Developmental Programming, a Pathway to Disease

Excessive Maternal Weight and Diabetes Are Risk Factors for Macrosomia: A Cross-Sectional Study of 42,663 Pregnancies in Uruguay

OBJECTIVE

To evaluate the risk of macrosomia in newborns from women with gestational diabetes, pregestational diabetes, overweight, and obesity in Uruguay in 2012, as well as its association with prolonged pregnancy, maternal age, multiparity, and excessive gestational weight gain (EGWG).

METHODS

We performed a cross-sectional study of 42,663 pregnant women. The risk of macrosomia was studied using logistic regression.

RESULTS

Mean maternal age was 26.7 ± 6.8 years. Pregestational overweight and obesity was present in 20.9% and 10.7% of women, respectively. There were 28.1% and 19.8% of women overweight and obese at the end of the pregnancy, respectively. Furthermore, 0.5% had pregestational diabetes and 8.5% were multiparous. Twenty two percent developed gestational diabetes and 44.9% had EGWG. The prevalence of macrosomia was 7.9%, significantly more prevalent in males (10.0% vs. 5.5%, p<0.005). Univariate analysis showed that obesity and overweight pre-pregnancy, obesity and overweight at the end of pregnancy, EGWG, pregestational diabetes, gestational diabetes, multiparity, prolonged pregnancy, and male newborn were strongly associated with macrosomia (p<0.0001). Maternal age >35 years did not increase the risk of macrosomia. After multiple logistic regression macrosomia was more likely in pre-gestational obese women (OR 1.24; CI 1.07-1.44), overweight women at the end of pregnancy (OR 1.66; CI 1.46-1.87), obese women at the end of pregnancy (OR 2.21; CI 1.90-2.58), women with EGWG (OR 1.78; CI 1.59-1.98), pregestational diabetes (OR 1.75; CI 1.15-2.69), gestational diabetes (OR 1.39; CI 1.25-1.53), prolonged pregnancy (OR 2.67; CI 2.28-3.12), multiparity (OR 1.24; CI 1.04-1.48), and male newborn (OR 1.89; CI 1.72-2.08).

CONCLUSION

Maternal overweight, obesity, EGWG, and gestational diabetes are prevalent in Uruguay, increasing the risk of macrosomia. Efforts to implement strategies to decrease the prevalence of overweight and obesity among women of reproductive age are essential to improve maternal and neonatal outcomes.

Estimating the Strength of Associations Between Prenatal Diet Quality and Child Developmental Outcomes: Results From a Large Prospective Pregnancy Cohort Study

Our aim in this study was to estimate the strength of associations between prenatal diet quality and child behavioral, language, and motor functions in the Norwegian Mother and Child Cohort Study (1999-2008). We created a prenatal diet quality index (PDQI) based on adherence to Norwegian dietary guidelines. Child outcomes were defined as sum scores on the Child Behavior Checklist, the Ages and Stages Questionnaire, and the Child Development Index at ages 18, 36, and 60 months. Using a longitudinal cohort study design and Bayesian hierarchical modeling, we estimated association strengths using inverse probability weighting to account for selection bias. In total, 27,529 mother-child pairs were eligible for inclusion. A 1-standard-deviation increase in PDQI score was associated with an absolute reduction in outcome sum scores of 0.02-0.21 and a 3%-7% relative decrease, with larger decreases seen for language and motor functions than for behavioral functions. PDQI scores were inversely associated with all child functions, but the estimated strength of each association was low. The results indicate that the observed variations in PDQI scores in an industrialized Western society may not profoundly influence the child functions studied.

A Narrative Review of Placental Contribution to Adverse Pregnancy Outcomes in Women With Polycystic Ovary Syndrome

CONTEXT

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy of reproductive-aged women. In pregnancy, women with PCOS experience increased risk of miscarriage, gestational diabetes, preeclampsia, and extremes of fetal birth weight, and their offspring are predisposed to reproductive and cardiometabolic dysfunction in adulthood. Pregnancy complications, adverse fetal outcomes, and developmental programming of long-term health risks are known to have placental origins. These findings highlight the plausibility of placental compromise in pregnancies of women with PCOS.

EVIDENCE SYNTHESIS

A comprehensive PubMed search was performed using terms "polycystic ovary syndrome," "placenta," "developmental programming," "hyperandrogenism," "androgen excess," "insulin resistance," "hyperinsulinemia," "pregnancy," and "pregnancy complications" in both human and animal experimental models.

CONCLUSIONS

There is limited human placental research specific to pregnancy of women with PCOS. Gestational androgen excess and insulin resistance are two clinical hallmarks of PCOS that may contribute to placental dysfunction and underlie the higher rates of maternal-fetal complications observed in pregnancies of women with PCOS. Additional research is needed to prevent adverse maternal and developmental outcomes in women with PCOS and their offspring.

In utero Androgen Excess: A Developmental Commonality Preceding Polycystic Ovary Syndrome?

In utero androgen excess reliably induces polycystic ovary syndrome (PCOS)-like reproductive and metabolic traits in female monkeys, sheep, rats, and mice. In humans, however, substantial technical and ethical constraints on fetal sampling have curtailed safe, pathogenic exploration during gestation. Evidence consistent with in utero origins for PCOS in humans has thus been slow to amass, but the balance now leans toward developmental fetal origins. Given that PCOS is familial and highly heritable, difficulties encountered in discerning genetic contributions to PCOS pathogenesis are puzzling and, to date, accounts for <10% of PCOS presentations. Unaccounted heritability notwithstanding, molecular commonality in pathogenic mechanisms is emerging, suggested by co-occurrence at the same gene loci of (1) PCOS genetic variants (PCOS women), (2) epigenetic alterations in DNA methylation (PCOS women), and (3) bioinformatics, gene networks-identified, epigenetic alterations in DNA methylation (female rhesus monkeys exposed to testosterone (T) in utero). In addition, naturally occurring hyperandrogenism in female monkeys singles out individuals with PCOS-like reproductive and metabolic traits accompanied by somatic biomarkers of in utero T exposure. Such phenotypic and molecular convergence between highly related species suggests not only dual genetic and epigenetic contributions to a developmental origin of PCOS but also common molecular pathogenesis extending beyond humans.

Maternal Obesity, Maternal Overnutrition and Fetal Programming: Effects of Epigenetic Mechanisms on the Development of Metabolic Disorders

BACKGROUND

Maternal obesity and maternal overnutrition, can lead to epigenetic alterations during pregnancy and these alterations can influence fetal and neonatal phenotype which increase the risk of metabolic disorders in later stages of life.

OBJECTIVE

The effects of maternal obesity on fetal programming and potential mechanisms of maternal epigenetic regulation of gene expression which have persistent effects on fetal health and development were investigated.

METHODS

Review of the literature was carried out in order to discuss the effects of maternal obesity and epigenetic mechanisms in fetal programming of metabolic disorders. All abstracts and full-text articles were examined and the most relevant articles were included in this review.

RESULTS

Maternal obesity and maternal overnutrition during fetal period has important overall effects on long-term health. Maternal metabolic alterations during early stages of fetal development can lead to permanent changes in organ structures, cell numbers and metabolism. Epigenetic modifications (DNA methylation, histone modifications, microRNAs) play an important role in disease susceptibility in the later stages of human life. Maternal nutrition alter expression of hypothalamic genes which can increase fetal and neonatal energy intake. Epigenetic modifications may affect the increasing rate of obesity and other metabolic disorders worldwide since the impact of these changes can be passed through generations.

CONCLUSION

Weight management before and during pregnancy, together with healthy nutritional intakes may improve the maternal metabolic environment, which can reduce the risks of fetal programming of metabolic diseases. Further evidence from long-term follow-up studies are needed in order to determine the role of maternal obesity on epigenetic mechanisms.

Examining the predictive accuracy of metabolomics for small-for-gestational-age babies: a systematic review

INTRODUCTION

To date, there is no robust enough test to predict small-for-gestational-age (SGA) infants, who are at increased lifelong risk of morbidity and mortality.

OBJECTIVE

To determine the accuracy of metabolomics in predicting SGA babies and elucidate which metabolites are predictive of this condition.

