Serum concentrations of type II collagen biomarkers (C2C, C1, 2C and CPII) suggest different pathophysiologies in patients with hip osteoarthritis.

Background Cartilage destruction in osteoarthritis (OA) involves excessive degradation and increased synthesis of cartilage matrix macromolecules including type II collagen and proteoglycans. Cartilage biomarkers exist for the measurement of cartilage matrix turnover and may reveal differences in patients with OA. Objective To determine whether there are detectable differences in and relationships between biomarkers of type II collagen (CII) degradation (C2C, Cl, 2C) and synthesis (CP II) in patients with only hip OA (OHOA) and those suffering from multiple sites OA (MSOA). Patients and methods Fifty-six patients classified as MSOA or OHOA. Minimum hip joint space width (Min JSW) measured by computer from standard radiographs. Serum measurement of CII synthesis C-propeptide (CPII) and cleavage of type II (C2C) and types I and II (Cl, 2C) collagens. Aggrecan metabolism was assessed by serum CS 846 assay. Step to step logistic regression to determine the effect of the quantitative data on the assignment to each subgroup. Results Twenty-four subjects were classified with MSOA. Among the 32 OHAO patients, 15 had bilateral hip OA and 17 had unilateral hip OA. The latter were classified with "Isolated hip OA" (IHOA). CPII levels were significantly lower in patients with MSOA than in those with OHOA (99.9±50.3ng/mL versus 141.9±81.2ng/mL, p=0.04. OR= 0.18 for CPII >120 ng/mL, p 10 ng/mL, p=0.02). There was an inverse correlation between min JSW and C2C only in patients with IHOA (r=0.50, p= 0.02). Conclusion Hip OA, in patients with MSOA, might be related to alteration in CII metabolism which may result in a deficient type II collagen repair process. The significant relationship between C2C and JSW in IHOA suggests that this marker is of value in assessing cartilage degradation patients with involvement of a single joint.