Hydrocortisone treatment for bronchopulmonary dysplasia and brain volumes in preterm infants

Early low-dose hydrocortisone is associated with a reduced risk of bronchopulmonary dysplasia in infants born at less than 26 weeks' gestational age

Objective

To determine whether administering low-dose hydrocortisone early in treatment reduces the risk of bronchopulmonary dysplasia (BPD) in infants born before 26 weeks of gestation.

Study design

This retrospective case-control study compared the incidence of Grade II+ BPD between infants who received hydrocortisone treatment and those who did not. Propensity score matching was used to ensure comparability between the groups, with a 1:1 match ratio based on gestational age and birth weight.

Results

A total of 66 infants were included in the study. Those who received early low-dose hydrocortisone demonstrated a significantly lower risk of Grade II+ BPD incidence (p = 0.024). Additionally, early administration of low-dose hydrocortisone was associated with a shorter duration of non-invasive ventilation days (p = 0.038). Multiple logistic regression analysis confirmed that hydrocortisone treatment was independently associated with a reduced risk of Grade II + BPD incidence (OR: 0.287, 95% CI: 0.084-0.980).

Conclusions

These findings suggest that early administration of low-dose hydrocortisone is associated with a reduced risk of Grade II+ BPD in extremely preterm infants born before 26 weeks of gestation.

Hydrocortisone in very preterm neonates for BPD prevention: meta-analysis and effect size modifiers

OBJECTIVES

To clarify if systemic hydrocortisone, in protocols allowing to start it before the 15th day of life, prevents bronchopulmonary dysplasia (BPD) or other adverse outcomes in very preterm neonates, and to identify any possible effect size modifiers.

STUDY DESIGN

Systematic review and meta-analysis following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Additional analyses included meta-regressions and review of biological plausibility.

RESULTS

Seven trials were included, they were of general good quality and accounted for a total of 2193 infants. Hydrocortisone treatment did not reduce BPD (risk ratio (RR) 0.84 (95% CI 0.64 to 1.04)), but heterogeneity was evident (I2=51.6%). The effect size for BPD is greatest for 10-12 days duration of treatment (β=0.032 (0.01), p=0.007) and tended to be greater in patients with chorioamnionitis (β=-1.5 (0.841), p=0.07). Hydrocortisone treatment may significantly reduce mortality (RR 0.75 (95% CI 0.59 to 0.91)), there is no heterogeneity (I2=0) and the reduction tended to be greater in males (β=-0.06 (0.03), p=0.07). Hydrocortisone may significantly reduce necrotising enterocolitis (NEC; RR 0.72 (95% CI 0.53 to 0.92)); there is neither heterogeneity (I2=0%) nor any effect size modifiers. Hydrocortisone did not affect other adverse outcomes of prematurity.

CONCLUSIONS

Systemic hydrocortisone may be considered, on a case-by-case evaluation, to reduce mortality and NEC, while it does not affect BPD. There are some potential effect size modifiers for mortality and BPD which should be addressed in future explanatory trials.

PROSPERO REGISTRATION NUMBER

CRD42023400520.

Severe Bronchopulmonary Dysplasia Adversely Affects Brain Growth in Preterm Infants

INTRODUCTION

Bronchopulmonary dysplasia (BPD) is associated with neurodevelopmental outcomes of preterm infants, but its effect on brain growth in preterm infants after the neonatal period is unknown. This study aimed to evaluate the effect of severe BPD on brain growth of preterm infants from term to 18 months of corrected age (CA).

METHODS

Sixty-three preterm infants (42 with severe BPD and 21 without severe BPD) who underwent magnetic resonance imaging at term equivalent age (TEA) and 18 months of CA were studied by using the Infant Brain Extraction and Analysis Toolbox (iBEAT). We measured segmented brain volumes and compared brain volume and brain growth velocity between the severe BPD group and the non-severe BPD group.

RESULTS

There was no significant difference in brain volumes at TEA between the groups. However, the brain volumes of the total brain and cerebral white matter in the severe BPD group were significantly smaller than those in the non-severe BPD group at 18 months of CA. The brain growth velocities from TEA to 18 months of CA in the total brain, cerebral cortex, and cerebral white matter in the severe BPD group were lower than those in the non-severe BPD group.

CONCLUSION

Brain growth in preterm infants with severe BPD from TEA age to 18 months of CA is less than that in preterm infants without severe BPD.

Early, low-dose hydrocortisone and near-term brain connectivity in extremely preterm infants

BACKGROUND

Postnatal steroids are used to prevent bronchopulmonary dysplasia in extremely preterm infants but may have adverse effects on brain development. We assessed connectivity metrics of major cerebral and cerebellar white matter pathways at near-term gestational age among infants who did or did not receive a standardized regimen of hydrocortisone during the first 10 days of life.

METHODS

Retrospective cohort study.

PARTICIPANTS

Infants born <28 weeks: Protocol group (n = 33) received at least 50% and not more than 150% of an intended standard dose of 0.5 mg/kg hydrocortisone twice daily for 7 days, then 0.5 mg/kg per day for 3 days; Non-Protocol group (n = 22), did not receive protocol hydrocortisone or completed <50% of the protocol dose. We assessed group differences in near-term diffusion MRI mean fractional anisotropy (FA) and mean diffusivity (MD) across the corticospinal tract, inferior longitudinal fasciculus, corpus callosum and superior cerebellar peduncle.

RESULTS

Groups were comparable in gestational age, post-menstrual age at scan, medical complications, bronchopulmonary dysplasia, and necrotizing enterocolitis. No significant large effect group differences were identified in mean FA or MD in any cerebral or cerebellar tract.

CONCLUSION(S)

Low dose, early, postnatal hydrocortisone was not associated with significant differences in white matter tract microstructure at near-term gestational age.

IMPACT

This study compared brain microstructural connectivity as a primary outcome among extremely preterm infants who did or did not receive early postnatal hydrocortisone. Low dose hydrocortisone in the first 10 days of life was not associated with significant differences in white matter microstructure in major cerebral and cerebellar pathways. Hydrocortisone did not have a significant effect on early brain white matter circuits.

Effect of Systemic Hydrocortisone on Brain Abnormalities and Regional Brain Volumes in Ventilator-dependent Infants Born Preterm: Substudy of the SToP-BPD Study

OBJECTIVE

To evaluate whether a high cumulative dose of systemic hydrocortisone affects brain development compared with placebo when initiated between 7 and 14 days after birth in ventilated infants born preterm.

