U.S. patent application number 16/342554 was filed with the patent office on 2020-02-13 for techniques for neuromodulation using electromagnetic energy.
This patent application is currently assigned to THE FEINSTEIN INSTITUTE FOR MEDICAL RESEARCH. The applicant listed for this patent is THE FEINSTEIN INSTITUTE FOR MEDICAL RESEARCH. Invention is credited to Chad E. Bouton, Sangeeta S. Chavan, Kevin J. Tracey.
Application Number | 20200046992 16/342554 |
Document ID | / |
Family ID | 62025502 |
Filed Date | 2020-02-13 |
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United States Patent
Application |
20200046992 |
Kind Code |
A1 |
Tracey; Kevin J. ; et
al. |
February 13, 2020 |
TECHNIQUES FOR NEUROMODULATION USING ELECTROMAGNETIC ENERGY
Abstract
The subject matter of the present disclosure generally relates
to techniques for neuromodulation of tissue that include applying
energy (e.g., electromagnetic energy) into the target tissue to
cause altered activity of a neuron in the tissue. In certain
embodiments, the altered activity causes a change in one or
molecules in the tissue or blood.
Inventors: |
Tracey; Kevin J.; (Old
Greenwich, CT) ; Chavan; Sangeeta S.; (Syosset,
NY) ; Bouton; Chad E.; (Darien, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THE FEINSTEIN INSTITUTE FOR MEDICAL RESEARCH |
Manhasset |
NY |
US |
|
|
Assignee: |
THE FEINSTEIN INSTITUTE FOR MEDICAL
RESEARCH
Manhasset
NY
|
Family ID: |
62025502 |
Appl. No.: |
16/342554 |
Filed: |
October 31, 2017 |
PCT Filed: |
October 31, 2017 |
PCT NO: |
PCT/US2017/059163 |
371 Date: |
April 17, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62415212 |
Oct 31, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61N 1/40 20130101; A61B
5/6825 20130101; A61B 5/418 20130101; A61N 1/36014 20130101; A61B
5/6823 20130101; A61B 5/40 20130101; A61B 5/04001 20130101; A61N
2/02 20130101; A61N 7/00 20130101; A61N 2/006 20130101; A61N
2007/0026 20130101; A61B 2090/378 20160201; A61B 5/407
20130101 |
International
Class: |
A61N 1/40 20060101
A61N001/40 |
Goverment Interests
STATEMENT OF GOVERNMENT SUPPORT
[0002] This invention was made with government support under grant
number W911NF-09-1-0125 awarded by the Defense Advanced Research
Projects Agency (DARPA). The government has certain rights in the
invention.
Claims
1. A method of neuromodulation, comprising: focusing an
electromagnetic energy source on an internal tissue field in a
patient in need of neuromodulation, the internal tissue field
comprising one or more neurons, wherein the electromagnetic energy
source is not in direct contact with the tissue field of focus; and
applying one or more energy pulses to the patient's internal tissue
in the field of focus via the electromagnetic energy source to
cause a change in activity in the patient's internal tissue,
wherein the change is relative to a baseline activity; wherein the
electromagnetic energy source is extracorporeal and the one or more
energy sources are applied transdermally.
2. The method of claim 1, wherein the patient's internal tissue is
a peripheral tissue.
3. The method of claim 1, wherein the patient's internal tissue is
a spleen.
4. The method of claim 1, wherein the patient's internal tissue is
a lymph node.
5. The method of claim 1, wherein the baseline is indicative of the
activity of the internal tissue before applying the one or more
energy pulses.
6. The method of claim 5, wherein a time at which the one or more
energy pulses are applied is designated as time zero, and wherein
the baseline is indicative of the activity at a time immediately
before the energy pulses are applied.
7-9. (canceled)
10. The method of claim 1, wherein the change in activity is a
change in a level of cytokine release in the internal tissue.
11. The method of claim 1, wherein the change in activity is a
change in a level of a cytokine in the patient's blood.
12. The method of claim 1, wherein the change in activity is a
decrease in a level of a cytokine in the patient's blood.
13. The method of claim 10, wherein the cytokine is one or more of
TNF-alpha, IL-1, IL-6 and HMGB1.
14. (canceled)
15. The method of claim 1, wherein the electromagnetic energy
source generates an electromagnetic field.
16. The method of claim 1, wherein the patient has one or more of
endotoxemia, sepsis, septicemia, septic shock, inflammation, and a
pathogenic consequence of an inflammatory condition or an
inflammatory cytokine cascade.
17. The method of claim 1 comprising: controlling an
electromagnetic energy source to apply one or more energy pulses to
a patient's internal immune tissue and according to one or more
parameters of the energy pulses to cause a change in a level of
cytokine release in the internal tissue in direct response to the
one or more energy pulses; receiving information related to the
release of the cytokine relative to a baseline before the one or
more energy pulses are applied; and changing the one or more
parameters based on the information; wherein the electromagnetic
energy source is configured to be positioned on or above a
patient's skin.
18. The method of claim 17, wherein the cytokine is one or more of
TNF-alpha, IL-1, IL-6 and HMGB1.
19. (canceled)
20. The method of claim 17, wherein the patient's internal immune
tissue is a spleen.
21. The method of claim 17, wherein the patient's internal immune
tissue is a lymph node.
22. The method of claim 1, wherein the patient has one or more of
endotoxemia, sepsis, septicemia, septic shock, inflammation, and a
pathogenic consequence of an inflammatory condition or an
inflammatory cytokine cascade.
23. The method of claim 1 comprising: positioning an
electromagnetic field generator at a location at which the
electromagnetic field generator is capable of stimulating one or
more neurons in an internal lymphatic tissue field; and applying
one or more energy pulses to the tissue field via the
electromagnetic field generator to alter activity in the one or
more neurons in response to the one or more energy pulses to
modulate the lymphatic tissue in the field; wherein the energy
pulses are applied non-invasively.
24. The method of claim 23, wherein the lymphatic tissue is a lymph
node and/or spleen.
25. (canceled)
26. The method of claim 24, wherein the number of lymphocytes is
increased in a tissue and/or serum levels of one or more
proinflammatory cytokines is decreased in a subject, thereby
treating an infection and/or an inflammation in the subject.
27-32. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application No. 62/415,212, filed on Oct. 31, 2016, the entirety of
which is incorporated by reference herein for all purposes.
BACKGROUND
[0003] The subject matter disclosed herein relates to
neuromodulation and more specifically, to techniques for modulating
a physiological response using energy applied from an energy
source, in particular an electromagnetic energy source.
