14 DAY TRIAL // Some salamanders can regenerate limbs and some lizards can regenerate Tails, not mentioning that reptiles constantly regenerate their teeth while in mammals this phenomenon is far more limited.
But a new research reveals that mammals have significantly higher regenerative abilities than previously thought, as researchers detected hair regrowth in mice with deep skin wounds. These investigations could lead to a treatment to male human baldness and other types of hair loss, by determining epidermal cells to turn into hair follicles. The hair regeneration discovered in mice was linked to molecular processes resembling the embryonic development.
"The findings dispel the dogma that hair loss is permanent in people and other mammals, and that once they are lost new hair follicles cannot grow." said lead researcher Dr. George Cotsarelis, a dermatology professor at the University of Pennsylvania School of Medicine in Philadelphia.
The new follicles worked just like normal ones, passing through the same stages of hair growth, but it lacked pigmentation, being white and marking this way the wound.
"The white-hair issue may not materialize in any baldness remedy in people because the human pigmentation system differs from that in mice." said Cotsarelis.
The scientists induced relatively large wounds on the backs of adult mice and noticed that when the wound was of a certain size new hairs emerged at its center. The skin turned on embryonic phases of hair-follicle development, sending stem cells to the damaged area. The stem cells have the ability to turn in any cell type and in this case, they regenerate follicles, even if they were not the type linked to hair-follicle development.
"They're actually coming from epidermal cells that don't normally make hair follicles. So they're somehow reprogrammed and told to make a follicle," Cotsarelis said.
The team discovered a method of doubling the natural regeneration process, by using a specific molecular signal, but more than five years could pass before a novel anti-baldness treatment will be ready. The method could also be used against skin scars to give them a hairy, normal skin look.
"Repair and regeneration appear to be in competition. Since fast-closing wounds help the survival of wild animals, repair often dominates regeneration. In the practice of medicine, physicians are trained to close wounds as soon as possible, thus leaving not enough time for regeneration to occur." said Dr. Cheng-Ming Chuong, a professor of pathology at the University of Southern California, not involved in this research.