Gut bacteria have a say in rheumatoid arthritis

New research suggests that rheumatoid arthritis (RA), a chronic autoimmune disease targeting the joints and resulting in painful inflammation, has a correlation with the bacteria that live in our intestines. The finding, published in the online science journal eLife, specifically relates the onset of RA to the bacterium Prevotella copri.

When comparing intestinal bacteria from the fecal samples of healthy patients versus those with new-onset RA, scientists from the New York University school of medicine discovered that P. copri was far more prevalent in patients who had been diagnosed with the initial stages of RA. As expected, healthy individuals had a lesser amount of P. copri in their feces. Those who had been treated for chronic RA were also found to have significantly smaller amounts of the intestinal bacterium. Another interesting fact was that the increased prevalence of P. copri was associated with a decreased amount of the beneficial gut bacteria Bacteroides. When the bacterial ecosystem is altered in this way, there is great potential for the immune system to start malfunctioning.

“Studies in rodent models have clearly shown that the intestinal microbiota contribute significantly to the causation of systemic autoimmune diseases,” said Dan R. Littman, the study”s corresponding author., “At this stage, however, we cannot conclude that there is a causal link between the abundance of P. copri and the onset of rheumatoid arthritis. We are developing new tools that will hopefully allow us to ask if this is indeed the case.”

Current treatments for RA include antibiotics, anti-inflammatory drugs such as steroids, and immunosuppressive therapies, all of which target just the symptoms. It is unclear how these treatments affect the microbial environment of our intestines. However, it has been made evident that the population of P. copri in the gut of patients with chronic RA who have been treated with these medications is much smaller than in new-onset RA patients.

Because of this revelation, novel treatments for RA will be looking at targeting to reduce the superfluous growth of P. copri in the gut, thereby potentially delaying or preventing the onset of RA. The scientists are planning to expand the study and look at populations outside of New York. This is because microbial populations within the human gut can vary by geographical region. They will be looking at whether or not variations in gut bacteria may lead to variations in patient treatment success. The scientists are planning further investigation in people prior to their development of RA to determine whether the relationship between P. copri and RA is one of cause or effect.