Hydrocortisone to Improve Survival without Bronchopulmonary Dysplasia

Postnatal corticosteroid therapy in bronchopulmonary dysplasia - why animal studies disagree with clinical trials?

The systematic review and meta-analysis of newborn animal models by Irene Lok et al. is the first to extensively summarize the literature regarding postnatal systemic corticosteroid use on lung development of newborn rodent models. The meta-analysis showed that the use of postnatal corticosteroids resulted in a reduction in body weight along with persistent alveolar simplification. The most frequently used corticosteroid was dexamethasone. Corticosteroids have been extensively used in clinical trials in preterm newborns. Trials using early systemic administration of corticosteroids reduced the rate of BPD or mortality with no increase in the rates of cerebral palsy. Use of late systemic corticosteroids (administered >7 days after birth) also reduced the rate of BPD, mortality, and combined outcome of mortality or BPD. Late systemic corticosteroids showed no impact on the rates of neurodevelopmental outcomes in later childhood. It is important to note that later stages of inflammation leading to a more severe form of BPD continues to be a problem with no clear therapy in sight. The authors made a critical point in their paper - the negative effects of steroids were greater in the normal lung control animals than in the injured. This conveys caution in using steroids in a prophylactic manner. IMPACT: Use of systemic corticosteroids in clinical trials have shown good response in preterm neonates evidenced by reduced rate of bronchopulmonary dysplasia. Rodent models have not shown a similar beneficial response. Use of systemic corticosteroids have caused greater arrest of lung development in rodent models with normal lungs compared to those with lung damage.

Azithromycin therapy for prevention of chronic lung disease of prematurity (AZTEC): a multicentre, double-blind, randomised, placebo-controlled trial

BACKGROUND

Systematic reviews have reported conflicting evidence on whether macrolide antibiotics reduce rates of chronic lung disease of prematurity (CLD) in at-risk preterm infants born at less than 30 weeks' gestation, including in those colonised with pulmonary Ureaplasma spp. Since an adequately powered trial has been lacking, we aimed to assess if the macrolide azithromycin improved survival without the development of physiologically defined moderate or severe CLD in preterm infants.

METHODS

AZTEC was a multicentre, double-blind, randomised, placebo-controlled trial conducted in 28 tertiary neonatal intensive care units in the UK. Infants were eligible if they were born at less than 30 weeks' gestation and had received at least 2 h of either non-invasive (continuous positive airway pressure or humidified high flow nasal cannula therapy) or invasive respiratory support (via endotracheal tube) within 72 h of birth. Eligible infants were randomly allocated in a 1:1 ratio using random permuted blocks of four to receive either intravenous azithromycin at 20 mg/kg per day for 3 days followed by 10 mg/kg for 7 days, or to placebo. Allocation was stratified by centre and gestational age at birth (<28 weeks vs ≥28 weeks). Azithromycin and placebo vials were encased in tamper-evident custom cardboard cartons to ensure masking for clinicians, parents, and the research team. The primary outcome was survival without development of physiologically defined moderate or severe CLD at 36 weeks' postmenstrual age. Outcomes and safety were analysed on an intention-to-treat basis (all randomly allocated infants, regardless of any post-randomisation events). The study was registered with ISRCRN (11650227) and is closed.

FINDINGS

Infants were recruited between Oct 9, 2019, and March 22, 2022. 799 (53·1%) of 1505 eligible infants underwent random allocation; three infants were withdrawn, including consent to use their data, leaving 796 infants for analysis. Survival without moderate or severe CLD occurred in 166 (42%) of 394 infants in the intervention group and 179 (45%) of 402 in the placebo group (three-level adjusted OR [aOR] 0·84, 95% CI 0·55-1·29, p=0·43). Pulmonary Ureaplasma spp colonisation did not influence treatment effect. Overall, seven serious adverse events were reported for the azithromycin group (five graded as severe, two as moderate), and six serious adverse events were reported in the placebo group (two severe, two moderate, and two mild), as assessed by the local principal investigators.

INTERPRETATION

Since prophylactic use of azithromycin did not improve survival without development of physiologically-defined CLD, regardless of Ureaplasma spp colonisation, it cannot be recommended in clinical practice.

FUNDING

UK National Institute for Health and Care Research.

Quercetin alleviates hyperoxia-induced bronchopulmonary dysplasia by inhibiting ferroptosis through the MAPK/PTGS2 pathway: Insights from network pharmacology, molecular docking, and experimental evaluations

Quercetin, a bioactive natural compound renowned for its potent anti-inflammatory, antioxidant, and antiviral properties, has exhibited therapeutic potential in various diseases. Given that bronchopulmonary dysplasia (BPD) development is closely linked to inflammation and oxidative stress, and quercetin, a robust antioxidant known to activate NRF2 and influence the ferroptosis pathway, offers promise for a wide range of age groups. Nonetheless, the specific role of quercetin in BPD remains largely unexplored. This study aims to uncover the target role of quercetin in BPD through a combination of network pharmacology, molecular docking, computer analyses, and experimental evaluations.

Synergistic effects of achieving perinatal interventions on bronchopulmonary dysplasia in preterm infants

To investigate the effect of perinatal interventions on the risk of severe BPD (sBPD) and death in extremely preterm infants (EPIs) and their synergistic effects. This was a secondary analysis of the prospective cohort Chinese Neonatal Network (CHNN). Infants with a birth weight of 500 to 1250 g or 24-28 weeks completed gestational age were recruited. The impacts and the synergistic effects of six evidence-based perinatal interventions on the primary outcomes of sBPD and death were assessed by univariate and multivariable logistic regression modeling. Totally, 6568 EPIs were finally enrolled. Antenatal corticosteroid (adjusted OR, aOR, 0.74; 95%CI, 0.65-083), birth in centers with tertiary NICU (aOR, 0.64; 95%CI, 0.57-0.72), preventing intubation in the delivery room (aOR, 0.65; 95%CI, 0.58-0.73), early caffeine therapy (aOR, 0.59; 95%CI, 0.52-0.66), and early extubating (aOR, 0.42; 95%CI 0.37-0.47), were strongly associated with a lower risk of sBPD and death while early surfactant administration was associated with a lower risk of death (aOR, 0.84; 95%CI, 0.72, 0.98). Compared with achieving 0/1 perinatal interventions, achieving more than one intervention was associated with decreased rates (46.6% in 0/1 groups while 38.5%, 29.6%, 22.2%, 16.2%, and 11.7% in 2/3/4/5/6-intervention groups respectively) and reduced risks of sBPD/death with aORs of 0.76(0.60, 0.96), 0.55(0.43, 0.69), 0.38(0.30, 0.48), 0.28(0.22, 0.36), and 0.20(0.15, 0.27) in 2, 3, 4, 5, and 6 intervention groups respectively. Subgroup analyses showed consistent results.

CONCLUSION

Six perinatal interventions can effectively reduce the risk of sBPD and death in a synergistic form.

WHAT IS KNOWN

• Bronchopulmonary dysplasia (BPD) is a multifactorial chronic lung disease associated with prematurity. The effective management of BPD requires a comprehensive set of interventions. However, the extent to which these interventions can mitigate the risk of severe outcomes, such as severe BPD or mortality, or if they possess synergistic effects remains unknown.

WHAT IS NEW

• The implementation of various perinatal interventions, such as prenatal steroids, birth in centers with tertiary NICU, early non-Invasive respiratory support, surfactant administration within 2 hours after birth, early caffeine initiation within 3 days, and early extubation within 7 days after birth has shown promising results in the prevention of severe bronchopulmonary dysplasia (BPD) or mortality in extremely preterm infants. Moreover, these interventions have demonstrated synergistic effects when implemented in combination.

Prophylactic early low-dose hydrocortisone and survival without bronchopulmonary dysplasia among extremely preterm infants born at 22-27 weeks' gestation

OBJECTIVE

To compare survival without BPD among extremely preterm infants (EPI) who received prophylactic early low-dose hydrocortisone (PEH) with those who did not (non-PEH).

STUDY DESIGN

This single-center retrospective study compared risk-adjusted rates of survival without BPD, BPD, bowel perforation, and late-onset sepsis among infants (22-27 weeks' gestation at birth) who received PEH (n = 82) and who did not (n = 205).

