Postnatal growth restriction is quite common in preterm infants; its presence and its combination with hyperoxia result in decreased expression of key modulators of angiogenesis and vascular tone including VEGF, VEGF receptor 2, HIF1α, HIF2α, eNOS and NOS metabolites [74], again suggesting the importance of the vascular hypothesis in BPD development, but many other mechanisms could be involved [76]. Here, VEGFA is linked to bronchopulmonary dysplasia.