Research Profile – Promoting Regrowth

Stem cells from hair follicles could improve wound healing in burn victims.

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A type of cell found in hair follicles could be used to help with wound healing and repair skin in patients suffering from severe burns. The cell may also have applications as a treatment to restore hair growth in people who have lost hair as a result of aging or chemotherapy.

"The hair follicle is interesting because, unlike other adult tissues, it repeatedly regenerates itself throughout life without formation of scar tissue," says Dr. Jeff Biernaskie, an assistant professor of comparative biology and experimental medicine at the University of Calgary.

By studying hair follicles more closely, Dr. Biernaskie found that they contain dermal stem cells – relatively unspecialized cells that are perpetually able to divide and turn into various skin cells, hair, fat or even a type of brain cell.

"We showed that these cells lived in hair follicles, that they could induce hair-follicle formation, and that they regulated hair growth. But when we made small wounds [in animal models], we found these cells actually moved out of hair-follicles and to the wound site," he says.

Work now is ongoing to find out just what these cells do at wound sites. "We think they're contributing to the formation of new dermal cells [one type of skin cell] within the wound, but we're trying to confirm this," he says.

Once researchers know exactly what the stem cells do, and more about how they can be turned into specific types of skin cells, they could be harnessed for use in skin grafting procedures that would help burn victims.

With severe burns, the current approach is to transplant skin from a non-burned part of the body and graft it onto the burn site in a procedure called split-thickness skin grafting. Only the top-most layers of skin from the donor site, such as the thigh, are used for this. While this helps replace the skin that was severely damaged in a burn, it's not as good as the original skin that was there.

"The top layers in the graft don't have the supportive dermis underneath which normally supports skin growth in terms of nutrients and blood supply. The dermis also provides structure and support for re-innervation [restoration of nerve function]. So, generally these grafts have abnormal innervation, no hair follicles and no glands. This is an area where something better is needed to help these patients," says Dr. Biernaskie.

Researchers are now focusing on better understanding dermal stem cells – what triggers them into action, how they are directed to form specific types of cells, and which genes regulate their behaviour. The goal is to use the dermal stem cells from hair follicles to form the types of cells that would help regenerate the dermis beneath the skin grafts.

"The idea is that in burn patients, the skin graft would still be done to cover the wound to prevent infection. Then, if you could re-build the dermis underneath with these dermal stem cells you could provide more function to the new skin and hopefully less scarring," he says.

The research, supported in part by the Canadian Institutes of Health Research, could also lead to new treatments for hair loss related to age or from chemotherapy in cancer patients.

"The more we understand how these stem cells are regulated within the skin, the better we can manipulate them outside of the skin for things like wound-healing and improving skin regeneration," Dr. Biernaskie says.

"The hair follicle is interesting because, unlike other adult tissues, it repeatedly regenerates itself throughout life without formation of scar tissue."
– Dr. Jeff Biernaskie, University of Calgary