Chulalongkorn Medical Journal


Background : Osteoarthritis (OA) is characterized by the progressive loss of articularcartilage and osteophyte formation resulting in pain, stiffness, reducedmotion, swelling, crepitus, and disability. The aim of this study is toinvestigate plasma and synovial fluid matrix metalloproteinase-1 (MMP-1)levels of patients with primary knee OA and to examine their relationshipwith disease severity.Methods : Thirty-two patients aged 53 - 83 years old with knee OA and 10 healthyindividuals were recruited into this study. Disease severity was determinedusing weight-bearing anteroposterior radiographs of the affected knee.The radiological grading of knee OA was performed according to Kellgren-Lawrence grading system. MMP-1 levels in both plasma and synovial fluidwere evaluated using enzyme-linked immunosorbent assay.Results : The mean plasma MMP-1 levels were higher in OA patients compared tocontrols; however, the difference was not statistically significant (198.0 ± 63.5 vs. 94.2 ± 2.4 pg/ml, P = 0.1). MMP-1 levels in synovial fluid of OApatients (2632.8 ± 525.2 pg/ml) were 13-fold higher than in correspondingblood samples (P <0.001), and were 26-fold higher than in the plasma ofhealthy controls (P <0.001). Subsequent analysis revealed that synovialfluid MMP-1 levels of knee OA patients were positively correlated with OAgrading (r = 0.873, P< 0.001).Conclusions : MMP-1 levels in synovial fluid are positively associated with the severity ofjoint damage in knee OA. Synovial fluid MMP-1 may serve as a biomarkerfor determining disease severity and could play a possible role inthe pathogenesis of osteoarthritis.


Faculty of Medicine, Chulalongkorn University

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