To address the knowledge gap of the effects of Areg on the developing lung vasculature, we studied the effects of hyperoxia (HO), a commonly used insult to model BPD using newborn mice [26,27,28,29] and lung endothelial cells (ECs) [30,31], on Areg expression in whole lungs and lung ECs. This evidence concerns the gene AREG and bronchopulmonary dysplasia.