Study shows hair stem cells might repair nerve damage
US and Japanese scientists reported Monday that tissues differentiated
from human hair follicle stem cells have helped mice with severe
sciatic nerve damage to walk again.
These results suggest that hair follicle stem cells can promote
nervous axon growth and functional recovery after nerve injury,
thus creating a potential opportunity for the clinical treatment
of peripheral nerve diseases.
Embryonic stem cells, which are known to be capable of differentiating
into almost all tissue cells, are at the center of ethical debates
in many countries. Another problem linked to embryonic stem cells
is immunologic incompatibility.
Because of these problems, many recent studies have focused on
using adult stem cells for future clinical applications. Hair
follicles afford a promising source of relatively abundant, accessible,
active, pluripotent adult stem cells.
The research team, made up of researchers from the Massachusetts
Institute of Technology, the Kitasato University of Japan and
the University of California at San Diego, reported these recent
study results in the latest issue of the journal Proceedings of
the National Academy of Sciences.
In earlier studies, the team (led by Robert Hoffman of the University
of California at San Diego) induced hair follicle stem cells to
differentiate into blood vessel cells and neurons. These studies
indicated the potential of hair follicle stem cells to form diverse
Now the team has successfully coaxed the hair follicle stem cells
to evolve into the Schwann cells, a variety of glia cells that
wrap around axons in the peripheral nervous system. When injected
into mice with injured sciatic nerves, the Schwann cells produced
myelin sheaths to surround the nerve axons, after which event
the mice were able to walk normally.
“Therefore, by differentiating into Schwann cells, the
hair follicle stem cells might stimulate the host axons to extend
and, thus, to fill the transection gap,” reported the researchers.
Cell-replacement therapies show lot of promise in the nervous
transplanted embryonic or bone-marrow stem cells have been demonstrated
to promote functional recovery in animal models of
spinal cord of peripheral nerve injury.
The paper does note that though the therapeutic potential of
stem cell transplants is clear, many problems still exist. The
use of fetal tissue raises ethical issues. And “the use
of heterologous human tissue requires immunosuppression, which
is particularly problematic in individuals with long-term, neuron-specific
Because hair follicle stem cells are generated from an autologous
and accessible adult tissue source – namely, the skin – and
because they can readily generate neuron-specific cell types,
they may provide a solution to these problems.
Who knows, in the future, patients with injuries of the nervous
system could be cured with their own hair follicles.
Study shows hair stem cells might repair nerve damage references
- Amoh Y, Li L, Campillo R, Kawahara K, Katsuoka
K, Penman S, Hoffman RM. Implanted hair
follicle stem cells form Schwann cells that support repair of
severed peripheral nerves. Proc Natl Acad Sci U S A. 2005 Dec
6;102(49):17734-8. PMID: 16314569