Objective To assess the role of nasal continuous positive airway pressure (CPAP) initiated at birth for prevention of death and bronchopulmonary dysplasia in very preterm infants. Design Systematic review.Data sources PubMed, Embase, the Cochrane Central Register of Controlled Trials, and online Pediatric Academic Society abstracts from the year of inception to June 2013.Eligibility criteria for selecting studies Randomised controlled trials evaluating the effect of nasal CPAP compared with intubation in preterm infants born at less than 32 weeks' gestation and presenting the outcomes of either death or bronchopulmonary dysplasia, or both (defined as the need for oxygen support or mechanical ventilation at 36 weeks corrected gestation), during hospital stay.Results Four randomised controlled trials (2782 participants) met the inclusion criteria, with 1296 infants in the nasal CPAP group and 1486 in the intubation group. All the trials reported bronchopulmonary dysplasia independently at 36 weeks corrected gestation, with borderline significance in favour of the nasal CPAP group (relative risk 0.91, 95% confidence interval 0.82 to 1.01, risk difference −0.03, 95% confidence interval −0.07 to 0.01). No difference in death was observed (relative risk 0.88, 0.68 to 1.14, risk difference −0.02, −0.04 to 0.01, respectively). Pooled analysis showed a significant benefit for the combined outcome of death or bronchopulmonary dysplasia, or both, at 36 weeks corrected gestation for babies treated with nasal CPAP (relative risk 0.91, 0.84 to 0.99, risk difference −0.04, -0.07 to 0.00), number needed to treat of 25). ConclusionOne additional infant could survive to 36 weeks without bronchopulmonary dysplasia for every 25 babies treated with nasal CPAP in the delivery room rather than being intubated.

O'Reilly M, Thébaud B. Animal models of bronchopulmonary dysplasia. The term rat models. Am J Physiol Lung Cell Mol Physiol 307: L948 -L958, 2014. First published October 10, 2014; doi:10.1152/ajplung.00160.2014.-Bronchopulmonary dysplasia (BPD) is the chronic lung disease of prematurity that affects very preterm infants. Although advances in perinatal care have enabled the survival of infants born as early as 23-24 wk of gestation, the challenge of promoting lung growth while protecting the ever more immature lung from injury is now bigger. Consequently, BPD remains one of the most common complications of extreme prematurity and still lacks specific treatments. Progress in our understanding of BPD and the potential of developing therapeutic strategies have arisen from large (baboons, sheep, and pigs) and small (rabbits, rats, and mice) animal models. This review focuses specifically on the use of the rat to model BPD and summarizes how the model is used in various research studies and the advantages and limitations of this particular model, and it highlights recent therapeutic advances in BPD by using this rat model. hyperoxia; lung development; premature birth BRONCHOPULMONARY DYSPLASIA (BPD) is the most common chronic lung disease of very preterm infants. BPD interrupts lung development and has serious long-term respiratory complications that reach beyond childhood and into adult life (8,25,26,41,53). The multifactorial etiology of BPD has prompted research to investigate the many factors contributing to the pathogenesis of BPD (reviewed in Ref. 38), with the ultimate aim of developing effective therapies to prevent longterm pulmonary sequelae. To investigate the effectiveness of various therapeutic strategies on the development, structure, and function of the lungs, it is important to have animal models that reliably reproduce some of the features observed in very preterm infants developing BPD. To achieve this, known contributing factors of BPD, such as perinatal inflammation, growth restriction, hyperoxia, and mechanical ventilation, have been used in both large and small animals to mimic the BPD-like lung injury. In particular, exposure of neonatal rats to hyperoxia is extensively utilized as a small animal model of experimental BPD. Characterization of the Rat Model of Experimental BPDExposing the immature rat lung to hyperoxic gas through neonatal life closely reproduces the histopathology observed in human infants with BPD. Studies have shown that exposure of the developing rat lung to hyperoxic gas can have detrimental effects, particularly on the structure of the gas-exchanging region (14,30,34,46,62,66). The main overall finding, which is common to each study, is that exposure of the immature lung to hyperoxic gas impairs alveolarization, resulting in fewer and enlarged alveolar air spaces. Pulmonary hypertension, disrupted vascular growth, vascular leakage, accumulation of plasma proteins, extravascular fibrin deposition, increased lung collagen content, increased inflammatory cell influx, and diso...

Background Bronchopulmonary dysplasia and emphysema are life-threatening diseases resulting from impaired alveolar development or alveolar destruction. Both conditions lack effective therapies. Angiogenic growth factors promote alveolar growth and contribute to alveolar maintenance. Endothelial colony-forming cells (ECFCs) represent a subset of circulating and resident endothelial cells capable of self-renewal and de novo vessel formation. We hypothesized that resident ECFCs exist in the developing lung, that they are impaired during arrested alveolar growth in experimental bronchopulmonary dysplasia, and that exogenous ECFCs restore disrupted alveolar growth. Methods and Results Human fetal and neonatal rat lungs contain ECFCs with robust proliferative potential, secondary colony formation on replating, and de novo blood vessel formation in vivo when transplanted into immunodeficient mice. In contrast, human fetal lung ECFCs exposed to hyperoxia in vitro and neonatal rat ECFCs isolated from hyperoxic alveolar growth–arrested rat lungs mimicking bronchopulmonary dysplasia proliferated less, showed decreased clonogenic capacity, and formed fewer capillary-like networks. Intrajugular administration of human cord blood–derived ECFCs after established arrested alveolar growth restored lung function, alveolar and lung vascular growth, and attenuated pulmonary hypertension. Lung ECFC colony- and capillary-like network-forming capabilities were also restored. Low ECFC engraftment and the protective effect of cell-free ECFC-derived conditioned media suggest a paracrine effect. Long-term (10 months) assessment of ECFC therapy showed no adverse effects with persistent improvement in lung structure, exercise capacity, and pulmonary hypertension. Conclusions Impaired ECFC function may contribute to arrested alveolar growth. Cord blood–derived ECFC therapy may offer new therapeutic options for lung diseases characterized by alveolar damage.