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Nano-Pulse Stimulation Therapy for the Treatment of Skin Lesions

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Nano-Pulse Stimulation (NPS) therapy applies nanosecond pulsed electric fields to cells and tissues. It is a nonthermal modality that uses ultrashort pulses of electrical energy in the nanosecond domain. The cellular response to this therapy can be quite varied depending on the number of pulses applied and the total energy delivered. Reviewed in this study are some clinical trial data describing the effects of NPS therapy on normal skin as well as three different skin lesions as part of the first commercial application of this technology. NPS therapy has been found to clear seborrheic keratosis lesions with an 82% efficacy and sebaceous gland hyperplasia with a 99.5% efficacy. Pilot studies on warts indicated that 60% of the NPS-treated warts were completely cleared within 60 days. NPS therapy can be used to treat cellular lesions in the epidermis and dermis without affecting noncellular components such as collagen and fibrin.
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Nano-Pulse Stimulation Therapy for the Treatment
of Skin Lesions
Richard Nuccitelli, PhD
Abstract
Nano-Pulse Stimulation (NPS) therapy applies nanosecond pulsed electric fields to cells and tissues. It is a
nonthermal modality that uses ultrashort pulses of electrical energy in the nanosecond domain. The cellular
response to this therapy can be quite varied depending on the number of pulses applied and the total energy
delivered. Reviewed in this study are some clinical trial data describing the effects of NPS therapy on normal
skin as well as three different skin lesions as part of the first commercial application of this technology. NPS
therapy has been found to clear seborrheic keratosis lesions with an 82% efficacy and sebaceous gland hy-
perplasia with a 99.5% efficacy. Pilot studies on warts indicated that 60% of the NPS-treated warts were
completely cleared within 60 days. NPS therapy can be used to treat cellular lesions in the epidermis and dermis
without affecting noncellular components such as collagen and fibrin.
Keywords: nanosecond pulsed electric fields, nsPEF, NPS, Nano-Pulse Stimulation, skin, dermatology
Introduction
Nano-Pulse Stimulation (NPS) therapy applies
nanosecond-domain pulses of electrical energy to tis-
sues. These pulses have been shown to specifically target
cellular structures by driving water molecules into lipid bi-
layers of both the plasma membrane and internal organelles to
form nanopores through which small molecules such as Na
+
,
K
+
,orCa
2+
ions can flow. Since Ca
2+
is maintained at very
low levels inside cells compared with the extracellular con-
centration, extracellular Ca
2+
will flow into the cell through
nanopores to generate a transient increase or spike in the in-
tracellular Ca
2+
concentration.
1
Ca
2+
is a very important sig-
naling molecule that is involved in the regulation of many
different cellular functions, so it is not surprising that these
pulses can have a variety of effects on cells from stimulating
secretion in platelets
2
to triggering regulated cell death in skin
lesions and other cells.
3–5
When a sufficient number of pulses
is used, the regulated cell death cascade is triggered leading to
reactive oxygen species generation,
6
DNA fractionation,
7
caspase 3 activation,
8,9
and the translocation of calreticulin
from the ER to the plasma membrane to serve as an ‘‘eat me’
signal for dendritic cells.
9
Many studies have shown that NPS
therapy can trigger regulated cell death in both normal and
malignant cells
10
that can lead to the production of danger-
associated molecular pattern molecules that in turn caninitiate
an immune response.
8,9,11
The first commercial application of
this technology will be for the elimination of unwanted skin
lesions, which will be described in this study.
Results
Characteristics of NPS
The energy delivered by a pulsed electric field is deter-
mined by the product of the applied voltage, current, and pulse
width. Owing to the short pulse width, pulses in the nano-
second domain deliver much less energy than more conven-
tional micro- or millisecond-long pulses. That means that they
are generally nonthermal so that their effect on cells is quite
different from that of the longer conventional pulses. Their
short duration allows them to penetrate into the cell interior
before cellular ions can respond to the imposed field with a
rearrangement that generates an equal and opposite inter-
nal field resulting in zero net electric field within the cell.
