Maternal psychosocial stress during pregnancy alters the epigenetic signature of the glucocorticoid receptor gene promoter in their offspring: a meta-analysis

Fetal and Infant Outcomes in the Offspring of Parents With Perinatal Mental Disorders: Earliest Influences

Mental illness is highly prevalent and runs in families. Mental disorders are considered to enhance the risk for the development of psychopathology in the offspring. This heightened risk is related to the separate and joint effects of inherited genetic vulnerabilities for psychopathology and environmental influences. The early years of life are suggested to be a key developmental phase in the intergenerational psychopathology transmission. Available evidence supports the idea that early exposure to parental psychopathology, during the pregnancy and first postpartum year, may be related to child psychological functioning beyond the postpartum period, up to adulthood years. This not only highlights the importance of intervening early to break the chain of intergenerational transmission of psychopathology but also raises the question of whether early interventions targeting parental mental disorders in this period may alleviate these prolonged adverse effects in the infant offspring. The current article focuses on the specific risk of psychopathology conveyed from mentally ill parents to the offspring during the pregnancy and first postpartum year. We first present a summary of the available evidence on the associations of parental perinatal mental illness with infant psychological outcomes at the behavioral, biological, and neurophysiological levels. Next, we address the effects of early interventions and discuss whether these may mitigate the early intergenerational transmission of risk for psychopathology. The summarized evidence supports the idea that psychopathology-related changes in parents' behavior and physiology in the perinatal period are related to behavioral, biological, and neurophysiological correlates of infant psychological functioning in this period. These alterations may constitute risk for later development of child and/or adult forms of psychopathology and thus for intergenerational transmission. Targeting psychopathology or mother-infant interactions in isolation in the postnatal period may not be sufficient to improve outcomes, whereas interventions targeting both maternal psychopathology and mother-infant interactions seem promising in alleviating the risk of early transmission.

Perinatal depression and infant mental health

A mother's mental health during pregnancy and the first year postpartum is of the utmost importance to the cognitive, social, and emotional development of her child. Perinatal depression is associated with increased risk for wide-ranging adverse child development effects that can affect infant and early childhood mental health. Although effective treatments for perinatal depression exist, it is currently unclear if treatment of maternal depression alone is sufficient to ameliorate the negative effects of maternal depression on child outcomes. Interventions focused on the mother-infant relationship and dyadic interaction may be required to address the potential effect of maternal depression on the child. This paper provides an overview of maternal perinatal depression, the risk it poses for infant/early-childhood mental health, strategies for intervention that include mitigating depression and decreasing risk to the child, and implications for psychiatric nurses who work with perinatal women. Early identification and treatment of perinatal depression are critical to ensure optimal infant development and the child's future mental health.

Reprint of "Epigenetics, maternal prenatal psychosocial stress, and infant mental health"

This paper provides a summary of literature on epigenetic effects and infant health outcomes of maternal psychosocial stress during pregnancy. A search of literature yielded a large body of publications between 2008 and 2018. Relevant articles were selected, and additional sources were located from ancestry searches of reference lists. Results implicate maternal prenatal stress as a source of epigenetic mechanisms that affect fetal brain development and program risk for emotional dysregulation and mental disorders over a lifetime and across generations. Implications for nursing practice are explored at multiple levels of policy advocacy, public education, primary prevention, screening and intervention.

Neonatal amygdalae and hippocampi are influenced by genotype and prenatal environment, and reflected in the neonatal DNA methylome

The amygdala and hippocampus undergo rapid development in early life. The relative contribution of genetic and environmental factors to the establishment of their developmental trajectories has yet to be examined. We performed imaging on neonates and examined how the observed variation in volume and microstructure of the amygdala and hippocampus varied by genotype, and compared with prenatal maternal mental health and socioeconomic status. Gene × Environment models outcompeted models containing genotype or environment only to best explain the majority of measures but some, especially of the amygdaloid microstructure, were best explained by genotype only. Models including DNA methylation measured in the neonate umbilical cords outcompeted the Gene and Gene × Environment models for the majority of amygdaloid measures and minority of hippocampal measures. This study identified brain region-specific gene networks associated with individual differences in fetal brain development. In particular, genetic and epigenetic variation within CUX1 was highlighted.

