Is Rheumatoid Arthritis Triggered by Gut Bacteria?

What does your gut have to do with neck pain? New research suggests a link between Rheumatoid Arthritis and bacteria in the digestive tract. Could gut flora be an environmental trigger for patients with a genetic predisposition for the autoimmune joint disease? Mayo Clinic researchers seem to think so.

Risk of RA Connected to Bacteria in the Gut

Immunologist Veena Taneja, PhD, and colleagues at the Mayo Clinic and University of Illinois, published a paper in the April 2012 edition of PloS One offering an explanation for what causes Rheumatoid Arthritis (RA). Their paper provides the first real demonstration that genes controlling the immune system and bacteria in the gut interact to affect a person’s likelihood of developing RA. Such findings could lead to a test of gut flora as a useful tool in studies for RA, acting as an early warning sign in effect for patients deemed high risk for developing the painful joint disease.

Autoimmunity and Rheumatoid Arthritis Diagnosis

Rheumatoid arthritis can cause painful and swollen joints, lead to degeneration of the spine and subsequent instability and neck pain, as well as causing symptoms such as fever, malaise, and fatigue. There is no current biomarker for the disease which can lead to patients being incorrectly diagnosed; thus allowing joint degeneration to go unchecked and suffering to continue. This latest study adds to evidence that the gut plays a major role in immune system regulation with dysfunction of this system triggering RA and other autoimmune diseases seemingly unconnected to the gastrointestinal system.

Gut Bacteria Differ in Arthritis-Resistant Mice

The research by Taneja, et al, used transgenic mice with human leukocyte antigen (HLA) mutations that made them either more susceptible to Rheumatoid Arthritis or resistant to arthritis. They then tested to gut flora of these mice to see if they could predict subsequent arthritis development. The *401 mice (susceptible to arthritis) had a high level of Clostridium-like bacteria in the gut whereas the *0402 (arthritis-resistant) mice had more beneficial bacteria such as Bifidobacteria and Porphyromonadaceae species.

Friendly Bacteria and Inflammation

Bifidobacteria have been associated with an anti-inflammatory response in both the gut itself and the peripheral immune system through a variety of mechanisms such as: inhibition of T-cell proliferation; reduction of pro-inflammatory cytokines; and inhibition of nuclear factor kappa B activation. Patients with Rheumatoid Arthritis may develop spinal abnormalities after chronic inflammation in the joints; this may then lead to
disc degeneration, facet joint disease, cervical spinal stenosis, and neck pain, along with degeneration of other joints such as the knees, ankles, and in the hands.

Gut Permeability, Immunity, and RA

The mice that were more susceptible to RA has altered gut permeability, suggesting that larger molecules could more easily enter systemic circulation unchecked where they trigger an immune system response. Mice resistant to RA had dynamically different gut flora influenced by the sex and age of the mice whereas these factors made seemingly no difference in the arthritis-susceptible mice. This study does not suggest that swallowing large volumes of so-called ‘friendly bacteria’ can stave off Rheumatoid arthritis. Instead, the research demonstrates that the bacterial populations in the gut are likely influenced by the genetic environment provided by the host.

Supplements and Diet for Rheumatoid Arthritis?

Food and environmental factors do affect the bacteria in the gut, however, and it may be that better bacteria in the gut can reduce RA symptoms or even partially protect against it developing in susceptible individuals. Taneja, et al, do say as much in their paper but acknowledge that more research would need doing to investigate such a hypothesis. Patients with suspected RA may find themselves, in the future, having a test of gut bacteria biomarkers and maybe even being given a prescription for probiotics rather than anti-inflammatories or steroids as treatment for Rheumatoid Arthritis. Commentators have questioned the data presented in this study, largely due to the nature of the statistical methods used and their presentation. It is unlikely, therefore, that many doctors will recommend friendly bacteria for Rheumatoid Arthritis patients or suggest dietary changes for RA and neck pain on the basis of this study alone.

References

Gomez, A., Luckey, D., Taneja, V., et al, (2012), Loss of Sex and Age Driven Differences in the Gut Microbiome Characterize Arthritis-Susceptible *0401 Mice but Not Arthritis-Resistant *0402 Mice, PloS ONE. 2012.