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存活率，但与设备相关的出血仍然很常见，而且 与不良的临床结果相关。即使是最新的(第三代)设备也能够显著 Impact Device血栓形成(例如MOMENTUM3试验)，然而令人惊讶的是，他们还没有能够 解决LVAD相关出血，这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。与左前降支相关的出血通常称为 获得性血管性血友病综合征(AVWS)，据信是由vWF过度切割引起的 ADAMTS-13的万用表。然而，这一试探性的机制尚未得到实验验证和 巨大的差距仍然存在。几乎所有患者都有较大的vwf多聚体丢失，但只有一小部分患者有此现象。 的患者会经历大量出血。众所周知，高剪应力可以促进VWF的解理和 VWF激活与血小板结合有关，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患者的血浆VWF多聚体有较高的卵裂率 比健康受试者和终末期心脏病患者在LVAD植入前的激活和激活2) 诱导的高剪应力导致VWF功能障碍，导致止血功能受损和触发 VWF下游介导的血管生成3)这些剪切诱导的VWF结构变化可以被检测到 并且可以预测LVAD植入后的出血倾向。我们建议 用三个具体的目标来检验这些假设。首先，开发LVAD诱导止血的预测标记物 综合分析VWF活性和纵向裂解的失衡引起的并发症 用流式细胞仪检测240例左前降支患者植入前后的血浆样本 光谱分析、微流室系统和常规VWF功能测试。第二，研究剪切力。 VWF A1和A2结构域的诱导结构变化及其在调节VWF切割速率中的作用 以及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 小泡促进未成熟的血管生成，这会导致容易出血的动静脉畸形。这个 这项力学研究的目标是：1)确定VWF的剪切引起的结构变化，使用状态。 ART生物物理技术，并研究这些变化如何影响VWF的切割和活性，2)研究如何 高剪应力破坏A1和A2结构域之间的抑制相互作用，改变A1界面 与血小板vwf受体GP Ib结合，并展开A2进行切割，以及3)研究vwf在血管内皮细胞生长中的作用。 血管生成。我们组建了一支来自3个机构的相关临床和研究领域的专家团队 进行这项致力于改善LVAD结果的创新研究，并提供有关aVWS如何 可在外科和经皮连续流动装置中发挥作用。