFF cycle, the 2-hour daily exposures occurred in early
morning and late afternoon of the lights on period. Sham-treated
control Tg and NT mice were located in a completely separate room, with
identical room temperature as in the EMF exposure room and with animals
individually housed in cages that were arranged in the same circular
pattern.
Behavioral Testing Protocols
Prior to EMF treatment, all mice in Study I were
behaviorally tested for 10 days in RAWM task of working memory to
determine baseline cognitive performance in this task. Daily EMF
treatment was then started, with behavioral testing initiated at one
month into EMF treatment and occurring between early morning and late
afternoon EMF treatments. One-day tasks of sensorimotor function were
initially carried out (open field activity, balance beam, string
agility), followed by a one-day Y-maze task (locomotor activity,
spontaneous alternation), then RAWM Test I (4 days), circular platform
performance (4 days), RAWM Test II (4 days), then finally the visual
cliff test of visual acuity (1 day). Although the methodologies for all
of these tasks have been previous described and are well established [44]–[46], a brief description of each task is provided below:
Open field activity
Open field activity was used to measure exploratory
behavior and general activity. Mice were individually placed into an
open black box 81×81 cm with 28.5-cm high walls. This area was divided
by white lines into 16 squares measuring 20×20 cm. Lines crossed by each
mouse over a 5-minute period were counted.
Balance beam
Balance beam was used to measure balance and general motor
function. The mice were placed on a 1.1-cm wide beam, suspended above a
padded surface by two identical columns. Attached at each end of the
beam was an escape platform. Mice were placed on the beam in a
perpendicular orientation and were monitored for a maximum of 60 secs.
The time spent by each mouse on the beam before falling or reaching one
of the platforms was recorded for each of three successive trials. If a
mouse reached one of the escape platforms, a time of 60 secs was
assigned for that trial. The average of all three trials was utilized.
String agility
String agility was used to assess forepaw grip capacity
and agility. Mice were placed in the center of a taut cotton string
suspended above a padded surface between the same two columns as in the
balance beam task. Mice were allowed to grip the string with only their
forepaws and then released for a maximum of 60 secs. A rating system,
ranging between 0 and 5, was employed to assess string agility for a
single 60-sec trial.
Y-maze spontaneous alternation
Y-maze spontaneous alternation was used to measure general
activity and basic mnemonic function. Mice were allowed 5 minute to
explore a black Y-maze with three arms. The number and sequence of arm
choices were recorded. General activity was measured as the total number
of arm entries, while basic mnemonic function was measured as a
percentage of spontaneous alternation (the ratio of arm choices
different from the previous two choices divided by the total number of
entries).
Circular platform
Circular platform was used to measure spatial/reference
learning and memory. Mice were placed on a 69-cm circular platform with
16 equally spaced holes on the periphery of the platform. Underneath
only one of the 16 holes was a box filled with bedding to allow the
mouse to escape from aversive stimuli (e.g. two 150-W flood lamps hung
76 cm above the platform and one high-speed fan 15 cm above the
platform). Each mouse was administered one 5-minute trial per day to
explore the area. For the single trial administered on each of four test
days, mice were placed in the center of the platform facing away from
their escape hole (which differed for each mouse). Escape latency was
measured (maximum of 300 secs) each day. Data was statistically analyzed
in two 2-day blocks.
RAWA
RAWA task of spatial working memory involved use of an
aluminum insert, placed into a 100 cm circular pool to create 6 radially
distributed swim arms emanating from a central circular swim area. An
assortment of 2-D and 3-D visual cues surrounded the pool. The latency
and number of errors prior to locating which one of the 6 swim arms
contained a submerged escape platform (9 cm diameter) was determined for
5 trials/day over 10 days of pre-treatment testing. There was a
30-minute time delay between the 4th trial and the 5th
trial (T5; memory retention trial). The platform location was changed
daily to a different arm, with different start arms for each of the 5
trials semi-randomly selected from the remaining 5 swim arms. During
each trial (60-sec maximum), the mouse was returned to that trial’s
start arm upon swimming into an incorrect arm and the number of seconds
required to locate the submerged platform was recorded. If the mouse did
not find the platform within a 60-sec trial, it was guided to the
platform for the 30-sec stay. The latency and number of errors during
Trial 1 (T1) are chance performance since the animal does not know where
the submerged platform is for the first trial of any given day. Latency
and errors during the last trial (Trial 5; T5) of any given day are
considered indices of working memory and are temporally similar to the
standard registration/recall testing of specific items used clinically
in evaluating AD patients. Data for T1 and T5 were statistically
analyzed in two-day blocks, as well as overall, for the 10-day of
pretreatment RAWM testing, the 4-day of RAWM Test I, and the 4-day of
RAWM Test II. Because the final block of testing is most representative
of true working memory potential in this task, results from the last
2-day block of testing are presented for all three RAWM test periods.
Visual Cliff
Visual Cliff was utilized on the last day of behavioral
testing to evaluate vision/depth perception. A wooden box has two
horizontal surfaces, both of which have the same bold pattern, but one
surface of which is 10–12 inches below the other. A sheet of clear
Plexiglass is placed across the entire horizontal surface, providing the
visual appearance of a cliff. An animal with poor vision/depth
perception cannot detect the “cliff” and will move without hesitation
across the cliff, resulting in a score of “1?. An animal with good
vision will pause/hesitate at the cliff before crossing it and is scored
a “2?.
Body/brain temperature determinations
For body/brain temperature determinations of mice in both
Studies I and II, body temperature was taken via rectal probe and brain
temperature via temporalis muscle probe. Prior studies have demonstrated
that temporalis muscle temperature very accurately reflects brain
temperature in rodents [47], [48].
Temperature determinations during EMF treatment (ON periods) were taken
near the end of the morning EMF treatment, while temperature
determinations during OFF periods were in early afternoon (mid-way
between the two daily EMF treatments). Each measurement only took a
couple of minutes for each mouse.
rCBF determinations
In cerebral cortex, rCBF measurements during the ON period
were taken near the end of either the morning EMF treatment session
(Study I) or the afternoon treatment session (Study II). rCBF
measurements during the OFF period were taken in early afternoon,
mid-way between both EMF treatment sessions. For each measurement,
anesthetized (equithesin 300 mg/kg i.p.) animals underwent rCBF
measurement using laser Doppler flowmetry (PF-5010, Periflux system,
Järfälla, Sweden) with relative flow values expressed as perfusion units
[49], [50].
All rCBF measurements were conducted with the animal fixed in a Kopf
stereotaxic apparatus, with the probe placed at the level of the dura
directly above a small skull opening. Using a micromanipulator, two
probes (probe 411, 0.45 mm in diameter) were positioned to cortical
coordinates of 1.3 mm posterior to the bregma and 2.8 mm to each side of
midline on the intact skull, being careful to avoid pial vessels after
reflection of the skin overlying the calvarium. Because mouse skull and
subarachnoid space are very thin, transcranial measurements of rCBF are
consistent with craniectomy measurements [51].
The rCBF of both hemispheres were continuously measured for 15 minutes
and averaged for each determination. All rCBF data was continuously
stored in a computer and analyzed using the Perimed data acquisition and
analysis system.
A immunohistochemistry and image analysis
At the level of the posterior hippocampus (bregma 2.92 mm
to 3.64 mm), five 5 µm sections (150 µm apart) were taken from each
mouse brain using a sliding microtome (REM-710, Yamato Kohki Industrial,
Asaka, Saitama, Japan). Immunohistochemical staining was performed
following the manufacturer’s protocol using aVectastainABC Elite
kit (Vector Laboratories, Burlingame, CA) coupled with the
diaminobenzidine reaction, except that the biothinylated secondary
antibody step was omitted. Used as the primary antibody was a
biothinylated human A? monoclonal antibody (clone 4G8; 1200,
Covance Research Products, Emeryville, CA). Brain sections were treated
with 70% formic acid prior to the pre-blocking step. 0.1 M PBS (pH 7.4)
or normal mouse serum (isotype control) was used instead of primary
antibody or ABC reagent as a negative control. Quantitative image
analysis was done based on previously validated method [52].
Images were acquired using an Olympus BX60 microscope with an attached
digital camera system (DP-70, Olympus, Tokyo, Japan), and the digital
image was routed into a Windows PC for quantitative analysis using
SimplePCI software (Hamamatsu Photonics, Hamamatsu, Shizuoka, Japan).
Images of five 5-µm sections (150 µm apart) through both anatomic
regions of interest (hippocampus and entorhinal cortex) were captured
from each animal, and a threshold optical density was obtained that
discriminated staining from background. Each region of interest was
manually edited to eliminate artifacts, with A? burden data reported as
percentage of immune-labeled area captured (positive pixels) relative to
the full area captured (total pixels). Each analysis was done by a
single examiner blinded to sample identities.
Plasma A levels
A 1–40 and 1–42 levels were determined from plasma samples
by using ELISA kits (KHB3482 for 40, KHB3442 for 42, Invitrogen, CA).
Standard and samples were mixed with detection antibody and loaded on
the antibody pre-coated plate as the designated wells. HRP-conjugated
antibody was added after wash, and substrates were added for
colorimetric reaction, which was then stopped with sulfuric acid.
Optical density was obtained and concentrations were calculated
according a standard curve.
Statistical Analysis
Data analysis of physiologic and neurohistologic
measurements, as well as all one-day behavioral measures, were performed
using ANOVA followed by Fisher’s LSD post hoc test. For the
multiple-day behavioral tasks (RAWM and circular platform), initial
ANOVA analysis of 2-day blocks and overall were followed by analysis of post hoc
pair-by-pair differences between groups via the Fisher LSD test. For
temperature and blood flow measurements within the same animal, paired t-tests
were employed. All data are presented as mean ± SEM, with significant
group differences being designated by p<0.05 or higher level of
significance.
Acknowledgments
We gratefully acknowledge the graphic skills of Loren Glover for figure preparations.
Footnotes
Competing Interests: Co-author Dr. Cesar
Borlongan is a PLoS ONE Editorial Board member. Co-author Richard
Gonzalez is founder and CEO of a small electronics company, SAI of
Florida, Redington Beach, Florida 33708. This does not alter the
authors’ adherence to all the PLoS ONE policies on sharing data and
materials.
Funding: This work was supported by funds
from the NIA-designated Florida Alzheimer’s Disease Research Center
(AG025711) to G.A., the USF/Byrd Alzheimer’s Institute to G.A., and a
USF Interdisciplinary Research Development Grant to G.A. and C.V.B. N.T.
is a recipient of the 2011 Alzheimer’s Drug Discovery Foundation Young
Investigator Scholarship. The funders had no role in study design, data
collection and analysis, decision to publish, or preparation of the
manuscript.
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Altern Ther Health Med. 2011 Nov-Dec;17(6):22-8.
Long-term Effects of Bio-electromagnetic-energyregulation Therapy on Fatigue in Patients With Multiple Sclerosis.
Ziemssen T, Piatkowski J, Haase R.
Abstract
Background Electromagnetic-field therapy has beneficial short-term
effects in multiple sclerosis (MS) patients with major fatigue, but
long-term data are lacking.
Primary Study Objectives To evaluate the long-term effects of a
specific electromagnetic therapy device (Bio-Electromagnetic-
Energy-Regulation [BEMER]) on MS-related fatigue, we designed a
crossover control of a previously performed randomized controlled trial
and a long-term open-label follow-up trial.
Design and Setting: Crossover and open-label follow-up trials at a
single neurological outpatient center. Participants Patients with
relapsing-remitting MS who had major fatigue (N = 37 patients).
Intervention After a previous randomized controlled trial (exposure to
low-frequency pulsed magnetic fields for 8 min twice daily or to placebo
treatment for 12 wk), a crossover from control to treatment for another
12 weeks, followed by an openlabel follow-up trial to 3 years, were
done.
Primary Outcome Measures The outcome criteria were the Modified
Fatigue Impact Scale (MFIS), Fatigue Severity Scale (FSS), German long
version of the Center for Epidemiologic Studies Depression Scale
(CES-D), Multiple Sclerosis Functional Scale (MSFC), and Expanded
Disability Status Scale (EDSS). Results Patients previously on placebo
during the randomized controlled trial experienced significant
reductions in fatigue after crossing over to treatment. The MFIS and FSS
scores were significantly lower in the open-label group than in the
control subjects after follow-up. Participation in the open-label
treatment was the strongest predictor of low fatigue outcome after
followup. Electromagnetic-field therapy was well tolerated.
Conclusions In this long-term study, a beneficial effect of long-term
BEMER therapy on MS fatigue was demonstrated. Electromagnetic-field
therapy may be a useful therapeutic modality in MS patients with severe
fatigue.
J Recept Signal Transduct Res. 2010 Aug;30(4):214-26.
Electromagnetic fields: mechanism, cell signaling, other bioprocesses, toxicity, radicals, antioxidants and beneficial effects.
Kovacic P, Somanathan R.
Department of Chemistry, San Diego State University, San Diego, California, USA. pkovacic@sundown.sdsu.edu
Abstract
Electromagnetic fields (EMFs) played a role in the initiation of
living systems, as well as subsequent evolution. The more recent
literature on electrochemistry is documented, as well as magnetism. The
large numbers of reports on interaction with living systems and the
consequences are presented. An important aspect is involvement with cell
signaling and resultant effects in which numerous signaling pathways
participate. Much research has been devoted to the influence of man-made
EMFs, e.g., from cell phones and electrical lines, on human health. The
degree of seriousness is unresolved at present. The relationship of
EMFs to reactive oxygen species (ROS) and oxidative stress (OS) is
discussed. There is evidence that indicates a relationship involving
EMFs, ROS, and OS with toxic effects. Various articles deal with the
beneficial aspects of antioxidants (AOs) in countering the harmful
influence from ROS-OS associated with EMFs. EMFs are useful in medicine,
as indicated by healing bone fractures. Beneficial effects are recorded
from electrical treatment of patients with Parkinson’s disease,
depression, and cancer.
J Altern Complement Med. 2009 May;15(5):507-11.
Effect of BEMER magnetic field therapy on the level of fatigue in
patients with multiple sclerosis: a randomized, double-blind controlled
trial.
Piatkowski J, Kern S, Ziemssen T.
Source
Neurological Outpatient Center Reichenbachstrasse, Dresden, Germany.
AbstractOBJECTIVES:
Electromagnetic field therapy has been reported to be beneficial in
patients with multiple sclerosis (MS) with significant fatigue. This
study was designed to evaluate the long-term effects of
Bio-Electro-Magnetic-Energy-Regulation (BEMER) on MS-related fatigue.
DESIGN:
This was a monocenter, patient- and rater-blinded, placebo-controlled trial.
PATIENTS:
There were 37 relapsing-remitting patients with MS with significant fatigue in the study.
INTERVENTION:
The intervention consisted of BEMER magnetic field treatment for 8 minutes twice daily in comparison to placebo for 12 weeks.
OUTCOME MEASURES:
The primary outcome criterion was change in the Modified Fatigue
Impact Scale (MFIS) between baseline and 12 weeks. The secondary outcome
criteria were changes of the Fatigue Severity Scale (FSS), a general
depression scale-long version (ADS-L), Multiple Sclerosis Functional
Scale (MSFC), and the Expanded Disability Status Scale (EDSS).
RESULTS:
There was evidence of a significant difference of MFIS value (primary
outcome criterion) after 12 weeks in favor of the verum group (26.84
versus 36.67; p = 0.024). In addition, FSS values were significantly
lower in the verum group after 12 weeks (3.5 versus 4.7; p = 0.016).
After 6 weeks’ follow-up, verum and placebo groups did not differ in
experienced fatigue (MFIS, FSS). Regarding the subscales of the MFIS,
there was a significant decrease in physical (p = 0.018) and cognitive
(p = 0.041), but not in psychologic subscales only in the verum group
regarding the timepoints baseline and 12 weeks. BEMER therapy was well
tolerated.
DISCUSSION:
In this pilot study, we were able to demonstrate a beneficial effect
of BEMER intervention on MS fatigue. As this was only a pilot study,
trials with more patients and longer duration are mandatory to describe
long-term effects.
Biolectromagn Biol Med. 2007;26(4):305-9.
The autistic syndrome and endogenous ion cyclotron resonance: state of the art.
Crescentini F.
Department of Bioelectromagnetic Research, I.R.P. L’Aquila, Pescara, Italy.
The autistic syndrome is a multigenic disease whose expression is
different according to the level of involvement of different structures
in the central nervous system. The pathogenesis is unknown. No
completely effective medical therapy has yet been demonstrated.
Accepting the request of the families of eight autistic children in
Lomazzo, Milan and Naples, we used ion cyclotron resonance (Seqex(R)
therapy) therapeutic support after many other therapies had been already
carried out on these patients. After regimens consisting of 20-30
treatments with ICR, improvements were noted in all cases.
Int J Neurosci. 2006 Jul;116(7):775-826.
Serotonergic mechanisms in amyotrophic lateral sclerosis.
Sandyk R.
The Carrick Institute for Clinical Ergonomics Rehabilitation, and
Applied Neurosciences, School of Engineering Technologies State
University of New York at Farmingdale, Farmingdale, New York 11735, USA.
rsandyk@optonline.net
Serotonin (5-HT) has been intimately linked with global regulation of
motor behavior, local control of motoneuron excitability, functional
recovery of spinal motoneurons as well as neuronal maturation and aging.
Selective degeneration of motoneurons is the pathological hallmark of
amyotrophic lateral sclerosis (ALS). Motoneurons that are preferentially
affected in ALS are also densely innervated by 5-HT neurons (e.g.,
trigeminal, facial, ambiguus, and hypoglossal brainstem nuclei as well
as ventral horn and motor cortex). Conversely, motoneuron groups that
appear more resistant to the process of neurodegeneration in ALS (e.g.,
oculomotor, trochlear, and abducens nuclei) as well as the cerebellum
receive only sparse 5-HT input. The glutamate excitotoxicity theory
maintains that in ALS degeneration of motoneurons is caused by excessive
glutamate neurotransmission, which is neurotoxic. Because of its
facilitatory effects on glutaminergic motoneuron excitation, 5-HT may be
pivotal to the pathogenesis and therapy of ALS. 5-HT levels as well as
the concentrations 5-hydroxyindole acetic acid (5-HIAA), the major
metabolite of 5-HT, are reduced in postmortem spinal cord tissue of ALS
patients indicating decreased 5-HT release. Furthermore, cerebrospinal
fluid levels of tryptophan, a precursor of 5-HT, are decreased in
patients with ALS and plasma concentrations of tryptophan are also
decreased with the lowest levels found in the most severely affected
patients. In ALS progressive degeneration of 5-HT neurons would result
in a compensatory increase in glutamate excitation of motoneurons.
Additionally, because 5-HT, acting through presynaptic 5-HT1B receptors,
inhibits glutamatergic synaptic transmission, lowered 5-HT activity
would lead to increased synaptic glutamate release. Furthermore, 5-HT is
a precursor of melatonin, which inhibits glutamate release and
glutamate-induced neurotoxicity. Thus, progressive degeneration of 5-HT
neurons affecting motoneuron activity constitutes the prime mover of the
disease and its progression and treatment of ALS needs to be focused
primarily on boosting 5-HT functions (e.g., pharmacologically via its
precursors, reuptake inhibitors, selective 5-HT1A receptor
agonists/5-HT2 receptor antagonists, and electrically through
transcranial administration of AC pulsed picotesla electromagnetic
fields) to prevent excessive glutamate activity in the motoneurons. In
fact, 5HT1A and 5HT2 receptor agonists have been shown to prevent
glutamate-induced neurotoxicity in primary cortical cell cultures and
the 5-HT precursor 5-hydroxytryptophan (5-HTP) improved locomotor
function and survival of transgenic SOD1 G93A mice, an animal model of
ALS.
Neuron. 2005 Jan 20;45(2):181-3.
Toward establishing a therapeutic window for rTMS by theta burst stimulation.
Paulus W.
Department of Clinical Neurophysiology, University of Goettingen, D-37075 Goettingen, Germany.
In this issue of Neuron, Huang et al. show that a version of the
classic theta burst stimulation protocol used to induce LTP/LTD in brain
slices can be adapted to a transcranial magnetic stimulation (TMS)
protocol to rapidly produce long lasting (up to an hour), reversible
effects on motor cortex physiology and behavior. These results may have
important implications for the development of clinical applications of
rTMS in the treatment of depression, epilepsy, Parkinson’s, and other
diseases.
Wiad Lek. 2003;56(9-10):434-41.
Application of variable magnetic fields in medicine-15 years experience.
[Article in Polish]
Sieron A, Cieslar G.
Katedra i Klinika Chorob Wewnetrznych, Angiologii i Medycyny Fizykalnej SAM, ul. Batorego 15, 41-902 Bytom. sieron@mediclub.pl
The results of 15-year own experimental and clinical research on
application of variable magnetic fields in medicine were presented. In
experimental studies analgesic effect (related to endogenous opioid
system and nitrogen oxide activity) and regenerative effect of variable
magnetic fields with therapeutical parameters was observed. The
influence of this fields on enzymatic and hormonal activity, free oxygen
radicals, carbohydrates, protein and lipid metabolism, dielectric and
rheological properties of blood as well as behavioural reactions and
activity of central dopamine receptor in experimental animals was
proved. In clinical studies high therapeutic efficacy of magnetotherapy
and magnetostimulation in the treatment of osteoarthrosis, abnormal
ossification, osteoporosis, nasosinusitis, multiple sclerosis,
Parkinson’s disease, spastic paresis, diabetic polyneuropathy and
retinopathy, vegetative neurosis, peptic ulcers, colon irritable and
trophic ulcers was confirmed.
Electric field-induced effects on neuronal cell biology accompanying dielectrophoretic trapping.
Heida T.
University of Twente, Faculty of Electrical Engineering, Mathematics
and Computer Science, Laboratory of Measurement and Instrumentation,
Laboratory of Biomedical Engineering, P.O. Box 217, 7500 AE Enschede,
The Netherlands. t.heida@el.utwente.nl
Abstract
Trapping neuronal cells may aid in the creation of the cultured
neuron probe. The aim of the development of this probe is the creation
of the interface between neuronal cells or tissue in a (human) body and
electrodes that can be used to stimulate nerves in the body by an
external electrical signal in a very selective way. In this way,
functions that were (partially) lost due to nervous system injury or
disease may be restored. First, a direct contact between cultured
neurons and electrodes is created. This is realized using a
microelectrode array (MEA) which can be fabricated using standard
photolithographic and etching methods. Section 1 gives an overview of
the human nervous system, methods for functional recovery focused on the
cultured neuron probe, and the prerequisites for culturing neurons on a
microelectrode array. An important aspect in the selective stimulation
of neuronal cells is the positioning of cells or a small group of cells
on top of each of the electrode sites of the MEA. One of the most
efficient methods for trapping neuronal cells is to make use of
di-electrophoresis (DEP). Dielectrophoretic forces are created when
(polarizable) cells are located in nonuniform electric fields. Depending
on the electrical properties of the cells and the suspending medium,
the DEP force directs the cells towards the regions of high field
strength (positive dielectrophoresis; PDEP) or towards regions of
minimal field intensities (negative dielectrophoresis; NDEP). Since
neurons require a physiological medium with a sufficient concentration
of Na+, the medium conductivity is rather high (~ 1.6 S/m). The result
is that negative dielectrophoretic forces are created over the entire
frequency range. With the use of a planar quadrupole electrode sturcture
negative forces are directed so that in the center of this structure
cell can be collected. The process of trapping cortical rat neurons is
described in Sect. 2 theoretically and experimentally. Medium and cell
properties are frequency-dependent due to relaxation processes, which
have a direct influence on the strength of the dielectrophorectic force.
On the other hand, the nonideal material properties of the gold
electrodes and glass substrate largely determine the electric field
strength created inside the medium. Especially, the electrode-medium
interface results in a significant loss of the imput signal at lower
frequencies (< 1 MHz), and thus a reduction of the electric field
strength inside the medium. Furthermore, due to the high medium
conductivity, the electric field causes Joule heating. Local temperature
rises result in local gradients in fluid density, which induces fluid
flow. The electrode-medium interface and induced fluid flow are
theoretically investigated with the use of modeling techniques such as
finite elements modeling. Experimental and theoretical results agreed
with each other on the occurrence of the effects described in this
section. For the creation of the cultured neuron probe, preservation of
cell viability during the trapping process is a prerequisite. Cell
viability of dielectrophoretically trapped neurons has to be
investigated. The membrane potential induced by the external field plays
a crucial role in preservation of cell viability. The membrane can
effectively be represented by a capaticance in parallel woth a low
conductance; with increasing frequency and /or decreasing field strength
the induced membrane potential decreases. At high induced membrane
potentials ths representation for the membrane is no longer valid. At
this point membrane breakdown occurs and the normally insulating
membrane becomes conductive and permeable. The creation of electropores
has been proposed in literature to be the cause of this high
permeability state. Pores may grow or many small pores may be created
which eventually may lead to membrane rupture, and thus cell death.
Membrane breakdown may be reversible, but a chemical imbalance created
during the high permeability state may still exist after the resealing
of the membrane. This may cause cell death after several hours or even
days after field application. Section 3 gives a detailed description of
membrane breakdown. Since many investigations on electroporation of
lipid bilayers and cell membranes are based on uniform electric fields, a
finite element model is used to investigate induced membrane potentials
in the nonuniform field created by the quadropole electrode structure.
Modeling results are presented in cmbination with the results of
breakdown experiments using four frequencies in the range from 100 kHz
to 1MHz. Radomly positioned neuronals cells were exposed to stepwise
increasing electric field strengths. The field strength at which
membrane rupture occurred gives an indication of the maximum induced
membrane potential. Due to the nonuniformity of the electric field, cell
collapse was expected to be position-dependent. However, at 100 kHz
cells collapsed at a break down level of about 0.4 V, in
contradistinction to findings at higher frequencies where more variation
in breakdown levels were found. Model simulations were able to explain
the experimental results. For examining whether the neuronal cells
trapped by dielectrophoresis were still viable after the trapping
process, the frequency range was divided into two ranges. First, a high
frequency (14 MHz) and a rather low signal amplitude (3 Vpp) were used
to trap cells. At this high frequency the field-induced membrane
potential is small according to the theoretical model, and therefore no
real damage is expected. The experimental analysis included the
investigation of the growth of the neurons, number and length of the
processes (dendrites and axons), and the number of outgrowing (~ viable)
versus nonoutgrowing (~ nonviable) neural cells. The experimental
results agreed with the expectation. The effect of the use of driving
signals with lower frequencies and/or higher amplitudes on cell
viability was investigated using a staining method as described in the
second part of Sect. 4. Survival chances are not directly linked to the
estimated maximum induced membrane potential. The frequency of the dield
plays an important role, decreasing frequency lowering the chance of
survival. A lower frequency limit of 100 kHz is preferable at field
strengths less than 80 k V/m, while with increasing field strength this
limit shifts towards higher frequencies. The theoretical and
experimental results presented in this review form the inception of the
development of new electrode structures for trapping neuronal cells on
top of each of the electrodes of the MEA. New ways to investigate cell
properties and the phenomenon of electroporation using electrokinetic
methods were developed that can be exploited in future research linking
cell biology to technology.
Curr Opin Neurol. 2000 Aug;13(4):397-405.
Recent advances in amotrophic lateral sclerosis.
Al-Chalabi A, Leigh PN.
Department of Neurology, Guy’s King’s and St Thomas’ School of
Medicine and Institute of Psychiatry, De Crespigny Park, London, UK.
The mechanisms by which mutations of the SOD1 gene cause selective
motor neuron death remain uncertain, although interest continues to
focus on the role of peroxynitrite, altered peroxidase activity of
mutant SOD1, changes in intracellular copper homeostasis, protein
aggregation, and changes in the function of glutamate transporters
leading to excitotoxicity. Neurofilaments and peripherin appear to play
some part in motor neuron degeneration, and amyotrophic lateral
sclerosis is occasionally associated with mutations of the neurofilament
heavy chain gene. Linkage to several chromosomal loci has been
established for other forms of familial amyotrophic lateral sclerosis,
but no new genes have been identified. In the clinical field, interest
has been shown in the population incidence and prevalence of amyotrophic
lateral sclerosis and the clinical variants that cause diagnostic
confusion. Transcranial magnetic stimulation has been used to detect
upper motor neuron damage and to explore cortical excitability in
amyotrophic lateral sclerosis, and magnetic resonance imaging including
proton magnetic resonance spectroscopy and diffusion weighted imaging
also provide useful information on the upper motor neuron lesion.
Aspects of care including assisted ventilation, nutrition, and patient
autonomy are addressed, and underlying these themes is the requirement
to measure quality of life with a new disease-specific instrument.
Progress has been made in developing practice parameters. Riluzole
remains the only drug to slow disease progression, although
interventions such as non-invasive ventilation and gastrostomy also
extend survival.
Int J Neurosci. 1994 Jun;76(3-4):185-225.
Alzheimer’s disease: improvement of visual memory and visuoconstructive performance by treatment with picotesla magnetic fields.
Sandyk R.
NeuroCommunication Research Laboratories, Danbury, CT 06811.
Impairments in visual memory and visuoconstructive functions commonly
occur in patients with Alzheimer’s disease (AD). Recently, I reported
that external application of electromagnetic fields (EMF) of extremely
low intensity (in the picotesla range) and of low frequency (in the
range of 5Hz-8Hz) improved visual memory and visuoperceptive functions
in patients with Parkinson’s disease. Since a subgroup of Parkinsonian
patients, specifically those with dementia, have coexisting pathological
and clinical features of AD, I investigated in two AD patients the
effects of these extremely weak EMF on visual memory and
visuoconstructive performance. The Rey-Osterrieth Complex Figure Test as
well as sequential drawings from memory of a house, a bicycle, and a
man were employed to evaluate the effects of EMF on visual memory and
visuoconstructive functions, respectively. In both patients treatment
with EMF resulted in a dramatic improvement in visual memory and
enhancement of visuoconstructive performance which was associated
clinically with improvement in other cognitive functions such as short
term memory, calculations, spatial orientation, judgement and reasoning
as well as level of energy, social interactions, and mood. The report
demonstrates, for the first time, that specific cognitive symptoms of AD
are improved by treatment with EMF of a specific intensity and
frequency. The rapid improvement in cognitive functions in response to
EMF suggests that some of the mental deficits of AD are reversible being
caused by a functional (i.e., synaptic transmission) rather than a
structural (i.e., neuritic plaques) disruption of neuronal communication
in the central nervous system.
Acupunct Electrother Res. 1992;17(2):107-48.
Common factors contributing to intractable pain and medical problems
with insufficient drug intake in areas to be treated, and their
pathogenesis and treatment: Part I. Combined use of medication with
acupuncture, (+) Qi gong energy-stored material, soft laser or
electrical stimulation.
Omura Y, Losco BM, Omura AK, Takeshige C, Hisamitsu T, Shimotsuura Y, Yamamoto S, Ishikawa H, Muteki T, Nakajima H, et al.
Heart Disease Research Foundation, New York.
Most frequently encountered causes of intractable pain and
intractable medical problems, including headache, post-herpetic
neuralgia, tinnitus with hearing difficulty, brachial essential
hypertension, cephalic hypertension and hypotension, arrhythmia, stroke,
osteo-arthritis, Minamata disease, Alzheimer’s disease and
neuromuscular problems, such as Amyotrophic Lateral Sclerosis, and
cancer are often found to be due to co-existence of 1) viral or
bacterial infection, 2) localized microcirculatory disturbances, 3)
localized deposits of heavy metals, such as lead or mercury, in affected
areas of the body, 4) with or without additional harmful environmental
electro-magnetic or electric fields from household electrical devices in
close vicinity, which create microcirculatory disturbances and reduced
acetylcholine. The main reason why medications known to be effective
prove ineffective with intractable medical problems, the authors found,
is that even effective medications often cannot reach these affected
areas in sufficient therapeutic doses, even though the medications can
reach the normal parts of the body and result in side effects when doses
are excessive. These conditions are often difficult to treat or may be
considered incurable in both Western and Oriental medicine. As solutions
to these problems, the authors found some of the following methods can
improve circulation and selectively enhance drug uptake: 1) Acupuncture,
2) Low pulse repetition rate electrical stimulation (1-2
pulses/second), 3) (+) Qi Gong energy, 4) Soft lasers using Ga-As diode
laser or He-Ne gas laser, 5) Certain electro-magnetic fields or rapidly
changing or moving electric or magnetic fields, 6) Heat or moxibustion,
7) Individually selected Calcium Channel Blockers, 8) Individually
selected Oriental herb medicines known to reduce or eliminate
circulatory disturbances. Each method has advantages and limitations and
therefore the individually optimal method has to be selected.
Applications of (+) Qi Gong energy stored paper or cloth every 4 hours,
along with effective medications, were often found to be effective, as
Qigongnized materials can often be used repeatedly, as long as they are
not exposed to rapidly changing electric, magnetic or electro-magnetic
fields. Application of (+) Qi Gong energy-stored paper or cloth, soft
laser or changing electric field for 30-60 seconds on the area above the
medulla oblongata, vertebral arteries or endocrine representation area
at the tail of pancreas reduced or eliminated microcirculatory
disturbances and enhanced drug uptake.(ABSTRACT TRUNCATED AT 400 WORDS)
Int J Neurosci. 1991 Aug;59(4):259-62.
Age-related disruption of circadian rhythms: possible relationship
to memory impairment and implications for therapy with magnetic fields.
Sandyk R, Anninos PA, Tsagas N.
Department of Psychiatry, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY 10461.
Disorganization of circadian rhythms, a hallmark of aging, may be
related causally to the progressive deterioration of memory functions in
senescence and possibly Alzheimer’s disease (AD). In experimental
animals, disruption of circadian rhythms produces retrograde amnesia by
interfering with the circadian organization of memory processes. The
circadian system is known to be synchronized to external 24 h
periodicities of ambient light by a neural pathway extending from the
retina to the suprachiasmatic nucleus (SCN) of the anterior
hypothalamus. There is also evidence that the earth’s magnetic field is a
time cue (“Zeitgeber”) of circadian organization and that shielding of
the ambient magnetic field leads to disorganization of the circadian
rhythms in humans. Since aging is associated with a delay of the
circadian rhythm phase, and since light, which phase advances circadian
rhythms, mimics the effects of magnetic fields on melatonin secretion,
we postulate that application of magnetic fields might improve memory
functions in the elderly as a result of resynchronization of the
circadian rhythms. Moreover, since the circadian rhythm organization is
more severely disrupted in patients with AD, it is possible that
magnetic treatment might prove useful also in improving memory functions
in these patients. If successful, application of magnetic fields might
open new avenues in the management of memory disturbances in the elderly
and possibly in AD.
Zh Nevropatol Psikhiatr Im S S Korsakova. 1990;90(7):108-12.
Regional cerebral angiodystonia in the practice of a neuropathologist and therapist.
[Article in Russian]
Pokalev GM, Raspopina LA.
Altogether 108 patients with regional cerebral angiodystonia were
examined using rheoencephalography, measurements of temporal and venous
pressure and functional tests (nitroglycerin and bicycle ergometry).
Three variants of abnormalities connected with regional cerebral
angiodystonia were distinguished: dysfunction of the inflow, derangement
of the venous outflow, and initial functional venous hypertonia. The
patients were treated with nonmedicamentous therapy (electroanalgesia,
magnetotherapy, iontotherapy).
Rev Neurol. 2004 Feb 16-29;38(4):374-80.
Transcranial magnetic stimulation. Applications in cognitive neuroscience.
[Article in Spanish]
Calvo-Merino B, Haggard P.
Institute of Movement Neuroscience, University College, Londres, UK. b.calvo@ion.ucl.ac.uk
OBJECTIVE: In this review we trace some of the mayor developments in
the use of transcranial magnetic stimulation (TMS) as a technique for
the investigation of cognitive neuroscience. Technical aspects of the
magnetic stimulation are also reviewed.
DEVELOPMENT: Among the many methods now available for studying
activity of the human brain, magnetic stimulation is the only technique
that allows us to interfere actively with human brain function. At the
same time it provides a high degree of spatial and temporal resolution.
Standard TMS applications (central motor conduction time, threshold and
amplitude of motor evoked potentials) allow the evaluation of the motor
conduction in the central nervous system and more complex TMS
applications (paired pulse stimulation, silent period) permit study the
mechanisms of diseases causing changes in the excitability of cortical
areas. These techniques also allow investigation into motor disorder,
epilepsy, cognitive function and psychiatric disorders.
CONCLUSIONS: Transcranial magnetic stimulation applications have an
important place among the investigative tools to study cognitive
functions and neurological and psychiatric disorders. Even so, despite
the many published research and clinical studies, a systematic study
about the possible diagnostic value and role in neurocognitive
rehabilitation of TMS testing need to be realized to offer new
possibilities of future applications.
Neuroreport. 2005 Nov 7;16(16):1849-1852.
Repetitive transcranial magnetic stimulation over the right dorsolateral prefrontal cortex affects strategic decision-making.
Wout MV, Kahn RS, Sanfey AG, Aleman A.
aDepartment of Psychonomics, Helmholtz Research Institute, University
of Utrecht bDepartment of Psychiatry, Rudolf Magnus Institute of
Neuroscience, University Medical Center Utrecht, Utrecht cBCN
NeuroImaging Center, Groningen, The Netherlands dDepartment of
Psychology, University of Arizona, Tucson, Arizona, USA.
Although decision-making is typically seen as a rational process,
emotions play a role in tasks that include unfairness. Recently,
activation in the right dorsolateral prefrontal cortex during offers
experienced as unfair in the Ultimatum Game was suggested to subserve
goal maintenance in this task. This is restricted to correlational
evidence, however, and it remains unclear whether the dorsolateral
prefrontal cortex is crucial for strategic decision-making. The present
study used repetitive transcranial magnetic stimulation in order to
investigate the causal role of the dorsolateral prefrontal cortex in
strategic decision-making in the Ultimatum Game. The results showed that
repetitive transcranial magnetic stimulation over the right
dorsolateral prefrontal cortex resulted in an altered decision-making
strategy compared with sham stimulation. We conclude that the
dorsolateral prefrontal cortex is causally implicated in strategic
decision-making in healthy human study participants.
Brain Stimulation Unit, National Institute of Neurological Disorders
and Stroke, National Institutes of Health, Bethesda, Maryland 20892,
USA.
Electrical direct current (DC) has been applied to the human head
throughout history for various reasons and with claims of behavioral
effects and clinical benefits. This technique has recently been
rediscovered and its effects validated with modern quantitative
techniques and experimental designs. Despite the very weak current used,
DC polarization applied to specific brain areas can alter verbal
fluency, motor learning and perceptual thresholds, and can be used in
conjunction with transcranial magnetic stimulation. Compact and safe,
this old technique seems poised to allow major advances cognitive
science and therapy.
J ECT. 2005 Jun;21(2):88-95.
Transcranial magnetic stimulation in persons younger than the age of 18.
Quintana H.
Department of Psychiatry, Division of Child and Adolescent
Psychiatry, Louisiana State University Health Science Center, School of
Medicine, New Orleans, Louisiana 70112-2822, USA. Hquint@lsuhsc.edu
OBJECTIVES: To review the use of transcranial magnetic stimulation
(single-pulse TMS, paired TMS, and repetitive TMS [rTMS]) in persons
younger than the age of 18 years. I discuss the technical differences,
as well as the diagnostic, therapeutic, and psychiatric uses of TMS/rTMS
in this age group.
METHODS: I evaluated English-language studies from 1993 to August
2004 on nonconvulsive single-pulse, paired, and rTMS that supported a
possible role for the use of TMS in persons younger than 18. Articles
reviewed were retrieved from the MEDLINE database and Clinical
Scientific index.
RESULTS: The 48 studies reviewed involved a total of 1034 children
ages 2 weeks to 18 years; 35 of the studies used single-pulse TMS (980
children), 3 studies used paired TMS (20 children), and 7 studies used
rTMS (34 children). Three studies used both single and rTMS. However,
the number of subjects involved was not reported.
CONCLUSIONS: Single-pulse TMS, paired TMS, and rTMS in persons
younger than 18 has been used to examine the maturation/activity of the
neurons of various central nervous system tracts, plasticity of neurons
in epilepsy, other aspects of epilepsy, multiple sclerosis, myoclonus,
transcallosal inhibition, and motor cortex functioning with no reported
seizure risk. rTMS has been applied to psychiatric disorders such as
ADHD, ADHD with Tourette’s, and depression. Adult studies support an
antidepressant effect from repetitive TMS, but there is only one study
that has been reported on 7 patients that used rTMS to the left dorsal
prefrontal cortex on children/adolescents with depression (5 of the 7
subjects treated responded). Although there are limited studies using
rTMS (in 34 children), these studies did not report significant adverse
effects or seizures. Repetitive TMS safety, ethical, and neurotoxicity
concerns also are discussed.
Biol Psychiatry. 2005 Jun 15;57(12):1597-600.
Transcranial magnetic stimulation-evoked cortical inhibition: a
consistent marker of attention-deficit/hyperactivity disorder scores in
tourette syndrome.
Division of Neurology, Cincinnati Children’s Hospital Medical Center
and University of Cincinnati, OH 45229-3039, USA. d.gilbert@cchmc.org
BACKGROUND: Prior case-control studies using Transcranial Magnetic
Stimulation (TMS) to probe the neural inhibitory circuitry of Attention
Deficit Hyperactivity Disorder (ADHD), Tourette Syndrome (TS), and
Obsessive Compulsive Disorder (OCD), have yielded conflicting results.
Using regression analysis in TS patients with tics, ADHD, and/or OCD
symptoms, all ranging from none to severe, we previously found that
TMS-evoked short interval intracortical inhibition (SICI) correlated
inversely with ADHD scores. We sought to validate this observation.
METHODS: We used regression to estimate the consistency of the
association between ADHD symptom scores and TMS-evoked SICI at two
separate visits in 28 children and adults with TS.
RESULTS: ADHD scores correlated significantly and consistently with
SICI, particularly in patients not taking dopamine receptor blockers
(r=.60 and r=.58). Hyperactivity, not inattention, scores accounted for
ADHD-related variance in SICI.
CONCLUSIONS: SICI reliably reflects the severity of hyperactivity in children and adults with TS.
Child Adolesc Psychiatr Clin N Am. 2005 Jan;14(1):1-19, v.
Emerging brain-based interventions for children and adolescents: overview and clinical perspective.
Hirshberg LM, Chiu S, Frazier JA.
The NeuroDevelopment Center, 260 West Exchange Street, Suite 302,
Providence, RI 02903, USA. lhirshberg@neruodevelopmentcenter.com
Electroencephalogram biofeedback (EBF), repetitive transcranial
magnetic stimulation (rTMS), and vagal nerve stimulation (VNS) are
emerging interventions that attempt to directly impact brain function
through neurostimulation and neurofeedback mechanisms. This article
provides a brief overview of each of these techniques, summarizes the
relevant research findings, and examines the implications of this
research for practice standards based on the guidelines for recommending
evidence based treatments as developed by the American Academy of Child
and Adolescent Psychiatry for attention deficit hyperactivity disorder
(ADHD). EBF meets the “Clinical Guidelines” standard for ADHD, seizure
disorders, anxiety, depression, and traumatic brain injury. VNS meets
this same standard for treatment of refractory epilepsy and meets the
lower “Options” standard for several other disorders. rTMS meets the
standard for “Clinical Guidelines” for bipolar disorder, unipolar
disorder, and schizophrenia. Several conditions are discussed regarding
the use of evidence based thinking related to these emerging
interventions and future directions.
Curr Med Res Opin. 2003;19(2):125-30.
Repetitive transcranial magnetic stimulation (rTMS): new tool, new therapy and new hope for ADHD.
Acosta MT, Leon-Sarmiento FE.
Department of Neurology, Children’s National Medical Center, Washington, DC, USA.
Attention-deficit hyperactivity disorder (ADHD) is the most common
developmental disorder that is associated with environmental and genetic
factors. Neurobiological evidence suggests that
fronto-striatum-cerebellum circuit abnormalities, mainly in the right
hemisphere, are responsible for most of the disturbed sensorimotor
integration; dopamine seems to be the main neurochemical alteration
underlying these morphological abnormalities. Different conventional
treatments have been employed on ADHD; however, repetitive transcranial
magnetic stimulation (rTMS), a new and useful option for the
clinical/research investigation of several neuropsychiatric disorders
involving dopamine circuits, has yet to be considered as a therapeutic
tool and possible drug-free option for ADHD. Here the authors explore
the available evidence that makes this tool a rational therapeutic
possibility for patients with ADHD, calling attention to safety issues,
while highlighting the potentials of such an approach and the new hope
it may bring for patients, parents, researchers and clinicians. The
authors advocate carefully conducted clinical trials to investigate
efficacy, safety, cost-effectiveness and clinical utility of rTMS for
ADHD patients – in comparison to both placebo and standard treatments.
Clin Neurophysiol. 2003 Nov;114(11):2036-42.
Disturbed transcallosally mediated motor inhibition in children with attention deficit hyperactivity disorder (ADHD).
Buchmann J, Wolters A, Haessler F, Bohne S, Nordbeck R, Kunesch E.
Department of Child and Adolescence Neuropsychiatry, Centre of Nerve
Disease, University of Rostock, Gehlsdorfer Strasse 20, 18147 Rostock,
Germany.
OBJECTIVE: The aim of this study was to investigate mechanisms of
motor-cortical excitability and inhibition which may contribute to motor
hyperactivity in children with attention deficit hyperactivity disorder
(ADHD).
METHODS: Using transcranial magnetic stimulation (TMS), involvement
of the motor cortex and the corpus callosum was analysed in 13 children
with ADHD and 13 sex- and age-matched controls. Contralateral silent
period (cSP) and transcallosally mediated ipsilateral silent period
(iSP) were investigated.
RESULTS: Resting motor threshold (RMT), amplitudes of motor evoked
potentials (MEP) and cSP were similar in both groups whereas
iSP-latencies were significantly longer (p<0.05) and their duration
shorter (p<0.01) in the ADHD group. For the ADHD group iSP duration
tended to increase and iSP latency to decrease with age (n.s.).
Conners-Scores did neither correlate with iSP-latencies and -duration
nor with children’s age.
CONCLUSIONS: The shortened duration of iSP in ADHD children could be
explained by an imbalance of inhibitory and excitatory drive on the
neuronal network between cortex layer III-the projection site of
transcallosal motor-cortical fibers-and layer V, the origin of the
pyramidal tract. The longer iSP-latencies might be the result of
defective myelination of fast conducting transcallosal fibers in ADHD.
iSP may be a useful supplementary diagnostic tool to discriminate
between ADHD and normal children.
J Child Neurol. 2001 Dec;16(12):891-4.
Subjective reactions of children to single-pulse transcranial magnetic stimulation.
Garvey MA, Kaczynski KJ, Becker DA, Bartko JJ.
Pediatric Movement Disorders Unit, Pediatrics and Developmental
Neuropsychiatry Branch, National Institute of Mental Health, National
Institutes of Health, Bethesda, MD 20892-1255, USA.
garveym@intra.nimh.nih.gov
Single-pulse transcranial magnetic stimulation is a useful tool to
investigate cortical function in childhood neuropsychiatric disorders.
Magnetic stimulation is associated with a shock-like sensation that is
considered painless in adults. Little is known about how children
perceive the procedure. We used a self-report questionnaire to assess
children’s subjective experience with transcranial magnetic stimulation.
Normal children and children with attention-deficit hyperactivity
disorder (ADHD) underwent transcranial magnetic stimulation in a study
of cortical function in ADHD. Subjects were asked to rate transcranial
magnetic stimulation on a 1 to 10 scale (most disagreeable = 1, most
enjoyable = 10) and to rank it among common childhood events.
Thirty-eight subjects completed transcranial magnetic stimulation; 34
said that they would repeat it. The overall rating for transcranial
magnetic stimulation was 6.13, and transcranial magnetic stimulation was
ranked fourth highest among the common childhood events. These results
suggest that although a few children find transcranial magnetic
stimulation uncomfortable, most consider transcranial magnetic
stimulation painless. Further studies are necessary to confirm these
findings.
Int J Neurosci. 1994 Jun;76(3-4):185-225.
Alzheimer’s disease: improvement of visual memory and
visuoconstructive performance by treatment with picotesla range magnetic
fields.
Sandyk R.
NeuroCommunication Research Laboratories, Danbury, CT 06811.
Impairments in visual memory and visuoconstructive functions commonly
occur in patients with Alzheimer’s disease (AD). Recently, I reported
that external application of electromagnetic fields (EMF) of extremely
low intensity (in the picotesla range) and of low frequency (in the
range of 5Hz-8Hz) improved visual memory and visuoperceptive functions
in patients with Parkinson’s disease. Since a subgroup of Parkinsonian
patients, specifically those with dementia, have coexisting pathological
and clinical features of AD, I investigated in two AD patients the
effects of these extremely weak EMF on visual memory and
visuoconstructive performance. The Rey-Osterrieth Complex Figure Test as
well as sequential drawings from memory of a house, a bicycle, and a
man were employed to evaluate the effects of EMF on visual memory and
visuoconstructive functions, respectively. In both patients treatment
with EMF resulted in a dramatic improvement in visual memory and
enhancement of visuoconstructive performance which was associated
clinically with improvement in other cognitive functions such as short
term memory, calculations, spatial orientation, judgement and reasoning
as well as level of energy, social interactions, and mood. The report
demonstrates, for the first time, that specific cognitive symptoms of AD
are improved by treatment with EMF of a specific intensity and
frequency. The rapid improvement in cognitive functions in response to
EMF suggests that some of the mental deficits of AD are reversible being
caused by a functional (i.e., synaptic transmission) rather than a
structural (i.e., neuritic plaques) disruption of neuronal communication
in the central nervous system.
Int J Neurosci. 1991 Aug;59(4):259-62.
Age-related disruption of circadian rhythms: possible relationship
to memory impairment and implications for therapy with magnetic fields.
Sandyk R, Anninos PA, Tsagas N.
Department of Psychiatry, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY 10461.
Disorganization of circadian rhythms, a hallmark of aging, may be
related causally to the progressive deterioration of memory functions in
senescence and possibly Alzheimer’s disease (AD). In experimental
animals, disruption of circadian rhythms produces retrograde amnesia by
interfering with the circadian organization of memory processes. The
circadian system is known to be synchronized to external 24 h
periodicities of ambient light by a neural pathway extending from the
retina to the suprachiasmatic nucleus (SCN) of the anterior
hypothalamus. There is also evidence that the earth’s magnetic field is a
time cue (“Zeitgeber”) of circadian organization and that shielding of
the ambient magnetic field leads to disorganization of the circadian
rhythms in humans. Since aging is associated with a delay of the
circadian rhythm phase, and since light, which phase advances circadian
rhythms, mimics the effects of magnetic fields on melatonin secretion,
we postulate that application of magnetic fields might improve memory
functions in the elderly as a result of resynchronization of the
circadian rhythms. Moreover, since the circadian rhythm organization is
more severely disrupted in patients with AD, it is possible that
magnetic treatment might prove useful also in improving memory functions
in these patients. If successful, application of magnetic fields might
open new avenues in the management of memory disturbances in the elderly
and possibly in AD.
Clin EEG Neurosci. 2004 Jan;35(1):4-13.
Current status of the utilization of antileptic treatments in mood, anxiety and aggression: drugs and devices.
Barry JJ, Lembke A, Bullock KD.
Department of Psychiatry, Stanford University Medical Center, 401
Quarry Road MC 5723, Stanford, CA 94305, USA. jbarry@leland.stanford.edu
Interventions that have been utilized to control seizures in people
with epilepsy have been employed by the psychiatric community to treat a
variety of disorders. The purpose of this review will be to give an
overview of the most prominent uses of antiepileptic drugs (AEDs) and
devices like the Vagus Nerve Stimulator (VNS) and Transcranial Magnetic
Stimulation (TMS) in the treatment of psychiatric disease states. By
far, the most prevalent use of these interventions is in the treatment
of mood disorders. AEDs have become a mainstay in the effective
treatment of Bipolar Affective Disorder (BAD). The U.S. Food and Drug
Administration has approved the use of valproic acid for acute mania,
and lamotrigine for BAD maintenance therapy. AEDs are also effectively
employed in the treatment of anxiety and aggressive disorders. Finally,
VNS and TMS are emerging as possibly useful tools in the treatment of
more refractory depressive illness.
Am J Psychiatry. 2004 Jan;161(1):93-8.
Low-field magnetic stimulation in bipolar depression using an MRI-based stimulator.
Rohan M, Parow A, Stoll AL, Demopulos C, Friedman S, Dager S, Hennen J, Cohen BM, Renshaw PF.
Brain Imaging Center, McLean Hospital, Belmont, MA 02478, USA. mrohan@mclean.harvard.edu
OBJECTIVE: Anecdotal reports have suggested mood improvement in
patients with bipolar disorder immediately after they underwent an
echo-planar magnetic resonance spectroscopic imaging (EP-MRSI) procedure
that can be performed within clinical MR system limits. This study
evaluated possible mood improvement associated with this procedure.
METHOD: The mood states of subjects in an ongoing EP-MRSI study of
bipolar disorder were assessed by using the Brief Affect Scale, a
structured mood rating scale, immediately before and after an EP-MRSI
session. Sham EP-MRSI was administered to a comparison group of subjects
with bipolar disorder, and actual EP-MRSI was administered to a
comparison group of healthy subjects. The characteristics of the
electric fields generated by the EP-MRSI scan were analyzed.
RESULTS: Mood improvement was reported by 23 of 30 bipolar disorder
subjects who received the actual EP-MRSI examination, by three of 10
bipolar disorder subjects who received sham EP-MRSI, and by four of 14
healthy comparison subjects who received actual EP-MRSI. Significant
differences in mood improvement were found between the bipolar disorder
subjects who received actual EP-MRSI and those who received sham
EP-MRSI, and, among subjects who received actual EP-MRSI, between the
healthy subjects and the bipolar disorder subjects and to a lesser
extent between the unmedicated bipolar disorder subjects and the bipolar
disorder subjects who were taking medication. The electric fields
generated by the EP-MRSI scan were smaller (0.7 V/m) than fields used in
repetitive transcranial magnetic stimulation (rTMS) treatment of
depression (1-500 V/m) and also extended uniformly throughout the head,
unlike the highly nonuniform fields used in rTMS. The EP-MRSI waveform, a
1-kHz train of monophasic trapezoidal gradient pulses, differed from
that used in rTMS.
CONCLUSIONS: These preliminary data suggest that the EP-MRSI scan
induces electric fields that are associated with reported mood
improvement in subjects with bipolar disorder. The findings are similar
to those for rTMS depression treatments, although the waveform used in
EP-MRSI differs from that used in rTMS. Further investigation of the
mechanism of EP-MRSI is warranted.
Psychiatry Res. 2004 Sep 30;128(2):199-202.
Repetitive transcranial magnetic stimulation as an add-on therapy in the treatment of mania: a case series of eight patients.
Saba G, Rocamora JF, Kalalou K, Benadhira R, Plaze M, Lipski H, Januel D.
Unite de recherche clinique, secteur III de Ville Evrard, 5, Rue du Dr Delafontaine, Saint-Denis, 93200 France. urcve@free.fr
The aim of this study is to assess the efficacy of repetitive
transcranial magnetic stimulation (rTMS) as an add-on therapy in the
treatment of manic bipolar patients. Eight patients were enrolled in an
open trial. They received fast rTMS (five trains of 15 s, 80% of the
motor threshold, 10 Hz) over the right dorsolateral prefrontal cortex
(DLPFC). They were evaluated using the Mania Assessment Scale (MAS) and
the Clinical Global Impression (CGI) at baseline and at day 14. All
patients were taking medication during the treatment trial. There was a
significant improvement of manic symptoms at the end of the trial. No
side effects were reported. The results show a significant improvement
of mania when patients are treated with fast rTMS over the right DLPFC.
However, these results have to be interpreted with caution since they
derive from an open case series and all the subjects were taking
psychotropic medication during rTMS treatment. Double-blind controlled
studies with a sham comparison condition should be conducted to
investigate the efficiency of this treatment in manic bipolar disorders.
J Affect Disord. 2004 Mar;78(3):253-7.
Treatment of bipolar mania with right prefrontal rapid transcranial magnetic stimulation.
Michael N, Erfurth A.
Mood Disorders Unit, Department of Psychiatry, University of Muenster, Albert-Schweitzer-Str. 11, 48129 Muenster, Germany.
BACKGROUND: Transcranial magnetic stimulation (TMS) has been
suggested for the treatment of a variety of CNS disorders including
depression and mania.
METHODS: Nine bipolar (I) in-patients diagnosed with mania were
treated with right prefrontal rapid TMS in an open and prospective
study. Eight of nine patients received TMS as add-on treatment to an
insufficient or only partially effective drug therapy.
RESULTS: During the 4 weeks of TMS treatment a sustained reduction of
manic symptoms as measured by the Bech-Rafaelsen mania scale (BRMAS)
was observed in all patients.
LIMITATIONS: Due to the open and add-on design of the study, a clear
causal relationship between TMS treatment and reduction of manic
symptoms cannot be established.
CONCLUSIONS: Our data suggest that right prefrontal rapid TMS is safe
and efficacious in the add-on treatment of bipolar mania showing
laterality opposed to the proposed effect of rapid TMS in depression.
Bipolar Disord. 2003 Feb;5(1):40-7.
Left prefrontal transcranial magnetic stimulation (TMS) treatment of
depression in bipolar affective disorder: a pilot study of acute safety
and efficacy.
Nahas Z, Kozel FA, Li X, Anderson B, George MS.
Brain Stimulation Laboratory, Department of Psychiatry, Medical University of South Carolina, Charleston 29425, USA.
OBJECTIVES: Repetitive transcranial magnetic stimulation (rTMS) has
been shown to improve depressive symptoms. We designed and carried out
the following left prefrontal rTMS study to determine the safety,
feasibility, and potential efficacy of using TMS to treat the depressive
symptoms of bipolar affective disorder (BPAD).
METHODS: We recruited and enrolled 23 depressed BPAD patients (12 BPI
depressed state, nine BPII depressed state, two BPI mixed state).
Patients were randomly assigned to receive either daily left prefrontal
rTMS (5 Hz, 110% motor threshold, 8 sec on, 22 sec off, over 20 min) or
placebo each weekday morning for 2 weeks. Motor threshold and subjective
rating scales were obtained daily, and blinded Hamilton Rating Scale
for Depression (HRSD) and Young Mania Rating Scales (YMRS) were obtained
weekly.
RESULTS: Stimulation was well tolerated with no significant adverse
events and with no induction of mania. We failed to find a statistically
significant difference between the two groups in the number of
antidepressant responders (>50% decline in HRSD or HRSD <10 – 4
active and 4 sham) or the mean HRSD change from baseline over the 2
weeks (t = -0.22, p = 0.83). Active rTMS, compared with sham rTMS,
produced a trend but not statistically significant greater improvement
in daily subjective mood ratings post-treatment (t = 1.58, p = 0.13).
The motor threshold did not significantly change after 2 weeks of active
treatment (t = 1.11, p = 0.28).
CONCLUSIONS: Daily left prefrontal rTMS appears safe in depressed
BPAD subjects, and the risk of inducing mania in BPAD subjects on
medications is small. We failed to find statistically significant TMS
clinical antidepressant effects greater than sham. Further studies are
needed to fully investigate the potential role, if any, of TMS in BPAD
depression.
CNS Drugs. 2002;16(1):47-63.
The Bech-Rafaelsen Mania Scale in clinical trials of therapies for
bipolar disorder: a 20-year review of its use as an outcome measure.
Bech P.
Psychiatric Research Unit, WHO Collaborating Centre for Mental
Health, Frederiksborg General Hospital, Hillerod, Denmark. pebe@fa.dk
Over the last two decades the Bech-Rafaelsen Mania Scale (MAS) has
been used extensively in trials that have assessed the efficacy of
treatments for bipolar disorder. The extent of its use makes it possible
to evaluate the psychometric properties of the scale according to the
principles of internal validity, reliability, and external validity.
Studies of the internal validity of the MAS have demonstrated that the
simple sum of the 11 items of the scale is a sufficient statistic for
the assessment of the severity of manic states. Both factor analysis and
latent structure analysis (the Rasch analysis) have been used to
demonstrate this. The total score of the MAS has been standardised such
that scores below 15 indicate hypomania, scores around 20 indicate
moderate mania, and scores around 28 indicate severe mania. The
inter-observer reliability has been found to be high in a number of
studies conducted in various countries. The MAS has shown an acceptable
external validity, in terms of both sensitivity and responsiveness.
Thus, the MAS was found to be superior to the Clinical Global Impression
scale with regard to responsiveness, and sensitivity has been found to
be adequate, with the MAS able to demonstrate large drug-placebo
differences. Based on pretreatment scores, trials of antimanic therapies
can be classified into: (i) ultrashort (1 week) therapy of severe
mania; (ii) short-term therapy (3 to 8 weeks) of moderate mania; (iii)
short-term therapy of hypomanic or mixed bipolar states; and (iv)
long-term (12 months) therapy of bipolar states. The responsiveness of
MAS is such that the scale has been able to demonstrated that typical
antipsychotics are effective as an ultrashort therapy of severe mania;
that lithium and anticonvulsants are effective in the short-term therapy
of moderate mania; and that atypical antipsychotics, electroconvulsive
therapy (ECT) and transcranial magnetic stimulation seem to have
promising effects in the short-term therapy of moderate mania. In
contrast, the scale has been used to demonstrate that calcium
antagonists (e.g. verapamil) are ineffective in the treatment of mania.
