FRI0077 Levels of mir-16 in serum associate with response to therapy in patients with early rheumatoid arthritis
Authors: M. Filkova, C. Ospelt, S. Vettori, L. Šenolt, H. Mann, J. Vencovský, K. Pavelka, B. A. Michel, R. E. Gay, S. Gay, A. Jüngel
Journal: Annals of the Rheumatic Diseases (2013)

<h3>Background</h3> Studies have shown a beneficial effect of early treatment on clinical outcome and reduction in joint damage in patients with rheumatoid arthritis (RA). MiRNAs are stably present in cell-free form in body fluids and circulating miRNAs are becoming new candidate biomarkers for diagnosis and prognosis in different diseases. MiR-16 was shown to be of higher expression in synovial fluids and peripheral blood mononuclear cells in patients with RA compared with osteoarthritis (Murata et al. 2010, Pauley et al. 2008). <h3>Objectives</h3> To analyze miR-16 in sera of patients with early RA (ERA) to find a tool to monitor disease outcome. <h3>Methods</h3> Total RNA was isolated using phenol-chloroform extraction from sera of patients with ERA (n=34, disease duration &lt;8 months) before and after 3 months therapy with disease modifying antirheumatic drugs (DMARDs, methotrexate n=28, sulphasalazine n=4, leflunomide n=1) and glucocorticoids (n=30) as well as from patients with established RA (n=28, disease duration 9.28±6.52 years) treated with DMARDs (methotrexate n=14, sulphasalazine n=2, leflunomide n=8), glucocorticoids (n=6) or biologics (n=19). Clinical characteristics of ERA patients were assessed at baseline and after 3, and 12 months therapy. MiR-16 and let-7a, which was used as a normalization control, were reverse transcribed using specific primers with equal input of 12.5ng RNA and analyzed by TaqMan Real-Time PCR. Delta Ct method was used for relative quantification (dCt = Ct let-7a - Ct miR-16)<b>.</b> <h3>Results</h3> MiR-16 was found at significantly lower levels in sera of patients with ERA before treatment (dCt 4.93±0.91) than in patients with established RA (dCt 6.10±1.22, p&lt;0.001). After 3 months treatment with DMARDs, circulating miR-16 significantly increased in ERA sera in comparison with baseline (dCt 4.93±0.91 vs. 5.71±1.27, p=0.007). Baseline levels of miR-16 correlated with the change in DAS28 from baseline to 3 months follow up (r=-0.478, p=0.008): patients with low levels of miR-16 at baseline showed only a small decrease in DAS28 while patients with high levels of miR-16 at baseline showed a greater improvement in disease outcome from baseline to 3 months follow up. Similarly, the levels of miR-16 at 3 months follow up correlated with a change in disease activity DAS28 from 3 months to 12 months follow up (r=-0.355, p=0.047). Importantly, the change in levels of miR-16 from baseline to 3 months follow up was negatively associated with the change in DAS28 from 3 to 12 months follow up (r=-0.519, p=0.002) suggesting that the increase in circulating miR-16 within first 3 months after treatment initiation was followed by the decrease in disease activity in the subsequent 9 months. <h3>Conclusions</h3> Analysis of levels of miR-16 in sera may become a novel tool to monitor disease outcome and thereby a response to therapy in patients with ERA. <h3>Acknowledgements</h3> This work was supported by IMI BTCure, IAR, Masterswitch-PF7, Articulum and MH CR project No.023728. <h3>Disclosure of Interest</h3> None Declared