Living the Scientific Life (Scientist, Interrupted)

tags: hair, baldness, hair regeneration, wound healing, Wnt protein

A group of American scientists have discovered how to make the skin of laboratory mice grow new hair follicles, complete with hair, by using a protein that stimulates follicle generating genes in skin cells under wound conditions. They hope this discovery may one day lead to treatments for baldness and abnormal hair growth.

George Cotsarelis and his colleagues from the Department of Dermatology, Kligman Laboratories, University of Pennsylvania School of Medicine, in Philadelphia, found that when skin is wounded, the cells of the epidermis take on the youthful properties of stem cells and generate new hair follicles that are capable of growing new shafts of hair. Positive results have only been achieved in mice so far, but it is likely that human skin will also respond similarly.

In their first experiment described in their Nature paper, Cotsarelis' team surgically removed patches of skin from mice and observed the wounds as they healed over during the following weeks. They noticed that skin cells that had not previously been associated with hair follicles behaved like stem cells and expressed genes that generate hair follicles during skin development. They found that hair growth occurred regardless of the age of the mice, although the new hair was colorless.

In a second experiment, the team looked at genetically engineered mice that express higher levels of a protein called Wnt. These mice produced twice the density of hairs in the normal mice under the same wounding conditions.

"Most people studying skin wounding don't pay a lot of attention to hair follicles. They view wound closure as the end-point," he said.

Cotsarelis helped to found a company called Follica in which he has a stake. This company will develop and market a human follicle regrowth treatment based on a patent currently being filed by the university. The researchers plan to develop a dermabrasion gel that gently damages the skin and initiates the wounding process, together with a topical cream to switch on the follicle generating genes. But it's still early in the development process.

"If it all went perfectly then possibly in two to three years we would have a product, but that's very optimistic," he said.

Sources:

Wnt-dependent de novo hair follicle regeneration in adult mouse skin after wounding by Mayumi Ito, Zaixin Yang, Thomas Andl, Chunhua Cui, Noori Kim, Sarah E. Millar and George Cotsarelis. Nature 447, 316-320 (17 May 2007). doi:10.1038/nature05766 [abstract and PDF]

MedicalNews (quotes)