Scientists reveal reasons why your hair turns grey

By India Today Health Desk: Scientists have discovered the reason why our hair turns grey and this has a lot to do with pigment-making cells. A new study, published in the journal Nature, suggests that stem cells may get stuck as hair ages and lose their ability to mature and maintain hair colour.

The research focused on cells in the skin of mice and humans, called melanocyte stem cells, or McSCs. The study, led by researchers from New York University Grossman School of Medicine, stated that certain stem cells have a unique ability to move between growth compartments in the hair follicles, but they get stuck as people age.

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When they get stuck, they begin to lose their ability to mature and maintain their hair colour.

Our hair colour is controlled by McSCs, which are nonfunctional but are continually multiplying. The study showed that McSCs are remarkably plastic. This means that during normal hair growth, such cells continually move back and forth on the maturity axis as they transit between compartments of developing hair follicles.

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It is inside these compartments where McSCs are exposed to different levels of maturity-influencing protein signals.

“Our study adds to our basic understanding of how melanocyte stem cells work to colour hair,” said study lead investigator Qi Sun, PhD, a postdoctoral fellow at NYU Langone Health.

Qi Sun pointed out that this study can potentially lead to the possibility of delaying grey hair by moving the stuck cells.

“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 greying of human hair by helping jammed cells to move again between developing hair follicle compartments,” Qi Sun said.

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In the latest experiments done on mice, it was seen that as hair ages, sheds and then repeatedly grows back, increasing numbers of McSCs get stuck in the stem cell compartment called the hair follicle bulge. The McSCs transform between their most primitive stem cell state and the next stage of their maturation depending on their location.

Study senior investigator Mayumi Ito, PhD, a professor in the Ronald O. Perelman Department of Dermatology and Department of Cell Biology at NYU Langone Health said, “These findings suggest that melanocyte stem cell motility and reversible differentiation are key to keeping hair healthy and colored,” said Dr Ito.