Researchers have identified a biological pathway previously unknown to have a role in male pattern hair loss.
Published today in Science Translational Medicine1, the study finds that a lipid compound called prostaglandin D2 (PGD2) has a role in inhibiting hair growth.
The study “is likely to lead to new hair growth products based on prostaglandin biology,” says Anthony Oro, an epithelial biologist at Stanford University in California, who was not involved in the study.
Male pattern baldness, or androgenetic alopecia (AGA), affects around 80% of men at some point in their lives. Only one predisposing factor — a mutation in a testosterone receptor — has been identified, and it is found in only a minority of men with AGA. Other causes are largely unknown, and present treatments were discovered serendipitously — finasteride (Propecia) was originally prescribed for prostate enlargement, and minoxidil (Rogaine) for hypertension. Their molecular mechanisms are unclear.
To look for other factors involved in AGA, researchers led by George Cotsarelis, a dermatologist at the University of Pennsylvania in Philadelphia, examined gene expression in balding and non-balding scalp tissue from five men with AGA. They found that PGD2 was more abundant in the balding scalp tissue, as was prostaglandin D2 synthase, which catalyses PGD2.
The authors also found that, in mice, PGD2 expression peaks during the hair-growth cycle stage in which the follicle begins regressing. Cultured human follicles and mice treated with PGD2 also had hair growth inhibited