The microbiota and arthritis: correlations or cause?

Purpose of review: The microorganisms that colonise our bodies, the commensal ‘microbiota’, respond to changes in our behaviour and environment, and can also profoundly affect our health. We can now investigate these organisms with unprecedented depth and precision, revealing that they may contribute to the pathogenesis of diseases including arthritis. Here we discuss the changes occurring in the microbiota in people with arthritis, and how manipulation of the microbiota may provide an additional pathway for therapy. Recent findings: We highlight two important aspects of the recent literature. First we describe changes in the microbiota identified in people with arthritis; these correlations give insights into the microbial changes that may contribute to symptoms of arthritis. We then discuss attempts to ameliorate arthritis by manipulating the microbiota. This is a rapidly developing area of research. There are tantalising hints that interventions targeting the microbiota may become therapeutically viable for some types of inflammatory arthritis. Summary: Our commensal microbial communities respond to changes in our health, and are altered in people with arthritis. Understanding the complex relationships between the microbiota and the body may enable us to deliberately manipulate these organisms and provide additional therapeutic options for people with arthritis