DATA SOURCES

Two independent researchers explored 11 electronic databases and grey literature in February 2018 and November 2018, covering publications from 1998 to 2018. Both researchers performed data extraction and quality assessment independently. A third researcher resolved discrepancies.

STUDY ELIGIBILITY CRITERIA

Cohort or nested case-control studies were included which investigated pregnant women and performed metabolomics analysis to evaluate SGA infants. The primary outcome was birth weight <10th centile-as a surrogate for fetal growth restriction-by population-based or customised charts.

STUDY APPRAISAL AND SYNTHESIS METHODS

Two independent researchers extracted data on study design, obstetric variables and sampling, metabolomics technique, chemical class of metabolites, and prediction accuracy measures. Authors were contacted to provide additional data when necessary.

RESULTS

A total of 9181 references were retrieved. Of these, 273 were duplicate, 8760 were removed by title or abstract, and 133 were excluded by full-text content. Thus, 15 studies were included. Only two studies used the fifth centile as a cut-off, and most reports sampled second-trimester pregnant women. Liquid chromatography coupled to mass spectrometry was the most common metabolomics approach. Untargeted studies in the second trimester provided the largest number of predictive metabolites, using maternal blood or hair. Fatty acids, phosphosphingolipids and amino acids were the most prevalent predictive chemical subclasses.

CONCLUSIONS AND IMPLICATIONS

Significant heterogeneity of participant characteristics and methods employed among studies precluded a meta-analysis. Compounds related to lipid metabolism should be validated up to the second trimester in different settings.

PROSPERO REGISTRATION NUMBER

CRD42018089985.

Developmental Programming of PCOS Traits: Insights from the Sheep

Polycystic ovary syndrome (PCOS) is a complex disorder that results from a combination of multiple factors, including genetic, epigenetic, and environmental influences. Evidence from clinical and preclinical studies indicates that elevated intrauterine androgen levels increase the susceptibility of the female offspring to develop the PCOS phenotype. Additionally, early postnatal endocrine and metabolic imbalances may act as a "second-hit", which, through activational effects, might unmask or amplify the modifications programmed prenatally, thus culminating in the development of adult disease. Animal models provide unparalleled resources to investigate the effects of prenatal exposure to androgen excess and to elucidate the etiology and progression of disease conditions associated with this occurrence, such as PCOS. In sheep, prenatal treatment with testosterone disrupts the developmental trajectory of the fetus, culminating in adult neuroendocrine, ovarian, and metabolic perturbations that closely resemble those seen in women with PCOS. Our longitudinal studies clearly demonstrate that prenatal exposure to testosterone excess affects both the reproductive and the metabolic systems, leading to a self-perpetuating cycle with defects in one system having an impact on the other. These observations in the sheep suggest that intervention strategies targeting multiple organ systems may be required to prevent the progression of developmentally programmed disorders.

Gestational Diabetes Epigenetically Reprograms the Cart Promoter in Fetal Ovary, Causing Subfertility in Adult Life

Intrauterine exposure to various adverse conditions during fetal development can lead to epigenetic changes in fetal tissues, predisposing those tissues to disease conditions later in life. An example is gestational diabetes (GD), where the offspring has a higher risk of developing obesity, metabolic disorders, or cardiovascular disease in adult life. In this study, using two well-established GD (streptozotocin- and high-fat and high-sugar-induced) mouse models, we report that female offspring from GD dams are predisposed toward fertility problems later in life. This predisposition to fertility problems is due to altered ovarian expression of a peptide called cocaine- and amphetamine-regulated transcript (CART), which is known to negatively affect folliculogenesis and is induced by elevated leptin levels. Results show that the underlying cause of this altered expression is due to fetal epigenetic modifications involving glucose- and insulin-induced miRNA, miR-101, and the phosphatidylinositol 3-kinase/Akt pathway. These signaling events regulate Ezh2, a histone methyltransferase that promotes H3K27me3, a gene-repressive mark, and CBP/p300, a histone acetyltransferase that promotes H3K27ac, a transcription activation mark, in the fetal ovary. Moreover, the CART promoter has depleted 5-methylcytosine (5mC) and enriched 5-hydroxymethylcytosine (5hmC) levels. The depletion of H3K27me3 and 5mC repressive marks and subsequent increase in H3K27ac and 5hmC gene-activating marks convert the Cartpt promoter to a "superpromoter." This makes the Cartpt promoter more sensitive to leptin levels that predispose the GD offspring to fertility problems. Therefore, this study provides a mechanistic insight about fetal epigenome reprogramming that manifests to ovarian dysfunction and subfertility later in adult life.

Mitotically heritable effects of BMAA on striatal neural stem cell proliferation and differentiation

The widespread environmental contaminant β-methylamino-L-alanine (BMAA) is a developmental neurotoxicant that can induce long-term learning and memory deficits. Studies have shown high transplacental transfer of 3H-BMAA and a significant uptake in fetal brain. Therefore, more information on how BMAA may influence growth and differentiation of neural stem cells is required for assessment of the risk to the developing brain. The aim of this study was to investigate direct and mitotically inherited effects of BMAA exposure using primary striatal neurons and embryonic neural stem cells. The neural stem cells were shown to be clearly more susceptible to BMAA exposure than primary neurons. Exposure to 250 µM BMAA reduced neural stem cell proliferation through apoptosis and G2/M arrest. At lower concentrations (50–100 µM), not affecting cell proliferation, BMAA reduced the differentiation of neural stem cells into astrocytes, oligodendrocytes, and neurons through glutamatergic mechanisms. Neurons that were derived from the BMAA-treated neuronal stem cells demonstrated morphological alterations including reduced neurite length, and decreased number of processes and branches per cell. Interestingly, the BMAA-induced changes were mitotically heritable to daughter cells. The results suggest that early-life exposure to BMAA impairs neuronal stem cell programming, which is vital for development of the nervous system and may result in long-term consequences predisposing for both neurodevelopmental disorders and neurodegenerative disease later in life. More attention should be given to the potential adverse effects of BMAA exposure on brain development.

Identification of placental genes linked to selective intrauterine growth restriction (IUGR) in dichorionic twin pregnancies: gene expression profiling study

A linkage of dichorionic (DC) twin pregnancies with selective intrauterine growth restriction (IUGR) to alterations in placental gene expression is unclear. The aim of the study was to identify placental genes related to hypoxia, adipogenesis and human growth which may contribute to IUGR development. The study group (IUGR/AGA) comprised dichorionic (DC) twin pregnancies, where the weight of the twins differed by > 15%; in addition, one twin was small for gestational age (< 10th percentile-SGA) (IUGR) while the other was appropriate for gestational age (> 10th percentile-AGA). In the control group (AGA/AGA), both fetuses were AGA and their weights differed by < 15%. In the first step (selection), placental expression of 260 genes was analysed by commercial PCR profiler array or qPCR primer assay between six pairs of IUGR/AGA twins. In the second stage (verification), the expression of 20 genes with fold change (FC) > 1.5 selected from the first stage was investigated for 75 DC pregnancies: 23 IUGR/AGA vs. 52 AGA/AGA. The expression of Angiopoetin 2, Leptin and Kruppel-like factor 4 was significantly higher, and Glis Family Zinc Finger 3 was lower, in placentas of SGA fetuses (FC = 3.3; 4.4; 1.6; and - 1.8, respectively; p < 0.05). The dysregulation of gene expression related to angiogenesis and growth factors in placentas of twins born from IUGR/AGA pregnancies suggest that these alternations might represent biological fetal adaptation to the uteral condition. Moreover, DC twin pregnancies may be a good model to identify the differences in placental gene expression between SGA and AGA fetuses.

