A team led by Dr. Albert Edge of Harvard Medical School and Massachusetts Eye and Ear Infirmary reported the successful restoration of hearing in mice that had noise-induced deafness in the Jan. 9, 2013, issue f the journal Neuron.
Humans like all mammals cannot regenerate the sound sensing hair cells in the inner ear like fish and birds. Loss of these sound sensing hair cells is the primary cause of noise-induced deafness in people.
The investigators found that new hair cells formed after inner ear stem cells were treated with a drug (called a gamma-secretase inhibitor) that blocks the Notch pathway. Inhibition of the Notch pathway has previously been shown to increase hair cell differentiation in the inner ear.
We show that hair cells can be regenerated from the surrounding cells in the cochlea. These cells, called supporting cells, transdifferentiate into hair cells after inhibition of the Notch signaling pathway, and the new hair cell generation results in a recovery of hearing in the region of the cochlea where the new hair cells appear," says Dr. Edge.
The hearing recovery in the test mice was partial but the methodology is the most promising advance to date in restoring noise-induced hearing loss.
The U. S. Census Bureau identifies 4.36 percent of Alabama’s population (199,230 people) as deaf.
The research was reviewed at the Eureka Alert website on the date of publication.