MAS has also been used to add to the literature on the evidence-based
effect of lithium as a short-term therapy for hypomania or mixed bipolar
states and as a long-term therapy of bipolar states.
Altern Ther Health Med. 2006 Sep-Oct;12(5):42-9
Regenerative effects of pulsed magnetic field on injured peripheral nerves.
Mert T,
Gunay I,
Gocmen C,
Kaya M,
Polat S.
Department of Biophysics, University of Cukurova School of Medicine, Adana, Turkey.
Previous studies confirm that pulsed magnetic field (PMF) accelerates
functional recovery after a nerve crush lesion. The contention that PMF
enhances the regeneration is still controversial, however. The
influence of a new PMF application protocol (trained PMF) on nerve
regeneration was studied in a model of crush injury of the sciatic nerve
of rats. To determine if exposure to PMF influences regeneration, we
used electrophysiological recordings and ultrastructural examinations.
After the measurements of conduction velocity, the sucrose-gap method
was used to record compound action potentials (CAPs) from sciatic
nerves. PMF treatment during the 38 days following the crush injury
enhanced the regeneration. Although the axonal ultrastructures were
generally normal, slight to moderate myelin sheath degeneration was
noted at the lesion site. PMF application for 38 days accelerated nerve
conduction velocity, increased CAP amplitude and decreased the time to
peak of the CAP. Furthermore, corrective effects of PMF on. the abnormal
characteristics of sensory nerve fibers were determined. Consequently,
long-periodic trained-PMF may promote both morphological and
electrophysiological properties of the injured nerves. In addition,
corrective effects of PMF on sensory fibers may be considered an
important finding for neuropathic pain therapy.
De Pedro JA, Perez-Caballer AJ, Dominguez J, Collia F, Blanco J, Salvado M.
Department of Orthopaedics, University Hospital of Salamanca, Salamanca, Spain. jpedrom@usal.es
An experimental study was carried out in rats with the purpose of
demonstrating the capacity of pulsed electromagnetic fields (PEMFs) to
stimulate regeneration of the peripheral nervous system (PNS). Wistar
and Brown Norway (BN) rats were used. Direct sciatic nerve anastomoses
were performed after section or allograft interposition. Treatment
groups then received 4 weeks of PEMFs. Control groups received no
stimulation. The evaluation of the results was carried out by
quantitative morphometric analysis, demonstrating a statistically
significant increase in regeneration indices (P < 0.05) in the
stimulated groups (9000 +/- 5000 and 4000 +/- 6000) compared to the
non-stimulated groups (2000 +/- 4000 and 700 +/- 200). An increase of
NAD specific isocitrate dehydrogenase (IDH) activity was found along
with an increase in the activity of acetyl cholinesterase at the motor
plate. The present study might lead to the search for new alternatives
in the stimulation of axonal regenerative processes in the PNS and other
possible clinical applications. 2004 Wiley-Liss, Inc.
Spine. 2003 Dec 15;28(24):2660-6.
Exposure to pulsed magnetic field enhances motor recovery in cats after spinal cord injury.
Neuroscience Research Laboratories, The Clement J. Zablocki VA Medical Center, Milwaukee, WI 53295, USA. mcrowe@mcw.edu
STUDY DESIGN: Animal model study of eight healthy commercial cats was conducted.
OBJECTIVE: To determine whether pulsed electromagnetic field (PMF)
stimulation results in improvement of function after contusive spinal
cord injury in cats. SUMMARY OF
BACKGROUND DATA: PMF stimulation has been shown to enhance nerve
growth, regeneration, and functional recovery of peripheral nerves.
Little research has been performed examining the effects of PMF
stimulation on the central nervous system and no studies of PMF effects
on in vivo spinal cord injury (SCI) models have been reported.
MATERIALS AND METHODS: PMF stimulation was noninvasively applied for
up to 12 weeks to the midthoracic spine of cats with acute contusive
spinal cord injury. The injury was produced using a weight-drop
apparatus. Motor functions were evaluated with the modified Tarlov
assessment scale. Morphologic analyses of the injury sites and
somatosensory-evoked potential measurements were conducted to compare
results between PMF-stimulated and control groups.
RESULTS: There was a significant difference in locomotor recovery
between the PMF-stimulated and control groups. Although not
statistically significant, PMF-stimulated spinal cords demonstrated
greater sparing of peripheral white matter and smaller lesion volumes
compared to controls. Somatosensory-evoked potential measurements
indicated that the PMF-stimulated group had better recovery of preinjury
waveforms than the control group; however, this observation also was
not statistically significant because of the small sample size.
CONCLUSIONS: This preliminary study indicates that pulsed magnetic
fields may have beneficial effects on motor function recovery and lesion
volume size after acute spinal cord injury.
J Neurosci Res. 1999 Jan 15;55(2):230-7.
Electromagnetic fields influence NGF activity and levels following sciatic nerve transection.
Longo FM, Yang T, Hamilton S, Hyde JF, Walker J, Jennes L, Stach R, Sisken BF.
Department of Neurology, UCSF/VAMC, San Francisco, California, USA. LFM@itsa.UCSF.edu
Pulsed electromagnetic fields (PEMF) have been shown to increase the
rate of nerve regeneration. Transient post-transection loss of
target-derived nerve growth factor (NGF) is one mechanism proposed to
signal induction of early nerve regenerative events. We tested the
hypothesis that PEMF alter levels of NGF activity and protein in injured
nerve and/or dorsal root ganglia (DRG) during the first stages of
regeneration (6-72 hr). Rats with a transection injury to the midthigh
portion of the sciatic nerve on one side were exposed to PEMF or sham
control PEMF for 4 hr/day for different time periods. NGF-like activity
was determined in DRG, in 5-mm nerve segments proximal and distal to the
transection site and in a corresponding 5-mm segment of the
contralateral nonoperated nerve. NGF-like activity of coded tissue
samples was measured in a blinded fashion using the chick DRG sensory
neuron bioassay. Overall, PEMF caused a significant decrease in NGF-like
activity in nerve tissue (P < 0.02, repeated measures analysis of
variance, ANOVA) with decreases evident in proximal, distal, and
contralateral nonoperated nerve. Unexpectedly, transection was also
found to cause a significant (P=0.001) 2-fold increase in DRG NGF-like
activity between 6 and 24 hr postinjury in contralateral but not
ipsilateral DRG. PEMF also reduced NGF-like activity in DRG, although
this decrease did not reach statistical significance. Assessment of the
same nerve and DRG samples using ELISA and NGF-specific antibodies
confirmed an overall significant (P < 0.001) decrease in NGF levels
in PEMF-treated nerve tissue, while no decrease was detected in DRG or
in nerve samples harvested from PEMF-treated uninjured rats. These
findings demonstrate that PEMF can affect growth factor activity and
levels, and raise the possibility that PEMF might promote nerve
regeneration by amplifying the early postinjury decline in NGF activity.
Neurosci Behav Physiol. 1998 Sep-Oct;28(5):594-7.
Magnetic and electrical stimulation in the rehabilitative treatment of patients with organic lesions of the nervous system.
Tyshkevich TG, Nikitina VV.
A. L. Polenov Russian Science Research Neurosurgical Institute, St. Petersburg.
Studies were performed on 89 patients with organic lesions of the
nervous system in which the leading clinical symptoms consisted of
paralysis and pareses. Patients received complex treatment, including
pulsed magnetic fields and an electrical stimulation regime producing
multilevel stimulation. A control group of 49 patients with similar
conditions was included, and these patients received only sinusoidal
currents. Combined treatment with magnetic and electrical stimulation
was more effective, as indicated by radiographic and electromyographic
investigations.
Arch Otolaryngol Head Neck Surg. 1998 Apr;124(4):383-9.
Effect of pulsed electromagnetic stimulation on facial nerve regeneration.
Byers JM, Clark KF, Thompson GC.
Department of Otorhinolaryngology, University of Oklahoma Health Sciences Center, Oklahoma City, USA.
OBJECTIVE: To determine if exposure to electromagnetic fields influences regeneration of the transected facial nerve in the rat.
DESIGN AND METHODS: The left facial nerve was transected in the
tympanic section of the fallopian canal in 24 rats randomly assigned to 2
groups. The cut ends of the facial nerve were reapproximated without
sutures within the fallopian canal to maximize the potential for
regeneration. Rats in the experimental group (n= 12) were then exposed
to pulsed electromagnetic stimulation (0.4 millitesla at 120 Hz) for 4
hours per day, 5 days per week, for 8 weeks. Rats in the control group
(n=12) were handled in an identical manner without pulsed
electromagnetic stimulation. Four other rats were given sham operations
in which all surgical procedures were carried out except for the actual
nerve transection. Two of these rats were placed in each group. Nerve
regeneration was evaluated using electroneurography (compound action
potentials), force of whisker and eyelid movements, and voluntary facial
movements before and at 2-week intervals after transection.
Histological evaluation was performed at 10 weeks after transection.
Each dependent variable was analyzed using a 2-way analysis of variance
with 1 between variable (groups) and 1 within repeated measures variable
(days after transection).
RESULTS: Statistical analysis indicated that N1 (the negative
deflection of depolarization phase of the muscle and/or nerve fibers)
area, N1 amplitude, and N1 duration, as well as absolute amplitude of
the compound action potentials, were all significantly greater 2 weeks
after transection in the experimental than in the control group of rats.
The force of eye and whisker movements after electrical stimulation was
statistically greater in the experimental group of rats 4 weeks after
transection. Voluntary eye movements in the experimental group were
significantly better at 5 and 10 weeks, while whisker movements were
better at 3 and 10 weeks. There was no statistical difference between
the 2 groups for any histological variable.
CONCLUSION: Results of this study indicate that pulsed
electromagnetic stimulation enhances early regeneration of the
transected facial nerve in rats.
J Cell Biochem. 1993 Apr;51(4):387-93.
Beneficial effects of electromagnetic fields.
Bassett CA.
Bioelectric Research Center, Columbia University, Riverdale, New York 10463.
Selective control of cell function by applying specifically
configured, weak, time-varying magnetic fields has added a new, exciting
dimension to biology and medicine. Field parameters for therapeutic,
pulsed electromagnetic field (PEMFs) were designed to induce voltages
similar to those produced, normally, during dynamic mechanical
deformation of connective tissues. As a result, a wide variety of
challenging musculoskeletal disorders have been treated successfully
over the past two decades. More than a quarter million patients with
chronically ununited fractures have benefitted, worldwide, from this
surgically non-invasive method, without risk, discomfort, or the high
costs of operative repair. Many of the athermal bioresponses, at the
cellular and subcellular levels, have been identified and found
appropriate to correct or modify the pathologic processes for which
PEMFs have been used. Not only is efficacy supported by these basic
studies but by a number of double-blind trials. As understanding of
mechanisms expands, specific requirements for field energetics are being
defined and the range of treatable ills broadened. These include nerve
regeneration, wound healing, graft behavior, diabetes, and myocardial
and cerebral ischemia (heart attack and stroke), among other conditions.
Preliminary data even suggest possible benefits in controlling
malignancy.
Bioelectromagnetics. 1993;14(4):353-9.
Pretreatment of rats with pulsed electromagnetic field enhances regeneration of the sciatic nerve.
Kanje M, Rusovan A, Sisken B, Lundborg G.
Department of Animal Physiology, University of Lund, Sweden.
Regeneration of the sciatic nerve was studied in rats pretreated in a
pulsed electromagnetic field (PEMF). The rats were exposed between a
pair of Helmholtz coils at a pulse repetition rate of 2 pps at a field
density of 60 or 300 microT. The PEMF treatment was then discontinued.
After an interval of recovery, regeneration of the sciatic nerve was
initiated by a crush lesion. Regeneration of sensory fibers was measured
by the “pinch test” after an additional 3-6 days. A variety of PEMF
pretreatments including 4 h/day for 1-4 days or exposure for 15 min/day
during 2 days resulted in an increased regeneration distance, measured 3
days after the crush lesion. This effect could be demonstrated even
after a 14-day recovery period. In contrast, pretreatment for 4 h/day
for 2 days at 60 microT did not affect the regeneration distance. The
results showed that PEMF pretreatment conditioned the rat sciatic nerve
in a manner similar to that which occurs after a crush lesion, which
indicates that PEMF affects the neuronal cell body. However, the
mechanism of this effect remains obscure.
Brain Res. 1989 Apr 24;485(2):309-16.
Stimulation of rat sciatic nerve regeneration with pulsed electromagnetic fields.
Sisken BF, Kanje M, Lundborg G, Herbst E, Kurtz W.
Center for Biomedical Engineering, University of Kentucky, Lexington 40506.
The effects of pulsed electromagnetic fields (PEMF) on rat sciatic
nerve regeneration after a crush lesion were determined. The rats were
placed between a pair of Helmholtz coils and exposed to PEMF of
frequency 2 Hz and magnetic flux density of 0.3 mT. A 4 h/day treatment
for 3-6 days increased the rate of nerve regeneration by 22%. This
stimulatory effect was independent of the orientation of the coils.
Exposure times of 1 h/day-10 h/day were equally effective in stimulating
nerve regeneration. Rats exposed to PEMF for 4 h/day for 7 days before
crush, followed by 3 days after crush without PEMF, also showed
significantly increased regeneration. This pre-exposure ‘conditioning’
effect suggests that PEMF influences regeneration indirectly.
J Hand Surg [Br]. 1984 Jun;9(2):105-12.
An experimental study of the effects of pulsed electromagnetic field (Diapulse) on nerve repair.
Raji AM.
This study investigates the effects of a pulsed electromagnetic field
(PEMF) (Diapulse) on experimentally divided and sutured common peroneal
nerves in rats. Evidence is presented to show that PEMF accelerates
recovery of use of the injured limb and enhances regeneration of damaged
nerves.
Clin Orthop Relat Res. 1983 Dec;(181):283-90.
Effect of weak, pulsing electromagnetic fields on neural regeneration in the rat.
Ito H, Bassett CA.
The short- and long-term effects of pulsed electromagnetic fields
(PEMFs) on the rate and quality of peripheral nerve regeneration were
studied. High bilateral transections of rat sciatic nerves were
surgically approximated (a 1-mm gap was left) and shielded with a
Silastic sleeve. Animals were exposed to PEMFs for two to 14 weeks after
operation. Three groups of 20 rats each (control rats and rats
undergoing 12- and 24-hour/day PEMF exposure) were killed at two weeks.
Histologically, regenerating axons had penetrated the distal stump
nearly twice as far in the PEMF-exposed animals as in the control
animals. Return of motor function was judged two to 14 weeks after
operation by the load cell-measured, plantar-flexion force produced by
neural stimulation proximal to the transection site. Motor function
returned earlier in experimental rats and to significantly higher load
levels than in control rats. Nerves from animals functioning 12-14 weeks
after operation had less interaxonal collagen, more fiber-containing
axis cylinders, and larger fiber diameters in the PEMF-exposed group
than in the control rats. Histologic and functional data indicate that
PEMFs improve the rate and quality of peripheral nerve regeneration in
the severed rat sciatic nerve by a factor of approximately two.
Paraplegia. 1976 May;14(1):12-20.
Experimental regeneration in peripheral nerves and the spinal cord
in laboratory animals exposed to a pulsed electromagnetic field.
Wilson DH, Jagadeesh P.
Peripheral nerve section and suture was performed in 132 rats.
Postoperatively half the animals were exposed to a pulsed
electromagnetic field each day and half were kept as controls. Nerve
conduction studies, histology and nerve fibre counts all indicated an
increased rate of regeneration in the treated animals. A similar
controlled study of spinal cord regeneration following hemicordotomy in
cats has been started, and preliminary results indicate that when the
animals are sacrificed three months after the hemicordotomy, the pulsed
electromagnetic therapy has induced nerve fibre regeneration across the
region of the scar.
Altern Ther Health Med. 2006 Sep-Oct;12(5):42-9
Regenerative effects of pulsed magnetic field on injured peripheral nerves.
Mert T, Gunay I, Gocmen C, Kaya M, Polat S.
Department of Biophysics, University of Cukurova School of Medicine, Adana, Turkey.
Previous studies confirm that pulsed magnetic field (PMF) accelerates
functional recovery after a nerve crush lesion. The contention that PMF
enhances the regeneration is still controversial, however. The
influence of a new PMF application protocol (trained PMF) on nerve
regeneration was studied in a model of crush injury of the sciatic nerve
of rats. To determine if exposure to PMF influences regeneration, we
used electrophysiological recordings and ultrastructural examinations.
After the measurements of conduction velocity, the sucrose-gap method
was used to record compound action potentials (CAPs) from sciatic
nerves. PMF treatment during the 38 days following the crush injury
enhanced the regeneration. Although the axonal ultrastructures were
generally normal, slight to moderate myelin sheath degeneration was
noted at the lesion site. PMF application for 38 days accelerated nerve
conduction velocity, increased CAP amplitude and decreased the time to
peak of the CAP. Furthermore, corrective effects of PMF on. the abnormal
characteristics of sensory nerve fibers were determined. Consequently,
long-periodic trained-PMF may promote both morphological and
electrophysiological properties of the injured nerves. In addition,
corrective effects of PMF on sensory fibers may be considered an
important finding for neuropathic pain therapy.
Neurorehabil Neural Repair. 2004 Mar;18(1):42-6.
Pulsed magnetic field therapy in refractory neuropathic pain
secondary to peripheral neuropathy: electrodiagnostic parameters–pilot
study.
Weintraub MI, Cole SP.
New York Medical College, Briarcliff Manor, New York 10510, USA.
CONTEXT: Neuropathic pain (NP) from peripheral neuropathy (PN) arises
from ectopic firing of unmyelinated C-fibers with accumulation of
sodium and calcium channels. Because pulsed electromagnetic fields
(PEMF) safely induce extremely low frequency (ELF) quasirectangular
currents that can depolarize, repolarize, and hyperpolarize neurons, it
was hypothesized that directing this energy into the sole of one foot
could potentially modulate neuropathic pain.
OBJECTIVE: To determine if 9 consecutive 1-h treatments in
physician’s office (excluding weekends) of a pulsed signal therapy can
reduce NP scores in refractory feet with PN.
DESIGN/SETTING/PATIENTS: 24 consecutive patients with refractory and
symptomatic PN from diabetes, chronic inflammatory demyelinating
polyneuropathy (CIDP), pernicious anemia, mercury poisoning,
paraneoplastic syndrome, tarsal tunnel, and idiopathic sensory
neuropathy were enrolled in this nonplacebo pilot study. The most
symptomatic foot received therapy. Primary endpoints were comparison of
VAS scores at the end of 9 days and the end of 30 days follow-up
compared to baseline pain scores. Additionally, Patients’ Global
Impression of Change (PGIC) questionnaire was tabulated describing
response to treatment. Subgroup analysis of nerve conduction scores,
quantified sensory testing (QST), and serial examination changes were
also tabulated. Subgroup classification of pain (Serlin) was utilized to
determine if there were disproportionate responses.
INTERVENTION: Noninvasive pulsed signal therapy generates a
unidirectional quasirectangular waveform with strength about 20 gauss
and a frequency about 30 Hz into the soles of the feet for 9 consecutive
1-h treatments (excluding weekends). The most symptomatic foot of each
patient was treated.
RESULTS: All 24 feet completed 9 days of treatment. 15/24 completed
follow-up (62%) with mean pain scores decreasing 21% from baseline to
end of treatment (P=0.19) but with 49% reduction of pain scores from
baseline to end of follow-up (P<0.01). Of this group, self-reported
PGIC was improved 67% (n=10) and no change was 33% (n=5). An
intent-to-treat analysis based on all 24 feet demonstrated a 19%
reduction in pain scores from baseline to end of treatment (P=0.10) and a
37% decrease from baseline to end of follow-up (P<0.01). Subgroup
analysis revealed 5 patients with mild pain with nonsignificant
reduction at end of follow-up. Of the 19 feet with moderate to severe
pain, there was a 28% reduction from baseline to end of treatment
(P<0.05) and a 39% decrease from baseline to end of follow-up
(P<0.01). Benefit was better in those patients with axonal changes
and advanced CPT baseline scores. The clinical examination did not
change. There were no adverse events or safety issues.
CONCLUSIONS: These pilot data demonstrate that directing PEMF to
refractory feet can provide unexpected short term analgesic effects in
more than 50% of individuals. The role of placebo is not known and was
not tested. The precise mechanism is unclear yet suggests that severe
and advanced cases are more magnetically sensitive. Future studies are
needed with randomized placebo-controlled design and longer treatment
periods.
Arch Phys Med Rehabil. 2003 May;84(5):736-46.
Static magnetic field therapy for symptomatic diabetic neuropathy: a randomized double-blind, placebo-controlled trial.
Weintraub MI, Wolfe GI, Barohn RA, Cole SP, Parry GJ, Hayat G, Cohen
JA, Page JC, Bromberg MB, Schwartz SL; Magnetic Research Group.
Department of Neurology, New York Medical College, Valhalla, NY, USA. miwneuro@pol.net
OBJECTIVE: To determine if constant wearing of multipolar, static
magnetic (450G) shoe insoles can reduce neuropathic pain and quality of
life (QOL) scores in symptomatic diabetic peripheral neuropathy (DPN).
PARTICIPANTS: Three hundred seventy-five subjects with DPN stage II
or III were randomly assigned to wear constantly magnetized insoles for 4
months; the placebo group wore similar, unmagnetized device.
INTERVENTION: Nerve conduction and/or quantified sensory testing were performed serially.
MAIN OUTCOME MEASURES: Daily visual analog scale scores for numbness
or tingling and burning and QOL issues were tabulated over 4 months.
Secondary measures included nerve conduction changes, role of placebo,
and safety issues. Analysis of variance (ANOVA), analysis of covariance
(ANCOVA), and chi-square analysis were performed.
RESULTS: There were statistically significant reductions during the
third and fourth months in burning (mean change for magnet treatment,
-12%; for sham, -3%; P<.05, ANCOVA), numbness and tingling (magnet,
-10%; sham, +1%; P<.05, ANCOVA), and exercise-induced foot pain
(magnet, -12%; sham, -4%; P<.05, ANCOVA). For a subset of patients
with baseline severe pain, statistically significant reductions occurred
from baseline through the fourth month in numbness and tingling
(magnet, -32%; sham, -14%; P<.01, ANOVA) and foot pain (magnet, -41%;
sham, -21%; P<.01, ANOVA).
CONCLUSIONS: Static magnetic fields can penetrate up to 20mm and
appear to target the ectopic firing nociceptors in the epidermis and
dermis. Analgesic benefits were achieved over time.
Neurosci Behav Physiol. 2003 Oct;33(8):745-52.
The use of pulsed electromagnetic fields with complex modulation in the treatment of patients with diabetic polyneuropathy.
Musaev AV, Guseinova SG, Imamverdieva SS.
Science Research Institute of Medical Rehabilitation, Baku, Azerbaidzhan.
Clinical and electroneuromyographic studies were performed in 121
patients with diabetic polyneuropathy (DPN) before and after courses of
treatment with pulsed electromagnetic fields with complex modulation
(PEMF-CM) at different frequencies (100 and 10 Hz). Testing of patients
using the TSS and NIS LL scales demonstrated a correlation between the
severity and frequency of the main subjective and objective effects of
disease and the stage of DPN. The severity of changes in the
segmental-peripheral neuromotor apparatus–decreases in muscle
bioelectrical activity, the impulse conduction rate along efferent
fibers of peripheral nerves, and the amplitude of the maximum M
response–depended on the stage of DPN and the duration of diabetes
mellitus. The earliest and most significant electroneuromyographic signs
of DPN were found to be decreases in the amplitude of the H reflex and
the Hmax/Mmax ratio in the muscles of the lower leg. Application of
PEMF-CM facilitated regression of the main clinical symptoms of DPN,
improved the conductive function of peripheral nerves, improved the
state of la afferents, and improved the reflex excitability of
functionally diverse motoneurons in the spinal cord. PEMF-CM at 10 Hz
was found to have therapeutic efficacy, especially in the initial stages
of DPN and in patients with diabetes mellitus for up to 10 years.
The use of combined methods of magnetoelectrotherapy in treating polyneuropathies.
[Article in Russian]
A comparative evaluation by such parameters as alleviation of pain
syndrome, improvement of peripheral resistance and vegetotrophic
processes, a decline in pareses and sensory disorders has been performed
in 3 groups of patients: group 1 underwent benzohexonium
electrophoresis, group 2 benzohexonium electrophoresis in the magnetic
field produced by the unit “Polyus-I” followed by low-frequency
electrotherapy with bipolar impulse current, group 3 benzohexonium
electrophoresis in the magnetic field from the unit “ADMT-Magnipuls”
followed by low-frequency electrotherapy with bipolar impulse current.
The best clinical and physiological results were reported in group 3
patients.
Wiad Lek. 2003;56(9-10):434-41.
Application of variable magnetic fields in medicine–15 years experience.
[Article in Polish]
Sieron A, Cieslar G.
Katedra i Klinika Chorob Wewnetrznych, Angiologii i Medycyny Fizykalnej SAM, ul. Batorego 15, 41-902 Bytom. sieron@mediclub.pl
The results of 15-year own experimental and clinical research on
application of variable magnetic fields in medicine were presented. In
experimental studies analgesic effect (related to endogenous opioid
system and nitrogen oxide activity) and regenerative effect of variable
magnetic fields with therapeutical parameters was observed. The
influence of this fields on enzymatic and hormonal activity, free oxygen
radicals, carbohydrates, protein and lipid metabolism, dielectric and
rheological properties of blood as well as behavioural reactions and
activity of central dopamine receptor in experimental animals was
proved. In clinical studies high therapeutic efficacy of magnetotherapy
and magnetostimulation in the treatment of osteoarthrosis, abnormal
ossification, osteoporosis, nasosinusitis, multiple sclerosis,
Parkinson’s disease, spastic paresis, diabetic polyneuropathy and
retinopathy, vegetative neurosis, peptic ulcers, colon irritable and
trophic ulcers was confirmed.
Klin Med (Mosk). 1996;74(5):39-41.
Magentotherapy in the comprehensive treatment of vascular complications of diabetes mellitus.
320 diabetes mellitus (DM) patients were exposed to impulsed magnetic
field, 100 control DM patients received conservative therapy alone. 270
patients had microangiopathy, macroangiopathy was diagnosed in 50
patients. Good and satisfactory results of magnetotherapy in combination
with conservative methods were achieved in 74% of patients versus 28%
in control group. Metabolism stabilization resulted in some patients in
reduced blood sugar. Use of magnetic field produced faster and longer
response than conservative therapy.
Vestn Oftalmol. 1990 Sep-Oct;106(5):54-7.
Effectiveness of magnetotherapy in optic nerve atrophy. A preliminary study.
Magnetotherapy effects on visual functions (vision acuity and field),
on retinal bioelectric activity, on conductive vision system, and on
intraocular circulation were studied in 88 patients (160 eyes) with
optic nerve atrophy. A Soviet Polyus-1 low-frequency magnetotherapy
apparatus was employed with magnetic induction of about 10 mT, exposure
7-10 min, 10-15 sessions per course. Vision acuity of patients with its
low (below 0.04 diopters) values improved in 50 percent of cases. The
number of patients with vision acuity of 0.2 diopters has increased from
46 before treatment to 75. Magnetotherapy improved ocular hemodynamics
in patients with optic nerve atrophy, it reduced the time of stimulation
conduction along the vision routes and stimulated the retinal ganglia
cells. The maximal effect was achieved after 10 magnetotherapy sessions.
A repeated course carried out in 6-8 months promoted a stabilization of
the process.
Int J Neurosci. 1998 Apr;93(3-4):239-50.
Treatment with AC pulsed electromagnetic fields normalizes the
latency of the visual evoked response in a multiple sclerosis patient
with optic atrophy.
Sandyk R.
Department of Neuroscience at the Institute for Biomedical
Engineering and Rehabilitation Services of Touro College, Dix Hills, NY
11746, USA.
Visual evoked response (VER) studies have been utilized as supportive
information for the diagnosis of multiple sclerosis (MS) and may be
useful in objectively monitoring the effects of various therapeutic
modalities. Delayed latency of the VER, which reflects slowed impulse
transmission in the optic pathways, is the most characteristic
abnormality associated with the disease. Brief transcranial applications
of AC pulsed electromagnetic fields (EMFs) in the picotesla flux
density are efficacious in the symptomatic treatment of MS and may also
reestablish impulse transmission in the optic pathways. A 36 year old
man developed an attack of right sided optic neuritis at the age of 30.
On presentation he had blurring of vision with reduced acuity on the
right and fundoscopic examination revealed pallor of the optic disc. A
checkerboard pattern reversal VER showed a delayed latency to right eye
stimulation (P100 = 132 ms; normal range: 95-115 ms). After he received
two successive applications of AC pulsed EMFs of 7.5 picotesla flux
density each of 20 minutes duration administered transcranially, there
was a dramatic improvement in vision and the VER latency reverted to
normal (P100= 107 ms). The rapid improvement in vision coupled with the
normalization of the VER latency despite the presence of optic atrophy,
which reflects chronic demyelination of the optic nerve, cannot be
explained on the basis of partial or full reformation of myelin. It is
proposed that in MS synaptic neurotransmitter deficiency is associated
with the visual impairment and delayed VER latency following optic
neuritis and that the recovery of the VER latency by treatment with
pulsed EMFs is related to enhancement of synaptic neurotransmitter
functions in the retina and central optic pathways. Recovery of the VER
latency in MS patients may have important implications with respect to
the treatment of visual impairment and prevention of visual loss.
Specifically, repeated pulsed applications of EMFs may maintain impulse
transmission in the optic nerve and thus potentially sustain its
viability.
Altern Ther Health Med. 2003 Jul-Aug;9(4):38-48.
Effects of a pulsed electromagnetic therapy on multiple sclerosis
fatigue and quality of life: a double-blind, placebo-controlled trial.
Lappin MS, Lawrie FW, Richards TL, Kramer ED.
Energy Medicine Developments, (North America), Inc., Burke, Va., USA.
CONTEXT: There is a growing literature on the biological and clinical
effects of pulsed electromagnetic fields. Some studies suggest that
electromagnetic therapies may be useful in the treatment of chronic
illnesses. This study is a follow-up to a placebo controlled pilot study
in which multiple sclerosis (MS) patients exposed to weak, extremely
low frequency pulsed electromagnetic fields showed significant
improvements on a composite symptom measure.
OBJECTIVE: To evaluate the effects of a pulsed electromagnetic
therapy on MS related fatigue, spasticity, bladder control, and overall
quality of life.
DESIGN: A multi-site, double-blind, placebo controlled, crossover
trial. Each subject received 4 weeks of the active and placebo
treatments separated by a 2-week washout period. SETTING: The University
of Washington Medical Center in Seattle Wash, the Neurology Center of
Fairfax in Fairfax, Va, and the headquarters of the Multiple Sclerosis
Association of America in Cherry Hill, NJ.
SUBJECTS: 117 patients with clinically definite MS.
INTERVENTION: Daily exposure to a small, portable pulsing electromagnetic field generator.
MAIN OUTCOME: The MS Quality of Life Inventory (MSQLI) was used to
assess changes in fatigue, bladder control, spasticity, and a quality of
life composite.
RESULTS: Paired t-tests were used to assess treatment differences in
the 117 subjects (81% of the initial sample) who completed both
treatment sessions. Improvements in fatigue and overall quality of life
were significantly greater on the active device. There were no treatment
effects for bladder control and a disability composite, and mixed
results for spasticity.
CONCLUSIONS: Evidence from this randomized, double-bind, placebo
controlled trial is consistent with results from smaller studies
suggesting that exposure to pulsing, weak electromagnetic fields can
alleviate symptoms of MS. The clinical effects were small, however, and
need to be replicated. Additional research is also needed to examine the
possibility that ambulatory patients and patients taking interferons
for their MS may be most responsive to this kind of treatment.
Phys Med Rehabil Clin N Am. 1998 Aug;9(3):659-74.
Bioelectromagnetic applications for multiple sclerosis.
Richards TL, Lappin MS, Lawrie FW, Stegbauer KC.
Department of Radiology, University of Washington, Seattle, USA.
There are EM effects on biology that are potentially both harmful and
beneficial. We have reviewed applications of EM fields that are
relevant to MS. It is possible that EM fields could be developed into a
reproducible therapy for both symptom management and long-term care for
MS. The long-term care for MS would have to include beneficial changes
in the immune system and in nerve regeneration.
Mult Scler. 2005 Jun;11(3):302-5.
Effect of pulsed magnetic field therapy on the level of fatigue in
patients with multiple sclerosis–a randomized controlled trial.
Mostert S, Kesselring J.
Department of Neurology, Rehabilitation Centre, CH 7317 Valens, Switzerland.
Twenty-five multiple sclerosis patients, taking part in a
rehabilitation program, were randomly assigned to treatment with pulsed
magnetic field therapy (PMFT) or to sham therapy in order to study the
additional effect of PMFT as part of a multimodal neurological
rehabilitation program on fatigue. Patients demographic and disease
specific characteristics were recorded. Level of fatigue was measured by
fatigue severity scale (FSS) at entrance and discharge and with a
visual analog scale (VAS) immediate before and after a single treatment
session. The ‘Magnetic Cell Regeneration’ system by Santerra was used
for PMFT. A single treatment lasted 16 minutes twice daily over 3-4
weeks and consisted of relaxed lying on a PMF mattress. Sham
intervention was conducted in an identical manner with the PMF-device
off. Patients and statistics were blinded. Level of fatigue measured by
FSS was high at entrance in both treatment group (TG) and control group
(CG) (5.6 versus 5.5). Over time of rehabilitation fatigue was reduced
by 18% in TG and 7% in CG which was statistically not significant. There
was a statistically significant immediate effect of the single
treatment session which 18% reduction of fatigue measured by VAS in TG
versus 11% in CG. Because of a high ‘placebo effect’ of simple bed rest,
a only small and short lasting additional effect of PMFT and high costs
of a PMF-device, we cannot recommend PMFT as an additional feature of a
multimodal neurological rehabilitation program in order to reduce
fatigue level of MS-patients.
Int J Neurosci. 1997 Nov;92(1-2):95-102.
Treatment with electromagnetic fields improves dual-task performance (talking while walking) in multiple sclerosis.
Sandyk R.
Department of Neuroscience, Touro College, Dix Hills, NY 11746, USA.
Multiple sclerosis (MS) is associated with an increased risk of
falling resulting from visual disturbances, difficulties with gait and
balance, apraxia of gait and peripheral neuropathy. These factors often
interact synergistically to compromise the patient’s gait stability. It
has long been recognized that walking involves a cognitive component and
that simultaneous cognitive and motor operations (dual-task) such as
talking while walking may interfere with normal ambulation. Talking
while walking reflects an example of a dual-task which is frequently
impaired in MS patients. Impaired dual-task performance during walking
may compromise the patient’s gait and explain why in some circumstances,
MS patients unexpectedly lose their balance and fall. Frontal lobe
dysfunction, which commonly occurs in MS patients, may disrupt dual-task
performance and increase the risk of falling in these patients. This
report concerns a 36 old man with remitting-progressive MS with an EDSS
score of 5.5 who experienced marked increase in spasticity in the legs
and trunk and worsening of his gait and balance, occasionally resulting
in falling, when talking while walking. His gait and balance improved
dramatically after he received two successive transcranial treatments,
each of 45 minutes, with AC pulsed electromagnetic fields (EMFs) of 7.5
picotesla flux density. Simultaneously, there was improvement in
dual-task performance to the extent that talking while walking did not
adversely affect his ambulation. In addition, neuropsychological testing
revealed an almost 5-fold increase in word output on the Thurstone’s
Word-Fluency Test, which is sensitive to frontal lobe dysfunction. It is
suggested that facilitation of dual-task performance during ambulation
contributes to the overall improvement of gait and balance observed in
MS patients receiving transcranial treatment with AC pulsed EMFs.
Int J Neurosci. 1997 Aug;90(3-4):177-85.
Treatment with electromagnetic fields reverses the long-term
clinical course of a patient with chronic progressive multiple
sclerosis.
Sandyk R.
Department of Neuroscience, Touro College, Dix Hills, NY 11746, USA.
It is estimated that 10-20% of patients with multiple sclerosis (MS)
have a chronic progressive (CP) course characterized by an insidious
onset of neurological deficits followed by steady progression of
disability in the absence of symptomatic remission. To date no
therapeutic modality has proven effective in reversing the clinical
course of CP MS although there are indications that prolonged treatment
with picotesla electromagnetic fields (EMFs) alters the clinical course
of patients with CP MS. A 40 year-old woman presented in December of
1992 with CP MS with symptoms of spastic paraplegia, loss of trunk
control, marked weakness of the upper limbs with loss of fine and gross
motor hand functions, severe fatigue, cognitive deficits, mental
depression, and autonomic dysfunction with neurogenic bladder and bowel
incontinence. Her symptoms began at the age of 18 with weakness of the
right leg and fatigue with long distance walking and over the ensuing
years she experienced steady deterioration of functions. In 1985 she
became wheelchair dependent and it was anticipated that within 1-2 years
she would become functionally quadriplegic. In December of 1992 she
began experimental treatment with EMFs. While receiving regularly weekly
transcortical treatments with AC pulsed EMFs in the picotesla range
intensity she experienced during the first year improvement in mental
functions, return of strength in the upper extremities, and recovery of
trunk control. During the second year she experienced the return of more
hip functions and recovery of motor functions began in her legs. For
the first time in years she can now initiate dorsiflexion of her ankles
and actively extend her knees voluntarily. Over the past year she
started to show signs of redevelopment of reciprocal gait. Presently,
with enough function restored in her legs, she is learning to walk with a
walker and is able to stand unassisted and maintain her balance for a
few minutes. She also regained about 80% of functions in the upper limbs
and hands. Most remarkably, there was no further progression of the
disease during the 4 years course of magnetic therapy. This patient’s
clinical recovery cannot be explained on the basis of a spontaneous
remission. It is suggested that pulsed applications of picotesla EMFs
affect the neurobiological and immunological mechanisms underlying the
pathogenesis of CP MS.
Int J Neurosci. 1997 Aug;90(3-4):145-57.
Resolution of sleep paralysis by weak electromagnetic fields in a patient with multiple sclerosis.
Sandyk R.
Department of Neuroscience, Touro College, Dix Hills, NY 11746, USA.
Sleep paralysis refers to episodes of inability to move during the
onset of sleep or more commonly upon awakening. Patients often describe
the sensation of struggling to move and may experience simultaneous
frightening vivid hallucinations and dreams. Sleep paralysis and other
manifestations of dissociated states of wakefulness and sleep, which
reflect deficient monoaminergic regulation of neural modulators of REM
sleep, have been reported in patients with multiple sclerosis (MS). A 40
year old woman with remitting-progressive multiple sclerosis (MS)
experienced episodes of sleep paralysis since the age of 16, four years
prior to the onset of her neurological symptoms. Episodes of sleep
paralysis, which manifested at a frequency of about once a week,
occurred only upon awakening in the morning and were considered by the
patient as a most terrifying experience. Periods of mental stress, sleep
deprivation, physical fatigue and exacerbation of MS symptoms appeared
to enhance the occurrence of sleep paralysis. In July of 1992 the
patient began experimental treatment with AC pulsed applications of
picotesla intensity electromagnetic fields (EMFs) of 5Hz frequency which
were applied extracerebrally 1-2 times per week. During the course of
treatment with EMFs the patient made a dramatic recovery of symptoms
with improvement in vision, mobility, balance, bladder control, fatigue
and short term memory. In addition, her baseline pattern reversal visual
evoked potential studies, which showed abnormally prolonged latencies
in both eyes, normalized 3 weeks after the initiation of magnetic
therapy and remained normal more than 2.5 years later. Since the
introduction of magnetic therapy episodes of sleep paralysis gradually
diminished and abated completely over the past 3 years. This report
suggests that MS may be associated with deficient REM sleep inhibitory
neural mechanisms leading to sleep paralysis secondary to the intrusion
of REM sleep atonia and dream imagery into the waking state. Pineal
melatonin and monoaminergic neurons have been implicated in the
induction and maintenance of REM sleep and the pathogenesis of sleep
paralysis and it is suggested that resolution of sleep paralysis in this
patient by AC pulsed applications of EMFs was related to enhancement of
melatonin circadian rhythms and cerebral serotoninergic
neurotransmission.
Int J Neurosci. 1997 Jun;90(1-2):59-74.
Immediate recovery of cognitive functions and resolution of fatigue
by treatment with weak electromagnetic fields in a patient with multiple
sclerosis.
Sandyk R.
Department of Neuroscience, Institute for Biomedical Engineering, Dix Hills, NY, USA.
Cognitive deficits are common among patients with multiple sclerosis
(MS). The pathogenetic mechanisms underlying the cognitive impairment in
MS are unknown and there is presently no effective therapeutic modality
which has shown efficacy in improving cognitive deficits in MS. A 53
year old college professor with a long history of secondary progressive
MS experienced, over the preceding year, noticeable deterioration in
cognitive functions with difficulties in short and long term memory,
word finding in spontaneous speech, attention and concentration span.
Unable to pursue his academic activities, he was considering early
retirement. Mental examination disclosed features of subcortical and
cortical dementia involving frontal lobe, left hemispheric and right
hemispheric dysfunction. Almost immediately following the extracerebral
application of AC pulsed electromagnetic fields (EMFs) of 7.5 picotesla
intensity and a 4-Hz sinusoidal wave, the patient experienced a
heightend sense of well being, which he defined as enhancement of
cognitive functions with a feeling “like a cloud lifted off my head.” He
reported heightend clarity of thinking and during the application of
EMFs he felt that words were formed faster and he experienced no
difficulty finding the appropriate words. His speech was stronger and
well modulated and he felt “energized” with resolution of his fatigue.
There was improvement in manual dexterity and handwriting and testing of
constructional praxis demonstrated improvement in visuospatial,
visuoperceptive and visuomotor functions. It is suggested that some of
the cognitive deficits associated with MS, which are caused by synaptic
disruption of neurotransmitter functions, may be reversed through pulsed
applications of picotesla range EMFs.
Int J Neurosci. 1996 Oct;87(1-2):5-15.
Suicidal behavior is attenuated in patients with multiple sclerosis by treatment with electromagnetic fields.
Sandyk R.
NeuroCommunication Research Laboratories, Danbury, CT 06811, USA.
A marked decrease in the levels of serotonin (5-HT) and its
metabolite (5-HIAA) has been demonstrated in postmortem studies of
suicide victims with various psychiatric disorders. Depression is the
most common mental manifestation of multiple sclerosis (MS) which
accounts for the high incidence of suicide in this disease. CSF 5-HIAA
concentrations are reduced in MS patients and nocturnal plasma melatonin
levels were found to be lower in suicidal than in nonsuicidal patients.
These findings suggest that the increased risk of suicide in MS
patients may be related to decreased 5-HT functions and blunted
circadian melatonin secretion. Previous studies have demonstrated that
extracerebral applications of pulsed electromagnetic fields (EMFs) in
the picotesla range rapidly improved motor, sensory, affective and
cognitive deficits in MS. Augmentation of cerebral 5-HT synthesis and
resynchronization of circadian melatonin secretion has been suggested as
a key mechanism by which these EMFs improved symptoms of the disease.
Therefore, the prediction was made that this treatment modality would
result in attenuation of suicidal behavior in MS patients. The present
report concerns three women with remitting-progressive MS who exhibited
suicidal behavior during the course of their illness. All patients had
frequent suicidal thoughts over several years and experienced resolution
of suicidal behavior within several weeks after introduction of EMFs
treatment with no recurrence of symptoms during a follow-up of months to
3.5 years. These findings demonstrate that in MS pulsed applications of
picotesla level EMFs improve mental depression and may reduce the risk
of suicide by a mechanism involving the augmentation of 5-HT
neurotransmission and resynchronization of circadian melatonin
secretion.
Int J Neurosci. 1996 Jul;86(1-2):79-85.
Effect of weak electromagnetic fields on body image perception in patients with multiple sclerosis.
Sandyk R.
NeuroCommunication Research Laboratories, Danbury, CT 06811, USA.
Cerebellar ataxia is one of the most disabling symptoms of multiple
sclerosis (MS) and also one of the least responsive to pharmacotherapy.
However, cerebellar symptoms often improve dramatically in MS patients
by brief, extracerebral applications of picotesla flux electromagnetic
fields (EMFs). This report concerns two MS patients with chronic
disabling ataxia who experienced rapid improvement in gait and balance
after receiving a series of treatments with EMFs. To assess whether
improvement in cerebellar gait is accompanied by changes in body image
perception, a parietal lobe function, both patients were administered
the Human Figure Drawing Test before and after a series of brief
treatments with EMFs. Prior to application of EMFs these patients’ free
drawings of a person showed a figure with a wide-based stance
characteristic of cerebellar ataxia. After receiving a series of EMFs
treatments both patients demonstrated a change in body image perception
with the drawings of the human figure showing a normal stance. These
findings demonstrate that in MS improvement in cerebellar symptoms by
pulsed applications of picotesla EMFs is associated with changes in the
body image.
Int J Neurosci. 1996 Jul;86(1-2):67-77.
Treatment with weak electromagnetic fields attenuates carbohydrate cravings in a patients with multiple sclerosis.
Sandyk R.
NeuroCommunication Research Laboratories, Danbury, CT 06811, USA.
Pharmacological studies have implicated serotonergic (5-HT) neurons
in the regulation of food intake and food preference. It has been shown
that the urge to consume carbohydrate rich foods is regulated by 5-HT
activity and that carbohydrate craving is triggered by 5-HT deficiency
in the medical hypothalamus. Ingestion of carbohydrate foods stimulates
insulin secretion which accelerates the uptake of tryptophan, the
precursor of 5-HT and melatonin, into the brain and pineal gland,
respectively. Thus, carbohydrate craving might be considered a form of
“self medication” aimed at correcting an underlying dysfunction of
cerebral 5-HT and pineal melatonin functions. A 51 year old woman with
remitting-progressive MS experienced carbohydrate craving during
childhood and adolescence and again in temporal association with the
onset of her first neurological symptoms at the age of 45. Carbohydrate
craving, which resembled the pattern observed in patients with seasonal
affective disorder (SAD), was attenuated by a series of extracranial AC
pulsed applications of picotesla (10(-12) Tesla) flux intensity
electromagnetic fields (EMFs). It is suggested that AC pulsed EMFs
applications activated retinal mechanisms which, through functional
interactions with the medial hypothalamus, initiated an increased
release of 5-HT and resynchronization of melatonin secretion ultimately
leading to a decrease in carbohydrate craving. The occurrence of
carbohydrate craving in early life may have increased the patient’s
vulnerability to viral infection given the importance of 5-HT and
melatonin in immunomodulation and the regulation of the integrity of the
blood brain barrier. The recurrence of this craving in temporal
relation to the onset of neurological symptoms suggests that 5-HT
deficiency and impaired pineal melatonin functions are linked to the
timing of onset of the clinical symptoms of the disease. The report
supports the role of experimental factors in the pathophysiology of MS.
Int J Neurosci. 1995 Nov;83(1-2):81-92.
Resolution of dysarthria in multiple sclerosis by treatment with weak electromagnetic fields.
Sandyk R.
NeuroCommunication Research Laboratories, Danbury, CT 06811, USA.
It has been reported that 50% or more of patients diagnosed with
multiple sclerosis (MS) exhibit speech impairment (dysarthria) which in
some cases can be exceedingly disabling. Currently there is no effective
medical treatment for the dysarthria of MS which occurs as a result of
lesions to the cerebellum and its outflow tracts. It was reported
recently that extracranial application of brief AC pulsed
electromagnetic fields (EMFs) in the picotesla (pT) range intensity
produced in patients with MS sustained improvement in motor functions
including cerebellar symptomatology. This communication concerns two MS
patients with a chronic progressive course who exhibited severe
dysarthria which improved already during the initial treatment with
pulsed EMFs and which resolved completely 3-4 weeks later. Since
application of EMFs has been shown to alter: (a) the resting membrane
potential and synaptic neurotransmitter release through an effect
involving changes in transmembrane calcium flux; and (b) the secretion
of pineal melatonin which in turn influences the synthesis and release
of serotonin (5-HT) and gamma-amino butyric acid (GABA) in the
cerebellum, it is suggested that the immediate improvement of the
dysarthria occurred as a result of changes in cerebellar
neurotransmitter functions particularly 5-HT and GABA rather than from
remyelination.
Int J Neurosci. 1995 Jun;82(3-4):223-42.
Chronic relapsing multiple sclerosis: a case of rapid recovery by application of weak electromagnetic fields.
Sandyk R.
NeuroCommunication Research Laboratories, Danbury, CT 06811, USA.
A 54 year-old woman was diagnosed with multiple sclerosis (MS) in
1985 at the age of 45 after she developed diplopia, slurred speech, and
weakness in the right leg. A Magnetic Resonance Imaging (MRI) scan
obtained in 1985 showed several areas of plaque formation distributed in
the periventricular white matter and centrum semiovale bilaterally.
Coincident with slow deterioration in her condition since 1990 a second
MRI scan was obtained in 1991 which showed a considerable increase in
the number and size of plaques throughout both cerebral hemispheres,
subcortical white matter, periventricularly and brainstem. In 1994, the
patient received treatment with Interferon beta- 1b (Betaseron) for 6
months with no improvement in symptoms. However, following two
successive extracranial applications of pulsed electromagnetic fields
(EMFs) in the picotesla (pT) range each of 20 minutes duration the
patient experienced an immediate improvement in symptoms most
dramatically in gait, balance, speech, level of energy, swallowing,
mood, and vision. On a maintenance program of 3 treatments per month the
patient’s only symptom is mild right foot and leg weakness. The report
points to the unique efficacy of externally applied pT range EMFs in the
symptomatic treatment of MS, indicates a lack of an association between
the extent of demyelinating plaques on MRI scan and rate and extent of
recovery in response to EMFs, and supports the notion that dysfunction
of synaptic conductivity due to neurotransmitter deficiency particularly
of serotonin (5-HT) contributes more significantly to the development
of MS symptoms than the process of demyelination which clinically seems
to represent an epiphenomenon of the disease.
Int J Neurosci. 1994 Dec;79(3-4):199-212.
Weak electromagnetic fields attenuate tremor in multiple sclerosis.
Sandyk R, Dann LC.
NeuroCommunication Research Laboratories, Danbury, CT 06811, USA.
It has been estimated that about 75% of patients diagnosed with
multiple sclerosis (MS) have tremor which can be exceedingly disabling.
The most common tremor observed in patients with MS is a cerebellar
intention tremor (‘kinetic tremor’) although postural tremor (‘static
tremor’) is also common and often extremely incapacitating. Currently
there is no effective medical treatment for the tremor of MS which, in
some severe cases, may be abolished by stereotactic thalamotomy. It was
reported recently that extracranial application of brief AC pulsed
electromagnetic fields (EMFs) in the picotesla (pT) range produced
improvement in motor and cognitive functions in patients with MS. The
present communication concerns three MS patients with a chronic
progressive course of the disease (mean age: 39.3 +/- 8.3 years; mean
duration of illness: 11.3 +/- 3.2 years) in whom brief external
applications of pulsed EMFs of 7.5 pT intensity reduced intention and
postural tremors resulting in significant functional improvement. The
report suggests that these extremely low intensity EMFs are beneficial
also in the treatment of tremors in MS and that this treatment may serve
as an alternative method to stereotactic thalamotomy in the management
of tremor in MS. The mechanisms by which EMFs attenuate the tremors of
MS are complex and are thought to involve augmentation of GABA and
serotonin (5-HT) neurotransmission in the cerebellum and its outflow
tracts.
Therapeutic effects of alternating current pulsed electromagnetic fields in multiple sclerosis.
Sandyk R. Dep. of Neuroscience, Institute for Biomedical Engineering and Rehab Services of Touro College, Dix Hills, New York.
Multiple sclerosis is the third most common cause of severe
disability in patients between the ages of 15 and 50 years. The cause of
the disease and its pathogenesis remain unknown. The last 20 years have
seen only meager advances in the development of effective treatments
for the disease. No specific treatment modality can cure the disease or
alter its long-term course and eventual outcome. Moreover, there are no
agents or treatments that will restore premorbid neuronal function. A
host of biological phenomena associated with the disease involving
interactions among genetic, environmental, immunologic, and hormonal
factors, cannot be explained on the basis of demyelination alone and
therefore require refocusing attention on alternative explanations, one
of which implicates the pineal gland as pivotal. The pineal gland
functions as a magnetoreceptor organ. This biological property of the
gland provided the impetus for the development of a novel and highly
effective therapeutic modality, which involves transcranial applications
of alternating current (AC) pulsed electromagnetic fields flux density.
This review summarizes recent clinical work on the effects of
transcranially applied pulsed electromagnetic fields for the symptomatic
treatment of the disease.
J In Biologic Effects of Light 1998 Symposium
Pulsing magnetic field effects on brain electrical activity in multiple sclerosis.
Richards TL, Acosta-Urquidi,
Multiple sclerosis (MS) is a disease of the central nervous system.
Clinical symptoms include central fatigue, impaired bladder control,
muscle weakness, sensory deficits, impaired cognition, and others. The
cause of MS is unknown, but from histologic, immunologic, and radiologic
studies, we know that there are demyelinated brain lesions (visible on
magnetic resonance images) that contain immune cells such as macrophages
and T-cells (visible on microscopic analysis of brain sections).
Recently, a histologic study has also shown that widespread axonal
damage occurs in MS along with demyelination. What is the possible
connection between MS and bio-electromagnetic fields? We recently
published a review entitled “Bio-electromagnetic applications for
multiple sclerosis,” which examined several scientific studies that
demonstrated the effects of electromagnetic fields on nerve
regeneration, brain electrical activity (electro-encephalography),
neurochemistry, and immune system components. All of these effects are
important for disease pathology and clinical symptoms in multiple
sclerosis (MS). EEG was measured in this study in order to test our
hypothesis that the pulsing magnetic device affects the brain electrical
activity, and that this may be a mechanism for the effect we have
observed on patient-reported symptoms. The EEG data reported previously
were measured only during resting and language conditions. The purpose
of the current study was to measure the effect of the electromagnetic
device on EEG activity during and after photic stimulation with flashing
lights. After photic stimulation, there was a statistically significant
increase in alpha EEG magnitude that was greater in the active group
compared to the placebo group in electrode positions P3, T5, and O1
(analysis of variance p<.001, F=14, DF = 1,16). In the comparison
between active versus placebo, changes measured from three electrode
positions were statistically significantly even after multiple
comparison correction.
Treatment with weak electromagnetic fiels improves fatigue associated with multiple sclerosis.
Sandyk R. NeuroCommunication Research Laboratories, Danbury, CT, USA
It is estimated that 75-90% of patients with multiple sclerosis (MS)
experience fatigue at some point during the course of the disease and
that in about half of these patients, subjective fatigue is a primary
complaint. In the majority of patients fatigue is present throughout the
course of the day being most prominent in the mid to late afternoon.
Sleepiness is not prominent, but patients report that rest may attenuate
fatigability. The pathophysiology of the fatigue of MS remains unknown.
Delayed impulse conduction in demyelinated zones may render
transmission in the brainstem reticular formation less effective. In
addition, the observation that rest may restore energy and that
administration of pemoline and amantadine, which increase the synthesis
and release of monoamines, often improve the fatigue of MS suggest that
depletion of neurotransmitter stores in damaged neurons may contribute
significantly to the development of fatigue in these patients. The
present report concerns three MS patients who experienced over several
years continuous and debilitating fatigue throughout the course of the
day. Fatigue was exacerbated by increased physical activity and was not
improved by rest. After receiving a course of treatments with picotesla
flux electromagnetic fields (EMFs), which were applied extracranially,
all patients experienced improvement in fatigue. Remarkably, patients
noted that several months after initiation of treatment with EMFs they
were able to recover, after a short period of rest, from fatigue which
followed increased physical activity. These observations suggest that
replenishment of monoamine stores in neurons damaged by demyelination in
the brainstem reticular formation by periodic applications of picotesla
flux intensity EMFs may lead to more effective impulse conduction and
thus to improvement in fatigue including rapid recovery of fatigue after
rest.
Int J Neurosci. 1998 Jul;95(1-2):107-13.
Yawning and stretching–a behavioral syndrome associated with
transcranial application of electromagnetic fields in multiple
sclerosis.
Sandyk R.
Department of Neuroscience at the Institute for Biomedical
Engineering and Rehabilitation Services of Touro College, Dix Hills, NY
11746, USA.
Intracerebral administration of adrenocorticotropic hormone (ACTH)
elicits in experimental animals a yawning stretching behavior which is
believed to reflect an arousal response mediated through the
septohippocampal cholinergic neurons. A surge in plasma ACTH levels at
night and just prior to awakening from sleep is also associated in
humans with yawning and stretching behavior. Recurrent episodes of
uncontrollable yawning and body stretching, identical to those observed
upon awakening from physiological sleep, occur in a subset of patients
with multiple sclerosis (MS) during transcranial therapeutic application
of AC pulsed electromagnetic fields of picotesla flux density. This
behavioral response has been observed exclusively in young female
patients who are fully ambulatory with a relapsing remitting course of
the disease who also demonstrate a distinctly favorable therapeutic
response to magnetic stimulation. ACTH is employed for the treatment of
MS due to its immunomodulatory effects and a surge in its release in
response to AC pulsed magnetic stimulation could explain some of the
mechanism by which these fields improve symptoms of the disease.
Int J Neurosci. 1997 Jan;89(1-2):39-51.
Progressive cognitive improvement in multiple sclerosis from treatment with electromagnetic fields.
Sandyk R.
Department of Neuroscience, Touro College, Dix Hills, NY 11746, USA.
It has long been recognized that cognitive impairment occurs in
patients with multiple sclerosis (MS) particularly among patients with a
chronic progressive course. MS is considered a type of “subcortical
dementia” in which cognitive and behavioral abnormalities resemble those
observed in patients with a frontal lobe syndrome. The Bicycle Drawing
Test is employed for the neuropsychological assessment of cognitive
impairment specifically that of mechanical reasoning and visuographic
functioning. It also provides clues concerning the patient’s
organizational skills which are subserved by the frontal lobes.
Extracerebral pulsed applications of picotesla flux intensity
electromagnetic fields (EMFs) have been shown to improve cognitive
functions in patients with MS. I present three patients with long
standing symptoms of MS who, on the initial baseline, pretreatment
Bicycle Drawing Test, exhibited cognitive impairment manifested by
omissions of essential details and deficient organizational skills. All
patients demonstrated progressive improvement in their performance
during treatment with EMFs lasting from 6-18 months. The improvement in
cognitive functions, which occurred during the initial phases of the
treatment, was striking for the changes in organizational skills
reflecting frontal lobe functions. These findings demonstrate that
progressive recovery of cognitive functions in MS patients are observed
over time through continued administration of picotesla flux intensity
EMFs. It is believed that the beneficial cognitive effects of these EMFs
are related to increased synaptic neurotransmission and that the
progressive cognitive improvement noted in these patients is associated
with slow recovery of synaptic functions in monoaminergic neurons of the
frontal lobe or its projections from subcortical areas.
Wiad Lek. 2003;56(9-10):434-41.
Application of variable magnetic fields in medicine–15 years experience.
[Article in Polish]
Sieron A, Cieslar G.
Katedra i Klinika Chorob Wewnetrznych, Angiologii i Medycyny Fizykalnej SAM, ul. Batorego 15, 41-902 Bytom. sieron@mediclub.pl
The results of 15-year own experimental and clinical research on
application of variable magnetic fields in medicine were presented. In
experimental studies analgesic effect (related to endogenous opioid
system and nitrogen oxide activity) and regenerative effect of variable
magnetic fields with therapeutical parameters was observed. The
influence of this fields on enzymatic and hormonal activity, free oxygen
radicals, carbohydrates, protein and lipid metabolism, dielectric and
rheological properties of blood as well as behavioural reactions and
activity of central dopamine receptor in experimental animals was
proved. In clinical studies high therapeutic efficacy of magnetotherapy
and magnetostimulation in the treatment of osteoarthrosis, abnormal
ossification, osteoporosis, nasosinusitis, multiple sclerosis,
Parkinson’s disease, spastic paresis, diabetic polyneuropathy and
retinopathy, vegetative neurosis, peptic ulcers, colon irritable and
trophic ulcers was confirmed.
Ann Neurol. 2005 Oct 20; [Epub ahead of print]
Altered plasticity of the human motor cortex in Parkinson’s disease.
Ueki Y, Mima T, Ali Kotb M, Sawada H, Saiki H, Ikeda A, Begum T, Reza F, Nagamine T, Fukuyama H.
Human Brain Research Center, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto, Japan.
