Circulating microRNAs as biomarkers for myocardial fibrosis in patients with left ventricular non-compaction cardiomyopathy

Introduction: Despite the fact that cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) is a proven method for detecting myocardial fibrosis, there is a need for new and reliable serological biomarkers. Circulating miRNAs could be a practical and attractive alternative. The purpose of the study was to assess the miRNAs well established in myocardial fibrosis - miR-21, miR-29a, miR-30d and miR-133a - in the plasma of patients with left ventricular non-compaction (LVNC) that have areas of LGE assessed by CMR. Material and methods: We prospectively enrolled 13 adult patients (9 males and 4 females; mean age: 39 +/- 11.7 years) considered to meet standard CMR criteria for LVNC and 10 healthy age-and sex-matched subjects. All LVNC patients and control subjects underwent CMR examination and the measurement of peripheral plasma levels of 4 miRNAs: miR-21, miR-29a, miR-30d and miR-133a. Results: The LGE was present in 9 of the 13 (69.2%) LVNC patients, and most often located in the ventricular septum. Compared with LGE-negative patients, LGE-positive patients had significantly lower LVEF (28.3 +/- 13.3% vs. 53.5 +/- 14.9%, p = 0.0113) and greater LV end-diastolic diameter (67.8 +/- 9.5 mm vs. 57 +/- 2.2 mm, p = 0.01). Significant up-regulation of all 4 miRNAs was observed among LGE-positive patients vs. LGE-negative patients: miR-21 (p = 0.007), miR-29a (p = 0.0001), miR-30d (p = 0.001) and miR-133a (p = 0.0003). Conclusions: The up-regulation of miR-21, miR-29a, miR-30d and miR-133a indicates the presence of LGE in LVNC patients, and therefore they may serve as potential biomarkers for myocardial fibrosis.