Betamethasone impairs cerebral blood flow velocities in very premature infants with severe chronic lung disease

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.

Prenatal dexamethasone exposure impaired vascular reactivity in adult male offspring cerebral arteries

BACKGROUND

Cerebrovascular disease is one of the leading causes of death worldwide. Middle cerebral artery (MCA) is the largest and most complex of cerebral arteries. The prenatal period is a critical time for development, which largely determines lifelong health. Clinically, glucocorticoids (GCs) administration to accelerate preterm fetal lung maturation has become standard practice. Prenatal GCs administration increases cardiovascular risks in offspring, but little is known regarding the side effects on offspring MCA function.

OBJECTIVE

We investigated the alterations of MCA reactivity following prenatal GCs administration in postnatal offspring.

METHOD AND RESULTS

Pregnant Sprague-Dawley rats received synthetic GCs (dexamethasone, DEX) during the last week of pregnancy, and we examined vascular reactivity, cellular electrophysiology, and gene promoter epigenetic modifications in the male offspring MCA. Our results showed that prenatal DEX exposure increased the sensitivity of offspring MCA to Angiotensin II, which was resulted from the increased Cav1.2 (L-type Ca2+ channels subunit alpha1 C). Mechanistically, prenatal DEX exposure resulted in a transcriptionally active chromatin structure at the Cav1.2 gene promoter by altering histone modifications. This activation led to increased expression of vascular Cav1.2 gene, ultimately resulting in increased MCA contractility in offspring.

CONCLUSION

The present study is the first to demonstrate that the adverse effects of prenatal GCs administration on cerebrovascular tone persist into adulthood, providing new insights into developmental origins of cerebrovascular disease.

Optimizing timing and frequency of head ultrasound screening for severe brain injury among preterm infants born <32 weeks' gestation

OBJECTIVE

To develop a head ultrasound (HUS) screening protocol for infants born <32 weeks gestational age (GA) that accurately identifies severe brain injury (SBI) while minimizing resource use.

STUDY DESIGN

Retrospective cohort study of infants born <32 weeks GA, admitted to a level 3 neonatal intensive care unit between 2011 and 2017. Timing and results of each HUS were reviewed. SBI was defined as intraventricular hemorrhage grade ≥3 and/or periventricular leukomalacia. Logistic regression models were used to identify risk factors and evaluate the predictive value of HUS at different time points during hospitalization.

RESULTS

Of 651 included infants, 71 (11%) developed SBI. Risk factors for SBI were GA at birth <29 weeks (adjusted odds ratio (aOR) 2.87, 95% confidence interval (CI) 1.50-5.48), vasopressors on admission (aOR 3.08, 95%CI 1.38-6.88) and mechanical ventilation on admission (aOR 2.50, 95%CI 1.33-4.68). Infants were classified into three risk groups based on these risk factors, and combinations of 1-5 HUS time points were evaluated to determine the optimal number and timing of HUS for each group. The optimal number of screening HUS ranged from 1 for low-risk to 2 for high-risk infants. Adopting a screening protocol using the number and timing of HUS optimized by risk group could reduce the total number of HUS performed by 40% and the median number of HUS per infant from 3 (IQR 2-4) to 2 (IQR 1-3) (p < .01).

CONCLUSIONS

Implementation of a risk factor-based HUS screening protocol can help reduce resource use while maintaining high sensitivity for detecting SBI.

Recent advances in perinatal neuroprotection

Perinatal brain injury is a major cause of neurological disability in both premature and term infants. In this review, we summarize the evidence behind some established neuroprotective practices such as administration of antenatal steroids, intrapartum magnesium for preterm delivery, and therapeutic hypothermia. In addition, we examine emerging practices such as delayed cord clamping, postnatal magnesium administration, recombinant erythropoietin, and non-steroidal anti-inflammatory agents and finally inform the reader about novel interventions, some of which are currently in trials, such as xenon, melatonin, topiramate, allopurinol, creatine, and autologous cord cell therapy.

