Glucocorticoid Metabolism in the Human Fetal Lung: Implications for Lung Development and the Pulmonary Surfactant System

Pulmonary interstitial glycogenosis in two neonates: Early recognition and use of corticosteroids

Pulmonary interstitial glycogenosis (PIG) is known to be associated with a wide variety of congenital conditions, though the extent to which PIG contributes to clinical presentation and outcomes in infants remains controversial. We describe two cases of infants with congenital anomalies and respiratory distress at birth who were diagnosed with PIG with differing clinical courses and response to methylprednisolone therapy. These cases highlight the importance of improved recognition of PIG and uncertainties about which patients may benefit from treatment.

Expression and function of mitochondrial inhibitor factor-1 and TASK channels in adrenal cells

Adrenal medullary chromaffin (AMC) cells in the perinatal period and carotid body glomus cells after birth respond to hypoxia with catecholamine secretion. The hypoxia detection mechanism in such O2-sensitive cells is still not well defined. One hypothesis is that a decrease in cellular ATP may be involved in the hypoxia detection. This idea is based on ATP dependence of TASK channel activity that regulates the resting membrane potential and is suppressed by hypoxia in glomus cells. Mitochondrial ATPase inhibitor factor-1 (IF1), a physiological regulator of ATP synthase, helps prevent ATP hydrolysis under hypoxic conditions. In cells where IF1 expression is high, exposure to hypoxia is expected to have no effect on TASK channel activity. This possibility was electrophysiologically and immunocytochemically explored. Single channel recordings revealed that 36-pS TASK3-like channels contribute to the resting membrane potential in young rat adrenal cortical (AC) cells. TASK3-like channel activity in a cell-attached patch was not affected by bath application of mitochondrial inhibitors. Consistent with this finding, IF1-like immunoreactive material was well expressed in rat AC cells. In further support of our hypothesis, IF1-like immunoreactive material was well expressed in adult rat AMC cells that are known to be hypoxia-insensitive and minimally expressed in newborn AMC cells that are hypoxia-sensitive. These results provide evidence for the functional relevance of IF1 expression in excitability in O2-sensitive cells in response to mitochondrial inhibition.

Urinary Proteome Changes during Pregnancy in Rats

Pregnancy involves a significant number of physiological changes. A normal pregnancy is essential to ensure healthy maternal and fetal development. We sought to explore whether the urinary proteome could reflect the pregnancy process. Urine samples were collected from pregnant and control rats on various gestational days. The urinary proteome was profiled by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), and differential proteins were obtained by comparing to the gestational day 1 of the same group at each time point. Many pathways related to embryo implantation and trophoblast differentiation were enriched in the early days in urine. Liver, kidney, and bone development started early to be enriched in the pregnant group, but not in the control group. Interestingly, the developmental processes of the fetal heart such as heart looping and endocardial cushion formation could be seen in urine of pregnant rats. Moreover, the timings were consistent with those of embryological studies. The timing of the surfactant appearance in urine was right before birth. The differential proteins related to pancreas development appeared in urine at the time during reported time of pancreatic cell proliferation and differentiation. These processes were enriched only in the pregnant group and not in the control group. Furthermore, coagulation-associated pathways were found to be increasingly prominent before labor. Our results indicated that the urine proteome of pregnant rats can reflect the process of pregnancy, even fetal embryonic development. Maternal urinary proteome detection was earlier than the developmental time point of tissue sections observed by microscopy.

Pulmonary hypertension in the newborn- etiology and pathogenesis

A disruption in the well-orchestrated fetal-to-neonatal cardiopulmonary transition at birth results in the clinical conundrum of severe hypoxemic respiratory failure associated with elevated pulmonary vascular resistance (PVR), referred to as persistent pulmonary hypertension of the newborn (PPHN). In the past three decades, the advent of surfactant, newer modalities of ventilation, inhaled nitric oxide, other pulmonary vasodilators, and finally extracorporeal membrane oxygenation (ECMO) have made giant strides in improving the outcomes of infants with PPHN. However, death or the need for ECMO occurs in 10-20% of term infants with PPHN. Better understanding of the etiopathogenesis of PPHN can lead to physiology-driven management strategies. This manuscript reviews the fetal circulation, cardiopulmonary transition at birth, etiology, and pathophysiology of PPHN.

Protocol for a Cross-Sectional Study: Effects of a Multiple Sclerosis Relapse Therapy With Methylprednisolone on Offspring Neurocognitive Development and Behavior (MS-Children)

Introduction

Multiple Sclerosis (MS) is the most common neuroimmunological disease in women of childbearing age. Current MS therapy consists of immunomodulatory relapse prevention with disease-modifying therapies (DMTs) and acute relapse therapy with the synthetic glucocorticoid (GC) methylprednisolone (MP). As most DMTs are not approved for use during pregnancy, treatment is usually discontinued, increasing the risk for relapses. While MP therapy during pregnancy is considered relatively save for the fetus, it may be detrimental for later cognitive and neuropsychiatric function. The underlying mechanism is thought to be an epigenetically mediated desensitization of GC receptors, the subsequent increase in stress sensitivity, and a GC-mediated impairment of brain development. The aim of this study is to investigate the associations of fetal MP exposure in the context of MS relapse therapy with later cognitive function, brain development, stress sensitivity, and behavior.

