The antiviral medication Tamiflu appears to have eased noise-induced hearing loss in mice. While research in people is required, this could open the door to a treatment for a common type of deafness.
people worldwide. Prevention focuses on just avoiding loud sounds where possible, with treatments being limited to hearing aids and implants.
Only one drug, called sodium thiosulfate, has ever been approved to prevent any type of hearing loss. (FDA) in 2022, but it is only available for children taking a form of chemotherapy called cisplatin, which can damage the ear by inducing cell death.
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Seeking more options, at Creighton University in Nebraska and her colleagues worked their way through a library of 1300 drugs that had been FDA approved to protect against cisplatin damage to any part of the body. The scientists tested whether any of these drugs shielded inner ear cells from harm in test tube experiments, which led them to oseltamivir phosphate, better known as Tamiflu.
To assess whether oseltamivir phosphate might treat noise-induced hearing loss, the team placed mice into a sound-tight chamber and exposed them to 100 decibels of noise 鈥� or motorcycle 鈥� over 2 hours. The mice were then split into four groups, three of which received varying doses of oseltamivir phosphate within 24 hours of the noise exposure, while the fourth group acted as a control.
Compared with the control group, the mice that received the highest dose of oseltamivir phosphate had less diminishing of their auditory brainstem response, defined as the activity level of a pathway of neurons that connect the inner ear to the brain鈥檚 major hearing hub, called the inferior colliculus. Lower doses were less effective.
Through a series of further experiments, the researchers found that oseltamivir phosphate protects against cochlear synaptopathy 鈥� a loss of synapses, the points at which neurons connect and communicate, in the auditory nerve pathway that links inner ear cells to the brain.
They also found that oseltamivir phosphate lowers levels of CD45 immune cells, markers of inflammation that are elevated following noise exposure. Its anti-inflammatory properties also suppress levels of a protein called ERK1/2, which is associated with inflammation in cisplatin and noise-induced hearing loss.
鈥淲hile promising, it is a study in mice and so the drug effects in humans would need to be established before we can get excited about its potential to reduce or prevent hearing loss,鈥� says at the University of Melbourne, Australia. 鈥淏ut if they cross over, this treatment could prevent significant suffering and disability for many people.鈥�
However, very distinct biological processes underlie different forms of hearing loss, and oseltamivir phosphate may not be appropriate for all of them, says Sarant. 鈥淐ardiovascular disease causes hearing loss by restricting blood supply to the ear, and it seems unlikely that Tamiflu could address this,鈥� she says.
bioRxiv
