Meanwhile there is something important going on in the fight against baldness.
As in the majority of tissues, the hair follicle has stem cells. There are two types of stem cells that are responsible for the continuous renewal of the follicles. The first type is called active stem cells and they start dividing quite easily. Stem cells of the second type are called quiescent and in case of the new hair growth they don’t start dividing as easily. At the same time, the new hair is based primarily on quiescent cells, which attracted close attention of researchers to these cells. At first people thought that baldness was due to this type of cells.
However, recent studies showed that bald men did have those quiescent cells in their follicles. The problem was that they didn’t divide at all and didn’t contribute to forming new hairs.
This means that even a bald person still has the potential to grow new hair, but because of lack of some regulatory factors quiescent cells can’t start replicating.
Elaine Fuchs was able to identify these regulatory factors in her study published in Cell. Apparently, it’s all about the transit-amplifying cells that are the progeny of the active stem cells.