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The NASA Light-Emitting Diode Medical Program
- Progress in Space Flight and Terrestrial Applications
Harry T. Whelan, M.D.1a,2,3, John
M Houle, B.S.1a,
Noel T. Whelan1a,3, Deborah L. Donohoe,
A.S., L.A.T.G.1a,
Joan Cwiklinski, M.S.N., C.P.N.P.1a,
Meic H. Schmidt, M.D.1c,
Lisa Gould, M.D., PhD.1b, David Larson,
M.D.1b,
Glenn A. Meyer, M.D.1a, Vita Cevenini3,
Helen Stinson, B.S.3
1a Departments
of Neurology, 1bPlastic Surgery and
1cNeurosurgery,
Medical College of Wisconsin, Milwaukee, WI 53226,
(414) 456-4090
2Naval Special Warfare Group
TWO, Norfolk, VA 23521, (757) 462-7759
3NASA-Marshall Space Flight
Center, AL 35812, (256) 544-2121
Abstract. This work is
supported and managed through the NASA Marshall Space Flight Center
- SBIR Program. Studies on cells exposed to microgravity and hypergravity
indicate that human cells need gravity to stimulate cell growth.
As the gravitational force increases or decreases, the cell function
responds in a linear fashion. This poses significant health risks
for astronauts in long term space flight. LED-technology developed
for NASA plant grown experiments in space shows promise for delivering
light deep into tissues of the body to promote wound healing and
human tissue growth. This LED-technology is also biologically optimal
for photodynamic therapy of cancer.
LED-ENHANCEMENT OF CELL GROWTH
The application of light therapy with the use of NASA LED's will
significantly improve the medical care that is available to astronauts
on long-term space missions. NASA LED's stimulate the basic energy
processes in the mitochondria (energy compartments) of each cell,
particularly when near-infrared light is used to activate the color
sensitive chemicals (chromophores, cytochrome systems) inside. Optimal
LED wavelengths include 680, 730 and 880 nm. The depth of near-infrared
light penetration into human tissue has been measured spectroscopically
(Chance, et al 1988). Spectra taken from the wrist flexor muscles
in the forearm and muscles in the calf of the leg demonstrate that
most of the light photons at wavelengths between 630-800 nm travel
23 cm through the surface tissue and muscle between input and exit
at the photon detector. Our laboratory has improved the healing
of wounds in laboratory animals by using NASA LED light and hyperbaric
oxygen. Furthermore, DNA synthesis in fibroblasts and muscle cells
has been quintupled using NASA LED light alone, in a single application
combining 680, 730, and 880 nm each at 4 Joules per centimeter squared.
Muscle and bone atrophy are well documented in astronauts, and
various minor injuries occurring in space have been reported not
to heal until landing on Earth. Long term space flight, with its
many inherent risks, also raises the possibility of astronauts being
injured performing their required tasks. The fact that the normal
healing process is negatively affected by microgravity requires
novel approaches to improve wound healing and tissue growth in space.
NASA LED arrays have already flown on Space Shuttle missions for
studies of plant growth. The U.S. Food and Drug Administration (FDA)
has approved human trials. The use of light therapy with LED's is
an approach to help increase the rate of wound healing in the microgravity
environment, reducing the risk of treatable injuries becoming mission
catastrophes.
Wounds heal less effectively in space than here on Earth. Improved
wound healing may have multiple applications which benefit civilian
medical care, military situations and long-term space flight. Laser
light and hyperbaric oxygen have been widely acclaimed to speed
wound healing in ischemic, hypoxic wounds. An excellent review of
recent human experience with near-infrared light therapy for wound
healing was published by Conlan, et al in 1996. Lasers provide low
energy stimulation of tissues which results in increased cellular
activity during wound healing (Beauvoit, 1989, 1995; Eggert, 1993;
Karu, 1989; Lubart, 1992, 1997; Salansky, 1998; Whelan, 1999; Yu,
1997). Some of these activities include increased fibroblast proliferation,
growth factor syntheses, collagen production and angiogenesis. Lasers,
however, have some inherent characteristics, which make their use
in a clinical setting problematic, including limitations in wavelengths
and beam width. The combined wavelengths of light optimal for wound
healing cannot be efficiently produced, and the size of wounds which
may be treated by lasers is limited. Light-emitting diodes (LED's)
offer an effective alternative to lasers. These diodes can be made
to produce multiple wavelengths, and can be arranged in large, flat
arrays allowing treatment of large wounds. Our experiments suggest
potential for using LED light therapy at 680, 730 and 880 nm simultaneously,
alone and in combination with hyperbaric oxygen therapy, both alone
and in combination, to accelerate the healing process in Space Station
Missions, where prolonged exposure to microgravity may otherwise
retard healing. NASA LED's have proven to stimulate wound healing
at near-infrared wavelengths of 680, 730 and 880 nm in laboratory
animals, and have been approved by the U.S. Food and Drug Administration
(FDA) for human trials. Furthermore, near-infrared LED light has
quintupled the growth of fibroblasts and muscle cells in tissue
culture. The NASA LED arrays are light enough and mobile enough
to have already flown on the Space Shuttle numerous times. LED arrays
may prove to be useful for improving wound healing and treating
problem wounds, as well as speeding the return of deconditioned
personnel to full duty performance. Potential benefits to NASA,
military, and civilian populations include treatment of serious
burns, crush injuries, non-healing fractures, muscle and bone atrophy,
traumatic ischemic wounds, radiation tissue damage, compromised
skin grafts, and tissue regeneration.