Once inside the cell, these pulses can act directly on organ-
elles to generate nanopores in their surrounding membranes
as well. Of course, that will only occur if the field across the
organelles is sufficient to force water defects into those lipid
membranes. That is why NPS technology uses fields on the
order of 30 kV/cm, which can generate the voltage drop of 1 V
required to form nanopores across a submicron diameter
organelle.
Department of Biology, Pulse Biosciences, Hayward, California.
ªRichard Nuccitelli 2019; Published by Mary Ann Liebert, Inc. This Open Access article is distributed under the terms of the Creative
Commons License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any
medium, provided the original work is properly cited.
BIOELECTRICITY
Volume 1, Number 4, 2019
Mary Ann Liebert, Inc.
DOI: 10.1089/bioe.2019.0027
235
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Effects on normal skin
When NPS therapy is applied to normal abdominal and
facial skin that is scheduled for resection, histological anal-
ysis can be performed after resection to determine the effects
of the NPS treatment on skin structures
12
(Fig. 1). Within
1 day, the epidermis exhibits signs of regulated cell death that
include the lack of nuclear staining with standard hematox-
ylin and eosin exposure to thin sections of tissue. One week
later, this dead epidermal layer peels off the skin as a crust or
scab revealing a regenerated epidermis below. By using the
appropriate NPS therapy, the epidermis is regenerated
FIG. 1. H&E-stained sections of abdominal skin fixed at different times. (A) Skin fixed before NPS treatment; (B) 1 day
after treatment; (C) 1 week after treatment. The oval ring marks the healthy epidermis in (A) and (C) as well as the dying
epidermis in (B) with nuclei that do not stain with H&E. This layer in (B) comes off as a necrotic crust one week later in
(C). Reprinted with permission from Kaufman et al.
12
H&E, hematoxylin and eosin; NPS, Nano-Pulse Stimulation.
FIG. 2. Pigmented seborrheic kera-
toses from a single subject shown
before (Pre-NPS) a single NPS treat-
ment of 2.5–10J as well as two time-
points after treatment. Black scale bar
indicates 5 mm. Reprinted with per-
mission from Hruza et al.
13
236 NUCCITELLI
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without scarring and any lesion residing in the epidermis can
be readily removed.
Effects on epidermal lesions
Seborrheic keratosis (SK) is an example of a lesion
residing in the epidermis and the results of a clinical trial
(approved by Biomedical Research Institute of America)
treating SK with NPS therapy have recently been pub-
lished.
13
Using treatment times of less than a minute, a
process of regulated cell death is initiated and the lesion
typically is cleared within a few weeks. One figure from that
publication is included in this study (Fig. 2). Immediately af-
ter NPS treatment, edema and erythema are evident, and a crust
is formed over the following week. The crust usually peels
off within a week taking the lesion with it and hyperpigmen-
tation is often present but fades over the following months.
NPS therapy cleared >82% of the 174 lesions with a single
treatment. These data also showedthatNPStherapyhadno
effect on fibrous components of the skin such as collagen, fibrin,
and elastin.
Effects on dermal lesions
Sebaceous glands reside in the dermis and at times
can proliferate to form a sebaceous gland hyperplasia
(SGH) that appears as a raised papule on the skin, often
with a depression in the center (Fig. 3A). NPS treat-
ment of facial skin has been found to stimulate regulated
FIG. 3. (A) Several SGHs on the forehead; (B) H&E-stained section of SGH taken 30 days post-treatment showing
regulated cell death of the sebaceous glands located in the treatment zone. One sebaceous gland located outside of the
treatment region is unaffected. SGH, sebaceous gland hyperplasia.
FIG. 4. Pairs of images
from four SGHs taken before
(A, C, E, G) and 60 days
after NPS treatment (B, D, F,
H) from four different pa-
tients. Upper photo in each
pair is the reflected light im-
age showing skin surface
and lower photo is the der-
matoscope image of the same
region showing sebaceous
glands. Scale bar in each
image is 2 mm long. Rep-
rinted with permission from
Munavalli et al.
