Gene therapy holds out hope for baldness cure
Ian Sample, science correspondent
Thursday May 17 2007
Skin cells have been primed to regrow hair follicles for the first time, leading scientists to claim a breakthrough in the quest for a cure for baldness.
Researchers hope that a treatment for hair loss may be within sight after healthy hair-producing follicles were regenerated in adult skin in mice.
The team made the breakthrough by awakening a sequence of dormant genes, which triggered a flood of stem cells into patches of hairless skin. To the researchers' surprise, the stem cells were able to form hair follicles.
The findings overturned scientists' belief that mammals are born with a set number of hair follicles and are unable to grow new ones.
While newts and salamanders are known to be capable of regenerating entire limbs, researchers believed mammals had a much more restricted ability to regrow body tissues. The researchers discovered the effect during experiments into the healing mechanisms of the animals. When thin sheets of skin were taken from the rodents, the researchers found that not only did the skin heal, but it reformed with new hair follicles.
Tests revealed that a set of genes, which are switched off shortly after the embryo stage of development, had been re-awakened, causing stem cells to rush to the site of the wound and generate new follicles.
Further studies showed that injecting a protein called Wnt onto the patch of skin doubled the number of hair follicles that formed. By blockling Wnt proteins in the animals, the researchers were able to stop the growth of new hair follicles.
George Cotsarelis, a dermatologist at the University of Pennsylvania who led the study said: "We've found that we can influence wound healing with Wnts or other proteins that allow the skin to heal in a way that has less scarring and includes all the normal structures of skin, such as hair follicles and oil glands, rather than just a scar." The research is reported in the journal Nature.
The scientists claim the findings have broader implications than a cure for male-pattern baldness, suggesting it raises the possibility of treatments for other follicle-related disorders, such as acne, scalp conditions and excessive hair growth. The researchers are now licensing the technology through a American company called Follica Inc.
"Up to now we thought that the number of hair follicles we have is set before we were born and can only go downhill from there," said Denis Headon, a developmental biologist at Manchester University. "This work shows that new hair follicles are made in adult skin, at least when it is healing a wound. The researchers also found a way to artificially soup up this natural process, causing mice to grow twice as many new hairs by giving the skin a specific molecular signal. The implication is that it might be simpler than we thought to make new hair follicles as a treatment for hair loss."
Desmond Tobin, director of the medical biosciences research group at the University of Bradford, said: "It was long thought that hair follicle development, under physiological conditions, was limited to early developmental process.
"Now Cotsarelis' team have convincingly shown that under the conditions peculiar to the wound-healing environment, the highly complex hair follicle can be created anew from apparently unremarkable cells of the healing epidermis and its underlying dermis."
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