Von Willebrand Factor Hyperactivity, Angiogenesis and LVAD-Induced Bleeding

血管性血友病因子过度活跃、血管生成和 LVAD 诱发的出血

• 批准号: 10587655
• 负责人: Angelo Nascimbene
• 金额: $ 62.23万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-10 至 2028-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10587655
• 关键词: ADAMTS; Acquired von Willebrand disease; Adhesiveness; Adhesives; Angiodysplasia; Arteriovenous malformation; Artificial Intelligence; Binding; Biological Assay; Biophysics; Blood; Blood Platelets; Blood Vessels; Blood flow; Blood specimen; Cardiac; Clinical; Clinical Management; Clinical Research; Complication; Data; Devices; Endothelial Cells; Ensure; Equilibrium; Exposure to; Extracorporeal Membrane Oxygenation; Flow Cytometry; Functional disorder; Generations; Heart; Heart Diseases; Hemorrhage; Hemostatic Agents; Hemostatic function; Homeostasis; Hyperactivity; Impairment; Implant; In Vitro; Institution; Laboratories; Ligands; Link; Machine Learning; Mass Spectrum Analysis; Mediating; Metalloproteases; Methods; Microfluidics; Modeling; Morbidity - disease rate; Mucous Membrane; Multivariate Analysis; Mus; Operative Surgical Procedures; Outcome; Pathology; Patients; Pattern; Peptides; Plasma; Process; Pump; Reporting; Research; Risk; Role; Sampling; Source; System; Techniques; Technology; Testing; Therapeutic Agents; Thrombosis; Vascular Endothelial Growth Factors; angiogenesis; biophysical analysis; biophysical techniques; cleavage factor; design; experience; experimental study; extracellular vesicles; gain of function; implantable device; implantation; improved; in vivo; innovation; insight; left ventricular assist device; longitudinal analysis; loss of function; mouse model; predictive marker; prevent; shear stress; synergism; therapeutic target; von Willebrand Factor; von Willebrand factor receptor

Project Summary Left ventricular assist device (LVAD) provides cardiac support for patients with end stage heart disease and has significantly improved the survival of these patients, but device-related bleeding remains common and are associated with poor clinical outcomes. Even latest (3rd) generation devices have been able to significant impact device thrombosis (e.g.MOMENTUM3 trial), however with some surprise they have not been able to resolve LVAD related bleeding which remains a significant source of morbidity and complicates clinical management, ultimately leading to poor clinical outcomes. The LVAD-associated bleeding is often called acquired von Willebrand syndrome (aVWS) that is believed to be caused by excessive cleavage of VWF multimers by ADAMTS-13. However, this tentative mechanism has not been experimentally validated and significant gaps remain. The loss of large VWF multimers is observed in nearly all patients, but only a fraction of patients experience significant bleeding. High shear stress is known to promote VWF cleavage and activation to bind platelets, but this shear-induced VWF activation has not been studied in patients on LVAD. We hypothesize that: 1) Plasma VWF multimers in LVAD patients are subjected to higher rates of cleavage and activation than healthy subjects and patients with end stage heart disease prior to LVAD implant 2) LVAD- induced high shear stress results in VWF dysfunctions responsible for impaired hemostasis and triggers downstream VWF mediated angiogenesis 3) These shear-induced structural changes of VWF can be detected in patients on LVAD and can predict bleeding propensity developed after LVAD implantation. We propose to test these hypotheses with three specific aims. First, develop predictive markers for LVAD-induced hemostatic complications by comprehensively analyzing the imbalance between VWF activity and cleavage in longitudinal plasma samples from 240 patients collected before and after LVAD implantation using flow cytometry, mass spectrometry, microfluidic chamber systems, and conventional VWF functional tests. Second, study shear- induced structural changes of the VWF A1 and A2 domains and their roles in regulating rates of VWF cleavage and activation using in vitro techniques and mouse models. Third study how VWF synergizes with extracellular vesicles to promote immature angiogenesis, which leads to bleeding-prone arteriovenous malformation. The objectives of this mechanistic study are to: 1) define shear-induced structural changes of VWF using state-of- art biophysical techniques and study how these changes influence VWF cleavage and activity, 2) study how high shear stress disrupts the inhibitory interaction between the A1 and A2 domains to alter the A1 interface with the platelet VWF receptor GP Ib and to unfold A2 for cleavage, and 3) investigate the role of VWF in angiogenesis. We have assembled a team of experts in related clinical and research fields from 3 institutions to conduct this innovative research focused on improving LVAD outcomes and provide insight on how aVWS may play a role in surgical and percutaneous continuous flow devices.

项目概要 左心室辅助装置 (LVAD) 为患有终末期心脏病的患者提供心脏支持 显着提高了这些患者的生存率，但与设备相关的出血仍然很常见，并且 与不良的临床结果相关。即使是最新的（第三代）设备也能够显着 冲击装置血栓形成（例如 MOMENTUM3 试验），但令人惊讶的是他们未能 解决 LVAD 相关出血问题，该出血仍然是发病率的重要来源并使临床复杂化 管理，最终导致不良的临床结果。 LVAD 相关的出血通常称为 获得性血管性血友病综合征 (aVWS)，被认为是由 VWF 过度裂解引起的 ADAMTS-13 的多聚体。然而，这一暂定机制尚未经过实验验证， 仍然存在重大差距。几乎所有患者都观察到大 VWF 多聚体的丢失，但只有一小部分患者 的患者经历严重出血。众所周知，高剪切应力会促进 VWF 裂解， 激活结合血小板，但这种剪切诱导的 VWF 激活尚未在接受 LVAD 的患者中进行研究。 我们假设：1) LVAD 患者血浆 VWF 多聚体的裂解率更高 和激活率高于健康受试者和 LVAD 植入前患有终末期心脏病的患者 2) LVAD- 诱导的高剪切应力导致 VWF 功能障碍，导致止血受损和触发 下游 VWF 介导的血管生成 3) 可以检测到这些剪切诱导的 VWF 结构变化 接受 LVAD 的患者可以预测 LVAD 植入后出现的出血倾向。我们建议 通过三个具体目标来检验这些假设。首先，开发 LVAD 诱导止血的预测标记物 通过综合分析VWF活性和纵向裂解之间的不平衡来解决并发症 使用流式细胞仪收集 240 名患者在 LVAD 植入前后的血浆样本，质量 光谱测定法、微流体室系统和传统的 VWF 功能测试。二、研究剪切—— 诱导 VWF A1 和 A2 结构域的结构变化及其在调节 VWF 裂解速率中的作用 并使用体外技术和小鼠模型进行激活。第三项研究 VWF 如何与细胞外协同作用 囊泡促进未成熟的血管生成，从而导致容易出血的动静脉畸形。这 该机制研究的目标是：1）使用状态定义 VWF 剪切引起的结构变化 艺术生物物理技术并研究这些变化如何影响 VWF 裂解和活性，2) 研究如何 高剪切应力破坏 A1 和 A2 结构域之间的抑制相互作用，从而改变 A1 界面 与血小板 VWF 受体 GP Ib 结合并展开 A2 进行裂解，3) 研究 VWF 在 血管生成。我们集结了来自3个机构的相关临床和研究领域的专家团队 开展这项创新研究，重点是改善 LVAD 效果，并提供有关 aVWS 如何进行的见解 可能在手术和经皮连续流装置中发挥作用。