Changes in human placental 5alpha-reductase isoenzyme expression with advancing gestation: effects of fetal sex and glucocorticoid exposure

Labour and premature delivery differentially affect the expression of the endocannabinoid system in the human placenta

Plasma concentrations of N-arachidonyletholamine (AEA), N-oleoylethanolamide (OEA) and N-palmitoylethanolamide (PEA) increase at term and can predict when a woman is likely to go into labour. We hypothesised that increased plasma AEA concentrations in women in preterm and term labour might also be increased and have a function in the placenta at the end of pregnancy. Here we examined the expression of the N-acylethanolamine-modulating enzymes fatty acid amide hydrolase (FAAH) and N-acyl-phosphatidylethanolamine-specific phospholipase-D (NAPE-PLD) and of the cannabinoid receptors (CB1 and CB2) in the placenta and their activation in an in vitro model of the third-trimester placenta to determine if those expressions change with labour and have functional significance. Expression of CB1, CB2, FAAH and NAPE-PLD was examined by immunohistochemistry (IHC) and RT-qPCR in placental samples obtained from four patient groups: preterm not in labour (PTNL), term not in labour (TNL), preterm in labour (PTL) and term in labour (TL). Additionally, the effects of AEA on a third-trimester human cell line (TCL-1) were evaluated. All ECS components were present in the third-trimester placenta, with NAPE-PLD and CB2 being the key modulated proteins in terms of expression. Functionally, AEA reduced TCL-1 cell numbers through the actions of the CB2 receptor whilst CB1 maintained placental integrity through the expression of the transcription regulators histone deacetylase 3, thyroid hormone receptor β 1 and the modulation of 5α reductase type 1. The placenta in the third trimester and at term is different from the placenta in the first trimester with respect to the expression of CB1, CB2, FAAH and NAPE-PLD, and the expression of these proteins is affected by labour. These data suggest that early perturbation of some ECS components in the placenta may cause AEA-induced PTL and thus PTB.

Association between prenatal androgens and cord blood androgens, a path analysis

To determine association paths between prenatal androgens and cord blood androgens. The concentrations of T, FT, DHT, DHEA and SHBG in prenatal venous blood and cord blood were measured in 342 pregnant women and their neonates. The association paths between these hormones in prenatal and cord blood were revealed using Pearson correlation, multiple linear regression and path analysis. CB-T, CB-FT and CB-DHT in male neonates were higher than those in female neonates. In male and female neonates, P-FT was lower than CB-FT; however, P-DHT and P-SHBG were higher than CB-DHT and CB-SHBG, respectively. P-DHEA was lower than CB-DHEA in female newborns. In male neonates, there were association paths of P-T → CB-T → CB-FT → CB-DHT, P-T → CB-FT → CB-DHT, P-T → P-FT → CB-FT → CB-DHT, P-T → P-DHT, CB-DHEA → CB-DHT, CB-DHEA → P-DHT, and CB-DHEA → P-DHEA. In female neonates, there were association paths of P-T → CB-T → CB-FT → CB-DHT, P-T → P-FT → CB-FT → CB-DHT, P-T → P-FT → P-DHT, P-T → P-DHT, P-DHEA → P-DHT, CB-DHEA → P-DHEA, and CB-DHEA → CB-FT. There were differences in the T, FT and DHT concentrations in cord blood between male and female neonates and in the FT, DHT, DHEA, and SHBG concentrations between prenatal and cord blood. P-T and P-FT concentrations were positively associated with CB-T and CB-FT concentrations, while CB-DHEA concentration was positively associated with P-DHEA concentration.

Sexual dimorphism in placental development and its contribution to health and diseases

According to the Developmental Origin of Health and Disease (DOHaD), intrauterine exposure to adverse environments can affect fetus and birth outcomes and lead to long-term disease susceptibility. Evidence has shown that neonatal outcomes and the timing and severity of adult diseases are sexually dimorphic. As the link between mother and fetus, the placenta is an essential regulator of fetal development programming. It is found that the physiological development trajectory of the placenta has sexual dimorphism. Furthermore, under pathological conditions, the placental function undergoes sex-specific adaptation to ensure fetal survival. Therefore, the placenta may be an important mediator of sexual dimorphism in neonatal outcomes and adult disease susceptibility. Few systematic reviews have been conducted on sexual dimorphism in placental development and its underlying mechanisms. In this review, sex chromosomes and sex hormones, as the main reasons for sexual differentiation of the placenta, will be discussed. Besides, in the etiology of fetal-originated adult diseases, overexposure to glucocorticoids is closely related to adverse neonatal outcomes and long-term disease susceptibility. Studies have found that prenatal glucocorticoid overexposure leads to sexually dimorphic expression of placental glucocorticoid receptor isoforms, resulting in different sensitivity of the placenta to glucocorticoids, and may further affect fetal development. The present review examines what is currently known about sex differences in placental development and the underlying regulatory mechanisms of this sex bias. This review highlights the importance of placental contributions to the origins of sexual dimorphism in health and diseases. It may help develop personalized diagnosis and treatment strategies for fetal development in pathological pregnancies.