[0004] Neuromodulation has been used to treat a variety of clinical
conditions. For example, electrical stimulation at various
locations along the spinal cord has been used to treat chronic back
pain. Such treatment may be performed by an implantable device that
periodically generates electrical energy that is applied to a
tissue to activate certain nerve fibers, which in turn may result
in a decreased sensation of pain. In the case of spinal cord
stimulation, the stimulating electrodes are generally positioned in
the epidural space, although the pulse generator may be positioned
somewhat remotely from the electrodes, e.g., in the abdominal or
gluteal region, but connected to the electrodes via conducting
wires. In other implementations, deep brain stimulation may be used
to stimulate particular areas of the brain to treat movement
disorders, and the stimulation locations may be guided by
neuroimaging.
[0005] Such nervous system stimulation is generally targeted to the
local nerve or brain cell function and is mediated by electrodes
that deliver electrical pulses and that are positioned at or near
the target nervous tissue. However, positioning electrodes at or
near the target is challenging. For example, such techniques may
involve surgical placement of the electrodes that deliver the
energy. In addition, specific tissue targeting via neuromodulation
is challenging. For example, electrodes that are positioned at or
near certain target nerves mediate neuromodulation by triggering
action potentials in nearby nerve fibers, which in turn results in
the propagation of the action potentials through the nerves and
neurotransmitter release at nerve synapses. This may result in a
relatively larger or more diffuse physiological effect than
desired. Because neural pathways are complex and interconnected, a
more targeted modulated effect may be more clinically predictable
and useful.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] These and other features, aspects, and advantages of the
present invention will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings.
[0007] FIG. 1 is a schematic representation of a neuromodulation
system using a pulse generator according to embodiments of the
disclosure.
[0008] FIG. 2 is a block diagram of a neuromodulation system
according to embodiments of the disclosure.
[0009] FIG. 3 is a schematic representation of an ultrasound energy
application device in operation.
[0010] FIG. 4 is a flow diagram of a neuromodulation technique
according to embodiments of the disclosure.
[0011] FIG. 5 shows the results of a standard electrode stimulation
on direct and contralateral popliteal lymph nodes as well as distal
axillary lymph nodes.
[0012] FIG. 6 shows the results of a comparison of lymphocyte
counts in directly stimulated popliteal vs. non-stimulated
popliteal and non-stimulated popliteal lymph nodes after ultrasound
stimulation.
[0013] FIG. 7 shows the concentration of norepinephrine,
epinephrine, and dopamine in lymph node dissociated tissue after
ultrasound stimulation.
[0014] FIG. 8 shows the concentration of norepinephrine,
epinephrine, acetylcholine, and dopamine in the spleen after
ultrasound stimulation.
[0015] FIG. 9A shows the concentration of acetylcholine in the
spleen after ultrasound stimulation for a group antigen-naive
animals relative to a control group of unstimulated antigen-naive
animals.
[0016] FIG. 9B shows the concentration of acetylcholine in the
spleen after ultrasound stimulation for another group of
antigen-naive animals relative to a control group of unstimulated
antigen-naive animals.
[0017] FIG. 9C shows the concentration of acetylcholine in the
spleen after ultrasound stimulation for a group of antigen-treated
animals relative to a control group of unstimulated but
antigen-treated animals.
[0018] FIG. 10A shows the concentration of TNF-alpha in the spleen
for a group of antigen-treated animals relative to a control group
of unstimulated but antigen-treated animals.
[0019] FIG. 10B shows the concentration of TNF-alpha in the serum
for a group of antigen-treated animals relative to a control group
of unstimulated but antigen-treated animals.
[0020] FIG. 10C shows the concentration of TNF-alpha in the liver
for a group of antigen-treated animals relative to a control group
of unstimulated but antigen-treated animals.
[0021] FIG. 11A-11B are examples of a minimally-invasive ultrasound
stimulator (A) and of a minimally-invasive electromagnetic
stimulator (B) that can be inserted through a small incision or
through the vasculature of a subject to be adjacent to a desired
target tissue for localized stimulation of the tissue.
[0022] FIG. 12 shows the serum concentration of TNF after
electromagnetic local tissue stimulation.
[0023] FIG. 13 shows a dose-dependent relationship of the serum
concentration of TNF after electromagnetic local tissue
stimulation.
[0024] FIG. 14 shows a dose-dependent relationship of the serum
concentration of TNF after electromagnetic local tissue
stimulation.
[0025] FIG. 15 shows the serum concentration of TNF after
electromagnetic stimulation in mice after undergoing a
vagotomy.
[0026] FIG. 16 shows the serum concentration of TNF after
electromagnetic local tissue stimulation.
[0027] FIG. 17 shows the spleen concentration of TNF after
electromagnetic local tissue stimulation.
DETAILED DESCRIPTION
[0028] One or more specific embodiments will be described below. In
an effort to provide a concise description of these embodiments,
not all features of an actual implementation are described in the
specification. It should be appreciated that in the development of
any such actual implementation, as in any engineering or design
project, numerous implementation-specific decisions must be made to
achieve the developers' specific goals, such as compliance with
system-related and business-related constraints, which may vary
from one implementation to another. Moreover, it should be
appreciated that such a development effort might be complex and
time consuming, but would nevertheless be a routine undertaking of
design, fabrication, and manufacture for those of ordinary skill
having the benefit of this disclosure.
[0029] Any examples or illustrations given herein are not to be
regarded in any way as restrictions on, limits to, or express
definitions of, any term or terms with which they are utilized.
Instead, these examples or illustrations are to be regarded as
being described with respect to various particular embodiments and
as illustrative only. Those of ordinary skill in the art will
appreciate that any term or terms with which these examples or
illustrations are utilized will encompass other embodiments that
may or may not be given therewith or elsewhere in the specification
and all such embodiments are intended to be included within the
scope of that term or terms. Language designating such non-limiting
examples and illustrations includes, but is not limited to: "for
example", "for instance", "such as", "e.g.", "including" and "in
one (an) embodiment."
[0030] The present techniques relate to local modulation of
axoextracellular or axo somatic or other synapses at axon terminals
in the tissue via the application of energy by an energy source.
Synapses between neurons and nonneuronal cells may be modulated to
alter the activity in the synapse, e.g., the release of
neurotransmitters from the presynaptic neuron. In turn, the altered
activity may lead to local effects. The present techniques permit
energy to be focused in a targeted manner on a volume of tissue
that includes the axon terminals to achieve desired outcomes. In
one example, the axoextracellular synapse is between a neuron and
an immune cell. Accordingly, the application of energy leads to
modulation of immune function in the targeted tissue.
