Circulating miR-489 as a potential new biomarker for idiopathic dilated cardiomyopathy.

Objectives: MicroRNAs (miRNA) are functional RNAs that have emerged as pivotal gene expression regulators in cardiac disease. Although several cardiomyocyte miRNAs have been reported to play roles in heart failure progression among patients with idiopathic dilated cardiomyopathy (DCM), the role of circulating miRNAs has not yet been well-examined.

Methods: After total RNA extraction from the peripheral blood samples of three control participants and six patients with DCM, miRNA profiling was performed using miRNA arrays. Based on the results of this initial screening, real-time polymerase chain reaction (RT-PCR) was used to perform a quantitative analysis of blood samples from a larger number of matched patients (DCM, =20; controls, =5). Finally, the correlations between specific miRNA expression levels and hemodynamic parameters were analyzed.

Results: A primary screening of 2,565 miRNAs resulted in the identification of nine miRNA candidates. Quantitative RT-PCR results revealed significantly increased miR-489 expression levels in the DCM group. Moreover, there was a significant positive correlation between miR-489 expression level and left ventricular ejection fraction.

Conclusions: Our results suggest that circulating miR-489 could be a potential noninvasive diagnostic biomarker for DCM. Additionally, the quantification of circulating miR-489 may have value as a potential prognostic marker for patients with DCM.