Bone Abstracts

Biomarkers are required to detect early OA for intervention and to monitor disease progression. A collagen type II neoepitope C2C was developed for these purposes. The aims of the study to test: i) the biomarker’s ability to differentiate osteo-arthritis (OA) patients with and without structural changes and ii) possible contribution of progression of the OA.

Material and methods: We investigated 159 knee OA patients aged 36–62 (mean 50) years. For 112 patients the progression of the knee OA during the past 3 years was available. Standardised radiographs of the tibiofemoral (TF) and patello-femoral (PF) joints were assessed. Radiographic progression was defined as: i) the presence of osteophytes and/or joint space narrowing (JSN) in subjects with no previous radiographic OA or ii) an increase in the grade of them.

The immunoassay used was C2C-HUSA (IBEX, Canada) that measures the C2C neoepitope fragments present in human urine samples.

Results: The most frequent radiographic finding was osteophytosis in the PF compartment. A significant correlation (ρ=0.460, P<0.0001) between output of uC2C and TF grades of OA was found. There was a highly significant difference in uC2C between the groups with TF grade 0 and grade 2 (or 3). UC2C excretion was significantly higher in patients with progressive OA (P<0.0001).

A large part of the variability of knee OA was describable by clinical risk factors, i.e. age, gender, and overweight. In case uC2C was added into models, description of variability of osteophytosis in the TF joint improved the model from 15 to 24%, and in the PF joint – from 4 to 23%.

Conclusions: Presence of osteophytosis, whether isolated or in combination with the JSN form, played a crucial role in this series.

UC2C excretion was significantly higher in patients with OA in comparison of cases without structural changes.

Many cases with progressive OA had increased output of uC2C.

A substantial impact of uC2C was observed in the models of osteophytosis.