Science is full of stories in which great discoveries are made by accident: the discovery of radiation, the discovery of the universe’s shape through x-ray detection, and…the cure for hair loss?
At the time they returned to the cages to find that their bald mice had miraculously grown their hair back, the scientists at UCLA had no intention of curing baldness. Originally, theirs was in fact a study aimed at reducing the harmful affects of chronic stress. The unanticipated side effect of their treatment could prove a boon to balding men and women everywhere, not to mention to the drug company that delivers the cure to them.
Stress is beneficial in small doses, heightening our ability to run away from predators or to concentrate while taking an exam. But chronic stress can bring about an array of mental or physical disorders such as high blood pressure, anxiety disorders, rheumatic diseases, muscle pain, a weakened immune system and neurodegenerative diseases. Chronic stress also causes our hair to fall out.
The UCLA team, led by Yvette Taché, was investigating the role of corticotropin-releasing factor (CRF) in the stress. Corticotropin-releasing factor (CRF) is one of a number of hormones that mediate the body's stress response. Secreted from the hypothalamus, CRF acts at various sites in the brain and other parts of the body to mediate the stress response. In the gut, CRF stimulates a colonic stress response that includes motility, defecation, and diarrhea. But animal models of high anxiety show that elevated CRF can exacerbate irritable bowel syndrome. Trying to find a way to block these effects, Tache's team employed a mouse genetically altered to produce abnormally high levels of CRF. These mice always lost their hair (row A in figure), initially a side effect of little importance to the researchers. In an effort to allay the harmful effects of elevated CRF Tache's team injected the CRF-overexpressing mice with CRF blockers. They injected the mice once a day for five days then put them back in their cages. Three months later they returned to the cages to find that the once-bald mice had grown their hair back (row C). Surprised, the researchers actually thought that someone had mixed up the mice. But going back to the records confirmed that these were indeed the same CRF-overexpressing mice. So then they repeated the experiment and again turned bald mice into mice with backs of lush, full hair convincing to the touch, ready to step out into the field with a newly found confidence. The effect was fast, too. Row B is a picture of mice just 3 days following the final injection.
Hair follicles express receptors for CRF. Over-activating the receptors leads to follicle atrophy: the hair stops growing and eventually falls out. The exciting news for the hairline challenged is that blocking CRF actually reversed the atrophy and the mice regrew all of their hair back, a feat that both Rogaine or Propecia––the leading pharmaceutical hair loss treatments––do moderately well. In addition to the amazing amount of regrowth observed in this study, an added benefit might be the duration of the CRF blocker effects. After only five days of injections, hair regrowth lasted for over four months. In contrast, both Rogaine and Propecia require daily treatments, and stopping treatments will result in any hair gained to be lost.
So when will CRF blockers hit drug store shelves across the world? Significant validation needs to first be performed. For one, hair loss can be brought on by a number of factors. Propecia works by inhibiting the production of a different hormone (dihidrotestosterone) and, although we know it's a vasodilator, the mechanism of Rogaine's actions remain unclear. The findings in the current study are limited in their application as this study models hair loss related to stress and thus may not be relevant to hair loss brought on by factors other than stress. Another limitation is that the study was performed in mice and it remains to be seen if the impressive results can be reproduced in humans.
Unless you’ve actually lost hair, I think it’s hard to imagine the anxiety felt by many who have. Our hair affects our confidence, how we’re treated by others, dating success, it may even affect our ability to climb the corporate ladder. Forty percent of men will have lost a noticeable amount of hair by the time they're 35, 65% of them by the time they're 60. And hair loss isn’t a problem just for men, 40% of people in the U.S. suffering from hair loss are women. Given these statistics, it’s not surprising that the worldwide hair loss treatment industry is big business. Hair transplantation––using healthy follicles from other parts of the body to replace atrophied ones on the scalp––is actually the best treatment available, but it’s invasive and, for many, too expensive. I’d be very surprised if Dr. Taché hasn’t already been contacted by industry reps eager to get a jump on this potential new treatment target.
Rather than marching steadily forward down a path blazed by brilliant hypotheses, science so often moves forward in awkward, accidental steps. Indeed, accidental findings are part of what makes research so exciting, and Taché’s group of stress-turned-hair loss researchers are only continuing this tradition of unpredictability in the area of hair loss treatments. Both Propecia and Rogaine (generic drugs finasteride and minoxidil, respectively) were originally approved to treat conditions other than hair loss: Propecia for enlarged prostates and Rogaine for high blood pressure. In both cases the drug companies noticed the “interesting” side effect of hair growth, and poof: two drugs for the price of one (Merke’s story behind finasteride is an interesting one, beginning with a scientific study of a male pseudohermaphrodites in a remote Carribean village).
Scan the numerous hair treatment forums online and you’ll see just how badly many bald and balding people want a cure. Stem cells represent a promising area for the future of hair loss treatments, either by stimulating stem cells in atrophied follicles or transplanting active stem cells from other areas of the body. But research in this area is in its early stages and stem cell treatments are still a few years off yet. Given the limited effectiveness of current therapies, the hype surrounding the current study is understandable. Women with hair loss may be especially eager to follow up on the UCLA study, as their treatment options are limited compared to men’s due to harmful hormonal affects. Of course, not everyone’s worried about losing their hair. For the Vin Diesel’s of the world, hair is the affliction and it’s easily cured with a pair of ten dollar clippers. For the Woody Allen’s of the world, however, there’s still a lot of work to be done.