Neurodevelopmental outcome of bronchopulmonary dysplasia

Survival and Major Morbidity of Extremely Preterm Infants: A Population-Based Study

OBJECTIVES

To assess the rates of mortality and major morbidity among extremely preterm infants born in California and to examine the rates of neonatal interventions and timing of death at each gestational age.

METHODS

A retrospective cohort study of all California live births from 2007 through 2011 linked to vital statistics and hospital discharge records, whose best-estimated gestational age at birth was 22 through 28 weeks. Major morbidities were based on International Classification of Diseases, Ninth Revision, Clinical Modification codes. Survival beyond the first calendar day of life and procedure codes were used to assess attempted resuscitation after birth.

RESULTS

A total of 6009 infants born at 22 through 28 weeks' gestation were included. Survival to 1 year for all live births ranged from 6% at 22 weeks to 94% at 28 weeks. Seventy-three percent of deaths occurred within the first week of life. Major morbidity was present in 80% of all infants, and multiple major morbidities were present in 66% of 22- and 23-week infants. Rates of resuscitation at 22, 23, and 24 weeks were 21%, 64%, and 93%, respectively. Survival after resuscitation was 31%, 42%, and 64% among 22-, 23-, and 24-week infants, respectively. Improved survival was associated with increased birth weight, female sex, and cesarean delivery (P < .01) for resuscitated 22-, 23-, and 24-week infants.

CONCLUSIONS

In a population-based study of extreme prematurity, infants ≤24 weeks' gestation are at highest risk of death or major morbidity. These data can help inform recommendations and decision-making for extremely preterm births.

Caveolin-1 regulates the expression of tight junction proteins during hyperoxia-induced pulmonary epithelial barrier breakdown

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a common complication in preterm infants that involves the downregulation of tight junction (TJ) proteins. However, the mechanism underlying downregulation of the expression of TJ proteins during at the early stages of hyperoxia-induced BPD remains to be understood. Here, we aimed to identify the role of caveolin-1 (Cav-1) in hyperoxia-induced pulmonary epithelial barrier breakdown.

METHODS

First, we established an in vitro pulmonary epithelial barrier models using primary type II alveolar epithelial cells (AEC-II) from newborn rats. AEC-II was assigned to the hyperoxic (85 % O2/5 % CO2) or normoxic (21 % O2/5 % CO2) groups. Second, AEC-II was transfected with Cav-1-siRNA to downregulate Cav-1 under normoxic exposure. Third, AEC-II was transfected with a cDNA encoding Cav-1 to upregulate Cav-1 expression under hyperoxic exposure. Then, expression levels of Cav-1 and TJ proteins were examined by immunofluorescence staining, reverse transcription-polymerase chain reaction, and Western blotting. The TJ structures visualized using a transmission electron microscope, and transepithelial resistance and apparent permeability coefficient of fluorescein isothiocyanate-dextran, which are indicators of barrier function, were measured.

RESULTS

Our data showed that exposure to hyperoxia disrupted the structure and function of the pulmonary epithelial barrier and decreased the ZO-1, occludin, claudin-4, and Cav-1 expression levels. Moreover, Cav-1 knockdown attenuated the expression of the other three genes and disrupted pulmonary epithelial barrier structure and function under normoxic exposure. However, Cav-1 upregulation markedly antagonized the hyperoxia-induced pulmonary epithelial barrier destruction and TJ protein loss.

CONCLUSIONS

This is the first study to present evidence illustrating the novel role of Cav-1 downregulation-mediated TJ protein loss in pulmonary epithelial barrier destruction during BPD.

BPD Following Preterm Birth: A Model for Chronic Lung Disease and a Substrate for ARDS in Childhood

It has been suggested that pediatric acute respiratory distress syndrome (PARDS) may be a different entity, vis-à-vis adult acute respiratory distress syndrome (ARDS), based on its epidemiology and outcomes. A more pediatric-specific definition of PARDS to include the subgroup of patients with underlying lung (and heart) disease has been proposed. Epidemiological data suggest that up to 13% of the children with ARDS have a history of prematurity and/or underlying chronic lung disease. However, the specific contribution of bronchopulmonary dysplasia (BPD), the most common chronic lung disease in infants, to the development of PARDS is not known. BPD leads to damaged lungs with long-term consequences secondary to disordered growth and immune function. These damaged lungs could potentially act as a substrate, which given the appropriate noxious stimuli, can predispose a child to PARDS. Interestingly, similar biomarkers [KL-6, interleukin (IL)-6, IL-8, sICAM-1, angiopoietin-2, and matrix metalloproteinase-8 and -9] of pulmonary injury have been associated both with BPD and ARDS. Recognition of a unique pattern of clinical symptomatology and/or outcomes of PARDS, if present, could potentially be useful for investigating targeted therapeutic interventions.

Bayley-III scales at 12 months of corrected age in preterm infants: Patterns of developmental performance and correlations to environmental and biological influences

BACKGROUND AND AIMS

Premature infants are at high risk for neurodevelopmental impairment (NDI) even in the absence of known brain complications of prematurity. Evaluation of the effectiveness of therapeutic interventions in association to neurodevelopmental outcome is required to improve or prevent the neurodevelopmental consequences of prematurity. The Bayley-III is currently the most commonly applied measurement tool for assessing early development both in clinical practice and research settings.

OBJECTIVE

To evaluate the relationship between known risk factors and early performance on the Bayley Scales of Infant Development-Third Edition at 12 months adjusted age in premature infants.

METHODS

Prospective study in a cohort of premature infants with gestational age ≤32 weeks, who underwent comprehensive developmental assessment using the five domains of Bayley Scales, cognitive, language, motor, social emotional and adaptive behavior at 12 months corrected age. Developmental scores were evaluated in relation to environmental influences, therapeutic interventions or practices and complications of prematurity.

RESULTS

Composite and Subscale scores for the cognitive, language and motor scales were below the 50th percentile, with no significant differences among them. Scores for the social-emotional and adaptive behavior, which are derived from the parent-report questionnaires, were near the average and significantly higher than the scores derived by the examiners. Multiple regression analyses showed that blood transfusions, apart from severely abnormal head ultrasound, gender, being small for gestational age and duration of invasive mechanical ventilation and oxygen administration were consistently related to neurodevelopmental outcome.

CONCLUSIONS

Bayley-III assessments are important for getting early information about development following premature birth. Parents may overestimate children's performance. Neurodevelopmental outcome is related to several environmental, biological or medical conditions associated with prematurity. Adoption of therapeutic strategies targeting known neonatal risk factors could positively affect neurodevelopmental outcome.

Neonatal bronchopulmonary dysplasia increases neuronal apoptosis in the hippocampus through the HIF-1α and p53 pathways

Neonatal bronchopulmonary dysplasia (BPD) might lead to an increased risk for brain injury. The present study aims to investigate the effects of neonatal BPD on neuronal apoptosis in the hippocampus and cognitive function and to explore the underlying mechanisms. The results revealed that BPD model rat pups exhibited more apoptotic cells in the hippocampus and longer escape latencies in the Morris maze test. Both the caspase-dependent and caspase-nondependent signal pathways were activated. Further examinations showed an elevated p53 level by BPD via HIF-1α induction, while the caspase-3 in the hippocampus was suppressed by both HIF-1α and p53 inhibitor. These findings suggested that neonatal BPD caused impaired cognitive function and neuron apoptosis in hippocampus via p53 and HIF-1α. Although the precise mechanism requires further investigation, this study provided new evidence for and an explanation of the impaired CNS developmental outcomes of BPD.

