The Multiple Roles of Lysyl Oxidase in Arteriovenous Fistula Failure

赖氨酰氧化酶在动静脉内瘘衰竭中的多重作用

• 批准号: 10454770
• 负责人: Roberto Irenardo Vazquez Padron
• 金额: --
• 依托单位: MIAMI VA HEALTH CARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10454770
• 关键词: Address; Animal Model; Area; Arteriovenous fistula; Atomic Force Microscopy; Biochemistry; Biology; Biomechanics; Blood; Blood Vessels; Blood flow; Cell Nucleus; Cells; Chronic Kidney Failure; Collagen; Complication; Copper; Data; Deamination; Dialysis procedure; Elastin; Enrollment; Epigenetic Process; Experimental Animal Model; Extracellular Matrix; Extracellular Space; Failure; Fibrosis; Fistula; Functional disorder; Gene Expression; Gene Silencing; Generations; Genes; Genetic Transcription; Goals; Hemodialysis; Histone Code; Histones; Hospitalization; Human; Hyperplasia; In Situ; In Vitro; Intervention; Knockout Mice; Label; Limb structure; Location; Manuscripts; Mass Spectrum Analysis; Medial; Mediating; Microscopy; Modeling; Morbidity - disease rate; Mus; Myography; Nuclear; Nucleosomes; Operative Surgical Procedures; Outcome; Outcome Study; Pathogenicity; Pathologic; Patients; Pharmacology; Phenotype; Postoperative Period; Process; Protein-Lysine 6-Oxidase; Proteomics; Publishing; Quality of life; Research; Risk; Role; Secure; Smooth Muscle Myocytes; Source; Stenosis; Techniques; Testing; Thick; Time; Up-Regulation; Vascular remodeling; Veins; Venous; Veterans; amine oxidase; biobank; catalyst; cell type; chromatin immunoprecipitation; cohort; conditional knockout; cost; crosslink; design; extracellular; improved; medical complication; mortality; neointima formation; new therapeutic target; novel; novel therapeutics; preservation; pressure; prevent; promoter; response; second harmonic; targeted treatment; vascular contributions

More than 14 000 enrolled veterans depend on an arteriovenous (A-V) fistula or other type of vascular access to receive hemodialysis and prolong their lives. The transformation of a vein to a fistula is one of the most intriguing processes in vascular biology. The desired scenario is that the fistula matures becoming a larger vessel with increased luminal area and a thicker wall. Unfortunately, A-V fistulas frequently fail (~40%) because venous stenosis compromises blood flow. We recently discovered that stenosis occurs due to excessive medial fibrosis, and is aggravated by intimal hyperplasia (IH). Our specific goal is to demonstrate that up-regulated lysyl oxidase (LOX) in the venous limb of the A-V fistula mediates improper extracellular matrix (ECM) remodeling and pathological expansion of the intima, which causes stenosis and failure. This proposal establishes the cause- effect relationship among LOX and fistula outcomes in order to design targeted therapies. 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 remodeling that causes fistula failure. Specifically, we hypothesize that LOX disrupts the epigenetic marks that secure contractile gene expression in smooth muscle cells (SMC), thereby facilitating the phenotypic switch of SMCs, neointima formation, and fibrosis of newly created A-V fistulas. We also postulate that extracellular LOX simultaneously increases stiffness and altered collagen configuration in this type of vascular access. We will test our hypothesis in three specific aims and five experimental layouts that will prove: 1) the contribution of vascular LOX to postoperative A-V fistula stenosis; 2) the role of LOX in the epigenetic control of the SMC phenotype after fistula creation; and 3) the relationship between pre- existing LOX and A-V fistula outcomes in a human cohort. We will use fine microsurgical techniques in a novel conditional knockout mice and in vitro and in situ models to successfully achieve our goals. We will also interrogate a human biorepository of >300 patients undergoing creation of a two- stage brachiobasilic transposition fistula to search for associations between the levels of LOX and maturation 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.

超过 14,000 名入伍退伍军人依靠动静脉 (A-V) 瘘管或其他类型的血管 获得血液透析并延长生命。静脉向瘘管的转变是其中之一 血管生物学中最有趣的过程。理想的情况是瘘管成熟成为 更大的血管，具有更大的管腔面积和更厚的壁。不幸的是，动静脉瘘经常失败（~40%） 因为静脉狭窄会影响血流。我们最近发现狭窄的发生是由于 过度的内侧纤维化，并因内膜增生（IH）而加剧。我们的具体目标是展示 A-V 瘘静脉肢中赖氨酰氧化酶 (LOX) 的上调介导了不适当的细胞外 基质（ECM）重塑和内膜病理性扩张，导致狭窄和衰竭。这 提案建立了 LOX 和瘘管结果之间的因果关系，以便设计 靶向治疗。我们的建议建立在强有力的科学前提（手稿和独特的初步 数据）表明术后自体瘘中 LOX 上调之间存在机制关系 以及导致瘘管失败的不当重塑。具体来说，我们假设 LOX 会破坏 表观遗传标记可确保平滑肌细胞 (SMC) 中的收缩基因表达，从而促进 平滑肌细胞 (SMC) 的表型转换、新内膜形成和新形成的 A-V 瘘管的纤维化。我们也 假设细胞外液氧同时增加硬度并改变胶原蛋白的构型 血管通路的类型。我们将在三个具体目标和五个实验布局中检验我们的假设 这将证明：1）血管LOX对术后A-V瘘狭窄的贡献； 2）LOX的作用 瘘管形成后 SMC 表型的表观遗传控制； 3）预之间的关系 人类队列中现有的 LOX 和 A-V 瘘结果。我们将使用精细的显微外科技术 新型条件敲除小鼠以及体外和原位模型成功实现了我们的目标。我们将 还询问了超过 300 名患者的人类生物储存库，这些患者正在创建两阶段臂轴 转位瘘管以寻找 LOX 水平与成熟失败之间的关联。在 结论，随着该提案的成功完成，我们正在为设计铺平道路 新药物和细胞类型特异性干预措施可有效针对 A-V 瘘纤维化并减少血管 访问并发症。