Clinical Trial andIn VitroStudy for the Role of Cartilage and Synovia in Acute Articular Infection

Abstract

Objective. Osteoarthritis is a long-term complication of acute articular infections. However, the roles of cartilage and synovia in this process are not yet fully understood.Methods. Patients with acute joint infections were enrolled in a prospective clinical trial and the cytokine composition of effusions compared in patients with arthroplasty (n= 8) or with intact joints (n= 67). Cytokines and cell function were also analyzed using a humanin vitromodel of joint infection.Results. Synovial IL-1βlevels were significantly higher in patients with arthroplasty (p= 0.004). Higher IL-1βconcentrations were also found in thein vitromodel without chondrocytes (p< 0.05). The anti-inflammatory cytokines IL-4 and IL-10 were consistently expressedin vivoandin vitro, showing no association with the presence of cartilage or chondrocytes. In contrast, FasL levels increased steadilyin vitro, reaching higher levels without chondrocytes (p< 0.05). Likewise, the viability of synovial fibroblasts (SFB) during infection was higher in the presence of chondrocytes. The cartilage-metabolism markers aggrecan and bFGF were at higher concentrations in intact joints, but also synthesized by SFB.Conclusions. Our data suggest an anti-inflammatory effect of cartilage associated with the SFBs’ increased resistance to infections, which displayed the ability to effectively synthesize cartilage metabolites.The trial is registered with DRKS00003536, MISSinG.