van der Zee P Marc, Biró Eva, Ko Yung, de Winter Robbert J, Hack C Erik, Sturk Augueste, Nieuwland Rienk
Department of Cardiology and Laboratory of Experimental Clinical Chemistry, Academic Medical Center of the University of Amsterdam, Amsterdam, The Netherlands.
Clin Chem. 2006 Apr;52(4):657-64. doi: 10.1373/clinchem.2005.057414. Epub 2006 Jan 26.
Platelet-derived microparticles (PMPs) are generally considered a marker of platelet activation in cardiovascular disease. We studied the extent to which PMP subpopulations parallel platelet activation in vitro and in vivo.
Using flow cytometry, we analyzed PMP subpopulations from resting and activated platelets in vitro (n = 6) as well as from plasma samples of patients with stable angina, peripheral arterial disease, or myocardial infarction [non-ST-elevation (NSTEMI) and ST-elevation (STEMI)] and from older, age- and sex-matched and young healthy individuals [n = 10 for all groups except NSTEMI (n = 11)]. Coagulation markers prothrombin fragment F(1 + 2) and thrombin-antithrombin complexes were determined by ELISA. The PMP-associated fraction of soluble (s)P-selectin was estimated by ELISA.
In vitro, stimulation of platelets with thrombin receptor-activating peptide (15 micromol/L) or the calcium ionophore A23187 (2.5 micromol/L) increased fractions of both platelets and PMPs exposing P-selectin or CD63 (P <0.001 for all). Whereas the number of PMPs released by A23187-stimulated platelets increased significantly (P <0.001), the number of PMPs released from thrombin receptor-activating peptide-stimulated platelets remained constant (P >0.05). Ex vivo, numbers of circulating PMPs were comparable in all groups. Compared with young persons, P-selectin-exposing PMPs were increased in older persons (P = 0.02) and were further increased in patients with NSTEMI (P = 0.007) and STEMI (P = 0.045). CD63-exposing PMPs were increased in patients with peripheral arterial disease (P = 0.041), NSTEMI (P = 0.001), and STEMI (P = 0.049). Subpopulations exposing P-selectin or CD63 correlated with each other (r = 0.581; P <0.001), but neither correlated with the plasma concentrations of F(1 + 2) or thrombin-antithrombin complexes. The PMP-associated fraction of sP-selectin constituted only 2.2 (4.7)% [mean (SD)] of total sP-selectin.
PMP subpopulations reflect platelet activation status better than the total number of PMPs. Increased concentrations of circulating PMP subpopulations are found in aging, and further increases are encountered in peripheral arterial disease and myocardial infarction.
血小板衍生微粒（PMPs）通常被认为是心血管疾病中血小板活化的标志物。我们研究了PMP亚群在体外和体内与血小板活化平行的程度。
使用流式细胞术，我们分析了体外（n = 6）静息和活化血小板的PMP亚群，以及稳定型心绞痛、外周动脉疾病或心肌梗死[非ST段抬高（NSTEMI）和ST段抬高（STEMI）]患者的血浆样本，以及年龄、性别匹配的老年人和年轻健康个体的血浆样本[除NSTEMI组（n = 11）外，所有组均为n = 10]。通过ELISA测定凝血标志物凝血酶原片段F(1 + 2)和凝血酶 - 抗凝血酶复合物。通过ELISA估计可溶性（s）P - 选择素的PMP相关部分。
在体外，用凝血酶受体激活肽（15 μmol/L）或钙离子载体A23187（2.5 μmol/L）刺激血小板会增加暴露P - 选择素或CD63的血小板和PMP的比例（所有P <0.001）。虽然A23187刺激的血小板释放的PMP数量显著增加（P <0.001），但凝血酶受体激活肽刺激的血小板释放的PMP数量保持不变（P >0.05）。在体外，所有组中循环PMP的数量相当。与年轻人相比，暴露P - 选择素的PMP在老年人中增加（P = 0.02），在NSTEMI患者（P = 0.007）和STEMI患者（P = 0.045）中进一步增加。暴露CD63的PMP在周围动脉疾病患者（P = 0.041）、NSTEMI患者（P = 0.001）和STEMI患者（P = 0.049）中增加。暴露P - 选择素或CD63的亚群相互相关（r = 0.581；P <0.001），但两者均与F(1 + 2)或凝血酶 - 抗凝血酶复合物的血浆浓度无关。sP - 选择素的PMP相关部分仅占总sP - 选择素的2.2（4.）%[平均值（标准差）]。
PMP亚群比PMP总数更能反映血小板活化状态。在衰老过程中发现循环PMP亚群浓度增加，在外周动脉疾病和心肌梗死中进一步增加。
