Anatomical and functional studies of isolated vestibular neuroepithelia from Meniere's Disease patients

Abstract

Surgical removal of vestibular end organs is a final treatment option for people with intractable Menieres Disease. We describe the use of surgically excised vestibular neuroepithelium from patients with Menieres Disease for 1) anatomical investigation of hair cell and nerve fibres markers using immunohistochemistry and 2) functional studies using electrophysiological recordings of voltage-activated currents. Our data shows considerable reduction in and disorganization of vestibular hair cells in the cristae ampullares while nerve fibres are in contact with remaining sensory receptors but appear thin in regions where hair cells are absent. Electrophysiological recordings of voltage-activated potassium currents from surviving hair cells demonstrate normal activity in both type I and type II vestibular hair cells. In addition, current-voltage plots from type I vestibular hair cells are consistent with the presence of a surrounding calyx afferent terminal. These data indicate surviving hair cells in Menieres Disease patients remain functional and capable of transmitting sensory information to the central nervous system. Determining functionality of vestibular receptors and nerves is critical for vestibular implant research to restore balance in people with Menieres Disease. Summary StatementThis study shows, that while there is significant hair cell loss in Menieres Disease patients, surviving type I and type II vestibular hair cells have normal voltage-activated conductances.