Prenatal maternal depressive symptoms and infant DNA methylation: a longitudinal epigenome-wide study

Background: Prenatal maternal stress increases the risk of offspring developmental and psychological difficulties. The biological mechanisms behind these associations are mostly unknown. One explanation suggests that exposure of the fetus to maternal stress may influence DNA methylation. However, this hypothesis is largely based on animal studies, and human studies of candidate genes from single timepoints. Aim: The aim of this study was to investigate if prenatal maternal stress, in the form of maternal depressive symptoms, was associated with variation in genome-wide DNA methylation at two timepoints. Methods: One-hundred and eighty-four mother-child dyads were selected from a population of pregnant women in the Little-in-Norway study. The Edinburgh Postnatal Depression Scale (EPDS) measured maternal depressive symptoms. It was completed by the pregnant mothers between weeks 17 and 32 of gestation. DNA was obtained from infant saliva cells at two timepoints (age 6 weeks and 12 months). DNA methylation was measured in 274 samples from 6 weeks (n = 146) and 12 months (n = 128) using the Illumina Infinium HumanMethylation 450 BeadChip. Linear regression analyses of prenatal maternal depressive symptoms and infant methylation were performed at 6 weeks and 12 months separately, and for both timepoints together using a mixed model. Results: The analyses revealed no significant genome-wide association between maternal depressive symptoms and infant DNA methylation in the separate analyses and for both timepoints together. Conclusions: This sample of pregnant women and their infants living in Norway did not reveal associations between maternal depressive symptoms and infant DNA methylation.

Building an Asymmetrical Brain: The Molecular Perspective

The brain is one of the most prominent examples for structural and functional differences between the left and right half of the body. For handedness and language lateralization, the most widely investigated behavioral phenotypes, only a small fraction of phenotypic variance has been explained by molecular genetic studies. Due to environmental factors presumably also playing a role in their ontogenesis and based on first molecular evidence, it has been suggested that functional hemispheric asymmetries are partly under epigenetic control. This review article aims to elucidate the molecular factors underlying hemispheric asymmetries and their association with inner organ asymmetries. While we previously suggested that epigenetic mechanisms might partly account for the missing heritability of handedness, this article extends this idea by suggesting possible alternatives for transgenerational transmission of epigenetic states that do not require germ line epigenetic transmission. This is in line with a multifactorial model of hemispheric asymmetries, integrating genetic, environmental, and epigenetic influencing factors in their ontogenesis.

Nutrigenetics, epigenetics and gestational diabetes: consequences in mother and child

Gestational Diabetes Mellitus (GDM) is the most common metabolic condition during pregnancy and may result in short- and long-term complications for both mother and offspring. The complexity of phenotypic outcomes seems influenced by genetic susceptibility, nutrient-gene interactions and lifestyle interacting with clinical factors. There is strong evidence that not only the adverse genetic background but also the epigenetic modifications in response to nutritional and environmental factors could influence the maternal hyperglycemia in pregnancy and the foetal metabolic programming. In this view, the correlation between epigenetic modifications and their transgenerational effects represents a very interesting field of study. The present review gives insight into the role of gene variants and their interactions with nutrients in GDM. In addition, we provide an overview of the epigenetic changes and their role in the maternal-foetal transmission of chronic diseases. Overall, the knowledge of epigenetic modifications induced by an adverse intrauterine and perinatal environment could shed light on the potential pathophysiological mechanisms of long-term disease development in the offspring and provide useful tools for their prevention.

