Proteomic analysis of human articular cartilage unravels the dyscoagulation in osteoarthritis and the potential value of serpinA5 as a biomarker for osteoarthritis

PURPOSE: Nowadays, there is no clinically applicable biomarker for osteoarthritis (OA). Therefore, the aim of the study is to discover a potential biomarker for OA. EXPERIMENTAL DESIGN: We performed a proteomics of eight cartilage samples (four damaged cartilage and four macroscopically intact cartilage) from four OA patients without any comorbidities to search for valuable OA biomarkers. Four rats underwent bilateral ovariectomy to induce the OA (OVX-OA) model, while another four underwent a sham procedure wherein the ovaries were exteriorized but not removed (SHAM). Selected candidate proteins were further verified in the patients and the OVX-OA animal model. RESULTS: A comprehensive cartilage proteome profile of patients with OA was constructed. Additionally, the complement and coagulation cascades were found to be significantly altered, and serpinA5 was chosen as a protein of interest based on biological information analysis. The reduction of serpinA5 in locally damaged cartilage and serum of patients with OA compared to the control group was determined. Furthermore, we found that serpinA5 was decreased in OVX-OA rats compared to that in SHAM rats. CONCLUSIONS AND CLINICAL RELEVANCE: Our results suggest that there is dyscoagulation in the OA process and that serpinA5 can serve as a potentially valuable OA biomarker.