STUDY DESIGN

A double-blind, placebo-controlled, randomized trial was conducted in 16 neonatal intensive care units among infants born at <30 weeks of gestation or with a birth weight of <1250 g who were ventilator-dependent in the second week after birth. Three centers performed MRI at term-equivalent age. Brain injury was assessed on MRI using the Kidokoro scoring system and compared between the 2 treatment groups. Both total and regional brain volumes were calculated using an automatic segmentation method and compared using multivariable regression analysis adjusted for baseline variables.

RESULTS

From the 3 centers, 78 infants participated in the study and 59 had acceptable MRI scans (hydrocortisone group, n = 31; placebo group, n = 28). Analyses of the median global brain abnormality score of the Kidokoro score showed no difference between the hydrocortisone and placebo groups (median, 7; IQR, 5-9 vs median, 8, IQR, 4-10, respectively; P = .92). In 39 infants, brain tissue volumes were measured, showing no differences in the adjusted mean total brain tissue volumes, at 352 ± 32 mL in the hydrocortisone group and 364 ± 51 mL in the placebo group (P = .80).

CONCLUSIONS

Systemic hydrocortisone started in the second week after birth in ventilator-dependent infants born very preterm was not found to be associated with significant differences in brain development compared with placebo treatment.

TRIAL REGISTRATION

The SToP-BPD study was registered with the Netherlands Trial Register (NTR2768; registered on 17 February 2011; https://www.trialregister.nl/trial/2640) and the European Union Clinical Trials Register (EudraCT, 2010-023777-19; registered on 2 November 2010; https://www.clinicaltrialsregister.eu/ctr-search/trial/2010-023777-19/NL).

Neurodevelopment in Term Infants with Normal Birthweight following Postnatal Systemic Steroid Exposure

INTRODUCTION

Studies investigating the potential impact of systemic steroid exposure during early infancy on neurological development in full-term infants with normal birth weight are lacking.

METHODS

This population-based administrative cohort study used data of national health insurance and a health-screening program for infants and children and included full-term infants who were born in Korea between 2008 and 2012 with normal birth weight and did not have any specific perinatal or neurodevelopmental diseases. The prescription of systemic steroids within the first 3 months of age was mainly considered. The neurological development of children was assessed using the Korean Development Screening Test (K-DST) at 6 years of age. To balance the baseline characteristics of the control and exposed groups, stabilized inverse probability of treatment weighting with trimming was performed in the main cohort. Ordinal logistic regression was used to assess the association between systemic steroid exposure and unfavorable results in the K-DST.

RESULTS

The control and exposure groups had 246,168 and 5,083 children, respectively. The K-DST suggested unfavorable results in 8.1% and 8.6% children in the control and exposure groups, respectively (weighted odds ratio, 95% confidence interval, 1.03, 0.93-1.14). When each domain of the K-DST was considered separately, the risk of unfavorable results in the exposed group was not significantly different from that in the control group.

CONCLUSIONS

No significant association was observed between exposure to systemic steroids during early infancy and neurodevelopmental impairment at 6 years of age.

Impact of Nutritional Status on Total Brain Tissue Volumes in Preterm Infants

Preterm infants bypass the crucial in utero period of brain development and are at increased risk of malnutrition. We aimed to determine if their nutritional status is associated with brain tissue volumes at term equivalent age (TEA), applying recently published malnutrition guidelines for preterm infants. We performed a single center retrospective chart review of 198 infants < 30 weeks' gestation between 2018 and 2021. We primarily analyzed the relationship between the manually obtained neonatal MR-based brain tissue volumes with the maximum weight and length z-score. Significant positive linear associations between brain tissue volumes at TEA and weight and length z-scores were found (p < 0.05). Recommended nutrient intake for preterm infants is not routinely achieved despite efforts to optimize nutrition. Neonatal MR-based brain tissue volumes of preterm infants could serve as objective, quantitative and reproducible surrogate parameters of early brain development. Nutrition is a modifiable factor affecting neurodevelopment and these results could perhaps be used as reference data for future timely nutritional interventions to promote optimal brain volume.

Preterm lung and brain responses to mechanical ventilation and corticosteroids

Mechanical ventilation is necessary to maintain oxygenation and ventilation in many preterm infants. Unfortunately, even short periods of mechanical ventilation can cause lung and airway injury, and initiate the lung inflammation that contributes to the development of bronchopulmonary dysplasia (BPD). The mechanical stretch leads to airway cell differentiation and simplification of the alveoli, and releases cytokines that cause systemic response in other organs. Mechanical ventilation also leads to brain injury (IVH, white and gray matter) and neuronal inflammation that can affect the neurodevelopment of preterm infants. In efforts to decrease BPD, corticosteroids have been used for both prevention and treatment of lung inflammation. Corticosteroids have also been demonstrated to cause neuronal injury, so the clinician must balance the negative effects of both mechanical ventilation and steroids on the brain and lungs. Predictive models for BPD can help assess the infants who will benefit most from corticosteroid exposure. This review describes the lung and brain injury from mechanical ventilation in the delivery room and chronic mechanical ventilation in animal models. It provides updates on the current guidelines for use of postnatal corticosteroids (dexamethasone, hydrocortisone, budesonide, budesonide with surfactant) for the prevention and treatment of BPD, and the effects the timing of each steroid regimen has on neurodevelopment.

The Association of Dexamethasone and Hydrocortisone with Cerebellar Growth in Premature Infants

OBJECTIVES

Corticosteroids are used to prevent or treat lung disease of prematurity. While neurological side effects have been reported, detailed effects on cerebellar growth are unknown. This study aimed to compare cerebellar growth in premature infants who received dexamethasone or hydrocortisone to premature infants who did not receive postnatal corticosteroids.

STUDY DESIGN

Retrospective case-control study in infants born at a gestational age of <29 weeks and admitted to two level 3 neonatal intensive care units. Exclusion criteria were severe congenital anomalies and cerebellar or severe supratentorial lesions. Infants were treated with dexamethasone (unit 1) or hydrocortisone (unit 2) for chronic lung disease. Controls (unit 1) did not receive postnatal corticosteroids. Sequential head circumference (HC) and ultrasound measurements of transcerebellar diameter (TCD), biparietal diameter (BPD), and corpus callosum-fastigium length (CCFL) were performed until 40 weeks' postmenstrual age (PMA). Growth was assessed using linear mixed models correcting for PMA at measurement, sex, HC z-score at birth, and a propensity score indicating illness severity. Group differences before treatment were assessed using linear regression.

RESULTS

346 infants were included (68 dexamethasone, 37 hydrocortisone, 241 controls). Before starting corticosteroids, TCD, BPD, and HC measurements did not differ between patients and controls at a comparable PMA. After starting treatment, both types of corticosteroid had a negative association with TCD growth. BPD, CCFL, and HC growth were not negatively affected.

