As a result of research that the occurrence of gray hair is caused by 'stuck' of stem cells, it is possible to return to black hair if the movement function of cells is restored

Losing hair color and turning white is a problem for gray-haired people. Experiments in which the hair follicles were forced to age by repeatedly plucking mouse hair revealed that pigment-producing cells have the unique ability to repeat maturation and rejuvenation while moving through the hair follicles. The mechanism by which hair turns gray due to hair loss has been clarified.

Dedifferentiation maintains melanocyte stem cells in a dynamic niche |

Study Links 'Stuck' Stem Cells to Hair Turning Gray | NYU Langone News

Scientists May Have Finally Worked Out Why Hair Turns Gray – And Possibly How to Stop It : ScienceAlert

It has long been known that the cause of gray hair is a lack of special pigment cells called 'melanocytes'. But I didn't know why I was deficient in this and what I could do to prevent my hair from turning gray.

A research team at New York University, which began to elucidate this problem, first focused on cells called `` melanocyte stem cells ''. According to the research team, this melanocyte stem cell plays a role in supplying melanocytes to hair follicles where hair is growing and coloring the hair. Melanocyte stem cells wait in the hair follicle bulge at the top of the hair follicle while the hair is growing, but after the hair falls out and new hair begins to grow, they move to the growth compartment again. supplies melanocytes.

by Ueno, M., Aoto, T., Mohri, Y., Yokozeki, H. and Nishimura, EK (2014)

As a result of experiments in which the research team forced the hair of the mouse to grow back many times and forcedly aged, it was confirmed that the number of melanocyte stem cells stuck in the hair follicle bulge increased. When melanocyte stem cells lose motility due to aging and become unable to move from within the hair follicle bulge, they become unable to supply melanocytes to growing hair, which causes gray hair.

On the other hand, the melanocyte stem cells, which continued to shuttle between the hair follicle bulge and the dermal papilla, were able to maintain their ability to regenerate, mature into melanocytes, and produce pigment for the two-year lifespan of mice. rice field.

Regarding the results of this mouse experiment, Qi Sun of the research team said, ``This deepens the basic understanding of how melanocyte stem cells color hair.The position of melanocyte stem cells is fixed. It is possible that this phenomenon also exists in humans, and if so, it may restore or prevent gray hair in humans by helping stranded cells to relocate between the developing hair follicle compartments. It showed the possibility of being able to do it.'

The following shows how pink melanocyte stem cells change from resting phase (left) to early growth phase (right).

This research also revealed that melanocyte stem cells have a special ability to return to stem cells after differentiating into TA cells (transit-amplifying cells) in the process of producing melanocytes.

TA cells are an intermediate state between melanocytes and melanocyte stem cells, but normal stem cells cannot return to their original state once they become TA cells. On the other hand, melanocyte stem cells can move between stem cells and TA cells by being exposed to various signal proteins in the process of moving through the developing hair follicle. However, melanocyte stem cells that are stuck in the follicle bulge are cut off from this cycle and are unable to supply melanocytes.

The ability to migrate in response to hair development is unique to melanocyte stem cells. For example, hair follicle stem cells that grow hair can migrate to hair follicle cells without migration, so even if melanocyte stem cells are gone, new hair, that is, gray hair can be grown.

Mayumi Ito of New York University's Grossmann School of Medicine, who is in charge of the research, said, ``It is thought that the cause of gray hair growth and hair color loss is the loss of the chameleon-like function of melanocyte stem cells. suggests that melanocyte stem cell motility and reversible differentiation are key to maintaining hair health and color.'