Arthritis’s Links to the Gut Microbiome Revealed in New Study

In a breakthrough study shedding light on the intricate connection between gut health and inflammatory diseases, the Inflammatory Arthritis Microbiome Consortium has unveiled important findings. The comprehensive study focused on determining the link between alterations in the gut microbiome and inflammatory arthritis in patients.

Changes in the microbiome

The link between changes in gut bacteria and inflammatory conditions has been previously established in conditions like inflammatory bowel disease. Patients with these conditions show uncommon changes to their microbiomes. Now, researchers are exploring whether these links extend to other chronic immune conditions.

The research, encompassing 440 adults – including 221 diagnosed with rheumatoid arthritis, psoriatic arthritis or ankylosing spondylitis – successfully established a correlation between specific alterations in gut bacteria and the severity of these inflammatory conditions. The patients with inflammatory arthritis showcased an altered gut microbiome composition, characterized by lower levels of beneficial bacteria such as Faecalibacterium prausnitzii and Roseburia intestinalis, and heightened levels of potentially harmful bacteria, including Escherichia coli and Ruminococcus gnavus. These findings reveal a distinct gut microbiome in inflammatory arthritis patients, different from those of healthy individuals.

The microbiome echoes back

The study looked at the functional implications of these alterations to the gut microbiota, noting that the changes impacted the gut’s ability to sequester iron and harvest vitamin B from food. The authors suggest in their paper that these changes could have implications for disease: “Some of these alterations, such as those for B vitamin metabolism, could represent mechanisms for long-term prevention, risk reduction or treatment, as could microbial iron sequestration during arthritis-linked anemia,” they write.

The authors note that their findings cannot establish causation. This is, they write, of particular importance in the gut bacteria–inflammation link, as many of the changes to get bacteria may be in response to alterations to the immune system, rather than the other way around. These changes are so tightly coupled that the authors describe them as a “functional ‘echo’” of each other.

The study has advanced our understanding of the gut microbiome's role in inflammatory arthritis, and the data collected may inform future microbiome-based interventions. However, scientists caution that more research is needed to fully understand the mechanisms that underline this relationship and to develop targeted interventions for improving gut health in patients with these conditions.

Reference: Thompson KN, Bonham KS, Ilott NE et al. Alterations in the gut microbiome implicate key taxa and metabolic pathways across inflammatory arthritis phenotypes. Sci. Trans. Med. 2023: 15; eabn4722. doi: 10.1126/scitranslmed.abn4722