The adverse neuro-developmental effects of postnatal steroids in the preterm infant: a systematic review of RCTs

Evidence for adverse effect of perinatal glucocorticoid use on the developing brain

The use of glucocorticoids (GCs) in the perinatal period is suspected of being associated with adverse effects on long-term neurodevelopmental outcomes for preterm infants. Repeated administration of antenatal GCs to mothers at risk of preterm birth may adversely affect fetal growth and head circumference. Fetal exposure to excess GCs during critical periods of brain development may profoundly modify the limbic system (primarily the hippocampus), resulting in long-term effects on cognition, behavior, memory, co-ordination of the autonomic nervous system, and regulation of the endocrine system later in adult life. Postnatal GC treatment for chronic lung disease in premature infants, particularly involving the use of dexamethasone, has been shown to induce neurodevelopmental impairment and increases the risk of cerebral palsy. In contrast to studies involving postnatal dexamethasone, long-term follow-up studies for hydrocortisone therapy have not revealed adverse effects on neurodevelopmental outcomes. In experimental studies on animals, GCs has been shown to impair neurogenesis, and induce neuronal apoptosis in the immature brains of newborn animals. A recent study has demonstrated that dexamethasone-induced hypomyelination may result from the apoptotic degeneration of oligodendrocyte progenitors in the immature brain. Thus, based on clinical and experimental studies, there is enough evidence to advice caution regarding the use of GCs in the perinatal period; and moreover, the potential long-term effects of GCs on brain development need to be determined.

Early postnatal additional high-dose oral vitamin A supplementation versus placebo for 28 days for preventing bronchopulmonary dysplasia or death in extremely low birth weight infants

BACKGROUND

Prematurity and the associated risk for bronchopulmonary dysplasia (BPD) remain a significant threat to extremely low birth weight (ELBW) infants. Vitamin A has been considered a therapeutic alternative in reducing the rate of BPD and mortality.

OBJECTIVES

To investigate whether early postnatal, additional high-dose oral vitamin A supplementation for 28 days is more efficient in reducing BPD or death in ELBW infants than placebo treatment.

METHODS

This is a multicenter, double-blind RCT comparing postnatal high-dose oral vitamin A supplementation (5,000 IU vitamin A/kg/day vs. placebo) for 28 days in ELBW neonates requiring mechanical ventilation, noninvasive ventilatory support or supplemental oxygen at 24 h of age. The primary end point is the proportion of children who died before 36 weeks' gestational age or developed moderate or severe BPD. BPD is defined as the need for supplemental oxygen to maintain SaO2 of ≥92% at rest at 36 weeks' postmenstrual age (PMA). Clinical secondary end points include the following: BPD (including mild form), intraventricular hemorrhage, periventricular leukomalacia, retinopathy of prematurity, necrotizing enterocolitis, total number of days of mechanical ventilation and oxygen supplementation, and safety and tolerability of high-dose vitamin A supplementation.

RESULTS AND CONCLUSIONS

The results of the NeoVitaA trial will provide robust data with regard to the efficacy of high-dose oral vitamin A supplementation in reducing the incidence of BPD or death at 36 weeks' PMA in ELBW infants.

Context modulates outcome of perinatal glucocorticoid action in the brain

Prematurely born infants may be at risk, because of inadequate maturation of tissues. If there are signs of preterm birth, it has become common practice therefore to treat either antenatally the mother or postnatally the infant with glucocorticoids to accelerate tissue development, particularly of the lung. However, this life-saving early glucocorticoid treatment was found to increase the risk of adverse outcome in later life. In one animal study, the authors reported a 25% shorter lifespan of rats treated as newborns with the synthetic glucocorticoid dexamethasone, but so far this finding has not been replicated. After a brief clinical introduction, we discuss studies in rodents designed to examine how perinatal glucocorticoid action affects the developing brain. It appears that the perinatal action of the glucocorticoid depends on the context and the timing as well as the type of administered steroid. The type of steroid is important because the endogenous glucocorticoids cortisol and corticosterone bind to two distinct receptor populations, i.e., mineralocorticoid and glucocorticoid receptors (GR), while synthetic glucocorticoids predominantly bind to the GR. In addition, if given antenatally hydrocortisone is inactivated in the placenta by 11β-HSD type 2, and dexamethasone is not. With respect to timing, the outcome of glucocorticoid effects is different in early vs. late phases of brain development. The context refers to the environmental input that can affect the susceptibility to glucocorticoid action in the newborn rodent brain; early handling of pups and maternal care obliterate effects of post-natal dexamethasone treatment. Context also refers to coping with environmental conditions in later life, for which the individual may have been programed epigenetically by early-life experience. This knowledge of determinants affecting the outcome of perinatal glucocorticoid exposure may have clinical implications for the treatment of prematurely born infants.

Statins prevent adverse effects of postnatal glucocorticoid therapy on the developing brain in rats

BACKGROUND

Postnatal glucocorticoid therapy in the treatment of chronic lung disease benefits lung function, however it adversely affects brain development. We hypothesized that combined postnatal glucocorticoid and statin therapy diminishes adverse effects of glucocorticoids on the developing brain.

METHODS

On postnatal days (P) 1-3, one male pup per litter received i.p. injections of saline control (C), n = 13) or dexamethasone (0.5, 0.3, 0.1 µg/g; D, n = 13), ± pravastatin (10 mg/kg i.p.; CP, n = 12; DP, n = 15). Statins or saline continued from P4-6. At P21, brains were perfusion fixed for histological and stereological analyses.

RESULTS

Relative to controls, dexamethasone reduced total (837 ± 23 vs. 723 ± 37), cortical (378 ± 12 vs. 329 ± 15), and deep gray matter (329 ± 12 vs. 284 ± 15) volume (mm(3)), cortical neuronal number (23 ± 1 vs. 19 ± 1 × 10(6)), and hippocampal neuronal soma volume (CA1: 1,206 ± 32 vs. 999 ± 32; dentate gyrus: 679 ± 28 vs. 542 ± 24 µm(3); all P < 0.05). Dexamethasone increased the glial fibrillary acidic protein-positive astrocyte density in the white matter (96 ± 2 vs. 110 ± 4/0.1 mm(2)); P < 0.05. These effects no longer occurred in brains from pups treated with combined dexamethasone and pravastatin. Pravastatin alone had no effect on these variables.

CONCLUSION

Concomitant dexamethasone with statins in premature infants may be safer for the developing brain than dexamethasone alone in the treatment of chronic lung disease.

Circulatory insulin-like growth factor-I and brain volumes in relation to neurodevelopmental outcome in very preterm infants

BACKGROUND

To evaluate the relationships between postnatal change in circulatory insulin-like growth factor-I (IGF-I) concentrations, brain volumes, and developmental outcome at 2 y of age in very preterm infants.

METHODS

IGF-I was measured weekly, and nutritional intake was calculated daily from birth until a postmenstrual age (PMA) of 35 wk. Individual β coefficients for IGF-I, IGF-I(B), representing the rate of increase in IGF-I from birth until a PMA of 35 wk were calculated. Brain magnetic resonance imaging was performed at term age, with segmentation into total brain, cerebellar, gray matter, and unmyelinated white matter volume (UWMV). Developmental outcome was evaluated using Bayley Scales of Infant Development-II.

RESULTS

Forty-nine infants, with mean gestational age (GA) of 26.0 wk, were evaluated at mean 24.6 mo corrected age. Higher IGF-I(B), UWMV, and cerebellar volume were associated with a decreased risk for a Mental Developmental Index (MDI) < 85 (odds ratio (95% confidence interval): 0.6 (0.4-0.9), 0.96 (0.94-0.99), and 0.78 (0.6-0.96), respectively). In multivariate analysis, higher IGF-I(B) and higher UWMV combined with female gender constituted the two models with the highest predictive value for MDI > 85.

