Associations between knee structural measures, circulating inflammatory factors and MMP13 in patients with knee osteoarthritis

Summary Objective To investigate cross-sectional associations between serum level of Matrix metalloproteinase (MMP)13 and knee structural measures and circulating inflammatory factors in patients with symptomatic knee osteoarthritis (OA). Design A total of 149 subjects with symptomatic knee OA were included. Magnetic resonance imaging was used to measure infrapatellar fat pad (IPFP) volume, IPFP signal intensity alternation, cartilage volume and cartilage defects. Knee radiography was used to assess radiographic OA using the Kellgren-Lawrence (K-L) grading system. Enzyme-linked immunosorbent assay was used to measure the serum levels of inflammatory factors and MMP13. Results In multivariable analyses, serum MMP13 was negatively associated with cartilage volume at patellar site (β: −32.94 mm 3 per 10 ng/ml, P P P 3 per 10 ng/ml, P P P Conclusions Serum level of MMP13 was associated with knee structural abnormalities as well as serum inflammatory factors. These suggest that systemic MMP13 may play a role in knee OA, and could be regulated by inflammatory factors.