Methods and Analysis

Eighty children aged 8–18 years of mothers with MS will be recruited. Forty children, exposed to GC in utero will be compared to 40 children without fetal GC exposure. The intelligence quotient will serve as primary outcome. Secondary outcomes will include attention, motor development, emotional excitability, Attention-Deficit Hyperactivity Disorder-related symptoms, and behavioral difficulties. The Trier Social Stress Test will test stress sensitivity, EEG and MRI will assess functional and structural brain development. To determine underlying mechanisms, DNA methylation of the GC receptor gene and the H19/IGF2 locus and changes in the microbiome and the metabolome will be investigated. Primary and secondary outcomes will be analyzed using linear regression models. Time-variant outcomes of the stress test will be analyzed in two mixed linear models exploring overall activity and change from baseline.

Ethics and Dissemination

This study was approved by the participating institutions' ethics committees and results will be presented in accordance with the STROBE 2007 Statement.

Trial Registration

https://clinicaltrials.gov/ct2/show/NCT04832269?id=ZKSJ0130

A Growing Dilemma: Antenatal Corticosteroids and Long-Term Consequences

OBJECTIVE

A single course of synthetic antenatal corticosteroids is standard care for women considered to be at risk for preterm birth before 34 weeks of gestation. While the intended target is the fetal lung, the fetal brain contains remarkably high levels of glucocorticoid receptors in structures critical in the regulation of behavior and endocrine function. Negative programming signals may occur which can lead to permanent maladaptive changes and predispose the infant/child to an increased risk in physical, mental, and developmental disorders.

METHODS

Framed around these areas of concerns for physical, mental, and developmental disorders, this narrative review drew on studies (animal and clinical), evaluating the long-term effects of antenatal corticosteroids to present the case that a more targeted approach to the use of antenatal corticosteroids for the betterment of the fetus urgently needed.

RESULTS

Studies raised concerns about the potential negative long-term consequences, especially for the exposed fetus who was born beyond the period of the greatest benefit from antenatal corticosteroids. The long-term consequences are more subtle in nature and usually manifest later in life, often beyond the scope of most clinical trials.

CONCLUSION

Continued research is needed to identify sufficient safety data, both short term and long term. Caution in the use of antenatal corticosteroids should be exercised while additional work is undertaken to optimize dosing strategies and better identify women at risk of preterm birth prior to administration of antenatal corticosteroids.

KEY POINTS

· A single-course ACS is a remarkable therapy with substantial benefits.. · There is a potential of long-term neurodevelopmental consequences in the ACS-exposed fetus.. · There is a need to improve dosing strategies and identification of appropriate at risk women..

Inhaled Budesonide in Neonatal Respiratory Distress Syndrome of Near-Term Neonates: A Randomized, Placebo-Controlled Trial

OBJECTIVE

This study evaluates the value of inhaled budesonide (BUD) administration in neonatal respiratory distress syndrome (RDS) cases especially for near-term neonates.

METHODS

A randomized controlled trial involving 120 neonates with respiratory distress, which was diagnosed as RDS, was conducted from July 2016 to March 2018. The neonates studied were divided into 2 groups: group 1 (the inhaled BUD group), consisting of 60 neonates who received BUD (2 mL, 0.25-mg/mL suspension) inhalation, twice daily for 5 days; and group 2 (the placebo group), consisting of 60 neonates with RDS who received humidified distilled sterile water inhalation (2 mL). Downes score, RDS grades, and interleukin 8 (IL-8) levels were monitored and measured on the first and fifth days of incubation.

RESULTS

Statistically significant differences (SSDs) in RDS grades, Downes score, and IL-8 levels on the fifth day of admission were observed between groups 1 and 2 (p = 0.001) and between the first and fifth days of incubation in group 1 (p = 0.001). The SSDs in the duration of hospitalization (p = 0.001) and the number of neonates receiving mechanical ventilation (p = 0.032) were found between both groups.

CONCLUSIONS

Budesonide inhalation is associated with improvements in clinical and laboratory parameters in neonates with RDS.

Decreased 11β-hydroxysteroid dehydrogenase 1 in lungs of steroid receptor coactivator (Src)-1/-2 double-deficient fetal mice is caused by impaired glucocorticoid and cytokine signaling

Our previous research revealed that steroid receptor coactivators (Src)-1 and -2 serve a critical cooperative role in production of parturition signals, surfactant protein A and platelet-activating factor, by the developing mouse fetal lung (MFL). To identify the global landscape of genes in MFL affected by Src-1/-2 double-deficiency, we conducted RNA-seq analysis of lungs from 18.5 days post-coitum (dpc) Src-1^-/- /-2^-/- (dKO) vs. WT fetuses. One of the genes most highly downregulated (~4.8 fold) in Src-1/-2 dKO fetal lungs encodes 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), which catalyzes conversion of inactive 11-dehydrocorticosterone to the glucocorticoid receptor (GR) ligand, corticosterone. Glucocorticoids were reported to upregulate 11β-HSD1 expression in various cell types via induction of C/EBP transcription factors. We observed that C/ebpα and C/ebpβ mRNA and protein were markedly reduced in Src-1/-2 double-deficient (Src-1/-2^d/d ) fetal lungs, compared to WT. Moreover, glucocorticoid induction of 11β-hsd1, C/ebpα and C/ebpβ in cultured MFL epithelial cells was prevented by the SRC family inhibitor, SI-2. Cytokines also contribute to the induction of 11β-HSD1. Expression of IL-1β and TNFα, which dramatically increased toward term in lungs of WT fetuses, was markedly reduced in Src-1/-2^d/d fetal lungs. Our collective findings suggest that impaired lung development and surfactant synthesis in Src-1/-2^d/d fetuses are likely caused, in part, by decreased GR and cytokine induction of C/EBP and NF-κB transcription factors. This results in reduced 11β-HSD1 expression and glucocorticoid signaling within the fetal lung, causing a break in the glucocorticoid-induced positive feedforward loop.

