title: Novel drug delivery systems for inner ear protection and regeneration after hearing loss.
abstract: BACKGROUND
  A cochlear implant, the only current treatment for restoring auditory perception after severe or profound sensorineural hearing loss (SNHL), works by electrically stimulating spiral ganglion neurons (SGNs). However, gradual degeneration of SGNs associated with SNHL can compromise the efficacy of the device.
  
  
  OBJECTIVE
  To review novel drug delivery systems for preserving and/or regenerating sensory cells in the cochlea after SNHL.
  
  
  METHODS
  The effectiveness of traditional cochlear drug delivery systems is compared to newer techniques such as cell, polymer and gene transfer technologies. Special requirements for local drug delivery to the cochlea are discussed, such as protecting residual hearing and site-specific drug delivery for cell preservation and regeneration.
  
  
  CONCLUSIONS
  Drug delivery systems with the potential for immediate clinical translation, as well as those that will contribute to the future of hearing preservation or cochlear cellular regeneration, are identified.
authors.affiliation: Bionic Ear Institute, 384 Albert Street, East Melbourne, Victoria 3002, Australia. rrichardson@bionicear.org
authors.forename: Rachael T
authors.initials: RT
authors.lastname: Richardson
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Wise
authors.forename: Jacqueline K
authors.initials: JK
authors.lastname: Andrew
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: O'Leary
mesh_terms: D064987:Cell- and Tissue-Based Therapy / Q000379:methods; D003054:Cochlear Implants; D016503:Drug Delivery Systems; D007758:Ear, Inner / Q000187:drug effects / Q000503:physiopathology; D004558:Electric Stimulation; D018014:Gene Transfer Techniques; D006319:Hearing Loss, Sensorineural / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D009414:Nerve Growth Factors / Q000378:metabolism / Q000494:pharmacology; D009416:Nerve Regeneration / Q000187:drug effects*; D013136:Spiral Ganglion / Q000503:physiopathology
chemical_list: D009414:Nerve Growth Factors