Welsh J D, Poventud-Fuentes I, Sampietro S, Diamond S L, Stalker T J, Brass L F
Departments of Medicine and Pharmacology, University of Pennsylvania, Philadelphia, PA, USA.
Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA.
J Thromb Haemost. 2017 Mar;15(3):526-537. doi: 10.1111/jth.13600. Epub 2017 Feb 6.
Essentials Methods were developed to image the hemostatic response in mouse femoral arteries in real time. Penetrating injuries produced thrombi consisting primarily of platelets. Similar to arterioles, a core-shell architecture of platelet activation occurs in the femoral artery. Differences from arterioles included slower platelet activation and reduced thrombin dependence.
Background Intravital studies performed in the mouse microcirculation show that hemostatic thrombi formed after penetrating injuries develop a characteristic architecture in which a core of fully activated, densely packed platelets is overlaid with a shell of less activated platelets. Objective Large differences in hemodynamics and vessel wall biology distinguish arteries from arterioles. Here we asked whether these differences affect the hemostatic response and alter the impact of anticoagulants and antiplatelet agents. Methods Approaches previously developed for intravital imaging in the mouse microcirculation were adapted to the femoral artery, enabling real-time fluorescence imaging despite the markedly thicker vessel wall. Results Arterial thrombi initiated by penetrating injuries developed the core-and-shell architecture previously observed in the microcirculation. However, although platelet accumulation was greater in arterial thrombi, the kinetics of platelet activation were slower. Inhibiting platelet ADP P2Y receptors destabilized the shell and reduced thrombus size without affecting the core. Inhibiting thrombin with hirudin suppressed fibrin accumulation, but had little impact on thrombus size. Removing the platelet collagen receptor, glycoprotein VI, had no effect. Conclusions These results (i) demonstrate the feasibility of performing high-speed fluorescence imaging in larger vessels and (ii) highlight differences as well as similarities in the hemostatic response in the macro- and microcirculation. Similarities include the overall core-and-shell architecture. Differences include the slower kinetics of platelet activation and a smaller contribution from thrombin, which may be due in part to the greater thickness of the arterial wall and the correspondingly greater separation of tissue factor from the vessel lumen.
开发了用于实时成像小鼠股动脉止血反应的基本方法。穿透性损伤产生的血栓主要由血小板组成。与小动脉类似，股动脉中发生血小板活化的核壳结构。与小动脉的差异包括血小板活化较慢和凝血酶依赖性降低。
背景 在小鼠微循环中进行的活体研究表明，穿透性损伤后形成的止血血栓具有特征性结构，其中完全活化、紧密堆积的血小板核心被一层活化程度较低的血小板覆盖。目的 血液动力学和血管壁生物学的巨大差异区分了动脉和小动脉。在这里，我们询问这些差异是否会影响止血反应，并改变抗凝剂和抗血小板药物的作用。方法 先前为小鼠微循环活体成像开发的方法被应用于股动脉，尽管血管壁明显更厚，但仍能进行实时荧光成像。结果 穿透性损伤引发的动脉血栓形成了先前在微循环中观察到的核壳结构。然而，尽管动脉血栓中的血小板聚集更多，但血小板活化的动力学较慢。抑制血小板 ADP P2Y 受体使壳层不稳定并减小血栓大小，而不影响核心。用水蛭素抑制凝血酶可抑制纤维蛋白积累，但对血栓大小影响不大。去除血小板胶原受体糖蛋白 VI 没有效果。结论 这些结果（i）证明了在较大血管中进行高速荧光成像的可行性，（ii）突出了大循环和微循环中止血反应的差异和相似之处。相似之处包括整体的核壳结构。差异包括血小板活化动力学较慢以及凝血酶的贡献较小，这可能部分归因于动脉壁更厚以及组织因子与血管腔的相应更大距离。