CONCLUSION

A higher rate of increase in circulating IGF-I is associated with a decreased risk for subnormal MDI at 2 y of corrected age. This relationship is in part dependent on brain volume at term age.

Role of the NMDA receptor in cognitive deficits, anxiety and depressive-like behavior in juvenile and adult mice after neonatal dexamethasone exposure

Postnatal dexamethasone (DEX) therapy has been used to treat or prevent chronic lung disease after premature births. However, there are many reports of long-term negative neurodevelopmental sequelae following this treatment. In contrast, hydrocortisone (HYD), which has fewer neurodevelopment adverse effects, is used as an alternative for DEX. In this study, we report that neonatal DEX exposure (days 1-3) caused alterations of amino acids affecting N-methyl-d-aspartate (NMDA) receptor neurotransmission in mouse brains. Neonatal DEX, but not HYD, exposure (days 1-3) significantly decreased the GluN2B subunit of NMDA receptor in the hippocampus at juvenile and adult stages. Mice treated with DEX showed cognitive deficits, as well as anxiety and depressive-like behavior at juvenile and adult stages. In contrast, mice treated with HYD (days 1-3) showed no behavioral abnormalities at these stages. In the DEX suppression test, plasma levels of corticosterone in mice exposed neonatally to DEX and HYD were significantly higher at juvenile, but not adult stages. Pretreatment with Ro 63-1908, an antagonist at GluN2B subunit, 30min before each injection of DEX, prevented cognitive deficits, as well as anxiety and depressive-like behavior in juvenile and adult mice. Interestingly, subsequent repeated (days 29-33) administration of Ro 63-1908 or L701324, an antagonist of the glycine modulatory site on the NMDA receptor, significantly suppressed behavioral abnormalities in juvenile and adult mice after neonatal DEX exposure. These results indicate that neonatal DEX, but not HYD, exposure produced behavioral abnormalities in juvenile and adult mice by altering glutamatergic neurotransmission via the NMDA receptor. The NMDA receptor antagonists may prevent or treat these DEX-induced neonatal behavioral abnormalities in later life.

Parental presence and holding in the neonatal intensive care unit and associations with early neurobehavior

OBJECTIVE

To investigate the effects of parental presence and infant holding in the neonatal intensive care unit (NICU) on neurobehavior at term equivalent.

STUDY DESIGN

Prospective cohort enrolled 81 infants born 30 weeks gestation. Nurses tracked parent visitation, holding and skin-to-skin care throughout the NICU hospitalization. At term, the NICU Network Neurobehavioral Scale was administered. Associations between visitation, holding and early neurobehavior were determined using linear and logistic regression.

RESULT

The mean hours per week of parent visitation was 21.33±20.88 (median=13.90; interquartile range 10.10 to 23.60). Infants were held an average of 2.29±1.47 days per week (median=2.00; interquartile range 1.20 to 3.10). Over the hospital stay, visitation hours decreased (P=0.01), while holding frequencies increased (P<0.001). More visitation was associated with better quality of movement (P=0.02), less arousal (P=0.01), less excitability (P=0.03), more lethargy (P=0.01) and more hypotonia (P<0.01). More holding was associated with improved quality of movement (P<0.01), less stress (P<0.01), less arousal (P=0.04) and less excitability (P<0.01).

CONCLUSION

Infants of caregivers who were visited and held more often in the NICU had differences in early neurobehavior by term equivalent, which supports the need for and importance of early parenting in the NICU.

Evolving neonatal steroid prescription habits and patient outcomes

AIM

Indications for post-natal steroids among preterm infants are evolving. The objective of this study was to compare steroid use in 2 cohorts 5 years apart and to document the short- and long-term outcomes of our most recent cohort.

METHODS

Retrospective chart review of infants born under 28 weeks of gestational age for two cohorts (January 2002-August 2003 and July 2008-March 2010).

RESULTS

Two hundred and fourteen infants were included. More infants received steroids in the later cohort (20% vs 35%, p = 0.021) but survival rates did not improve. There was a shift towards hydrocortisone use (<7% vs 76%) and pulmonary indications (36% vs 61% of courses; p = 0.021). Patients died later (8 days vs 30 days; p = 0.02), with a strong correlation between time of death and total dose of steroids (r = 0.91; p = 0.01). Neurodevelopmental outcomes for patients who received steroids for pulmonary indications were inferior to those for the rest of the cohort (severe adverse outcome 26% vs 4.8%, p = 0.03).

CONCLUSION

The improvement in short-term respiratory status of ill preterm patients was offset by a disturbing increase in age at death and no improvement in survival rates.

Early life intervention with glucocorticoids has negative effects on motor development and neuropsychological function in 14-17 year-old adolescents

OBJECTIVE

To reduce the risk of bronchopulmonary dysplasia, preterm infants receive neonatal treatment with glucocorticoids, mostly dexamethasone (DEX). Compared to current protocols, treatment regimens of the late 1980s - early 1990s prescribed high doses of DEX for an extensive period up to 6 weeks. Worldwide at least one million children have been treated with this dose regimen. Previous studies have shown adverse effects of neonatal treatment with the glucocorticoid dexamethasone (DEX) on outcome in children aged 7-10 years. On the other hand, treatment with another glucocorticoid, hydrocortisone (HC), was not related to adverse effects in childhood. In the current study we determined the consequences of early life intervention with DEX or HC in adolescents (age 14-17 years). Besides motor function and intellectual capacities, we also examined fundamental neuropsychological functions which have so far received little attention.

METHODS

In an observational cohort study we compared 14-17 year-old adolescents who received DEX (.5 mg/kg/day tapering off to .1 mg/kg/day over 21 days, n=63), or HC (5 mg/kg/day tapering off to 1 mg/kg/day over 22 days, n=67), or did not receive neonatal glucocorticoids (untreated, n=71) after premature birth (gestational age<32 weeks). Because gestational age was shorter and duration of ventilation was longer in the DEX-treated group, all analyses were corrected for these potential confounders. Motor function, IQ, and neuropsychological functions were assessed.

RESULTS

DEX-treated group participants scored lower on gross motor skill tasks than their HC-treated and untreated counterparts. A higher proportion of DEX-treated girls needed special education compared to the other groups. DEX-treated adolescents performed poorer on neuropsychological tasks measuring alertness, visuomotor coordination, and emotion recognition. The HC-treated group did not differ from the untreated group.

CONCLUSIONS

Even after 14-17 years, neonatal treatment with .5 mg/kg/day DEX was associated with adverse effects on motor function, school level, and neuropsychological functions, whereas treatment with the clinically equally effective dose of 5 mg/kg/day HC was not. Potential physiological mechanisms underlying the differences in dexamethasone and hydrocortisone effects are discussed. Based on the current findings, we recommend early identification of neuropsychological deficits after DEX treatment in order to specify extra educational needs.

Dexamethasone administration to the neonatal rat results in neurological dysfunction at the juvenile stage even at low doses

Dexamethasone (DEX), a synthetic glucocorticoid, has been widely used to prevent the development of a variety of poor health conditions in premature infants including chronic lung disease, inflammation, circulatory failure, and shock. Although there are some reports of neurologic complications related to DEX exposure, its full effects on the premature brain have not been examined in detail. To investigate the effects of DEX on neural development, we first administered low doses (0.2 mg/kg bodyweight or less) of the glucocorticoid to neonatal rats on a daily basis during the first postnatal week and examined subsequent behavioral alterations at the juvenile stage. DEX-treated rats exhibited not only a significant reduction in both somatic and brain weights but also learning disabilities as revealed in the shuttle avoidance test. The hippocampi of DEX-treated rats displayed a high apoptotic and a low mitotic cell density compared to control rats on day 7 after birth. In a subsequent experiment, neural stem/progenitor cells were cultured in the presence of DEX for 6 days. The glucocorticoid inhibited cell growth without an increase in cell death. These results suggest that administration of DEX to premature infants induces neurological dysfunction via inhibition of the proliferation of neural stem/progenitor cells.