RESULTS

Infants in the PEH group were of lower gestational age, lower birthweight, and higher day-1 risk of death/BPD. After adjusting for risk of death/BPD, PEH-treated infants demonstrated increased survival without BPD (aOR 2.04, 95%CI 1.1-3.7), and lower BPD rates (aOR 0.46, 95%CI 0.25-0.87). Importantly, bowel perforation or sepsis rate were similar among both groups.

CONCLUSION

After risk adjustment, PEH-treated infants demonstrated improved survival without BPD and did not increase rates of bowel perforation or sepsis. In our cohort of infants, PEH was safe and effective among the sickest preterm neonates.

Weaning from mechanical ventilation and assessment of extubation readiness

Tremendous advancements in neonatal respiratory care have contributed to the improved survival of extremely preterm infants (gestational age ≤ 28 weeks). While mechanical ventilation is often considered one of the most important breakthroughs in neonatology, it is also associated with numerous short and long-term complications. For those reasons, clinical research has focused on strategies to avoid or reduce exposure to mechanical ventilation. Nonetheless, in the extreme preterm population, 70-100% of infants born 22-28 weeks of gestation are exposed to mechanical ventilation, with nearly 50% being ventilated for ≥ 3 weeks. As contemporary practices have shifted towards selectively reserving mechanical ventilation for those patients, mechanical ventilation weaning and extubation remain a priority yet offer a heightened challenge for clinicians. In this review, we will summarize the evidence for different strategies to expedite weaning and assess extubation readiness in preterm infants, with a particular focus on extremely preterm infants.

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.

Steroid Metabolomic Signature in Term and Preterm Infants

Adrenal function is essential for survival and well-being of preterm babies. In addition to glucocorticoids, it has been hypothesized that C19-steroids (DHEA-metabolites) from the fetal zone of the adrenal gland may play a role as endogenous neuroprotective steroids. In 39 term-born (≥37 weeks gestational age), 42 preterm (30-36 weeks) and 51 early preterm (<30 weeks) infants 38 steroid metabolites were quantified by GC-MS in 24-h urinary samples. In each gestational age group, three distinctive cluster were identified by pattern analysis (k-means clustering). Individual steroidal fingerprints and clinical phenotype were analyzed at the 3rd day of life. Overall, the excretion rates of C21-steroids (glucocorticoid precursors, cortisol, and cortisone metabolites) were low (<99 μg/kg body weight/d) whereas the excretion rates of C19-steroids were up to 10 times higher. There was a shift to higher excretion rates of C19-steroids in both preterm groups compared to term infants but only minor differences in the distribution of C21-steroids. Comparable metabolic patterns were found between gestational age groups: Cluster 1 showed mild elevation of C21- and C19-steroids with the highest incidence of neonatal morbidities in term and severe intraventricular hemorrhage in early preterm infants. In cluster 2 lowest excretion in general was noted but no clinically unique phenotype. Cluster 3 showed highest elevation of C21-steroids and C19-steroids but no clinically unique phenotype. Significant differences in steroid metabolism between clusters are only partly reflected by gestational age and disease severity. In early preterm infants, higher excretion rates of glucocorticoids and their precursors were associated with severe cerebral hemorrhage. High excretion rates of C19-steroids in preterm infants may indicate a biological significance.

Outcomes of postnatal systemic corticosteroids administration in ventilated preterm newborns: a systematic review of randomized controlled trials

Introduction

Prolonged mechanical ventilation, commonly used to assist preterm newborns, increases the risk of developing bronchopulmonary dysplasia (BPD). In recent decades, studies have demonstrated that systemic corticosteroids play a significant role in the prevention and management of BPD. In this systematic review of randomized controlled trials (RCTs), we evaluated the association between the administration of systemic corticosteroids in preterm infants and its long-term outcomes, such as neurodevelopment, growth, extubation rate, and related adverse effects.

Methods

We conducted an electronic search in Medline, Scopus, and PubMed using the following terms: "premature infants" and "corticosteroids." We considered all RCTs published up to June 2023 as eligible. We included all studies involving preterm newborns treated with systemic corticosteroids and excluded studies on inhaled corticosteroids.

Results

A total of 39 RCTs were evaluated. The influence of steroids administered systemically during the neonatal period on long-term neurological outcomes remains unknown, with no influence observed for long-term growth. The postnatal administration of systemic corticosteroids has been found to reduce the timing of extubation and improve respiratory outcomes. Dexamethasone appears to be more effective than hydrocortisone, despite causing a higher rate of systemic hypertension and hyperglycemia. However, in the majority of RCTs analyzed, there were no differences in the adverse effects related to postnatal corticosteroid administration.

Conclusion

Dexamethasone administered during the neonatal period appears to be more effective than hydrocortisone in terms of respiratory outcomes; however, caution should be taken when administering dexamethasone. Data derived from current evidence, including meta-analyses, are inconclusive on the long-term effects of the administration of systemic steroids in preterm infants or the possibility of neurodevelopmental consequences.

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 at 24 months corrected age in extremely preterm infants treated with dexamethasone alternatives during the late postnatal period: a cohort study

The administration of dexamethasone has been associated with suboptimal neurodevelopment. We aimed to compare the development of extremely premature infants treated or not with alternatives to dexamethasone: betamethasone, hydrocortisone hemisuccinate. This retrospective cohort study included infants born before 29 weeks of gestational age, treated or not with late (day ≥ 7) postnatal steroids (betamethasone, hydrocortisone hemisuccinate). The neurodevelopment outcome was evaluated at 24 months corrected age, after adjustment on comorbidities of extreme prematurity. In order to analyse their overall development, data about growth and respiratory outcomes were collected. Among the 192 infants included, 59 (30.7%) received postnatal steroids. Suboptimal neurodevelopment concerned 37/59 (62.7%) postnatal steroid-treated and 43/133 (38.1%; p = 0.002) untreated infants. However, in multivariable analysis, only severe neonatal morbidity (p = 0.007) and male gender (p = 0.027) were associated with suboptimal neurodevelopment outcome at 24 months.  Conclusions: Betamethasone or hydrocortisone hemisuccinate treatment was not an independent risk for suboptimal neurological development, growth and respiratory outcomes assessed at 24 months corrected age in extremely premature infants.  Registration number: The study was registered on the ClinicalTrials.gov register: NCT05055193. What is Known: • Late postnatal steroids are used to treat bronchopulmonary dysplasia • Meta-analyses warned against the neurological risk of dexamethasone use during neonatal period. Early or late hydrocortisone hemisuccinate has been evaluated in multiple studies, none of which have reported an adverse effect on neurodevelopment at least to 2 years. Data about the use of betamethasone are scarce. What is New: • The risk of suboptimal neurodevelopment was higher among extremely premature infants who received postnatal steroids when compared to those who did not. • Betamethasone and hydrocortisone hemisuccinate treatment was not an independent risk factor for suboptimal neurodevelopment at 24 months corrected age.

The impact of early tracheostomy on neurodevelopmental outcomes of infants with severe bronchopulmonary dysplasia exposed to postnatal corticosteroids

OBJECTIVE

To compare the cognitive, language and motor scores of infants with severe BPD exposed to postnatal corticosteroids (PCS) and had early (ET), late (LT) or no tracheostomy (NT).

METHODS

Retrospective study was designed to compare the developmental outcomes of 71 infants born between 2010 and 2017 with severe BPD exposed to PCS and had ET (≤122 days), LT (>122 days), or NT.

RESULTS

Cognitive scores were lower in LT versus NT and ET (p = 0.050); motor scores were worse in LT versus NT and ET (p = 0.004). Dexamethasone use was higher in LT versus NT and ET (p = 0.040). Adjusted for PCS, odds for major cognitive impairment were 90% less in ET versus LT. Trend for improved language and motor outcomes was seen in ET versus LT.

CONCLUSION

Infants with severe BPD exposed to PCS and had ET had significantly better cognitive, and trend toward improved language and motor outcomes.

Trends in neonatal morbidity and mortality for very low birthweight infants: a 20-year single-center experience

OBJECTIVE

To describe trends in mortality and morbidity rates of very low birth weight infants as well as their pre-, peri- and postnatal characteristics over a period of 20 years' time.

