Increased serum concentrations of visfatin and its production by different joint tissues in patients with osteoarthritis

Background: The goal of this study was to investigate the distribution of visfatin in paired serum and synovial fluid (SF) samples from patients with osteoarthritis (OA), and in serum from healthy controls. In addition, we wished to determine the potential sources of visfatin in joint tissue. Methods: Twenty-three patients with OA requiring total knee arthroplasty (TKA), 17 healthy subjects and ten donors requiring amputation were included in the study. Concentrations of visfatin in serum and SF were analyzed using an enzyme-linked immunosorbent assay (ELISA). The concentration of visfatin was also measured in conditioned media from cultured joint tissues. Results: We found serum visfatin concentrations to be higher in patients with OA compared to healthy controls (p < 0.05), and SF-visfatin concentrations exceeded those in paired serum (p = 0.004). In addition, infrapatellar fat pad and synovium were important sources of visfatin, while osteophytes released largest amounts of visfatin. Therefore, osteophytes can be considered a major source of visfatin in the knee joint in patients with OA. Conclusions: These results suggest that visfatin may be involved in the pathophysiology of OA and may have local effects in the joint during the process of OA. Clin Chem Lab Med 2010;48:1141-5.