Given that the level of Ang1 dynamically increases, while Ang2 decreases in the lung after birth [30] and that tracheal aspirate samples from the BPD model mouse have high levels of Ang2 [31], [32], the Ang/Tie2 pathway may play a crucial role in postnatal lung vascular and alveolar development. Here, TEK is linked to bronchopulmonary dysplasia.