Neonatal dexamethasone treatment exacerbates hypoxic-ischemic brain injury

Background

The synthetic glucocorticoid dexamethasone (DEX) is commonly used to prevent chronic lung disease in prematurely born infants. Treatment regimens usually consist of high doses of DEX for several weeks, notably during a critical period of brain development. Therefore, there is some concern about adverse effects of this clinical practice on fetal brain development. In this study, using a clinically relevant rat model, we examined the impact of neonatal DEX treatment on subsequent brain injury due to an episode of cerebral hypoxia-ischemia (HI).

Results

We found that a 3-day tapering course (0.5, 0.3 and 0.1 mg/kg) of DEX treatment in rat pups on postnatal days 1–3 (P1-3) exacerbated HI-induced brain injury on P7 by a glucocorticoid receptor-mediated mechanism. The aggravating effect of neonatal DEX treatment on HI-induced brain injury was correlated with decreased glutamate transporter-1 (GLT-1)-mediated glutamate reuptake. The expression levels of mRNA and protein of GLT-1 were significantly reduced by neonatal DEX treatment. We also found that the administration of β-lactam antibiotic ceftriaxone increased GLT-1 protein expression and significantly reduced HI-induced brain injury in neonatal DEX-treated rats.

Conclusions

These results suggest that early DEX exposure may lead the neonatal brain to be more vulnerable to subsequent HI injury, which can be ameliorated by administrating ceftriaxone.

A healthy nation: strengthening child health research in the UK

Despite a general acknowledgment that research in children is necessary and ethical, the evidence base for child-specific treatments is still sparse. We investigated children's biomedical and health services research in the UK in relation to training, infrastructure and activity, research evidence, and visibility. We show that excellent opportunities for career researchers exist through a competitive, national integrated academic training programme, but that the number of academic paediatricians has decreased by 18% between 2000 and 2011, falling from 11·3% to 5·9% of the consultant workforce. The potential for rapid delivery of studies in children through the National Health Service (NHS) is not being realised: clinical trainees are poorly equipped with core research skills; most newly appointed consultant paediatricians have little or no research experience; less than 5% of contracted consultant time supports research; less than 2·5% of the 2 million children seen in the NHS every year are recruited to studies; and ten of the 20 UK children's hospitals do not have a clinical research facility. Support through National Institute for Health Research networks is good for studies into drugs, but inconsistent for non-drug research; less than 5% of registered studies involve children and only one children's biomedical research centre has been allocated funding from 2012. Of the UK annual public and charitable biomedical research expenditure of roughly £2·2 billion, about 5% is directed at child health research. The scant evidence base is impeding the development of clinical guidance and policy-less than 20% of the outputs of the National Institute for Health and Clinical Excellence are applicable to children. Paediatric representation on major research boards is weak. Parent and young people's advocacy is fragmented, and their views are insufficiently heeded by regulatory bodies. The strong UK Government commitment to biomedical research has not been translated fully to research for children. The power of research in children to turn the tide of the growing burden of non-communicable, chronic, adult diseases that have their origins in early life, to benefit the health of an ageing population and future generations, and to reduce health-care costs is inadequately recognised. On the basis of our findings, we make several recommendations to improve early-years research, including the formation of multidisciplinary, cross-institutional groups of clinical and non-clinical child health researchers and their access to diagnostic and laboratory facilities suitable for children; a unified Children's Research Network for drug studies and non-drug studies; regulatory assessment of research that is proportionate and based on consistent national criteria; an expansion of research posts; support for parents' and young people's advocacy; collaboration between children's research charities; improved research training for paediatric trainees; and closer integration of child health research with core NHS activities.

A psychoneuroimmunologic examination of cumulative perinatal steroid exposures and preterm infant behavioral follow-up

PURPOSE

This study's aim was to explore relationships between preterm infant behavioral outcomes and maternal/infant glucocorticoid (dexamethasone [DEX]) treatments using a psychoneuroimmunologic approach. Research questions were (a) do relationships exist between infant cumulative perinatal steroid (PNS) exposure and child behavioral problems? and (b) do maternal/infant characteristics (e.g., immune markers and biophysiologic stressors) influence these relationships?

METHODS

The convenience sample comprised 45 mother-child dyads in which the children (mean age 8 years ± 2.3) had been born at a mean postconceptional age of 28 weeks (± 4.2). We used the Child Behavior Checklist (CBCL) to assess behavior, the Clinical Risk Index for Babies (CRIB) to score stress at birth, and retrospective record review to identify additional perinatal factors (PNS dosage, sepsis, and maternal and infant complete blood counts near delivery).

RESULTS

Children were dichotomized into high (> 0.2 mg/kg; n = 20) versus low-no (≤0.2 mg/kg; n = 25) PNS exposure groups. Significant relationships existed between CBCL Total Problems score and sepsis, PNS exposure, timing of initial PNS, and infant length percentile at discharge. Competence problems were significantly associated with PNS, neonatal intensive care unit (NICU) infant length percentile, CRIB score, sepsis, retinopathy of prematurity, hearing deficit, and immunity markers (i.e., maternal lymphocyte percentage and infant band/seg ratio). Children in the higher PNS group exhibited more behavioral problems (e.g., withdrawn, attention, conduct, social, and rule breaking problems), but there were no significant differences. The findings are reassuring regarding long-term effects of this PNS dose on preterm infant behavioral outcomes.

Outcome at two years of age in a Swiss national cohort of extremely preterm infants born between 2000 and 2008

BACKGROUND

While survival rates of extremely preterm infants have improved over the last decades, the incidence of neurodevelopmental disability (ND) in survivors remains high. Representative current data on the severity of disability and of risk factors associated with poor outcome in this growing population are necessary for clinical guidance and parent counselling.

METHODS

Prospective longitudinal multicentre cohort study of preterm infants born in Switzerland between 24(0/7) and 27(6/7) weeks gestational age during 2000-2008. Mortality, adverse outcome (death or severe ND) at two years, and predictors for poor outcome were analysed using multilevel multivariate logistic regression. Neurodevelopment was assessed using Bayley Scales of Infant Development II. Cerebral palsy was graded after the Gross Motor Function Classification System.

RESULTS

Of 1266 live born infants, 422 (33%) died. Follow-up information was available for 684 (81%) survivors: 440 (64%) showed favourable outcome, 166 (24%) moderate ND, and 78 (11%) severe ND. At birth, lower gestational age, intrauterine growth restriction and absence of antenatal corticosteroids were associated with mortality and adverse outcome (p < 0.001). At 36(0/7) weeks postmenstrual age, bronchopulmonary dysplasia, major brain injury and retinopathy of prematurity were the main predictors for adverse outcome (p < 0.05). Survival without moderate or severe ND increased from 27% to 39% during the observation period (p = 0.02).

CONCLUSIONS

In this recent Swiss national cohort study of extremely preterm infants, neonatal mortality was determined by gestational age, birth weight, and antenatal corticosteroids while neurodevelopmental outcome was determined by the major neonatal morbidities. We observed an increase of survival without moderate or severe disability.

Antenatal dexamethasone has no adverse effects on child physical and cognitive development: a long-term cohort follow-up investigation

OBJECTIVE

Antenatal corticosteroids are extensively given in pregnancies with threatened preterm labour as a prophylactic method to reduce some kinds of neonatal diseases. Dexamethasone is one kind of commonly used corticosteroid, but controversies still remain whether it leads to adverse effects on neonatal long-term development or not. The purpose of this study was to investigate the influence of prenatal exposure to one or two dosages of dexamethasone on neonatal physical and cognitive development of children at 1, 3 and 6 years of age.

