Serum microRNA-122 as a potential biomarker for early detection and monitoring of type 2 diabetes mellitus: a cross-sectional study

Introduction : MicroRNAs (miRNAs) are small noncoding RNAs with transcriptional repressive properties. Type 2 diabetes mellitus (T2DM) is closely associated with endothelial dysfunction and altered molecular signaling. Although microRNA-122 (miR-122) is highly abundant in the liver and contributes to lipid homeostasis, its significance in predicting long-term metabolic disease risk remains insufficiently understood. Materials and methods : Circulating miR-122 levels were quantified in 85 patients with T2DM, stratified into: group 1: manifest T2DM (n=50), and group 2: T2DM diagnosed according to WHO criteria (n=35). Results were compared with 47 healthy controls. To assess the long-term predictive value of miR-122, findings were further compared with data from the prospective Bruneck study (n=810, baseline 1995). Multivariable Cox regression models were used to evaluate the association between log-transformed miR-122 levels and incident T2DM over a follow-up period of up to 15 years. Results : Circulating miR-122 was significantly associated with T2DM status, with patient groups demonstrating altered expression patterns suggestive of its potential involvement in metabolic dysregulation. Notably, reduced miR-122 levels in patient groups emerged as a possible indicator of T2DM. In the Bruneck cohort, each 1-standard deviation (SD) increase in log(miR-122) was associated with a 37% higher risk of developing T2DM (HR=1.37, 95% CI: 1.03–1.82, p =0.021) during the 15-year follow-up. Conclusion : Decreased miR-122 levels may characterize individuals with existing T2DM, elevated long-term levels were predictive of future diabetes onset in a population-based cohort. These results underscore the utility of miR-122 as a promising biomarker for early identification of individuals at increased risk for T2DM.