Laminin-coated electrodes improve cochlear implant function and post-insertion neuronal survival

• Published in: Neuroscience 2019-07, Vol.410, p.97-107
• Main Authors: Bas, Esperanza, Anwar, Mir R., Goncalves, Stefania, Dinh, Christine T., Bracho, Olena R., Chiossone, Juan A., Van De Water, Thomas R.
• Format: Article
• Language: English
• Subjects: Animals; Animals, Newborn; Cell Survival - physiology; Cells, Cultured; cochlear implants; Cochlear Implants - standards; Electrodes, Implanted - standards; laminin; Laminin - administration & dosage; Laminin - chemistry; Male; neuritic outgrowth/guidance; Neurons - physiology; Organ of Corti - cytology; Organ of Corti - physiology; Random Allocation; Rats; Rats, Inbred BN; Rats, Sprague-Dawley; Schwann cells; spiral ganglion neurons
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2019.04.048

The benefits of Cochlear implant (CI) technology depend among other factors on the proximity of the electrode array to the spiral ganglion neurons. Laminin, a component of the extracellular matrix, regulates Schwann cell proliferation and survival as well as reorganization of actin fibers within their cytoskeleton, which is necessary for myelination of peripheral axons. In this study we explore the effectiveness of laminin-coated electrodes in promoting neuritic outgrowth from auditory neurons towards the electrode array and the ability to reduce acoustic and electric auditory brainstem response (i.e. aABR and eABR) thresholds. In vitro: Schwann cells and neurites are attracted towards laminin-coated surfaces with longer neuritic processes in laminin-coated dishes compared to uncoated dishes. In vivo: Animals implanted with laminin-coated electrodes experience significant decreases in eABR and aABR thresholds at selected frequencies compared to the results from the uncoated electrodes group. At 1 month post implantation there were a greater number of spiral ganglion neurons and neuritic processes projecting into the scala tympani of animals implanted with laminin-coated electrodes compared to animals with uncoated electrodes. These data suggest that Schwann cells are attracted towards laminin-coated electrodes and promote neuritic outgrowth/ guidance and promote the survival of spiral ganglion neurons following electrode insertion trauma. •Laminin promotes Schwann cell and neuritic outgrowth from spiral ganglion explants.•Laminin coating of electrodes decreases aABR and eABR thresholds in implanted animals.•Laminin coating of electrodes supports post-implantation survival of spiral ganglion neurons.