CONCLUSION

Administration of dexamethasone and hydrocortisone are both associated with impaired cerebellar growth in premature infants without evident negative associations with cerebral growth.

Duration of mechanical ventilation is more critical for brain growth than postnatal hydrocortisone in extremely preterm infants

Hydrocortisone is used in preterm infants. However, early disruption of growth velocities was observed in infants exposed to hydrocortisone. This retrospective study aimed to explore the postnatal brain growth of extremely preterm infants requiring hydrocortisone treatment as well as its association with perinatal factors. Extremely preterm infants exposed to hydrocortisone from 2011 to 2016 who survived up to 12 months were included. Each of them was matched with two infants not treated with hydrocortisone exhibiting similar gestational ages and nearly similar birth head circumferences. The outcome variables were brain tissue areas on MRIs performed at term-equivalent age and postnatal head circumference growth up to a corrected age of 12 months. Univariate and multiple regression analyses were performed. Infants treated with hydrocortisone (n=20) were matched with 40 infants not exposed to hydrocortisone. The infants exposed to hydrocortisone exhibited a lower birth weight (p=0.04) and a longer duration of mechanical ventilation (p<0.0001). Infants treated with hydrocortisone exhibited a smaller basal ganglia/thalamus area (p=0.04) at term-equivalent age and a smaller head circumference at a corrected age of 12 months (p=0.003). However, the basal ganglia/thalamus area and the postnatal brain growth were independently associated with the duration of mechanical ventilation and not with hydrocortisone. Interestingly, a significant interaction between hydrocortisone and sex was observed (p=0.04).Conclusion: This study supports previous data that indicated no obvious impact of hydrocortisone on brain growth and highlights the relationship between the severity of the neonatal course and postnatal brain growth in extremely preterm infants. What is Known: • Postnatal hydrocortisone disrupts transiently growth velocities including the head circumference growth. • Postnatal hydrocortisone has less impact on neurodevelopment than dexamethasone. What is New: • Hydrocortisone prescribed for infants in the most severe conditions did not show independent effect on brain growth up to the corrected age of 12 months. However, a different effect of hydrocortisone according to sex can't be excluded and needs further explorations. • Perinatal factors as birth weight and duration of mechanical ventilation were determinant for the subsequent brain growth.

Corticosteroids for Neonatal Hypotension

Several limitations and controversies surround the definition of hypotension; however, it remains one of the most common problems faced by neonates. Approximately 15% to 30% of neonates with hypotension fail to respond to volume and/or vasopressor or inotropes. They are considered to have refractory hypotension. Although it is thought to have multiple causes, absolute and relative adrenal insufficiency is considered as the main reason for refractory hypotension. This article focuses on the role of adrenal insufficiency in causing refractory hypotension in preterm and term infants, the different options of corticosteroids available, and their risk/benefit profiles.

Preterm Brain Injury, Antenatal Triggers, and Therapeutics: Timing Is Key

With a worldwide incidence of 15 million cases, preterm birth is a major contributor to neonatal mortality and morbidity, and concomitant social and economic burden Preterm infants are predisposed to life-long neurological disorders due to the immaturity of the brain. The risks are inversely proportional to maturity at birth. In the majority of extremely preterm infants (<28 weeks' gestation), perinatal brain injury is associated with exposure to multiple inflammatory perinatal triggers that include antenatal infection (i.e., chorioamnionitis), hypoxia-ischemia, and various postnatal injurious triggers (i.e., oxidative stress, sepsis, mechanical ventilation, hemodynamic instability). These perinatal insults cause a self-perpetuating cascade of peripheral and cerebral inflammation that plays a critical role in the etiology of diffuse white and grey matter injuries that underlies a spectrum of connectivity deficits in survivors from extremely preterm birth. This review focuses on chorioamnionitis and hypoxia-ischemia, which are two important antenatal risk factors for preterm brain injury, and highlights the latest insights on its pathophysiology, potential treatment, and future perspectives to narrow the translational gap between preclinical research and clinical applications.

[Changes of serum interleukin-33 in preterm infants with bronchopulmonary dysplasia]

OBJECTIVE

To study the role of interleukin-33 (IL-33) in the development and progression of bronchopulmonary dysplasia (BPD) in preterm infants.

METHODS

A prospective cohort study was performed on 128 preterm infants with a gestational age of ≤32 weeks and/or a birth weight of ≤1 500 g. They were classified to a non-BPD group with 50 infants, a mild BPD group with 32 infants, a moderate BPD group with 30 infants, and a severe BPD group with 16 infants. Related data were collected, including antepartum factors of mothers (antepartum hormone and chorioamnionitis), intrapartum factors of preterm infants (sex, gestational age, birth weight, mode of birth, and birth asphyxia), treatment after birth (pulmonary surfactant, duration of invasive ventilation, duration of noninvasive ventilation, duration of parenteral nutrition, and length of hospital stay). The high-risk factors for BPD were analyzed. ELISA was used to measure the serum level of IL-33 in preterm infants on days 1, 14, and 28 after birth. The serum level of IL-33 was compared between groups at different time points after birth. The preterm infants with moderate or severe BPD were treated with conventional corticosteroid therapy (DART regimen), and the serum level of IL-33 was measured before and after treatment.

RESULTS

There were significant differences between the preterm infants with BPD and those without BPD in the incidence of maternal chorioamnionitis, gestational age, birth weight, the incidence of birth asphyxia, duration of invasive ventilation, duration of noninvasive ventilation, duration of parenteral nutrition, and total length of hospital stay (P<0.05). There were significant differences in the above indices among the preterm infants with different severities of BPD (P<0.05). On days 1, 14, and 28 after birth, the infants with BPD had a significantly higher serum level of IL-33 than those without BPD, and the serum level of IL-33 tended to increase with the severity of BPD and over the time after birth (P<0.05). The preterm infants with moderate or severe BPD had a significant reduction in the serum level of IL-33 after the treatment with DART regimen (P<0.05).

CONCLUSIONS

Serum IL-33 is closely associated with the development and severity of BPD. Anti-inflammatory therapy with DART regimen can decrease the serum level of IL-33.

Timing of postnatal steroids for bronchopulmonary dysplasia: association with pulmonary and neurodevelopmental outcomes

OBJECTIVE

To determine the associations between age at first postnatal corticosteroids (PNS) exposure and risk for severe bronchopulmonary dysplasia (BPD) and neurodevelopmental impairment (NDI).

STUDY DESIGN

Cohort study of 951 infants born <27 weeks gestational age at NICHD Neonatal Research Network sites who received PNS between 8 days of life (DOL) and 36 weeks' postmenstrual age was used to produce adjusted odds ratios (aOR).

