Stem cells (hair follicles)

The basis of the hair cycle is that hair growth is split into three distinct stages; Anagen (growth), Catagen (regression) and Telogen (resting). This was previously covered in the post ‘curing baldness’ but here’s a quick recap in the diagram below.

For those of you that require more details i.e. the genetic bit, please follow this link.

The original hypothesis was that our head has millions of hair follicles which are produced when we are at our earliest stage of development; a developing foetus has all of its hair follicles by week 22. It was thought that after the embryo stage, no more follicles could be produced and therefore any hair damage/ loss after this stage would be permanent.

However subsequent research has proved this to be untrue. Studies have found that in actual fact hair follicles stop functioning and lay dormant until reactivated again. But what is it that switches these hair follicles on and off. This it is this part that still remains a bit of a mystery.

New research at the University of Pennsylvania has discovered that the Wnt gene (previously used to help facilitate wound healing) may be involved in making new hair follicles.

In an animal study, a group of mice had a small piece of their epidermis removed to create a wound. These wounds were then monitored very closely and left to heal naturally. The results showed that the combination of Wnt genes with stem cells allowed the wound to heal but also allowed the formation of new hair follicles.

Scientists believe that the appearance of a wound triggered the Wnt gene to switch on the hair follicle in the area surrounding the wound and so kick starting the hair follicles back into action. Further tests showed that if the Wnt gene was off, no new hair follicles were produced. When the Wnt gene was switched on, hair follicles were produced and if the amount of Wnt gene proteins were increased, leading to increased gene activity, then the number of hair follicles also increased.

Future work involves activating/deactivating Wnt genes in a safe manner. So this research may form the basis of future hair therapy? As I mentioned in previous posts, personally I feel it is better to concentrate our efforts of reactivating existing follicles that are currently dormant, as opposed to producing new follicles via stem cells.