Atrial fibrillation recurrence and expression levels of apelin-regulating miRNAs

MicroRNAs have emerged as novel serum diagnostic biomarkers for various diseases. To understand the mechanisms of atrial fibrillation (AF), we are studying apelin-regulating miRNAs that might identify those individuals with an increased propensity to the arrhythmia. We recruited 68 patients with persistent or chronic AF. Of the 68 patients with AF, 38 present a persistent AF and underwent external electrical cardioversion. Quantitative Real-time PCR was performed with LNA probes and SYBR master mix for apelin-regulating miRNAs. High expression of hsa-miR-30b-5p (0.29-fold), hsa-miR-30c-5p (0.15-fold), hsa-miR-155-5p (0.29-fold), hsa-miR-142-3p (0.63-fold), hsa-miR-148-3p (0.13-fold) and hsa-miR-124-3p (1.2-fold) was found in AF group as compared to controls. Comparing the values of relative quantification among patients with AF recurrence after external electrical cardioversion and patients who maintained sinus rhythm we found a statistically significant difference only for the miR-30b-5p. Our studies confirm the hypothesis that apelin and apelinergic system plays a role in the pathophysiology of AF. The determination of cut-off values for miRNAs involved in the regulation of apelin could allow the creation of an effective prognostic score that can be useful to determine which therapeutic strategy to adopt in each patient according to his chances of maintaining the pace before cardioversion external power supply.