Abstract: Objective This study was conducted to explore clinical implications of serum miR-122, miR-140-5p and miR-34alevels in patients with nonalcoholic fatty liver disease (NAFLD). Methods 104 patients with NAFLD and 60 healthy individuals for physical examination were encountered in our hospital between December 2021 and December 2023, and liver biopsies were performed in all patients with NAFLD. Serum miR-122, miR-140-5p and miR-34a levels were detected by real-time fluorescence quantitative RT-PCR. Risk factors of nonalcoholic steatohepatitis (NASH) were analyzed by multivariate Logistic regression. Receiver operating characteristic curve (ROC) and the area under the curve (AUC) were applied to evaluate diagnostic efficacy of serum miR-122, miR-140-5p, and miR-34a levels for NASH occurrence. Results Of 104 patients with NAFLD, NASH was found in 43 cases and simple fatty liver (SFL) was found in 61 cases based on NAFLD activity scores; serum miR-122 and miR-34a levels in NASH patients were (8.1±1.3) and (1.8±0.4), both significantly higher than [(2.6±0.7) and (1.3±0.4), respectively, P<0.05] in SFL patients or [(1.3±0.2) and (0.8±0.2), respectively, P<0.05] in healthy control, while serum miR-140-5p level in NASH patients was (24.1±5.1) ×10^-4, significantly lower than [(71.2±11.3) ×10^-4, P<0.05] in SFL patients or [(258.9±71.5) ×10^-4, P<0.05] in healthy persons; multivariate Logistic regression analysis showed that BMI (OR=1.793,95%CI: 1.352-2.378), ALT (OR=1.522,95%CI: 1.127-2.055), AST (OR=1.419,95%CI: 1.205-1.671), TG (OR=1.715,95%CI:1.194-2.463), LDL-C (OR=1.537,95%CI:1.264-1.869), HDL-C (OR=1.631,95%CI:1.207-2.204), miR-122 (OR=1.409,95%CI:1.228-1.617), miR-140-5 p (OR=0.639,95%CI:0.477-0.856) and miR-34a (OR=1.745,95%CI:1.162-2.621) were all the independent risk factors for NASH (P<0.05); ROC analysis showed that the AUC of combined serum miR-122, miR-140-5p and miR-34alevels for the diagnosis of NASH was 0.954, with the sensitivity of 88.4%, thespecificity of 90.2% and the accuracy of 89.4%, much superior to any one of the parameters alone (P<0.05). Conclusion Serum miR-122, miR-34aand miR-140-5p levels might help screening of patients with NASH in population of NAFLD, which needs further clinical investigation.

Key words: Nonalcoholic fatty liver disease, Nonalcoholic steatohepatitis, MicroRNA-122, MicroRNA-140-5p, MicroRNA-34a, Diagnosis