Abstract 16661: Circulating microRNAs as Prognostic Biomarkers in Single Ventricle Heart Disease

Introduction: Despite significant improvements in surgical technique and post-surgical management, mortality remains high for infants with single ventricle congenital heart disease (SV) and the ability to risk-stratify infants with SV is limited. microRNAs (miRs) are short regulatory RNAs that modulate gene expression and miRs in the circulation are increasingly recognized as valuable biomarkers in a broad range of diseases. Hypothesis: Circulating miR profiles prior to surgical palliation may correlate with SV survival at one year and assist with risk-stratification in this population. Methods: Serum samples from subjects with SV (of right ventricular morphology) were obtained at the following time points: Pre-Norwood (n=71), Pre-Glenn (n=46) and Pre-Fontan (n=25). Outcomes were classified as alive versus death or heart transplant listing by one year of age. Serum was subject to three freeze/heat cycles to maximize miR release, then miRs were reverse transcribed using a pool of primers specific for each miR. Real-time PCR was performed in 384-well plates containing sequence-specific primers and TaqMan probes in the ABI7900HT. Results: Random forest analysis of Pre-Norwood samples demonstrates downregulation of miRs-194, -15b and -193b in patients who died or required heart transplant listing (n=22) compared to those who were alive (n=49). Hierarchical clustering based on these 3 specific miRs is demonstrated in Figure 1 (blue = alive, red = death/transplant). miRs-483-5p, -140-3p and -30b are differentially expressed between the Pre-Norwood, Pre-Glenn, and Pre-Fontan groups and are associated with each surgical stage. Conclusions: Circulating miRs demonstrate promise as prognostic biomarkers of 1-year outcome in the Pre-Norwood SV population. Circulating miR profiles are also distinct at each surgical stage. Notably, the identified miRs are known to regulate gene expression in other forms of heart disease and warrant further investigation.