Specific circulating microRNA signature of bicuspid aortic valve disease

Background: We aimed to determine the circulating miRNA expression profile associated with BAV and aortic dilation to provide diagnostic and prognostic biomarkers for BAV and/or aortic dilation. Methods and results: We applied a miRNome-wide microarray approach using plasma samples (n = 24) from healthy tricuspid aortic valve individuals, BAV patients and BAV patients with aortic dilation to compare and identify the specific miRNAs associated with BAV and aortic dilation. In a second stage, the expression patterns of the miRNA candidates were validated by RT-qPCR in an independent cohort (n = 43). The miRNA microarray data and RT-qPCR analyses revealed that the expression levels of circulating miR-122, miR-130a and miR-486 are significantly influenced by the morphology of the aortic valve (bicuspid/tricuspid) and could be functionally involved in the regulation of TGF-beta(1) signalling. Furthermore, the expression pattern of miR-718 in the plasma was strongly influenced by dilation of the ascending aorta. miR-718 expression was inversely correlated with the aortic diameter (R = -0.63, p = 3.1 x 10(-5)) and was an independent predictor of aortic dilation (beta = -0.41, p = 0.022). The genes targeted by miR-718 are involved in the regulation of vascular remodelling. Conclusions: We propose that miR-122, miR-130a, miR-486 and miR-718 are new molecular features associated with BAV and aortic dilation principally by the activation of TGF-beta(1) pathway and vascular remodelling mediated by VEGF signalling pathways.