Pentosidine in serum and synovial fluid in patients with knee osteoarthritis and its potential role of prediction of osteoarthritis progression

Background

The role of molecular markers for prediction of osteoarthritis (OA) progression is not yet defined. Pentosidine, one of the well-characterized advanced glycation endproducts, may be a candidate.

Objectives

To study the role of pentosidine as a marker of knee OA, as a marker of progression of knee OA, and for correlation of pentosidine in serum and synovial fluid and correlation with other markers.

Methods

Pentosidine was estimated by our own HLPC method [1], and cartilage digomeric matrix protein (COMP) by an original sandwich ELISA with monoclonal antibodies 16-F 12 and 17 C 10 [2]. MMP-9, TIMP and YKL-40 were estimated by commercial ELISA kits. Joint space width was measured in the narrowest point of the tibiofemoral compartment by 0.1 caliper and magnifying glass.

Results

Eighty-nine patients with knee OA were included in the study and were followed for 2 years. The paired samples of serum and synovial fluid were obtained from 48 patients in second study. The joint space narrowing in 2 years was 0.4 ± 0.79 mm. The patients with knee OA had higher initial serum values of pentosidine than controls (P = 0.04) and also of TIMP (P = 0.04), MMP-9 (P = 0.02) and COMP (P = 0.05). The patients with initially higher serum levels of pentosidine had more rapid radiological progression than controls (r = 0.30), and the same was true for hyaluronic acid (r = 0.56). Serum pentosidine levels correlated with synovial fluid pentosidine levels (r² = 0.78). Mild correlation occurred between synovial fluid pentosidine and COMP levels (r² = 0.11, P < 0.05).

Conclusions

Serum pentosidine levels may be a new molecular marker for prediction of OA progression.