Reinstatement of Pendrin Expression Alleviates Fluctuating Hearing Loss

The mouse model Tg[E],Tg[R]Slc26a4"^A was further used to determine whether restoration of pendrin expression has a beneficial effect on hearing (Nishio et al. 2016). Doxycycline was administered from conception until E17.5, which resulted in the development of fluctuating and progressive hearing loss. Doxycycline was then reinstated either at P6 or at P30, which is before or after the establishment of the endoco- chlear potential and the onset of hearing. Reinstatement of pendrin expression at P6 alleviated hearing fluctuations, but reinstatement at P30 had no beneficial effect. An inverse correlation was noted between hearing thresholds and the amount of pendrin expression in the apical membrane of spindle-shaped cells. These observations underscore the importance of spindle-shaped cells for the homeostasis of stria vascularis, link deficient spindle-shaped cells to fluctuating hearing loss, and indicate that restoration of pendrin expression may be beneficial to ameliorate progression and fluctuations of hearing in individuals bearing mutations of SLC26A4.