Clue to baldness found in skin stem cells of mice

Fat cells may hold the key to triggering hair growth, US researchers have found. They
discovered that a layer of fat cells under the skin of mice sends chemical
messages to stem cells, instructing them to grow hair.

Professor
Valerie Horsley, a lead author on the paper
said: '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'.

Research
showed that when hairs die, the layer of fat underneath them shrinks. When new
hair grows, the layer of fat grows back. By using mice that were unable
to produce these fat cells (and so having stunted hair growth) the scientists from Yale University, USAwere able to study the effect of the fat cells on the mice's ability to grow
fur.

They injected
these mice with fat cells derived from healthy mice, and discovered they
could kick-start fur growth. Two weeks after the injection they
could see hair follicles being reactivated, and the start of new hair growth.

They then
isolated the chemical signal that they believe is responsible for stimulating
hair growth — platelet derived growth factor (PDGF). The fat cells secrete PDGF
at a level roughly 100 times higher than neighbouring cells do, and when the
team injected PDGF directly into bald mice it was able to stimulate hair growth
in 86 percent of follicles.

It has
previously been shown that men suffering from male-pattern baldness still have
the normal amount of stem cells required for hair growth but that these cells
are dormant.

The researchers
hope they may be able to use a similar signal to awaken the dormant stem cells
in balding men, and encourage hair growth. However, further research is needed
to determine if the signals involved in human hair growth are the same as in
mice.

This
research was published in Cell.