Rapid biophysical analyses of gastric aspirates from risk newborns for lung maturity assessment after corticosteroid therapy

BACKGROUND

One of the main causes for the higher mortality among risk newborn children (including preterm infants) is neonatal respiratory distress syndrome (NRDS), which develops as a result of primary deficiency or secondary inactivation of alveolar surfactant (AS). Therefore, fast and early diagnostics of risk newborns lung maturity is crucial for their prompt therapy.

MATERIALS AND METHODS

Gastric aspirates (GA) were collected from 77 infants divided into three groups: a control of 38 healthy full-term infants; 16 prematurely newborns with NRDS, and 23 prematurely born infants after in vitro fertilization and corticosteroid therapy (CST). Surface parameters: equilibrium (γeq), maximal (γmax) and minimal (γmin) surface tension, and the shape of hysteresis curves of GA monolayers were measured by axisymmetric drop shape analysis (ADSA) of a pending drop. In addition, the morphology of GA monolayers was studied by Brewster angle microscopy (BAM).

RESULTS

Our results showed that only γmin values were reliable and were significantly lower in full-term infants, as compared to the risk neonates. The results obtained were proved by the shape of hysteresis curves of GA surface active films. BAM images of GA monolayers from NRDS group showed impaired surface morphology due to the surfactant insufficiency, as compared to the control group. Corticosteroid therapy improved both GA surface characteristics and monolayer morphology.

CONCLUSIONS

GAs analyses by ADSA and BAM are fast and informative approaches for lung maturity assessment. In addition, the corticosteroid therapy applied improved all GAs surface parameters due to AS maturation.

Social buffering of the maternal and infant HPA axes: Mediation and moderation in the intergenerational transmission of adverse childhood experiences

Supportive social relationships can reduce both psychological and physiological responses to stressful experiences. Recently, studies have also assessed the potential for social relationships to buffer the intergenerational transmission of stress. The majority of these studies, however, have focussed on social learning as a mechanism responsible for the intergenerational transmission of stress. Evidence of biological mechanisms is lacking. The objective of the current study was, therefore, to determine whether the association between maternal adverse childhood experiences (ACEs) and infant hypothalamic-pituitary-adrenal (HPA) axis function is mediated by maternal HPA axis function during pregnancy and moderated by social support. Data were from 243 mother-infant dyads enrolled in a prospective longitudinal cohort (the Alberta Pregnancy Outcomes and Nutrition Study). Maternal history of ACEs was retrospectively assessed while maternal perceived social support and salivary cortisol were assessed prospectively at 6-22 weeks gestation (Time 1) and 27-37 weeks gestation (Time 2), and infant cortisol reactivity to a laboratory stressor and maternal perceived social support were assessed at 5-10 months postnatal (Time 3). Results revealed that maternal HPA axis function during pregnancy mediated the effects of maternal ACEs on infant HPA axis reactivity, suggesting that the maternal HPA axis is a mechanism by which maternal early life stress is transmitted to offspring. Furthermore, social support in the prenatal and postnatal periods moderated the cascade from maternal ACEs to infant HPA axis reactivity. Specifically, prenatal social support moderated the association between ACEs and maternal HPA axis function during pregnancy, and postnatal social support moderated the association between maternal HPA axis function and infant cortisol reactivity. These findings highlight the social sensitivity of the HPA axis and suggest the utility of social relationships as an intervention target to reduce the effects of maternal early life stress on infant outcomes.

Normalisation of surfactant protein -A and -B expression in the lungs of low birth weight lambs by 21 days old

Intrauterine growth restriction (IUGR) induced by placental restriction (PR) in the sheep negatively impacts lung and pulmonary surfactant development during fetal life. Using a sheep model of low birth weight (LBW), we found that there was an increase in mRNA expression of surfactant protein (SP)-A, -B and -C in the lung of LBW lambs but no difference in the protein expression of SP-A or -B. LBW also resulted in increased lysosome-associated membrane glycoprotein (LAMP)-3 mRNA expression, which may indicate an increase in either the density of type II Alveolar epithelial cells (AEC) or maturity of type II AECs. Although there was an increase in glucocorticoid receptor (GR) and 11β-hydroxysteroid dehydrogenase (11βHSD)-1 mRNA expression in the lung of LBW lambs, we found no change in the protein expression of these factors, suggesting that the increase in SP mRNA expression is not mediated by increased GC signalling in the lung. The increase in SP mRNA expression may, in part, be mediated by persistent alterations in hypoxia signalling as there was an increase in lung HIF-2α mRNA expression in the LBW lamb. The changes in the hypoxia signalling pathway that persist within the lung after birth may be involved in maintaining SP production in the LBW lamb.

