Hair Follicles May Regrow After Head Wounds

Mar. 23 -- WEDNESDAY, May 16 (HealthDay News) -- A chance finding in wounded lab mice could point the way to reversing hair loss, scientists say.

While studying the healing of wounds in mice, a team at the University of Pennsylvania noticed that the animals developed new hair follicles after their skin was scraped.

This is very unusual, because "the dogma was that when you're born, you're stuck with the number of hair follicles that you have," said study co-author Dr. George Cotsarelis, director of the university's Hair and Scalp Clinic. And, if the follicles die -- as occurs during aging -- they can't be revived.

No one knows if new follicle growth occurs in wounded humans or if researchers can find a way to harness the hair-growing effect without having to actually hurt people.

But scientists are hopeful, especially considering that current treatments for baldness do not create new follicles to replace ones that have died.

"We're amazed that we're getting follicles to form," Cotsarelis said. He believes the findings could even "lead to a better understanding of regeneration that might be important for treating wounds and larger sorts of injuries down the road."

Apparently, something in the mice's healing process reprograms stem cells in the skin to start making new follicles, Cotsarelis said. Essentially, he said, the process is like rebooting a computer and sending out a new command through a gene. "You're getting the clock to go back to where it was at birth," he explained.

The result is new follicles that seem to act just like follicles should -- they sprout hair.

The study is published in the May 17 issue of the journal Nature.

The wounds that appear to cause the hair regrowth in the mice are similar to a common dermatological treatment known as dermabrasion, Cotsarelis said. In dermabrasion, layers of skin are scraped off and healing begins.

So, why not start treating balding people with dermabrasion on their heads? Cotsarelis -- who is forming a company to explore ways to develop the treatment for human use -- cautioned that it's not quite that easy. Scientists may have to expand upon the treatment and work with genes to make hair grow properly, he said.