Many of the signs of aging are invisible, slow, and subtle. cell division ability, Cardiac output and renal function are not mirrored accurately. But gray hair is his one of the most obvious clues that his body isn’t working the way it used to.
When the stem cells that produce melanin stop working properly, our hair turns gray.New study in mice, but with public impact, published journal wednesdayprovides a clearer picture of the cellular glitches that turn us into silver foxes and vixens.
“This is a really big step in understanding why we get gray hair,” said Mayumi Ito, author of the study and professor of dermatology at New York University’s Grossman School of Medicine.
Unlike embryonic stem cells, which develop into all kinds of different organs, adult stem cells have more defined pathways. Melanocyte stem cells in hair follicles are responsible for producing and maintaining hair pigment.
Each hair follicle stores immature melanocyte stem cells. When they are needed, those cells migrate from one part of the hair follicle to another, where proteins stimulate them to mature into pigment-producing cells, giving the hair its tint.
Scientists believed that gray hair was the result of a depleted pool of melanocyte stem cells. I wondered if the hair would lose its pigment if it was still present.
To learn more about stem cell behavior during different stages of hair growth, researchers spent two years tracking and imaging individual cells in mouse fur. Surprisingly, the stem cells shuttled back and forth within the follicle, transitioned to a mature, pigmented state, and then exited the follicle again.
“We were surprised,” Sun said, noting that seeing one group of stem cells flip back and forth between mature and young states doesn’t fit existing explanations. rice field.
However, over time, the melanocyte cells became unable to maintain the double act. It stops receiving protein signals to make. Since then new hair growth has not gotten the dose of melanin.
The researchers further explored this effect by plucking hairs from mice to simulate a faster hair growth cycle. This “forced aging” caused melanocyte stem cells to build up in storage and stop producing melanin.
Although the study was done in rodents, the researchers say their findings should be related to how human hair gains and loses color. They hope their findings will be a step towards preventing or reversing the progression of gray hair.
Melissa Harris, a biologist at the University of Alabama at Birmingham, said the findings echoed previous evidence she had seen that “not all melanocyte stem cells are created equal, and even if there were some left over.” said to help “harden” the . ”
Since plucked hairs may not behave in the same way as naturally aged hairs, Dr. Harris said the results of the study on “forced aging” of mouse hair “maybe with a little grain of salt.” She said she would accept. Insights into stem cell behavior may help researchers understand cancer, cell regeneration, and more.
“I know some people take hair for granted, but in a way it’s actually easy to see the potential ways aging and other perturbations affect our bodies.”
