How chronic stress triggers hair loss

In March 2021, scientists revealed how chronic stress can keep hair follicles in this inactive state for longer. The hair follicle is one of the few tissues in the body that can regenerate itself, thanks to special cells known as adult stem cells. Researchers at the Harvard Department of Stem Cell and Regenerative Biology in Cambridge, MA, discovered how chronic stress in mice suppresses the activity of these cells. By James Kingsland on November 3, 2022 — Fact checked by Rita Ponce, Ph.D. They showed that a stress hormone called corticosterone — which is the mouse equivalent of cortisol in humans — keeps the follicle stem cells inactive. They found that in the absence of circulating corticosterone, the stem cells underwent many more rounds of regeneration during the animals’ lifetime. By contrast, high levels of the hormone, as a result of chronic stress, kept them inactive for longer and led to fewer rounds of regeneration. Rather than directly affecting the stem cells, however, corticosterone acted on a cluster of cells under the follicle, known as the dermal papilla. The researchers showed that in mice, the stress hormone prevented the dermal papilla from producing a molecular signal called Gas6, which normally activates the follicle stem cells. They reported their findings in NatureTrusted Source. “Under both normal and stress conditions, adding Gas6 was sufficient to activate hair follicle stem cells that were in the resting phase and to promote hair growth,” says Dr. Sekyu Choi, who was the lead author of the study. “In the future, the Gas6 pathway could be exploited for its potential in activating stem cells to promote hair growth,” he adds. The researchers say they will need to conduct more studies in mice before they can explore potential treatments in humans.