Nitric Oxide in Chronic Renal Disease

描述(申请人摘要)：有相当多的间接证据 在各种病因的慢性肾脏疾病(CRD)中，有净 肾脏和可能的全身性一氧化氮(NO)缺乏，可能 有助于肾脏疾病的进展和继发性 高血压。一个可能对减少NO做出重要贡献的因素 合成(NOS)是内源性一氧化氮合酶抑制物ADMA的积累。我们 提出一系列全面的研究，在老鼠身上，这将建立 年内NO系统不同方面的相对贡献 肾功能衰竭的演变。这些研究将包括对 ADMA的代谢。将使用两种不同的CRD模型，其中一种 (肾质量减少5/6)将在严重和不严重的情况下使用 系统性高血压。我们将使用体内功能研究来研究 清醒大鼠的肾功能和血压调节 调节肾小球和外周微循环，使用 麻醉制剂。大多数研究将在Spraogue Dawley大鼠身上进行，但 此外，还将研究哪些老鼠对CRD(Dahl盐)敏感 敏感大鼠)和抵抗CRD(Wistar-Furth大鼠)，以确定 基线一氧化氮合酶活性与慢性阻塞性肺疾病易感性有关。此外，新陈代谢 CAGE和体外研究将在不同的小鼠身上进行，目标是 一种或多种一氧化氮合酶的缺失。在老鼠身上，干预措施将是 用于改善(L-精氨酸补充；血管紧张素抑制) 或加剧(低剂量一氧化氮合酶抑制，尿素补充)进展 将对其对NOS系统的影响进行评估。采集的大鼠血浆 将在体外与培养的内皮细胞进行生物测试，以确定其 对一氧化氮合酶活性的影响，基于我们的临床观察表明 CRD患者血浆中可能含有一氧化氮合酶抑制因子。细胞培养研究也将 尿毒症患者尿毒症抑制L-精氨酸的机制探讨(S) 运输。总体而言，这些研究将使我们能够检验假设1) 在慢性阻塞性肺疾病期间，由于一系列的原因，NO产量逐渐下降 一氧化氮合酶系统的改变，包括内源性激素水平的增加 抑制剂。2)一旦确定，疾病的病因就无关紧要了 对于这种渐进性的无功能丧失3)严重程度和比率 慢性阻塞性肺疾病的发生部分取决于一氧化氮合酶活性的初始水平， 4)尿毒症水平的尿素通过还原底物影响NO的产生 可用性。

DESCRIPTION (Applicant's abstract): There is considerable indirect evidence that in established chronic renal disease (CRD) of various causes, there is net renal and possibly systemic nitric oxide (NO) deficiency which probably contributes to both the progression of the renal disease and to the secondary hypertension. One factor which may make an important contribution to reduced NO synthesis (NOS) is accumulation of the endogenous NOS inhibitor ADMA. We propose a comprehensive series of studies, in rats, which will establish the relative contributions of different aspects of the NO system during the evolution of renal failure. These studies will include an investigation into the metabolism of ADMA. Two distinct models of CRD will be used, one of which (the 5/6th reduction of renal mass) will be employed with, and without, severe systemic hypertension. We will use in vivo functional studies to investigate renal function and blood pressure regulation in the conscious rat as well as regulation of the glomerular and peripheral microcirculation, using anesthetized preparations. Most studies will be in the Sprague Dawley rat, but in addition, rats will be studied who are susceptible to CRD (Dahl salt sensitive rats) and resistant to CRD (Wistar-Furth rats), to determine whether baseline NOS activity is related to the CRD susceptibility. Further, metabolic cage and in vitro studies will be conducted in various mice with targeted deletions of one or more of the NOS enzymes. In rats, interventions will be used to either ameliorate (L-arginine supplementation; angiotensin inhibition) or exacerbate (low dose NOS inhibition, urea supplementation) progression of CRD, and their impact on the NOS system will be evaluated. Harvested rat plasma will be bioassayed in vitro with cultured endothelial cells to determine its impact on NOS activity, based on our clinical observations which suggest that CRD plasma may contain NOS inhibitory elements. Cell culture studies will also explore the mechanism(s) by which uremic levels of urea inhibit L-arginine transport. These studies will, in aggregate, allow us to test the hypotheses 1) That NO production decreases progressively during CRD due to a series of alterations in the NOS system including increased levels of endogenous inhibitors. 2) That once established, the etiology of the disease is irrelevant to this progressive loss of NO function 3) That the severity and rate of development of CRD is determined in part by the initial level of NOS activity, 4) That uremic levels of urea impact on NO production via reducing substrate availability.