Researchers Find a Way to Re-Grow Human Hair

Current hair-loss treatments only focus on slowing down the rate of hair-fall. A new study has found that hair growth can be stimulated, helping men and women fight early-stages of baldness.

Researchers found that the key to stimulating hair growth was to make human papillae grow like rodent hair. The study, conducted by researchers at Columbia University Medical Center (CUMC) and colleagues, showed that it was possible to grow human hair using few strands of donor hair.

"About 90 percent of women with hair loss are not strong candidates for hair transplantation surgery because of insufficient donor hair. This method offers the possibility of inducing large numbers of hair follicles or rejuvenating existing hair follicles, starting with cells grown from just a few hundred donor hairs," said co-study leader Angela M. Christiano, PhD, the Richard and Mildred Rhodebeck Professor of Dermatology and professor of genetics & development.

Human skin is made of many layers- with the outermost being the epidermis. Dermal papillae are tiny protrusions of dermis into the epidermis. These papillae play a vital role in supplying nutrients to the epidermis and even help collect sensory data. Research has shown that these nipple-like extensions are important in the formation of hair follicles.

The hair follicle is the skin organ that produces the hair. At the base of the hair follicle are nerve fibers that surround each hair bulb. Sebaceous glands are also present along the follicles. These glands secrete oils that condition the hair. The hair growth cycle is controlled by interactions between epithelial cells, which surround the hair shaft, and dermal papilla cells that are at the base of the follicle bulb.

The idea of cloning hair follicles using dermal papilla isn't new and has been around for about four decades.

"However, once the dermal papilla cells are put into conventional, two-dimensional tissue culture, they revert to basic skin cells and lose their ability to produce hair follicles. So we were faced with a Catch-22: how to expand a sufficiently large number of cells for hair regeneration while retaining their inductive properties," said Colin Jahoda, PhD, professor of stem cell sciences at Durham University, according to a news release.

Dr. Jahoda had earlier found that rodent hair can be grown in a lab using rodent papillae, mostly because rodent pappilae clump together forming a network. This aggregation helps the papillae share information and stimulate hair-growth in surrounding skin-cells.

For the present study, researchers obtained dermal papillae from seven human donors and grew them in a tissue culture without adding any other growth factors. These cells were then transplanted on to the backs of mice. These mice had human skin grafted on their backs.

Study results showed that five out of seven mice had new hair that lasted for six weeks. Researchers then conducted genetic tests and confirmed that the hair belonged to the hair donors.

Of course, additional research is required before the treatment could be applied to cure balding in humans.

The study is published in the journal Proceedings of the National Academy of Sciences (PNAS).