MicroRNA expression profiles and target prediction in neonatal Wistar rat lungs during the development of bronchopulmonary dysplasia

In this study, we investigated the mechanisms through which microRNAs (miRNAs or miRs) regulate lung development after birth, as well as the role of miRNAs in the development of bronchopulmonary dysplasia (BPD). For this purpose, a total of 90 neonatal Wistar rats were randomly and equally assigned to either a model group or a control group. On postnatal days 3, 7 and 14, the lung tissues were collected for histological analysis to determine morphological changes. The expression levels of proliferating cell nuclear antigen (PCNA) and platelet endothelial cell adhesion molecule-1 (PECAM-1, also known as CD31) were measured by RT-qPCR and western blot analysis. A miRCURY™ LNA array was employed to screen for differentially expressed miRNAs, and the possible target genes of those miRNAs were predicted. Our results revealed that, compared with the control group, the following changes induced by hyperoxia were observed in the model group over time: a decrease in the number, but an increase in the size of the alveoli, and a decrease in the number of secondary septa formed. In the model group, from postnatal days 3–14, the mRNA and protein expression levels of PCNA and CD31 were significantly lower than those in the control group. The differentially expressed miRNAs between the 2 groups were identified on days 3, 7 and 14 after birth. Possible target genes were identified for 32 differentially expressed miRNAs. Taken together, these findings suggest that during the development of BPD, an alveolarization disorder with microvascular dysplasia co-exists with the differential expression of certain miRNAs during the different stages of alveolar development in a neonatal rat model of hyperoxia-induced BPD. This indicates that miRNAs may participate in the occurrence and development of BPD.

Hyperoxia stimulates the transdifferentiation of type II alveolar epithelial cells in newborn rats

Supplemental oxygen treatment in preterm infants may cause bronchopulmonary dysplasia (BPD), which is characterized by alveolar simplification and vascular disorganization. Despite type II alveolar epithelial cell (AEC II) damage being reported previously, we found no decrease in the AEC II-specific marker, surfactant protein C (SP-C), in the BPD model in our previous study. We thus speculated that AEC II injury is not a unique mechanism of BPD-related pulmonary epithelial repair dysfunction and that abnormal transdifferentiation can exist. Newborn rats were randomly assigned to model (85% oxygen inhalation) and control groups (room air inhalation). Expressions of AEC I (aquaporin 5, T1α) and AEC II markers (SP-C, SP-B) were detected at three levels: 1) in intact lung tissue, 2) in AEC II isolated from rats in the two groups, and 3) in AEC II isolated from newborn rats, which were further cultured under either hyperoxic or normoxic conditions. In the model group, increased AEC I was observed at both the tissue and cell level, and markedly increased transdifferentiation was observed by immunofluorescent double staining. Transmission electron microscopy revealed morphological changes in alveolar epithelium such as damaged AECs, a fused air-blood barrier structure, and opened tight junctions in the model group. These findings indicate that transdifferentiation of AECs is not suppressed but rather is increased under hyperoxic treatment by compensation; however, such repair during injury cannot offset pulmonary epithelial air exchange and barrier dysfunction caused by structural damage to AECs.

Long-term alpha-tocopherol supplements may improve mental development in extremely low birthweight infants

AIM

Methods to improve the mental development of extremely low birthweight (ELBW) children are currently lacking. We assessed the effects of long-term supplementation of alpha-tocopherol on the neurological development of 259 school-aged ELBW children.

METHODS

Extremely low birthweight participants were divided into three groups: group A with no alpha-tocopherol supplementation (n = 121); group B with the supplementation for <6 months (n = 104) and group C with the supplementation for more than 6 months (n = 34). We analysed the participants' data at birth and between the ages of one-and-a-half to 8 years and evaluated potential factors associated with intellectual disabilities.

RESULTS

Children from group C had the best outcome. The groups' mean gestational weeks and mean ventilator days were as follows: 27.5 weeks, 16.1 days (group A); 25.7 weeks, 41.7 days (group B); and 25.1 weeks, 75.5 days (group C). Multivariate regression analysis revealed that the odds ratios for impaired mental development at 8 years were 1.5 in group B and 0.19 (p = 0.017) in group C, compared with 1.0 in group A. The association between the duration of alpha-tocopherol administration and performance intelligence quotient (IQ) was dose dependent (p = 0.03).

CONCLUSION

Long-term supplementation of alpha-tocopherol appeared to improve mental development, in particular, performance IQ, in school-aged ELBW children.

Acute Neonatal Respiratory Failure

Acute respiratory failure requiring assisted ventilation is one of the most common reasons for admission to the neonatal intensive care unit. Respiratory failure is the inability to maintain either normal delivery of oxygen to the tissues or normal removal of carbon dioxide from the tissues. It occurs when there is an imbalance between the respiratory workload and ventilatory strength and endurance. Definitions are somewhat arbitrary but suggested laboratory criteria for respiratory failure include two or more of the following: PaCO₂ > 60 mmHg, PaO₂ < 50 mmHg or O₂ saturation <80 % with an FiO₂ of 1.0 and pH < 7.25 (Wen et al. 2004).

Epithelial-mesenchymal transitions in bronchopulmonary dysplasia of newborn rats

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a major threat to the health of premature infants yet its pathogenesis is not fully understood. Epithelial-mesenchymal transition (EMT) of lung epithelial cells may lead to BPD.

OBJECTIVE

To investigate the potential occurrence of EMT in a newborn rat model of BPD.

METHODS

Newborn rats were exposed to a hyperoxic environment within 12 hr of birth. Lung tissue and isolated alveolar epithelial type II cells (AT2 cells) were collected on Days 1, 3, 7, 14, and 21 after hyperoxic exposure. Pathological changes in lung tissue, alveolar development, ultrastructural changes in AT2 cells, co-expression of surfactant associated surfactant protein C (SPC), and α-smooth muscle actin (α-SMA) were investigated. The relative expression of SPC, α-SMA, E-cadherin, and N-cadherin were investigated in lung tissue and isolated AT2 cells.

RESULTS

In lung tissue, alveolar development was attenuated from Day 7 onwards in the BPD model group; co-expression of SPC and α-SMA and ultrastructural changes typical of EMT were observed in AT2 cells from rats in the BPD group. SPC and α-SMA expression levels were higher in tissue samples from the BPD group than in control samples. Beginning on Day 7, evidence of a switch from E-cadherin to N-cadherin expression was observed in BPD lung tissue sample and in isolated AT2 cells.

CONCLUSION

EMT of AT2 cells occurred in the hyperoxia-induced newborn rat BPD model and resulted in attenuated alveolar development as a portion of the myofibroblasts accumulated in the lung originated from AT2 cells via EMT.

Individual course of cranial symmetry and proportion in preterm infants up to 6 months of corrected age

INTRODUCTION

A significant proportion of preterm infants have dolichocephaly and/or deformational plagiocephaly (DP) at term equivalent age. However, quantitative data on the clinical course after discharge is limited in these infants.

AIMS

To quantify the individual course of cranial symmetry and proportion in infants born <32 gestational weeks up to six months of corrected age (CA) and to investigate, whether measurements at discharge predict subsequent cranial deformations.

METHODS

A total of 56 infants were examined at discharge, three and six months of CA. Cranial proportion and symmetry were quantified using a 3D laser scan method. Classification and prevalence data were obtained using age related reference values. Predictive value of DP at discharge regarding subsequent deformation was evaluated.