Development and validation of an LC-MS/MS assay for the quantification of allopregnanolone and its progesterone-derived isomers, precursors, and cortisol/cortisone in pregnancy

Neuroactive steroids are potent neuromodulators that play a critical role in both maternal and fetal health during pregnancy. These stress-responsive compounds are reportedly low in women with perinatal depression and may be associated with poor pregnancy outcomes in animal models. Chronic stress is a risk factor for adverse birth outcomes. Simultaneous quantification of neuroactive steroids, in combination with stress hormones cortisol/cortisone, provides an opportunity to investigate the synergistic relationship of these analytes within the convenience of one assay. A simple, reliable, and sensitive method for quantifying these endogenous compounds is necessary for further research with the potential to advance clinical diagnostic tools during pregnancy. Analytes were extracted from serum with a simple protein precipitation using methanol and then separated and quantified using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). After online extraction, analytes were separated using an Agilent Poroschell 120, 50 × 4.6 mm, 2.7 μm particle size, EC-C18 analytical column. The reliable quantification range was from 0.78 to 1000 ng/mL. QC sample inter- and intraday trueness was between 90 and 110% while inter- and intraday imprecision was less than 10%. Extracted samples were stable up to 7 days at 4 °C and extraction recovery was above 95%. Serum samples from 54 women in pregnancy were analyzed using this method. Here, we provide a validated, fast, and specific assay with sufficient sensitivity that allows for simultaneous quantification of blood serum concentrations of allopregnanolone (3α-hydroxy-5α-pregnan-20-one), pregnanolone (3α-hydroxy-5β-pregnan-20-one), epipregnanolone (3β-hydroxy-5β-pregnan-20-one), pregnenolone, progesterone, cortisol, and cortisone in pregnancy for clinical study samples and clinical diagnostics.

Let's Talk about Placental Sex, Baby: Understanding Mechanisms That Drive Female- and Male-Specific Fetal Growth and Developmental Outcomes

It is well understood that sex differences exist between females and males even before they are born. These sex-dependent differences may contribute to altered growth and developmental outcomes for the fetus. Based on our initial observations in the human placenta, we hypothesised that the male prioritises growth pathways in order to maximise growth through to adulthood, thereby ensuring the greatest chance of reproductive success. However, this male-specific "evolutionary advantage" likely contributes to males being less adaptable to shifts in the in-utero environment, which then places them at a greater risk for intrauterine morbidities or mortality. Comparatively, females are more adaptable to changes in the in-utero environment at the cost of growth, which may reduce their risk of poor perinatal outcomes. The mechanisms that drive these sex-specific adaptations to a change in the in-utero environment remain unclear, but an increasing body of evidence within the field of developmental biology would suggest that alterations to placental function, as well as the feto-placental hormonal milieu, is an important contributing factor. Herein, we have addressed the current knowledge regarding sex-specific intrauterine growth differences and have examined how certain pregnancy complications may alter these female- and male-specific adaptations.

Impaired Oligodendrocyte Development Following Preterm Birth: Promoting GABAergic Action to Improve Outcomes

Preterm birth is associated with poor long-term neurodevelopmental and behavioral outcomes, even in the absence of obvious brain injury at the time of birth. In particular, behavioral disorders characterized by inattention, social difficulties and anxiety are common among children and adolescents who were born moderately to late preterm (32-37 weeks' gestation). Diffuse deficits in white matter microstructure are thought to play a role in these poor outcomes with evidence suggesting that a failure of oligodendrocytes to mature and myelinate axons is responsible. However, there remains a major knowledge gap over the mechanisms by which preterm birth interrupts normal oligodendrocyte development. In utero neurodevelopment occurs in an inhibitory-dominant environment due to the action of placentally derived neurosteroids on the GABA_A receptor, thus promoting GABAergic inhibitory activity and maintaining the fetal behavioral state. Following preterm birth, and the subsequent premature exposure to the ex utero environment, this action of neurosteroids on GABA_A receptors is greatly reduced. Coinciding with a reduction in GABAergic inhibition, the preterm neonatal brain is also exposed to ex utero environmental insults such as periods of hypoxia and excessive glucocorticoid concentrations. Together, these insults may increase levels of the excitatory neurotransmitter glutamate in the developing brain and result in a shift in the balance of inhibitory: excitatory activity toward excitatory. This review will outline the normal development of oligodendrocytes, how it is disrupted under excitation-dominated conditions and highlight how shifting the balance back toward an inhibitory-dominated environment may improve outcomes.

Untargeted Metabolomics Screen of Mid-pregnancy Maternal Serum and Autism in Offspring