Interventional paired associative stimulation (IPAS) to the
contralateral peripheral nerve and cerebral cortex can enhance the
primary motor cortex (M1) excitability with two synchronously arriving
inputs. This study investigated whether dopamine contributed to the
associative long-term potentiation-like effect in the M1 in Parkinson’s
disease (PD) patients. Eighteen right-handed PD patients and 11
right-handed age-matched healthy volunteers were studied. All patients
were studied after 12 hours off medication with levodopa replacement
(PD-off). Ten patients were also evaluated after medication (PD-on). The
IPAS comprised a single electric stimulus to the right median nerve at
the wrist and subsequent transcranial magnetic stimulation of the left
M1 with an interstimulus interval of 25 milliseconds (240 paired stimuli
every 5 seconds for 20 minutes). The motor-evoked potential amplitude
in the right abductor pollicis brevis muscle was increased by IPAS in
healthy volunteers, but not in PD patients. IPAS did not affect the
motor-evoked potential amplitude in the left abductor pollicis brevis.
The ratio of the motor-evoked potential amplitude before and after IPAS
in PD-off patients increased after dopamine replacement. Thus, dopamine
might modulate cortical plasticity in the human M1, which could be
related to higher order motor control, including motor learning. Ann
Neurol 2006.
Int J Neurosci. 1999 Aug;99(1-4):139-49.
AC pulsed electromagnetic fields-induced sexual arousal and penile erections in Parkinson’s disease.
Sandyk R.
Department of Neuroscience at the Institute for Biomedical
Engineering and Rehabilitation Services, Touro College, Bay Shore, NY
11706, USA.
Sexual dysfunction is common in patients with Parkinson’s disease
(PD) since brain dopaminergic mechanisms are involved in the regulation
of sexual behavior. Activation of dopamine D2 receptor sites, with
resultant release of oxytocin from the paraventricular nucleus (PVN) of
the hypothalamus, induces sexual arousal and erectile responses in
experimental animals and humans. In Parkinsonian patients subcutaneous
administration of apomorphine, a dopamine D2 receptor agonist, induces
sexual arousal and penile erections. It has been suggested that the
therapeutic efficacy of transcranial administration of AC pulsed
electromagnetic fields (EMFs) in the picotesla flux density in PD
involves the activation of dopamine D2 receptor sites which are the
principal site of action of dopaminergic pharmacotherapy in PD. Here, 1
report 2 elderly male PD patients who experienced sexual dysfunction
which was recalcitrant to treatment with anti Parkinsonian agents
including selegiline, levodopa and tolcapone. However, brief
transcranial administrations of AC pulsed EMFs in the picotesla flux
density induced in these patients sexual arousal and spontaneous
nocturnal erections. These findings support the notion that central
activation of dopamine D2 receptor sites is associated with the
therapeutic efficacy of AC pulsed EMFs in PD. In addition, since the
right hemisphere is dominant for sexual activity, partly because of a
dopaminergic bias of this hemisphere, these findings suggest that right
hemispheric activation in response to administration of AC pulsed EMFs
was associated in these patient with improved sexual functions
Int J Neurosci. 1999 Apr;97(3-4):225-33.
Treatment with AC pulsed electromagnetic fields improves olfactory function in Parkinson’s disease.
Sandyk R.
Department of Neuroscience at the Institute for Biomedical
Engineering and Rehabilitation Services of Touro College, Dix Hills, NY
11746, USA.
Olfactory dysfunction is a common symptom of Parkinson’s disease
(PD). It may manifest in the early stages of the disease and
infrequently may even antedate the onset of motor symptoms. The cause of
olfactory dysfunction in PD remains unknown. Pathological changes
characteristic of PD (i.e., Lewy bodies) have been demonstrated in the
olfactory bulb which contains a large population of dopaminergic neurons
involved in olfactory information processing. Since dopaminergic drugs
do not affect olfactory threshold in PD patients, it has been suggested
that olfactory dysfunction in these patients is not dependent on
dopamine deficiency. I present two fully medicated Parkinsonian patients
with long standing history of olfactory dysfunction in whom recovery of
smell occurred during therapeutic transcranial application of AC pulsed
electromagnetic fields (EMFs) in the picotesla flux density. In both
patients improvement of smell during administration of EMFs occurred in
conjunction with recurrent episodes of yawning. The temporal association
between recovery of smell and yawning behavior is remarkable since
yawning is mediated by activation of a subpopulation of striatal and
limbic postsynaptic dopamine D2 receptors induced by increased synaptic
dopamine release. A high density of dopamine D2 receptors is present in
the olfactory bulb and tract. Degeneration of olfactory dopaminergic
neurons may lead to upregulation (i.e., supersensitivity) of
postsynaptic dopamine D2 receptors. Presumably, small amounts of
dopamine released into the synapses of the olfactory bulb during
magnetic stimulation may cause activation of these supersensitive
receptors resulting in enhanced sense of smell. Interestingly, in both
patients enhancement of smell perception occurred only during
administration of EMFs of 7 Hz frequency implying that the release of
dopamine and activation of dopamine D2 receptors in the olfactory bulb
was partly frequency dependent. In fact, weak magnetic fields have been
found to cause interaction with biological systems only within narrow
frequency ranges (i.e., frequency windows) and the existence of such
frequency ranges has been explained on the basis of the cyclotron
resonance model.
Int J Neurosci. 1998 Sep;95(3-4):255-69.
Reversal of the bicycle drawing direction in Parkinson’s disease by AC pulsed electromagnetic fields.
Sandyk R.
Department of Neuroscience, Touro College, Dix Hills, NY 11746, USA.
The Draw-a-Bicycle Test is employed in neuropsychological testing of
cognitive skills since the bicycle design is widely known and also
because of its complex structure. The Draw-a-Bicycle Test has been
administered routinely to patients with Parkinson’s disease (PD) and
other neurodegenerative disorders to evaluate the effect of transcranial
applications of AC pulsed electromagnetic fields (EMFs) in the
picotesla flux density on visuoconstructional skills. A seminal
observation is reported in 5 medicated PD patients who demonstrated
reversal of spontaneous drawing direction of the bicycle after they
received a series of transcranial treatments with AC pulsed EMFs. In 3
patients reversal of the bicycle drawing direction was observed shortly
after the administration of pulsed EMFs while in 2 patients these
changes were observed within a time lag ranging from several weeks to
months. All patients also demonstrated a dramatic clinical response to
the administration of EMFs. These findings are intriguing because
changes in drawing direction do not occur spontaneously in normal
individuals as a result of relateralization of cognitive functions. This
report suggests that administration of AC pulsed EMFs may induce in
some PD patients changes in hemispheric dominance during processing of a
visuoconstructional task and that these changes may be predictive of a
particularly favourable response to AC pulsed EMFs therapy.
Int J Neurosci. 1998 May;94(1-2):41-54.
Transcranial AC pulsed applications of weak electromagnetic fields
reduces freezing and falling in progressive supranuclear palsy: a case
report.
Sandyk R.
Department of Neuroscience, Institute for Biomedical Engineering and
Rehabilitation Services, Touro College, Dix Hills, NY 11746, USA.
Freezing is a common and disabling symptom in patients with
Parkinsonism. It affects most commonly the gait in the form of start
hesitation and sudden immobility often resulting in falling. A higher
incidence of freezing occurs in patients with progressive supranuclear
palsy (PSP) which is characterized clinically by a constellation of
symptoms including supranuclear ophthalmoplegia, postural instability,
axial rigidity, dysarthria, Parkinsonism, and pseudobulbar palsy.
Pharmacologic therapy of PSP is currently disappointing and the disease
progresses relentlessly to a fatal outcome within the first decade after
onset. This report concerns a 67 year old woman with a diagnosis of PSP
in whom freezing and frequent falling were the most disabling symptoms
of the disease at the time of presentation. Both symptoms, which were
rated 4 on the Unified Parkinson Rating Scale (UPRS) which grades
Parkinsonian symptoms and signs from 0 to 4, with 0 being normal and 4
being severe symptoms, were resistant to treatment with dopaminergic
drugs such as levodopa, amantadine, selegiline and pergolide mesylate as
well as with the potent and highly selective noradrenergic reuptake
inhibitor nortriptyline. Weekly transcranial applications of AC pulsed
electromagnetic fields (EMFs) of picotesla flux density was associated
with approximately 50% reduction in the frequency of freezing and about
80-90% reduction in frequency of falling after a 6 months follow-up
period. At this point freezing was rated 2 while falling received a
score of 1 on the UPRS. In addition, this treatment was associated with
an improvement in Parkinsonian and pseudobulbar symptoms with the
difference between the pre-and post EMF treatment across 13 measures
being highly significant (p < .005; Sign test). These results suggest
that transcranial administration AC pulsed EMFs in the picotesla flux
density is efficacious in the treatment of PSP.
J Neurosci. 1998 Feb;93(1-2):43-54.
Reversal of a body image disorder (macrosomatognosia) in Parkinson’s disease by treatment with AC pulsed electromagnetic fields.
Sandyk R.
Department of Neuroscience, Institute for Biomedical Engineering and
Rehabilitation Services of Touro College, Dix Hills, NY 11746, USA.
Macrosomatognosia refers to a disorder of the body image in which the
patient perceives a part or parts of his body as disproportionately
large. Macrosomatognosia has been associated with lesions in the
parietal lobe, particularly the right parietal lobe, which integrates
perceptual-sensorimotor functions concerned with the body image. It has
been observed most commonly in patients with paroxysmal cerebral
disorders such as epilepsy and migraine. The Draw-a-Person-Test has been
employed in neuropsychological testing to identify disorders of the
body image. Three fully medicated elderly Parkinsonian patients who
exhibited, on the Draw-a-Person Test, macrosomatognosia involving the
upper limbs are presented. In these patients spontaneous drawing of the
figure of a man demonstrated disproportionately large arms. Furthermore,
it was observed that the arm affected by tremor or, in the case of
bilateral tremor, the arm showing the most severe tremor showed the
greatest abnormality. This association implies that dopaminergic
mechanisms influence neuronal systems in the nondominant right parietal
lobe which construct the body image. After receiving a course of
treatments with AC pulsed electromagnetic fields (EMFs) in the picotesla
flux density applied transcranially, these patients’ drawings showed
reversal of the macrosomatognosia. These findings demonstrate that
transcranial applications of AC pulsed EMFs affect the neuronal systems
involved in the construction of the human body image and additionally
reverse disorders of the body image in Parkinsonism which are related to
right parietal lobe dysfunction.
Int J Neurosci. 1997 Nov;92(1-2):63-72.
Speech impairment in Parkinson’s disease is improved by transcranial application of electromagnetic fields.
Sandyk R.
Department of Neuroscience, Touro College, Dix Hills, NY 11746, USA.
A 52 year old fully medicated physician with juvenile onset
Parkinsonism experienced 4 years ago severe “on-off” fluctuations in
motor disability and debilitating speech impairment with severe
stuttering which occurred predominantly during “on-off” periods. His
speech impairment improved 20%-30% when sertraline (75 mg/day), a
serotonin reuptake inhibitor, was added to his dopaminergic medications
which included levodopa, amantadine, selegiline and pergolide mesylate. A
more dramatic and consistent improvement in his speech occurred over
the past 4 years during which time the patient received, on a fairly
regular basis, weekly transcranial treatments with AC pulsed
electromagnetic fields (EMFs) of picotesla flux density. Recurrence of
speech impairment was observed on several occasions when regular
treatments with EMFs were temporarily discontinued. These findings
demonstrate that AC pulsed applications of picotesla flux density EMFs
may offer a nonpharmacologic approach to the management of speech
disturbances in Parkinsonism. Furthermore, this case implicates cerebral
serotonergic deficiency in the pathogenesis of Parkinsonian speech
impairment which affects more than 50% of patients. It is believed that
pulsed applications of EMFs improved this patient’s speech impairment
through the facilitation of serotonergic transmission which may have
occurred in part through a synergistic interaction with sertraline.
Int J Neurosci. 1997 Oct;91(3-4):189-97.
Treatment with AC pulsed electromagnetic fields improves the response to levodopa in Parkinson’s disease.
Sandyk R.
Department of Neuroscience, Touro College, Dix Hills, NY 11746, USA.
A 52 year old fully medicated Parkinsonian patient with severe
disability (stage 4 on the Hoehn & Yahr disability scale) became
asymptomatic 10 weeks after he received twice weekly transcranial
treatments with AC pulsed electromagnetic fields (EMFs) of picotesla
flux density. Prior to treatment with EMFs, his medication (Sinemet CR)
was about 50% effective and he experienced end-of-dose deterioration and
diurnal-related decline in the drug’s efficacy. For instance, while his
morning medication was 90% effective, his afternoon medication was only
50% effective and his evening dose was only 30% effective. Ten weeks
after introduction of treatment with EMFs, there was 40% improvement in
his response to standard Sinemet medication with minimal change in its
efficacy during the course of the day or evening. These findings
demonstrate that intermittent, AC pulsed applications of picotesla flux
density EMFs improve Parkinsonian symptoms in part by enhancing the
patient’s response to levodopa. This effect may be related to an
increase in the capacity of striatal DA neurons to synthesize, store and
release DA derived from exogenously supplied levodopa as well as to
increased serotonin (5-HT) transmission which has been shown to enhance
the response of PD patients to levodopa. Since decline in the response
to levodopa is a phenomenon associated with progression of the disease,
this case suggests that intermittent applications of AC pulsed EMFs of
picotesla flux density reverse the course of chronic progressive PD.
Int J Neurosci. 1997 Sep;91(1-2):57-68.
Reversal of cognitive impairment in an elderly parkinsonian patient
by transcranial application of picotesla electromagnetic fields.
Sandyk R.
Department of Neuroscience, Touro College, Dix Hills, NY 11746, USA.
A 74 year old retired building inspector with a 15 year history of
Parkinson’s disease (PD) presented with severe resting tremor in the
right hand, generalized bradykinesia, difficulties with the initiation
of gait with freezing, mental depression and generalized cognitive
impairment despite being fully medicated. Testing of constructional
abilities employing various drawing tasks demonstrated drawing
impairment compatible with severe left hemispheric dysfunction. After
receiving two successive transcranial applications, each of 20 minutes
duration, with AC pulsed electromagnetic fields (EMFs) of 7.5 picotesla
flux density and frequencies of 5Hz and 7Hz respectively, his tremor
remitted and there was dramatic improvement in his drawing performance.
Additional striking improvements in his drawing performance occurred
over the following two days after he continued to receive daily
treatments with EMFs. The patient’s drawings were subjected to a
Reliability Test in which 10 raters reported 100% correct assessment of
pre- and post drawings with all possible comparisons (mean 2 = 5.0; p
< .05). This case demonstrates in PD rapid reversal of drawing
impairment related to left hemispheric dysfunction by brief transcranial
applications of AC pulsed picotesla flux density EMFs and suggests that
cognitive deficits associated with Parkinsonism, which usually are
progressive and unaffected by dopamine replacement therapy, may be
partly reversed by administration of these EMFs. Treatment with
picotesla EMFs reflects a “cutting edge” approach to the management of
cognitive impairment in Parkinsonism.
Int J Neurosci. 1997 Jun;90(1-2):75-86.
Treatment with weak electromagnetic fields restores dream recall in a parkinsonian patient.
Sandyk R.
Department of Neuroscience, Institute for Biomedical Engineering and
Rehabilitation Services, Touro College, Dix Hills, NY 11746, USA.
Absent or markedly reduced REM sleep with cessation of dream recall
has been documented in numerous neurological disorders associated with
subcortical dementia including Parkinson’s disease, progressive
supranuclear palsy and Huntington’s chorea. This report concerns a 69
year old Parkinsonian patient who experienced complete cessation of
dreaming since the onset of motor disability 13 years ago. Long term
treatment with levodopa and dopamine (DA) receptor agonists
(bromocriptine and pergolide mesylate) did not affect dream recall.
However, dreaming was restored after the patient received three
treatment sessions with AC pulsed picotesla range electromagnetic fields
(EMFs) applied extracranially over three successive days. Six months
later, during which time the patient received 3 additional treatment
sessions with EMFs, he reported dreaming vividly with intense colored
visual imagery almost every night with some of the dreams having sexual
content. In addition, he began to experience hypnagogic imagery prior to
the onset of sleep. Cessation of dream recall has been associated with
right hemispheric dysfunction and its restoration by treatment with EMFs
points to right hemispheric activation, which is supported by
improvement in this patient’s visual memory known to be subserved by the
right temporal lobe. Moreover, since DA neurons activate REM sleep
mechanisms and facilitate dream recall, it appears that application of
EMFs enhanced DA activity in the mesolimbic system which has been
implicated in dream recall. Also, since administration of pineal
melatonin has been reported to induce vivid dreams with intense colored
visual imagery in normal subjects and narcoleptic patients, it is
suggested that enhanced nocturnal melatonin secretion was associated
with restoration of dream recall in this patient. These findings
demonstrate that unlike chronic levodopa therapy, intermittent pulsed
applications of AC picotesla EMFs may induce in Parkinsonism
reactivation of reticular-limbic-pineal systems involved in the
generation of dreaming.
Int J Neurosci. 1996 Nov;87(3-4):209-17.
Brief communication: electromagnetic fields improve visuospatial performance and reverse agraphia in a parkinsonian patient.
Sandyk R.
Department of Neuroscience, Touro College, Dix Hills, NY 11746, USA.
A 73 year old right-handed man, diagnosed with Parkinson’s disease
(PD) in 1982, presented with chief complaints of disabling resting and
postural tremors in the right hand, generalized bradykinesia and
rigidity, difficulties with the initiation of gait, freezing of gait,
and mild dementia despite being fully medicated. On neuropsychological
testing the Bicycle Drawing Test showed cognitive impairment compatible
with bitemporal and frontal lobe dysfunction and on attempts to sign his
name he exhibited agraphia. After receiving two successive treatments,
each of 20 minutes duration, with AC pulsed electromagnetic fields
(EMFs) of 7.5 picotesla intensity and 5 Hz frequency sinusoidal wave,
his drawing to command showed improvement in visuospatial performance
and his signature became legible. One week later, after receiving two
additional successive treatments with these EMFs each of 20 minutes
duration with a 7 Hz frequency sinusoidal wave, he drew a much larger,
detailed and visuospatially organized bicycle and his signature had
normalized. Simultaneously, there was marked improvement in Parkinsonian
motor symptoms with almost complete resolution of the tremors, start
hesitation and freezing of gait. This case demonstrates the dramatic
beneficial effects of AC pulsed picotesla EMFs on neurocognitive
processes subserved by the temporal and frontal lobes in Parkinsonism
and suggest that the dementia of Parkinsonism may be partly reversible.
Int J Neurosci. 1996 Mar;85(1-2):111-24.
Freezing of gait in Parkinson’s disease is improved by treatment with weak electromagnetic fields.
Sandyk R.
NeuroCommunication Research Laboratories, Danbury, CT 06811, USA.
Freezing, a symptom characterized by difficulty in the initiation and
smooth pursuit of repetitive movements, is a unique and well known
clinical feature of Parkinson’s disease (PD). It usually occurs in
patients with long duration and advanced stage of the disease and is a
major cause of disability often resulting in falling. In PD patients
freezing manifests most commonly as a sudden attack of immobility
usually experienced during walking, attempts to turn while walking, or
while approaching a destination. Less commonly it is expressed as arrest
of speech or handwriting. The pathophysiology of Parkinsonian freezing,
which is considered a distinct clinical feature independent of
akinesia, is poorly understood and is believed to involve abnormalities
in dopamine and norepinephrine neurotransmission in critical motor
control areas including the frontal lobe, basal ganglia, locus coeruleus
and spinal cord. In general, freezing is resistant to pharmacological
therapy although in some patients reduction or increase in levodopa dose
may improve this symptom. Three medicated PD patients exhibiting
disabling episodes of freezing of gait are presented in whom brief,
extracerebral applications of pulsed electromagnetic fields (EMFs) in
the picotesla range improved freezing. Two patients had freezing both
during “on” and “off” periods while the third patient experienced random
episodes of freezing throughout the course of the day. The effect of
each EMFs treatment lasted several days after which time freezing
gradually reappeared, initially in association with “off” periods. These
findings suggest that the neurochemical mechanisms underlying the
development of freezing are sensitive to the effects of EMFs, which are
believed to improve freezing primarily through the facilitation of
serotonin (5-HT) neurotransmission at both junctional (synaptic) and
nonjunctional neuronal target sites.
Int J Neurosci. 1998 Apr;93(3-4):239-50.
Treatment with AC pulsed electromagnetic fields normalizes the
latency of the visual evoked response in a multiple sclerosis patient
with optic atrophy.
Sandyk R.
Department of Neuroscience at the Institute for Biomedical
Engineering and Rehabilitation Services of Touro College, Dix Hills, NY
11746, USA.
Visual evoked response (VER) studies have been utilized as supportive
information for the diagnosis of multiple sclerosis (MS) and may be
useful in objectively monitoring the effects of various therapeutic
modalities. Delayed latency of the VER, which reflects slowed impulse
transmission in the optic pathways, is the most characteristic
abnormality associated with the disease. Brief transcranial applications
of AC pulsed electromagnetic fields (EMFs) in the picotesla flux
density are efficacious in the symptomatic treatment of MS and may also
reestablish impulse transmission in the optic pathways. A 36 year old
man developed an attack of right sided optic neuritis at the age of 30.
On presentation he had blurring of vision with reduced acuity on the
right and fundoscopic examination revealed pallor of the optic disc. A
checkerboard pattern reversal VER showed a delayed latency to right eye
stimulation (P100 = 132 ms; normal range: 95-115 ms). After he received
two successive applications of AC pulsed EMFs of 7.5 picotesla flux
density each of 20 minutes duration administered transcranially, there
was a dramatic improvement in vision and the VER latency reverted to
normal (P100= 107 ms). The rapid improvement in vision coupled with the
normalization of the VER latency despite the presence of optic atrophy,
which reflects chronic demyelination of the optic nerve, cannot be
explained on the basis of partial or full reformation of myelin. It is
proposed that in MS synaptic neurotransmitter deficiency is associated
with the visual impairment and delayed VER latency following optic
neuritis and that the recovery of the VER latency by treatment with
pulsed EMFs is related to enhancement of synaptic neurotransmitter
functions in the retina and central optic pathways. Recovery of the VER
latency in MS patients may have important implications with respect to
the treatment of visual impairment and prevention of visual loss.
Specifically, repeated pulsed applications of EMFs may maintain impulse
transmission in the optic nerve and thus potentially sustain its
viability.
Int J Neurosci, 66(3-4):209-35 1992 Oct
Magnetic fields in the therapy of parkinsonism.
Sandyk R NeuroCommunication Research Laboratories, Danbury, CT 06811.
In a recent Editorial published in this Journal, I presented a new
and revolutionary method for the treatment of Parkinson’s disease (PD). I
reported that extracranial treatment with picoTesla magnetic fields
(MF) is a highly effective, safe, and revolutionary modality in the
symptomatic management of PD. My conclusion was based on experience
gained following the successful treatment of over 20 Parkinsonian
patients, two of whom had levodopa-induced dyskinesias. None of the
patients developed side effects during a several month period of
follow-up. In the present communication, I present two reports. The
first concerns four Parkinsonian patients in whom picoTesla MF produced a
remarkable and sustained improvement in disability. Three of the
patients had idiopathic PD and the fourth patient developed a
Parkinsonian syndrome following an anoxic episode. In all patients,
treatment with MF was applied as an adjunct to antiParkinsonian
medication. The improvement noted in these patients attests to the
efficacy of picoTesla MF as an additional, noninvasive modality in the
therapy of the disease. The second report concerns two demented
Parkinsonian patients in whom treatment with picoTesla MF rapidly
reversed visuospatial impairment as demonstrated by the Clock Drawing
Test. These findings demonstrate, for the first time, the efficacy of
these MF in the amelioration of cognitive deficits in Parkinson’s
disease. Since Alzheimer’s pathology frequently coexists with the
dementia of Parkinsonism, these observations underscore the potential
efficacy of picoTesla MF in the treatment of dementias of various
etiologies.
The effect of low-intensity lases light (0.2 mW/cm2, 632.8 nm,
exposure time 1 min) or centimeter waves (8.15-18 GHz, 1 W/cm2, exposure
time 1 h) on PhosphoSAPK/JNK production in mice lymphocytes was
investigated. Normal isolated spleen lymphocytes or cells incubated
previously with geldanamycin, an inhibitor of heat shock protein 90
(HSP90), were used in the experiments. A significant stimulation of
PhosphoSAPK/JNK production in lymphocytes after treatment with laser
light or microwaves has been shown in both cell models. It was proposed
that the activation of SAPK/JNK signal pathway plays one of the central
roles in cellular stress response to low-power nonionizing radiation.
Biofizika. 2008 Jan-Feb;53(1):93-9.
The role of heat shock proteins HSP90 in the response of immune cells to centimeter microwaves.
The effects of low-level electromagnetic waves (8.15-18 GHz, 1
microW/cm2, 1 h) on the production of heat shock proteins, several
cytokines, and nitric oxide in isolated mouse macrophages and
lymphocytes were examined both under normal conditions and after the
treatment of the cells with geldanamycin (GA), a depressor of activity
of the heat shock protein 90 (Hsp90). The irradiation of cells without
GA induced the production of Hsp70, nitric oxide (NO), interleukin-1beta
(IL-1beta), interleukin-10 (IL-10), and the tumor necrosis factor
-alpha (TNF-alpha). No changes in the production of Hsp90 in irradiated
cells were observed, but intracellular locations of Hsp25 and Hsp70
altered. The preliminary treatment of cells with GA did not remove the
effects of microwaves: in these conditions, the synthesis of all
cytokines tested, nitric oxide, as well as total and membrane amount of
Hsp70, and the amount of Hsp25 in the cytoplasm and cytoskeleton
increased. Moreover, the exposure of cells incubated with GA resulted in
the reduction of Hsp90-alpha production.
Biofizika. 2007 Sep-Oct;52(5):938-46.
Effects of centimeter waves on the immune system of mice in endotoxic shock.
The effects of centimeter waves (8.15-18 GHz, 1 microW/cm2, 1 h daily
for 10 days; MW) on the production of the tumor necrosis factor alpha,
interleukin-lalpha, interleukin-1beta, interleukin-2, and the expression
of interleukin-6, interleukin-10, interferon-gamma, nitric oxide and
HSP27, HSP72 and HSP90alpha in mice irradiated before or after LPS
injection were studied. An acute endotoxic model was produced by a
single LPS injection. The effects of microwaves on nitric oxide,
interleukin-6, tumor necrosis factor-alpha, and interferon-gamma were
dependent on the functional status of exposed animals. Thus, an exposure
of healthy mice to microwaves for 10 days was followed by a decrease in
nitric oxide and interferon-gamma production, and an increase in the
production of the tumor necrosis factor-alpha and interleukin-6. On the
contrary, an exposure to MW before intoxication resulted in an increase
in the synthesis of nitric oxide and interferon-gamma as well as a
decrease in the concentration of the tumor necrosis factor-alpha and
interleukin-6 in blood of mice in endotoxic shock. When microwave
exposure was used after LPS injection, it did not provide any protective
effect, and preliminary irradiation enhanced the resistance of the
organism to endotoxic shock.
Biofizika. 2007 Sep-Oct;52(5):888-92.
The role of transcription factors in the response of mouse lymphocytes to low-level electromagnetic and laser radiations.
The effects of low-intensity laser radiation (LILR, 632.8 nm, 0.2
mW/cm2) and low-intensity electromagnetic waves (LIEW, 8.15 – 18 GHz, 1
MW/cm2) on the production of transcription factors in lymphocytes from
NMRI male mice were examined. The total level of NF-KB and its
phosphorylated metabolite Phospho-NF-kappaB, as well as the regulatory
protein IkappaB-alpha were determined in spleen lymphocytes subjected to
laser or microwave radiations. The proteins were determined by
immunoblotting. Laser light induced a lowering in the level of NF-kappaB
and IkappaB-alpha. By contrast, irradiation with electromagnetic waves
resulted in a significant increase in the amount of NF-kappaB and
IkappaB-alpha. The phosphorylated form of NF-kappaB did not noticeably
change under either of the two kinds of radiation. The results showed
that electromagnetic waves activate the production of both NF-kappaB and
the regulatory protein IkappaB-alpha and these data confirm the stress
character of the response of spleen lymphocytes to low-level microwaves
of the centimeter range.
Biofizika. 2004 May-Jun;49(3):545-50.
A comparison of the effects of millimeter and centimeter waves on tumor necrosis factor production in mouse cells.
The effects of millimeter (40 GHz) and centimeter (8.15-18.00 GHz)
low-intensity waves on the production of tumor necrosis factor (TNE) in
macrophages and lymphocytes from exposed mice as well as in exposed
isolated cells were compared. It was found that the dynamics of TNF
secretory activity of cells varies depending on the frequency and
duration of exposure. The application of millimeter waves induced a
nonmonotonous course of the dose-effect curve for TNF changes in
macrophages and splenocytes. Alternately, a stimulation and a decrease
in TNF production were observed following the application of millimeter
waves. On the contrary, centimeter waves provoked an activation in
cytokine production. It is proposed that, in contrast to millimeter
waves, the single application of centimeter waves to animals (within 2
to 96 h) or isolated cells (within 0.5 to 2.5 h) induced a much more
substantial stimulation of immunity.
Biofizika. 2003 May-Jun;48(3):511-20.
Effect of low intensity of electromagnetic radiation in the
centimeter and millimeter range on proliferative and cytotoxic activity
of murine spleen lymphocytes.
[Article in Russian]
Oga? VB, Novoselova EG, Fesenko EE.
Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia.
Abstract
It was found that single total-body exposure to electromagnetic
centimeter waves (8.15-18 GHz, 1 microW/cm2, 5 h) stimulated the
proliferation of mouse T and B splenic lymphocytes. The same effects
were observed upon in vivo treatment of rats for 5 h with millimeter
waves (42.2 GHz, amplitude modulation 10 Hz, 1 microW/cm2). The
whole-body irradiation with centimeter or millimeter waves did not cause
any significant changes in natural activity of killer cells. The
cellular responses induced by the irradiation of isolated animal cells
in vitro did not coincide with those revealed after the total-body
irradiation of animals. Thus, the in vitro irradiation of natural killer
cells to millimeter waves for 1 h increased their cytotoxic activity
whereas, after treatment to centimeter waves for the same time, the
activity of killer cells did not change. On the contrary, irradiation of
T and B lymphocytes with millimeter waves (42.2 GHz, amplitude
modulation 10 Hz, 1 microW/cm2, 1 h) suppressed the blasttransformation
of cells. The results show a higher immunostimulative potential of
centimeter waves as compared to millimeter waves.
Biofizika. 2003 Mar-Apr;48(2):281-8.
Immunocorrective effect of low intensity radiation of ultrahigh frequency on carcinogenesis in mice.
Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia.
Abstract
The effect of low-intensity centimeter electromagnetic waves (8.15-18
GHz, 1 microW/cm2, 1.5 h daily, 20 days) on the production of tumor
necrosis factor, intreleukin-2, and interleukin-3 and the expression of
the heat shock protein 72 in healthy and tumor-bearing mice was
measured. A significant increase in tumor necrosis factor production and
a slight reduction of interleukin-2 concentration were observed after
exposure to microwaves; we consider these effects as adaptive response.
The interleukin-3 production in healthy mice was not affected by
microwaves. Low-intensity centimeter waves induced antitumoral
resistance in tumor-bearing mice. Thus, exposure of tumor-bearing mice
led to a significant rise in the tumor necrosis factor production and
the normalization of both interleukin-2 and interleukin-3 concentration.
We assume that the significant immunomodulating effect of low-density
centimeter microwaves can be used for immunocorrection and suppression
of tumor growth.
Biofizika. 2002 Mar-Apr;47(2):376-81.
Immunomodulating effect of electromagnetic waves on production of
tumor necrosis factor in mice with various rates of neoplasm growth.
Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia.
Abstract
The effects of low-density centimeter waves (8.15-18 GHz, 1
microW/cm2, 1 h daily for 14 days; MW) on tumor necrosis factor
production in macrophages of mice with different growth rate of a cancer
solid model produced after hypodermic injection of Ehrlich carcinoma
ascites cells into hind legs were studied. After irradiation, an
increase in the concentration of tumor necrosis factor in
immunocompetent cells of healthy and, specially, of tumor-bearing
animals was observed; and the effect of stimulation was higher upon
exposure of mice carrying rapidly growing tumors. We suggest that the
significant immunomodulating effect of low-density microwaves can be
utilized for tumor growth suppression.
Biofizika. 2002 Jan-Feb;47(1):78-82.
Effect of electromagnetic waves in the centimeter range on the
production of tumor necrosis factor and interleukin-3 in immunized mice.
Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia.
Abstract
The effect of prolonged treatment with weak microwaves on the
production of tumor necrosis factor and interleukin-3 in peritoneal
macrophages and T cells of male NMRI mice twice immunized by
affinity-purified carboanhydrase was studied. Against the back ground of
a high titer of antibody production, a significant increase in the
production of tumor necrosis factor in peritoneal macrophages and
splenic T lymphocytes of immunized mice was revealed, and a much
stronger effect was observed for irradiated immunized animals. A
tendency to increased secretion of interleukin-3 for unirradiated and
irradiated immunized animals was found; in the latter group of animals,
the effect being more pronounced. The stimulation of production of the
cytokins, especially tumor necrosis factor, by combination of antigenic
stimulation and microwaves can be used in adjuvant therapy of various
immune diseases.
Biofizika. 2001 Jan-Feb;46(1):131-5.
Effect of centimeter microwaves and the combined magnetic field on
the tumor necrosis factor production in cells of mice with experimental
tumors.
Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia.
Abstract
The effect of fractionated exposure to low-intensity microwaves
(8.15-18 GHz, 1 microW/cm2, 1.5 h daily for 7 days) and combined weak
magnetic field (constant 65 1 microT; alternating–100 nT, 3-10 Hz) on
the production of tumor necrosis factor in macrophages of mice with
experimental solid tumors produced by transplantation of Ehrlich ascites
carcinoma was studied. It was found that exposure of mice to both
microwaves and magnetic field enhanced the adaptive response of the
organism to the onset of tumor growth: the production of tumor necrosis
factor in peritoneal macrophages of tumor-bearing mice was higher than
in unexposed mice.
Biofizika. 1999 Jul-Aug;44(4):737-41.
Stimulation of murine natural killer cells by weak electromagnetic waves in the centimeter range.
[Article in Russian]
Fesenko EE, Novoselova EG, Semiletova NV, Agafonova TA, Sadovnikov VB.
Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russia.
Abstract
Irradiation with electromagnetic waves (8.15-18 GHz, 1 Hz within, 1
microW/cm2) in vivo increases the cytotoxic activity of natural killer
cells of rat spleen. In mice exposed for 24-72 h, the activity of
natural killer cells increased by 130-150%, the increased level of
activity persisting within 24 h after the cessation of treatment.
Microwave irradiation of animals in vivo for 3.5 and 5 h, and a short
exposure of splenic cells in vitro did not affect the activity of
natural killer cells.
Biofizika. 1998 Nov-Dec;43(6):1132-3.
Stimulation of production of tumor necrosis factor by murine
macrophages when exposed in vio and in vitro to weak electromagnetic
waves in the centimeter range.
[Article in Russian]
Novoselova ET, Fesenko EE.
Abstract
Whole-body microwave sinusoidal irradiation of male NMRI mice,
exposure of macrophages in vitro, and preliminary irradiation of culture
medium with 8.15-18 GHz (1 Hz within) at a power density of 1
microW/cm2 caused a significant enhancement of tumor necrosis factor
production in peritoneal macrophages. The role of microwaves as a factor
interfering with the process of cell immunity is discussed.
Lik Sprava. 1992 Oct;(10):69-71.
The brain function of animals exposed to the action of centimeter electromagnetic waves.
[Article in Russian]
Smolia AL, Bezdol’naia IS.
Abstract
It was established that centimeter electromagnetic waves (EMW) are a
biologically active factor. Dynamic of changes of behavioural reactions
under the effect of EMW evidences instability of the functional state of
the brain EMW densities of 1000, 1500 mW/cm2 produce a response
characterized by inhibition of motor activity.
The immunological and hormonal effects of combined exposure to a
bitemporal ultrahigh-frequency electrical field and to decimeter waves
at different sites.
Bitemporal UHF electric field is shown to enhance glucocorticoid
adrenal function unlike inhibition of the thyroid function suppressing a
primary immune response (PIR) in the productive phase. The combined
exposure to bitemporal UHF electric field and decimeter waves of the
adrenals doubles glucocorticoid synthesis abolishing the inhibitory
action of the UHF therapy on thyroid function resultant in much more
suppressed PIR. Both modalities inhibit thymic production. Decimeter
waves alone are less effective. The exposure of the thyroid to decimeter
waves initiated PIR by 2.5-fold activation of medullar lymphocytes and
by a 80% increase in the thymic function. No response was achieved in
combined action on the thyroid of the electric field and decimeter
waves.
Tsitologiia. 1988 Nov;30(11):1345-9.
Effect of microwaves on the expression by thymocytes of various surface membrane markers.
[Article in Russian]
Evstropov VM, Melikhova ON.
Abstract
A study was made of the effects of microwave irradiation of different
intensity within decimeter and centimeter ranges in vitro on the
guinea-pig thymocyte-induced receptor expression to their own and rabbit
erythrocytes. Besides, effects of decimeter waves on mice
thymocyte-induced expression of Thy-1 antigen were studied. Microwaves
were found to modulate the thymocyte-induced expression of the membrane
surface markers under study.
Laser magnetotherapy after cataract extraction with implantation of intraocular lens.
[Article in Russian]
Maksimov VIu, Zakharova NV, Maksimova IS, Golushkov GA, Evseev SIu.
Effects of low-intensive laser and alternating magnetic field on the
course of the postoperative period were studied in patients with
exudative reaction after extracapsular cataract extraction with
implantation of intraocular lens (IOL). The results are analyzed for 148
eyes with early exudative reaction after IOL implantation (136 patients
aged 42-75 years). The patients were observed for up to 6 months. The
treatment efficiency was evaluated by the clinical picture of
inflammatory reaction, visual acuity, and results of biochemical
analysis of the lacrimal fluid (the ratio of lipid peroxidation products
to antioxidants in cell membrane). The course of the postoperative
period was more benign and recovery sooner in patients of the main group
in comparison with the control.
J Adv Res. 2017 Jan; 8(1): 45–53.
Published online 2016 Nov 21. doi: 10.1016/j.jare.2016.11.001
PMCID: PMC5144749
Pulsed magnetic field versus ultrasound in the
treatment of postnatal carpal tunnel syndrome: A randomized controlled
trial in the women of an Egyptian population
Abbreviations: CTS,
carpal tunnel syndrome; PEMF, pulsed electromagnetic magnetic field;
US, ultrasound; MMDL, median motor distal latency; MSDL, median sensory
distal latency; VAS, visual analogue scale; EMG, electromyography; MSDL,
median segmental sensory distal latency; NCSs, nerve conduction
studies; CTSQ, carpal tunnel syndrome questionnaire; MSCV, median
sensory conduction velocity; MMCV, median motor conduction velocity;
NCV, nerve conduction velocity
Keywords: Carpal tunnel syndrome, Electromagnetic field, Pulsed ultrasound, Pregnancy, Postnatal, Pain, Nerve conduction velocity
Abstract
The aim of this study was to compare
the effects of pulsed electromagnetic field versus pulsed ultrasound in
treating patients with postnatal carpal tunnel syndrome. The study was a
randomized, double-blinded trial. Forty postnatal female patients with
idiopathic carpal tunnel syndrome were divided randomly into two equal
groups. One group received pulsed electromagnetic field, with nerve and
tendon gliding exercises for the wrist, three times per week for four
weeks. The other group received pulsed ultrasound and the same wrist
exercises. Pain level, sensory and motor distal latencies and conduction
velocities of the median nerve, functional status scale and hand grip
strength were assessed pre- and post-treatment. There was a significant
decrease (P < 0.05) in pain level, sensory and motor distal latencies of the median nerve, and significant increase (P < 0.05)
in sensory and motor conduction velocities of the median nerve and hand
grip strength in both groups, with a significant difference between the
two groups in favour of pulsed electromagnetic field treatment.
However, the functional status scale showed intergroup no significant
difference (P > 0.05). In conclusion, while the symptoms
were alleviated in both groups, pulsed electromagnetic field was more
effective than pulsed ultrasound in treating postnatal carpal tunnel
syndrome.
Introduction
Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy, which results from median nerve compression [1], [2]. Prevalence of CTS in the general population is 3.8% when diagnosed clinically and 2.7% when diagnosed neurophysiologically [3]. Women are more susceptible to CTS, with a 70% incidence rate, especially middle-aged women [4].
CTS is a common complaint during pregnancy, as the existing data show
the prevalence rate of CTS during pregnancy to be as high as 62% [5], [6].
CTS usually develops in the second half of pregnancy because of fluid
retention, due to decreased venous circulation, which causes swelling of
tissues [7].
Another factor that increases CTS rates during pregnancy is hormonal
alterations, including increased oestrogen, aldosterone, and cortisol
levels. In addition, increased levels of prolactin are strongly
correlated with CTS symptoms worsening during the night, which coincides
with the prolactin circadian rhythm [8].
Further, release of relaxin can lead to relaxation of the transverse
carpal ligament, leading to its flattening, and subsequent compression
of the median nerve [9].
Although most pregnant women experience symptom relief following
delivery, a significant percentage continue to have some level of
complaint up to three years after giving birth [10].
The most typical symptoms of CTS are numbness and tingling in the
distribution of the median nerve, burning sensation, pain, as well as
loss of grip strength and dexterity [11].
There are several therapeutic options for patients with CTS
depending on various factors, including the stage of the disease, the
severity of the symptoms, and patients’ preferences. Non-surgical
intervention is recommended as the first-line treatment, in cases of
mild to moderate CTS. Surgery is reserved for patients with severe CTS,
and those who have experienced failure of conservative treatment. The
same treatment strategy is used for postnatal patients with CTS [12].
Non-surgical treatment modalities used for the management
of CTS are numerous and include medical and physical therapy. Primary
physical therapy interventions are splinting, nerve and tendon gliding
exercises, acupuncture, low-level laser, and ultrasound with or without
phonophoresis. Electromagnetic therapy is less widely used than these
other therapies as currently there is limited research into the effects
of electromagnetic therapy on CTS [13].
To our knowledge, no study has yet
compared magnetic field therapy (which has limited research supporting
its use), and ultrasound (which is among the most common treatments for
CTS), in postnatal women, a population with a high incidence of CTS.
Thus, our aim was to investigate which modality gives better results in
treating CTS.
Subjects and methods
Subjects
The initial sample was pregnant women
clinically diagnosed with CTS in their third trimester; they were
recruited and screened for eligibility in this study (Fig. 1). After
the approval of the Research Ethical Committee P.T.REC/012/001211, of
the Faculty of Physical Therapy, Cairo University, and clinical trial
registration in Clinicaltrial.gov with identifier number NCT02745652,
subjects were selected from the obstetric, orthopaedic and neurological
outpatient clinics in Al Kasr Al Ani Hospitals and the Faculty of
Physical Therapy, Cairo University. Patients were advised to wear a
hand splint until giving birth and come back three months after
delivery for baseline measures and initiation of treatment.
An informed consent form was signed by each subject prior to starting the study.
Participants were randomly assigned into two groups using a random
number table, and the selection process was performed by a third party
not involved in the research. The study was double-blinded and the
participants were randomized into the following two equal groups: group A
(n = 20), who received pulsed electromagnetic field (PEMF), and group B
(n = 20), who received pulsed ultrasound (US). Both groups received
nerve and tendon gliding exercises for 5 min. Treatment in both groups
was conducted for four weeks, three times per week with a total of 12
treatment sessions. The study started in May 2014 and ended in March
2015.
The following inclusion and exclusion criteria were designed to select a relatively homogeneous group of patients.
Inclusion criteria were unilateral affection, mild to
moderate CTS with positive electro-diagnostic findings of prolonged
median motor distal latency (MMDL) above 4 ms, and prolonged median
sensory distal latency (MSDL) above 3.5 ms [14].
Positive both or either Phalen’s and Tinel’s tests, both tests have
high percentages of sensitivity (73% and 67% respectively), and
specificity (40% and 30% respectively), for CTS diagnosis [15]. Lastly, subjects reported pain intensity of more than five on the visual analogue scale (VAS).
Exclusion criteria for the study were electro-neurographic and clinical signs of axonal degeneration of the median nerve [14],
and orthopaedic or neurological disorders of the neck or the upper limb
such as cervical radiculopathy, pronator teres syndrome or double crush
syndrome. Patients with pre-existing CTS before their most recent
pregnancy, current pregnancy, diabetic neuropathy and thoracic outlet
syndrome were excluded. Further exclusion criteria were wasting of
thenar muscles, ulnar neuropathy, rheumatoid arthritis, previous
fractured carpal bone, and previous surgery in the forearm, especially
transverse ligament release.
Assessment was done before and after four weeks of intervention for both groups using the following.
1.
Visual Analogue Scale (VAS). It is considered a valid way of assessing pain, and allows graphic representation and numerical analysis of the collected data.
2.
Computerized Electromyography (EMG). Tonnies neuroscreen
plus (version 1.59 Art, No: 780918 Erich Jaeger, Inc. Hoechberg,
Germany) with Food and Drug Administration (FDA) registration No.
9615102, was used for assessment of the nerve conduction studies (NCSs).
MMDL was recorded through wrist stimulation, and proximal latency
through elbow stimulation. Both patient’s and room temperature were
monitored so as not to affect the recording procedures, and the
patient’s skin was cleaned with alcohol 70% to decrease its resistance.
An active electrode (one-centimetre disc recording, either platinum or
disposable) was placed over the belly of the abductor pollicis brevis,
half the distance between the metacarpophalangeal joint of the thumb and
midpoint of the distal wrist crease, while a reference electrode was
placed on the distal phalanx of the thumb. For the wrist, a stimulation
electrode (cathode distal) was placed 2 cm proximal to the distal wrist
crease between the flexor carpi radialis and the palmaris longus
tendons. For the elbow, the stimulating electrode was applied at the
elbow crease, just medial to the biceps tendon. A ground electrode was
placed between the stimulating and recording electrodes using a Velcro
strap. Then median motor conduction velocity (MMCV) was calculated. MSDL
measuring points were the active electrode, which is a ring electrode
placed on the mid-portion of the proximal phalanx of the index finger
(or middle finger), and the reference electrode, which is a ring
electrode placed on the mid-portion of the middle phalanx of the index
finger, with 2.5 cm distance between the two poles (anode is proximal to
cathode). Wrist stimulation was performed at a distance of 14 cm from
the ring electrodes (anti-dromic). Percutaneous stimuli were delivered
until a supra-maximal response was obtained. Median sensory conduction
velocity (MSCV) was calculated on the basis of the latency and the
distance between the stimulating and recording electrode. For motor
studies, pulse duration was 0.2 ms, filter settings were 10–10,000 Hz,
sweep speed was 2–5 m/s per division, and sensitivity was 1000–5000 ?v
per division. For sensory studies, pulse duration was 0.05 ms, filter
settings were 20–2000 Hz, sweep speed was 1–2 m/s per division, and sensitivity was 5–10 ?v per division [16].
3.
Hand grip dynamometer. A hydraulic hand dynamometer
(“SH5001” SAEHAN Corporation, Masan, South Korea) was used to detect
hand grip strength and for measuring the maximum isometric strength of
the hand and forearm muscles in kilograms (kg). It is a simple and
commonly used test of general strength level [17]. The average of three trials of the affected hand was recorded.
4.
Functional status scale. This is a part of the Carpal Tunnel Syndrome Questionnaire (CTSQ) [18].
It asks about eight functional activities such as writing, buttoning of
clothes, gripping of a telephone handle. Each functional activity is
scaled from one to five, where one means none or never and five means
very severe.
5.
Phalen test. The result of the test is positive if
numbness or paresthesia develops in the median nerve distribution after
flexion of the wrist for 60 s.
6.
Tinel test. The test is positive if numbness develops in
the median nerve distribution after tapping on the volar aspect of the
wrist over the course of the median nerve.
Treatment sessions occurred three times per week for four weeks, as follows.
1.
All patients in both groups performed nerve and tendon gliding and median nerve gliding exercises [19].
Tendon gliding exercises were done in five steps (straight, hook, fist,
table top and straight fist). Median nerve gliding exercises were
performed in six steps (fist, straight, wrist extension, wrist and
fingers extension, supination, and gentle stretch of thumb). During
these exercises, the neck and the shoulder were in a neutral position,
and the elbow was in supination and 90 degrees of flexion. At each step,
the patient maintained each position for five seconds, for 10
repetitions at each session. These exercises were performed in each
session, three times/week for four weeks.
2.
PEMF Group treatment protocol used Pulsed Magnetic Field (automatic
PTM Quattro PRO, code # F9020079, ASA S.r.l Company, Arcugnano [VI],
Italy). This is an ASA magnetic device for magneto-therapy,
which has an appliance, motorized bed, and applicable large solenoids,
which can be moved to four different positions according to the
treatment area, and an additional small solenoid of 30 cm diameter for
hand treatment. Patients in this group received pulsed electromagnetic
field therapy at frequency 50 Hz and intensity 80 gauss for
30 min. The patient was in sitting position, while the forearm rested on
the bed inside the solenoid in a supination position. Safety was
evaluated in the PEMF group by recording adverse effects, both those
that lead to cessation of treatment (dropouts), and those that did not.
3.
US Group treatment protocol used Therapeutic Ultrasound (Phyaction
190 I, Uniphy P.O. Box 558.5600 AN Eindhoven, Netherlands). Pulsed mode
US was applied over the volar surface of the forearm (the carpal tunnel
area) for 15 min per session with a frequency of 1 MHz and intensity of 1.0 W/cm2[20].
Outcome measures
Outcomes recorded before and after
the four-week treatment course were pain intensity, median motor distal
latency (MMDL) and median sensor distal latency (MSDL), Median sensory
conduction velocity (MSCV), median motor conduction velocity (MMCV), the
Tinel’s test, Phalen’s test, hand grip strength and the functional
status scale.
Statistical analysis
All the collected data were
tabulated and imported into SPSS version 18 to calculate both
descriptive and inferential statistics. Descriptive analysis was
performed in terms of mean, standard deviation and percentages. While
inferential statistics were in the form of a Paired t-test to
determine the difference within each group, an unpaired t-test was done
to determine the difference in pre- and post-treatment between both
groups. In addition, nonparametric statistics in the form of the
Mann–Whitney test was performed to compare intergroup differences for
the Tinel’s sign, Phalen’s test, VAS and functional status scale while
intragroup differences were done by Kolmogorov Smirnov test.
Furthermore, the work demographic data were tested by Chi-square test.
Statistical significance was established at the conventional (P < 0.05) with confidence interval (CI) of 95%.
Results
This study included 55 pregnant women
with unilateral idiopathic CTS. Of the 55 patients, five did not fulfil
the inclusion criteria and were excluded from the study. The exclusions
were due to pre-pregnancy diabetes mellitus (two cases), severe CTS with
delayed MMDL equalling 9.5 ms (one case), and another two cases
diagnosed with thoracic outlet syndrome. In addition, another five
patients experienced greatly alleviated CTS symptoms after giving birth
and chose to withdraw from the study. These patients all experienced
significant postnatal weight loss with a mean difference of 5.5 kg (P = 0.0001).
Lastly, one patient did not return at the three-month follow-up. During
the study, there were four additional cases lost to follow-up, two
cases from each treatment group. Thus, the final sample consisted of 40
patients, 20 in each group. The demographic data for both groups were
tested pre-intervention to confirm homogeneity and no significant
difference was found (P > 0.05) (Table 1).
Table 1
Demographic data of subjects in both groups.
The comparisons of intragroup mean values of all
variables in both groups, before and after end of the treatment showed a
significant intragroup improvement in both groups (Table 2). Furthermore, Table 3 summarizes the intragroup differences for the Tinel’s test, Phalen’s test, VAS, and the functional status scale.
Table 2
Comparison of mean pre and post treatment in both groups.
Table 3
Tinel’s and Phalen’s tests, VAS, and functional status scale in both groups.
Clinical outcomes
Pain (VAS), showed significant improvement at the end of treatment in both groups, PEMF and US groups (P = 0.0001
and 0.021), respectively. PEMF leads to a 4.93 point reduction in VAS,
while the US group had a 1.3 point reduction with a significant
difference in the rate of improvement (P = 0.0001) in favour of PEMF (Table 3).
Pre-treatment, the Tinel’s test was positive in 15 (75%) of the PEMF
group and 17 (85%) of the US group and these numbers decreased
significantly after treatment to 5 (25%) and 6 (30%) subjects,
respectively. There was non-significant difference (P = 0.727) between the groups at the end of treatment (Table 3).
The same was true for the Phalen’s test, as positive results were
observed in 13 (65%) and 14 (70%) in both PEMF and US groups,
respectively, and were reduced significantly to 4 (20%) and 6 (30%),
respectively. There was a non-significant difference (P = 0.471) between the groups at the end of treatment (Table 3).
Hand grip strength showed significant improvement in both groups at the end of the intervention periods (Table 2), and PEMF showed a significantly higher level of improvement (P = 0.017,
CI 0.32–2.68) in comparison with the US group’s hand grip strength. The
functional status scores showed significant improvement intragroup (P = 0.0001) in both groups but there was non-significant difference (P = 0.414) between groups (Table 3).
Electrophysiological outcomes
Both MSDL and MMDL were
significantly decreased, and MSCV and MMCV were significantly improved,
in both groups at the end of the treatment (P < 0.05) (Table 2).
PEMF showed significant intergroup differences in both MSDL (P = 0.001,
CI ?2.23?(?1.42)) and MSCV (P = 0.0001, CI 15.3–20.03), with mean
differences of 1.83 and 17.63 respectively, in comparison with the US
group. In addition, both MMDL (P = 0.007, CI ?1.10?(?0.25)) and MMCV
(P = 0.0001, CI 3.8–7.9) showed significant differences in favour of the
PEMF group with mean differences of 0.67 and 5.86, respectively.
Discussion
CTS is a painful, debilitating
condition; it has many therapeutic options, but no single treatment
modality has been definitively established as superior to any other [21].
The results from conservative treatments vary, and there is no
widespread agreement on the best method of treatment. Likewise, the
results of surgery, with either an open or endoscopic transverse carpal
ligament release, are inconsistent [22].
Forty postnatal women who developed CTS during their third
trimester were involved in this study and were divided randomly into
one of two treatment protocols: PEMF or therapeutic US. The data showed
greater alleviation of disease symptoms with PEMF in comparison with
therapeutic US in all outcome measures except for the functional status
scale, which showed no significant difference between the two groups.
In the current study, five cases from the initial
antenatal sample had their CTS symptoms diminish in the first two weeks
after delivery. They all had significant postnatal weight loss (P = 0.0001), so their CTS regression was likely strongly related to their weight loss [23].
However, the rest of the women participants still had CTS postnatally,
which is consistent with the fact that a significant percentage of women
still have CTS symptoms up to three or more years after delivery, and
continue to wear splints [10].
Additionally, CTS is associated with hand-intensive
activities such as housework and typing, which may contribute to the
higher incidence in women [24].
This is consistent with the current study, in which the participants
were either housewives or administrative workers, in addition to being
caregivers of their new-born child.
The Phalen’s and Tinel’s tests are clinical tests for CTS; both have high sensitivity and specificity [15].
In the current study, even though not all the enrolled patients had
positive results in both these clinical tests, they were still given
treatment in both groups. This was because, while not all pregnant women
exhibit CTS symptoms, most, if not all, exhibit impaired median nerve
function [25].
In fact, these clinical signs were found to be positive in a higher
percentage of pregnant women to confirm CTS diagnosis, compared to
neurophysiological indicators [26].
Both groups performed nerve and tendon gliding exercises
as they are commonly employed for treating symptoms of CTS and are
believed to improve axonal transport and nerve conduction [27]. The benefits of these exercises are prevention of adhesion formation even if the wrist is immobilized [28],
reduction of pressure in the carpal tunnel, and maximization of the
relative excursion of the median nerve and the flexor tendons [29]. These benefits were consistent with what was observed in the current study.
The superior intergroup improvements that were recorded in
the PEMF group are attributable to the effects of PEMF on pain
perception in the form of neuron firing, calcium ion movement, endorphin
levels, acupuncture action, and nerve regeneration [30], [31].
A gating response with simultaneous stimulation of the A? fibres
produces an inhibitory anti-nociceptive effect on C fibres, which is
compatible with the Melzack–Wall hypothesis [31].
The PEMF group showed increased median nerve distal
latency and nerve conduction velocity (NCV) that can be attributed to
the stimulation of endothelial release of fibroblast growth factor
beta–2 (FGF–2) [32], which stimulates neurotrophic factors and improves the micro-environment of the tissues, leading to regeneration of the nerve [33]. In the available literature, there is limited research on PEMF treatment for CTS [13]; nevertheless, a few studies support the current findings. In such studies, pilot data of static [34] and dynamic PEMF [35], [36]
directed to the carpal tunnel region revealed significantly reduced
neuropathic pain. Another research trial applied combined static and
dynamic magnetic fields for 4 h per day over two months. There was
significant pain reduction, but only mild improvement in objective
neuronal functions in the magnetic treatment group versus placebo [37].
This mode of treatment was not appropriate in the current study because
of the need to avoid long-term exposure of the newborn to PEMF at home.
Despite there being no prior recorded side effects with treatment by
magnetic therapy [38],
patients were instructed not to bring their babies during sessions.
They were also instructed to report side effects at any time, such as
dizziness, headache, metallic taste in the mouth, or seizures.
Fortunately, no patient in the PEMF group reported any of these side
effects.
In contrast to the previously mentioned studies that found
significant improvement with PEMF treatment, two small randomized
trials [39], [40]
concluded that there were no differences between the PEMF treatment and
placebo groups. Both groups experienced insignificant improvement in
symptoms. These results may be due to the treatment short duration (two
weeks of PEMF application) in these studies.
Despite the intergroup superior effect of PEMF, the US
group also exhibited significant intragroup improvements. These
improvements are attributable to the ultrasonic thermal effects, leading
to an increase in blood flow, local metabolism and tissue regeneration,
and reduced inflammation, oedema and pain, thereby facilitating the
recovery of nerve compression [41].
There is an inverse relationship between fibre size and sensitivity to
US; hence, C fibres are more sensitive than A fibres. This selective
absorption by smaller fibres may lead to a decrease in pain transmission
[42]. Furthermore, the current study used deep, pulsed US (1 MHz and intensity of 1.0 W/cm2)
over the carpal tunnel for 15 min, since superficial, continuous US was
found to be no more effective than placebo US, and did not improve
median nerve conduction [43], [44].
In addition, deep pulsed US has been
shown to decrease pain and paresthesia symptoms, reduce sensory loss,
and improve median NCV and strength when compared with placebo US [43], [45]. This form of US treatment can also provide a positive effect on sensation and patient-reported symptoms [43].
In the current study, this was captured by the functional status scale,
which showed no significant difference between the two groups.
Conclusions
It can be concluded that PEMF has a
significant and superior effect on CTS in postnatal women, as compared
to therapeutic US. This superior effect was found in the reduction in
pain, improvement in the electrophysiological studies, and hand grip
strength. There are no reported side effects, discomforts, or known
health risks from PEMF therapy, and it is generally accepted that brief
exposure to this modality is safe [38], [46]. PEMF has lower treatment costs than surgery [47],
but its cost effectiveness in comparison with other therapeutic options
needs further investigation. There is a need to develop a treatment
guideline for CTS, which includes a combination of different modalities
and techniques.
Limitations
The current study had some
limitations that should be addressed in future research, such as the
small sample size. The literature lacks information about the standard
PEMF dose for CTS, so a comparison of different PEMF doses is also
needed. In addition, the current study did not investigate the long-term
effect of the interventions.
Conflict of interest
The authors have declared no conflict of interest.
Footnotes
Peer review under responsibility of Cairo University.
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.
Adv Med Sci. Oct 29:1-5. [Epub ahead of print]
Comparison of the long – term effectiveness of physiotherapy
programs with low – level laser therapy and pulsed magnetic field in
patients with carpal tunnel syndrome.
Dakowicz A, Kuryliszyn-Moskal A, Koszty?a-Hojna B, Moskal D, Latosiewicz R.
Source
Department of Rehabilitation, Medical University of Bialystok, Bialystok, Poland.
Abstract
Purpose: The aim of the study was to compare the long term effects of
low – level laser therapy (LLLT) and pulsed magnetic field (PMF) in the
rehabilitation of patients with carpal tunnel syndrome (CTS).Methods:
The study included 38 patients with idiopathic CTS, confirmed by
electroneurographic (ENG) examination. All patients were randomly
assigned to 2 groups: group L (18 patients) treated with LLLT a
nd group M (20 patients) with PMF therapy. Clinical assessment,
including day and night pain, the presence of paresthesia, functional
tests (Phalen, Tinel, armband tests) and pain severity according to the
Visual Analogue Scale (VAS) was conducted before treatment, after the
first series of 10 sessions, after a two-week break, after the second
series of 10 sessions and six months after the last series.
Results: After LLLT a significant reduction of day and night pain was
observed at each stage of treatment and 6 months after the last series
(p<0.05). However, in group M, a significant reduction of both day
and night pain was demonstrated only after the second series
(p<0.05). A reduction of the incidence of Phalen’s symptoms were
noticed in both groups, however, only in group L the improvement was
significant (p<0.05). In groups L and M a significant reduction of
pain intensity was observed at every stage of treatment (p<0.05).