RESULTS

Cranial Vault Asymmetry Index was 3.9% at discharge, 4.5% at three months and 3.7% at six months of CA. Prevalence of DP was 34% at discharge, 46% at three months and 27% at six months. Cranial Index was 71.4% at discharge and constantly increased over the examination period. Prevalence of dolichocephaly was high at discharge (77%) and subsequently decreased. While severe DP at discharge was predictive for a persistent deformation (PPV 0.78), 46% of infants without DP at discharge developed DP by six months of CA.

DISCUSSION

Despite a high prevalence at discharge, the decreased prevalence of DP and dolichocephaly at six months of CA suggests an optimistic course. However, changes in head shape are hardly predictable for the individual infant. Thus, an accurate quantification should be part of neonatal follow-up programs.

A systematic review of randomized controlled trials for the prevention of bronchopulmonary dysplasia in infants

OBJECTIVE

Bronchopulmonary dysplasia (BPD) is the most common cause of pulmonary morbidity in premature infants and is associated with life-long morbidities. Developing drugs for the prevention of BPD would improve public health. We sought to determine characteristics of favorable randomized controlled trials (RCTs) of drugs for BPD prevention.

STUDY DESIGN

We searched MEDLINE and EMBASE from 1992 to 2014 using the MeSH terms 'BPD' and 'respiratory distress syndrome, newborn'. We included a Cochrane Library search to ensure inclusion of all available RCTs. We identified RCTs with BPD as a primary or secondary outcome and determined the definition of BPD used by the study. We determined whether a phase I or phase II study-to determine drug safety, efficacy or optimal dose-was performed before the RCT. Finally, we searched the Cochrane Library for meta-analyses for each drug and used the results of available meta-analyses to define a favorable versus unfavorable RCT.

RESULT

We identified 2026 articles; 47 RCTs met our inclusion criteria encompassing 21 drugs; 5 of the drugs reduced the incidence of BPD. We found data from phase I or II studies for 16 of the drugs, but only 1 demonstrated a reduction of BPD.

CONCLUSION

The majority of the drugs studied in RCTs failed to reduce the incidence of BPD. Performing early-phase studies before phase III trials might provide necessary information on drugs and drug doses capable of preventing BPD, thus informing the development of future RCTs.

Omega-3 long-chain polyunsaturated fatty acids for extremely preterm infants: a systematic review

BACKGROUND AND OBJECTIVE

Omega-3 long chain polyunsaturated fatty acid (LCPUFA) exposure can be associated with reduced neonatal morbidities. We systematically review the evidence for the benefits of omega-3 LCPUFAs for reducing neonatal morbidities in extremely preterm infants.

METHODS

Data sources were PubMed, Embase, Center for Reviews and Dissemination, and the Cochrane Register of Controlled Trials. Original studies were selected that included infants born at <29 weeks' gestation, those published until May 2013, and those that evaluated the relationship between omega-3 LCPUFA supplementation and major adverse neonatal outcomes. Data were extracted on study design and outcome. Effect estimates were pooled.

RESULTS

Of the 1876 studies identified, 18 randomized controlled trials (RCTs) and 6 observational studies met the defined criteria. No RCT specifically targeted a population of extremely preterm infants. Based on RCTs, omega-3 LCPUFA was not associated with a decreased risk of bronchopulmonary dysplasia in infants overall (pooled risk ratio [RR] 0.97, 95% confidence interval [CI] 0.82-1.13], 12 studies, n = 2809 infants); however, when considering RCTs that include only infants born at ≤32 weeks' gestation, a trend toward a reduction in the risk of bronchopulmonary dysplasia (pooled RR 0.88, 95% CI 0.74-1.05, 7 studies, n = 1156 infants) and a reduction in the risk of necrotizing enterocolitis (pooled RR 0.50, 95% CI 0.23-1.10, 5 studies, n = 900 infants) was observed with LCPUFA.

CONCLUSIONS

Large-scale interventional studies are required to determine the clinical benefits of omega-3 LCPUFA, specifically in extremely preterm infants, during the neonatal period.

Ascorbylperoxide from parenteral nutrition induces an increase of redox potential of glutathione and loss of alveoli in newborn guinea pig lungs

Background

Bronchopulmonary dysplasia is one of the main complications associated with extreme prematurity. Oxidative stress is suspected to be a trigger event of this lung disease, which is characterized by impaired alveolar development. Peroxides, mainly ascorbylperoxide and H₂O₂, are known contaminant of parenteral nutrition. We hypothesize that these oxidant molecules induce bronchopulmonary dysplasia development. The aim was to determine if the infusion of ascorbylperoxide, whether in presence or absence of H₂O₂, is associated with oxidative stress, apoptosis and loss of alveoli in the lungs of newborn guinea pigs.

Method

Three-day-old guinea pigs received parenteral solutions containing 0, 20, 60 or 180 µM ascorbylperoxide in the presence or not of 350 µM H₂O₂ (concentrations similar to those measured in parenteral nutrition). After 4 days, the lungs were collected for determination of glutathione's redox potential, caspase-3 activation (an apoptosis marker), alveolarization index (by histology), activation of Nrf2 and NF?B (biological markers of oxidative stress), and IL-6 and PGJ₂ levels (markers of NF?B activation). Groups were compared by ANOVA, p < 0.05.

Results

Loss of alveoli was associated with ascorbylperoxide in a dose-dependent manner, without an influence of H₂O₂. The dose-dependent activation of caspase-3 by ascorbylperoxide was lower in the presence of H₂O₂. Ascorbylperoxide induced an increase of redox potential in a dose-dependent manner, which reached a plateau in presence of H₂O₂. Nrf2 and NF?B were activated by H₂O₂ but not by ascorbylperoxide.

Conclusion

Results suggest that ascorbylperoxide, generated in parenteral nutrition, is involved in the development of bronchopulmonary dysplasia, independently of the increase of the redox potential. This study underlines the importance of developing a safer formulation of parenteral nutrition.

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Oxidative stress is suspected to induce bronchopulmonary dysplasia.

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We investigate the role of ascorbylperoxide contaminating parenteral nutrition.

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This molecule induces oxidation of redox potential, apoptosis and loss of alveoli.

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The alveolar loss is independent of the redox potential.

Need for supplemental oxygen at discharge in infants with bronchopulmonary dysplasia is not associated with worse neurodevelopmental outcomes at 3 years corrected age

OBJECTIVES

To determine if chronic oxygen dependency (discharge home on supplemental oxygen) in children with bronchopulmonary dysplasia (BPD; defined as requirement for supplemental O2 at 36 weeks postmenstrual age) predicts neurodevelopmental disability rates and growth outcomes at 36 months corrected age (CA).

STUDY DESIGN

Longitudinal cohort study.

SETTING

Southern Alberta regional center located at high altitude.

PARTICIPANTS

Preterm infants weighing ≤1250 grams with no BPD, BPD, and BPD with chronic oxygen dependency.

MAIN OUTCOME MEASURES

Neurodevelopmental and growth outcomes.

RESULTS

Of 1563 preterm infants admitted from 1995-2007, 1212 survived. Complete follow-up data were available for 1030 (85%) children. Children in BPD and BPD with chronic oxygen dependency groups had significantly lower birth weights, gestational ages, prolonged mechanical ventilation and oxygen supplementation and received more postnatal steroids, compared to those without BPD. Children with BPD and BPD with chronic oxygen dependency were more likely to be below the 5th centile in weight and height compared to those without BPD but there was little difference between the BPD and BPD with chronic oxygen dependency groups. After controlling for confounding variables, children who had BPD and BPD with chronic oxygen dependency had higher odds of neurodevelopmental disability compared to those without BPD [OR (odds ratio) 1.9 (95%CI 1.1 to 3.5) and OR 1.8 (1.1 to 2.9), respectively], with no significant difference between BPD and BPD with chronic oxygen dependency [OR 0.9 (95% CI 0.6 to 1.5)].