Postnatal glucocorticoid-induced hypomyelination, gliosis, and neurologic deficits are dose-dependent, preparation-specific, and reversible

Postnatal glucocorticoids (GCs) are widely used in the prevention of chronic lung disease in premature infants. Their pharmacologic use is associated with neurodevelopmental delay and cerebral palsy. However, the effect of GC dose and preparation (dexamethasone versus betamethasone) on short and long-term neurological outcomes remains undetermined, and the mechanisms of GC-induced brain injury are unclear. We hypothesized that postnatal GC would induce hypomyelination and motor impairment in a preparation- and dose-specific manner, and that GC receptor (GR) inhibition might restore myelination and neurological function in GC-treated animals. Additionally, GC-induced hypomyelination and neurological deficit might be transient. To test our hypotheses, we treated prematurely delivered rabbit pups with high (0.5mg/kg/day) or low (0.2mg/kg/day) doses of dexamethasone or betamethasone. Myelin basic protein (MBP), oligodendrocyte proliferation and maturation, astrocytes, transcriptomic profile, and neurobehavioral functions were evaluated. We found that high-dose GC treatment, but not low-dose, reduced MBP expression and impaired motor function at postnatal day 14. High-dose dexamethasone induced astrogliosis, betamethasone did not. Mifepristone, a GR antagonist, reversed dexamethasone-induced myelination, but not astrogliosis. Both GCs inhibited oligodendrocyte proliferation and maturation. Moreover, high-dose dexamethasone altered genes associated with myelination, cell-cycle, GR, and mitogen-activated protein kinase. Importantly, GC-induced hypomyelination, gliosis, and motor-deficit, observed at day 14, completely recovered by day 21. Hence, high-dose, but not low-dose, postnatal GC causes reversible reductions in myelination and motor functions. GC treatment induces hypomyelination by GR-dependent genomic mechanisms, but astrogliosis by non-genomic mechanisms. GC-induced motor impairment and neurodevelopmental delay might be transient and recover spontaneously in premature infants.

Glucocorticoids promote neural progenitor cell proliferation derived from human induced pluripotent stem cells

Glucocorticoids (GCs) are frequently used for treating and preventing chronic lung disease and circulatory dysfunction in premature infants. However, there is growing concern about the detrimental effects of systemic GC administration on neurodevelopment. The first choice of GCs to minimize the adverse effects on the developing brain is still under debate. We investigated the effect of commonly used GCs such as dexamethasone (DEX), betamethasone (BET) and hydrocortisone (HDC) on the proliferation of human-induced pluripotent stem cell (iPSC)-derived neuronal progenitor cells (NPCs). In this study, NPCs were treated with various concentrations of GCs and subjected to cell proliferation assays. Furthermore, we quantified the number of microtubule-associated protein 2 (MAP2) positive neurons in NPCs by immunostaining. All GCs promoted NPC proliferation in a dose-dependent manner. We also confirmed that MAP2-positive neurons in NPCs increased upon GC treatment. However, differential effects of GCs on MAP2 positive neurons were observed when we treated NPCs with H₂O₂. The total numbers of NPCs increased upon any GC treatment even under oxidative conditions but the numbers of MAP2 positive neurons increased only by HDC treatment. GCs promoted human iPSCs–derived NPC proliferation and the differential effects of GCs became apparent under oxidative stress. Our results may support HDC as the preferred choice over DEX and BET to prevent adverse effects on the developing human brain.

Pathogenesis and prevention of intraventricular hemorrhage

Intraventricular hemorrhage (IVH) is a major neurologic complication of prematurity. Pathogenesis of IVH is attributed to intrinsic fragility of germinal matrix vasculature and to the fluctuation in the cerebral blood flow. Germinal matrix exhibits rapid angiogenesis orchestrating formation of immature vessels. Prenatal glucocorticoid exposure remains the most effective means of preventing IVH. Therapies targeted to enhance the stability of the germinal matrix vasculature and minimize fluctuation in the cerebral blood flow might lead to more effective strategies in preventing IVH.

Postnatal steroids in extremely low birth weight infants: betamethasone or hydrocortisone?

