Patches of hair may be gone in many men, but the stem cells that make hair are still there. This unexpected finding is raising hopes of a cure for baldness.
By comparing bald and hairy patches in scalp samples from 54 men undergoing restoration treatments, George Cotsarelis at the University of Pennsylvania School of Medicine in Philadelphia and colleagues discovered that although both had similar numbers of stem cells, most of those in the bald patches fail to develop to the next stage.
In samples from the same individuals, stem cells that had matured into so-called “progenitor cells” were 10 to 100 times as abundant on hairy patches as on bald ones, suggesting they are the key to hair growth.
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