Stress May Reactivate Arthritis via Brown Fat and IL-6

A mouse study from Chiba University traced how psychological stress can bring arthritis back to previously affected joints: the sympathetic nervous system activates brown fat, which releases IL-6, prompting fibroblast-like synoviocytes to produce CXCL1 and recruit neutrophils. Blocking β3-adrenergic receptors or CXCR2 reduced stress-triggered inflammation.

• Stress activates brown fat, which releases IL-6
• IL-6 drives synoviocytes to produce CXCL1 and attract neutrophils
• Blocking β3-adrenergic receptors and CXCR2 reduced joint swelling in mice
• Carriers of the ADRB3 Trp64Arg variant showed a weaker stress link