Experimental drug may be future treatment for sensorineural hearing loss
You might say researchers had a “gut instinct” when they decided to explore whether a specific drug cocktail could be used to treat hearing loss. The researchers at MIT, Brigham and Women’s Hospital and Massachusetts Eye and Ear were already involved in a study of intestinal cell regeneration when they discovered a similarity between structural support cells in the cochlea and intestinal stem cells.
If regeneration could work in the cochlea like it did in the intestine, they theorized, it could lead to a treatment for sensorineural hearing loss. To test their theory, the researchers exposed cochlea cells from a mouse to a similar drug cocktail to see if they could stimulate them into becoming sound-translating hair cells of the inner ear, and the process worked.
“Hearing loss is a real problem as people get older. It’s very much of an unmet need, and this is an entirely new approach,” says Robert Langer, the David H. Koch Institute Professor at MIT, a member of the Koch Institute for Integrative Cancer Research, and one of the senior authors of the study. His comments appeared in the February 21, 2017 online issue of MIT News.
Other senior authors include Jeffrey Karp, an associate professor of medicine at Brigham and Women’s Hospital (BWH) and Harvard Medical School in Boston, and Albert Edge, a professor of otolaryngology at Harvard Medical School based at Massachusetts Eye and Ear. The paper was published in the February 21 issue of Cell Reports.
An important—but early—step
The discovery is an important step toward reversing sensorineural hearing loss, one of the most common forms of hearing loss among the 48 million Americans who report some degree of hearing impairment.
Specifically, sensorineural hearing loss is caused by damage to hair cells of the inner ear and/or the auditory nerve that connects the ear to the brain. Damage can be caused by the aging process and from either a one-time or prolonged exposure to excessive noise.
These hair cells play an important role in human hearing by translating sound the ear collects into electrical impulses for the brain to interpret as recognizable sound. Unlike some animals such as fish, reptiles and amphibians, human hair cells do not regenerate, causing permanent hearing loss when they are damaged.
Currently, sensorineural hearing loss is treated with hearing aids or cochlear implants, which work with an individual’s remaining sense of hearing to amplify sounds. Although today’s digital hearing devices are more effective than they were ten years ago, they do not restore the sense of hearing to its normal state.
Still experimental and far from being approved
The study’s researchers envision these drugs will eventually be injected into the middle ear, much like injections currently used to treat ear infections, but the treatment is far from being available at your local hearing center. New drug therapies must undergo extensive efficacy and safety testing and approval from the Food and Drug Administration (FDA) which can take many years. However, some of the researchers involved in the study have formed a company, and they hope to begin testing the new therapy on human patients within the next 18 months. If you have hearing loss now, hearing aids and other assistive listening devices are still the best treatment for sensorineural hearing loss for the foreseeable future.
If you aren’t hearing like you used to or haven’t had your hearing tested lately, you owe it to your overall health to schedule a hearing evaluation with a qualified hearing healthcare professional as soon as possible. Untreated hearing loss can lead to depression and anxiety. It is also related to other serious medical conditions such as cardiovascular disease, diabetes, dementia and Alzheimer’s disease. Consult your family physician for a referral or visit Healthy Hearing’s Find a Clinic listing to find a hearing care professional in your community.