With age gray hair arrives, but also with stress. we’ve seen it within the hair of President Pedro Sánchez, as we saw in his day in Felipe González or more clearly within the case of Barack Obama within the us . But science had not proven it yet.
Now, researchers at Harvard University have confirmed that stress produces gray hair and that they have discovered how that graying of hair occurs. The study reveals the connection between the systema nervosum and therefore the stem cells that regenerate the follicle pigment.
What happens is that stress activates the nerves that are a part of the fight or flight response, which successively causes permanent damage to the pigment regenerating stem cells within the hair follicles. this is often what explains the study published within the journal Nature.
The researchers focused on the sympathetic systema nervosum , which is liable for the fight or flight response of the body. The sympathetic nerves branch into each follicle of the skin. they found that stress causes these nerves to release the chemical norepinephrine, which is absorbed by nearby pigment regenerating stem cells.
«Acute stress causes permanent depletion of stem cells»
In the follicle, certain stem cells act as a reservoir of pigment producing cells. When the hair regenerates, a number of the stem cells become pigment producing cells that dye the hair. The researchers found that norepinephrine from sympathetic nerves causes stem cells to become excessively activated. All stem cells become pigment producing cells, prematurely depleting the reservoir.
“After a couple of days, all the stem cells that regenerate the pigment were lost. Once they’re gone, the pigment can not be regenerated. The damage is permanent, ”explains lead author Ya-Chieh Hsu, professor of Stem Cells and Regenerative Biology at Alvin and Esta Star at Harvard.
“Acute stress, particularly the fight or flight response, has traditionally been considered beneficial for the survival of an animal. But during this case, acute stress causes permanent depletion of stem cells, ”adds Bing Zhang, another of the study’s authors.
Stress damages the follicle stem cells
Ten years ago, Japanese scientists at the University of Kanazawa have already seen that stress is effectively ready to turn white hair through the damage it causes within the stem cells of hair follicles.
In their case they observed that the type of gen genotoxic stress ’that damages DNA depletes the stem cells of the follicle melanocytes that are liable for producing these pigment producing cells. rather than disappearing, these stem cells differentiate into mature melanocytes.