Outer Hair Cell Molecular Protein, Prestin, as a Serum Biomarker for Hearing Loss: Proof of Concept

Hypothesis:At present there are no serum biomarkers available to monitor cochlear health in those at risk of hearing loss. Outer hair cells (OHCs) play an important role in cochlear function and are one of the cellular elements most vulnerable to damage, such as acoustic trauma. We hypothesized that an OHC-specific protein can serve as a biomarker for OHC damage in circulation.Methods:After assessing auditory function, rats were exposed to intense octave band noise for 2 to 3 hours. Auditory function was assessed 14 days after trauma. Blood samples were collected and prestin concentration was measured using enzyme-linked immunosorbent assay.Results:Circulating prestin was detectable in all control and noise-exposed animals. At 14 days after trauma, however, noise-exposed rats demonstrated statistically significant decrease in prestin concentrations compared with control animals.Conclusion:This work, for the first time, provides proof of concept that an otologic serum biomarker level can change after acoustic trauma and hearing loss. Our approach represents an entirely novel strategy in hearing diagnostics and has both research and clinical potential. Further work is needed to map out the temporal course of change in serum prestin concentrations after inner ear trauma, better define the relationship of serological and functional changes, and explore application to other etiologies of hearing loss (e.g., ototoxins).