New research suggests that stress would affect the nervous system and stem cells in the follicles, leading to the appearance of gray hair.
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Who else, who least we are all exposed to stress, physiological reaction that affects the inside of our body, but that can also be visible outside. Cases in which a person, in a short period of time, loses the color of their hair and begins to show gray hair due to stress are known. A group of scientists was dissatisfied with the available explanations of this phenomenon and offered a new one, which relates it to the depletion of mother cells.
Researchers from the Department of stem cells and regenerative biology at Harvard University (Massachusetts, USA) and several collaborators carried out a series of experiments with dark-haired mice. They induced skin stress to a point where rodents began to graze in parts, as a study posted this week
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First of all, the authors emphasize that the regeneration of the coat is due to two different populations of stem cells: some correspond to the hair follicle and are epithelial tissues, while others are future melanocytes, or pigmentation cells, and have their origin in a tissue embryonic. This last category is not renewed because the tissue itself disappears before the baby sees light and is responsible for the color; at the same time that the first fosters growth and both work independently.
Under stress conditions, scientists estimate, the nerves of the sympathetic system are activated, something that suddenly releases a large number of neurotransmitters (norepinephrine, also known as norepinephrine). This makes a variety of resting stem cells proliferate rapidly, differentiate, migrate from the stressed area and finally run out. In this way, stress leads to the loss of melanocyte stem cells.
The mice were repeatedly injected under their skin with a toxin that does not poison but produces a lot of itching. Princeton scholars called stress the itching felt by animals and considered proven that this was the cause of the subsequent loss of pigmentation of the coat, which was permanent in all cases.
Professor Ya-Chieh Hsu, lead author of the study, said that his work lays “the basis for understanding how stress affects other tissues and organs of the body.” Hair pigmentation is a proprietary system to begin this knowledge by being “accessible and manageable” and the researchers were “really interested in seeing if stress effectively dyed the hair gray.”
The theories prior to these experiments related gray hair to stress but through immune attacks or stress hormones, such as cortisol.
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