RESULTS

Compared with infants in the reference group (22-28 DOL-lowest rate), aOR for severe BPD was similar for children given PNS between DOL 8 and 49 but higher among infants treated at DOL 50-63 (aOR 1.77, 95% CI 1.03-3.06), and at DOL ≥64 (aOR 3.06, 95% CI 1.44-6.48). The aOR for NDI did not vary significantly by age of PNS exposure.

CONCLUSION

For infants at high risk of BPD, initial PNS should be considered prior to 50 DOL for the lowest associated odds of severe BPD.

Hydrocortisone and bronchopulmonary dysplasia: variables associated with response in premature infants

OBJECTIVE

The primary objective was to evaluate hydrocortisone's efficacy for decreasing respiratory support in premature infants with developing bronchopulmonary dysplasia (BPD). Secondary objectives included assessment of the impact of intrauterine growth restriction (IUGR), maternal history of chorioamnionitis, side effects and route of administration associated with hydrocortisone's efficacy. Dexamethasone as second-line treatment to decrease respiratory support was reviewed.

METHODS

Retrospective chart review of preterm infants requiring respiratory support receiving hydrocortisone.

RESULTS

A total of 48 patients were included. Successful extubation was achieved in 50% of intubated patients after hydrocortisone treatment with no major complications. In our small study, history of maternal chorioamnionitis, IUGR or route of administration did not affect the response. Rescue dexamethasone after hydrocortisone therapy was ineffective in the ten patients who failed extubation following hydrocortisone.

CONCLUSION

Hydrocortisone is effective in decreasing respiratory support in patients with developing BPD without major complications. Randomized studies are warranted to confirm our findings.

The Impact of Postnatal Systemic Steroids on the Growth of Preterm Infants: A Multicenter Cohort Study

Postnatal steroids, often used to prevent and treat bronchopulmonary dysplasia, may influence the growth of preterm infants, although data are scarce in the literature. This is a multicenter cohort study including surviving preterm infants <32 weeks at birth (n = 17,621) from the Spanish Neonatal Network SEN1500 database, without major congenital malformations. Linear regression models were adjusted for postnatal steroids, respiratory severity course (invasive mechanical ventilation at 28 days), progression to moderate–severe bronchopulmonary dysplasia (O₂ at 36 weeks), length of stay, sex, gestational age and z-scores at birth. A subgroup analysis depending on the timing of administration, ventilation status at 28 days and moderate–severe BPD diagnosis was also performed. Overall, systemic postnatal steroids were not independently associated with poorer weight gain (0.1; 95% CI: −0.05 to 0.2 g/kg/day), linear growth (0; 95% CI: −0.03 to 0.01 cm/week) or head circumference growth (−0.01; 95% CI: −0.02 to 0 cm/week). Patients who received steroids after 28 days or who were not O₂ dependent at 36 weeks after having received steroids gained more weight (0.22; 95% CI: 0.04 to 0.4 and 0.2; 95% CI: 0.004 to 0.5 g/kg/day, respectively). Globally, systemic postnatal steroids had no significant adjusted effect on postnatal growth.

A Novel Diagnostic Marker for the Severity of Bronchopulmonary Dysplasia in Very Low Birth Weight Infants: Interleukin-33

Background: Bronchopulmonary dysplasia (BPD) is an important clinical problem for premature infants. Previously, some biomarkers associated with severity of BPD have been studied. In our study, we aimed to investigate the value of interleukin-33 (IL-33) levels as a new biomarker in the follow-up of BPD severity and response to treatment. Materials and Methods: Premature infants of <32 weeks of gestational age and birth weight <1,500 g were included in the study. Infants with BPD were divided into moderate and severe BPD groups. Infants without BPD were assigned as the control group. Cord blood samples were taken from both groups immediately after birth. In addition, blood samples were obtained at the time of diagnosis of BPD and after the end of hydrocortisone (HC) treatment to measure IL-33 values in the serum. Results: During the study period, a total of 192 infants were eligible: 96 infants in the BPD group and 96 in the control group. Cord IL-33 values were similar between control (1.29 ± 0.68 pg/mL) and BPD (moderate/severe) (1.31 ± 0.84 pg/mL) groups (P = 0.813). The levels of IL-33 were higher in BPD group (3.43 ± 0.98 pg/mL) than in the control group (0.98 ± 0.51 pg/mL) (P < 0.001). IL-33 values decreased significantly after HC treatment (pretreatment: 3.43 ± 0.98 pg/mL versus post-treatment: 2.97 ± 0.28 pg/mL) (P < 0.001). In addition, IL-33 levels were significantly higher in severe BPD (3.91 ± 1.22 pg/mL) than in moderate BPD (2.82 ± 0.74) group (P < 0.001). Conclusions: Although the IL-33 level was not predictive of the development of BPD immediately after birth, it may be used as a new biomarker to diagnose, monitor, and follow the response to treatment of BPD.

Is Endocan a Novel Diagnostic Marker for the Severity of Bronchopulmonary Dysplasia in Very Low Birth Weight Infants?

INTRODUCTION

Endocan levels were found to be associated with severity and mortality of the respiratory system diseases.

OBJECTIVE

We aimed to figure out whether endocan was an important marker for the diagnosis, severity and follow-up of bronchopulmonary dysplasia (BPD).

MATERIALS AND METHODS

Infants with moderate/severe BPD, and who required hydrocortisone treatment were included in the study group. Infants without BPD were allocated in the control group. Endocan levels were compared between the control group and the study group, and before and after the treatment in the study group.

RESULTS

A total of 148 infants, 74 infants in the control group and 74 infants in the BPD group, were included. The endocan level was higher in the BPD group than in the control group (P = .001). Endocan levels before treatment in the BPD group was found to be higher than endocan level after treatment (P = .021).

CONCLUSION

Our study found that endocan levels increased in moderate/severe BPD. Serum endocan levels may be a safe and novel indicator for the follow-up of response to treatment and the prognosis of the severity of the disease.