AIM

To compare the efficacy and tolerance of betamethasone (BTM) and hydrocortisone (HC) in weaning extremely low birth weight (ELBW) infants with bronchopulmonary dysplasia (BPD) from the ventilator.

METHODS

Monocentric, retrospective, cohort analysis based on prospective, standardized collection of data between 2005 and 2011 in ELBW receiving postnatal steroids (PS) after the second week of life. We used BTM for the first 4 years, and thereafter HC. We compared extubation rates, growth, glycaemia and blood pressure.

RESULTS

Sixty-seven infants received PS: 35 BTM and 32 HC. Most infants (83% BTM vs. 72% HC) were extubated during treatment (p = 0.281). During PS, the need for insulin was similar. Mean arterial blood pressure was similar at day 3 of PS, but was significantly lower in infants treated by BTM 30 days after the end of treatment. The z-scores for body weight and head circumference indicated significantly greater loss in BTM than HC group. This persisted only for body weight after adjustment for differences in energy intake and corticosteroid dose.

CONCLUSION

Our study suggests that HC may be as efficient as BTM in facilitating the extubation of ELBW infants, without short-term adverse effects. Blood pressure monitoring and investigation of long-term neurodevelopment are nevertheless needed.

Extremely low birthweight infants: how neonatal intensive care unit teams can reduce postnatal malnutrition and prevent growth retardation

AIM

To evaluate the impact of an improved nutritional policy for extremely low birthweight (ELBW) infants on nutritional deficits and postnatal growth.

METHOD

We compared two groups of 37 ELBW infants, born before and after the introduction of an improved nutritional policy in April 2006. Group A (born 2005 to early 2006) and group B (born 2009) stayed in a French neonatal intensive care unit (NICU) for at least 7 weeks. Optimal energy and protein intakes were 120 and 3.5 g/kg/day, respectively, and used to calculate cumulative deficits. Delta z-scores for weight, length and head circumference were calculated between birth and 36 weeks of postmenstrual age (PMA). The improved nutritional policy focused on earlier and higher parenteral intake of lipids and proteins, earlier and higher human milk fortification and earlier transition to preterm formula.

RESULTS

The two groups did not differ in gestational age and birthweight. However, protein and energy deficits were significantly reduced in group B. Between birth and 36 weeks of PMA, delta z-scores were significantly reduced for length (p = 0.012) but not for weight (p = 0.09) or head circumference (p = 0.83).

CONCLUSION

Higher parenteral intake and close attention to enteral feeding reduced nutritional deficits and linear growth restriction in infants admitted to a French NICU.

[The use of postnatal corticosteroid therapy in premature infants to prevent or treat bronchopulmonary dysplasia: current situation and recommendations]

In the last few years, several studies related to the benefit/risk balance of postnatal corticosteroids administered to premature neonates for prevention or treatment of bronchopulmonary dysplasia (BPD) have been published. These data encourage caution, given the risk of long-term adverse neurodevelopmental outcomes. In the meantime, the clinical profile of BPD has been altered based on the progress made in the pre- and postnatal care of premature infants. In 2006, a survey conducted in France in neonatal centers showed that corticosteroids were still frequently used (57% of the centers) following various protocols in very preterm-born infants for respiratory impairment. To promote safer practices and rational use of corticosteroids in the prevention and treatment of BPD in preterm-born neonates, we reviewed the available data in order to establish recommendations. Systemic administration of corticosteroids for prevention or treatment of BPD: (i) should not be used during the first 4 days of life; (ii) is not indicated in the first 3 weeks of life nor (iii) in extubated infants (nasal ventilation or oxygen therapy). The systemic administration of steroids can only be considered after the first 3 weeks of life in very preterm-born ventilator-dependent infants to facilitate extubation (or prevent reintubation related to the severity of BPD). Postnatal dexamethasone administration studied in several randomized clinical trials was shown to have an unfavorable benefit/risk profile, mainly because of the long-term adverse neurocognitive outcomes. Very few studies have been conducted with betamethasone in the postnatal period. According to sparse data, this drug might be as efficacious as dexamethasone, but its long-term risk profile is unknown. It should be noted that following prenatal administration, the benefit/risk profile of betamethasone is better than that of dexamethasone, especially with regard to neurocognitive development. Intravenous hydrocortisone administered at an early stage for the prevention of BPD is being evaluated and should not be administered in this indication, except within clinical trials approved by the ethics committee. No other corticosteroids have been evaluated in the postnatal period in respiratory indications. In conclusion, in the situations described above for which systemic corticosteroids could be justified, the use of betamethasone (or hydrocortisone) appears to be better. As usual, the lowest possible dose of corticosteroids should be administered for the shortest possible duration. The betamethasone-equivalent dose of 0.125 mg/kg/day for 3 days is deemed adequate. If inhaled, corticosteroid therapy may facilitate extubation. Neither its efficacy in respiratory diseases nor its long-term risk profile has been so far established.

