Published: Fri, January 24, 2020
Health Care | By Cedric Leonard

Scientists Finally Pin Down Why Stress Turns Our Hair Gray

Scientists Finally Pin Down Why Stress Turns Our Hair Gray

Called melanocyte stem cells, these cells become active when a new hair begins to sprout in the follicle; the melanocyte stem cell then starts to divide and produce pigment-producing cells that color the shaft of the hair as it grows.

Scientists have long understood that gray hair is the result of the natural aging process, certain pigment/follicle disorders, and stress.

It's said that Marie Antoinette's hair turned white the night before she was beheaded during the French Revolution. Suppressing that protein prevented the hair color change, suggesting that a novel treatment for preventing graying may be possible.

Hair graying is one of the many ways that stress exacts a toll on the body. A litany of tests led scientists to discover that the stress-induced loss of melanocyte stem cells is hinged on the "activation of sympathetic nerve fibers", which controls animals' reaction to stress or danger, aka the "fight or flight" response.

"Melanocyte stem cells are also lost during aging", Hsu tells Reuters.

Hsu found that even during normal stress (not the fight-or-flight kind), the sympathetic nervous system is active, and produces the chemical norepinephrine, which leads to increased muscle contraction, including in the heart.

But don't be too quick to touch up those roots: A growing number of people today are OK with going gray. However, when mice lacking immune cells still showed hair graying, researchers turned to the hormone cortisol. When hair regenerates, some of the stem cells convert into pigment-producing cells that color the hair.

"Stress continuously elevates stages of the hormone cortisol within the physique, so we idea that cortisol could well play a process", Hsu acknowledged.

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"Acute stress, critically the warfare-or-flight response, has been traditionally viewed to be purposeful for an animal's survival". "The damage is permanent". In the stressed mice, all of the stem cells differentiated into melanocytes, depleting the pool of stem cells completely within five days.

The damage to the pigment-regenerating cells, she added, is "permanent". "That causes all of the stem cells to be activated, so they convert into pigment-producing cells", she said.

The collaborators included Isaac Chiu, assistant professor of immunology at Harvard Medical School who studies the interplay between nervous and immune systems. "We are interested in finding out the link".

The scientists hope that their research will help illuminate the wider effects of stress on different organs and tissues and clear the path for the creation of drugs that can counter this graying effect. This working out will pave the style for contemporary studies that leer to change or block the unintended effects of stress.

"By understanding precisely how stress affects stem cells that regenerate pigment, we've laid the groundwork for understanding how stress affects other tissues and organs in the body", concludes Hsu. "There is still a lot of work to do in this area".

Senior author Professor Ya-Chieh Hsu, a regenerative biologist at Harvard University chose to undertake experiments in a bid to find out if "the connection is true".

The look changed into once supported by the Smith Family Foundation Odyssey Award, the Pew Charitable Trusts, Harvard Stem Cell Institute, Harvard/MIT Total Neuroscience Grants Program, Harvard FAS and HMS Dean's Award, American Cancer Society, NIH, the Charles A. King Believe Postdoctoral Fellowship Program, and an HSCI junior college grant.

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