ALCOHOL'S EFFECTS ON THE DEVELOPING ALVEOLAR MACROPHAGE

描述（由申请人提供）：由于包括肺泡巨噬细胞（AM）在内的炎症细胞不成熟，早产新生儿肺部感染的风险增加。AM是抵抗肺部感染的第一道防线。谷胱甘肽（GSH）是肺中的主要抗氧化剂，AM需要它来维持氧化还原电位和优化细胞内功能。早产儿全身和肺泡谷胱甘肽水平缺乏，使肺部氧化损伤和细胞功能障碍的风险增加。成人长期接触酒精（ETOH）也会增加全身氧化应激，损害AM的免疫功能。育龄妇女的ETOH消费显著增加，仍然是我们社会中的一个重大健康问题。胎儿在子宫内暴露于ETOH有全身性氧化应激的风险，系统性和肝脏GSH降低，活性氧标记物增加就是证据。我们假设，早产引起的肺GSH缺乏在氧化应激（如由子宫内ETOH暴露引起的氧化应激）叠加时加剧。肺中谷胱甘肽的减少减少了常驻AM的谷胱甘肽可用性，从而导致AM功能受损。在一个豚鼠胎儿暴露于ETOH模型中，初步研究表明，ETOH降低了胎儿上皮内膜液中的谷胱甘肽，导致与妊娠对照组相比，AM谷胱甘肽降低。暴露于etoh的AM表现出功能受损、氧化应激增加和细胞凋亡加剧。这是临床相关的，因为它表明，如果暴露于ETOH的慢性氧化应激叠加在早产中，未成熟AM的功能可能会进一步受损。在体内或体外添加GSH前体可以部分恢复AM的功能，减少etoh暴露的AM的凋亡。我们假设慢性子宫内ETOH暴露会消耗肺泡谷胱甘肽，由此产生的慢性氧化应激会损害AM功能，如吞噬和生存能力。此外，我们假设谷胱甘肽补充剂可以减少氧化应激，改善吞噬和生存能力等功能。我们提出了四个具体目标来确定：1)是否在子宫内暴露于ETOH通过增加妊娠期氧化应激和AM凋亡来损害AM功能，2)细胞因子刺激是否进一步损害发育中暴露于ETOH的AM的功能并增加凋亡，3)在体外补充GSH是否恢复ETOH暴露的AM功能并减少凋亡，以及4)体内GSH前体是否在摄取ETOH时保护发育中的AM免受ETOH诱导的功能障碍，氧化应激和凋亡。本提案的结果将确定胎儿暴露于ETOH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.