CYP21A2 expression is localized in the developing distal epithelium of the human perinatal lung and is compatible with in situ production and intracrine actions of active glucocorticoids

Glucocorticoids play essential roles in lung development. We investigated for expression of CYP21A2 (21-hydroxylase) as well as for the presence of the corresponding protein and identification of CYP21A2-expressing cells in several human developing lungs. Expression of some related genes was also assessed. CYP21A2 and CYP17A1 (P450c17) mRNAs were found in all the 34 lung samples from 17 to 40 weeks' gestation at variable levels. No correlation was found according to sex but a correlation with age was detected for CYP17A1 only. In contrast, CYP11B1 (11β-hydroxylase)- and CYP11B2 (aldosterone synthase)-mRNAs were not detected. Significant levels of the CYP21A2 protein were detected in all the analyzed samples, while only very low signals were detected for CYP17A1 protein. In situ hybridization revealed that CYP21A2 was almost exclusively expressed in the distal epithelium. It was reported that the lung distal epithelium of human fetuses also express 11β-hydroxysteroid dehydrogenase type 2, which catalyzes cortisol inactivation into cortisone. Based on this information, intracrine glucocorticoid actions should take place from CYP21A2 products through the glucocorticoid receptor in the absence of cortisol. In contrast, mineralocorticoid receptor activation did not seem to depend on deoxycorticosterone produced from local activity of CYP21A2 because of the reported circulating amounts of aldosterone.

The clinical use of corticosteroids in pregnancy

BACKGROUND

The use of antenatal steroid therapy is common in pregnancy. In early pregnancy, steroids may be used in women for the treatment of recurrent miscarriage or fetal abnormalities such as congenital adrenal hyperplasia. In mid-late pregnancy, the antenatal administration of corticosteroids to expectant mothers in anticipation of preterm birth is one of the most important advances in perinatal medicine; antenatal corticosteroids are now standard care for pregnancies at risk of premature delivery in high- and middle-income countries. The widespread uptake of this therapy is due to a compelling body of evidence demonstrating improved neonatal outcomes following antenatal corticosteroid exposure, stemming most notably from corticosteroid-driven maturation of fetal pulmonary function. As we approach the 50th anniversary of landmark work in this area by Liggins and Howie, it is apparent that much remains to be understood with regards to how we might best apply antenatal corticosteroid therapy to improve pregnancy outcomes at both early and mid to late gestation.

METHODS

Drawing on advances in laboratory science, pre-clinical and clinical studies, we performed a narrative review of the scientific literature to provide a timely update on the benefits, risks and uncertainties regarding antenatal corticosteroid use in pregnancy. Three, well-established therapeutic uses of antenatal steroids, namely recurrent miscarriage, congenital adrenal hyperplasia and preterm birth, were selected to frame the review.

RESULTS

Even the most well-established antenatal steroid therapies lack the comprehensive pharmacokinetic and dose-response data necessary to optimize dosing regimens. New insights into complex, tissue-specific corticosteroid signalling by genomic-dependent and independent mechanisms have not been used to inform corticosteroid treatment strategies. There is growing evidence that some fetal corticosteroid treatments are either ineffective, or may result in adverse outcomes, in addition to lasting epigenetic changes in a variety of homeostatic mechanisms. Nowhere is the need to better understand the intricacies of corticosteroid therapy better conveyed than in the findings of Althabe and colleagues who recently reported an increase in overall neonatal mortality and maternal morbidity in association with antenatal corticosteroid administration in low-resource settings.

CONCLUSIONS

New research to clarify the benefits and potential risks of antenatal corticosteroid therapy is urgently needed, especially with regard to corticosteroid use in low-resource environments. We conclude that there is both significant scope and an urgent need for further research-informed refinement to the use of antenatal corticosteroids in pregnancy.

Intergenerational transmission of the effects of acculturation on health in Hispanic Americans: a fetal programming perspective

We propose a transdisciplinary, life span framework for examining the underlying cause of the observed intergenerational decline in health among Hispanic Americans. We focus on acculturation, and we posit that acculturation-related processes in first-generation Hispanic immigrant mothers may affect the intrauterine development of an unborn child, via the process of fetal programming, to produce phenotypic effects that may alter the susceptibility for noncommunicable chronic diseases. In this manner, an intergenerational cascade of perpetuation may become established. Our framework may shed light on the biological, behavioral, and social causes of intergenerational cycles of vulnerability among immigrant minority groups, with public health and policy implications for primary prevention and intervention.

Transition from fetus to newborn

The fetus to newborn transition is a complex physiologic process that requires close monitoring. Approximately 10% of all newborns require some support in facilitating a successful transition after delivery. Clinicians should be aware of the physiologic processes and pay close regard to the newborn's cardiopulmonary transition at birth to provide appropriate treatment and therapies as required. Trained Personnel in the Neonatal Resuscitation program should be available at the delivery for all newborns to ensure that immediate and appropriate care is provided to achieve the best possible outcomes for those babies not smoothly transitioning to extrauterine life.