Alterations in sperm-inherited noncoding RNAs associate with late-term fetal growth restriction induced by preconception paternal alcohol use

Using a mouse model, our group recently described an association between chronic paternal alcohol use prior to conception and deficits in offspring growth. Here, we sought to determine the impact of alcohol exposure on male reproductive physiology and the association of sperm-inherited noncoding RNAs with the transmission of the observed growth defects. Alcohol exposure did not appreciably alter male reproductive physiology or fertility. However, chronic alcohol use reproducibly induced late-term fetal growth restriction in the offspring, which correlated with a shift in the proportional ratio of transfer RNA-derived small RNAs to Piwi-interacting RNAs, as well as altered enrichment of microRNAs miR21, miR30, and miR142 in alcohol-exposed sperm. Although our dataset share similarities to prior works examining the impact of paternal stress on offspring phenotype, we were unable to identify any changes in plasma corticosterone, indicating alcohol may alter sperm-inherited noncoding RNAs through distinct mechanisms.

Do prenatal exposures pose a real threat to ovarian function? Bisphenol A as a case study

Fetal development represents a time of potential vulnerability due to rapid cell division, organ development and limited fetal kidney/liver activity for detoxification and metabolism of exposures. Health effects of prenatal toxicant exposure have previously been described, but there is little cohesive evidence surrounding effects on ovarian function. Using bisphenol A (BPA) as a case study, we seek to examine whether a prominent prenatal environmental exposure can pose a real threat to human ovarian function. To do so, we broadly review human oogenesis and menstrual cycle biology. We then present available literature addressing prenatal bisphenol A and diverse outcomes at the level of the ovary. We highlight relevant human cohorts and mammalian models to review the existing data on prenatal exposures and ovarian disruption. Doing so suggests that while current exposures to BPA have not shown marked or consistent results, there is data sufficient to raise concerns regarding ovarian function. Challenges in the examination of this question suggest the need for additional models and pathways by which to expand these examinations in humans.

Early pregnancy exposure to endocrine disrupting chemical mixtures are associated with inflammatory changes in maternal and neonatal circulation

Endocrine disrupting chemicals (EDCs) are ubiquitous, and pregnancy is a sensitive window for toxicant exposure. EDCs may disrupt the maternal immune system, which may lead to poor pregnancy outcomes. Most studies investigate single EDCs, even though "real life" exposures do not occur in isolation. We tested the hypothesis that uniquely weighted mixtures of early pregnancy exposures are associated with distinct changes in the maternal and neonatal inflammasome. First trimester urine samples were tested for 12 phthalates, 12 phenols, and 17 metals in 56 women. Twelve cytokines were measured in first trimester and term maternal plasma, and in cord blood after delivery. Spearman correlations and linear regression were used to relate individual exposures with inflammatory cytokines. Linear regression was used to relate cytokine levels with gestational age and birth weight. Principal component analysis was used to assess the effect of weighted EDC mixtures on maternal and neonatal inflammation. Our results demonstrated that maternal and cord blood cytokines were differentially associated with (1) individual EDCs and (2) EDC mixtures. Several individual cytokines were positively associated with gestational age and birth weight. These observed associations between EDC mixtures and the pregnancy inflammasome may have clinical and public health implications for women of childbearing age.

Antibiotics and the nervous system: More than just the microbes?

The use of antibiotics has recently risen to prominence in neuroscience due to their potential value in studying the microbiota-gut-brain axis. In this context they have been largely employed to illustrate the many influences of the gut microbiota on brain function and behaviour. Much of this research is bolstered by the abnormal behaviour seen in germ-free animals and other well-controlled experiments. However, this literature has largely failed to consider the neuroactive potential of antibiotics themselves, independent from, or in addition to, their microbicidal effects. This is problematic, as clinical as well as experimental literature, largely neglected through the past decade, has clearly demonstrated that broad classes of antibiotics are neuroactive or neurotoxic. This is true even for some antibiotics that are widely regarded as not absorbed in the intestinal tract, and is especially concerning when considering the highly-concentrated and widely-ranging doses that have been used. In this review we will critically survey the clinical and experimental evidence that antibiotics may influence a variety of nervous system functions, from the enteric nervous system through to the brain and resultant behaviour. We will discuss substantial evidence which clearly suggests neuro-activity or -toxicity by most classes of antibiotics. We will conclude that, while evidence for the microbiota-gut-brain axis remains strong, clinical and experimental studies which employ antibiotics to probe it must consider this potential confound.

Hyperandrogenic origins of polycystic ovary syndrome - implications for pathophysiology and therapy

INTRODUCTION

Polycystic ovary syndrome (PCOS) diagnosis comprises combinations of female hyperandrogenism, menstrual irregularity and polycystic ovaries. While it is a familial and highly prevalent endocrine disorder, progress towards a cure is hindered by absence of a definitive pathogenic mechanism and lack of an animal model of naturally occurring PCOS.

AREAS COVERED

These include an overview of PCOS and its potential etiology, and an examination of insights gained into its pathogenic origins. Animal models derived from experimentally-induced hyperandrogenism during gestation, or from naturally-occurring PCOS-like traits, most reliably demonstrate reproductive, neuroendocrine and metabolic pathogenesis.

EXPERT OPINION

Genetic studies, while identifying at least 17 PCOS risk genes, account for <10% of women with PCOS. A number of PCOS risk genes involve regulation of gonadotropin secretion or action, suggesting a reproductive neuroendocrine basis for PCOS pathogenesis. Consistent with this notion, a number of animal models employing fetal androgen excess demonstrate epigenetic induction of PCOS-like traits, including reproductive neuroendocrine and metabolic dysfunction. Monkey models are most comprehensive, while mouse models provide molecular insight, including identifying the androgen receptor, particularly in neurons, as mediating androgen-induced PCOS-like programming. Naturally-occurring female hyperandrogenism is also demonstrated in monkeys. Animal models are poised to delineate molecular gateways to PCOS pathogenesis.

Leukocyte Telomere Length Reflects Prenatal Stress Exposure, But Does Not Predict Atopic Dermatitis Development at 1 Year

Purpose

Prenatal maternal stress affects offspring's atopic dermatitis (AD) development, which is thought to be mediated by the oxidative stress. We aimed to evaluate the difference in leukocyte telomere length (LTL), a marker for exposure to oxidative stress, according to the prenatal stress exposure and the later AD development.

Methods

From a birth cohort (the COhort for Childhood Origin of Asthma and allergic diseases) that had displayed a good epidemiologic association between the exposure to prenatal stress and AD development in the offspring, we selected 68 pairs of samples from 4 subject groups based on the level of prenatal maternal stress and later AD development. The LTL was measured from both cord blood and 1-year peripheral blood, and their LTLs were compared between subject groups. Finally, the proportion of AD development was examined in the subject groups that are reclassified based on subjects' exposure to prenatal stress and there LTL.

Results

Cord-blood LTL was shorter in prenatally stressed infants than in unstressed ones (P = 0.026), which difference was still significant when subjects became 1 year old (P = 0.008). LTL of cord blood, as well as one of the 1-year peripheral blood, was not different according to later AD development at 1 year (P = 0.915 and 0.174, respectively). Shorter LTL made no increase in the proportion of later AD development in either prenatally high-stressed or low-stressed groups (P = 1.000 and 0.473, respectively).

Conclusions

Cord-blood LTL may reflect subjects' exposure to maternal prenatal stress. However, the LTL shortening is not a risk factor of increasing AD development until the age of 1, and a longer investigation may be necessary for validation. Currently, the results doubt the role of LTL shortening as a marker for risk assessment tool for the prenatal stress associated with AD development in the offspring.

Human fetoplacental arterial and venous endothelial cells are differentially programmed by gestational diabetes mellitus, resulting in cell-specific barrier function changes

AIMS/HYPOTHESIS

An adverse intrauterine environment can result in permanent changes in the physiology of the offspring and predispose to diseases in adulthood. One such exposure, gestational diabetes mellitus (GDM), has been linked to development of metabolic disorders and cardiovascular disease in offspring. Epigenetic variation, including DNA methylation, is recognised as a leading mechanism underpinning fetal programming and we hypothesised that this plays a key role in fetoplacental endothelial dysfunction following exposure to GDM. Thus, we conducted a pilot epigenetic study to analyse concordant DNA methylation and gene expression changes in GDM-exposed fetoplacental endothelial cells.

METHODS

Genome-wide methylation analysis of primary fetoplacental arterial endothelial cells (AEC) and venous endothelial cells (VEC) from healthy pregnancies and GDM-complicated pregnancies in parallel with transcriptome analysis identified methylation and expression changes. Most-affected pathways and functions were identified by Ingenuity Pathway Analysis and validated using functional assays.

