Regenerative Medicine in Cochlear Implantation

Abstract

Cochlear implantation improves hearing and speech ability in patients with profound or severe sensorineural hearing loss. However, its effects are limited when there is a primary auditory neuron response deficiency. To overcome this limitation, several strategies have been developed for the preservation or regeneration of spiral ganglion cells, i.e., primary auditory neurons. Among those strategies, the administration of neurotrophic factors and the transplantation of neural stem or progenitor cells are two of the most promising. To preserve spiral ganglion cells, neurotrophic factors can be delivered into the cochlea by various methods including direct infusion, viral vectors, transplantation of neurotrophic factor-transfected cells, and transplantation of neural stem cells. To regenerate spiral ganglion cells, transplantation of stem or progenitor cells is required. The most efficient method is the transplantation of pluripotent stem cells that are induced toward neural or otic fate in vitro before transplantation.