If you're like me, you sometimes worry about your hearing. Certain tones of voices and noisy places can make it difficult to pick up every word in a crowded room. Although I don't have a severe problem (yet), many people do. Now Stanford researcher and otolaryngologist Alan Cheng, MD, and his colleagues have published work (subscription required) that one day may help those with what's been called "the invisible disability." From my release:
Twenty percent of all Americans, and up to 33 percent of those ages 65-74, suffer from hearing loss. Hearing aids and, in severe cases, cochlear implants can be helpful for many people, but neither address the underlying cause: the loss of hair cells in the inner ear. Cheng and his colleagues identified a class of cells called tympanic border cells that can give rise to hair cells and the cells that support them during a phase of cochlear maturation right after birth.
Hair cells work by swaying in response to the vibrations in the air caused by sound - like seaweed in an ocean current. But when these cells are damaged, that's that:
"It’s well known that, in mammals, these specialized sensory cells don’t regenerate after damage," said Alan Cheng, MD, assistant professor of otolaryngology. (In contrast, birds and fish are much better equipped: They can regain their sensory cells after trauma caused by noise or certain drugs.) “Identifying the progenitor cells, and the cues that trigger them to become sensory cells, will allow us to better understand not just how the inner ear develops, but also how to devise new ways to treat hearing loss and deafness."
Cheng, who is a member of the Stanford Initiative to Cure Hearing Loss, collaborated with Stanford developmental biologist Roel Nusse, PhD, to investigate which cells in the inner ear might be responsive to a developmental pathway called Wnt that drives the renewal and proliferation of many types of stem, or progenitor cells. Together they identified a Wnt-responsive population of cells in the inner ear called the tympanic border cells and showed that, when grown under proper conditions in the laboratory, they could become sensory and supporting cells.
Now the next step is learning whether and how these cells could be coaxed to jump into action in people with hearing loss, says Cheng.
Previously: Regenerating sensory hair cells to restore hearing to noise-damaged ears, Stanford researcher comments on the use of human embryonic stem cells to restore hearing, and Growing new inner-ear cells: a step toward a cure for deafness