It is common advice for listeners to make sure that their music is not blasting too loudly on their headphones, or for concert attendees not to stand too closely to speakers. In the long-term, listening to loud sounds for a prolonged period may cause hearing loss, and it commonly strikes musicians and DJs. However, an exciting new study suggests that we may soon be able to roll back hearing loss, meaning that individuals will be able to hear better in the future. The finding is significant because hearing loss is estimated to affect nearly 50 million people - a sixth of Americans - in the United States alone.
The study targets sensorineural hearing loss, which is most commonly caused by the erosion of sensory hair cells in the cochlea, the portion of the inner ear chiefly responsible for hearing. Researchers applied a drug, chosen because other studies had found that it could grow hair cells when scientists made stem cells isolated from the inner ear, to the cochlea of deaf mice. The drug prevented the signaling produced by a protein called Notch, which appears on the surface of cells that surround hair cells. Those surrounding cells became hair cells after the administration of the drug.
Researchers found that the mice's hearing drastically improved, and they were able to trace that ability to their new hair cells. "We're excited about these results because they are a step forward in the biology of regeneration and prove that mammalian hair cells have the capacity to regenerate," Dr. Albert Edge said in a statement. "With more research, we think that regeneration of hair cells opens the door to potential therapeutic applications in deafness."
The study was published in the journal Neuron and was conducted by researchers at Harvard Medical School, Keio University School of Medicine in Japan and the Massachusetts Ear and Eye Infirmary.