METHODS

This was a retrospective cohort study. The body length, head circumference and body weight were measured in every infant and child to evaluate physical development. The mental development index (MDI) and a psychomotor development index (PDI) were used to evaluate mental and cognitive development in children of ages 1 year and 3 years while verbal intelligence quotient (VIQ) and performance intelligence quotient (PIQ) scores were used to evaluate mental and cognitive development in children of age of 6 years. There were 1554 infants at 1 year, 1328 children at 3 years and 1297 preschool children at 6 years followed.

RESULTS

There were no significant differences between antenatal dexamethasone exposure groups and antenatal dexamethasone non-exposure groups on physical development index and MDI, PDI, VIQ and PIQ.

CONCLUSIONS

The results of this investigation suggested that one or two dosages of antenatal dexamethasone is safe for the use of inevitable preterm birth.

Early handling modulates outcome of neonatal dexamethasone exposure

Synthetic glucocorticoids such as dexamethasone (DEX) are used to prevent or treat respiratory disorders in prematurely born infants. Besides the short-term benefit on lung development, numerous human and animal studies have reported adverse neurodevelopmental side effects. In contrast, maternal care is known to exert a positive influence on neurodevelopmental outcome in rodents. The aim of the current study was therefore to investigate whether neonatal handling (days 1-21), known to induce maternal care, might serve as an intervention strategy modulating the adverse effects of DEX treatment (days 1-3). For this purpose we have measured the outcome of these early-life manipulations on development as well as adult endocrine and behavioral phenotype of male rats. Maternal care was observed during the first week of life and indeed enhanced in response to handling. Eye opening was accelerated and body weight reduced in DEX-treated animals. In adulthood, we report that handling ameliorated impaired spatial learning observed in DEX treated non-handled animals in the T-maze. Additionally, handling reduced susceptibility to the impact of DEX treatment in the water maze. Although DEX treatment and handling both resulted in enhanced negative feedback of the stress-induced corticosterone response and both reduced startle reactivity, the acquisition of fear was only reduced by handling, without effect of DEX. Interestingly, handling had a beneficial effect on pre-pulse inhibition, which was diminished after DEX treatment. In conclusion, these findings indicate that handling of the neonate enhances maternal care and attenuates specific DEX-induced alterations in the adult behavioral phenotype.

Sex, stress, and mood disorders: at the intersection of adrenal and gonadal hormones

The risk for neuropsychiatric illnesses has a strong sex bias, and for major depressive disorder (MDD), females show a more than 2-fold greater risk compared to males. Such mood disorders are commonly associated with a dysregulation of the hypothalamo-pituitary-adrenal (HPA) axis. Thus, sex differences in the incidence of MDD may be related with the levels of gonadal steroid hormone in adulthood or during early development as well as with the sex differences in HPA axis function. In rodents, organizational and activational effects of gonadal steroid hormones have been described for the regulation of HPA axis function and, if consistent with humans, this may underlie the increased risk of mood disorders in women. Other developmental factors, such as prenatal stress and prenatal overexposure to glucocorticoids can also impact behaviors and neuroendocrine responses to stress in adulthood and these effects are also reported to occur with sex differences. Similarly, in humans, the clinical benefits of antidepressants are associated with the normalization of the dysregulated HPA axis, and genetic polymorphisms have been found in some genes involved in controlling the stress response. This review examines some potential factors contributing to the sex difference in the risk of affective disorders with a focus on adrenal and gonadal hormones as potential modulators. Genetic and environmental factors that contribute to individual risk for affective disorders are also described. Ultimately, future treatment strategies for depression should consider all of these biological elements in their design.

Effects of antenatal glucocorticoid therapy on hippocampal histology of preterm infants

OBJECTIVE

To investigate if antenatal glucocorticoid treatment has an effect on hippocampal histology of the human preterm newborn.

PATIENTS AND METHODS

Included were consecutive neonates with a gestational age between 24 and 32 weeks, who were born between 1991 to 2009, who had died within 4 days after delivery and underwent brain autopsy. Excluded were neonates with congenital malformations and neonates treated postnatally with glucocorticoids. The brains were routinely fixed, samples of the hippocampus were stained with haematoxylin and eosin and sections were examined for presence or absence of large and small neurons in regions of the hippocampus. Additional staining with GFAP, neurofilament and vimentin was performed to evaluate gliosis and myelination. The proliferation marker Ki67 was used to evaluate neuronal proliferation. Staining with acid fuchsin-thionin was performed to evaluate ischemic damage.

RESULTS

The hippocampi of ten neonates who had been treated with antenatal glucocorticoids showed a lower density of large neurons (p = 0.01) and neurons irrespective of size (p = 0.02) as compared to eleven neonates who had not been treated with glucocorticoids. No difference was found in density of small neurons, in myelination, gliosis, proliferation or ischemic damage.

CONCLUSION

We found a significantly lower density of neurons in the hippocampus of neonates after antenatal glucocorticoid treatment. Although the pathophysiological and clinical interpretations of these findings are not clear, they are consistent with those from experiments in mice and rhesus monkeys.

Evidence-based neonatal pharmacotherapy: postnatal corticosteroids

Corticosteroids are used in the neonatal intensive care unit primarily to treat two conditions: bronchopulmonary dysplasia (BPD) and hypotension (cardiovascular insufficiency). Historically, high-dose dexamethasone was used for BPD, but its use was later associated with adverse neurodevelopmental outcomes and decreased substantially. Data from randomized controlled trials regarding efficacy and safety of lower-dose dexamethasone therapy are insufficient to recommend its use. Hydrocortisone may be an alternative to dexamethasone, but again data are insufficient to support use. Hydrocortisone therapy is increasingly used to treat hypotension in critically ill newborns; however, the outcomes of this therapy must be evaluated in randomized trials.

Neuropsychological and behavioral effects of postnatal dexamethasone in extremely low birth weight preterm children at early school age

OBJECTIVE

To study postnatal dexamethasone treatment effects on cognitive, neuropsychological and behavioral functioning at early school age in preterm children.

STUDY DESIGN

We recruited 222 children born between 1998 and 2003: 114 extremely low birth weight (<1000 g; 60 dexamethasone-treated; 54 untreated) and 108 term-born. Data were analyzed using multivariate methods.

RESULT

Preterm performed below term-born on all measures. Dexamethasone-treated performed below dexamethasone-untreated in immediate visual memory, visual-motor integration, mathematical skill and motor dexterity. However, stepwise regression indicated that medical and sociodemographic factors other than dexamethasone contributed to preterm group differences.

CONCLUSION

Dexamethasone alone does not explain neurocognitive impairment in preterm children. Medical and sociodemographic factors (illness severity, male gender and parental education) are influential. Prospective longitudinal neuropsychological and behavioral study from preschool to school age that considers medical and sociodemographic variables will best address effects of dexamethasone exposure.

Neonatal correlates of adverse outcomes in very low-birthweight infants in the NICU Network

BACKGROUND

The aim of the present study was to explore the relationships among neonatal morbidity, interventions and death or adverse neurodevelopmental outcomes in very low-birthweight (VLBW) infants.

METHODS

Subjects were infants with birthweight ≤ 1500 g who were cared for in the tertiary neonatal intensive care units in Japan. Multiple logistic regression analysis was performed to examine the odds ratios (OR) and 95% confidence intervals (CI) of neonatal factors for death or cerebral palsy (CP) and death or developmental delay (developmental quotient <70 or delay judged by physicians) at 3 years of age after adjusting for biological and prenatal variables.

