hypoxia and stem cells

It sounds more like an explanation that would be used by nursery children than respected scientists, but researchers have found that rather than losing their hair altogether, people who are going bald are suffering from "sleeping" hair follicles.

Trichologists have discovered that hair follicles on the scalp can become trapped in a resting state where they do not grow new hair, leading to thinning.

They now claim to have identified a way of waking the follicles up again to help restore a fuller head of hair to people who are going bald.

Unfortunately they may not be able to delay the balding process forever, as eventually the hair follicles lose the ability to make new hair, but for those who are starting to get a bit thin on top, it may help stave of the need for embarrassing wigs, comb overs or hair transplants.

Dr Bruno Bernard, head of hair biology at L'Oreal in Paris who carried out the research, has now announced that the company are developing a new treatment that can be applied to the scalp in a shampoo or cream to help encourage hair to grow again.
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He said: "Hair follicles exist in two stable states – either an active state or a dormant state. From time to time, they will jump from one state to another.

"Some of the follicles are just resting in the dormant state and are waiting for the right signal to make new hair. They are in a latency period. If you can reduce this latency period, you will have more hair.

"We have identified a compound and we are going to make a formulation of it that can be applied to the scalp to wake the follicle up from its sleeping state to the active state."

Up to half of all men suffer from androgenic alopecia, the most common cause of hair loss and thinning in humans. It is estimated that around eight million women in the UK also suffer excessive hair loss to some degree.

Typically hair strands grow continually for a period of up to four years before the follicles switch to a dormant state and the strand of hair falls out. During this dormant period, stem cells in the skin begin the processes needed to grow new hair.

In people who are going bald, however, this process can stall and new hair does not form.

Scientists working with Dr Bernard at L'Oreal believe they have identified why this happens. They have found two reservoirs of stem cells help are responsible for creating new hair, one that is near the surface of the skin and one that is deeper in the layers of the skin.

The bottom reservoir of stem cells, called CD34+ cells, are in an environment that is low in oxygen, known as hypoxia, which helps to keep the stem cells in a healthy condition.

Dr Bernard, who presented the findings at the European Hair Research society in Barcelona, said that in people who are going bald, the levels of oxygen around these stem cells have changed, meaning they work less efficiently and so preventing the creating of new hair.

"The stem cells can sense the amount of oxygen around them," he said. "We have identified molecules that mimic the effect of hypoxia on the stem cells. It means we can push the empty hair follicles to make new hair fibres faster."