Analysis of shear stress-induced von Willebrand factor and platelet damage from ventricular assist devices

心室辅助装置剪切应力诱导的冯维勒布兰德因子和血小板损伤的分析

• 批准号: 2166784
• 金额: --
• 依托单位: Swansea University
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2166784
• 关键词: Analysis; shear; stress; induced; von

A ventricular assist device (VAD) supports heart function in people with heart failure. VADs pumps blood from the heart to various parts of the body. Although heart failure can be treated with VADs, bleeding remains a serious complication of long-term VAD use. Acquired von Willebrand Disease (aVWD) is due to the breakdown of high molecular weight (HMW) von Willebrand factor (vWF) multimers. vWF circulating in blood is cleaved by ADAMTS13 metalloprotease under high shear stress. HMW vWF multimers are required for platelet aggregation, which is critical for blood clotting. This study will investigate the loss of HMW vWF from blood under shear stress. Therefore, the hypothesis of this project is that inhibition of ADAMTS13 can restore HMW vWF multimers and vWF function. This hypothesis will be tested by using the following three aims:1. To analyse the effect of ADAMTS13 inhibition on the levels and activity of HMW vWF multimers in blood. The loss of HMW multimers and activity of vWF exposed to shear stress will be analysed in the presence or absence of ADAMTS13 inhibitors. Blood will be analysed by immunoblotting and platelet aggregation, flow cytometry and confocal microscopy. 2. To study the levels and activity of HMW vWF multimers in blood passed through a VAD in vitro or by cardiopulmonary bypass (CPB) circuit. The vWF HMW multimers and activity in plasma of blood of healthy volunteers passed through a VAD or heart patients passed through CPB circuit during bypass surgery will be assessed by immunoblotting and platelet aggregation. This is to determine if mechanical shear stress differentially affects blood from healthy volunteers and heart failure patients. Since it is impossible to obtain 2000 mL of blood, which is required to pump through a VAD in vitro, we will be using blood obtained during bypass surgery in this study.3. To analyse the levels of vWF HMW multimers and activity in plasma of patients and sheep implanted with a VAD. The plasma samples obtained from a VAD implanted sheep (Calon Cardio Technology Ltd/Catholic Univ. of Leuven) and human patients (from HDZ-NRW) will be used to assess the HMW multimer levels (by immunoblotting) and the activity (by platelet aggregation) of vWF. This analysis will be useful to study the effect of shear stress-induced ADAMTS13 HMV vWF multimers loss in real physiological conditions.Significance: Heart failure is the UK's biggest killer. Since the availability of heart donors for transplantation has declined, VAD implantation has become an option for bridge to transplantation or destination therapy. Therefore, it becomes pertinent to understand the consequences of long-term VAD usage on the quality of life of patients. Acquired von Willebrand syndrome, a bleeding disorder, is common in VAD implanted patients. The proposed research will, therefore, be useful in the development of lower blood damage VADs.The proposed project is within Clinical Devices of EPSRC research topic. The research will be beneficial in designing VADs with less side-effects highlighting the translation to healthcare applications. The project will advantage the development of new healthcare solutions that comes under the Developing Future Therapies grand challenge of the theme.

心脏辅助装置(VAD)支持心力衰竭患者的心功能。VADs将血液从心脏输送到身体的不同部位。虽然心力衰竭可以用VAD治疗，但出血仍然是长期使用VAD的严重并发症。获得性von Willebrand病(AVWD)是由于高分子量(HMW)von Willebrand因子(VWF)多聚体的分解所致。在高切应力下，血液中循环的VWF被ADAMTS13金属蛋白酶切割。HMW vWF多聚体是血小板聚集所必需的，而血小板聚集是凝血的关键。本研究将研究在切应力作用下血液中HMW vWF的损失。因此，本项目的假设是抑制ADAMTS13可以恢复HMW vWF多聚体和vWF功能。这一假说将通过以下三个目的来验证：1.分析ADAMTS13抑制对血液中HMW vWF多聚体水平和活性的影响。在存在或不存在ADAMTS13抑制剂的情况下，将分析剪切应力下HMW多聚体的损失和vWF的活性。血液将通过免疫印迹和血小板聚集、流式细胞仪和共聚焦显微镜进行分析。2.研究体外循环和体外循环血液中HMW vWF多聚体的水平和活性。采用免疫印迹法和血小板聚集法对体外循环期间通过VAD的健康志愿者和体外循环心脏病人的血浆vWF、HMW多聚体和活性进行检测。这是为了确定机械切应力是否会对健康志愿者和心力衰竭患者的血液产生不同的影响。由于在体外不可能获得需要通过VAD泵送的2000毫升血液，因此在本研究中我们将使用在搭桥手术中获得的血液。目的：分析VAD植入患者和绵羊血浆中vWF、HMW多聚体的水平和活性。从植入VAD的绵羊(Calon Cardio Technology Ltd/天主教大学)获得的血浆样本。(鲁汶)和人类患者(来自HDZ-NRW)将被用于评估(通过免疫印迹)HMW多聚体水平和(通过血小板聚集)vWF的活性。这一分析将有助于研究切应力诱导的ADAMTS13 HMV vWF多聚体在真实生理条件下丢失的影响。意义：心力衰竭是英国最大的杀手。由于供心脏移植的供者越来越少，VAD植入已成为过渡到移植或目的治疗的一种选择。因此，了解长期使用VAD对患者生活质量的影响变得有意义。获得性血管性血友病综合征是一种出血性疾病，在植入VAD的患者中很常见。因此，拟议的研究将有助于开发血液损害较低的VAD。该拟议的项目属于EPSRC的临床设备研究课题。这项研究将有助于设计副作用较少的VAD，突出向医疗保健应用的转化。该项目将有利于开发新的医疗保健解决方案，这是在主题为发展中的未来疗法的重大挑战下进行的。