Supraphysiological shear rates (>2000 s−1) amplify von Willebrand factor unfurling and increase platelet activation and adhesion. These elevated shear rates and shear rate gradients also play a role in shear-induced platelet aggregation (SIPA). The primary objective of this study is to investigate the contributions of major binding receptors to platelet deposition and SIPA in a stenotic model. Microfluidic channels with stenotic contractions ranging from 0% to 75% are fabricated and coated with human type I collagen at 100 μg/mL. Fresh human blood is reconstituted to 40% hematocrit and treated to stain platelets. Platelet receptors αIIbβ3, GPIb, or GPVI are blocked with inhibitory antibodies or proteins to reduce platelet function under flow at 500, 1000, 5000, or 10,000 s−1 over 5 min of perfusion. Additional validation experiments are performed by dual-blocking receptors and performing coagulability testing by rotational thromboelastometry. Control samples exhibit SIPA correlating to increasing shear rate and increasing stenotic contraction. Inhibition of αIIbβ3 or GPIb receptors causes a nearly total reduction in platelet adhesion and a loss of aggregation at >1000 s−1. GPVI inhibition does not notably reduce platelet adhesion at 500 or 1000 s−1 but affects microthrombus stability at 5000–10,000 s−1 following aggregation formation in 50%–75% stenotic channels. Inhibition of von Willebrand factor-binding receptors completely blocks adhesion and aggregation at shear rates >1000 s−1. Inhibition of GPVI reduces platelet adhesion at 5000–10,000 s−1 but renders thrombi susceptible to fragmentation. This study yields further insight into mechanisms regulating rapid growth and stabilization of arterial thrombi at supraphysiological shear rates.

中文翻译：

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GPVI 介导的微流体狭窄中剪切诱导血小板聚集体的血栓稳定


超生理剪切速率 （>2000 s−1） 放大血管性血友病因子展开并增加血小板活化和粘附。这些升高的剪切速率和剪切速率梯度也在剪切诱导血小板聚集 （SIPA） 中发挥作用。本研究的主要目的是研究狭窄模型中主要结合受体对血小板沉积和 SIPA 的贡献。制造狭窄收缩范围为 0% 至 75% 的微流体通道，并用 100 μg/mL 的人 I 型胶原蛋白包被。新鲜人血复溶成 40% 血细胞比容，并处理血小板染色。血小板受体 αIIbβ3、GPIb 或 GPVI 在灌注 5 分钟内，在 500、1000、5000 或 10,000 s-1 的流速下被抑制性抗体或蛋白质阻断，以降低血小板功能。通过双重阻断受体进行额外的验证实验，并通过旋转血栓弹力测定法进行凝血能力测试。对照样品显示 SIPA 与剪切速率增加和狭窄收缩增加相关。αIIbβ3 或 GPIb 受体的抑制导致血小板粘附几乎完全减少，并在 >1000 s-1 处聚集丧失。GPVI 抑制在 500 或 1000 s-1 时不会显着降低血小板粘附，但在 50%-75% 狭窄通道中聚集形成后，会影响 5000-10,000 s-1 时的微血栓稳定性。抑制血管性血友病因子结合受体在剪切速率 >1000 s-1 下完全阻断粘附和聚集。抑制 GPVI 可降低 5000-10,000 s-1 处的血小板粘附，但使血栓易碎裂。这项研究进一步揭示了在超生理剪切速率下调节动脉血栓快速生长和稳定的机制。