LED-PHOTODYNAMIC THERAPY FOR CANCER
Photodynamic therapy (PDT) is a cancer treatment modality that
recently has been applied as adjuvant therapy for brain tumors.
PDT consists of intravenously injecting a photosensitizer, which
preferentially accumulates in tumor cells, into a patient and then
activating the photosensitizer with a light source. This results
in free radical generation followed by cell death. The development
of more effective light sources for PDT for brain tumors has been
facilitated by applications of space light-emitting diode array
technology; thus permitting deeper tumor penetration of light and
use of better photosensitizers. Lutetium Texaphyrin (Lutex) and
Benzoporphyrin Derivative (BPD) are new, second generation photosensitizers
that can potentially improve PDT for brain tumors. Lutex and BPD
have major absorption peaks at 730 nm and 680 nm respectively, which
gives them two distinct advantages. First, longer wavelengths of
light penetrate brain tissue easily so that larger tumors could
be treated; and second, the major absorption peaks mean that more
of the drug is activated upon exposure to light. Tumorcidal effects
of Lutex and BPD have been studied in vitro using canine
glioma and human glioblastoma cell cultures. Using light-emitting
diedes (LED) with peak emissions of 728 nm and 680 nm as a light
source, a greater than 50 percent cell kill was measured in both
cell lines by tumor DNA synthesis reduction. The effectiveness of
Lutex and BPD against tumor cells in vitro thus established, we
have taken the first step toward determining their in vivo efficacy
by performing experiments to determine the largest doses of both
Lutex, or BPD, and light that can be administered to dogs before
toxicity is seen, i.e. the maximum tolerated dose (MTD). Using this
dose allows us to effect maximum tumor cell destruction during in
vivo studies.
For longer wavelengths of light, the improved NASA LED-technology
is required. LED's are an effective alternative to lasers for PDT.
Laser conversion to near-infrared wavelengths is inherently costly
and inefficient, using an argon ion or KTP/YAG laser beam that is
converted by a dye module, usually to 630 nm. LED's have been frequently
used to emit longer wavelength broad spectrum near-infrared light
of 25-30 nm bandwidths. LED lamps traditionally consist of an array
of semiconducting LED chips. In recent years, improvements in semiconductor
technology have substantially increased the light output of LED
chips. A novel type of LED chip is based on the semiconductor Aluminum
Gallium Arsenide (AlGaAs). These LED chips have been manufactured
to emit light with peak wavelengths of 680 and 730 nm, which are
optimal wavelengths for the absorption spectrum of the new photosensitizers
used for cancer PDT.
Human trials have begun at the Medical College of Wisconsin, Naval
Special Warfare Command and NASA-Marshall Space Flight Center.
Photodynamic Therapy with NASA LED Human Subjects
Preclinical studies of LED-photodynamic therapy were reported previously
(Whelan, 1993, 1999; Schmidt, 1996, 1999)
The first patient treated with the NASA LED probe in our Photodynamic
Therapy Phase II study, is a 20 year old female who underwent
PDT on May 4, 1999 for a brain tumor (anaplastic ependynoma). She
had had two previous PDT treatments with laser light in another
area of the brain. The most recent tumor recurrence formed in a
different location of the brain than the previous two sites and
is thought to be the result of the laser light not being able to
penetrate the tissue deep enough to prevent recurrence. LED and
photofrin together allow for deeper penetration of tissue, thereby
exposing surrounding tissue which may contain stray cancer cells
to the LED light.
Post surgically, she experienced some edema as is expected from
brain surgery, and was treated successfully, and discharged on May
14, 1999. Follow-up MRI scans do not demonstrate tumor growth. A
subsequent 21 year-old male with brain tumor (glioblastoma) was
treated August 25, 1999, with LED-photodynamic therapy, he tolerated
the procedure well and shows no evidence residual tumor on subsequent
neuro imaging.
WOUND HEALING WITH NASA LED
Preclinical LED-Wound Healing studies were reported previously
(Whelan, 1999)
LED-Diabetic Mice
Type II, Diabetic Mice with excisional skin wounds were treated
with LED's at 680, 730, and 880 nm, 4J/cm2 of energy.
