Some discover their first gray hair at the age of 15, others at 40. We know that there is a part of genetics and time passing, but if these were not the only reasons? Researchers from the National Institutes of Health and the University of Alabama at Birmingham in the United States have found that our immune system plays an important role in the graying of our hair. The results of their research have appeared in the journal PLOS Biology.
In the bulb of our hair are melanocytes, cells produced by melanocyte stem cells. Melanocytes make melanin which gives color to our hair. These are also the same cells that color our skin. When a hair falls, the stem cells will produce new melanocytes for the new bulb, also called follicle. With age, stem cells stop working and our hair grows back without pigmentation, so it becomes gray or white. But what is the link with the immune system?
Too much interferon harms our melanocytes
Our immune system is constantly fighting viruses and bacteria, prompting threatened cells to produce molecules called interferons. These molecules make it possible to indicate to other cells that it is necessary to activate the mechanisms preventing the replication of viruses and bacteria, and also to call the cells “soldier” which protect our body by getting rid of intruders. The researchers discovered that an excess of interferons affected a certain protein, called MITF, necessary for the proper function of melanocytes.
The researchers observed that when a mouse saw its immune system activated, it resulted in a significant loss of melanocytes and melanocyte stem cells, and therefore the appearance of a large number of gray hairs. This reaction could explain why people develop white hair early on, especially if they have been exposed to many infections since childhood. Further studies are needed to understand the underlying mechanisms and whether the same is happening in humans. But the scientists hope their research will help them learn more about diseases that alter depigmentation, such as vitiligowhich affects skin pigments.
Read also :
How to keep your hair white
Castor oil, source of beauty for the hair
