The role of rhIGF-1/BP3 in the prevention of pulmonary hypertension in bronchopulmonary dysplasia and its underlying mechanism.

BACKGROUND: This study aimed to determine whether postnatal treatment with recombinant human IGF-1 (rhIGF-1)/binding peptide 3 (BP3) ameliorates lung injury and prevents pulmonary hypertension (PH) in bronchopulmonary dysplasia (BPD) models. METHODS: We used two models of BPD in this study: one model that was associated with chorioamnionitis (CA), stimulated by intra-amniotic fluid and exposure to lipopolysaccharide (LPS), whereas the other was exposed to postnatal hyperoxia. Newborn rats were treated with rhIGF-1/BP3 (0.2 mg/Kg/d) or saline via intraperitoneal injection. The study endpoints included the wet/dry weight (W/D) ratio of lung tissues, radial alveolar counts (RACs), vessel density, right ventricular hypertrophy (RVH), lung resistance, and lung compliance. Hematoxylin and eosin (H&E) and Masson staining were used to evaluate the degree of lung injury and pulmonary fibrosis. IGF-1 and eNOS expression were detected using western blotting or quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). The levels of SP-C, E-cadherin, N-cadherin, FSP1, and Vimentin in the lung tissues were detected by immunofluorescence. RESULTS: LPS and hyperoxia treatment increased lung injury and pulmonary fibrosis, enhanced RVH and total respiratory resistance, and decreased RAC, pulmonary vascular density and pulmonary compliance in young mice (all p < 0.01). Simultaneously, LPS and hyperoxia induced an increase in epithelial-mesenchymal transition (EMT) in airway epithelial cells. However, rhIGF-1/BP3 treatment reduced lung injury and pulmonary fibrosis, decreased RVH and total respiratory resistance, and enhanced RAC, pulmonary vascular density and pulmonary compliance, as well as inhibited EMT in airway epithelial cells in LPS and hyperoxia treated mice. CONCLUSION: Postnatal rhIGF-1/BP3 treatment relieved the effects of LPS or hyperoxia on lung injury and prevented RVH, providing a promising strategy for the treatment of BPD.

[A randomized controlled study of nasal intermittent positive pressure ventilation in the treatment of neonatal respiratory distress syndrome].

OBJECTIVE: To compare the clinical effects of nasal intermittent positive pressure ventilation (NIPPV) and nasal continuous positive airway pressure (NCPAP) in the treatment of neonatal respiratory distress syndrome. METHODS: A prospective, randomized, controlled, single-center study was performed on 67 premature infants with NRDS between March 2011 and May 2012 and selected according to the inclusion and exclusion criteria. These premature infants were randomly assigned to receive NIPPV and NCPAP. Oxygenation index (OI), pH, PaCO2, duration of respiratory support, complications, success rate, hospital mortality, and incidence of bronchopulmonary dysplasia (BPD) were compared between the two groups. RESULTS: Sixty-two patients were finally enrolled in the study, including 32 cases in the NIPPV group and 30 cases in the NCPAP group. After one hour of non-invasive ventilation, OI in the NIPPV group was higher than the NCPAP group (P<0.05), but there were no significant differences in pH and PaCO2 between the two groups (P>0.05 for both). A significantly lower proportion of infants needed mechanical ventilation via endotracheal tube (MVET) when they were treated initially with NIPPV than when they were treated initially with NCPAP (P<0.05). The NIPPV group had a significant higher success rate than the NCPAP group (P<0.05), but there was no significant difference in duration of respiratory support between the two groups (P>0.05). In addition, no significant differences in incidence of pneumothorax, hospital mortality and incidence of BPD were seen between the two groups (P>0.05 for all). CONCLUSIONS: Compared with NCPAP, NIPPV can significantly decrease the proportion of premature infants with NRDS in need of MVET. However, there is no evidence that NIPPV can significantly reduce hospital mortality and incidence of BPD in premature infants with NRDS.