Stem cells and molecular strategies to restore hearing.

Hearing loss is a costly and growing problem for the elderly population worldwide with millions of people being affected. There are currently two prosthetic devices available to minimize problems associated with the two forms of hearing loss: hearing aids that amplify sound to overcome middle ear based conductive hearing loss and cochlear implants that restore some hearing after neurosensory hearing loss. The current presentation provides information on the treatment of neurosensory hearing loss. Although the cochlear implant solution for neurosensory hearing loss is technologically advanced; it still provides only moderate hearing capacity in neurosensory deaf individuals. Inducible stem cells and molecular therapies are appealing alternatives to the cochlear implant and may provide more than a new form of treatment as they hold the promise for a cure. To this end, current insights into inducible stem cells that may provide cells for seeding the cochlea with the hope of new hair cell formation are being reviewed. Alternatively, similar to induction of stem cells, cells of the flat epithelium that remains after hair cell loss could be induced to proliferate and differentiate into hair cells. In either of these strategies, hair cell specific genes known to be essential for hair cell differentiation or maintenance such as ATOH1, POU4F3, GFI1, and miRNA-183 will be utilized with the hope of completely restoring hearing to all patients with hearing loss.