CONCLUSIONS

BPD and BPD with chronic oxygen dependency in children predicts abnormal neurodevelopmental outcomes at 36 months CA. However, the neurodevelopmental disability rates were not significantly higher in BPD with chronic oxygen dependency children compared to children with BPD only. Compared to those without BPD, growth is impaired in children with BPD and BPD with chronic oxygen dependency, but no difference between the latter two groups.

Postnatal inflammation in the pathogenesis of bronchopulmonary dysplasia

Exposure to hyperoxia, invasive mechanical ventilation, and systemic/local sepsis are important antecedents of postnatal inflammation in the pathogenesis of bronchopulmonary dysplasia (BPD). This review will summarize information obtained from animal (baboon, lamb/sheep, rat and mouse) models that pertain to the specific inflammatory agents and signaling molecules that predispose a premature infant to BPD.

Glutathionylated γG and γA subunits of hemoglobin F: a novel post-translational modification found in extremely premature infants by LC-MS and nanoLC-MS/MS

Oxidative stress plays an important role in the development of various disease processes and is a putative mechanism in the development of bronchopulmonary dysplasia, the most common complication of extreme preterm birth. Glutathione, a major endogenous antioxidant and redox buffer, also mediates cellular functions through protein thiolation. We sought to determine if post-translational thiol modification of hemoglobin F occurs in neonates by examining erythrocyte samples obtained during the first month of life from premature infants, born at 23 0/7 - 28 6/7 weeks gestational age, who were enrolled at our center in the Prematurity and Respiratory Outcomes Program (PROP). Using liquid chromatography-mass spectrometry (LC-MS), we report the novel finding of in vivo and in vitro glutathionylation of γG and γA subunits of Hgb F. Through tandem mass spectrometry (nanoLC-MS/MS), we confirmed the adduction site as the Cys-γ94 residue and through high-resolution mass spectrometry determined that the modification occurs in both γ subunits. We also identified glutathionylation of the β subunit of Hgb A in our patient samples; we did not find modified α subunits of Hgb A or F. In conclusion, we are the first to report that glutathionylation of γG and γA of Hgb F occurs in premature infants. Additional studies of this post-translational modification are needed to determine its physiologic impact on Hgb F function and if sG-Hgb is a biomarker for clinical morbidities associated with oxidative stress in premature infants.

Social-emotional delays at 2 years in extremely low gestational age survivors: correlates of impaired orientation/engagement and emotional regulation

BACKGROUND

Premature infants are less socially and emotionally competent at school age than infants born at term.

AIMS

To evaluate the correlates of social and emotional delays at 2 years of age among prematurely born children.

STUDY DESIGN

This is a prospective cohort study.

SUBJECTS

904 children born at <28 weeks gestation during 2002-2004 and enrolled in the ELGAN study who survived until age 2 years and returned for a developmental assessment.

OUTCOME MEASURES

The Bayley Behavior Rating Scale (BRS), a neurological examination, and the Bayley Scales of Infant Development II (BSID-II).

RESULTS

Fully 31% of children had a non-optimal (14%) or questionable (17%) (NO/Q) BRS score for Emotional Regulation (ER), and 27% had a non-optimal (13%) or questionable (14%) score for Orientation/Engagement (O/E). Children with NO/Q scores on ER and O/E were more likely than others to have MDI and PDI scores <70 and be unable to walk. Antecedents of NO/Q OE scores included multi-fetal pregnancy, while antecedents of NO/Q scores for both ER and O/E included indicators of socioeconomic disadvantage, and male sex.

CONCLUSIONS

Over 25% of children born extremely premature exhibit socio-emotional delays during developmental assessment at age 2 years. Antecedents of these delays include sociodemographic characteristics, as well as those common antecedents of other impairments commonly observed among extremely preterm infants.

Clinical course of asymmetric motor performance and deformational plagiocephaly in very preterm infants

OBJECTIVES

To describe the clinical courses of positional preference and deformational plagiocephaly up to 6 months corrected age (CA) in infants born at gestational age <30 weeks or birth weight <1000 g, and to explore predictive factors for the persistence of these phenomena.

STUDY DESIGN

A total of 120 infants were examined 3 times each. The presence of deformational plagiocephaly and a score of 0-6 on an asymmetry performance scale served as outcome measures at 6 months CA. Predictive factors were determined using regression analysis.

RESULTS

The prevalence of a positional preference of the head was 65.8% (79 of 120) at term-equivalent age (TEA) and 36.7% (44 of 120) at 3 months CA and that of deformational plagiocephaly was 30% (36 of 120) at TEA and 50% (60 of 120) at 3 months CA. At 6 months CA, 15.8% of the infants (19 of 120) scored ≥ 2 of a possible 6 on the asymmetry performance scale and 23.3% (28 of 120) had deformational plagiocephaly. Sleeping in the supine position was predictive of an asymmetric motor performance at 6 months CA. Chronic lung disease and/or slow gross motor maturation at 3 months CA predicted the persistence of deformational plagiocephaly.

CONCLUSION

Infants born very preterm may develop deformational plagiocephaly. A positional preference of the head at TEA seems to be a normal aspect of these infants' motor repertoire, with limited ability to predict persistence of an asymmetric motor performance. The decreased prevalence of deformational plagiocephaly between 3 and 6 months CA indicates an optimistic course. Infants with a history of chronic lung disease and/or slow gross motor maturation merit timely intervention.

Specific early vulnerability of high-order executive function to focal brain lesions and long-term impact on educational persistence: Sparing of incidental episodic memory

OBJECTIVE

We investigated mental functions expected to remain impaired or not ain adulthood following childhood-onset brain lesions.

METHODS

Thirty unilaterally lesioned young adults were tested a decade after lesion onset with an effort-demanding complex executive function (EF) task as well as a task of incidental declarative retrospective episodic recognition memory (IRM). Thirty neurotypical participants were also tested.

RESULTS

The EF task was significantly impaired in the lesion group and significantly more so than the IRM task. Regarding the lesioned cases, performance on EF, but not IRM, was significantly positively correlated with long-term educational persistence (EP). Both EF and EP but not IRM were significantly positively correlated with the age of onset of the lesion. Severity of neurological impairment was unrelated to any variable.

CONCLUSION

Mental abilities acquired through early schooling remain impaired into adulthood when early schooling is disturbed, not everyday memory which does not depend on schooling.

Assessing independency in daily activities in very preterm children at preschool age

This study investigates whether very low birth weight (VLBW) preschoolers experience disability in daily activities and what the risk factors for disability in daily activities are. The Dutch Pediatric Evaluation of Disability Inventory (PEDI-NL) was used to detect disability in daily activities in 143 VLBW children without cerebral palsy (CP) at 44 months of corrected age (CA). Data from the psychomotor-developmental index (PDI) and the mental developmental index (MDI) of the Bayley Scales of Infant Development II (BSID II) at 24 months CA, and data relating to perinatal and socio-economic status were available. Disability in daily activities was found in 27 (19%) VLBW children without CP. High frequencies of disability were found in 19 (13%) children on the mobility domain and in 12 (8%) children on the social functioning domain. The multiple logistic regression analyses showed that low BSID II outcomes (<2 SD) were risk factors for disability in the mobility domain, but not for disability in the social functioning domain. The predictive value of the BSID II outcomes is moderate, 46% of the VLBW children with a low PDI and 44% with a low MDI developed a disability in the mobility domain. This study showed a higher frequency of disability in daily activities in VLBW preschoolers compared to term born peers. Therefore, it is suggested to assess VLBW children's performance of daily activities before they start school.

