Abstract: Background Acute myocardial infarction（AMI）is the leading cause of cardiovascular disease morbidity and mortality worldwide，and despite the widespread use of biomarkers for myocardial necrosis，morbidity and mortality of AMI remain high. Objective To investigate the expression levels and clinical significance of miR-126，mitochondrial components and adhesion molecules in endothelial microparticles（EMPs）. Methods A total of 50 patients with AMI，50 patients with stable coronary artery disease（SCAD）and 50 healthy subjects were enrolled in the People's Hospital of Xinjiang Uygur Autonomous Region from September 2021 to September 2022. AMI patients and SCAD patients were hospitalized in our hospital and received percutaneous coronary intervention（PCI），and all healthy subjects were evaluated by the physical examination center of our hospital. Peripheral blood samples and general data of three groups were collected. The morphology of the microparticles（MPs） was observed by transmission electron microscopy（TEM），the level of EMPs was identified by flow cytometry，and the expression of miR-126 in EMPs was detected by fluorescence quantitative PCR. ELISA was used to detect the levels of mitochondrial reactive oxygen species（ROS）and intracellular adhesion molecules ［vascular cell adhesion molecule-1 （VCAM-1），intercellular adhesion molecule-1（ICAM-1），E-selectin，and P-selectin］ in EMPs. Results As observed by TEM，the membrane structure of the isolated MPs was intact and its diameter ranged from 100 to 400 nm. Compared with the control group，the expression of miR-126 in plasma EMPs in the AMI group was significantly decreased（Z=4.979， P<0.001），the expression of ROS was significantly increased（Z=9.651，P<0.001），the expression of VCAM-1 was increased（Z=2.336，P=0.019），and the expression of ICAM-1（Z=5.894，P<0.001），E-selectin（Z=2.730，P=0.019） and P-selectin（Z=6.470，P<0.001） were increased. Multivariate Logistic regression analysis showed that the decreased expression of miR-126（OR=0.026，95%CI=0.003-0.210，P=0.001） was a protective factor for AMI，increased expression of ROS（OR=1.009，95%CI=1.005-1.013，P<0.001） and P-selectin（OR=1.063，95%CI=1.022-1.105，P=0.002）were risk factors for AMI. The receiver operator characteristic curve（ROC） showed that the area under the curve of miR-126 for the diagnosis of AMI was 0.816，the area under the curve of ROS for the diagnosis of AMI was 0.892，the area under the curve of P-selectin for the diagnosis of AMI was 0.728，and the area under the curve of miR-126，ROS and P-selectin combined diagnosis was 0.950. Conclusion In EMPs，miR-126，ROS，P-selectin and their combined indicators all have diagnostic value for AMI，and the combined indicators of the three have the highest diagnostic value，indicating that they may be potential diagnostic indicators for AMI patients.

Key words: Acute myocardial infarction, Endothelial cell, Microparticles, miR-126, Mitochondria, Adhesion molecules, Clinical significance

摘要： 背景　急性心肌梗死（AMI）是全世界心血管疾病发病率和死亡率的主要原因，尽管目前心肌坏死的生物标志物被广泛应用，但 AMI 的发病率和死亡率仍然居高不下。目的　拟研究内皮细胞微粒（EMPs）内含 miR-126、线粒体成分、黏附分子的表达水平及临床意义。方法　纳入 2021 年 9 月—2022 年 9 月于新疆维吾尔自治区人民医院就诊的 AMI 患者 50 例、稳定性冠心病（SCAD）患者 50 例、健康者 50 例，AMI 患者和 SCAD 患者均在本院住院并接受冠状动脉介入治疗（PCI），健康者均经过本院体检中心的评估。收集三组外周血标本及一般资料，利用透射电镜观察微粒的形态，流式细胞术鉴定 EMPs 水平，荧光定量 PCR 检测 EMPs 中 miR-126 的表达，ELISA 检测 EMPs 中线粒体活性氧（ROS）及内含黏附分子［血管细胞黏附分子 1（VCAM-1）、细胞间黏附分子 1（ICAM-1）、E- 选择素、P- 选择素］的水平。结果　通过透射电镜观察到，分离的 MPs 膜结构完整，直径在 100~400 nm。与 Control 组相比，AMI组血浆 EMPs 中 miR-126 表达水平下降（Z=4.979，P<0.001），ROS 表达水平升高（Z=9.651，P<0.001），VCAM-1表达水平升高（Z=2.336，P=0.019），ICAM-1 表达水平升高（Z=5.894，P<0.001），E- 选择素表达水平升高（Z=2.730，P=0.019），P- 选择素表达水平升高（Z=6.470，P<0.001）。多因素 Logistic 回归分析结果显示，miR-126 表达水平降低（OR=0.026，95%CI=0.003-0.210，P=0.001）是 AMI 的保护因素，ROS（OR=1.009，95%CI=1.005-1.013，P<0.001）、P- 选择素表达水平升高（OR=1.063，95%CI=1.022-1.105，P=0.002）是 AMI 的危险因素。受试者工作特征曲线（ROC）显示，miR-126 诊断 AMI 的曲线下面积为 0.816，ROS 诊断 AMI 的曲线下面积为 0.892，P- 选择素诊断 AMI 的曲线下面积为0.728，miR-126、ROS、P- 选择素联合诊断的曲线下面积为 0.950。结论　EMPs 中 miR-126、ROS、P- 选择素以及三者联合指标均对 AMI 有诊断价值，并且三者联合指标诊断价值最高，这表明其可能为 AMI 患者的潜在诊断指标。

关键词: 急性心肌梗死, 内皮细胞, 微粒, miR-126, 线粒体, 黏附分子, 临床意义