Replacing Lost Hair Cells May Restore Hearing
Gene Therapy to Regrow Hair Cells May Treat Hearing Loss
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
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
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
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.