• Log in with Facebook Log in with Twitter Log In with Google      Sign In    
  • Create Account
  LongeCity
              Advocacy & Research for Unlimited Lifespans

Photo

A Broad and Reversible Threshold for Hair Greying


  • Please log in to reply
No replies to this topic

#1 reason

  • Guardian Reason
  • 1,101 posts
  • 241
  • Location:US

Posted 02 July 2021 - 10:19 AM


This research into the fine details of hair greying is interesting but of limited practical application, I suspect. It is nonetheless a good illustration of the point that there are few sharp dividing lines in the biochemistry of aging. Even seemingly binary changes such as hair going grey represent a broad threshold that is crossed slowly, and under the hood there are likely numerous competing and conflicting mechanisms and regulatory systems that only incrementally come to a consensus on cell behavior. None of this really changes the best way forward for the treatment of any part of aging: identify the causative damage and repair that damage, in the expectation that many of the consequences that make up degenerative aging will reverse themselves as cell behavior returns to a youthful state.

Hair greying is a visible sign of aging that affects everyone. The loss of hair color is due to the loss of melanin, a pigment found in the skin, eyes and hair. Research in mice suggests stress may accelerate hair greying, but there is no definitive research on this in humans. This is because there are no research tools to precisely map stress and hair color over time. But, just like tree rings hold information about past decades, and rocks hold information about past centuries, hairs hold information about past months and years.

Hair growth is an active process that happens under the skin inside hair follicles. It demands lots of energy, supplied by structures inside cells called mitochondria. While hairs are growing, cells receive chemical and electrical signals from inside the body, including stress hormones. It is possible that these exposures change proteins and other molecules laid down in the growing hair shaft. As the hair grows out of the scalp, it hardens, preserving these molecules into a stable form. This preservation is visible as patterns of pigmentation. Examining single-hairs and matching the patterns to life events could allow researchers to look back in time through a person's biological history.

Researchers here report a new way to digitize and measure small changes in color along single human hairs. This method revealed that some white hairs naturally regain their color, something that had not been reported in a cohort of healthy individuals before. Aligning the hair pigmentation patterns with recent reports of stress in the hair donors' lives showed striking associations. When one donor reported an increase in stress, a hair lost its pigment. When the donor reported a reduction in stress, the same hair regained its pigment. Researchers mapped hundreds of proteins inside the hairs to show that white hairs contained more proteins linked to mitochondria and energy use. This suggests that metabolism and mitochondria may play a role in hair greying.

The new method for measuring small changes in hair coloring opens up the possibility of using hair pigmentation patterns like tree rings. This could track the influence of past life events on human biology. In the future, monitoring hair pigmentation patterns could provide a way to trace the effectiveness of treatments aimed at reducing stress or slowing the aging process. Understanding how 'old' white hairs regain their 'young' pigmented state could also reveal new information about the malleability of human aging more generally.

Link: https://doi.org/10.7554/eLife.67437


View the full article at FightAging




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users