iNOS gene therapy to prevent AV graft intimal hyperplasia

一氧化氮(NO)介导血管平滑肌细胞(SMC)的松弛，抑制血小板和白细胞的黏附，阻止SMC的增殖。全身性不给药可能与低血压等不良反应有关。我们认为，通过使用腺病毒基因治疗技术局部传递NO将局部增加NO的产生，并避免全身毒性。这种应用的理想基因是诱导型一氧化氮合酶(INOS)亚型，它能产生高水平的NO独立钙通量。与其他异构体相比，iNOS的酶活性较高，可能产生更大的临床疗效，但基因转移效率较低。我们已经建立了腺病毒介导的诱导型一氧化氮合酶基因导入血管损伤的动物模型，显着减少了血管内膜的增生。有了这些令人鼓舞的临床前结果，iNOS基因治疗已经准备好在人类疾病中进行评估。评估这种疗法的一个有吸引力的临床模型是在血液透析(HD)患者中放置的动静脉(AV)移植物。移植物的静脉吻合口极易发生侵袭性的内膜增生，其发生率或程度远远超过血管成形术或搭桥手术。继发于内膜增生的房室移植失败是一种经济负担，也是HD患者发病率的一个来源。房室移植失败是研究iNOS基因治疗的安全可行的模型。目的：在一项I期临床试验中，评估腺病毒介导的诱导型一氧化氮合酶(INOS)基因转移到接受动静脉曲张移植物植入HD的患者的安全性。我们将进行剂量递增研究，以确定在AIM II中使用的最高和最安全的腺病毒载体剂量。患者将受到密切关注，以寻找使用iNOS的腺病毒载体出现全身或局部不良反应的证据。目的：在一项II期临床试验中，以移植物功能和通畅性为指标，确定iNOS基因转移抑制植入HD的动静脉移植物内膜增生的效果。在常规血液透析过程中进行的非侵入性双功成像和静脉阻力测量将允许监测移植物功能，而不会对患者造成额外风险。评估的结果是移植物的一次通畅率、二次通畅率和移植物翻修次数。这项临床研究的信息将决定iNOS基因治疗的疗效。如果有益，这种疗法将应用于其他原因的内膜增生症，如血管成形术和外周及冠状动脉搭桥术。

Nitric oxide (NO) mediates vascular smooth muscle cell (SMC) relaxation, inhibits platelet and leukocyte adhesion, and prevents SMC proliferation. Systemic NO administration may be associated with adverse effects such as hypotension. We propose that local NO delivery through the use of adenoviral gene therapy techniques will locally augment NO production and avoid systemic toxicity. The ideal gene for this application is the inducible NO synthase (iNOS) isoform which produces high levels of NO independent calcium fluxes. The greater enzymatic activity of iNOS as compared with the other isoforms may yield greater clinical efficacy with lower gene transfer efficiency. We have already established the adenovirus mediated iNOS gene deliver to animal models of vascular injury dramatically reduced intimal hyperplasia. With these encouraging preclinical results, iNOS gene therapy is ready to be evaluated in human disease. An attractive clinical model in which to evaluate this therapy is in arteriovenous (AV) grafts placed in hemodialysis (HD) patients. The venous anastomoses of AV grafts are extremely prone to an aggressive form of intimal hyperplasia that far exceeds the incidence or extent seen in angioplasty or bypass surgery. AV graft failure secondary to intimal hyperplasia is a financial burden and is also a source of morbidity among patients on HD. AV graft failure is a safe and feasible model in which to study iNOS gene therapy. AIM I: To assess the safety of adenovirus mediated iNOS gene transfer into patients undergoing AV graft placement for HD access in a Phase I clinical trial. We will perform dose escalation studies to determine the highest and safest dose of adenoviral vector to use in Aim II. Patients will be closely followed for evidence of adverse systemic or local reactions to adenoviral vector of iNOS administration. AIM II: To determine the efficacy of iNOS gene transfer for the inhibition of intimal hyperplasia in AV grafts placed for HD as measured by graft function and patency in a Phase II clinical trial. Non-invasive duplex imaging and venous resistance measurements made during routine HD will allow graft function to be monitored with no additional risk to the patient. The outcomes that will be assessed are primary graft patency, secondary patency, and number of graft revisions. The information from this clinical study will determine the efficacy of iNOS gene therapy. If beneficial, this therapy will be applied to other etiologies of intimal hyperplasia such as following angioplasty and peripheral and coronary bypass.