Discovering pathophysiologic networks in a blood-based approach may help to generate valuable tools for early treatment or preventive measures in autism. To date targeted or untargeted metabolomics approaches to identify metabolic features and pathways affecting fetal neurodevelopment have rarely been applied to pregnancy samples, that is, an early period potentially relevant for the development of autism spectrum disorders (ASD). We conducted a population-based study relying on autism diagnoses retrieved from California Department of Developmental Services record. After linking cases to and sampling controls from birth certificates, we retrieved stored maternal mid-pregnancy serum samples collected as part of the California Prenatal Screening Program from the California Biobank for children born 2004 to 2010 in the central valley of California. We retrieved serum for 52 mothers whose children developed autism and 62 population controls originally selected from all eligible children matched by birth year and child's sex. Also, we required that these mothers were relatively low or unexposed to air pollution and select pesticides during early pregnancy. We identified differences in metabolite levels in several metabolic pathways, including glycosphingolipid biosynthesis and metabolism, N-glycan and pyrimidine metabolism, bile acid pathways and, importantly, C21-steroid hormone biosynthesis and metabolism. Disturbances in these pathways have been shown to be relevant for neurodevelopment in rare genetic syndromes or implicated in previous studies of autism. This study provides new insight into maternal mid-pregnancy metabolic features possibly related to the development of autism and an incentive to explore whether these pathways and metabolites are useful for early diagnosis, treatment, or prevention. LAY SUMMARY: This study found that in mid-pregnancy the blood of mothers who give birth to a child that develops autism has some characteristic features that are different from those of blood samples taken from control mothers. These features are related to biologic mechanisms that can affect fetal brain development. In the future, these insights may help identify biomarkers for early autism diagnosis and treatment or preventive measures. Autism Res 2020, 13: 1258-1269. © 2020 International Society for Autism Research, Wiley Periodicals, Inc.

Cortisol metabolism in pregnancies with small for gestational age neonates

Small for gestational age (SGA) newborns are often born from hypertensive pregnancies. This study aimed to compare the systemic metabolism of cortisol (F) in pregnancies with SGA and appropriate for gestational age (AGA) infants, considering both the normotensive (NT) and hypertensive patients. We hypothesized that the disturbances in systemic metabolism of F in pre-eclampsia (PE) might be attributed not to hypertension only, but to SGA. The study included 117 pregnants in the third trimester, divided into groups: NT pregnancy and SGA neonate (SGA-NT); NT pregnancy and AGA neonate (AGA-NT; controls), and respective groups with PE: SGA-PE and AGA-PE. We assessed the glucocorticoid balance with the function of enzymes involved in systemic metabolism of F: 11β-hydroxysteroid dehydrogenase type 1 and 2 (11β-HSD1 and 11β-HSD2), 5α- and 5β-reductase. The enzymes' functions were estimated with the levels of F, cortisone (E), and their metabolites in plasma or urine, which we measured with HPLC-FLD and HPLC-MS/MS. The plasma F/E and urinary free F/E (UFF/UFE) ratios correlated significantly only in patients with the normal function of 5α- and 5β-reductase. The increased function of 11β-HSD2 was noted in all pre-eclamptic pregnancies. Increased function of 5α- and 5β-reductase was specific only for SGA-PE pregnancies, and the function of 5α-reductase was dependent on fetal sex. The SGA-NT pregnancies with male fetuses trended towards the higher function of renal 11β-HSD2 and 5β-reductase; SGA-NT pregnancies with female fetuses lacked any systemic glucocorticoid imbalance. In conclusion, systemic metabolism of F is the most intensive in pre-eclamptic pregnancies complicated by SGA with female fetuses. Our study supports the hypothesis about the different origins of PE and idiopathic intrauterine growth restriction and suggests the sex-specific mechanisms responsible for fetal growth restriction.

Knowledge Gaps and Emerging Research Areas in Intrauterine Growth Restriction-Associated Brain Injury

Intrauterine growth restriction (IUGR) is a complex global healthcare issue. Concerted research and clinical efforts have improved our knowledge of the neurodevelopmental sequelae of IUGR which has raised the profile of this complex problem. Nevertheless, there is still a lack of therapies to prevent the substantial rates of fetal demise or the constellation of permanent neurological deficits that arise from IUGR. The purpose of this article is to highlight the clinical and translational gaps in our knowledge that hamper our collective efforts to improve the neurological sequelae of IUGR. Also, we draw attention to cutting-edge tools and techniques that can provide novel insights into this disorder, and technologies that offer the potential for better drug design and delivery. We cover topics including: how we can improve our use of crib-side monitoring options, what we still need to know about inflammation in IUGR, the necessity for more human post-mortem studies, lessons from improved integrated histology-imaging analyses regarding the cell-specific nature of magnetic resonance imaging (MRI) signals, options to improve risk stratification with genomic analysis, and treatments mediated by nanoparticle delivery which are designed to modify specific cell functions.

Does fetal sex affect placental delivery times? A prospective observational study

Objective: The aim of this study was to determine the potential effect of fetal sex on placental delivery times.Study design: This was a prospective observational study of term, singleton, and primiparous pregnant women who underwent vaginal delivery and subsequently delivered a phenotypically normal live infant. Women with labor or pregnancy complications and comorbid diseases were excluded. Women with factors who could lengthen the placental delivery time were also excluded. The cohort was divided into two groups according to fetal sex. A total of 299 vaginal deliveries were included, and placental delivery times were analyzed in both groups.Results: There were 3938 vaginal deliveries during the study period. Of these, 150 male-bearing pregnant women and 149 female-bearing pregnant women who met the inclusion criteria were included in the analysis. The mean placental delivery time was significantly longer in the male-bearing group than the female-bearing group (12.20 versus 8.21 min, p = .01). Birth weight was significantly greater in the male-bearing group than the female-bearing group (3194 versus 3059 g, p = .004). There was no significant between-group difference in maternal age, gestational age, and preconception body mass index (BMI).Conclusion: Fetal sex had a significant effect on the placental delivery time in the present study. Fetal sex should be considered in future clinical trials of placental delivery times.

