Chiba University researchers link stress to rheumatoid arthritis flares

Researchers at Chiba University in Japan have identified a biological mechanism explaining how psychological stress can trigger flares of rheumatoid arthritis, even when the disease is in remission. The study, published in Science Advances, utilized mouse models to trace the pathway from emotional distress to joint inflammation.

The findings reveal that stress activates the sympathetic nervous system, which in turn stimulates brown adipose tissue (a type of fat responsible for heat production). This activation causes the tissue to release interleukin-6 (IL-6), a potent inflammatory signaling protein. Once in the bloodstream, IL-6 stimulates fibroblast-like synoviocytes in the joints to produce CXCL1, which subsequently recruits neutrophils to the site, leading to joint swelling.

This discovery suggests that the impact of stress on autoimmune diseases extends beyond traditional immune cells and involves other bodily tissues. The research team included specialists from Asahi General Hospital and the International University of Health and Welfare Narita Hospital.