Sialyllactose Preserves Residual Hearing after Cochlear Implantation

Abstract In individuals with hearing loss, protection of residual hearing is essential following cochlear implantation to facilitate acoustic and electric hearing. Hearing preservation requires delivery of the optimal quantity of a pharmacological agent using osmotic pumps. Several studies have reported variable hearing outcomes with osmotic pump-mediated steroid delivery. Several new drugs, including sialyllactose (SL), can prevent tissue overgrowth. In the present study, we used an animal model to simulate the damage due to electrode insertion during cochlear implantation. The positive effects of the pharmacological agent SL against insults were evaluated in vitro using HEI-OC1 cells. SL was delivered using osmotic pumps to prevent loss of the residual hearing in this animal model. We demonstrated hearing deterioration and tissue fibrosis and ossification in this model. Increased gene expressions of inflammatory cytokines were identified in the cochleae following dummy electrode insertion. Following the administration of SL, insertion led to a decrease in hearing threshold shifts, tissue reactions, and inflammatory markers. These results emphasize the possible role of SL in hearing preservation and improve our understanding of the mechanism underlying hearing loss after cochlear implantation.