BACKGROUND Prediction of thrombus formation at intact arterial walls under low shear flow conditions is clinically important particularly for better prognoses of embolisation in cerebral aneurysms. Although a new mathematical model for this purpose is necessary, little quantitative information has been known about platelet adhesion to intact endothelial cells. OBJECTIVE The objective of this study is to measure the number of platelets adhering to intact endothelial cells with a focus upon the influence of the shear rate. METHODS Endothelial cells disseminated in μ-slides were exposed to swine whole blood at different shear rates. Adenosine diphosphate (ADP) was used as an agonist. Adherent platelets were counted by means of scanning electron microscopy. RESULTS At an ADP concentration of 1 µM, 20.8 ± 3.1 platelets per 900 µm2 were observed after 30-minute perfusion at a shear rate of 0.8 s-1 whereas only 3.0 ± 1.4 per 900 µm2 at 16.8 s-1. CONCLUSIONS The number of adherent platelets is determined by a balance between the shear and the degree of stimulation by the agonist. At an ADP concentration of 1 µM, a limit to the shear rate at which platelets can adhere to intact endothelial cells is considered to be slightly higher than 16.8 s-1.

中文翻译：

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低剪切条件下血小板对完整内皮细胞粘附的体外测量。

背景技术在低剪切流动条件下完整动脉壁处血栓形成的预测在临床上尤其重要，特别是对于脑动脉瘤中栓塞的更好预后。尽管为此目的需要一个新的数学模型，但关于血小板粘附至完整内皮细胞的定量信息知之甚少。目的本研究的目的是测量粘附在完整内皮细胞上的血小板数量，重点是剪切速率的影响。方法以μ-slide分散的内皮细胞以不同的剪切速率暴露于猪全血。二磷酸腺苷（ADP）用作激动剂。通过扫描电子显微镜对粘附的血小板计数。结果在ADP浓度为1 µM，20.8±3的情况下。在以0.8 s-1的剪切速率灌注30分钟后，每900 µm2观察到1个血小板，而在16.8 s-1时，每900 µm2仅观察到3.0±1.4个血小板。结论粘附血小板的数量取决于剪切力和激动剂刺激程度之间的平衡。在ADP浓度为1 µM时，血小板可以粘附至完整内皮细胞的剪切速率极限被认为略高于16.8 s-1。