[0031] The human nervous system is a complex network of nerve
cells, or neurons, found centrally in the brain and spinal cord and
peripherally in the various nerves of the body. Neurons have a cell
body, dendrites and an axon. A nerve is a group of neurons that
serve a particular part of the body. Nerves may contain several
hundred neurons to several hundred thousand neurons. Nerves often
contain both afferent and efferent neurons. Afferent neurons carry
signals to the central nervous system and efferent neurons carry
signals to the periphery. A group of neuronal cell bodies in one
location is known as a ganglion. Electrical signals generated in
the nerves (e.g., via upstream stimulation, which may be intrinsic
or externally applied) are conducted via neurons and nerves.
Neurons release neurotransmitters at synapses (connections)
adjacent to a receiving cell to allow continuation and modulation
of the electrical signal. In the periphery, synaptic transmission
often occurs at ganglia.
[0032] The electrical signal of a neuron is known as an action
potential. Action potentials are initiated when a voltage potential
across the cell membrane exceeds a certain threshold. This action
potential is then propagated down the length of the neuron. The
compound action potential of a nerve is complex and represents the
sum of action potentials of the individual neurons in it. The
junction between the axon terminals of a neuron and the receiving
cell is called a synapse. Action potentials travel down the axon of
the neurons to its axon terminal, the distal termination of the
branches of an axon nerve that forms a presynaptic ending or a
synaptic knob of the nerve fiber. The electrical impulse of the
action potential triggers migration of vesicles containing
neurotransmitters to a presynaptic membrane of the presynaptic
ending and ultimately the release of the neurotransmitters into a
synaptic cleft. A synapse that reaches a synaptic knob to convert
the electrical signal of the action potential to a chemical signal
of neurotransmitter release is a chemical synapse. Chemical
synapses may be contrasted with electrical synapses in which the
ionic currents flowing into a presynaptic cell can cross the
barrier of the two cell membranes and enter a postsynaptic
cell.
[0033] The physiological mechanism of the action potential is
mediated by ion movement across the cell membrane. Neurons actively
maintain a resting membrane potential via ion pumps that facilitate
movement of ions such as Na.sup.+, K.sup.+, and Cl.sup.-through the
neuronal membrane. Different types of neurons may maintain
different resting potentials, e.g., -75 mV to -55 mV. An action
potential is generated by an influx of ions, i.e., a movement of
charge to generate a large deviation in the membrane potential that
is associated with a temporary rise in voltage across the membrane,
e.g., a rise to a membrane potential in a range of 30-60 mV. The
action potential in an individual neuron may be initiated in
response to the neurotransmitter release from a presynaptic (e.g.,
upstream) neuron, which in turn results in receptor binding at the
postsynaptic neuron and a cascade of events which leads to the
influx of ions and membrane depolarization that results in an
action potential that is propagated through the nerve.
[0034] Synapses may be located at the junction between two neurons,
which permits an action potential to be propagated from one nerve
cell to another. However, axon terminals may also form synapses at
the junctions between neurons and non-neuronal cells, such as with
immune cells and a neuroimmune junction, muscle cells at a
neuromuscular junction or gland cells. Release of neurotransmitters
into the synaptic cleft and binding to receptors in the
postsynaptic membrane of a postsynaptic cell results in downstream
effects that are dependent on the nature of the presynaptic neuron
and the specific neurotransmitters released as well as the nature
of the postsynaptic cell, e.g., the type of available receptors. In
addition, the post-synaptic effect of an action potential may be
excitatory or inhibitory. An excitatory postsynaptic potential is a
postsynaptic potential that makes the postsynaptic neuron more
likely to fire an action potential while an inhibitory postsynaptic
potential is a postsynaptic potential that makes the postsynaptic
neuron less likely to fire an action potential. Further, several
neurons may work together to release neurotransmitters in concert
that trigger downstream action potentials or inhibit the triggering
of downstream action potentials. Neuromodulation is a technique in
which energy from an external energy source is applied to certain
areas of the nervous system to activate or increase the nerve or
nerve function and/or block or decrease the nerve or nerve
function. In certain neuromodulation techniques, one or more
electrodes are applied at or near target nerves, and the
application of energy is carried through the nerve (e.g., as an
action potential) to cause a physiological response in areas of the
body downstream of the energy application site. However, because
the nervous system is complex, it is difficult to predict the scope
and eventual endpoint of the physiological response for a given
energy application site.
[0035] While strategies for ultrasound modulation of the central
nervous system (i.e. brain tissue) have demonstrated successful
modulation of neural activity, attempts to modulate peripheral
nerves have lagged. For example, ultrasound modulation of the
central nervous system (CNS) involves stimulation of cortical
regions of the brain, which are rich in synaptic structures while
attempts at ultrasound stimulation of peripheral nerves have
targeted nerve trunks that are less rich in/devoid of synaptic
structures. In the present technique, ultrasound stimulation of
peripheral nerves involves targeting one or more axon terminals. In
addition, instead of targeting traditional neuron-neuron synapses
in peripheral tissue, where stimulation results in action potential
propagation, in present techniques, one or more energy pulses are
applied to the patient's internal tissue comprising axon terminals
that include axoextracellular synapses and/or neuronal junctions
with other cell types, e.g., at neuroimmune synapses, where
stimulation of axonal end terminals releases
neurotransmitter/neuropeptide or induces altered neurotransmitter
release in the vicinity of neighboring non-neuronal cells such as
immune or other cells and modulates cell activity.
[0036] Benefits of the present techniques include local modulation
at the target area of the tissue. This local modulation was
demonstrated relative to other modulation techniques, such as
electrical stimulation via electrodes. For example, the present
techniques were examined relative to electrical stimulation, and
changes in contralateral tissue were not observed for the focused
and local energy application.
[0037] Provided herein are techniques for neuromodulation in which
energy from an energy source (e.g., an external or extracorporeal
energy source) is applied to axon terminals in a manner such that
neurotransmitter release at the site of focus of the energy
application, e.g., the axon terminals, is triggered in response to
the energy application and not in response to an action potential.
