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.

[Efficacy and safety of inhalation of pulmonary surfactant using vibrating mesh nebulizers combined with nasal continuous positive airway pressure in the treatment of neonatal respiratory distress syndrome].

OBJECTIVE: To investigate the efficacy and safety of nasal continuous positive airway pressure (NCPAP) combined with inhalation of pulmonary surfactant (PS) using vibrating mesh nebulizers in the treatment of neonatal respiratory distress syndrome (RDS). METHODS: A prospective study was performed on premature infants with RDS admitted to the First Affiliated Hospital of Bengbu Medical College between December 2020 and June 2021. They were randomly assigned into vibrating mesh atomization technology group and intubation-surfactant-extubation (INSURE) technology group. The two groups were treated with NCPAP combined with PS. PS in the vibrating mesh atomization technology group was inhaled into the lungs by the new vibrating mesh atomization technology, while PS in the INSURE group was injected into the lungs by endotracheal tube. The pH value, arterial partial pressure of carbon dioxide (PaCO2), oxygenation index (PaO2/FiO2), mechanical ventilation via endotracheal tube (MVET) demand rate, duration of respiratory support, secondary use of PS, complications, and hospital mortality were compared between the two groups. The occurrences of adverse events in the two groups were recorded. RESULTS: A total of 42 preterm infants were finally enrolled, including 20 cases in the vibrating mesh atomization technology group and 22 cases in the INSURE technology group. There were no significant differences in blood gas analysis and PaO2/FiO2 before PS administration between the two groups. One hour after PS administration, blood gas analysis and PaO2/FiO2 were significantly improved in both groups. Compared with the INSURE technology group, the improvement of PaO2/FiO2 was more obvious in the vibrating mesh atomization technology group [mmHg (1 mmHg≈0.133 kPa): 198±34 vs. 173±39, P < 0.05], but no significant difference in pH value or PaCO2 was found between the two groups. The duration of respiratory support in the vibrating mesh atomization technology group was significantly shorter than that in the INSURE technology group (hours: 96±13 vs. 120±18, P < 0.01), but there was no statistical difference in MVET demand rate [5.0% (1/20) vs. 13.6% (3/22), P > 0.05]. The incidence of periventricular-intraventricular hemorrhage (PVH-IVH) in the vibrating mesh atomization technology group was less than that in the INSURE technology group [0% (0/20) vs. 18.2% (4/22)], but no statistical difference was found (P > 0.05). No significant differences in the secondary use rate of PS and incidence of bronchopulmonary dysplasia (BPD) or other complications were found between the vibrating mesh atomization technology group and the INSURE technology group [5.0% (1/20) vs. 9.1% (2/22), 5.0% (1/20) vs. 4.5% (1/22), both P > 0.05]. There were no deaths or serious adverse events such as pneumothorax, pulmonary hemorrhage, periventricular leukomalacia (PVL), retinopathy of prematurity (ROP), and necrotizing enterocolitis (NEC) in both groups. CONCLUSIONS: Compared with the INSURE technique, NCPAP combined with vibrating mesh atomization technology was also effective and safe in the treatment of RDS, which could significantly improve PaO2/FiO2 and shorten the duration of respiratory support. Thus, it was worthy of clinical popularization and application.