Ruan G, et al. - Experts evaluated cross-sectional relationships between serum level of MMP13 and knee structural measures and circulating inflammatory factors in patients with symptomatic knee osteoarthritis (OA). Findings suggested an association of serum level of MMP13 with knee structural abnormalities as well as serum inflammatory factors. In knee OA, systemic MMP13 could play a role. It could be regulated by inflammatory factors. Authors noted negative association of serum level of adiponectin with serum MMP13 quartiles and serum levels of TNF-α and a positive association of IL-8 and IL-18 with serum MMP13 quartiles.