Good news for bald mice: A five-day treatment can restore a silky black coat of fur. But it will be a while before the hair-raising drug -- accidently discovered by University of California, Los Angeles scientists studying gut function -- is ready to be tested in humans.
Although baldness and graying have long been linked to stress, digestive disease researcher Dr. Mulugeta Million had no idea that inhibiting key receptors in a stress response pathway would have such a dramatic effect on hair.
"This was totally unexpected," said Million, a veterinarian and co-director of the UCLA/CURE Digestive Diseases Research Center. "We do not work on hair; we did not set out to study hair growth."
Million and colleagues were studying gut function in mice that happened to have alopecia -- hair loss -- because of an increase in corticotropin-releasing factor (CRF), a compound that seems to play a role in how the body responds to stress. When they injected an antagonist -- a compound that blocks CRF -- once daily for five days, the mice re-grew hair. It was an effect that held up for four months.
"We weren't prepared to see anything like that," Million said.
The antagonist beat out the commercial treatment for alopecia, Rogaine, which caused "moderate" hair re-growth, Million and colleagues reported in the Feb. 17 edition of the online journal PLoS One.
The authors suggest that temporarily blocking CRF receptors could be "a breakthrough therapy for alopecia," and might also hold potential for male pattern baldness and hair loss due to chemotherapy.
"What we can reasonably say is that the antagonist initiates the hair cycle," Million said. "In bald individuals, and in these mice, the hair follicles are in a resting stage. The antagonist awakes them. It turns on the cycle, and the growing phase starts."
The treatment not only reversed hair loss, it also prevented it if started ahead of time. It also restored pigmentation in the skin -- an effect Million said might prevent graying too.
Million now plans to tease out how the drug works, and hopes to find a way to send it specifically to hair follicles to reduce the potential for side effects.
"Stress is a very general response, and whether this antagonist could act in other parts of body where stress is also observed is unclear," he said. "The hope is -- and it is possible -- to design a molecule that will act specifically in the skin and won't interfere with other systems."
Once that can be demonstrated, Million said he will take the accidental treatment into clinical trials.
"We're at the early stage, and obviously we need to do more work to understand how this works, where it acts and, of course, if it has side effects," he said. "But we're excited because the effects are very dramatic, very quick, and last for so long."