RESULTS

Of the 3104 subjects, 257 died and 1826 were evaluated at 3 years of age. Cystic periventricular leukomalacia (PVL; OR, 23.9; 95%CI: 11.0-51.7), gastrointestinal perforation (OR, 8.5; 95%CI: 2.8-25.4), intraventricular hemorrhage (IVH) grade 3 or 4 (OR, 3.1; 95%CI: 1.3-7.2) and sepsis (OR, 2.6; 95%CI: 1.4-4.8) were neonatal factors significantly associated with an increased risk of death or CP. Significant correlates with death or developmental delay were cystic PVL (OR, 7.9; 95%CI: 3.7-16.8), gastrointestinal perforation (OR, 6.3; 95%CI: 1.9-20.8), sepsis (OR, 2.8; 95%CI: 1.6-4.8), IVH grade 3 or 4 (OR, 2.6; 95%CI: 1.2-5.7), chronic lung disease at 36 weeks of corrected gestational age (OR, 1.6; 95%CI: 1.1-2.4) and treatment for retinopathy of prematurity (ROP; OR, 1.5; 95%CI: 1.0-2.3).

CONCLUSION

Cystic PVL, gastrointestinal perforation, IVH and sepsis correlated with both death or CP and death or developmental delay in VLBW infants. Chronic lung disease at 36 weeks and treatment for ROP were associated with death or developmental delay, but not with death or CP.

Systemic Hydrocortisone To Prevent Bronchopulmonary Dysplasia in preterm infants (the SToP-BPD study); a multicenter randomized placebo controlled trial

Background

Randomized controlled trials have shown that treatment of chronically ventilated preterm infants after the first week of life with dexamethasone reduces the incidence of the combined outcome death or bronchopulmonary dysplasia (BPD). However, there are concerns that dexamethasone may increase the risk of adverse neurodevelopmental outcome. Hydrocortisone has been suggested as an alternative therapy. So far no randomized controlled trial has investigated its efficacy when administered after the first week of life to ventilated preterm infants.

Methods/Design

The SToP-BPD trial is a randomized double blind placebo controlled multicenter study including 400 very low birth weight infants (gestational age < 30 weeks and/or birth weight < 1250 grams), who are ventilator dependent at a postnatal age of 7 - 14 days. Hydrocortisone (cumulative dose 72.5 mg/kg) or placebo is administered during a 22 day tapering schedule. Primary outcome measure is the combined outcome mortality or BPD at 36 weeks postmenstrual age. Secondary outcomes are short term effects on the pulmonary condition, adverse effects during hospitalization, and long-term neurodevelopmental sequelae assessed at 2 years corrected gestational age. Analysis will be on an intention to treat basis.

Discussion

This trial will determine the efficacy and safety of postnatal hydrocortisone administration at a moderately early postnatal onset compared to placebo for the reduction of the combined outcome mortality and BPD at 36 weeks postmenstrual age in ventilator dependent preterm infants.

Trial registration number

Netherlands Trial Register (NTR): NTR2768

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.

Repeated antenatal corticosteroid treatments adversely affect neural transmission time and auditory thresholds in laboratory rats

Antenatal corticosteroid (AC) treatment is given to pregnant women at risk for preterm birth to reduce infant morbidity and mortality by enhancing lung and brain maturation. However, there is no accepted regimen on how frequently AC treatments should be given and some studies found that repeated AC treatments can cause growth retardation and brain damage. Our goal was to assess the dose-dependent effects of repeated AC treatment and estimate the critical number of AC courses to cause harmful effects on the auditory brainstem response (ABR), a sensitive measure of brain development, neural transmission and hearing loss. We hypothesized that repeated AC treatment would have harmful effects on the offspring's ABRs and growth only if more than 3 AC treatment courses were given. To test this hypothesis, pregnant Wistar rats were given either a high regimen of AC (HAC), a moderate regimen (MAC), a low regimen (LAC), or saline (SAL). An untreated control (CON) group was also used. Simulating the clinical condition, the HAC dams received 0.2mg/kg Betamethasone (IM) twice daily for 6 days during gestation days (GD) 17-22. The MAC dams received 3 days of AC treatment followed by 3 days of saline treatment on GD 17-19 and GD 20-22, respectively. The LAC dams received 1 day of AC treatment followed by 5 days of saline treatment on GD 17 and GD 18-22, respectively. The SAL dams received 6 days of saline treatment from GD 17 to 22 (twice daily, isovolumetric to the HAC injections, IM). The offspring were ABR-tested on postnatal day 24. Results indicated that the ABR's P4 latencies (neural transmission time) were significantly prolonged (worse) in the HAC pups and that ABR's thresholds were significantly elevated (worse) in the HAC and MAC pups when compared to the CON pups. The HAC and MAC pups were also growth retarded and had higher postnatal mortality than the CON pups. The SAL and LAC pups showed little or no adverse effects. In conclusion, repeated AC treatment had harmful effects on the rat offspring's ABRs, postnatal growth and survival. The prolonged ABR latencies reflect slowed neural transmission times along the auditory nerve and brainstem auditory pathway. The elevated ABR thresholds reflect hearing deficits. We concluded that repeated AC treatment can have harmful neurological, sensory and developmental effects on the rat offspring. These effects should be considered when weighing the benefits and risks of repeated AC treatment and when monitoring and managing the prenatally exposed child for possible adverse effects.

Adjunctive oral methylprednisolone in pediatric acute pyelonephritis alleviates renal scarring

OBJECTIVE

To determine if glucocorticoids can prevent renal scar formation after acute pyelonephritis in pediatric patients.

METHODS

Patients younger than 16 years diagnosed with their first episode of acute pyelonephritis with a high risk of renal scar formation (ie, inflammatory volume ≥ 4.6 mL on technetium-99m-labeled dimercaptosuccinic acid scan [DMSA] or abnormal renal ultrasonography results) were randomly assigned to receive either antibiotics plus methylprednisolone sodium phosphate (1.6 mg/kg per day for 3 days [MPD group]) or antibiotics plus placebo (placebo group) every 6 hours for 3 days. Patients were reassessed by using DMSA 6 months after treatment. The primary outcome was the development of renal scars.

RESULTS

A total of 84 patients were enrolled: 19 in the MPD group and 65 in the placebo group. Patient characteristics were similar between the 2 groups, including the acute inflammatory parameters and the initial DMSA result. Renal scarring was found in 33.3% of children treated with MPD and in 60.0% of those who received placebo (P < .05). The median cortical defect volumes on follow-up DMSA were 0.0 mL (range: 0-4.5 mL) and 1.5 mL (range: 0-14.8 mL) for the MPD and placebo groups, respectively (P < .01). Patients in the MPD group experienced faster defervescence after treatment than the placebo group.

CONCLUSIONS

Adjunctive oral MPD therapy reduced the occurrence and/or severity of renal scarring after acute pyelonephritis in these hospitalized children who had a high risk of renal scar formation.

Mimicking maternal smoking and pharmacotherapy of preterm labor: fetal nicotine exposure enhances the effect of late gestational dexamethasone treatment on noradrenergic circuits

Smoking during pregnancy increases the risk of preterm delivery, which in turn necessitates the common use of glucocorticoids to prevent respiratory distress syndrome. Accordingly, there is a substantial population exposed conjointly to fetal nicotine and glucocorticoids (typically dexamethasone). We administered nicotine to pregnant rats throughout gestation, using a regimen (3 mg/kg/day by osmotic minipump) that maintains plasma nicotine levels within the range seen in smokers; on gestational days 17, 18 and 19, we gave 0.2 mg/kg of dexamethasone. We assessed norepinephrine levels in three brain regions (frontal/parietal cortex, brainstem, cerebellum) throughout adolescence, young adulthood and later adulthood, and contrasted the persistent effects with comparable measures in peripheral tissues (heart, liver). In adolescence, males showed initial deficits in the frontal/parietal cortex with either dexamethasone alone or the combined treatment, with resolution to normal by young adulthood; the group exposed to both nicotine+dexamethasone showed subsequent elevations that emerged in full adulthood and persisted through five months of age, an effect not seen with either agent separately. In females, the combined exposure produced an initial deficit that resolved by young adulthood, without any late-emerging changes. We did not see comparable effects in the other brain regions or peripheral tissues. This indicates that nicotine exposure sensitizes the developing brain to the adverse effects of dexamethasone treatment, producing sex-selective changes in innervation and/or activity of specific noradrenergic circuits. The fact that the combined treatment produced greater effects points to potentially worsened neurobehavioral outcomes after pharmacotherapy of preterm labor in the offspring of smokers.

