LIVER-LUNG INTERACTIONS DURING GRAM-NEGATIVE ENDOTOXEMIA

革兰氏阴性菌感染时循环性休克与重要器官损伤 菌血症（GNB）是由细胞因子的不适当调节引起的 肿瘤坏死因子-α（TNF-α）、白细胞介素 （IL）-1 α、IL-1 β、IL 4和粒细胞-巨噬细胞集落刺激 因子（GM-CSF），导致心肺功能障碍和缺血性- 缺氧性细胞损伤虽然GNB诱导细胞因子的产生， 肝和肺可以引发革兰氏阴性脓毒性休克综合征， 这些器官中细胞因子表达逃避宿主的机制 监管仍不明确。缺血再灌注（I/R）和缺氧- 复氧（H/R）由于反应性O2而上调细胞因子的生物合成 种、活化补体片段（C '）和α-肾上腺素受体 刺激.这项建议的核心前提是，选择性I/R或 GNB诱导的肝、肺H/R下调细胞因子基因 表达独立于这些机制，从而修饰器官 损伤作为一个推论，我们提出自动调节环氧合酶- 缺血组织中衍生的类花生酸下调GNB诱导的细胞因子 在随后的I/R期间生产，但在 H/R期间的氧气输送。这项研究的目的是测试 低流量I/R与低流量I/R相比， GNB调节后肝和肺的恒流H/R， 细胞因子表达的转录控制。我们进一步建议， 这种相互作用通过改变一氧化氮合酶来改变组织修复 (NOS)和胶原基因表达。我们计划改变E的时间。杆菌 GNB在离体灌注大鼠肝和肺中的分级I/R或 H/R。细胞因子、NOS和胶原异构体转录物的一系列变化将 其特征在于北方分析，因为将动力学的共- 诱导IL-4、IL-10和TGF-β的抗炎基因。 转录与翻译效应将通过核转录来区分。 连续测定。相应的蛋白质和前列腺素E2水平将 在含有和不含先前的类二十烷酸和黄嘌呤的灌注液中分析 氧化酶抑制在平行研究中，C '和α- 将测定肾上腺素受体刺激。这些事件将 与组织微生物负荷和器官性能的变化相关。 平行研究将在培养的枯否细胞和肺泡 巨噬细胞在清醒的动物中，尼古丁介导的肺变化 将在局灶性肝缺血期间分析GNB期间的炎症， 胆汁性肝硬化这些纵向研究的结果将 使一个新的合成整合GNB诱导的决定因素， 细胞因子的产生与肝-肺相互作用-在缺血-缺氧期间 应力这将为细胞因子的调节提供新的见解， 在革兰氏阴性脓毒症期间表达，同时鉴定 改善急性肺损伤和多器官衰竭的治疗。

Circulatory shock and critical organ injury during gram-negative bacteremia (GNB) result from inappropriate regulation of a cytokine network involving tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1alpha, IL-1beta, IL4, and granulocyte-macrophage colony-stimulating factor (GM-CSF), leading to cardiopulmonary dysfunction and ischemic- hypoxic cellular injury. Although GNB-induced cytokine production by the liver and lungs can initiate the gram-negative septic shock syndrome, the mechanisms by which cytokine expression in these organs escapes host regulation remain unclear. Ischemia-reperfusion (I/R) and hypoxia- reoxygenation (H/R) upregulate cytokine biosynthesis owing to reactive O2 species, activated complement fragments (C'), and alpha-adrenoceptor stimulation. The central premise of this proposal is that selective I/R or H/R of the liver and lungs following GNB downregulates cytokine gene expression independent of these mechanisms, thereby modifying organ injury. As a corollary, we propose that autoregulatory cyclooxygenase- derived eicosanoids in ischemic tissues downregulate GNB-induced cytokine production during subsequent I/R, but not during equivalent reductions in O2 delivery during H/R. The objective of the proposed research is to test the HYPOTHESIS that changes in oxidative metabolism from low-flow I/R vs. constant-flow H/R of the liver and lungs following GNB modulate post- transcriptional control of cytokine expression. We further propose that such interactions modify tissue repair by altering nitric oxide synthase (NOS) and collagen gene expression. We plan to vary the timing of E. coli GNB in ex situ perfused rat liver and lungs with respect to graded I/R or H/R. Serial changes in cytokine, NOS and collagen isoform transcripts will be characterized by Northern analyses, as will the kinetics of the co- induced anti-inflammatory genes for IL-4, IL-10, and TGF-beta. Transcriptional vs. translational effects will be distinguished by nuclear run-on assays. Corresponding protein and prostaglandin E2 levels will be analyzed in perfusates with and without prior eicosanoid and xanthine oxidase inhibition. In parallel studies, the effects of C' and alpha- adrenoceptor stimulation will be determined. These events will be correlated with changes in tissue microbial burden and organ performance. Parallel studies will be performed in cultured Kupffer cells and alveolar macrophages. In conscious animals, cytokine-mediated changes in lung inflammation during GNB will be analyzed during focal hepatic ischemia and biliary cirrhosis. Results from these vertically-oriented studies will enable a new synthesis integrating the determinants of GNB-induced cytokine production and liver lung interactions-during ischemic-hypoxic stress. This should provide novel insights into the regulation of cytokine expression during gram negative sepsis while identifying mechanistic therapies to ameliorate acute lung injury and multiple organ failure.