CELLULAR MECHANISMS OF PULMONARY ENDOTHELIAL INJURY

肺血管内皮损伤的一般假说 涉及内皮细胞自身对毒性物质的直接反应， 将使用在培养物中生长的内皮细胞测试刺激物， 肺动脉内膜外植体。 内皮反应可包括 细胞内产生有毒氧自由基和产生 花生四烯酸的代谢物。 这些产品可能会改变 内皮层，并影响其与炎性细胞的相互作用。 补体的激活也可能影响免疫系统的直接反应， 内皮细胞对有害刺激的反应及其与 炎症细胞 最后，炎症细胞本身可能会增强 内皮损伤。 为了验证这一假设， 肺动脉内膜内皮层和内皮细胞单层 将通过同位素示踪剂的平衡来测量在培养物中生长的 穿过膜并通过直接测量水力传导率。 干预措施对内皮细胞结构的影响， 将遵循制备，并生产脂氧合酶和 花生四烯酸的环氧合酶产物 将对所造成的伤害进行评估。 各种直接影响 类花生酸对内皮结构、代谢和功能的影响， 确定的问题，将是否一个外源性来源的 花生四烯酸引起了良性的跨内皮细胞的过程， 粒细胞迁移损伤内皮。 测量将 由内毒素和纯化的lip-A对内皮细胞的影响， 结构、代谢和功能。 还将进行测量， 确定内毒素如何改变内皮细胞与 白细胞，以确定是否抗氧化酶传递到细胞 通过脂质体包封改变内皮细胞对内毒素的反应， 以确定是否皮质类固醇，非甾体类药物 和自由基清除剂影响内毒素诱导的损伤。 不同系培养的内皮细胞的敏感性 将检查几种细菌对内毒素的作用， 内毒素诱导的内皮损伤的存在和不存在 将研究白细胞。 拟议的研究结果来自广泛的 在整个动物中获得的结构和功能信息的基础 准备和大量的初步数据表明， 研究的目标是可行的。 这些研究将提供新的 肺血管细胞和体液机制研究进展 并为创新的预防和 弥漫性肺损伤的治疗。

The general hypothesis that injury of pulmonary vascular endothelium involves direct responses of the endothelial cells themselves to toxic stimuli will be tested using endothelial cells grown in culture and explants of pulmonary artery intima. The endothelial responses may include intracellular generation of toxic oxygen radicals and generation of metabolites of arachidonic acid. These products may both alter the endothelial layer and affect its interaction with inflammatory cells. Activation of complement may also affect both the direct response of the endothelial cells to injurious stimuli and their interactions with inflammatory cells. Finally, inflammatory cells, per se, may potentiate the endothelial injury. To test the hypothesis, the barrier function of the endothelial layer of pulmonary artery intima and endothelial monolayers grown in culture will be measured by equilibration of isotopic tracers across the membrane and by direct measurement of hydraulic conductance. The effects of interventions on the structure of endothelial cells in both preparations will be followed and production of both lipoxygenase and cyclooxygenase products of arachidonic acid by endothelium over the course of the induced injury will be evaluated. The direct effects of various eicosanoids on endothelial structure, metabolism and function will be determined as will the question of whether an exogenous source of arachidonic acid causes the otherwise benign process of transendothelial migration of granulocytes to injure the endothelium. Measurements will be made of the effects of endotoxin and purified lipid-A on endothelial structure, metabolism and function. Measurements will also be made to determine how endotoxin alters the interactions of endothelium with leukocytes, to determine whether antioxidant enzymes delivered into cells by liposome encapsulation alter the endothelial response to endotoxin and to determine whether corticosteroids, nonsteroidal antiinflammatory drugs and free radical scavengers affect the endotoxin-induced injury. Susceptibility of different lines of cultured endothelial cells from several species to endotoxin will be examined and the role of complement in endotoxin-induced endothelial injury in the presence and absence of leukocytes will be studied. The proposed studies result from an extensive base of structural and functional information obtained in whole animal preparations and from a large amount of preliminary data suggesting that the goals of the studies are feasible. The studies will provide new information about cellular and humoral mechanisms of pulmonary vascular injury and provide a rationale for innovative approaches for prevention and therapy of diffuse lung injury.