A study has discovered that molecular signals from stem cells within the skin's fatty layer have the capability to trigger hair growth, and the finding could lead to new treatments for baldness.
Yale researchers were able to identify these cells, which are necessary to spur hair growth in mice.
"If we can get these fat cells in the skin to talk to the dormant stem cells at the base of hair follicles, we might be able to get hair to grow again," said Valerie Horsley, assistant professor of molecular, cellular and developmental biology and senior author of the paper.
Men with male pattern baldness still have stem cells in follicle roots but these stem cells lose the ability to jump-start hair regeneration.
Scientists have known that these follicle stem cells need signals from within the skin to grow hair, but the source of those signals has been unclear.
Horsley's team observed that when hair dies, the layer of fat in the scalp that comprises most of the skin's thickness shrinks. When hair growth begins, the fat layer expands in a process called adipogenesis.
Researchers found that a type of stem cell involved in creation of new fat cells - adipose precursor cells - was required for hair regeneration in mice.
They also found these cells produce molecules called PDGF (platelet derived growth factors), which are necessary to produce hair growth.
The findings have been published in the September 2 issue of the journal Cell.