Scientists Develop Drug That May Be Capable Of Reversing Deafness
A new drug may be capable of restoring hearing for those who are totally deaf. By regenerating the sensory hair cells and stimulating the inner ear, the drug may be able to restore hearing loss caused by noise exposure, infection and toxic drugs—much of which was once thought irreversible.
With the drug, codenamed LY411575 scientists have already succeeded in partially restoring hearing in mice deafened by loud noise. They believe similar restoration of human hearing lost to noise exposure is also possible.
The cochlea contains tiny sensory hairs that enable hearing. When sound vibrations shake the hairs, nerve messages are sent to the brain. Mammals are not capable of reproducing the sound-sensing hair cells. A protein called Notch inhibits new hair growth in the cochlea. If the hairs are gone, hearing is not possible.
The new drug inhibits Notch and has allowed regeneration of sensory hair cells in laboratory mice with noise-induced hearing loss. The study was recently reported in the journal Neuron.
“We show that hair cells can be regenerated from the surrounding cells in the cochlea,” said lead researcher Dr. Albert Edge, from Harvard Medical School. “These cells, called supporting cells, transdifferentiate into hair cells after inhibition of the Notch signalling 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.
“The significance of this study is that hearing loss is a huge problem affecting 250 million worldwide.”