To correlate plasma osteopontin level with radiological grade in patients with
knee osteoarthritis (OA) and to correlate plasma osteopontin level with serum
hyaluronic acid in patients with knee OA, thereby to assess, if osteopontin contributes
to the pathogenesis of the degenerative process of OA by stimulating MMP13 and
increase hyaluronic acid levels in serum.
Materials and methods:
60 patients with varying grades of radiological evidence of OA in the knee
joint and 30 healthy subjects as controls were enrolled in the study. Anteroposterior
knee radiographs, in standing position were taken to determine the disease severity of
the affected knee joint. The radiographic grading of OA in the knee joint was
performed by using the Kellgren–Lawrence grading (K/L). Osteopontin levels in the
plasma and hyaluronic acid levels in the serum were measured using enzyme-linked
immunosorbent assay and compared.
Results:
The mean plasma osteopontin concentration of the knee OA patients was
significantly higher compared with that of healthy controls (984.91+/-804 pg/mL vs
611.05+/-207.59 pg/mL, p=0.014). The plasma osteopontin levels significantly
correlated with severity of disease (r=0.349, p=0.006). The mean serum hyaluronic
acid concentration of the knee OA patients was significantly higher compared with
that of healthy controls (2.58+/−0.90ng/mL vs 1.87+/−0.48 ng/mL). The serum
hyaluronic acid level significantly correlated with K/L grades (r=0.358, p=0.005). The
plasma osteopontin and serum hyaluronic acid levels were compared in relation to
radiological K/L grades 2, 3, 4 among the cases and was found to have statistically
significant higher concentrations as the grade increased with p= 0.022 for osteopontin
and p=0.006 for hyaluronic acid.
Conclusion:
Osteopontin in plasma and Hyaluronic acid in serum are related to progressive
joint damage in knee OA. Hence in the present study statistically significant increase
in concentration of both osteopontin & hyaluronic acid with respect to radiological
grade and a positive correlation between osteopontin and K/L grade & hyaluronic acid
and K/L grade implies that osteopontin has a significant role in activating MMP-13
causing degradation of articular cartilage and release of HA into the circulation in OA.
Hence osteopontin and hyaluronic acid can be used in combination as biomarkers to
assess the severity of the disease
