Dual Role of Lysyl Oxidase in Arteriovenous Fistula Failure

血液透析动静脉（A-V）内瘘的失败是通过手术建立的， 将静脉与附近的动脉缝合仍然是血管外科领域中未解决的医学问题。 手术事实上，大约十分之四的新瘘管需要手术或 血管内挽救手术以达到成熟并适合于血液透析。 动静脉瘘失败，因为狭窄（血管狭窄）阻止高血 流经静脉分支并增加血栓形成的风险。我们最近 发现狭窄是由于过度的中膜纤维化和增加 细胞外蛋白交联，并通过人内膜增生（IH）加重 共165名患者。因此，我们的总体目标是，第一，建立 脂氧合酶是最重要的酶， 第二，设计新的治疗方法，以促进A-V 通过血管周围递送LOX抑制剂使瘘管成熟。我们的建议是建立在强大的 科学前提（手稿和独特的初步数据），表明一个机械的 自体瘘管中LOX的术后上调与不适当的 导致瘘管衰竭的血管壁重塑具体来说，我们的首要假设是 LOX活性是动静脉瘘成熟失败的主要原因。我们的主要假设 手术后核LOX的上调使组蛋白中的赖氨酸残基脱氨基， 表观遗传景观，确保SMC中收缩基因的表达，从而促进 它们的适应不良表型转换、新生内膜形成和新创建的动静脉纤维化 瘘管我们的第二个假设是LOX的抑制阻止了内向重塑 在猪的临床前动静脉瘘模型中。我们将在三个方面来检验我们的假设 具体目标：1）确定动静脉瘘形成后LOX的细胞来源，2） 证明LOX介导的组蛋白修饰对瘘后SMC表型的影响 创建和 3)证明LOX抑制剂可减弱临床前A-V中的向内重塑、IH和狭窄， 猪的瘘管我们将使用精细的显微外科技术， 基因敲除小鼠以及体外和原位模型，以成功实现我们的目标。我们 还将使用猪的临床前模型来证明 LOX抑制剂在预防动静脉瘘失败中的血管周围递送。总之，随着 这项提案的成功完成，我们正在为新药的设计铺平道路， 细胞类型特异性干预，以有效靶向动静脉瘘纤维化， 入路并发症。

The failure of hemodialysis arteriovenous (A-V) fistulas, which are surgically created by anastomosing a vein to a nearby artery, remains an unmet medical problem in the field of vascular surgery. In fact, approximately four out of 10 newly created fistulas will require a surgical or intravascular salvage procedure to reach maturation and become suitable for hemodialysis. Arteriovenous fistulas fail because stenosis (vascular narrowing) prevents high blood flows through the venous limb and increases the risk for thrombosis. We recently discovered that stenosis occurs due to excessive medial fibrosis and increased extracellular protein crosslinking, and is aggravated by intimal hyperplasia (IH) in a human cohort of 165 patients. Therefore, our overall goals are, first, to establish the cause-and-effect relationship between LOX, the most important enzyme responsible for crosslinking, and A-V fistula failure and, second, to design new therapeutics to facilitate A-V fistula maturation through perivascular delivery of LOX inhibitors. Our proposal is built on strong scientific premises (manuscripts and unique preliminary data) that suggest a mechanistic relationship between postoperative upregulation of LOX in native fistulas and the improper wall remodeling that causes fistula failure. Specifically, our overarching hypothesis is that LOX activity is a major contributor in A-V fistula maturation failure. Our primary hypothesis is that postsurgical upregulation of nuclear LOX deaminates lysine residues in histones to disrupt the epigenetic landscape that secures contractile gene expression in SMCs, thereby facilitating their maladaptive phenotypic switch, neointima formation, and fibrosis of newly created A-V fistulas. Our secondary hypothesis is that inhibition of LOX prevents inward remodeling in a preclinical A-V fistula model in swine. We will test our hypothesis in three specific aims that will: 1) identify the cellular source of LOX after A-V fistula creation, 2) demonstrate the impact of LOX mediated histone modifications on the SMC phenotype after fistula creation, and 3) demonstrate that LOX inhibitors attenuate inward remodeling, IH, and stenosis in preclinical A-V fistulas in swine. We will use fine microsurgical techniques in novel conditional knockout mice and in vitro and in situ models to successfully achieve our goals. We will also use a preclinical model in swine to demonstrate the efficacy and safety of perivascular delivery of LOX inhibitors in preventing A-V fistula failure. In conclusion, with the successful accomplishment of this proposal, we are paving the way for the design of new drugs and cell type-specific interventions to effectively target A-V fistula fibrosis and reduce vascular access complications.