New study through Pitt School of Medicine developing medication to treat noise-induced hearing loss

Researchers at Pitt have recently discovered that medication could be used to help alleviate temporary or permanent hearing loss from noise. 

“The bottom line is if we have a drug that could protect from hearing loss, that will be huge,” Thanos Tzounopoulos, senior author and director of the Pittsburgh Hearing Research Center at Pitt’s School of Medicine, said.

Brandon Bizup, first author and Pitt School of Medicine postdoctoral student, noted that roughly 17% of people have some degree of noise-induced hearing loss.

“That’s a huge proportion of people that are affected by it,” Bizup said. “Obviously not all of those people experience a sudden onset of major hearing loss, but they still could benefit from treatment.”

Tzounopoulos said the fact that noise-induced hearing loss is a “very common problem” motivated him and other researchers to “figure out what the mechanics of hearing loss are.”

“The precise mechanisms that lead to this hearing loss are not fully clear,” Tzounopoulos said. “As a result, there is not an FDA-approved drug or something that could immediately help.”

The team of researchers has worked on this hearing loss study for about six years. Through performing experiments on mice, they found that there is a correlation between zinc levels and noise-induced hearing loss. 

“Zinc has a signaling capacity, and when the signal gets dysregulated, it can lead to cell death and degeneration,” Tzounopoulos said. “We wanted to see if that’s part of the process in cochlear damage in damage in the inner ear after noise trauma.”

The researchers found that zinc levels in the inner ear increase after exposure to loud noises. This increase in zinc “leads to cellular damage and disrupts normal cell-to-cell communication.”

“It’s known from some other studies that there’s a certain pool of zinc that can cause damage to be exacerbated after a neurological injury like stroke models,” Bizup said. “No one ever looked at it in terms of hearing loss and in the auditory system in general.”

This drug is meant to be a preventative drug, so users would take the medicine before loud noise exposure. However, the researchers said they hope users could also take the drug not long after the event to restore hearing loss. 

“Ideally, the drug would be in pill form,” Amantha Thathiah, assistant professor of neurobiology, said. “But initially, it would probably be some kind of local application in your ear.”

Tzounopoulos added that the drug being in pill form would allow the user to take it before an expected loud event.

“The best case scenario would be that you have a pill you can take before you go to combat, a concert, a stadium, anything that is very loud and it would help combat hearing loss,” Tzounopoulos said. 

During the experiment on mice, drugs that act as “zinc-binding agents” were used. These zinc-binding agents are called key layers, which are essentially like a zinc sponge. 

“The exposed mice that were treated with the zinc sponge had a better hearing recovery after the noise exposure than the mice that weren’t treated with the zinc sponge,” Bizup said. 

Bizup said there are “a lot of next steps” in the research, but an important one is figuring out the time frame that the medicine should be taken before or after noise exposure. 

“We want to focus on the timing model, so pretreating with the zinc sponge, and then causing the zinc dysregulation with the noise exposure and then testing the hearing afterwards,” Bizup said. “But it’s not necessarily translatable to patients since we’re doing these experiments with mice.”

Thathiah said she agreed with Bizup that “establishing a timing window” is an important next step.

“We want to see whether or not it is possible to reestablish or restore hearing after noise-induced hearing loss, and if so, what the time frame is for administering the medicine following the hearing loss,” Thathiah said.

Bizup also noted that it is important to figure out “exactly what kinds of drugs are tolerable.”

“Since we’re doing these experiments on mice, we have more flexibility in what kinds of drugs we can use,” Bizup said. “We need to figure out toxicity parameters and what kind of dosages are needed.”

Tzounopoulos said one of the next steps in this research is drug discovery and development.

“We want to work with the medicinal chemists and create a safe compound that could become a drug that could trap or capture zinc,” Tzounopoulos said. 

Thathiah said although experiencing noise-induced hearing loss is not a “death sentence,” it can still majorly affect people’s lives. 

“If you have the option of treatment after exposure to a very loud noise, it would be life-changing,” Thathiah said. “You wouldn’t necessarily be losing one of your very crucial senses. To have that kind of restoration of hearing loss is huge.”