High adiponectin and adipoR1 expression levels were found in the synovial fluids and tissues of patients with rheumatoid arthritis [36], and adiponectin has also been shown to stimulate prostaglandin E2 (PGE2) production in the synovial fibroblasts of individuals with rheumatoid arthritis [37]. Here, ADIPOR1 is linked to rheumatoid arthritis.