METHODS

Retrospective study in all very low birth weight infants admitted to the neonatal intensive care unit of the University Hospitals Ghent from 1 January 2000, to 31 December 2020. Mortality was the primary outcome variable with major morbidities being co-primary outcome variables. Pre-, peri- and postnatal characteristics are secondary outcome variables. We compared pre-, peri- and postnatal characteristics, as well as major morbidities between different groups with comparable rates of mortality.

RESULTS

We included a total of 2037 very low birth weight infants and divided them in 3 epochs based on stepwise reductions in mortality in 2008 and 2013: 2000-2007 (n = 718), 2008-2012 (n = 506) and 2013-2020 (n = 813). Mortality decreased significantly over the years in all gestational ages, but predominantly in those with the youngest gestational age. Changes in obstetric and neonatal care were observed over time. Most significant changes were the increased use of antenatal corticosteroids, magnesium sulfate and surfactant. Intraventricular hemorrhage grade III/IV decreased significantly in all gestational ages. Significant increase in retinopathy of prematurity was observed. Bronchopulmonary dysplasia at 36 weeks and discharge home with oxygen is increasing in the total group. In those born below 26 weeks a slight increase in all major morbidities was observed especially of patent ductus arteriosus and retinopathy of prematurity. Increase of all other major morbidities seems to stabilize in epoch 3. The number of infants surviving without any major morbidity increases to almost 1/2 in all very low birth weight infants and to 1/10 in those born 24-25 weeks gestation.

CONCLUSION

Analysis of the real-life experience showed that survival in very low birth weight infants significantly increased over time. Evolution of major morbidities will have to be carefully watched in the future.

Interaction of hydrocortisone and illness severity on head growth in cohort of ELBW infants

BACKGROUND

Extremely low birth weight (ELBW) infants comprise a fragile population at risk for neurodevelopmental disabilities (NDD). Systemic steroids were previously associated with NDD, but more recent studies suggest hydrocortisone (HCT) may improve survival without increasing NDD. However, the effects of HCT on head growth adjusted for illness severity during NICU hospitalization are unknown. Thus, we hypothesize that HCT will protect head growth, accounting for illness severity using a modified neonatal Sequential Organ Failure Assessment (M-nSOFA) score.

METHODS

We conducted a retrospective study that included infants born at 23-29 weeks gestational age (GA) and < 1000 g. Our study included 73 infants, 41% of whom received HCT.

RESULTS

We found negative correlations between growth parameters and age, similar between HCT and control patients. HCT-exposed infants had lower GA but similar normalized birth weights; HCT-exposed infants also had higher illness severity and longer lengths of hospital stay. We found an interaction between HCT exposure and illness severity on head growth, such that infants exposed to HCT had better head growth compared to those not exposed to HCT when adjusted for illness severity.

CONCLUSION

These findings emphasize the importance of considering patient illness severity and suggest that HCT use may offer additional benefits not previously considered.

IMPACT

This is the first study to assess the relationship between head growth and illness severity in extremely preterm infants with extremely low birth weights during their initial NICU hospitalization. Infants exposed to hydrocortisone (HCT) were overall more ill than those not exposed, yet HCT exposed infants had better preserved head growth relative to illness severity. Better understanding of the effects of HCT exposure on this vulnerable population will help guide more informed decisions on the relative risks and benefits for HCT use.

Postnatal Corticosteroids To Prevent Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a common, severe chronic respiratory disease that affects very preterm infants. In utero and postnatal exposure to proinflammatory stimuli contribute to the pathophysiology of BPD. Corticosteroids, because of their potent anti-inflammatory properties, may decrease respiratory morbidity and reduce the risk of BPD in very preterm infants. However, these medications can have adverse effects on the developing brain and other organ systems. This review examines current evidence on the risks and benefits of postnatal corticosteroids used to prevent BPD in preterm infants.

Management of bronchopulmonary dysplasia in Japan: A nationwide survey

BACKGROUND

The incidence of bronchopulmonary dysplasia (BPD) and respiratory management practices for extremely low birth weight infants (ELBWIs) widely vary among institutions and countries.

AIMS

To clarify the variation and characteristics of the current practices of Japanese neonatologists managing patients with BPD.

STUDY DESIGN

Questionnaire-based survey.

PARTICIPANTS

Level II and III perinatal centers certified by the Japan Society of Perinatal and Neonatal Medicine.

OUTCOME MEASURES

Policies of the neonatal intensive care units (NICUs) regarding respiratory care and medications for BPD prevention and treatment.

RESULTS

A total of 76 % of facilities (207/274) responded to our survey. The response rates of level III and II facilities were 91 % (102/112) and 35 % (105/296), respectively. INtubation-SURfactant-Extubation and Less Invasive Surfactant Administration methods were performed in 23 % (47/206) and 1 % (3/206) of facilities, respectively. For the prophylactic purpose, systemic and inhaled steroids were administered "frequently" or "occasionally" in 14 % (28/205) and 42 % (86/204) of NICUs, respectively. For the therapeutic purpose, systemic and inhaled steroids were administered "frequently" or "occasionally" in 84 % (171/204) and 29 % (59/204) of NICUs, respectively. Approximately half of the NICUs (99/202) used volume-targeted ventilation (VTV) "frequently" or "occasionally" in progressing BPD. High-frequency oscillation ventilation (HFOV) was used for progressing BPD "frequently" and "occasionally" in 89 % (180/202) of the facilities.

CONCLUSIONS

Our study provided an overview and characteristics of BPD management in Japan in recent years. Noninvasive approaches with surfactant administration remain not widely used in Japan. HFOV is a widely accepted management for progressing BPD.

Rapamycin attenuates pyroptosis by suppressing mTOR phosphorylation and promoting autophagy in LPS-induced bronchopulmonary dysplasia

PURPOSE/AIM

Bronchopulmonary dysplasia (BPD) is associated with poor survival in preterm infants. Intrauterine infection can aggravate the degree of obstruction of alveolar development in premature infants; however, the pathogenic mechanism remains unclear. In this study, we sought to determine whether pyroptosis could be inhibited by downregulating mammalian target of rapamycin (mTOR) activation and inducing autophagy in BPD-affected lung tissue.

MATERIALS AND METHODS

We established a neonatal rat model of BPD induced by intrauterine infection via intraperitoneally injecting pregnant rats with lipopolysaccharide (LPS). Subsequently, mTOR levels and pyroptosis were evaluated using immunohistochemistry, immunofluorescence, TUNEL staining, and western blotting. The Shapiro-Wilk test was employed to assess the normality of the experimental data. Unpaired t-tests were used to compare the means between two groups, and comparisons between multiple groups were performed using analysis of variance.

RESULTS

Pyroptosis of lung epithelial cells increased in BPD lung tissues. After administering an mTOR phosphorylation inhibitor (rapamycin) to neonatal rats with BPD, the level of autophagy increased, while the expression of autophagy cargo adaptors, LC3 and p62, did not differ. Following rapamycin treatment, NLRP3, Pro-caspase-1, caspase-1, pro-IL-1β, IL-1β, IL-18/Pro-IL-18, N-GSDMD/GSDMD, Pro-caspase-11, and caspase-11 were negatively regulated in BPD lung tissues. The opposite results were observed after treatment with the autophagy inhibitor MHY1485, showing an increase in pyroptosis and a significant decrease in the number of alveoli in BPD.

CONCLUSIONS

Rapamycin reduces pyroptosis in neonatal rats with LPS-induced BPD by inhibiting mTOR phosphorylation and inducing autophagy; hence, it may represent a potential therapeutic for treating BPD.

The association between patterns of early respiratory disease and diastolic dysfunction in preterm infants

BACKGROUND

This study aims to determine the association between clinical patterns of early respiratory disease and diastolic dysfunction in preterm infants.

METHODS

Preterm infants <29 weeks' gestation underwent cardiac ultrasounds around day 7 and 14-21. Respiratory dysfunction patterns were classified as stable (ST), respiratory deterioration (RD) or early persistent respiratory dysfunction (EPRD) according to oxygen need. Diastolic dysfunction was diagnosed using a multi-parameter approach including left atrial strain (LASR) to help differentiate between cardiac or pulmonary pathophysiology.