14
NPS THERAPY FOR SKIN LESIONS 237
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cell death in sebaceous glands (Fig. 3B). A nonsignifi-
cant risk clinical trial (approved by Biomedical Research
Institute of America IRB) treating 222 of these lesions
with 0.9–0.5 J resulted in clearance in 99% of the lesions
within 60 days
14
(Fig. 4). Only 18 of these lesions re-
quired a second treatment and that was usually due to
missed targeting on the first treatment. Thirty-two per-
cent of these treated lesions were noted as having a slight
volume loss in this first trial, but ongoing studies show a
reduction in this volume loss when lower NPS energies
are applied.
Warts
One of the most challenging skin lesions to treat is the
common wart due to its high rate of reoccurrence after
treatment. Warts are usually caused by human papilloma
virus 1 or 2 and are commonly treated by freezing with liquid
nitrogen. This treatment usually results in partial shrinkage of
the wart, but it often grows back.
Pilot trials treating warts on the hand and foot using NPS
therapy have been providing promising results (Figs. 5, 6).
Most of the warts treated were recalcitrant and failed to be
cleared after one or more liquid nitrogen treatments. How-
ever, a majority of these recalcitrant 23 warts treated with
NPS therapy were 100% cleared at 60 days post-treatment
(Fig. 6). A pivotal trial with many more subjects is underway.
Discussion
The main advantages of NPS technology is its specificity for
cells and its nonthermal mechanism of action. That enables the
clearance of skin lesions without perturbing the dermal col-
lagen that could lead to scarring. Thus, the cellular epidermis
as well as cellular components of the dermis are specifically
targeted by NPS therapy.The epidermis typicallyforms a crust
that comes off along with any lesions within it, uncovering a
regenerated epidermis. Similarly, cellular structures in the
dermis can be affected by NPS therapy, providing a good
approach to eliminate SGH and possibly acne.
The mechanism used by NPS technology to initiate regu-
lated cell death is unique. By stimulating the pathway of
regulated cell death or apoptosis that is normally used by all
cells at the end of their useful life, NPS technology gives the
instruction to initiate this pathway and the cells do the rest.
That leads to the clean removal of the treated lesions since
they undergo their natural programmed cell death process
with one step in that process being the expression of calre-
ticulin on the cell surface as an ‘‘eat me’’ signal to dendritic
cells. Those cells remove the dying lesion cells cleanly
without scarring.
Conclusion
NPS technology has been shown to be very effective in
the clearance of many types of cellular skin lesions while
sparing the noncellular components of the dermis. The proper
energies can provide scarless lesion elimination with short
treatment times and very high efficacy. This is a physical
modality that will have the same effect of generating nano-
pores in both the organelles and plasma membrane of all cell
types. The cellular response depends on the amount of energy
delivered and can be quite diverse. This first application of
NPS technology to dermatology utilizes its ability to trigger
regulated cell death in cellular targets resulting in the scarless
clearance of unwanted skin lesions in both the dermis and
epidermis.
Disclaimer
This article was written by R.N. and has been submitted
solely to this journal and is not published, in press, or sub-
mitted elsewhere.
Author Disclosure Statement
R.N. is employed by Pulse Biosciences that sponsored the
clinical trials described herein.
Funding Information
Pulse Biosciences funded all of the clinical trials described
in this article.
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FIG. 5. (A) Finger wart
before NPS treatment; (B)
60 days after two treatments
of 7.5 J; (C) Toe wart before
NPS treatment; (D) 120 days
after one NPS treatment of
7.4 J.
FIG. 6. Distribution of the size reduction for 23 warts
measured 60 days after NPS treatment.
