Cell-Based Strategies to Reconstitute Lung Function in Infants with Severe Bronchopulmonary Dysplasia Abstract Extreme prematurity is one of the major risk factors for the development of chronic lung disease of prematurity or bronchopulmonary dysplasia (BPD). 1 Preterm infants born between 24 and 28 weeks of gestation (ie, extremely preterm) have an immature pulmonary surfactant system, immature airwa