RESULTS

98 infants (mean 27 weeks) were included. The prevalence of ST, RD and EPRD was 53%, 21% and 26% respectively. Diastolic dysfunction was more prevalent in the RD and EPRD groups with patent ductus arteriosus and significant growth restriction as risk factors. Not all infants with a PDA developed diastolic dysfunction. LASR was lower in the EPDR group.

CONCLUSION

Respiratory dysfunction patterns are associated with diastolic dysfunction in preterm infants.

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 hydrocortisone-responsive urinary metabolome of premature infants

BACKGROUND

Extremely premature infants are at risk for circulatory collapse or respiratory failure that are often treated with hydrocortisone (HC); however, there is no information on the metabolic consequences of this therapy.

METHODS

Longitudinal urine samples from infants <28 weeks gestation in the Trial of Late Surfactant were analyzed by untargeted UHPLC:MS/MS. Fourteen infants who received a tapering course of HC beginning at 3 mg/kg/day for ≥9 days were compared to 14 matched control infants. A secondary cross-sectional analysis by logistic regression used urines from 314 infants.

RESULTS

Of 1145 urinary metabolites detected, abundance of 219, representing all the major biochemical pathways, changed at p < 0.05 in the HC-treated group with 90% decreasing; 3 cortisol derivatives increased ~2-fold with HC therapy. Only 11% of regulated metabolites remained responsive at the lowest HC dose. Regulated metabolites included two steroids and thiamin that are associated with lung inflammation in infants. HC responsiveness was confirmed in 57% of metabolites by cross-sectional analysis.

CONCLUSIONS

HC treatment of premature infants influenced in a dose-dependent manner abundance of 19% of identified urinary metabolites of diverse biochemical systems, primarily reducing concentrations. These findings indicate that exposure to HC reversibly impacts the nutritional status of premature infants.

IMPACT

Hydrocortisone treatment of premature infants with respiratory failure or circulatory collapse alters levels of a subset of urinary metabolites representing all major biochemical pathways. This is the first description of the scope, magnitude, timing and reversibility of metabolomic changes in infants in response to hydrocortisone, and it confirms corticosteroid regulation of three biochemicals that are associated with lung inflammatory status. The findings indicate a dose-dependency of hydrocortisone for metabolomic and anti-inflammatory effects, that prolonged therapy may lower the supply of many nutrients, and that monitoring concentrations of cortisol and inflammation markers may be a useful clinical approach during corticosteroid therapy.

Hormonal Determinants of Growth and Weight Gain in the Human Fetus and Preterm Infant

The factors controlling linear growth and weight gain in the human fetus and newborn infant are poorly understood. We review here the changes in linear growth, weight gain, lean body mass, and fat mass during mid- and late gestation and the early postnatal period in the context of changes in the secretion and action of maternal, placental, fetal, and neonatal hormones, growth factors, and adipocytokines. We assess the effects of hormonal determinants on placental nutrient delivery and the impact of preterm delivery on hormone expression and postnatal growth and metabolic function. We then discuss the effects of various maternal disorders and nutritional and pharmacologic interventions on fetal and perinatal hormone and growth factor production, growth, and fat deposition and consider important unresolved questions in the field.

Systemic corticosteroids for the prevention of bronchopulmonary dysplasia, a network meta-analysis

BACKGROUND

Despite considerable improvement in outcomes for preterm infants, rates of bronchopulmonary dysplasia (BPD) remain high, affecting an estimated 33% of very low birthweight infants, with corresponding long-term respiratory and neurosensory issues. Systemic corticosteroids can address the inflammation underlying BPD, but the optimal regimen for prevention of this disease, balancing of the benefits with the potentially meaningful risks of systemic corticosteroids, continues to be a medical quandary. Numerous studies have shown that systemic corticosteroids, particularly dexamethasone and hydrocortisone, effectively treat or prevent BPD. However, concerning short and long-term side effects have been reported and the optimal approach to corticosteroid treatment remains unclear.

OBJECTIVES

To determine whether differences in efficacy and safety exist between high-dose dexamethasone, moderate-dose dexamethasone, low-dose dexamethasone, hydrocortisone, and placebo in the prevention of BPD, death, the composite outcome of death or BPD, and other relevant morbidities, in preterm infants through a network meta-analysis, generating both pairwise comparisons between all treatments and rankings of the treatments.

SEARCH METHODS

We searched the Cochrane Library for all systematic reviews of systemic corticosteroids for the prevention of BPD and searched for completed and ongoing studies in the following databases in January 2023: Cochrane Central Register of Controlled Trials, MEDLINE, Embase, and clinical trial databases.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) in preterm infants (< 37 weeks' gestation) at risk for BPD that evaluated systemic corticosteroids (high-dose [≥ 4 mg/kg cumulative dose] dexamethasone, moderate-dose [≥ 2 to < 4 mg/kg] dexamethasone, low-dose [< 2 mg/kg] dexamethasone, or hydrocortisone) versus control or another systemic corticosteroid.

DATA COLLECTION AND ANALYSIS

Our main information sources were the systematic reviews, with reference to the original manuscript only for data not included in these reviews. Teams of two paired review authors independently performed data extraction, with disagreements resolved by discussion. Data were entered into Review Manager 5 and exported to R software for network meta-analysis (NMA). NMA was performed using a frequentist model with random-effects. Two separate networks were constructed, one for early (< seven days) initiation of treatment and one for late (≥ seven days) treatment initiation, to reflect the different patient populations evaluated. We assessed the certainty of evidence derived from the NMA for our primary outcomes using principles of the GRADE framework modified for application to NMA.

MAIN RESULTS

We included 59 studies, involving 6441 infants, in our analyses. Only six of the included studies provided direct comparisons between any of the treatment (dexamethasone or hydrocortisone) groups, forcing network comparisons between treatments to rely heavily on indirect evidence through comparisons with placebo/no treatment groups. Thirty-one studies evaluated early corticosteroid treatment, 27 evaluated late corticosteroid treatment, and one study evaluated both early and late corticosteroid treatments. Early treatment (prior to seven days after birth): Benefits:NMA for early treatment showed only moderate-dose dexamethasone to decrease the risk of BPD at 36 weeks' postmenstrual age (PMA) compared with control (RR 0.56, 95% CI 0.39 to 0.80; moderate-certainty evidence), although the other dexamethasone dosing regimens may have similar effects compared with control (high-dose dexamethasone, RR 0.71, 95% CI 0.50 to 1.01; low-certainty evidence; low-dose dexamethasone, RR 0.83, 95% CI 0.67 to 1.03; low-certainty evidence). Other early treatment regimens may have little or no effect on the risk of death at 36 weeks' PMA. Only moderate-dose dexamethasone decreased the composite outcome of death or BPD at 36 weeks' PMA compared with control (RR 0.77, 95% CI 0.60 to 0.98; moderate-certainty evidence).

HARMS

Low-dose dexamethasone increased the risk for cerebral palsy (RR 1.92, 95% CI 1.12 to 3.28; moderate-certainty evidence) compared with control. Hydrocortisone may decrease the risk of major neurosensory disability versus low-dose dexamethasone (RR 0.65, 95% CI 0.41 to 1.01; low-certainty evidence). Late treatment (at seven days or later after birth): Benefits: NMA for late treatment showed high-dose dexamethasone to decrease the risk of BPD both versus hydrocortisone (RR 0.66, 95% CI 0.51 to 0.85; low-certainty evidence) and versus control (RR 0.72, CI 0.59 to 0.87; moderate-certainty evidence). The late treatment regimens evaluated may have little or no effect on the risk of death at 36 weeks' PMA. High-dose dexamethasone decreased risk for the composite outcome of death or BPD compared with all other treatments (control, RR 0.69, 95% CI 0.59 to 0.80, high-certainty evidence; hydrocortisone, RR 0.69, 95% CI 0.58 to 0.84, low-certainty evidence; low-dose dexamethasone, RR 0.73, 95% CI 0.60 to 0.88, low-certainty evidence; moderate-dose dexamethasone, RR 0.76, 95% CI 0.62 to 0.93, low-certainty evidence).

