Gut-lung axis: Intestinal microbiome and metabolite changes may be linked to COPD, reveals study

You would imagine that your gut health has a huge role to play only in your digestive and metabolic health, but the condition of your gut microbiome affects other aspects of your health too. Recent research has established the existence of a gut-brain axis, which suggests that the intestine and the brain are linked via biochemical pathways. Studies have shown that not only are neurological diseases like Parkinson’s are linked to gut microbiota but so are other aspects of cognitive health and decline. But while the term gut-brain axis is quickly becoming popular, it’s important to remember that there’s also something called the gut-lung axis and imbalances in it can have an immense effect on your health. A study published in Frontiers in Cellular and Infection Microbiology in February 2020 explains that the connections between lung microbiota and gut microbiota form discreet yet complex pathways. The gut-lung axis, in fact, also involves interactions between microbes that have gained entry into the body apart from those within the body. This suggests that the gut-lung axis has a much greater role in shaping immune responses to infections and can potentially interfere in the course of respiratory as well as gastrointestinal diseases. A new study published in Nature Communications suggests that this gut-lung axis comes into play even in patients of chronic obstructive pulmonary disease (COPD). Gut-lung axis in COPD patients COPD is a set of lung diseases that mainly include chronic bronchitis and emphysema. It’s a progressive inflammatory disease with no curative treatment and is currently the third commonest cause of death globally. The new study says that while it’s believed that the lung microbiome contributes to COPD progression, recent research suggests that the lung microbiome does not essentially change in COPD despite reductions in bacterial diversity. On the other hand, many COPD patients also suffer from colitis, indicating that the gut-lung axis may be at play here. The researchers thus hypothesised that changes in the gut environment may contribute to the development and progression of COPD and, in fact, changes in the gut microbiome may be more reliable indicators of COPD. To evaluate the validity of this hypothesis, the researchers analysed stool samples of 28 COPD patients (54 percent of them were female) and 29 healthy participants (66 percent female). The gut microbiome and metabolite profiles of both groups were then compared. The differences in the participants’ age, diet, and smoking habits were also taken into account during the analysis. The researchers found that 146 bacterial species were found to be different between the COPD and healthy groups of participants. COPD patients had an increased level of certain bacteria like Streptococcus sp000187445, Streptococcus vestibularis, and multiple members of the Lachnospiraceae family. These bacteria are associated with reduced lung function. The scientists were also able to identify a particular metabolite signature in the stool samples of COPD patients, which shows a composition of 46% lipid, 20% xenobiotic, and 20% amino acid-related metabolites. The presence of Streptococcus parasanguinis-B was also connected with the presence of COPD-associated metabolites. The study shows that the gut and fecal microbiome of COPD patients not only differs from those of healthy individuals, but certain signatures in fecal metabolites are reliable biomarkers for COPD. The researchers also suggest that understanding the gut-lung axis better — especially how it affects respiratory disease progression — could also provide appropriate avenues for the development of therapies, drugs, and possibly even a cure in the future. For more information, read our article on Chronic obstructive pulmonary disease.  Health articles in Firstpost are written by myUpchar.com, India’s first and biggest resource for verified medical information. At myUpchar, researchers and journalists work with doctors to bring you information on all things health.