Efficacy and safety of systemic hydrocortisone for the prevention of bronchopulmonary dysplasia in preterm infants: a systematic review and meta-analysis

Early lung inflammation has been implicated in the pathogenesis of bronchopulmonary dysplasia (BPD). We aimed to establish the efficacy and safety of systemic hydrocortisone for the prevention of BPD. A systematic review and meta-analysis were undertaken, with a detailed electronic literature search. Trials involving preterm infants were included if they were randomised to receive systemic hydrocortisone or a placebo. The primary outcome was the composite of survival without BPD at 36-week postmenstrual age (PMA). Results are presented as relative risk (RR) or risk difference (RD) with 95% confidence intervals (CIs), along with numbers needed to treat (NNT) or harm (NNH). After filtering, 12 studies using early (within 1 week of birth) and two using late hydrocortisone were identified. Early systemic hydrocortisone significantly increased the chances of survival without BPD (RR 1.13, 95% CI [1.01, 1.26], NNT 18), and survival without moderate-to-severe neurodevelopmental impairment (1.13 [1.02, 1.26], NNT 14). Infants who received hydrocortisone had a higher risk of intestinal perforation (1.69 [1.07, 2.68], NNH 30), primarily with concurrent treatment for patent ductus arteriosus.Conclusion: Early systemic hydrocortisone is a modestly effective therapy for the prevention of BPD in preterm infants, although some safety concerns remain. No conclusions could be drawn for late hydrocortisone due to the paucity of studies. What is Known: • Preterm infants are at high risk of developing bronchopulmonary dysplasia (BPD) and early lung inflammation plays a significant role in its pathogenesis. • Both early and late systemic dexamethasone seems to reduce the incidence of BPD, but its use is associated with serious neurodevelopmental impairment at follow-up. What is New: • Early systemic hydrocortisone significantly improved survival without BPD at 36 weeks and survival without moderate to severe neurodevelopmental impairment on follow up. • Incidence of gastrointestinal perforation associated with concurrent treatment for PDA was significantly higher, although early systemic hydrocortisone reduced the need for treatment of PDAs.

Preterm brain Injury: White matter injury

Despite the advances in neonatal intensive care, the preterm brain remains vulnerable to white matter injury (WMI) and disruption of normal brain development (i.e., dysmaturation). Compared to severe cystic WMI encountered in the past decades, contemporary cohorts of preterm neonates experience milder WMIs. More than destructive lesions, disruption of the normal developmental trajectory of cellular elements of the white and the gray matter occurs. In the acute phase, in response to hypoxia-ischemia and/or infection and inflammation, multifocal areas of necrosis within the periventricular white matter involve all cellular elements. Later, chronic WMI is characterized by diffuse WMI with aberrant regeneration of oligodendrocytes, which fail to mature to myelinating oligodendrocytes, leading to myelination disturbances. Complete neuronal degeneration classically accompanies necrotic white matter lesions, while altered neurogenesis, represented by a reduction of the dendritic arbor and synapse formation, is observed in response to diffuse WMI. Neuroimaging studies now provide more insight in assessing both injury and dysmaturation of both gray and white matter. Preterm brain injury remains an important cause of neurodevelopmental disabilities, which are still observed in up to 50% of the preterm survivors and take the form of a complex combination of motor, cognitive, and behavioral concerns.

Dose response effects of postnatal hydrocortisone on growth and growth factors in the neonatal rat

BACKGROUND AND PURPOSE

Hydrocortisone (HC), at different dosages, is used in critically ill newborns for lung stability, blood pressure support, and prevention of chronic lung disease (CLD). Its long-term effects on postnatal growth are not well studied. We hypothesized that early exposure to high doses of HC adversely affects growth, growth factors, metabolic hormones, and neurological outcomes, persisting in adulthood.

EXPERIMENTAL DESIGN

Rat pups received a single daily intramuscular dose of HC (1 mg/kg/day, 5 mg/kg/day, or 10 mg/kg/day on days 3, 4 & 5 postnatal age (P3, P4, P5). Age-matched controls received equivalent volume saline. Body weight, linear growth, and neurological outcomes were monitored. Animals were sacrificed at P21, P45, and P70 for blood glucose, insulin, IGF-I, GH, leptin, and corticosterone levels. Liver mRNA expression of IGFs and IGFBPs were determined at P21 and P70. Memory and learning abilities were tested using the Morris water maze test at P70.

RESULTS

HC suppressed body weight and length at P12, P21 and P45, but by P70 there was catchup overgrowth in the 5 and 10 mg/kg/day groups. At P70 blood insulin, IGF-I, GH, and leptin levels were low, whereas blood glucose, and liver IGFs and IGFBPs were high in the high dose groups. High HC also caused delayed memory and learning abilities at P70.

CONCLUSIONS

These data demonstrate that while higher doses of HC may be required for hemodynamic stability and prevention of CLD, these doses may result in growth deficits, as well as neurological and metabolic sequelae in adulthood.

Recent advances in preclinical and clinical multimodal MR in the newborn brain

Aside from injury identification, MRI of the newborn brain has given us insight into cortical and white matter development, identified windows of vulnerabilities, enabled the introduction of therapeutic hypothermia which has become the standard of care in neonatal asphyxia, and is fostering leapfrogging discoveries in the field of neuro-genetics. This article reviews the main advances in recent years in newborn brain imaging both in preclinical and clinical research.

Use of Glucocorticoids for the Fetus and Preterm Infant

The soon-to-be-delivered fetus and preterm infant have been treated with glucocorticoids to prepare for postnatal life, historically for more than 40 years. The use of glucocorticoids is as much for replacement of cortisol in the setting of a poorly functioning hypothalamic-pituitary-adrenal axis in the preterm infant, as it is for prevention of long-term lung dysfunction. Potential negative effects of glucocorticoid treatment on brain development and function have been observed more often with dexamethasone therapy than with use of other glucocorticoids. Overall, glucocorticoid treatment has improved the outcome of the preterm infant.

Corticotrophin-releasing hormone stimulation tests for the infants with relative adrenal insufficiency

BACKGROUND

Very low birthweight (VLBW) infants are considered to be vulnerable to relative adrenal insufficiency (RAI); however, diagnosis is difficult in some clinical settings. Considering this background, it is necessary to establish a diagnosis of RAI in preterm infants.

OBJECTIVE

In this study, we attempted to clarify the difference in response to CRH stimulation tests for preterm infants with or without RAI.

METHODS

Between June 2009 and December 2015, we performed CRH stimulation tests for preterm infants born at a gestational age of <30 weeks at around 2 weeks of age. Retrospectively, subjects were classified into two groups: infants with RAI (n = 9) or without RAI (n = 17) based on the clinical symptoms and responsiveness to hydrocortisone.

RESULTS

We found no difference in base or peak serum cortisol levels related to CRH stimulation tests between the two groups; however, delta cortisol levels and responsive ratio (peak-to-base ratio) were significantly reduced in infants with RAI. 140 nmol/L for delta cortisol or 1.5 times for peak-to-base ratio may be cut-off levels in preterm infants.

CONCLUSION

This study provides evidence that base cortisol levels of preterm infants with RAI were not different from those without RAI; however, CRH stimulation tests may be a useful tool for the diagnosis of RAI in preterm infants.

