Miniaturized human hair follicle shows concentration of Prostaglandin D2 (in green). Credit: Garza and Cotsarelis/Penn Medicine
"Although a different prostaglandin was known to increase hair growth, our findings were unexpected, as prostaglandins haven't been thought about in relation to hair loss, yet it made sense that there was an inhibitor of hair growth, based on our earlier work looking at hair follicle stem cells," said George Cotsarelis, MD, chair and professor of Dermatology, and senior author on the studies. In a Penn study published in the Journal of Clinical Investigation last year, underlying hair follicle stem cells were found intact, suggesting that the scalp was lacking an activator or something was inhibiting hair follicle growth.
Prostaglandins are well characterized for their role in many bodily functions — controlling cell growth, constricting and dilating smooth muscle tissue — and a different prostaglandin (F2alpha) is known to increase hair growth. Researchers found that as PGD2 inhibits hair growth, other prostaglandins work in opposition, enhancing and regulating the speed of hair growth.