Cuts and scrapes may be slower to heal in redheads

Red-haired wounds heal more slowly than their blonde, brunette, or black-haired counterparts. A study in mice shows that a genetic variant that causes hair color appears to slow the rate at which damage heals—a finding that could help us better treat wounds in people with hair of all shades.

Our hair color is largely determined by a gene called MC1Rwhich encodes a protein that controls the ratio of black-brown to red-yellow pigment in hair follicles.

People with brown or black hair wear MC1R variants that encode active forms of this protein. But almost all red-haired people have less active or completely inactive forms due to mutations in MC1R. genetics With hair color, the situation is more complicated for blondes, who may also have active or inactive forms of the protein.

The same protein is found in our skin. where it has an anti-inflammatory effect. This led Jenna Cash at the University of Edinburgh, UK, to ask whether it affects wound healing. This process requires a short-term inflammatory response to remove germs and dead cells from the lesion, but if it is excessive or prolonged, healing is impaired.

To study this, she and her colleagues surgically created 4-millimeter-wide wounds on the backs of mice with black and red fur, the latter of which was completely inactive. MC1R protein.

A week later, the red-haired mice's wounds had shrunk by an average of 73 percent, compared with 93 percent in the black-haired group.

This led the team to wonder whether an experimental topical drug that boosts the activity of active forms of the protein but does not affect the completely inactive versions could improve the healing of chronic wounds. They often occur among people with diabeteswhere excess inflammation due to persistently high blood sugar levels can slow wound healing.

To test this, the researchers gave black-haired mice wounds, applied the drug and applied bandages. Other black-haired mice had the same wounds, but were treated with saline and bandages.

A week later, they found that the wounds in the treated mice had shrunk by an average of 63 percent, more than double the wounds in control animals. “If you have a wound that's half the size, I think patients will be thrilled with it, especially after such a short time,” Cash says. Further tests showed that the drug works by reducing the number of inflammatory immune cells.

Because wound healing is so similar in mice and humans, this approach holds promise for treating people, even redheads, most of whom have MC1R proteins with some activity, Cash says. However, people with completely inactive forms will not benefit, she says.

Drugs targeting this protein are already used to treat conditions such as erythropoietic protoporphyria, in which the skin is overly sensitive to sunlight, so the team suspects this approach would have an acceptable safety profile, Cash says. But further research is needed to confirm this, says Kat Bogey at Case Western Reserve University in Ohio. Cash says the team plans to begin human trials soon.

Future work should also test whether the drug works safely and effectively on infected wounds, Bogie said. “There is a possibility that the drug could interfere with the response to infection or have the opposite effect,” she says.

This may seem like bad news to some redheads, as previous studies have shown that they too feel more pain. But Cash stresses that they shouldn't worry. “People with red hair shouldn't worry. We don't have data on people yet, and if a red-haired person sees slightly slower wound healing, they might not even notice – it's probably a pretty small effect.”