Conclusions: Although after LLL as well as PMF therapy clinical
improvement was observed, the most significant differences were
registered after the second series and persisted for up to 6 months in
both groups.
Arch Phys Med Rehabil. 2010 Jul;91(7):981-1004.
Carpal tunnel syndrome. Part I: effectiveness of nonsurgical treatments–a systematic review.
Huisstede BM, Hoogvliet P, Randsdorp MS, Glerum S, van Middelkoop M, Koes BW.
Department of General Practice, Erasmus Medical Center, Rotterdam, The Netherlands. b.huisstede@erasmusmc.nl
Abstract
OBJECTIVE: To review literature systematically concerning
effectiveness of nonsurgical interventions for treating carpal tunnel
syndrome (CTS).
DATA SOURCES: The Cochrane Library, PubMed, EMBASE, CINAHL, and PEDro
were searched for relevant systematic reviews and randomized controlled
trials (RCTs).
STUDY SELECTION: Two reviewers independently applied the inclusion criteria to select potential studies.
DATA EXTRACTION: Two reviewers independently extracted the data and assessed the methodologic quality.
DATA SYNTHESIS: A best-evidence synthesis was performed to summarize
the results of the included studies. Two reviews and 20 RCTs were
included. Strong and moderate evidence was found for the effectiveness
of oral steroids, steroid injections, ultrasound, electromagnetic field
therapy, nocturnal splinting, and the use of ergonomic keyboards
compared with a standard keyboard, and traditional cupping versus heat
pads in the short term. Also, moderate evidence was found for ultrasound
in the midterm. With the exception of oral and steroid injections, no
long-term results were reported for any of these treatments. No evidence
was found for the effectiveness of oral steroids in long term.
Moreover, although higher doses of steroid injections seem to be more
effective in the midterm, the benefits of steroids injections were not
maintained in the long term. For all other nonsurgical interventions
studied, only limited or no evidence was found.
CONCLUSIONS: The reviewed evidence supports that a number of
nonsurgical interventions benefit CTS in the short term, but there is
sparse evidence on the midterm and long-term effectiveness of these
interventions. Therefore, future studies should concentrate not only on
short-term but also on midterm and long-term results.
Pain Med. 2008 Jul-Aug;9(5):493-504.
A randomized controlled trial of the effects of a combination of static and dynamic magnetic fields on carpal tunnel syndrome.
Weintraub MI, Cole SP.
Department of Neurology, New York Medical College, Valhalla, New York, USA. miwneuro@pol.net
Abstract
OBJECTIVE: To determine if a physics-based combination of
simultaneous static and time-varying dynamic magnetic field stimulation
to the wrist 4 hours/day for 2 months can reduce subjective neuropathic
pain and influence objective electrophysiologic parameters of patients
with carpal tunnel syndrome (CTS).
METHODS: Randomized, double-blinded, placebo-controlled trial of 36
symptomatic hands. Primary endpoints were visual analog scale (VAS) and
neuropathic pain scale (NPS) scores at baseline and 2 months and a
Patient’s Global Impression of Change (PGIC) questionnaire at the end of
2 months. Secondary endpoints were neurologic examination, median nerve
distal latencies (compound muscle action potential [CMAP]/sensory nerve
action potential [SNAP]), dynamometry, pinch gauge readings, and
current perception threshold (CPT) scores. An “active” device was
provided gratis at the end of the study, with 15 subjects voluntarily
remaining within the open protocol an additional 2-10 months and using
the preselected primary and secondary parameters.
RESULTS: (two months). Of the 31 hands, 25 (13 magnet, 12 sham) had
moderate to severe pain (VAS > 4). The VAS and PGIC revealed a
nonsignificant pain reduction. NPS analyses (anova) demonstrated a
statistically significant reduction of “deep” pain (35% downward arrow
vs 12% upward arrow, P = 0.018), NPS Total Composite (decreases of 42%
vs 24%, P = 0.042), NPS Total Descriptor Score (NPS 8; 43% vs 24%), and
NPS 4 (42% vs 11%). Motor strength, CMAP/SNAP, and CPT scores were not
significantly changed. Of the 15 hands with up to 10 months of active
PEMF (pulsed electromagnetic fields) exposure, there was objective
improvement in nerve conduction (CMAP = 53%, SNAP = 40%, >1 SD), and
subjective improvement on examination (40%), pain scores (50%), and PGIC
(70%). No detectable changes in motor strength and CPT.
CONCLUSIONS: PEMF exposure in refractory CTS provides statistically
significant short- and longterm pain reduction and mild improvement in
objective neuronal functions. Neuromodulation appears to influence
nociceptive-C and large A-fiber functions, probably through ion/ligand
binding.
Noninvasive magnetic stimulation has
been widely used in autonomic disorders in the past few decades, but
few studies has been done in cardiac diseases. Recently, studies showed
that low-frequency electromagnetic field (LF-EMF) might suppress atrial
fibrillation by mediating the cardiac autonomic nervous system. In the
present study, the effect of LF-EMF stimulation of left stellate
ganglion (LSG) on LSG neural activity and ventricular arrhythmia has
been studied in an acute myocardium infarction canine model. It is shown
that LF-EMF stimulation leads to a reduction both in the neural
activity of LSG and in the incidence of ventricular arrhythmia. The
obtained results suggested that inhibition of the LSG neural activity
might be the causal of the reduction of ventricular arrhythmia since
previous studies have shown that LSG hyperactivity may facilitate the
incidence of ventricular arrhythmia. LF-EMF stimulation might be a novel
noninvasive substitute for the existing implant device-based electrical
stimulation or sympathectomy in the treatment of cardiac disorders.
Previous studies have demonstrated that
the activation and remodeling of left stellate ganglion (LSG) induced by
myocardial infarction1,2 might be the immediate triggering mechanisms of ventricular arrhythmia (VA) and sudden cardiac death3,4, and suppressing LSG neural activity might be a feasible antiarrhythmic therapy5. In the past decades, LSG denervation and blocking have been shown to be benefit for reducing VA6.
However, undesirable side effects, such as cervical injury and Horner’s
syndrome, have limited the clinic use of LSG denervation or blocking.
Therefore, exploring a novel noninvasive approach is necessary.
Transcranial magnetic stimulation (TMS), a
neurostimulation and neuromodulation technique based on the principle of
electromagnetic induction of an electric field in the brain, has been
proposed for treatment of a variety of neurological disorders. Previous
studies has shown that TMS might mediate the cardiac rhythm by
modulating the autonomic nervous system7. Scherlag et al.8 showed
that exposure the vagal trunks or the chest to the low-frequency
magnetic field (LF-EMF) might suppress atrial fibrillation, whereas
exposure to the high-frequency field might induce atrial fibrillation by
autonomic modulating. Recently, Yu et al.9 further
demonstrated that LF-EMF stimulation of the vagal trunks or chest might
suppress atrial fibrillation by inhibiting the neural activity of
atrial ganglionated plexus. In this study, we hypothesized that exposure
LSG to the LF-EMF might inhibit the LSG neural activity, thereby
reducing VAs after acute myocardial infarction6.
Results
LSG was exposed to intermittent LF-EMF stimulation before left anterior descending artery occlusion in LF-EMF group (Fig. 1A–C).
Both the blood pressure and heart rate were kept at a stable level
during the LF-EMF stimulation. No visible damage was shown in LSG or
cardiac tissue after 90?min LF-EMF treatment. All dogs developed ECG
ST-segment and/or T-wave changes acutely after ligating the left
anterior descending artery.
Schematic representation of the position of the LF-EMF (A), stimulus pattern (B) and the experimental design flow chart (C).
LSG, left stellate ganglion; LF-EMF, low-frequency electromagnetic
field; LAD, left anterior descending artery; MAP, monophasic action
potential; HRV, heart rate variability; VA, ventricular arrhythmia.
Effect of LF-EMF stimulation on myocardial infarction-induced VAs
Figure 2A shows
the representative examples of VAs in the Control group and LF-EMF
group. As compared to the Control group, both the number of ventricular
premature beat (VPB) and the number of non-sustained ventricular
tachycardia (VT) were significantly decreased (Fig. 2B,C). Furthermore, the incidence of sustained VT/VF was significantly suppressed (75.0% vs 12.5%, P?<?0.05, Fig. 2D) in the LF-EMF group.
Representative examples (A) and the incidence (B–E)
of AMI-induced VAs in the Control group (n?=?8) and EMF group (n?=?8).
*P?<?0.05 and **P?<?0.05 as compared to the Control group. AMI,
acute myocardial infarction; VPB, ventricular premature beats; VT,
ventricular tachycardia; VF, ventricular fibrillation; other
abbreviations as in Fig. 1.
Effect of LF-EMF stimulation on MAP
Figure 3A–F demonstrates the effect of LF-EMF on action potential duration at 90% repolarization (APD90, Fig. 3A–C), pacing cycle length of action potential duration alternans (PCL, Fig. 3D–F) and the maximal slope of the restitute curve (Smax, Fig. 3G–I). As compared to group baseline, no significant change was shown in APD90, PCL or Smax obtained from different sites of left ventricle in the Control group, whereas a significant change was shown in APD90, PCL and Smax of those sites both at 30?min and 90?min after LF-EMF stimulation in the LF-EMF group (Fig. 3A–F).
Effect of LF-EMF stimulation on APD90 (A,B), PCL (C,D) and Smax (E,F) in the Control group (n?=?8) and EMF group (n?=?8). *P?<?0.05 and **P?<?0.05 as compared to the group baseline; #P?<?0.05 and ##P?<?0.05
as compared to the Control group. LVA, left ventricular apex; LVM, the
median of left ventricle; LVB, left ventricular base; MAP, monophasic
action potential; APD, action potential duration; APD90,
monophasic action potential duration determined at 90% of
repolarization; PCL, pacing cycle length of APD alternans; BH, baseline;
Smax, the maximal slope of the restitution curve, other abbreviations
are identical to Fig. 1.
Effect of LF-EMF stimulation on heart rate variability
Figure 4 demonstrates
that both low frequency component (LF) and the ratio between LF the
high component (LF/HF) were significantly decreased by LF-EMF
stimulation both at 30?min and 90?min later but not by sham LF-EMF
stimulation as compared to group baseline. In comparison with group
baseline, acute myocardial infarction resulted in a significant change
in LF (2.54?±?0.23?ms2 vs 1.72?±?0.12?ms2, P?<?0.01, Fig. 4A), high frequency component (HF, 1.01?±?0.08?ms2 vs 1.43?±?0.18?ms2, P?<?0.01, Fig. 4B) and LF/HF (2.51?±?0.34 vs 1.20?±?0.20, P?<?0.01, Fig. 4C) in the Control group, whereas those were kept at a normal level in the LF-EMF group (LF, 1.52?±?0.1?1?ms2 vs 1.68?±?0.10?ms2; HF, 1.43?±?0.12?ms2 vs 1.48?±?0.13?ms2; LF/HF, 1.06?±?0.10 vs 1.14?±?0.19, all P?>?0.05, Fig. 4A–C).
Effect of LF-EMF stimulation on LF (A), HF (B) and LF/HF (C) in the Control group (n?=?8) and EMF group (n?=?8). *P?<?0.05 and **P?<?0.01 vs group baseline; #P?<?0.05 and ##P?<?0.05
as compared to the Control group. LF, low frequency; HF, high
frequency; LF/HF, the ratio between LF and HF; BH, baseline. Other
abbreviations are identical to those in Fig. 1.
Effect of LF-EMF stimulation on serum norepinephrine and LSG function
In comparison with group baseline,
serum norepinephrine was decreased from 180.3?±?6.8?pg/ml to
162.5?±?5.8?pg/ml at 30?min later and to 160.3?±?5.2?pg/ml at 90?min
later in the LF-EMF group, whereas kept a stable level in the Control
group (Fig. 5A).
Furthermore, the systolic blood pressure increase in response to LSG
stimulation was kept a baseline level in the Control group (Fig. 5B), whereas significantly attenuated by LF-EMF in the LF-EMF group at a voltage of 20–30?V as compared to group baseline (Fig. 5C).
Take 25?V for example, the maximal systolic blood pressure increase
induced by LSG stimulation was decreased from 88.3?±?15.4% to
43.1?±?6.2% (P?<?0.01) at 90?min later, whereas kept at about 90% in
the Control group (Fig. 5B,C).
Effect of LF-EMF stimulation on serum NE (A) and LSG function (B,C)
in the Control group (n?=?8) and EMF group (n?=?8). NS, P?>?0.05,
*P?<?0.05 and **P?<?0.01 as compared to the Control group at the
same time point. NE, norepinephrine. Other abbreviations are alike to
those in Fig. 1.
Effect of LF-EMF stimulation on the neural activity of LSG
Figure 6A shows
the representative examples of LSG neural activity at baseline, 30?min
after LF-EMF stimulation, 90?min after LF-EMF stimulation and 15?min
after acute myocardial infarction. Figure 6B,Cdemonstrates
that no significant difference was shown both in the frequency and the
amplitude of LSG neural activity between the Control group and the
LF-EMF group. As compared to group baseline, LF-EMF stimulation resulted
in a significant decrease in LSG neural activity at 30?min and 90?min
later, whereas no significant change was caused by sham LF-EMF
stimulation (Fig. 6B,C).
Furthermore, as compared to baseline, the neural activity was
significantly increased after acute myocardial infarction in the Control
group (Frequency: 62.5?±?5.2impulse/min vs 112.2?±?8.1impulse/min,
P?<?0.01; Amplitude: 0.18?±?0.03?mV vs 0.33?±?0.05?mV, P?<?0.01)
but kept at a comparable level in the LF-EMF group (Frequency:
60.8?±?4.8impulse/min vs 65.6?±?4.8impulse/min, P?>?0.05; Amplitude:
0.19?±?0.02?mV vs 0.18?±?0.02?mV, P?>?0.05).
Representative examples (A) and quantitative analysis (B,C) of LSG neural activity in the Control group (n?=?8) and EMF group (n?=?8). **P?<?0.01 as compared to group baseline; #P?<?0.05 and ##P?<?0.05 as compared to the Control group. All abbreviations are identical to Figs 1 and ?and22.
Discussion
In the present study, we applied LF-EMF at the body surface of LSG. Both the ventricular electrophysiological parameters (APD90,
PCL, Smax) and autonomic neural activity (serum norepinephrine, LSG
function and LSG neural activity) were significantly affected by LF-EMF
stimulation. Furthermore, the acute myocardial infarction-induced
increased neural activity of LSG was significantly attenuated and the
VAs was significantly reduced by LF-EMF. These findings suggested that
exposure the LSG to LF-EMF might significantly reduce the neural
activity of LSG, therefore reducing the incidence of VAs.
Previous studies have shown that activation of LSG facilitates, whereas inhibition of LSG protects against VAs4,10. In the past two decades, TMS has been widely used in clinical neurology11,12.
Amounts of studies have shown that high-frequency stimulation increases
cortical excitability, whereas low-frequency stimulation decreases
neuronal excitability11,12. Recently, studies also demonstrated that TMS might affect the cardiac rhythm by modulating the autonomic nervous system7. Scherlag et al.8 showed
that high-frequency magnetic stimulation of the vagal nerves might
induce atrial tachycardia and atrial fibrillation, which was eliminated
after propranolol and atropine injection. Low-frequency stimulation of
the vagal nerves, however, reduced the heart rate and decreased the
voltage required to induce atrioventricular conduction block8.
Furthermore, recent study demonstrated that exposure the heart to the
LF-EMF might significantly suppress atrial fibrillation and the
mechanism might be by modulating the neural activity of atrial
ganglionated plexus9.
In the present study, we found that exposure the LSG to the LF-EMF
significantly reduced the serum norepinephrine, neural activity of LSG
and VAs. All these indicate that noninvasive LF-EMF might reduce VAs by
facilitating the autonomic rebalance, but what underlie the beneficial
effects of LF-EMF on LSG was poorly defined.
In the present study, we suggested some possible
mechanisms underlying the suppressing of LSG neural activity. Firstly,
TMS, as an effective treatment for patients with neural disorders, has
been implicated long-lasting therapeutic effects after the cessation of
TMS treatment13.
Most researchers have contributed these effects to be long-term
depression (LTD) and long-term potentiation (LTP) cause the duration of
the effects seemed to implicate changes in synaptic plasticity13.
LTD is caused by low-frequency stimulation or the stimulation of a
postsynaptic neuron, whereas LTP is caused by high-frequency stimulation
or the stimulation of a presynaptic neuron13.
Ca++ signal, which is known to regulate membrane excitability and
modulate second messengers related to multiple receptors and signal
transduction pathways, has been shown to be the major determinant
whether LTD or LTD arises14,15. Recently, Scherlag et al.8 also
suggested that LTP or LTD was existed cause exposure the chest to the
low-frequency electromagnetic field for 35?mins might result in the
suppression of atrial fibrillation for 3 to 4?hours after the
application of LF-EMF. In the present study, we also found that
pretreatment with LF-EMF might significantly attenuated the acute
myocardial infarction-induced activation of LSG neural activity and VAs,
suggesting that LTP or LTD might be a potential explain for the
salutary effects of LF-EMF stimulation. Secondly, previous studies have
shown that TMS might also affect the expression levels of various
receptors and other neuromediators, such as ?-adrenoreceptors, dopamine11,16,17.
In the present study, serum norepinephrine was significantly decreased
after exposure to the LF-EMF, indicating that modulating the
neurotransmitters might be one of the underlying mechanisms underlying
the salutary effects of LF-EMF stimulation. Thirdly, previous studies
also showed that TMS might also modulate dentritic sprouting (axon
growth) and the density of synaptic contacts, and the authors suggested
that these results are associated with the Brain-derived neurotrophic
factor (BDNF)-tyrosine kinase B (TrkB) signaling system18,19.
BDNF, as the most abundant neurotrophin in the brain, was reported to
be a major contributor to the N-methyl-D-aspartate receptor-dependent
LTP and LTD processes20. Wang et al.21 demonstrated
that low-frequency TMS might reduce BDNF levels. High-frequency
stimulation, however, might increase serum BDNF levels and the affinity
of BDNF for TrkB receptors. Furthermore, previous studies also showed
that trancranial stimulation might result in the changes in
neural-related proteins, such as c-fos and tyrosine hydroxylase, which
are closely related with the neural remodeling processes6,13,20. Autonomic neural remodeling, however, plays a key role in the initiation and maintenance of VAs4,10.
All these implicate that modulating autonomic neural remodeling might
be another mechanism of the antiarrhythmic effect of LF-EMF stimulation.
Fourthly, the above mainly shows the underlying mechanisms of LF-EMF
stimulation, but how can the LSG perceive the LF-EMF remains unknown.
During the past few decades, many mechanisms, which might provide the
basis for how the animals detect magnetic fields, have been proposed22.
However, the magnetoreceptors have not been identified with certainty
in any animal, and the mode of transduction for the magnetic sense
remains unknown23. Recently, Xie et al.
hypothesized that the putative magnetoreceptor, the iron-sulphur
cluster protein, might combine with the magnetoreception-related
photoreceptor cryptochromes to form the basis of magnetoreception in
animals and this was corroborated in pigeon retina24. Furthermore, Zhang et al.
further showed that the cells which had been transfected iron-sulphur
cluster protein might response to the remote magnetic stimulation25.
All these indicate that the iron-sulphur cluster protein might be the
potential magnetoreceptor for the animals to detect the magnetic fields.
Though the present study showed wonderful results, but
there are some limitations in this study. First, anesthesia with
pentobarbital might affect the autonomic nervous system. However, this
could be counteracted cause anesthesia was maintained continuously
during the whole surgery and conducted in a same fashion in both groups.
Second, the coil used in this study is too large to achieve
LSG-targeted stimulation without affecting the surrounding tissues. It
would be a great step forward if the coils could be technically
improved. Third, we only observed the effect of LF-EMF in acute canine
model. Fourth, we mainly focused on the autonomic nervous system
imbalance, one of the major contributors of post-infarction VAs, cause
we intervened the LSG with LF-EMF in this study. It’s a great limitation
that some other major factors, like area at risk, infarct size, degree
of collateral flow and the possibility of any preconditioning pathway
were not involved in this study. However, previous studies have shown
that LSG activation might facilitate the incidence of VAs, whereas
pre-emptive or post-ischemic/infarction LSG inhibition by blockage or
denervation might decrease the incidence of VAs and improve the infarct
size, collateral flow, contractile force both in animals26,27,28,29 and patients30,31.
Furthermore, studies have shown that LSG stimulation might increase the
likelihood of early or delayed afterdepolarization development and the
initiation of reentry, thereby resulting in the incidence of VAs32,33,34.
In this study, LF-EMF stimulation of the LSG might significantly
inhibit the neural activity of LSG, thereby reducing the incidence of
VAs. Therefore, it’s reasonable to refer that improving the above
factors might also be the potential mechanisms underlying the beneficial
effects of LF-EMF stimulation, but further studies with optimized
parameters and all-round considerations are required in the future.
In conclusion, the present study showed
that LF-EMF stimulation might significantly reduce the neural function
and neural activity of LSG. Exposure the LSG to the LF-EMF might be a
feasible method for preventing the acute myocardial infarction-induced
VAs. However, larger studies with optimized parameters should be done in
the chronic models to verify the beneficial effect of LF-EMF
stimulation.
Methods
Animal preparation
Sixteen canines weighing between 20
and 25?kg were included in this study. The experiments were approved by
the Animal Ethics Committee of Wuhan University under approval number
2015–0445 and followed the guidelines outlined by the Care and Use of
Laboratory Animals of the National Institutes of Health. All surgeries
were performed under anesthesia with sodium pentobarbital at an initial
dose of 30?mg/kg and a maintenance dose of 60?mg/h. The depth of
anesthesia was evaluated by monitoring corneal reflexes, jaw tone, and
alterations in cardiovascular indices. The body surface
electrocardiogram was recorded throughout the experiment with a
computer-based Lab System (Lead 2000B, Jingjiang Inc., Wuhan, China).
The core body temperature of the dogs was kept at 36.5?±?1.5?°C. Left
thoracotomy was conducted at the fourth intercostal space. At the end of
the experiment, canines were a lethal dose of pentobarbital (100?mg/kg,
iv).
LF-EMF
Repeated LF-EMF was supplied by the
magnetic stimulation machine (YRD CCY-I, YiRuiDe Inc., Wuhan, China)
with the curve 8 coil located at the body surface of the LSG (Fig. 1A).
The LSG was stimulated by intermittent (8?s ON, 10?s OFF) LF-EMF
stimulation with the frequency set at 1?HZ and intensity at
approximately 90% of motor threshold (Fig. 1B).
Motor threshold was defined as the lowest electromagnetic intensity
that induced muscle contractions in the proximal forepaw and shoulder.
Monophasic action potential recording
Monophasic action potentials from
the left ventricle were recorded with a custom-made Ag–AgCl catheter. A
dynamic steady state pacing protocol (S1S1) was performed to determine
action potential duration alternans35.
The pulse train was delivered at an initial cycle length slightly
shorter than the sinus cycle length and the drive train of stimuli was
maintained for 30?s to ensure a steady state, and then a 2-min
interruption was taken to minimize the pacing memory effects. After
that, another pulse train with the PCL decreased by 10?ms was delivered
until action potential duration alternans appeared. Action potential
duration alternans was defined as ?APD90?10?ms for ?5 consecutive beats36.
The monophasic action potential recordings were analyzed by the LEAD
2000B work station system (Lead 2000B, Jingjiang Inc. China). The APD90 was defined as the 90% repolarization duration and the diastolic interval was the time interval from the previous APD90 point
to the activation time of the following beat. As described in previous
studies, the dynamic action potential duration restitution curves were
constructed from (Diastolic interval, APD90) pairs using Origin 8.0 (OriginLab, Co., Northampton, MA, USA)35,37. Slope of the shortest diastolic interval was defined as Smax.
Measurements of heart rate variability
Spectral power for heart rate
variability was analyzed on 5-minute electrocardiogram recording
segments and an autoregressive algorithm was used to analyze digitized
signals from the electrocardiographic recordings. The following power
spectral variables were determined: HF, LF and LF/HF38.
Neural recording from the LSG
To record the neural activity of
the LSG, one tungsten-coated microelectrode was inserted into the fascia
of the LSG and one ground lead was connected to the chest wall. The
signal of the LSG was recorded with a PowerLab data acquisition system
(8/35, AD Instruments, Australia) and amplified by an amplifier (DP-304,
Warner Instruments, Hamden, CT, USA). The band-pass filters were set at
300?Hz to 1?kHz and the amplification ranges from 30 to 50 times39.
The neural activity, deflections with a signal-to-noise ratio greater
than 3:1, was manually determined as described in our previous studies39,40,41.
LSG function
LSG function was measured as the
LSG stimulation-induced maximal change in systolic blood pressure as
described in our previous study38.
High frequency stimulation (20?Hz, 0.1?ms pulse duration) was applied
to the LSG using a stimulator (Grass-S88; Astro-Med, West Warwick, RI,
USA). The voltage ranged from 20?V to 30?V and increased by 5?V. To
eliminate the residual effect of the LSG stimulation, each stimulation
should be less than 30?s and the next stimulation should be not be taken
until the blood pressure returned to a normal level.
Blood sampling
Venous blood samples were
collected. Serum was separated by centrifuging at 3000?rpm for 15?min at
4?°C, and stored at ?80?°C until assayed. The serum norepinephrine
level was measured with a canine-specific high sensitivity ELISA kit
(Nanjing Jiancheng Bioengineering Institute, Nanjing City, China)38.
Measurement of the acute myocardial infarction-induced VAs
The left anterior descending
coronary artery was ligated at approximately 2.5?centimeters away from
its origin to induce acute myocardial infarction. The incidence and
duration of the VAs induced by acute myocardial infarction during the
first hour was analyzed. The VAs recorded on the ECG were defined as
following42:
VPBs, identifiable premature QRS complexes; VT, three or more
consecutive VPBs; non-sustained VT, VT terminating spontaneously within
30?s; sustained VT, VT sustained for more than 30?s; and VF, a
tachycardia with random ECG morphology and an associated loss of
arterial blood pressure that degenerates into ventricular asystole.
Experimental protocol
Sixteen dogs were randomly divided
into LF-EMF group (n?=?8, with LF-EMF) and Control group (n?=?8, with
sham LF-EMF). LF-EMF (1?HZ; stimulation time 8?s; interstimulus
interval, 5?s) was delivered to the surface area of LSG for 90?minutes.
As shown in Fig. 1C,
monophasic action potential, heart rate variability, serum
norepinephrine, LSG function and LSG neural activity were measured at
baseline, 30?min and 90?min after LF-EMF treatment. Measurements of
heart rate variability and LSG neural activity were repeated at 15?min
after acute myocardial infarction. Furthermore, the incidence of VAs was
recorded during the first hour after acute myocardial infarction.
Statistical analysis
Continuous variables are presented
as the mean?±?SEM and were analyzed by t test, one-way ANOVA, or two-way
repeated-measures ANOVA with a Bonferroni posthoc test. To compare the
incidence of VF between groups, Fisher’s exact test was used. All data
was analyzed by GraphPad Prism version 5.0 software (GraphPad Software,
Inc., San Diego, CA), and two-tailed P???0.05 was considered
significant.
Additional Information
How to cite this article: Wang, S. et al.
Noninvasive low-frequency electromagnetic stimulation of the left
stellate ganglion reduces myocardial infarction-induced ventricular
arrhythmia. Sci. Rep.6, 30783; doi: 10.1038/srep30783 (2016).
Acknowledgments
This work was supported by the grants from National
Natural Science Foundation of China No. 81270339, No. 81300182, No.
81530011, No. 81570463, grant from the Natural Science Foundation of
Hubei Province No. 2013CFB302, and grants from the Fundamental Research
Funds for the Central Universities No. 2042014kf0110 and No.
2042015kf0187.
Footnotes
Author Contributions S.W.
and X.Z. wrote the main manuscript text and prepared figures; B.H.,
Z.W., L.Z. and M.W. performed experiments and anlalyzed data; L.Y. and
H.J. designed the project and revised the paper. All authors reviewed
and approved the final version.
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Articles from Scientific Reports are provided here courtesy of Nature Publishing Group
Biosci Rep. 2016 Dec; 36(6): e00420.
Published online 2016 Dec 5. Prepublished online 2016 Oct 25. doi: 10.1042/BSR20160082
PMCID: PMC5137536
Novel protective effects of pulsed electromagnetic field ischemia/reperfusion injury rats
Extracorporeal
pulsed electromagnetic field (PEMF) has shown the ability to regenerate
tissue by promoting cell proliferation. In the present study, we
investigated for the first time whether PEMF treatment could improve the
myocardial ischaemia/reperfusion (I/R) injury and uncovered its
underlying mechanisms.
In our
study, we demonstrated for the first time that extracorporeal PEMF has a
novel effect on myocardial I/R injury. The number and function of
circulating endothelial progenitor cells (EPCs) were increased in PEMF
treating rats. The in vivo results showed that per-treatment of
PEMF could significantly improve the cardiac function in I/R injury
group. In addition, PEMF treatment also reduced the apoptosis of
myocardial cells by up-regulating the expression of anti-apoptosis
protein B-cell lymphoma 2 (Bcl-2) and down-regulating the expression of
pro-apoptosis protein (Bax). In vitro, the results showed that
PEMF treatment could significantly reduce the apoptosis and reactive
oxygen species (ROS) levels in primary neonatal rat cardiac ventricular
myocytes (NRCMs) induced by hypoxia/reoxygenation (H/R). In particular,
PEMF increased the phosphorylation of protein kinase B (Akt) and
endothelial nitric oxide synthase (eNOS), which might be closely related
to attenuated cell apoptosis by increasing the releasing of nitric
oxide (NO). Therefore, our data indicated that PEMF could be a potential
candidate for I/R injury.Keywords: apoptosis, Bax, B-cell lymphoma 2 (Bcl-2), ischaemia/reperfusion (I/R) injury, pulsed electromagnetic field (PEMF)
INTRODUCTION
Hypertension,
arrhythmia, myocardial infarction (MI) and myocardial
ischaemia/reperfusion (I/R) injury are all the most common cardiac
diseases, which are the major causes of mortality in the world [1].
Among them, myocardial I/R injury is the most important cause of
cardiac damage. Its pathological process is closely related to
postoperative complications [2,3]
caused by coronary artery vascular formation, coronary
revascularization and heart transplantation. After myocardium suffered
severe ischaemia, restoration of the blood flow is a prerequisite for
myocardial salvage [2]. However, reperfusion may induce oxidative stress [4], inflammatory cell infiltration and calcium dysregulation [5]. All these players contribute to the heart damage such as contraction and arrhythmias [6], generally named myocardial I/R injury. Recently, more and more evolving therapies have been put into use for I/R injury.
Pulsed electromagnetic field
(PEMF) is the most widely tested and investigated technique in the
various forms of electromagnetic stimulations for wound healing [7], alleviating traumatic pain and neuronal regeneration [8,9].
The rats were randomly divided into PEMF-treated (5 mT, 25 Hz, 1 h
daily) and control groups. They hypothesized the possible mechanism that
PEMF would increase the myofibroblast population, contributing to wound
closure during diabetic wound healing. It is a non-invasive and
non-pharmacological intervention therapy. Recent studies indicated that
PEMF also stimulated angiogenesis in patients with diabetes [10], and could improve arrhythmia, hypertension and MI [1]. The MI rats were exposed to active PEMF for 4 cycles per day (8 min/cycle, 30±3 Hz, 6 mT) after MI induction. In vitro,
PEMF induced the degree of human umbilical venous endothelial cells
tubulization and increased soluble pro-angiogenic factor secretion [VEGF
and nitric oxide (NO)] [7].
However, the role of PEMF in ischaemia and reperfusion diseases remains
largely unknown. Our study aimed to investigate the effects of PEMF
preconditioning on myocardial I/R injury and to investigate the involved
mechanisms.
In our
study, we verified the cardioprotective effects of PEMF in myocardial
I/R rats and the anti-apoptotic effects of PEMF in neonatal rat cardiac
ventricular myocytes (NRCMs) subjected to hypoxia/reoxygenation (H/R).
We hypothesized that PEMF treatment could alleviate myocardial I/R
injury through elevating the protein expression of B-cell lymphoma 2
(Bcl-2), phosphorylation of protein kinase B (Akt). Meanwhile, it could
decrease Bax. We emphatically made an effort to investigate the MI/R
model and tried to uncover the underlying mechanisms.
MATERIALS AND METHODS
Animals
Male,
12-week-old Sprague Dawley (SD) rats (250–300 g) were purchased from
Shanghai SLAC Laboratory Animal. Animals were housed in an
environmentally controlled breeding room and given free access to food
and water supplies. All animals were handled according to the “Guide for
the Care and Use of Laboratory Animals” published by the US National
Institutes of Health (NIH). Experimental procedures were managed
according to the Institutional Aminal Care and Use Committee (IACUC),
School of Pharmacy, Fudan University.
The measurement of blood pressure in SHR rats
At
the end of 1 week treatment with PEMF, the rats were anesthetized with
chloral hydrate (350 mg/kg, i.p.), the right common carotid artery (CCA)
was cannulated with polyethylene tubing for recording of the left
ventricle pressures (MFlab 200, AMP 20130830, Image analysis system of
physiology and pathology of Fudan University, Shanghai, China).
Myocardial I/R injury rat model and measurement of infarct size
All
the rats were divided into three groups: (1) Sham: The silk was put
under the left anterior descending (LAD) without ligation; (2) I/R:
Hearts were subjected to ischaemia for 45 min and then reperfusion for
4 h; (3) I/R + PEMF: PEMF device was provided by Biomobie Regenerative
Medicine Technology. The I/R rats were pre-exposed to active PEMF for 2
cycles per day (8 min per cycle), whereas other two groups were housed
with inactive PEMF generator. I/R was performed by temporary ligation of
the LAD coronary artery for 45 min through an incision in the fourth
intercostal space under anaesthesia [11].
Then, the ligature was removed after 45 min of ischaemia, and the
myocardium was reperfused for 4 h. Ischaemia and reperfusion were
confirmed and monitored by electrocardiogram (ECG) observation. The
suture was then tightened again, and rats were intravenously injected
with 2% Evans Blue (Sigma–Aldrich). After explantation of the hearts,
the left ventricles were isolated, divided into 1 mm slices, and
subsequently incubated in 2% 2,3,5-triphenyltetrazolium chloride (TTC;
Sigma–Aldrich) in 0.9% saline at 37°C for 25 min, to distinguish
infarcted tissue from viable myocardium. These slices were flushed with
saline and then fixed in 10% paraformaldehyde in PBS (pH 7.4) for 2 h.
Next, the slices were placed on a glass slice and photographed by
digital camera, the ImageJ software (NIH) was used in a blind fashion
for analysis. Infarct size was expressed as a ratio of the infarct area
and the area at risk [12].
Pulsed electromagnetic field treatment
PEMF
were generated by a commercially available healing device (length ×
width × height: 7 cm × 5cm × 3cm) purchased from Biomoble Regenerative
Medicine Technology. The adapter input voltage parameter is
approximately 100–240 V and output parameter is 5 V. Fields were
asymmetric and consisted of 4.5 ms pulses at 30±3 Hz, with an adjustable
magnetic field strength range (X-axis 0.22±0.05 mT, Y-axis 0.20±0.05 mT, Z-axis
0.06±0.02 mT). The I/R rats were housed in custom designed cages and
exposed to active PEMF for 2 cycles per time (8 min for 1 cycle),
whereas the I/R rats were housed in identical cages with inactive PEMF
generator. For in vitro study, culture dishes were directly exposed to PEMF for 1–2 cycles as indicated (8 min for 1 cycle, 30 Hz, X-axis 0.22 mT, Y-axis 0.20 mT, Z-axis 0.06 mT) [1]. The background magnetic field in the room area of exposure animals/samples and controls is 0 mT.
Detection of myocardium apoptosis
Terminal
deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL)
assay was applied to analyse cardiomyocyte apoptosis. Heart samples were
first fixed in 10% formalin and then paraffin embedded at day 14. Then,
the hearts were cut into 5 ?m sections. TUNEL staining was carried out
as described previously [12]. When apoptosis occurred, cells would look green.
Determination of myocardial enzymes in plasma
Blood samples were collected after haemodynamic measurement and centrifuged at 3000 g for
15 min to get the plasma. Creatine kinase (CK), lactate dehydrogenase
(LDH), creatine kinase isoenzyme-MB (CKMB) and ?-hydroxybutyrate
dehydrogenase (HBDH) were quantified by automatic biochemical analyzer
(Cobas 6000, Roche). All procedures were performed according to the
manufacturer’s protocols.
Myocardium cells morphology via TEM
At
the end of the experiment, sections from myocardial samples of left
ventricular were immediately fixed overnight in glutaraldehyde solution
at 4°C and then incubated while protected from light in 1% osmium
tetroxide for 2 h. After washing with distilled water for three times
(5 min each), specimens were incubated in 2% uranyl acetate for 2 h at
room temperature and then dehydrated in graded ethanol concentrations.
Finally, sections were embedded in molds with fresh resin. The changes
in morphology and ultrastructure of the myocardial tissues were observed
and photographed under a TEM [13].
Scal-1+/flk-1+ cells counting of endothelial progenitor cells
We
applied antibodies to the stem cell antigen-1 (Sca-1) and fetal liver
kinase-1 (flk-1) to sign endothelial progenitor cells (EPCs) as
described before, and used the isotype specific conjugated anti-IgG as a
negative control. The amount of Scal-1+/flk-1+ cells would be counted by flow cytometry technique [14].
Measurement of nitric oxide concentration and Western blotting
Plasma
concentrations of NO were measured with Griess assay kit (Beyotime
Institute of Biotechnology) according to the manufacturer’s protocol.
The expressions of Bax, Bcl-2, p-Akt, Akt, p-endothelial nitric oxide
synthase (eNOS), eNOS and glyceraldehyde-3-phosphate dehydrogenase
(GAPDH) were assessed using Western blot as described recently [15].
Proteins were measured with Pierce BCA Protein Assay Kit (Thermo).
Hippocampal protein lysates (50 mg/well) were separated using (SDS/PAGE)
under reducing conditions. Following electrophoresis, the separated
proteins were transferred to a PVDF membrane (Millipore). Subsequently,
non-specific proteins were blocked using blocking buffer (5% skim milk
or 5% BSA in T-TBS containing 0.05% Tween 20), followed by overnight
incubation with primary rabbit anti-rat antibodies specific for target
proteins as mentioned before (Cell Signaling Technology) at 4°C. Blots
were rinsed three times (5 min each) with T-TBS and incubated with
horseradish peroxidase (HRP)-conjugated secondary antibody (1:10000,
Proteintech) for 2 h at room temperature. The blots were visualized by
using enhanced chemiluminescence (ECL) method (Thermo). GAPDH was
applied to be the internal control protein. Intensity of the tested
protein bands was quantified by densitometry.
Cell culture
Primary neonatal rat cardiac ventricular myocytes (NRCMs) were collected as previously described [15].
Briefly, the ventricles of new born SD rats (1–3 days old) were minced
and digested with 0.125% trypsin. Isolated cardiomyocytes were cultured
in Dulbecco’s modified Eagle’s medium/F-12 (DMEM/F12, Life Technologies)
supplemented with 10% (v/v) FBS (Life Technologies), 100 units/ml
penicillin and 100 mg/ml streptomycin. The following experiments used
spontaneously beating cardiomyocytes 48–72 hours after plating. (37°C
with 5% CO2).
Cell treatment (hypoxia/reoxygenation)
NRCMs were prepared according to the methods recently described [15].
To establish the H/R model, the cells were cultured in DMEM/F-12
without glucose and serum. The cells were exposed to hypoxia (99% N2+5% CO2)
for 8 h, followed by reoxygenation for 16 h. The cells were pretreated
with PEMF for 30 min before the H/R procedure. The control group was
cultured in DMEM/F-12 with low glucose (1000 mg/l) and 2% serum under
normoxic air conditions for the corresponding times.
Cell viability assays
The
viability of NRCMs cultured in 96-well plates was measured by using the
Cell Counting Kit-8 (CCK-8) (Dojindo Molecular Technologies) according
to the manufacturer’s instructions. The absorbance of CCK-8 was obtained
with a microplate reader at 450 nm.
Measurement of intracellular reactive oxygen species levels
Reactive
oxygen species (ROS) levels in NRVMs were determined by dihydroethidium
(DHE, Sigma–Aldrich) fluorescence using confocal microscopy (Zeiss, LSM
710). After different treatments, cells were washed with D-PBS and
incubated with DHE (10 ?mol/l) at 37°C for 30 min in the dark. Then,
residual DHE was removed by PBS-washing. Fluorescent signals were
observed (excitation, 488 nm; emission, 610 nm) under a laser confocal
microscope (Zeiss).
Data analysis
All
the data were presented as means ± S.E.M. Differences were compared by
one-way ANOVA analysis by using SPSS software version 19.0 (SPSS) and P value <0.05 was taken as statistically significant.
RESULTS
PEMF could lower blood pressure under treatment of certain PEMF intensity in SHR rat model (double-blind)
To
determine whether PEMF has any effects on blood pressure of SHR rats, we
treated SHR rats with different PEMF intensity 1–4 cycles per day for
7 days and measured the blood pressure changes via CCA. We observed that
PEMF treatment could significantly lower the blood pressure in the
Bioboosti WIN235 and WI215-stimulating groups than that in non-treated
ones (Figures 1A and ?and1B).1B).
But Bioboosti WIN221 and WC65 treating groups did not have any effects
on the blood pressure in SHR rats, compared with the non-treated ones (Figures 1C and ?and1D).1D). Fields were asymmetric and consisted of 4.5 ms pulses at 30±3 Hz, with an adjustable magnetic field strength range (X-axis 0.22±0.05 mT, Y-axis 0.20±0.05 mT, Z-axis
0.06±0.02 mT). The I/R rats were housed in custom designed cages and
exposed to active PEMF for 2 cycles per time (8 min for 1 cycle),
whereas the I/R rats were housed in identical cages with inactive PEMF
generator.
Figure 1The effect of PEMF on SHR rats in vivo. PEMF
could lower the blood pressure in SHR rats. At day 7 treatment with
different intensity PEMF, blood pressure was recorded via CCA [1(A),
1(B), 1(C) and 1(D)]. Data were represented as the mean ±…
According to this result, we chose Bioboosti WIN235 as our needed PEMF to carry out the following experiments.
PEMF treatment could observably improve the abundance of EPCs
Amplifying
EPCs abundance and function is an active focus of research on
EPCs-mediated neovascularization after I/R. Thus, the number of
circulating EPCs was identified by Sca-1/flk-1 dual positive cells as
described. We determined that PEMF treatment could remarkably increase
the number of Scal-1+/flk-1+ cells in peripheral blood at postoperative days 7 and 14 (Figure 2).
Figure 2The effect of PEMF on the number of Scal-1+/flk-1+ cells after treating EPSc for 7 and 14 days. PEMF treatment notably increased the number of Scal-1+/flk-1+ cells after treating EPSc for 7 and 14 days. Data were represented as the mean…
Preliminary assessment of PEMF showed great protective effect against myocardial infarction/reperfusion injury (MI/RI) rat model
To
examine the effect of PEMF on myocardial I/R, male SD rats were divided
into three groups: Sham, I/R and I/R+ PEMF (2 cycles per day, 8 min per
cycle) per day until 28 days. We observed that PEMF stimulation could
significantly decrease four plasma myocardial enzymes (LDH, CK, CKMB and
HBDH) in I/R rats (Figure 3A).
Additionally, we found that pre-stimulating PEMF could improve the
cardiac morphology via TEM, compared with I/R+ PEMF group. TEM revealed
the rupture of muscular fibres, together with mitochondrial swelling,
and intracellular oedema in Group I/R. The shape of nucleus was
irregular, with evidence of mitochondrial overflow after cell death.
Compared with Group I/R+ PEMF, less muscular fibres were ruptured, with
mild swelling of mitochondria, mild intercellular oedema and less cell
death. In Group Sham, the ruptured muscular fibres, mitochondrial or
intracellular oedema and dead cells were not observed (Figure 3B).
To further confirm protective effect of PEMF, we measured the MI size
by applying TTC and Evans Blue staining in all three groups. The MI area
in I/R+ PEMF group could be reduced, compared with the model rats in
I/R group (Figure 3C).
Figure 3Protective effect of PEMF on I/R rats in vivo. Plasma myocardial enzymes (LDH, CK, HBDH and CKMB) content was quantified by automatic biochemical analyzer (A) (n=18 in each group). Changes on cardiac cell morphology via TEM (B) (n=6 in…
In vivo, PEMF dramatically reduced cell apoptosis induced by I/R injury
As H/R of
cardiomyocytes contributed to cell death, we also detected the effect
on myocardial apoptosis by using TUNEL kit, as shown in Figure 4(A).
We uncovered that PEMF pretreating could dramatically decrease
apoptosis of myocardial cells in I/R + PEMF group, compared with I/R
group. In addition, we also found that PEMF treatment could
significantly increase the expression of anti-apoptosis protein Bcl-2,
p-eNOS and p-Akt and down-regulated the expression of pro-apoptosis
protein Bax in the heart tissue, as shown in Figure 4(B).
Figure 4Apoptotic cardiomyocyte was
identified by TUNEL analysis, apoptotic cardiomyocyte appears green
whereas TUNEL-negative appears blue (A), photomicrographs were taken at
×200 magnification. Apoptosis-related protein Bcl-2, Bax, p-Akt level of
different…
The effect of PEMF on cell viability in neonatal rat cardiac ventricular myocytes
To further investigate whether PEMF has the same effect in vitro, we simulated the I/R injury model in vitro.
We applied NRCMs and hypoxia incubator to mimic myocardial I/R injury
via H/R as described in the section ‘Materials and Methods’. We found
that PEMF treatment (2 cycles) could remarkably improve cell viability,
compared with the H/R group (Figure 5). For in vitro study, culture dishes were directly exposed to PEMF for 1–2 cycles as indicated (8 min for 1 cycle, 30±3 Hz, X-axis 0.22±0.05 mT, Y-axis 0.20±0.05 mT, Z-axis 0.06±0.02 mT).
Figure 5NRCMs viability measured by
CCK-8 assay at the end of the treatment for 72 h. PEMF treatment
enhanced the cell viability of hypoxia NRCMs. Data were represented as
the mean ± S.E.M.
Specific-density PEMF could decrease intracellular ROS levels of primary cardiomyocytes subjected to hypoxia/reperfusion
As shown in Figure 6(A),
NRCMs that were subjected to H/R increased significantly the ROS level,
whereas the ROS level had been decreased in PEMF group (2 cycles), in
contrast with the H/R group. Representative images of the ROS level were
displayed in Figure 6(B). At the same time, we identified the effect on NRCMs apoptosis after suffering H/R by using TUNEL kit. As shown in Figure 6(C),
cell apoptosis in the H/R group was aggravated, whereas PEMF treatment
could reduce the cell death. Representative images of TUNEL staining
were shown in Figure 6(D).
Figure 6PEMF protected Neonatal rat
cardiac ventricular myocytes (NRCMs) from hypoxia/reoxygenation
(H/R)-induced apoptosis via decreasing ROS levelat the end of the
treatment for 72 h in vitro.
Effect of PEMF on NO releasing via Akt/eNOS pathway
Cultured
NRCMs were treated with PEMF stimulation for 1 to 2 cycles and the
supernatant and cell lysate were collected. When cells suffered H/R,
intracellular levels of p-Akt, p-eNOS and Bcl-2 were decreased, whereas
PEMF treatment could increase the phosphorylation of Akt, p-eNOS and
Bcl-2 (Figures 7A–7C). The expression of Bax was increased when cells subjected to H/R whereas PEMF treatment reversed such increase (Figure 7C). Western blot analysis was shown in Figure 7(D) for p-Akt/Akt, Figure 7(E) for p-eNOS/eNOS, Figure 7(F) for Bcl-2 and Figure 7(G) for Bax.
Figure 7The related protein
expression about the effect of PEMF on apoptosis induced by
hypoxia/reoxygenationat the end of the treatment for 72 h in vitro. PEMF increased the phosphorylation of Akt, endothelial nitric oxide synthase (eNOS), and the expression…Go to:
DISCUSSION
Our
present study provides the first evidence that PEMF has novel functions
as follows: (1) We treated SHR rats with different PEMF intensity (8 min
for 1 cycle, 30±3 Hz, X-axis 0.22±0.05 mT, Y-axis 0.20±0.05 mT, Z-axis
0.06±0.02 mT) 1–4 cycles per day for 7 days. PEMF can lower blood
pressure under treatment of certain PEMF intensity in SHR rat model
(double-blind). (2) PEMF has a profound effect on improving cardiac
function in I/R rat model. (3) PEMF plays a vital role in inhibiting
cardiac apoptosis via Bcl-2 up-regulation and Bax down-regulation. (4) In vitro,
PEMF treatment also has a good effect on reducing ROS levels by
Akt/eNOS pathway to release NO and improving cell apoptosis in NRCMs
subjected to hypoxia.
Many previous studies
showed that extracorporeal PEMF-treated(5 mT, 25 Hz, 1 h daily) could
enhance osteanagenesis, skin rapture healing and neuronal regeneration,
suggesting its regenerative potency [8,16,17].
And some researchers had found that PEMF therapy (8 min/cycle, 30±3 Hz,
6 mT) could improve the myocardial infarct by activating VEGF–Enos [18] system and promoting EPCs mobilized to the ischaemic myocardium [1,19].
Consistent with the previous work, our present study demonstrated that
PEMF therapy could significantly alleviate cardiac dysfunction in I/R
rat model.
Recent evidence suggest
that circulating EPCs can be mobilized endogenously in response to
tissue ischaemia or exogenously by cytokine stimulation and the
recruitment of EPCs contributes to the adult blood vessels formation [19,20,21].
We hypothesized that PEMF could recruit more EPCs to the vessels. To
confirm our hypothesis, we applied antibodies to the Sca-1 and flk-1 to
sign EPC. The results indicated that PEMF could remarkably increase the
number of EPCs in the PEMF group, compared with the I/R group.
Previous evidence indicated that when heart suffered I/R, cardiac apoptosis would be dramatically aggravated [22–24].
Myocardial apoptosis plays a significant role in the pathogenesis of
myocardial I/R injury. We assumed that PEMF might play its role in
improving cardiac function through inhibiting cell apoptosis. The Bcl-2
family is a group of important apoptosis-regulating proteins that is
expressed on the mitochondrial outer membrane, endoplasmic reticulum
membrane and nuclear membrane. Overexpression of Bcl-2 proteins blocks
the pro-apoptosis signal transduction pathway, thereby preventing
apoptosis caused by the caspase cascade [25].
The role Bax plays in autophagy is a debatable. Recently, new genetic
and biochemical evidence suggest that Bcl-2/Bcl-xL may affect apoptosis
through its inhibition of Bax [26].
Overexpression of Bax protein promotes the apoptosis signal pathway. In
the present study, we applied TUNEL staining to find that PEMF has a
perfect effect on cardiac cell apoptosis by regulating apoptosis-related
proteins Bcl-2 and Bax [25,26,27,28].
To verify our findings in the rat model, we mimicked I/R condition in vitro by hypoxia exposure in NRCMs. Results showed that not only in vivo, hypoxia could induce cell apoptosis in vitro.
And we also found that PEMF treatment could significantly alleviate
cell apoptosis induced by hypoxia. At the basal level, ROS play an
important role in mediating multiple cellular signalling cascades
including cell growth and stress adaptation. Conversely, excess ROS can
damage tissues by oxidizing important cellular components such as
proteins, lipids and DNA, as well as activating proteolytic enzymes such
as matrix metalloproteinases [29].
Previous studies showed that when cells were subjected to hypoxia, the
intracellular ROS level would be sharply increased, and the
overproduction of ROS would result in cell damage [19,30,31].
In the present study, PEMF treatment could prominently down-regulate
ROS levels. We also investigated how PEMF reduced the intracellular ROS
level.
NO appears to mediate distinct pathways in response to oxidative stress via AKt–eNOS pathway [32,33].
NO is identified as gaseous transmitters. In vascular tissue, NO is
synthesized from L-arginine by nitric oxide synthase (NOS) and it is
considered to be the endothelium-derived relaxing factor. Evidence show
that the NO generation in endothelium cells was damaged in hypertensive
patients [34]. NO could also prevent platelet activation and promote vascular smooth muscle cells proliferation [35]. NO generation from eNOS is considered to be endothelium-derived relaxing and ROS-related factor [36,37]. Some researchers found that bradykinin limited MI induced by I/R injury via Akt/eNOS signalling pathway in mouse heart [38].
And bradykinin inhibited oxidative stress-induced cardiomyocytes
senescence by acting through BK B2 receptor induced NO release [39].
Such evidence indicated that Akt phosphorylation could activate eNOS,
which lead to NO releasing, and resulted in ROS reducing. In the present
study, we found that PEMF decreased ROS via Akt/eNOS pathway.
In
conclusion, this is the first study suggesting that PEMF treatment could
improve cardiac dysfunction through inhibiting cell apoptosis.
Furthermore, in vitro, we first clarified PEMF still plays a
profound effect on improving cell death and removing excess ROS via
regulating apoptosis-related proteins and Akt/eNOS pathway. All these
findings highlight that PEMF would be applied as a potentially powerful
therapy for I/R injury cure.
Acknowledgments
We thank all of the members of the Laboratory of Pharmacology of Chen Y., Ding Y.J. for their technical assistance.
Fenfen Ma designed and performed experiments on MI/RI rat model, histological stain and Western blot. Wenwen Li assisted the in vivo experiments, validated the effect in vitro experiments,
analysed data and wrote the manuscript. Xinghui Li interpreted data and
formatted manuscript. Rinkiko Suguro, Ruijuan Guan, Cuilan Hou, Huijuan
Wang and Aijie Zhang interpreted data and edited manuscript. Yichun Zhu
and YiZhun Zhu proposed the idea and supervised the project.
FUNDING
This
work was supported by the key laboratory program of the Education
Commission of Shanghai Municipality [grant number ZDSYS14005].
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Am J Transl Res. 2014; 6(3): 281–290.
Published online May 15, 2014
Coronary artery disease is a leading cause of morbidity and mortality
in modern society. Massive loss of cardiac muscle after several
ischemic episodes lead to compromised cardiac function, remodeling and
low quality life of patients. A growing body of evidence in experimental
models of cardiac injury suggests that early re-establishment of blood
perfusion to the injured myocardium would restrict infarct expansion,
prevent cardiac remodeling and maintain cardiac function [1–3].
Although several strategies for therapeutic angiogenesis including the
delivery of growth factors, gene therapy and stem cell implantation have
been investigated, unsolvable theoretical limitations are still
remaining [4–8]. For instance, the limited survival of implanted stem cell, uncontrolled angiogenesis and others [9–11]. Therefore, a safe, effective and non-invasive treatment for myocardial ischemia may be an ideal approach.
The therapeutic efficacy of
various forms of electromagnetic stimulations, including capacitative
coupling, direct current, combined magnetic fields, and pulsed
electromagnetic field (PEMF), have been intensely investigated [12]. Among them, extracorporeal PEMF is the most widely tested techniques in the topic of osteanagenesis [13], skin rapture healing [14] and neuronal regeneration [15,16].
Recently, several study also indicated that PEMF exhibited the
capability to stimulate angiogenesis and endothelial proliferation [17–19], however the detailed mechanism remains modest understood.
In the
present study, we investigated whether extracorporeal PEMF therapy was
able to rescue ischemic myocardium through inhibiting cardiac apoptosis
as well as promoting postnatal neovascularization in a rat model of
myocardial infarction (MI).
Material and methods
Animals
Male
Sprague-Dawley (SD) rats weighing 250-300 g were provided by
Sino-British SIPPR/BK Laboratory Animal (Shanghai, China). Animals were
housed with controlled temperature (22-25°C) and lighting (08:00-20:00
light, 20:00-08:00 dark), and free access to tap water and standard rat
chow. All the animals in this work received humane care in compliance
with institutional guidelines for health and care of experimental
animals of Shanghai Jiao Tong University.
MI model
All
rats (n=36) were subjected to permanent left anterior descending artery
ligation to establish MI model. Briefly, left thoracotomy and
pericardiectomy were performed, and the hearts were gently exteriorized.
Left anterior descending artery was ligated 4 mm below the left atrium
with a 5-0 silk suture. The chest wall was then closed and the animals
were returned to home cages. MI rats were then randomly divided into
PEMF treated and untreated groups.
PEMF treatment
PEMF
were generated by a commercially available healing device purchased from
Biomobie Regenerative Medicine Technology (Shanghai, China). Fields
were asymmetric and consisted of 4.5 ms pulses at 30 ± 3 Hz, with a
magnetic flux density increasing from 0 to 5 mT in 400 ?s. The MI rats
were housed in custom-designed cages and exposed to active PEMF for 4
cycles per day (8 minutes for 1 cycle), while the control rats were
housed in identical cages with inactive PEMF generator. For in vitro study, culture dishes were directly exposed to PEMF for 1-4 cycles as indicated (8 minutes for 1 cycle, 30 ± 3 Hz, 5 mT).
Echocardiography
Trans-thoracic
echocardiographic analysis was performed using an animal specific
instrument (VisualSonics, Vevo770; VisualSonicsInc, Toronto, Canada), at
postoperative day 7, 14 and 28. Rats were anesthetized with 10% chloral
hydrate solution. After shaving the chest, pre-warmed ultrasound
transmission gel was applied to the chest and two dimensional-directed
M-mode and Doppler echocardiographic studies were carried out. The
ejection fraction (EF) and fractional shortening (FS) were used to
assess left ventricular systolic function. All measurements were
averaged for consecutive cardiac cycles and triplicated.
Capillary density
Capillary
density in peri-infarcted zone (PIZ) was determined by anti-CD31
staining (R&D Systems, San Diego, CA, USA). Briefly, 14 days after
MI, rats were euthanized and hearts were perfused with a 0.9% NaCl
solution followed by 4% solution of paraformaldehyde in 0.1 mol/L
phosphate buffer (pH 7.4), and then dissected and fixed in this solution
for 24 h. Next, samples were washed, dehydrated in a graded ethanol
series and embedded in paraffin. 5 ?m-sections were cut transversely at
200 ?m intervals from into 5 slices from the ligation site to the apex.
Endothelial capillaries were identified by goat anti-rat antibody of
CD31 (5 ?g/ml, Becton-Dickinson Biosciences, Franklin Lakes, NJ, USA),
and followed by a secondary antibody (Invitrogen, Carlsbad, CA, USA).
Capillary density was determined by counting of 10 randomly selected
fields and is expressed as numbers of capillary/field (×400
magnification) [20,21].
Enzyme-linked immunosorbent assay (ELISA)
The
concentration of vascular endothelial growth factor (VEGF) and nitric
oxide (NO) contained in conditional media of cultured HUVECs was
measured using ELISA kit purchased from R&D Systems (San Diego, CA,
USA). The concentrations of VEGF contained in PIZ was determined by
ELISA kits purchased from Raybiotech (Norcross, GA, USA) [22].
Western blotting
PIZ
tissue and HUVECs were homogenized with ice-cold homogenizing buffer (20
?l/gram tissue, 50 mmol/l Tris-HCl, 150 mmol/l NaCl, 1 mmol/l EDTA, and
0.5 mmol/l Triton X-100, pH 7.4) and protease inhibitor cocktail (5 mM,
Roche, Berlin, Germany). Proteins were measured with Pierce BCA Protein
Assay Kit (Thermo, Asheville, North Carolina, USA). Hippocampal protein
lysates (50 mg/well) were separated using SDS-PAGE under reducing
conditions. Following electrophoresis, the separated proteins were
transferred to a polyvinylidene difluoride membrane (Millipore,
Billerica, Massachusetts, USA). Subsequently, nonspecific proteins were
blocked using blocking buffer (5% nonfat dried milk in T-TBS containing
0.05% Tween 20), followed by incubation with primary rabbit anti-rat
antibodies specific for phospho-Akt (p-Akt), total Akt,
hypoxic-inducible factor (HIF)-1? (Santa Cruz, California, USA),
phospho-endothelial nitric oxide synthase (p-eNOS), total eNOS and
?-actin (Cell Signaling Technology, Beverly, MA, USA) overnight at 4°C.
Blots were washed four times with 0.1% Tween 20 in PBS and incubated
with HRP-conjugated secondary antibody (1/5000; Biochain, Newark,
California, USA) for 1 h at room temperature. The bands were visualized
using enhanced chemiluminescence method (Bioimaging System; Syngene,
Cambridge, UK). Intensity of the tested protein bands was quantified by
densitometry.
Detection of apoptosis
Heart
samples were fixed in 10% formalin and then paraffin embedded at day
14. Then, the hearts were cut into 5-?m sections. Terminal
deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)
staining was carried out using a commercially available kit according to
the manufacturer’s instructions (Promega, Madison, Wisconsin, USA).
Nuclei were stained by DAPI (Roche) [23].
Three mid-ventricular sections of each heart (from the apex to the
base) were analyzed. Ten fields in the PIZ were randomly selected from
each section for the calculation of the percentage of apoptotic nuclei
(apoptotic nuclei/total nuclei) and the obtained ratios were averaged
for statistical analysis.
Isolation of circulating endothelial progenitor cells (EPCs)
Circulating
EPCs were obtained by cardiac puncture after animals were anesthetized.