Glucocorticoid metabolism in the developing lung: adrenal-like synthesis pathway

Glucocorticoids (GCs) are essential to normal lung development. They participate in the regulation of important developmental events including morphological changes, and lung maturation leading to the surge of surfactant synthesis by type II epithelial cells. Antenatal GC is administered to mothers at risk of premature delivery to reduce the risk of respiratory distress syndrome (RDS). Sex differences were reported in RDS, in the efficiency of antenatal GC treatment independently of surfactant levels, and in surfactant lipid synthesis. Type II epithelial cell maturation is regulated by epithelial-fibroblast cell-cell communication and involves paracrine factors secreted by fibroblasts under the stimulatory effect of GC. This positive action of GC can be inhibited by androgens through the androgen receptor (AR) present in fibroblasts. In fact, lung development is regulated not only by GC and androgens but also by GC and androgen metabolisms within the developing lung. We recently reviewed the metabolism of androgens in the fetal lung [45]. Here, we review multiple aspects of GC metabolism in the developing lung including inactivation and re-activation by 11β-HSDs, synthesis from the adrenal-like synthesis pathway expressed within the lung and the putative role of CRH and ACTH originating from lung in the regulation of this pathway. This article is part of a Special Issue entitled 'Pregnancy and Steroids'.

Leptin promotes fetal lung maturity and upregulates SP-A expression in pulmonary alveoli type-II epithelial cells involving TTF-1 activation

The placental hormone leptin has important functions in fetal and neonatal growth, and prevents depressed respiration in leptin-deficient mice. The effect of leptin on respiratory distress suffered by low birth weight and premature infants has been studied. However, it is unclear how leptin enhances lung maturity in the fetus and ameliorates neonatal respiratory distress. In the present study, we found that antenatal treatment with leptin for 2 d significantly enhanced the relative alveolus area and improved the maturity of fetal lungs in a rat model of fetal growth restriction (FGR). Mean birth weight and lung wet weight were higher in the leptin-treated group than in the PBS-treated group, indicating promotion of fetal growth. Leptin upregulated the intracellular expression and extracellular secretion of surfactant protein (SP) A in type-II alveolar epithelial cells (AECs) in vivo and in vitro. Dual positive effects of leptin were found on protein expression and transcriptional activity of thyroid transcription factor-1 (TTF-1), a nuclear transcription essential for branching morphogenesis of the lung and expression of SP-A in type-II AECs. Knockdown of TTF-1 by RNA interference indicated that TTF-1 may play a vital role in leptin-induced SP-A expression. These results suggest that leptin may have great therapeutic potential for the treatment of FGR, and leptin-mediated SP-A induction and lung maturity of the fetus are TTF-1 dependent.

Ultra-high dose of intra-amniotic or direct fetal intramuscular betamethasone for lung maturation in the preterm goat model

OBJECTIVE

To evaluate the effects of intra-amniotic (IA) and fetal injections of a single ultra-high dose of betamethasone (BM) 48 h before preterm delivery on neonatal pulmonary function, using an experimental goat model.

STUDY DESIGN

Eighteen date-mated singleton pregnant Hair goats were randomized into four groups. At gestational day 118 (alveolar phase, term 150-155 days) after obtaining a sample of amniotic fluid, fetuses in group 1 (n=5) received 8 mg/kg IA BM, and in group 2 (n=5) 4 mg/kg fetal IM BM. In group 3 (n=4) (0.3mg/kg/day) maternal BM was administered at day 118 and 119 with a 24h interval; control fetuses (n=4) received 1 mL/kg of IA saline at day 118. At gestational day 120, after obtaining second sample of amniotic fluids 18 kids were delivered by preterm cesarean section, entubated, weighed, and mechanically ventilated for 15 min. Arterial blood gas samples and deflation/inflation lung pressure-volume measurements were obtained. After sacrifice, lungs were removed, weighed, gross examined and processed for further histological and immunohistochemical (IHC) evaluations. On hematoxylin and eosin (HE) stained slides, presence and severity of lung emphysema was evaluated; slides stained for surfactant proteins, and caspases were used for semi-quantitative evaluation of lung maturation. Kruskal-Wallis, Mann-Whitney, Wilcoxon signed rank, and chi-square tests were used for comparisons.

RESULTS

IA BM was associated with increased number of stillbirths (60% vs. 0% in control) (p=0.06) and emphysematous changes. Bodyweight-adjusted pressure-volume measurements were improved after maternal, but not IA or fetal, BM (p=0.06). Following mechanical ventilation, arterial blood gas parameters did not significantly alter across maternal and fetal administrations. However, pH was significantly lower (p<0.05) and carbon dioxide partial pressure was higher (p<0.05) in the control group, indicating hypercapnic acidemia in non-treated pregnancies. None of the treatments induced measurable alterations in amniotic fluid lecithin/sphingomyelin (L/S) values. IA and fetal routes were associated with decreased surfactant protein expressions and increased apoptotic activity in alveolar and bronchio-alveolar epithelial cells.

CONCLUSION

Ultra-high dose IA and fetal IM BM is not superior to the standard dose and maternal way of administration in our experimental design.