Predictive value of the Bayley scales of infant development on development of very preterm/very low birth weight children: a meta-analysis

BACKGROUND AND AIMS

The Bayley scales of infant development (BSID) is the most widely used measure to assess neurodevelopment of very preterm (gestational age ≤32 weeks) and very low birth weight (VLBW, ≤1500 g) infants in the first three years of life. This meta-analysis determines the predictive value of the mental developmental index (MDI) and the psychomotor developmental index (PDI)/motor composite, collectively referred to as Bayley motor scale, of the BSID-I, -II and Bayley-III for later cognitive and motor functioning in very preterm/VLBW children.

METHODS

Cochrane Library, PubMed, PsychINFO and CINAHL were searched for English-language peer-reviewed studies published before March 2013. Studies were included if they reported odds ratios or correlations between the MDI or Bayley motor scale scores obtained in the first three years of life, and standardized cognitive or motor assessment obtained later in life in very preterm/VLBW children. Meta-analytic methods were applied to aggregate available data.

RESULTS

A total of 16 studies met inclusion criteria. Across 14 studies (n=1330 children), MDI scores were strongly predictive for later cognitive functioning, r=0.61 (95% CI: 0.57-0.64), explained variance 37%, p<.001. The relationship between MDI scores and later cognitive function was not mediated by birth weight (p=.56), gestational age (p=.70), and time interval between assessments (p=.55). Across five studies (n=555 children), Bayley motor scale scores were moderately predictive for later motor function, r=0.34 (95% CI: 0.26-0.42), explained variance 12%, p<.001.

CONCLUSIONS

In very preterm/VLBW children, MDI scores explain 37% of the variance in later cognitive functioning, whereas Bayley motor scale scores explain 12% of later motor function. Thus a large proportion of the variance remains unexplained, underlining the importance of enhancing prediction of developmental delay in very preterm children.

Pulmonary hypertension in bronchopulmonary dysplasia

Pulmonary hypertension (PH) is a common complication of neonatal respiratory diseases, including bronchopulmonary dysplasia (BPD), and recent studies have increased awareness that PH worsens the clinical course, morbidity and mortality of BPD. Recent evidence indicates that up to 18% of all extremely low-birth-weight infants will develop some degree of PH during their hospitalization, and the incidence rises to 25-40% of the infants with established BPD. Risk factors are not yet well understood, but new evidence shows that fetal growth restriction is a significant predictor of PH. Echocardiography remains the primary method for evaluation of BPD-associated PH, and the development of standardized screening timelines and techniques for identification of infants with BPD-associated PH remains an important ongoing topic of investigation. The use of pulmonary vasodilator medications, such as nitric oxide, sildenafil, and others, in the BPD population is steadily growing, but additional studies are needed regarding their long-term safety and efficacy.

Bronchopulmonary dysplasia and neurodevelopmental outcome in extremely preterm neonates

We tested the hypothesis that the use of supplemental oxygen (sO2) at discharge from the NICU in extremely preterm neonates is associated with a greater risk of neurodevelopmental impairment (NDI) at 18 months corrected gestational age (CGA) than the risk of NDI of those neonates discharged in room air. Four hundred twenty-four charts were retrospectively reviewed from infants born at <27 weeks and transferred to Nationwide Children's Hospital from December 1, 2004 to June 14, 2010. Use of sO2 was evaluated on day of life (dol) 28, at 36 weeks post-menstrual age (PMA), and at discharge. Logistic regression was used to identify postnatal risk factors associated with sO2 at discharge and NDI. At dol 28, 96 % of surviving patients received sO2, and therefore had bronchopulmonary dysplasia (BPD) by definition from a National Institutes of Child Health and Human Development workshop. At 36 weeks PMA, 89 % continued on sO2 (moderate/severe BPD), and at discharge, 74 % continued on sO2. When factors associated with NDI were examined, the need for mechanical ventilation ≥28 days (adjOR = 3.21, p = 0.01), grade III-IV intraventricular hemorrhage (IVH) (adjOR = 4.61, p < 0.01), and discharge at >43 weeks PMA (adjOR = 2.12, p = 0.04) were the strongest predictors of NDI at 18 months CGA. There was no difference in Bayley Scales of Infant Development, third edition composite scores between patients with no/mild BPD and patients with moderate/severe BPD (cognitive p = 0.60, communication p = 0.53, motor p = 0.19) or those scores between patients on and off oxygen at discharge (cognitive p = 0.58, communication p = 0.70, motor p = 0.62).

CONCLUSIONS

The need for sO2 at discharge is not associated with an increased risk of NDI in these patients. The strongest predictors of poor neurodevelopmental outcome in this population were prolonged positive pressure support, grade III-IV IVH, and discharge at >43 weeks PMA.

Neurodevelopmental impairment following neonatal hyperoxia in the mouse

Extremely premature infants are often exposed to supra-physiologic concentrations of oxygen, and frequently have hypoxemic episodes. These preterm infants are at high risk (~40%) for neurodevelopmental impairment (NDI) even in the absence of obvious intracranial pathology such as intraventricular hemorrhage or periventricular leukomalacia. The etiology for NDI has not been determined, and there are no animal models to simulate neurodevelopmental outcomes of prematurity. Our objectives were to develop and characterize a mouse model to determine long-term effects of chronic hypoxia or hyperoxia exposure on neurodevelopment. Newborn C57BL/6 mice were exposed to hypoxia (12% O(2)) or hyperoxia (85% O(2)) from postnatal days 1 to 14 and then returned to air. At 12-14 weeks of age, neurobehavioral assessment (Water Maze test, Novel Object Recognition test, Open Field test, Elevated Plus Maze, and Rotarod test) was performed, followed by MRI and brain histology. Neurobehavioral testing revealed that hyperoxia-exposed mice did poorly on the water maze and novel object recognition tests compared to air-exposed mice. MRI demonstrated smaller hippocampi in hyperoxia- and hypoxia-exposed mice with a greater reduction in hyperoxia-exposed mice, including a smaller cerebellum in hyperoxia-exposed mice. Brain histology showed reduced CA1 and CA3 and increased dentate gyral width in hippocampus. In conclusion, neonatal hyperoxia in mice leads to abnormal neurobehavior, primarily deficits in spatial and recognition memory, associated with smaller hippocampal sizes, similar to findings in ex-preterm infants. This animal model may be useful to determine mechanisms underlying developmental programming of NDI in preterm infants, and for evaluation of therapeutic strategies.

Can the early condition at admission of a high-risk infant aid in the prediction of mortality and poor neurodevelopmental outcome? A population study in Australia

AIM

The aim of this article was to evaluate the Revised Clinical Risk Index for Babies' (CRIB-II) severity of illness score as a predictor of moderate to severe functional disability (FD) in very premature infants.

METHODS

Population study of infants born <29 weeks' gestation cared for in all Neonatal Intensive Care Unit in New South Wales and the Australian Capital Territory between 1998 and 2003. FD at 2-3 years corrected age was defined as developmental delay (quotient < 2 standard deviation), non-ambulatory cerebral palsy (needing aids to walk), blindness (acuity <6/60 in better eye) or deafness (hearing aids). Sensitivity and specificity of CRIB-II scores to predict FD were performed by receiver operating characteristic curve analysis.

