Greying of hairs has been a serious concern among several people across the globe. If you are among those who always wondered about the possible reasons behind it, scientists in the United States have the answer. According to scientists, stem cells that get stuck as people age may be the reason why hairs turn grey.
Scientists of New York University (NYU)- Lagone showed, in a mice study, that certain stem cells have a unique ability to move between growth compartments in hair follicles. But some of them loses their ability to mature and maintain hair colour as people age.
The study has been published in the journal Nature. It focuses on cells in the skin of mice, which are known as melanocyte stem cells or McSCs in humans.
“The study done by our team adds to our basic understanding of how melanocyte stem cells work to colour hair,” said study lead investigator Qi Sun, a postdoctoral fellow at NYU Langone Health.
“What is responsible for greying and loss of hair colour is the disappearance of chameleon-like function in melanocyte stem cells. These findings suggest that in order to keep your hair healthy and coloured, the key factors are melanocyte stem cell motility and reversible differentiation,” said Mayumi Ito, Professor at NYU Langone Health.
Scientists found in the latest experiments that in the mice whose hair was plucked and was physically aged and forced regrowth, the number of hair follicles with McSCs lodged in the follicle bulge increased from 15 per cent before plucking to nearly half after forced ageing.
These cells remained impotent to regenerate or mature into pigment-producing melanocytes.
The scientists found that the stuck McSCs ceased their regenerative behaviour as they were no longer exposed and therefore their ability to produce pigment in new hair follicles, which continued to grow.
By contrast, other McSCs that continued to move back and forth between the follicle bulge and hair germ retained their ability to regenerate as McSCs, mature into melanocytes, and produce pigment over the entire study period of two years.
Ito said the team has plans to investigate means of restoring motility of McSCs or of physically moving them back to their germ compartment, where they can produce pigment.