How Does Baldness Start?

How does baldness start?

Hair loss would be due to inactivation of certain stem cells.

Good news for the bald or at least for men who, not necessarily sacrificing to the fashion of the shaved head, live badly their baldness. A recent discovery allows them to hope to see their hair grow back one day!

In a study published in the Journal of Clinical Investigation, researchers from the Department of Dermatology at the University Of Pennsylvania (USA), shows that baldness may be due to the inactivation of stem cells contained in the hair follicles. And that it would be enough to "awaken" them so that these microscopic hair factories are restored to function normally.

To come to this rather surprising conclusion, the team led by George Cotsarelis compared the follicles from the garnished and cleared parts of the skull of men who underwent a capillary transplant.

The US researchers found that the number of stem cells was the same in both cases. In contrast, follicles from the hairy areas contained much more mature or "progenitor" cells than those located in the bald areas. Hence the idea that male pattern baldness would not be linked to the decline in the number of stem cells but rather to the drop in their activity.

At this stage, researchers are unaware of the reasons why the conversion of stem cells into "progeny" cells no longer takes place. A breakdown in hair activity which does not end with the disappearance but with the weakening of the follicles, and with the ultimate production of microscopic hair, hence “Invisible”. "However, the fact that the number of stem cells is not affected gives us hope to add remedy one day the problem of baldness”, explains George Cotsaleris.

Four years ago, his laboratory had shown that the follicles of adult mice were able to regenerate provided that they "woke up" certain active genes during embryonic development. And, the healing of a wound on model mice created an "embryonic window" offering the opportunity to increase the number of new hair follicles.

Finally, in his study published, the team of George Cotsarelis announced to have discovered in mice, a type of "progenitor" cells similar to those of humans; once implanted in immune deficient mice, are capable of making follicles and of re-growing hair.

One of the next steps will now be to identify the biological factors at work in the conversion of stem cells into progenitor cells; A job that will still take years of research.

At present, the treatment of baldness is mainly done by micro grafts of hair taken one by one in the areas lined up towards the parts of the skull. A tedious, long and costly operation. In 80% of the cases, baldness is of hereditary origin and mainly concerns men over 45 years. Recent studies have shown that an area of Chromosome 20 is involved.