Of Mice And Balding Men

By the time they are 50 years old, up to 50 percent of Americans will suffer some sort of hair loss. But now, thanks to pioneering gene therapy and a few mice, there s a little patch of black.

Researchers at the Weill-Cornell Medical College may have unlocked the secret to curing baldness, reports CBS News Correspondent Elizabeth Kaledin.

Dr. Ronald Crystal, director of the Institute of Genetic Medicine, says, "What we're doing with gene therapy is taking an old organ, in this case the scalp, and trying to restore its youth."

To do that, Dr. Crystal and his colleagues rely on a gene known as the sonic hedgehog, which is normally involved in hair follicle growth. Using a virus to transport it, the gene is injected into mice, stimulating new hair growth.

"And so what we're doing," Dr. Crystal says, "is we're taking follicles that were sleeping, if you will, and we're genetically waking them up and we say, 'Start growing.'"

To chart the growth of hair, researchers simply shave the mice, inject the gene into a small patch on their backs and within only two weeks, new hair appears on the injection site.

If the speed in which new hair grows on mice can be duplicated in humans, dermatologists say gene therapy for baldness could have a huge impact.

"I think this is great news for understanding the biology of how and why hair grows when it does," says Dr. Ken Washenik of the N.Y.U. School of Medicine.

Since it usually takes a year for hair to grow back after chemotherapy, the breakthrough in mice could be particularly beneficial to women fighting cancer, or the millions of men in hair-loss denial.

Too much of the gene is known to cause cancer in mice, so researchers admit they have a long way to go before saying gene therapy for baldness can be used in the species in whom being bald matters most.