November 6, 2013
Scientists Discover Link Between Bacteria And Arthritis
Lee Rannals for redOrbit.com – Your Universe Online
New findings reported in the journal eLife add evidence that the trillions of microbes in the human body play a major role in regulating health.
Scientists used a sophisticated DNA analysis to compare gut bacteria from fecal samples of patients with rheumatoid arthritis and healthy individuals. The team found that P. copri was more abundant in patients newly diagnosed with rheumatoid arthritis than in healthy individuals or patients with chronic arthritis.
"Studies in rodent models have clearly shown that the intestinal microbiota contribute significantly to the causation of systemic autoimmune diseases," Dan R. Littman, the Helen L. and Martin S. Kimmel Professor of Pathology and Microbiology and a Howard Hughes Medical Institute investigator, said in a press release. "Our own results in mouse studies encouraged us to take a closer look at patients with rheumatoid arthritis, and we found this remarkable and surprising association.”
He said the team couldn’t conclude that there is a causal link between the abundance of P. copri and the onset of rheumatoid arthritis. However, he added they are developing new tools that could hopefully allow scientists to ask if this is the case.
Rheumatoid arthritis is an autoimmune disease that attacks joint tissue and causes painful stiffness and swelling. The condition strikes twice as many women as men and its cause remains unknown, although genetic and environmental factors are thought to help play a role.
"Expansion of P. copri in the intestinal microbiota exacerbates colonic inflammation in mouse models and may offer insight into the systemic autoimmune response seen in rheumatoid arthritis," says Randy S. Longman, a post-doctoral fellow in Dr. Littman's laboratory and a gastroenterologist at Weill-Cornell, said in a press release.
The team said the reason why P. copri growth takes off in newly diagnosed patients with rheumatoid arthritis is unclear. Both diet and genetic factors may play a role in this. However, the researchers also found P. copri extracted from newly diagnosed patients appears genetically distinct from P. copri found in healthy individuals.
The latest researcher shows that treated patients with chronic rheumatoid arthritis carry smaller populations of P. copri.
"It could be that certain treatments help stabilize the balance of bacteria in the gut," Jose U. Scher, director of the Microbiome Center for Rheumatology and Autoimmunity at NYU Langone Medical Center's Hospital for Joint Diseases and an author on the new study, said in a press release. "Or it could be that certain gut bacteria favor inflammation."
The team will now validate their results and investigate whether the gut flora can be used as a biological marker to help guide treatment.
"We want to know if people with certain populations of gut bacteria respond better to certain treatment than others," Dr. Scher said in the release.