Protein identified that triggers male hair loss.

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From BBC news -

A biological clue to male baldness has been discovered, raising the prospect of a treatment to stop or even reverse thinning hair.

In studies of bald men and laboratory mice, US scientists pinpointed a protein that triggers hair loss.

Drugs that target the pathway are already in development, they report in the journal Science Translational Medicine.

The research could lead to a cream to treat baldness.

Most men start to go bald in middle age, with about 80% of men having some hair loss by the age of 70.

The male sex hormone testosterone plays a key role, as do genetic factors. They cause the hair follicles to shrink, eventually becoming so small that they are invisible, leading to the appearance of baldness.
Now, researchers at the University of Pennsylvania have analysed which genes are switched on when men start to go bald.

They found levels of a key protein called prostaglandin D synthase are elevated in the cells of hair follicles located in bald patches on the scalp, but not in hairy areas.

Mice bred to have high levels of the protein went completely bald, while transplanted human hairs stopped growing when given the protein.

Prof George Cotsarelis, of the department of dermatology, who led the research, said: "Essentially we showed that prostaglandin protein was elevated in the bald scalp of men and that it inhibited hair growth. So we identified a target for treating male-pattern baldness.

"The next step would be to screen for compounds that affect this receptor and to also find out whether blocking that receptor would reverse balding or just prevent balding - a question that would take a while to figure out."

The inhibition of hair growth is triggered when the protein binds to a receptor on the cells of hair follicles, said Prof Cotsarelis.

Several known drugs that target this pathway have already been identified, he added, including some that are in clinical trials.

The researchers say there is potential for developing a treatment that can be applied to the scalp to prevent baldness and possibly help hair regrow.

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Further information from NY Times -


FEW things are as likely to strike fear in the hearts of men as the sight of a receding hairline in the bathroom mirror. Farewell, sweet youth; hello, male pattern baldness.
Dr. George Cotsarelis, a dermatologist at the University of Pennsylvania, and colleagues have identified a molecule that inhibits hair growth in the follicle.
Valerie Horsley, a professor at Yale, is investigating how fat cells in the skin of mice send signals to hair follicles.
Hair follicles are the culprits in this unfortunate turn of events. These tiny holes on the scalp shrink over time, depending on genetics and the presence of testosterone, producing not the lush locks of youth but rather hair that gradually thins into peach fuzz.

Now a doctor who has spent several decades learning the treacherous ways of the follicle may have discovered a new way to put the brakes on the process.

Dr. George Cotsarelis, a professor and head of dermatology at the Perelman School of Medicine of the University of Pennsylvania, and colleagues have identified a molecule that inhibits hair growth in the follicle. The research team also pinpointed the receptor on the cell where the deed is done, making it a target for possible future therapies for male pattern baldness.

Treatments focusing on this specific receptor are already in the pipeline, developed by pharmaceutical companies to treat illnesses related to allergies, said Dr. Luis Garza, lead author of the paper announcing the discovery, which appeared in Science Translational Medicine.

“The receptor is already a target for other diseases,” he said. “The exciting aspect is that we can try to use those drugs now being developed to treat male pattern baldness.” About 10 drugs that take aim at the receptor are going through clinical trials to treat allergic diseases, he said.

Dr. Garza, who joined Dr. Cotsarelis’s lab six years ago and worked with him on problems of male pattern baldness, is now an assistant professor in the dermatology department at the Johns Hopkins University School of Medicine.

Desmond J. Tobin, a professor of cell biology and director of the Center for Skin Sciences at the University of Bradford in England, said he welcomed the discovery.

“We are definitely in need of a new way to tackle this problem,” Dr.Tobin said.

Male pattern baldness is the most common form of hair loss in men. Current treatments include hair transplants and two medications approved by the Food and Drug Administration — one a lotion containing minoxidil, the second a pill containing finasteride.

The discovery isn’t likely to help men who are already bald. “It would be too much to turn the clock back and reverse very extensive hair loss,” Dr. Tobin said.

But should a treatment based on the discovery come to pass, it could be significant for men who are in the early stages of balding. “You could probably slow the hairs from getting so fine and thin in the first place,” he said. “That would be a breakthrough.”

The miniaturized hairs of balding men remain on the scalp for a few days to a few weeks, Dr. Tobin said. In contrast, normal scalp hairs typically remain for at least three years. “If you could release the hairs to grow more normally in the scalp, you’d let the hair follicles go on for a bit longer,” he said. “They would produce visible, cosmetically attractive hair.”

Dr. Cheng Ming Chuong, a professor of pathology at the Keck School of Medicine at the University of Southern California, also was enthusiastic about the discovery. “We in the field are excited to see new progress,” he said. “Once you know the molecules that do the work, scientists can design different compounds to deal with the problem.”

Dr. Cotsarelis, who describes himself as “enamored with the hair follicle,” has been hard at work on balding scalps since he identified hair follicle stem cells in mice in 1990, when he was a postdoctoral fellow. “We were able to show that when we isolated the cells and injected them into another mouse,” he said, “the mouse made new hair follicles.”

In the most recent work, he and his team studied the balding and nonbalding areas of men’s scalps. They did detailed genetic analysis of the cells, pinpointing the molecule, Prostaglandin D2, that was found at higher levels in the bald scalps of men. Dr. Cotsarelis and Dr. Garza are co-inventors on a patent owned by the University of Pennsylvania describing the pathway by which the prostaglandin is inhibited at the receptor.

ALSO at work on the problem of male pattern baldness is Valerie Horsley, an assistant professor of molecular, cellular and developmental biology at Yale. She is investigating how fat cells in the skin of mice send signals to hair follicles.

“Our work shows that fat cells can induce hair growth in mice,” she said. She is now at work on the molecular mechanism by which these cells act.

Dr. Cotsarelis, meanwhile, is working on another vexing problem. “Now we need to look at women who are losing their hair,” he said.