Peripheral blood-derived mononuclear cells (PB-MNCs) were then purified
by Histopaque-1083 (Sigma-Aldrich, St. Louis, MO, USA) density gradient
centrifugation at 400 g for 30 min. The mononuclear layer was then
collected and re-suspended in endothelial growth medium-2 (EGM-2,
Clonetics, San Diego, CA, USA). Antibodies to the stem cell antigen-1
(Sca-1) and Flk-1 were used to mark EPC as described before), and the
isotype specific conjugated anti-IgG was used as a negative control.
Sca-1+ and Flk-1+ cells were gated in the mononuclear cell fraction.
EPC migration assay
Migratory
activity of PB-EPCs from PEMF-treated and untreated rats was evaluated
by a 24-well modified Boyden chamber assay (Transwell, Corning, NY, USA)
[24]. After cultured with EGM-2 for 4 days, PB-EPCs were trypsinized and 5×105
cells in 100 ?l of EBM-2 with 0.1% BSA in placed in the upper
compartments. 50 ng/mL recombinant vascular endothelial growth factor
(VEGF, Clonetics) in 600 ?L of chemotaxis buffer (serum-free EBM-2, 0.1%
BSA) was added to the lower compartment. The chamber was incubated at
37°C for 6 hrs. The cells were then fixed and stained with hematoxylin
and eosin (H&E). Non-migrated cells on the filter’s upper surface
were removed using a cotton swab. The numbers of migrated cells were
counted in 4 random high-power fields (HPF, ×400 magnification) and
averaged for each sample.
Tube formation assay
Matrigel-Matrix
(BD Biosciences, Franklin Lakes, New Jersey, USA) was inserted in the
well of a 48-well cell culture plate and a number of 5×104 EPCs or HUVECs were seeded [25].
After
incubation in EGM-2, images of tube morphology was taken and tube number
was counted at random under four low power fields (magnifications ×40)
per sample. Capillary tube branch points were counted in six randomly
selected fields per well, and used as an index for tube formation.
Cell culture
Human
umbilical vein endothelial cells (HUVECs, passage 3) were purchased
from Clonetics (San Diego, CA, USA) and EGM-2 in a humidified atmosphere
of 5% CO2
and 95% air. HUVECs were reseeded into plates coated with Matrix gel
and stimulated for 1-4 cycles of PEMF stimulation (5.5 mT, 8 minutes per
cycle). Supernatant and cell lysates were collected at 24 hrs after
reseeding. Additionally, HUVECs-formed vasculature was quantified by
calculating its length under microscopic photography 24 hrs after
reseeding [26].
Statistical analysis
Data
are expressed as means ± standard deviation (SD). Student’s t-test was
used for statistical analyses. SPSS software version 17.0 (SPSS Inc.,
Chicago, IL, USA) was used. A value of p<0.05 was considered significant.Go to:
Results
PEMF promotes cardiac function after MI
To
determine whether PEMF could increase myocardial function in MI rats,
echocardiographic studies were carried out at postoperative day 7, 14
and 28. We observed that PEMF had no effects on body weight and heart
rates when compared with control group (Table 1). Meanwhile, higher EF and FS values were detected in PEMF-treated rats than control (Figure 1), indicating that PEMF preserves left ventricular contractility after MI damage.
Figure 1
Echocardiography after PEMF therapy. All rats were subjected to MI
and randomly separated to control and PEMF group. The data of (A)
ejection fractions and (B) fractional shorting in both groups collected
in day 7, 14 and 28. Values are mean ±…
Table 1
Effect of PEMF on cardiac functions of MI rats
PEMF enhances angiogenesis in PIZ
To examine
whether the changes in the cardiac function are associated with changes
in capillary EC formation, we measured capillary densities of PEMF and
control rats in PIZ through anti-CD31 immunofluorescence staining at
postoperative day 14. Representative photomicrographs are shown in Figure 2A. Quantitative analyses by counting the CD31+ capillary ECs revealed that PEMF treatment significantly increases capillary densities in PIZ than control rats (Figure 2B). PEMF treatment also increased the protein levels of VEGF and HIF-1? in damaged hearts (Figure 2C and ?and2D),2D), as well as enhancing the phosphorylation of Akt signal pathway in ischemic myocardium at postoperative day 14 (Figure 2E).
Figure 2
Pro-angiogenic effect of PEMF in ischemic myocardium. A:
Immunofluorescence staining of CD31-positive cells in the infarct border
zone at postoperative day 14 in PEMF-treated and control rats. B:
Quantitative analyses of capillary density between 2 groups…
Protective effect of PEMF to MI-induced cardiac apoptosis
We
evaluated the effect of PEMF on the survival of myocardium in response
to hypoxia in vivo at postoperative day 7. The number of TUNEL positive
nucleus in PIZ significantly increased in PEMF-treated rats compared
with the non-treated ones (Figure 3), indicating that PEMF treatment decreases the susceptibility of cardiomyocytes to hypoxic damage.
Figure 3
Anti-apoptotic benefit of PEMF in damaged myocardium. A: TUNEL
staining for cardiac cell apoptosis (green) and DAPI (blue) for nuclear
staining in the border zone 14 days after AMI (×400 magnification). B:
Quantitative analysis of the TUNEL-positive…
PEMF augments EPC-mediated neovascularization
EPC-mediated neovascularization after myocardial infarction supported their therapeutic potential [27].
Thus, the strategy to amplify EPC abundance and function is an active
focus of research. The number of circulating EPCs was identified by stem
cell antigen-1 (Sca-1)/fetal liver kinase-1 (flk-1) dual positive cells
as described. We found that PEMF treatment increased the number of
Sca-1+/flk-1+ cells in peripheral blood at postoperative day 7 and 14 (Figure 4A).
Additionally, EPCs isolated from PEMF-treated rats exhibited enhanced
tube formative capacity and migratory ability when compared with control
ones in vitro (Figure 4B and ?and4C),4C), which suggesting that PEMF increases the abundance and regenerative capacity of EPCs.
Figure 4
PEMF enhanced circulating endothelial progenitor cells (EPCs)
function in MI Rats. 7 and 14 days after AMI induction, peripheral blood
was collected from rats in both groups. A: Quantitative analysis of
Sca-1/flk-1 dual positive PB-EPCs isolated from…
Pro-angiogenic beneficial of PEMF in vitro
Cultured
HUVECs were treated with PEMF stimulation for 1 to 4 cycles and the
supernatant and cell lysate were collected. PEMF promoted VEGF and NO
releasing from cultured HUVECs in a dose-dependent manner (Figure 5A and ?and5B).5B). Additionally, the phosphorylation of eNOS in HUVECs was also enhanced in response to PEMF following a dose dependent manner (Figure 5C). Finally, the HUVEC-formed tubes were lengthened by PEMF in a dose dependent manner (Figure 6).
Figure 5
Enhancement of the expression of VEGF and nitric oxide in
PEMF-treated HUVECs. PEMF stimulated vascular endothelial growth factors
secretion concentration dependently. Bar graph of the concentrations of
(A) VEGF and (B) nitric oxide released from HUVECs…
Figure 6
Effects of PEMF on tube formation of cultured HUVECs.
Representative images of tube formation in HUVECs by stimulated PEMF for
1-4 cycles and quantitative analysis of tube length formed by
PEMF-treated HUVECs. Values are mean ± SEM; n=4. *means…Go to:
Discussion
Major
findings of our study are: (1) PEMF prevents cardiomyocytes against
hypoxia-induced apoptosis and preserves cardiac systolic function in a
rat MI model; (2) PEMF induces angiogenesis and vasculogenesis through
activating VEGF-eNOS system and promoting EPCs mobilized to the ischemic
myocardium.
We demonstrated that PEMF
treatment preserved the cardiac systolic function after MI and prevented
cardiac apoptosis. Previous report demonstrated that PEMF treatment
activated voltage-gated calcium channels (VGCC) [28], which is crucial for maintaining cardiac contractility and cell survival [29,30]. Increased intracellular Ca2+produced
by PEMF-mediated VGCC activation may lead to increase of NO through the
action of eNOS, which is dominant modulator to prevent cardiomyocytes
from apoptosis and enhance revascularization in PIZ after MI [31].
Consistent with the previous work, we demonstrated that the HIF-1?/Akt
axis was activated in PIZ in PEMF rats. In addition, PEMF induced eNOS
phosphorylation in vitro, which is a key molecular served in the survival pathway in both myocardium and endothelial cell lineage [32].
Another possible mechanism
in cardiac protecting effect of PEMF is to stimulate neovascularization.
Increasing evidence suggests that neovascularization limits infarct
expansion and extension, improves cardiac remodeling [1,2]. Recent data demonstrated that PEMF stimulation induced angiogenesis and amplified endothelial cells function [17,20].
Some researchers believe that PEMF induces cellular proliferation, as
evidenced by cAMP activation and uptake of tritiated thymidine [33].
In present study, we demonstrated that the capillary density in PIZ was
increased after PEMF treatment. Moreover, PEMF therapy triggered the
Akt/HIF-1?/VEGF cascade was activated in ischemic myocardium. In in vitro
study, we confirmed PEMF-treated HUVECs released more VEGF and NO,
which are the key factors response to endothelial proliferation and
survival, suggesting that PEMF activates both autocrine and paracrine
function of mature endothelial cells. Furthermore, Tepper and colleagues
also reported that PEMF stimulated fibroblastic growth factor-2 (FGF-2)
releasing and augment angiogenesis [14].
Recent evidence indicates
that adult blood vessels may result from not only expansion of existing
endothelial cells (angiogenesis), but also the recruitment of
endothelial progenitor cells or EPCs (vasculogenesis) [24].
We hypothesized that besides mature endothelial cells, PEMF might also
act as a stimulator of progenitor (EPC). To confirm the hypothesis, we
examined the effect of PEMF on ex vivo angiogenesis. Our data
demonstrated the number of Sca-1/flk-1 dual positive EPCs in peripheral
blood increased in response to PEMF. Using the well-established Matrigel
assay, we demonstrated that PEMF was able to dramatically enhance the
tube formative capacity of either EPCs or mature endothelial cells in vitro. PEMF also accelerated the migratory ability of EPCs. Moreover, Goto et al
reported that PEMF stimulation up-regulated the expression of
angiopoietin-2 and FGF-2 in bone marrow, suggesting PEMF could promote
the regenerative capacity of myeloid-derived cells (such as EPCs) in
damaged tissue when recruited. From all these findings, we conclude that
PEMF sufficiently re-establishes blood supply to the ischemic and
hypoxic cardiomyocytes via enhancing both angiogenesis and
vasculogenesis.
In
conclusion, our findings indicate that extracorporeal PEMF treatment
increases cardiac systolic function through inhibiting cardiac apoptosis
and stimulating neovascularization in PIZ. These findings suggest that
PEMF deserves further consideration of investigation in its regulation
on the signaling pathway and new clinical strategies for ischemic
vascular diseases.Go to:
Acknowledgements
This work was supported by
the Shanghai Science and Technology Committee (11 nm 0503600), the China
National Natural Science Foundation (11374213) and Foundation of
National Lab for Infrared Physics (200901).Go to:
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Bioelectromagnetics. 2010 May;31(4):296-301.
Effects of weak static magnetic fields on endothelial cells.
Martino CF, Perea H, Hopfner U, Ferguson VL, Wintermantel E.
Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado, USA. martino@colorado.edu
Abstract
Pulsed electromagnetic fields (PEMFs) have been used extensively in
bone fracture repairs and wound healing. It is accepted that the induced
electric field is the dose metric. The mechanisms of interaction
between weak magnetic fields and biological systems present more
ambiguity than that of PEMFs since weak electric currents induced by
PEMFs are believed to mediate the healing process, which are absent in
magnetic fields. The present study examines the response of human
umbilical vein endothelial cells to weak static magnetic fields. We
investigated proliferation, viability, and the expression of functional
parameters such as eNOS, NO, and also gene expression of VEGF under the
influence of different doses of weak magnetic fields. Applications of
weak magnetic fields in tissue engineering are also discussed. Static
magnetic fields may open new venues of research in the field of vascular
therapies by promoting endothelial cell growth and by enhancing the
healing response of the endothelium.
Eur J Appl Physiol. 2007 Nov;101(4):495-502. Epub 2007 Aug 3.
Short-term effects of pulsed electromagnetic fields after physical exercise are dependent on autonomic tone before exposure.
Grote V, Lackner H, Kelz C, Trapp M, Aichinger F, Puff H, Moser M.
Institute of Noninvasive Diagnosis, JOANNEUM RESEARCH, Weiz, Austria.
Abstract
The therapeutic application of pulsed electromagnetic fields (PEMFs)
can accelerate healing after bone fractures and also alleviate pain
according to several studies. However, no objective criteria have been
available to ensure appropriate magnetic field strength or type of
electromagnetic field. Moreover, few studies so far have investigated
the physical principles responsible for the impact of electromagnetic
fields on the human body. Existing studies have shown that PEMFs
influence cell activity, the autonomic nervous system and the blood
flow. The aim of this study is to examine the instantaneous and
short-term effects of a PEMF therapy and to measure the impact of
different electromagnetic field strengths on a range of physiological
parameters, especially the autonomic nervous systems, determined by
heart rate variability (HRV) as well as their influence on subjects’
general feeling of well-being. The study comprised experimental,
double-blind laboratory tests during which 32 healthy male adults (age:
38.4+/-6.5 years) underwent four physical stress tests at standardised
times followed by exposure to pulsed magnetic fields of varying
intensity [HPM, High Performance magnetic field; Leotec; pulsed signal;
mean intensity increase: zero (placebo), 0.005, 0.03 and 0.09 T/s].
Exposure to electromagnetic fields after standardised physical effort
significantly affected the very low frequency power spectral components
of HRV (VLF; an indicator for sympathetically controlled blood flow
rhythms). Compared to placebo treatment, exposure to 0.005 T/s resulted
in accelerated recovery after physical strain. Subjects with lower
baseline VLF power recovered more quickly than subjects with higher VLF
when exposed to higher magnetic field strengths. The application of
electromagnetic fields had no effect on subjects’ general feeling of
well-being. Once the magnetic field exposure was stopped, the described
effects quickly subsided. PEMF exposure has a short-term
dosage-dependent impact on healthy subjects. Exposure to PEMF for 20 min
resulted in more rapid recovery of heart rate variability, especially
in the very low frequency range after physical strain. The study also
showed the moderating influence of the subjects’ constitutional VLF
power on their response to PEMF treatment. These findings have since
been replicated in a clinical study and should be taken into
consideration when PEMF treatment is chosen.
Rehabilitative medical technology for the correction of microcirculatory disorders in patients with arterial hypertension.
[Article in Russian]
Kul’chitskaia DB.
Abstract
The study with the use of laser Doppler flowmetry has revealed
pathological changes in the microcirculatory system of patients with
arterial hypertension. Their treatment with a low-frequency magnetic
field showed that its effect on microcirculation depends on the regime
and site of application of magnetotherapy as well as its combination
with other physical factors. Frontal application of the magnetic field
had the most pronounced beneficial effect on dynamic characteristics of
microcirculation. Pulsed regime of magnetotherapy was more efficacious
than conventional one. Amplipulse magnetotherapy produced better results
than monotherapy.
Bioelectromagnetics. 2007 Jan;28(1):64-8.
A pilot investigation of the effect of extremely low frequency pulsed electromagnetic fields on humans’ heart rate variability.
Baldi E, Baldi C, Lithgow BJ.
Diagnostic and Neurosignal Processing Research Group, Electrical
& Computer System Engineering, Monash University, Victoria,
Australia. Emilio.Baldi@eng.monash.edu.au
Abstract
The question whether pulsed electromagnetic field (PEMF) can affect
the heart rhythm is still controversial. This study investigates the
effects on the cardiocirculatory system of ELF-PEMFs. It is a follow-up
to an investigation made of the possible therapeutic effect ELF-PEMFs,
using a commercially available magneto therapeutic unit, had on soft
tissue injury repair in humans. Modulation of heart rate (HR) or heart
rate variability (HRV) can be detected from changes in periodicity of
the R-R interval and/or from changes in the numbers of heart-beat/min
(bpm), however, R-R interval analysis gives only a quantitative insight
into HRV. A qualitative understanding of HRV can be obtained considering
the power spectral density (PSD) of the R-R intervals Fourier
transform. In this study PSD is the investigative tool used, more
specifically the low frequency (LF) PSD and high frequency (HF) PSD
ratio (LF/HF) which is an indicator of sympatho-vagal balance. To obtain
the PSD value, variations of the R-R time intervals were evaluated from
a continuously recorded ECG. The results show a HR variation in all the
subjects when they are exposed to the same ELF-PEMF. This variation can
be detected by observing the change in the sympatho-vagal equilibrium,
which is an indicator of modulation of heart activity. Variation of the
LF/HF PSD ratio mainly occurs at transition times from exposure to
nonexposure, or vice versa. Also of interest are the results obtained
during the exposure of one subject to a range of different ELF-PEMFs.
This pilot study suggests that a full investigation into the effect of
ELF-PEMFs on the cardiovascular system is justified.
Georgian Med News. 2006 Jun;(135):109-13.
Influence of treatment with variable magnetic field of low frequency
in low mountain environment on cardiohemodynamic index of patients with
arterial hypertension.
[Article in Russian]
Tarkhan-Mouravi ID, Purtseladze NA.
Abstract
Pathological changes in function and action of cardiovascular system
is the significant link in formation and progression of arterial
hypertension. 68 patients were investigated. From these patients in 32
first stage of mentioned pathology, while in 36 – the II degree was
found. It is established that treatment of arterial hypertension by
variable magnetic field of low frequency in low mountain environment
causes decrease of systolic, diastolic and heart dynamic blood pressure,
normalizes heart index and pulse rate; decreases peripheral vascular
specific resistance, increases amount of upset index accelerated of
blood flow on the region “lung-ear”, improves electrocardiological data.
Mentioned pathological displacements were more expressed at the first
stage of arterial hypertension.
Bioelectromagnetics. 2005 Apr;26(3):161-72.
Decreased plasma levels of nitric oxide metabolites, angiotensin II,
and aldosterone in spontaneously hypertensive rats exposed to 5 mT
static magnetic field.
Okano H, Masuda H, Ohkubo C.
Department of Environmental Health, National Institute of Public Health, Tokyo 108-8638, Japan. okano@niph.go.jp
Previously, we found that whole body exposure to static magnetic
fields (SMF) at 10 mT (B(max)) and 25 mT (B(max)) for 2-9 weeks
suppressed and delayed blood pressure (BP) elevation in young, stroke
resistant, spontaneously hypertensive rats (SHR). In this study, we
investigated the interrelated antipressor effects of lower field
strengths and nitric oxide (NO) metabolites (NO(x) = NO(2)(-) +
NO(3)(-)) in SHR. Seven-week-old male rats were exposed to two different
ranges of SMF intensity, 0.3-1.0 mT or 1.5-5.0 mT, for 12 weeks. Three
experimental groups of 20 animals each were examined: (1) no exposure
with intraperitoneal (ip) saline injection (sham-exposed control); (2) 1
mT SMF exposure with ip saline injection (1 mT); (3) 5 mT SMF exposure
with ip saline injection (5 mT). Arterial BP, heart rate (HR), skin
blood flow (SBF), plasma NO metabolites (NO(x)), and plasma
catecholamine levels were monitored. SMF at 5 mT, but not 1 mT,
significantly suppressed and retarded the early stage development of
hypertension for several weeks, compared with the age matched, unexposed
(sham exposed) control. Exposure to 5 mT resulted in reduced plasma
NO(x) concentrations together with lower levels of angiotensin II and
aldosterone in SHR. These results suggest that SMF may suppress and
delay BP elevation via the NO pathways and hormonal regulatory systems.
Auton Neurosci. 2003 Apr 30;105(1):53-61.
Can extremely low frequency alternating magnetic fields modulate heart rate or its variability in humans?
Kurokawa Y, Nitta H, Imai H, Kabuto M.
Environmental Health Science Region, National Institute for
Environmental Studies, 16-2 Onogawa, Ibaraki Tsukuba 305-0053, Japan.kurokawa@nies.go.jp
Abstract
This study is a reexamination of the possibility that exposure to
extremely low frequency alternating magnetic field (ELF-MF) may
influence heart rate (HR) or its variability (HRV) in humans. In a
wooden room (cube with 2.7-m sides) surrounded with wire, three series
of experiments were performed on 50 healthy volunteers, who were exposed
to MFs at frequencies ranging from 50 to 1000 Hz and with flux
densities ranging from 20 to 100 microT for periods ranging from 2 min
to 12 h. In each experiment, six indices of HR/HRV were calculated from
the RR intervals (RRIs): average RRI, standard deviation of RRIs, power
spectral components in three frequency ranges (pVLF, pLF and pHF), and
the ratio of pLF to pHF. Statistical analyses of results revealed no
significant effect of ELF-MFs in any of the experiments, and suggested
that the ELF-MF to which humans are exposed in their daily lives has no
acute influence on the activity of the cardiovascular autonomic nervous
system (ANS) that modulates the heart rate.
Klin Med (Mosk). 2003;81(1):24-7.
Clinico-functional efficacy of medicinal and photon stabilization in patients with angina pectoris.
Modification of erythrocytic membrane and the trend in
clinicofunctional indices were studied in 90 patients with angina of
effort (FC I-IV) in the course of treatment with a combination of
membranoprotective drugs (group 1), magneto-laser radiation (group 2)
and imitation of laser radiation (group 3). In patients of groups 1 and 2
the treatment resulted in stabilization of cell membrane accompanied
with a hypotensive effect and increased exercise tolerance due to more
effective cardiac performance.
Saudi Med J. 2002 May;23(5):517-20.
The effect of magneto-treated blood autotransfusion on central
hemodynamic values and cerebral circulation in patients with essential
hypertension.
Alizade IG, Karayeva NT.
Department of Cardiology, Hospital of Ministry of Internal Affairs, Baku, Azerbaijan.
OBJECTIVE: The work was carried out to study the effect of
magneto-treated blood autotransfusion on the values of central and
cerebral hemodynamics in patients with essential hypertension.
METHODS: Sixty-six patients with stage II essential hypertension aged
31-60 years who underwent magneto-treated blood autotransfusion were
evaluated and treated, at the Cardiology Department, Hospital of
Ministry of Internal Affairs of the Azerbaijan Republic, over a period
of 8 years. The diagnosis was based on clinical examination and
generally accepted criteria of essential hypertension stages proposed in
1978 by the World Health Organization.
RESULTS: Sixty-six patients with stage II essential hypertension with
stable drop in blood pressure, simultaneously showed a positive
clinical effect. Central hemodynamic changes in the process of
magneto-treated blood autotransfusion were different and depended on the
initial state of circulation. High clinical effect showed the patients
with hyperkinetic type of hemodynamics. Their blood pressure were
significantly lower than the patients with hypokinetic type of
circulation.
CONCLUSION: Rheoencephalographic study demonstrated that
magneto-treated blood autotransfusion possessed insignificant effect on
cerebral hemodynamics, mainly expressed by the reduction of arterial
blood flow tension in the patients with hypokinetic type of
hemodynamics.
Ter Arkh. 2001;73(10):70-3.
Changes in blood rheological properties in patients with hypertension.
[Article in Russian]
Shabanov VA, Terekhina EV, Kostrov VA.
AIM: To study hemorheology in patients with essential hypertension (EH), to improve EH treatment in terms of blood rheology.
MATERIAL AND METHODS: Blood rheology, microcirculation, lipid plasm
spectrum, central hemodynamics were studied in 90 patients with mild and
83 patients with moderate or severe EH as well as 30 healthy controls
before and after treatment (hypotensive drugs, essential phospholipids,
intravenous laser blood radiation, plasmapheresis).
RESULTS: Hemorrheological disorders (subnormal deformability of the
red cells and elastoviscosity of their membranes, disk-spherical
transformation and hyperaggregation of blood cells, high dynamic
viscosity) correlated with the disease severity, arterial pressure and
total peripheral vascular resistance. Long-term (1-1.5 years)
hypotensive therapy, especially with combination of beta-blockers with
diuretics, has a negative effect on blood rheology. Optimisation of EH
treatment in terms of blood rheology consists in using essential
phospholipids in stable hypertension, intravenous laser radiation in
complicated hypertension, plasmapheresis in drug-resistant hypertension.
Such an approach not only significantly improves hemorheology but also
provides good clinical and hypotensive effects in 75-80% patients.
CONCLUSION: Blood viscodynamics should be taken into consideration in individual treatment of hypertensive patients.
Med Tr Prom Ekol. 2001;(6):20-3.
Influence of low-frequency magnetotherapy and HF-puncture on the heart rhythm in hypertensive workers exposed to vibration.
[Article in Russian]
Drobyshev VA, Loseva MI, Sukharevskaia TM, Michurin AI.
Abstract
The authors present results concerning use of low-frequency magnetic
fields and HF-therapy for correction of vegetative homeostasis in
workers with variable length of service, exposed to vibration, having
early forms of arterial hypertension. The most positive changes of
vegetative status and central hemodynamics are seen in workers with low
length of service.
Therapeutic complexes of physical factors in mild arterial hypertension.
[Article in Russian]
Kniazeva TA, Nikiforova TI.
Three therapeutic complexes were compared clinically in patients with
mild arterial hypertension. Complex 1 consisted of dry air–radon baths,
bicycle exercise and exposure of the renal projection area to
decimetric electromagnetic field. Its efficacy was 90%, mechanism of the
hypotensive action is reduction of enhanced activity of the
sympathico-adrenal and renin-angiotensin-aldosterone systems,
improvement of water-mineral metabolism and lipid peroxidation. Complex 2
consisted of dry effervescent baths, anaprilin electrophoresis with
sinusoidal modulated currents and exposure of the renal projection area
to low-frequency alternating magnetic field. Its efficacy was 80%. It
affects renin-angiotensin-aldosterone system, water-mineral metabolism
and lipid peroxidation. Complex 3 consisted of electric sleep, laser
therapy and general sodium chloride baths. Its efficacy was 63%. The
effect was due to inhibition of high sympathico-adrenal system.
Klin Med (Mosk). 2000;78(3):23-5.
Characteristics of microcirculation and vascular responsiveness in
elderly patients with hypertension and ischemic heart disease.
[Article in Russian]
Abramovich SG.
Microcirculation and vascular responsiveness were studied in 52
patients with arterial hypertension and ischemic heart disease versus 48
healthy elderly persons. The patients were found to have defects of the
end blood flow in all links of microcirculation, longer and more severe
vasoconstriction of conjunctival and skin vessels in response to
norepinephrine and cold stimulation tests.
Combination of EHF therapy + magnetotherapy + drugs results in faster
and persistent hypotensive and analgetic effect compared to standard
drug therapy, potentiates action of vascular drugs on cerebral and
peripheral circulation, reduces dose of hypotensive drugs in patients
with arterial hypertension and vibration disease.
Crit Rev Biomed Eng. 2000;28(1-2):339-47.
The use of millimeter wavelength electromagnetic waves in cardiology.
Lebedeva AYu.
2nd Department of urgent cardiology at State Clinical Hospital, Russian State Medical University, Moscow.
Abstract
This paper concerns the problems of the use of millimeter wavelength
electromagnetic waves for the treatment of cardiovascular disease. The
prospects for this use are considered.
Central hemodynamics, diastolic and pumping functions of the heart,
myocardial reactivity, microcirculation and biological age of
cardiovascular system were studied in 66 elderly patients suffering from
hypertension and ischemic heart disease. The patients received systemic
magnetotherapy which produced a geroprotective effect as shown by
improved microcirculation, myocardial reactivity, central hemodynamics
reducing biological age of cardiovascular system and inhibiting its
ageing.
Neuropsychobiology. 1998 Nov;38(4):251-6.
No effects of pulsed high-frequency electromagnetic fields on heart rate variability during human sleep.
Mann K, Roschke J, Connemann B, Beta H.
Department of Psychiatry, University of Mainz, Germany.
The influence of pulsed high-frequency electromagnetic fields emitted
by digital mobile radio telephones on heart rate during sleep in
healthy humans was investigated. Beside mean RR interval and total
variability of RR intervals based on calculation of the standard
deviation, heart rate variability was assessed in the frequency domain
by spectral power analysis providing information about the balance
between the two branches of the autonomic nervous system. For most
parameters, significant differences between different sleep stages were
found. In particular, slow-wave sleep was characterized by a low ratio
of low- and high-frequency components, indicating a predominance of the
parasympathetic over the sympathetic tone. In contrast, during REM sleep
the autonomic balance was shifted in favor of the sympathetic activity.
For all heart rate parameters, no significant effects were detected
under exposure to the field compared to placebo condition. Thus, under
the given experimental conditions, autonomic control of heart rate was
not affected by weak-pulsed high-frequency electromagnetic fields.
Paravertebral exposure to infrared radiation (0.87 micron, 5 mW) and
permanent magnetic field in combination with one- and two-semiperiodic
alternative magnetic fields (50 Hz, 15-30 mT) was studied in respect to
the action on adaptive reactions in animals with experimental
atherosclerosis. Complex consisting of infrared radiation, permanent
magnetic field and one-semiperiodic pulse alternative magnetic field was
most effective in restoration of vasomotor-metabolic and immune
disturbances accompanying development of atherosclerosis.
Bioelectromagnetics. 1998;19(2):98-106.
Nocturnal exposure to intermittent 60 Hz magnetic fields alters human cardiac rhythm.
Heart rate variability (HRV) results from the action of neuronal and
cardiovascular reflexes, including those involved in the control of
temperature, blood pressure and respiration. Quantitative spectral
analyses of alterations in HRV using the digital Fourier transform
technique provide useful in vivo indicators of beat-to-beat variations
in sympathetic and parasympathetic nerve activity. Recently, decreases
in HRV have been shown to have clinical value in the prediction of
cardiovascular morbidity and mortality. While previous studies have
shown that exposure to power-frequency electric and magnetic fields
alters mean heart rate, the studies reported here are the first to
examine effects of exposure on HRV. This report describes three
double-blind studies involving a total of 77 human volunteers. In the
first two studies, nocturnal exposure to an intermittent, circularly
polarized magnetic field at 200 mG significantly reduced HRV in the
spectral band associated with temperature and blood pressure control
mechanisms (P = 0.035 and P = 0.02), and increased variability in the
spectral band associated with respiration (P = 0.06 and P = 0.008). In
the third study the field was presented continuously rather than
intermittently, and no significant effects on HRV were found. The
changes seen as a function of intermittent magnetic field exposure are
similar, but not identical, to those reported as predictive of
cardiovascular morbidity and mortality. Furthermore, the changes
resemble those reported during stage II sleep. Further research will be
required to determine whether exposure to magnetic fields alters stage
II sleep and to define further the anatomical structures where
field-related interactions between magnetic fields and human physiology
should be sought.
A comparative evaluation of the effect of an extremely
high-frequency electromagnetic field on cerebral hemodynamics in
hypertension patients exposed in different reflexogenic areas.
[Article in Russian]
Sokolov BA, Bezruchenko SV, Kunitsyna LA.
A single session and multiple sinocarotid and temporal exposures to
EHF electromagnetic field in patients with stage I and II hypertension
had different effects on cerebral circulation Variants of the above
treatment are proposed.
Study of the efficacy of a course of exposures to travelling pulsed
magnetic field and magnetic laser sessions in 97 patients with stages
I-II essential hypertension showed a high efficacy of travelling pulsed
magnetic field in patients with hyperkinetic hemodynamics and initially
just slightly shifted blood rheology and platelet hemostasis. Magnetic
laser therapy is more effective in patients with eukinetic and
hypokinetic hemodynamics and initially sharply expressed disorders of
blood rheology and platelet hemostasis.
Biofizika. 1996 Jul-Aug;41(4):944-8.
Effect of a “running” pulse magnetic field on certain humoral
indicators and physical ability to work in patients with
neurocirculatory hypo- and hypertension.
[Article in Russian]
Orlov LL, Pochechueva GA, Makoeva LD.
The influence of “running” impulse magnetic field in patients with
neurocirculatory hypo- and hypertension was studied. It has been
determined that magnetotherapy in all patients increased physical load
tolerability and at the same time produced different effects on
hemodynamics (lowering blood pressure in hypertension and increasing it
in hypotension). In patients with neurocirculatory hypotension the
slightly expressed positive clinical effect was obtained, that makes
“running” impulse magnetic field therapy useless in this pathology. At
the same time in patients with neurocirculatory hypertension “running”
impulse magnetic field therapy resulted in significant improvement of
physical tolerability, improvement of patients general condition, blood
pressure decrease, lowering of pressor power generation concentration,
correcting effect on aldosterone blood content. These data witness for
the usefulness of this method in treatment of patients with
neurocirculatory hypertension.
Ter Arkh. 1996;68(5):63-7.
The therapeutic correction of disorders in thrombocyte-vascular
hemostasis and of changes in the rheological properties of the blood in
patients with arterial hypertension.
[Article in Russian]
Zadionchenko VS, Bagatyrova KM, Adasheva TV, Timofeeva NIu, Zaporozhets TP.
158 patients with essential hypertension received beta-adrenoblockers
and were exposed to travelling impulse magnetic field, magnetolaser
radiation. The study of platelet-vessel hemostasis and blood rheology
revealed a relation of good clinical response and increased exercise
tolerance with initial platelet dysfunction and rheological disorders
which underwent positive changes in the course of treatment
The effect of exposure to magnetics and lasers on the clinical
status and the electrophysiological indices of the heart in patients
with cardiac arrhythmias.
Magnetolaser radiation has a considerable influence on
electrophysiological condition of the sinus node and sinoatrial zone.
There are cases when patients with sick sinus syndrome get rid of
arrhythmia. The treatment is safe and promising for further studies.
Vestn Khir Im I I Grek. 1996;155(5):37-9.
The potentials of laser and electromagnetic-laser therapy in the
treatment of patients with arteriosclerosis obliterans of the vessels of
the lower extremities.
[Article in Russian]
Galimzianov FV.
A comparative analysis of the laser and electromagnetic laser therapy
was performed in the complex treatment of patients with obliterating
atherosclerosis of the lower extremity vessels. Laser treatment exerts a
therapeutic effect related with its influence upon microcirculation.
The effectiveness of complex treatment becomes higher when using a
combination of laser therapy with the impulse electromagnetic therapy of
complex modulation at the expense of improvement of the regional blood
circulation in all links of the vasculature.
The effect of a low-frequency alternating magnetic field on the autonomic system in children with primary arterial hypertension.
[Article in Russian]
Konova OM, Khan MA.
The paper provides cardiointervalographic data assessing autonomic
nervous system (ANS) function in children with primary arterial
hypertension exposed to low-frequency alternating magnetic field.
Favourable effects of such magnetotherapy manifest in attenuation of
sympathetic and vagotonic symptoms.
Lik Sprava. 1996 Jan-Feb;(1-2):58-62.
The clinico-biochemical, functional, immunological and cellular
characteristics of the body reactions in patients with the initial
stages of hypertension to the effect of a magnetic field.
[Article in Ukrainian]
Myloslavs’kyi DK, Koval’ SM, Sheremet MS.
The article presents a comprehensive evaluation of major clinical,
laboratory and functional indices in the time course of magnetotherapy
as well as during administration of such treatments. The most promising
alternative appears to be that involving the use of immunologic and
cellular parameters as markers of efficacy of therapeutic action of
magnetic fields in early stages of hypertensive disease. Causes for
effectiveness and ineffectiveness of the above treatment option are
analyzed, approaches to eliminating those are outlined, the main
indications and contraindications are determined, merits and demerits of
magnetotherapy are drawn attention to.
The effect of the joint use of plasmapheresis and magnetic treatment
of the blood on the indices of blood rheology and hemodynamics in
hypertension patients.
[Article in Russian]
Alizade IG, Karaeva NT.
The results are presented obtained on combined application of
plasmapheresis and magnetic blood treatment as regards hemorheology and
hemodynamics in 41 patients with essential hypertension stage II. The
course introduction of the above combined treatment led to positive
shifts in arterial pressure irrespective of the patients’ hemodynamic
type, in blood density, elasticity and dynamic properties.
The efficacy of low-intensity exposures in hypertension.
[Article in Russian]
Kniazeva TA, Otto MP, Markarov GS, Donova OM, Markarova IS.
One hundred hypertensive subjects with labile and stable disease were
exposed to low-intensity low-frequency electrostatic field generated by
the unit “Infita-A”. In labile hypertension, the field produces a
hypotensive effect, improves myocardial contractility, increases
myocardial and coronary reserves due to reduced peripheral resistance
and stimulation of myocardial propulsion. Therapeutic response to the
treatment is attributed to normalization of deep brain structure
functioning.
The effect of a low-frequency magnetic field on erythrocyte membrane
function and on the prostanoid level in the blood plasma of children
with parasystolic arrhythmia.
As shown by clinical and biochemical evidence on 23 parasystolic
children, the treatment with low-frequency magnetic field improves
humoral and cellular processes participating in cardiac rhythm
regulation. There is activation of Ca, Mg-ATPase in the red cells, a
reduction of plasma thromboxane levels. Red cell phospholipid
composition insignificantly change. Further courses of magnetotherapy
may lower the risk of recurrent arrhythmia.
Changes in intracellular regeneration and the indices of endocrine
function and cardiac microcirculation in exposure to decimeter waves.
[Article in Russian]
Korolev IuN, Geniatulina MS, Popov VI.
Abstract
An electron-microscopic study of rabbit heart with experimental
myocardial infarction revealed that extracardiac exposure to decimetric
waves (DW) activated intracellular regeneration in the myocardium. This
was associated with enhanced circulation and endocrine activity in the
heart. Most pronounced regeneration was registered in adrenal exposure,
the effect of the parietal exposure being somewhat less.
The paper presents the results of treatment received by 60 patients
suffering from lower limb vascular obliteration stage IIA-III. The
treatment involved combined use of magnetic field and laser irradiation.
Peripheral circulation and central hemodynamics were evaluated
rheographically and using ultrasound Doppler sphygmomanometry. Combined
application of the above two modalities produced a greater effect on
central hemodynamics compared to them introduced alone.
Ter Arkh. 1993;65(1):44-9.
The comparative efficacy of nondrug and drug methods of treating hypertension.
[Article in Russian]
Ivanov SG.
Effectiveness of some physical therapeutic factors (constant magnetic
field, impulse currents) and new hypotensive drugs (tobanum, prinorm,
ormidol, minipress, arifon, arilix) was compared in the treatment of
essential hypertension stage II. It is suggested that nonpharmaceutical
therapy can regulate functions, correct hemodynamic and microcirculatory
disorders, produce therapeutic effect without side effects typical for
drugs.
Lik Sprava. 1992 May;(5):40-3.
The effect of combined treatment with the use of magnetotherapy on
the systemic hemodynamics of patients with ischemic heart disease and
spinal osteochondrosis.
[Article in Russian]
Dudchenko MA, Vesel’skii ISh, Shtompel’ VIu.
The authors examined 66 patients with ischemic heart disease and
concomitant cervico-thoracic osteochondrosis and 22 patients without
osteochondrosis. Differences were revealed in values of the systemic
hemodynamics with prevalence of the hypokinetic type in patients with
combined pathology. Inclusion of magnetotherapy in the treatment complex
of patients with ischemic heart disease and osteochondrosis favours
clinical improvement, normalization of indices of central and regional
blood circulation.
Lik Sprava. 1992 Oct;(10):32-5.
A comparative evaluation of the efficacy of quantum methods for treating hypertension patients.
[Article in Ukrainian]
Nykul TD, Karpenko VV, Voitovych NS, Karmazyna OM.
A study is presented of the effect of laser and microwave resonance
therapy on the hemodynamics and hemorheology in 56 patients with
hypertensive disease. The hypotensive effect of intravascular laser
therapy is related to the positive changes, reduction of blood viscosity
and general peripheral vascular resistance. The effect of low molecular
electromagnetic radiation on acupuncture points favoured clear
reduction of peripheral vessel resistance. Combination of laser and
microwave resonance therapy produces a positive effect due to
potentiation of these methods and, thus, influencing the systems of
hemodynamics, hemostasis and hemorheology.
The effect of decimeter waves on the metabolism of the myocardium
and its hormonal regulation in rabbits with experimental ischemia.
[Article in Russian]
Frenkel’ ID, Zubkova SM, Liubimova NN, Popov VI.
Abstract
Biochemical and morphometric methods were employed to study the
effect of decimetric waves (460 MHz, 10 and 120 mW/cm2) in cardiac and
thyroid exposure on oxygen metabolism, myocardial microcirculation and
contractility, thyroid and adrenal hormonal activity, kallikrein-kinin
system activity in rabbits with experimental myocardial ischemia.
Hypoxia discontinued in all the treatment regimens, but the exposure of
the heart (field density 10 mW/sm2) had the additional effect on lipid
peroxidation which reduced in the serum and normalized in the
myocardium, on myocardial contractility, kallikrein-kinin system and on
the adrenal and thyroid hormones.
The investigators have developed a polymagnetic system “Avrora-MK-01”
employing running impulse magnetic field to treat diseases of the leg
vessels by the action on peripheral capillary bed. At a pregangrene
stage a positive effect on peripheral capillaries was achieved in 75-82%
of the patients treated.
Kardiologiia. 1991 Feb;31(2):67-70.
Optimization of the treatment of patients with hypertensive disease from the rheological viewpoint.
[Article in Russian]
Shabanov VA, Kitaeva ND, Levin GIa, Karsakov VV, Kostrov VA.
The efficacy of various modes of correcting rheological disorders
(membrane-protective agents, laser irradiation, plasmapheresis was
compared in hypertensive patients. In 30% of the patients, the
conventional antihypertensive therapy was demonstrated to deteriorate
hemorheological parameters, which was due to its atherogenic impact on
the blood lipid spectrum. Essential phospholipids, laser irradiation,
and plasmapheresis, which are supplemented to the multimodality therapy
promote a significant improvement of hemorheological parameters, which
makes it possible to recommend them for management of hypertensive
patients with a stable (essential phospholipids), complicated (laser
irradiation), and refractory (plasmapheresis) course.
Khirurgiia (Mosk). 1990 Nov;(11):41-3.
Outpatient electromagnetic therapy combined with hyperbaric oxygenation in arterial occlusive diseases.
[Article in Russian]
Reut NI, Kononova TI.
The authors first applied hyperbaric oxygenation (HBO) in the
outpatient clinic in 1968. Barotherapy was conducted in 107 outpatients
whose ages ranged from 27 to 80 years; they had various stages of the
disease of 5- to 20-year history. In 70 patients treated for
obliterating diseases of the vessels by HBO in a complex with
magnetotherapy by means of magnetophors, the remission lasted 1-2 years;
patients treated by HBO alone had a 3-8 month remission. A prolonged
positive effect was produced in 64 patients. The suggested effective and
safe method is an additional one to the existing means of treating this
serious and progressive disease, which can be applied successfully in
outpatient clinics.
A study was made of the influence of the constant MKM2-1 magnets on
patients suffering from essential hypertension. Continuous action of the
magnetic field, created by such magnets, on the patients with stage II
essential hypertension was noted to result in a decrease of arterial
pressure without the occurrence of any side effects and in a
simultaneous reduction of the scope of drug administration. Apart from
that fact, magnetotherapy was discovered to produce a beneficial effect
on the central hemodynamics and microcirculation. The use of the MKM2-1
magnets may be regarded as a feasible method of the treatment of
essential hypertension patients at any medical institution.
Patol Fiziol Eksp Ter. 1989 May-Jun;(3):59-61.
Changes of central hemodynamics in rats with spontaneous hypertension under the effect of a low-frequency magnetic field.
[Article in Russian]
Buiavykh AG, Stukanov AF.
It was established that a course of exposures of the renal region of
rats with spontaneous hypertension to the effect of low-frequency
magnetic field influenced the central hemodynamic parameters
significantly, which was displayed by reduction of total peripheral
vascular resistance and normalization of the cardiac output.
1
a Department of Mathematical and
Informatics Sciences , Physical Sciences and Earth Sciences of Messina
University , Messina , Italy.
2
e CISFA – Interuniversity Consortium
of Applied Physical Sciences (Consorzio Interuniversitario di Scienze
Fisiche Applicate) , Messina , Italy.
3
b Le Studium, Loire Valley Institute for Advanced Studies, Orléans & Tours , Orléans , France.
4
c Centre de Biophysique Moleculaire
(CBM), rue Charles Sadron, Laboratoire Interfaces, Confinement,
Matériaux et Nanostructures (ICMN) – UMR 7374 CNRS , Université
d’Orléans , Orleans , France.
5
d Istituto Nazionale di Alta Matematica “F. Severi” – INDAM – Gruppo Nazionale per la Fisica Matematica – GNFM , Rome , Italy.
Abstract
Samples of human hemoglobin, bovine
serum albumin, lysozyme and myoglobin were used as prototype of proteins
to investigate their response to exposure to high frequency
electromagnetic fields (HF-EMFs), in order to study possible application
to the treatment of cancer. To this aim, Fourier-transform infrared
spectroscopy was used in the infrared region. The most evident result
which appeared after 3 h exposure to HF-EMFs was a significant increase
in intensity of the Amide I band and of CH2 bending
vibrations, showing that the proteins aligned toward the direction of
the field. In addition, proteins’ unfolding and aggregation occurred
after exposure to HF-EMFs. These findings can be explained assuming a
resonance interaction between the natural frequencies of proteins and
HF-EMFs, which can induce iperpolarization of cells. Given that
cancerous tissues were found to have natural frequencies different from
natural frequencies of normal tissues, we can hypothesize to irradiate
cancerous tissues using EMFs at natural frequencies of cancer cells,
causing resonant interaction with cellular membrane channels, inducing
increasing of ions’ flux across cellular channels and damaging the
cellular functions of cancer cells.
KEYWORDS:
Electromagnetic fields; FTIR spectroscopy; cancer treatment; membrane channel; proteins; resonanceIntegr Biol (Camb). 2017 Dec 11;9(12):979-987. doi: 10.1039/c7ib00116a.
High-frequency irreversible electroporation targets resilient tumor-initiating cells in ovarian cancer.
Rolong A1, Schmelz EM, Davalos RV.
Author information
1
Virginia Tech – Wake Forest University School of Biomedical Engineering and Sciences, Blacksburg, VA 24061, USA. davalos@vt.edu.
Abstract
We explored the use of irreversible
electroporation (IRE) and high-frequency irreversible electroporation
(H-FIRE) to induce cell death of tumor-initiating cells using a mouse
ovarian surface epithelial (MOSE) cancer model. Tumor-initiating cells
(TICs) can be successfully destroyed using pulsed electric field
parameters common to irreversible electroporation protocols.
Additionally, high-frequency pulses seem to induce cell death of TICs at
significantly lower electric fields suggesting H-FIRE can be used to
selectively target TICs and malignant late-stage cells while sparing the
non-malignant cells in the surrounding tissue. We evaluate the
relationship between threshold for cell death from H-FIRE pulses and the
capacitance of cells as well as other properties that may play a role
on the differences in the response to conventional IRE versus H-FIRE
treatment protocols.
Sci Rep. 2016 Jan 29;6:19451. doi: 10.1038/srep19451.
Constructal approach to cell membranes transport: Amending the ‘Norton-Simon’ hypothesis for cancer treatment.
Lucia U1, Ponzetto A2, Deisboeck TS3,4.
Author information
1Dipartimento Energia, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
2Department of Medical Sciences, University of Torino, Corso A.M. Dogliotti 14, 10126 Torino, Italy.
3Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA.
4ThinkMotu LLC, Wellesley, MA 02481, USA.
Abstract
To investigate biosystems, we propose a new thermodynamic concept
that analyses ion, mass and energy flows across the cell membrane. This
paradigm-shifting approach has a wide applicability to medically
relevant topics including advancing cancer treatment. To support this
claim, we revisit ‘Norton-Simon’ and evolving it from an already
important anti-cancer hypothesis to a thermodynamic theorem in medicine.
We confirm that an increase in proliferation and a reduction in
apoptosis trigger a maximum of ATP consumption by the tumor cell.
Moreover, we find that positive, membrane-crossing ions lead to a
decrease in the energy used by the tumor, supporting the notion of their
growth inhibitory effect while negative ions apparently increase the
cancer’s consumption of energy hence reflecting a growth promoting
impact. Our results not only represent a thermodynamic proof of the
original Norton-Simon hypothesis but, more concretely, they also advance
the clinically intriguing and experimentally testable, diagnostic
hypothesis that observing an increase in negative ions inside a cell in
vitro, and inside a diseased tissue in vivo, may indicate growth or
recurrence of a tumor. We conclude with providing theoretical evidence
that applying electromagnetic field therapy early on in the treatment
cycle may maximize its anti-cancer efficacy.
J Orthop Surg Res. 2015; 10: 104.
Published online 2015 Jul 7. doi: 10.1186/s13018-015-0247-z
PMCID: PMC4496869
Nanosecond pulsed electric field inhibits proliferation and induces apoptosis in human osteosarcoma
Xudong Miao,# Shengyong Yin,# Zhou Shao, Yi Zhang, and Xinhua Chen
The Department of Orthopedics, the Second Affiliated Hospital, Zhejiang University, Hangzhou, Zhejiang Province 310003 China
The Department of Hepatobiliary and
Pancreatic Surgery, the First Affiliated Hospital, Zhejiang University,
Collaborative Innovation Center for Diagnosis Treatment of Infectious
Diseases, 79 Qinchun Road, Hangzhou, Zhejiang Province 310003 China
The Department of Gynecology, The First
Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou,
Zhejiang Province 310000 China
Xinhua Chen, Phone: +86-571-87236570, Email: nc.ude.ujz@nehc_auhnix.
Recent studies suggest that
nanosecond pulsed electric field (nsPEF) is a novel minimal invasive and
non-thermal ablation method that can induce apoptosis in different
solid tumors. But the efficacy of nsPEF on bone-related tumors or bone
metastasis is kept unknown. The current study investigates antitumor
effect of nsPEF on osteosarcoma MG-63 cells in vitro.
Method
MG-63 cells were treated with nsPEF
with different electric field strengths (0, 10, 20, 30, 40, and 50
kV/cm) and different pulse numbers (0, 6, 12, 18, 24, and 30 pulses).
The inhibitory effect of nsPEF on the growth of MG-63 cells was measured
by Cell Counting Kit-8 (CCK-8) assay at different time points (0, 3,
12, 24, and 48 h post nsPEF treatment). The apoptosis was analyzed by
Hoechst stain, in situ terminal deoxynucleotidyl transferase
(TdT)-mediated dUTP nick-end labeling (TUNEL), and flow cytometric
analysis. The expression of osteoprotegerin (OPG), receptor activator of
NF-kB ligand (RANKL), and tumor necrosis factor a (TNF-a) was examined
by reverse-transcription polymerase chain reaction (RT-PCR) and western
blot.
Results
The CCK-8 assay showed that nsPEF
induced a distinct electric field strength- and pulse number-dependent
reduction of cell proliferation. For treatment parameter optimizing, the
condition 40 kV/cm and 30 pulses at 24 h post nsPEF achieved the most
significant apoptotic induction rate. Hoechst, TUNEL, and flow
cytometric analysis showed that the cell apoptosis was induced and cells
were arrested in the G0/G1 phase. PCR and western blot analysis
demonstrated that nsPEF up-regulated OPG expression had no effect on
RANKL, increased OPG/RANKL ratio.
Conclusion
NsPEF inhibits osteosarcoma growth,
induces apoptosis, and affects bone metabolism by up-regulating OPG,
indicating nsPEF-induced apoptosis in osteosarcoma MG-63 cells. NsPEF
has potential to treat osteosarcoma or bone metastasis. When nsPEF is
applied on metastatic bone tumors, it might be beneficial by inducing
osteoblastic differentiation without cancer proliferation. In the
future, nsPEF might be one of the treatments of metastatic bone tumor.Keywords: Osteosarcoma, MG-63 cells, Nanosecond pulsed electric field, Apoptosis
Introduction
Osteosarcoma is a malignant bone tumor
with high occurrence in children and young adolescents. Retrospective
review showed that in the past 30 years, osteosarcoma had a poor
prognosis and there was no significant improvement of disease-free
survival and the stagnated situation has not improved even with the
aggressive use of neoadjuvant chemotherapy and radiation therapy [1].
Patients did not benefit from overtreatment, and as a result, a high
rate of lung metastasis, recurrence, and pathological fracture
frequently occur, keeping osteosarcoma still one of the lowest survival
rates in pediatric cancers [2]. Thus, new therapeutic strategy needs to be developed.
Nanosecond pulsed electric field (nsPEF) is an innovative
electric ablation method based on high-voltage power technology, which
came into medical application in the last decade [3].
NsPEF accumulates the electric field energy slowly and releases it into
the tumor in ultra-short nanosecond pulses, altering electrical
conductivity and permeability of the cell membrane, causing both cell
apoptosis and immune reaction [4].Quite
different from any other traditional local ablation method, nsPEF
accumulate less Joule heating and showed no hyperthermic effects [5],
indicating unique advantage over other thermal therapies such as
radiofrequency, cryoablation, microwave, and interstitial laser; nsPEF
can be used alone and so avoid the side effect caused by chemotherapy or
percutaneous ethanol injection [6].
We have used nsPEF to ablate tumor and showed the equal outcome as the radical resection with proper indication [7].
Clinical trials and pre-clinical studies from different groups proved
that nsPEF has direct antitumor effects by inhibiting proliferation and
causing apoptosis in human basal cell carcinoma [8, 9], cutaneous papilloma, squamous cell carcinoma [10], melanoma [11, 12], hepatocellular tumor [13], pancreatic tumor [14], colon tumor [15, 16], breast cancer [17, 18], salivary adenoid cystic carcinoma [19], oral squamous cell carcinoma [20],
et al. Local ablation with nsPEF indicates the noticeable advantage of
not only eliminating original tumors but also inducing an immune
reaction, e.g., enhance macrophage [21] and T cell infiltration [22] and induce an immune-protective effect against recurrences of the same cancer [23]. The characteristic of electric field on bone metabolism [24] is extremely helpful for osteosarcoma patients with pathological fracture which leads to poor prognosis [25, 26].
Considering osteosarcoma is especially prevalent in children and young adults during quick osteoblastic differentiation [1, 2], unstable RB gene and p53 gene are commonly involved in this malignant transformation process [27];
we hypothesize that nsPEF affects osteosarcoma growth by targeting the
Wnt/?-catenin signaling pathway, a key signaling cascade involved in
osteosarcoma pathogenesis. Here, we investigate nsPEF-induced changes on
human osteosarcoma MG-63 cells to determine (1) the dose-effect
relationship and time-effect relationship of nsPEF on osteosarcoma cell
growth and apoptosis induction and (2) the nsPEF effect on the
osteosarcoma cell; osteoblast specific gene and protein expression
(receptor activator of NF-?B ligand (RANKL) and osteoprotegerin (OPG))
were measured along with the production of the pro-inflammatory cytokine
tumor necrosis factor a (TNF-a).
Materials and methods
Cell lines and cell culture
MG-63 human osteosarcoma cells were
purchased from the Cell Bank of Chinese Academy of Sciences (Shanghai,
China), cultured in Dulbecco’s Modified Eagle’s medium (DMEM, Gibco
Invitrogen, Carlsbad, CA, USA) supplemented with 10 % fetal bovine serum
(FBS, SAFC Biosciences, Lenexa, KS, USA), 100 units/mL penicillin, and
100 mg/mL streptomycin (Sigma, Aldrich, St. Louis, MO, USA). Cells were
kept in a humidified atmosphere of 5 % CO2 at 37 °C.
The nsPEF treatment and dose-effect exam
The nsPEF treatment system was made
by Leibniz Institute for Plasma Science and Technology, Germany, and an
nsPEF generator with duration of 100 ns was applied. Varied electric
fields were released in a cell treatment system from 10 to 60 kV/cm.
Waveforms were monitored with a digital phosphor oscilloscope (DPO4054,
Tektronix, USA) equipped with a high voltage probe (P6015A, Tektronix,
USA). MG-63 human osteosarcoma cells were harvested with trypsin and
resuspended in fresh DMEM with 10 % FBS to a concentration of 5.0 × 106
cells/mL. Five hundred microliters of cell suspension were placed into a
sterile electroporation cuvette (Bio-Rad, US, 0.1-cm gap). Cells were
exposed to 100 pulses at 0, 10, 20, 30, 40, 50, and 60 kV/cm electric
field strengths, respectively. Under the 50 kV/cm electric field
strength, the different pulse numbers were applied (0, 6, 12, 18, 24,
and 30 pulses). The experiments were repeated for three times. After
incubation for 24 h, cells were calculated by Cell Counting Kit-8
(CCK-8) assay (Dojindo Laboratories, Kumamoto, Japan).
Measurement of apoptosis with TUNEL assay, Hoechst stain, and flow cytometry
At different hours after nsPEF
treatment (40 kV/cm, 30 pulses), the treated cells were incubated for 0,
3, 12, 24, and 48 h to determine single-cell apoptosis using the assay
of terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end
labeling (TUNEL) with In Situ Cell Death Detection Kit (Millipore, USA)
and Hoechst stain kit (Beyotime, Shanghai, China) according to the
manufacturer’s instruction, as previously described [14].
Under different electric field strengths and with different pulses, the
treated cells were incubated for 24 h to detect cell apoptosis by
Annexin V-FITC Apoptosis Detection Kit (BD Biosciences). The cell cycle
was also analyzed as previously described [14].
Reverse-transcription polymerase chain reaction
Reverse-transcription polymerase
chain reaction (RT-PCR) was performed for assessing the expression of
OPG, RANKL, and TNF-a. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH),
a house keeping gene, was used as the internal control to calculate the
comparative expression. Total RNA was extracted using TRIzol reagent
(Sangon, Shanghai, China). The first strand cDNA synthesis from 1 mg of
RNA was performed using SuperScript II Reverse Transcriptase
(Invitrogen) and Oligo dT primer (Promega, Madison, WI, USA) according
to the manufacturer’s instructions. PCR was performed using the
oligunucleotides listed as the following. The specific primers were made
by Sangon, Shanghai, China, which were listed as the following: RANK:
F: CAGGAGACCTAGCTACAGA, R: CAAGGTCAAGAGCATGGA, 95 °C, 1 min; 55 °C, 1
min; 72 °C, 1 min; OPG (264 bp): F: AGTGGGAGCAGAAGACAT, R: TGGA
CCTGGTTACCTATC, 95 °C, 1 min; 57 °C, 1 min; 72 °C, 1 min; TNF-a: F:
GTGGCAGTCTCAAACTGA, R: TATGGAAAGGGGCACTGA, 94 °C, 40 s; 55 °C, 40 s; 72
°C, 40 s; GAPDH: F: CAG CGACACCCACTCCTC, R: TGAGGTCCA CCACCCTGT, 94 °C, 1
min; 57 °C, 1 min; 72 °C, 1 min.
Western blotting analysis
MG-63 cells (5 × 105)
were plated and treated with different doses of nsPEF. Cells were then
lysed with a lysis buffer and then quantified. The equal amounts of
protein were loaded, and electrophoresis was applied on a 12 % sodium
dodecyl sulfate-polyacrylamide gel electrophoresis mini-gel. Proteins
were transferred to a PVDF membrane and blocked with casein PBS and 0.05
% Tween-20 for 1 h at room temperature. Membranes were incubated with
mouse monoclonal OPG, anti-OPG (1:500), RANKL (1:200), TNF-a (1:300),
GAPDH (1:1000) antibodies which were purchased from Santa Cruz (Santa
Cruz Biotechnology, Santa Cruz, CA, USA). Horseradish
peroxidase-conjugated secondary antibody was purchased from Zhongshan
(Zhongshan Golden Bridge, Beijing, China.). The protein expression was
visualized with enhanced chemiluminescence reagent (ECL kit, Amersham,
UK).
Statistical analysis
Statistical significance was determined using Student’s t test, using SPSS 13.0. P < 0.05 was considered to indicate a statistically significant result.
Results
NsPEF parameter optimizing by CCK-8 and flow cytometry
CCK-8 assay was used to calculate
the IC50 values, and flow cytometry was used to detect apoptosis. There
were significant growth inhibition and apoptosis induction in a
dose-dependent manner following nsPEF treatment for 24 h. MG-63 cell
growth was inhibited in an electric field strength- and pulse
number-dependent manner. There was significant (P > 0.001) growth inhibition when electric field strength was 40–50 kV/cm (Fig. 1a) and when pulse number was 30 (Fig. 1d)
vs control. Cells were treated by nsPEF and then incubated for 24 h.
Apoptotic and dead cells were analyzed by flow cytometry using dual
staining with propidium iodide (PI) and Annexin V-FITC. NsPEF induced
viable apoptotic cells stained with Annexin. The apoptotic cell rate is
significantly increased when electric field strength was 40–50 kV/cm
(Fig. 1b, c) and when pulse number was 30 (Fig. 1e, f).
Fig. 1
NsPEF treatment parameter optimizing by CCK-8 and flow cytometry.
