Increased Monocyte Chemotactic Protein-1 Accompanying Pro-Inflammatory Processes are Associated with Progressive Hearing Impairment and Bilateral Disability of Meniere’s Disease

Abstract

Background: The progression of hearing impairment and the bilateral involvement of Meniere’s disease (MD) may depend on the disease duration and aging. Recent studies reported that MD might involve dysfunction of the microvascular circulation damaged due to inflammatory changes. Objectives: The aim of this study was to determine that the progress of the MD’s hearing impairment and bilateral disability may be associated with the pathogenesis of several pro-inflammatory processes. Patients and Methods: We recruited 30 unilateral MD patients (56.8 ± 14.7 years old), 7 bilateral MD patients (65.3 ± 13.9 years old), and 17 age-matched control subjects (53.5 ± 14.4 years old, p > 0.05). We measured the plasma vascular endothelial growth factor (VEGF), plasma interleukin-6 (IL-6), plasma tumor-necrosis factor α (TNFα), and plasma monocyte chemotactic protein-1 (MCP-1). Results: The bilateral MD group and the unilateral MD group had higher plasma MCP-1 (204.7 ± 41.0 pg/mL and 169.5 ± 32.0 pg/mL) than the control group (149.2 ± 30.7 pg/mL) (p < 0.05). There was no significant difference in plasma TNFα, IL-6, and VEGF among 3 groups (p > 0.05). There was a strong correlation between the plasma MCP-1 and age in MD patients (r = 0.58, p < 0.01); however, no significant correlation between the plasma MCP-1 and age was found in control subjects (p > 0.05). The plasma MCP-1 significantly correlated with the average hearing level of 500, 1,000, 2,000, and 4,000 Hz, and the maximum slow phase eye velocity in caloric test in the better side (p < 0.05). Also, the plasma MCP-1 showed significant positive correlations with the plasma IL-6 (r = 0.49, p < 0.01) and plasma TNFα (r = 0.32, p < 0.05) in MD group. Conclusions: Our results suggest that the increased plasma MCP-1 accompanying pro-inflammatory processes are associated with the progression of the hearing impairment and the bilateral disability of MD.