Although it seems counterintuitive, tests indicate that plucked follicles ‘communicate’, causing an immune response that leads to regrowth
Baldness is often dreaded by men and there are few, if any, satisfactory options for reversing it. Now scientists have discovered a potential solution, after showing that plucking hair out could actually stimulate growth.
The counterintuitive discovery, in mice, demonstrates a previously unknown method for triggering hair regeneration. Although the work is at an early stage, the authors believe the same process could be helpful for tackling hair loss in men or people with alopecia.
Philip Murray, of Dundee University and a co-author, said the findings now need to be tested in people. “It would be a bit of a leap of faith to expect this to work in bald men without doing more experiments,” he said.
The study found that when hairs were plucked in a specific configuration, follicles in the skin were prompted to send out a “distress” signal that led to even more hairs growing back. Plucking our 200 hairs triggered the growth of up to 1,200 replacement hairs in the mice, the study found.
Tests showed that the plucked follicles signal distress by releasing inflammatory proteins, which cause immune cells to rush to the site. In turn, these send out signals to all neighbouring follicles indicating that it is time to grow more hair.
“We’ve made a discovery about how hair communicates when it’s distressed,” said Murray.
The study, published in the journal Cell, showed that the pattern in which the hair was plucked played an important role in the strength of the “distress” signalling process. The researchers tested this by plucking 200 hair follicles, one by one, in different configurations on the back of a mouse. When plucking the hairs in a low-density pattern from an area more than six millimetres across, no hairs regenerated. However, higher-density plucking from circular areas with diameters between three and five millimetres triggered the regeneration of between 450 and 1,300 hairs – and the regeneration sometimes spilled out beyond the plucked area.
The authors believe that hair follicles do not simply respond individually to being plucked, but also communicate between themselves - something called “quorum sensing” - and effectively make a group decision about the level of immune response that is necessary. In the case of widely spaced plucking, the follicles are too far apart to be able to signal collectively. However, when the damage is tightly packed a more extreme response is mounted, leading to much stronger hair regrowth.
A potential drawback in balding men might be that their hairs are already too sparsely spaced for the approach to be helpful.
“It is a good example of how basic research can lead to a work with potential translational value,” said Cheng-Ming Chuong, professor of pathology at the University of Southern California and lead author.
Could this discovery be used to tackle baldness and alopecia? Tests are at an early stage, but could provide a solution in the future. Photograph: Asger Carlsen/Getty Images