(682c) A Novel, Thrombo-Inflammatory Model to Study Platelet Adhesion and Thrombogenesis in Vitro

Introduction: Platelets are responsible for maintaining hemostasis by plugging any interruptions or injuries in the vasculature, preventing blood loss and damage due to vascular injury. However, platelets also play a major role in the formation of pathological vascular thrombosis development, including atherosclerosis, stroke, myocardial infarction, and deep vein thrombosis. While the contribution of platelets in thrombus development has long been established, more recent research has illuminated the impact of the endothelium and the innate immune system in thrombogenesis. More specifically, the endothelium recruits and facilitates binding of platelets, leukocytes, and leukocyte-platelet aggregates under inflammatory conditions. Despite the importance of cells other than platelets, including neutrophils and the endothelium, in thrombosis development, most in vitro models studying platelet adhesion and aggregation neglect the role that inflammation and other cell types play in thrombosis development and resolution.

Materials and methods: We developed an in vitro flow-based system to more accurately represent the inflammatory environment that facilitates the development of thrombi in blood vessels. Human whole blood is perfused over an activated, damaged endothelial cell monolayer representing an acute vascular injury with underlying inflammation through a parallel-plate flow chamber using a syringe pump. After perfusion, adhesion of both leukocytes and platelets is quantified using fluorescent and transmitted light microscopy and compared to non-inflamed controls.

Results and conclusions: The inclusion of endothelial cell inflammation drastically impacts the level of adhesion of cells to the damaged endothelium in blood flow and in particular, highlights the role of leukocyte-platelet aggregates in thrombosis development. We demonstrate the utility of this model in several ways; first, the in vitro model allows us to better understand the mechanism of thrombo-inflammation, specifically by allowing the study of platelet-leukocyte-endothelium interactions in blood flow. Further, this model serves as a platform for evaluating therapeutic efficacy of early, novel therapeutics designed to interfere with platelet or leukocyte adhesion and interactions in thrombus development. Overall, we demonstrated that this model better serves as a sophisticated platform for the study of thrombo-inflammation in vitro.