HARMS

No effect was observed for the outcomes of major neurosensory disability or cerebral palsy. The evidence for the primary outcomes was of overall low certainty, with notable deductions for imprecision and heterogeneity across the networks.

AUTHORS' CONCLUSIONS

While early treatment with moderate-dose dexamethasone or late treatment with high-dose dexamethasone may lead to the best effects for survival without BPD, the certainty of the evidence is low. There is insufficient evidence to guide this therapy with regard to plausible adverse long-term outcomes. Further RCTs with direct comparisons between systemic corticosteroid treatments are needed to determine the optimal treatment approach, and these studies should be adequately powered to evaluate survival without major neurosensory disability.

MALAT1 binds to miR-188-3p to regulate ALOX5 activity in the lung inflammatory response of neonatal bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) causes high morbidity and mortality in infants, but no effective preventive or therapeutic agents have been developed to combat BPD. In this study, we assessed the expression of MALAT1 and ALOX5 in peripheral blood mononuclear cells from BPD neonates, hyperoxia-induced rat models and lung epithelial cell lines. Interestingly, we found upregulated expression of MALAT1 and ALOX5 in the experimental groups, along with upregulated expression of proinflammatory cytokines. According to bioinformatics prediction, MALAT1 and ALOX5 simultaneously bind to miR-188-3p, which was downregulated in the experimental groups above. Silencing MALAT1 or ALOX5 and overexpressing miR-188-3p inhibited apoptosis and promoted the proliferation of hyperoxia-treated A549 cells. Suppressing MALAT1 or overexpressing miR-188-3p increased the expression levels of miR-188-3p but decreased the expression levels of ALOX5. Moreover, RNA immunoprecipitation (RIP) and luciferase assays showed that MALAT1 directly targeted miR-188-3p to regulate ALOX5 expression in BPD neonates. Collectively, our study demonstrates that MALAT1 regulates ALOX5 expression by binding to miR-188-3p, providing novel insights into potential therapeutics for BPD treatment.

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.

Heterogeneity of Treatment Effects of Hydrocortisone by Risk of Bronchopulmonary Dysplasia or Death Among Extremely Preterm Infants in the National Institute of Child Health and Human Development Neonatal Research Network Trial: A Secondary Analysis of a Randomized Clinical Trial

Importance

Extremely preterm infants who develop bronchopulmonary dysplasia (BPD) are at a higher risk for adverse pulmonary and neurodevelopmental outcomes. In the National Institute of Child Health and Human Development Neonatal Research Network (NICHD NRN) Hydrocortisone Trial, hydrocortisone neither reduced rates of BPD or death nor increased rates of neurodevelopmental impairment (NDI) or death.

Objective

To determine whether estimated risk for grades 2 to 3 BPD or death is associated with the effect of hydrocortisone on the composite outcomes of (1) grades 2 to 3 BPD or death and (2) moderate or severe NDI or death.

Design, Setting, and Participants

This secondary post hoc analysis used data from the NICHD NRN Hydrocortisone Trial, which was a double-masked, placebo-controlled, randomized clinical trial conducted in 19 US academic centers. The NICHD HRN Hydrocortisone Trial enrolled infants born at a gestational age of less than 30 weeks who received mechanical ventilation for at least 7 days, including at the time of enrollment, and who were aged 14 to 28 postnatal days. Infants were enrolled between August 22, 2011, and February 4, 2018, with follow-up between 22 and 26 months of corrected age completed on March 29, 2020. Data were analyzed from September 13, 2021, to March 25, 2023.

Intervention

Infants were randomized to 10 days of hydrocortisone or placebo treatment.

Main Outcomes and Measures

Infants' baseline risk of grades 2 to 3 BPD or death was estimated using the NICHD Neonatal BPD Outcome Estimator. Differences in absolute and relative treatment effects by baseline risk were evaluated using interaction terms in models fitted to the efficacy outcome of grades 2 to 3 BPD or death and the safety outcome of moderate or severe NDI or death by follow-up.

Results

Among the 799 infants included in the analysis (421 boys [52.7%]), the mean (SD) gestational age was 24.9 (1.5) weeks, and the mean (SD) birth weight was 715 (167) g. The mean estimated baseline risk for grades 2 to 3 BPD or death was 54% (range, 18%-84%) in the study population. The interaction between treatment group and baseline risk was not statistically significant on a relative or absolute scale for grades 2 to 3 BPD or death; the size of the effect ranged from a relative risk of 1.13 (95% CI, 0.82-1.55) in quartile 1 to 0.94 (95% CI, 0.81-1.09) in quartile 4. Similarly, the interaction between treatment group and baseline risk was not significant on a relative or absolute scale for moderate or severe NDI or death; the size of the effect ranged from a relative risk of 1.04 (95% CI, 0.80-1.36) in quartile 1 to 0.99 (95% CI, 0.80-1.22) in quartile 4.

Conclusions and Relevance

In this secondary analysis of a randomized clinical trial, the effect of hydrocortisone vs placebo was not appreciably modified by baseline risk for grades 2 to 3 BPD or death.

Trial Registration

ClinicalTrials.gov Identifier: NCT01353313.

Assessment of Corticosteroid Therapy and Death or Disability According to Pretreatment Risk of Death or Bronchopulmonary Dysplasia in Extremely Preterm Infants

Importance

Meta-analyses suggest that corticosteroids may be associated with increased survival without cerebral palsy in infants at high risk of bronchopulmonary dysplasia (BPD) but are associated with adverse neurologic outcomes in low-risk infants. Whether this association exists in contemporary practice is uncertain because most randomized clinical trials administered corticosteroids earlier and at higher doses than currently recommended.

Objective

To evaluate whether the pretreatment risk of death or grade 2 or 3 BPD at 36 weeks' postmenstrual age modified the association between postnatal corticosteroid therapy and death or disability at 2 years' corrected age in extremely preterm infants.

Design, Setting, and Participants

This cohort study analyzed data on 482 matched pairs of infants from 45 participating US hospitals in the National Institute of Child Health and Human Development Neonatal Research Network Generic Database (GDB). Infants were included in the cohort if they were born at less than 27 weeks' gestation between April 1, 2011, and March 31, 2017; survived the first 7 postnatal days; and had 2-year death or developmental follow-up data collected between January 2013 and December 2019. Corticosteroid-treated infants were propensity score matched with untreated controls. Data were analyzed from September 1, 2019, to November 30, 2022.

Exposure

Systemic corticosteroid therapy to prevent BPD that was initiated between day 8 and day 42 after birth.

Main Outcomes and Measures

The primary outcome was death or moderate to severe neurodevelopmental impairment at 2 years' corrected age. The secondary outcome was death or moderate to severe cerebral palsy at 2 years' corrected age.

Results

A total of 482 matched pairs of infants (mean [SD] gestational age, 24.1 [1.1] weeks]; 270 males [56.0%]) were included from 656 corticosteroid-treated infants and 2796 potential controls. Most treated infants (363 [75.3%]) received dexamethasone. The risk of death or disability associated with corticosteroid therapy was inversely associated with the estimated pretreatment probability of death or grade 2 or 3 BPD. The risk difference for death or neurodevelopmental impairment associated with corticosteroids decreased by 2.7% (95% CI, 1.9%-3.5%) for each 10% increase in the pretreatment risk of death or grade 2 or 3 BPD. This risk transitioned from estimated net harm to benefit when the pretreatment risk of death or grade 2 or 3 BPD exceeded 53% (95% CI, 44%-61%). For death or cerebral palsy, the risk difference decreased by 3.6% (95% CI, 2.9%-4.4%) for each 10% increase in the risk of death or grade 2 or 3 BPD and transitioned from estimated net harm to benefit at a pretreatment risk of 40% (95% CI, 33%-46%).

Conclusions and Relevance

Results of this study suggested that corticosteroids were associated with a reduced risk of death or disability in infants at moderate to high pretreatment risk of death or grade 2 or 3 BPD but with possible harm in infants at lower risk.

