A case-control study on proinflammatory genetic Polymorphisms on sudden sensorineural hearing loss

OBJECTIVES/HYPOTHESIS: Sudden sensorineural hearing loss (SSNHL) is strictly related to inner ear vascular injuries and recently to some atherosclerotic risk factors. The pathogenic role of inflammatory molecules in atherosclerosis is well established. However, there is little knowledge about the potential role of inflammatory cytokines and adhesion molecules on SSNHL etiology. STUDY DESIGN: The aim of this study was to evaluate the role of proinflammatory genetic polymorphisms of the MCP-1 (CCL2), E-selectin, and interleukin (IL)-6 gene in SSNHL patients. METHODS: We evaluated the frequency and distribution of selected single nucleotide polymorphisms of the MCP-1 (CCL2), E-selectin, and IL-6 gene in 87 SSNHL patients and 107 healthy controls. RESULTS: Our results did not show significant difference between the compared groups for MCP-1 and E-selectin genes, whereas a significant difference was reported for the IL-6 gene (P < .0001). CONCLUSIONS: The main finding of our study is that the 174G/G polymorphism (with a wider distribution of wt/wt genotype in SSNHL patients than in the healthy controls) of the IL-6 gene is significantly associated with the risk of SSNHL, which is consistent with a previous finding on serum levels of IL-6 in SSNHL. It is possible that the variant acts as a triggering agent of different lipidemia-related phenotypes. Both the -174G/G polymorphism and elevated IL-6 levels in SSNHL patients could suggest that IL-6 plays a role in the inner ear involvement by atherosclerotic inflammatory events.