Roka-Moiia Yana, Ammann Kaitlyn, Miller-Gutierrez Samuel, Sheriff Jawaad, Bluestein Danny, Italiano Joseph E, Flaumenhaft Robert C, Slepian Marvin J
bioRxiv. 2023 Feb 8:2023.02.08.527675. doi: 10.1101/2023.02.08.527675.
Implantable cardiovascular therapeutic devices (CTD) including stents, percutaneous heart valves and ventricular assist devices, while lifesaving, impart supraphysiologic shear stress to platelets resulting in thrombotic and bleeding device-related coagulopathy. We previously demonstrated that shear-mediated platelet dysfunction is associated with downregulation of platelet GPIb-IX-V and αIIbβ3 receptors via generation of platelet-derived microparticles (PDMPs). Here, we test the hypothesis that shear-generated PDMPs manifest phenotypical heterogeneity of their morphology and surface expression of platelet receptors, and modulate platelet hemostatic function.
Human gel-filtered platelets were exposed to continuous shear stress and sonication. Alterations of platelet morphology were visualized using transmission electron microscopy. Surface expression of platelet receptors and PDMP generation were quantified by flow cytometry. Thrombin generation was quantified spectrophotometrically, and platelet aggregation in plasma was measured by optical aggregometry. We demonstrate that platelet exposure to shear stress promotes notable alterations in platelet morphology and ejection of several distinctive types of PDMPs. Shear-mediated microvesiculation is associated with the differential remodeling of platelet receptors with PDMPs expressing significantly higher levels of both adhesion (α β , GPIX, PECAM-1, P-selectin, and PSGL-1) and agonist-evoked receptors (P Y & PAR1). Shear-mediated PDMPs have a bidirectional effect on platelet hemostatic function, promoting thrombin generation and inhibiting platelet aggregation induced by collagen and ADP.
Shear-generated PDMPs demonstrate phenotypic heterogeneity as to morphologic features and defined patterns of surface receptor alteration, and impose a bidirectional effect on platelet hemostatic function. PDMP heterogeneity suggests that a range of mechanisms are operative in the microvesiculation process, contributing to CTD coagulopathy and posing opportunities for therapeutic manipulation.
可植入式心血管治疗设备（CTD），包括支架、经皮心脏瓣膜和心室辅助装置，虽然能挽救生命，但会给血小板施加超生理剪切应力，导致血栓形成和与装置相关的出血性凝血病。我们之前证明，剪切介导的血小板功能障碍与血小板衍生微粒（PDMP）生成导致的血小板糖蛋白Ib-IX-V和αIIbβ3受体下调有关。在此，我们检验以下假设：剪切产生的PDMP在其形态和血小板受体的表面表达上表现出表型异质性，并调节血小板止血功能。
将人凝胶过滤血小板暴露于持续剪切应力和超声处理下。使用透射电子显微镜观察血小板形态的改变。通过流式细胞术对血小板受体的表面表达和PDMP生成进行定量。用分光光度法定量凝血酶生成，并用光学聚集法测量血浆中的血小板聚集。我们证明，血小板暴露于剪切应力会促进血小板形态的显著改变以及几种不同类型PDMP的释放。剪切介导的微囊化与血小板受体的差异重塑有关，PDMP表达的粘附受体（αIIbβ3、GPIX、PECAM-1、P-选择素和PSGL-1）和激动剂诱导受体（P2Y1&PAR1）水平均显著更高。剪切介导的PDMP对血小板止血功能有双向作用，促进凝血酶生成并抑制胶原蛋白和ADP诱导的血小板聚集。
剪切产生的PDMP在形态特征和表面受体改变的特定模式方面表现出表型异质性，并对血小板止血功能产生双向作用。PDMP异质性表明在微囊化过程中有一系列机制起作用，这导致了CTD凝血病，并为治疗干预提供了机会。
