A new study in mice finds possible explanations for hair loss under stress
Stress is a reaction that all of us have experienced one or more times. Some of our physical reactions related to stress are nerves in a few people, tachycardia or hair loss.
However, until now, it is not fully understood that the direct effect of stress is the cause of hair loss. A new mouse study from Harvard University provides a clue: Stress hormones can slow hair growth.Their Details have been published in the journal Nature.
How hair grows
Maybe you remember a common image in a biology book that shows the skin layer with hair follicles. Specifically, the hair follicle is “hairy” and is the part of the skin that grows by condensing stem cells.
In the human body, there are approximately five million hair follicles.Most of these follicles are concentrated in our head A study by Humboldt University in Germany. On the contrary, according to research, the largest follicle was found in our calf area.
The hair follicle undergoes the growth phase, in which the hair follicle produces new hair, and the rest phase undergoes hair follicle inactivation.
According to researchers at Harvard University, in mice, the increased levels of the stress hormone corticosterone, which is similar to the human hormone cortisol, can make hair follicles stay longer in the resting phase than usual.
Specifically, corticosterone in mice binds to glucocorticoid receptors on cells at the bottom of each hair follicle. This receptor is responsible for the release of chemicals to regulate the hair cycle.
Corticosterone linked to the receptor prevents the production of a protein called GAS6. Without this protein, the stem cells of the hair follicle will not be activated, so that the hair starts to grow.
How stress affects mouse hair
In the Harvard University study, researchers removed the adrenal glands from a group of mice to weaken the production of all stress hormones. The adrenal glands are located above the kidneys and mainly regulate the response to stress through the synthesis of corticosteroids.
In mice without adrenal glands, hair follicles enter the growth phase three times more frequently than in mice under stress. In addition, in normal mice, the quiescent period of follicles is usually in the range of 60 to 100, shortened to 20 days.
After verifying these results, the researchers injected corticosterone into modified mice. In this way, their hair growth cycle is restored to be consistent with the growth cycle of mice with adrenal glands. This shows that stress hormones inhibit hair growth.
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They also found that the cells of the dermal papilla The outermost layer of the dermis, its blood vessels can nourish the hair follicles, When exposed to corticosterone, they stop producing GAS6 protein. This causes the hair to stop growing. By injecting this protein directly into the skin of mice under a lot of stress, the researchers found that the hair began to grow.
According to the researchers, GAS6 or a very similar protein may have the same effect on humans. Among them, you can find ways to relieve hair loss caused by stress.