After 24 h post nsPEF, CCK-8 assay was used to calculate the IC50 values
under different electric field strengths (a) and different pulse numbers (d). The flow cytometry was used to detect …
Apoptosis induction at different times post nsPEF treatment
To determine the effects of nsPEF
on the induction of apoptosis in MG-63 cells, the Annexin V assay was
performed. After 40 kV/cm and 30 pulses of nsPEF treatment, the control
and treated cells were stained with Hoechst 33528 (Fig. 2a upper lane) and TUNEL (Fig. 2a lower lane). The statistical analysis of the positive apoptotic cells were counted and shown in Fig. 2b
at different hours (0, 3, 12, 24, and 48 h). Apoptotic cells induced by
nsPEF treatment were recognized by terminal deoxynucleotidyl
transferase (TdT)-mediated dUTP nick-end labeling (TUNEL), detecting DNA
fragmentation by labeling the terminal end of nucleic acids. The number
or percentages of apoptotic cells detected following nsPEF treatment
was shown in Fig. 2b.
The quantitative analysis showed the percentages of apoptotic cells
detected following nsPEF treatment which were 2.6 % (0 h), 8.8 % (3 h),
21 % (12 h), 42 % (24 h), and 15 % (48 h) without nsPEF treatment. The
apoptotic induction 12 and 24 h post nsPEF treatment showed significance
(P = 0.01243, 0.00081, respectively, vs control). The cell cycle was analyzed by flow cytometry (Fig. 2c) and statistically analyzed in Fig. 2d, which indicates that nsPEF arrest cells in the G0/G1 phase (Fig. 2d).
Fig. 2
Apoptosis induction at different times post nsPEF treatment. After
40 kV/cm and 30 pulses of nsPEF treatment, the control and treated cells
were stained with Hoechst 33528 (aupper lane) and TUNEL (alower lane). The statistical analysis of the positive …
The effect of nsPEF on OPG/RANKL, TNF-? gene, and protein expression
With 30 pulses, 24 h post
treatment, PCR and western blot were used to determine the different
electric field strengths on cell OPG/RANKL, TNF-? gene (Fig. 3a), and the corresponding protein expression (Fig. 3b). NsPEF significantly increased OPG transcription and protein expression at 20–50 kV/cm (Fig. 3a, c). RANKL was almost undetectable both in the control and nsPEF-treated MG-63 cells (Fig. 3a, c). NsPEF slightly down-regulated TNF-a (Fig. 3a, c).
The OPG is important in the regulation of bone formation. PCR results
showed that the nsPEF-treated cells demonstrated a significantly
up-regulation of OPG transcription. Western blot analysis confirmed that
nsPEF stimulated osteoprotegerin protein production in the MG-63 cells.
Fig. 3
The nsPEF effect on gene and protein expression. With 30 pulses, 24
h post treatment, PCR and western blot were used to determine the
different electric field strengths on cell OPG/RANKL, TNF-a gene (a), and protein expression (b). NsPEF significantly …
Discussion
The primary bone malignancy osteosarcoma
is still a challenge for orthopedics. For patients who are not suitable
for radical resection, the minimal invasive ablation techniques can be
used as an alternative to surgery. NsPEF has been proved to be a novel
non-thermal ablation method which can activate a protection immune
response [21–23].
According to the Clinical Practice Guidelines in Oncology of the
National Comprehensive Cancer Network (NCCN), local ablation can be used
for curative or palliative intent, either alone or in combination with
immunotherapy or chemotherapy [11]. The effect of systemic chemotherapy may be enhanced by the physiological changes produced by ablation [11]. Furthermore, ablation can sometimes be used as a complement to surgery [13].
A number of studies have demonstrated that local ablation is effective in osteosarcoma [28–30].
To our best knowledge, the application of nsPEF in osteosarcoma has
never been reported. The bone-related tumor study is extremely important
because many solid tumors tend to have metastasis in bones. The present
study applies a new ablation methodology in osteosarcoma and identifies
its molecular target. Our data suggest that nsPEF had direct effects on
osteosarcoma cells, including the inhibition of tumor cell
proliferation and induction of apoptosis. These results are consistent
with previous reports. NsPEF inhibits cell proliferation and induces
apoptosis in tumor cells [11, 16].
The development of osteoclasts is controlled by cytokine
synthesized by osteoblasts like receptor activator of NF-?B ligand
(RANKL), osteoprotegerin (OPG), and tumor necrosis factor ? (TNF-a) [31].The
extension of the current study is the investigation of nsPEF’s effect
on bone resorption when nsPEF is in its ablation dosage. OPG is a member
of the tumor necrosis factor receptor family. It has multiple
biological functions such as regulation of bone turnover. OPG can block
the interaction between RANKL and the RANK receptor [31].
NsPEF increased OPG expression in MG-63 in in vitro assays. Our data
indicate that nsPEF up-regulated the OPG expression. Bone remodeling can
be assessed by the relative ratio of OPG to RANKL [32].
NsPEF had no effect on RANKL expression. Defined as a potent
bone-resorbing factor, TNF-a is responsible for stimulating bone
resorption. TNF-? exerts its osteoclastogenic effect by activating NF-?B
with RANKL [33].
Our results show that in osteosarcoma MG-63, in addition to apoptosis
induction, nsPEF can regulate bone metabolism through adjusting
OPG/RANKL ratio.
TNF-a expression still needs further
investigation due to the weak expression. But, it is the key cytokine
that we assume which would change the local inflammatory
microenvironment in the ablation zone.
The limit of the current study
In this in vitro study, the MG-63
osteosarcoma cell line is used as a model system. Therefore, results
obtained from cultured cells only gave hints for the nsPEF treatment of
osteosarcoma. The current results need to be tested in an in vivo
osteosarcoma model, e.g., MG-63 cell xenografts.
Conclusion
NsPEF can be considered as a
potential therapeutic intervention to suppress bone remodeling and
osteoclast activity involved in osteosarcoma. Further in vivo studies
are required to optimize the dosing regimen of nsPEF to fully study its
antitumor potential in the bone microenvironment.
Acknowledgments
All authors acknowledge Dr.Karl H. Shoenbach, Dr. Stephen
Beebe, and Mr. Frank Reidy from Old Dominion University for their kind
support.
Financial support
This research is supported by
National Natural Science Foundation of China (Nos. 81372425 and
81371658), National S & T Major Project (No. 2012ZX10002017),
Zhejiang Natural Science Foundation (LY13H180003), and Xinjiang
Cooperation Project (2014KL002).
Footnotes
Xudong Miao and Shengyong Yin contributed equally to this work.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
XM and SY carried out the molecular
genetic studies and drafted the manuscript. ZS carried out the
immunoassays. YZ participated in the design of the study and performed
the statistical analysis. XC conceived of the study, participated in its
design and coordination, and helped draft the manuscript. All authors
read and approved the final manuscript.
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Low Intensity and Frequency Pulsed Electromagnetic Fields Selectively Impair Breast Cancer Cell Viability
Sara Crocetti,1,2 Christian Beyer,3 Grit Schade,4 Marcel Egli,5 Jürg Fröhlich,3 and Alfredo Franco-Obregón2,6,*
Ilya Ulasov, Editor
1Department of Environmental Science, University of Siena, Siena, Italy
2Institute of Biomechanics, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
3Electromagnetic Fields and Microwave Electronics Laboratory, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
4Amphasys AG, Technopark Luzern, Root D4, Switzerland
5The
Center of Competence in Aerospace Biomedical Science and Technology,
Lucerne University of Applied Sciences and Arts, Hergiswil, Switzerland
6Department of Surgery, National University Hospital, Singapore, Singapore
University of Chicago, United States of America
* E-mail: hc.zhte.tseh@ocnarfCompeting Interests: One
of the authors, Grit Shade, is an employee of Amphasys, the company
that provided the authors with the prototype of the Impedance Flow
Cytometer utilized to conduct some of the experiments in the manuscript.
GS provided technical support only. There are no patents, products in
development or marketed products to declare. This does not alter the
authors’ adherence to all the PLOS ONE policies on sharing data and
materials.
Conceived
and designed the experiments: AFO JF SC. Performed the experiments: SC.
Analyzed the data: AFO SC. Contributed reagents/materials/analysis
tools: ME JF GS. Wrote the paper: AFO SC CB. Realized PEMFs device and
provided technical support: JF CB. Provided IFC instrument, technical
support and help with analysis and interpretation of the IFC results:
GS.
Received November 27, 2012; Accepted July 22, 2013.
Copyright notice
This
is an open-access article distributed under the terms of the Creative
Commons Attribution License, which permits unrestricted use,
distribution, and reproduction in any medium, provided the original
author and source are credited.
Introduction
There is a growing interest in the use of electromagnetic fields as an anticancer treatment [1]–[5].
The search for new therapeutic strategies is particularly active in the
field of oncology where standard antineoplastic treatments, based on
chemotherapeutic drugs and/or radiotherapy, possess potentially
detrimental secondary effects and on their own often fall short of
providing a complete and resilient recovery. Fueling this recent
interest is the fact that extremely low-frequency and low-intensity
pulsed electromagnetic fields (PEMFs) have been shown to be innocuous,
possibly even beneficial [4], [6]–[7],
to normal cell types. On the other hand, certain malignant cell classes
have been shown to be particularly vulnerable to their effects [5], [8]–[10].
A potential value of extremely low frequency PEMFs hence lies in their
use as an adjuvant treatment to more traditional chemo- and
radiotherapies with the aim of reducing their dosage, mitigating any
harmful secondary side effects and enhancing patient prognosis. Despite
recent successes, however, the types of signals applied and cancer
classes tested varied widely, producing a wide range of killing
efficiencies and succeeding in forestalling concurrence in this area of
research [1], [3]–[5].
A clear determination of the types of cancer most susceptible to PEMFs
and their subsequent optimization for targeted killing will be needed
before they can be used to selectively remove cancer cells from a
heterogeneous population of malignant and healthy cells.
Here we show
that the ability of ultra-low intensity and frequency PEMFs to
selectively kill breast cancer cells depends exquisitely on field
parameters. MCF-7 breast cancer cells are selectively vulnerable to
PEMFs within a discrete window of PEMF signal parameters and times of
exposure with resolutions of mTeslas and tens of minutes, respectively.
Using five independent means of monitoring cancer cell death we obtained
identical findings; selective killing of MCF7 cells was best achieved
with PEMFs of 3 mT peak-to-peak magnitude, at a pulse frequency of 20 Hz
and duration of exposure of only 60 minutes per day. By stark contrast,
this same pulsing paradigm (cytotoxic to MCF-7s) was innocuous to
normal MCF-10 breast cells. PEMF-based therapeutic strategies might thus
provide a manner to control certain classes of cancer while minimally
implicating healthy tissues.
Materials and Methods
Cell lines
Human
adenocarcinoma MCF7 cells and human not tumorigenic MCF10 cells were
provided by ATCC (Manassas, VA, USA). MCF7 cells were grown in D-MEM
(Life Technologies Corporation, Gibco, Paisley, United Kingdom)
supplemented with fetal calf serum (10%) (Life Technologies
Corporation,Gibco, Paisley, United Kingdom), L-glutamine (1%) (Life
Technologies Corporation, Gibco, Paisley, United Kingdom) and
penicillin-streptomycin (1%) (Sigma-Aldrich, St. Louis, MO, USA). MCF10
cells were cultured in D-MEM/F12 (Life Technologies Corporation, Gibco,
Paisley, United Kingdom) supplemented with fetal calf serum (5%) (Life
Technologies Corporation, Gibco, Paisley, United Kingdom), EGF (0.02%)
(Peprotech, NJ, USA), hydrocortisone (0.05%) (Sigma-Aldrich, St. Louis,
MO, USA), insulin (0.1%) (Sigma-Aldrich, St. Louis, MO, USA) and
penicillin-streptomycin (1%) (Sigma-Aldrich, St. Louis, MO, USA). The
cells were maintained at 37°C in a standard tissue culture incubator
(Vitaris AG, Baar, Switzerland) in an atmosphere of 95% humidity and 5%
CO2.
PEMFs exposure system
The PEMF exposure setup, described in Text S1 and illustrated in Figure S1 A-C,
was housed inside a standard cell culture incubator (Vitaris AG, Baar,
Switzerland) providing a humidified environment at 37°C, but lacking CO2
regulation. The cells were exposed to an asymmetric pulsed magnetic
field while continuously monitoring the field strength and temperature.
The non-exposed (control) cells were placed within the same incubator
for identical periods, but shielded from the magnetic fields by a mu
metal enclosure surrounding the coils. Thus, all cells were exposed to
the same climate and temperature.
PEMFs treatment
MCF7 and MCF10 cells were seeded in T25 flasks (SPL Life Sciences, Korea) at concentrations of 6.5×105cells/ml and 6.7×105
cells/ml, respectively. After 24 hours of being plated the cells were
washed with PBS (Life Technologies Corporation, Gibco, Paisley, United
Kingdom), given fresh medium and exposed to PEMFs for the first of three
daily trials; media was not changed from this point onward. An
asymmetric pulsed magnetic field of 6 ms interval at a repetition rate
of 20 and 50 Hz were applied at flux densities of 2.0, 3.0 and 5.0 mT
(peak-to-peak) for 1 hour/day for three days. Whereas exposure to PEMFs
at a repetition rate of 20 Hz caused a significant increase in cancer
cells death that was dependent on PEMF amplitude, PEMFs applied at a
repetition rate of 50 Hz did not produce any noticeable effects over
cell viability and were not dealt with further in this manuscript (Figure S2 A-B).
To test for effects of different exposure durations, cells were exposed
to PEMFs of 3 mT magnitude and at a repetition rate of 20 Hz for 30, 60
or 90 minutes per days for one, two or three days. Cells were collected
and analyzed on the first, second or third day for analysis, depending
on the assay being conducted.
Trypan blue assay
After
a given PEMF exposure protocol, cells were detached, spun down at 1200
rcf for 5 min, resuspended in 1 ml of PBS and incubated in trypan blue
at 11
(Sigma-Aldrich, St. Louis, MO, USA). A homogeneous suspension of cells
was then deposited into a Burker chamber (BRAND GMBH + CO KG, Wertheim
Germany), viewed microscopically and counted. The percentage of dead
cells was obtained by calculating the ratio of trypan blue positive
cells in treated and untreated samples. In some cases cells were allowed
to recover for up to 48 hours after their last PEMF exposure. These
cells were then detached, stained with trypan blue (Sigma-Aldrich, St.
Louis, MO, USA) and the number of dead cells calculated relative to
control.
Apoptosis determination by DNA strand break detection
Apoptosis
was measured by means of an Apo-direct kit (BD biosciences, Allschwil,
Switzerland) that labels DNA strand breaks using FITC-dUTP. After each
treatment 5×105cells
were collected and then fixed and stained accordingly to the
manufacturer’s instructions. The assay was run on a FACS Calibur (BD
Biosciences, Allschwil, Switzerland) flow cytometer using the positive
and negative controls provided in the kit as well as an additional
positive (death) control given by exposing MCF7 or MCF10 cells to 1 mM H2O2 overnight. H2O2 applied in this manner resulted in 87% ± 2% (+/– SD, n=4) and 82% ± 3% (+/– SD, n=4)
lethality in MCF7 and MCF10 cells, respectively. The FITC fluorescence
(520 nm) was detected in the FL1 channel and quantifies the amount of
DNA strand breaks. For each measurement, 20,000 cells were acquired and
analyzed by Flow Jo software (vers. 7.6.5) (Tree Star Inc. ON, USA).
Analysis of cellular electrical properties by means of Impedance microflow cytometer
Impedance
flow cytometry (IFC) was conducted on a prototype provided by Amphasys
AG (Root Längenbold (LU), Switzerland). Concisely, the apparatus
consists of a microfluidic chip, outfitted with a pair of
microelectrodes that measure changes of electrical impedance as cells
pass through dual interrogation points in response to an alternating
current at four user-defined frequencies in the mid frequency (MF) and
high frequency (HF) bands [11]–[15].
The obtained data (amplitude, phase and cell velocity) were
automatically converted into a standard FCS3 format and analyzed with
Flow Jo (vers. 7.6.5) (Tree Star Inc. ON, USA).
After treatment cells were collected, resuspended in PBS at a concentration of 4–5×106
cells/ml and pumped through the chip at a maximum velocity of 1 cm per
second, 500–1000 cells per second. For each measurement, 20,000 cells
were analyzed at a frequency of 0.5 MHz to monitor apoptosis [11]–[13], [15] or 9 MHz to determine metabolic status [11]–[14], [16]–[17].
Each sample was run in parallel with polystyrene beads (8 µm)
(Sigma-Aldrich, St. Louis, MO, USA) to obtain a standard signal response
over the entire frequency spectrum, establishing a set point.
Apoptosis determination by Annexin V staining
An
Annexin V/Propidium iodide (BD biosciences, Allschwil, Switzerland)
assay was used to monitor the progression of apoptosis at distinct
stages. Monitoring the dual staining pattern of Annexin V (FITC-
conjugated) and propidium iodide (PI) allowed for the identification of
early (Annexin V + and PI -) and late apoptosis as well as cells having
undergone necrosis (dead cells, Annexin V and PI +). After each
treatment, 3×105cells
were collected and stained as specified by the manufacturer’s
instructions. Staining was assayed on a FACS Calibur (BD Biosciences,
Allschwil, Switzerland), recording 20,000 cells for each measurement.
Fluorescence was detected in the FL1 and FL2 channels for FITC (Annexin
V) and PI, respectively. Data were acquired and analyzed by Flow Jo
software (vers. 7.6.5) (Tree Star Inc. ON, USA).
Statistical analyses
All histogram data were presented as mean ± SD (standard deviation) of at least 3 independent experimental runs (range=3
to 5) consisting of between 1 to 3 replicates for each biological
parameter analyzed. The exact number of measurements in each presented
data point is reported in the figure legend and is indicated in brackets
(n). Statistics were performed using the Wilcoxon Rank-Sum Test
(two-tailed) comparing each treated sample to relative control
(sham-exposed sample) for all the cell lines used. A p-value <0.05
was considered statistically significant (*) and a p-value < 0.005 was considered highly significant (**).
Results
PEMFs increase breast cancer cell death as detected by Trypan Blue inclusion
Our
objective was to devise a set of treatment protocols that could
potentially translate into the clinical arena to slow cancer growth,
while proving harmless to healthy tissues. We focused on a breast cancer
cell model given our previous success using PEMFs to slow their growth [8].
To ascertain the sensitivity of normal and cancer cells to PEMFs we
exposed MCF7 breast cancer cells and their normal breast epithelial
counterparts, MCF10s, to PEMFs of magnitudes between 2 mT and 5 mT and
at a repetition rate of 20 Hz for 1h per day for three days. Following
the last exposure (day 3) all samples were harvested and stained with
trypan blue to quantify cell death and compared to otherwise identically
treated control (non-exposed) cultures. A highly significant reduction
in the percentage of surviving MCF7 cells was observed in response to
exposure to 3 mT PEMFs. By contrast, exposure of identical MCF-7
cultures to PEMFs of either 2 mT or 5 mT amplitudes resulted in less
significant levels of cell death (Fig 1A).
On the other hand, exposure to 3 mT PEMFs, which proved the most
cytotoxic to MCF-7 cancer cells, was innocuous to “wild type” MCF10
cells (as were 2 and 5 mT PEMFs) and moreover, appeared to have even
accentuated their survival (mitigating resting levels of apoptosis)
relative to unexposed cells (also see Figure S5). We next sought to determine the best exposure interval to 3 mT PEMFs to kill breast cancer cells. Figure 1B
depicts cell death as a function of duration of exposure to 3 mT PEMFs
(20 Hz). Cells were exposed to 3 mT PEMFs for either 30, 60 or 90
minutes per day for 3 days before assaying for cell death. MCF7 cells
were most susceptible to PEMF exposures of 60 minutes duration, whereas
exposure times 50% shorter (30 minutes) or 50% longer (90 minutes) than
this resulted in significantly less amounts of cell killing (Fig 1B).
Once again, MCF10 cell viability was not compromised by PEMF exposure
of any duration. Indeed, PEMFs appeared to make MCF10 cells more
resistant to undergoing apoptosis, particularly in response to the
60-minute exposure regimen that proved most cytotoxic to MCF7 cells (Figure S5).
The data thus reveals a discrete set of PEMF parameters (magnitude,
frequency and duration of exposure) that are most cytotoxic to breast
cancer cells, whereas the identical set of PEMFs parameters were
apparently harmless to non-malignant cell types (also seeFigures S3 and S4).
Figure 1Trypan blue detection of dead cells after exposure to PEMFs for 3 consecutive days.
To ascertain
whether the PEMFs-induced cytotoxicity reported here is a cumulative
response or requires a threshold level of cellular insult to become
evident, we treated cells with 3 mT PEMFs for either 60 or 90 minutes
per day for 1, 2, or 3 days and next quantified the total number of dead
and living cells. Whereas in the unexposed cultures total cell number
steadily increased throughout the three days of trial, exposure to 60 or
90 minutes of PEMFs per day either totally abrogated or slowed the
increase in cell number, respectively (Fig 2).
On the other hand, the absolute number of dead (trypan blue positive)
cells did not scale down in proportion to the decrease in total cell
number as might be expected if cell proliferation was simply being
slowed, but instead, increased. Notably, on the third day, in response
to 60 minutes of daily exposure to PEMFs (3 mT), the total number of
cells in the culture decreased, whereas the total number of dead cells
increased, by –40% (+/–6% (SD); n=12) ((total cells in control sample – total cell in treated sample)/total cells in control sample)) and +20% (+/–13% (SD); n=12)
((dead cells in control sample – dead cell in treated sample)/dead
cells in control sample)), respectively, indicating heightened
cytotoxicity in response to PEMFs. Figure 3
shows that the increase in cell loss with time is greatest in cultures
treated for 60 minutes per day, rather than 90 minutes per day.
Figure 2Time course in the development of cell death in response to PEMF exposure.
Figure 3Box plots depicting the increase in cell death after 1, 2 or 3 days of consecutive PEMF treatment
Table 1Dead cells/total cells in MCF7 cells after 3 mT PEMFs treatment for 60 min/day for 3 days.
Table 2Dead cells/total cells in MCF7 cells after 3 mT PEMFs treatment for 90 min/day for 3 days.
Assessment of PEMF-induced apoptosis by detecting DNA strand breaks
Our Flow
Cytometric (FCM) determination of apoptosis was assayed with identical
PEMF parameters (days of consecutive exposure, durations of exposure,
field amplitudes and frequency) as those utilized for trypan blue
assessment of killing efficiency with identical results. Figure 4A
shows an overlay of MCF7 cells exposed to PEMFs of three distinct
intensities (2, 3 or 5 mT) for 60 minutes per day. A shift to the right
(greater FL1-H values) of a cell population reflects greater DNA damage.
As previously demonstrated, MCF7 cancer cells are particularly
vulnerable to 3 mT PEMFs. Figure 4B
shows the extent of 3 mT PEMF-induced DNA strand breaks following 30,
60 or 90 minutes exposures per day. Once again, 60 minutes of 3 mT PEMFs
for three consecutive days gave the greatest DNA damage in MCF7 cancer
cells. And, once again, stronger fields (5 mT) or longer exposures (90
minutes per day) were less cytotoxic to MCF7 cells (Fig 4A-D).
Further paralleling our trypan blue results, MCF10 normal breast
epithelial cells were not harmed by any of the PEMF paradigms tested,
particularly those observed to be especially cytotoxic to MCF7 cells.
Indeed, a slight protective effect (a leftward shift to lower FL1-H
values) was again discerned in MCF10 cells in response to the PEMF
parameters that were most cytotoxic to MCF7 breast cancer cells (Fig 4E; see also Figure S5).
To investigate if the previously described increase in DNA
fragmentation observed in MCF7 cells after 3 days of PEMF treatment was
cumulative with time, we stained cells after 1, 2 or 3 consecutive days
of exposure to either 60 or 90 minute of 3 mT PEMFs. Although
PEMF-induced DNA damage increased with time, it only really obtained
significance from control levels after the third day and was
particularly pronounced in response to 60-minute daily exposures (figure 5 A-D).
Our FCM analysis thus corroborates and strengthens our trypan blue
results, indicating that treatment with 3 mT PEMFs for 60 minutes per
day were most effective at killing MCF7 breast cancer cells while
leaving healthy cell classes (MCF10) unharmed.
Figure 4FCM determination of PEMF-induced DNA damage in MCF7 (cancer) and MCF10 (non-tumorigenic).
Figure 5Time course of apoptosis induction by PEMFs in MCF7 cells determined by FCM.
Determination of PEMF-induced apoptosis by Impedance Flow Cytometry
Impedance Flow Cytometry (IFC) assesses real-time cell viability by monitoring cellular electrical properties in behaving cells [11]–[13], [15].
In the dot plot generated from monitoring the entire cell population’s
electrical characteristics at a scan frequency of 0.5 MHz dead cells
reside in the far lower left quadrant (low impedance phase and magnitude
values). PEMFs produced a shift in MCF7 cells to the lower left
quadrant, particularly in response to 3 mT PEMFs, which gave the
greatest separation between living (right) and dying (left) cells (Fig 6A). Figure 6B
shows the results of MCF7 cells exposed to 3 mT PEMFs for either 30, 60
or 90 minutes per day for three days. In agreement with our previous
trypan blue and FCM assessment of apoptosis, cells exposed to 60 minutes
of 3 mT PEMFs per day exhibited the greatest percentage of dead cells
as detected by IFC (Fig 6 C-D).
In stark contrast, yet in further confirmation of our previous results,
MCF10 cells were slightly benefitted by these same PEMF parameters (Fig 6E, see also Figure S5).
Figure 6Post-PEMF apoptosis determination by impedance flow cytometry (IFC) at 0.5 MHz.
Assessment of cell metabolic status after PEMF treatment with IFC
At higher scan frequencies the IFC discerns metabolic status [11]–[14], [16].
At a scan frequency of 9 MHz the IFC detects two populations of cells,
the right-most population (higher phase values) reflects cells
experiencing the initial stages of metabolic stress [11]–[14], [16]–[17].
After three days of exposing MCF7 cells to PEMFs the magnitude of
right-most population augmented, the greatest right-shift coinciding
exactly with those parameters (3 mT, 20 Hz, for 60 min/day for 3 days)
producing the greatest cell death in response to PEMFs (Fig 7 A-D). And, once again, MCF10 normal breast cells were apparently benefitted by PEMFs as determined by IFC analysis at 9 MHz (Fig 7 D, see also Figure S5).
Due to the relatively broad scope of the phenotype (metabolic stress)
the effect is the largest we have measured in response to PEMFs (see
next, see also Figure S5).
Figure 7MCF7 and MCF10 cell metabolic status analyzed by IFC at 9 MHz.
To independently
validate that IFC effectively detects apoptosis and metabolic status in
our cell system we treated MCF7 cancer and MCF10 normal cells with 1 mM H2O2 to evoke cell death to an extent of 87% ± 2% (+/– SD, n=4) and 82% ± 3% (+/– SD, n=4), respectively. When analyzed by IFC at a scan frequency of 0.5 MHz cells treated with H2O2 were displaced to the far lower left quadrant (Fig 8A; cf Fig 6A-D).
Also, confirming that a cell population undergoing the initial stages
of metabolic stress is indeed shifted to the right (in IFC scans at 9
MHz) we obtained an analogous right-shift in MCF7 cells after overnight
exposure to 1 mM H2O2 (Fig 8B; cf Fig 7A-D). Hence, IFC does appear to be a viable method to monitor cancer cell viability.
Figure 8Independent corroboration that IFC detects impaired cells at 0.5 MHz and 9 MHz.
Assessment of PEMF-induced apoptosis by Annexin V staining
To further
corroborate our trypan blue, FCM and IFC data demonstrating the
induction of apoptosis in MCF7 cancer cells in response to PEMF
exposure, we performed Annexin V/PI assays, discriminating cells in
early apoptosis (Annexin V+/PI-) from dead and damaged cells (propidium
iodide +). MCF7 (cancer) and MCF10 (normal) cells were directly exposed
to the PEMFs paradigms we previously found to be most cytotoxic to MCF7
cells, 3 mT for 60 minutes per day. Figure 9A
shows that PEMF treatment resulted in a 13% increase in Annexin V+ MCF7
cells relative to control, quantitatively agreeing with our other
PEMF-induced cytotoxic assessments assayed with trypan blue (treated –
control: 11% dead cells), FCM (treated – control: 14% dead cells), IFC
at scan frequency of 0.5 MHz (treated – control: 16% dead cells) and IFC
at scan frequency of 9 MHz (treated – control: 25%). As previously
demonstrated with all the other apoptosis assays we performed, MCF10
cells were not adversely affected by these same PEMF parameters (Fig 9B) (also see Figure S5).
Figure 9Assessment of PEMF-induced apoptosis by Annexin V assay.
Discussion
Motivated by studies demonstrating the safety of very low frequency and intensity PEMFs [4], [6] and extending from our previous work [8],
demonstrating that MCF7 cancer cells are selectively vulnerable to 20
Hz pulsed electromagnetic fields, we investigated the effects of PEMFs
on human breast epithelial cells of malignant (MCF7) and non-malignant
(MCF10) phenotypes. Cytotoxic sensitivity to certain PEMFs parameters
was entirely restricted to the malignant phenotype and exhibited a clear
dependency on the duration, frequency and intensity of the PEMFs
employed. Specifically, breast cancer cells of the MCF7 lineage were
most vulnerable to PEMFs of 3 mT magnitude, at a repetition rate of 20
Hz and for an exposure interval of 60 minutes per day (Fig 1 A-C).
These same PEMF parameters, although cytotoxic to MCF7 cells, were
slightly protective to non-malignant breast epithelial cells of an
identical host lineage, MCF10 (see Figure S5).
For these experiments we limited our analysis to within three days of
exposure to remain within the realm of a clinically feasible therapeutic
strategy. Three days was also chosen as an appropriate end point to our
analysis as it avoided the overgrowth of control cells. In a tissue
culture paradigm such as ours, staying below cell confluence would
minimize the potential contributions of cell density/contact-induced
changes in biochemical status or nutrient deprivation to our measured
differences. The possibility hence remains, that increasing the number
of days of exposure to PEMFs may enhance the specificity and efficiency
of cancer cell killing. The design of longer time course experiments
will be the focus of our future studies. Nonetheless, our results,
although relatively modest are sufficiently provocative (in terms of
their reproducibility and selectivity) to merit future studies aimed at
further evolving this approach and yet, are consistent with previous
studies demonstrating that sensitivity to electromagnetic fields depends
on the signal parameters used as well as the type of cells exposed to
the fields [5], [7], [9], [18]–[19].
For this study we focused our attention on PEMF parameters that: 1) could practically translate into the clinical arena with reference to duration of exposure and 2)
were innocuous to healthy cell classes collaterally exposed to PEMFs
during clinical treatment. Our results are notable given that: 1)
our most effective exposure time to induce cancer cell (MCF7) death was
only one hour per exposure rather than 3–72 hours as previously
reported [5],[20]–[21] and; 2)
the field paradigms we designed were apparently innocuous to normal
cells (MCF10). As of yet, we have not achieved complete “selective”
killing with PEMFs. Although this objective might be achieved with
further fine-tuning of the PEMF parameters (exposure magnitude,
duration, signal shape, number of days of treatment) we cannot then
exclude the possibility that other tissues type might then be implicated
in the death pool. Quite notable, however, were the diametrically
opposed responses of MCF7 (cancer) and MCF10 (normal) cells to PEMFs,
widening the cytotoxic gap between exposed cancer and exposed normal
cells. Potentially, PEMFs might prove useful as a non-invasive adjuvant
treatment to be combined with other common anti-cancer therapies.
The selective killing of
cancer cells with PEMFs was corroborated by four independent
methodologies using five different analytical paradigms, covering the
full gambit of stages leading to ultimate cell death. Firstly, our
trypan blue results gave the number of cells in a late stage of cell
dying known as “postapoptotic necrosis” or “secondary necrosis” (Fig 1 A-B, 2 A-D and 3 A-B) [18], [22]–[23]. Secondly, our FCM analysis detected DNA breaks prior to cell death [17], [24] and occurring downstream of calcium-stimulated caspase activation (Fig 4 A-E and 5 A-D) [25].
Thirdly, we investigated the progression of apoptosis using Impedance
Flow Cytometry (IFC) that detects changes in the electrical properties
of cells reflecting physiological status [11]–[17], [24], [26]–[27] at two frequencies: 1) 0.5 MHz, to ascertain the number of cells having undergone apoptosis (Fig 6 A-E) [11]–[13], [15]and 2) 9 MHz, to monitor changes that coincide with the onset of cellular stress (Fig 7 A-E) [11]–[14], [16]–[17]. Several recent publications have supported the value of IFC to gauge cell viability [11]–[17], [27]. Finally, we employed an Annexin V/PI assay to distinguish early apoptotic cells from damaged or already dead cells (Fig 9 A-B) [28]–[29].
In all five assays of cell viability identical PEMF parameters produced
the greatest degree of cell damage to MCF-7 breast cancer cells, 3 mT
intensity for 60 minutes a day, demonstrating a clear and discrete
window of vulnerability of MCF7 cells to PEMFs of given characteristics.
Stronger fields, longer exposures, or higher frequencies to these
empirically determined values (3 mT, 20 Hz, 60 minutes exposures per
day) were less cytotoxic to MCF7 cells, clearly demonstrating the
importance of field optimization for the eventual killing of malignant
cell classes with PEMFs.
A clear window of vulnerability of cancer cells to PEMFs exists; more is not necessarily better.
That weaker fields, or less exposure to them, are less lethal, upon
first impression, might seem somewhat intuitive. However, the fact that
stronger, or longer, exposure to fields is less efficient at killing,
implies some specifically of biological action, rather than a
straightforward dose-dependent accumulation of generalized damage over a
susceptible cell status. The validity of the described window effect is
implicitly substantiated within the context of our data presented
herein, the fact that five independent assays (four distinct
methodologies) of measuring cell viability gave the identical result and
produced similar magnitudes of cell death (also see Figure S5).
The cytotoxic-dependency on exposure duration was so robust that it was
also apparent when examining the time course in the development of
cytotoxicity during three days of consecutive PEMF exposure. That is,
60-minute daily exposures to PEMFs gave greater ratios of cell death (figure 3) and greater amounts of DNA fragmentation (figure 5)
than 90 minutes of daily exposure. Moreover, the PEMF parameters that
were most cytotoxic to MCF7 breast cancer cells proved most beneficial
to MCF10 normal breast cells. Similar window effects have been reported
in the field of electromagnetics and have been openly discussed in the
literature, yet there are no accepted models to explain their existence [19], [30]–[31]. Within the Protection Guidelines Report of the International Commission on Non-Ionizing Radiation [30]
it is stated, “Interpretation of several observed biological effects of
AM (amplitude modulated) electromagnetic fields is further complicated
by the apparent existence of “windows” of response in both the power
density and frequency domains. There are no accepted models that
adequately explain this phenomenon, which challenges the traditional
concept of a monotonic relationship between the field intensity and the
severity of the resulting biological effects.”
At this juncture, however,
the relative contributions of an actual slowing of cell proliferation
and the induction of cell death to the overall effect of PEMFs is
unclear (cf figure 2),
as is the rate and extent of absorption of dead cells by the culture
after their demise. Therefore, although cell cycle withdrawal possibly
resulting from PEMFs may contribute to observations reported here, the
most directly measurable effect is that of induced apoptosis.
Nonetheless, the capacity of PEMFs to slow the proliferation of a cancer
cell class also would be positive clinical outcome and of relevance in
advancing PEMF-based anti-cancer therapies.
The molecular mechanisms
whereby cancerous (MCF7) cells are compromised yet, healthy (MCF10)
cells are not fully understood and yet, of utmost importance for the
ultimate development of PEMF-based strategies to combat cancer and will
be the focus of our future investigations. We speculate that the window
effect observed in this study results from changes in intracellular
calcium handling in response to PEMF exposure. Calcium signaling is
renowned for its multimodal effects relying on intracellular calcium
increments that: 1) result
from both calcium influx across the cell surface membrane and release
from intracellular membrane-delimited compartments; 2) are simultaneously coded in space, time and holding level; 3) exhibit negative- and positive-feedback regulatory mechanisms and; 4) are coordinated by dynamic changes in membrane organization [32]–[33]. As a commonly reported consequence of PEMF exposure is elevations of intracellular calcium level [34]
one possibility is that PEMFs mediate their effects via influencing
intracellular calcium signaling pathways. In the context of this report 3
mT PEMFs at a frequency of 20 Hz for 60 minutes per day would create
the “correct” combination of calcium signals that would most effectively
result in cell death. Indeed, it has been previously shown that
chelating or augmenting intracellular calcium accordingly spares or
compromises MCF7 survival, respectively [35]–[37]. The shift to the right observed at 9 MHz in IFC (Fig 4 A-D) likely reflects changes in membrane complexity and cytoplasmic reorganization (change in whole-cell capacitance) [11]–[14], [16]–[17]
that coincide with the establishment of cytomorphological features that
reflect the modulation of biochemical pathways that, in turn, regulate
the delicate balance between cell proliferation and apoptosis including,
modifications in mitochondrial metabolism downstream of changes in
intracellular calcium levels [16]–[17], [33], [38]. Future studies of ours will focus on the effects of PEMFs over cytosolic calcium increments.
Non-malignant
MCF10 cells were unaffected, or even fortified, by the PEMF paradigms
producing the greatest damage in MCF7 cells, revealing another level of
specificity of action and supporting the possibility that it may be
ultimately feasible to selectively remove cancer cells from an organism
without implicating normal tissues in the death pool using PEMF-based
technologies (Figs 1 A-B, ?,4E,4E, ?,6E,6E, ?,7E,7E, ?,9B9B
and ). The immunity of MCF10 cells to PEMFs might suggest that their
endogenous calcium homeostatic mechanisms are capable of buffering, or
even exploiting, small increments in intracellular calcium
concentrations, whereas MCF7 cells are not able to withstand even modest
perturbations in cytosolic calcium levels, a supposition that is
supported by recently published studies[36]–[37].
In further support for such a calcium-dependent mechanism of
preferential killing of malignant cells it has been shown that
Panaxydol, a derivative of Panax ginseng that induces sustained
elevations in cytosolic calcium, preferentially induces apoptosis in
cancer cells (including MCF7s) but not normal cells [39].
Such a selective calcium-dependent mechanism of cancer cell killings
may eventually help in the refining of PEMF-based technologies to better
execute the preferential killing of breast cancer cells in clinical
settings.
Consistent diametrically
opposed responses of non-tumorigenic MCF10 and cancer MCF7 cells to PEMF
treatment observed across 5 different assays of cell viability.
Observed range of sample
responses in MCF7 cancer cells after exposure to the PEMF parameters
producing the greatest cytotoxicity (3mT, 20 Hz, 60 minutes per day for
three days).
We would like to acknowledge
Dr Malgorzata Kisielow and Ms Anette Schütz of the Flow Cytometry
Laboratory of the ETH and University of Zürich for expert technical
assistance during the FCM acquisition and analysis. Finally, we would
like to thank the Statistical Consulting group of the ETH for their
assistance in elaborating our statistical analysis.
Funding Statement
This study was partially supported by the Swiss Federal Office of Public Health (http://www.bag.admin.ch/)
under the mandate number 11.003272, “Effects of pulsed electromagnetic
fields on the proliferation of different mechano-sensitive cell types”.
The funders had no role in study design, data collection and analysis,
decision to publish, or preparation of the manuscript. No additional
external funding received for this study.
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Technol Cancer Res Treat. 2012 Feb;11(1):83-93.
Long term survival of mice with hepatocellular carcinoma after pulse power ablation with nanosecond pulsed electric fields.
Frank Reidy Research Center for Bioelectrics, Old Dominion
University, Norfolk Virginia, 4211 Monarch Way, Norfolk, Virginia 23508,
USA.
Abstract
Novel therapies are needed for treating hepatocellular carcinoma
(HCC) without recurrence in a single procedure. In this work we
evaluated anti-neoplastic effects of a pulse power ablation (PPA) with
nanosecond pulsed electric fields (nsPEFs), a non-thermal, non-drug,
local, regional method and investigated its molecular mechanisms for
hepatocellular carcinoma tumor ablation in vivo. An ectopic tumor model
was established using C57BL/6 mice with Hepa1-6 hepatocellular carcinoma
cells. Pulses with durations of 30 or 100 ns and fast rise times were
delivered by a needle or ring electrode with different electric field
strengths (33, 50 and 68 kV/cm), and 900 pulses in three treatment
sessions (300 pulses each session) or a single 900 pulse treatment.
Treated and control tumor volumes were monitored by ultrasound and
apoptosis and angiogenesis markers were evaluated by
immunohistochemistry. Seventy five percent of primary hepatocellular
carcinoma tumors were eradicated with 900 hundred pulses at 100 ns
pulses at 68 kV/cm in a single treatment or in three treatment sessions
without recurrence within 9 months. Using quantitative analysis, tumors
in treated animals showed nsPEF-mediated nuclear condensation (3 h
post-pulse), cell shrinkage (1 h), increases in active executioner
caspases (caspase-3 > -7 > -6) and terminal deoxynucleotidyl
transferase dUTP nick-end-labeling (1 h) with decreases in vascular
endothelial growth factor expression (7d) and micro-vessel density
(14d). NsPEF ablation eliminated hepatocellular carcinoma tumors by
targeting two therapeutic sites, apoptosis induction and inhibition of
angiogenesis, both important cancer hallmarks. These data indicate that
PPA with nsPEFs is not limited to treating skin cancers and provide a
rationale for continuing to investigate pulse power ablation for
hepatocellular carcinoma using other models in pre-clinical applications
and ultimately in clinical trials. Based on present treatments for
specific HCC stages, it is anticipated that nsPEFs could be substituted
for or used in combination with ablation therapies using heat, cold or
chemicals.
Acc Chem Res. 2012 Apr 30. [Epub ahead of print]
Detecting and Destroying Cancer Cells in More than One Way with
Noble Metals and Different Confinement Properties on the Nanoscale.
Dreaden EC, El-Sayed MA.
Source
Laser Dynamics Laboratory, Department of Chemistry and Biochemistry,
Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United
States.
Abstract
Today, 1 in 2 males and 1 in 3 females in the United States will
develop cancer at some point during their lifetimes, and 1 in 4 males
and 1 in 5 females in the United States will die from the disease. New
methods for detection and treatment have dramatically improved cancer
care in the United States. However, as improved detection and increasing
exposure to carcinogens has led to higher rates of cancer incidence,
clinicians and researchers have not balanced that increase with a
similar decrease in cancer mortality rates. This mismatch highlights a
clear and urgent need for increasingly potent and selective methods with
which to detect and treat cancers at their earliest stages.
Nanotechnology, the use of materials with structural features ranging
from 1 to 100 nm in size, has dramatically altered the design, use, and
delivery of cancer diagnostic and therapeutic agents. The unique and
newly discovered properties of these structures can enhance the
specificities with which biomedical agents are delivered, complementing
their efficacy or diminishing unintended side effects. Gold (and silver)
nanotechnologies afford a particularly unique set of physiological and
optical properties which can be leveraged in applications ranging from
in vitro/vivo therapeutics and drug delivery to imaging and diagnostics,
surgical guidance, and treatment monitoring. Nanoscale diagnostic and
therapeutic agents have been in use since the development of micellar
nanocarriers and polymer-drug nanoconjugates in the mid-1950s, liposomes
by Bangham and Watkins in the mid-1960s, and the introduction of
polymeric nanoparticles by Langer and Folkman in 1976. Since then,
nanoscale constructs such as dendrimers, protein nanoconjugates, and
inorganic nanoparticles have been developed for the systemic delivery of
agents to specific disease sites. Today, more than 20 FDA-approved
diagnostic or therapeutic nanotechnologies are in clinical use with
roughly 250 others in clinical development. The global market for
nano-enabled medical technologies is expected to grow to $70-160 billion
by 2015, rivaling the current market share of biologics worldwide. In
this Account, we explore the emerging applications of noble metal
nanotechnologies in cancer diagnostics and therapeutics carried out by
our group and by others. Many of the novel biomedical properties
associated with gold and silver nanoparticles arise from confinement
effects: (i) the confinement of photons within the particle which can
lead to dramatic electromagnetic scattering and absorption (useful in
sensing and heating applications, respectively); (ii) the confinement of
molecules around the nanoparticle (useful in drug delivery); and (iii)
the cellular/subcellular confinement of particles within malignant cells
(such as selective, nuclear-targeted cytotoxic DNA damage by gold
nanoparticles). We then describe how these confinement effects relate to
specific aspects of diagnosis and treatment such as (i) laser
photothermal therapy, optical scattering microscopy, and spectroscopic
detection, (ii) drug targeting and delivery, and (iii) the ability of
these structures to act as intrinsic therapeutic agents which can
selectively perturb/inhibit cellular functions such as division. We
intend to provide the reader with a unique physical and chemical
perspective on both the design and application of these technologies in
cancer diagnostics and therapeutics. We also suggest a framework for
approaching future research in the field.
Biomed Eng Online. 2010; 9: 13.
Published online 2010 Feb 26. doi: [10.1186/1475-925X-9-13]
PMCID: PMC2839970
PMID: 20187951
A statistical model for multidimensional irreversible electroporation cell death in tissue
2
Author information Article notes Copyright and License information Disclaimer
1Center for
Bioengineering in the Service of Humanity and Society, School of
Computer Science and Engineering, Hebrew University of Jerusalem, Givat
Ram, Jerusalem 91904, Israel
2Department of
Mechanical Engineering, Graduate Program in Biophysics, University of
California at Berkeley, Berkeley CA 84720, USA
Irreversible electroporation (IRE)
is a minimally invasive tissue ablation technique which utilizes
electric pulses delivered by electrodes to a targeted area of tissue to
produce high amplitude electric fields, thus inducing irreversible
damage to the cell membrane lipid bilayer. An important application of
this technique is for cancer tissue ablation. Mathematical modelling is
considered important in IRE treatment planning. In the past, IRE
mathematical modelling used a deterministic single value for the
amplitude of the electric field required for causing cell death.
However, tissue, particularly cancerous tissue, is comprised of a
population of different cells of different sizes and orientations, which
in conventional IRE are exposed to complex electric fields; therefore,
using a deterministic single value is overly simplistic.
Methods
We introduce and describe a new
methodology for evaluating IRE induced cell death in tissue. Our
approach employs a statistical Peleg-Fermi model to correlate
probability of cell death in heterogeneous tissue to the parameters of
electroporation pulses such as the number of pulses, electric field
amplitude and pulse length. For treatment planning, the Peleg-Fermi
model is combined with a numerical solution of the multidimensional
electric field equation cast in a dimensionless form. This is the first
time in which this concept is used for evaluating IRE cell death in
multidimensional situations.
Results
We illustrate the methodology using
data reported in literature for prostate cancer cell death by IRE. We
show how to fit this data to a Fermi function in order to calculate the
critical statistic parameters. To illustrate the use of the methodology,
we simulated 2-D irreversible electroporation protocols and produced
2-D maps of the statistical distribution of cell death in the treated
region. These plots were compared to plots produced using a
deterministic model of cell death by IRE and the differences were noted.
Conclusions
In this work we introduce a new
methodology for evaluation of tissue ablation by IRE using statistical
models of cell death. We believe that the use of a statistical model
rather than a deterministic model for IRE cell death will improve the
accuracy of treatment planning for cancer treatment with IRE.
Background
Electroporation is the physical
phenomenon in which the cell membrane becomes permeabilized when certain
electric fields are applied across the cell [1].
When cell membrane permeability increase is only temporary and the
resealing happens in the next step, reversible electroporation has
occurred [2–8]. Reversible electroporation has important applications in chemical treatment of tissues for drug delivery and gene therapy [9–11]
If permeability increase is sufficiently long to disrupt intracellular
homeostasis, irreversible electroporation has occurred and as a
consequence the cell dies [12].
Until recently, the main practical application of irreversible
electroporation was microbial inactivation in the food industry [13–15].
A summary of much of the current information on the use of IRE in the
food industry can be found in a recent book on this topic [15]. The use of irreversible electroporation in a non thermal mode for tissue ablation in the body in vivo is a new minimally invasive molecular selective surgical technique [16–21].
Tissue electroporation utilizes electrodes brought into contact with
tissues in the body to deliver electric pulses, which in turn induce
electroporation in a desired volume of tissue [22,23].
Non-thermal irreversible electroporation (NTIRE) is electroporation
delivered in such a way that the Joule heating induced temperature
elevation in tissue only reaches levels that are not harmful[24].
Therefore, only the cell membrane in the treated area is affected while
other molecular structures in the tissue are spared, effectively making
NTIRE molecular surgery[23,25]. One application of NTIRE is the treatment of cancerous tumors [16,17,20,23].
In a typical procedure, electrodes are inserted around the tumor and
pulses of specific amplitude and frequency are applied in the hope that
they will affect the entire area of the tumor and cause complete cell
death [16,17,20,23].
Treatment planning is important for NTIRE treatment success. In the
past, mathematical studies on electroporation in tissue used a
deterministic model to evaluate the electroporation events, i.e. it was
assumed that the event of electroporation is associated with a single
value of local electric field current and heat distribution during pulse
application[17,21,24–33]. Particular attention was paid to the electrode confirmation optimization [34,35] and the impact of tissue histology [36].
Nevertheless, assuming a deterministic effect of electroporation
parameters is correct only when the cell population is homogeneous and
uniform. In malignant tissues the cell population is at different stages
of development and is therefore not homogeneous. It has been known in
the field of irreversible electroporation since the 1960’s that in a
population of aging cells there is a statistical distribution which
correlates cell survival to electroporation parameters [37,38].
The outcome of the application of electric pulses across cells depends
on many parameters. These include field amplitude, polarity, number of
electric pulses, shape of pulses, length of pulse, interval between
pulses, and environmental temperature. Particularly relevant to tissue
are the additional parameters of cell type, morphology, age and size [2–8,26,37,38].
All these parameters determine if the cell membrane will undergo
reversible electroporation, irreversible electroporation or no
electroporation at all. When treating cancer cells with NITRE, it is
obviously important to deliver the electric pulses such that the
electric conditions that destroy cells are achieved throughout the
entire volume of targeted undesirable tissue. The use of NTIRE for
tissue ablation is complicated by the fact that the electric fields
which occur in the treated tissue are complex and vary in space as a
function of distance from the electrodes, tumor and electrode geometry
e.g [17,25].
Therefore, there is evident need for a mathematical methodology of
treatment planning which will ensure that the entire volume of
undesirable tissue undergoes electric conditions that destroy all the
cells.
The food industry, from which some of the first fundamental studies on IRE emerged [37,38]
has long recognized that electroporation is a statistical event in a
heterogeneous population of cells. In food processing, it is important
to completely destroy undesirable cells; as is in treatment of cancer.
Therefore, statistical models of cell destruction by irreversible
electroporation have been developed in the food industry for processing
planning. Our goal in this study is to show how these models can be used
in treatment planning for ablation of cancer cells in tissue.
The first mathematical models to describe pulsed electric
field induced cell death employed a first order inactivation kinetics
model and are given in equation (1), [39]
(1)
Where S is the survival ratio, k is the kinetic constant which depends of pulse strength and t is the total treatment time.
However, experimental studies show that cell death by
pulsed electric fields depends on more parameters than those included in
a first order kinetic model. Hülsheger and Niemann proposed a model
which is different from first order inactivated models and incorporates
more of the relevant pulsed electric field parameters, Equation (2), [40]:
(2)
Where be is a regression constant, which is bacteria and medium type dependent. E is the applied field and Ec is a cell size and pulse length dependent parameter, obtained by extrapolation to 100% survivals. Further model development [14,41,42]
have lead to the model in Equation 3, which also includes brings the
pulse length as a critical parameter in electric pulse field induced
cell death:
(3)
Where tc and Ec are microorganism and medium type dependent, E is the applied field and t is the treatment time.
Additional models were developed which take into account
the fact that the treated microorganisms population is not homogeneous,
hence each individual cell has its own resistance to the applied
treatment. Assuming a natural distribution among cells, the survival
curve can be described by a distribution function[43–45].
Peleg [46]proposed an inactivation model, Equation 4, based on Fermi function:
(4)
Where, Ec(n) is the field at which 50% of a population of cells are dead and A(n) are function of the number of pulses, n.
Recently, a Weibull distribution, function has been shown
to describe effectively several microbial inactivation curves, Equation
5, [44,45]:
(5)
Where n(E) and b(E) are constants and depend on microbial
and media type and treatment parameters (electric field and treatment
time).
Several additional models have been reported in the literature [47–49]. San Martin et al [50] and Alvarez et al [51] made a comparison study of several proposed statistical models.
The statistical mathematical models used in the food
industry deal with one dimensional electric field. These models have
practical value in the food industry because the majority of the
geometrical configurations in which IRE is used in that industry are
one-dimensional. However, when irreversible electroporation is used for
medical treatment the electric fields that develop in the treated tissue
they are seldom one dimensional[17].
In developing NTIRE mathematical models for medicine it would be
beneficial to have a methodology that could predict the outcome of a
particular electroporation treatment in tissues made of a variety of
cells that experience multidimensional and complex electric fields at
complex electroporation protocols.
The goal of this study is to introduce such a methodology,
which will lead to the treatment planning according to parameters we
previously discussed. Specifically, we suggest combining a mathematical
model that calculates the multidimensional electric field in tissue with
a statistical and empirical model that predicts cellular damage as a
function of the local and temporal values of electric fields and the
electroporation protocols. Mathematical models that calculate the
multi-dimensional electric fields which occur during tissue
electroporation through the solution of the electric field equation have
been used successfully in the past for electroporation analysis and
research [22,52] as well as for treatment planning in NTIRE [17,20,53].
In the past these mathematical models of electric fields were combined
with a deterministic single valued evaluation of the electric field that
affects cell viability and the results were expressed as a demarcation
line which separates between cells that were electroporated and those
that are not. There has been no methodology introduced, up to our
knowledge, which evaluates the statistical distribution of
electroporated cells. Here we propose a second step after the electric
field calculations which consists of inserting the calculated local
value of the electric fields into a statistical empirical model of the
type derived in the food industry for estimate of local cell damage.
This analysis should produce a map of tissue damage in the treated
region for a certain electroporation protocol which is the goal of
treatment planning. We anticipated that the major difference in the
outcome of the analysis between the methodologies proposed in this study
and the mathematical methodology used in the past is the occurrence of a
domain in which there will be a transition between electroporated and
non-electroporated tissue, rather than a discrete demarcation line.
Knowing this transition zone is obviously important in treatment of
cancer.
This study describes this mathematical
model of electroporation in tissue. Since we want to introduce a general
methodology, we will employ dimensionless analysis – which is basic in
fundamental engineering analysis. To illustrate the method we will use a
Peleg-Fermi type statistical model [46].
Because there is no good experimental data in the literature for IRE in
tissue and to nevertheless focus ideas we use and extrapolate limited
experimental data obtained for DU 145 prostate cancer cells in a
previously published work, based on in vivo experiments, by Canatella et al[54]. The experimental parameters in this specific study. which included field strength from 0.1 to 3.3 kV/cm, pulse length 50 ?sec -20 ms, number of pulses 1-10 [41], fall to the range of parameters used in vivo studies for the successful irreversible electroporation [16,20,22,53];
therefore, we applied these results for demonstration in the current 2D
treatment planning model application. In the investigated
electroporation study the pulse lengths were significantly longer than
the cell membrane charging time which is about 1 ?sec [55]
and thus a steady state DC analyses can be implemented. Obviously, for
this method to become practical much experimental research is needed to
obtain statistical data for cells in tissue.
Methods
To develop the methodology we will
employ a statistical empirical model of cell damage by electroporation
based on the Peleg-Fermi formulation[46].
The reason for choosing this model over others is related to recent
findings in the field of tissue NTIRE. These findings show that the
number of pulses is an important treatment parameter[16,26,56].
We chose to use the Peleg-Fermi model since it directly incorporates
the dependence of cell death on pulse number and field strength for the
given pulse length. Other models, for instance, Weibull function
parameters do not incorporate directly the pulse number and pulse length
as basic parameters and include only the effect of field amplitude and
total treatment time. Obviously the other models can be also used and it
is quite likely that new statistical models will be developed in the
future for treatment of tissue; however, this study should be viewed
primarily as a first attempt at introducing statistical modeling in the
analysis of tissue electroporation.
Peleg [46] depicts the dependence of the survival ratio S (S = N/No or the ratio of living cell count after IRE treatment (N) and before IRE treatment (No)) on the electric field that cells experience, E [V/m] and number of pulses, n, for various electroporation protocols.
The model is based on the Fermi equation of the form described in Equation 4.
The equation incorporates Ec(n) whose typical behavior is
(6)
Where Eco is the intersect of the curve with the y-axis
and is cell type and pulse type specific, n, is the number of pulses and
k1 is cell type and pulse type specific. The pulse type specificity
relates to all the other parameters of electroporation that are not
included explicitly in the equation (i.e. shape of pulse, length of
pulse, interval between pulses).
The equation for A(n), whose typical behavior is,
(7)
The electric field during the electroporative pulses application is obtained from the solution of the Equation 8,
(8)
where, ? [S] is the local conductivity and ?[V] is the local potential
To determine the electric potential in the analyzed region
Equation (8) is solved subject to the electroporation boundary
condition which are:
(9)
where ?1, ?2 are the geometrical locations of the electroporation electrode boundaries.
Boundary conditions that do not relate to the electrodes
are handled in a standard way, as insulating boundaries. A typical
example will be shown later in the results section.
Since we introduce here a general methodology we will
employ dimensionless analysis, as commonly done in engineering analysis.
We assume that the typical dimension of this problem is the distance L
[m]
, between the centers of gravity of the two electroporation
electrodes. We will non-dimensionalize space variables with respect to
the dimension, L, and electric field quantities with respect to Eco
which is a typical quantity with units of electric field and dependent
on the tissue type and electroporation protocol. Specifically:
(11)
The dimensionless form of Equations (4) and (6-11) becomes,
(12)
We anticipate that mathematical modeling
of IRE will be performed the following way. The experimental data,
gathered in preliminary experiments with tissues, will be cast in a
statistical model of cell death as a function of various electroporation
parameters rather than a deterministic model. It is quite possible that
the experimental studies will reveal other parameters of importance for
the statistical model; for instance, the effect of the variable
polarity, anisotropic properties in relation to the electric fields,
heterogeneity to mention a few. From the data gathered in the food
industry we have little doubt that in tissue the cell electroporation as
a function of electroporation parameters will have a statistical
distribution rather than be deterministic. Then the Laplace equation is
solved for the particular geometry and electroporation protocol and the
statistical model can be used as a survival look-up table with the
calculated local electric field to determine the transition region to
complete cell death. It should be emphasized that in other tissue
ablation techniques such as cryosurgery and thermal ablation this
statistically affected transition region has become an important
consideration in treatment planning.
Results and Discussion
The goal of this part of the study is to
illustrate the methodology with an example. Since there is no
experimental statistical data available for tissues we decided to
illustrate the concept using some limited data available from
experiments with prostate DU 145 cancer cells in the work by Canatella
et al[54],
which we extrapolate. The goal of this study was to introduce the idea
that electroporation effects on tissue should be analyzed as a
statistical, probabilistic event rather than as a deterministic event.
Tissues are obviously heterogeneous at the microscopic and macroscopic
scale and often anisotropic. Others and we have published, studies on
the effects of tissue heterogeneity on tissue electroporation and it is
substantial [27,30,36,57–60].
However, in order to single out the effect of a statistical
distribution of electroporation events on the outcome of
electroporation, we chose to model the tissue as homogeneous. This
approach to the analysis of a newly examined phenomenon is obviously
quite standard [22,33].
We could have used data from experiments with
micro-organisms from the food industry or just simple parametric
studies; however, we thought that although limited, the prostate cancer
cell data is somewhat more relevant. Obviously future experimental
studies on tissues are needed in this field.
The data of Canatella et al [54]gives the percentage cell survival as a function of applied field intensity for 1, 2, 4 and 10 pulses with pulse lengths of 50 ?sec, 100 ?sec, 1 msec and 10 msec.
We have curve fitted the data of Canatella et al. [54] to the Fermi type model of Peleg, Equation 1 [46], The curve fitted parameters Ec and A as a function of n were calculated from the experimental data and are shown in Figures ?Figures1A1A to ?to1D1D.
Dependence of Ec and A on the number of pulses as developed from the work of Canatella et al [54]. A. 50 ?sec pulse lenth. B.100 ?sec pulse length, C. 1 msec pulse length and D. 10 msec pulse length.
From the plots in Figures ?Figures1A1A to ?to1D1D we extrapolated to n = 0 to obtain the values of Eco and Ao for each electroporation protocol. The plots in Figures ?Figures1A1A to ?to1D1D were
non-dimensionalized as in Equations 16 and 17 and further extrapolated
to larger number of pulses than in the experiments of Canatlela et al[54]. These dimensionless representations are shown in Figures (2A, B, C and ?and2D).2D). It should be obvious that what we show is a general methodology and the particular use of the Canatella et al[54] data is to have some basis grounded on experimentation for the description of the methodology.
Dependance of Ec and A on the number of applied pulses, normalized to Eco. A. 50 ?sec pulse lenth. B.100 ?sec pulse length, C. 1 msec pulse length and D. 10 msec pulse length.
We will further illustrate the methodology by analyzing a
configuration that is typical to the NTIRE experiments described
previously[61].
Specifically, in those experiments two long 1 mm diameter cylindrical
electrodes are placed at a separation of 1 cm between them in a parallel
configuration. This situation is primarily two dimensional. For
simplicity we will assume that the tissue is isotropic (although the
method is obviously not restricted to these conditions) with ? = 0.42 S/m[62].