RESULTS

Transcriptome and methylation analyses identified variation in gene expression linked to GDM-associated DNA methylation in 408 genes in AEC and 159 genes in VEC, implying a direct functional link. Pathway analysis found that genes altered by exposure to GDM clustered to functions associated with 'cell morphology' and 'cellular movement' in healthy AEC and VEC. Further functional analysis demonstrated that GDM-exposed cells had altered actin organisation and barrier function.

CONCLUSIONS/INTERPRETATION

Our data indicate that exposure to GDM programs atypical morphology and barrier function in fetoplacental endothelial cells by DNA methylation and gene expression change. The effects differ between AEC and VEC, indicating a stringent cell-specific sensitivity to adverse exposures associated with developmental programming in utero.

DATA AVAILABILITY

DNA methylation and gene expression datasets generated and analysed during the current study are available at the National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) database ( http://www.ncbi.nlm.nih.gov/geo ) under accession numbers GSE106099 and GSE103552, respectively.

Prenatal stress and the development of psychopathology: Lifestyle behaviors as a fundamental part of the puzzle

Maternal psychological stress, depression, and anxiety during pregnancy (prenatal stress; PNS) are thought to impact fetal development with long-term effects on offspring outcome. These effects would include physical and mental health, including psychopathology. Maternal sleep, diet, and exercise during pregnancy are lifestyle behaviors that are understudied and often solely included in PNS studies as confounders. However, there are indications that these lifestyle behaviors may actually constitute essential mediators between PNS and fetal programming processes. The goal of this theoretical review was to investigate this idea by looking at the evidence for associations between PNS and sleep, diet, and exercise, and by piecing together the information on potential underlying mechanisms and causal pathways through which these factors may affect the offspring. The analysis of the literature led to the conclusion that sleep, diet, and exercise during pregnancy, may have fundamental roles as mediators between PNS and maternal pregnancy physiology. By integrating these lifestyle behaviors into models of prenatal programming of development, a qualitatively higher and more comprehensive understanding of the prenatal origins of psychopathology can be obtained. The review finalizes by discussing some of the present challenges facing the field of PNS and offspring programming, and offering solutions for future research.

DNA methylation of the promoter region of bnip3 and bnip3l genes induced by metabolic programming

BACKGROUND

Environmental changes of biotic or abiotic nature during critical periods of early development may exert a profound influence on physiological functions later in life. This process, named developmental programming can also be driven through parental nutrition. At molecular level, epigenetic modifications are the most likely candidate for persistent modulation of genes expression in later life.

RESULTS

In order to investigate epigenetic modifications induced by programming in rainbow trout, we focused on bnip3 and bnip3l paralogous genes known to be sensitive to environmental changes but also regulated by epigenetic modifications. Two specific stimuli were used: (i) early acute hypoxia applied at embryo stage and (ii) broodstock and fry methionine deficient diet, considering methionine as one of the main methyl-group donor needed for DNA methylation. We observed a programming effect of hypoxia with an increase of bnip3a and the four paralogs of bnip3l expression level in fry. In addition, parental methionine nutrition was correlated to bnip3a and bnip3lb1 expression showing evidence for early fry programming. We highlighted that both stimuli modified DNA methylation levels at some specific loci of bnip3a and bnip3lb1.

CONCLUSION

Overall, these data demonstrate that methionine level and hypoxia stimulus can be of critical importance in metabolic programming. Both stimuli affected DNA methylation of specific loci, among them, an interesting CpG site have been identified, namely - 884 bp site of bnip3a, and may be positively related with mRNA levels.

Prenatal Steroids and Metabolic Dysfunction: Lessons from Sheep

Prenatal exposure to excess steroids or steroid mimics can disrupt the normal developmental trajectory of organ systems, culminating in adult disease. The metabolic system is particularly susceptible to the deleterious effects of prenatal steroid excess. Studies in sheep demonstrate that prenatal exposure to excess native steroids or endocrine-disrupting chemicals with steroidogenic activity, such as bisphenol A, results in postnatal development of numerous cardiometabolic perturbations, including insulin resistance, increased adiposity, altered adipocyte size and distribution, and hypertension. The similarities in the phenotypic outcomes programmed by these different prenatal insults suggest that common mechanisms may be involved, and these may include hormonal imbalances (e.g., hyperandrogenism and hyperinsulinemia), oxidative stress, inflammation, lipotoxicity, and epigenetic alterations. Animal models, including the sheep, provide mechanistic insight into the metabolic repercussions associated with prenatal steroid exposure and represent valuable research tools in understanding human health and disease. Focusing on the sheep model, this review summarizes the cardiometabolic perturbations programmed by prenatal exposure to different native steroids and steroid mimics and discusses the potential mechanisms underlying the development of adverse outcomes.

Lactational programming of glucose homeostasis: a window of opportunity

The window of lactation is a critical period during which nutritional and environmental exposures impact lifelong metabolic disease risk. Significant organ and tissue development, organ expansion and maturation of cellular functions occur during the lactation period, making this a vulnerable time during which transient insults can have lasting effects. This review will cover current literature on factors influencing lactational programming such as milk composition, maternal health status and environmental endocrine disruptors. The underlying mechanisms that have the potential to contribute to lactational programming of glucose homeostasis will also be addressed, as well as potential interventions to reduce offspring metabolic disease risk.

Testing the programming of temperament and psychopathology in two independent samples of children with prenatal substance exposure

Prenatal programming models have rarely been applied to research on children with prenatal substance exposure, despite evidence suggesting that prenatal drug exposure is a form of stress that impacts neurodevelopmental outcomes and risk for psychopathology. Utilizing data from two longitudinal multisite studies comprising children prenatally exposed to substances as well as a nonexposed comparison group (Maternal Lifestyle Study, n = 1,388; Infant Development, Environment, and Lifestyle study, n = 412), we tested whether early phenotypic indicators of hypothesized programming effects, indexed by growth parameters at birth and infant temperament, served as a link between prenatal substance exposure and internalizing and externalizing behavior at age 5. Latent profile analysis indicated that individual differences in reactivity and regulation for infants prenatally exposed to substances was best characterized by four temperament profiles. These profiles were virtually identical across two independent samples, and demonstrated unique associations with adjustment difficulties nearly 5 years later. Results of path analysis using structural equation modeling also showed that increased prenatal substance exposure was linked to poorer growth parameters at birth, profiles of temperamental reactivity in infancy, and internalizing and externalizing behavior at age 5. This pathway was partially replicated across samples. This study was among the first to link known individual-level correlates of prenatal substance exposure into a specific pathway to childhood problem behavior. Implications for the developmental origins of a child's susceptibility to psychopathology as a result of intrauterine substance exposure are discussed.

Transplacental transfer and metabolism of diuron in human placenta

Diuron is a broad-spectrum phenylurea derived herbicide which is commonly used across the globe. Diuron is toxic to the reproductive system of animals and carcinogenic to rat urothelium, and recently found to be genotoxic in human cells. In in vivo, it is metabolized predominately into 3-(3,4-dichlorophenyl)-1-methyl urea (DCPMU) in humans and 3-(3, 4-dichlorophenyl)urea (DCPU) in animals. Information on diuron toxicokinetics and related toxicity in human placenta is absent. We have investigated the toxicokinetics of diuron in ex vivo human placental perfusion and in in vitro human placental microsomes and human trophoblastic cancer cells (BeWo). Diuron crossed human placenta readily in placental perfusion. Furthermore, diuron was metabolized into DCPMU in perfused placenta and in in vitro incubations using microsomes from placentas of smokers. In incubations with placental microsomes from non-smokers, and in BeWo cells, metabolism to DCPMU was detected but only with the highest used diuron concentration (100 μM). Diuron metabolism was inhibited upon addition of α-naphthoflavone, a CYP1A1 inhibitor, underscoring the role of CYP1A1 in the metabolism. In conclusion, it is evident that diuron crosses human placenta and diuron can be metabolized in the placenta to a toxic metabolite via CYP1A1. This implicates in vivo fetal exposure to diuron if pregnant women are exposed to diuron, which may result in fetotoxicity.

