Abstract 14015: Circulating CD31+/CD42- Endothelial Microparticles Reflect the Size of Myocardium at Risk in Patients With ST-Elevation Myocardial Infarction
Objectives: Endothelial microparticles (EMP) are small membrane vesicles, released from activated, damaged and apoptotic endothelial cells. EMP can be characterized by the presence of endothelial-specific surface antigens. They do not only reflect ongoing damage or activation of endothelium but also actively modulate processes in inflammation, coagulation and vascular function. In the present study we tested the hypothesis that an elevated number of circulating EMP in acute myocardial infarction correlates with the myocardium at risk (MaR) and infarct size (IS).
Methods: EMPs were quantified in plasma samples of 36 patients (30 male, age: 63 ± 10 years, BMI: 26.6 ± 2.8 kg/m2) with first time ST-elevation myocardial infarction (STEMI) using flow cytometry. The blood sample was collected between 48–72h after admission. EMPs were defined as CD31+/CD42- MP, and CD144+ MP. MaR and IS was determined by cardiovascular magnetic resonance one week after the index event. Blood samples for troponin T were collected every 4 h for 24 h and every 6 h for an additional 24 h.
Results: Plasma levels of CD31+/CD42- EMP were 251.0 ± 178.8 per μl and CD144+ 106.3 ± 33.7 per μl. MaR was 31.0 ± 11.2% of the left ventricle and IS was 11.4 ± 7.1% of the left ventricle. Patients with STEMI in the left anterior descending artery had higher levels of CD31+/CD42- EMP than those with other infarct-related arteries (p<0.05). The numbers of CD31+/CD42- EMP correlated to MaR (Spearman, p=0.004, r=0.48), but not to IS (Spearman, p=0.06, r=0.32). CD144+ EMP did not correlate significantly to MaR or IS. CD31+/CD42- EMP correlated to the area under the curve of troponin T levels (Spearman, p=0.005, r=0.48).
Conclusions: Circulating EMP correlate to the size of MaR in patients with STEMI suggesting that they reflect the severity of the endothelial injury and myocardial ischemia. The present findings support the view that CD31+/CD42- is the more sensitive marker of EMP release triggered by ischemia.
- © 2010 by American Heart Association, Inc.