(0937) Glucocorticoid Receptors in the Human Vestibular Endorgans Obtained From Ménière's Disease Patients

Introduction: Glucocorticoid receptors (GCR) and glucocorticoids have been studied in mouse, rat, guinea pig, and human inner ears. However, they have yet to be localized in human vestibular endorgans. In this study, GCRs were localized in human vestibular endorgans obtained from ablative surgery.

Methods: Formalin-fixed, 20-μm cryostat sections of cristae and maculae were obtained from patients who required transmastoid labyrinthectomy for intractable vertigo secondary to Meniere’s disease (MD) (n = 5, 3 male, 2 female, ages 50-70) and acoustic neuroma (AN) (n = 4, 2 male, 2 female, ages 45-65). These samples were immunofluorescence (IF) stained with GCR rabbit polyclonal antibodies and glial fibrillary acidic protein monoclonal antibodies (GFAP) to identify supporting cells (SCs) in the sensory epithelia. Digital fluorescent images were acquired using a high-resolution laser confocal microscope.

Results: In MD specimens, GCR-IF was observed in the cell nuclei of vestibular hair cells (VHCs), SCs, stromal cells, and vascular endothelial cells (VECs) and pericytes of the stromal vasculature. Amongst the MD vestibular endorgans, there were no differences in overall GCR-IF. Within the vestibular sensory epithelium, SCs exhibited greater GCR-IF than VHCs. In stromal vasculature, VECs and pericytes exhibited strong GCR-IF. In AN vestibular endorgans, GCR-IF was present in the cell nuclei of VHCs, SCs, stromal cells, VECs, and pericytes. GCR-IF in AN cell nuclei was uniform and less intense than in MD vestibular endorgans.

Conclusions: GCR-IF distribution was ubiquitous in human vestibular endorgan cell nuclei obtained from MD and AN. However, MD specimens exhibited greater GCR-IF than AN specimens. The elevated GCR-IF, in conjunction with our previous studies (Ishiyama et al., 2018, Front. Physiology 9:1068), suggest SCs, VECs, and pericytes in MD vestibular endorgans may be under oxidative stress. The differential GCR expression found in MD and AN vestibular endorgans may help guide the therapeutic utilization of glucocorticoid administration in inner ear pathologies.