Trends, Characteristic, and Outcomes of Preterm Infants Who Received Postnatal Corticosteroid: A Cohort Study from 7 High-Income Countries

INTRODUCTION

Our objective was to evaluate the temporal trend of systemic postnatal steroid (PNS) receipt in infants of 24-28 weeks' gestational age, identify characteristics associated with PNS receipt, and correlate PNS receipt with the incidence of bronchopulmonary dysplasia (BPD) and BPD/death from an international cohort included in the iNeo network.

METHODS

We conducted a retrospective study using data from 2010 to 2018 from seven international networks participating in iNeo (Canada, Finland, Israel, Japan, Spain, Sweden, and Switzerland). Neonates of 24 and 28 weeks' gestational age who survived 7 days and who received PNS were included. We assessed temporal trend of rates of systemic PNS receipt and BPD/death.

RESULTS

A total of 47,401 neonates were included. The mean (SD) gestational age was 26.4 (1.3) weeks and birth weight was 915 (238) g. The PNS receipt rate was 21% (12-28% across networks) and increased over the years (18% in 2010 to 26% in 2018; p < 0.01). The BPD rate was 39% (28-44% across networks) and remained unchanged over the years (35.2% in 2010 to 35.0% in 2018). Lower gestation, male sex, small for gestational age status, and presence of persistent ductus arteriosus (PDA) were associated with higher rates of PNS receipt, BPD, and BPD/death.

CONCLUSION

The use of PNS in extremely preterm neonates increased, but there was no correlation between increased use and the BPD rate. Research is needed to determine the optimal timing, dose, and indication for PNS use in preterm neonates.

Postnatal corticosteroid exposure in very preterm infants: A French cohort study

Background: Postnatal corticosteroids (PC) are widely used in very preterm infants. International reports and national multicenter trials describe a marked variability across countries and inter-sites, in the use of PC. Few information is available on therapeutic indications and prescription characteristics of PC.

Aim: The main objective of this study was to describe the exposure to PC in a large cohort of preterm infants born at less than 32 weeks of gestation, according to the prescription data of 41 tertiary-care NICUs in France. Secondary objectives were to describe therapeutic indications, day of life (DOL) of the first exposure, route of administration, duration, cumulative dose for each drug, and differences in exposure rates across centers.

Methods: We conducted a prospective observational cohort analysis from January 2017 to December 2021, in 41 French tertiary-care NICUs using the same computerized order-entry system.

Results: In total, 13,913 infants [birth weight 1144.8 (±365.6) g] were included. Among them, 3633 (26.1%) were exposed to PC, 21.8% by systemic and 10.1% by inhaled route. Within the study population, 1,992 infants (14.3%) received the first corticosteroid treatment in the first week of life and 1641 (11.8%) after DOL 7. The more frequent indications were prevention and/or treatment of bronchopulmonary dysplasia, and arterial hypotension. Hydrocortisone was the more often prescribed molecule. For systemic PC the first exposure occurred in mean at DOL 9.4 (±13.5), mean duration of treatment was 10.3 (±14.3) days, and the cumulative dose (expressed as the equivalent dose of hydrocortisone) was in median [IQR] 9.0 [5.5–28.8] mg/kg. For inhaled PC, the first exposure occurred in mean at DOL 34.1 (±19.7), and mean duration of treatment 28.5 (±24.4) days. The exposure rate ranged from a minimum of 5% to a maximum of 56% among centers, and significantly increased over the study period (p &lt; 0.0001).

Conclusion: In this French cohort of very preterm infants, around one patient out to five was exposed to PC during hospital stay in the NICU. The exposure occurred early, starting from the first week of life. Exposure rate widely varied among centers. Pharmacoepidemiology studies are useful to increase knowledge on corticosteroid utilization patterns in preterm infants.

Oxygen toxicity causes cyclic damage by destabilizing specific Fe-S cluster-containing protein complexes

Oxygen is toxic across all three domains of life. Yet, the underlying molecular mechanisms remain largely unknown. Here, we systematically investigate the major cellular pathways affected by excess molecular oxygen. We find that hyperoxia destabilizes a specific subset of Fe-S cluster (ISC)-containing proteins, resulting in impaired diphthamide synthesis, purine metabolism, nucleotide excision repair, and electron transport chain (ETC) function. Our findings translate to primary human lung cells and a mouse model of pulmonary oxygen toxicity. We demonstrate that the ETC is the most vulnerable to damage, resulting in decreased mitochondrial oxygen consumption. This leads to further tissue hyperoxia and cyclic damage of the additional ISC-containing pathways. In support of this model, primary ETC dysfunction in the Ndufs4 KO mouse model causes lung tissue hyperoxia and dramatically increases sensitivity to hyperoxia-mediated ISC damage. This work has important implications for hyperoxia pathologies, including bronchopulmonary dysplasia, ischemia-reperfusion injury, aging, and mitochondrial disorders.

Association Between Enteral Supplementation With High-Dose Docosahexaenoic Acid and Risk of Bronchopulmonary Dysplasia in Preterm Infants: A Systematic Review and Meta-analysis

IMPORTANCE

High-dose docosahexaenoic acid (DHA), a long-chain polyunsaturated fatty acid, may affect the risk of bronchopulmonary dysplasia (BPD). However, high-level summative evidence supporting such clinical association in very preterm infants is lacking.

OBJECTIVE

To examine the association between enteral supplementation with high-dose DHA during the neonatal period and the risk of BPD in preterm infants born at less than 29 weeks' gestation.

DATA SOURCES

PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials, medRxiv, and ClinicalTrials.gov were searched from inception to August 1, 2022, for eligible articles with no language restrictions.

STUDY SELECTION

Randomized clinical trials (RCTs) were eligible for inclusion (1) if their interventions involved direct administration of a minimum DHA supplementation of 40 mg/kg/d or breast milk or formula feeding of at least 0.4% of total fatty acids, and (2) if they reported data on either BPD, death, BPD severity, or a combined outcome of BPD and death.

DATA EXTRACTION AND SYNTHESIS

Two investigators completed independent review of titles and abstracts, full text screening, data extraction, and quality assessment using the Cochrane Risk of Bias 2.0. Risk ratios (RRs) with 95% CIs were pooled using random-effect meta-analyses.

MAIN OUTCOMES AND MEASURES

Primary outcome was BPD using trial-specific definitions, which was further stratified for RCTs that used a more stringent BPD definition based on systematic pulse oximetry assessment at 36 weeks' postmenstrual age. Other outcomes were BPD, death, BPD severity, or combined BPD and death.

RESULTS

Among the 2760 studies screened, 4 RCTs were included, which involved 2304 infants (1223 boys [53.1%]; mean [SD] gestational age, 26.5 [1.6] weeks). Enteral supplementation with high-dose DHA was associated with neither BPD (4 studies [n = 2186 infants]; RR, 1.07 [95% CI, 0.86-1.34]; P = .53; I2 = 72%) nor BPD or death (4 studies [n = 2299 infants]; RR, 1.04 [95% CI, 0.91-1.18]; P = .59; I2 = 61%). However, an inverse association with BPD was found in RCTs that used a more stringent BPD definition (2 studies [n = 1686 infants]; RR, 1.20 [95% CI, 1.01-1.42]; P = .04; I2 = 48%). Additionally, DHA was inversely associated with moderate-to-severe BPD (3 studies [n = 1892 infants]; RR, 1.16 [95% CI, 1.04-1.29]; P = .008; I2 = 0%).

CONCLUSIONS AND RELEVANCE

Results of this study showed that enteral supplementation with high-dose DHA in the neonatal period was not associated overall with BPD, but an inverse association was found in the included RCTs that used a more stringent BPD definition. These findings suggest that high-dose DHA supplementation should not be recommended to prevent BPD in very preterm infants.

