COPD severity and gut microbiota. Comprehensive profiling of the gut microbiota in patients with chronic obstructive pulmonary disease of varying severity

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disease that reduces lung and respiratory function, with a high mortality rate. Severe and acute deterioration of COPD can easily lead to respiratory failure, resulting in personal, social, and medical burden. Recent studies have shown a high correlation between the gut microbiota and lung inflammation. In this study, we investigated the relationship between gut microbiota and COPD severity. A total of 60 COPD patients with varying severity according to GOLD guidelines were enrolled in this study. DNA was extracted from patients’ stool and 16S rRNA data analysis conducted using high-throughput sequencing followed by bioinformatics analysis. The richness of the gut microbiota was not associated with COPD severity. The gut microbiome is more similar in stage 1 and 2 COPD than stage 3+4 COPD. Fusobacterium and Aerococcus were more abundant in stage 3+4 COPD. Ruminococcaceae NK4A214 group and Lachnoclostridium were less abundant in stage 2-4, and Tyzzerella 4 and Dialister were less abundant in stage 1. However, the abundance of a Bacteroides was associated with blood eosinophils and lung function. This study suggests that no distinctive gut microbiota pattern is associated with the severity of COPD. The gut microbiome could affect COPD by gut inflammation shaping the host immune system.

慢性阻塞性肺疾病（Chronic obstructive pulmonary disease, COPD）是一类损害肺脏与呼吸功能的慢性呼吸系统疾病，病死率较高。重症及急性加重期COPD极易引发呼吸衰竭，进而给个人、社会及医疗系统带来沉重负担。近期研究表明，肠道菌群与肺部炎症存在高度相关性。本研究旨在探讨肠道菌群与COPD病情严重程度之间的关联。本研究共纳入60名依据全球慢性阻塞性肺疾病防治创议（Global Initiative for Chronic Obstructive Lung Disease, GOLD）指南划分病情严重程度的COPD患者。研究人员从患者粪便样本中提取DNA，通过高通量测序技术完成16S rRNA数据分析，并辅以生物信息学手段开展后续分析。结果显示，肠道菌群的丰富度与COPD病情严重程度并无显著关联。与3+4期COPD患者相比，1期与2期COPD患者的肠道菌群组成更为相似。3+4期COPD患者体内的梭杆菌属（Fusobacterium）与气球菌属（Aerococcus）丰度更高；2-4期COPD患者中，瘤胃球菌科NK4A214群（Ruminococcaceae NK4A214 group）与毛螺菌属（Lachnoclostridium）的丰度更低；而1期COPD患者体内的Tyzzerella 4属与Dialister属丰度亦较低。不过，某一拟杆菌属（Bacteroides）物种的丰度与血液嗜酸性粒细胞水平及肺功能指标存在显著关联。本研究提示，尚未发现与COPD病情严重程度相关的特异性肠道菌群特征。肠道菌群或可通过调控肠道炎症、塑造宿主免疫系统，进而对COPD的发生发展产生影响。