Sakariassen K S, Holme P A, Orvim U, Barstad R M, Solum N O, Brosstad F R
Bioreg Research, Nycomed Imaging AS, Oslo, Norway.
Thromb Res. 1998 Dec 15;92(6 Suppl 2):S33-41. doi: 10.1016/s0049-3848(98)00158-3.
Shear-induced platelet activation and platelet microparticle formation are triggered in native human blood by high arterial shear or by a sudden increase in shear as introduced by a stenosis with potential consequences for collagen-induced platelet thrombus formation. Blood was drawn from healthy volunteers and directly perfused ex vivo over various well-defined eccentric stenoses. Shear-induced platelet activation was determined by using flow cytometry to assess: 1) GPIIb-IIIa activation by fluorescein isothiocyanate (FITC)-labeled Mab PAC-1; and 2) translocation of membrane aminophospholipids (procoagulant activity) by FITC-labeled Annexin V. Microparticle formation was measured by flow cytometry and FITC-labeled Mab Y2/51 directed against GPIIIa. Significant platelet activation and platelet microparticle formation were elicited when the wall shear rate reached 10,500 sec-1 for a period of 0.075 sec. Prolonged exposure to or a rapid increase in shear further enhanced activation and microparticle formation. Shear-induced platelet activation was associated with significantly increased collagen-induced platelet thrombus formation that was insensitive to aspirin ingestion. Exposure of native blood to very high shear thus activates platelets to express GPIIb-IIIa, renders the platelet membrane procoagulant and stimulates microparticle formation. These responses are associated with enhanced collagen-induced thrombus formation by prostaglandin-independent mechanisms.
在天然人血液中，高动脉剪切力或由狭窄引起的剪切力突然增加会引发剪切诱导的血小板活化和血小板微粒形成，这可能对胶原蛋白诱导的血小板血栓形成产生影响。从健康志愿者身上抽取血液，并在体外直接灌注到各种明确的偏心狭窄处。通过流式细胞术测定剪切诱导的血小板活化，以评估：1）异硫氰酸荧光素（FITC）标记的单克隆抗体PAC-1对糖蛋白IIb-IIIa的活化；2）FITC标记的膜联蛋白V对膜氨基磷脂的易位（促凝血活性）。通过流式细胞术和针对糖蛋白IIIa的FITC标记单克隆抗体Y2/51测量微粒形成。当壁面剪切速率达到每秒10,500时持续0.075秒，会引发显著的血小板活化和血小板微粒形成。长时间暴露于剪切力或剪切力快速增加会进一步增强活化和微粒形成。剪切诱导的血小板活化与胶原蛋白诱导的血小板血栓形成显著增加相关，且对阿司匹林摄入不敏感。因此，将天然血液暴露于非常高的剪切力会激活血小板以表达糖蛋白IIb-IIIa，使血小板膜具有促凝血性并刺激微粒形成。这些反应通过不依赖前列腺素的机制与增强的胶原蛋白诱导的血栓形成相关。
