A systems approach to hemostasis and thrombosis

止血和血栓形成的系统方法

基本信息

批准号：
10434811
负责人：
LAWRENCE F BRASS
金额：
$ 55.14万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-05-10 至 2025-04-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10434811
关键词：
3-Dimensional Agonist Alpha Granule Antibodies Antiplatelet Drugs Architecture Arkansas Arteries Blood Platelets Blood Vessels Blood flow Brain Carotid Arteries Clot retraction Coagulation Process Collaborations Complex Computer Models Convection Coronary artery Defect Devices Diffusion Engineering Environment Event Face Fibrin Goals Heart Hemorrhage Hemostatic Agents Hemostatic function Human Hybrids Image Individual Injury Measures Methods Microfluidic Microchips Microscopy Molecular Mus Myocardial Infarction Natural Immunity Pathologic Phospholipids Physiological Platelet Activation Platelet Count measurement Process Regulation Research Personnel Resolution Role Scanning Electron Microscopy Schools Sepsis Shapes Stroke Structure Structure of jugular vein Surface Surgeon Syndrome System Testing Thrombin Thrombosis Thrombus Tissues Translating Trauma Universities Variant Veins Venous Thrombosis Work blood damage cerebrovascular computer studies density improved in vivo inhibitor m-calpain mu-calpain novel physical property platelet function prevent reconstruction regional difference response scale up submicron systemic inflammatory response thrombotic tumor growth vascular injury

项目摘要

Project 3 Abstract Platelet activation is critical for hemostasis and a contributing factor in thrombosis. Although recent studies have highlighted roles for platelets in diverse processes, the rapid accumulation of large numbers of platelets remains the hallmark of hemostasis and arterial thrombosis, and is the major focus of this project. Our recent studies in the mouse microvasculature show that the hemostatic response to small injuries produces a relatively simple structure in which a core of fully-activated platelets is overlaid by a shell of less-activated platelets. Dense packing in the core acts as a molecular trap, establishing an environment in which diffusion replaces convection. This structure allows thrombin and other agonists to form overlapping gradients that produce regional differences in platelet activation and fibrin distribution. Recognizing that transport is regulated by platelet packing density is a paradigm shift, suggesting that platelet procoagulant activity arises from forming a sheltered environment and not just from phospholipid exposure. We believe that this concept is key to understanding the impact of antiplatelet agents and the events of arterial thrombosis. Testing it calls for scaling up to larger injuries in larger vessels, and for extending our analysis from mice to humans and from hemostasis to thrombosis, all with a hybrid experimental and computational approach that integrates with and supports the other projects in this PPG. Aim #1 will examine the spatial and temporal distribution of platelet activation at high resolution, measure transport in the gaps between platelets, and examine the hemostatic response in large arteries and veins. The initial results show a more complex architecture with regions of greater and lesser platelet activation and packing density, and large differences between the luminal and abluminal surfaces. Our subcontract with Brian Storrie at the University of Arkansas will allow 3-dimensional reconstruction of larger hemostatic thrombi at the sub-micron level. In collaboration with Project 4 we will examine the impact of sepsis and systemic inflammation on platelet function in vivo and support studies on the impact of the PF4-directed antibody, KKO. Studies with µ- and m- calpain deficient mice will support work in Project 2, but also be part of understanding the role of clot retraction in limiting transport through larger hemostatic structures. Aim #2 will examine the mechanisms that shape the hemostatic plug, testing the hypothesis that hemostatic structure requires tight regulation of the extent of platelet activation and the delivery of platelet cargoes deep within the hemostatic mass. Studies on NBEAL2-/- (gray platelet syndrome) mice and the “empty a-granule” mice developed in Project 1 will allow us to examine the role of secretion on hemostatic plug architecture. Aim #3 will determine whether the ordered hemostatic structure that we have observed in mice applies to humans, and how it differs in arterial thrombosis as compared to hemostasis. The human studies will be performed in vivo with Penn trauma surgeon, Carrie Sims, and ex vivo using a novel microfluidics device developed with Dan Huh in Penn’s School of Engineering. Studies of human arterial thrombi will be done in collaboration with Project #2 co-investigator John Weisel.

项目3摘要尽管最近的研究表明，血小板活化对于止血至关重要，也是血栓形成的一个促成因素。强调了血小板在不同过程中的作用，大量血小板的快速积累仍然存在止血和动脉血栓形成的标志，也是我们最近研究的重点。小鼠微血管系统显示，对小损伤的止血反应产生相对简单的其结构是，完全活化的血小板核心被活化程度较低的致密血小板外壳所覆盖。核心中的堆积起到分子陷阱的作用，建立了一个扩散取代对流的环境。这种结构允许凝血酶和其他激动剂形成重叠梯度，从而产生区域差异认识到运输是由血小板堆积密度调节的。范式转变，表明血小板促凝血活性源于形成一个受庇护的环境和不仅仅是磷脂暴露，我们相信这个概念是理解影响的关键。抗血小板药物和动脉血栓形成事件需要扩大到更大范围的损伤。血管，并将我们的分析从小鼠扩展到人类，从止血扩展到血栓形成，所有这些都具有混合实验和计算方法，与该 PPG 中的其他项目集成并支持其他项目。目标#1将以高分辨率检查血小板活化的空间和时间分布，测量血小板之间间隙的运输，并检查大动脉和静脉的止血反应。初始区域显示出更复杂的结构，具有更大或更小的血小板激活和堆积密度，以及腔内和近腔表面之间的巨大差异我们与 Brian Storrie 的分包合同。阿肯色大学将允许对亚微米级较大止血血栓进行 3 维重建与项目 4 合作，我们将研究败血症和全身炎症对血小板的影响。体内功能并支持针对 PF4 的抗体的影响研究，KKO 使用 µ- 和 m- 进行的研究。缺乏钙蛋白酶的小鼠将支持项目 2 的工作，同时也是理解血块收缩作用的一部分目标#2将研究塑造止血结构的机制。止血塞，检验止血结构需要严格调节血小板程度的假设 NBEAL2-/-（灰色）止血块内血小板货物的激活和输送研究。血小板综合征）小鼠和项目 1 中开发的“空 a 颗粒”小鼠将使我们能够检查其作用目的#3将决定止血结构是否有序。我们在小鼠身上观察到的结果也适用于人类，以及与人类相比，它在动脉血栓形成方面有何不同人体研究将由宾夕法尼亚大学创伤外科医生 Carrie Sims 进行体内研究，以及离体研究。使用宾夕法尼亚大学人类工程研究学院的 Dan Huh 开发的新型微流体装置。动脉血栓治疗将与项目 #2 联合研究员 John Weisel 合作完成。