According to a recent study, the graying of hair is connected to the inability of stem cells to produce color in new hair growth. Stem cells move between different compartments, but if they become stuck in one compartment, they are unable to develop into pigment cells. If the mobility of these cells can be restored, it could lead to the restoration of pigment production, ultimately preventing the occurrence of gray hair.
A recent study, led by researchers from New York University’s Grossman School of Medicine and published in the journal Nature, has revealed that melanocyte stem cells (McSCs) can become stuck in place, leading to the development of gray hair. The study used mice as research subjects and found that in a healthy situation, McSCs move between different compartments of developing hair follicles. This allows the cells to mature and acquire the protein necessary to develop into pigment cells, which continuously color the hair as it grows. The mobility of the McSCs between compartments is a unique aspect of these cells, which shift back and forth between maturity levels over time.
However, the study found that in certain cases, the McSCs can become trapped in the hair follicle bulge compartment, preventing them from returning to the germ compartment. This is where WNT proteins promote the regeneration of the cells into pigment cells. If the cells remain stuck, no pigment cells can be produced, resulting in gray hair.
According to Mayumi Ito, a senior investigator and professor at NYU Langone Health, this loss of mobility in melanocyte stem cells is likely the cause of graying and hair color loss. The study suggests that the key to maintaining healthy, colored hair is maintaining the mobility and reversible differentiation of these cells.
In essence, if we can keep the McSCs moving, or find a way to encourage them to regain mobility if they become stuck, we could potentially see more vibrant and colorful heads of hair around the world.
In a news release, Qi Sun, a postdoctoral fellow at NYU Langone Health, stated that the study provides a better understanding of how melanocyte stem cells work to color hair. The newly discovered mechanisms raise the possibility that fixed positioning of melanocyte stem cells may exist in humans, which could lead to potential pathways for reversing or preventing gray hair by helping stuck cells to move between developing hair follicle compartments again.
Sun noted that McSCs specialize in pigment production and are distinct from the cells responsible for hair growth. This means that hair can continue growing even without pigment. The study conducted by NYU showed that as the hair regrowth process progresses, the number of McSCs lodged in the follicle bulge compartment increases. At some point, this non-pigment-producing follicle bulge contains about 50 percent of all McSCs.