Blame Your Gray Hair on Stress
June 16, 2009
(Ivanhoe Newswire) -- Those pesky gray hairs that tend to crop up with age really are signs of stress. Researchers have discovered that the kind of "genotoxic stress" that does damage to DNA depletes the melanocyte stem cells (MSCs) within hair follicles that make pigment-producing cells. Anything that can limit the stress might stop the graying from happening, the researchers said.
"The DNA in cells is under constant attack," Emi Nishimura of Tokyo Medical and Dental University was quoted as saying. "It is estimated that a single cell in mammals can encounter approximately 100,000 DNA damaging events per day. Once stem cells are damaged irreversibly, the damaged stem cells need to be eliminated to maintain the quality of the stem cell pools," Nishimura continued. She says that differentiation might be a more sophisticated way to get rid of those cells than stimulating their death.
"In this study, we discovered that hair graying, the most obvious aging phenotype, can be caused by the genomic damage response through stem cell differentiation, which suggests that physiological hair graying can be triggered by the accumulation of unavoidable DNA damage and DNA-damage response associated with aging through MSC differentiation," Nishimura said.
SOURCE: CELL, June 12, 2009
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