CAMBRIDGE, Mass. — A scientific discovery may make the “comb over” a thing of the past for people losing their hair. Harvard researchers say a baldness cure is on the horizon after scientists uncovered a protein that fuels hair growth.
The breakthrough could lead to a cream that fuels an unlimited supply of locks for the follicly-challenged — a true baldness cure, rather than a temporary fix. In experiments, mice successfully sprouted three times as many hairs by surgically removing their adrenal glands. The small organs above each kidney release the stress hormone corticosterone, the rodent equivalent of cortisol. This stops the protein GAS6 in its tracks.
Stress reactions such as worry, anger, and anxiety have long been connected to male pattern baldness. Researchers even estimate about a quarter of COVID-19 survivors suffer hair loss due to the shock of infection.
“Stress hormones suppress growth in mice through the regulation of hair follicle stem cells,” says corresponding author Ya-Chieh Hsu, a professor of stem cell and regenerative biology, in a statement per SWNS.
The study, appearing in the journal Nature, identifies the process that underpins hair loss for the first time and reveals how to reverse it, allowing for a potential groundbreaking baldness cure.
“Chronic, sustained exposure to stressors can profoundly affect tissue homeostasis, although the mechanisms by which these changes occur are largely unknown,” researchers write in their report. “The stress hormone corticosterone—which is derived from the adrenal gland and is the rodent equivalent of cortisol in humans—regulates hair follicle stem cell (HFSC) quiescence and hair growth in mice.”
Turning back the clock on hair’s lifespan
Study authors explain the hormone regulates dormancy and activity of hair follicle stem cells (HFSCs) in mice. In the absence of systemic corticosterone, the little cavities where each hair grows enter substantially more rounds of the regeneration cycle throughout life.
“When corticosterone levels are elevated, hair follicles stay in an extended rest phase and fail to regenerate,” says Hsu. “Conversely, if corticosterone is depleted, hair follicle stem cells become activated and new hair growth occurs.”
An analysis discovered corticosterone suppresses production of GAS6. In the absence of the hormone, it boosts proliferation of hair follicles.
“Restoring the expression of GAS6 could overcome stress-induced inhibition of hair follicle stem cells – and might encourage regeneration of growth,” Hsu notes. “It might therefore be possible to exploit the ability of HFSCs to promote hair-follicle regeneration by modulating the corticosterone–GAS6 axis.”
Throughout a person’s lifespan, hair cycles through three stages, growth (or “anagen”), degeneration (“catagen”), and rest (“telogen”). During anagen, a follicle continuously pushes out a hair shaft. In catagen, growth stops and the lower portion shrinks, but the hair remains in place. During telogen, it remains dormant.
Under severe stress, many hair follicles enter this phase prematurely and the hair quickly falls out, leading to baldness. This lifespan is much shorter in the corticosterone-free mice than controls; less than 20 days compared with two to three months.
‘Exciting findings’ in long-sought journey to baldness cure
Their follicles also engaged in hair growth roughly three times as often. However, researchers restored their normal hair cycle by feeding the subjects corticosterone. Interestingly, when they applied various mild stressors to the controls for nine weeks, corticosterone rose and hair stopped growing. These stressors included tilting their cage, isolation, crowding, damp bedding, rapid lighting changes, and restraining. Injecting GAS6 into their skin reinitiated hair growth with no side-effects.
“These exciting findings establish a foundation for exploring treatments for hair loss caused by chronic stress,” adds Prof. Rui Yi, a dermatalogist at Northwestern University who is not involved in the study.
The study also reveals GAS6 increases expression of genes involved in cell division in HFSCs.
“So, the authors might have uncovered a previously unknown mechanism that stimulates HFSC activation directly by promoting cell division,” Prof Yi continues. “In aging skin, most progenitor cells harbor DNA mutations – including harmful ones that are often found in skin cancers – without forming tumors.
“It will be crucial to see whether forced GAS6 expression could inadvertently unleash the growth potential of these quiescent but potentially mutation-containing HFSCs,” Yi concludes. “Modern life for humans is inevitably stressful. But perhaps, one day, it will prove possible to combat the negative impact of chronic stress on our hair, at least – by adding some GAS6.”
SWNS writer Mark Waghorn contributed to this report.