Persistent Effects of Antenatal Synthetic Glucocorticoids on Endocrine Stress Reactivity From Childhood to Adolescence

CONTEXT

Antenatal synthetic glucocorticoid (sGC) therapy has been identified as a potent programming factor of the hypothalamic-pituitary-adrenal (HPA) axis. We previously observed significantly increased cortisol stress responses in 6- to 11-year-old, term-born children exposed to antenatal sGCs compared with controls. These findings call for longitudinal follow-up studies to evaluate long-term effects of antenatal sGCs, given that adolescence is marked by a substantial shift of HPA axis functioning.

OBJECTIVE

This study aimed to longitudinally investigate the stability of antenatal sGC-related effects on cortisol stress reactivity from childhood to adolescence.

DESIGN, SETTING, AND PARTICIPANTS

To evaluate long-term trajectories of antenatal sGCs, we longitudinally followed a subsample (n = 44) of our children's cohort into adolescence (14 to 18 years old) for a second assessment. To this end, 22 adolescents with antenatal sGC exposure and 22 untreated controls underwent a standardized laboratory stressor [Trier Social Stress Test (TSST)].

RESULTS

Besides a general increase in HPA axis reactivity from childhood to adolescence (P < 0.05), participants treated with antenatal sGCs showed significantly higher cortisol levels in response to the TSST compared with controls during both developmental stages (P < 0.05). Furthermore, we observed a moderating effect of sGCs on rank-order stability of cortisol stress reactivity from childhood to adolescence (P < 0.05) with a trend (P = 0.07) for higher rank-order stability in sGC-exposed individuals (r = 0.37) compared with controls (r = -0.20).

CONCLUSION

These findings suggest that antenatal sGCs yield long-term changes of HPA axis reactivity that persist into adolescence and may confer increased vulnerability for developing stress-related disorders.

Could epigenetics help explain racial disparities in chronic pain?

African Americans disproportionately suffer more severe and debilitating morbidity from chronic pain than do non-Hispanic Whites. These differences may arise from differential exposure to psychosocial and environmental factors such as adverse childhood experiences, racial discrimination, low socioeconomic status, and depression, all of which have been associated with chronic stress and chronic pain. Race, as a social construct, makes it such that African Americans are more likely to experience different early life conditions, which may induce epigenetic changes that sustain racial differences in chronic pain. Epigenetics is one mechanism by which environmental factors such as childhood stress, racial discrimination, economic hardship, and depression can affect gene expression without altering the underlying genetic sequence. This article provides a narrative review of the literature on epigenetics as a mechanism by which differential environmental exposure could explain racial differences in chronic pain. Most studies of epigenetic changes in chronic pain examine DNA methylation. DNA methylation is altered in the glucocorticoid (stress response) receptor gene, NR3C1, which has been associated with depression, childhood stress, low socioeconomic status, and chronic pain. Similarly, DNA methylation patterns of immune cytokine genes have been associated with chronic stress states. Thus, DNA methylation changes may play an essential role in the epigenetic modulation of chronic pain in different races with a higher incidence of epigenetic alterations contributing to more severe and disabling chronic pain in African Americans.

Exploring the effect of antenatal depression treatment on children's epigenetic profiles: findings from a pilot randomized controlled trial

Background

Children prenatally exposed to maternal depression more often show behavioral and emotional problems compared to unexposed children, possibly through epigenetic alterations. Current evidence is largely based on animal and observational human studies. Therefore, evidence from experimental human studies is needed. In this follow-up of a small randomized controlled trial (RCT), DNA-methylation was compared between children of women who had received cognitive behavioral therapy (CBT) for antenatal depression and children of women who had received treatment as usual (TAU). Originally, 54 women were allocated to CBT or TAU. A beneficial treatment effect was found on women’s mood symptoms.

