Pathogenesis of Aspiration Pneumonitis

描述(申请人提供)：胃抽吸是发生急性肺损伤(ALI)和ARDS的主要危险因素。这项建议研究了增加吸入相关病理风险的细胞机制。尽管许多宿主的变化尚不清楚，但我们先前的工作已经证明了肿瘤坏死因子α、IL-1U、IL-6、IL-10、CXC趋化因子、单核细胞趋化蛋白-1和毒性炎症产物在吸入性ALI发病机制中的作用。我们还证明了胃材料中的低pH分泌物协同增加了随后的损伤(即小食物颗粒)后ALI的急性严重性和可持续性。AIM 1将利用药物诱导的肺泡巨噬细胞(AM0)耗竭和重建、转基因(基因缺失和过度表达)小鼠和流式细胞术的策略，详细研究驻留和招募aM0的作用，以及肺泡上皮细胞(AEC)在酸和小颗粒(CASP)诱导的严重ALI的发病机制中的作用。我们假设，CASP组分对aM0和AEC反应的相互作用导致了协同的、持续的ALI，加速了aM0的凋亡/坏死，并在细胞因子表达谱改变的情况下招募了新的M0群体。此外，还将评估Fas/FasL系统和募集的白细胞凋亡在CASP ALI发病机制中的作用。目的2将研究炎症转化的特定介质的作用，包括利用转基因小鼠或缺陷型腺病毒载体重组IL-6、IL-10、单核细胞趋化蛋白-1、肿瘤坏死因子α或过表达这些细胞因子的研究，或通过使用抗细胞因子抗体或基因缺失小鼠的研究。我们预测，肿瘤坏死因子α诱导的IL-6、IL-10和/或MCP-1细胞因子在胃吸入后从急性炎症反应向不那么强烈的炎症反应的转变中发挥重要作用。在最终目标中，我们将使用一种蛋白质组学方法，利用一种新的多重微阵列ELISA技术来识别局部和系统的生物标记物和aM0表型，以比较患者和小鼠的反应，以提供对吸入性ALI的病因和发病机制的机械性见解，并为测试治疗策略提供理论基础。此外，这将为开发诊断和预后生物标记物提供试点数据，以区分吸入事件和细菌性肺炎。

DESCRIPTION (provided by applicant): Gastric aspiration is a major risk factor for the development of acute lung injury (ALI) and ARDS. This proposal examines cellular mechanisms that increase the risk of aspiration-associated pathology. Although many host changes are poorly understood, our prior work has demonstrated a role forTNFalpha, IL-1U, IL- 6, IL-10, CXC chemokines, MCP-1, and toxic inflammatory products in the pathogenesis of aspiration- induced ALI. We have also demonstrated that low pH secretions in the gastric material synergistically increase the acute severity and sustainability of ALI following a subsequent insult (i.e., small food particles) Aim 1 will utilize drug-induced alveolar macrophage (aM0) depletion and reconstitution, transgenic (gene deletion and over-expression) mice, and flow cytometric strategies to examine in detail the role resident and recruited aM0, and alveolar epithelial cells (AEC) play in the pathogenesis of the severe ALI induced by combined acid and small particles (CASP). We hypothesize that the interaction of the components of CASP on aM0 and AEC responses leads to a synergistic, sustained ALI with accelerated aM0 apoptosis/necrosis and recruitment of a new M0 population with altered cytokine expression profiles. The role of the Fas/FasL system and apoptosis of recruited leukocytes in the pathogenesis of CASP ALI will also be assessed. Aim 2 will examine the roles of specific mediators of the inflammatory transition, including studies using recombinant IL-6, IL-10, MCP-1, TNFalpha, or over expression of these cytokines with transgenic mice or defective adenovirus vectors, or by employing anti-cytokine antibodies or gene deletion mice. We predict that TNFalpha-induced IL-6, IL-10, and/or MCP-1 cytokines play an important role in the transition from an acute to a less intense inflammatory response following gastric aspiration. In the final aim, we will employ a proteomic approach utilizing a novel multiplex microarray ELISA technology to identify local and systemic biomarkers and aM0 phenotypes to compare responses in patients and mice in order to provide mechanistic insight into the etiology and pathogenesis of aspiration-induced ALI and provide a rationale on which to test therapeutic strategies. Additionally, this will provide pilot data for developing diagnostic and prognostic biomarkers to differentiate aspiration events from bacterial pneumonia.