Cardiovascular disease(CVD)is a major cause of human death and a serious threat to people's health.Therefore,it is very important to explore the early identification,diagnosis and effective treat-ment of CVD.The expression level of microRNA(miRNA)is related to many pathophysiological processes related to CVD,such as myocardial cell metabolism disorder,myocardial cell injury and myocardial fibrosis,which makes miRNA an important entry point for the diagnosis and treatment of CVD.MicroRNA-126(miR-126)is one of the most important biological markers in the miRNA family.It plays a role in protecting the myocardium by participating in angiogenesis,endothelial cell repair,and inhibition of inflammatory responses.This article reviewed the latest research progress on the mechanism,diagnostic significance and potential ther-apeutic value of miR-126 in the occurrence and development of various types of CVD.

Objective To investigate the molecular mechanism of miR-126-EPC-MPs in ameliorating oxygen glucose deprivation/reoxygenation (OGD/R) injury in cardiomyocytes.Methods The cardiomyocytes were used to establish the control and OGD/R injury models,and EPC-MPs and miR-126 mimic EPC-MPs treatments were administered respectively.The structural changes in cardiomyocyte organelles were assessed by transmission electron microscopy.ELISA was used to detect the expression levels of IL-6,TNF-α and HMGB-1 in cardiomyocytes.The protein and mRNA expression levels of Ang Ⅱ,caspase-6,eNOS,FOXO1,MPO,NF-κB,ERK1,LKB1,SIRT1,GRP78,GM130 and PGC-1α in cardiomyocytes after different treatments were detected by Western blot and quantitative PCR.Results The mitochondria structure in some cardiomyo-cytes of the OGD/R+miR-126 mimic EPC-MPs group was complete,the size of some mitochondria was in-creased,the surface of the endoplasmic reticulum had fewer ribosomes,and some of the Golgi vesicles gath-ered.Compared with the OGD/R+EPC-MPs group,the expression levels of IL-6,TNF-α and HMGB-1 in the OGD/R+miR-126 mimic EPC-MPs group were down-regulated.Compared with the OGD/R+EPC-MPs group,the expression levels of Ang Ⅱ,caspase-6,p-ERK1/2 and GRP78 protein in the OGD/R+miR-126 mimic EPC-MPs group were down-regulated,and the expression levels of p-LKB1,GM130 and PGC-1α protein in the OGD/R+miR-126 mimic EPC-MPs group were up-regulated.The quantitative PCR(qPCR) results showed that compared with the OGD/R+EPC-MPs group,the expression levels of Ang Ⅱ,MPO and GRP78 in the OGD/R+miR-126 mimic EPC-MPs group were down-regulated,and the expression levels of eNOS,GM130 and PGC-1α were up-regulated.Conclusion When OGD/R injury occurs in cardiomyocytes,miR-126 mimic EPC-MPs regulates PGC-1α/GM130 expression and inhibits Ang Ⅱ-induced stress injury response,thereby reduces the OGD/R damage in cardiomyocytes.

Objective To study the diagnostic value of miR-126 and ICAM-1 in peripheral blood endo-thelial microparticles(EMPs)of the patients with acute myocardial infarction(AMI).Methods A total of 45 patients with definitely diagnosed AMI in this hospital from September 2021 to June 2022 were selected as the AMI group.Other 45 healthy subjects in the same age group and sex were selected as the control group.Be-fore coronary angiography,the patient's peripheral blood was collected,and the flow cytometry was used to conduct the qualitative and quantitative analysis on EMPs.The expression levels of miR-126 and ICAM-1 in EMPs were determined by using fluorogenic quantitative PCR and ELISA.The receiver operating characteristic(ROC)curve was adopted to evaluate the diagnostic value of the related indicators for AMI.Results There was no statistically significant difference in the general data such as age,gender and BMI between the two groups(P＞0.05).The biochemical indicators such as PLT,BUN,TC,TG and HDL-C had no statistical difference between the two groups(P＞0.05).The expression level of miR-126 in the AMI group was significantly lower than that in the control group,the expression level of ICAM-1 in the AMI group was higher than that in the control group,and the differences were not statistically significant(P＜0.05).The miR-126 expression level in the AMI group was lower than that in the control group,the ICAM expression level was higher than that in the control group,and the differences were statistically significant(P＜0.05).The multivariate logistic regression results showed that miR-126,ICAM-1 and CK-MB had the independent correlation with the AMI occurrence(P＜0.05).The area under the curve(AUC)of mir-126 for diagnosing AMI was 0.813(95％CI:0.725-0.903,P＜0.001),which of ICAM-1 was 0.848(95％CI:0.764-0.933,P＜0.001),and which of miR-126 and ICAM-1 combination diagnosis was 0.922(95％CI:0.870-0.946,P＜0.001).Conclusion The miR-126 and ICAM-1 expression levels in EMPs have the independent correlation with AMI,and the both have the di-agnostic value for AMI.