Developmental Origins of Disease: Emerging Prenatal Risk Factors and Future Disease Risk

Purpose of review

Many of the diseases and dysfunctions described in the paradigm of the developmental origins of health and disease have been studied in relation to prenatal nutrition or environmental toxicant exposures. Here, we selectively review the current research on four exposures-two nutritional and two environmental-that have recently emerged as prenatal risk factors for long-term health outcomes.

Recent findings

Recent studies have provided strong evidence that prenatal exposure to (1) excessive intake of sugar-sweetened beverages, (2) unhealthy dietary patterns, (3) perfluoroalkyl substances, and (4) fine particulate matter, may increase risk of adverse health outcomes, such as obesity, cardiometabolic dysfunction, and allergy/asthma.

Summary

Emerging prenatal nutritional factors and environmental toxicants influence offspring long-term health. More work is needed to identify the role of paternal exposures and maternal exposures during the preconception period and to further elucidate causality through intervention studies. The ubiquity of these emerging nutritional and environmental exposures makes this area of inquiry of considerable public health importance.

Potential effect of maternal dietary sucrose or fructose syrup on CD36, leptin, and ghrelin-mediated fetal programming of obesity

The influence of HFCS (high fructose corn syrup - free fructose) and sucrose (bound fructose) on fetal appetite signals is unknown. This study aimed to determine the effects of HFCS or sucrose on the peptide-mediated appetite regulation in fetal programming of obesity. Sprague Dawley female rats were administered feed and plain water (control) or water containing maltodextrin (vehicle), sucrose, fructose, or HFCS (20%, w/v) for 12 weeks before mating and throughout pregnancy and lactation (n_dams = 31; n_pups = 207). Maternal chow-feed consumption in the HFCS and sucrose groups and sugar-added drink consumption in the HFCS group were higher compared to the vehicle and control groups (P < 0.05). The total body fat accumulated in sucrose, fructose, and HFCS groups in dams and pups was higher than those in the vehicle and control groups (P < 0.05). The HFCS groups showed lower plasma leptin levels and higher ghrelin levels. Soluble CD36 levels in plasma and tongue samples were high in HFCS groups of dams and pups (P < 0.05). Rather than bound fructose, the free fructose from the maternal diet contributes to the programming of obesity through the disruption of leptin, ghrelin, and CD36 expression involved in appetite regulation.

Pravastatin and-L-arginine combination improves umbilical artery blood flow and neonatal outcomes in dichorionic twin pregnancies through an nitric oxide-dependent vasorelaxant effect

The increase in fetal and neonatal morbidity and mortality associated with twin pregnancies correlates with an increased risk of preterm delivery, low birth weight, and intrauterine growth restriction (IUGR). Although the pathogenesis of IUGR is unclear and thus management remains a major challenge, feto-placental blood vessels are compromised, and altered umbilical blood flow is observed. In this pilot observational study we investigated the effects of pravastatin plus l-arginine on umbilical artery (umb art) blood flow. Between 2013 and 2016, five women received daily doses l-arginine and pravastatin when an umb art pulsatility index above limits for gestational age was observed and concerns about selective growth restrictions arose. All patients showed selective absent or reversed end-diastolic umbilical artery Doppler flow (AREDV) associated with increased perinatal mortality. Pravastatin (PRAV) plus l-arginine (l-Arg) treatment diminished umb art resistance significantly and allowed pregnancy to continue. No signs of acidosis or hypoxia, normal cardiotocography tracing, normal fetal movement and fetal weight gain were observed in the twins that showed abnormal umb art Dopplers. All neonates were born around 33 weeks (median 33 weeks, IQR [31.4-33.0]), thus diminishing substantially the chances for any prematurity-associated adverse neonatal outcomes. The infants now show normal growth and development. In in vitro studies, pravastatin induced relaxation of aortic rings. Murine studies identified were performed to investigate the mechanism behind PRAV+L-Arg beneficial effects. A nitric oxide (NO)-dependent synergistic vasorelaxant effect of PRAV+L-Arg was demonstrated using aortic rings. Increased levels of placental NO and increased synthesis of eNOS in placental endothelial cells were observed in mice treated with PRAV+L-Arg compared to untreated mice and mice treated with PRAV- or L-Arg alone. This study suggests that PRAV plus L-Arg might be a good therapeutic option to improve blood flow in umbilical arteries prolonging pregnancy and improving pregnancy outcomes in twins. A RCT should be organized to confirm these results.

Prenatal androgen exposure causes hypertension and gut microbiota dysbiosis

BACKGROUND

Conditions of excess androgen in women, such as polycystic ovary syndrome (PCOS), often exhibit intergenerational transmission. One way in which the risk for PCOS may be increased in daughters of affected women is through exposure to elevated androgens in utero. Hyperandrogenemic conditions have serious health consequences, including increased risk for hypertension and cardiovascular disease. Recently, gut dysbiosis has been found to induce hypertension in rats, such that blood pressure can be normalized through fecal microbial transplant. Therefore, we hypothesized that the hypertension seen in PCOS has early origins in gut dysbiosis caused by in utero exposure to excess androgen. We investigated this hypothesis with a model of prenatal androgen (PNA) exposure and maternal hyperandrogenemia by single-injection of testosterone cypionate or sesame oil vehicle (VEH) to pregnant dams in late gestation. We then completed a gut microbiota and cardiometabolic profile of the adult female offspring.

RESULTS

The metabolic assessment revealed that adult PNA rats had increased body weight and increased mRNA expression of adipokines: adipocyte binding protein 2, adiponectin, and leptin in inguinal white adipose tissue. Radiotelemetry analysis revealed hypertension with decreased heart rate in PNA animals. The fecal microbiota profile of PNA animals contained higher relative abundance of bacteria associated with steroid hormone synthesis, Nocardiaceae and Clostridiaceae, and lower abundance of Akkermansia, Bacteroides, Lactobacillus, Clostridium. The PNA animals also had an increased relative abundance of bacteria associated with biosynthesis and elongation of unsaturated short chain fatty acids (SCFAs).

CONCLUSIONS

We found that prenatal exposure to excess androgen negatively impacted cardiovascular function by increasing systolic and diastolic blood pressure and decreasing heart rate. Prenatal androgen was also associated with gut microbial dysbiosis and altered abundance of bacteria involved in metabolite production of short chain fatty acids. These results suggest that early-life exposure to hyperandrogenemia in daughters of women with PCOS may lead to long-term alterations in gut microbiota and cardiometabolic function.

Epigenetic control of variation and stochasticity in metabolic disease

BACKGROUND

The alarming rise of obesity and its associated comorbidities represents a medical burden and a major global health and economic issue. Understanding etiological mechanisms underpinning susceptibility and therapeutic response is of primary importance. Obesity, diabetes, and metabolic diseases are complex trait disorders with only partial genetic heritability, indicating important roles for environmental programing and epigenetic effects.

SCOPE OF THE REVIEW

We will highlight some of the reasons for the scarce predictability of metabolic diseases. We will outline how genetic variants generate phenotypic variation in disease susceptibility across populations. We will then focus on recent conclusions about epigenetic mechanisms playing a fundamental role in increasing variability and subsequently disease triggering.

MAJOR CONCLUSIONS

Currently, we are unable to predict or mechanistically define how "missing heritability" drives disease. Unravelling this black box of regulatory processes will allow us to move towards a truly personalized and precision medicine.