Timing of prenatal exposure to trauma and altered placental expressions of hypothalamic-pituitary-adrenal axis genes and genes driving neurodevelopment

Prenatal maternal stress increases the risk for negative developmental outcomes in offspring; however, the underlying biological mechanisms remain largely unexplored. In the present study, alterations in placental gene expression associated with maternal stress were examined to clarify the potential underlying epi/genetic mechanisms. Expression levels of 40 selected genes involved in regulating foetal hypothalamic-pituitary-adrenal axis and neurodevelopment were profiled in placental tissues collected from a birth cohort established around the time of Superstorm Sandy. Objective prenatal traumatic stress was defined as whether mothers were exposed to Superstorm Sandy during pregnancy. Among the 275 mother-infant dyads, 181 dyads were delivered before Superstorm Sandy (ie, Control), 66 dyads were exposed to Superstorm Sandy during the first trimester (ie, Early Exposure) and 28 were exposed to Superstorm Sandy during the second or third trimester (ie, Mid-Late Exposure). Across all trimesters, expression of HSD11B2, MAOA, ZNF507 and DYRK1A was down-regulated among those exposed to Superstorm Sandy during pregnancy. Furthermore, trimester-specific differences were also observed: exposure during early gestation was associated with down-regulation of HSD11B1 and MAOB and up-regulation of CRHBP; exposure during mid-late gestation was associated with up-regulation of SRD5A3. The findings of the present study suggest that placental gene expression may be altered in response to traumatic stress exposure during pregnancy, and the susceptibility of these genes is dependent on the time of the exposure during pregnancy. Further studies should aim to clarify the biological mechanisms that underlie trimester-specific exposure by evaluating the differential impact on offspring neurodevelopment later in childhood.

Prenatal dioxin exposure estimated from dioxins in breast milk and sex hormone levels in umbilical cord blood in Vietnamese newborn infants

Dioxin concentrations remain elevated in the environment and humans residing near the former US Air Force base in Bien Hoa city, South Vietnam. We recruited 210 mother-infant pairs for whom breast milk dioxin levels were reported in our previous study. Cord blood samples were collected from 162 mother-infant pairs. We selected 16 cord blood samples with a volume over 20mL and fat content of ≥0.03g. Toxic equivalent levels of polychlorinated dibenzodioxins and polychlorinated dibenzofurans (TEQ-PCDD/Fs) and concentrations of 17 congeners, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), in cord blood were measured and compared with levels in breast milk (Study 1). Levels of 2,3,7,8-TCDD and TEQ-PCDD/Fs in cord blood samples were highly and significantly correlated with those in breast milk samples in the same pairs. This suggests dioxins in breast milk reflect prenatal dioxin exposure. Estradiol (E2) and testosterone (TS) were measured in cord blood serum from 162 samples. Associations between dioxins in breast milk and cord blood sex hormones were analyzed by infant sex, after adjusting for confounding factors (Study 2). Increased levels of TEQ-PCDD/Fs in breast milk were associated with decreased cord blood TS in girls. In boys, a significant reduction of cord blood TS was observed in those exposed to 2,3,7,8-TCDD at high levels (≥5.5pg/g lipid). There was no significant association between E2 and dioxins in breast milk in either sex. These results suggest increased prenatal dioxin exposure is associated with decreased cord TS, but in boys, only high level of 2,3,7,8-TCDD influence cord blood TS.

Early sex-dependent differences in response to environmental stress

Developmental plasticity enables the appearance of long-term effects in offspring caused by exposure to environmental stressors during embryonic and foetal life. These long-term effects can be traced to pre- and post-implantation development, and in both cases, the effects are usually sex specific. During preimplantation development, male and female embryos exhibit an extensive transcriptional dimorphism mainly driven by incomplete X chromosome inactivation. These early developmental stages are crucial for the establishment of epigenetic marks that will be conserved throughout development, making it a particularly susceptible period for the appearance of long-term epigenetic-based phenotypes. Later in development, gonadal formation generates hormonal differences between the sexes, and male and female placentae exhibit different responses to environmental stressors. The maternal environment, including hormones and environmental insults during pregnancy, contributes to sex-specific placental development that controls genetic and epigenetic programming during foetal development, regulating sex-specific differences, including sex-specific epigenetic responses to environmental hazards, leading to long-term effects. This review summarizes several human and animal studies examining sex-specific responses to environmental stressors during both the periconception period (caused by differences in sex chromosome dosage) and placental development (caused by both sex chromosomes and hormones). The identification of relevant sex-dependent trajectories caused by sex chromosomes and/or sex hormones is essential to define diagnostic markers and prevention/intervention protocols.

