June 5, 2017
One billion people throughout the world are at risk of experiencing hearing loss at some point in their lives. Scientists have therefore been working to find solutions to this growing problem. Hearing aids and cochlear implants have seen rapid improvements and advances in technology, but they still merely mimic the hearing process, and don’t cure it. Complaints such as tinny or robotic-sounding voices and diminished enjoyment of music are urging another way to restore hearing.
Progressive hearing loss is most often caused by the loss of hair cells in the inner ear that allow us to detect sound. Some bird and fish species are able to re-grow these cells, but humans cannot. It then follows that if humans could regrow these hair cells, hearing could be restored naturally.
Novartis, a Swedish pharmaceutical company, recently sponsored a set of clinical trials to test an inner-ear hair cell regrowth technique on human subjects. When conducting preliminary trials on mice, researchers were successful in restoring partial hearing. The trials are still ongoing, but the eight participants have already begun noticing improvement in their hearing abilities.
Atoh1 is the gene that triggers hair cell growth in the inner ear. Scientists have focused on this gene, which is “turned off” after the cells finish growing, even before birth. Scientists hope to use gene manipulation to “turn back on” these genes and promote this hair cell growth once again. They implant the gene into a cold virus and implant it into the eardrum using a laser and syringe.
Though participants have seen some improvement in hearing, total restoration has proven elusive. Scientists hope that this method may provide enough improvement that patients can then use hearing aids to further improve speech comprehension and other hearing abilities.
Scientists are also working to identify other genes that also play a role in this cell growth progression, and hope that eventually they may develop more advanced techniques for hearing restoration. Whereas this procedure is aimed at hearing loss caused by very loud sounds or drug toxicity, there is more research underway to find treatments for genetic hearing loss as well.
The approach is to introduce a DNA sequence that will help a “broken” gene to work again. Malfunctioning sensory cells are responsible for the hearing loss, and it is hoped that those cells can be made functional again.
This exciting new field of research may soon be able to reverse hearing damage and loss, but until then, prevention is key. Come in for a hearing test today and learn the best ways to protect your hearing health.