Nonhuman primate breath volatile organic compounds associate with developmental programming and cardio-metabolic status

Rodent and nonhuman primate studies indicate that developmental programming by reduced perinatal nutrition negatively impacts life course cardio-metabolic health. We have developed a baboon model in which we feed control mothers (CON) ad libitum while nutrient restricted mothers are fed 70% of ad libitum global feed in pregnancy and lactation. Offspring of nutrient restricted mothers are intrauterine growth restricted (IUGR) at term. By 3.5 years IUGR baboons showed signs of insulin resistance, indicating a pre-diabetic phenotype, in contrast to healthy CON offspring. We hypothesized that a novel breath analysis approach would provide markers of the altered cardio-metabolic state in a non-invasive manner. Here we assess whether exhaled breath volatile organic compounds (VOCs) collected from this unique cohort of juvenile baboons with documented cardio-metabolic dysfunction resulting from in utero programming can be detected from their breath signatures. Breath was collected from male and female CON and IUGR baboons at 4.8 ± 0.2 years (human equivalent ~13 years). Breath VOCs were quantified using a two-dimensional gas chromatography mass spectrometer. Two-way ANOVA, on 76 biologically relevant VOCs identified 27 VOCs (p < 0.05) with altered abundances between groups (sex, birthweight, and sex x birthweight). The 27 VOCs included 2-pentanone, 2-octanone, 2,2,7,7-tetramethyloctane and 3-methyl-1-heptene, which have not previously been associated with cardio-metabolic disease. Unsupervised principal component analysis of these VOCs could discriminate the four clusters defining males, females, CON and IUGR. This study, which is the first to assess quantifiable breath signatures associated with cardio-metabolic programing for any model of IUGR, demonstrates the translational value of this unique model to identify metabolites of programmed cardio-metabolic dysfunction in breath signatures. Future studies are required to validate the translatability of these findings to humans.

Application of a novel social choice paradigm to assess effects of prenatal endocrine-disrupting chemical exposure in rats (Rattus norvegicus)

Endocrine-disrupting chemical (EDC) exposures during critical periods of gestation cause long-lasting behavioral effects, presumably by disturbing hormonal organization of the brain. Among such EDCs are polychlorinated biphenyls (PCBs), a class of industrial chemicals. PCB exposure in utero leads to alterations in mating behaviors and other sexually dimorphic social interactions in rats. Many of the previous studies on social behavior gave the experimental animal a single or binary choice. This study applied a more complex behavioral apparatus, an X-shaped Plexiglas apparatus (FourPlex), that enabled an experimental animal exposed to PCBs or a vehicle to distinguish and choose among 4 stimulus animals of the same or opposite sex, and of different hormonal status. We found that rats were able to differentiate among the stimuli in the FourPlex and showed the expected preference for an opposite sex, hormone-treated rat, particularly for behaviors conducted in proximity. Prenatal treatment caused subtle shifts in behavior toward stimulus rats in the FourPlex; more robust effects were seen for the sexual dimorphisms in behavior. Importantly, the results differ from our previous results of a simple binary choice model, showing that how an animal behaves in a more complex social paradigm does not predict the outcome in a simple choice model, and vice versa. (PsycINFO Database Record

Developmental Programming of Ovarian Functions and Dysfunctions

The pathophysiological mechanisms underlying the origin of several ovarian pathologies remain unclear. In addition to the genetic basis, developmental insults are gaining attention as a basis for the origin of these pathologies. Such early insults include maternal over or under nutrition, stress, and exposure to environmental chemicals. This chapter reviews the development and physiological function of the ovary, the known ovarian pathologies, the developmental check points of ovarian differentiation impacted by developmental insults, the role played by steroidal and metabolic factors as mediaries, the epigenetic mechanisms via which these mediaries induce their effects, and the knowledge gaps for targeting future studies to ultimately aid in the development of improved treatments.

Transgenerational effects of polychlorinated biphenyls: 1. Development and physiology across 3 generations of rats

BACKGROUND

Polychlorinated biphenyls (PCBs) are persistent organic environmental contaminants and known endocrine-disrupting chemicals (EDCs). Previous studies demonstrated that developmental exposure to the weakly estrogenic PCB mixture Aroclor 1221 (A1221) in Sprague-Dawley rats altered sexual development, adult reproductive physiology and body weight. The current study tested the hypothesis that prenatal A1221 exposure not only disrupts these endpoints within an exposed individual's (F₁ generation) lifespan, but may also affect subsequent generations (F₂-F₃).

METHODS

We treated pregnant female rats on embryonic days (E) 16 and E18 with A1221 (1 mg/kg), estradiol benzoate (50 μg/kg, positive estrogenic control), or vehicle (3% DMSO in sesame oil, negative control). Endpoints related to sexually dimorphic developmental trajectories of reproductive and developmental physiology were measured, and as adults, reproductive endocrine status was assessed, in the F₁, F₂, and F₃ generations.

RESULTS

Significant effects of transgenerational EDCs were found for body weight and serum hormones. The A1221 descendants had significantly higher body weight in the F₂-maternal lineage throughout postnatal development, and in F₃-maternal lineage animals after weaning. In females, generation- and lineage-specific effects of exposure were found for serum progesterone and estradiol. Specifically, serum progesterone concentrations were lower in F₂-A1221 females, and higher in F₃-A1221 females, compared to their respective F₂- and F₃-vehicle counterparts. Serum estradiol concentrations were higher in F₃-A1221 than F₃-vehicle females. Reproductive and adrenal organ weights, birth outcomes, sex ratio, and estrous cycles, were unaffected. It is notable that effects of A1221 were only sometimes mirrored by the estrogenic control, EB, indicating that the mechanism of action of A1221 was likely via non-estrogenic pathways.

CONCLUSIONS

PCBs caused body weight and hormonal effects in rats that were not observed in the directly exposed F₁ offspring, but emerged in F₂ and F₃ generations. Furthermore, most effects were in the maternal lineage; this may relate to the timing of exposure of the F₁ fetuses at E16 and 18, when germline (the future F₂ generation) epigenetic changes diverge in the sexes. These results showing transgenerational effects of EDCs have implications for humans, as we are now in the 3rd generation since the Chemical Revolution of the mid-twentieth century, and even banned chemicals such as PCBs have a persistent imprint on the health of our descendants.

Developmental Programming: Impact of Prenatal Testosterone Excess on Steroidal Machinery and Cell Differentiation Markers in Visceral Adipocytes of Female Sheep

Prenatal testosterone (T)-treated female sheep manifest reduced adipocyte size and peripheral insulin resistance. The small adipocyte phenotype may reflect defects in adipogenesis and its steroidal machinery. To test whether prenatal T treatment from gestational days 30 to 90 alters the visceral adipose tissue (VAT) steroidal machinery and reduces adipocyte differentiation, we examined expression of the steroidogenic enzymes, steroid receptors, and adipocyte differentiation markers at fetal day 90 and postnatal ages 10 and 21 months. Because gestational T treatment increases fetal T and maternal insulin, the contributions of these were assessed by androgen receptor antagonist or insulin sensitizer cotreatment, either separately (at fetal day 90 and 21 months of age time points) or together (10 months of age). The effects on adipogenesis were assessed in the VAT-derived mesenchymal stem cells (AT-MSCs) from pre- and postpubertal time points to evaluate the effects of pubertal steroidal changes on adipogenesis. Our results show that VAT manifests potentially a predominant estrogenic intracrine milieu (increased aromatase and estrogen receptor α) and reduced differentiation markers at fetal day 90 and postnatal 21 months of age. These changes appear to involve both androgenic and metabolic pathways. Preliminary findings suggest that prenatal T treatment reduces adipogenesis, decreases expression of differentiation, and increases expression of commitment markers at both pre- and postpubertal time points. Together, these findings suggest that (1) increased commitment of AT-MSCs to adipocyte lineage and decreased differentiation to adipocytes may underlie the small adipocyte phenotype of prenatal T-treated females and (2) excess T-induced changes in steroidal machinery in the VAT likely participate in the programming/maintenance of this defect.

Endocrine Disruptors Leading to Obesity and Related Diseases

The review aims to comprehensively present the impact of exposure to endocrine disruptors (EDs) in relation to the clinical manifestation of obesity and related diseases, including diabetes mellitus, metabolic syndrome, cardiovascular diseases, carcinogenesis and infertility. EDs are strong participants in the obesity epidemic scenery by interfering with cellular morphological and biochemical processes; by inducing inflammatory responses; and by presenting transcriptional and oncogenic activity. Obesity and lipotoxicity enhancement occur through reprogramming and/or remodeling of germline epigenome by exposure to EDs. Specific population groups are vulnerable to ED exposure due to current dietary and environmental conditions. Obesity, morbidity and carcinogenicity induced by ED exposure are an evolving reality. Therefore, a new collective strategic approach is deemed essential, for the reappraisal of current global conditions pertaining to energy management.

