Circulating miR-122 and miR-29a with Non-Invasive Markers of Hepatic Steatosis and Fibrosis in Individuals with Metabolic Syndrome

Background/Objectives: Circulating microRNAs (miRNAs) are potential minimally invasive biomarkers of metabolic dysfunction-associated steatotic liver disease (MASLD). miR-122 is associated with hepatocyte homeostasis and injury, whereas miR-29a is involved in hepatic fibrogenesis. This study evaluated associations of circulating miR-122 and miR-29a with metabolic, inflammatory, and non-invasive hepatic steatosis and fibrosis indices in individuals with metabolic syndrome (MetS). Methods: Seventy-three adults with MetS were evaluated. Circulating miR-122 and miR-29a were quantified by RT-qPCR. Hepatic steatosis was assessed using the Hepatic Steatosis Index (HSI) and Zhejiang University Index (ZJU), while fibrosis risk was evaluated using the Fibrosis-4 Index (FIB-4), AST-to-Platelet Ratio Index (APRI), and NAFLD Fibrosis Score (NFS). Correlation, multiple linear regression, and receiver operating characteristic (ROC) analyses were performed. Results: Overall, 79.5% of participants had HSI ≥ 36. Neither miR-122 nor miR-29a differed significantly between HSI or age-adjusted FIB-4 categories. miR-122 correlated positively with lymphocyte count (ρ = 0.334; p = 0.029), while no other significant correlations were observed. miR-29a showed nonsignificant inverse correlations with FIB-4, APRI, and NFS. In adjusted models, no hepatic index was independently associated with either miRNA. ROC analyses showed limited discrimination, with AUCs of 0.560–0.604 for HSI and 0.560–0.587 for FIB-4. Conclusions: Circulating miR-122 and miR-29a showed limited associations with non-invasive indices of hepatic steatosis and fibrosis and poor discriminatory performance when assessed individually in individuals with MetS. Further studies using more specific liver assessment methods and multimarker approaches are needed to clarify their clinical utility.