Potential of circulating miR-29a and miR-142-5p as biomarkers for diabetic nephropathy: a cross-sectional study.

Background: Diabetic nephropathy (DN), a major microvascular complication of type 2 diabetes mellitus (T2DM), is a leading cause of end-stage renal disease. Early diagnosis remains challenging because conventional biomarkers have limited sensitivity. Circulating microRNAs, including miR-29a and miR-142-5p, have recently emerged as promising diagnostic candidates in several diseases. This study aimed to compare serum levels of miR-29a and miR-142-5p between T2DM patients with and without DN and to evaluate their potential diagnostic utility. Methods: This cross-sectional, single-center observational study enrolled 164 patients with T2DM and 164 healthy controls. Participants with T2DM were stratified into three subgroups according to urinary albumin-to-creatinine ratio (UACR). Serum miR-29a and miR-142-5p expression levels were measured using quantitative reverse transcription PCR. Clinical parameters were statistically analyzed, and logistic regression and receiver operating characteristic (ROC) curve analyses were performed to assess diagnostic performance. Results: Serum miR-29a and miR-142-5p levels were significantly elevated in patients with DN and increased progressively with disease severity. Both microRNAs were identified as independent risk factors for DN. A combined model incorporating miR-29a, miR-142-5p, and cystatin C improved diagnostic accuracy, with an area under the curve (AUC) of 0.939. Conclusion: Elevated serum miR-29a and miR-142-5p levels are strongly associated with DN progression, supporting their potential as non-invasive biomarkers for the diagnosis and risk stratification of patients with T2DM.