Fetal programming of body composition, obesity, and metabolic function: the role of intrauterine stress and stress biology

Epidemiological, clinical, physiological, cellular, and molecular evidence suggests that the origins of obesity and metabolic dysfunction can be traced back to intrauterine life and supports an important role for maternal nutrition prior to and during gestation in fetal programming. The elucidation of underlying mechanisms is an area of interest and intense investigation. In this perspectives paper we propose that in addition to maternal nutrition-related processes it may be important to concurrently consider the potential role of intrauterine stress and stress biology. We frame our arguments in the larger context of an evolutionary-developmental perspective that supports roles for both nutrition and stress as key environmental conditions driving natural selection and developmental plasticity. We suggest that intrauterine stress exposure may interact with the nutritional milieu, and that stress biology may represent an underlying mechanism mediating the effects of diverse intrauterine perturbations, including but not limited to maternal nutritional insults (undernutrition and overnutrition), on brain and peripheral targets of programming of body composition, energy balance homeostasis, and metabolic function. We discuss putative maternal-placental-fetal endocrine and immune/inflammatory candidate mechanisms that may underlie the long-term effects of intrauterine stress. We conclude with a commentary of the implications for future research and clinical practice.

Natural variation in gestational cortisol is associated with patterns of growth in marmoset monkeys (Callithrix geoffroyi)

High levels of prenatal cortisol have been previously reported to retard fetal growth. Although cortisol plays a pivotal role in prenatal maturation, heightened exposure to cortisol can result in lower body weights at birth, which have been shown to be associated with adult diseases like hypertension and cardiovascular disease. This study examines the relationship between natural variation in gestational cortisol and fetal and postnatal growth in marmoset monkeys. Urinary samples obtained during the mother's gestation were analyzed for cortisol. Marmoset body mass index (BMI) was measured from birth through 540 days in 30- or 60-day intervals. Multi-level modeling was used to test if marmoset growth over time was predicted by changes in gestational cortisol controlling for time, sex, litter, and litter size. The results show that offspring exposed to intra-uterine environments with elevated levels of cortisol had lower linear BMI rates of change shortly after birth than did offspring exposed to lower levels of cortisol, but exhibited a higher curvilinear growth rate during adolescence. Average daily change in gestational cortisol during the first trimester had a stronger relationship with postnatal growth than change during the third trimester. Higher exposure to cortisol during gestation does alter developmental trajectories, however there appears to be a catch-up period during later post-natal growth. These observations contribute to a larger discussion about the relationship of maternal glucocorticoids on offspring development and the possibility of an earlier vulnerable developmental window.

Variations in CRHR1 are associated with persistent pulmonary hypertension of the newborn

INTRODUCTION

Persistent pulmonary hypertension of the newborn (PPHN) is associated with substantial infant morbidity and mortality. Recently, genetic associations have been found in idiopathic pulmonary arterial hypertension.

RESULTS

PPHN was significantly (P < 0.05) associated with genetic variants in corticotropin-releasing hormone (CRH) receptor 1, CRHR1 and CRH-binding protein, CRHBP. Association with CRHR1 rs4458044 passed the Bonferroni threshold for significance. No mutations were found in the bone morphogenetic protein receptor type II (BMPR2) gene.

DISCUSSION

We describe previously unreported genetic associations between PPHN and CRHR1 and CRHBP. These findings may have implications for further understanding the pathophysiology of PPHN and treatment.

METHODS

We performed a family-based candidate gene study to examine a genetic association with PPHN and sequenced the BMPR2 gene in 72 individuals. We enrolled 110 families with infants diagnosed with PPHN based on inclusion criteria. After medical chart review, 22 subjects were excluded based on predefined criteria, and DNA samples from 88 affected infants and at least one parent per infant were collected and genotyped. Thirty-two single-nucleotide polymorphisms in 12 genes involved in vasoconstriction/vasodilation, lung development, surfactant regulation, or vascular endothelial cell function were investigated using family-based association tests.

Development and function of the human fetal adrenal cortex: a key component in the feto-placental unit

Continuous efforts have been devoted to unraveling the biophysiology and development of the human fetal adrenal cortex, which is structurally and functionally unique from other species. It plays a pivotal role, mainly through steroidogenesis, in the regulation of intrauterine homeostasis and in fetal development and maturation. The steroidogenic activity is characterized by early transient cortisol biosynthesis, followed by its suppressed synthesis until late gestation, and extensive production of dehydroepiandrosterone and its sulfate, precursors of placental estrogen, during most of gestation. The gland rapidly grows through processes including cell proliferation and angiogenesis at the gland periphery, cellular migration, hypertrophy, and apoptosis. Recent studies employing modern technologies such as gene expression profiling and laser capture microdissection have revealed that development and/or function of the fetal adrenal cortex may be regulated by a panoply of molecules, including transcription factors, extracellular matrix components, locally produced growth factors, and placenta-derived CRH, in addition to the primary regulator, fetal pituitary ACTH. The role of the fetal adrenal cortex in human pregnancy and parturition appears highly complex, probably due to redundant and compensatory mechanisms regulating these events. Mounting evidence indicates that actions of hormones operating in the human feto-placental unit are likely mediated by mechanisms including target tissue responsiveness, local metabolism, and bioavailability, rather than changes only in circulating levels. Comprehensive study of such molecular mechanisms and the newly identified factors implicated in adrenal development should help crystallize our understanding of the development and physiology of the human fetal adrenal cortex.

