Grey Hair is the Result of DNA Damage
Credit: Ken Inomata/Kanazawa University
It seems that some Japanese researchers have figured out that genotoxic stress can cause hair follicles to go white, as it were. But it’s not that the stress actually causes the lack of pigmentation, but rather that the stress causes the cells to use up their pigmentation faster than they should, and once the pigment runs out, it’s silver city, baby.
Some years ago, a dermotologist in Japan, Emi Nishimura, discovered that hair follicles are filled with melanocyte stem cells. If you look at the base of that word, melan-, you may associate it with melanin, which gives animals and plants pigment. The melanocyte stem cells hang out in your hair follicle and whenever a new hair starts to grow, some of those stem cells become the melanocytes, or the cells responsible for your hair’s color. Some of the stem cells stay behind, so to speak, waiting for the next strand to come along. Ideally, your body should store enough of these little dabs of color to last your lifetime, but new research shows that stress to the DNA in the cells cause more of the melanocytes to join whatever hair is growing, leaving fewer and fewer color cells behind for the next hair.
Nishimura suspected that genotoxic stressors, such as radiation or harsh chemicals, might play a role in the stem cells’ fate, because they’ve been implicated in other signs of aging. She and colleagues at Japan’s Kanazawa University tested the idea in mice, which also gray with age. After exposure to cell-stressing x-rays or chemotherapy drugs, young mice went gray in an unexpected way. More of their melanocyte stem cells matured into color-producing melanocytes, depleting the store of stem cells. Instead of dying or being inactivated, the DNA-damaged cells matured before their time.
“The mature cells lose their regeneration capabilities,” Nishimura explains. “The mice then can’t produce enough pigment-making cells” and consequently go gray. Moreover, the stressed mice’s gray hairs and the cell populations in their follicles were indistinguishable from those of elderly mice, suggesting that genotoxic stress might drive natural graying as well. –ScienceNOW Daily News
So basically, genotoxic stress — that is anything from ultraviolet light to the natural division of the cell itself — damages your cells’ DNA, but it also leads to the “maturing” as it were. If the cell is mature, it is no longer dividing like cells do. If a cell is not dividing, it’s not reproducing itself. Is this early maturation process a defensive move on the part of damaged cells that shut down their reproductive processes in order to not pass on the damage (DNA defect) to its “children”?
Although, truth be told, I’m sure that this research will be used to prevent grey hair, rather than to prevent cancer. Hey, I’m a cynic.
cells, stem cells, grey hair, gray hair, going grey, DNA, cancer, cell division, cell maturation, melanocyte stem cells, Kanazawa University, Emi Nishimura, mice
