Prof Phil Hansbro

People with COPD have a unique gut microbiome signature that may provide a useful biomarker for the disease and also have potential for treatment targeting, Australian researchers say.

A study led by scientists from the University of Queensland found significant variation in the faecal microbiome and metabolome of COPD patients and healthy controls, with 146 bacterial species differing between the two groups.

The comparison of faecal samples from 28 COPD patients and 29 healthy control subjects also found that several species found more commonly in people with COPD correlated with reduced lung function, including Streptococcus sp000187445, Streptococcus vestibularis and multiple members of the family Lachnospiraceae.

Using metabolomics, the researchers identified a COPD signature comprising 46% lipid, 20% xenobiotic and 20% amino acid related metabolites.

Analysis of the faecal micriobiota also revealed a link between Streptococcus parasanguinis_B and COPD-associated depletion of amino acid metabolites such as N-acetylglutamate and its analogue N-carbamoylglutamate.

The study, published in Nature Communications, found no difference in microbiome composition between smokers and non-smokers with COPD, “supporting this as a disease-associated phenotype rather than one driven by the influence of cigarette smoke on the gut microbiome,” the researchers said.

“Several elements of the newly described COPD gut metabolome suggest altered systemic metabolism associated with the disease, the outcomes of which are detectable in faecal samples promoting faecal sampling as a means of monitoring disease,” the study authors wrote.

“Since changes in metagenomes correlated with disease features, the processes involved may have the potential to be therapeutic targets or the outputs used as faecal biomarkers, although this would need clinical and experimental validation.”

“This suggests that stool sampling and analysis could be used to non-invasively diagnose and monitor for COPD,” concluded the study authors, led by Dr Kate Bowerman of the Australian Centre for Ecogenomic, University of Queensland

The authors said the ‘gut-lung axis’ may also be important in the development and treatment of COPD.

“It’s already known that the lung microbiome is a contributing factor in COPD,” said Professor Phil Hansbro, senior author of the study and Director of the Centenary UTS Centre for Inflammation, Sydney.

“Our COPD findings suggest that the gut microbiome should now also be considered when looking for new therapeutic targets to help treat lung disease,” he added.