Findings

We describe DNA methylation findings in buccal swab DNA of the 3–7-year-old children (CBT(N) = 12, TAU(N) = 11), at a genome-wide level at 770,668 CpG sites and at 729 CpG sites spanning 16 a priori selected candidate genes, including the glucocorticoid receptor (NR3C1). We additionally explored associations with women’s baseline depression and anxiety symptoms and offspring DNA methylation, regardless of treatment. Children from the CBT group had overall lower DNA methylation compared to children from the TAU group (mean ∆β = − 0.028, 95% CI − 0.035 to − 0.022). Although 68% of the promoter-associated NR3C1 probes were less methylated in the CBT group, with cg26464411 as top most differentially methylated CpG site (p = 0.038), mean DNA methylation of all NR3C1 promoter-associated probes did not differ significantly between the CBT and TAU groups (mean ∆β = 0.002, 95%CI − 0.010 to 0.011). None of the effects survived correction for multiple testing. There were no differences in mean DNA methylation between the children born to women with more severe depression or anxiety compared to children born to women with mild symptoms of depression or anxiety at baseline (mean ∆β (depression) = 0.0008, 95% CI − 0.007 to 0.008; mean ∆β (anxiety) = 0.0002, 95% CI − 0.004 to 0.005).

Conclusion

We found preliminary evidence of a possible effect of CBT during pregnancy on widespread methylation in children’s genomes and a trend toward lower methylation of a CpG site previously shown by others to be linked to depression and child maltreatment. However, none of the effects survived correction for multiple testing and larger studies are warranted.

Trial registration

Trial registration of the original RCT: ACTRN12607000397415. Registered on 2 August 2007.

Fetal programming of neuropsychiatric disorders by maternal pregnancy depression: a systematic mini review

BACKGROUND

Maternal depression complicates a large proportion of pregnancies. Current evidence shows numerous harmful effects on the offspring. Reviews, which include depression, concluded that stress has harmful effects on the offspring's outcomes neuro-cognitive development, temperament traits, and mental disorders.

OBJECTIVE

This mini review of recent studies, sought to narrow the scope of exposure and identify studies specifically assessing prenatal depression and offspring neuropsychiatric outcomes.

STUDY ELIGIBILITY CRITERIA

The review included longitudinal, cohort, cross-sectional, clinical, quasi-experimental, epidemiological, or intervention study designs published in English from 2014 to 2018.

PARTICIPANTS

Study populations included mother-child dyads, mother-father-child triads, mother-alternative caregiver-child triads, and family studies utilizing sibling comparisons.

METHODS

We searched PubMED and Web of Science. Study inclusion and data extraction were based on standardized templates. The quality of evidence was assessed using the Newcastle-Ottawa Scale (NOS).

RESULTS

Thirteen studies examining neuropsychiatric outcomes were included. We judged the evidence to be moderate to high quality.

CONCLUSIONS

Our review supports that maternal prenatal depression is associated with neuropsychiatric adversities in children.

IMPLICATIONS

Future investigations should unravel the biological underpinnings and target timely interventions as early in pregnancy as possible to prevent offspring neuropsychiatric harms.

Stressful Newborn Memories: Pre-Conceptual, In Utero, and Postnatal Events

Early-life stressful experiences are critical for plasticity and development, shaping adult neuroendocrine response and future health. Stress response is mediated by the autonomous nervous system and the hypothalamic-pituitary-adrenal (HPA) axis while various environmental stimuli are encoded via epigenetic marks. The stress response system maintains homeostasis by regulating adaptation to the environmental changes. Pre-conceptual and in utero stressors form the fetal epigenetic profile together with the individual genetic profile, providing the background for individual stress response, vulnerability, or resilience. Postnatal and adult stressful experiences may act as the definitive switch. This review addresses the issue of how preconceptual in utero and postnatal events, together with individual differences, shape future stress responses. Putative markers of early-life adverse effects such as prematurity and low birth weight are emphasized, and the epigenetic, mitochondrial, and genomic architecture regulation of such events are discussed.

Epigenetics, maternal prenatal psychosocial stress, and infant mental health

This paper provides a summary of literature on epigenetic effects and infant health outcomes of maternal psychosocial stress during pregnancy. A search of literature yielded a large body of publications between 2008 and 2018. Relevant articles were selected, and additional sources were located from ancestry searches of reference lists. Results implicate maternal prenatal stress as a source of epigenetic mechanisms that affect fetal brain development and program risk for emotional dysregulation and mental disorders over a lifetime and across generations. Implications for nursing practice are explored at multiple levels of policy advocacy, public education, primary prevention, screening and intervention.

