But experts have discovered a new way to stimulate hair regrowth using human skin to bring hope to millions of men who are a bald.
Male pattern baldness affects over half of men to some extent over the age of 50 and most men at some stage in their lives. It is a normal part of the ageing process and overall most men choose not to undergo any kind of treatment.
However, for some men the process of losing their hair can be distressing – particularly if it is excessive or occurs early in life.
But that could soon come to an end, as scientists now believe that they could cure the condition altogether.
We have discovered that macrophages, cells whose main function is traditionally attributed to fight infections and wound repair, are also involved in the activation of hair follicle stem cells in non-inflamed skin.
Dr Mirna Perez-Moreno
Previous research has identified signals from the skin that help prompt new phases of hair growth. Yet the experts have long been puzzled by exactly how different types of cells in the skin actually activate hair growth.
Now, however, researchers at the Spanish National Cancer Research Centre (CNIO) have discovered an unexpected link between skin regeneration and the body’s defence system.
Their efforts have revealed that cells from the immune system called macrophages which devour invading pathogens are somehow involved in the process.
The study, Published in the journal PLOS Biology, suggests that macrophages induce hair growth by surrounding and activating stem cells in the skin which have regenerative capacity.
Dr Mirna Perez-Moreno, who was one of the researchers on the project, said: “We have discovered that macrophages, cells whose main function is traditionally attributed to fight infections and wound repair, are also involved in the activation of hair follicle stem cells in non-inflamed skin.”
Dr Perez-Moreno and her colleagues believe that their discovery could potentially be applied to issues involving tissue regeneration, ageing and cancer.
Hair is made in hair follicles which are like tiny pouches just under the skin surface. A hair normally grows from each follicle for about three years. It is then shed and a new hair grows from the follicle. This cycle of hair growth, shedding and new growth goes on throughout life.
Studies into baldness suggest that it occurs when affected hair follicles on the scalp gradually become smaller than normal. Male hormone are thought to be involved in these changes, though some women – mainly after menopause – can also lose their hair.
The doctor made her discovery unexpectedly, while working on another research project.
Mice that she was working with at the time started to regrow hair after being given anti-inflammatory drugs. She and her lab colleagues then began to test different types of cells involved in the body’s defence system to try and uncover a role in hair growth.
They found that when skin cells are dormant, a fraction of macrophages die naturally due to a normal process called apoptosis. However, the dying and surviving cells activated nearby stem cells and hair began to grow again.
Although the study was carried out on mice, the researchers believe their discovery may enable the development of new treatments for baldness in humans.