Differential Expression of Na/K-ATPase in the Human Saccule of Patients With and Without Otologic Disease

Abstract

Hypothesis Na+, K+-ATPase (Na/K-ATPase) α1 subunit expression in the saccule of patients diagnosed with otologic disease is different compared with normal controls. Background We have recently characterized changes in the expression of Na/K-ATPase α1 subunit in the normal and pathological cochlea; however, no studies have determined the distribution Na/K-ATPase α1 subunit in the human saccule. The present study uses archival temporal bones to study the expression Na/K-ATPase α1 subunit in the human saccule. Methods Archival celloidin formalin fixed 20-micron thick sections of the vestibule from patients diagnosed with Menière's disease (n = 5), otosclerosis (n = 5), sensorineural hearing loss, and normal hearing and balance (n = 5) were analyzed. Sections containing the saccular macula were immunoreacted with mouse monoclonal antibodies against Na/K-ATPase α1 subunit. Micrographs were acquired using a high-resolution digital camera coupled to a light inverted microscope. Results In the normal human saccule vestibular sensory epithelium, Na/K-ATPase α1 immunoreactivity (IR) was present in nerve fibers and calyces that surround type I vestibular hair cells and nerve terminals. The transition epithelium cells were also Na/K-ATPase α1 immunoreactive. Comparison between normal and pathological specimens showed that there was a significant reduction of Na/K-ATPase α1 IR in the saccule vestibular sensory epithelium from patients with Menière’s disease, otosclerosis, and sensorineural hearing loss. Conclusions The decrease of Na/K-ATPase-IR α1 in the saccule vestibular sensory epithelium from patients with otopathologies suggests its critical role in inner ear homeostasis and pathology.