Ultrastructural studies of platelet aggregates from human subjects receiving clopidogrel and from a patient with an inherited defect of an ADP-dependent pathway of platelet activation.
Ultrastructural studies of platelet aggregates from human subjects receiving clopidogrel and from a patient with an inherited defect of an ADP-dependent pathway of platelet activation.
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对接受氯吡格雷的人类受试者和患有 ADP 依赖性血小板活化途径遗传缺陷的患者的血小板聚集体进行超微结构研究。
DOI：
10.1161/01.atv.16.12.1532
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Nurden,AT
中科院分区：
文献类型：
--
作者：
Humbert,M;Nurden,P;Bihour,C;Pasquet,JM;Winckler,J;Heilmann,E;Savi,P;Herbert,JM;Kunicki,TJ;Nurden,AT
我们的研究探讨了抗血栓药物氯吡格雷（75 mg/d，7天）对ADP或2-甲硫基-ADP（2-MeS-ADP）诱导的富血小板血浆中血小板聚集体的超微结构的影响，并检查了GP IIb/IIIa复合物的活化状态。将结果与患者M.L.的结果进行比较，患有一种先天性疾病，其特征是血小板对ADP的反应降低且可逆。当未经处理的正常血小板与高剂量ADP刺激，电子显微镜显示大而稳定的聚集体往往包围着一层什么似乎是脱颗粒血小板。接受氯吡格雷的受试者或患者M.L.没有显示这一层。电子显微镜显示，在这两种情况下，聚集体由松散结合的血小板组成，接触点很少。ADP或2-MeS-ADP形成的Lowicryl包埋聚集体的切片的免疫金标记显示，（1）多克隆抗纤维蛋白原抗体和（2）AP-6（一种对纤维蛋白原占据的GP IIb/IIIa复合物具有特异性的鼠抗配体诱导的结合位点单克隆抗体）的血小板表面染色显著降低。在解聚后观察到类似的结果，此时存在许多没有分泌迹象的单个血小板。流式细胞术证实，氯吡格雷治疗后，ADP或2-MeS-ADP刺激的血小板上配体占据的GP IIb/IIIa复合物的数量要低得多。正如先前研究所预期的，ADP诱导的血小板形状改变和Ca 2+内流不受氯吡格雷的影响。这些结果与ADP激活血小板是双相的假设一致，并强调了受氯吡格雷影响的受体诱导的激活途径（或患者M.L.的先天性受损）。这对于GP IIb/IIIa的完全活化和稳定的大聚集体的形成是必需的。
Our study investigated the effect of the antithrombotic drug clopidogrel (75 mg/d for 7 days) on the ultrastructure of platelet aggregates induced by ADP or 2-methylthio-ADP (2-MeS-ADP) in citrated platelet-rich plasma and examined the activation state of the GP IIb/IIIa complexes. Results were compared with those obtained for patient M.L., who has a congenital disorder characterized by a reduced and reversible platelet response to ADP. When untreated normal platelets were stimulated with high-dose ADP, electron microscopy revealed large and stable aggregates often surrounded by a layer of what appeared to be degranulated platelets. The reversible aggregates of platelets from subjects receiving clopidogrel or from patient M.L. did not show this layer. Electron microscopy showed that in both situations, the aggregates were composed of loosely bound platelets with few contact points. Immunogold labeling of ultrathin sections of Lowicryl-embedded aggregates formed by ADP or 2-MeS-ADP showed a much decreased platelet surface staining by (1) a polyclonal anti-fibrinogen antibody and (2) AP-6, a murine anti–ligand-induced binding site monoclonal antibody specific for GP IIb/IIIa complexes occupied with fibrinogen. Similar findings were seen after disaggregation, when many single platelets were present that showed no signs of secretion. Flow cytometry confirmed that the number of ligand-occupied GP IIb/IIIa complexes was much lower on platelets stimulated with ADP or 2-MeS-ADP after clopidogrel treatment. As expected from previous studies, ADP-induced platelet shape change and Ca2+influx were unaffected by clopidogrel. These results agree with the hypothesis that platelet activation by ADP is biphasic and highlight a receptor-induced activation pathway affected by clopidogrel (or congenitally impaired in patient M.L.) that is necessary for the full activation of GP IIb/IIIa and the formation of stable macroaggregates.