A repeated measures analysis was conducted using a General Linear
Model with SqrtArea as the dependent variable and Treat
as the independent variable. The interaction effect Day*Treat is
significant (p-value=.0095), indicating there there is a significant
difference between treatments on some days. This test is of primary
interest in this situation, because it shows that the treatments
are effective for some part of the treatment period. This analysis
was carried out using the SAS statistical software package, published
by the SAS Institute, Inc.
LED-Human Subjects
Pt #1 is a 31 year-old white female insulin dependent diabetic
(type 1) with end-stage renal disease status post renal transplant
failure and bilateral below knee amputations. Her left amputation
site has poor healing compared to the right. She was receiving Hyperbaric
Oxygen therapy because of bilateral arterial insufficiency ulcers
on her hands. In January of 1999 she had a hangnail on her right
third finger and sores developed at the tip. Multiple fissures and
sores on both hands further occurred. Sores covered with black eschar
developed and her hands are dry with very limited range of motion.
She has similar processes on both hands and had similar processes
developing on her feet prior to undergoing bilateral below the knee
amputations. At that time she complained of cold-induced cyanosis
of the fingers and has been developing fissuring of the skin on
her hands and some small spots on her fingers. She is a nonsmoker
and has been on dialysis for her renal failure. The renal failure
and the arterial insufficiency ulcers of her extremities have been
felt to be due to vasculitis She does not use alcohol and has no
drug allergies. She had renal transplant for renal failure in 1996
with removal of the transplanted kidney in 1998. She has received
Prednisone and Cytoxan for her vasculitis and she also takes Synthroid
for hypothyroidism. She has had problems in the past with gastroparesis
and had a temporary percutaneous endoscopic gastrostomy tube in
place, but has never had a diagnosis of gastroesophageal dysmotility.
She has no history of calcinosis and she is anuric because of renal
failure. A renal biopsy performed December 5, 1997 of her transplanted
kidney showed "focal necrotizing glomerular nephritis, no evidence
of acute rejection, no evidence of recurrent diabetic nephopathy".
She received 20 treatments of 8 J/cm2 NASA LED light
therapy to all surfaces of both hands. Prior to starting treatment
her hands were cold and dusky, lacking sensation. They had many
eschar ulcerations. After light treatment we noted an improvement
in color and hands were warm to the touch. Her complaints of pain
and itching indicated a return of sensation.
PT #2 is a 76 year-old white mail, borderline diabetic with two
open sores on his right medial malleolus. These wounds were traumatic,
caused when he was wounded by mortar fire during World War II in
the Battle of the Bulge. He has had open sores in that area since
that time. These wounds have required two split thickness grafts.
One was performed in 1945 and another in 1965. Both grafts have
been of questionable success. Mr. Marek has been treated with 52
Hyperbaric Oxygen Treatments to date and has received 19 treatments
of 8 J/cm2 of NASA LED therapy to his ankle wound. At
the start of NASA LED treatment the area had opened into one large
2cm X 3cm wound draining sanguinous fluid. Since treatment we have
seen an increase in tissue granulation from the inside towards the
outer edges of the wound. Area has decreased to 1.5cm X 2.8cm and
there is a significant decrease in drainage. Transcutaneous Oxygen
Measurement (T.C.pO2) readings have shown an improvement
in vasculature to the area.
Further In Vitro LED Cell Growth Studies
In-vitro studies continue with the 3T3 Fibroblasts, and L6 Rat
Skeletal Muscle cell line. Stimulation with LED's clearly shows
proliferation of both cell lines with the DNA synthesis assay. The
studies indicate the 3T3 Fibroblasts with stimulation of 4 J/cm2,
8 J/cm2 and 12 J/cm2 of energy show proliferation
of cells within 3 hours after exposure to LED. Studies on the L6
Skeletal Muscle depict growth over a period of 48 hours after exposure
to 4 J/cm2 of energy. This data demonstrates immediate
benefit of LED exposure in-vitro, as in the 3T3 Fibroblasts, but
also over a period of time, over 48 hours with the L6 Muscle
Cells.
ACKNOWLEDGEMENTS
We wish to thank Karen Zeqiri for assistance in manuscript preparation.
The LED arrays were provided by Quantum Devices, Inc., Barneveld,
WI. We also gratefully acknowledge the Department of Defense, Air
Force Material Command, Armstrong Laboratories, Davis Hyperbaric
Laboratory, Brooks Air Force Base, TX for providing the hyperbaric
chamber used in this research. The hyperbaric oxygen treatments
of our human subjects were performed by Estelle Woodard, C.R.T.,
C.H.T. This work was supported by the National Aeronautics and Space
Administration, Marshall Space Flight Center SBIR grants: NAS8-99015
and NAS8-97277, Children's Hospital Foundation, the MACC Fund and
Quantum Devices, Inc.
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