From Nature:
Skin may have the capacity to regenerate lost hair follicles from within, according to a new discovery that could yield better treatments for baldness or abnormal hair growth. Researchers in the United States have found that, when skin is wounded, epidermal cells can respond by assuming the properties of stem cells that generate hair follicles and growing new hair. The researchers removed patches of skin from mice and studied the wounds as they healed during the ensuing weeks. Hair growth occurred regardless of the mouse’s age, the researchers report, although the new hairs did not contain pigment.
The process happened naturally after wounding. But the researchers found they could boost the effect by using mice that had been genetically engineered to produce higher levels of proteins that activate the genetic pathway underpinning the transformation to follicle stem cells. These mice responded to wounding by producing twice the density of hairs found in the coats of normal, untreated mice.
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