Ingestion of bonito extract ameliorates peripheral blood flow in mice loaded from over crowding stress

Bonito extract (BE) has been shown to improve various fatigue-related symptoms. The possibility that the improvement of blood flow contributes to the improvement of fatigue-related symptoms has been reported. However, even though BE has been found to increase peripheral blood flow in humans, an understanding of its mechanisms has remained elusive. The purpose of the present study is to construct an animal model system with which the blood flow-increasing effects of BE can be examined. Using mice loaded with crowding stress, an attempt was made to reproduce the increases in peripheral blood flow observed in humans after a single administration of BE. In this study, the crowded-condition mice (20 mice/cage) showed significantly increased catecholamine levels (noradrenaline, adrenaline, and dopamine) in their circulating blood and a decreased rate of skin blood perfusion in comparison with the normal-condition mice (6 mice/cage). The rate of skin blood perfusion was significantly increased by BE in the crowded-condition mice in comparison with the controls, but not influenced by BE in the normal-condition mice. This suggests that BE expands the vascular diameter by affecting the constriction of vessels induced by catecholamines.

Postnatal betamethasone vs dexamethasone in premature infants with bronchopulmonary dysplasia: a pilot study

OBJECTIVE

As effects of glucocorticoids differ with respect to preparation, dose and duration, we hypothesized that a postnatal regimen of a low-dose, short-course betamethasone treatment had comparable efficacy and a better safety profile compared to the conventional high-dose, dexamethasone.

STUDY DESIGN

To test our hypothesis, we selected premature neonates with a birth weight <or=1000 g and a gestational age <or=29 weeks who were ventilated >10 postnatal days with an FiO(2)>0.4 and no ability to wean mechanical support for >or=3 consecutive days. These neonates either received twice daily dexamethasone 0.25 mg kg(-1) per dose intravenously for 3 days tapered to 0.125 mg kg(-1) per dose for 4 days (June 1999 to December 2000) or betamethasone 0.125 mg kg(-1) per day intramuscularly once per day for 3 days (January 2001 to December 2002).

RESULT

We found a significant reduction in FiO(2) after 3 days in both glucocorticoid treatment groups. There were no significant differences between the two treatment groups in the clinical parameters including decrease in FiO(2), oxygenation index, mean airway pressure and percent extubation. Duration of ventilation, number of oxygen days and length of hospital stay were comparable in the two groups. Of particular interest, the betamethasone group showed fewer adverse effects, such as poor weight gain and high blood glucose, than the dexamethasone group.

CONCLUSION

A short course of low-dose betamethasone has comparable efficacy and seemingly a better short-term safety profile compared to conventional dexamethasone treatment.

Current controversies in perinatal steroid therapy

Few therapies in perinatal medicine have created as much controversy as corticosteroids. Despite five decades of extensive research and practice, major areas of uncertainty remain. In this article, we review the most current evidence on both antenatal and postnatal therapy.

CONCLUSION

Overall, it is clear that we must continue to investigate the most appropriate doses of the ideal preparation in the most appropriate target populations before we can let the steroid issues rest.