Role of Eicosanoids In Modulating Endotoxin Induced Live

在脓毒症相关ARDS的临床环境中，肝衰竭的存在显著增加死亡率，并且动物中内毒素诱导的肺损伤的研究表明对肝脏的影响对于损伤的充分表达是重要的。决定对内毒素的生理反应的生物化学事件的顺序可以是关键转录因子的激活，特别是核因子κ B（NF κ B）和CCAAT增强子结合蛋白β（C/EBP β，又称为NF-IL 6），导致促炎细胞因子的产生。我们的初步数据以及其他数据暗示类花生酸作为这些内毒素作用的调节剂，并且环氧合酶（COX-前列腺素类合成中的近端酶）的诱导也涉及NF κ B和C/EBP β激活。为了阐明与内毒素反应中的肝-肺相互作用相关的生理、生化、分子和病理生理事件之间的关系，我们提出了一系列原位灌注猪模型的研究，在该模型中，肺可以在灌注回路中与或不与肝脏一起灌注。我们将：1）确定内毒素血症对肺血管阻力、肺血管通透性、肺含水量、组织、灌流液和支气管肺泡灌洗液（BALF）中类花生酸和细胞因子的浓度、BALF总细胞计数和分类细胞计数、TNF α、考克斯-1、考克斯- 2和5-脂氧合酶基因的表达的影响，核因子κ B活化肺中的NF κ B和C/EBP β（和肝脏）在灌注回路中包含和不包含肝脏; 2）通过将PGE 2局部控制输注到肺或肝中的任一器官来操纵前列腺素类的浓度，将考克斯抑制剂靶向递送至肝或肺或切除器官与表达考克斯基因的构建体的相互作用，并确定这些相互作用对类二十烷酸产生和内毒素应答的影响; 3）通过部分肝切除、递送p20膜易位信号融合蛋白或用p20基因转染肝或肺来增加肝或肺中的p20（C/EBP β的抑制剂同种型），并确定这些干预对内毒素应答的影响; 4）通过用编码NF κ B活化的反显性抑制剂的基因转染任一器官或施用细胞可渗透的NF κ B抑制性融合蛋白来抑制肝或肺中NF κ B的活化，并确定对内毒素应答的影响。这些研究将把病理生理学与内毒素反应的发病机制联系起来，为确定新的潜在治疗干预提供基础。

In the clinical setting of sepsis related ARDS, the presence of liver failure markedly increases mortality and studies of endotoxin induced lung injury in animals implicate effects on the liver as important for the full expression of the injury. The sequence of biochemical events that dictates the physiologic response to endotoxin may be activation of critical transcription factors, especially nuclear factor kappa B (NFkappaB) and CCAAT enhancer binding protein beta (C/EBPbeta, a.k.a. NF-IL6) in both the lungs and the liver, leading to generation of pro-inflammatory cytokines. Our preliminary data as well as data of others implicate eicosanoids as modulators of these endotoxin effects and induction of the cyclooxygenase (COX-the proximal enzyme in prostanoid synthesis) also involves NFkappaB and C/EBPbeta activation. To elucidate relationships among the physiologic, biochemical, molecular and pathophysiologic events related to liver-lung interactions in the endotoxin response we propose a series of studies in an in situ perfused swine model in which the lungs can be perfused with or without the liver in the perfusion circuit. We will: 1) determine effects of endotoxemia on pulmonary vascular resistance, lung vascular permeability, lung water content, tissue, perfusate and bronchoalveolar lavage fluid (BALF) concentrations of eicosanoids and cytokines, BALF total and differential cell counts, expression of TNFalpha, COX-1, COX- 2 and 5-lipoxygenase genes, activation of nuclear factor kappa B (NFkappaB) and C/EBPbeta in the lungs (and liver) with and without inclusion of the liver in the perfusion circuit; 2) manipulate concentrations of prostanoids in lung or liver by local controlled infusion of PGE2 into either organ, targeted delivery of a COX inhibitor to liver or lungs or transfecting the organ(s) with a construct expressing the COX gene and determine effects of these interactions on generation of eicosanoids and on endotoxin responses; 3) increase p20, the inhibitor isoform of C/EBPbeta, in the liver or the lungs by partial hepatic resection, delivery of a p20 membrane translocation signal fusion protein or transfection of the liver or lungs with a p20 gene and determine effects of these interventions on the endotoxin response; 4) inhibit activation of NFkappaB in liver or lungs by transfection of either organ with a gene encoding a transdominant inhibitor of NFkappaB activation or administration of a cell-permeable NFkappaB inhibitory fusion protein and determine effects on the endotoxin response. These studies will link pathophysiology to pathogenesis of the endotoxin response, providing a basis for identifying new potentially therapeutic interventions.