Objective To examine
osteopontin (OPN) levels in both
synovial fluid and
articular cartilage of
patients with primary
knee osteoarthritis (OA) and to investigate their relationship with severity of the
disease.
Methods Fifty
patients with
knee OA and 10 healthy controls were enrolled in this study.There were 15
males and 35
females with an average age of 61.8±7.4 years in OA group. The
control group included 4
males and 6
females with an average age of 63.2±6.0 years. Mankin score were taken to determine the
disease severity of the affected
knee. The radiographic grading of OA in the
knee was performed using the Kellgren-Lawrence criteria. OPN levels in
synovial fluid were measured using
enzyme-linked immunosorbent assay. OPN levels in
articular cartilage were assessed by immunohistochemical
methods. Results Compared to healthy controls, the
knee OA
patients had higher OPN concentration in
synovial fluid ([4519.60±1830.37] pg/ml vs. [1179.70±303.39] pg/ml) and
articular cartilage([0.60±0.06] vs. [0.43 ±0.07]). In addition,
synovial fluid OPN levels showed a positive correlation with
articular cartilage OPN levels (r=0.411,P=0.003). Subsequent
analysis showed that the OPN levels in
synovial fluid significantly had been correlated with severity of
disease using Kellgren-Lawrence criteria (r=0.581, P< 0.001). Furthermore,the levels of OPN in the
articular cartilage also were correlated with
disease severity using Mankin score (r=0.675, P< 0.001).Conclusion The data suggest that OPN in
synovial fluid and
articular cartilage is related to progressive
joint damage and could be a predictive
biomarker respect to
disease severity and progression in
knee OA.