Evidence for catch-up in cognition and receptive vocabulary among adolescents born very preterm

BACKGROUND

Very preterm adolescents display persistent deficits in neuropsychological functions.

OBJECTIVE

To compare cognitive and language outcomes at 16 years and cognitive and receptive vocabulary trajectories throughout school years between very preterm and term children and to determine child and family factors associated with better developmental trajectories.

DESIGN AND METHODS

At 8, 12, and 16 years, 322 very preterm children with birth weights of 1250 g or less and 41 term children had cognitive and language testing. Hierarchical growth-curve modeling was used to delineate the differences in cognitive and receptive vocabulary development between participants. Cluster analyses allowed for the characterization of very preterm children with different patterns of cognitive and receptive vocabulary development.

RESULTS

At 16 years, very preterm adolescents had deficits in general cognition and higher-order language skills (phonological awareness and phonemic decoding) compared with term peers. Although the between-group difference in cognitive scores remained stable from 8 to 16 years, very preterm children demonstrated catch-up gains in receptive vocabulary during the same period. Moreover, subgroups of very preterm children displayed developmental trajectories in cognition similar to term children (55% on the vocabulary and 46% on the block-design subtests). These children had lower rates of neurosensory impairment and mothers with higher education and were from an ethnic nonminority.

CONCLUSIONS

Significant catch-up in receptive vocabulary is observed by the age of 16 years among very preterm children compared to term peers. The absence of neurosensory impairment and residing in a favorable socioeconomic milieu are associated with the most optimal developmental trajectories.

Postnatal corticosteroids to treat or prevent chronic lung disease in preterm infants

This statement is intended for health care professionals caring for neonates and young infants. The objectives of this statement are to review the short and long term effects of systemic and inhaled postnatal corticosteroids for the prevention or treatment of evolving or established chronic lung disease, and to make recommendations for the use of corticosteroids in infants with very low birth weight. The routine use of systemic dexamethasone for the prevention or treatment of chronic lung disease in infants with very low birth weight is not recommended.

Postnatal steroids for the treatment of bronchopulmonary dysplasia: a complex case presentation

Postnatal steroids are a controversial intervention for the prevention and treatment of bronchopulmonary dysplasia in preterm infants. Studies demonstrating a potential for steroid-related adverse effects, including growth and neurodevelopmental impairment, have significantly changed clinical practice over the past decade. There are circumstances in which the potential benefits may outweigh the risks associated with postnatal steroids. This case presentation details the hospital course and treatment plan for an extremely low-birth-weight infant who remained ventilator dependent at the age of 3 weeks. Evidence-based research, American Academy of Pediatric recommendations, and collaboration with the family helped guide the plan of care. Following a short course of low-dose dexamethasone, the infant was successfully extubated. The case highlights the importance of using clinical judgment based on research and family preferences to benefit the patient.

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.

Serum chemokine levels and developmental outcome in preterm infants

BACKGROUND

Cytokines and chemokines during perinatal period may involve the neurological development of newborns.

AIMS

We investigated the association of circulating chemokines during neonatal period with the outcome of premature infants.

STUDY DESIGN

The prospective study enrolled 29 very low birth weight (<1500 g) and appropriate-for-date infants having no underlying diseases. Serum concentrations of chemokines (CXCL8, CXCL9, CXCL10 and CCL2) and cytokines at birth and 4 weeks postnatal age were measured. Developmental quotients (DQ) at 3 years of age by the Kyoto Scale of Psychological Development were studied for the association with chemokine/cytokine levels and clinical variables including chorioamnionitis, Apgar scores, ventilator treatment and supplemental oxygen.

RESULTS

CXCL8 levels at birth and days of ventilator treatment were negatively, CCL2 levels at 4 weeks after birth and 5-minute Apgar scores were positively correlated with the DQ of postural-motor [P-M] area at 3 years of age, respectively (CXCL8: correlation coefficient [CC]=-0.394, p=0.037, ventilation: CC=-0.518, p=0.006, CCL2: CC=0.528, p=0.013, and Apgar score: CC=0.521, p=0.005). Infants showing both ≥50 pg/ml of CXCL8 at birth and <250 pg/ml of CCL2 4 weeks after birth had lower DQ of P-M than those who did not (p<0.001). Multivariate analyses indicated that CCL2 levels at 4 weeks of age were higher in infants who attained normal DQ of P-M (≥85) (adjusted mean, 338.4 [95% confidence interval, 225.5-507.8]) than in those who did not (<85) (159.0, [108.2-233.7]) (p=0.019).

CONCLUSION

Circulating patterns of CXCL8 (IL-8) and CCL2 (MCP-1) during the neonatal period might affect the neurological development of preterm infants.

Bronchopulmonary Dysplasia: Development and Progression in the Neonatal Intensive Care Unit

Advances in neonatology have led to increased survival at younger gestational ages. These advances have included the ability to provide and titrate oxygen, improved modalities of assisted ventilation, improved nutritional and environmental support, and surfactant therapy. As a result of increasing survival of these immature infants, bronchopulmonary dysplasia (BPD) has become a consistent outcome despite improvements in technology. Varying definitions of BPD have emerged in an effort to best identify infants at risk for long-term adverse outcome and those who might benefit most from preventive therapies. Underlying abnormal pulmonary development of extremely preterm infants in the face of exposure to oxygen, assisted ventilation and inflammation make this a complex, multifactorial disease. Recent focus has been directed at preventing and treating inflammation. Efforts to minimize the inflammatory process include avoiding hyperoxia, minimizing injury from assisted ventilation, and preventing and treating postnatal infections. Additional therapies to modulate inflammation, such as steroid therapy or inhaled nitric oxide, need further investigation of both short- and long-term outcomes before routine use can be recommended.

Fluconazole prophylaxis in extremely low birth weight infants and neurodevelopmental outcomes and quality of life at 8 to 10 years of age

OBJECTIVE

To examine the long-term effects of fluconazole prophylaxis in extremely low birth weight infants.

STUDY DESIGN

Neurodevelopmental status and quality of life of survivors from a randomized, placebo-controlled trial of fluconazole prophylaxis were evaluated at 8 to 10 years of life using the Vineland Adaptive Behavior Scales-II (VABS-II) and the Child Health Questionnaire Parent-Completed Form 28 (CHQ-PF28), respectively.

RESULTS

VABS-II Domain Scores for the fluconazole-treated (n = 21; 9.1 ± 0.7 years) compared with the placebo group (n = 17; 9.3 ± 0.8 years) were similar for communication [94.6 (±14.8) versus 92.6 (±12.6), P = .65], daily living skills [87.9 (±10.6) versus 87.4 (±9.3), P = .89], socialization [97.2 (±9.2) versus 94.4 (±7.9), P = .31], and motor skills [92.1 (±17.8) versus 95.1 (±14.6), P = .57]. Internalizing and externalizing behaviors and maladaptive behavior index were also similar. The CHQ-PF28 revealed no differences between the two groups regarding quality of life. Survivors were also happy or satisfied with school (90% versus 100%, P = .49), friendships (90% versus 88%, P = 1.00), and life (95% versus 100%, P = 1.00). Self esteem scores were 87.3 ± 15.7 versus 89.7 ± 10.4 (P = .59). There were also no differences between groups regarding emotional difficulties or behavior problems.

CONCLUSIONS

Fluconazole prophylaxis for the prevention of invasive Candida infections is safe in extremely low birth weight infants and does not appear to be associated with any long-term adverse effects on neurodevelopment and quality of life at 8 to 10 years of life.