That is, the application of energy directly to the axon terminals
acts in lieu of an action potential to facilitate neurotransmitter
release into a neuroimmune junction or other neuronal junction with
a non-neuronal cell. The application of energy directly to the axon
terminals further induces an altered neurotransmitter release from
the axon terminal within, e.g., an axoextracellular synapse into
the vicinity of neighboring non-neuronal cells. In one embodiment,
the energy source is an extracorporeal energy source, such as an
ultrasound or electromagnetic energy source. In this manner,
non-invasive and targeted neuromodulation may be achieved directly
at the site of energy focus rather than via modulation at an
upstream site that in turn triggers an action potential to activate
downstream targets. However, it should be understood that
modulation is complex and energy application to organ tissue that
includes target neuronal junctions may also trigger downstream
effects.
[0038] The present techniques may be used in conjunction with lymph
node neuromodulation or modulation of the lymphocyte retention
neuro-immune reflex in addition to modulation of any neuroimmune
interfaces (e.g., the junction or synapse between an axon terminal
and an immune cell). In addition, direct modulation of immune cells
themselves is also contemplated, e.g., immune cells that are not
part of a junction with a neuron. While certain embodiments of the
disclosure are presented in the context of neuroimmune modulation,
it should be understood that the disclosed techniques may be used
in conjunction with other target tissues and with other types of
non-neuronal cells. As provided herein, non-neuronal cells may
include immune cells, muscular cells, secretory cells, etc.
[0039] In certain embodiments, the target tissues are internal
tissues or organs that are difficult to access using electrical
stimulation techniques. Other contemplated tissue targets include
gastrointestinal tissue (stomach, intestines), muscle tissue,
epithelial tissue, connective tissue, cardiac tissue, secretory
tissue, etc. In one example, focused application of energy at a
neuromuscular junction facilitates neurotransmitter release at the
neuromuscular junction without an upstream action potential.
Contemplated modulation targets may include portions of the spleen
responsible for controlling TNF-alpha release from macrophages, a
site in an adrenal gland for controlling dopamine release, or local
sites within a mesenteric plexus controlling inflammation and
macrophage function in gut. In addition, neuroimmune interfaces
that may control antibody production or the functional state of
lymphocytes may be modulated via ultrasound or magnetic energy.
[0040] To that end, the disclosed neuromodulation techniques may be
used in conjunction with a neuromodulation system. FIG. 1 is a
schematic representation of a system 10 for neuromodulation to
achieve neurotransmitter release into a synapse in response to an
application of energy. The depicted system includes a pulse
generator 14 coupled to an energy application device 12 (e.g., an
ultrasound transducer, or a magnetic coil). The energy application
device 12 is configured to receive energy pulses, e.g., via leads,
that in use are directed to a target tissue of the patient, which
in turn results in a clinical effect at the site of energy focus.
In certain embodiments, the pulse generator 14 and/or the energy
application device 12 may be implanted at a biocompatible site
(e.g., the abdomen), and the lead or leads couple the energy
application device 12 and the pulse generator 14 internally. For
example, the energy application device 12 may be a MEMS transducer,
such as a capacitive micromachined ultrasound transducer.
[0041] In certain embodiments, the energy application device 12
and/or the pulse generator 14 may communicate wirelessly, for
example with a controller 16 that may in turn provide instructions
to the pulse generator 14. In other embodiments, the pulse
generator 14 may be an extracorporeal device, e.g., may operate to
apply energy transdermally or in a noninvasive manner from a
position outside of a patient's body, and may, in certain
embodiments, be integrated within the controller 16. In embodiments
in which the pulse generator 14 is extracorporeal, the energy
application device 12 may be operated by a caregiver and positioned
at a spot on or above a patient's skin such that the energy pulses
are delivered transdermally to a desired internal tissue. Once
positioned to apply energy pulses to the desired site, the system
10 may initiate neuromodulation to achieve desired clinical
effects.
[0042] In certain embodiments, the system 10 may include an
assessment device 20 that is coupled to the controller 16 and that
assesses proxy characteristics that are indicative of whether the
modulation goals have been achieved. In one embodiment, the
modulation goal may be local. For example, the modulation may
result in local tissue or function changes, such as tissue
structure changes, increased drainage, etc. In embodiments in which
the energy is applied to a neuroimmune junction, the modulation may
also result in immune function changes, such as a change in a
population of immune cells or a change in a presence or
concentration of chemical compounds by the lymphatic tissue. Based
on the assessment, the modulation parameters of the controller 16
may be altered. For example, if a successful modulation is
associated with a decrease in norepinephrine or tumor necrosis
factor concentration within a defined time window relative to the
start of the procedure (e.g., 5 minutes, 30 minutes), a change may
be desired in the frequency or voltage or other parameters, which
in turn may be provided by an operator to the controller 16 for
defining the energy pulses of the pulse generator 14.
[0043] The system 10 as provided herein may provide energy pulses
according to various modulation parameters. For example, the
modulation parameters may include various stimulation time
patterns, ranging from continuous to intermittent. With
intermittent stimulation, energy or energy pulses delivered for a
period of time at a certain frequency during the signal-on time.
The signal-on time is followed by a period of time with no energy
delivery, referred to as signal-off time. The modulation parameters
may also include stimulation application frequency and duration.
The application frequency may be continuous or delivered at various
time periods within the day or week. The treatment duration may
last for as little as a few minutes to as long as several hours.
Treatment duration with a specified stimulation pattern may last
for one hour, repeated at, e.g., 12 hour intervals. Alternatively,
treatment may be delivered at a higher frequency, say every three
hours, for shorter durations, for example, 30 minutes. The
treatment duration and frequency can be tailored to achieve the
desired result.
[0044] FIG. 2 is a block diagram of certain components of the
system 10. As provided herein, the system 10 for neuromodulation
may include a pulse generator 14 that is adapted to generate a
plurality of energy pulses for application to a tissue of a
patient. The pulse generator 14 may be separate or may be
integrated into an external device, such as a controller 16. The
controller 16 includes a processor 30 for controlling the device.
Software code or instructions are stored in memory 32 of the
controller 16 for execution by the processor 30 to control the
various components of the device. The controller 16 and/or the
pulse generator 14 may be connected to the energy application
device 12 via one or more leads 33.
[0045] The controller 16 also includes a user interface with
input/output circuitry 34 and a display 36 that are adapted to
allow a clinician to provide selection inputs or stimulation
parameters to stimulation programs. Each stimulation program may
include one or more sets of modulation parameters including pulse
amplitude, pulse width, pulse frequency, etc. The pulse generator
14 modifies its internal parameters in response to the control
signals from controller device 16 to vary the stimulation
characteristics of energy pulses transmitted through lead 33 to the
patient. Any suitable type of pulse generating circuitry may be
employed including constant current, constant voltage,
multiple-independent current or voltage sources, etc. The energy
applied is a function of the current amplitude and pulse width
duration.