RESULTS

Of study population of 2210, 480 (21.7%) died before hospital discharge. Among 1328 infants assessed, 217 (16.3%) had FD, 109 (8.2%) developmental delay, 75 (5.6%) cerebral palsy and 54 (4.1%) blindness or deafness. CRIB-II performed significantly better than gestation or birthweight (BW) alone in predicting mortality (area under the curve (AUC) ± standard error 0.83 ± 0.01, vs. 0.78 ± 0.01 and 0.76 ± 0.01, respectively). CRIB-II scores were significantly higher in FD than non-FD children (11.9 ± 2.9 vs. 10.1 ± 2.6), but the AUC for CRIB-II (0.68 ± 0.02) did not significantly differ from that of gestation (0.65 ± 0.02) and BW (0.65 ± 0.02).

CONCLUSION

CRIB-II improved prediction of mortality but did not perform better than gestational age or BW in predicting FD. We would caution clinicians against using the infant's condition at admission to predict long-term outcome.

Outcomes of extremely low birth weight infants with bronchopulmonary dysplasia: impact of the physiologic definition

AIMS

We compared neurodevelopmental outcomes of extremely low birth weight (ELBW) infants with and without bronchopulmonary dysplasia (BPD), using the physiologic definition.

STUDY DESIGN

ELBW (birth weights<1000 g) infants admitted to the Neonatal Research Network centers and hospitalized at 36 weeks postmenstrual age (n=1189) were classified using the physiologic definition of BPD. Infants underwent Bayley III assessment at 18-22 months corrected age. Multivariable logistic regression was used to determine the association between physiologic BPD and cognitive impairment (score<70).

RESULTS

BPD by the physiologic definition was diagnosed in 603 (52%) infants, 537 of whom were mechanically ventilated or on FiO(2)>30% and 66 who failed the room air challenge. Infants on room air (n=505) and those who passed the room air challenge (n=51) were classified as "no BPD" (n=556). At follow up, infants with BPD had significantly lower mean weight and head circumference. Moderate to severe cerebral palsy (7 vs. 2.1%) and spastic diplegia (7.8 vs. 4.1%) and quadriplegia (3.9 vs. 0.9%) phenotypes as well as cognitive (12.8 vs. 4.6%) and language scores<70 (24.2 vs. 12.3%) were significantly more frequent in those with BPD compared to those without BPD. BPD was independently associated (adjusted OR 2.4; 95% CI 1.40-4.13) with cognitive impairment.

CONCLUSIONS

Rates of adverse neurodevelopmental outcomes in early childhood were significantly higher in those with BPD. BPD by the physiologic definition was independently associated with cognitive impairment using Bayley Scales III. These findings have implications for targeted post-discharge surveillance and early intervention.

Missed opportunities in the referral of high-risk infants to early intervention

OBJECTIVE

Using a statewide population-based data source, we describe current neonatal follow-up referral practices for high-risk infants with developmental delays throughout California.

METHODS

From a cohort analysis of quality improvement data from 66 neonatal follow-up programs in the California Children's Services and California Perinatal Quality Care Collaborative High-Risk Infant Follow-Up Quality of Care Initiative, 5129 high-risk infants were evaluated at the first visit between 4 and 8 months of age in neonatal follow-up. A total of 1737 high-risk infants were evaluated at the second visit between 12 and 16 months of age. We calculated referral rates in relation to developmental status (high versus low concern) based on standardized developmental testing or screening.

RESULTS

Among infants with low concerns (standard score >70 or passed screen) at the first visit, 6% were referred to early intervention; among infants with high concerns, 28% of infants were referred to early intervention. Even after including referrals to other (private) therapies, 34% infants with high concerns did not receive any referrals. These rates were similar for the second visit.

CONCLUSIONS

In spite of the specialization of neonatal follow-up programs to identify high-risk infants with developmental delays, a large proportion of potentially eligible infants were not referred to early intervention.

Hyperoxia disrupts pulmonary epithelial barrier in newborn rats via the deterioration of occludin and ZO-1

Background

Prolonged exposure to hyperoxia in neonates can cause hyperoxic acute lung injury (HALI), which is characterized by increased pulmonary permeability and diffuse infiltration of various inflammatory cells. Disruption of the epithelial barrier may lead to altered pulmonary permeability and maintenance of barrier properties requires intact epithelial tight junctions (TJs). However, in neonatal animals, relatively little is known about how the TJ proteins are expressed in the pulmonary epithelium, including whether expression of TJ proteins is regulated in response to hyperoxia exposure. This study determines whether changes in tight junctions play an important role in disruption of the pulmonary epithelial barrier during hyperoxic acute lung injury.

Methods

Newborn rats, randomly divided into two groups, were exposed to hyperoxia (95% oxygen) or normoxia for 1–7 days, and the severity of lung injury was assessed; location and expression of key tight junction protein occludin and ZO-1 were examined by immunofluorescence staining and immunobloting; messenger RNA in lung tissue was studied by RT-PCR; transmission electron microscopy study was performed for the detection of tight junction morphology.

Results

We found that different durations of hyperoxia exposure caused different degrees of lung injury in newborn rats. Treatment with hyperoxia for prolonged duration contributed to more serious lung injury, which was characterized by increased wet-to-dry ratio, extravascular lung water content, and bronchoalveolar lavage fluid (BALF):serum FD4 ratio. Transmission electron microscopy study demonstrated that hyperoxia destroyed the structure of tight junctions and prolonged hyperoxia exposure, enhancing the structure destruction. The results were compatible with pathohistologic findings. We found that hyperoxia markedly disrupted the membrane localization and downregulated the cytoplasm expression of the key tight junction proteins occludin and ZO-1 in the alveolar epithelium by immunofluorescence. The changes of messenger RNA and protein expression of occludin and ZO-1 in lung tissue detected by RT-PCR and immunoblotting were consistent with the degree of lung injury.

Conclusions

These data suggest that the disruption of the pulmonary epithelial barrier induced by hyperoxia is, at least in part, due to massive deterioration in the expression and localization of key TJ proteins.

The outcome of ELBW infants treated with NCPAP and InSurE in a resource-limited institution

BACKGROUND AND OBJECTIVE

Nasal continuous positive airway pressure (NCPAP) plus intubation, surfactant, and extubation (InSurE) with the option of back-up ventilation for those infants for whom noninvasive ventilatory support failed resulted in a significant increase in survival in extremely low birth weight (ELBW) infants. The authors sought to determine the outcome of ELBW infants treated with NCPAP and InSurE in a neonatal high care ward with limited back-up ventilation.

METHODS

Three hundred eighteen inborn infants with birth weight 500-1000 g and gestational age ≥25 weeks who were admitted to the neonatal high care ward were included in this observational study. InSurE was administered to infants with respiratory distress syndrome on NCPAP who had severe in-drawing and recession, apneic spells, or an Fio(2) >0.4 within 1 hour of birth.

RESULTS

Two hundred twelve (68.6%) infants could be treated with NCPAP only and 97 (31.4%) required InSurE. Seventeen infants were admitted to the NICU; 90%, 87%, and 74.8% of the infants survived until day 3, 7, and discharge, respectively. Only 2 infants developed a pneumothorax and 2 had chronic lung disease. Seventy-nine percent of the infants of ≥750 g or >26 weeks' gestation survived to discharge compared with 56% and 60% of the infants of <750 g or ≤26 weeks' gestation, respectively. Maternal antenatal steroid administration contributed significantly to the survival of the infants (P = 0.0017, odds ratio 2.7, 95% confidence interval 1.44-5.07).

