Proteolytic Pathways in Venous Thrombus Resolution

背景/原理：静脉血栓栓塞症(VTE)是一种常见而严重的心血管疾病 死亡率和发病率都很高。深静脉血栓形成患者的即刻抗凝治疗 减少致命的肺栓塞(PE)，但不能预防VTE的长期发病率。血栓后 25%-50%的患者手臂和腿部深静脉有血栓，包括疼痛， 肿胀和复发性皮肤溃疡。DVT的常见危险因素包括癌症、重大创伤、手术、 瘫痪、长时间不动和年老。深静脉血栓及其并发症在 过去十年的退伍军人人数。部署的军事人员由于时间长而面临更大的风险 空中和地面运输、脱水、烟草使用和重症患者住院期间的长期不动 受伤。血栓溶解是血栓形成后综合征发病的关键因素，因为 血栓不完全溶解可导致血流受阻和静脉瓣膜功能丧失。使用小说 血栓体积的3D连续测量；我们证明，初始DVT相似的DVT患者有 尽管有足够的抗凝，随着时间的推移，血栓消退率差别很大。纵向研究 显示血栓消退速度快的患者比那些血栓消退快的患者预后更好 血栓消退的速度要慢得多。尽管它在临床上很重要，但涉及的细胞和分子机制 对深静脉血栓的治疗知之甚少，目前还没有加速这一过程的治疗方法。 目的：使用临床相关的深静脉血栓形成的实验模型，全面了解 协调精确炎症程序的细胞介导的分子过程开始出现， 构成了这项提议的基础。我们的目标是在我们之前的VA Merit调查结果的基础上：1)定义 纤溶酶原激活物抑制物-2(PAI-2)缺乏对炎性白细胞的调控机制 加速静脉血栓的溶解；2)检测阻断PAI-2途径对 加速静脉血栓的消退；以及3)确定颞叶炎症的特异性基因信号 静脉血栓消退过程中发生的血管重塑事件及其预后价值 静脉血栓栓塞术后血栓消退和适应不良患者的候选生物标记物。 方法：研究将利用基因缺陷小鼠在DVT的实验模型中准确地模仿 在人类深静脉血栓中观察到的许多临床和病理生理特征。我们将通过以下方式定义机制 哪种PAI-2缺乏症通过体外校准免疫调节来加速静脉血栓的溶解 溶栓试验、迁移试验和中性粒细胞过继转移试验。翻译型 抑制PAI-2表达或活性以加速静脉血栓溶解的可能性将在 在人类细胞和临床前模型中。最后，我们将使用我们已建立的临床相关小鼠模型 DVT分辨率，以识别基因调节信号/潜在生物标志物，然后评估基因变化 静脉血栓栓塞术后血栓消退患者血液中随时间变化的网络。 结果：在静脉血栓溶解过程中调节炎症的分子机制 将确定实验模型和在人类患者中的应用，并基于这些机制测试治疗方法 在临床前模型中。 现状：这是一个新项目，源于之前退伍军人事务部的大量支持性初步数据 奖品。 影响：来自这些研究的关于DVT患者炎症特征的新知识可能会形成 为加速这一过程的新疗法奠定基础，并与抗凝剂相结合，控制过量 纤维化，并预防这种疾病。

Background / Rationale: VTE (Venous Thromboembolism) is a common and serious cardiovascular disease with significant mortality and morbidity. Prompt anticoagulation of patients with deep venous thrombosis (DVT) reduces fatal pulmonary embolism (PE) but does not prevent long-term morbidity of VTE. Post-thrombotic syndrome occurs in 25-50% of patients with clots in the deep veins of the arms and legs that consists of pain, swelling, and recurrent skin ulceration. Common risk factors for DVT include cancer, major trauma, surgery, paralysis, prolonged periods of immobility, and older age. DVT and its complications have increased in the Veteran population over the last decade. Deployed military personnel are at an increased risk due to prolonged air and ground transport, dehydration, tobacco use, and extended immobility during hospitalizations for severe injuries. Thrombus resolution is a critical factor in the pathogenesis of post-thrombotic syndrome since incomplete thrombus resolution can result in obstruction of flow and loss of venous valve function. Using novel 3D serial measurements of thrombus volume; we demonstrated that DVT patients with similar initial DVTs have widely varying rates of thrombus resolution over time despite adequate anticoagulation. Longitudinal studies show that patients with more rapid thrombus resolution have a better prognosis than those patients whose thrombus resolves much slower. Despite its clinical importance, the cellular and molecular mechanisms involved in DVT are poorly understood, and there currently is no therapy to accelerate this process. Objectives: Using clinically relevant experimental models of DVT, a comprehensive picture of interconnected cell-mediated molecular processes that orchestrate a precise inflammatory program is starting to emerge and forms the foundation for this proposal. Our objectives are to build on our previous VA Merit findings to: 1) define mechanisms by which plasminogen activator inhibitor-2 (PAI-2) deficiency modulates inflammatory leukocytes to accelerate venous thrombus resolution; 2) test the therapeutic efficacy of blocking the PAI-2 pathway to accelerate venous thrombus resolution; and 3) determine specific gene signatures for the temporal inflammatory vascular remodeling events that occur during venous thrombus resolution and evaluate the prognostic value of candidate biomarkers in patients with evolving and maladaptive thrombus resolution after VTE. Methods: Studies will utilize genetically deficient mice in experimental models of DVT that accurately mimic many of the clinical and pathophysiological features observed in human DVT. We will define mechanisms by which PAI-2 deficiency calibrates immune regulation to accelerate venous thrombus resolution using ex vivo thrombolysis assays, transmigration assays, and neutrophil adoptive transfer experiments. The translational potential of suppressing PAI-2 expression or activity to accelerate venous thrombus resolution will be tested in human cells and in preclinical models. Finally, we will use our well-established clinically relevant mouse models of DVT resolution to identify gene regulatory signatures/potential biomarkers and then evaluate changes in gene networks over time in blood from patients with evolving thrombus resolution after VTE. Findings/Results: Molecular mechanisms that modulate inflammation during venous thrombus resolution in experimental models and in human patients will be identified and therapies based on these mechanisms tested in preclinical models. Status: This is a new project arising from substantial supportive preliminary data from a previous VA Merit Award. Impact: New knowledge from these studies regarding the inflammatory signatures in DVT patients may form the basis for novel therapies for accelerating this process, and in combination with anticoagulants, control excessive fibrosis, and prevent this disease.