[0046] In one embodiment, the memory 32 stores different operating
modes that are selectable by the operator. For example, the stored
operating modes may include instructions for executing a set of
modulation parameters associated with a particular treatment site.
Different sites may have different associated modulation
parameters. Rather than having the operator manually input the
modes, the controller 16 may be configured to execute the
appropriate instruction based on the selection. In another
embodiment, the memory 32 stores operating modes for different
types of treatment. For example, activation may be associated with
a different stimulating voltage or frequency range relative to
those associated with depressing or blocking tissue function. In a
specific example, the frequencies are in the range of between 10
mW/cm.sup.2-3 W/cm.sup.2 and Positive Pressure Peak range between
0.5 MPa to 7 MPa. The selected frequencies may depend on the mode
of energy application, e.g., ultrasound or magnetic energy.
[0047] In another embodiment, the memory 32 stores a calibration or
setting mode that permits adjustment or modification of the
modulation parameters to achieve a desired result. In one example,
the stimulation starts at a lower energy parameter and increases
incrementally, either automatically or upon receipt of an operator
input. In this manner, the operator may observe the effects as the
modulation parameters are being changed.
[0048] The controller 16 may also be configured to receive inputs
related to immune and lymphatic function as an input to the
selection of the modulation parameters. For example, when an
imaging modality is used to assess a tissue characteristic, the
controller 16 may be configured to receive a calculated index or
parameter of the characteristic. Based on whether the index or
parameter is above or below a threshold, the modulation parameters
may be modified.
[0049] In another implementation, a successful modulation parameter
set may also be stored by the controller 16. In this manner,
patient-specific parameters may be determined. Further, the
effectiveness of such parameters may be assessed over time. If a
particular set of parameters is less effective over time, the
patient may be developing insensitivity to activated pathways. If
the system 10 includes an assessment device 20, the assessment
device may provide feedback to the controller 16. Based on the
feedback, the processor 16 may automatically alter the modulation
parameters (e.g., step up the frequency or pulse width).
[0050] The system may also include an imaging device 38 that
facilitates focusing the energy application device 12. In one
embodiment, the imaging device 38 may be integrated with the energy
application device 12 such that different ultrasound energies are
applied for targeting and subsequently neuromodulation.
[0051] FIG. 3 is a specific example in which the energy application
device 12 includes an ultrasound transducer 42 that is capable of
applying energy, shown by way of example at a spleen. The energy
application device 12 may include control circuitry for controlling
the ultrasound transducer 42. The ultrasound transducer 42 may also
be configured to acquire image data to assist with focusing the
applied energy on a desired target location.
[0052] The desired target may be an internal tissue or organ that
includes axon end terminals that can be stimulated by direct
application of energy to the axon terminals within a field of focus
of the energy application device 12 to release neurotransmitters.
The energy may be focused on only part of the internal tissue,
e.g., less than 50% of the total volume of the tissue, such that
only axon terminals in the portions of the tissue would directly
receive the energy and release neurotransmitters while the
unstimulated axon terminals outside of the focus area do not. In
some embodiments, axon terminals in the portions of the tissue
directly receiving the energy would induce altered
neurotransmitters release. In this manner, tissue compartments may
be targeted for neuromodulation in a granular manner. In certain
embodiments, the energy may be focused to a volume of less than 25
mm.sup.3. The focal volume and focal depth may be influenced by the
size/configuration of the energy application device 12. The focal
volume of the energy application may be defined by the field of
focus of the energy application device 12.
[0053] The disclosed techniques may be used in assessment of
neuromodulation effects, which in turn may be used as an input to
selecting or modifying neuromodulation parameters. The disclosed
techniques may use direct assessments of tissue condition or
function. The assessment may occur before (i.e., baseline
assessment), during, and/or after the neuromodulation. For example,
for a patient in need of increase lymphatic drainage, such drainage
may be monitored before, during and/or after neuromodulation to
determine if the selected parameters have achieved a sufficient
increase in the drainage. Accordingly, lymphatic drainage may be
assessed by one or more in vivo techniques that determine lymphatic
drainage. In one embodiment, an exogenous contrast agent is
administered either directly into the lymphatic tissue or
indirectly via intradermal injection. For example, a
gadolinium-based contrast media may be used. Either local or
systemic flow may be addressed, depending on the desired clinical
outcome. For example, MR lymphangiography may be used to assess
lymphatic drainage in the limbs. In another embodiment,
fluorescence microlymphangiography (FML) may also be used to assess
lymphatic drainage. FML employs the intradermal administration of a
fluorescent dye, FITC conjugated to dextran (FITC-dextran), and
video fluorescence microscopy techniques to acquire high-resolution
images. In another embodiment, quantum-dot optical lymphatic
imaging may be used for in vivo lymphatic imaging and lymphatic
flow assessment. In yet another embodiment, imaging may include
dyes or indicators that target lymph-specific markers, such as
LYVE-1, Prox-1, podoplanin, and VEGFR3.
[0054] The images from the assessment techniques may be received by
the system for automatic or manual assessment. Based on the image
data, the modulation parameters may also be modified. If the
lymphatic drainage has increased in the presence of stable vital
signs and other health indicators, the stimulation frequency or
voltage may be stepped back to the lowest energy that maintains the
desired elevated lymphatic drainage. In other embodiments, the
change in lymphatic drainage is utilized as a marker of local
neurotransmitter concentration, and used as a surrogate marker for
exposure of local immune (immune interacting) cells to phenotype
modulating neurotransmitters, and effectively a marker of the
predicted effect on immune function. The local concentration may
refer to concentration within a field of focus of the energy
application.
[0055] Additionally or alternatively, the system may assess the
presence or concentration of neurotransmitters or cells in the
lymph tissue or lymphatic fluid. Lymphatic fluid or tissue may be
acquired by a fine needle aspirate, and the assessment of the
presence or levels of neurotransmitters (e.g., peptide
transmitters, catecholamines) may be performed by any suitable
technique.
[0056] In another embodiment, a change in the types and/or numbers
of cells in the lymph node or lymphatic tissue may be an indication
of lymphatic tissue function. The cell population may be assessed
by ex vivo techniques, such as flow cytometry. In another example,
the lymphatic cell population may be assessed by laser-scanning in
vivo confocal microscopy (IVCM) using endogenous contrast.
