Hair loss related to cells turning to skin instead of repairing damage

554If your hair line is receding, you have a bald spot or your hair is simply thinner than it used to be, 'confused' stem cells may be to blame. Stem cells in the scalp - the blank templates that can mature into different types of cell – sit quietly in the hair follicles until they are needed.

Now scientists have discovered that the stock of cells which the body has lined up to become hair-producing follicles may turn into skin instead.

It is this on-off cycle of activity which makes the cells so useful for scientists to study. Scientists studied the cycle of regeneration in ageing mice. They found that as the cells age, the wear and tear of ageing leads to errors building up in the mouse's DNA.

This age-related damage, which affects us all, in turn destroys a specific collagen protein. As the collagen is destroyed it sets of signals in the stem cells causing them to switch track in their development. So instead of maturing into hair-producing follicle cells, they mature into skin cells called epidermal keratocytes.

These new skin cells then move out of the follicle to the surface of the scalp, where they are shed in the normal turnover of skin. However, they are not replaced and so the hair follicle shrinks, becoming smaller and smaller until it eventually disappears and becomes part of the surrounding skin.