Researchers have identified the biological mechanism by which chronic stress damages hair follicle stem cells, confirming long-term observations that stress can lead to hair loss.
In a study in the mouse, published in the journal Nature, the researchers found that a major stress hormone puts the hair follicle stem cells into a prolonged resting phase, without regenerating in the follicle or hair.
The researchers identified the specific type of cells and molecule responsible for transmitting the pressure signal to the stem cells and showed that this pathway could be adjusted to restore hair growth.
“The skin offers an accessible and accessible system for studying this important problem in depth, and in this work we found that stress actually inhibits stem cell activation and fundamentally alters the frequency with which hair follicle stem cells regenerate tissue,” said Harvard researcher Ya-chia Hsu.
The hair follicle naturally passes between growth and rest, a process driven by the stem cells of the hair follicle. In the growth phase the stem cells of the hair follicles become reactivated by the follicle and hair, and hairs lengthen daily.
At rest, the stem cells are quiet and hairs shed more easily. Hair loss can occur if the hairs are shed and the stem cells remain silent without regenerating in new tissue.
The researchers examined a mouse model of chronic stress and found that the stem cells of the hair follicles remained at rest for a very long time without regenerating in the tissues.
A major stress hormone produced by the adrenal glands, corticosterone, was adjusted by chronic stress; Providing corticosterone mice that will restore the effect of stress on stem cells
The corresponding hormone in humans is cortisol, often referred to as the “stress hormone”.
Under normal conditions, hair follicle regeneration slows down over time – the resting phase lengthens as the animals age. But when the researchers removed the stress hormones, the resting stage of the stem cells became extremely short and the mice constantly entered the growth phase to renew hair follicles throughout their lives, even when they were old.