The electric field equation is solved using the finite
element method with Comsol Multiphysics (version 3.4). The paradigm of
the analysis is as follows. The field equation is solved for prescribed
voltage boundary conditions on the electrodes and insulating boundary
conditions on the outer edges of the domain, and then the curves in
Figure ?Figure22 are
used to evaluate the cell survival for each value of the local field
and the appropriate number of pulses and electroporation protocols. In a
typical parametric treatment study we have varied the C values
(dimensionless voltage on the electrodes) and treatment parameters
(number of pulses and length of pulses) and plotted from the electric
field data a spatial depiction of the cell survival. The calculated
dimensionless field distribution in the tissue is given in Figures 3(A-C) The cell survival 2D plots are shown in Figures 4(A-H).
Viability plots for IRE in prostate tissue in 2D
for different electroporation protocols that have various number of
pulses (n), voltages on the electrodes C, and pulse length, (t). A. n = 10 C = 1.5 t = 100 ?sec B. n = 50 C = 1.5 t = 100 ?sec C. n = 100 C = 1.5 t = 100 ?sec. D. n = 50 pulses, C = 0.5, t = 100 ?sec E. n = 50 pulses c = 1.5 t = 100 ?sec F. n = 50 pulses c = 2.5 t = 100 ?sec. G. n = 50 C = 1.5 t = 100 ?sec H. n = 50 C = 1.5 t = 1 msec.
Figures 4(A-H) show
the distribution of cells which survive IRE in relation to the location
of the electroporation electrodes for various electroporation
protocols. The depiction of the cell damage is obtained from the
calculation of the electric fields and the use of the Peleg-Fermi type
empirical data. The most important aspect of our findings is that around
the treated tissue there is a rim of tissue in which the NTIRE caused
damage is partial. The existence and the extent of regions in which only
part of the cells are ablated cannot be determined from the
deterministic cell death models which have been used before The shape of
the treated region is obviously a function of the electrical parameters
and the geometry of the probes. From the results it is evident that the
damaged region increases as a function of applied voltage, pulse number
and pulse length. Both regions of the sub-lethal injured and totally
inactivated cells are changing as a function of the applied protocol.
The general pattern is interesting: larger numbers of pulses increase
the region in which there is complete cell death (blue color) while
large field amplitude and longer pulse length increase both the region
in which there is complete cell death as well as the transition region
of partial cell injury (Figures 4(A-C)).
These findings further illustrate the importance of using a statistical
distribution model for a precise analysis of the effects of NTIRE. The
geometrical form of the treated area changes its shape with the
treatment parameters in a form similar to that observed in other studies
[33].
In this study we introduce a methodology for evaluating
cell death in a volume of tissue treated by IRE using a statistical cell
death model rather than the deterministic model for cell death used in
the past.
The examples shown in this study illustrate the
methodology for mathematical analysis of IRE for multidimensional
electroporation protocols from fundamental information on the empirical,
statistical relation between cell survival and electroporation
protocols in experiments and mathematical solution of the field
equation. For a desired region of tissue ablation it is possible to
employ this methodology for choosing the desirable electric pulse
protocol in terms of pulse amplitude, length, number of pulses and
intervals between the pulses. Because non-thermal irreversible
electroporation also requires pulses that do not produce thermal damage
future studies may also require solving this model of electric fields
together with thermal models dealing with temperature distributions as
well as thermal damage. While shown for irreversible electroporation
this mode of analysis could be employed in a similar form with
experimental curves for reversible electroporation. Obviously this is a
theoretical study whose goal it is to propose a statistical model for
IRE mathematical modeling. It should be empathized that the data used in
this work is for illustration purposes only and real curves and
parameters should be developed for each specific case. We performed the
simulations based on two assumptions. First, we extrapolated data from
in vitro experiment performed by Canatella et al. [54]
to an in vivo situation in tissue, second we used the Peleg-Fermi model
to extrapolate the effect of electric field delivered at a much larger
number of pulses than was reported by Canatella et al. [54].
Eventually, in order to use the theoretical methodology introduced in
this work in clinical applications experimental studies need to be
performed to develop real values for statistical analysis.
The results that were obtained show that
when a statistical model is used to predict cell destruction by IRE
there is a transition zone between complete cell destruction and
complete cell survival. In contrast, previous mathematical models of IRE
which employed deterministic models show a sharp transition line.
Obviously, knowing precisely the extent of complete tissue ablation is
important in treatment of cancer. The mode of analysis and treatment
planning design presented in this study may become important in attempts
to optimize the use of NTIRE in treatment of cancer.
Conclusion
This study has introduced a new
mathematical methodology for analysis of tissue ablation by irreversible
electroporation using statistical models of cell death. The methodology
was illustrated using data derived from single cell studies. Much
experimental work remains to obtain similar data for cells in tissue.
However, once the experimental data becomes available, the use of a
statistical model rather than a deterministic model for IRE cell death
will improve the accuracy of treatment planning for cancer treatment
with IRE.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
AG performed data collection
modeling and drafted the manuscript. BR conceived of the study and
drafted the manuscript. All authors read and approved the final
manuscript.
Acknowledgements
This study was supported by the Israel Science Foundation grant # 403/06.
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Extremely low frequency (ELF) pulsed-gradient magnetic fields inhibit malignant tumour growth at different biological levels.
Zhang X, Zhang H, Zheng C, Li C, Zhang X, Xiong W.
Source
Biomedical Physics Unit, Department of Physics, Wuhan University, Wuhan, 430072, China.
Abstract
Extremely low frequency (ELF) pulsed-gradient magnetic field (with
the maximum intensity of 0.6-2.0 T, gradient of 10-100 T.M(-1), pulse
width of 20-200 ms and frequency of 0.16-1.34 Hz treatment of mice can
inhibit murine malignant tumour growth, as seen from analyses at
different hierarchical levels, from organism, organ, to tissue, and down
to cell and macromolecules. Such magnetic fields induce apoptosis of
cancer cells, and arrest neoangiogenesis, preventing a supply developing
to the tumour. The growth of sarcomas might be amenable to such new
method of treatment.
Technol Health Care. 2011;19(6):455-67.
Solid Ehrlich tumor growth treatment by magnetic waves.
Ali FM, El Gebaly RH, El Hag MA, Rohaim AM.
Source
Department of Biophysics, Faculty of Science, Cairo University, Giza, Egypt.
Abstract
In this work the retardation of Ehrlich tumor growth implanted in
mice was studied by employing 4.5 Hz magnetic field. Eighty female
Balb/c mice were used, twenty as normal group; the other sixty mice were
inoculated with Ehrlich tumor, then they were divided equally into
three groups namely A, B and C. Group A (control group) animals were not
exposed to the magnetic field. The tumors in the thigh of the animals
of group B were exposed to 4.5 Hz, 2 Gauss square wave magnetic field by
using a small solenoid connected to a power square wave generator.
Group C animals were whole body exposed inside a large solenoid to 4.5
Hz, 2 Gauss square wave magnetic field. Both groups B and C were exposed
for a period of 2 weeks at a rate 2 hours per day. Tumor volume,
survival period, histological examination and dielectric relaxation of
the tumor were measured to investigate the activity of the tumor of the
exposed and the unexposed animals. The results indicated that exposing
the tumor tissue to 4.5 Hz square wave magnetic field for 2 weeks at a
rate 2 hours/day inhibited tumor growth and increased the survival
period of the animals. However, group B showed more improvements than
did group C. This was attributed to some distortions in the square
waveform in the large solenoid (group C). By comparing data from current
and previous work, it was concluded that the use of magnetic waves
showed better results over previously published work using amplitude
modulated electromagnetic waves with the same frequency.
Tumor treating fields: concept, evidence and future.
Pless M, Weinberg U.
Source
Medical Oncology, Department of Internal Medicine, and Tumor Center,
Kantonsspital Winterthur, Brauerstrasse, Switzerland.
miklos.pless@ksw.ch
Abstract
INTRODUCTION: Local control is fundamental, both for the curative as
well as the palliative treatment of cancer. Tumor treating fields
(TTFields) are low intensity (1 2 V/cm), intermediate frequency (100 ?
200 kHz) alternating electric fields administered using insulated
electrodes placed on the skin surrounding the region of a malignant
tumor. TTFields were shown to destroy cells within the process of
mitosis via apoptosis, thereby inhibiting tumor growth. TTFields have no
effect on non-dividing cells.
AREAS COVERED: This article reviews in vitro and in vivo preclinical
studies, demonstrating the activity of TTFields both as a monotherapy as
well as in combination with several cytotoxic agents. Furthermore, it
summarizes the clinical experience with TTFields, mainly in two
indications: one in recurrent glioblastoma multiforme: in a large
prospective randomized Phase III trial TTFields was compared with best
standard care (including chemotherapy): TTFields significantly improved
median overall survival (OS) compared with standard therapy (7.8 vs 6.1
months) for the patients treated per protocol. Importantly, quality of
life was also better in the TTFields group. The second indication was a
Phase II study in second-line non-small cell lung cancer, where TTFields
was administered concomitantly with pemetrexed. This combination
resulted in an excellent median OS of 13.8 months. Interestingly, the
progression-free survival (PFS) within the area of the TTFields was 28,
however, outside the TTFields the PFS was only 22 weeks.
EXPERT OPINION: The proof of concept of TTFields has been well
demonstrated in the preclinical setting, and the clinical data seem
promising in various tumor types. The side effects of TTFields were
minimal and in general consisted of skin reaction to the electrodes.
There are a number of ways in which TTFields could be further evaluated,
for example, in combination with chemotherapy, as a maintenance
treatment, or as a salvage therapy if radiotherapy or surgery is not
possible. While more clinical data are clearly needed, TTFields is an
emerging and promising novel treatment concept.
Br J Cancer. Aug 23, 2011; 105(5): 640–648.
Published online Aug 9, 2011. doi: 10.1038/bjc.2011.292
PMCID: PMC3188936
Treatment of advanced hepatocellular carcinoma with very low levels of amplitude-modulated electromagnetic fields
Therapeutic options for patients
with advanced hepatocellular carcinoma (HCC) are limited. There is
emerging evidence that the growth of cancer cells may be altered by very
low levels of electromagnetic fields modulated at specific frequencies.
Methods:
A single-group, open-label, phase
I/II study was performed to assess the safety and effectiveness of the
intrabuccal administration of very low levels of electromagnetic fields
amplitude modulated at HCC-specific frequencies in 41 patients with
advanced HCC and limited therapeutic options. Three-daily 60-min
outpatient treatments were administered until disease progression or
death. Imaging studies were performed every 8 weeks. The primary
efficacy end point was progression-free survival 6 months. Secondary efficacy end points were progression-free survival and overall survival.
Results:
Treatment was well tolerated and
there were no NCI grade 2, 3 or 4 toxicities. In all, 14 patients
(34.1%) had stable disease for more than 6 months. Median
progression-free survival was 4.4 months (95% CI 2.1–5.3) and median
overall survival was 6.7 months (95% CI 3.0–10.2). There were three
partial and one near complete responses.
Conclusion:
Treatment with intrabuccally
administered amplitude-modulated electromagnetic fields is safe, well
tolerated, and shows evidence of antitumour effects in patients with
advanced HCC.Keywords: hepatocellular carcinoma, phase II study, radiofrequency electromagnetic fields, tumour-specific modulation frequencies, 27.12MHz
Treatment of inoperable or metastatic
solid tumours is a major challenge in oncology, which is limited by the
small number of therapeutic agents that are both well tolerated and
capable of long-term control of tumour growth. Hepatocellular carcinoma
(HCC) is the second most common cause of cancer death in men and the
sixth in women worldwide (Jemal et al, 2011).
Hepatocellular carcinoma is the most common tumour in certain parts of
the world, particularly in East Asia, Africa, and certain countries of
South America. This tumour is less frequent in Europe and in the United
States, but has become the fastest rising cancer in the United States (Jemal et al, 2011). In the United States alone, it is estimated that 24120 new cases were diagnosed and there were 17430 deaths from HCC in 2010 (Jemal et al, 2010), a 27% increase in the number of new cases since 2004 (Jemal et al, 2004). The prognosis of patients suffering from advanced HCC is poor with an average survival of fewer than 6 months (Kassianides and Kew, 1987; Jemal et al, 2011).
Therapies for HCC are limited. Resections of the primary
tumour or liver transplantation are the preferred therapeutic approaches
in patients who are surgical candidates (Bruix and Sherman, 2005).
Although these interventions result in long-term survival for some
patients, only a minority benefit from them because of limitations due
to tumour size, patient’s overall condition, and presence of hepatic
cirrhosis (Cance et al, 2000).
Only a small number of randomised trials show a survival benefit in the
treatment of HCC. Chemoembolisation has been shown to confer a survival
benefit in selected patients with unresectable HCC (Llovet et al, 2002).
Data from two phase III randomised placebo-controlled studies
demonstrate improved survival in patients with advanced HCC receiving
the multikinase inhibitor sorafenib (Llovet et al, 2008b; Cheng et al, 2009).
Additional therapies for this disease are sorely needed, especially for
the large number of patients with advanced disease who cannot tolerate
chemotherapy or intrahepatic interventions because of impaired liver
function (Thomas and Zhu, 2005).
The intrabuccal administration of low and safe
levels of electromagnetic fields, which are amplitude-modulated at
disease-specific frequencies (RF AM EMF) (Figure 1), was originally developed for the treatment of insomnia (Pasche et al, 1990).
The highest levels of EMFs encountered during treatment are found at
the interface between the tongue and the mouth probe and are compliant
with international safety limits (ICNIRP, 1998; Pasche and Barbault, 2003).
Tumour-specific modulation frequencies have been identified for several
common forms of cancer and one report suggests that this novel
therapeutic approach is well tolerated and may be effective in patients
with a diagnosis of cancer (Barbault et al, 2009).
However, the safety and potential efficacy of this treatment approach
in the treatment of advanced HCC are unknown. We designed this
single-group, open-label, phase I/II study to assess the feasibility of
this treatment in patients with advanced HCC and limited therapeutic
options.
Figure 1
Delivery of HCC-specific modulation frequencies. (A) The generator of AM EMFs is a battery-driven RF EMF generator connected to a spoon-shaped mouthpiece. (B) Schematic description of AM EMFs. The carrier frequency (27.12MHz) is sinusoidally …Go to:
Patients and methods
Patients
The study was aimed at offering
treatment to patients with Child–Pugh A or B advanced HCC and limited
therapeutic options. Patients were classified as having advanced disease
if they were not eligible for surgical resection or had disease
progression after surgical or locoregional therapies or had disease
progression after chemotherapy or sorafenib therapy. Patients with
measurable, inoperable HCC were eligible for enrolment. Previous local
or systemic treatments were allowed as long as they were discontinued at
least 4 weeks before enrolment. Inclusion criteria included Eastern
Cooperative Oncology Group performance status of 0, 1, or 2 and
biopsy-confirmed HCC. Also allowed were patients with no pathological
confirmation of HCC with a level of ?-fetoprotein higher than 400ngml?1
and characteristic imaging findings as assessed by multislice computer
tomography (CT) scan or intravenous contrast ultrasound (US). As per the
University of São Paulo Department of Transplantation and Liver Surgery
guidelines, liver biopsies are avoided in patients eligible for
transplant or with severely impaired liver function. Exclusion criteria
included confirmed or suspected brain metastasis, Child–Pugh C, previous
liver transplant, and pregnancy.
Study design
This was an investigator-initiated,
single centre, uncontrolled phase I/II trial in patients with advanced
HCC. The trial was approved by the local human investigation committee
and conducted in accordance with the Declaration of Helsinki. Written
informed consent was obtained from each patient. The protocol was
registered: clinicaltrial.gov identifier no. NCT00534664.
Administration of AM EMFs
The generator of AM EMFs consists of a battery-driven radiofrequency (RF) EMF generator connected to a 1.5m long 50? coaxial cable, to the other end of which a stainless-steel spoon-shaped mouthpiece is connected via an impedance transformer (Figure 1A). The RF source of the device corresponds to a class C amplifier operating at 27.12MHz. The carrier frequency is AM (Figure 1B)
with a modulation depth of 85±5%, whereas the modulation frequency is
generated by a digital direct synthesiser with a resolution of 10?7.
The treatment sequence is controlled by a microcontroller (Atmel
AT89S8252, Fribourg, Switzerland), that is, duration of session,
sequence of modulation frequencies and duration of each sequence can be
programmed via PC over a RS232 interface. The RF output is adjusted to
100mW into a 50? load, which results in an emitting power identical to that of the device used for the treatment of insomnia (Pasche et al, 1990; Reite et al, 1994; Pasche et al, 1996).
The United States Food and Drug Administration has determined that such
a device is not a significant risk device and it has been used in
several studies conducted in the United States (Reite et al, 1994; Pasche et al, 1996; Kelly et al, 1997).
A long-term follow-up survey of 807 patients who have received this
therapy in the United States, Europe and Asia showed that the rate of
adverse reactions was low and was not associated with increases in the
incidence of malignancy or coronary heart disease (Amato and Pasche, 1993). The maximum specific absorption rate (SAR) of the applied RF averaged over any 10g of tissue has been estimated to be less than 2Wkg?1,
and the maximum temperature increase is significantly lower than 1°C
anywhere in the body owing to RF absorption. The induced RF field values
within the primary and metastatic tumours are significantly lower. In
contrast, the RF fields induced during RF ablation of tumours cause
hyperthermia and result in SAR in the range of 2.4 × 105Wkg?1 (Chang, 2003), that is, more than 100000 times higher than those delivered by the device used in this study.
We have previously reported the discovery of HCC-specific
modulation frequencies in 46 patients with HCC using a patient-based
biofeedback approach and shown the feasibility of using AM EMFs for the
treatment of patients with cancer (Barbault et al, 2009). The treatment programme used in this study consisted of three-daily outpatient treatments of 1h duration, which contained HCC-specific modulation frequencies ranging between 100Hz and 21kHz administered sequentially, each for 3s (Figure 1C and Supplementary Table S1).
The treatment method consists of the
administration of AM EMFs by means of an electrically conducting
mouthpiece, which is in direct contact with the oral mucosa (Figure 1D).
The patients were instructed on the use of the device and received the
first treatment at the medical centre’s outpatient clinic. A device was
provided to each patient for the duration of the study. The patients
were advised to self-administer treatment three times a day. Treatment
was administered until tumour progression was objectively documented. At
that time, treatment was discontinued. Treatment compliance was
assessed at every return visit by recording the number of treatments
delivered in the preceding 2 months.
Efficacy end points and disease assessment
The primary end point of this trial
was the proportion of patients progression-free at 6 months. Secondary
end points were progression-free survival (PFS) (first day of treatment
until progression of disease or death) and overall survival (OS) (first
day of receiving treatment to death). Objective response was assessed
using the Response Evaluation Criteria in Solid Tumours group
classification for patients with disease assessed by either helical
multiphasic CT (Therasse et al, 2000).
Whenever contrast-enhanced US radiological assessment was used, it was
performed and reviewed by the same radiologist specialised in HCC (MCC)
as this imaging modality is investigator dependent. Tumour measurements
were performed at baseline and every 8 weeks. Only patients with at
least one repeat tumour measurement during therapy were considered for
response analysis. Throughout the study, lesions measured at baseline
were evaluated using the same technique (CT or contrast-enhanced US).
Overall tumour response was scored as a complete response (CR), partial
response (PR), or stable disease (SD) if the response was confirmed at
least 4 weeks later. Alpha-fetoprotein (AFP) levels were measured every 8
weeks in all patients throughout the study, but changes in AFP were not
an end point for assessment of response. Pain was assessed according to
the NCI-CTCAE v.3.0 (http://ctep.cancer.gov/protocolDevelopment/electronic_applications/docs/ctcaev3.pdf).
Statistical analyses and efficacy assessment
All eligible patients who began
treatment were considered assessable for the primary and secondary end
points. A Simon two-stage phase II minimax design was used (Simon, 1989)
to evaluate the rate of progression-free survival at 6 months. The
interim analysis was performed once enrolment into the first stage was
completed. In the first stage, 23 patients were observed. If two or
fewer patients had progression-free survival 6
months, the trial would be terminated early for lack of efficacy. If
the progression-free survival of 3 or more of the first 23 patients was
equal or greater than 6 months, then an additional 18 patients would be
enrolled to a maximum of 41 patients. If eight or more of the 41 had PFS
of at least 6 months, we would conclude that the treatment was
efficacious. This design had a Type I error rate of 5% and a Type II
error rate of 10% for the null hypothesis of a 6-month PFS rate of 10%
vs the alternative of 27.5%. Kaplan–Meier estimates of survival, PFS,
and duration of response were calculated with standard errors based on
Greenwood’s formula. These calculations were performed using the Proc
Lifetest in SAS 9.2 (SAS Institute Inc., Cary, NC, USA).
Results
Patient recruitment and follow-up
From October 2005 to July 2007, 267 patients were assessed for eligibility (Figure 2).
In all, 43 patients with advanced HCC and Child–Pugh A or B were
enrolled in this study. The date of last patient follow-up is 9 June
2011. Of these, 20 patients (46.5%) had histological confirmation of
HCC; 23 patients (53.5%) were diagnosed based on elevated levels of ?-fetoprotein
and characteristic imaging findings such as vascular invasion and
characteristic differences in tumour blood flow. One patient was
excluded because liver biopsy established the diagnosis of metastatic
breast cancer. Another patient was excluded because of severely impaired
liver function (Child–Pugh C11). These two patients who did not meet
the inclusion criteria were registered as screening failures. Hence, a
total of 41 patients were eligible to receive experimental therapy (Figure 2).
Two patients were lost to follow-up as they did not come
back for their scheduled appointments. Repeated efforts were made to
reach the patients and their families. The date of death of only one
patient is known, and no information on response to treatment is
available for either patient. Four patients withdrew consent while
receiving therapy after 8.0, 9.3, 20.3, and 21.0 months, respectively (Figure 2).
One patient elected to receive chemotherapy, one patient had poor
treatment compliance as defined by administration of less than 50% of
planned treatments at two consecutive return visits, one patient elected
to enrol in another experimental protocol, and one patient requested to
be considered for liver transplantation as part of an extended
indication, which does not fulfil the Milan criteria (Mazzaferro et al, 1996).
This latter patient experienced disease progression and was ultimately
not eligible for liver transplantation. Of the 35 patients who
discontinued experimental therapy, four died of gastrointestinal
bleeding, three of sepsis, three of hepatic failure, one of chronic
obstructive pulmonary disease, two of chemotherapy- and
chemoembolisation-related complications, and one of myocardial
infarction (Figure 2).
The remaining 24 patients discontinued because of disease progression
assessed by imaging or significant clinical deterioration as assessed by
the investigator (Figure 2).
Estimated 60-day mortality was 27.8% seven of 10 deaths were directly
related to progression of disease. They were caused by liver failure in
association with significant hepatic tumour involvement, without other
cause of death, other than tumour involvement. Two deaths were secondary
to gastrointestinal bleeding. One death was due to liver failure.
A total of 31 patients (75.6%) had
radiological evidence of disease progression at the time of enrolment as
defined by comparison of baseline imaging studies, with imaging studies
obtained within the previous 6 months; 34 (82.9%) patients had received
therapy before enrolment, five (14.6%) of them systemic chemotherapy or
sorafenib (Table 1).
Seven (17.1%) patients had not received therapy before enrolment for
the following reasons: (1) severely impaired liver function in five
cases; and (2) two patients refused to receive chemotherapy for
metastatic disease. As shown in Table 2,
the majority of patients had severely impaired liver function as
demonstrated by the fact that 22 (53.7%) patients had Child–Pugh B
disease and 35 (85.4%) BLCL stage C disease.
Table 1Treatments received by patients with advanced HCC before enrolment (n=41)
Six of the first 23 patients (26.1%) had progression-free survival 6 months, which led us to continue enrolling patients up to the preplanned total of 41 patients (Figure 2).
In total, 14 patients (34.1%) had SD for more than 6 months, which met
our preplanned primary efficacy end point. Median progression-free
survival was 4.4 months (95% CI 2.1–5.3) and median OS was 6.7 months
(95% CI 3.0–10.2) (Figure 3A and B). One patient, previously enrolled in the SHARP study (Llovet et al, 2008b)
and with evidence of disease progression at the time of enrolment,
remains on therapy with a near complete response for 58 months (Figure 3C).
Estimated survival at 12, 24 and 36 months is 27.9% (s.e.=7.1%), 15.2%
(s.e.=5.7%), and 10.1% (s.e.=4.8%), respectively. Subset analyses by
Child-Pugh stage and accompanying figures are reported in Supplementary
Information.
Figure 3
Progression-free and overall survival. (A) Median progression-free survival was 4.4 months (95% CI 2.1–5.3). (B) Median overall survival was 6.7 months (95% CI 3.0–10.2). (C) Long-term partial response in a patient with …
A total of 28 patients were evaluable for tumour response (Figure 2). Four (9.8%) patients had a partial response assessed with CT with or without contrast-enhanced ultrasound (Table 3).
All partial responses were independently reviewed by two authors (MSR
and DM). Three patients had biopsy-confirmed HCC and three had
radiological evidence of disease progression at the time of enrolment (Table 4).
Two patients had Child–Pugh A, one Child–Pugh B disease, and one had no
cirrhosis. One of these patients without biopsy-proven disease
subsequently withdrew consent after 4.9 months to undergo liver
transplantation. The patient died of progression of disease 9.4 months
later before undergoing liver transplantation. One patient with
Child–Pugh B disease had a partial response lasting 11.7 months and died
of gastrointestinal bleeding. One patient died of disease progression
at 44.6 months. Overall, there were six long-term survivors with an OS
greater than 24 months and four long-term survivors with an OS greater
than 3 years. Importantly, five of the six (83%) long-term survivors had
radiological evidence of disease progression at the time of study
enrolment (Table 4).
Two of three patients with the longest survival (44.6 and +58 months)
had radiological evidence of disease progression at the time of
enrolment, BLCL stage C disease, as well as portal vein thrombosis,
three predictors of short survival (Llovet et al, 2003). Serial AFP measurements, which predict radiological response and survival in patients with HCC (Chan et al, 2009; Riaz et al, 2009), were available for 23 patients. AFP decreased by 20% or more in four (9.8%) patients following initiation of therapy (Table 5). Figure 3D
shows the time course of a 37-fold decrease in AFP in a patient who had
a long-lasting (11.7 months) partial response as assessed by CT.
Table 3Independently reviewed best response (N=41)
Table 4Characteristics of patients with either PR and/or long-term survival in excess of 24 months
In all, 11 patients reported pain before
treatment initiation, 3 patients reported grade 3, 5 patients reported
grade 2, and 3 patients grade 1. Five patients reported complete
disappearance of pain and two patients reported decreased pain shortly
after treatment initiation. Two patients reported no changes and two
patients reported increased pain. There were no treatment-related grade
2, 3, or 4 toxicities. The only treatment-related adverse events were
grade 1 mucositis (one patient) and grade 1 somnolence (one patient)
over a total of 266.8 treatment months.Go to:
Discussion
Treatment with AM EMFs did not show any
significant toxicity despite long-term treatment. The lack of toxicity
experienced by the 41 patients presented in this report as well as the
28 patients from our previous report (Barbault et al, 2009) can be readily explained by the very low and safe levels of induced RF EMFs, which are more than 100000 times lower than those delivered during RF ablation procedures (Chang, 2003).
Hence, the putative mechanism of action of this novel therapeutic
approach does not depend on temperature changes within the tumour.
These data are comparable to recent phase II studies
evaluating the effectiveness of standard chemotherapy as well as novel
targeted therapies in HCC (Abou-Alfa et al, 2006; Boige et al, 2007; Chuah et al, 2007; Cohn et al, 2008; Dollinger et al, 2008; Siegel et al, 2008).
In a large phase II study assessing the effects of sorafenib in
patients with HCC and Child–Pugh A and B who had not received previous
systemic treatment, Abou-Alfa et al (2006)
observed partial responses using the WHO criteria in 2.2% of patients.
Investigator-assessed median time to progression was 4.2 months, and
median OS was 9.2 months. Of note, all 137 patients from that study had
evidence of disease progression after 14.8 months (Abou-Alfa et al, 2006),
whereas, at the same time point, four (9.8%) of the patients enrolled
in this study did not have evidence of disease progression. These
findings suggest that RF AM EMF may increase the time to radiological
progression in advanced HCC.
The majority of patients enrolled in this study had either
failed standard treatment options or had severely impaired liver
function that limited their ability to tolerate any form of systemic or
intrahepatic therapy. Indeed, 16 patients (39.0%) had Child–Pugh B8 or
B9 disease. Among these patients, the median progression-free survival
was 4.4 months (95% CI 1.6–7.6 months), which is identical to that of
the entire group. Five of these 16 patients (31.3%) received therapy for
more than 7.5 months, which indicates that this therapy is well
tolerated even in patients with severely impaired liver function.
Previous treatment with standard chemotherapy or sorafenib
does not seem to impact the effectiveness of AM EMFs in the treatment
of HCC. Indeed, three of the four patients who had a partial response
while receiving AM EMFs had received previous systemic therapies
(chemotherapy and sorafenib) and one had received intrahepatic therapy
with 131I-lipiodol.
Tumour shrinkage as assessed by radiological imaging as
well as changes in AFP levels were documented in patients with advanced
HCC receiving RF EMF modulated at HCC-specific frequencies administered
by an intrabuccal probe. Antitumour activity in patients with advanced
HCC was exemplified by partial responses observed in four patients
(9.8%) and decreases in AFP levels greater than 20% in four patients. A
total of 18 patients (43.9%) either had objective response or SD 6 months.
Importantly, this therapeutic approach has long-lasting
therapeutic effects in several patients with metastatic cancer. Two of
these patients, one with recurrent thyroid cancer metastatic to the
lungs (Figure 4) enrolled in our feasibility study (Barbault et al, 2009) and the patient shown in Figure 3C,
are still receiving treatment without any evidence of disease
progression and without side effects almost 5 years after being enrolled
in these studies. These findings suggest that, in some patients, this
therapeutic approach may achieve permanent control of advanced cancer
with virtually no toxicity.
Figure 4
A 70-year-old man with recurrent thyroid cancer metastatic to the
lungs: stable disease at 57.5 months. Long-term stable disease in a
70-year-old man with recurrent biopsy-proven thyroid carcinoma
metastatic to the lungs enrolled in the previously published…
Our phase I/II study has several limitations. First, only
19 of the 41 patients had biopsy-proven HCC, and the others were
diagnosed by clinical criteria, an approach similar to that used in a
recently reported phase II trial evaluating the clinical and biological
effects of bevacizumab in unresectable HCC (Siegel et al, 2008).
Importantly, analysis restricted to these 19 patients shows rates of
progression-free survival at 6 months, median progression-free survival
and OS that are similar to those without biopsy-proven HCC
(Supplementary Figures 1C and D). Furthermore, three of the four partial
responses were observed in patients with biopsy-proven HCC. Hence,
these findings strongly suggest that treatment with AM EMFs yields
similar results in patients with and without biopsy-confirmed HCC.
Another potential limitation of our study consists in the use of
contrast-enhanced ultrasound for the monitoring of some patients with
HCC. It should be pointed out that recent studies indicate that the use
of this imaging technique is comparable to that of CT scan with respect
to the measurement of HCC tumours (Choi, 2007; Maruyama et al, 2008).
Antitumour response is considered the
primary end point for phase II studies to proceed to further
investigations. Studies applying Cox proportional hazards analysis
indicate that this end point is consistently associated with survival in
trials of locoregional therapies for HCC (Llovet et al, 2002)
and a recent consensus article suggests that randomised studies are
necessary to capture the true efficacy of novel therapies in HCC (Llovet et al, 2008a).
In summary, the encouraging findings from this study warrant a
randomised study to determine the impact of AM EMFs on OS and time to
symptomatic progression.
Acknowledgments
We thank Drs Al B Benson III, Northwestern University and
Leonard B Saltz, Memorial Sloan-Kettering Cancer Center for reviewing
the manuscript.
Notes
AB and BP have filed a patent related to the use of
electromagnetic fields for the diagnosis and treatment of cancer. AB and
BP are founding members of TheraBionic LLC.
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Electromagn Biol Med. 2010 Dec;29(4):132-43.
Bioelectromagnetic field effects on cancer cells and mice tumors.
Berg H, Günther B, Hilger I, Radeva M, Traitcheva N, Wollweber L.
We present possibilities and trends of ELF bioelectromagnetic effects
in the mT amplitude range on cancer cells and on mice bearing tumors.
In contrast to invasive electrochemotherapy and electrogenetherapy,
using mostly needle electrodes and single high-amplitude electropulses
for treatment, extremely low-frequency (ELF) pulsating electromagnetic
fields (PEMF) and sinusoidal electromagnetic fields (SEMF) induce tumor
cell apoptosis, inhibit angiogenesis, impede proliferation of neoplastic
cells, and cause necrosis non invasively, whereas human lymphocytes are
negligibly affected. Our successful results in killing cancer
cells-analyzed by trypan blue staining or by flow cytometry-and of the
inhibition of MX-1 tumors in mice by 15-20?mT, 50?Hz treatment in a
solenoid coil also in the presence of bleomycin are presented in
comparison to similar experimental results from the literature. In
conclusion, the synergistic combinations of PEMF or SEMF with
hyperthermia (41.5°C) and/or cancerostatic agents presented in the
tables for cells and mice offer a basis for further development of an
adjuvant treatment for patients suffering from malignant tumors and
metastases pending the near-term development of suitable solenoids of
45-60?cm in diameter, producing >20?mT in their cores.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2010 Oct;27(5):1128-32.
Focusing properties of picosecond electric pulses in non-invasive cancer treatment.
[Article in Chinese]
Long Z, Yao C, Li C, Mi Y, Sun C.
Source
State Key Laboratory of Power Transmission Equipment
& System Security and New Technology, Chongqing University,
Chongqing 400044, China. longzaiquan@foxmail.com
Abstract
In the light of optical theory, we advanc an
ultra-wideband impulse radiating antenna (IRA) which is composed of an
ellipsoidal reflector and a cone radiator. The high-intensity
ultra-short electric pulses radiated by IRA can be transferred into the
deep target in tissue non-invasively and be focused effectively. With
the focused picosecond electric pulses, the organelles (mitochondria)
transmembrane potential shall change to collapse under which the tumor
cells will be targetly induced to apoptosis, so the method of
non-invasive treatment of tumors would be achieved. Based on the
time-domain electromagnetic field theory, the propagation
characteristics of picosecond electric pulses were analyzed with and
without the context of biological tissue, respectively. The results show
that the impulse characteristics of input pulse were maintained and the
picosecond electric pulses can keep high resolution in target areas.
Meanwhile, because of the dispersive nature of medium, the pulse
amplitude of the pulses will attenuate and the pulse width will be
broadened.
BMC Cancer. 2010 Apr 24;10:159.
Anti-proliferative effect of extremely low frequency electromagnetic field on preneoplastic lesions formation in the rat liver.
Department of Physics Center of Research and Advanced Studies of the National Polytechnic Institute, Mexico City, Mexico. jj@fis.cinvestav.mx
Abstract
BACKGROUND: Recently, extremely low frequency electromagnetic fields
(ELF-EMF) have been studied with great interest due to their possible
effects on human health. In this study, we evaluated the effect of 4.5
mT-120 Hz ELF-EMF on the development of preneoplastic lesions in
experimental hepatocarcinogenesis.
METHODS: Male Fischer-344 rats were subjected to the modified
resistant hepatocyte model and were exposed to 4.5 mT – 120 Hz ELF-EMF.
The effects of the ELF-EMF on hepatocarcinogenesis, apoptosis,
proliferation and cell cycle progression were evaluated by
histochemical, TUNEL assay, caspase 3 levels, immunohistochemical and
western blot analyses.
RESULTS: The application of the ELF-EMF resulted in a decrease of
more than 50% of the number and the area of gamma-glutamyl
transpeptidase-positive preneoplastic lesions (P = 0.01 and P = 0.03,
respectively) and glutathione S-transferase placental expression (P =
0.01). The number of TUNEL-positive cells and the cleaved caspase 3
levels were unaffected; however, the proliferating cell nuclear antigen,
Ki-67, and cyclin D1 expression decreased significantly (P < or =
0.03), as compared to the sham-exposure group.
CONCLUSION: The application of 4.5 mT-120 Hz ELF-EMF inhibits
preneoplastic lesions chemically induced in the rat liver through the
reduction of cell proliferation, without altering the apoptosis process.
Cell Biochem Biophys. 2009;55(1):25-32. Epub 2009 Jun 18.
Evaluation of the potential in vitro antiproliferative effects of
millimeter waves at some therapeutic frequencies on RPMI 7932 human skin
malignant melanoma cells.
Beneduci A.
Department of Chemistry, University of Calabria, Via P. Bucci, Cubo 17/D, Arcavacata di Rende (CS), Italy.beneduci@unical.it
Abstract
The potential antiproliferative effects of low power millimeter waves
(MMWs) at 42.20 and 53.57 GHz on RPMI 7932 human skin melanoma cells
were evaluated in vitro in order to ascertain if these two frequencies,
comprised in the range of frequency used in millimeter wave therapy,
would have a similar effect when applied in vivo to malignant melanoma
tumours. Cells were exposed for 1 h exposure/day and to repeated
exposure up to a total of four treatments. Plane wave incident power
densities <1 mW/cm(2) were used in the MMWs-exposure experiments so
that the radiations did not cause significant thermal effects. Numerical
simulations of Petri dish reflectivity were made using the equations
for the reflection coefficient of a multilayered system. Such analysis
showed that the power densities transmitted into the aqueous samples
were < or = 0.3 mW/cm(2). Two very important and general biological
endpoints were evaluated in order to study the response of melanoma
cells to these radiations, i.e. cell proliferation and cell cycle.
Herein, we show that neither cell doubling time nor the cell cycle of
RPMI 7932 cells was affected by the frequency of the GHz radiation and
duration of the exposure, in the conditions above reported.
— ————————————————————————————
Bioelectrochemistry. 2010 Oct;79(2):257-60. Epub 2010 Mar 10.
Electroporation and alternating current cause membrane permeation of
photodynamic cytotoxins yielding necrosis and apoptosis of cancer
cells.
Traitcheva N, Berg H.
Institute of Plant Physiology “M. Popov,” Bulgarian Acad. of Sciences, Sofia, Bulgaria.
Abstract
In order to increase the permeability of cell membranes for low doses
of cytostatic drugs, two bioelectrochemical methods have been compared:
(a) electric pore formation in the plasma membranes by single electric
impulses (electroporation), and (b) reordering of membrane structure by
alternating currents (capacitively coupled). These treatments were
applied to human leukemic K-562 cells and human lymphoma U-937 cells,
yielding apoptotic and necrotic effects, determined by flow cytometry.
Additional cell death occurs after exposure to light irradiation at
wavelengths lambda > 600 nm, of cells which were electroporated and
had incorporated actinomycin-C or daunomycin (daunorubicin). It is
observed that drug uptake after an exponentially decaying
electroporation pulse of the initial field strength Eo=1.4 kV/cm and
pulse time constants in the time range 0.5-3 ms is faster than during
PEMF-treatment, i.e., application of an alternating current of 16 kHz,
voltage U<100 V, I=55 mA, and exposure time 20 min. However, at the
low a.c. voltage of this treatment, more apoptotic and necrotic cells
are produced as compared to the electroporation treatment with one
exponentially decaying voltage pulse. Thus, additional photodynamic
action appears to be more effective than solely drugs and
electroporation as applied in clinical electrochemotherapy, and more
effective than the noninvasive pulsed electromagnetic fields (PEMFs),
for cancer cells in general and animals bearing tumors in particular.
Arch Biochem Biophys. 2010 May;497(1-2):82-9. Epub 2010 Mar 24.
Nanosecond pulsed electric fields stimulate apoptosis without
release of pro-apoptotic factors from mitochondria in B16f10 melanoma.
Ford WE, Ren W, Blackmore PF, Schoenbach KH, Beebe SJ.
Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA.
Abstract
Nanosecond pulsed electric fields (nsPEFs) eliminates B16f10 melanoma
in mice, but cell death mechanisms and kinetics of molecular events of
cell death are not fully characterized. Treatment of B16f10 cells in
vitro resulted in coordinate increases in active caspases with YO-PRO-1
uptake, calcium mobilization, decreases in mitochondria membrane
potential with decreases in forward light scatter (cell size), increases
in ADP/ATP ratio, degradation of actin cytoskeleton and membrane
blebbing. However, there was no mitochondrial release of cytochrome c,
AIF or Smac/DIABLO or generation of reactive oxygen species.
Phosphatidylserine externalization was absent and propidium iodide
uptake was delayed in small populations of cells. The results indicate
that nsPEFs rapidly recruit apoptosis-like mechanisms through the plasma
membrane, mimicking the extrinsic apoptosis pathway without
mitochondrial amplification yet include activation of initiator and
executioner caspases. nsPEFs provide a new cancer therapy that can
bypass cancer-associated deregulation of mitochondria-mediated apoptosis
in B16f10 melanoma.
J Physiol Pharmacol. 2010 Apr;61(2):201-5.
Pulsating electromagnetic field stimulation prevents cell death of puromycin treated U937 cell line.
Kaszuba-Zwoinska J, Wojcik K, Bereta M, Ziomber A, Pierzchalski P, Rokita E, Marcinkiewicz J, Zaraska W, Thor P.
Department of Pathophysiology, Jagiellonian University Medical College, Cracow, Poland. jkaszuba@cm-uj.krakow.pl
Abstract
Aim of study was to verify whether pulsating electromagnetic field
(PEMF) can affect cancer cells proliferation and death. U937 human
lymphoid cell line at densities starting from 1 x 10(6) cells/ml to
0.0625 x 10(6) cells/ml, were exposed to a pulsating magnetic field 50
Hz, 45+/-5 mT three times for 3 h per each stimulation with 24 h
intervals. Proliferation has been studied by counting number of cells
stimulated and non-stimulated by PEMF during four days of cultivation.
Viability of cells was analyzed by APC labeled Annexin V and 7-AAD
(7-amino-actinomycin D) dye binding and flow cytometry. Growing
densities of cells increase cell death in cultures of U937 cells. PEMF
exposition decreased amount of cells only in higher densities.
Measurement of Annexin V binding and 7-AAD dye incorporation has shown
that density-induced cell death corresponds with decrease of
proliferation activity. PEMF potentiated density-induced death both
apoptosis and necrosis. The strongest influence of PEMF has been found
for 1 x 10(6)cells/ml and 0.5 x 10(6) cells/ml density. To eliminate
density effect on cell death, for further studies density 0.25 x 10(6)
cells/ml was chosen. Puromycin, a telomerase inhibitor, was used as a
cell death inducer at concentration 100 microg/ml. Combined interaction
of three doses of puromycin and three fold PEMF interaction resulted in a
reduced of apoptosis by 24,7% and necrosis by 13%. PEMF protects U937
cells against puromycin- induced cell death. PEMF effects on the human
lymphoid cell line depends upon cell density. Increased density induced
cells death and on the other hand prevented cells death induced by
puromycin.
Int J Radiat Biol. 2010 Feb;86(2):79-88.
Growth of injected melanoma cells is suppressed by whole body
exposure to specific spatial-temporal configurations of weak intensity
magnetic fields.
Hu JH, St-Pierre LS, Buckner CA, Lafrenie RM, Persinger MA.
Department of Biology, Laurentian University, Sudbury, Ontario, Canada.
Abstract
PURPOSE: To measure the effect of exposure to a specific
spatial-temporal, hysiologically-patterned electromagnetic field
presented using different geometric configurations on the growth of
experimental tumours in mice.
METHODS: C57b male mice were inoculated subcutaneously with B16-BL6
melanoma cells in two blocks of experiments separated by six months (to
control for the effects of geomagnetic field). The mice were exposed to
the same time-varying electromagnetic field nightly for 3 h in one of
six spatial configurations or two control conditions and tumour growth
assessed.
RESULTS: Mice exposed to the field that was rotated through the three
spatial dimensions and through all three planes every 2 sec did not
grow tumours after 38 days. However, the mice in the sham-field and
reference controls showed massive tumours after 38 days. Tumour growth
was also affected by the intensity of the field, with mice exposed to a
weak intensity field (1-5 nT) forming smaller tumours than mice exposed
to sham or stronger, high intensity (2-5 microT) fields. Immunochemistry
of tumours from those mice exposed to the different intensity fields
suggested that alterations in leukocyte infiltration or vascularisation
could contribute to the differences in tumour growth.
CONCLUSIONS: Exposure to specific spatial-temporal regulated
electromagnetic field configurations had potent effects on the growth of
experimental tumours in mice.
Melanoma Res. 2009 Aug 26. [Epub ahead of print]
Histopathology of normal skin and melanomas after nanosecond pulsed electric field treatment.
Department of Hepatobiliary Surgery, the First Affiliated Hospital
Zhejiang University School of Medicine, Hangzhou, Zhejiang, China bFrank
Reidy Research Center for Bioelectrics cDepartment of Biological
Sciences, Old Dominion University, Norfolk, Virginia, USA.
Abstract
Nanosecond pulsed electric fields (nsPEFs) can affect the
intracellular structures of cells in vitro. This study shows the direct
effects of nsPEFs on tumor growth, tumor volume, and histological
characteristics of normal skin and B16-F10 melanoma in SKH-1 mice. A
melanoma model was set up by injecting B16-F10 into female SKH-1 mice.
After a 100-pulse treatment with an nsPEF (40-kV/cm field strength;
300-ns duration; 30-ns rise time; 2-Hz repetition rate), tumor growth
and histology were studied using transillumination, light microscopy
with hematoxylin and eosin stain and transmission electron microscopy.
Melanin and iron within the melanoma tumor were also detected with
specific stains. After nsPEF treatment, tumor development was inhibited
with decreased volumes post-nsPEF treatment compared with control tumors
(P<0.05). The nsPEF-treated tumor volume was reduced significantly
compared with the control group (P<0.01). Hematoxylin and eosin stain
and transmission electron microscopy showed morphological changes and
nuclear shrinkage in the tumor. Fontana-Masson stain indicates that
nsPEF can externalize the melanin. Iron stain suggested nsPEF caused
slight hemorrhage in the treated tissue. Histology confirmed that
repeated applications of nsPEF disrupted the vascular network. nsPEF
treatment can significantly disrupt the vasculature, reduce subcutaneous
murine melanoma development, and produce tumor cell contraction and
nuclear shrinkage while concurrently, but not permanently, damaging
peripheral healthy skin tissue in the treated area, which we attribute
to the highly localized electric fields surrounding the needle
electrodes.
Cancer Biol Ther. 2009 Sep;8(18):1756-62. Epub 2009 Sep 17.
Static magnetic fields impair angiogenesis and growth of solid tumors in vivo.
Strelczyk D, Eichhorn ME, Luedemann S, Brix G, Dellian M, Berghaus A, Strieth S.
Walter-Brendel-Center for Experimental Medicine (WBex), Campus Grosshadern, University of Munich (LMU), Munich, Germany.
Abstract
Exposure to static magnetic fields (SMFs) results in a reduced blood
flow in tumor vessels as well as in activation and adherence of
platelets. Whether this phenomenon may have a significant functional
impact on tumors has not been investigated as yet. The aim of our study
was to evaluate the effects of prolonged exposure to SMFs on tumor
angiogenesis and growth. Experiments were performed in dorsal skinfold
chamber preparations of Syrian Golden hamsters bearing syngenic A-Mel-3
melanomas. On 3 d following tumor cell implantation one group of animals
was immobilized and exposed to a SMF of 586 mT for three h. Control
animals were immobilized for the same duration without SMF exposure.
Using in vivo-fluorescence microscopy the field effects on tumor
angiogenesis and microcirculation were analyzed for seven days. Tumor
growth was assessed by repeated planimetry of the tumor area during the
observation period. Exposure to SMFs resulted in a significant
retardation of tumor growth ( approximately 30%). Furthermore,
histological analysis showed an increased peri- and intratumoral edema
in tumors exposed to SMFs. Analysis of microcirculatory parameters
revealed a significant reduction of functional vessel density, vessel
diameters and red blood cell velocity in tumors after exposure to SMFs
compared to control tumors. These changes reflect retarded vessel
maturation by antiangiogenesis. The increased edema after SMF exposure
indicates an increased tumor microvessel leakiness possibly enhancing
drug-uptake. Hence, SMF therapy appears as a promising new anticancer
strategy-as an inhibitor of tumor growth and angiogenesis and as a
potential sensitizer to
J Exp Clin Cancer Res. 2009 Apr 14;28:51.
Amplitude-modulated electromagnetic fields for the treatment of
cancer: discovery of tumor-specific frequencies and assessment of a
novel therapeutic approach.
Barbault A, Costa FP, Bottger B, Munden RF, Bomholt F, Kuster N, Pasche B.
Cabinet Médical, Avenue de la Gare 6, Lausanne, Switzerland. alexandre.barbault@gmail.com
Abstract
PURPOSE: Because in vitro studies suggest that low levels of
electromagnetic fields may modify cancer cell growth, we hypothesized
that systemic delivery of a combination of tumor-specific frequencies
may have a therapeutic effect. We undertook this study to identify
tumor-specific frequencies and test the feasibility of administering
such frequencies to patients with advanced cancer.
PATIENTS AND METHODS: We examined patients with various types of
cancer using a noninvasive biofeedback method to identify tumor-specific
frequencies. We offered compassionate treatment to some patients with
advanced cancer and limited therapeutic options.
RESULTS: We examined a total of 163 patients with a diagnosis of
cancer and identified a total of 1524 frequencies ranging from 0.1 Hz to
114 kHz. Most frequencies (57-92%) were specific for a single tumor
type. Compassionate treatment with tumor-specific frequencies was
offered to 28 patients. Three patients experienced grade 1 fatigue
during or immediately after treatment. There were no NCI grade 2, 3 or 4
toxicities. Thirteen patients were evaluable for response. One patient
with hormone-refractory breast cancer metastatic to the adrenal gland
and bones had a complete response lasting 11 months. One patient with
hormone-refractory breast cancer metastatic to liver and bones had a
partial response lasting 13.5 months. Four patients had stable disease
lasting for +34.1 months (thyroid cancer metastatic to lung), 5.1 months
(non-small cell lung cancer), 4.1 months (pancreatic cancer metastatic
to liver) and 4.0 months (leiomyosarcoma metastatic to liver).
CONCLUSION: Cancer-related frequencies appear to be tumor-specific
and treatment with tumor-specific frequencies is feasible, well
tolerated and may have biological efficacy in patients with advanced
cancer.
J Ethnopharmacol. 2009 Jun 22;123(2):293-301. Epub 2009 Mar 24.
Induction of apoptosis in human hepatocarcinoma SMMC-7721 cells in vitro by flavonoids from Astragalus complanatus.
Hu YW, Liu CY, Du CM, Zhang J, Wu WQ, Gu ZL.
Department of Pharmacology, Medical College of Soochow University, 199 RenAi Road, Suzhou 215123, PR China.
Abstract
AIM OF THE STUDY: Flavonoids extracted from the seeds of Astragalus
complanatus R.Br. reduce the proliferation of many cancer cells. The
present study was carried out to evaluate the effects of these
flavonoids from Astragalus complanatus (FAC) on human hepatocarcinoma
cell viability and apoptosis and to investigate its mechanisms of action
in SMMC-7721 cells.
MATERIALS AND METHODS: Cell viability was measured using the MTT
assay. To detect apoptotic cells, SMMC-7721 cells treated with FAC were
stained with Hoechst 33258 and subjected to agarose gel electrophoresis.
Quantitative detection of apoptotic cells was performed by flow
cytometry. The effects of FAC on apoptosis and cell cycle regulatory
genes and proteins in SMMC-7721 cells were examined using an S series
apoptosis and cell cycle gene array and Western blot analysis.
RESULTS: The growth of SMMC-7721 and HepG2 cells was inhibited by
treatment with FAC. Cell death induced by FAC was characterized by
nuclear condensation and DNA fragmentation. Moreover, the cell cycle was
arrested in the G0/G1 and S phases in FAC-treated SMMC-7721 cells. A
sub-G1 peak with reduced DNA content was also formed. The activity of
caspase-3 was significantly increased following FAC treatment.
Microarray data indicated that the expression levels of 76 genes were
changed in SMMC-7721 cells treated with FAC: 35 genes were up-regulated
and 41 were down-regulated. Western blot analysis showed that caspase-3,
caspase-8, Bax, P21, and P27 protein levels in SMMC-7721 cells were
increased after 48 h of FAC treatment, while cyclinB1, cyclinD1, CDK1,
and CDK4 protein levels were decreased.
CONCLUSIONS: These results suggest that FAC may play an important
role in tumor growth suppression by inducing apoptosis in human
hepatocarcinoma cells via mitochondria-dependent and death
receptor-dependent apoptotic pathways.
J Exp Clin Cancer Res. 2009; 28(1): 51.
Published online Apr 14, 2009. doi: 10.1186/1756-9966-28-51
PMCID: PMC2672058
Amplitude-modulated
electromagnetic fields for the treatment of cancer: Discovery of
tumor-specific frequencies and assessment of a novel therapeutic
approach
Alexandre Barbault,1,2 Frederico P Costa,3 Brad Bottger,4 Reginald F Munden,5 Fin Bomholt,6 Niels Kuster,7 and Boris Pasche
1,81Cabinet Médical, Avenue de la Gare 6, Lausanne, Switzerland
2Rue de Verdun 20, Colmar, France
3Sirio-Libanes Hospital, Oncology Center, São Paulo, Brazil
4Radiology Associates, Danbury Hospital, Danbury, CT, USA
5Department of Radiology, The University of Alabama at Birmingham and UAB Comprehensive Cancer Center, Birmingham, AL, USA
6SPEAG AG, Zurich, Switzerland
7IT’IS, Swiss Federal Institute of Technology, Zurich, Switzerland
8Division of Hematology/Oncology,
Department of Medicine, The University of Alabama at Birmingham and UAB
Comprehensive Cancer Center, Birmingham, AL, USA
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This article has been cited by other articles in PMC.
Abstract
Purpose
Because in vitro studies
suggest that low levels of electromagnetic fields may modify cancer cell
growth, we hypothesized that systemic delivery of a combination of
tumor-specific frequencies may have a therapeutic effect. We undertook
this study to identify tumor-specific frequencies and test the
feasibility of administering such frequencies to patients with advanced
cancer.
Patients and methods
We examined patients with various
types of cancer using a noninvasive biofeedback method to identify
tumor-specific frequencies. We offered compassionate treatment to some
patients with advanced cancer and limited therapeutic options.
Results
We examined a total of 163 patients
with a diagnosis of cancer and identified a total of 1524 frequencies
ranging from 0.1 Hz to 114 kHz. Most frequencies (57–92%) were specific
for a single tumor type. Compassionate treatment with tumor-specific
frequencies was offered to 28 patients. Three patients experienced grade
1 fatigue during or immediately after treatment. There were no NCI
grade 2, 3 or 4 toxicities. Thirteen patients were evaluable for
response. One patient with hormone-refractory breast cancer metastatic
to the adrenal gland and bones had a complete response lasting 11
months. One patient with hormone-refractory breast cancer metastatic to
liver and bones had a partial response lasting 13.5 months. Four
patients had stable disease lasting for +34.1 months (thyroid cancer
metastatic to lung), 5.1 months (non-small cell lung cancer), 4.1 months
(pancreatic cancer metastatic to liver) and 4.0 months (leiomyosarcoma
metastatic to liver).
Conclusion
Cancer-related frequencies appear to
be tumor-specific and treatment with tumor-specific frequencies is
feasible, well tolerated and may have biological efficacy in patients
with advanced cancer.
Trial registration
clinicaltrials.gov identifier NCT00805337
Background
We have previously shown that the
intrabuccal administration of low and safe levels of electromagnetic
fields, amplitude-modulated at a frequency of 42.7 Hz by means of a
battery-powered portable device modifies the electroencephalographic
activity of healthy subjects [1,2], and is associated with subjective and objective relaxation effects [3].
We have also shown that sequential administration of four
insomnia-specific frequencies, including 42.7 Hz, results in a
significant decrease in sleep latency and a significant increase in
total sleep time in patients suffering from chronic insomnia [4,5]. This approach has been termed Low Energy Emission Therapy (LEET)[4].
Dosimetric studies have shown that the amount of electromagnetic fields
delivered to the brain with this approach is 100 to 1000 times lower
than the amount of electromagnetic fields delivered by handheld cellular
phones and does not result in any heating effect within the brain [6].
The U.S. FDA has determined that such a device is not a significant
risk device. A long-term follow-up survey of 807 patients who have
received this therapy in the U.S., Europe and Asia revealed that the
rate of adverse reactions were low and were not associated with
increases in the incidence of malignancy or coronary heart disease [7].
While many discoveries in medicine have evolved from a scientific rationale based on in vitro and in vivo findings,
several seminal discoveries are the results of biological effects first
observed in humans. For example, the development of modern cancer
chemotherapy can be traced directly to the clinical observation that
individuals exposed to mustard gas, a chemical warfare agent, had
profound lymphoid and myeloid suppression. These observations led
Goodman and Gilman to use this agent to treat cancer[8]. Given the advantageous safety profile of athermal, non-ionizing radiofrequency electromagnetic fields[7] and the emerging evidence that low levels of electromagnetic or electric fields may modify the growth of tumor cells [9–11],
we hypothesized that the growth of human tumors might be sensitive to
different but specific modulation frequencies. We tested this hypothesis
through examination of a large number of patients with biopsy-proven
cancer. Using a patient-based biofeedback approach we identified
strikingly similar frequencies among patients with the same type of
cancer and observed that patients with a different type of cancer had
biofeedback responses to different frequencies. These findings provided
strong support for our initial hypothesis. Following identification of
tumor-specific frequencies in 163 patients with a diagnosis of cancer,
we offered compassionate treatment to 28 patients with advanced cancer
and limited palliative therapeutic options. We are reporting the results
of our frequency discovery studies as well as the results of a
feasibility study making use of Low Energy Emission Therapy in the
treatment of cancer.
Methods
Frequency discovery consists in the
measurement of variations in skin electrical resistance, pulse amplitude
and blood pressure. These measurements are conducted while individuals
are exposed to low and safe levels of amplitude-modulated frequencies
emitted by handheld devices. Exposure to these frequencies results in
minimal absorption by the human body, which is well below international
electromagnetic safety limits [12,13].
Patients are lying on their back and are exposed to modulation
frequencies generated by a frequency synthesizer as described below.
Variations in the amplitude of the radial pulse were used as the primary
method for frequency detection. They were defined as an increase in the
amplitude of the pulse for one or more beats during scanning of
frequencies from 0.1 to 114,000 Hz using increments of 100 Hz. Whenever a
change in the amplitude of the pulse is observed, scanning is repeated
using increasingly smaller steps, down to 10-3 Hz.
Frequencies eliciting the best biofeedback responses, defined by the
magnitude of increased amplitude and/or the number of beats with
increased amplitude, were selected as tumor-specific frequencies.
During our initial search for frequencies in patients with
a diagnosis of cancer, we identified frequencies in the 1,000 to 15,000
Hz range. The range of these frequencies was higher than the
frequencies previously identified in patients with insomnia (< 300
Hz). To enable the administration of well defined signals at these
higher frequencies, the signal synthesizer used in the insomnia studies
was redesigned and its accuracy verified at the laboratories of the
Foundation for Research on Information Technology in Society (IT’IS,
Zurich, Switzerland). The Direct Digital Synthesis (DDS) based
synthesizer AD9835 (Analog Devices, Norwood, MA) with a frequency
precision of 10-7 was used for frequency detection in
patients with a diagnosis of cancer. Subsequently, the same frequency
synthesizer was used for treatment administration. The concept of this
novel device is depicted in Figure ?Figure11.
Generation of amplitude-modulated
electromagnetic fields: the device consists of a battery-driven
radiofrequency (RF) electromagnetic field generator connected to a 1.5
meter long 50 Ohm coaxial cable, to the other end of which a
spoon-shaped mouthpiece made of steel is connected with the inner
conductor. The RF source of the device corresponds to a high-level
amplitude-modulated class C amplifier operating at 27.12 MHz. The
modulation frequency can be varied between 0.01 Hz and 150 kHz with a
modulation depth of 85 ± 5%. The output signal is controlled by a
microcontroller AT89S8252 (Atmel, Fribourg, Switzerland), i.e. duration
of a session, sequence of modulation frequencies, and duration of each
sequence are programmed prior to the treatment with a PC connected to
the panel of the device. The RF output is adjusted to 100 mW into a 50
Ohm load using a sinusoidal modulated test signal, which results in an
emitting power identical to that of the device used in the treatment of
insomnia [4,5].
Compassionate treatment
Following a period of search and
discovery of novel tumor-specific frequencies, outpatient treatment of
patients with advanced cancer was initiated in Switzerland and Brazil on
a compassionate basis, free of charge. Patients self-administered
treatment for 60 min, three times a day. Oral informed consent was
provided by seven patients. All other patients signed a written informed
consent approved by a local human subject committee in compliance with
the Helsinki declaration and the protocol was registered,
clinicaltrials.gov identifier # NCT00805337. All patients had
histologically confirmed diagnosis of cancer. Except for patients with a
diagnosis of ovarian cancer, measurable disease was required. For
patients with ovarian cancer, CA 125 level was used as a surrogate
marker of measurable disease and a 50% increase in baseline level
considered evidence of disease progression. All anticancer therapies had
to be discontinued for at least one month prior to treatment
initiation. Other eligibility criteria included an Eastern Cooperative
Group performance status (PS) of 0 to 2 and an estimated life expectancy
of at least 3 months.