CONCLUSIONS

The use of NCPAP and InSurE in a neonatal high care ward with limited resources can improve the survival of ELBW infants. Maternal antenatal steroid administration contributed significantly to survival.

Antenatal antecedents of cognitive impairment at 24 months in extremely low gestational age newborns

BACKGROUND AND OBJECTIVES

Extremely low gestational age neonates are more likely than term infants to develop cognitive impairment. Few studies have addressed antenatal risk factors of this condition. We identified antenatal antecedents of cognitive impairment determined by the Mental Development Index (MDI) portion of the Bayley Scales of Infant Development, Second Edition (BSID-II), at 24 months corrected age.

METHODS

We studied a multicenter cohort of 921 infants born before 28 weeks of gestation during 2002 to 2004 and assessed their placentas for histologic characteristics and microorganisms. The mother was interviewed and her medical record was reviewed. At 24 months adjusted age, children were assessed with BSID-II. Multinomial logistic models were used to estimate odds ratios.

RESULTS

A total of 103 infants (11%) had an MDI <55, and 99 infants (11%) had an MDI between 55 and 69. No associations were identified between organisms recovered from the placenta and developmental delay. Factors most strongly associated with MDI <55 were thrombosis of fetal vessels (OR 3.1; 95% confidence interval [CI] 1.2, 7.7), maternal BMI >30 (OR 2.0; 95% CI 1.1, 3.5), maternal education ≤12 years (OR 3.4; 95% CI 1.9, 6.2), nonwhite race (OR 2.2; 95% CI 1.3, 3.8), birth weight z score < -2 (OR 2.8; 95% CI 1.1, 6.9), and male gender (OR 2.7; 95% CI 1.6, 4.5).

CONCLUSIONS

Antenatal factors, including thrombosis of fetal vessels in the placenta, severe fetal growth restriction, and maternal obesity, convey information about the risk of cognitive impairment among extremely premature newborns.

Excess soluble vascular endothelial growth factor receptor-1 in amniotic fluid impairs lung growth in rats: linking preeclampsia with bronchopulmonary dysplasia

Epidemiological studies have shown that maternal preeclampsia (PE) increases the risk of bronchopulmonary dysplasia (BPD), but the underlying mechanism is unknown. Soluble vascular endothelial growth factor receptor-1 (soluble VEGFR1, known as soluble fms-like tyrosine kinase 1, or sFlt-1), an endogenous antagonist of vascular endothelial growth factor (VEGF), is markedly elevated in amniotic fluid and maternal blood in PE. Therefore, we hypothesized that antenatal exposure to excess sFlt-1 disrupts lung development through impaired VEGF signaling in utero, providing a mechanistic link between PE and BPD. To determine whether increased sFlt-1 in amniotic fluid is sufficient to cause sustained abnormalities of lung structure during infancy, sFlt-1 or saline was injected into amniotic sacs of pregnant Sprague-Dawley rats at 20 days of gestation (term, 22 days). After birth, pups were observed through 14 days of age for study. We found that intra-amniotic sFlt-1 treatment decreased alveolar number, reduced pulmonary vessel density, and caused right and left ventricular hypertrophy in 14-day-old rats. In addition, intra-amniotic sFlt-1 treatment suppressed activation of lung VEGF receptor-2 and increased apoptosis in endothelial and mesenchymal cells in the newborn lung. We conclude that exposure to excess sFlt-1 in amniotic fluid during late gestation causes sustained reductions in alveolarization and pulmonary vascular growth during infancy, accompanied by biventricular hypertrophy suggesting pulmonary and systemic hypertension. We speculate that impaired VEGF signaling in utero due to exposure of high amniotic fluid levels of sFlt-1 in PE disrupts lung growth and contributes to the increased risk of BPD in infants born to mothers with PE.

An interdisciplinary bronchopulmonary dysplasia program is associated with improved neurodevelopmental outcomes and fewer rehospitalizations

OBJECTIVE

Bronchopulmonary dysplasia (BPD) is a pulmonary disease associated with poor neurodevelopmental and medical outcomes. Patients with BPD are medically fragile, at high risk for complications and require interdisciplinary care. We tested the hypothesis that a chronic care approach for BPD would improve neurodevelopmental outcomes relative to the National Institute of Child and Human Development Neonatal Research Network (NICHD NRN) and reduce medical complications.

STUDY DESIGN

Infants were followed as inpatients and outpatients. Bayley developmental exams were carried out at 18-24 months of age and compared with the NICHD NRN report. Finally, rates of readmission (a proxy for medical complications) were compared before and after implementation of the Comprehensive Center for BPD (CCBPD).

RESULT

Developmental scores obtained in 2007 and 2008 show that 12 and 10% of patients with moderate BPD (n=61) had Bayley Scores <70 for mental and motor indices respectively, whereas corresponding national rates were 35 and 26%. For patients with severe BPD (n=46), 15 and 11% of patients within the CCBPD vs 50 and 42% of national patients scored <70 for mental and motor indices, respectively. Finally, readmission rates dropped from 29% in the year before the implementation of the CCPD (n=269) to 5% thereafter (n=866, P<0.0001).

CONCLUSION

The encouraging neurodevelopmental outcomes and readmission rates associated with a chronic care approach to BPD suggest these infants may be best served by a comprehensive interdisciplinary approach to care that focuses on neurodevelopment throughout the hospital stay.

Aberrant signaling pathways of the lung mesenchyme and their contributions to the pathogenesis of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease in infants born extremely preterm, typically before 28 weeks' gestation, characterized by a prolonged need for supplemental oxygen or positive pressure ventilation beyond 36 weeks postmenstrual age. The limited number of autopsy samples available from infants with BPD in the postsurfactant era has revealed a reduced capacity for gas exchange resulting from simplification of the distal lung structure with fewer, larger alveoli because of a failure of normal lung alveolar septation and pulmonary microvascular development. The mechanisms responsible for alveolar simplification in BPD have not been fully elucidated, but mounting evidence suggests that aberrations in the cross-talk between growth factors of the lung mesenchyme and distal airspace epithelium have a key role. Animal models that recapitulate the human condition have expanded our knowledge of the pathology of BPD and have identified candidate matrix components and growth factors in the developing lung that are disrupted by conditions that predispose infants to BPD and interfere with normal vascular and alveolar morphogenesis. This review focuses on the deviations from normal lung development that define the pathophysiology of BPD and summarizes the various candidate mesenchyme-associated proteins and growth factors that have been identified as being disrupted in animal models of BPD. Finally, future areas of research to identify novel targets affected in arrested lung development and recovery are discussed.

Postnatal corticosteroids for prevention and treatment of chronic lung disease in the preterm newborn

Despite significant progress in the treatment of preterm neonates, bronchopulmonary dysplasia (BPD) continues to be a major cause of neonatal morbidity. Affected infants suffered from long-term pulmonary and nonpulmonary sequel. The pulmonary sequels include reactive airway disease and asthma during childhood and adolescence. Nonpulmonary sequels include poor coordination and muscle tone, difficulty in walking, vision and hearing problems, delayed cognitive development, and poor academic achievement. As inflammation seems to be a primary mediator of injury in pathogenesis of BPD, role of steroids as antiinflammatory agent has been extensively studied and proven to be efficacious in management. However, evidence is insufficient to make a recommendation regarding other glucocorticoid doses and preparations. Numerous studies have been performed to investigate the effects of steroid. The purpose of this paper is to evaluate these studies in order to elucidate the beneficial and harmful effects of steroid on the prevention and treatment of BPD.