[0057] FIG. 4 is a flow diagram of a method 50 for stimulating
tissue. In the method, the energy application device is positioned
such that the energy pulses are focused at the desired internal
tissue location at step 52, and the pulse generator applies a
plurality of energy pulses to the internal tissue to stimulate the
target axon terminals to release neurotransmitters and/or induce
altered neurotransmitter release at step 54. Then, the effect of
the stimulation is assessed at step 56. For example, one or more
direct or indirect assessments of a state of tissue function or
condition may be used. Based on the tissue function as assessed,
the modulation parameters of the one or more energy pulses may be
modified at step 58 to achieve the desired clinical result.
[0058] In one embodiment, assessments may be performed before and
after stimulation to assess a change in lymphatic function as a
result of the stimulation. If a desired change in the state of the
assessed characteristic of lymphatic function is above or below a
threshold, appropriate modification in the modulation parameters
may be made. For example, if the change in the characteristic
relative to the threshold is associated with successful activation
of the lymph tissue, the energy applied during neuromodulation may
be stepped back to the minimum level that supports the desired
outcome. If the change in the characteristic relative to the
threshold is associated with insufficient activation of the lymph
tissue, certain modulation parameters, such as the modulation
voltage or frequency, the pulse shape, the stimulation pattern,
and/or the stimulation location may be changed. It should also be
understood that certain desired clinical outcomes may be instead
associated with blocking activation. In such embodiments, an
assessment of decreased neural and/or lymphatic function is
associated with maintaining the modulation parameters, and the
modulation parameters may be modified if an undesired level of
lymphatic activity persists.
[0059] Further, the assessed characteristic or condition may be a
value or index (e.g., a flow rate, a concentration, a cell
population), which in turn may be analyzed by any suitable
technique. For example, a relative change exceeding a threshold may
be used to determine if the modulation parameters are modified. The
successful modulation may be assessed via a measured clinical
outcome, such as a presence or absence of an increase in tissue
structure size (e.g., lymph node size) or a change in concentration
of released molecules e.g., relative to the baseline concentration
before the neuromodulation). In one embodiment, a successful
modulation may involve an increase in concentration above a
threshold, e.g., above a 50%, 100%, 200%, 400%, 1000% increase in
concentration relative to baseline. For blocking treatments, the
assessment may involve tracking a decrease in concentration of a
molecule over time, e.g., at least a 10%, 20%, 30%, 50%, or 75%
decrease in the molecule of interest. Further, for certain
subjects, the successful blocking treatment may involve keeping a
relatively steady concentration of a particular molecule in the
context of other clinical events that may tend to increase the
concentration of the molecule. That is, successful blocking may
block a potential increase. The increase or decrease or other
observable effect may be measured within a certain time window from
the start of treatment, e.g., within 5 minutes, within 30 minutes.
In certain embodiments, if the neuromodulation is determined to be
successful, the change in the neuromodulation is an instruction to
stop applying energy pulses. In another embodiment, one parameter
of the neuromodulation is changed if the neuromodulation is not
successful. For example, the change in modulation parameters may be
an increase in modulation frequency, such as a stepwise increase in
frequency of 10-100 Hz and assessment of the desired characteristic
until successful neuromodulation is achieved. In another
implementation, the pulse width may be changed. In other
embodiments, two or more of the parameters may be changed together.
If the neuromodulation is not successful after multiple parameter
changes, the focus of energy application may be changed.
[0060] Provided herein are techniques for neuromodulation based on
direct and focused stimulation of lymphatic tissue, e.g., lymph
node tissue, spleen tissue, liver tissue, etc. Neuromodulation of
lymph tissue may alter the drainage rate and/or the population of
cells in the drained fluid. Due to co-localization of nerves
innervating the immune cell and lymphatic vessel compartments of
the lymph node, neurotransmitter release may have a simultaneous
effect on both lymphatic and immune function; therefore, the
observable changes in lymphatic function (i.e. easily observable
size and/or flow change in lymphatic tissue using non-invasive
imaging technology) may be used as a surrogate measure of immune
cell neuromodulation (i.e. the simultaneous changes in immune cell
phenotypes due to release of the local neurotransmitters).
[0061] In one embodiment, the invention provides a method of
neuromodulation, comprising:
[0062] focusing an electromagnetic energy source on an internal
tissue field in a patient in need of neuromodulation, the internal
tissue field comprising one or more neurons, wherein the
electromagnetic energy source is not in direct contact with the
tissue field of focus; and
[0063] applying one or more energy pulses to the patient's internal
tissue in the field of focus via the electromagnetic energy source
to cause a change in activity in the patient's internal tissue,
wherein the change is relative to a baseline activity.
[0064] The patient's internal tissue can be, for example, a
peripheral tissue, the spleen, or a lymph node.
[0065] In one embodiment, the baseline is indicative of the
activity of the internal tissue before applying the one or more
energy pulses. In one embodiment, the time at which the one or more
energy pulses are applied is designated as time zero, and the
baseline is indicative of the activity at a time immediately before
the energy pulses are applied.
[0066] The change in activity can comprise, for example, an
alteration in neurotransmitter release in the internal tissue, or a
decrease in a concentration or amount of neurotransmitters released
in the internal tissue, or an increase in a concentration or amount
of neurotransmitters released in the internal tissue.
[0067] The change in activity can comprise, for example, a change
in a level of cytokine release in the internal tissue, a change in
a level of a cytokine in the patient's blood, and/or a decrease or
increase in a level of a cytokine in the patient's blood. The
cytokine can be, for example, one or more of tumor necrosis factor
alpha (TNF-alpha), interleukin-1 (IL-1), IL-6 and high mobility
group box 1 protein (HMGB1).
[0068] The electromagnetic energy source can be extracorporeal and
the one or more energy sources applied transdermally. In a
preferred embodiment, the electromagnetic energy source generates
an electromagnetic field.
[0069] The patient can have, for example, one or more of
endotoxemia, sepsis, septicemia, septic shock, inflammation, and a
pathogenic consequence of an inflammatory condition or an
inflammatory cytokine cascade.
[0070] The invention also provides a method of immunomodulation,
comprising:
[0071] controlling an electromagnetic energy source to apply one or
more energy pulses to a patient's internal immune tissue and
according to one or more parameters of the energy pulses to cause a
change in a level of cytokine release in the internal tissue in
direct response to the one or more energy pulses;
[0072] receiving information related to the release of the cytokine
relative to a baseline before the one or more energy pulses are
applied; and
[0073] changing the one or more parameters based on the
information.