Pollen-Inspired Shell-Core Aerosol Particles Capable of Brownian Motion for Pulmonary Vascularization

Nebulization is the most widely used respiratory delivery technique with non-invasive properties. However, nebulized drugs often fail to function due to the excretion and immune clearance of the respiratory system. In this work, inspired by pollen in nature, novel shell-core aerosol particles (APs) capable of Brownian motion are constructed for respiratory delivery. Drugs-loaded poly(lactic-co-glycolic acid) nanoparticles are prepared by emulsification to form the inner core, and the membranes of macrophages are extracted to form the outer shell. The optimized size and the shell-core structure endow APs with Brownian motion and atomization stability, thus enabling the APs to reach the bronchi and alveoli deeply for effective deposition. Camouflaging the macrophage membranes equips the APs with immune evasion. In vitro experiments prove that deferoxamine (DFO)-loaded APs (DFO@APs) can promote the angiogenesis of human umbilical vein endothelial cells. A hyperoxia-induced bronchopulmonary dysplasia (BPD) model is constructed to validate the efficiency of DFO@APs. In BPD mice, DFO@APs can release DFO in the alveolar interstitium, thus promoting the reconstruction of microvasculature, ultimately inducing lung development for treating BPD. In conclusion, this study develops "pollen"-inspired shell-core aerosol particles capable of Brownian motion, which provides a novel idea and theoretical basis for respiratory administration.

Prevention for moderate or severe BPD with intravenous infusion of autologous cord blood mononuclear cells in very preterm infants-a prospective non-randomized placebo-controlled trial and two-year follow up outcomes

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the primary severe complication of preterm birth. Severe BPD was associated with higher risks of mortality, more postnatal growth failure, long term respiratory and neurological developmental retardation. Inflammation plays a central role in alveolar simplification and dysregulated vascularization of BPD. There is no effective treatment to improve BPD severity in clinical practice. Our previous clinical study showed autologous cord blood mononuclear cells (ACBMNCs) infusion could reduce the respiratory support duration safely and potential improved BPD severity. Abundant preclinical studies have reported the immunomodulation effect as an important mechanism underlying the beneficial results of stem cell therapies in preventing and treating BPD. However, clinical studies assessing the immunomodulatory effect after stem cells therapy were rare. This study was to investigate the effect of ACBMNCs infusion soon after birth on prevention for severe BPD and long term outcomes in very preterm neonates. The immune cells and inflammatory biomarkers were detected to investigate the underlying immunomodulatory mechanisms.

METHODS

This single-center, prospective, investigator-initiated, non-randomized trial with blinded outcome assessment aimed to assess the effect of a single intravenous infusion of ACBMNCs in preventing severe BPD (moderate or severe BPD at 36 weeks of gestational age or discharge home) in surviving very preterm neonates less than 32 gestational weeks. Patients admitted to the Neonatal Intensive Care Unit (NICU) of Guangdong Women and Children Hospital from July 01, 2018 to January 1, 2020 were assigned to receiving a targeted dosage of 5 × 10⁷ cells/kg ACBMNC or normal saline intravenously within 24 h after enrollment. Incidence of moderate or severe BPD in survivors were investigated as the primary short term outcome. Growth, respiratory and neurological development were assessed as long term outcomes at corrected age of 18-24 month-old. Immune cells and inflammatory biomarkers were detected for potential mechanism investigation. The trial was registered at ClinicalTrials.gov (NCT02999373).

FINDINGS

Six-two infants were enrolled, of which 29 were enrolled to intervention group, 33 to control group. Moderate or severe BPD in survivors significantly decreased in intervention group (adjusted p = 0.021). The number of patients needed to treat to gain one moderate or severe BPD-free survival was 5 (95% confidence interval: 3-20). Survivors in the intervention group had a significantly higher chance to be extubated than infants in the control group (adjusted p = 0.018). There was no statistical significant difference in total BPD incidence (adjusted p = 0.106) or mortality (p = 1.000). Incidence of developmental delay reduced in intervention group in long term follow-up (adjusted p = 0.047). Specific immune cells including proportion of T cells (p = 0.04) and CD4⁺ T cells in lymphocytes (p = 0.03), and CD4+ CD25+ forkhead box protein 3 (FoxP3)+ regulatory T cells in CD4+ T cells increased significantly after ACBMNCs intervention (p ＜ 0.001). Anti-inflammatory factor IL-10 was higher (p = 0.03), while pro-inflammatory factor such as TNF-a (p = 0.03) and C reactive protein (p ＜ 0.001) level was lower in intervention group than in control group after intervention.

INTERPRETATION

ACBMNCs could prevent moderate or severe BPD in surviving very premature neonates and might improve neurodevelopmental outcomes in long term. An immunomodulatory effect of MNCs contributed to the improvement of BPD severity.

FUNDING

This work was supported by National Key R&D Program of China (2021YFC2701700), National Natural Science Foundation of China (82101817, 82171714, 8187060625), Guangzhou science and technology program (202102080104).

The prevention and management strategies for neonatal chronic lung disease

INTRODUCTION

Survival from even very premature birth is improving, but long-term respiratory morbidity following neonatal chronic lung disease (bronchopulmonary dysplasia (BPD)) has not reduced. Affected infants may require supplementary oxygen at home, because they have more hospital admissions particularly due to viral infections and frequent, troublesome respiratory symptoms requiring treatment. Furthermore, adolescents and adults who had BPD have poorer lung function and exercise capacity.

AREAS COVERED

Antenatal and postnatal preventative strategies and management of infants with BPD. A literature review was undertaken using PubMed and Web of Science.

EXPERT OPINION

There are effective preventative strategies which include caffeine, postnatal corticosteroids, vitamin A, and volume guarantee ventilation. Side-effects, however, have appropriately caused clinicians to reduce use of systemically administered corticosteroids to infants only at risk of severe BPD. Promising preventative strategies which need further research are surfactant with budesonide, less invasive surfactant administration (LISA), neurally adjusted ventilatory assist (NAVA) and stem cells. The management of infants with established BPD is under-researched and should include identifying the optimum form of respiratory support on the neonatal unit and at home and which infants will most benefit in the long term from pulmonary vasodilators, diuretics, and bronchodilators.

Mesenchymal Stromal/Stem Cell Extracellular Vesicles and Perinatal Injury: One Formula for Many Diseases

Over the past decades, substantial advances in neonatal medical care have increased the survival of extremely premature infants. However, there continues to be significant morbidity associated with preterm birth with common complications including bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC), neuronal injury such as intraventricular hemorrhage (IVH) or hypoxic ischemic encephalopathy (HIE), as well as retinopathy of prematurity (ROP). Common developmental immune and inflammatory pathways underlie the pathophysiology of such complications providing the opportunity for multisystem therapeutic approaches. To date, no single therapy has proven to be effective enough to prevent or treat the sequelae of prematurity. In the past decade mesenchymal stem/stromal cell (MSC)-based therapeutic approaches have shown promising results in numerous experimental models of neonatal diseases. It is now accepted that the therapeutic potential of MSCs is comprised of their secretome, and several studies have recognized the small extracellular vesicles (sEVs) as the paracrine vector. Herein, we review the current literature on the MSC-EVs as potential therapeutic agents in neonatal diseases and comment on the progress and challenges of their translation to the clinical setting.

Neurocognitive outcomes at age 5 years after prophylactic hydrocortisone in infants born extremely preterm

AIM

To assess the 5-year neurocognitive outcomes of children born extremely preterm exposed to prophylactic hydrocortisone to improve survival without bronchopulmonary dysplasia.

METHOD

This was a prespecified secondary analysis of the PREMILOC clinical trial (trial registration: EudraCT no. 2007-002041-20, NCT00623740). The primary outcome was full-scale IQ based on the Wechsler Preschool and Primary Scale of Intelligence.

RESULTS

Among 109 surviving children recruited at the Robert Debré Children's Hospital, Paris, outcome data were available for 42 out of 56 infants (75%) in the group treated with hydrocortisone and 41 out of 53 (77%) in the placebo group. Mean scores were not significantly different between the two groups on full-scale IQ (hydrocortisone: 91.9 [SD = 13.9], placebo: 86.3 [SD = 15.4]; mean difference = 5.7, 95% confidence interval [CI] = -1.0 to 12.3, p = 0.10); however, working memory and retention ability were significantly better in the group treated with hydrocortisone. In a multivariate logistic regression including potential confounding variables, hydrocortisone treatment was significantly associated with a greater chance to survive at 5 years of age with a full-scale IQ equal to or greater than 90 compared to placebo (adjusted odds ratio = 4.26, 95% CI = 1.47-12.36, p = 0.008).

INTERPRETATION

This exploratory analysis provides reassuring data regarding the long-term neurodevelopmental safety of prophylactic hydrocortisone in infants born extremely preterm.

