The relationship between serum miR-21 levels and left atrium dilation in elderly patients with essential hypertension

 BACKGROUND  MicroRNA-21 (miR-21) is related to hypertension and cardiac remodelling. Left atrium (LA) dilation is highly sensitive to small haemodynamic changes in the left ventricle (LV) that are induced by hypertension. This study aimed to elucidate the relationship between miR-21 expression and LA dilation in elderly patients with essential hypertension (EH).

 METHODS  In this cross-sectional study, one hundred elderly patients with EH were recruited for the study. According to their left atrium diameters (LADs), the patients were divided into the LA dilation group 42 patients (42%) and the no-LA dilation group 58 patients (58%). The serum levels of miR-21 and chemical biomarkers used in the clinic, such as creatinine, blood urea nitrogen, uric acid, fasting blood glucose, total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), very-low-density lipoprotein cholesterol, Lp(a), apolipoprotein A1 (apoA1), and apolipoprotein B, were measured. All the patients underwent echocardiographic examination, and the LAD, interventricular septum (IVS), right atrium diameter (RAD), right ventricle diameter (RVD), left ventricular end-systolic diameter (LVESD), left ventricular end-systolic diameter (LVEDD) and left ventricular ejection fraction (LVEF) were measured.

 RESULTS The levels of miR-21 8.02 (5.21, 14.39) vs. 6.05 (3.81, 8.95), P = 0.011 and LVEF (67.02 ± 3.82 vs. 64.14 ± 4.43, P = 0.001) were higher in the LA dilation group. The levels of creatinine 70.40 (64.45, 80.15) vs. 63.9(60.1, 73.43), P = 0.020 were higher in the no-LA dilation group. The levels of HDLC (r = – 0.209, P = 0.037), apoA1 (r = –0.269, P = 0.007) and RAD (r = 0.203, P = 0.043) were significantly correlated with miR-21 expression. The LAD was significantly correlated with the RAD (r = 0.287, P = 0.004), RVD (r = 0.450, P < 0.001), LVEDD (r = 0.248, P = 0.013) and LVEF (r = 0.232, P = 0.020). Multivariate logistic regression revealed that miR-21 significantly influenced LA dilation in elderly patients with EH (P < 0.05).

 CONCLUSIONS Circulating serum levels of miR-21 are increased in elderly patients with EH with LA dilation. miR-21 levels are significantly correlated with LA dilation in elderly patients with EH, and miR-21 may be a factor related to the clinical pathophysiological occurrence of and treatment for the progression of hypertension-related early heart damage in EH patients.