Long-term postnatal steroid effect in very low birth weight infants

We examined whether hydrocortisone exposure≤1week in very low birth weight infants (VLBWI) was associated with poor neurodevelopmental outcomes at corrected 18months. Further, the clinical factors associated with worse long term outcome were also evaluated. Of a total of 191 VLBWI, the clinical data for these infants relating were retrospectively collected for analysis. Among the 191 VLBWI, 115 (60.2%) infants were exposed to early postnatal hydrocortisone≤1week of life in our NICU of Seoul St. Mary's Hospital, The Catholic University of Korea between December 2012 and December 2014. The morbidities were significantly higher in the group with early hydrocortisone exposure group. At corrected age of 18months, 109/183 (59.6%) infants in the early hydrocortisone exposure group had significantly lower scores in all three (cognitive, language and motor) composites of Bayley Scales of Infant and Toddler Development III. The multivariable logistic regression analysis showed that only periventricular leukomalacia (PVL) is consistently associated with poor long-term outcomes. Our results suggest that early hydrocortisone exposure≤1week in VLBWI may not increase the risk for poor long-term outcomes compared to those not exposed. Only PVL is considered as a risk factor for poor long-term neurodevelopmental outcomes.

Systemic Corticosteroids for the Prevention of Bronchopulmonary Dysplasia: Picking the Right Drug for the Right Baby

Bronchopulmonary dysplasia is a morbidity of prematurity with implications into adulthood on respiratory and neurologic health. Multiple risk factors contribute to the development of bronchopulmonary dysplasia leading to examination of various strategies of prevention. Systemic corticosteroids are one prevention strategy with a large body of data, creating an ongoing controversy regarding the risks and benefits of therapy. Careful consideration of the available data along with the clinical characteristics of the individual infant is required before using this powerful therapy.

Managing Children with Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia is one of the most significant early childhood chronic respiratory diseases. The article features modern approaches to preventing, diagnosing and treating broncho-pulmonary dysplasia, as well as ways of preventing complications and undesirable disease outcomes in patients older than 3 years. Members of professional associations — Union of Pediatricians of Russia and Russian Association of Perinatal Medicine Specialists — have summarized the experience of managing this category of patients at leading Russian pediatric centers according to the principles of evidence-based medicine and have provided scientific and practical data corresponding to the world level of knowledge with regard to the present problem.

Hydrocortisone use in ventilated extremely preterm infants decreased bronchopulmonary dysplasia with no effects on neurodevelopment after two years

AIM

We assessed the outcomes of ventilated extremely premature infants treated with late postnatal corticosteroids from 2005-2008, according to permissive or restrictive policies in two centres.

METHODS

This retrospective study included inborn infants below 27 weeks of gestational age who were ventilator dependent after 14 days. Centre P permitted postnatal corticosteroids but centre R restricted their use. The effects on infants were assessed in hospital and after two years using multivariable analysis.

RESULTS

We compared 62 infants from centre P, including 92% who received hydrocortisone, and 48 infants from centre R, including 13% who received betamethasone. Infants from both centres had comparable baseline characteristics and perinatal management, but bronchopulmonary dysplasia (BPD) rates were significantly lower in centre P (30% versus 71%, p < 0.001) and this centre was significantly associated with a younger post-conceptional age at oxygen weaning, with an adjusted hazard ratio (aHR) of 0.45 and an aHR of 0.51at discharge. At two years of corrected age, 18% of centre P infants and 30% of centre R infants showed poor neurodevelopmental outcome (p = 0.18).

CONCLUSION

Using hydrocortisone after 14 days on ventilated extremely preterm infants was associated with decreased BPD, with no apparent effects on neurodevelopment at two years of corrected age.

Learning Disabilities in Extremely Low Birth Weight Children and Neurodevelopmental Profiles at Preschool Age

At school age extremely low birth weight (ELBW) and extremely low gestational age (ELGAN) children are more likely to show Learning Disabilities (LDs) and difficulties in emotional regulation. The aim of this study was to investigate the incidence of LDs at school age and to detect neurodevelopmental indicators of risk for LDs at preschool ages in a cohort of ELBW/ELGAN children with broadly average intelligence. All consecutively newborns 2001-2006 admitted to the same Institution entered the study. Inclusion criteria were BW < 1000 g and/or GA < 28 weeks. Exclusion criteria were severe cerebral injuries, neurosensory disabilities, genetic abnormalities, and/or a Developmental Quotient below normal limits (< 1 SD) at 6 years. The presence of learning disabilities at school age was investigated through a parent-report questionnaire at children's age range 9-10 years. Neurodevelopmental profiles were assessed through the Griffiths Mental Development Scales at 1 and 2 years of corrected age and at 3, 4, 5, and 6 years of chronological age and were analyzed comparing two groups of children: those with LDs and those without. At school age 24 on 102 (23.5%) of our ELBW/ELGAN children met criteria for LDs in one or more areas, with 70.8% comorbidity with emotional/attention difficulties. Children with LDs scored significantly lower in the Griffiths Locomotor and Language subscales at 2 years of corrected age and in the Personal-social, Performance and Practical Reasoning subscales at 5 years of chronological age. Our findings suggest that, among the early developmental indicators of adverse school outcome, there is a poor motor experimentation, language delay, and personal-social immaturity. Cognitive rigidity and poor ability to manage practical situations also affect academic attainment. Timely detection of these early indicators of risk is crucial to assist the transition to school.

Effect of early low-dose hydrocortisone on survival without bronchopulmonary dysplasia in extremely preterm infants (PREMILOC): a double-blind, placebo-controlled, multicentre, randomised trial

BACKGROUND

Bronchopulmonary dysplasia, a major complication of extreme prematurity, has few treatment options. Postnatal steroid use is controversial, but low-dose hydrocortisone might prevent the harmful effects of inflammation on the developing lung. In this study, we aimed to assess whether low-dose hydrocortisone improved survival without bronchopulmonary dysplasia in extremely preterm infants.

METHODS

In this double-blind, placebo-controlled, randomised trial done at 21 French tertiary-care neonatal intensive care units (NICUs), we randomly assigned (1:1), via a secure study website, extremely preterm infants inborn (born in a maternity ward at the same site as the NICU) at less than 28 weeks of gestation to receive either intravenous low-dose hydrocortisone or placebo during the first 10 postnatal days. Infants randomly assigned to the hydrocortisone group received 1 mg/kg of hydrocortisone hemisuccinate per day divided into two doses per day for 7 days, followed by one dose of 0·5 mg/kg per day for 3 days. Randomisation was stratified by gestational age and all infants were enrolled by 24 h after birth. Study investigators, parents, and patients were masked to treatment allocation. The primary outcome was survival without bronchopulmonary dysplasia at 36 weeks of postmenstrual age. We used a sequential analytical design, based on intention to treat, to avoid prolonging the trial after either efficacy or futility had been established. This trial is registered with ClinicalTrial.gov, number NCT00623740.