Disrupted postnatal lung development in heme oxygenase-1 deficient mice

Background

Heme oxygenase (HO) degrades cellular heme to carbon monoxide, iron and biliverdin. The HO-1 isoform is both inducible and cyto-protective during oxidative stress, inflammation and lung injury. However, little is known about its precise role and function in lung development. We hypothesized that HO-1 is required for mouse postnatal lung alveolar development and that vascular expression of HO-1 is essential and protective during postnatal alveolar development.

Methods

Neonatal lung development in wildtype and HO-1 mutant mice was evaluated by histological and molecular methods. Furthermore, these newborn mice were treated with postnatal dexamethasone (Dex) till postnatal 14 days, and evaluated for lung development.

Results

Compared to wildtype littermates, HO-1 mutant mice exhibited disrupted lung alveolar structure including simplification, disorganization and reduced secondary crest formation. These defects in alveolar development were more pronounced when these mice were challenged with Dex treatment. Expression levels of both vascular endothelial and alveolar epithelial markers were also further decreased in HO-1 mutants after Dex treatment.

Conclusions

These experiments demonstrate that HO-1 is required in normal lung development and that HO-1 disruption and dexamethasone exposure are additive in the disruption of postnatal lung growth. We speculate that HO-1 is involved in postnatal lung development through modulation of pulmonary vascular development.

Open-label glucocorticoids modulate dexamethasone trial results in preterm infants

CONTEXT

Open-label glucocorticoids (OLGs) were often used in trials that investigated postnatal dexamethasone treatment in ventilated preterm infants.

OBJECTIVE

To determine if OLG use modulates the dexamethasone treatment effect on mortality, bronchopulmonary dysplasia (BPD), and neurodevelopmental outcome.

METHODS

Electronic databases, abstracts from the Pediatric Academic Societies, and results of manual reference searches were used as data sources. Fifteen randomized controlled trials comparing dexamethasone with placebo in 721 ventilated preterm infants older than 7 days were identified. The interaction between dexamethasone treatment effect and OLG use was assessed by meta-regression analysis and subgroup meta-analysis according to the percentage of OLG use in the placebo group. Trials with a moderately early (7- to 14-day) or delayed (>3-week) treatment onset were analyzed separately.

RESULTS

Moderately early, but not delayed, dexamethasone treatment significantly reduced mortality rates in trials with OLG use at <30% in the placebo arm. Meta-regression analysis revealed that this reduction was inversely related to OLG use. Increasing OLG use strengthened the positive effect of dexamethasone on BPD in the moderately early trials but attenuated the effect in the delayed-treatment trials. In trials with <30% OLG use, dexamethasone increased the risk for cerebral palsy in the delayed, but not the moderately early, treatment trials.

CONCLUSIONS

When OLG use is taken into account moderately early dexamethasone treatment reduced mortality rates and the combined outcome mortality and BPD without increasing the risk of adverse neurodevelopmental outcome in ventilated preterm infants. A large randomized controlled trial is needed to confirm or refute these findings.

Policy statement--postnatal corticosteroids to prevent or treat bronchopulmonary dysplasia

The purpose of this revised statement is to review current information on the use of postnatal glucocorticoids to prevent or treat bronchopulmonary dysplasia in the preterm infant and to make updated recommendations regarding their use. High-dose dexamethasone (0.5 mg/kg per day) does not seem to confer additional therapeutic benefit over lower doses and is not recommended. Evidence is insufficient to make a recommendation regarding other glucocorticoid doses and preparations. The clinician must use clinical judgment when attempting to balance the potential adverse effects of glucocorticoid treatment with those of bronchopulmonary dysplasia.

The role of growth retardation in lasting effects of neonatal dexamethasone treatment on hippocampal synaptic function

BACKGROUND

Dexamethasone (DEX), a synthetic glucocorticoid, is commonly used to prevent or lessen the morbidity of chronic lung disease in preterm infants. However, evidence is now increasing that this clinical practice negatively affects somatic growth and may result in long-lasting neurodevelopmental deficits. We therefore hypothesized that supporting normal somatic growth may overcome the lasting adverse effects of neonatal DEX treatment on hippocampal function.

METHODOLOGY/PRINCIPAL FINDINGS

To test this hypothesis, we developed a rat model using a schedule of tapering doses of DEX similar to that used in premature infants and examined whether the lasting influence of neonatal DEX treatment on hippocampal synaptic plasticity and memory performance are correlated with the deficits in somatic growth. We confirmed that neonatal DEX treatment switched the direction of synaptic plasticity in hippocampal CA1 region, favoring low-frequency stimulation- and group I metabotropic glutamate receptor agonist (S)-3,5,-dihydroxyphenylglycine-induced long-term depression (LTD), and opposing the induction of long-term potentiation (LTP) by high-frequency stimulation in the adolescent period. The effects of DEX on LTP and LTD were correlated with an increase in the autophosphorylation of Ca(2+)/calmodulin-dependent protein kinase II at threonine-286 and a decrease in the protein phosphatase 1 expression. Neonatal DEX treatment resulted in a disruption of memory retention subjected to object recognition task and passive avoidance learning. The adverse effects of neonatal DEX treatment on hippocampal synaptic plasticity and memory performance of the animals from litters culled to 4 pups were significantly less than those for the 8-pup litters. However, there was no significant difference in maternal care between groups.

CONCLUSION/SIGNIFICANCE

Our results demonstrate that growth retardation plays a crucial role in DEX-induced long-lasting influence of hippocampal function. Our findings suggest that therapeutic strategies designed to support normal development and somatic growth may exert beneficial effects to reduce lasting adverse effects following neonatal DEX treatment.

Motor trajectories from 4 to 18 months corrected age in infants born at less than 30 weeks of gestation

BACKGROUND

Preterm infants are recognised as developing at a significantly slower rate than their full-term peers and with different movement quality.

AIM

This study aimed to describe the longitudinal gross motor trajectories of these infants in the first 18 months of (corrected) age and investigate factors associated with gross motor development.

STUDY DESIGN

A longitudinal study was conducted with convenience samples of 58 preterm infants born < or = 29 weeks of gestation and 52 control full-term infants in Australia.

OUTCOME MEASURES

The infants were assessed at 4, 8, 12 and 18 months of (corrected) age using the Alberta Infant Motor Scale (AIMS).

RESULTS

Forty-six preterm and 48 control infants completed all four assessments. The preterm group scored significantly lower on various sub-scores at all age levels. Almost half of the preterm infants demonstrated less progression in the sit sub-scale from 4 to 8 months (corrected) age, possibly due to an imbalance between flexor and extensor strength in the trunk. At 12 and 18 months of (corrected) age, lack of rotation and fluency in their movements were evident in some preterm infants. Presence of intra-ventricular haemorrhage and chronic lung disease were associated with poor motor performance at 4 months and use of postnatal steroids was associated with poor motor performance at 4, 8 and 18 months of corrected age.

CONCLUSION

The imbalance between flexor and extensor muscle strength in preterm infants had a stronger impact on motor development than usually expected. The AIMS appears to be a sensitive assessment tool to demonstrate the unique movement characteristics in this preterm cohort.

Two-year neurodevelopmental outcomes of ventilated preterm infants treated with inhaled nitric oxide

OBJECTIVE

In a randomized multi-center trial, we demonstrated that inhaled nitric oxide begun between 7 and 21 days and given for 24 days significantly increased survival without bronchopulmonary dysplasia (BPD) in ventilated premature infants weighing <1250 g. Because some preventative BPD treatments are associated with neurodevelopmental impairment, we designed a follow-up study to assess the safety of nitric oxide.

STUDY DESIGN

Our hypothesis was that inhaled nitric oxide would not increase neurodevelopmental impairment compared with placebo. We prospectively evaluated neurodevelopmental and growth outcomes at 24 months postmenstrual age in 477 of 535 surviving infants (89%) enrolled in the trial.

