Heart Research Institute, Newtown, NSW, 2042, Australia.
School of Biomedical Engineering, Faculty of Engineering, The University of Sydney, Darlington, NSW, 2008, Australia.
Analyst. 2022 Mar 14;147(6):1222-1235. doi: 10.1039/d2an00270a.
Microvascular thrombosis and inflammation (thromboinflammation) are major causes of morbidity and mortality in critically ill patients with limited therapeutic options. Platelets are central to thromboinflammation, and microvascular platelet thrombi are highly effective at recruiting and activating leukocytes at sites of endothelial injury. Whilst parallel-plate flow chambers, microslides and straight microchannel assays have been widely used to recapitulate leukocyte adhesive behavior on 2-dimensional (2D) surfaces, none of these methods achieve high fidelity 3-dimensional (3D) geometries emulating microvascular platelet thrombi. As a result, the role of hydrodynamic factors in regulating leukocyte interactions with platelet thrombi remains ill-defined. Here, we report a microfluidic post model that allows visualization and analysis of neutrophil-platelet interactions in a 3D flow field. We have utilized the unique mechanosensitive features of platelets to enable selective micropatterning of the 3D posts with human or mouse platelets. By modulating the activation status of platelets, our method enables precise control of platelet surface reactivity and neutrophil recruitment. In addition, our microfluidic post assay accurately recapitulated the rolling stationary adhesion behavior of single neutrophils and demonstrated the efficacy of the P-selectin and Mac-1 blocking antibodies to reduce neutrophil recruitment and stationary adhesion, respectively. Moreover, the geometry of posts had a major influence on the efficiency of neutrophil recruitment and adhesion stability. This new post method highlights the importance of platelet 3D geometries in facilitating efficient, localized neutrophil recruitment. These findings have potentially important implications for the potent proinflammatory function of microvascular platelet thrombi.
微血管血栓形成和炎症（血栓炎症）是危重病患者发病率和死亡率的主要原因，而治疗选择有限。血小板是血栓炎症的核心，微血管血小板血栓在招募和激活内皮损伤部位的白细胞方面非常有效。虽然平行板流动室、微 slides 和直微通道测定法已广泛用于在 2 维（2D）表面上再现白细胞黏附行为，但这些方法都无法实现高度逼真的 3 维（3D）几何形状来模拟微血管血小板血栓。因此，流体动力学因素在调节白细胞与血小板血栓相互作用中的作用仍不清楚。在这里，我们报告了一种微流控后模型，该模型允许在 3D 流场中可视化和分析中性粒细胞-血小板相互作用。我们利用血小板的独特机械敏感特性，使人类或小鼠血小板能够选择性地对 3D 柱进行微图案化。通过调节血小板的激活状态，我们的方法能够精确控制血小板表面反应性和中性粒细胞的募集。此外，我们的微流控柱测定法准确地再现了单个中性粒细胞的滚动固定黏附行为，并证明了 P-选择素和 Mac-1 阻断抗体的有效性，分别降低了中性粒细胞的募集和固定黏附。此外，柱的几何形状对中性粒细胞募集的效率和黏附稳定性有重大影响。这种新的柱方法强调了血小板 3D 几何形状在促进有效、局部中性粒细胞募集方面的重要性。这些发现对于微血管血小板血栓的强烈促炎功能具有潜在的重要意义。
