Watson Connor T, Siedlecki Christopher A, Manning Keefe B
Department of Biomedical Engineering, The Pennsylvania State University, University Park, Pennsylvania.
Department of Biomedical Engineering, The Pennsylvania State University, University Park, Pennsylvania; Department of Surgery, Penn State College of Medicine, Hershey, Pennsylvania.
Biophys J. 2025 Jan 7;124(1):158-171. doi: 10.1016/j.bpj.2024.11.018. Epub 2024 Nov 22.
Supraphysiological shear rates (>2000 s) 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 αβ, GPIb, or GPVI are blocked with inhibitory antibodies or proteins to reduce platelet function under flow at 500, 1000, 5000, or 10,000 s 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 αβ or GPIb receptors causes a nearly total reduction in platelet adhesion and a loss of aggregation at >1000 s. GPVI inhibition does not notably reduce platelet adhesion at 500 or 1000 s but affects microthrombus stability at 5000-10,000 s 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. Inhibition of GPVI reduces platelet adhesion at 5000-10,000 s 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.
超生理剪切速率(>2000 s⁻¹)会放大血管性血友病因子的展开,并增加血小板的活化和黏附。这些升高的剪切速率和剪切速率梯度在剪切诱导的血小板聚集(SIPA)中也起作用。本研究的主要目的是在狭窄模型中研究主要结合受体对血小板沉积和SIPA的作用。制备了狭窄收缩范围为0%至75%的微流体通道,并用100 μg/mL的人I型胶原蛋白包被。将新鲜人血重悬至血细胞比容为40%,并进行处理以标记血小板。在5分钟的灌注过程中,用抑制性抗体或蛋白质阻断血小板受体αβ、糖蛋白Ib(GPIb)或糖蛋白VI(GPVI),以降低流动状态下的血小板功能,剪切速率分别为500、1000、5000或10000 s⁻¹。通过双重阻断受体并采用旋转血栓弹力图进行凝血能力测试来进行额外的验证实验。对照样品显示SIPA与增加的剪切速率和增加的狭窄收缩相关。抑制αβ或GPIb受体可导致血小板黏附几乎完全减少,并且在>1000 s⁻¹时聚集丧失。抑制GPVI在500或1000 s⁻¹时不会显著降低血小板黏附,但在50%-75%狭窄通道中聚集形成后,在5000-10000 s⁻¹时会影响微血栓稳定性。抑制血管性血友病因子结合受体在剪切速率>1000 s⁻¹时完全阻断黏附和聚集。抑制GPVI在5000-10000 s⁻¹时降低血小板黏附,但使血栓易于破碎。本研究进一步深入了解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。