Navigation
Hair Loss News Archives
December 2005
Hair Follicle Stem Cells Contribute to
Wound Healing, According to New Penn Study
Implications for Skin Problems Related to Diabetes and Other Disorders
(Philadelphia, PA) -
Hair follicle stem cells are important contributors to the wound-healing process, according to new research by investigators at the University of Pennsylvania School of Medicine.
Using an animal model, the
researchers discovered that stem cells in the hair follicle are enlisted to help
heal wounds in the skin. This finding, published online in Nature Medicine last
week, may suggest a therapeutic target for the development of drugs to encourage
and promote wound healing.
Wounds, including skin ulcers and other dermatological problems associated with
diabetes, circulatory problems, and other diseases, are a growing medical
problem in the United States, notes senior author George Cotsarelis, MD,
Associate Professor of Dermatology.
Previous work by the Penn research team had outlined the hair-growth process to show that stem cells in the hair follicle "bulge" area generate new lower hair follicles, which in turn, generate new hair.
Their latest finding-that these same stem cells play a key role in
initiating wound healing-will help lay the foundation for designing more
effective wound-healing strategies.
Even minor wounding resulted in mobilization of follicle stem cells to generate
daughter cells that quickly move into the wound area. “About one-third of the
coverage of the wound came from the stem cells in the hair follicle,” says
Cotsarelis. “
In the future, we think that we will be able to design treatments
that enhance the flow of cells from the hair follicle to the epidermis in the
hope of enhancing wound healing and treating patients with wounds.”
Follow the Blue Light
Clinicians have known for some time that when the skin is abraded new cells come
from the hair follicle.
What remained a mystery was the exact nature of the
origins of the new cells-specifically, what percentage stems from the deep
follicle and what percentage from the epidermis near the wound.
Cotsarelis’ team found that adult stem cells from the lowest portion of the hair
follicle, or “bulge,” quickly ascend the follicle in response to wounding and
ultimately comprise about 30 percent of the new cells in a wound when it first
starts to heal. In addition, the stem cells respond rapidly to surface
wounding-within two days-by generating short-lived “transient-amplifying” cells
that respond to acute wound-healing needs.
Using a genetically engineered mouse designed in their lab, the researchers were
able to visually follow the fate of the stem cells as they migrated from deep
within the skin to the surface wound site. The mouse stem cells express a
reporter gene that encodes an enzyme, which can be detected with a special
blue-color reaction.
“We could see blue lines coming from the follicles going
toward the center of the wound,” says Cotsarelis. “They formed a striking radial
pattern like the spokes of a wheel.”
Hope for Hair Loss?
The research also showed that stem cells might be a therapeutic target in
certain types of hair loss. Using a different engineered mouse also designed in
the Cotsarelis lab, one in which the hair-follicle stem cells could be destroyed
after administration of a drug, the researchers discovered that the animals
permanently lost all of their hair.
This hair loss mimics types of hair loss
seen in humans called scarring alopecias. But, cautions Cotsarelis, more studies
are needed to determine if the loss of hair-follicle stem cells plays a role in
hair loss in humans.
This research was funded in part by the National Institutes of Health.
Other
co-authors in addition to Cotsarelis are Mayumi Ito, Yaping Liu, Zaixin Yang,
Jennifer Nguyen, and Fan Liang, all from Penn, as well as Rebecca J. Morris from
the Columbia University College of Physicians and Surgeons, New York.