Allopregnanolone levels and depressive symptoms during pregnancy in relation to single nucleotide polymorphisms in the allopregnanolone synthesis pathway

Allopregnanolone, a neurosteroid whose levels rise throughout gestation, putatively stabilizes antenatal mood. The present study aimed to investigate associations of plasma allopregnanolone to antenatal depressive symptoms, as well as to genetic and obstetric factors. Allopregnanolone plasma levels from 284 pregnant women were measured around gestational week 18. Haplotype tag single nucleotide polymorphisms in the aldo-keto reductase family 1, members C2 and C4 (AKR1C2, AKR1C4), and steroid 5 alpha-reductase 1 and 2 (SRD5A1, and SRD5A2) genes were genotyped in a larger sample of pregnant women (n=1351). The Edinburgh Postnatal Depression Scale (EPDS) was administered via web-questionnaires in gestational weeks 17 and 32. Demographic and obstetric data was retrieved from web-questionnaires and medical records. There was no association between allopregnanolone levels and depressive symptoms. Furthermore, no associations between allopregnanolone level and synthesis pathway genotypes were found after accounting for multiple comparisons. However, exploratory analyses suggested that the women who were homozygous for the minor allele of the AKR1C2 polymorphism rs1937863 had nominally lower allopregnanolone levels and lower depression scores in gestational week 17, but also the highest increase in depression scores between week 17 and 32. Additionally, higher body mass index was associated with lower allopregnanolone levels. The results do not support second trimester plasma allopregnanolone as a mood stabilizing factor. However, we speculate that AKR1C2 variation may alter the susceptibility to depressive symptoms through effects on central allopregnanolone synthesis. Another implication of this study is that the relationship between neuroactive steroids and obesity in pregnancy deserves to be investigated.

Review: Placental adaptations to the presence of maternal asthma during pregnancy

Asthma is a highly prevalent chronic medical condition affecting an estimated 12% of pregnant, women each year, with prevalence of asthma greatest (up to 16%) among the socially disadvantaged. Maternal asthma is associated with significant perinatal morbidity and mortality including preterm births, neonatal hospitalisations and low birthweight outcomes each year. We have identified that the placenta adapts to the presence of chronic, maternal asthma during pregnancy in a sex specific manner that may confer sex differences in fetal outcome. The male fetus was at greater risk of a poor outcome than a female fetus in the presence of maternal asthma and an acute inflammatory event such as an asthma exacerbation. This review will examine the role of sex specific differences in placental function on fetal growth and survival.

The Fascinating and Complex Role of the Placenta in Pregnancy and Fetal Well-being

Existing evidence implicates the placenta as the origin of some common pregnancy complications. Moreover, some maternal conditions, such as inadequate nutrition, diabetes, and obesity, are known to adversely affect placental function, with subsequent negative impact on the fetus and newborn. The placenta may also contribute to fetal programming with health consequences into adulthood, such as cardiovascular, metabolic, and mental health disorders. There is evidence that altered placental development, specifically impaired trophoblast invasion and spiral artery remodeling in the first trimester, is the origin of preeclampsia. Prenatal care providers who understand the relationships between placental health and maternal-newborn health can better inform and guide women to optimize health early in pregnancy and prior to conception. This article reviews the current understanding of placental function; placental contributions to normal fetal brain development and timing of birth; and impact of maternal nutrition, obesity, and diabetes on the placenta.

Loss of neurosteroid-mediated protection following stress during fetal life

Elevated levels of neurosteroids during late gestation protect the fetal brain from hypoxia/ischaemia and promote neurodevelopment. Suppression of allopregnanolone production during pregnancy leads to the onset of seizure-like activity and potentiates hypoxia-induced brain injury. Markers of myelination are reduced and astrocyte activation is increased. The placenta has a key role in maintaining allopregnanolone concentrations in the fetal circulation and brain during gestation and levels decline markedly after both normal and preterm birth. This leads to the preterm neonate developing in a neurosteroid deficient environment between delivery and term equivalence. The expression of 5α-reductases is also lower in the fetus prior to term. These deficiencies in neurosteroid exposure may contribute to the increase in incidence of the adverse patterns of behaviour seen in children that are born preterm. Repeated exposure to glucocorticoid stimulation suppresses 5α-reductase expression and allopregnanolone levels in the fetus and results in reduced myelination. Both fetal growth restriction and prenatal maternal stress lead to increased cortisol concentrations in the maternal and fetal circulation. Prenatal stress results in reduced expression of key GABAA receptor subunits that normally heighten neurosteroid sensitivity. These stressors also result in altered placental allopregnanolone metabolism pathways. These findings suggest that reduced neurosteroid production and action in the perinatal period may contribute to some of the adverse neurodevelopmental and behavioural outcomes that result from these pregnancy compromises. Studies examining perinatal steroid supplementation therapy with non-metabolisable neurosteroid analogues to improve these outcomes are warranted.

Sex-Specific Placental Responses in Fetal Development

The placenta is an ephemeral but critical organ for the survival of all eutherian mammals and marsupials. It is the primary messenger system between the mother and fetus, where communicational signals, nutrients, waste, gases, and extrinsic factors are exchanged. Although the placenta may buffer the fetus from various environmental insults, placental dysfunction might also contribute to detrimental developmental origins of adult health and disease effects. The placenta of one sex over the other might possess greater ability to respond and buffer against environmental insults. Given the potential role of the placenta in effecting the lifetime health of the offspring, it is not surprising that there has been a resurging interest in this organ, including the Human Placental Project launched by the National Institutes of Child Health and Human Development. In this review, we will compare embryological development of the laboratory mouse and human chorioallantoic placentae. Next, evidence that various species, including humans, exhibit normal sex-dependent structural and functional placental differences will be examined followed by how in utero environmental changes (nutritional state, stress, and exposure to environmental chemicals) might interact with fetal sex to affect this organ. Recent data also suggest that paternal state impacts placental function in a sex-dependent manner. The research to date linking placental maladaptive responses and later developmental origins of adult health and disease effects will be explored. Finally, we will focus on how sex chromosomes and epimutations may contribute to sex-dependent differences in placental function, the unanswered questions, and future directions that warrant further consideration.

