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Stress has far-reaching effects on the human body, including increased risk of chronic disease and other conditions associated with aging. Anecdotal reports suggest that stress can contribute to the premature graying of hair. Findings from a recent study in mice suggest that acute stress depletes melanocyte stem cell populations to promote the graying of hair.
Melanocyte stem cells are undifferentiated cells found in the region of hair associated with growth. They give rise to melanocytes, the mature, melanin-forming cells that provide color to growing hair.
Both mental and physical stress activate the body’s sympathetic nervous system, one of the two main divisions of the autonomic nervous system (the other being the parasympathetic nervous system). The sympathetic nervous system’s primary purpose is to stimulate the body’s fight-or-flight response to stress. A critical element in this response is noradrenaline, a type of hormone and neurotransmitter that plays a role in vigilance and conditioned fear.
The authors of the study induced acute stress in mice and noted that the mice exhibited increased numbers of gray hairs. This increased graying was attributed to the activation of sympathetic nerves in the region in which the stem cells reside and subsequent release of noradrenaline, which promoted stem cell proliferation, differentiation, migration, and eventual depletion.
These findings suggest that neuronal activity induced by an acute stressor can drive stem cell loss and illustrate how overall mental and physical health influence stem cell health.