LIVER LUNG INTERACTIONS DURING GRAM NEGATIVE ENDOTOXEMIA

革兰氏阴性杆菌所致循环性休克与重要器官损伤 菌血症(GNB)是由于细胞因子调节不当引起的 肿瘤坏死因子-α、白细胞介素2的网络 IL-1α、IL-1β、IL-4与粒-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诱导的细胞因子是由 肝和肺可以引发革兰氏阴性败血症休克综合征， 细胞因子在这些器官中表达逃避宿主的机制 监管仍不明朗。缺血-再灌注(I/R)和缺氧- 复氧(H/R)上调细胞因子的生物合成 物种、激活的补体片段(C‘)和α-肾上腺素受体 刺激。这一提议的中心前提是选择性I/R或 GNB下调细胞因子基因后肝、肺的H/R 表达不依赖于这些机制，从而修饰器官 受伤。作为推论，我们认为自动调节性环氧合酶- 缺血组织中衍生二十烷类化合物下调GNB诱导的细胞因子 在后续I/R期间生产，但不是在 缺氧/复氧过程中的氧气输送。拟议研究的目的是测试 假设氧化代谢的变化从低流量I/R与 GNB调节后肝脏和肺的恒流H/R 细胞因子表达的转录调控。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。我们计划改变大肠杆菌的时间 GnB在大鼠肝脏和肺组织中的分级I/R或 H/R细胞因子、一氧化氮合酶和胶原亚型转录本的一系列变化 以Northern分析为特征，就像CO-2的动力学一样。 诱导IL-4、IL-10和转化生长因子-β的抗炎基因。 转录和翻译的影响将通过核来区分 常规化验。相应的蛋白质和前列腺素E2水平将是 在含有和不含有先前二十烷类化合物和黄嘌呤的灌流液中进行分析 氧化酶抑制。在平行研究中，C‘和阿尔法- 肾上腺素能受体的刺激将被确定。这些活动将是 与组织微生物负荷和器官功能的变化相关。 将在培养的Kupffer细胞和肺泡中进行平行研究 巨噬细胞。在清醒动物中，细胞因子介导的肺变化 将分析肝局灶性缺血期间GNB期间的炎症反应 胆汁性肝硬变。这些垂直方向的研究结果将 使整合GNB诱导的决定因素的新合成成为可能 细胞因子的产生和肝、肺的相互作用--在缺血-缺氧过程中 压力。这应该为细胞因子的调节提供新的见解。 革兰氏阴性脓毒症时的表达及其识别机制 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.