Disease assessment
Objective response in patients with
measurable disease was assessed using the Response Evaluation Criteria
in Solid Tumors group classification [14]. Two of us (B.B. and R.F.M.) independently reviewed all imaging studies.
Toxicity assessment
Patients were evaluated for
treatment-related toxicity at a minimum every two months as per the
National Cancer Institute Common Toxicity Criteria version 2.0. The
worst grade of toxicity per patient was recorded.
Results
Patients characteristics
A total of 115 patients were examined in Switzerland, 48 in Brazil (Table ?(Table1).1).
There were 76 females and 87 males. The median age was 59 years (range
19 – 84). The most common tumor types were hepatocellular carcinoma
(46), breast cancer (32), colorectal cancer (19), and prostate cancer
(17).
Table 1
Frequency discovery in 163 patients with a diagnosis of cancer
Compassionate treatment with tumor-specific frequencies was offered to 28 patients (Table ?(Table2).2).
Twenty six patients were treated in Switzerland and two patients were
treated in Brazil. All patients were white, and 63% (n = 17) were
female. Patients ranged in age from 30 to 82 years (median, 61 years)
and 75% (n = 21) had PS of 1 (vs 0 or 2). Seventy-nine percent
(n = 22) of patients had received at least one prior systemic therapy,
57% (n = 17) had received at least two prior systemic therapies (Table ?(Table22).
Table 2
Characteristics of patients treated with amplitude-modulated electromagnetic fields
Once disease progression was observed,
most patients elected to resume or initiate chemotherapy and/or targeted
therapy. Seven (25%) patients requested to continue experimental
treatment in combination with chemotherapy. Continuation of experimental
treatment was allowed if desired by the patient and approved by the
patient’s oncologist.
Discovery of tumor-specific frequencies
The exact duration of each examination
was not recorded but lasted on average three hours. Each patient was
examined an average of 3.3 ± 3.4 times (range 1 – 26). Frequency
discovery was performed in patients with disease progression, stable
disease or partial response. In general, we found more frequencies in
patients with evidence of disease progression and large tumor bulk than
in patients with stable disease, small tumor bulk or evidence of
response. When we restrict the analysis of patients examined in 2006 and
2007, i.e. at a time when we had gathered more than 80% of the common
tumor frequencies, we found that patients with evidence of disease
progression had positive biofeedback responses to 70% or more of the
frequencies previously discovered in patients with the same disease.
Conversely, patients with evidence of response to their current therapy
had biofeedback responses to 20% or less of the frequencies previously
discovered in patients with the same disease. We also observed that
patients examined on repeated occasions developed biofeedback responses
to an increasing number of tumor-specific frequencies over time whenever
there was evidence of disease progression. Whenever feasible, all
frequencies were individually retested at each frequency detection
session. These findings suggest that a larger number of frequencies are
identified at the time of disease progression.
A total of 1524 frequencies ranging from
0.1 to 114 kHz were identified during a total of 467 frequency detection
sessions (Table ?(Table1).1).
The number of frequencies identified in each tumor type ranges from two
for thymoma to 278 for ovarian cancer. Overall, 1183 (77.6%) of these
frequencies were tumor-specific, i.e. they were only identified in
patients with the same tumor type. The proportion of tumor-specific
frequencies ranged from 56.7% for neuroendocrine tumors to 91.7% for
renal cell cancer. A total of 341 (22.4%) frequencies were common to at
least two different tumor types. The number of frequencies identified
was not proportional to either the total number of patients studied or
the number of frequency detection sessions (Table ?(Table11).
Treatment with tumor-specific amplitude-modulated electromagnetic fields
Twenty eight patients received a total
of 278.4 months of experimental treatment. Median treatment duration was
4.1 months per patient; range 1 to +50.5. Patients treated in
Switzerland were re-examined on average every other month for frequency
detection; patients treated in Brazil were only examined once. Novel
frequencies discovered upon re-examination were added to the treatment
program of patients receiving experimental treatment. The first
treatment programs consisted of combinations of less than ten
frequencies while the most recent treatment programs exceed 280
frequencies (Figure ?(Figure22).
Figure 2Compassionate treatment of a 51 year old patient with
ovarian cancer FIGO IIIC with extensive peritoneal carcinomatosis since
October 1997. The patient received paclitaxel and cisplatin from March 97, then docetaxel and carboplatin, doxorubicin, and gemcitabine. …
The evolution of treatment programs through incremental
addition of tumor-specific frequencies is illustrated by the case of a
51 year old woman with ovarian cancer. This patient was diagnosed with
FIGO stage III (G2–G3) ovarian cancer in October 1997 and had received
multiple courses of palliative chemotherapy until 2005. As seen on
Figure ?Figure2,2,
the initial treatment consisting of 15 frequencies did not yield any
response. Upon re-examination, 11 additional frequencies (total of 26)
were added to the treatment program in August 05. Because of disease
progression, treatment with single agent bevacizumab was initiated in
November 05. Interestingly, the CA 125 level had decreased by 200 units
between October and November 2005, prior to the initiation of
bevacizumab. Combined treatment with amplitude-modulated electromagnetic
fields and bevacizumab resulted in a decrease in CA 125 level from 2140
to 540 in May 06. Treatment was supplemented with cyclophosphamide from
March to September 07. The patient was hospitalized with pneumonia and
elected to only receive amplitude-modulated electromagnetic fields since
September 07. As of April 1, 2009 the patient has stable disease and is
asymptomatic. She has been receiving experimental treatment without
interruption for a total of +50.5 months.
This case provides empirical evidence that adding
tumor-specific frequencies may yield disease stabilization in patients
with evidence of disease progression. However, addition of frequencies
over time does not appear to be a requirement for therapeutic efficacy.
This is illustrated by the case of a 59 yo postmenopausal female with
ER/PR positive, ERBB2 negative breast cancer with biopsy confirmed
metastasis to the left ischium and right adrenal gland (Figure ?(Figure3A,3A, Figure ?Figure3C,3C, Figure ?Figure3D).3D).
She had been previously treated with radiation therapy to the left
ischium, had received five different hormonal manipulations (tamoxifen,
anastrozole, exemestane, fulvestran and megestrol). She had also
received capecitabine, which had been discontinued because of
gastrointestinal side effects. The patient was examined only once. In
June 2006, at the time of treatment initiation, the patient complained
of severe left hip pain, which was limiting her mobility despite the
intake of opioids. Within two weeks of experimental treatment initiation
with breast cancer-specific frequencies, the patient reported complete
disappearance of her pain and discontinued the use of pain medications.
She also reported a significant improvement in her overall condition. As
seen on Figure ?Figure3B3B and ?and3E,3E,
PET-CT obtained three months after treatment initiation showed complete
disappearance of the right adrenal and left ischium lesions. The
complete response lasted 11 months. Intriguingly, the patient had
developed intermittent vaginal spotting in the months preceding
experimental treatment initiation. A minimally enhancing uterine lesion
was observed on PET-CT prior to treatment initiation. Upon follow-up,
FDG uptake increased significantly (Figure ?(Figure3B)3B)
and the patient was diagnosed with uterine cancer by hysteroscopy. The
patient underwent hysterectomy, which revealed endometrial
adenocarcinoma. Hence, while treatment with breast cancer specific
frequencies resulted in a complete response, it did not affect the
growth of endometrial adenocarcinoma. This observation suggests that
breast cancer frequencies are tumor-specific as a response of the
metastatic breast cancer was observed while a uterine tumor progressed.
Figure 359 yo postmenopausal female with ER/PR positive, ERBB2
negative breast cancer with biopsy confirmed metastasis to the left
ischium and right adrenal gland. A) Baseline PET MIP image demonstrates metastatic disease of the right adrenal gland (small arrow) …
As seen in Table ?Table3,3,
sixteen patients were evaluable for response by RECIST criteria. A
complete response was observed in a patient with hormone-refractory
breast cancer metastatic to the adrenal gland and bone (Figure ?(Figure3),3),
which lasted 11 months. A partial response was observed in a patient
with hormone-refractory breast cancer metastatic to bone and liver,
which lasted 13.5 months. Five patients had stable disease for +34.1
months (thyroid cancer with biopsy-proven lung metastases), 6.0 months
(mesothelioma metastatic to the abdomen), 5.1 months (non-small cell
lung cancer), and 4.1 months (pancreatic cancer with biopsy-proven liver
metastases). As of April 1, 2009 two patients are still receiving
experimental treatment and four patients are alive.
Table 3
Independent review of best response (N = 16) according to RECIST criteria
Adverse and beneficial reactions
No patients receiving experimental
therapy reported any side effect of significance and no patient
discontinued treatment because of adverse effects. Three patients
(10.7%) reported grade I fatigue after receiving treatment. One patient
(3.6%) reported grade I mucositis after long-term use (26 months) of the
experimental device and concomitant chemotherapy. Two patients with
severe bony pain prior to initiation of experimental treatment reported
significant symptomatic improvement. Both patients had breast cancer
metastatic to the skeleton.
Discussion
In this report we describe the discovery
of tumor-specific amplitude modulation frequencies in patients with a
diagnosis of cancer using noninvasive biodfeedback methods. Our approach
represents a significant departure from the development of novel forms
of chemotherapy and targeted therapy, which commonly rely on in vitro and
animal experiments, followed by phase I studies to assess tolerability.
Given the absence of theoretical health risks related to the
administration of very low level of electromagnetic fields and the
excellent safety profile observed in patients suffering from insomnia
treated for up to several years [7],
our approach was entirely patient-based. This allowed us to examine a
large number of patients with tumor types commonly encountered in
Switzerland and Brazil. It also allowed us to examine the same patients
on multiple occasions, which decreased the variability inherent to a
single frequency detection session.
Examination of patients with cancer led to the
identification of frequencies that were either specific for a given
tumor type or common to two or more tumor types. We observed that most
frequencies were tumor-specific. Indeed, when the analysis of
frequencies is restricted to tumor types analyzed following a minimum of
60 frequency detection sessions (breast cancer, hepatocellular
carcinoma, ovarian cancer and prostate cancer), at least 75% of
frequencies appear to be tumor-specific. Some frequencies such as
1873.477 Hz, 2221.323 Hz, 6350.333 Hz and 10456.383 Hz are common to the
majority of patients with a diagnosis of breast cancer, hepatocellular
carcinoma, prostate cancer and pancreatic cancer. The small number of
frequency detection sessions conducted in patients with thymoma,
leiomyosarcoma, and bladder cancer constitutes a limitation of our study
and an accurate estimate of tumor-specific versus nonspecific
frequencies cannot yet be provided for these tumor types. Only one
patient with thyroid cancer metastatic to the lung was examined 14 times
over the course of the past three years and this led to the discovery
of 112 frequencies, 79.5% of which were thyroid cancer-specific. These
combined findings strongly suggest that many tumor types have a
proportion of tumor-specific frequencies of more than 55%. The high
number of frequencies observed in patients with ovarian cancer may be
due to the various histologies associated with this tumor type.
We observed excellent compliance with this novel treatment
as patients were willing to self-administer experimental treatment
several times a day. The only observed adverse effects in patients
treated with tumor-specific frequencies were grade I fatigue after
treatment (10.6%) and grade I mucositis (3.6%). Fatigue was short-lived
and no patient reported persistent somnolence. Of note, mucositis only
occurred concomitantly with the administration of chemotherapy. The
frequency and severity of adverse effects is analogous to what was
observed in patients treated with insomnia-specific frequencies [5] and confirm the feasibility of this therapeutic approach and its excellent tolerability.
We did not observe any untoward reaction in patient
receiving either chemotherapy or targeted therapy in combination with
amplitude-modulated electromagnetic fields. While these latter findings
are limited to 7 patients, they are consistent with the lack of
theoretical interaction between very low level of electromagnetic fields
and anticancer therapy. Furthermore, one patient received palliative
radiation therapy concomitantly with experimental therapy without any
adverse effects. These findings provide preliminary data suggesting that
amplitude-modulated electromagnetic fields may be added to existing
anticancer therapeutic regimens.
The objective responses observed suggest that
electromagnetic fields amplitude-modulated at tumor-specific frequencies
may have a therapeutic effect. Of the seven patients with metastatic
breast cancer, one had a complete response lasting 11 months, another
one a partial response lasting 13.5 months. These data provide a strong
rationale to further study this novel therapy in breast cancer. The
increased knowledge of tumor-specific frequencies and the preliminary
evidence that additional tumor-specific frequencies may yield a
therapeutic benefit (Figure ?(Figure2)2)
provides a strong rationale for the novel concept that administration
of a large number of tumor-specific frequencies obtained through the
follow-up of numerous patients may result in long-term disease control.
This hypothesis is partially supported by two long-term survivors
reported in this study, a patient with thyroid cancer metastatic to the
lung with stable disease for +34.1 months and a heavily pretreated
patient with ovarian carcinoma and peritoneal carcinomatosis with stable
disease for +50.5 months. Additional support for this hypothesis stems
from the observation that four patients with advanced hepatocellular
carcinoma in a follow-up phase II study by Costa et al had a partial
response, two of them lasting more than 35 months[15].
These exciting results provide hope that this novel therapeutic
approach may yield long-term disease control of advanced cancer.
Kirson et al have recently reported the use of continuous wave (CW) electric fields between 100 KHz to 1 MHz [10,11].
These fields were CW, applied at relative high field strengths but
lower frequencies than the fields used in our study. These frequencies
were found to be effective when applied by insulating external
electrodes to animal cancer models and patients with recurrent
glioblastoma. In contrast to our approach, the electric fields applied
to cancer cells and patients did not include any amplitude modulation.
Hence, it is likely that these two different therapeutic modalities have
different mechanisms of action.
Computer simulation studies have shown
that the specific absorption rate (SAR) in the head resulting from the
use of intrabuccally-administered amplitude-modulated electromagnetic
fields is in the range of 0.1–100 mW/kg[1].
Hence, the SAR outside the head is substantially below 0.1 mW/kg. We
had previously hypothesized that the mechanism of action of
electromagnetic fields amplitude-modulated at insomnia-specific
frequencies was due to modification in ions and neurotransmitters[6], as demonstrated in animal models[16],
as such biological effects had been reported at comparable SARs.
However, this hypothesis does not provide a satisfactory explanation for
the clinical results observed in patients with advanced cancer. First,
the levels of electromagnetic fields delivered to organs such as the
liver, adrenal gland, prostate and hip bones, are substantially lower
than the levels delivered to the head. Second, there is currently no
acceptable rationale for a systemic anti-tumor effect that would involve
subtle changes in neurotransmitters and ions within the central nervous
system. Consequently, we hypothesize that the systemic changes (pulse
amplitude, blood pressure, skin resistivity) observed while patients are
exposed to tumor-specific frequencies are the reflection of a systemic
effect generated by these frequencies. These observations suggest that
electromagnetic fields, which are amplitude-modulated at tumor-specific
frequencies, do not act solely on tumors but may have wide-ranging
effects on tumor host interactions, e.g. immune modulation. The exciting
results from this study provide a strong rationale to study the
mechanism of action of tumor-specific frequencies in vitro and in animal models, which may lead to the discovery of novel pathways controlling cancer growth.
Competing interests
AB and BP have filed a patent
related to the use of electromagnetic fields for the diagnosis and
treatment of cancer. AB and BP are founding members of TheraBionic LLC.
Authors’ contributions
BP and AB conceived and designed
the study. FB and NK designed the device and performed the EM dosimetry.
AB, BP and FC collected and assembled the data. BB and RF independently
reviewed the imaging studies. AB, BP and FC analyzed and interpreted
the data. BP wrote the manuscript. All co-authors read and approved the
final manuscript.
Acknowledgements
The authors would like to thank Al
B. Benson, III, Northwestern University and Leonard B. Saltz, Memorial
Sloan-Kettering Cancer Center for providing insightful comments and
reviewing the manuscript. Neither of them received any compensation for
their work. Presented in part: abstract (ID 14072) ASCO 2007; oral
presentation (29th Annual Meeting of the Bioelectromagnetics
Society, Kanazawa, Japan, 2007). Funding: study funded by AB and BP. The
costs associated with the design and engineering of the devices used in
this study were paid by AB and BP. BB and RM did not receive any
compensation for their independent review of the imaging studies.
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It has been proven that steep pulsed electric field (SPEF) can
directly kill tumor cells and plays an important role in anticancer
treatment. The biorheological mechanisms, however, that destroy tumor
cells are almost unknown. To resolve this issue, here, an SPEF generator
was used to assess the effects of high- and low-dose SPEF on the
proliferation of human hepatoma SMMC-7721 cells by MTT assay, and on the
viscoelasticity, adhesion of SMMC-7721 cells to endothelial cells by
micropipette aspiration technique. Viability and proliferation of
SPEF-treated SMMC-7721 cells were significantly inhibited. Cell cycle
analysis indicated that SPEF arrested the cell cycle progression of
SMMC-7721 cells at the G0/G1 transition to the S-phase. Viscoelastic
data fitted by a standard linear solid model showed that viscoelasticity
of SMMC-7721 cells changed after treatment with SPEF. Moreover, the
adhesive force of low-dose SPEF-treated SMMC-7721 cells to endothelial
cells markedly decreased compared to that of control cells. These
results suggest that the suppressant effects of SPEF on the
proliferation of SMMC-7721 cells appeared to be mediated, at least in
part, through arresting cell cycle progression and altering the
viscoelastic and adhesive properties of the cells, which provides a
novel biorheological mechanism for the antitumor therapy of SPEF.
The Effect of Intense Subnanosecond Electrical Pulses on Biological Cells
Schoenbach, K.H. Shu Xiao Joshi, R.P. Camp, J.T. Heeren, T. Kolb, J.F. Beebe, S.J.
Old Dominion Univ., Norfolk;
This paper appears in: Plasma Science, IEEE Transactions on
Publication Date: April 2008
Volume: 36, Issue: 2, Part 1
On page(s): 414-422
Location: Eindhoven, Netherlands,
ISSN: 0093-3813
INSPEC Accession Number: 9921271
Digital Object Identifier: 10.1109/TPS.2008.918786
Current Version Published: 2008-04-08
AbstractNanosecond electrical pulses
have been successfully used to treat melanoma tumors by using needle
arrays as pulse delivery systems. Reducing the pulse duration of intense
electric field pulses from nanoseconds into the subnanosecond range
will allow us to use wideband antennas to deliver the electromagnetic
fields into tissue with a spatial resolution in the centimeter range. To
explore the biological effect of intense subnanosecond pulses, we have
developed a generator that provides voltage pulses of 160 kV amplitude,
200 ps rise time, and 800 ps pulse width. The pulses are delivered to a
cylindrical Teflon chamber with polished flat electrodes at either end.
The distance between the electrodes is variable and allows us to
generate electric fields of up to 1 MV/cm in cell suspensions. The
pulses have been applied to B16 (murine melanoma) cells, and the plasma
membrane integrity was studied by means of trypan blue exclusion. For
pulse amplitudes of 550 kV/cm, approximately 50% of the cells took up
trypan blue right after pulsing, whereas only 20% were taking it up
after 1 h. This indicates that the plasma membrane in a majority of the
cells affected by the pulses recovers with a time constant of about 1 h.
The cells that show trypan blue uptake after this time suffer cell
death through apoptosis. Evaluation of the experimental results and
molecular dynamics modeling results indicate that with a pulse duration
of 800 ps, membrane charging and nanopore formation are the dominant
bioelectric effects on B16 cells. This information has been used in a
continuum model to estimate the increase in membrane permeability and,
consequently, the increase in pore size caused by repetitive pulsing.
Conf Proc IEEE Eng Med Biol Soc. 2008;2008:1044-7.
Experiment and mechanism research of SKOV3 cancer cell apoptosis induced by nanosecond pulsed electric field.
Yao C, Mi Y, Hu X, Li C, Sun C, Tang J, Wu X.
State Key Laboratory of Power Transmission Equipment & System
Security and New Technology, Chongqing University, Chongqing 400044,
China.
Abstract
This paper studies the apoptosis of human ovarian carcinoma cell Line
(SKOV3) induced by the nanosecond pulsed electric field (10kV/cm,
100ns, 1 Hz) and its effect on intracellular calcium concentration
([Ca2+]i). These cells were doubly marked by Annexin V-FITC/PI, and the
apoptosis rate was analyzed with flow cytometry. After AO/EB staining
the morphological changes were observed under fluorescent microscope,
and their ultrastructural changes were observed under scanning electron
microscope (SEM). With Fluo-3/AM as calcium fluorescent marker, laser
scanning confocal microscope (LSCM) was used to detect the effect of
nsPEF on [Ca2+]i and the source of Ca2+. The results showed that the
early apoptosis rate of the treatment group was (22.21+/-2.71)%,
significantly higher than that of the control group (3.04+/-0.44)%
(P<0.01). The typical features of apoptotic cell have been observed
by fluorescent microscope and SEM. It is proved that nsPEF can induce
apoptosis of SKOV3 cells and result in distinct increase in [Ca2+]i
(P0.01), which was independent of extracellular calcium concentration
(P>0.05). Since nsPEF can penetrate cell membrane due to its high
frequency components, one of the mechanisms of nsPEF-induced apoptosis
may be that activating intracellular calcium stores can increase the
[Ca2+]i, and consequently, the apoptotic signal pathway can be induced.
Apoptosis. 2007 Sep;12(9):1721-31.
Nanosecond pulsed electric fields induce apoptosis in p53-wildtype and p53-null HCT116 colon carcinoma cells.
Hall EH, Schoenbach KH, Beebe SJ.
Center for Pediatric Research, Children’s Hospital of the King’s
Daughters, Department of Physiological Sciences, Eastern Virginia
Medical School, PO Box 1980, Norfolk, VA 23501-1980, USA.
Abstract
Non-ionizing radiation produced by nanosecond pulsed electric fields
(nsPEFs) is an alternative to ionizing radiation for cancer treatment.
NsPEFs are high power, low energy (non-thermal) pulses that, unlike
plasma membrane electroporation, modulate intracellular structures and
functions. To determine functions for p53 in nsPEF-induced apoptosis,
HCT116p53(+/+) and HCT116p53(-/-) colon carcinoma cells were exposed to
multiple pulses of 60 kV/cm with either 60 ns or 300 ns durations and
analyzed for apoptotic markers. Several apoptosis markers were observed
including cell shrinkage and increased percentages of cells positive for
cytochrome c, active caspases, fragmented DNA, and Bax, but not Bcl-2.
Unlike nsPEF-induced apoptosis in Jurkat cells (Beebe et al. 2003a)
active caspases were observed before increases in cytochrome c, which
occurred in the presence and absence of Bax. Cell shrinkage occurred
only in cells with increased levels of Bax or cytochrome c. NsPEFs
induced apoptosis equally in HCT116p53(+/+) and HCT116p53(-/-) cells.
These results demonstrate that non-ionizing radiation produced by nsPEFs
can act as a non-ligand agonist with therapeutic potential to induce
apoptosis utilizing mitochondrial-independent mechanisms in HCT116 cells
that lead to caspase activation and cell death in the presence or
absence of p-53 and Bax.
Hell J Nucl Med. 2007 May-Aug;10(2):95-101.
Anticancer effects on leiomyosarcoma-bearing Wistar rats after electromagnetic radiation of resonant radiofrequencies.
Avdikos A, Karkabounas S, Metsios A, Kostoula O, Havelas K, Binolis J, Verginadis I, Hatziaivazis G, Simos I, Evangelou A.
Source
Laboratory of Physiology, Unit of Environmental Physiology, Faculty of Medicine, University of Ioannina, Greece.
Abstract
In the present study, the effects of a resonant low intensity static
electromagnetic field (EMF), causing no thermal effects, on Wistar rats
have been investigated. Sarcoma cell lines were isolated from
leiomyosarcoma tumors induced in Wistar rats by the subcutaneous (s.c)
injection of 3,4-benzopyrene. Furthermore, smooth muscle cells (SMC)
were isolated from the aorta of Wistar rats and cultivated. Either
leiomyosarcoma cells (LSC) or SMC were used to record a number of
characteristic resonant radiofrequencies, in order to determine the
specific electromagnetic fingerprint spectrum for each cell line. These
spectra were used to compose an appropriate algorithm, which transforms
the recorded radiofrequencies to emitted ones. The isolated LSC were
cultured and then exposed to a resonant low intensity radiofrequency EMF
(RF-EMF), at frequencies between 10 kHz to 120 kHz of the radiowave
spectrum. The exposure lasted 45 consecutive minutes daily, for two
consecutive days. Three months old female Wistar rats were inoculated
with exposed and non-exposed to EMF LSC (4 x 10(6) LCS for animal).
Inoculated with non-exposed to EMF cells animals were then randomly
separated into three Groups. The first Group was sham exposed to the
resonant EMF (control Group-CG), the second Group after the inoculation
of LSC and appearance of a palpable tumor mass, was exposed to a
non-resonant EMF radiation pattern, for 5 h per day till death of all
animals (experimental control Group-ECG). The third Group of animals
after inoculation of LSC and the appearance of a palpable tumor mass,
was exposed to the resonant EMF radiation for 5 h per day, for a maximum
of 60 days (experimental Group-I, EG-I). A fourth Group of animals was
inoculated with LSC exposed to EMF irradiation and were not further
exposed to irradiation (experimental Group-II, EG-II). Tumor induction
was 100% in all Groups studied and all tumors were histologically
identified as leiomyosarcomas. In the case of the EG-I, a number of
tumors were completely regretted (final tumor induction: 66%). Both
Groups of animals inoculated with exposed or non-exposed to the EMF LSC,
(EG-I and EG-II, respectively) demonstrated a significant prolongation
of the survival time and a lower tumor growth rate, in comparison to the
control Group (CG) and the experimental control Group (ECG). However,
the survival time of EG-I animals was found to be significantly longer
and tumor growth rate significantly lower compared to EG-II animals. In
conclusion, our results indicate a specific anticancer effect of
resonant EMF irradiation. These results may possibly be attributed to
(a) the duration of exposure of LSC and (b) the exposure of the entire
animal to this irradiation.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2007 Feb;24(1):230-4.
Biological effects and their applications in medicine of pulsed electric fields.
[Article in Chinese]
Huang H, Song G, Wang G, Sun C.
Key Laboratory for Biomnechanics & Tissue Engineering of the
State Ministry of Education, College of Bioengineering, Chongqing
University, Chongqing 400044, China.
Abstract
Pulsed electric fields can induce various kinds of biological effects
that are essentially different from the normal electric fields,
especially the interactions of Nanosecond Pulsed electric field (nsPEF)
with cells. The biological effects of different pulsed electric fields
on cell membranes, cytoplasmic matrixes, cell growth are introduced in
this paper. Based on these effects, some applications of pulsed electric
fields in cancer therapy, gene therapy, and delivery of drugs are
reviewed in details.
Biochem Biophys Res Commun. 2006 May 5;343(2):351-60. Epub 2006 Mar 10.
Nanosecond pulsed electric fields cause melanomas to self-destruct.
Nuccitelli R, Pliquett U, Chen X, Ford W, James Swanson R, Beebe SJ, Kolb JF, Schoenbach KH.
Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA. yaochenguo@cqu.edu.cn
Abstract
We have discovered a new, drug-free therapy for treating solid skin
tumors. Pulsed electric fields greater than 20 kV/cm with rise times of
30 ns and durations of 300 ns penetrate into the interior of tumor cells
and cause tumor cell nuclei to rapidly shrink and tumor blood flow to
stop. Melanomas shrink by 90% within two weeks following a cumulative
field exposure time of 120 micros. A second treatment at this time can
result in complete remission. This new technique provides a highly
localized targeting of tumor cells with only minor effects on overlying
skin. Each pulse deposits 0.2 J and 100 pulses increase the temperature
of the treated region by only 3 degrees C, ten degrees lower than the
minimum temperature for hyperthermia effects.
Bioelectromagnetics. 2006 May;27(4):258-64.
Effect of millimeter wave irradiation on tumor metastasis.
Logani MK, Szabo I, Makar V, Bhanushali A, Alekseev S, Ziskin MC.
Richard J. Fox Center for Biomedical Physics, Temple University School of Medicine, Philadelphia, PA 19140, USA. mlogani@temple.edu
Abstract
One of the major side effects of chemotherapy in cancer treatment is
that it can enhance tumor metastasis due to suppression of natural
killer (NK) cell activity. The present study was undertaken to examine
whether millimeter electromagnetic waves (MMWs) irradiation (42.2 GHz)
can inhibit tumor metastasis enhanced by cyclophosphamide (CPA), an
anticancer drug. MMWs were produced with a Russian-made YAV-1 generator.
Peak SAR and incident power density were measured as 730 +/- 100 W/kg
and 36.5 +/- 5 mW/cm(2), respectively. Tumor metastasis was evaluated in
C57BL/6 mice, an experimental murine model commonly used for metastatic
melanoma. The animals were divided into 5 groups, 10 animals per group.
The first group was not given any treatment. The second group was
irradiated on the nasal area with MMWs for 30 min. The third group
served as a sham control for group 2. The fourth group was given CPA
(150 mg/kg body weight, ip) before irradiation. The fifth group served
as a sham control for group 4. On day 2, all animals were injected,
through a tail vein, with B16F10 melanoma cells, a tumor cell line
syngeneic to C57BL/6 mice. Tumor colonies in lungs were counted 2 weeks
following inoculation. CPA caused a marked enhancement in tumor
metastases (fivefold), which was significantly reduced when CPA-treated
animals were irradiated with MMWs. Millimeter waves also increased NK
cell activity suppressed by CPA, suggesting that a reduction in tumor
metastasis by MMWs is mediated through activation of NK cells.
Bioelectromagnetics. 2006 Apr;27(3):226-32.
Effect of extremely low frequency electromagnetic fields (ELF-EMF) on Kaposi’s sarcoma-associated herpes virus in BCBL-1 cells.
Pica F, Serafino A, Divizia M, Donia D, Fraschetti M, Sinibaldi-Salimei P, Giganti MG, Volpi A.
Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, Rome, Italy.
Association between extremely low frequency electromagnetic fields
(ELF-EMF) and human cancers is controversial, and few studies have been
conducted on their influence on oncogenic viruses. We studied the
effects of 1 mT, 50 Hz sine waves, applied for 24-72 h, on Kaposi’s
sarcoma (KS)-associated herpesvirus (KSHV or HHV-8) in BCBL-1, a
latently infected primary effusion lymphoma (PEL) cell line. ELF-EMF
exposure did not affect the growth and viability of BCBL-1 cells, either
stimulated or not with TPA. The total amount of KSHV DNA detected in
ELF-EMF exposed cultures not stimulated with TPA did not differ from
that of the unexposed controls (P = ns). However, in the presence of TPA
stimulation, total KSHV DNA content was found higher in ELF-EMF exposed
than in control BCBL-1 cultures (P = .024) at 72 h exposure, but not
earlier. Viral DNA increase significantly correlated with increased mean
fluorescence intensity/cell for the lytic antigen gp K8.1A/B (P <
.01), but not with percentage of gp K8.1A/B-positive cells or of cells
containing virions. Viral progeny produced under ELF-EMF exposure
consisted mainly of defective viral particles.
Conf Proc IEEE Eng Med Biol Soc. 2006;1:6370-2.
Outlook for the use of focused shock waves and pulsed electric fields in the complex treatment of malignant neoplasms.
The experimental studies the synchronous action of electric field
microsecond range with amplitude within the range of 1-7 kV/sm and shock
waves with pressure before 100 MPa on cells membrane permeability of
the mouse’s ascitic tumors in vitro have shown the intensification the
efficiency of the forming the irreversible pores under synchronous
action. Thereby, enabling the electric field in the compression phase of
shock wave pulse which can essentially reduce the electric field
intensity required for breakdown cell membrane. In usual condition at
amplitude of electric field, specified above, electric breakdown
membrane carries basically reversible nature. At the same time in the
pressure field tension phase of shock-wave pulse reversible pores,
created by electric field, can grow before sizes, under which wholeness
membrane is not restored. Under simultaneous action on cellular
suspension the shock wave and electric field with moderate intensity
cells survival is reduced in 5 once in contrast with occuring at
different time’s action, and in 10 once in contrast with checking. The
most sensitive to influence by under study fields are cells in phase of
the syntheses DNA, preparation to fission and in phase of the mitosis.
Thereby, continuation of the studies on use synchronous action shock
waves and pulsed electric fields in complex treatment of the tumors
introduces perspectiv
Bioelectromagnetics. 2006 Jan;27(1):64-72.
Effects of pulsed magnetic stimulation on tumor development and immune functions in mice.
Yamaguchi S, Ogiue-Ikeda M, Sekino M, Ueno S.
Department of Biomedical Engineering, Graduate School of Medicine, University of Tokyo, Japan.
We investigated the effects of pulsed magnetic stimulation on tumor
development processes and immune functions in mice. A circular coil
(inner diameter = 15 mm, outer diameter = 75 mm) was used in the
experiments. Stimulus conditions were pulse width = 238 micros, peak
magnetic field = 0.25 T (at the center of the coil), frequency = 25
pulses/s, 1,000 pulses/sample/day and magnetically induced eddy currents
in mice = 0.79-1.54 A/m(2). In an animal study, B16-BL6 melanoma model
mice were exposed to the pulsed magnetic stimulation for 16 days from
the day of injection of cancer cells. A tumor growth study revealed a
significant tumor weight decrease in the stimulated group (54% of the
sham group). In a cellular study, B16-BL6 cells were also exposed to the
magnetic field (1,000 pulses/sample, and eddy currents at the bottom of
the dish = 2.36-2.90 A/m(2)); however, the magnetically induced eddy
currents had no effect on cell viabilities. Cytokine production in mouse
spleens was measured to analyze the immunomodulatory effect after the
pulsed magnetic stimulation. tumor necrosis factor (TNF-alpha)
production in mouse spleens was significantly activated after the
exposure of the stimulus condition described above. These results showed
the first evidence of the anti-tumor effect and immunomodulatory
effects brought about by the application of repetitive magnetic
stimulation and also suggested the possible relationship between
anti-tumor effects and the increase of TNF-alpha levels caused by pulsed
magnetic stimulation.
Clin Cancer Res. 2005 Oct 1;11(19 Pt 2):7093s-7103s.
Application of high amplitude alternating magnetic fields for heat induction of nanoparticles localized in cancer.
OBJECTIVE: Magnetic nanoparticles conjugated to a monoclonal antibody
can be i.v. injected to target cancer tissue and will rapidly heat when
activated by an external alternating magnetic field (AMF). The result
is necrosis of the microenvironment provided the concentration of
particles and AMF amplitude are sufficient. High-amplitude AMF causes
nonspecific heating in tissues through induced eddy currents, which must
be minimized. In this study, application of high-amplitude, confined,
pulsed AMF to a mouse model is explored with the goal to provide data
for a concomitant efficacy study of heating i.v. injected magnetic
nanoparticles.
METHODS: Thirty-seven female BALB/c athymic nude mice (5-8 weeks)
were exposed to an AMF with frequency of 153 kHz, and amplitude
(400-1,300 Oe), duration (1-20 minutes), duty (15-100%), and pulse ON
time (2-1,200 seconds). Mice were placed in a water-cooled four-turn
helical induction coil. Two additional mice, used as controls, were
placed in the coil but received no AMF exposure. Tissue and core
temperatures as the response were measured in situ and recorded at
1-second intervals.
RESULTS: No adverse effects were observed for AMF amplitudes of <
or = 700 Oe, even at continuous power application (100% duty) for up to
20 minutes. Mice exposed to AMF amplitudes in excess of 950 Oe
experienced morbidity and injury when the duty exceeded 50%.
CONCLUSION: High-amplitude AMF (up to 1,300 Oe) was well tolerated
provided the duty was adjusted to dissipate heat. Results presented
suggest that further tissue temperature regulation can be achieved with
suitable variations of pulse width for a given amplitude and duty
combination. These results suggest that it is possible to apply
high-amplitude AMF (> 500 Oe) with pulsing for a time sufficient to
treat cancer tissue in which magnetic nanoparticles have been embedded.
Anticancer Res. 2005 Mar-Apr;25(2A):1023-8.
Frequency and irradiation time-dependant antiproliferative effect of
low-power millimeter waves on RPMI 7932 human melanoma cell line.
Beneduci A, Chidichimo G, De Rose R, Filippelli L, Straface SV, Venuta S.
Department of Chemistry, University of Calabria, 87036 Arcavacata di Rende (CS), Italy. beneduci@unical.it
Abstract
The biological effects produced by low power millimeter waves (MMW)
were studied on the RPMI 7932 human melanoma cell line. Three different
frequency-type irradiation modes were used: the 53.57-78.33 GHz
wide-band frequency range, the 51.05 GHz and the 65.00 GHz monochromatic
frequencies. In all three irradiation conditions, the radiation energy
was low enough not to increase the temperature of the cellular samples.
Three hours of radiation treatment, applied every day to the melanoma
cell samples, were performed at each frequency exposure condition. The
wide-band irradiation treatment effectively inhibited cell growth, while
both the monochromatic irradiation treatments did not affect the growth
trend of RPMI 7932 cells. A light microscopy analysis revealed that the
low-intensity wide-band millimeter radiation induced significant
morphological alterations on these cells. Furthermore, a histochemical
study revealed the low proliferative state of the irradiated cells. This
work provides further evidence of the antiproliferative effects on
tumor cells induced by low power MMW in the 50-80 GHz frequency range of
the electromagnetic spectrum.
Bioelectromagnetics. 2005 Jan;26(1):10-9.
Effect of millimeter waves on natural killer cell activation.
Makar VR, Logani MK, Bhanushali A, Kataoka M, Ziskin MC.
Richard J Fox Center for Biomedical Physics, Temple University School of Medicine, Philadelphia, PA 19140, USA.
Abstract
Millimeter wave therapy (MMWT) is being widely used for the treatment
of many diseases in Russia and other East European countries. MMWT has
been reported to reduce the toxic effects of chemotherapy on the immune
system. The present study was undertaken to investigate whether
millimeter waves (MMWs) can modulate the effect of cyclophosphamide
(CPA), an anticancer drug, on natural killer (NK) cell activity. NK
cells play an important role in the antitumor response. MMWs were
produced with a Russian-made YAV-1 generator. The device produced
modulated 42.2 +/- 0.2 GHz radiation through a 10 x 20 mm rectangular
output horn. Mice, restrained in plastic tubes, were irradiated on the
nasal area. Peak SAR at the skin surface and peak incident power density
were measured as 622 +/- 100 W/kg and 31 +/- 5 mW/cm2, respectively.
The maximum temperature elevation, measured at the end of 30 min, was 1
degrees C. The animals, restrained in plastic tubes, were irradiated on
the nasal area. CPA injection (100 mg/kg) was given intraperitoneally on
the second day of 3-days exposure to MMWs. All the irradiation
procedures were performed in a blinded manner. NK cell activation and
cytotoxicity were measured after 2, 5, and 7 days following CPA
injection. Flow cytometry of NK cells showed that CPA treatment caused a
marked enhancement in NK cell activation. The level of CD69 expression,
which represents a functional triggering molecule on activated NK
cells, was increased in the CPA group at all the time points tested as
compared to untreated mice. However, the most enhancement in CD69
expression was observed on day 7. A significant increase in TNF-alpha
level was also observed on day 7 following CPA administration. On the
other hand, CPA caused a suppression of the cytolytic activity of NK
cells. MMW irradiation of the CPA treated groups resulted in further
enhancement of CD69 expression on NK cells, as well as in production of
TNF-alpha. Furthermore, MMW irradiation restored CPA induced suppression
of the cytolytic activity of NK cells. Our results show that MMW
irradiation at 42.2 GHz can up-regulate NK cell functions.
Bioelectromagnetics. 2004 Oct;25(7):516-23.
Combined millimeter wave and cyclophosphamide therapy of an experimental murine melanoma.
Logani MK, Bhanushali A, Anga A, Majmundar A, Szabo I, Ziskin MC.
Richard J. Fox Center for Biomedical Physics, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA.
The objective of the present studies was to investigate whether
millimeter wave (MMW) therapy can increase the efficacy of
cyclophosphamide (CPA), a commonly used anti-cancer drug. The effect of
combined MMW-CPA treatment on melanoma growth was compared to CPA
treatment alone in a murine model. MMWs were produced with a Russian
made YAV-1 generator. The device produced 42.2 +/- 0.2 GHz modulated
wave radiation through a 10 x 20 mm rectangular output horn. The
animals, SKH-1 hairless female mice, were irradiated on the nasal area.
Peak SAR and incident power density were measured as 730 +/- 100 W/kg
and 36.5 +/- 5 mW/cm2, respectively. The maximum skin surface
temperature elevation measured at the end of 30 min irradiation was 1.5
degrees C. B16F10 melanoma cells (0.2 x 10(6)) were implanted
subcutaneously into the left flank of mice on day 1 of the experiment.
On days 4-8, CPA was administered intraperitoneally (30 mg/kg/day). MMW
irradiation was applied concurrently with, prior to or following CPA
administration. A significant reduction (P < .05) in tumor growth was
observed with CPA treatment, but MMW irradiation did not provide
additional therapeutic benefit as compared to CPA alone. Similar results
were obtained when MMW irradiation was applied both prior to and
following CPA treatment.
Biofizika. 2004 May-Jun;49(3):545-50.
A comparison of the effects of millimeter and centimeter waves on tumor necrosis factor production in mouse cells.
The effects of millimeter (40 GHz) and centimeter (8.15-18.00 GHz)
low-intensity waves on the production of tumor necrosis factor (TNE) in
macrophages and lymphocytes from exposed mice as well as in exposed
isolated cells were compared. It was found that the dynamics of TNF
secretory activity of cells varies depending on the frequency and
duration of exposure. The application of millimeter waves induced a
nonmonotonous course of the dose-effect curve for TNF changes in
macrophages and splenocytes. Alternately, a stimulation and a decrease
in TNF production were observed following the application of millimeter
waves. On the contrary, centimeter waves provoked an activation in
cytokine production. It is proposed that, in contrast to millimeter
waves, the single application of centimeter waves to animals (within 2
to 96 h) or isolated cells (within 0.5 to 2.5 h) induced a much more
substantial stimulation of immunity.
Bioelectromagnetics. 2004 Oct;25(7):503-7.
Differences in lethality between cancer cells and human lymphocytes caused by LF-electromagnetic fields.
Radeva M, Berg H.
Labor Bioelectrochemistry (Campus Beutenberg, Jena) of the Saxonian Academy of Sciences, Leipzig, Germany.
Abstract
The lethal response of cultured cancer cells lines K-562, U-937,
DG-75, and HL-60 were measured directly after a 4 h exposure to a
pulsating electromagnetic field (PEMF, sinusoidal wave form, 35 mT peak,
50 Hz) [Traitcheva et al. (2003): Bioelectromagnetics 24:148-158] and
24 h later, to determine the post-exposure effect. The results were
found to depend on the medium, pH value, conductivity, and temperature.
From these experiments, suitable conditions were chosen to compare the
vitality between K-562 cells and normal human lymphocytes after PEMF
treatment and photodynamic action. Both agents enhance necrosis
synergistically for diseased as well as for healthy cells, but the
lymphocytes are more resistant. The efficacy of PEMF on the destruction
of cancer cells is further increased by heating (hyperthermia) of the
suspension up to 44 degrees C or by lowering the pH-value (hyperacidity)
to pH 6.4. Similar apoptosis and necrosis can be obtained using
moderate magnetic fields (B < or = 15 mT 50/60 Hz), but this requires
longer treatment of at least over a week. PEMF application combined
with anticancer drugs and photodynamic therapy will be very effective.
Bioelectromagnetics. 2004 Sep;25(6):466-73.
Millimeter wave-induced suppression of B16 F10 melanoma growth in mice: involvement of endogenous opioids.
Radzievsky AA, Gordiienko OV, Szabo I, Alekseev SI, Ziskin MC.
Center for Biomedical Physics, Temple University Medical School, Philadelphia, Pennsylvania 19140, USA. aradziev@temple.edu
Abstract
Millimeter wave treatment (MMWT) is widely used in Eastern European
countries, but is virtually unknown in Western medicine. Among reported
MMWT effects is suppression of tumor growth. The main aim of the present
“blind” and dosimetrically controlled experiments was to evaluate
quantitatively the ability of MMWT to influence tumor growth and to
assess whether endogenous opioids are involved. The murine experimental
model of B16 F10 melanoma subcutaneous growth was used. MMWT
characteristics were: frequency, 61.22 GHz; average incident power
density, 13.3 x 10(-3) W/cm2; single exposure duration, 15 min; and
exposure area, nose. Naloxone (1 mg/kg, intraperitoneally, 30 min prior
to MMWT) was used as a nonspecific blocker of opioid receptors. Five
daily MMW exposures, if applied starting at the fifth day following B16
melanoma cell injection, suppressed subcutaneous tumor growth.
Pretreatment with naloxone completely abolished the MMWT-induced
suppression of melanoma growth. The same course of 5 MMW treatments, if
started on day 1 or day 10 following tumor inoculations, was
ineffective. We concluded that MMWT has an anticancer therapeutic
potential and that endogenous opioids are involved in MMWT-induced
suppression of melanoma growth in mice. However, appropriate indications
and contraindications have to be developed experimentally before
recommending MMWT for clinical usage.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2004 Aug;21(4):546-8.
Effects of steep pulsed electric fields on cancer cell proliferation and cell cycle.
[Article in Chinese]
Yao C, Sun C, Mi Y, Xiong L, Hu L, Hu Y.
Key Lab of High Voltage Engineering and Electrical New Technology,
Ministry of Education, Chongqing University, Chongqing 400044, China.
Abstract
To assess study the cytocidal and inhibitory effects of steep pulsed
electric fields (SPEFs) on ovarian cancer cell line SKOV3, the cancer
cell suspension was treated by SPEFs with different parameters
(frequency, pulse duration, peak value of voltage). Viability rate and
growth curves of two test groups (high dosage and low dosage of SPEFs)
and one control group were also measured. The DNA contents and cell
cycle were analyzed by flow cytometry (FCM). Different dosing levels of
SPEFs exerted obviously different effects on cancer cell viability. With
the enhancement of each pulse parameter, the viability rate was
promoted and the inhibitory effect on the proliferation of treated cells
was more evident. The cells exposed to SPEFs grew slower than the
control. The ratio of S+G2/M phase cells was decreased, which restrained
the DNA synthesis and division, but the ratio of G0/G1 phase cells was
increased in the treated groups. It was also indicated that the SPEFs
blocked the cell transition from G0/G1 phase to S+G2/M phase. There was a
significant difference in cell cycle between treated group and control
group (P<0.01). Lethal effects of SPEFs were represented by
inhibiting the cancer cell proliferation at the cell level and by
influencing the cell cycle at the DNA level.
Physiol Meas. 2004 Aug;25(4):1077-93.
Nanosecond pulsed electric fields modulate cell function through intracellular signal transduction mechanisms.
Beebe SJ, Blackmore PF, White J, Joshi RP, Schoenbach KH.
Center for Pediatric Research, Eastern Virginia Medical School, Children’s Hospital for The King’s Daughters, Norfolk, VA, USA. sbeebe@chkd.com
These studies describe the effects of nanosecond (10-300 ns) pulsed
electric fields (nsPEF) on mammalian cell structure and function. As the
pulse durations decrease, effects on the plasma membrane (PM) decrease
and effects on intracellular signal transduction mechanisms increase.
When nsPEF-induced PM electroporation effects occur, they are distinct
from classical PM electroporation effects, suggesting unique,
nsPEF-induced PM modulations. In HL-60 cells, nsPEF that are well below
the threshold for PM electroporation and apoptosis induction induce
effects that are similar to purinergic agonistmediated calcium release
from intracellular stores, which secondarily initiate capacitive calcium
influx through store-operated calcium channels in the PM. NsPEF with
durations and electric field intensities that do or do not cause PM
electroporation, induce apoptosis in mammalian cells with a
well-characterized phenotype typified by externalization of
phosphatidylserine on the outer PM and activation of caspase proteases.
Treatment of mouse fibrosarcoma tumors with nsPEF also results in
apoptosis induction. When Jurkat cells were transfected by
electroporation and then treated with nsPEF, green fluorescent protein
expression was enhanced compared to electroporation alone. The results
indicate that nsPEF activate intracellular mechanisms that can determine
cell function and fate, providing an important new tool for probing
signal transduction mechanisms that modulate cell structure and function
and for potential therapeutic applications for cancer and gene therapy.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2004 Jun;21(3):433-5.
Effect of steep pulsed electric fields on survival of tumour-bearing mice.
[Article in Chinese]
Yao C, Sun C, Xiong L, Mi Y, Liao R, Hu L, Hu Y.
College of Electrical Engineering, Chongqing University, Chongqing, 400044, China.
To investigate the lethal effect of steep pulsed electric fields
(SPEFs) on cancer cells and the life-prolonging effect of SPEFs on the
survival of tumour-bearing mice, this study was carried out with the use
of SPEFs to treat 40 BALB/C mice inoculated by cervical cancer. The
lethal effect on cancer cells and the life-prolonging effect on
tumour-bearing mice were examined and compared between the experiment
group and control group. The survival periods of the experiment group
and control group were 52.05 days and 33.03 days, respectively. There
was a significant difference in survival curve between the two groups.
The results confirmed the inhibitiory effect and lethal effect of SPEFs
on cancer cells. SPEFs can prolong the survival period of tumour-bearing
mice.
Ann Biomed Eng. 2003 Jan;31(1):80-90.
Viability of cancer cells exposed to pulsed electric fields: the role of pulse charge.
Krassowska W, Nanda GS, Austin MB, Dev SB, Rabussay DP.
Department of Biomedical Engineering, Duke University, Durham, NC 27708-0281, USA. wanda.krassowska@duke.edu
The goal of this study was to collect a comprehensive set of data
that related lethal effects of electric fields to the duration of the
pulse. Electric pulses of different strengths and durations were applied
to a suspension of HEp-2 cells (epidermoid carcinoma of the human
larynx) using a six-needle electrode array connected through an
autoswitcher to a square wave generator. Pulse durations varied from 50
micros to 16 ms and the ranges of electric field were adjusted for each
duration to capture cell viabilities between 0% and 100%. After
pulsation, cells were incubated for 44 h at 37 degrees C, and their
viability was measured spectrophotometrically using an XTT assay. For
each pulse duration (d), viability data were used to determine the
electric field that killed half of the cells (E50). When plotted on
logarithmic axes, E50 vs. d was a straight line, leading to a hyperbolic
relationship: E50=const/d. This relationship suggests that the total
charge delivered by the pulse is the decisive factor in killing HEp-2
cells.
Vopr Onkol. 2003;49(6):748-51.
Experience with turbulent magnetic field as a component of breast cancer therapy.
N.N. Blokhin Center for Oncology Research, Russian Academy of Medical Sciences, Zdorovje Research Center, Moscow.
No adverse side-effects were reported in an investigation of the
antitumor effect of turbulent magnetic field (TMF) carried out as a
component of preoperative chemoradiotherapy for breast cancer at the
Center’s Clinic. The study group included 114 patients with locally
advanced tumors(T3, N1-N3, M0). According to the clinical,
roentgenological and histological evidence on the end-results, the
procedure was highly effective. Also, it was followed by shorter and
less extensive postoperative lymphorrhea.
Bioelectromagnetics. 2003 Feb;24(2):148-50.
ELF fields and photooxidation yielding lethal effects on cancer cells.
Traitcheva N, Angelova P, Radeva M, Berg H.
Laboratory of Bioelectrochemistry, Institute of Virology, FSU, Jena, Germany.
Abstract
The lethal effect on human cancer cells was studied under three types
of treatment: A) an ELF pulsed sinusoidal of 50 Hz electromagnetic
field (PEMF) with amplitudes between 10 and 55 mT; B) the field and a
cytostatic agent (actinomycin-C); and C) the field, the cytostatic
agent, which has a photodynamic effect, and exposure to a halogen lamp.
The results show a decreasing vitality of human K-562 and U-937 cancer
cells in suspension with each additional treatment. Combination with
other parameters as hyperthermia and/or hyperacidity could yield high
killing rates by this noninvasive method.
Technol Cancer Res Treat. 2002 Feb;1(1):71-82.
Enhancing the effectiveness of drug-based cancer therapy by electroporation (electropermeabilization).
Rabussay DP, Nanda GS, Goldfarb PM.
Genetronics, Inc., 11199 Sorrento Valley Road, San Diego CA 92121, USA. dietmarr@genetronics.com
Abstract
Many conventional chemotherapeutic drugs, as well as DNA for cancer
gene therapy, require efficient access to the cell interior to be
effective. The cell membrane is a formidable barrier to many of these
drugs, including therapeutic DNA constructs. Electropermeabilization
(EP, often used synonymously with “electroporation”) has become a useful
method to temporarily increase the permeability of the cell membrane,
allowing a broad variety of molecules efficient access to the cell
interior. EP is achieved by the application of short electrical pulses
of relatively high local field strength to the target tissue of choice.
In cancer therapy, EP can be applied in vivo directly to the tumor to be
treated, in order to enhance intracellular uptake of drugs or DNA.
Alternatively, EP can be used to deliver DNA into cells of healthy
tissue to achieve longer-lasting expression of cancer-suppressing genes.
In addition, EP has been used in ex vivo therapeutic approaches for the
transfection of a variety of cells in suspension. In this paper, we
communicate results related to the development of a treatment for
squamous cell carcinomas of the head and neck, using
electropermeabilization to deliver the drug bleomycin in vivo directly
into the tumor cells. This drug, which is not particularly effective as a
conventional therapeutic, becomes highly potent when the intracellular
concentration is enhanced by EP treatment. In animal model experiments
we found a drug dose of 1 U/cm(3) tumor tissue (delivered in 0.25 mL of
an aqueous solution/cm3 tumor tissue) and an electrical field strength
of 750 V/cm or higher to be optimal for the treatment of human squamous
cell tumors grown subcutaneously in mice. Within 24-48 hours, the
majority of tumor cells are rapidly destroyed by this
bleomycin-electroporation therapy (B-EPT). This raises the concern that
healthy tissue may be similarly affected. In studies with large animals
we showed that normal muscle and skin tissue, normal tissue surrounding
major blood vessels and nerves, as well as healthy blood vessels and
nerves themselves, are much less affected than tumor tissue. Normal
tissues did show acute, focal, and transitory effects after treatment,
but these effects are relatively minor under standard treatment
conditions. The severity of these effects increases with the number of
electric pulse cycles and applied voltage. The observed histological
changes resolved 20 to 40 days after treatment or sooner, even after
excessive EP treatment. Thus, B-EPT is distinct from other ablative
therapies, such as thermal, cryo, or photodynamic ablation, which
equally affect healthy and tumor tissue. In comparison to surgical or
radiation therapy, B-EPT also has potential as a tissue-sparing and
function-preserving therapy. In clinical studies with over 50 late stage
head and neck cancer patients, objective tumor response rates of
55-58%, and complete tumor response rates of 19-30% have been achieved.
Bioelectromagnetics. 2002 Dec;23(8):578-85.
Influence of 1 and 25 Hz, 1.5 mT magnetic fields on antitumor drug potency in a human adenocarcinoma cell line.
Ruiz-Gómez MJ, de la Peña L, Prieto-Barcia MI, Pastor JM, Gil L, Martínez-Morillo M.
Laboratory of Radiobiology, Department of Radiology and Physical
Medicine, Faculty of Medicine, University of Málaga, Teatinos, Málaga,
Spain.
Abstract
The resistance of tumor cells to antineoplastic agents is a major
obstacle during cancer chemotherapy. Many authors have observed that
some exposure protocols to pulsed electromagnetic fields (PEMF) can
alter the efficacy of anticancer drugs; nevertheless, the observations
are not clear. We have evaluated whether a group of PEMF pulses (1.5 mT
peak, repeated at 1 and 25 Hz) produces alterations of drug potency on a
multidrug resistant human colon adenocarcinoma (HCA) cell line,
HCA-2/1(cch). The experiments were performed including (a) exposures to
drug and PEMF exposure for 1 h at the same time, (b) drug exposure for 1
h, and then exposure to PEMF for the next 2 days (2 h/day). Drugs used
were vincristine (VCR), mitomycin C (MMC), and cisplatin. Cell viability
was measured by the neutral red stain cytotoxicity test. The results
obtained were: (a) The 1 Hz PEMF increased VCR cytotoxicity (P <
0.01), exhibiting 6.1% of survival at 47.5 microg/ml, the highest dose
for which sham exposed groups showed a 19.8% of survival. For MMC at
47.5 microg/ml, the % of survival changed significantly from 19.2% in
sham exposed groups to 5.3% using 25 Hz (P < 0.001). Cisplatin showed
a significant reduction in the % of survival (44.2-39.1%, P < 0.05)
at 25 Hz and 47.5 microg/ml, and (b) Minor significant alterations were
observed after nonsimultaneous exposure of cells to PEMF and drug. The
data indicate that PEMF can induce modulation of cytostatic agents in
HCA-2/1(cch), with an increased effect when PEMF was applied at the same
time as the drug. The type of drug, dose, frequency, and duration of
PEMF exposure could influence this modulation.
Biofizika. 2002 Mar-Apr;47(2):376-81.
Immunomodulating effect of electromagnetic waves on production of
tumor necrosis factor in mice with various rates of neoplasm growth.
Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia.
Abstract
The effects of low-density centimeter waves (8.15-18 GHz, 1
microW/cm2, 1 h daily for 14 days; MW) on tumor necrosis factor
production in macrophages of mice with different growth rate of a cancer
solid model produced after hypodermic injection of Ehrlich carcinoma
ascites cells into hind legs were studied. After irradiation, an
increase in the concentration of tumor necrosis factor in
immunocompetent cells of healthy and, specially, of tumor-bearing
animals was observed; and the effect of stimulation was higher upon
exposure of mice carrying rapidly growing tumors. We suggest that the
significant immunomodulating effect of low-density microwaves can be
utilized for tumor growth suppression.
Biofizika. 2001 Jan-Feb;46(1):131-5.
Effect of centimeter m
Cell Biol. Int. 2002;26(7):599-603.
Extremely low frequency (ELF) pulsed-gradient magnetic fields inhibit malignant tumour growth at different biological levels.
Zhang X, Zhang H, Zheng C, Li C, Zhang X, Xiong W.
Source
Biomedical Physics Unit, Department of Physics, Wuhan University, Wuhan, 430072, China.
Abstract
Extremely low frequency (ELF) pulsed-gradient magnetic field (with
the maximum intensity of 0.6-2.0 T, gradient of 10-100 T.M(-1), pulse
width of 20-200 ms and frequency of 0.16-1.34 Hz treatment of mice can
inhibit murine malignant tumour growth, as seen from analyses at
different hierarchical levels, from organism, organ, to tissue, and down
to cell and macromolecules. Such magnetic fields induce apoptosis of
cancer cells, and arrest neoangiogenesis, preventing a supply developing
to the tumour. The growth of sarcomas might be amenable to such new
method of treatment.
icrowaves and the combined magnetic field on the tumor necrosis factor production in cells of mice with experimental tumors.
Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia.
Abstract
The effect of fractionated exposure to low-intensity microwaves
(8.15-18 GHz, 1 microW/cm2, 1.5 h daily for 7 days) and combined weak
magnetic field (constant 65 1 microT; alternating–100 nT, 3-10 Hz) on
the production of tumor necrosis factor in macrophages of mice with
experimental solid tumors produced by transplantation of Ehrlich ascites
carcinoma was studied. It was found that exposure of mice to both
microwaves and magnetic field enhanced the adaptive response of the
organism to the onset of tumor growth: the production of tumor necrosis
factor in peritoneal macrophages of tumor-bearing mice was higher than
in unexposed mice.
J Photochem Photobiol B. 2001 Nov 1;64(1):21-6.
Photodynamic effect on cancer cells influenced by electromagnetic fields.
Pang L, Baciu C, Traitcheva N, Berg H.
Institute of Physics, Nankai University, Nankai, PR China.
The synergism of low-frequency electromagnetic field treatment and
photodynamic effect on killing of human cancer cells is presented. The
weak pulsating electromagnetic field (PEMF) generated by Helmholtz coils
in the mT range influences the permeability of cell membranes for
photosensitizers. Several types of sensitizers were excited by visible
light during incorporation without and with two kinds of PEMF treatment.
In the first part suitable photosensitizers were selected in the
absorption range between 400 and 700 nm against human myeloid leukaemia
K562 and human histiocytic lymphoma U937 cells by treatment of PEMF
consisting of rectangular pulse groups. In the second part amplitude and
frequency dependencies were measured using sinuous PEMF and white light
with the result that after 12 min the PEMF treatment enhanced
photodynamic effectivity by more than 40% over the control value. Taking
into account the influence of many parameters, an additional
optimization will be possible by photodynamic PEMF synergism for an
increased drug delivery in general.
Bioelectromagnetics. 2001 Oct;22(7):503-10.
Pulsed electromagnetic fields affect the intracellular calcium concentrations in human astrocytoma cells.
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