According to a recent study conducted on mice by researchers at NYU Grossman School of Medicine, certain stem cells that can move between growth compartments in hair follicles lose their ability to mature and maintain hair color as people age, which may provide a potential solution to reversing or preventing gray hair.
According to a news release from NYU Grossman School of Medicine and NYU Langone Health, the researchers found that melanocyte stem cells (McSCs) can move between growth compartments of the follicles of hair, but as we get older these become stuck and can no longer mature and maintain hair color, which is determined by nonfunctional pools of these cells within the follicles of hair that produce the protein pigments needed for color.
"Our study adds to our basic understanding of how melanocyte stem cells work to color hair," study lead investigator Qi Sun, Ph.D, a postdoctoral fellow at NYU Langone Health, said in the news release. “The newfound mechanisms raise the possibility that the same fixed-positioning of melanocyte stem cells may exist in humans. If so, it presents a potential pathway for reversing or preventing the graying of human hair by helping jammed cells to move again between developing hair follicle compartments."
According to the news release, researchers found that McSCs can alternate between the primitive cell state and the next level of maturation, termed the transit-amplifying state, depending on their location. The release noted the researchers also found that as people age, an increasing amount of McSCs are ensnared in the bulge of the hair follicle at the base, which is a stem cell compartment.
The researchers noted in the release the cells stay there and cannot mature to the next level and cannot return to the location of their origin in the germ compartment where they regenerate into pigment cells, assisted by WNT proteins.
Moreover, according to the NYU news release, the McSCs demonstrate a unique level of plasticity as compared to other self-regenerating stem cells researchers found in the hair follicle. Despite this pigment loss, the release noted that hair can still grow even with pigment loss.
The release noted the researchers also found WNT is need for the cells to mature and produce pigment, which happens decreasingly in the hair follicle bulge.
The researchers, the release noted, found that in mice aging hair follicles showed a spike in the amount of McSCs stuck in the bulge unable to transfer to mature pigment-producing melanocytes. Those cells that could still move back and forth were still able to produce pigment during the study, according to the news release.
“It is the loss of chameleon-like function in melanocyte stem cells that may be responsible for graying and loss of hair color," Mayumi Ito, a professor at NYU Langone Health, concluded in the news release. “These findings suggest that melanocyte stem cell motility and reversible differentiation are key to keeping hair healthy and colored."
