Smith N M, Pathansali R, Bath P M
Department of Medicine, King's College School of Medicine and Dentistry, London, UK.
Vasc Med. 1999;4(3):165-72. doi: 10.1177/1358836X9900400307.
Platelets are anucleate cells with little or no capacity for de novo protein synthesis. Their potential haemostatic reactivity is established at or before thrombopoiesis by their precursor cell, the bone marrow megakaryocyte. In some pathologic conditions, the megakaryocyte-platelet-haemostatic axis (MPHA) becomes perturbed, resulting in the formation of hyperfunctional platelets which may contribute to the development of vascular disease or an acute thrombotic event such as ischaemic stroke or myocardial infarction. Laboratory measurements of platelet function have established that platelet reactivity is accentuated in acute ischaemic stroke, particularly following cortical rather than lacunar infarction. Whether accentuated platelet function is a cause or a consequence of stroke is not yet clear, but it is likely that patients with certain risk factor profiles have some degree of platelet activation preceding the stroke. Further work into the MPHA is required to establish whether enhanced post-stroke platelet reactivity can be referred to the megakaryocyte. The antiplatelet agents tested to date are effective in secondary but not primary prevention of stroke. This probably reflects the diverse pathophysiology of stroke: accentuated platelet function is only likely to be a significant factor in cortical stroke.
血小板是无核细胞，几乎没有或完全没有从头合成蛋白质的能力。它们潜在的止血反应性在血小板生成过程中或之前由其前体细胞——骨髓巨核细胞确立。在某些病理状况下，巨核细胞-血小板-止血轴（MPHA）会受到干扰，导致形成功能亢进的血小板，这可能会促成血管疾病的发展或引发急性血栓事件，如缺血性中风或心肌梗死。实验室对血小板功能的测量已证实，急性缺血性中风时血小板反应性会增强，尤其是在皮质梗死而非腔隙性梗死之后。血小板功能增强是中风的原因还是后果尚不清楚，但很可能具有某些风险因素特征的患者在中风前就存在一定程度的血小板激活。需要对MPHA进行进一步研究，以确定中风后血小板反应性增强是否可归因于巨核细胞。迄今为止所测试的抗血小板药物在中风的二级预防中有效，但在一级预防中无效。这可能反映了中风多样的病理生理学：血小板功能增强仅可能是皮质中风的一个重要因素。
