Studies in autopsies of infants who died from BPD have shown a decrease in the expression of the endothelial cell marker platelet/endothelial cell adhesion molecule-1 (PECAM-1), and vascular endothelial growth factor (VEGF), which are related to the dysmorphic and abnormal distribution of alveolar capillaries in thickened alveolar septa (14, 30). Here, PECAM1 is linked to bronchopulmonary dysplasia.