There is nothing that strikes fear in a man like the prospect of losing his hair. This sign of age for many men, however, may have finally met its match.

While this is currently no treatment to help men regrow hair — only medications like minoxidil help to stave off any further hair loss — new research out of the Department of Dermatology at the University of Pennsylvania may lead to a drug that can effectively help men to regrow the luscious locks of their youth.

The team of scientists has found a link between the immune system and the ability to regrow hair follicles. They discovered that a type of immune cell called γδ (gamma-delta) T cells produces a protein, fibroblast growth factor 9 (Fgf9), that is key in hair follicle growth during wound healing in mice.

The researchers tested their hypothesis by reducing the expression of Fgf9 and found that the ability of mice to regrow hair was significantly reduced. And performing the opposite experiment, the scientists increased the expression of Fgf9 and found that the mice developed two to three times more hair follicles. They also found that the Fgf9 interacts with wound healing cells called fibroblasts, which then themselves produced more Fgf9 in an amplifying positive feedback loop.

"The findings help explain why humans don't regenerate their hair after wounding," said senior author George Cotsarelis, M.D., professor and chair of Penn's dermatology department, in a press release. "The study also points us to a way to treat wounds and grow hair." Interestingly, humans lack significant numbers of gamma-delta T cells in their skin compared to mice, leading the research team to speculate why humans don't regrow hair after wound healing.

Because Fgf9 is a protein that is excreted outside of cells and travels to other cells and given that it was used on the skin of mice, it is possible that the same treatment could work for people. The researchers suggest that using a chemical that activates Fgf9 production or another pathway called Wnt, which is activated by Fgf9, may also be a course of action in further research.

The University of Pennsylvania has patents on hair-follicle regrowth using Fgf9 and Wnt. Follica, a biotechnology company which has licensed the technology, is in pre-clinical testing to use the technology for hair regrowth. Follica has previously run human Phase IIa clinical trials for hair regrowth using a drug compound. The company was started in 2007 by the lead professor on the current publication, Dr. George Cotsarelis.

"This discovery sheds light on a novel mechanism to regenerate hair follicles and opens an exciting new avenue to develop treatments for hair loss in humans," noted Dr. William Ju of Follica, Inc. in another press release. "Follica has developed a technology platform that is uniquely suited to support clinical translation of these new findings. The Follica platform can be used to induce skin reepithelialization, which creates a "window of opportunity" during which the Fgf9 pathway could be modulated to potentiate hair neogenesis."

Follica has mentioned that combining a medical device, which would disrupt skin, and a chemical to encourage hair regrowth during healing is a viable avenue for pursuing hair regrowth.

 

Source: Gay D, Kwon O, Zhang Z, et al. Fgf9 from dermal γδ T cells induces hair follicle neogenesis after wounding. 2013. Nature Medicine.