Prenatal stress and developmental programming of human health and disease risk: concepts and integration of empirical findings

PURPOSE OF REVIEW

The concept of the developmental origins of health and disease susceptibility is rapidly attracting interest and gaining prominence as a complementary approach to understanding the causation of many complex common disorders that confer a major burden of disease; however several important issues and questions remain to be addressed, particularly in the context of humans.

RECENT FINDINGS

In this review we enunciate some of these questions and issues, review empirical evidence primarily from our own recent studies on prenatal stress and stress biology, and discuss putative maternal-placental-fetal endocrine and immune/inflammatory candidate mechanisms that may underlie and mediate short-term and long-term effects of prenatal stress on the developing human embryo and fetus, with a specific focus on body composition, metabolic function, and obesity risk.

SUMMARY

The implications for research and clinical practice are discussed with a summary of recent advances in noninvasive methods to characterize fetal, newborn, infant, and child developmental and health-related processes that, when coupled with available state-of-the-art statistical modeling approaches for longitudinal, repeated measures time series analysis, now afford unprecedented opportunities to explore and uncover the developmental origins of human health and disease.

Prenatal stress and brain development

Prenatal stress (PS) has been linked to abnormal cognitive, behavioral and psychosocial outcomes in both animals and humans. Animal studies have clearly demonstrated PS effects on the offspring's brain, however, while it has been speculated that PS most likely affects the brains of exposed human fetuses as well, no study has to date examined this possibility prospectively using an independent stressor (i.e., a stressful event that the pregnant woman has no control over, such as a natural disaster). The aim of this review is to summarize the existing animal literature by focusing on specific brain regions that have been shown to be affected by PS both macroscopically and microscopically. These regions include the hippocampus, amygdala, corpus callosum, anterior commissure, cerebral cortex, cerebellum and hypothalamus. We first discuss the mechanisms by which the effects of PS might occur. In particular, we show that maternal and fetal hypothalamic-pituitary-adrenal (HPA) axes, and the placenta, are the most likely candidates for these mechanisms. We see that, although animal studies have obvious advantages over human studies, the integration of findings in animals and the transfer of these findings to human populations remains a complex issue. Finally, we show how it is possible to circumvent these challenges by studying the effects of PS on brain development directly in humans, by taking advantage of natural or man-made disasters and assessing the impact and consequences of such stressful events on pregnant women and their offspring prospectively.

Antenatal steroids and antioxidant enzyme activity in preterm infants: influence of gender and timing

Antenatal steroids have improved the survival of preterm infants; however, the mechanism of action is not fully understood. We aimed to establish an association between antenatal steroids and antioxidant activity and postnatal oxidative stress. In a prospective cohort study, extremely preterm neonates receiving antenatal steroids (CORT) or not (NOCORT) were enrolled. An association between antenatal steroids and activities of antioxidant enzymes and glutathione cycle enzymes in cord blood was found. In addition, reduced oxidative stress (GSH/GSSG ratio, CORT vs. NOCORT, 35.68 + or - 12.20 vs. 28.38 + or - 9.92; p < 0.01) and, decreased oxidation of proteins (ortho-tyrosine/phenylalanine ratio, CORT vs. NOCORT, 8.66 + or - 2.45 vs. 12.55 + or - 4.41; p < 0.01) and DNA (8oxodG/2dG ratio, CORT vs. NOCORT, 6.73 + or - 2.18 vs. 9.53 + or - 3.83; p < 0.01) also was found. Antenatal steroids were associated with reduced oxygen supplementation, mechanical ventilation, and conditions such as bronchopulmonary dysplasia, intra-periventricular hemorrhage, or retinopathy of prematurity. The maximal effectiveness was when steroids were administered 2-4 days before delivery. Female preterm infants had less oxidative stress and increased antioxidant activity and better clinical outcomes than did male infants, independent of receiving or not antenatal steroids. Antenatal steroids are accompanied by a reduction in postnatal oxidative-stress-derived conditions and increased antioxidant enzyme activity. Both these effects seem to be influenced by specific timing and female gender.

Histologic resolution of pulmonary interstitial glycogenosis

Pulmonary interstitial glycogenosis (PIG) is an enigmatic lung disorder of unknown etiology that presents with neonatal respiratory distress. Despite its dramatic clinical presentation, the diagnosis of PIG has a favorable prognosis with rare mortality in the absence of comorbid conditions. In this report, we describe changes in successive lung biopsies in a neonate who presented with respiratory failure and pulmonary hypertension. Diagnostic lung biopsy at 10 days of age exhibited classic histologic and ultrastructural findings of PIG with diffuse expansion of the alveolar interstitium by glycogenated mesenchymal cells. Subsequent to the patient's clinical improvement, a repeat biopsy at 49 days of age showed significant resolution of the disorder. Colocalization of vimentin-immunopositive cells with both phospho-histone H3 and cleaved caspase-3 demonstrated prominent attenuation of mesenchymal cell proliferation and apoptosis in the second biopsy. Although the self-limited nature of PIG has been described clinically, it has never been documented histologically. We present this case to illustrate the clinical and pathologic resolution of the disorder and speculate that the lesional mesenchymal cells may have transient proliferative capacity.

