Circular hair loss: hair follicles kissed awake

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MunichCircular hair loss affects around 1 to 1.5 million people in Germany. Treatment has been difficult so far. That could change: A well-known active ingredient makes the hair sprout again.

Circular hair loss is easy to identify: the hairless, mostly coin-sized areas on the back of the head or on the sides can hardly be overlooked. Partial hair loss is due to an autoimmune reaction in which the body's immune cells target the hair follicles, i.e. the hair's formation centers. In response, the hair goes out and the follicles fall into a kind of deep sleep.

New-old class of active ingredients

It is precisely this mechanism that Raphael Clynes and his colleagues at Columbia University Medical Center were able to decipher in more detail. As they found out in experiments with cell cultures and mice, “alarm” messenger substances trigger a very complex signal cascade, at the end of which the immune cells do their destructive work on the hair roots. At the same time, this chain of messengers gave the researchers the idea of ​​how the hair follicles could be “kissed awake” again from their resting pause.

Magnificent coat

They promised help from a class of active substances called JAK inhibitors, which specifically block certain enzymes (Janus kinases) in this chain. The advantage: there are already drugs (ruxolitinib and tofacitinib) that have been tested in studies and approved for humans. The animal experiments showed resounding success - mice with the hair disease grew magnificent fur again on the affected parts of the body within twelve weeks. Even after the end of the therapy, the hair was retained - so the relapses typical of this disease did not occur.

The researchers then test the new therapy in a small study on humans. The three subjects suffered from moderate to severe hair loss at the start of the study. That is, at least 30 percent of the scalp hair had fallen out. After four to five months of treatment with ruxolitinib, the hair on the head had completely grown back. In addition, attacking immune cells could no longer be detected in the scalp.

“Of course we have to do more tests,” says Clynes, in order to define the framework conditions for a treatment as precisely as possible. But their approach offers an exciting new therapy option to treat circular hair loss. And that relatively quickly, as the active ingredients already help people with other diseases and thus the clinical trials do not take as long as with completely new drugs.

100 a day is normal

It is actually quite normal for people to lose hair. It can be up to 100 pieces per day. It is only when more hair goes out that one speaks of pathological hair loss. The disease can occur at any age. The hair on the head is usually affected, but facial hair or hair on other parts of the body can also fall out. (lh)

Source: Luzhou Xing et al. Alopecia areata is driven by cytotoxic T lymphocytes and is reversed by JAK inhibition. Nature Medicine, 2014; DOI: 10.1038 / nm.3645

Tags:  organ systems skin anatomy