Increased placental neurosteroidogenic gene expression precedes poor outcome in the preterm guinea pig

Placental 5α-reductase (5αR) is influenced by in utero compromises and has a role in regulating neuroactive steroid concentrations in the fetus. The objective of this study was to determine if changes in placental 5αR were associated with neonatal outcome after birth. Guinea pigs were delivered by cesarean section at term (GA69, n=22) or preterm (GA62, n=36) and the placenta collected. Preterm neonates were maintained for 24 h unless their condition deteriorated before this time. Enzyme mRNA expression of 5αR type-1 and 5αR type-2 were determined using real-time PCR. All preterm neonates had significantly higher 5αR2 expression in their placenta compared with placentae from term neonates (P<0.0001). Expression was also markedly higher in the placentae from neonates that did not survive until 24 h, compared with surviving preterm neonates (P=0.04). These findings suggest differences of in utero neurosteroidogenic capacity between surviving and non-surviving preterm guinea pig neonates. The increased 5αR2 mRNA expression in the placenta of non-survivors suggests an induction of the neurosteroid pathway due to prior exposure to an in utero compromise, with such exposure possibly a predisposing factor that contributed to their poor ex utero outcome.

Allopregnanolone in the brain: protecting pregnancy and birth outcomes

A successful pregnancy requires multiple adaptations in the mother's brain that serve to optimise foetal growth and development, protect the foetus from adverse prenatal programming and prevent premature delivery of the young. Pregnancy hormones induce, organise and maintain many of these adaptations. Steroid hormones play a critical role and of particular importance is the progesterone metabolite and neurosteroid, allopregnanolone. Allopregnanolone is produced in increasing amounts during pregnancy both in the periphery and in the maternal and foetal brain. This review critically examines a role for allopregnanolone in both the maternal and foetal brain during pregnancy and development in protecting pregnancy and birth outcomes, with particular emphasis on its role in relation to stress exposure at this time. Late pregnancy is associated with suppressed stress responses. Thus, we begin by considering what is known about the central mechanisms in the maternal brain, induced by allopregnanolone, that protect the foetus(es) from exposure to harmful levels of maternal glucocorticoids as a result of stress during pregnancy. Next we discuss the central mechanisms that prevent premature secretion of oxytocin and consider a role for allopregnanolone in minimising the risk of preterm birth. Allopregnanolone also plays a key role in the foetal brain, where it promotes development and is neuroprotective. Hence we review the evidence about disruption to neurosteroid production in pregnancy, through prenatal stress or other insults, and the immediate and long-term adverse consequences for the offspring. Finally we address whether progesterone or allopregnanolone treatment can rescue some of these deficits in the offspring.

Neuroactive steroids in pregnancy: key regulatory and protective roles in the foetal brain

Neuroactive steroid concentrations are remarkably high in the foetal brain during late gestation. These concentrations are maintained by placental progesterone synthesis and the interaction of enzymes in the placenta and foetal brain. 5α-Pregnane-3α-ol-20-one (allopregnanolone) is a key neuroactive steroid during foetal life, although other 3α-hydroxy-pregnanes may make an additional contribution to neuroactive steroid action. Allopregnanolone modulates GABAergic inhibition to maintain a suppressive action on the foetal brain during late gestation. This action suppresses foetal behaviour and maintains the appropriate balance of foetal sleep-like behaviours, which in turn are important to normal neurodevelopment. Neuroactive steroid-induced suppression of excitability has a key role in protecting the foetal brain from acute hypoxia/ischaemia insults. Hypoxia-induced brain injury is markedly increased if neuroactive steroid levels are suppressed and there is increased seizure activity. There is also a rapid increase in allopregnanolone synthesis and hence levels in response to acute stress that acts as an endogenous protective mechanism. Allopregnanolone has a trophic role in regulating development, maintaining normal levels of apoptosis and increasing myelination during late gestation in the brain. In contrast, chronic foetal stressors, including intrauterine growth restriction, do not increase neuroactive steroid levels in the brain and exposure to repeated synthetic corticosteroids reduce neuroactive steroid levels. The reduced availability of neuroactive steroids may contribute to the adverse effects of chronic stressors on the foetal and newborn brain. Preterm birth also deprives the foetus of neuroactive steroid mediated protection and may increase vulnerability to brain injury and suboptimal development. These finding suggest replacement therapies should be explored. This article is part of a Special Issue entitled 'Pregnancy and steroids'.

