气道微生态失衡在支气管扩张患者中的作用及阿奇霉素干预的影响

Bronchiectasis is a common chronic airway disease for diverse aetiology, associated with the vicious cycle involving "infection-inflammation-airway destruction' in which bacteria play a pivotal role. Our previous studies have observed a high prevalence of bacterial isolation (about 60%) in patients with steady-state bronchiectasis based on culture-dependent methods, and it has been associated with increased sytemic and airway inflammation, worse quality of life, more frequent exacerbations and poor prognosis. However, the culture-dependent methods has only applied to limited bacterial genera and yielded poor accuracy, which precluded the understanding of the complexity of airway microrgnism as a whole in bronchiectasis. The aim of our study was to characterize the airway microbial community using metagenomic techniques and PCR-based method in paitents with idiopathic, post-infectious bronchiectasis and healthy controls; and to investigate the gene expression profiles of airway epithelial cells with RNA-Seq and the associated cytokines with Bio-Plex Pro Human Cytokine 27-Plex Assay from bronchoalveolar lavage fluid (BALF) in patients with bronchiectasis. Additionally, we would like to elucidate the alterations of bacterial composition and diversity in BALF, and to determine whether the gene expression profiles of airway epithelial cells and the associated cytokines in BALF will be changed after 12-month use of azithromycin, and to assess the relationship between these changes and reduced bronchiectasis exacerbations. Our study might help us to comprehensively realize the role of airway microbiota on the pathogenesis of bronchiectasis and the potential impacts of therapeutic interventions, and shed light on the physiopathologic mechanisms of bronchiectasis from the view of microbiota, which will lay the foundation for manupulating the airway microbiota to improve patients' prognosis.

支气管扩张（简称支扩）是一种常见的、病因异质的慢性气道疾病，细菌感染→气道炎症→气道破坏构成的“恶性循环”是其发病的中心环节，其中细菌感染又起着突出作用。我们前期及国外的研究均发现稳定期支扩气道细菌分离比例可达60%，并与系统和气道炎症、生活质量、急性加重及预后密切相关。然而上述依赖纯培养的方法仅能对少部分细菌进行分离培养且准确性低，无法从整体上了解气道菌群紊乱对支扩发生发展的影响。本研究拟采用宏基因组学和PCR的方法深度分析稳定期支扩气道微生物群落的丰度和多样性；利用RNA-Seq和蛋白悬液芯片研究微生物菌群对气道局部基因和细胞因子表达的影响；并观察12个月阿奇霉素治疗对气道微生物菌群结构及局部基因和蛋白表达的影响，及其与治疗反应的相关性。期望全面了解气道微生物群落菌群在支扩发生发展中的作用及可能的干预影响，从微生态的视角揭示支扩的发生机制，为将来依赖气道微生态调节治疗支扩提供理论依据。

（1）支气管扩张是一种气道慢性炎症性疾病，这种气道炎症可通过“渗漏”的方式导致全身炎症水平的增加，进而导致全身血管功能的异常，引发心血管疾病。队列研究发现，支气管扩张患者心血管风险明显增加。我们募集稳定期支气管扩张病人，采用超声的方法检测颈动脉内-中膜的厚度、内皮舒张功能，同时通过测定肱踝脉搏波传导速度，使用ELISA的方法检测全身炎症因子水平。我们的研究发现：支气管扩张患者血流介导的舒张功能减退，同时肱踝脉搏波传导速度增加，并与疾病的严重程度及铜绿假单胞菌的定植成正相关，但是与系统炎症水平无关；同时，支气管扩张患者颈动脉内-中膜的厚度未见明显变化。我们的研究提示，通过筛查血流介导的舒张功能及肱踝脉搏波传导速度评估支气管扩张患者早期心血管受损情况具有一定的临床意义。.（2）铜绿假单胞菌是支气管扩张患者最长分离出的细菌，并且常发生耐药。然而耐药铜绿假单胞菌对于支气管扩张患者的临床意义并不清楚。我们收集就诊于郑州大学第一附属医院的支扩患者，通过痰培养的方法明确是否合并铜绿假单胞菌感染，以及耐药的情况，并对这些患者进行前瞻性随访，探讨对于患者预后的意义。我们的研究发现，19.7%的支气管扩张患者合并铜绿假单胞菌感染，耐药的发生率约为59.9%（至少对一种敏感的抗铜绿假单胞菌药物耐药）。合并耐药铜绿假单胞菌感染的危险因素包括：先前的抗生素暴露，3次或以上的急性加重，mMRC呼吸困难评分较高及影像学支扩严重程度。然而合并耐药铜绿假单胞菌感染并不影响患者的预后。.（3）单侧支气管扩张患者健侧和患侧的微生态可能并不相同，进而引起的宿主基因表达有差异。我们试图通过募集稳定期单侧支气管扩张，通过防污染鞘管获取健侧和患侧的肺泡灌洗液，同时通过防污染毛刷进行上皮细胞刷检。目前共募集稳定期单侧支气管扩张患者9人，健康对照者10人。相关的测序工作正在进行。