ALCOHOL'S EFFECTS ON THE DEVELOPING ALVEOLAR MACROPHAGE

描述(申请人提供)：由于包括肺泡巨噬细胞(AM)在内的炎性细胞的不成熟，早产儿肺部感染的风险增加。AM是抵御肺部感染的第一道防线。谷胱甘肽(GSH)是肺中的一种主要抗氧化剂，AM需要它来维持氧化还原电位和优化细胞内功能。早产儿全身和肺泡GSH水平不足，使肺处于氧化损伤和细胞功能障碍的风险增加。成人长期接触酒精也会增加全身氧化应激，损害AM的免疫功能乙醇消费量在育龄妇女中显著增加，在我们的社会中仍然是一个重大的健康问题。胎儿在宫内暴露于乙醇会有全身氧化应激的风险，表现为全身和肝脏GSH降低，而活性氧类标记物增加。我们推测，早产所致的肺GSH缺乏症在叠加氧化应激时会加重，如宫内乙醇暴露所致。肺中GSH的减少降低了常驻AM的GSH利用率，从而导致AM功能受损。在胎儿乙醇暴露的豚鼠模型中，初步研究表明，与妊娠匹配的对照组相比，乙醇降低了胎儿上皮衬里液体中的GSH，导致AM GSH降低。乙醇暴露的AM表现出功能受损，氧化应激增加，细胞凋亡加剧。这在临床上是相关的，因为它表明，如果乙醇暴露的慢性氧化应激叠加在早产上，未成熟AM的功能可能会进一步受损。体内或体外添加GSH前体可部分恢复乙醇暴露的AM功能并减少细胞凋亡我们假设，子宫内慢性乙醇暴露会耗尽肺泡GSH，由此产生的慢性氧化应激会损害AM的吞噬功能和生存能力。此外，我们假设GSH补充剂将减少乙醇受损AM中的氧化应激，并改善吞噬功能和生存能力。我们提出了四个特定的目标来确定：1)子宫内乙醇暴露是否通过增加妊娠期间的氧化应激和AM细胞凋亡来损害AM的功能，2)细胞因子刺激是否进一步损害了发育中的Etoh暴露的AM的功能并增加了细胞凋亡，3)体外补充GSH是否恢复了Etoh暴露的AM的功能并减少了细胞凋亡，以及4)体内GSH前体在摄入Etoh的过程中是否能保护发育中的AM免受Etoh诱导的功能障碍、氧化应激和细胞凋亡的影响。这项建议的结果将确定胎儿乙醇暴露对肺内发育中的AM的新影响，为优化早产儿这些细胞功能的潜在临床策略提供新的见解。

DESCRIPTION (provided by applicant): Premature newborns are at increased risk of pulmonary infection due to the immaturity of inflammatory cells including the alveolar macrophage (AM). The AM is the first line of defense against infection in the lung. Glutathione, (GSH) a major antioxidant in the lung, is required by the AM to maintain redox potential and optimize intracellular functioning. Levels of systemic and alveolar GSH are deficient in the premature newborn, placing the lung at increased risk for oxidant injury and cellular dysfunction. Chronic alcohol (ETOH) exposure to adults also increases systemic oxidative stress and impairs the immune function of the AM. ETOH consumption has increased significantly in women of childbearing age and remains a significant health problem in our society. The fetus exposed to ETOH in utero is at risk for systemic oxidant stress, as evidenced by decreased systemic and hepatic GSH, and increased markers of reactive oxygen species. We postulate that the pulmonary GSH deficiency caused by prematurity is exacerbated when superimposed on oxidant stress, such as that caused by in utero ETOH exposure. Decreased GSH in the lung decreases GSH availability for the resident AM, thereby contributing to impaired AM function. In a guinea pig model af fetal ETOH exposure, preliminary studies showed that ETOH decreased GSH in the fetal epithelial lining fluid, resulting in decreased AM GSH compared to gestationally matched controls. The ETOH-exposed AM demonstrated impaired functions, increased oxidative stress, and accentuated apoptosis. This is clinically relevant because it suggested that the functions of the immature AM may be further impaired if the chronic oxidative stress of ETOH exposure is superimposed on premature delivery. The addition of GSH precursors in vivo or in vitro partially restored AM function and reduced apoptosis of ETOH-exposed AM. We hypothesize that chronic in utero ETOH exposure depletes alveolar GSH and the resultant chronic oxidative stress impairs AM functions such as phagocytosis and viability. Furthermore, we hypothesize GSH supplements will decrease oxidative stress in the ETOH-impaired AM and improve functions such as phagocytosis and viability. We propose Four Specific Aims to determine: 1) if in utero ETOH exposure impairs AM function by increasing oxidative stress and AM apoptosis across gestation, 2) if cytokine stimulation further impairs function and increases apoptosis of the developing ETOH-exposed AM, 3) if in vitro GSH supplementation restores ETOH-exposed AM functions and reduces apoptosis, and 4) if in vivo GSH precursors, administered during ETOH ingestion, protect the developing AM from ETOH induced dysfunction, oxidative stress and apoptosis. Results from this proposal will identify novel effects of fetal ETOH exposure on the developing AM within the lung, providing new insight on potential clinical strategies to optimize the function of these cells in the premature newborn.