A Rice University study has found that the aspirin-like drug diflunisal blocks the action of prestin, a key protein that is required for hearing.
The research, which is available online in the open-access journal PLOS ONE, stemmed from a 2015 Rice study that screened more than a half-dozen nonsteroidal anti-inflammatory drugs, or NSAIDs, for possible interactions with the protein prestin. Prestin is a highly specialized protein that drives the action of outer hair cells in the cochlea, an inner-ear organ that allows people and animals to hear.
"Taking too much aspirin can cause temporary deafness, and researchers discovered more than a decade ago that this happens because salicylate, one of the primary metabolites of aspirin, interferes with prestin," said study lead author Guillaume Duret, a research scientist in Rice's Department of Electrical and Computer Engineering. "Given the number of commonly used NSAIDs that operate in a similar way to aspirin, it seemed like a good idea to find out whether they also might inhibit prestin."
Duret said diflunisal was the only drug in the test that blocked the action of prestin. He said the findings suggest that the inhibition occurs by competing with chloride ions in prestin, a mechanism that is similar to what has been proposed for salicylate. The study also found that the dosage needed to induce a reaction was less than the aspirin dose required to induce a similar reaction.
Diflunisal is primarily prescribed as a mild pain killer and an anti-inflammatory for arthritis. But Duret said the findings come at an important time because the medical community is considering repurposing diflunisal as a possible treatment for both cancer and amyloid polyneuropathy.
"So far, it's been used in a pill form that is ingested, and the known side effects are for relatively small doses, like as if you were taking aspirin," Duret said. "For greater doses that are perhaps injected, the side effects may not yet be known."
He conducted the study's experiments in 2015 with two of the world's leading experts on prestin and outer hair cells, Rice bioengineer Rob Raphael and Baylor College of Medicine molecular biologist Fred Pereira.
