Animal studies using the neonatal rodent hyperoxia model of experimental BPD have shown promise for non-selective PDE inhibitor pentoxyfilline (90), PDE4 inhibitors rolipram, piclamilast, and cilomilast (91–93), and PDE5 inhibitor sildenafil (94), which were able to ameliorate pulmonary inflammation and hypertension and improve lung alveolarization. Here, ALDH7A1 is linked to bronchopulmonary dysplasia.