Stem cells escaping from the hair bulb. In a nutshell, this is more or less the reason why you lose part of your hair as you age. A non-trivial discovery, so much so that it was published in the magazine Nature Aging, which has taken the place of the generally accepted hypothesis that over time hair no longer grows simply because the cells in the hair bulb become depleted and die.
As the experts who conducted the study (on elderly animals, not humans) write, the research sheds light a hitherto unknown activity epithelial stem cells escaping from their niche. And the identification of these “homeless” cells, that is, without a roof, provides new opportunities to understand and study the diseases associated with aging.
How does hair grow?
Stem cells play a crucial role in hair growth, in both mice and humans. THE hair follicles, small tunnel-shaped coves from which hair grows, cross cyclical periods of growth thanks to the action of stamina cells that contain. Stem cells give rise to the hair shaft and its sheath. After a certain period of time, which is short for the hair and much longer for the hair on the head, the follicle becomes inactive and its lower part degenerates. The hair shaft stops growing and the hair falls out, but only to be replaced by a new strand as soon as the cycle begins again. In fact, even if the follicle is inactivated and dies, there remains a supply of stem cells ready to give life to new hair.
Cells that run away
As mentioned, it has always been assumed that stem cells die with age, blocking hair regrowth. Experts from the study of Natureinstead, they have long observed the growth of individual hair follicles in ears of mice. And what they saw was a surprise. As the animals began to age, turn gray and lose their “hair,” their stem cells began to escape out of their hair follicles.
Our body is a car, the mechanics’ cells
The The New York Times to comment on this study and explain in a simple way what happens to our hair as we age, he used an effective metaphor. The body is like a car: if you run it for a long time without replacing the parts, the parts wear out. Stem cells, on the other hand, are like a mechanic and provide replacement parts. In some organs, such as hair, blood, and bone, the replacement is continuous. But in the hair, it seems that as we get older the mechanic decide to leave within a day, leaving us without spare parts.
Research on aging
Beyond the curiosity of why you start losing your hair over time, the study of Nature adds a important piece of knowledge on aging. And above all it provides interesting data to those who do Research on methods to combat disturbances that distinguish this phase of life.