Objective. To determine whether apoptosis occurs in rheumatoid arthritis (RA) synoviocytes, and if this phenomenon is dependent on the Fas/Apo‐1 pathway. Methods. Apoptotic change in vivo was examined in RA synovial cells by several standard methods. The ability of cells to undergo Fas‐induced apoptosis was determined in vitro. Results. Typical apoptotic change was demonstrated in RA synovial cells by each method. Anti‐Fas antibody induced apoptotic synovial cell death in vitro. Conclusion. This is the first reported study to demonstrate apoptosis in RA synovial cells. The findings indicate that rheumatoid synoviocytes undergo Fas‐mediated apoptosis.

Objective Body fat is an important source of hormones and cytokines (adipokines) that not only regulate the energy balance, but also regulate the inflammatory and immune responses. This study investigated the association of clinical conditions with serum levels of adipokines in patients with rheumatoid arthritis. Methods Serum levels of resistin, leptin, and adiponectin were measured by enzyme-linked immunosorbent assay in 141 patients (110 women) who fulfilled the 1987 revised criteria of the American Rheumatism Association for the diagnosis of rheumatoid arthritis and in 146 normal controls (124 women). Then the correlations between adipokine levels and clinical parameters were evaluated. Results The serum resistin level did not differ between the patients and controls. However, serum leptin levels were significantly higher in male and female rheumatoid arthritis patients than in the corresponding controls, while the serum adiponectin level was significantly higher in female patients than in female controls. Multivariate analysis revealed that predictors of an elevated resistin level were female sex and Creactive protein (CRP), while the leptin level was related to the body mass index and CRP. Predictors of an elevated adiponectin level were the use of prednisolone and CRP, however, CRP was negatively associated with adiponectin in patients with rheumatoid arthritis. Conclusion The serum levels of resistin and leptin were positively associated with CRP level in patients with rheumatoid arthritis, suggesting that these adipokines may act as pro-inflammatory cytokines in this disease. The serum adiponectin level was elevated in the patients, however, it was negatively associated with CRP level. In addition, the serum levels of resistin, leptin, and adiponectin were also associated with female sex, BMI and the use of prednisolone, respectively.

Objective. To examine whether nuclear factor κB (NF‐κB) is activated in cultured synovial cells in response to tumor necrosis factor α (TNFα) and to investigate the correlation between NF‐κB activation and synovial cell proliferation. Methods. Activation of NF‐κB was detected by electrophoretic mobility shift assay. The transcription of several NF‐κB–dependent genes was evaluated by reverse transcriptase polymerase chain reaction and transient expression assay using human immunodeficiency virus–long terminal repeat chloramphenicol acetyltransferase. Proliferative activity was determined by measurement of 3H‐thymidine incorporation. Results. Stimulation of synovial cells with TNFα activated NF‐κB and subsequent transcription of several genes. Treatment of synovial cells with N‐acetyl‐L‐cysteine (NAC), an antioxidant agent, inhibited TNFα‐induced NF‐κB activation and transcription. Moreover, NAC also inhibited synovial cell proliferation induced by TNFα. Conclusion. Our results suggest that NF‐κB plays a pivotal role in synovial cell activation by TNFα. Thus, suppression of NF‐κB could be a potential therapeutic modality for synovitis such as that of rheumatoid arthritis.

We have recently demonstrated Fas-mediated apoptosis in the synovium of patients with rheumatoid arthritis (RA) and suggested that it may be one factor responsible for the regression of RA.