Maternal Lifetime Trauma and Birthweight: Effect Modification by In Utero Cortisol and Child Sex

OBJECTIVES

To evaluate associations between maternal lifetime traumatic stress and offspring birthweight and examine modifying effects of third trimester cortisol and fetal sex.

STUDY DESIGN

Analyses included 314 mother-infant dyads from an ethnically mixed pregnancy cohort. Maternal lifetime trauma was reported via the Life Stressor Checklist-Revised. Fenton birthweight for gestational age z-scores (BWGA-z) were calculated. A 3-cm scalp-nearest maternal hair segment collected at birth was assayed to reflect cumulative third trimester cortisol secretion. Multivariable regression was used to investigate associations between maternal lifetime trauma and BWGA-z and examine 2- and 3-way interactions with cortisol and fetal sex. Because subjects with low or high cortisol levels could represent susceptible populations, varying coefficient models that relax the linearity assumption on cortisol level were used to assess the modification of maternal lifetime trauma associations with BWGA-z as a function of cortisol.

RESULTS

Women were primarily minorities (41% Hispanic, 26% black) with ≤12 years education (63%); 63% reported ≥1 traumatic event. Prenatal cortisol modified the association between maternal lifetime trauma and birthweight. Women with higher lifetime trauma and increased cortisol had significantly lower birthweight infants in males; among males exposed to the 90th percentile of cortisol, a 1-unit increase in trauma score was associated with a 0.19-unit decrease in BWGA-z (95% CI, -0.34 to -0.04). Associations among females were nonsignificant, regardless of cortisol level.

CONCLUSIONS

These findings underscore the need to consider complex interactions among maternal trauma, disrupted in utero cortisol production, and fetal sex to fully elucidate intergenerational effects of maternal lifetime trauma.

Early Life Stress and Epigenetics in Late-onset Alzheimer's Dementia: A Systematic Review

Involvement of life stress in Late-Onset Alzheimer's Disease (LOAD) has been evinced in longitudinal cohort epidemiological studies, and endocrinologic evidence suggests involvements of catecholamine and corticosteroid systems in LOAD. Early Life Stress (ELS) rodent models have successfully demonstrated sequelae of maternal separation resulting in LOAD-analogous pathology, thereby supporting a role of insulin receptor signalling pertaining to GSK-3beta facilitated tau hyper-phosphorylation and amyloidogenic processing. Discussed are relevant ELS studies, and findings from three mitogen-activated protein kinase pathways (JNK/SAPK pathway, ERK pathway, p38/MAPK pathway) relevant for mediating environmental stresses. Further considered were the roles of autophagy impairment, neuroinflammation, and brain insulin resistance. For the meta-analytic evaluation, 224 candidate gene loci were extracted from reviews of animal studies of LOAD pathophysiological mechanisms, of which 60 had no positive results in human LOAD association studies. These loci were combined with 89 gene loci confirmed as LOAD risk genes in previous GWAS and WES. Of the 313 risk gene loci evaluated, there were 35 human reports on epigenomic modifications in terms of methylation or histone acetylation. 64 microRNA gene regulation mechanisms were published for the compiled loci. Genomic association studies support close relations of both noradrenergic and glucocorticoid systems with LOAD. For HPA involvement, a CRHR1 haplotype with MAPT was described, but further association of only HSD11B1 with LOAD found; however, association of FKBP1 and NC3R1 polymorphisms was documented in support of stress influence to LOAD. In the brain insulin system, IGF2R, INSR, INSRR, and plasticity regulator ARC, were associated with LOAD. Pertaining to compromised myelin stability in LOAD, relevant associations were found for BIN1, RELN, SORL1, SORCS1, CNP, MAG, and MOG. Regarding epigenetic modifications, both methylation variability and de-acetylation were reported for LOAD. The majority of up-to-date epigenomic findings include reported modifications in the well-known LOAD core pathology loci MAPT, BACE1, APP (with FOS, EGR1), PSEN1, PSEN2, and highlight a central role of BDNF. Pertaining to ELS, relevant loci are FKBP5, EGR1, GSK3B; critical roles of inflammation are indicated by CRP, TNFA, NFKB1 modifications; for cholesterol biosynthesis, DHCR24; for myelin stability BIN1, SORL1, CNP; pertaining to (epi)genetic mechanisms, hTERT, MBD2, DNMT1, MTHFR2. Findings on gene regulation were accumulated for BACE1, MAPK signalling, TLR4, BDNF, insulin signalling, with most reports for miR-132 and miR-27. Unclear in epigenomic studies remains the role of noradrenergic signalling, previously demonstrated by neuropathological findings of childhood nucleus caeruleus degeneration for LOAD tauopathy.

