Protein in Human Hair Shows Promise for Regenerating Nerves
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WINSTON-SALEM, N.C. – A protein found in human hair shows
promise for promoting the regeneration of nerve tissue and could lead
to a new treatment option when nerves are cut or crushed from trauma.
In the current issue of Biomaterials, scientists from Wake
Forest University School of Medicine reported that in animal studies
the protein keratin was able to speed up nerve regeneration and
improve nerve function compared to current treatment options.
"We found that the nerve repair happened more quickly and
consistently, and that functional recovery was higher," said Mark Van
Dyke, Ph.D., senior author and an assistant professor of regenerative
medicine. "The fact that we were able to accomplish this with gels
made from keratin is pretty remarkable."
Current treatments for repairing damaged nerves include
microsurgery to sew two ends of the nerve together, using a nerve
from another part of the body to replace a damaged section, or
placing an empty tube between the cut ends so that nerve fibers can
grow through it and back into the muscle.
Grafting a nerve from another part of the body is usually the
most effective option, but it creates another injury site and isn't
possible in all patients. The tubes, known as nerve guidance
conduits, cannot be used in gaps longer than three or four
centimeters. In addition, nerve regeneration with this method is not
always successful. For example, after about age 17, nerves don't
regenerate as well.
Laboratory scientists have tried placing natural materials, such
as collagen, into the conduits to promote nerve regeneration. Van
Dyke's team was the first to use keratin, which is believed to
contain molecules that regulate cell behavior.
The scientists collected human hair from a local barber shop and
chemically processed it to remove the keratin. They purified the
keratin protein and used it to form gels that were then used to fill
the nerve guidance conduits. They studied how keratin affects the
activity of Schwann cells, which play a vital role in nerve
regeneration. These cells produce signals that tell nerve cells to
begin regenerating and "remodel" the blood clot that has formed so
that nerve cells can grow across it.
"By using keratin to activate these cells, we're trying to tap
into the natural healing cascade," said Van Dyke. "We believe that
keratin helps amp up Schwann cell activity and give the nerve
regeneration process a head start."
The laboratory studies showed that keratin activated Schwann
cells and increased their proliferation and migration. Next, the
scientists used a keratin-filled tube to attempt to repair a 4
millimeter nerve gap in mice -- a fairly significant gap considering
the size of the animal.
The results from these animals were compared with animals
treated with an empty nerve guidance conduit and with animals treated
with a nerve graft.
After six weeks, 100 percent of the animals in the keratin and
nerve graft groups showed visible nerve regeneration across the gap,
compared to only 50 percent who got the empty conduit. The speed of
repair was best in the keratin group.
The scientists then tested the function of the regenerated
nerve. The speed of nerve impulses was best in the keratin group. The
amount of signal that got through the nerve was better in the keratin
group than in the empty tube group. The study was recently
highlighted in the journal Science.
"The results suggest that a conduit filler derived from hair
keratins can promote an outcome comparable to a grafted nerve," said
Van Dyke.
In the study, the nerve function did not translate into recovery
of muscle function, but the scientists suspect they may have tested
too early, before the nerve had time to regenerate to the muscle. It
is known that muscle function recovery lags behind nerve recovery.
Future studies will focus on regeneration across larger gaps and will
test whether nerve regeneration results in a return of muscle
function.
The research was conducted by the Wake Forest Institute for
Regenerative Medicine (WFIRM) and the Department of Orthopaedic
Surgery and was funded internally. Additional studies will be funded
by the Errett Fisher Foundation.
In addition to Van Dyke, members of the research team and co-
authors on the paper include graduate student Paulina Sierpinski,
B.S., and orthopaedic resident Jeffrey Garrett, M.D., (co-first
authors), orthopaedic resident Jianjun Ma, M.D., graduate student and
orthopaedic resident Peter Apel, M.D., graduate student David Klorig,
B.S., orthopaedic surgery professor Thomas Smith, Ph.D., orthopaedic
surgery chair L. Andew Koman, M.D., and WFIRM director Anthony Atala,
M.D.
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Media Contacts: Karen Richardson, krchrdsn@wfubmc.
Koontz, shkoontz@wfubmc.
336-716-4587
Wake Forest University Baptist Medical Center is an academic health
system comprised of North Carolina Baptist Hospital and Wake Forest
University Health Sciences, which operates the university's School of
Medicine. U.S. News & World Report ranks Wake Forest University
School of Medicine 18th in primary care and 44th in research among
the nation's medical schools. It ranks 35th in research funding by
the National Institutes of Health. Almost 150 members of the medical
school faculty are listed in Best Doctors in America.
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Children's Neurobiological Solutions
http://www.CNSfoundation.org/
Cord Blood Registry
http://www.CordBlood.com/at.cgi?a=150123
The CNS Healing Group
http://groups.yahoo.com/group/CNS_Healing
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