New evidence linking gut bacteria with rheumatoid arthritis development
A study published in the journal Arthritis & Rheumatology has provided new evidence gut bacteria plays a role in the development of rheumatoid arthritis. The research suggests an abnormal immune response to a relatively common species of gut bacteria could influence the development of arthritis.
Rheumatoid arthritis is widely considered to be a multifactorial disease. This means no single gene or environmental exposure is solely responsible for its development. Instead, a constellation of factors are likely needed to trigger the autoimmune behavior associated with the disease.
A growing body of evidence points to the gut microbiome playing a role of the priming of the disease. In fact, one specific bacterial strain has been the focus of much research over recent years.
Prevotella copri is not generally considered to be a harmful strain of gut bacteria. It can be found in most people's microbiome and has even been linked to high-fiber, low-fat diets. But over the last decade some research has found associations between rheumatoid arthritis and abnormal levels of Prevotella copri.
This new study looked specifically at blood levels of an immune antibody generated to target a specific protein expressed by Prevotella copri. Not only were the researchers interested in whether people with pre-existing rheumatoid arthritis were showing an excessive immune response to this particular bacterial protein, but they looked at groups of people in the earliest stages of disease, and groups classified at a high risk of developing the disease.
The analytic technique revealed those with rheumatoid arthritis did show higher levels of antibodies compared to healthy controls. But more significantly, those at a high risk of the disease also showed higher levels of the antibodies compared to the control. And, suggesting a possible causal relationship, those with established rheumatoid arthritis showed higher levels of antibodies compared to those in the earliest stages of the disease.
Of course, this evidence is far from definitive, and serious questions remain. While there may be a correlation between increased immune activity against this bacterial protein and rheumatoid arthritis, it doesn't necessarily mean this relationship drives disease progression.
Nevertheless, a 2017 study has already hypothesized how this particular Prevotella copri protein could plausibly trigger autoimmune activity that leads to arthritic inflammation. But this is still incredibly speculative and Jennifer Seifert, corresponding author on the new research, said more work is warranted by these findings to better understand any potential relationship between gut bacteria and rheumatoid arthritis (RA).
“Our hope is that these findings can help to further elucidate the complex etiologic role of bacterial commensals in people who are at-risk of developing RA and in those with RA so that targeted therapies can be developed with the goals of providing better treatment and ultimately, prevention of the disease,” said Seifert.
The new study was published in Arthritis & Rheumatology.