Hypothalamic-pituitary-adrenal axis and autonomic nervous system reactivity in children prenatally exposed to maternal depression: A systematic review of prospective studies

Depression is a common condition affecting up to 20% of all pregnant women, and is associated with subsequent developmental and behavioral problems in children, such as conduct disorder and ADHD. One proposed mechanism underlying these associations is modification of the fetal hypothalamic pituitary adrenal (HPA)-axis and the autonomic nervous system (ANS), resulting in altered responses to stress. This review examined the evidence regarding altered HPA-axis and ANS reactivity in children prenatally exposed to high maternal depressive symptoms. A systematic search was conducted in the electronic databases MEDLINE, EMBASE and PsycINFO, for studies published till 25 July 2017. A total of 13 studies comprising 2271 mother-infant dyads were included. None of the studies were suitable for meta-analysis. Risk of bias assessment showed low risk for four studies. Only three studies described an independent association between exposure to high maternal prenatal depressive symptoms and altered stress reactivity in children. There is limited evidence of an independent association between prenatal exposure to maternal depression and altered HPA or ANS reactivity in children.

Maternal antenatal mood and child development: an exploratory study of treatment effects on child outcomes up to 5 years

Effective treatment of maternal antenatal depression may ameliorate adverse neurodevelopmental outcomes in offspring. We performed two follow-up rounds of children at age 2 and age 5 whose mothers had received either specialized cognitive-behavioural therapy or routine care for depression while pregnant. Of the original cohort of 54 women, renewed consent was given by 28 women for 2-year follow-up and by 24 women for 5-year follow-up. Child assessments at the 2-year follow-up included the Parenting Stress Index (PSI), Bayley Scales of Infant Development (BSID-III) and the Child Behaviour Checklist (CBCL). The 5-year follow-up included the Wechsler Preschool and Primary Scales of Intelligence (WPPSI-III) and again the CBCL. Treatment during pregnancy showed significant benefits for children's development at age 2, but not at age 5. At 2 years, intervention effects were found with lower scores on the PSI Total score, Parent Domain and Child domain (d=1.44, 1.47, 0.96 respectively). A non-significant trend favoured the intervention group on most subscales of the CBCL and the BSID-III (most notably motor development: d =0.52). In contrast, at 5-year follow-up, no intervention effects were found. Also, irrespective of treatment allocation, higher depression or anxiety during pregnancy was associated with higher CBCL and lower WPPSI-III scores at 5 years. This is one of the first controlled studies to evaluate the long-term effect of antenatal depression treatment on infant neurodevelopmental outcomes, showing some benefit. Nevertheless, caution should be taken interpreting the results because of a small sample size, and larger studies are warranted.

Epigenetic regulation in development: is the mouse a good model for the human?

BACKGROUND

Over the past few years, advances in molecular technologies have allowed unprecedented mapping of epigenetic modifications in gametes and during early embryonic development. This work is allowing a detailed genomic analysis, which for the first time can answer long-standing questions about epigenetic regulation and reprogramming, and highlights differences between mouse and human, the implications of which are only beginning to be explored.