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Address correspondence to:
Richard Nuccitelli, PhD
Department of Biology
Pulse Biosciences
3957 Point Eden Way
Hayward, CA 94545
E-mail: rnuccitelli@pulsebiosciences.com
NPS THERAPY FOR SKIN LESIONS 239
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Pulse power technology using nanosecond pulsed electric fields (nsPEFs) offers a new stimulus to modulate cell functions or induce cell death for cancer cell ablation. New data and a literature review demonstrate fundamental and basic cellular mechanisms when nsPEFs interact with cellular targets. NsPEFs supra-electroporate cells creating large numbers of nanopores in all cell membranes. While nsPEFs have multiple cellular targets, these studies show that nsPEF-induced dissipation of ΔΨm closely parallels deterioration in cell viability. Increases in intracellular Ca2+ alone were not sufficient for cell death; however, cell death depended of the presence of Ca2+. When both events occur, cell death ensues. Further, direct evidence supports the hypothesis that pulse rise-fall times or high frequency components of nsPEFs are important for decreasing ΔΨm and cell viability. Evidence indicates in Jurkat cells that cytochrome c release from mitochondria is caspase-independent indicating an absence of extrinsic apoptosis and that cell death can be caspase-dependent and -independent. The Ca2+ dependence of nsPEF-induced dissipation of ΔΨm suggests that nanoporation of inner mitochondria membranes is less likely and effects on a Ca2+-dependent protein(s) or the membrane in which it is embedded are more likely a target for nsPEF-induced cell death. The mitochondria permeability transition pore (mPTP) complex is a likely candidate. Data demonstrate that nsPEFs can bypass cancer mutations that evade apoptosis through mechanisms at either the DISC or the apoptosome.
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Background: Nanosecond pulsed electric field technology (also known as Nano-Pulse Stimulation or NPS) is a nonthermal, drug-free, energy-based technology that has demonstrated effects on cellular structures of the dermis and epidermis in previous clinical studies. Objective: To evaluate the safety and efficacy of a single NPS treatment for clearing seborrheic keratoses (SKs). Materials and methods: This study was a prospective, randomized, open-label, multisite, nonsignificant risk trial in which each subject served as their own control. Fifty-eight subjects had 3 of 4 confirmed SK lesions treated, resulting in 174 total treated lesions. Subjects returned for 5 to 6 follow-up evaluations and photographs. Results: At 106 days after NPS treatment, 82% of treated seborrheic keratoses were rated clear or mostly clear by the assessing physician. Seventy-one percent of lesions were rated clear or mostly clear by the 3 independent reviewers based on the 106-day photographs. All treated subjects returned for all study visits, and 78% of the subjects were satisfied or mostly satisfied with the outcome of the treatment. No adverse events were reported. Conclusion: The NPS procedure was well tolerated and effective in the removal of SKs.
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This nanoelectroablation therapy effectively treats subdermal murine allograft tumors, autochthonous basal cell carcinoma (BCC) tumors in Ptch1+/-K14-Cre-ER p53 fl/fl mice, and UV-induced melanomas in C57/BL6 HGF/SF mice. Here we describe the first human trial of this modality. We treated 10 BCCs on three subjects with 100-1000 electric pulses 100 ns in duration, 30 kV/cm in amplitude, applied at 2 pulses per second. Seven of the 10 treated lesions were completely free of basaloid cells when biopsied and two partially regressed. Two of the 7 exhibited seborrheic keratosis in the absence of basaloid cells. One of the 10 treated lesions recurred by week 10 and histologically had the appearance of a squamous cell carcinoma. No scars were visible at the healed sites of any of the successfully ablated lesions. One hundred pulses were sufficient for complete ablation of BCCs with a single, one minute nanoelectroablation treatment. This article is protected by copyright. All rights reserved.
Article
We have identified a new, nanosecond pulsed electric field (nsPEF) therapy capable of eliminating murine melanomas located in the skin with a single treatment. When these optimized parameters are used, nsPEFs initiate apoptosis without hyperthermia. We have developed new suction electrodes that are compatible with human skin and have applied them to a xenograft nude mouse melanoma model system to identify the optimal field strength, pulse frequency and pulse number for the treatment of murine melanomas. A single treatment using the optimal pulse parameters (2,000 pulses, 100 ns in duration, 30 kV/cm in amplitude at a pulse frequency of 5-7 pulses/sec) eliminated all 17 melanomas treated with those parameters in 4 mice. This was the highest pulse frequency that we could use without raising the treated skin tumor temperature above 40 degrees C. We also demonstrate that the effects of nsPEF therapy are highly localized to only cells located between electrodes and results in very little scarring of the nsPEF-treated skin.