Osteoarthritis: Insights into Potential Causes and Biomarkers from Articular Fluid Metabonomics

Background: Osteoarthritis (OA) is one of the leading causes of pain and disability. Metabolomics is a recent approach to identifying moieties that can be used in diagnosis, prognosis, and as biomarkers. The articular fluid in OA witnesses its pathophysiology directly. Identifying differential metabolites and biological pathways associated with them can provide in-depth mechanisms and identify biomarkers. Aim: In the present study, synovial fluid of confirmed OA patients (n=17) and matched healthy controls (n=21) was investigated for differential metabolites using untargeted metabolomics. Methods: The distribution of the samples was observed using multidimensional PCA. The signaling pathways associated with metabolites were obtained by pathway enrichment analysis, and a correlation analysis of differential metabolites was performed to identify common and significant metabolites. Results: A total of 16 upregulated and 23 downregulated metabolites (log2foldchange >0.5, p<0.05) were identified by differential analysis. The essential amino acid, arginine, was recognized as the most significant metabolite present in most of the identified deregulated pathways. The pathways, arginine, and proline metabolisms, and mTOR, were found to be deregulated strongly in the present study. Conclusion: These metabolites and their associated pathways can be beneficial for the diagnosis and treatment of osteoarthritis in clinical settings after further validation in large cohorts.