Mechanisms of Bacterial Induced Lung Injury

细菌引起的肺损伤的机制

• 批准号: 6820192
• 负责人: Jeanine P Wiener-Kronish
• 金额: $ 28.17万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-30 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6820192
• 关键词: Pseudomonas aeruginosa; adult respiratory distress syndrome; bacterial genetics; bacterial pneumonia; bacterial proteins; bactericidal immunity; diagnostic respiratory lavage; genetic strain; genetic susceptibility; human subject; iatrogenic disease; laboratory mouse; lectin; lung injury; patient oriented research; positive pressure breathing; proteomics; respirators; virulence

Pneumonia is the most common cause of sepsis and the most common cause of acute lung injury (ALI). The overall objective of this project is to investigate the contribution of human genetic abnormalities and bacterial virulence genes to the development of clinical lung injury and pneumonia. We have chosen a specific human genetic abnormality and a group of bacterial virulence genes (type III secretion system) to investigate because of their potential importance in lung infections, particularly lung infections in critically ill patients, and in patients at risk for ALI. Mannose binding lectin (MBL) deficiency is one of the most common immunodeficiencies and has been associated with severe lung disease due to mucosally-acquired pathogens. P.aeruginosa is the most frequent Gram negative pathogen associated with ventilator-associated pneumonia (VAP). The products of Type III secretion system genes in P.aeruginosa cause acute lung injury in experimental animals and P.aeruginosa strains isolated from critically ill patients produce type III secretion proteins. We will establish a prospective cohort investigation to test the hypothesis that genetic abnormalities in MBL are associated with an increased risk of severe ALI (Aim 1). We will also establish a prospective cohort investigation of the molecular characteristics of P.aeruginosa strains and the genetic expression of virulence genes in ventilated patients who are colonized with P.aeruginosa (Aim 2). Patients with P. aeruginosa colonization (established by surveillance cultures of tracheal aspirates) will undergo periodic BAL to determine whether colonization can be distinguished from VAP by a biochemical marker of lung epithelial injury. BAL will also be done on patients with VAP and/or ALI due to P.aeruginosa; the results of these BAL fluids will be compared to the BAL obtained from colonized patients. This aim will test the hypothesis that transformation from colonization to lung infection is associated with the expression of the Type III secretion virulence genes. We will then compare the P.aeruginosa strains obtained from patients with VAP and/or ALI to the strains obtained from patients who are only colonized with P.aeruginosa and quantify the lung injury caused by the airspace instillation of the strains into mice (Aim 3). This final aim will allow us to utilize animals to answer a clinical question; whether the colonizing strains and the strains found in patients with VAP differ in terms of their biologic effects. BAL fluids from patients and from the mice will be utilized in other projects (l&3) to evaluate the procoagulant pathway and the antifibrinolytic pathway in the distal airspaces. The fluids will also be evaluated in the proteomics core to determine whether bacterial virulence proteins can be measured in BAL fluids from patients with VAP and/or ALI and whether markers of epithelial injury can also be found in the BAL fluids of these patients.

肺炎是败血症的最常见原因，也是急性肺损伤 (ALI) 的最常见原因。该项目的总体目标是研究人类遗传异常和细菌毒力基因对临床肺损伤和肺炎发展的贡献。我们选择了一种特定的人类遗传异常和一组细菌毒力基因（III 型分泌系统）进行研究，因为它们在肺部感染中的潜在重要性，特别是危重患者和有 ALI 风险的患者的肺部感染。甘露糖结合凝集素（MBL）缺乏是最常见的免疫缺陷之一，与粘膜获得性病原体引起的严重肺部疾病有关。铜绿假单胞菌是与呼吸机相关性肺炎相关的最常见的革兰氏阴性病原体 （VAP）。铜绿假单胞菌中的III型分泌系统基因产物可引起实验动物的急性肺损伤，从危重患者中分离出的铜绿假单胞菌菌株可产生III型分泌蛋白。我们将建立一项前瞻性队列研究来检验 MBL 基因异常与严重 ALI 风险增加相关的假设（目标 1）。我们还将针对铜绿假单胞菌菌株的分子特征以及铜绿假单胞菌定植的通气患者毒力基因的基因表达进行前瞻性队列研究（目标 2）。铜绿假单胞菌定植的患者（通过气管抽吸物的监测培养确定）将定期接受 BAL，以确定是否可以通过肺上皮损伤的生化标志物将定植与 VAP 区分开来。 BAL 还将对因铜绿假单胞菌引起的 VAP 和/或 ALI 患者进行 BAL；这些 BAL 液体的结果将与从定植患者获得的 BAL 进行比较。这个目标将考验 假设从定植到肺部感染的转化与 III 型分泌毒力基因的表达有关。然后，我们将从 VAP 和/或 ALI 患者获得的铜绿假单胞菌菌株与仅定植有铜绿假单胞菌的患者获得的菌株进行比较，并量化将菌株空腔滴注到小鼠体内所造成的肺损伤（目标 3） ）。最终目标将使我们能够利用动物来回答临床问题；定植菌株和 VAP 患者体内发现的菌株在生物学效应方面是否有所不同。来自患者和小鼠的 BAL 液体将用于其他项目 (l&3)，以评估促凝血途径和抗纤维蛋白溶解途径 远端空域。这些液体还将在蛋白质组学核心中进行评估，以确定是否可以在 VAP 和/或 ALI 患者的 BAL 液体中测量细菌毒力蛋白，以及是否也可以在这些患者的 BAL 液体中发现上皮损伤标记物。