Elastase inhibitory activity of airway α1-antitrypsin is protected by treatment with a catalytic antioxidant in a baboon model of severe bronchopulmonary dysplasia

Recent studies in animal models of bronchopulmonary dysplasia (BPD) suggest that antioxidant treatments may be beneficial for the disease. However, the mechanisms by which these drugs improve the course of BPD are not completely known. Alpha1-antitrypsin (α1-AT) is one of the major serine protease inhibitors in human plasma that has antielastase and antiapoptotic activities. Both activities of α1-AT are dependent on its reactive site loop (RSL), which is highly susceptible to oxidative inactivation. In this study, we investigated the elastase inhibitory activity of α1-AT in two different baboon models of BPD, the "new BPD" and the "severe BPD" models, and determined the effect of treatment with a catalytic antioxidant, Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP), on the elastase inhibitory activity of α1-AT in the severe BPD model. Our results demonstrate the presence of sufficient elastase inhibitory activity of the airway α1-AT in the new but not in the severe BPD model. Treatment of severe BPD group baboons with the catalytic antioxidant MnTE-2-PyP resulted in augmentation of the elastase inhibitory activity of α1-AT. These findings suggest that prevention of the oxidative inactivation of α1-AT may be one of the mechanisms by which antioxidant therapy improves the pulmonary outcomes in animal models of severe BPD.

Targeting inflammation to prevent bronchopulmonary dysplasia: can new insights be translated into therapies?

Bronchopulmonary dysplasia (BPD) frequently complicates preterm birth and leads to significant long-term morbidity. Unfortunately, few therapies are known to effectively prevent or treat BPD. Ongoing research has been focusing on potential therapies to limit inflammation in the preterm lung. In this review we highlight recent bench and clinical research aimed at understanding the role of inflammation in the pathogenesis of BPD. We also critically assess currently used therapies and promising developments in the field.

Preverbal skills as mediators for language outcome in preterm and full term children

Language delay is a well documented problem that occurs on a higher rate in preterm children compared to full term children. Preverbal social skills, such as the ability to share attention to an object with another person (i.e., triadic interaction), are suggested to reflect part of the processes through which children learn language. This longitudinal study examined preverbal and verbal skills in 25 preterm and 35 full term children in order to investigate if birth status affects language development through the proposed mediating processes of preverbal dyadic and triadic skills. Dyadic initiatives during the still-face episode were assessed at 6 months. Triadic responsiveness (gaze following) was examined at 9 and 14 months. Triadic initiatives (joint attention and behavioral request) were also assessed at 14 months. At 30 months, receptive and expressive language was examined. The data showed group differences in 6-month dyadic initiatives, 9-month triadic responsiveness, 14-month triadic behavioral request initiatives and 30-month receptive and expressive language skills at the expense of the preterm children, confirming their risk for a less favorable preverbal and verbal development. Multiple mediation analyses confirmed the hypothesis that birth status affects language development partially through preverbal skills, which is important for clinical practice.

Neurodevelopmental outcome over time of preterm born children ≤750 g at birth

BACKGROUND

Extremely low birth weight (ELBW) infants are at risk of cognitive impairment and follow-up is therefore of major importance. The age at which their neurodevelopmental outcome (NDO) can reliably be predicted differs in the literature.

AIMS

To describe NDO at 2, 3.5 and 5.5 years in an ELBW cohort. To examine the value of NDO at 2 years corrected age (CA) for prediction of NDO at 3.5 and 5.5 years.

STUDY DESIGN

A retrospective cross-sectional and longitudinal cohort study.

SUBJECTS

101 children with a BW≤750 g, born between 1996 and 2005, who survived NICU admission and were included in a follow-up program.

OUTCOME MEASURES

NDO, measured with different tests for general development and intelligence, depending on age of assessment and classified as normal (Z-score≥-1), mildly delayed (-2≤Z-score<-1) or severely delayed (Z-score<-2).

RESULTS

At 2, 3.5 and 5.5 years 74.3, 82.2 and 76.2% had a normal NDO. A normal NDO at 2 years CA predicted a normal NDO at 3.5 and 5.5 years in 92% and 84% respectively. Of the children with a mildly or severely delayed NDO at 2 years CA the majority showed an improved NDO at 3.5 (69.2%) and 5.5 years (65.4%) respectively.

CONCLUSIONS

The majority of the children with a BW≤750 g had a normal NDO at all ages. A normal NDO at 2 years CA is a good predictor for normal outcome at 3.5 and 5.5 years, whereas a delayed NDO at 2 years CA is subject to change with the majority of the children showing a better NDO at 3.5 and 5.5 years.

Neuromotor outcomes in infants with bronchopulmonary dysplasia

We examine the neuromotor outcomes of preterm infants with bronchopulmonary dysplasia. Two hundred and nineteen infants (gestational age, ≤ 32 weeks; birth weight, ≤ 1500 g) were studied. Neuromotor development was assessed using the Hammersmith Infant Neurological Examination. All potential risk factors associated with neuromotor scores (P < 0.015) were included in the generalized linear model (multiple linear regression) to determine if bronchopulmonary dysplasia had an independent relationship with neuromotor scores. Infants with severe bronchopulmonary dysplasia had lower global scores at ages 6 and 12 months. After adjustment for confounding factors, scores of infants with severe bronchopulmonary dysplasia were reduced by 13.2 units, whereas scores for those with periventricular leukomalacia were reduced by 11.1 units, at age 6 months. At age 12 months, scores for those with periventricular leukomalacia were reduced by 11.9 units. Duration of hospital stay reduced scores by 0.1 for each additional day increase in hospital. Bronchopulmonary dysplasia constitutes a major cause of poor neuromotor outcomes at age 6 months, but improvements in motor outcomes occur over time.

The management of evolving bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is associated with increased mortality and significant long-term cardiorespiratory and neurodevelopmental sequelae. Treatment of evolving BPD in the neonatal intensive care unit (NICU) is challenging due to the complex interplay of contributing risk factors which include preterm birth per se, supplemental oxygen, positive pressure ventilation, patent ductus arterious, and pre- and postnatal infection. Management of evolving BPD requires a multimodal approach including adequate nutrition, careful fluid management, effective and safe pharmacotherapy, and respiratory support aiming at minimal lung injury. Among pharmacological interventions, caffeine has the best risk-benefit profile. Systemic postnatal corticosteroids should be reserved to ventilated infants at highest risk of BPD who cannot be weaned from the ventilator. Several ongoing randomised trials are evaluating optimal oxygen saturation targets in preterm infants. The most beneficial respiratory support strategy to minimise lung injury remains unclear and requires further investigation.

Conductive hearing loss in children with bronchopulmonary dysplasia: a longitudinal follow-up study in children aged between 6 and 24 months

AIMS

To determine the occurrence of isolated and recurrent episodes of conductive hearing loss (CHL) during the first two years of life in very low birth weight (VLBW) infants with and without bronchopulmonary dysplasia (BPD). STUDY DESIGN, SUBJECTS AND OUTCOME MEASURES: In a longitudinal clinical study, 187 children were evaluated at 6, 9, 12, 15 18 and 24 months of age by visual reinforcement audiometry, tympanometry and auditory brain response system.

RESULTS

Of the children with BPD, 54.5% presented with episodes of CHL, as opposed to 34.7% of the children without BPD. This difference was found to be statistically significant. The recurrent or persistent episodes were more frequent among children with BPD (25.7%) than among those without BPD (8.3%). The independent variables that contributed to this finding were small for gestational age and a 5 min Apgar score.

CONCLUSIONS

Recurrent CHL episodes are more frequent among VLBW infants with BPD than among VLBW infants without BPD.