Why does hair turn gray? A new study says ‘stuck’ stem cells may be the cause : NPR

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A new study has found that trapped stem cells may be the reason some aging hair turns gray.

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Gary John Norman/Getty Images

A new study has found that trapped stem cells may be the reason some aging hair turns gray.

Gary John Norman/Getty Images

Have you ever wondered why your hair turns gray as you age? A team of researchers say they have identified the root cause as trapped stem cells – and that means new tips for naturally removing gray from your mane may be coming soon.

It all starts with a type of stem cell called a melanocytealso known as McSCs, the study says, which was published in the journal Nature this week.

The research team from NYU Grossman School of Medicine he was already familiar with melanocytes. They are the main mechanism that produces the pigment melanin, which brings color to your skin and eyes.

That melanin is essential for hair color. McSCs hang out in your hair follicles, where they receive a protein signal that tells them when to become mature cells. The mature cells release the pigment and, voilà, you have your hair color.

But during this study, researchers learned that MCSCs actually move between the microscopic compartments in your hair follicle. Each compartment can give the MsSC a slightly different protein signal, allowing the cell to oscillate between different levels of maturity. This is largely different from how other stem cells operate – ie, they mature until they die.

The unique level of maturity of MsSCs becomes more complicated the older it gets. As your hair grows and sheds in cycles, the more McSCs get stuck in one particular compartment called the swelling of the hair follicle.

The swollen follicle is not giving those McSCs the signal to mature, and it is not sending the McSCs back into a compartment that it would. The jammed cells allow the hair to continue growing, but the hair is not given its dose of pigmentation. As a result, you go gray.

To prove this concept, the research team produced salt and pepper colored mice by physically cutting out pieces of their hair again and again over the course of two years.

They found that the number of McSCs presented in the swelling follicle increased from 15 percent to almost 50 percent. But in the smaller hairs, which were not plucked, the MCSCs continued to move around the different compartments, picking up protein signals and consistently producing a rich brown pigment.

To be clear, McSCs aren’t the only factor that determines when your gray hair grows in. Dr. Jenna Lester, a dermatologist and professor at the University of California, San Francisco, told NPR’s Short Wave podcast that there are a multitude of factors beyond aging that play a role.

“Some people think that sun exposure can damage their melanocytes more or less,” she said. “And hormones also play into it too.” Then there’s stress, genetics and certain medical conditions, all of which can strip hair of its richer hue.

Overall, 74% of people between the ages of 45 and 65 have at least a few silver linings, according to research from the National Institutes of Health.

If you are in that camp and resent it, this new study may be a reason to celebrate: Researchers say that the transfer of McSCs to their proper place can prevent graying.

And anyone who is fooled by the vanity of stress on silver branches can also rejoice: Researchers also say that such studies are putting us one step closer to curing cancer. (Seriously.)

“We are interested in how the stem cells that reside in our body are regulated to maintain our body properly and how they can reform tissues when they are lost from injuries,” said Mayumi Ito, a professor at NYU Langone Health and senior investigator on the study.

“When the regulation of stem cells goes wrong, we have various health problems including cancer,” she told NPR. “The melanocyte stem cell system is advantageous for understanding this broad issue in medical science, as the system’s damage is so visible.”

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