The Role of Hypoxia In Venous Neointimal Hyperplasia In Hemodialysis Grafts

描述(由申请人提供)： 项目描述：美国有超过40万名患者患有终末期肾病(ESRD)，预计在接下来的十年中，这一人口将翻一番。目前这一提议和研究计划的长期目标是改善终末期肾病患者的护理，绝大多数患者使用长期血液透析作为肾脏替代治疗的模式。这些患者需要高功能的血管通路才能获得最佳的治疗充分性。血液透析血管通路失败的常见原因是静脉狭窄继发于新生内膜增生(VNH)。我们研究的初步数据表明，VNH的形成可能有几种机制。这包括：1)缺氧诱导因子-1α(HIF-11)升高，然后刺激；2)血管内皮生长因子-A(VEGF-A)及其受体的表达增加；3)基质金属蛋白酶-2(MMP2)和明胶酶(MMP9)的表达增加；4)成纤维细胞从外膜和中膜向内膜的增殖和迁移，导致VNH的形成。我们已经开发了最先进的分子试剂，并验证了动静脉瘘模型(AVF)和低氧成纤维细胞培养模型的小鼠肾切除。体外和体内的模型和伴随的试剂使我们能够严格检验我们的中心假设：当增加的HIF-11刺激外膜成纤维细胞分化为肌成纤维细胞(1-SMA阳性细胞)时，就会发生静脉新生内膜增生。HIF-11调控蛋白的表达增加导致肌成纤维细胞的增殖和向内膜迁移，导致VNH的形成。为了验证我们的中心假设，我们制定了三个具体目标：1)。确定血管内皮生长因子-A在VNH中的时空作用(S)。2)。确定MMPs在VNH中的作用(S)及其调控。3)。确定低氧诱导成纤维细胞向肌成纤维细胞分化的分子机制是否由血管内皮生长因子-A/基质金属蛋白酶轴介导。这些目标的成功实现将使我们能够最终将旨在抑制VNH的疗法转化为临床试验，从而使用可以使用基于导管的技术提供的商用抗血管内皮生长因子-A抗体(阿瓦斯丁(Bevacizumab))和基质金属蛋白酶抑制剂(辛伐他汀或西罗莫司)来改善患者的预后。

DESCRIPTION (provided by applicant): Project description: More than 400,000 patients in the US have end stage renal disease (ESRD), a population expected to double in the next decade. The long term goal of this current proposal and research program is to improve the care of patients with ESRD, the vast majority of who use long-term hemodialysis as their mode of renal replacement therapy. These patients require highly functioning vascular access for optimal therapeutic adequacy. Hemodialysis vascular access failure is frequently from venous stenosis secondary to neointimal hyperplasia (VNH). Preliminary data from our studies indicate that several mechanisms may be responsible for VNH formation. These include: 1) Elevated hypoxia inducible factor-1 alpha (HIF-11) which then stimulates; 2) Increased expression of vascular endothelial growth factor-A (VEGF-A) and its receptors; 3) Increased expression of matrix metalloproteinase-2 (MMP-2) and MMP-9 (gelatinases); and 4) Proliferation and migration of fibroblasts from the adventitia and media to the intima resulting in VNH formation. We have developed state- of-the art molecular reagents and validated mouse nephrectomy with arteriovenous fistula model (AVF) and a hypoxia fibroblast cell culture model. The in vitro and in vivo models and accompanying reagents allow us to rigorously test our Central Hypothesis: Venous neointimal hyperplasia occurs when increased HIF-11 stimulates adventitial fibroblasts to differentiate into myofibroblasts (1-SMA positive cells). Increased expression of HIF-11 regulated proteins including VEGF-A, MMP-2 and MMP-9 results in the proliferation and migration of myofibroblasts into the intima leading to the formation of VNH. To test our central hypothesis we have developed three specific aims: 1). Determine the temporal and spatial role(s) of VEGF-A in VNH. 2). Determine the role(s) and regulation of MMPs in VNH. 3). Determine if the molecular mechanism of hypoxia induced fibroblast to myofibroblast differentiation is mediated by the VEGF- A/MMP axes. Successful completion of these aims will allow us to ultimately translate therapies aimed at inhibiting VNH to clinical trials thereby improving patient outcomes using commercially available anti-VEGF-A antibodies (Avastin (Bevacizumab)) and MMP inhibitors (Simvastatin or Sirolimus) which can be delivered using catheter based technology.