Postnatal corticosteroid use for prevention or treatment of bronchopulmonary dysplasia in England and Wales 2012-2019: a retrospective population cohort study

OBJECTIVE

Describe the population of babies who do and do not receive postnatal corticosteroids for prevention or treatment of bronchopulmonary dysplasia (BPD).

DESIGN

Retrospective cohort study using data held in the National Neonatal Research Database.

SETTING

National Health Service neonatal units in England and Wales.

PATIENTS

Babies born less than 32 weeks gestation and admitted to neonatal units from 1 January 2012 to 31 December 2019.

MAIN OUTCOMES

Proportion of babies given postnatal corticosteroid; type of corticosteroid; age at initiation and duration, trends over time.

SECONDARY OUTCOMES

Survival to discharge, treatment for retinopathy of prematurity, BPD, brain injury, severe necrotising enterocolitis, gastrointestinal perforation.

RESULTS

8% (4713/62019) of babies born <32 weeks and 26% (3525/13527) born <27 weeks received postnatal corticosteroids for BPD. Dexamethasone was predominantly used 5.3% (3309/62019), followed by late hydrocortisone 1.5%, inhaled budesonide 1.5%. prednisolone 0.8%, early hydrocortisone 0.3% and methylprednisolone 0.05%. Dexamethasone use increased over time (2012: 4.5 vs 2019: 5.8%, p=0.04). Median postnatal age of initiation of corticosteroid course was around 3 weeks for late hydrocortisone, 4 weeks for dexamethasone, 6 weeks for inhaled budesonide, 12 weeks for prednisolone and 16 weeks for methylprednisolone. Babies who received postnatal corticosteroids were born more prematurely, had a higher incidence of comorbidities and a longer length of stay.

CONCLUSIONS

In England and Wales, around 1 in 12 babies born less than 32 weeks and 1 in 4 born less than 27 weeks receive postnatal corticosteroids to prevent or treat BPD. Given the lack of convincing evidence of efficacy, challenges of recruiting to and length of time taken to conduct randomised controlled trial, our data highlight the need to monitor long-term outcomes in children who received neonatal postnatal corticosteroids.

Contributions of the NICHD neonatal research network to the diagnosis, prevention, and treatment of bronchopulmonary dysplasia

Despite improvements in the care and outcomes of infants born extremely preterm, bronchopulmonary dysplasia (BPD) remains a common and frustrating complication of prematurity. This review summarizes the BPD-focused research conducted by the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network (NRN). To improve disease classification and outcome prediction, the NRN developed new data-driven diagnostic criteria for BPD and web-based tools that allow clinicians and investigators to reliably estimate BPD risk in preterm infants. Randomized trials of intramuscular vitamin A and prophylactic nasal continuous positive airway pressure conducted by the NRN have contributed to our current use of these therapies as evidence-based approaches to reduce BPD risk. A recent large, randomized trial of hydrocortisone administered beginning between the 2nd and 4th postnatal weeks provided strong evidence that this therapy promotes successful extubation but does not lower BPD rates. Ongoing studies within the NRN will address important, unanswered questions on the risks and benefits of intratracheal surfactant/corticosteroid combinations and treatment versus expectant management of the patent ductus arteriosus to prevent BPD.

Overview of the neonatal research network: History, contributions, challenges, and future

The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Neonatal Research Network (NRN) has been a leader in neonatal research since 1986. In this chapter we review its history and achievements in (1) continuing observation of populations, treatments, short and longer-term outcomes, and trends over time; (2) "negative studies" (trials with non-significant primary outcomes) and trials stopped for futility or adverse events, which have influenced practice and subsequent trial design; and, (3) landmark trials that have changed neonatal care. Its consistent framework has enabled the NRN to be a pioneer in conducting longer-term, school-age follow-up. Leveraging its established infrastructure, the NRN has also partnered with other NIH institutes, governmental agencies, and industry to more effectively advance neonatal care. As current examples of its evolution with changing times, the Network has instituted a process to open specific network trials to external institutions and is adding a parent and participant component to future endeavors.

Early neurodevelopmental follow-up in the NICHD neonatal research network: Advancing neonatal care and outcomes, opportunities for the future

At the inception of the Eunice Kennedy Shriver National Institute of Child Health and Development Neonatal Research Network (NRN), provision of care for extremely preterm (EPT) infants was considered experimental. The NRN Follow-up Study Group, initiated in 1993, developed infrastructure with certification processes and standards, allowing the NRN to assess 2-year outcomes for EPT and to provide important metrics for randomized clinical trials. This chapter will review the NRN Follow-up Study Group's contributions to understanding factors related to improved neurodevelopmental, behavioral, and social-emotional outcomes of EPT infants. We will also discuss follow up challenges, including reassessing which outcomes are most meaningful for parents and investigators. Finally, we will explore how outcome studies have informed clinical decisions and ethical considerations, given limitations of prediction of complex later childhood outcomes from early neurodevelopmental findings.

Contributions of the NICHD neonatal research network's generic database to documenting and advancing the outcomes of extremely preterm infants

The Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network (NRN) maintains a database of extremely preterm infants known as the Generic Database (GDB). Begun in 1987, this database now includes more than 91,000 infants, most of whom are extremely preterm (<29 weeks gestation). The GDB has been the backbone of the NRN, providing high quality, prospectively collected data to study the changing epidemiology of extreme prematurity and its outcomes over time. In addition, GDB data have been used to generate hypotheses for prospective studies and to develop new clinical trials by providing information about the numbers and characteristics of available subjects and the expected event rates for conditions and complications to be studied. Since its inception, the GDB has been the basis of more than 200 publications in peer-reviewed journals, many of which have had a significant impact on the field of neonatology.

The critical importance of follow-up to school age: Contributions of the NICHD Neonatal Research Network

Follow-up studies are essential for understanding outcomes and informing the care of infants with high risk for medical and developmental consequences because of extreme prematurity or perinatal illness. Studies that extend to school age often identify sequelae that go unrecognized in neonatal or short-term follow-up studies. Many critical neurocognitive, behavioral, functional, and health outcomes are best assessed beginning at school age. The Eunice Kennedy Shriver National Institute of Child Health and Development Neonatal Research Network (NRN) has performed comprehensive school age evaluations of several key trial cohorts. This manuscript summarizes the important contributions of school age follow-up studies in the NRN, both historically and in ongoing research. We describe in detail the clinical questions that have been answered by the completed studies and new questions about the outcomes of high-risk infants that must be addressed by ongoing and future studies.

Extremfrühgeburt: Schützt Hydrokortison vor einer bronchopulmonalen Dysplasie?

Ein erheblicher Anteil der extrem unreifen Frühgeborenen erleidet eine bronchopulmonale Dysplasie (BPD). Außer der Organunreife, der Beatmung und der Sauerstoffexposition spielen in der Pathogenese inflammatorische Prozesse eine wesentliche Rolle. Ein US-amerikanisches Forscherteam untersuchte nun im Rahmen einer randomisierten kontrollierten Doppelblindstudie, ob Hydrokortison der Lungenkomplikation vorbeugt.

Postnatal Corticosteroids to Prevent or Treat Chronic Lung Disease Following Preterm Birth

The American Academy of Pediatrics continues to provide guidance on the use of postnatal corticosteroids to manage or prevent chronic lung disease following preterm birth (formerly referred to as bronchopulmonary dysplasia). Since the last revision of such guidance in 2010, several prospective randomized trials have been published. This revision provides a review of those studies as well as updated recommendations, which include the use of systemic low-dose corticosteroid in preterm neonates with or at high risk for chronic lung disease. High-dose dexamethasone (≥0.5 mg/kg per day) is not recommended. New evidence suggests that inhaled corticosteroids may confer benefit if provided with surfactant as a vehicle, but safety data are lacking. Evidence remains insufficient to make any recommendations regarding routine use of postnatal corticosteroids in preterm infants. Neonatologists and other hospital care providers must continue to use their clinical judgment in individual patients, balancing the potential adverse effects of corticosteroid treatment with those of chronic lung disease. The decision to use postnatal corticosteroids for this purpose should be made together with the infant's parents, and the care providers should document their discussions with parents in the patient's medical record.