Manipulation of the Growth Hormone-Insulin-Like Growth Factor (GH-IGF) Axis: A Treatment Strategy to Reverse the Effects of Early Life Developmental Programming

Evidence from human clinical, epidemiological, and experimental animal models has clearly highlighted a link between the early life environment and an increased risk for a range of cardiometabolic disorders in later life. In particular, altered maternal nutrition, including both undernutrition and overnutrition, spanning exposure windows that cover the period from preconception through to early infancy, clearly highlight an increased risk for a range of disorders in offspring in later life. This process, preferentially termed “developmental programming” as part of the developmental origins of health and disease (DOHaD) framework, leads to phenotypic outcomes in offspring that closely resemble those of individuals with untreated growth hormone (GH) deficiency, including increased adiposity and cardiovascular disorders. As such, the use of GH as a potential intervention strategy to mitigate the effects of developmental malprogramming has received some attention in the DOHaD field. In particular, experimental animal models have shown that early GH treatment in the setting of poor maternal nutrition can partially rescue the programmed phenotype, albeit in a sex-specific manner. Although the mechanisms remain poorly defined, they include changes to endothelial function, an altered inflammasome, changes in adipogenesis and cardiovascular function, neuroendocrine effects, and changes in the epigenetic regulation of gene expression. Similarly, GH treatment to adult offspring, where an adverse metabolic phenotype is already manifest, has shown efficacy in reversing some of the metabolic disorders arising from a poor early life environment. Components of the GH-insulin-like growth factor (IGF)-IGF binding protein (GH-IGF-IGFBP) system, including insulin-like growth factor 1 (IGF-1), have also shown promise in ameliorating programmed metabolic disorders, potentially acting via epigenetic processes including changes in miRNA profiles and altered DNA methylation. However, as with the use of GH in the clinical setting of short stature and GH-deficiency, the benefits of treatment are also, in some cases, associated with potential unwanted side effects that need to be taken into account before effective translation as an intervention modality in the DOHaD context can be undertaken.

Metabolism disrupting chemicals and metabolic disorders

The recent epidemics of metabolic diseases, obesity, type 2 diabetes(T2D), liver lipid disorders and metabolic syndrome have largely been attributed to genetic background and changes in diet, exercise and aging. However, there is now considerable evidence that other environmental factors may contribute to the rapid increase in the incidence of these metabolic diseases. This review will examine changes to the incidence of obesity, T2D and non-alcoholic fatty liver disease (NAFLD), the contribution of genetics to these disorders and describe the role of the endocrine system in these metabolic disorders. It will then specifically focus on the role of endocrine disrupting chemicals (EDCs) in the etiology of obesity, T2D and NAFLD while finally integrating the information on EDCs on multiple metabolic disorders that could lead to metabolic syndrome. We will specifically examine evidence linking EDC exposures during critical periods of development with metabolic diseases that manifest later in life and across generations.

Late gestational intermittent hypoxia induces metabolic and epigenetic changes in male adult offspring mice

KEY POINTS

Late gestation during pregnancy has been associated with a relatively high prevalence of obstructive sleep apnoea (OSA). Intermittent hypoxia, a hallmark of OSA, could impose significant long-term effects on somatic growth, energy homeostasis and metabolic function in offspring. Here we show that late gestation intermittent hypoxia induces metabolic dysfunction as reflected by increased body weight and adiposity index in adult male offspring that is paralleled by epigenomic alterations and inflammation in visceral white adipose tissue. Fetal perturbations by OSA during pregnancy impose long-term detrimental effects manifesting as metabolic dysfunction in adult male offspring.

ABSTRACT

Pregnancy, particularly late gestation (LG), has been associated with a relatively high prevalence of obstructive sleep apnoea (OSA). Intermittent hypoxia (IH), a hallmark of OSA, could impose significant long-term effects on somatic growth, energy homeostasis, and metabolic function in offspring. We hypothesized that IH during late pregnancy (LG-IH) may increase the propensity for metabolic dysregulation and obesity in adult offspring via epigenetic modifications. Time-pregnant female C57BL/6 mice were exposed to LG-IH or room air (LG-RA) during days 13-18 of gestation. At 24 weeks, blood samples were collected from offspring mice for lipid profiles and insulin resistance, indirect calorimetry was performed and visceral white adipose tissues (VWAT) were assessed for inflammatory cells as well as for differentially methylated gene regions (DMRs) using a methylated DNA immunoprecipitation on chip (MeDIP-chip). Body weight, food intake, adiposity index, fasting insulin, triglycerides and cholesterol levels were all significantly higher in LG-IH male but not female offspring. LG-IH also altered metabolic expenditure and locomotor activities in male offspring, and increased number of pro-inflammatory macrophages emerged in VWAT along with 1520 DMRs (P < 0.0001), associated with 693 genes. Pathway analyses showed that genes affected by LG-IH were mainly associated with molecular processes related to metabolic regulation and inflammation. LG-IH induces metabolic dysfunction as reflected by increased body weight and adiposity index in adult male offspring that is paralleled by epigenomic alterations and inflammation in VWAT. Thus, perturbations to fetal environment by OSA during pregnancy can have long-term detrimental effects on the fetus, and lead to persistent metabolic dysfunction in adulthood.

Gestational Hyperandrogenism in Developmental Programming

Androgen excess (hyperandrogenism) is a common endocrine disorder affecting women of reproductive age. The potential causes of androgen excess in women include polycystic ovary syndrome, congenital adrenal hyperplasia (CAH), adrenal tumors, and racial disparity among many others. During pregnancy, luteoma, placental aromatase deficiency, and fetal CAH are additional causes of gestational hyperandrogenism. The present report reviews the various phenotypes of hyperandrogenism during pregnancy and its origin, pathophysiology, and the effect of hyperandrogenism on the fetal developmental trajectory and offspring consequences.

Developmental programming: Interaction between prenatal BPA and postnatal overfeeding on cardiac tissue gene expression in female sheep

Epidemiologic studies and studies in rodents point to potential risks from developmental exposure to BPA on cardiometabolic diseases. Furthermore, it is becoming increasingly evident that the manifestation and severity of adverse outcomes is the result of interaction between developmental insults and the prevailing environment. Consistent with this premise, recent studies in sheep found prenatal BPA treatment prevented the adverse effects of postnatal obesity in inducing hypertension. The gene networks underlying these complex interactions are not known. mRNA-seq of myocardium was performed on four groups of four female sheep to assess the effects of prenatal BPA exposure, postnatal overfeeding and their interaction on gene transcription, pathway perturbations and functional effects. The effects of prenatal exposure to BPA, postnatal overfeeding, and prenatal BPA with postnatal overfeeding all resulted in transcriptional changes (85-141 significant differentially expressed genes). Although the effects of prenatal BPA and postnatal overfeeding did not involve dysregulation of many of the same genes, they affected a remarkably similar set of biological pathways. Furthermore, an additive or synergistic effect was not found in the combined treatment group, but rather prenatal BPA treatment led to a partial reversal of the effects of overfeeding alone. Many genes previously known to be affected by BPA and involved in obesity, hypertension, or heart disease were altered following these treatments, and AP-1, EGR1, and EGFR were key hubs affected by BPA and/or overfeeding. Environ. Mol. Mutagen. 58:4-18, 2017. © 2016 Wiley Periodicals, Inc.

