Molecular Imaging of Platelets and Oxidative Stress in Atherosclerosis

摘要 心血管疾病的非侵入性活体分子成像方法已被大量开发 部分是因为它们具有改善病人护理的潜力。这些方法已经在以下方面发挥了重要作用 研究环境，以发现潜在的可治疗的病理生物学和评估新的治疗方法在临床和前期 临床研究。我们实验室开创了新的对比增强超声(CEU)分子成像技术 依靠检测胶囊微泡(MB)造影剂的技术。这种方法 独一无二的内皮-血池界面特征。在本奖项的前一个资助期，我们使用了 CEU分子成像更好地了解内皮激活和血小板-内皮相互作用 有助于促进动脉粥样硬化的早期形成，并有助于慢性晚期动脉粥样硬化的高危特征。 我们证明，血小板黏附的发生主要是由于过度的内皮相关血管病变。 威勒布兰德因子(VWF)，发生在氧化应激增加的情况或区域。的总目标是 这项建议是为了利用这一知识来评估急性胰腺炎的潜在可治疗来源。 可归因于血小板的促炎和促血栓作用的心血管并发症 在大血管或冠脉微循环中与内皮细胞的粘连。我们还将测试小说 预防这些事件的疗法。在目标1中，炎症激活、VWF和血小板的分子成像 动脉粥样硬化小鼠的粘附性将被用来表征局灶性血管内皮细胞事件后发生的全局内皮事件 缺血事件(心肌梗死[MI]或急性肢体缺血)，我们认为这有助于远程 非罪魁祸首动脉的斑块激活。我们还将测试血小板-内皮细胞的相互作用是否有助于 远程斑块炎症；并将评估基于其潜力的创新治疗策略 减少内皮细胞VWF和抑制血小板-内皮细胞相互作用，包括ROS和 因数XI(FXI)。在目标2中，我们将把CEU分子成像和灌注成像的数据整合到不同的 基因靶向的心肌梗死小鼠品系对VWF介导的血小板的影响 微血管黏附无复流、再灌注后炎症反应和梗塞面积。再一次，我们会 测试创新的药物干预措施，能够挽救负责 预防过量的内皮VWF(ADAMTS13)，包括ROS和FXI的抑制剂，以及重组 ADAMTS13.在目标3中，心肌缺血-再灌注损伤将在肥胖、动脉粥样硬化的非 人类灵长类动物(吃西式饮食的恒河猴2年)。我们将整合来自分子的数据 成像、灌注成像和形态成像，以评估AIM 1和 目标2用于预防：(A)受损的微血管复流；或(B)颈动脉中的远程斑块激活 心肌梗塞后的动脉。这些研究被设计为一种转换模型，以测试有效性、机制证明和 我们可以在人体上应用的疗法的安全性。

SUMMARY Methods for non-invasive in vivo molecular imaging of cardiovascular disease have been developed, in large part, for their potential to improve patient care. These methods are already playing an important role in the research setting to discover potentially treatable pathobiology and to assess new therapies in clinical and pre- clinical studies. Our laboratory has pioneered novel contrast-enhanced ultrasound (CEU) molecular imaging techniques that rely on the detection of encapsulated microbubble (MB) contrast agents. This approach uniquely characterizes the endothelial-blood pool interface. In the prior funding period of this award, we used CEU molecular imaging to better understand how endothelial activation and platelet-endothelial interactions help to promote early atherogenesis and contribute to high-risk features in chronic late-stage atherosclerosis. We demonstrated that platelet adhesion occurs primarily because of excess endothelial-associated Von Willebrand factor (VWF) that happens in situations or regions of increased oxidative stress. The overall goal of this proposal is to leverage this knowledge in order to evaluate potentially treatable origins of acute cardiovascular complications that are attributable to the pro-inflammatory and pro-thrombotic effects of platelet adhesion to the endothelium, either in large vessels or the coronary microcirculation. We will also test novel therapies that prevent these events. In Aim 1, molecular imaging of inflammatory activation, VWF, and platelet adhesion in atherosclerotic mice will be used to characterize global endothelial events that occur after a focal ischemic event (myocardial infarction [MI] or acute limb ischemia), and that we believe contribute to remote plaque activation in non-culprit arteries. We will also test whether platelet-endothelial interactions contribute to remote plaque inflammation; and will assess innovative treatment strategies that are based on their potential to reduce endothelial VWF and suppress platelet-endothelial interactions, including inhibitors of ROS and of Factor XI (FXI). In Aim 2, we will integrate data from CEU molecular imaging and perfusion imaging in various gene-targeted murine strains undergoing MI in order to assess the contribution of VWF-mediated platelet adhesion to microvascular no-reflow, post-reperfusion inflammatory response, and infarct size. Again, we will test innovative pharmacologic interventions capable of rescuing the activity of the enzyme responsible for preventing excess endothelial VWF (ADAMTS13), including inhibitors of ROS and FXI, and recombinant ADAMTS13. In Aim 3, myocardial ischemia-reperfusion injury will be performed in obese, atherosclerotic non- human primates (rhesus macaques on Western diet for >2 years). We will integrate data from molecular imaging, perfusion imaging, and morphologic imaging to evaluate the most promising therapies from Aim 1 and Aim 2 for preventing either: (a) impaired microvascular reflow; or (b) remote plaque activation in the carotid artery after MI. These studies are designed as a translational model to test efficacy, proof-of-mechanism, and safety of therapies that we can then apply in humans.