Is the fetal lung a mineralocorticoid receptor target organ? Induction of cortisol-regulated genes in the ovine fetal lung, kidney and small intestine

BACKGROUND

Lung, kidney and small intestine are involved in fetal volume regulation and amniotic fluid secretion and play a pivotal role in the transition from intrauterine to extrauterine life.

OBJECTIVE

This study was performed to determine the ontogeny of mineralocorticoid receptors (MR) and glucocorticoid receptors (GR), and of MR- and GR-regulated genes and proteins, serum and glucocorticoid-induced kinase (Sgk-1), epithelial sodium channel (ENaC alpha), and Na,K-ATPase alpha1.

METHODS

Lung, renal cortex and medulla, and small intestine were collected from fetuses at 80, 100, 120, 130 and 145 days' gestation and from day 1 and 7 neonatal lambs. Real-time PCR was performed to determine mRNA concentration for MR, GR, the 11 beta-hydroxysteroid dehydrogenases (11 beta-HSD1 and 2), Sgk-1, ENaC alpha, and Na,K-ATPase alpha1. Protein expression of ENaC alpha and Na,K-ATPase alpha1 in whole cell and membrane fractions was determined by immunoblotting.

RESULTS

Expression of corticosteroid-induced genes in renal cortex increases at term; in small intestine the induction occurs postnatally. In contrast, in lung expression of MR and GR mRNAs were greater at 100 days to term than postnatally and 11 beta-HSD1 peaked at 145 days; the corticosteroid-induced genes also increased prenatally: Sgk-1 and ENaC alpha increased by 120 days, peaking at 145 days, and Na,K-ATPase alpha1 was greatest at 130 days.

CONCLUSIONS

The expression of high levels of MR and 11 beta-HSD1 in preterm fetal lung suggest low endogenous fetal cortisol may exert actions at the high affinity MR in vivo, leading to increases in expression of sodium channels important in the regulation of lung liquid secretion and reabsorption.

LGL1, a novel branching morphogen in developing kidney, is induced by retinoic acid

Late-gestation lung protein 1 (LGL1) is a glycoprotein secreted by fetal lung mesenchyme that stimulates branching morphogenesis of the developing lung bud. We show that Lgl1 mRNA and protein are also expressed in mesenchymally derived lineages of fetal kidney. Although Lgl1 expression is stimulated by glucocorticoids in kidney cells, cortisol (10−7M) actually suppresses ureteric bud branching of fetal kidneys from HoxB7/GFP mice in explant culture. However, early branching morphogenesis in the lung and kidney is stimulated by retinoic acid, and we identified putative retinoic acid response elements in the Lgl1 promoter. All- trans-retinoic acid (10−6M) stimulated Lgl1 promoter activity and endogenous Lgl1 mRNA expression in vitro. Branching of cultured fetal kidney explants was increased in the presence of all- trans retinoic acid (10−6M). Heterozygous Lgl1 knockout mice were crossed to HoxB7/GFP mice to visualize the extent of ureteric bud branching at fetal stages. At embryonic (E) days E12.5–E13.0, mutant Lgl1+/−embryos showed a 20% reduction in ureteric bud branching compared with wild-type littermates. We propose a model in which retinoic acid stimulates branching morphogenesis by activating Lgl1 early in development. The prominent effects of glucocorticoids on Lgl1 expression in late lung development suggest a second role for LGL1 in alveolar maturation.

The effect of depression, anxiety and early life trauma on the cortisol awakening response during pregnancy: preliminary results

The purpose of this study was to examine the effects of maternal depression and anxiety on the cortisol awakening response (CAR), a marker of the hypothalamic-pituitary-adrenal (HPA) axis function, during pregnancy. Sixty-six pregnant women were studied between 25 and 33 weeks of gestation and were identified as either Depressed (n=33) or healthy, Control (n=33), based on depression scores and lifetime psychiatric history. Saliva samples were collected (passive drool) upon awakening and at +30 and +60 min thereafter. The CAR was not significantly different between women who were depressed during pregnancy compared to healthy control women. However, women taking antidepressant (AD) medication showed an attenuated CAR (time x AD use interaction, p=0.06). Childhood maltreatment (as measured with the Childhood Trauma Questionnaire) was associated with a lower baseline cortisol concentration explaining 12% of the variance, controlling for wake-up time and AD use. There is a complex interplay of factors involved in the HPA axis regulation of vulnerable women during pregnancy, including depression, anxiety, early life stress and psychotropic medication use, which remain unclear. The CAR may provide important information about the maternal HPA axis during pregnancy and warrants further investigation in larger cohorts.

Lung disease and brain development

With the technical progress made in fetal and neonatal intensive care, perinatal mortality has decreased by 25% over the last decade and has expanded the surviving premature population. Prematurity drastically changes the environment of the developing organism. Striking evidence from a number of disciplines has focused attention on the interplay between the developing organism and the circumstances in which it finds itself. The environmental event during a sensitive period in development, induces injury and/or biological adaptations that lead to altered differentiation of tissues. The organism can express specific adaptive responses to its environment which include short-term changes in physiology as well as long-term adjustments. This review addresses these short-term as well as longer-term changes occurring in lung and brain tissue and illustrates how these changes can be studied using advanced imaging techniques such as magnetic resonance imaging