Elevated Circulating and Synovial Fluid Endoglin Are Associated with Primary Knee Osteoarthritis Severity
Received 16 April 2009; accepted 10 July 2009.
Background and Aims
Osteoarthritis (OA) is a chronic degenerative joint disorder of the synovial joint characterized by loss of articular cartilage, osteophyte formation, and alterations of subchondral bone. The aim of this study was to evaluate endoglin levels in both plasma and synovial fluid of patients with primary knee OA and to determine their relationship with disease severity.
Methods
Thirty nine patients with primary knee OA and 15 healthy controls were recruited in this study. The radiographic grading of OA in the knee was performed using the Kellgren and Lawrence classification. Endoglin concentrations in both plasma and synovial fluid were analyzed using a sandwich enzyme-linked immunosorbent assay.
Results
The average value of plasma endoglin in patients with knee OA was significantly higher compared with that of healthy controls (5.16±0.22 vs. 4.43±0.3 ng/mL, p=0.03). Although endoglin levels in synovial fluid were higher with respect to paired plasma samples, the difference was not significant (5.41±0.32 vs. 5.16±0.22 ng/mL, p=0.3). Additionally, plasma endoglin levels exhibited a positive correlation with synovial fluid endoglin levels (r=0.52, p=0.001). Further analysis revealed that plasma endoglin levels significantly correlated with disease severity (r=0.38, p=0.02). Furthermore, the synovial fluid levels of endoglin also positively correlated with disease severity (r=0.55, p=0.001).
Conclusions
These findings indicate that endoglin in plasma and synovial fluid is correlated with progressive joint damage in knee OA. Endoglin is likely to be useful as a biomarker for determining disease severity and may play a possible role in the pathogenesis of osteoarthritis.
aDepartment of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
bDepartment of Orthopaedics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
Address reprint request to: Sittisak Honsawek, M.D., Ph.D., Department of Biochemistry and Orthopaedics, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Rama IV road, Patumwan, Bangkok 10330, Thailand; Phone: +662-256-4482; FAX: +662-256-4482
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