[0074] The cytokine can be, for example, one or more of TNF-alpha,
IL-1, IL-6 and HMGB1.
[0075] The electromagnetic energy source can be configured to be
positioned on or above a patient's skin.
[0076] The patient's internal immune tissue can be, for example the
spleen or a lymph node.
[0077] The patient can have, for example, one or more of
endotoxemia, sepsis, septicemia, septic shock, inflammation, and a
pathogenic consequence of an inflammatory condition or an
inflammatory cytokine cascade.
[0078] The invention further provides a method of neuromodulation,
comprising: positioning an electromagnetic field generator at a
location at which the electromagnetic field generator is capable of
stimulating at least one neuron in a lymphatic tissue; and
[0079] applying one or more energy pulses to the lymphatic tissue
via the electromagnetic field generator to alter activity in the at
least one neuron in response to the one or more energy pulses to
modulate the lymphatic tissue.
[0080] Preferably, the lymphatic tissue is the spleen or a lymph
node.
[0081] Preferably, the energy pulses are applied
non-invasively.
[0082] The invention further provides a method of treating an
infection and/or an inflammation in a subject comprising applying
ultrasound and/or electromagnetic stimulation to one or more of
lymph nodes and/or spleen of the subject in an amount effective to
increase the number of lymphocytes in a tissue and/or decrease
serum levels of one or more proinflammatory cytokines in a subject,
thereby treating an infection and/or an inflammation in the
subject, wherein the ultrasound and/or electromagnetic stimulation
is applied by inserting an ultrasound transducer and/or an
electromagnetic coil through vasculature of the subject or through
a small incision so that the transducer and/or electromagnetic coil
is adjacent to the spleen or lymph nodes.
[0083] The proinflammatory cytokines can comprise, for example, one
or more of tumor necrosis factor alpha and interleukin-1.
[0084] Preferably, the ultrasound and/or electromagnetic
stimulation is effective to modulate neurotransmitter release at
the level of the spleen and/or lymph nodes.
[0085] In regard to electromagnetic stimulation, electric current
flowing through a magnetic coil results in the generation of a
magnetic field. A time varying magnetic field can be used to induce
an electric current in the tissue. By focusing the coil, the
magnetic field can be targeted at a selective site, leading to
stimulation of the neural circuits in the specific target area.
Using magnetic stimulation, it is therefore possible to activate
the neural circuits in vivo in a noninvasive manner. Advantages of
this technique include that it is noninvasive, painless and
independent of clothing and bone/tissue structure. MagPro R30 is an
example of a stimulation and Coil MC-B35 is an example of a coil
that can be used.
EXAMPLES
[0086] Provided herein are techniques that may be applied to
"neuroimmune synapses" or "neuroimmune interfaces." The depicted
examples are directed to application of energy to lymph nodes that
are proximate to the exit lymphatic vessels on lymph nodes. These
nerves may alter the transit of lymphocytes through the lymph node
and when stimulated result in increased lymphocyte retention (i.e.
more lymphocytes in the lymph node). One molecular mechanism for
decreasing lymphocyte egress from the exit lymphatic vessels is
modulation of the ccr7 chemoreceptor activity through coupling and
signaling through a beta-adrenergic receptor.
[0087] Nerves from the sciatic nerve entering the popliteal lymph
node were stimulated in a rat. A bipolar electrode was utilized to
stimulate for 5 minutes at a range of applied current using a 20 Hz
stimulation frequency with 200 microsecond (balanced, biphasic
pulses) After stimulation, the lymph node was excised, dissociated
into a single cells suspension, and then analyzed using a Hemavet
cell counter. The number of lymphocyte cells per cubic mL of
dissociated tissue was plotted for the directly stimulated
popliteal lymph node, the contralateral popliteal lymph node, and
the axillary lymph node. Lymphocyte numbers were statistically
increased only in the stimulated lymph node. Results are shown in
FIG. 5
[0088] In contrast to the electrical stimulation, cells and nerve
terminals within the popliteal lymph node were stimulated by
exposing the lymph node to an ultrasound transducer. Ultrasound
parameters used were as follows: [0089] Frequency: 1.1 MHz [0090]
Burst Cycles: 150 [0091] Burst Period: 500 .mu.s (duty cycle is
close to 30%) [0092] Time of Burst on: 1 min [0093] Estimated
Positive Pressure: 5 MPa [0094] Estimated Negative Pressure: -2 MPa
[0095] Transducer Geometry: Spherically focused with an opening in
the middle [0096] O.D. --70 mm [0097] Hole diameter .about.20 mm
[0098] Focus distance .about.54.8 mm (F number .about.=1) [0099]
Focus diameter 1.8 mm [0100] Focus length 11.7 mm.
[0101] After stimulation the stimulated (and other) lymph nodes
were excised and examined using a cell counter. Only the stimulated
lymph node showed a lymphocyte increase as shown in FIG. 6.
Neurotransmitter levels in the ultrasound stimulated lymph node
differed relative to the electrically stimulated lymph node.
However, the cell count data for lymphocytes was similar in both
the ultrasound and electrically stimulated lymph nodes.
[0102] In addition to local modulation (through efferent nerve
fibers) of lymphocyte egress, electrical stimulation of the nerves
entering the lymph node was found to have distal effects on immune
cell concentrations in the liver and spleen.
[0103] FIG. 7 shows results for neurotransmitter concentration in
ultrasound stimulated lymph nodes. Epinephrine and dopamine went up
in ultrasound stimulated lymph nodes while norepinephrine went down
after ultrasound stimulation. FIG. 8 shows results from ultrasound
stimulation of the spleen. Results were collected 15 minutes after
a 1 minute ultrasound stimulation.
[0104] FIG. 8 shows results for norepinephrine, epinephrine,
dopamine and acetylcholine concentrations in ultrasound stimulated
spleens. FIGS. 9A and 9B show results of acetylcholine
concentration in the spleen for ultrasound-stimulated animals
relative to a control group of unstimulated animals. FIG. 9C shows
acetylcholine concentration in the spleen for a control group of
antigen-treated animals vs. ultrasound-stimulated and
antigen-treated animals. FIGS. 10A-C show TNF-alpha concentrations
for various experimental and control groups. FIG. 10A shows results
from ultrasound stimulation in the spleen, FIG. 10B shows results
from the serum, and FIG. 10C shows results from the liver for a
control group of antigen-treated animals vs. ultrasound-stimulated
and antigen-treated animals. FIGS. 11A-11B show schematic images of
example stimulators.
