Verification of immunology-related genetic associations in BPD supports ABCA3 and five other genes.

BACKGROUND: Inflammatory processes are key drivers of bronchopulmonary dysplasia (BPD), a chronic lung disease in preterm infants. In a large sample, we verify previously reported associations of genetic variants of immunology-related genes with BPD. METHODS: Preterm infants with a gestational age ≤32 weeks from PROGRESS and the German Neonatal Network (GNN) were included. Through a consensus case/control definition, 278 BPD cases and 670 controls were identified. We identified 49 immunity-related genes and 55 single-nucleotide polymorphisms (SNPs) previously associated with BPD through a comprehensive literature survey. Additionally, a quantitative genetic association analysis regarding oxygen supplements, mechanical ventilation, and continuous positive air pressure (CPAP) was performed. RESULTS: Five candidate SNPs were nominally associated with BPD-related phenotypes with effect directions not conflicting the original studies: rs11265269-CRP, rs1427793-NUAK1, rs2229569-SELL, rs1883617-VNN2, and rs4148913-CHST3. Four of these genes are involved in cell adhesion. Extending our analysis to all well-imputed SNPs of all candidate genes, the strongest association was rs45538638-ABCA3 with CPAP (p = 4.9 × 10-7, FDR = 0.004), an ABC transporter involved in surfactant formation. CONCLUSIONS: Most of the previously reported associations could not be replicated. We found additional support for SNPs in CRP, NUAK1, SELL, VNN2, and ABCA3. Larger studies and meta-analyses are required to corroborate these findings. IMPACT: Larger cohort for improved statistical power to detect genetic associations with bronchopulmonary dysplasia (BPD). Most of the previously reported genetic associations with BPD could not be replicated in this larger study. Among investigated immunological relevant candidate genes, additional support was found for variants in genes CRP, NUAK1, SELL, VNN2, and CHST3, four of them related to cell adhesion. rs45538638 is a novel candidate SNP in reported candidate gene ABC-transporter ABCA3. Results help to prioritize molecular candidate pathomechanisms in follow-up studies.

Apolipoprotein E gene polymorphisms and intraventricular haemorrhage in infants born preterm: a large prospective multicentre cohort study.

AIM: Infants born preterm are at risk of intraventricular haemorrhage (IVH) but individual susceptibility related to genes is not well defined in this vulnerable population. Apolipoprotein genotypes APOE2 and APOE4 increase the hazard of cerebral haemorrhages in adults. We investigated whether APOE is associated with prevalence of IVH and is likely to have a particular genotype. METHOD: In this prospective study, 5075 infants born preterm with genotype APOE3 were compared to 965 (APOE2) and 1912 (APOE4) individuals, to analyse the association between APOE genotype and grade III and IV IVH. We used a logistic regression model including gestational age, antenatal steroid treatment, 5-minute Apgar scores less than 3, intubation, pneumothorax, small for gestational age, multiple birth, sex, and maternal descent as independent factors. RESULTS: The APOE2 (20.1%) and APOE4 (19.8%) genotypes were significantly more prevalent in infants with IVH than in those with the APOE3 haplotype (17.4%) (APOE2: odds ratio [OR] 1.33, 95% confidence interval [CI] 1.00-1.76; APOE4: OR 1.39, 95% CI 1.12-1.74). Infants with two polymorphisms had the highest risk of IVH (8.7%; OR 1.63, 95% CI 1.09-2.45). INTERPRETATION: APOE2 and APOE4 genotypes are relevant risk factors for IVH in infants born preterm. Our findings improve our understanding of the genetic contributions to IVH.

Attenuated PDGF signaling drives alveolar and microvascular defects in neonatal chronic lung disease.

Neonatal chronic lung disease (nCLD) affects a significant number of neonates receiving mechanical ventilation with oxygen-rich gas (MV-O2). Regardless, the primary molecular driver of the disease remains elusive. We discover significant enrichment for SNPs in the PDGF-Rα gene in preterms with nCLD and directly test the effect of PDGF-Rα haploinsufficiency on the development of nCLD using a preclinical mouse model of MV-O2 In the context of MV-O2, attenuated PDGF signaling independently contributes to defective septation and endothelial cell apoptosis stemming from a PDGF-Rα-dependent reduction in lung VEGF-A. TGF-ß contributes to the PDGF-Rα-dependent decrease in myofibroblast function. Remarkably, endotracheal treatment with exogenous PDGF-A rescues both the lung defects in haploinsufficient mice undergoing MV-O2 Overall, our results establish attenuated PDGF signaling as an important driver of nCLD pathology with provision of PDGF-A as a protective strategy for newborns undergoing MV-O2.

Use of analgesic and sedative drugs in VLBW infants in German NICUs from 2003-2010.

UNLABELLED: Very low birth weight (VLBW) infants frequently receive analgesia and/or sedation for painful procedures and mechanical ventilation to avoid negative stress. Yet, concerns remain regarding potential adverse long-term effects of these drugs on VLBW infants' neurocognitive outcome. Recent studies have shown that less invasive surfactant application (LISA) and early nasal CPAP treatment reduce the need for mechanical ventilation and painful procedures. Therefore, these measures might also reduce the application of analgesic and/or sedative drugs in VLBW infants. To evaluate this hypothesis and to identify potential changes in analgesic treatment concepts in recent years, we retrospectively analyzed data on analgesia and sedation, respiratory support, and the method of surfactant application in VLBW infants enrolled in the German Neonatal Network (GNN) trial between 2003 and 2009 (period 1) and compared it with data from infants participating in GNN in 2010 (period 2). In both periods, about one third of all infants were treated with analgesic and/or sedative drugs using a wide variety of substances. The administration of novel drugs such as propofol, sufentanil, or intravenous paracetamol was higher in 2010 (6.7 vs. 12.2 %). Infants who were treated with CPAP only received significantly less analgesic/sedative medication than infants who were mechanically ventilated (12 vs. 65 %, p=<0.001). Similarly, infants treated with LISA received less analgesic or sedative drugs as compared to infants who received surfactant via endotracheal intubation (36 vs. 63 %, p=0.001). CONCLUSION: Although both avoidances of mechanical ventilation and less invasive surfactant application are associated with reduced analgesic or sedative treatment, the percentage of VLBW infants who received analgesia and/or sedation remained unchanged in Germany in recent years.