As many aging rock stars have learned, hearing loss due to inner ear damage is irreversible. Loud music assaults the cochlea, the snail-shaped organ of the inner ear whose tiny hair cells detect sound vibrations. The cochlea translates these into electrical impulses that nerves carry to the brain. Once destroyed, hair cells don't regenerate.
Researchers at Genentech in South San Francisco now report that they've grown new hair cells in tissue taken from newborn rats' cochleas. The scientists used fresh supplies of a gene, Math1, to promote hair cell growth. Although the researchers studied only cells in laboratory dishes, their findings raise hopes that deafness from inner ear damage might be reversible.
"It's an exciting study," says Thomas R. Van De Water, an otolaryngologist at Albert Einstein College of Medicine in New York. The work is the first to initiate hair cell growth by adding Math1, he says.