Abstract 13662: Superior Vena Cava Blood Up-Regulates RNA Expression of Vascular Remodeling Pathways in Lung Endothelial Cells

Abstract

Introduction: Pulmonary arteriovenous malformations (PAVMs) are common sequelae of single ventricle congenital heart disease (CHD), yet their pathogenesis are poorly understood. Clinical observations indicate that superior vena cava (SVC) blood induces PAVMs, whereas hepatic vein (HV) blood prevents and resolves PAVMs. Using paired SVC and HV blood samples from children with single ventricle CHD, we previously identified multiple protein differences between HV and SVC serum. To determine whether HV and SVC serum differentially impact gene expression in lung endothelial cells, we compared mRNA levels after incubation with HV and SVC serum. Hypothesis: We hypothesize that HV serum induces gene expression associated with endothelial quiescence, whereas SVC serum promotes genes expression associated with vascular remodeling. Methods: HV and SVC blood were collected in the cardiac catheterization lab from children with single ventricle CHD and Glenn circulation. HV and SVC serum (10% concentration) were incubated with human pulmonary microvascular endothelial cells (PromoCell) for 48 hours. After RNA isolation and reverse transcription, mRNA levels of 84 target genes were quantified using Qiagen RT 2 Profiler Angiogenesis Array (PAHS-024Z). Statistically significant differences in expression were identified with absolute fold difference >1.2 and p < 0.05. Results: Samples from 8 patients (63% male, median age 40 months [25.75, 45.25]) were included. Fifteen genes were differentially expressed, including 2 over-expressed with HV treatment (ANGPTL4 [+1.78 fold] and FGF1 [+1.46]) and 13 over-expressed with SVC treatment. Multiple processes were up-regulated in the SVC cohort: VEGF signaling (VEGFR2 [-1.21 fold], NRP1 [-1.42], VEGFR1 [-1.49]), EC adhesion/migration (ITGB3 [-1.40], EFNA1 [-1.40], EFNB2 [-1.39]), angiopoietin-TIE signaling (TIE2 [-1.31]), pericyte signaling (PDGF-A [-1.50], monocyte recruitment (CCL2 [-2.09]), and matrix remodeling (MMP2 [-1.65], FN1 [-1.33]). Conclusions: SVC serum up-regulates multiple vascular remodeling pathways in lung microvascular endothelial cells, potentially representing a pathologically activated endothelial phenotype. In contrast, HV serum promotes endothelial quiescence.