Basic mechanisms in arteriovenous fistula maturation for hemodialysis

描述(由申请人提供)： 项目概述/摘要提名者：本提案描述了一项为期三年的培训计划，该计划旨在以退伍军人医学中心为中心，发展候选人在血管外科的学术生涯。这位候选人在明尼阿波利斯退伍军人学院接受了3年的正式研究培训，获得了NIH F32 NRSA奖学金，致力于研究内膜增生，这是手术损伤后血管重塑的一种病理形式。在研究金中，候选人发表了15篇同行评议的出版物，其中8篇为第一作者，6篇与NRSA项目直接相关。这笔奖学金导致了一篇博士论文的成功答辩。这位候选人通过血管重塑的翻译方法继续他的研究兴趣，评估肾功能衰竭患者动静脉瘘(AVF)构建后静脉重塑的机制。在过去的一年里，候选人发表了3篇与该领域相关的同行评议稿件，其中1篇是第一作者。假设：候选人计划测试假设，即单核细胞-内皮细胞黏附继而迁移导致内皮屏障损伤，并削弱基质金属蛋白酶(MMP)的产生和活性，导致AVF成熟失败。具体目的：(1)评价血液透析患者血液和静脉段MMPs和单核细胞黏附分子在预测AVF成熟度中的作用。(2)探讨单核细胞-内皮细胞相互作用在内皮屏障功能障碍和基质金属蛋白酶调节失调导致内瘘失败的分子机制。相关性：失败比成功更常见(失败率为30%-60%)的血管手术是外科手术构建用于血液透析通路的成熟的自体动静脉瘘。该项目强调血细胞和内皮细胞在血管损伤中的相互作用，并着眼于识别新的诊断工具和分子靶点，以改善AVF的预后。研究对象：所有有肾功能不全或肾功能衰竭的退伍军人患者。使用的程序：将对接受血液透析手术的患者的静脉段和血液进行分子分析。将使用以下实验程序来验证所述假设：7从外周血中分离和纯化单核细胞。7明胶酶谱和免疫印迹蛋白定量(MMPs)。7细胞黏附分子的流式细胞仪检测；7细胞-底物阻抗传感技术；7单核细胞内皮迁移和内皮通透性的Transwell检测；7生物统计学：多因素分析和生存分析(静脉成熟度和持续时间)；7患者管理和病例报告表管理。潜在新发现的意义：在描述动静脉瘘重建后静脉重构的机制方面可以获得重要的洞察力。如果能开发出可靠的生物标记物，某些患者有可能被选为替代血液透析途径，如初级桥接移植物。此外，更深入地了解这一机制可能会导致临床试验，评估减少单核细胞-内皮细胞相互作用的药物治疗，如他汀类药物。如果成功，动静脉瘘的成熟率将提高，重复手术的需要将降至最低。

DESCRIPTION (provided by applicant): Project Summary/Abstract NOMINEE: This proposal describes a three year training program to develop a candidate's academic career in Vascular Surgery centered at a VA medical center. The candidate spent 3 years in formal research training at the Minneapolis VA with an NIH F32 NRSA fellowship grant working on intimal hyperplasia, a pathologic form of vascular remodeling after surgical injury. From the fellowship, the candidate published 15 peer-reviewed publications, 8 as first author and 6 directly related to the NRSA project. The fellowship led to the successful defense of a PhD thesis. The candidate has continued his research interests through a translational approach to vascular remodeling assessing the mechanisms of vein remodeling after arteriovenous fistula (AVF) construction for renal failure patients. In the past year, the candidate has published 3 peer-reviewed manuscripts related to this area, 1 as first author. HYPOTHESIS: The candidate plans to test the hypothesis that monocyte-endothelial cell adhesion followed by transmigration induces endothelial barrier injury and impairs Matrix Metalloproteinase (MMP) production and activity, leading to the failure of AVF maturation. SPECIFIC OBJECTIVES: (1) To evaluate the biomarker role of MMPs and monocyte adhesion molecules in the blood and vein segment of hemodialysis patients for predicting AVF maturation. (2) To investigate the molecular mechanisms of monocyte-endothelial cell interactions in endothelial barrier dysfunction and MMP dysregulation, leading to fistula failure. RELEVANCE: A vascular procedure where failure is more common (30-60% failure rate) than success is the surgical construction of a mature autogenous AVF for hemodialysis access. This project emphasizes the interactive roles of blood cells and endothelial cells in vascular injury, with a practical view on the identification of new diagnostic tools and molecular targets for improved AVF outcome. SUBJECT POPULATION: All Veteran patients with renal insufficiency or renal failure. PROCEDURES TO BE USED: Molecular analyses will be performed in vein segments and blood from patients undergoing hemodialysis access surgery. The following experimental procedures will be used to test the stated hypothesis: 7 Isolation and purification of monocyte isolation from peripheral blood. 7 Gelatinase zymography and Western immunoblot quantification of protein (MMPs) expression. 7 Flow cytometric measurement of adhesion molecules 7 Electric Cell-substrate Impedance Sensing (ECIS) technique 7 Transwell assays of monocyte transendothelial migration and endothelial permeability 7 Biostatistics: Multivariate analysis and survival analysis (vein maturation and duration) 7 Patient management and case report form management. SIGNIFICANCE OF POTENTIAL NEW FINDINGS: Important insight can be gained in describing the mechanism for vein remodeling after AVF construction. If reliable biomarkers can be developed, certain patients could potentially be selected for alternative hemodialysis access such as a primary bridge graft. Furthermore, greater insight into the mechanism could lead to clinical trials evaluating medical therapies that decrease monocyte-endothelial cell interactions, such as statins. If successful, maturation rates for AVF would improve and the need for repeat surgery minimized.