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Background: Genome wide association study identified hedgehog interacting protein gene (HHIP) variants with chronic obstructive pulmonary disease and asthma. Loss of HHIP, a key regulator of the hedgehog signaling pathway, leads to impaired lung morphogenesis and lethality in animal models, through unimpeded sonic hedgehog expression blocking mesenchymal-expressed fibroblast growth factor 10 (FGF10). Since bronchopulmonary dysplasia (BPD) is also associated with altered lung development and worsens with stimuli including mechanical ventilation, reactive oxygen species, and inflammation, HHIP and FGF10 may be candidate genes., Methods: This was an observational, cohort study including extremely low birth weight infants that who developed BPD and those who did not. DNA was isolated from buccal swabs and subjected to allelic discrimination, using specific HHIP and FGF10 probes. Protein levels were measured in tracheal aspirates. Student's t test, Chi-square, Z test and logistic regression were used., Results: Demographic characteristics did not differ except that birth weight (715 ± 153 vs. 835 ± 132 g) and gestational age (25 vs. 26 weeks) were less in babies with BPD. HHIP variant rs13147758 (GG genotype) was found to be independently protective for BPD (odds ratio 0.35, 95% confidence interval 0.15-0.82, P = - 0.02). Early airway HHIP protein levels were increased in infants with BPD compared to those without [median (interquartile range) 130.6 (55.6-297.0) and 41.2 (22.1-145.6) pg/mL, respectively; P = 0.05]. The FGF10 single nucleotide polymorphisms were not associated with BPD., Conclusion: HHIP, as a regulator of lung bud formation, affects BPD susceptibility, and may be valuable in understanding the specific mechanisms for this disease as well as for identifying therapeutic targets in the era of personalized medicine.

Background: There is increased use of early nasal continuous positive airway pressure (NCPAP) to manage respiratory distress in preterm infants but optimal methods and factors associated with successful wean are not well defined. A systematic review was performed to define the corrected gestational age (CGA), weight to wean NCPAP and the methods associated with successful weaning of the NCPAP among preterm infants, along with factors affecting it., Methods: Searches were made of PubMed using the keywords-NCPAP, CPAP, weaning, withdrawal, preterm, and infants from its inception to January 1st, 2014, for studies in all languages but limited to humans. Previous reviews (including cross references) were also searched. We included all randomized and quasi-randomized controlled trials where preterm neonates were randomized to different NCPAP weaning strategies. Details of CGA, weight and methods used for weaning NCPAP were extracted along with factors which affect its withdrawal., Results: Seven studies met the search criteria. The successful wean was at 32 to 33 weeks CGA and at 1600 g. Three different methods were used for weaning were sudden, gradual pressure wean and gradual graded time off wean. Criteria for readiness, success and failure to wean were defined. Factors affecting successful weaning were intubation, anemia, infection and gastro-esophageal reflux., Conclusions: The successful wean was at 32 to 33 weeks CGA and 1600 g. Criteria for readiness, success and failure to wean are well defined. Sudden weaning may be associated with a shorter weaning time. Future trials are needed comparing weaning methods using defined criteria for readiness and success of NCPAP wean and stratify the results by gestational age and birth weight.