Feb. 15, 2005 - A new study shows that regrowing lost hair cells in the inner ear with gene therapy may one day help restore lost hearing and treat deafness.
The hair cells inside the inner ear respond to sound waves and convert them into signals that the brain processes as sound. Researchers say when these cells are lost or damaged by aging, infection, or disease they cannot be replaced and lead to permanent hearing loss.
But in this study, researchers found that by transferring a gene that stimulates new hair growth into other cells of the inner ear, deafened guinea pigs were able to regain some of their lost hearing. They say it's the first time this type of hair regrowth and improved hearing has been shown in a mature deaf animal.
The gene, called Atoh1, appeared to stimulate new hair growth in the cochlea, a part of the inner ear. By causing surrounding cells to change into hair cells, this gene helps regrow hair and improves hearing.
Researchers say the findings suggest that gene therapy may offer a new approach to treating hearing loss in humans by repairing damaged sensory tissue in the inner ear.
They say a better understanding of the cells that support hearing in the inner ear may also lead to improvements in treatments for hearing loss, such as cochlear implantation, because the presence of some hair cells improves implant function.
For the study, which appears in the journal Nature Medicine, researchers used a virus to deliver Atoh1 to the inner ear cells of deaf guinea pigs. Eight weeks later, they saw new hair cells growing, and brain tests showed that the animals were picking up more sounds, although their hearing was still likely distorted.