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.

项目摘要 左心室辅助装置（LVAD）为终末期心脏病患者提供心脏支持， 显著提高了这些患者的生存率，但器械相关出血仍然很常见， 与不良临床结局相关。即使是最新的（第三代）设备也能够显著提高 冲击器械血栓形成（例如，MOMENTUM 3试验），但令人惊讶的是，他们未能 解决LVAD相关出血，这仍然是发病率的重要来源，并使临床并发症 管理，最终导致不良的临床结果。LVAD相关出血通常被称为 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 多聚体的ADAMTS-13。然而，这种尝试性的机制尚未得到实验验证， 仍然存在重大差距。在几乎所有的患者中都观察到大的VWF多聚体的丢失，但只有一小部分 的患者出现严重出血。已知高剪切应力促进VWF裂解， VWF激活结合血小板，但这种剪切诱导的VWF激活尚未在LVAD患者中进行研究。 我们假设：1）LVAD患者血浆VWF多聚体的裂解率较高 2）LVAD植入前的健康受试者和患有终末期心脏病的患者相比， 诱导的高剪切应力导致VWF功能障碍，导致止血受损， 3）这些剪切诱导的VWF结构变化可以被检测到， 在LVAD患者中，可以预测LVAD植入后的出血倾向。我们建议 用三个具体目标来检验这些假设。首先，开发LVAD诱导止血的预测标志物 综合分析VWF活性与卵裂的失衡， 使用流式细胞术，从LVAD植入前后收集的240例患者的血浆样品，质量 光谱法、微流体室系统和常规VWF功能测试。第二，研究剪切- 诱导的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 以及使用体外技术和小鼠模型进行活化。第三研究VWF如何与细胞外 囊泡促进不成熟的血管生成，从而导致出血倾向的动静脉畸形。的 该机制研究的目的是：1）使用状态- 艺术生物物理技术和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结构域之间的抑制性相互作用以改变A1界面 与血小板VWF受体GP Ib α结合并展开A2进行切割，以及3）研究VWF在 血管生成我们汇集了来自3个机构的相关临床和研究领域的专家团队 进行这项创新研究，重点是改善LVAD的结果，并提供有关AVWS如何 可以在外科手术和经皮连续流动装置中发挥作用。