Interesting association between intestinal bacteria and rheumatoid arthritis

Prevotella copri, a species of intestinal bacteria is considered a possible trigger for rheumatoid arthritis ( RA), according to a study led by researchers at New York University School of Medicine. The study published in  the journal  eLife demonstrates that this inflammatory joint disease may be mediated by specific intestinal bacteria. The researchers reached this conclusion after comparing samples of gut bacteria from healthy patients and from patients with rheumatoid arthritis and found that P. Co is more common in the latter.

Dan R. Littman, MD, PhD, the Helen L. and Martin S. Kimmel Professor of Pathology and Microbiology and the Howard Hughes Medical Institute investigator, said that studies in rodents have clearly demonstrated that intestinal microbiota contribute to the onset of this autoimmune systemic disease. He added that the findings led them to look more carefully in patients with rheumatoid arthritis and found this surprising association. However, Dr. Littman explained that considering the current studies, we cannot conclude yet that between P. Copri and rheumatoid arthritis is a causal relationship.

The present study is based on the results of a previous research conducted by Dr. Littman in collaboration with researchers at Harvard Medical School. They found that mice genetically predisposed to the disease do not develop RA if they are kept in a sterile environment, however, when exposed to benign gut bacteria, the mice begin to show signs of joint inflammation. Rheumatoid arthritis is an autoimmune disease characterized by joint inflammation, pain and stiffness . The causes of this disease are not clearly known even if there have been put into question certain environmental and genetic factors etc.

Statistics show that about 1.3 million Americans suffer from rheumatoid arthritis; it seems that this disease affects twice as many women than men. In addition to affecting the joints, rheumatoid arthritis may cause other symptoms and signs such as lung damage, skin lesions, etc.  It is a debilitating disease that has no cure although there are several classes of drugs that are used in rheumatoid arthritis such as antibiotics, antiinflammatory drugs, immunosuppressive drugs etc . Although it is not known how these drugs affect the microbiota, it seems that patients with chronic rheumatoid arthritis treated have lower populations of P. copra.

Randy S. Longman, MD, PhD, a postdoctoral fellow in Dr. Littman ‘s laboratory and a gastroenterologist at Weill – Cornell, said that the expansion of P. Copri exacerbates colonic inflammation; however how this expansion affects the immune response in rheumatoid arthritis still remains a mystery.