MicroRNA-503-5p improves carotid artery stenosis by inhibiting the proliferation of vascular smooth muscle cells

Carotid artery stenosis (CAS) is a common arteriosclerotic vascular disease affected by vascular smooth muscle cells (VSMCs). The aim of the present study was to investigate the expression and diagnostic value of microRNA (miR)-503-5p in asymptomatic patients with CAS and to further explore the effect of miR-503-5p on VSMC proliferation. The levels of miR-503-5p in the serum of 62 asymptomatic patients with CAS and 60 healthy controls were detected by reverse transcription-quantitative PCR. The association between miR-503-5p and the clinical characteristics of the patients was analyzed using the χ(2) test. A receiver operating characteristic curve was drawn to evaluate the diagnostic value of miR-503-5p to distinguish asymptomatic patients with CAS from healthy controls. Finally, miR-503-5p inhibitors and mimics were transfected into VSMCs in vitro to detect the effect of miR-503-5p on the proliferation ability through Cell Counting Kit-8 assays. The serum levels of miR-503-5p in asymptomatic patients with CAS were significantly reduced as compared with those in healthy individuals. The expression levels of miR-503-5p were significantly associated with diabetes and arterial stenosis. Furthermore, the area under the ROC curve was 0.817, the specificity was 79.03% and the sensitivity was 83.30%, which proved that miR-503-5p had a high diagnostic accuracy in patients with CAS. Finally, the in vitro proliferation assay indicated that overexpression of miR-503-5p significantly inhibited the proliferation of VSMCs. In conclusion, miR-503-5p is a potential diagnostic biomarker for asymptomatic CAS and overexpression of miR-503-5p may inhibit the proliferation of VSMCs and improve CAS.