Promising Research Into Regenerating Inner Ear Hair Cells

Many of the problems that cause hearing problems in our patients cannot be reversed which can be quite frustrating for our hearing professionals. One of the main reasons for hearing loss, for example, is damage to the tiny hair cells in our inner ears that vibrate in reaction to sound waves. These vibrations are interpreted by the brain into what we call hearing.

The sensitivity of these tiny hair cells enables them to vibrate in such a manner, and thus makes it possible for us to hear, but their very sensitivity makes them extremely fragile, and at risk of damage. This damage may occur as the result of aging, certain medications, infections, and by extended exposure to high-volume noises, resulting in noise-induced hearing loss. In humans, once these hair cells are damaged or destroyed, they cannot be regenerated or “fixed.” Since we cannot reverse the damage, hearing professionals and audiologists turn to technology instead. We make up for hearing loss due to inner ear hair cell damage with hearing aids and cochlear implants.

This would not be true if humans were more like fish and chickens. Unlike humans, some fish species and birds have the ability to regenerate their damaged inner ear hair cells and regain their lost hearing. Bizarre, but true. Zebra fish and chickens are just 2 examples of species that have the capacity to automatically replicate and replace their damaged inner ear hair cells, thus allowing them to fully recover from hearing loss.

While it is crucial to point out at the outset that the following research is in its beginning stages and that no practical benefits for humans have yet been achieved, sizeable breakthroughs in the treatment of hearing loss may come in the future as the result of the innovative Hearing Restoration Project (HRP). The not-for-profit organization, Hearing Health Foundation, is currently conducting research at laboratories in Canada and the United States Working to isolate the molecules that allow the replication and regeneration in some animals, HRP researchers hope to find some way to stimulate human inner ear hair cells to do the same.

Because there are so many distinct compounds involved in the regeneration process – some that facilitate replication, some that hinder it – the scientists’ work is slow-moving and challenging. But their hope is that if they can identify the molecules that stimulate this regeneration process to happen in avian and fish cochlea, they can find a way to stimulate it to happen in human cochlea. Some of the HRP researchers are pursuing gene therapies as a way to stimulate such regrowth, while others are working on stem cell-based approaches.

Although this work is still in the early stages, our staff wishes them quick success so that their results can be extended to humans. Absolutely nothing would be more satisfying than to be able to offer our hearing loss patients a true cure.