Manipulating the matrix to improve arteriovenous fistula patency

项目摘要 人类疾病的几种常见疗法的基础是使用静脉作为一种管道 增加血液流量，如动静脉瘘(AVF)，这是血液透析的首选途径。然而， 动静脉瘘的成熟度和通畅性较差，特别是在妇女中，需要额外的重做手术和 手术，反映了我们对导致成功的静脉重塑生物学的不完全理解 静脉对动脉环境的适应。这种知识鸿沟创造了对小说的未得到满足的需求 增强静脉重塑从而提高静脉导管临床应用成功率的方法。 成功的静脉重塑需要细胞外基质(ECM)的沉积，使机械 抵抗每周3次用大口径针刺穿动静脉壁的血液透析程序的强度。 转化生长因子-β1调节多种细胞功能，包括细胞外基质沉积和 改建。我们提供了令人振奋的新数据：1)我们创新的AVF鼠标模型忠实地概括了 人动静脉瘘的成熟包括~1/3的失败率；2)动静脉动静脉瘘的雌性小鼠 3)在体内可以调控转化生长因子-β-1的功能，转化生长因子-β-1在体内是必需的。 成功的早期动静脉动静脉瘘重塑；4)在动静脉动静脉瘘失败的小鼠中，细胞外基质和晚期转化生长因子-β1的表达增加 和Smad2/tak1的磷酸化；5)手术后的人AVF中Smad2/tak1的磷酸化增加 6)我们开发了一种创新的纳米颗粒工具来在体内操纵转化生长因子-β1信号。 我们的数据表明，外科手术制造的瘘管通过Smad2/3刺激转化生长因子-β1的早期激活 和/或Tak1磷酸化，这对成功的早期静脉适应和AVF成熟至关重要。我们 假定晚期旺盛的转化生长因子-β1活性导致细胞外基质过度沉积和新生内膜 导致动静脉动静脉瘘衰竭的增生。降低晚期转化生长因子-β1活性应能减少细胞外基质沉积和新生内膜 增殖，从而提高动静脉瘘的通畅性。我们将使用我们创新的体内模型，以及一种新颖的 生物反应器和分子工具，来验证我们的假设，具体目的如下： 目的：确定体外转化生长因子-β信号转导和体内动静脉动静脉瘘重构是否存在性别差异。 目的II：确定最佳给药方式，以减少晚期转化生长因子-β1信号，从而增强静脉适应和 提高AVF的通畅性。 目的III：确定Smad2或Tak1功能是否是转化生长因子β1介导的房室结重构的机制。 这项工作将通过确定过度的转化生长因子-β活性是否会导致动静脉瘘而产生持久的影响 失败，以及降低晚期转化生长因子-β活性是否是增强动静脉曲张的有价值的临床翻译策略 通畅性。我们还将确定女性动静脉瘘成熟度降低是否由于静脉供血不足所致。 血管重塑或新生内膜增生增加。我们使用创新的策略和新颖的工具来操纵 转化生长因子-β信号可改变血管壁的成分和强度，从而改善动静脉瘘的通畅性。

Project Summary A cornerstone of several common therapies for human diseases is the use of a vein as a conduit to increase blood flow such as the arteriovenous fistula (AVF), the preferred access for hemodialysis. However, the poor maturation and patency of AVF, especially in women and requiring additional re-do procedures and surgery, reflects our imperfect understanding of the biology of venous remodeling that leads to successful venous adaptation to the arterial environment. This knowledge gap creates an unmet need for novel approaches to enhance venous remodeling and thereby to increase successful clinical use of venous conduits. Successful venous remodeling requires deposition of extracellular matrix (ECM), enabling mechanical strength to resist hemodialysis procedures that puncture the AVF wall with large bore needles 3 times a week. Transforming growth factor (TGF)-β1 regulates numerous cellular functions, including ECM deposition and remodeling. We present exciting new data that: 1) our innovative mouse model of AVF faithfully recapitulates human AVF maturation including an ~1/3 failure rate; 2) female mice with AVF have diminished magnitudes of shear stress compared to male mice; 3) we can manipulate TGF-β1 function in vivo and TGF-β1 is required for successful early AVF remodeling; 4) in failed mouse AVF there is increased ECM, late TGF-β1 expression and smad2/tak1 phosphorylation; 5) there is increased smad2/tak1 phosphorylation in human AVF surgically removed for failure; 6) we developed an innovative nanoparticle tool to manipulate TGF-β1 signaling in vivo. Our data suggest that surgical creation of a fistula stimulates early TGF-β1 activation via smad2/3 and/or tak1 phosphorylation that is critical for successful early venous adaptation and AVF maturation. We hypothesize that exuberant late TGF-β1 activity results in excessive ECM deposition and neointimal hyperplasia causing AVF failure. Reducing late TGF-β1 activity should reduce ECM deposition and neointimal hyperplasia, thereby improving AVF patency. We will use our innovative in vivo model, as well as a novel bioreactor and molecular tools, to test our hypothesis with the following specific aims: Aim I: Determine whether there are sex differences in TGF-β signaling in vitro and AVF remodeling in vivo. Aim II: Determine optimal delivery to reduce late TGF-β1 signaling thereby enhancing venous adaptation and improving AVF patency. Aim III: Determine whether smad2 or tak1 function is a mechanism of TGFβ1-mediated AVF remodeling. This work will have lasting impact by establishing whether excessive TGF-β activity leads to AVF failure, and whether reducing late TGF-β activity is a valuable strategy for clinical translation to enhance AVF patency. We will also determine whether the reduced AVF maturation in women is due to insufficient venous remodeling or increased neointimal hyperplasia. We use an innovative strategy and novel tools to manipulate TGF-β signaling to alter vessel wall composition and strength and thereby improve AVF patency.