Vascular and Neuroepithelial Histopathology of the Saccule in Humans With Diabetes Mellitus

Abstract

Hypothesis This study aimed to determine if there are quantitative differences in the neuroepithelium and microvasculature of the saccule between subjects with and without diabetes mellitus (DM). Background Histopathologic changes that may underlie the association between DM and vestibular dysfunction have not been characterized in humans. Methods Human temporal bones (HTBs) from 39 subjects with DM (n=16 type I DM (T1DM), n=23 type II DM (T2DM)) were compared to 40 group age-matched controls. Vessel wall thickness was measured from the saccular arteriole. Type I and type II vestibular hair cell (VHC) counts were performed on perpendicularly oriented saccular maculae using differential interference contrast microscopy (T1DM: 5 HTB/3 subjects; T2DM: 9HTB/8 subjects; controls: 25 HTB/20 subjects). Results The mean density of type I VHCs was 16 to 17% lower in the DM groups compared to controls (T1DM 52.21 [4.26], T2DM 53.3[5.34], control 63.14 [2.49] cells/mm2, p=0.02). There were no differences between T1DM, T2DM, and control groups in type II VHC density (T1DM 40.89 [5.17], T2DM 40.44 [6.93], control 42.80 [1.79] cells/mm2, p=0.92) or in mean vessel wall thickness (T1DM 2.23[0.62], T2DM 2.18 [0.53], control 2.00 [0.53] μm, p=0.26). Conclusion Neuroepithelial pathology, manifested as lower density of type I VHCs, was observed in the saccules of subjects with DM. Saccular microangiopathy, expressed as alterations in arteriole thickness, was not observed. These findings are consistent with histologic observations in animals with experimentally induced diabetes. DM may have a selective and deleterious effect on human vestibular sensory epithelia.

Vestibular evoked myogenic potentials in patients with diabetes mellitus

“…(2015), the authors determined the relative sparing of posterior SCC in diabetic patients. Kocdor et al. (2016) found a neuroepithelial pathology in the saccules of diabetic patients, manifested as a lower density of type I vestibular hair cells and concluded that selective and deleterious effects on human vestibular sensory epithelia may be present in DM.…”

Hypovitaminosis D, Low Bone Mineral Density, and Diabetes Mellitus as Probable Risk Factors for Benign Paroxysmal Positional Vertigo in the Elderly

“…However, a loss of sacculate type I hair cells has been described in human subjects with DM. 26,27 Glucose uptake is regulated in most tissues by the expression of glucose transporters on cell surfaces. 28 In DM, the saccule represents the main structure of the maze affected by pathological damage due to endolymphatic hydrops.…”

Utricular hypofunction in patients with type 2 diabetes mellitus

“…This is consistent with the finding in rats with long-term experimental diabetes of increased capillary diameters along with increased vascularisation of the saccule, suggesting greater stress on the capillary wall 20. In addition, the maculae of neither animal models nor human beings have shown microangiopathy, even if loss of type I hair cells has been described 20 21 , while evidence supports that dysregulated energy metabolism could also have a role in the vestibular dysfunction due to diabetes mellitus in the context of insulin signaling networks 22 .…”