Latest news in Dermatology on November 28th 2018 (5 out of 5)

By stirring the crosstalk among the skin cells that form the roots of the hair, the researchers found that the locks of their hair were pushed back onto damaged skin. The results explain why hair does not grow normally on injured skin and can help find better medications to restore hair growth, say the study's authors.

Led by researchers at the NYU School of Medicine and published in November in the journal Nature CommunicationsThe study examined the effect of distinct signaling pathways on the damaged skin of laboratory mice. The experiments focused on cells called fibroblasts that secrete collagen, the structural protein most responsible for maintaining the shape and strength of skin and hair.

As part of their investigation, the researchers activated the sonic Hedgehog signaling pathway used by the cells to communicate with each other. This pathway is known to be very active during the early stages of human growth in the uterus when hair follicles form, but is also blocked in injured skin in healthy adults. Researchers say this may explain why hair follicles do not grow in the replaced skin after an injury or surgery.

"Our results show that stimulating fibroblasts by the sonic hedgehog can trigger hair growth never seen in wound healing," says lead investigator and cell biologist Mayumi Ito, PhD, associate professor in the department of Ronald O. Perelman dermatology Langone Health.

Regrowing hair on damaged skin is an unmet need in medicine, says Ito, because of the disfigurement suffered by thousands of people affected by trauma, burns and other injuries. However, her most immediate goal, she adds, is to ensure that mature skin returns to its embryonic state to grow new hair follicles, not only on injured skin, but also on those who have fallen bald. because of aging.

According to Ito, scientists have hitherto assumed that, as part of the healing process, collagen accumulation in damaged skin was at the root of its inability to regrow hair. "We now know that it is a signaling problem in very active cells as we develop in the uterus, but less in mature skin cells with age," she adds.

Among the main findings of the study, it was found that no signs of hair growth were observed on untreated skin, but on treated skin, which proves that sonic signaling by a hedgehog was at the origin of hair growth.

To avoid the risk of tumors reported in other experiments that used the sonic hedgehog pathway, the NYU Langone team activated only fibroblasts located just below the surface of the skin, where the first roots of the skin appear. hair follicle (dermal papillae). Researchers have also targeted fibroblasts because cells are known to help direct some of the biological processes involved in healing.

Hair regrowth was observed within four weeks of the skin wound in all treated mice, with the root and stem structures beginning to appear after nine weeks.

Ito says his team is considering new research on how chemical and genetic stimulants of fibroblasts could activate the sonic hedgehog pathway in injured human skin. Its goal is to identify the likely drug targets for hair regrowth.