[The role of type II collagen fragments and X-ray progression of knee osteoarthritis]. / Rôle des marqueurs de dégradation du collagène de type II au cours de la progression de l'arthrose du genou.

AIMS: To investigate the association between type II collagen fragments and the presence of knee osteoarthritis (OA) in the Tunisian population and to determine whether this biomarker can predict X-ray progression of this disease. METHODS: Type II collagen C-telopeptide (uCTX-II) and helical peptide (sHelix-II) were assessed in 125 female patients with knee osteoarthritis aged 54 ± 8 years over 2 years and 57 female age-matched controls. The markers were measured at baseline, 1 and 2 yrs' follow-up corresponding to x-ray time points. RESULTS: Only urinary CTX-II values were significantly 48% higher in knee OA patients compared with controls (p=0.001). The longitudinal changes over 2 yrs in Helix-II were also significantly associated with Joint Space Narrowing: JSN (p=0.03). Over the 2-yr study period average CTX-II levels were not significantly higher in progressor compared with non-progressor (339.96 vs 256.00; NS). CONCLUSION: The data presented here suggest that CTX-II may be useful to identify patients with knee OA. These results demonstrate significantly association between progression of this disease and alterations levels of Helix-II.

Association of serum levels of aggrecan ARGS, NITEGE fragments and radiologic knee osteoarthritis in Tunisian patients.

OBJECTIVES: Proteolytic degradation of aggrecan is a hallmark of the pathology of osteoarthritis. The aim of this study was to develop enzyme-linked immunosorbent assay (ELISA) to quantify the serum levels of specific aggrecan fragments generated by aggrecanases-mediated cleavage. We investigated the relationships between these two aggrecan degradations fragments and urinary CTX-II levels. METHODS: The competitive ELISAs employ a polyclonal antibody raised against the aggrecan fragments containing two neoepitopes NITEGE(373)and (374)ARGSVI. We measured serum levels of ARGSV and NITEGE in 125 women with knee osteoarthritis (mean±SD age of 53.6±7.6 years, mean±SD disease duration of 3.6±3.8 years), and 57 women age-matched controls. RESULTS: Aggrecan neoepitopes assays showed an intra- and inter-assay imprecision (CV) lower than 20% for both tests and good linearity. Median serum ARGSVI (by 18%; P=0.002), and NITEGE (36.4%; P<0.001) levels were significantly decreased in patients with knee osteoarthritis compared with controls. Minimal joint space width was negatively correlated with ARGSVI (r=-0.368, P=0.04) and NITEGE (r=-0.274, P=0.038) in knee osteoarthritis patients. Median urinary CTX-II levels were significantly increased by 39.5% (P=0.001) in knee OA patients compared with controls. CONCLUSION: Markers of degradation aggrecan were analyzed for the first time in an African osteoarthritis population. These markers can be used to monitor aggrecanase activity in human joint disease. Their combination with CTX-II can improve clinical investigation of patients with osteoarthritis patients.