Abstract

Acute coronary syndrome (ACS) is the main manifestation of cardiovascular disease and the primary cause of adult hospitalization in China. There is an urgent demand for novel biomarkers for the diagnosis of ACS. Although plasma cysteine‑rich protein 61 (Cyr61) has been previously reported to be accurate for ACS diagnosis, the accuracy of exosomal Cyr61 in ACS diagnosis remains unknown. In the present study, the aim was to assess the potential of applying exosomal Cyr61 in ACS diagnosis and to explore the role of Cyr61 in vascular remodeling in vitro. The abundance of Cyr61 in plasma‑derived exosomes from patients with unstable angina pectoris (UAP), acute myocardial infarction (AMI) patients in addition to those isolated from healthy individuals were detected using an ELISA kit. The association between exosomal Cyr61 levels and clinical characteristics of ACS patients was analyzed through χ² test, Fisher's exact test and Student's t‑test. Receiver operating characteristic (ROC) curve analysis was used to determine the accuracy of using exosomal Cyr61 as a biomarker of ACS diagnosis. Furthermore, independent predictors of the existence of ACS were investigated through a multivariate analysis. Subsequently, the role of Cyr61 on vascular remodeling was evaluated in vascular smooth muscle cells (VSMCs) upon oxidized low‑density lipoprotein (ox‑LDL) treatment by performing Cyr61 knockdown, Cell Counting Kit‑8, flow cytometry and Transwell assays. Exosomal Cyr61 expression was found to be significantly elevated in patients with ACS compared with that in healthy individuals. In addition, exosomal Cyr61 levels were associated with sex, family history of ACS and glucose levels. ROC curve analyzes revealed that exosomal Cyr61 expression could be used to differentiate patients with UAP, AMI and ACS from healthy individuals. Furthermore, exosomal Cyr61 levels were independently correlated with the existence of ACS. In vitro, Cyr61 expression was demonstrated to be s