[0105] In addition to ultrasound energy, the effect of noninvasive
electromagnetic stimulation on local tissue was also examined. In
the technique, a magnetic field was generated via an electric
current applied through a magnetic coil. The magnetic energy
technique may be associated with certain advantages relative to
electrode stimulation. For example, the technique is noninvasive,
painless, and independent of clothing and bone/tissue
structure.
[0106] Mice were anesthetized (ketamine [100 mg/kg, i.m.] and
xylazine [10 mg/kg, i.m.]) and placed in supine position. Mice were
then subjected to transcutaneous electromagnetic stimulation (EMS)
at the cervical region at increasing amplitude (5, 50, 100%) at 2
Hz frequency (total 120 cycles). Change in amplitude is
proportional to the amount of current delivered. One group of mice
did not receive stimulation (0% amplitude) and served as the sham
control. Two hours after stimulation, animals were challenged with
endotoxin to induce endotoxemia (where endotoxemia is a model of
biological threat attack or of hemorrhagic shock or of a condition
is which the inflammatory cytokine cascade is active). Serum
samples were collected after 90 min and levels of TNF were assessed
by ELISA.
[0107] FIG. 12 shows the results of electromagnetic stimulation on
serum TNF levels. The results show that transcutaneous
electromagnetic stimulation attenuates serum TNF levels in
endotoxemia-challenged mice. Mice were subjected to electromagnetic
stimulation at the cervical region for 1 min (50% amplitude, 2 Hz
frequency, total 120 cycles). The control group did not receive any
stimulation. After 2 hrs, mice were subjected to endotoxemia (10
mg/kg endotoxin, i.p.), and blood was collected after 90 min. Serum
TNF levels were determined by ELISA.
[0108] FIG. 13 shows the results of electromagnetic stimulation on
serum TNF levels in response to endotoxin challenge. The results
show that transcutaneous electromagnetic stimulation attenuates
serum TNF levels in a dose-dependent manner in endotoxemic mice.
Mice were subjected to electromagnetic stimulation at the cervical
region (1 min--0, 5, 50% amplitude and 6 sec--100% amplitude, 2 Hz
frequency, total 120 cycles). After 2 hrs, mice were subjected to
endotoxemia (10 mg/kg endotoxin, i.p.), and blood was collected
after 90 min. Serum TNF levels were determined by ELISA.
[0109] FIG. 14 shows the results of electromagnetic stimulation on
serum TNF levels. The results show that transcutaneous
electromagnetic stimulation attenuates serum TNF levels in dose
dependent manner in endotoxemic mice. Mice were subjected to
electromagnetic stimulation at the cervical region (1 min--0, 12,
25, 50% amplitude, 2 Hz frequency, total 120 cycles). After 2 hrs,
mice were subjected to endotoxemia (10 mg/kg endotoxin, i.p.), and
blood was collected after 90 min. Serum TNF levels were determined
by ELISA.
[0110] Another set of experiments examined the effect of
noninvasive electromagnetic energy on mice that had previously been
subjected to left vagotomy or sham surgery. After 7 days of
recovery, mice were subjected to transcutaneous electromagnetic
stimulation or sham stimulation at the cervical region (50%
amplitude, 2 Hz frequency, total 120 cycles). Two hours after
stimulation, animals were challenged with endotoxin to induce
endotoxemia. Serum samples were collected after 90 min and levels
of TNF were assessed by ELISA.
[0111] FIG. 15 shows the results of electromagnetic stimulation on
serum TNF levels. The results show that vagotomy attenuates the
effect of subsequent transcutaneous electromagnetic stimulation.
Mice were subjected to left cervical vagotomy or sham vagotomy.
After 7 days, EMS was carried out at the cervical region (1 min--0,
50% amplitude, 2 Hz frequency, total 120 cycles). After 2 hrs, mice
were subjected to endotoxemia (10 mg/kg endotoxin, i.p.), and blood
was collected after 90 min. Serum TNF levels were determined by
ELISA.
[0112] In an additional study to analyze whether localized
transcutaneous electromagnetic stimulation attenuates systemic
and/or local immune responses, mice were anesthetized (ketamine
[100 mg/kg, i.m.] and xylazine [10 mg/kg, i.m.]). Anesthetized mice
were placed in supine position. Mice were subjected to
transcutaneous electromagnetic stimulation (EMS) targeted at the
spleen tissue field at 50% amplitude at 2 Hz frequency (total 120
cycles). One group of mice did not receive stimulation (0%
amplitude) and served as the sham control. Two hours after
stimulation, animals were challenged with endotoxin to induce
endotoxemia (where endotoxemia is a model of biological threat
attack and/or hemorrhagic shock and/or a condition in which the
inflammatory cytokine cascade is active). Serum and spleen samples
were collected after 90 min and levels of TNF were assessed by
ELISA.
[0113] FIG. 16 shows the results of electromagnetic stimulation on
serum TNF levels. The results show that local transcutaneous
electromagnetic stimulation attenuates serum TNF levels in
endotoxemic mice. Mice were subjected to electromagnetic
stimulation at the spleen region (1 min--0, 50% amplitude, 2 Hz
frequency, total 120 cycles). After 2 hrs, mice were subjected to
endotoxemia (10 mg/kg endotoxin, i.p.), and blood was collected
after 90 min. Serum TNF levels were determined by ELISA.
[0114] FIG. 17 shows the results of electromagnetic stimulation on
serum TNF levels. The results show that local transcutaneous
electromagnetic stimulation attenuates local TNF levels in
endotoxemic mice. Mice were subjected to electromagnetic
stimulation at the spleen region (1 min--0, 50% amplitude, 2 Hz
frequency, total 120 cycles). After 2 hrs, mice were subjected to
endotoxemia (10 mg/kg endotoxin, i.p.), and spleen was collected
after 90 min. Serum TNF levels were determined by ELISA.
[0115] This written description uses examples to disclose the
invention and also to enable any person skilled in the art to
practice the invention, including making and using any devices or
systems and performing any incorporated methods. The patentable
scope of the invention is defined by the claims, and may include
other examples that occur to those skilled in the art. Such other
examples are intended to be within the scope of the claims if they
have structural elements that do not differ from the literal
language of the claims, or if they include equivalent structural
elements with insubstantial differences from the literal languages
of the claims.
* * * * *