Researchers found plucking 200 hairs from a 3-5 mm region of a mouse's back led to the growth of 450-1,300 new hairs.
Image credit: Cheng-Ming Chuong
Led by Prof. Cheng-Ming Chuong, of the Keck School of Medicine at the University of Southern California, the study reveals how individually plucking 200 hairs from the back of a mouse in a specific pattern led to the regeneration of up to 1,300 hairs.
Prof. Chuong and his team publish their findings in the journal Cell.
Male pattern baldness accounts for around 95% of hair loss in men, according to the American Hair Loss Association. By the age of 35, around two thirds of men in the US will have experienced some level of hair loss.
Common causes of hair loss in women - who account for 40% of all hair loss sufferers - include female pattern baldness and traction alopecia, which is hair loss caused by trauma to the hair follicles - skin organs that grow hair.
According to Prof. Chuong and colleagues, it is well established that damage to hair follicles can influence hair regeneration in the surrounding areas. As such, they hypothesized that hair follicle stimulation through hair plucking may lead to new hair growth, and they set out to test this theory.
One by one, the team plucked 200 hairs from the back of a mouse in a number of different patterns.
They found that plucking the hairs from an area more than 6 mm in diameter failed to regenerate new hairs. Plucking hairs from a region 3-5 mm in diameter, however, led to the regeneration of 450-1,300 new hairs, and these new hairs even grew outside of the plucked area.
Commenting on their findings, Prof. Chuong says:
"It is a good example of how basic research can lead to work with potential translational value. The work leads to potential new targets for treating alopecia, a form of hair loss."
Hair plucking triggers 'distress signals' to encourage new hair growth
Through conducting molecular studies, the researchers found that plucking hairs from the back of the mouse generated new hair growth through a process called "quorum sensing."
Put simply, the damage to the hair follicles caused by hair plucking triggered the release of inflammatory proteins. These proteins send a "distress signal" to immune cells, calling them to the injury site.
Next, the team explains, the immune cells express signaling molecules - such as tumor necrosis factor alpha (TNF-α). At certain concentrations, these signaling molecules encourage both damaged and undamaged hair follicles to grow new hair.
Prof. Chuong says these findings may have wider implications; it is possible that minor damage to other organs could stimulate some form of regeneration. "The implication of the work is that parallel processes may also exist in the physiological or pathogenic processes of other organs," he adds, "although they are not as easily observed as hair regeneration."
Talking to BBC News, Prof. Chris Mason, a professor of regenerative medicine at University College London in the UK, said the idea of quorum sensing for hair regeneration is "smart," but it is unclear as to whether it could be an effective treatment for human hair loss.
"That's the million-dollar question. I'm not sure. As it stands here, you've got to have some hair to pluck." he said. "Could you tap into the pathway with a cream or injection? That could well be possible - or maybe don't wait until you're totally bald?"
In January, Medical News Today reported on a study by researchers from the Sanford-Burnham Medical Research Institute in La Jolla, CA, revealing a potential way to generate new hair using human pluripotent stem cells.