5α-Reduced glucocorticoids: a story of natural selection

5α-Reduced glucocorticoids (GCs) are formed when one of the two isozymes of 5α-reductase reduces the Δ(4-5) double bond in the A-ring of GCs. These steroids are largely viewed inert, despite the acceptance that other 5α-dihydro steroids, e.g. 5α-dihydrotestosterone, retain or have increased activity at their cognate receptors. However, recent findings suggest that 5α-reduced metabolites of corticosterone have dissociated actions on GC receptors (GRs) in vivo and in vitro and are thus potential candidates for safer anti-inflammatory steroids. 5α-Dihydro- and 5α-tetrahydro-corticosterone can bind with GRs, but interest in these compounds had been limited, since they only weakly activated metabolic gene transcription. However, a greater understanding of the signalling mechanisms has revealed that transactivation represents only one mode of signalling via the GR and recently the abilities of 5α-reduced GCs to suppress inflammation have been demonstrated in vitro and in vivo. Thus, the balance of parent GC and its 5α-reduced metabolite may critically affect the profile of GR signalling. 5α-Reduction of GCs is up-regulated in liver in metabolic disease and may represent a pathway that protects from both GC-induced fuel dyshomeostasis and concomitant inflammatory insult. Therefore, 5α-reduced steroids provide hope for drug development, but may also act as biomarkers of the inflammatory status of the liver in metabolic disease. With these proposals in mind, careful attention must be paid to the possible adverse metabolic effects of 5α-reductase inhibitors, drugs that are commonly administered long term for the treatment of benign prostatic hyperplasia.

Mortality and adverse neurologic outcomes are greater in preterm male infants

OBJECTIVES

To determine whether male gender has an effect on survival, early neonatal morbidity, and long-term outcome in neonates born extremely prematurely.

METHODS

Retrospective review of the New South Wales and Australian Capital Territory Neonatal Intensive Care Unit Data Collection of all infants admitted to New South Wales and Australian Capital Territory neonatal intensive care units between January 1998 and December 2004. The primary outcome was hospital mortality and functional impairment at 2 to 3 years follow-up.

RESULTS

Included in the study were 2549 neonates; 54.7% were male. Risks of grade III/IV intraventricular hemorrhage, sepsis, and major surgery were found to be increased in male neonates. Hospital mortality (odds ratio 1.285, 95% confidence interval 1.035-1.595) and moderate to severe functional disability at 2 to 3 years of age (odds ratio 1.877, 95% confidence interval 1.398-2.521) were more likely in male infants. Gender differences for mortality and long-term neurologic outcome loses significance at 27 weeks gestation.

CONCLUSIONS

In the modern era of neonatal management, male infants still have higher mortality and poorer long-term neurologic outcome. Gender differences for mortality and long-term neurologic outcome appear to lose significance at 27 weeks gestation.

Neurosteroids for a successful pregnancy

Steroid hormones play a critical role in the initiation and maintenance of pregnancy. In particular, the important role that the progesterone metabolite, and neurosteroid, allopregnanolone, may play in fetal and adolescent development is becoming increasingly evident. Unlike steroid hormones, neurosteroids act at nontraditional targets in the central and peripheral nervous systems, including GABA(A) receptor complexes. This commentary discusses the three works in this issue that elucidate the important role of allopregnanolone in the mechanisms that regulate stress hypo-sensitivity of rodents in late pregnancy, neuroprotective effects in fetal sheep exposed to a hypoxic insult, and the continuing role that prefrontal cortex formation of allopregnanolone may play on the cognitive development of gestationally stressed rat offspring, grown to adolescence. The narrative that these works comprise was facilitated by the 5(th) International Meeting on Steroids and the Nervous System (Torino, Italy), which is organized to update our knowledge on the relationships between steroid hormones synthesized in different organs and the nervous system. Topics covered in this most recent meeting included sex differences in, and hormonal influences on, cannabinoid-regulated biology; steroids and pain; the importance of co-regulatory factors for steroid receptor action in the brain; mechanism and role of estrogen-induced nonclassical signaling in the brain; vitamin D as the forgotten neurosteroid; neurosteroids and GABA(A) receptors; and pathogenic mechanisms mediated by glucocorticoid receptors in psychiatric disorders. The 6(th) International Meeting on Steroids and the Nervous System will be held in Torino, Italy in February 2011.

Reduced progesterone metabolites in human late pregnancy

In this review, we focused on the intersection between steroid metabolomics, obstetrics and steroid neurophysiology to give a comprehensive insight into the role of sex hormones and neuroactive steroids (NAS) in the mechanism controlling pregnancy sustaining. The data in the literature including our studies show that there is a complex mechanism providing synthesis of either pregnancy sustaining or parturition provoking steroids. This mechanism includes the boosting placental synthesis of CRH with approaching parturition inducing the excessive synthesis of 3beta-hydroxy-5-ene steroid sulfates serving primarily as precursors for placental synthesis of progestogens, estrogens and NAS. The distribution and changing activities of placental oxidoreductases are responsible for the activation or inactivation of the aforementioned steroids, which is compartment-specific (maternal and fetal compartments) and dependent on gestational age, with a tendency to shift the production from the pregnancy-sustaining steroids to the parturition provoking ones with an increasing gestational age. The fetal and maternal livers catabolize part of the bioactive steroids and also convert some precursors to bioactive steroids. Besides the progesterone, a variety of its 5alpha/beta-reduced metabolites may significantly influence the maintenance of human pregnancy, provide protection against excitotoxicity following acute hypoxic stress, and might also affect the pain perception in mother and fetus.