RESULTS

In the treated group, 109 of 243 children (45%) had neurodevelopmental impairment (moderate or severe cerebral palsy, bilateral blindness, bilateral hearing loss, or score <70 on the Bayley Scales II), compared with 114 of 234 (49%) in the placebo group (relative risk, 0.92; 95% CI, 0.75-1.12; P = .39). No differences on any subcomponent of neurodevelopmental impairment or growth variables were found between inhaled nitric oxide or placebo.

CONCLUSIONS

Inhaled nitric oxide improved survival free of BPD, with no adverse neurodevelopmental effects at 2 years of age.

Mimicking maternal smoking and pharmacotherapy of preterm labor: interactions of fetal nicotine and dexamethasone on serotonin and dopamine synaptic function in adolescence and adulthood

Fetal coexposure to nicotine and dexamethasone is common: maternal smoking increases the incidence of preterm delivery and glucocorticoids are the consensus treatment for prematurity. We gave pregnant rats 3mg/kg/day of nicotine throughout gestation, a regimen that reproduces smokers' plasma levels, and then on gestational days 17, 18 and 19, we administered 0.2mg/kg of dexamethasone. We evaluated developmental indices for serotonin (5HT) and dopamine synaptic function throughout adolescence, young adulthood and later adulthood, assessing the brain regions possessing major 5HT and dopamine projections and cell bodies. Males displayed persistent upregulation of 5HT(1A) and 5HT(2) receptors and the 5HT transporter, with a distinct hierarchy of effects: nicotine<dexamethasone<combined treatment. Females showed downregulation of the 5HT(1A) receptor with the same rank order; both sexes displayed presynaptic hyperactivity of 5HT and dopamine pathways as evidenced by increased neurotransmitter turnover. Superimposed on these overall effects, there were significant differences in temporal and regional relationships among the different treatments, often involving effects that emerged later in life, after a period of apparent normality. This indicates that nicotine and dexamethasone do not simply produce an initial neuronal injury that persists throughout the lifespan but rather, they alter the developmental trajectory of synaptic function. The fact that the combined treatment produced greater effects for many parameters points to potentially worse neurobehavioral outcomes after pharmacotherapy of preterm labor in the offspring of smokers.

Neuroprotective effects vary across nonsteroidal antiinflammatory drugs in a mouse model of developing excitotoxic brain injury

Glutamate excitotoxicity is among the main cellular mechanisms leading to perinatal insults in human newborns. We used intracerebral injection of the glutamatergic glutamate N-methyl-D-aspartate-receptor agonist ibotenate to produce excitotoxic lesions mimicking the acquired white matter lesions seen in human preterm infants. We evaluated whether nonsteroidal antiinflammatory drugs (NSAIDs) protected against glutamate excitotoxicity. Aspirin (0.01-100 microg/d), indomethacin (0.1-10 microg/d), paracetamol (10-100 microg/d), or NS-398 (12.5 microg/d) was given daily before ibotenate (P1 to P5) or after ibotenate (P5 to P9). Lesion size was measured on Cresyl Violet-stained brain sections collected on P10. None of the drugs tested alone or in combination increased lesion size. Pretreatment with low- or high-dose aspirin and post-treatment with paracetamol or NS-398 protected against white matter lesions, whereas cortical lesions were decreased by pretreatment with low- or high-dose aspirin or post-treatment with NS-398. The corticosteroid betamethasone (0.18 microg/d) was neuroprotective when given before or after ibotenate and this effect was reversed by concomitant aspirin therapy (10 microg/d). In conclusion, perinatal NSAID administration may have beneficial effects on brain injury if appropriately timed.

Vulnerability to stroke: implications of perinatal programming of the hypothalamic-pituitary-adrenal axis

Chronic stress is capable of exacerbating each major, modifiable, endogenous risk factor for cerebrovascular and cardiovascular disease. Indeed, exposure to stress can increase both the incidence and severity of stroke, presumably through activation of the hypothalamic-pituitary-adrenal (HPA) axis. Now that characterization of the mechanisms underlying epigenetic programming of the HPA axis is well underway, there has been renewed interest in examining the role of early environment on the evolution of health conditions across the entire lifespan. Indeed, neonatal manipulations in rodents that reduce stress responsivity, and subsequent life-time exposure to glucocorticoids, are associated with a reduction in the development of neuroendocrine, neuroanatomical, and cognitive dysfunctions that typically progress with age. Although improved day to day regulation of the HPA axis also may be accompanied by a decrease in stroke risk, evidence from rodent studies suggest that an associated cost could be increased susceptibility to inflammation and neuronal death in the event that a stroke does occur and the individual is exposed to persistently elevated corticosteroids. Given its importance in regulation of health and disease states, any long-term modulation of the HPA axis is likely to be associated with both benefits and potential risks. The goals of this review article are to examine (1) the clinical and experimental data suggesting that neonatal experiences can shape HPA axis regulation, (2) the influence of stress and the HPA axis on stroke incidence and severity, and (3) the potential for neonatal programming of the HPA axis to impact adult cerebrovascular health.

Cerebellum of the premature infant: rapidly developing, vulnerable, clinically important

Brain abnormality in surviving premature infants is associated with an enormous amount of neurodevelopmental disability, manifested principally by cognitive, behavioral, attentional, and socialization deficits, most commonly with only relatively modest motor deficits. The most recognized contributing neuropathology is cerebral white matter injury. The thesis of this review is that acquired cerebellar abnormality is a relatively less recognized but likely important cause of neurodevelopmental disability in small premature infants. The cerebellar disease may be primarily destructive (eg, hemorrhage, infarction) or primarily underdevelopment. The latter appears to be especially common and relates to a particular vulnerability of the cerebellum of the small premature infant. Central to this vulnerability are the extraordinarily rapid and complex developmental events occurring in the cerebellum. The disturbance of development can be caused either by direct adverse effects on the cerebellum, especially the distinctive transient external granular layer, or by indirect remote trans-synaptic effects. This review describes the fascinating details of cerebellar development, with an emphasis on events in the premature period, the major types of cerebellar abnormality acquired during the premature period, their likely mechanisms of occurrence, and new insights into the relation of cerebellar disease in early life to subsequent cognitive/behavioral/attentional/socialization deficits.

Time-related changes in steroid use and bronchopulmonary dysplasia in preterm infants

OBJECTIVE

To assess dexamethasone (DEX) and hydrocortisone (HC) use in premature infants over time and the association of steroid use with the incidence of bronchopulmonary dysplasia (BPD) at 36 weeks' postmenstrual age.

METHODS

We analyzed data from the Pediatrix database for neonates of 23 to 32 weeks' gestation managed during 1997-2006 (N = 77520). We compared the use of DEX, HC and BPD (defined by oxygen use at 36 weeks' postmenstrual age) according to year and estimated gestational age. Mantel-Haenszel chi(2) was used to compare the trends in steroid use and BPD rates according to year.

RESULTS

There were no differences by year in the proportion of births at each gestation or in early or late neonatal death. DEX use decreased from a peak of 25.0% in 1998 to 6.8% in 2006, but HC use increased from 1.1% in 1997 to a peak of 6.5% in 2006. The median age at initiation of DEX use increased >2 weeks from 1997 to 2006. BPD rates increased from 19% in 1997 to 25% by 2006. Rates for severe BPD (defined by positive pressure support) also increased significantly over time. Between 23 and 28 weeks, there was a significant increase in BPD rates associated with the decrease in DEX over time.

CONCLUSIONS

Steroid use and preference have changed significantly over the past decade. Decreased use of DEX was associated with increased rates of BPD, any or severe, among very preterm infants. Well-designed, randomized, noncrossover trials with long-term outcome analysis of high-risk infants are needed.