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Hair Loss News Archives
January 2008
Nerve Regeneration May Be Possible Using Protein In Human Hair
Jan 2008
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.