FINDINGS

1072 neonates were screened between May 25, 2008, and Jan 31, 2014, of which 523 were randomly assigned (256 hydrocortisone, 267 placebo). 255 infants on hydrocortisone and 266 on placebo were included in analyses after parents withdrew consent for one child in each group. Of the 255 infants assigned to hydrocortisone, 153 (60%) survived without bronchopulmonary dysplasia, compared with 136 (51%) of 266 infants assigned to placebo (odds ratio [OR] adjusted for gestational age group and interim analyses 1·48, 95% CI 1·02-2·16, p=0·04). The number of patients needed to treat to gain one bronchopulmonary dysplasia-free survival was 12 (95% CI 6-200). Sepsis rate was not significantly different in the study population as a whole, but subgroup analyses showed a higher rate only in infants born at 24-25 weeks gestational age who were treated with hydrocortisone (30 [40%] of 83 vs 21 [23%] of 90 infants; sub-hazard ratio 1·87, 95% CI 1·09-3·21, p=0·02). Other potential adverse events, including notably gastrointestinal perforation, did not differ significantly between groups.

INTERPRETATION

In extremely preterm infants, the rate of survival without bronchopulmonary dysplasia at 36 weeks of postmenstrual age was significantly increased by prophylactic low-dose hydrocortisone. This strategy, based on a physiological rationale, could lead to substantial improvements in the management of the most premature neonates.

FUNDING

Assistance Publique-Hôpitaux de Paris.

Patent Ductus Arteriosus and Brain Volume

BACKGROUND AND OBJECTIVES

A hemodynamically significant patent ductus arteriosus (PDA) can compromise perfusion and oxygenation of the preterm brain. Reports suggest that PDA is associated with increased mortality and morbidity. We hypothesize that long-standing low cerebral oxygenation due to PDA might affect brain volume at term equivalent age.

METHODS

Observational study in 140 infants investigating the relationship between near-infrared spectroscopy-monitored cerebral oxygen saturation (rSco2) and MRI-assessed regional brain volume and maturation of the posterior limb of the internal capsule at term-equivalent age in 3 groups: those whose PDA closed with indomethacin, those who needed additional surgical closure, and matched controls.

RESULTS

The surgery group had the lowest rSco2 values before closure (n = 35), 48% ± 9.7% (mean ± SD) as compared with the indomethacin (n = 35), 59% ± 10.4 (P < .001), and control groups (n = 70), 66% ± 6.9 (P < .001); the highest postnatal age before effective treatment; and the lowest volumes of most brain regions at term-equivalent age. Multiple linear regression analysis showed a significant effect of preductal closure rSco2 on cerebellar volume in this group. No differences were found in maturation of the posterior limb of the internal capsule.

CONCLUSIONS

Long-standing suboptimal cerebral oxygenation due to a PDA may negatively influence brain growth, affecting neurodevelopmental outcome.

Effects of Posthemorrhagic Ventricular Dilatation in the Preterm Infant on Brain Volumes and White Matter Diffusion Variables at Term-Equivalent Age

OBJECTIVE

To evaluate the differential impact of germinal matrix-intraventricular hemorrhage (GMH-IVH) and posthemorrhagic ventricular dilatation (PHVD) on brain and cerebrospinal fluid (CSF) volumes and diffusion variables in preterm born infants at term-equivalent age (TEA).

STUDY DESIGN

Nineteen infants (gestational age <31 weeks) with GMH-IVH grade II-III according to Papile et al and subsequent PHVD requiring intervention were matched against 19 controls with GMH-IVH grade II but no PHVD and 19 controls without GMH-IVH. Outcome variables on magnetic resonance imaging (MRI) including diffusion weighted imaging at TEA were volumes of white matter, cortical gray matter, deep gray matter, brainstem, cerebellum, ventricles, extracerebral CSF, total brain tissue, and intracranial volume (ICV), as well as white matter and cerebellar apparent diffusion coefficients (ADCs). Effects of GMH-IVH and PHVD on TEA-MRI measurements were evaluated using multivariable regression analysis. Brain and CSF volumes were adjusted for ICV to account for differences in bodyweight at TEA-MRI and ICV between cases and controls.

RESULTS

PHVD was independently associated with volumes of deep gray matter (β [95% CI]: -1.4 cc [-2.3; -.5]), cerebellum (-2.7 cc [-3.8; -1.6]), ventricles (+12.7 cc [7.9; 17.4]), and extracerebral CSF (-11.2 cc [-19.2; -3.3]), and with ADC values in occipital, parieto-occipital, and parietal white matter (β: +.066-.119×10(-3) mm(2)/s) on TEA-MRI (P < .05). No associations were found between GMH-IVH grade II-III and brain and CSF volumes or ADC values at TEA.

CONCLUSIONS

PHVD was negatively related to deep gray matter and cerebellar volumes and positively to white matter ADC values on TEA-MRI, despite early intervention for PHVD in the majority of the infants. These relationships were not observed for GMH-IVH.

Controversies in preterm brain injury

In this review, we highlight critical unresolved questions in the etiology and mechanisms causing preterm brain injury. Involvement of neurons, glia, endogenous factors and exogenous exposures is considered. The structural and functional correlates of interrupted development and injury in the premature brain are under active investigation, with the hope that the cellular and molecular mechanisms underlying developmental abnormalities in the human preterm brain can be understood, prevented or repaired.

Outcomes for extremely premature infants

Premature birth is a significant cause of infant and child morbidity and mortality. In the United States, the premature birth rate, which had steadily increased during the 1990s and early 2000s, has decreased annually for 7 years and is now approximately 11.39%. Human viability, defined as gestational age at which the chance of survival is 50%, is currently approximately 23 to 24 weeks in developed countries. Infant girls, on average, have better outcomes than infant boys. A relatively uncomplicated course in the intensive care nursery for an extremely premature infant results in a discharge date close to the prenatal estimated date of confinement. Despite technological advances and efforts of child health experts during the last generation, the extremely premature infant (less than 28 weeks gestation) and extremely low birth weight infant (<1000 g) remain at high risk for death and disability with 30% to 50% mortality and, in survivors, at least 20% to 50% risk of morbidity. The introduction of continuous positive airway pressure, mechanical ventilation, and exogenous surfactant increased survival and spurred the development of neonatal intensive care in the 1970s through the early 1990s. Routine administration of antenatal steroids during premature labor improved neonatal mortality and morbidity in the late 1990s. The recognition that chronic postnatal administration of steroids to infants should be avoided may have improved outcomes in the early 2000s. Evidence from recent trials attempting to define the appropriate target for oxygen saturation in preterm infants suggests arterial oxygen saturation between 91% and 95% (compared with 85%-89%) avoids excess mortality; however, final analyses of data from these trials have not been published, so definitive recommendations are still pending. The development of neonatal neurocritical intensive care units may improve neurocognitive outcomes in this high-risk group. Long-term follow-up to detect and address developmental, learning, behavioral, and social problems is critical for children born at these early gestational ages.The striking similarities in response to extreme prematurity in the lung and brain imply that agents and techniques that benefit one organ are likely to also benefit the other. Finally, because therapy and supportive care continue to change, the outcomes of extremely low birth weight infants are ever evolving. Efforts to minimize injury, preserve growth, and identify interventions focused on antioxidant and anti-inflammatory pathways are now being evaluated. Thus, treating and preventing long-term deficits must be developed in the context of a "moving target."

