Abstract
BACKGROUND: Cardiovascular diseases remain important causes of morbidity and potential premature mortality in children. Although clinical imaging and electrophysiologic testing have advanced, early, minimally invasive biomarkers that can both detect myocardial injury and help differentiate among overlapping pediatric phenotypes are still limited. Circulating microRNAs (miRNAs; miRs) are becoming attractive biomarker candidates because many are abundant in the heart, actively released into the circulation, and remarkably stable in plasma. The study aimed to assess the expression of miR-1-3p, miR-let-7b-5p, miR-21-5p, and miR-26b-5p in children with cardiovascular disease. METHODS: Children aged 10-18 years with cardiac arrhythmias, myocarditis, or cardio-myopathies were recruited. The control group consisted of healthy age- and sex-matched children. For each participant, peripheral venous blood was collected for plasma isolation and miRNA profiling. The expression of miR-1-3p, miR-let-7b-5p, miR-21-5p, miR-26b-5p, and UniSp6 molecules was analyzed using the comparative cycle threshold delta Ct (ΔCt) method. A p-value ≤ 0.05 was considered statistically significant. RESULTS: miR-26b-5p was significantly downregulated in patients with cardiac disease compared with healthy controls. miR-21-5p and miR-26b-5p were downregulated in patients with ventricular arrhythmia. Moreover, miR-26b-5p was downregulated in arrhythmia in general. We found no significant difference in the expression of miR-1-3p, miR-let-7b-5p, miR-21b-5p, and miR-26b-5p between patients with and without myocarditis, as well as with and without hypertrophic cardiomyopathy. CONCLUSIONS: miR-26b-5p may distinguish young patients with cardiovascular disease and those with arrhythmias from healthy individuals. miR-21-5p and miR-26b-5p may also be seen as potential biomarkers of ventricular arrhythmia. Further studies involving a larger sample size are required to obtain sufficient data and validate these findings.