AB0032 LOCAL EXPRESSION OF miRNAS IN OSTEOARTHRITIS PATIENTS

Background Microribonucleic acids (miRNAs) comprise a class of small non-coding RNAs that negatively regulate the gene expression on posttranscriptional level. Altered expression of miRNAs has been described systemically as well as locally in the inflamed joints of patients with osteoarthritis (OA) [1-3]. Objectives The aim of our study was to evaluate the synovial fluid (SF) expression of miRNA-146a (miR-146a), miR-155, miR-193 in OA patients and to determine their role as potential diagnostic biomarkers for this disease. Methods 16 OA patients were included in the analysis. Expression levels of miR-146a, miR-155 and miR-193b in SF samples were determined by qPCR (SybrGreen technology) and compared to healthy controls (HCs). Relative changes of gene expression levels of the studied miRNAs were calculated by 2-ΔΔCt method. SPSS v20 was used for statistical analysis. Results OA SF showed statistically significant overexpression of miR-146a (in 75.00%), of miR-155 (in 68.75%) and of miR-193b (in 75.00%) when compared to HCs and these miRNAs could be used to differentiate OA from HCs (p=5.9x10-3, p=0.043 and p=5.5x10-3, respectively). Receiver operating characteristic (ROC) curve analysis was constructed in order to evaluate the diagnostic accuracy of the studied miRNAs in SF to distinguish OA from HCs by using relative expression (RQ) values. Area under the curve (AUC) for miR-146a was 0.830 (95%CI=0.674÷0.985, with 75.00% sensitivity and 72.70% specificity, p=0.004), AUC for miR-155 was 0.767 (95% CI=0.582÷0.952, with 75.00% sensitivity and 54.50% specificity, p=0.020) and AUC for miR-193b was 0.801 (95% CI =0.622÷0.981, with 87.50% sensitivity and 63.60% specificity, p=0.009). There was a correlation between the SF expression levels of miR-146a and miR-193b and the radiographic stage of the disease (р=0.0071 and р=0.0105, respectively). SF levels of miR-146a and miR-155 correlated with the SF cell count (р=5.16х10-3 and р=0.0188, respectively). Conclusion We found an altered SF expression of miR-146a, miR-155 and miR-193b in OA patients when compared to HCs and these miRNAs could serve as potential diagnostic biomarker for inflammatory OA. Larger sets are needed to confirm the diagnostic accuracy of the studied miRNAs in OA. References [1]Murata K, Yoshitomi H, Tanida S, Ishikawa M, Nishitani K, Ito H, Nakamura T. Plasma and synovial fluid microRNAs as potential biomarkers of rheumatoid arthritis and osteoarthritis. Arthritis Res Ther., 2010; 12(3):R86. [2]Oliviero A, Della Porta G, Peretti GM, Maffulli N. MicroRNA in osteoarthritis: physiopathology, diagnosis and therapeutic challenge. Br Med Bull., 2019; 130(1):137-147. [3]Panagopoulos PK, Lambrou GI. The Involvement of MicroRNAs in Osteoarthritis and Recent Developments: A Narrative Review. Mediterr J Rheumatol., 2018; 29(2):67-79. Acknowledgements The study was supported by Grant 14D/2012 and Grant 55/2013 from the Medical University-Sofia. Disclosure of Interests None Declared.