For centuries the legend of the hair of people who turn white from fear has persisted.
Notoriously, Marie Antoinette’s lush strawberry blonde locks were said to have turned white the night before her execution.
Now new research, published in the journal Nature, suggests that extreme stress can actually cause hair pigmentation loss.
Experiments conducted by a team from Harvard University have shown that extreme stress levels cause the sympathetic nervous system to become hyperactive, which is responsible for the body’s rapid involuntary response to dangerous or stressful situations.
This, in turn, drives the rapid reduction of the stem cells responsible for hair color, leading to the loss of pigment and the development of white hair.
Dr Ya-Chieh Hsu, lead author of the study, said: “By understanding exactly how stress affects stem cells that regenerate the pigment, we laid the foundation for understanding how stress affects other tissues and organs in the body.
“Understanding how our tissues change under stress is the key first step towards any treatment that can stop or restore the harmful impact of stress. We still have a lot to learn in this area.”
Hair color is determined by cells called melanocytes, which are derived from melanocyte stem cells (MeSC).
As we age, the MeSC supply is gradually exhausted, causing the replacement of pigmented hair with white hair.
In collaboration with scientists from around the world, the Harvard team exposed mice to various types of stressors, including pain, moderation and psychological stress, during the different stages of hair growth.
Each stressor has been found to cause MeSC exhaustion, eventually leading to the development of patches of white hair.
On further investigations, the authors found that stress activated the sympathetic nervous system, triggering the release of a neurotransmitter called norepinephrine.
They found that norepinephrine caused the MeSC to “move away” from the hair follicles eventually, leading to color loss.
The team then looked for genes whose expression was most altered during stress experiments and reduced it to one that encodes a protein called CDK.
When mice were injected with a drug that breaks the coding of the CDK, the researchers found that it prevented the fur from losing color.
Dr Thiago Mattar Cunha, a researcher affiliated with the Inflammatory Disease Research Center in São Paulo, Brazil, and one of the authors of the study, said: “This finding shows that CDK is participating in the process and could therefore be a therapeutic target.
“It is too early to know if one day it will become a goal in clinical practice, but it is worth exploring further.”
The researchers say their results do not provide a cure or treatment for gray hair, but they give an idea of how stress could affect many other parts of the body.