Application Of Flow Cytometry In Estimation Of Microparticles And Its Clinical Significance

Objective:To establish the method for detecting circulating microparticles(MPs) by flow cytometry and investigate whether anticoagulant and storage can influence them. Another purpose of this study was to access the possible relationship between MPs and clinical subgroups of coronary artery disease(CAD).Method:We studied 36 patients with CAD,including 12 with myocardial infarction(MI), 12 with unstable angina(UA),12 with stable angina,and 12 control subjects.Three vacuum tubes were collected on sodium citrate,EDTA-K2 and non-anticoagulant by puncture of a forearm vein in 12 controls.Endothelial microparticles(EMPs,defined as CD31+/CD42-) and Platelet microparticles(PMPs,defined as CD31+/CD42+) were counted by flow cytometry in 1 hour,or after storage for 4 hours at room temperature or 24 hours at 4℃.Two types of MPs were also counted in platelet-poor plasma (anticoagulated by sodium citrate) of 36 patients.Results:The level of EMPs and PMPs of sodium citrate plasma in 1 hour was 57.4±57.7/μL and 1092.4±883.1/μL,compared with storage for 4 hours(53.9±52.6/μL,1049.0±831.9/μL,24 hours(45.7±38.3/μL,739.7±604.5/μL),P＝0.103,0.082 and 0.091,0.006. A simultaneous assay of EMPs and PMPs of EDTA-K2 plasma in 4 hour was. 7.6±6.6/μL and 137.4±115.5/μL,compared with sodium citrate plasma,P＝0.007,0.002. EMPs were significantly higher in patients with acute coronary syndromes(ACS), including MI and UA,than in SA and controls(P＜0.05).But the same result was not found in SA and controls.The counts of EMPs in three subgroups of CAD were MI＞UA＞SA.However,PMPs did not discriminate patients with MI from UA,and UA from SA.Conelutions:Sodium citrate was a suitable anticoagulant to evaluate MPs by flow.cytometry, and the analysis should be completed in 4 hours.MPs may be a useful marker in detecting endothelial dysfunction and coagulating function in ACS.Monitoring the level of plasma EMPs could estimate the progress of angina pectoris.