Steroid metabolome in fetal and maternal body fluids in human late pregnancy

Despite the extensive research during the last six decades the fundamental questions concerning the role of steroids in the initiation of human parturition and origin and function of some steroids in pregnancy were not definitely answered. Based on steroid metabolomic data found in the literature and our so far unpublished results, we attempted to bring new insights concerning the role of steroids in the sustaining and termination of human pregnancy, and predictive value of these substances for estimation of term. We also aimed to explain enigmas concerning the biosynthesis of progesterone and its bioactive catabolites considering the conjunctions between placental production of CRH, synthesis of bioactive steroids produced by fetal adrenal, localization of placental oxidoreductases and sustaining of human pregnancy. Evaluation of data available in the literature, including our recent findings as well as our new unpublished data indicates increasing progesterone synthesis and its concurrently increasing catabolism with approaching parturition, confirms declining production of pregnancy sustaining 5β-pregnane steroids providing uterine quiescence in late pregnancy, increased sulfation of further neuroinhibiting and pregnancy sustaining steroids. In contrast to the established concept considering LDL cholesterol as the primary substrate for progesterone synthesis in pregnancy, our data demonstrates the functioning of alternative mechanism for progesterone synthesis, which is based on the utilization of fetal pregnenolone sulfate for progesterone production in placenta. Close relationships were found between localization of placental oxidoreductases and consistently higher levels of sex hormones, neuroactive steroids and their metabolites in the oxidized form in the fetus and in the reduced form in the maternal compartment.

The effect of betamethasone treatment on neuroactive steroid synthesis in a foetal Guinea pig model of growth restriction

There are ongoing concerns that antenatal corticosteroids, which are administered to women at high risk of delivering preterm to reduce the incidence of respiratory distress syndrome, have adverse effects on foetal brain development and subsequent effects on behaviour and learning, when administered as repeated courses. The present study aimed to examine whether repeated betamethasone treatment alters the expression of the key-rate limiting enzyme, 5alpha-reductase, in the synthetic pathway of the potent neuroactive steroid allopregnanolone in the brain and placenta and whether this effect is potentiated in growth restricted foetuses. To investigate this, pregnant guinea pigs carrying either control (sham surgery) or growth-restricted foetuses were treated with vehicle or betamethasone (1 mg/kg/day) for 4 days prior to sacrifice (65d). Placental insufficiency was induced by the ablation of uterine artery branches supplying each placenta at mid gestation, resulting in foetal growth restriction characterised by 'brain sparing'. Real-time reverse transcriptase polymerase chain reaction was used to determine relative 5alpha-reductase type 1 and 2 mRNA expression in the placenta and brain. Immunohistochemistry was used to examine the glial fibrillary acidic protein (GFAP) expression in the subcortical white matter, CA1 and dentate regions of the hippocampus. 5alpha-reductase type 2 mRNA expression in the brain was markedly reduced by betamethasone treatment in male foetuses compared to vehicle-treated controls but not in female foetuses. In addition, 5alpha-reductase type 1 expression in the brain was increased by growth restriction and/or betamethasone treatment in female foetuses but expression in males foetuses did not increase. 5alpha-reductase type 2 expression in the placenta was markedly reduced by betamethasone treatment compared to vehicle-treated control. Intrauterine growth restriction and betamethasone treatment reduced GFAP expression in the CA1 region of the hippocampus in the brains of male but not female foetuses. These data indicate that betamethasone treatment suppresses placental expression and has sexually dimorphic effects on expression of neuroactive steroid synthetic enzymes in the brain. These actions may lead to adverse effects on the developing brain, particularly in male foetuses, such as the observed effects on GFAP expression.

The relationship between cortisol concentrations in pregnancy and systemic vascular resistance in childhood

OBJECTIVE

To assess the relationship between cortisol concentrations in the last trimester of pregnancy and systemic vascular resistance - SVR in childhood.

MATERIALS AND METHODS

This study is part of a cohort involving 130 Brazilian pregnant women and their children, ages 5 to 7years. Maternal cortisol was determined in saliva by an enzyme immunoassay utilizing the mean concentration of 9 samples of saliva (3 in each different day), collected at the same time, early in the morning. SVR was assessed by the HDI/PulseWave CR-2000 Cardiovascular Profiling System(R). Socioeconomic and demographic characteristics and life style factors were determined by a questionnaire. The nutritional status of the women and children was assessed by the body mass index - BMI. The association between maternal cortisol and SVR in childhood was calculated by multivariate linear regression analysis.

RESULTS

There were statistically significant associations between maternal cortisol and SVR (p=0.043) and BMI-z score of the children (p=0.027), controlling for maternal BMI, birth weight, age, and gender of the children.

CONCLUSION

As far as we know this is the first study in the literature assessing the association between cortisol concentrations in pregnancy and SVR in childhood. Overall, the data suggest that exposure to excess glucocorticoid in the prenatal period is associated to vascular complications in childhood, predisposing to cardiovascular diseases in later life.