Art by AnMei Little.
Have you ever noticed that politicians and CEOs develop grey hairs fairly quickly? Usually the growth of grey or white hairs accompanies old age due to the natural depletion of melanocyte stem cells (MeSCs), which are responsible for the hair pigmentation. A recent study by Ya-Chieh Hsu’s lab at the Harvard Stem Cell Institute discovered that acute stress caused mice to develop grey hairs by the same process as aging: MeSC depletion. This could explain the premature greying of politicians, CEOs, and others who experience stress on a daily basis.
In their experiment, the researchers stimulated stress in mice by injecting them with a chemical called resiniferatoxin (RTX). RTX acts similarly to the compound in chili peppers that is responsible for the burning sensation of spice. In response to this stressor, the researchers observed that the sympathetic nervous system in mice became overstimulated and activated a “fight-or-flight” response, releasing a neurotransmitter called noradrenaline. Noradrenaline caused MeSCs to multiply and migrate, depleting the reservoir and leading to premature greying. Interestingly enough, if noradrenaline release was blocked, the mice’s hair did not lose color. This suggests that noradrenaline is associated with, perhaps even necessary for, the mechanism for hair greying.
While it may sound like bad news that your stress spawns grey hairs, scientists are deeply interested in further exploring the mechanisms of MeSC depletion. Future research may well discover a way to prevent both stress-induced and age-induced greying. To the next generation of politicians and leaders: do not fret—the era of hair dye might pass soon.
Zhang, B., Ma, S., Rachmin, I., He, M., Baral, P., Choi, S., Gonçalves, W. A., Shwartz, Y., Fast, E. M., Su, Y., Zon, L. I., Regev, A., Buenrostro, J. D., Cunha, T. M., Chiu, I. M., Fisher, D. E., & Hsu, Y.-C. (2020). Hyperactivation of sympathetic nerves drives depletion of melanocyte stem cells. Nature, 577(7792), 676–681. https://doi.org/10.1038/s41586-020-1935-3