Altered Pulmonary Artery Endothelial - Smooth Muscle Cell Interactions in Experimental Congenital Diaphragmatic Hernia

BACKGROUND: Pulmonary hypertension (PH) secondary to vascular remodeling contributes to poor outcomes in congenital diaphragmatic hernia (CDH), however mechanisms responsible are unknown. We hypothesized that pulmonary artery endothelial cell (PAEC) dysfunction contributes to smooth muscle cell (SMC) hyperplasia in experimental CDH. METHODS: PAEC and SMC were isolated from fetal sheep with experimental CDH and controls. SMC growth was assessed alone and with SOD plus catalase and during co-culture with control or CDH PAEC with and without ET-1 siRNA transfection. ET-1 protein was measured in PAEC and PASMC lysates and supernatant. ROS production was measured in normal and CDH PAECs with and without ET-1 siRNA. PAEC growth and tube formation were measured with SOD plus catalase. RESULTS: CDH SMC growth was decreased and and increased with co-culture with CDH PAEC more than control PAEC. Treatment of CDH PAEC with SOD plus catalase or ET-1 siRNA prevented the increase in SMC growth seen with co-culture. ET-1 protein was increased in CDH PAEC and SMC. ROS production was increased in CDH PAEC and decreased with ET-1 SiRNA. SOD plus catalase restored CDH PAEC growth and tube formation. CONCLUSIONS: PAEC dysfunction in experimental CDH increases SMC proliferation via ET-1 induced ROS production by PAEC.