Bronchopulmonary dysplasia is associated with delayed structural brain maturation in preterm infants

BACKGROUND

In recent years, cerebral magnetic resonance imaging (MRI) has been increasingly used to depict the wide spectrum of preterm brain injury. Furthermore, it has already been demonstrated by MRI at term-equivalent age (TEA) that preterm infants show delayed brain maturation as compared to term infants, and this delay has been related to neurobehavioral outcome.

OBJECTIVES

The aim of the current study was to investigate the influence of prevalent neonatal risk factors for adverse outcome on structural brain maturation in very preterm infants at TEA.

METHODS

One hundred and thirty very preterm infants born at a mean gestational age of 29.7 weeks were included. MRI was performed at TEA and given a validated 'total maturation score'. Brain maturation scores were compared with neonatal data.

RESULTS

In univariate analysis, bronchopulmonary dysplasia (BPD), late-onset sepsis and retinopathy of prematurity were significantly associated with delayed brain maturation. Furthermore, infants with delayed maturation had been ventilated significantly longer and more often suffered from severe arterial hypotension. In multivariate analysis, BPD remained significant as predictor of delayed brain maturation.

CONCLUSIONS

This study is the first to show that delayed structural brain maturation as evaluated by MRI at TEA is preceded by BPD, which is known to be a predictor of adverse outcome in preterm infants. This finding adds further evidence to show that adverse outcome in preterm infants may have additional neural correlates that exceed common brain injury.

Review of the antenatal and postnatal use of steroids

Antenatal and postnatal corticosteroids play an extremely important role in the management of premature infants. The antenatal administration of steroids has been universally implemented. They have not only been shown to reduce the incidence and severity of respiratory distress syndrome (RDS), but also have an impact on the incidence of intraventricular hemorrhage (IVH), patent ductus arteriosus (PDA), necrotizing enterocolitis (NEC), and possibly retinopathy of prematurity (ROP) by reducing the need for supplemental oxygen due to improved lung function. The postnatal use of dexamethasone in ventilated infants has been adopted with caution, as there have been several reports of long-term neurodevelopmental complications with this therapy. Hence, changes in dosage and indications and the search for alternative therapies has emerged. Hydrocortisone appears to be a good alternative, with reassuring long-term evaluations thus far.

Association between postnatal dexamethasone for treatment of bronchopulmonary dysplasia and brain volumes at adolescence in infants born very preterm

OBJECTIVES

To compare brain volumes in adolescents who were born extremely preterm (<28 weeks gestation) who had received postnatal dexamethasone, and to determine if there was a postnatal dexamethasone dose-response effect on brain volumes.

STUDY DESIGN

Geographical cohort study of extremely preterm adolescents born in 1991-1992 in Victoria, Australia. T1-weighted magnetic resonance imaging was performed at 18 years of age. Segmented and parcellated brain volumes were calculated using an automated segmentation method (FreeSurfer) and compared between groups, with and without adjustment for potential confounders. The relationships between total postnatal dexamethasone dose and brain volumes were explored using linear regression.

RESULTS

Of the 148 extremely preterm participants, 55 (37%) had received postnatal dexamethasone, with a cumulative mean dose of 7.7 mg/kg. Compared with participants who did not receive postnatal dexamethasone, those who did had smaller total brain tissue volumes (mean difference -3.6%, 95% CI [-7.0%, -0.3%], P value = .04) and smaller white matter, thalami, and basal ganglia volumes (all P < .05). There was a trend of smaller total brain and white matter volumes with increasing dose of postnatal dexamethasone (regression coefficient -7.7 [95% CI -16.2, 0.8] and -3.2 [-6.6, 0.2], respectively).

CONCLUSIONS

Extremely preterm adolescents who received postnatal dexamethasone in the newborn period had smaller total brain tissue volumes than those who did not receive postnatal dexamethasone, particularly white matter, thalami, and basal ganglia. Vulnerability of brain tissues or structures associated with postnatal dexamethasone varies by structure and persists into adolescence.

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.

Unmyelinated white matter loss in the preterm brain is associated with early increased levels of end-tidal carbon monoxide

Objective

Increased levels of end-tidal carbon monoxide (ETCOc) in preterm infants during the first day of life are associated with oxidative stress, inflammatory processes and adverse neurodevelopmental outcome at 2 years of age. Therefore, we hypothesized that early ETCOc levels may also be associated with impaired growth of unmyelinated cerebral white matter.

Methods

From a cohort of 156 extremely and very preterm infants in which ETCOc was determined within 24 h after birth, in 36 infants 3D-MRI was performed at term-equivalent age to assess cerebral tissue volumes of important brain regions.

Results

Linear regression analysis between cerebral ventricular volume, unmyelinated white matter/total brain volume-, and cortical grey matter/total brain volume-ratio and ETCOc showed a positive, negative and positive correlation, respectively. Multivariable analyses showed that solely ETCOc was positively related to cerebral ventricular volume and cortical grey matter/total brain volume ratio, and that solely ETCOc was inversely related to the unmyelinated white matter/total brain volume ratio, suggesting that increased levels of ETCOc, associated with oxidative stress and inflammation, were related with impaired growth of unmyelinated white matter.

Conclusion

Increased values of ETCOc, measured within the first 24 hours of life may be indicative of oxidative stress and inflammation in the immediate perinatal period, resulting in impaired growth of the vulnerable unmyelinated white matter of the preterm brain.

Steroids and injury to the developing brain: net harm or net benefit?

Deleterious effects result from both glucocorticoid insufficiency and excess glucocorticoid tissue exposure in the developing brain. Accumulating evidence suggests a net benefit of postnatal glucocorticoid therapy when administered shortly after the first week of life to premature infants with early and persistent pulmonary dysfunction, particularly in those with evidence of relative adrenal insufficiency. The decision to treat with steroids should ensure maximum respiratory benefit at the lowest possible neurologic risk, while avoiding serious systemic complications. Ongoing clinical trials must validate this approach.

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.