Although male pattern baldness affects some 80% of Caucasian men by age 70, it’s remained a puzzle to scientists. Existing treatments were discovered by chance: Rogaine was originally a drug for high-blood pressure and Propecia was for prostate enlargement. In a new study, however, researchers have identified a molecule called Prostaglandin D2 (PGD2) that inhibits hair growth in men, which could provide a target for future drugs designed to treat baldness.
The first thing researchers did was find a good use for the scalp fragments, usually discarded, from men undergoing hair transplant surgery. (Well, where else do you find volunteers to get scalped?) Comparing bald and non-bald tissue from these scalp parts, they discovered that the bald scalp had ten times as much PGD2 and elevated levels of PTGDS, the enzyme that makes PGD2, compared to normal scalp. The gene for PTGDS is also expressed more when there’s lots of testosterone floating around, which may explain why baldness is so endemic to men.
It was a stroke of serendipity that may one day help those who hide under comb overs or wear wigs: scientists studying how mice bowels react to a stress-reducing chemical have inadvertently discovered a cure to baldness. But unfortunately, it looks like this cure won’t apply to genetic baldness, which is by far the main cause of most hairless pates. Still, researchers hope the lucky find will eventually be used to battle at least some of the bare heads of humans.
The story begins with mice that were genetically modified to produce too much corticotrophin-releasing factor, or CRF–a type of stress hormone. Normally, as these stressed-out rodents age, their backs lose hair. But a group of researchers from the Veterans Administration and the University of California at Los Angeles didn’t care about hair, they just wanted to study the effects of a chemical on the modified mice.
Researchers at the Salk Institute developed a peptide called “astressin-B”, which blocks the action of CRF, and the teams injected the peptide into the bald mice. They weren’t thinking about baldness at all — they wanted to test whether the astressin had any impact on the mice’s gastrointestinal tracts. The first injection did nothing, so the team gave the mice additional injections over five days, and then measured the effects on the newly de-stressed mice’s colons. [Popular Science]
With most of the experiment done, the researchers forgot about the mice for three months. Then they returned for some follow-up tests:
Researchers have discovered the gene that determines the baldness of several hairless dog breeds, and say it may offers new insight into the development of skin and hair in other animals – including humans [New Scientist].
Mexican hairless, Peruvian hairless and Chinese crested dog breeds all share the same mutation, researchers say, which probably appeared about 4,000 years ago in Mexican hairless dogs and eventually passed through breeding into the other two dog breeds, Leeb says. “It’s extremely improbable that an identical mutation would have arisen three times,” he says [Science News].