Expression and role of miR-126-3p and RAAS biomarkers in primary hypertension

To compare plasma levels of miR-126-3p between patients with essential hypertension (EH) and healthy individuals, and to investigate its correlation with renin–angiotensin–aldosterone system (RAAS) biomarkers. 29 healthy controls and 71 EH patients were enrolled. Total RNA, including miRNA, was extracted from plasma. Relative expression of miR-126-3p was determined by qRT-PCR. The discriminative ability of miR-126-3p and a combined panel was evaluated using ROC curves. The relative expression of miR-126-3p was significantly higher in the EH group (3.20 ± 2.15) than in the healthy group (1.54 ± 1.27, P < 0.001). Spearman correlation showed a significant negative correlation between miR-126-3p and serum ACE2 activity (r = − 0.205, p = 0.041). The AUC of a combined indicator (miR-126-3p, AngII, LDL-C, TC) was 0.859 (95% CI: 0.769–0.950, P < 0.001). Stepwise regression identified AngII, TC, LDL-C, and miR-126-3p as significant ( P < 0.05), although collinearity was within an acceptable range (VIF < 5). miR-126-3p is significantly upregulated in the peripheral blood of EH patients and correlates negatively with ACE2. The combined panel shows moderate exploratory discriminative ability. However, due to the absence of continuous blood pressure data, no claim of added value over blood pressure measurement can be made. The potential role of miR-126-3p in modulating the RAAS counter‑regulatory axis requires further validation.