Prenatal Maternal Distress and Allergic Diseases in Offspring: Review of Evidence and Possible Pathways

Recent studies have suggested a close association between prenatal maternal distress and allergic diseases in the offspring. We selected relevant birth-cohort or national registry studies using a keyword search of the PubMed database and summarized current evidence on the impact of prenatal maternal distress on the development of offspring's allergic diseases. Moreover, we postulated possible pathways linking prenatal distress and allergic diseases based on relevant human and animal studies. Both dysregulated hypothalamic-pituitary-adrenal axis and increased oxidative stress may cause structural (altered brain/lung development) and functional (skewed immune development) changes, which may predispose the fetus to developing allergic diseases during childhood. Although many facts are yet to be discovered, changes in the placental response and epigenetic modification are presumed to mediate the whole process from maternal distress to allergic diseases. Maternal prenatal distress can also interact with other physical or environmental factors, including familial or physical factors, indoor and outdoor pollutants, and early childhood psychological distress. The gut-microbiome-brain axis and the role of the microbiome as an immune modulator should be considered when investigating the stress-allergy relationship and exploring potential intervention modalities. Further research is needed, and particular attention should be given to defining the most vulnerable subjects and critical time periods. To this end, studies exploring relevant biomarkers are warranted, which can enable us to explore adequate intervention strategies.

Developmental programming: Interaction between prenatal BPA and postnatal overfeeding on cardiac tissue gene expression in female sheep

Epidemiologic studies and studies in rodents point to potential risks from developmental exposure to BPA on cardiometabolic diseases. Furthermore, it is becoming increasingly evident that the manifestation and severity of adverse outcomes is the result of interaction between developmental insults and the prevailing environment. Consistent with this premise, recent studies in sheep found prenatal BPA treatment prevented the adverse effects of postnatal obesity in inducing hypertension. The gene networks underlying these complex interactions are not known. mRNA-seq of myocardium was performed on four groups of four female sheep to assess the effects of prenatal BPA exposure, postnatal overfeeding and their interaction on gene transcription, pathway perturbations and functional effects. The effects of prenatal exposure to BPA, postnatal overfeeding, and prenatal BPA with postnatal overfeeding all resulted in transcriptional changes (85-141 significant differentially expressed genes). Although the effects of prenatal BPA and postnatal overfeeding did not involve dysregulation of many of the same genes, they affected a remarkably similar set of biological pathways. Furthermore, an additive or synergistic effect was not found in the combined treatment group, but rather prenatal BPA treatment led to a partial reversal of the effects of overfeeding alone. Many genes previously known to be affected by BPA and involved in obesity, hypertension, or heart disease were altered following these treatments, and AP-1, EGR1, and EGFR were key hubs affected by BPA and/or overfeeding. Environ. Mol. Mutagen. 58:4-18, 2017. © 2016 Wiley Periodicals, Inc.

Prenatal Testosterone Programming of Insulin Resistance in the Female Sheep

Insulin resistance, a common feature of metabolic disorders such as obesity, nonalcoholic fatty liver disease, metabolic syndrome, and polycystic ovary syndrome, is a risk factor for development of diabetes. Because sex hormones orchestrate the establishment of sex-specific behavioral, reproductive, and metabolic differences, a role for them in the developmental origin of insulin resistance is also to be expected. Female sheep exposed to male levels of testosterone during fetal life serve as an excellent translational model for delineating programming of insulin resistance. This chapter summarizes the ontogeny of insulin resistance, the tissue-specific changes in insulin sensitivity, and the various factors that are involved in the programming and maintenance of the insulin resistance in adult female sheep that were developmentally exposed to fetal male levels of testosterone during the sexual-differentiation window.

Developmental Programming: Insulin Sensitizer Prevents the GnRH-Stimulated LH Hypersecretion in a Sheep Model of PCOS

Prenatal testosterone (T) treatment recapitulates the reproductive and metabolic phenotypes of polycystic ovary syndrome in female sheep. At the neuroendocrine level, prenatal T treatment results in disrupted steroid feedback on gonadotropin release, increased pituitary sensitivity to GnRH, and subsequent LH hypersecretion. Because prenatal T-treated sheep manifest functional hyperandrogenism and hyperinsulinemia, gonadal steroids and/or insulin may play a role in programming and/or maintaining these neuroendocrine defects. Here, we investigated the effects of prenatal and postnatal treatments with an androgen antagonist (flutamide [F]) or an insulin sensitizer (rosiglitazone [R]) on GnRH-stimulated LH secretion in prenatal T-treated sheep. As expected, prenatal T treatment increased the pituitary responsiveness to GnRH leading to LH hypersecretion. Neither prenatal interventions nor postnatal F treatment normalized the GnRH-stimulated LH secretion. Conversely, postnatal R treatment completely normalized the GnRH-stimulated LH secretion. At the tissue level, gestational T increased pituitary LHβ, androgen receptor, and insulin receptor-β, whereas it reduced estrogen receptor (ER)α protein levels. Although postnatal F normalized pituitary androgen receptor and insulin receptor-β, it failed to prevent an increase in LHβ expression. Contrarily, postnatal R treatment restored ERα and partially normalized LHβ pituitary levels. Immunohistochemical findings confirmed changes in pituitary ERα expression to be specific to gonadotropes. In conclusion, these findings indicate that increased pituitary responsiveness to GnRH in prenatal T-treated sheep is likely a function of reduced peripheral insulin sensitivity. Moreover, results suggest that restoration of ERα levels in the pituitary may be one mechanism by which R prevents GnRH-stimulated LH hypersecretion in this sheep model of polycystic ovary syndrome-like phenotype.

Plane of nutrition affects growth rate, organ size and skeletal muscle satellite cell activity in newborn calves

Plane of nutrition effects on body, tissue and cellular growth in the neonatal calf are poorly understood. The hypothesis that a low plane of nutrition (LPN) would limit skeletal muscle size by reducing fibre growth and muscle progenitor cell activity was tested. At birth, calves were randomly assigned to either a LPN (20% CP, 20% fat; GE=1.9 Mcal/days) or a high plane of nutrition (HPN; 27% CP, 10% fat, GE = 3.8 Mcal/days) in a 2 × 3 factorial design to test the impact of diet on neonatal calf growth, organ weight and skeletal muscle morphometry with time. Groups of calves (n = 4 or 5) were euthanised at 2, 4 and 8 week of age and organ and empty carcass weights were recorded. Body composition was measured by DXA. Longissimus muscle (LM) fibre cross-sectional area (CSA), fibre/mm² and Pax7 were measured by immunohistology. Satellite cells were isolated at each time point and proliferation rates were measured by EdU incorporation. Calves fed a HPN had greater (p < 0.05) BW, ADG and hip height than those fed a LPN for 2, 4 or 8 weeks. HPN calves contained a greater (p < 0.05) percentage of fat tissue than LPN calves. Liver, spleen and thymus weights were less (p < 0.05) in LPN calves than HPN animals. Calves fed HPN had larger (p < 0.05) LM CSA at 8 weeks than LPN fed animals with no differences between the groups in numbers of satellite cells per fibre. Proliferation rates of satellite cells isolated from HPN fed calves were greater (p < 0.05) at 2 weeks than LPN fed animals, which exhibited greater (p < 0.05) proliferation rates at 4 weeks than HPN fed calves. We conclude a LPN diet reduces body growth and organ size and metabolically reprograms satellite cell activity.

Prenatal Exposure to Endocrine Disruptors: A Developmental Etiology for Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is one of the most common and complex endocrinopathies among reproductive-age women. Polycystic ovary syndrome is characterized by symptomatology of oligomenorrhea and androgen excess, with or without presence of polycystic ovarian morphology. The etiology of PCOS is multifactorial, including genetic and environmental components. It has been previously established that prenatal androgen exposure results in a PCOS phenotype in experimental animal models and epidemiologic human studies. Investigators hypothesize that prenatal exposure to endocrine-disrupting chemicals (EDCs) may contribute to PCOS development. This review examines the emerging research investigating prenatal exposure to 3 major classes of EDCs-bisphenol A (BPA), phthalates, and androgenic EDCs-and the development of PCOS and/or PCOS-related abnormalities in humans and animal models. Highlights of this review are as follows: (1) In rodent studies, maternal BPA exposure alters postnatal development and sexual maturation;, (2) gestational exposure to dibutyl phthalate and di(2-ethylhexyl)phthalate results in polycystic ovaries and a hormonal profile similar to PCOS; and (3) androgenic EDCs, nicotine and 3,4,4'-trichlorocarbanilide, create a hyperandrogenic fetal environment and may pose a potential concern. In summary, prenatal exposure to EDCs may contribute to the altered fetal programming hypothesis and explain the significant variability in severity and presentation.