OBJECTIVE AND RATIONALE

In this review, we summarise new low-cell molecular methods enabling the interrogation of epigenetic information in gametes and early embryos, the mechanistic insights these have provided, and contrast the findings in mouse and human.

SEARCH METHODS

Relevant studies were identified by PubMed search.

OUTCOMES

We discuss the levels of epigenetic regulation, from DNA modifications to chromatin organisation, during mouse gametogenesis, fertilisation and pre- and post-implantation development. The recently characterised features of the oocyte epigenome highlight its exceptionally unique regulatory landscape. The chromatin organisation and epigenetic landscape of both gametic genomes are rapidly reprogrammed after fertilisation. This extensive epigenetic remodelling is necessary for zygotic genome activation, but the mechanistic link remains unclear. While the vast majority of epigenetic information from the gametes is erased in pre-implantation development, new insights suggest that repressive histone modifications from the oocyte may mediate a novel mechanism of imprinting. To date, the characterisation of epigenetics in human development has been almost exclusively limited to DNA methylation profiling; these data reinforce that the global dynamics are conserved between mouse and human. However, as we look closer, it is becoming apparent that the mechanisms regulating these dynamics are distinct. These early findings emphasise the importance of investigations of fundamental epigenetic mechanisms in both mouse and humans.

WIDER IMPLICATIONS

Failures in epigenetic regulation have been implicated in human disease and infertility. With increasing maternal age and use of reproductive technologies in countries all over the world, it is becoming ever more important to understand the necessary processes required to establish a developmentally competent embryo. Furthermore, it is essential to evaluate the extent to which these epigenetic patterns are sensitive to such technologies and other adverse environmental exposures.

Maternal and neonatal characteristics of a Canadian urban cohort receiving treatment for opioid use disorder during pregnancy

The epidemic of prescription and non-prescription opioid misuse is of particular importance in pregnancy. The Society of Obstetricians and Gynaecologists of Canada currently recommends opioid replacement therapy with methadone or buprenorphine for opioid-dependent women during pregnancy. This vulnerable segment of the population has been shown to be at increased risk of blood-borne infectious diseases, nutritional insecurity and stress. The objective of this study was to describe an urban cohort of pregnant women on opioid replacement therapy and to evaluate potential effects on the fetus. A retrospective chart review of all women on opioid replacement therapy and their infants who delivered at The Ottawa Hospital General and Civic campuses between January 1, 2013 and March 24, 2017 was conducted. Data were collected on maternal characteristics, pregnancy outcomes, neonatal outcomes and corresponding placental pathology. Maternal comorbidities identified included high rates of infection, tobacco use and illicit substance use, as well as increased rates of placental abruption compared with national averages. Compared with national baseline averages, the mean neonatal birth weight was low, and the incidence of small for gestational age infants and congenital anomalies was high. The incidence of NAS was comparable with estimates from other studies of similar cohorts. Findings support existing literature that calls for a comprehensive interdisciplinary risk reduction approach including dietary, social, domestic, psychological and other supports to care for opioid-dependent women in pregnancy.

Cumulative lifetime maternal stress and epigenome-wide placental DNA methylation in the PRISM cohort

Evolving evidence links maternal stress exposure to changes in placental DNA methylation of specific genes regulating placental function that may have implications for the programming of a host of chronic disorders. Few studies have implemented an epigenome-wide approach. Using the Infinium HumanMethylation450 BeadChip (450K), we investigated epigenome-wide placental DNA methylation in relation to maternal experiences of traumatic and non-traumatic stressors over her lifetime assessed using the Life Stressor Checklist-Revised (LSC-R) survey (n = 207). We found differential DNA methylation at epigenome-wide statistical significance (FDR = 0.05) for 112 CpGs. Additionally, we observed three clusters that exhibited differential methylation in response to high maternal lifetime stress. Enrichment analyses, conducted at an FDR = 0.20, revealed lysine degradation to be the most significant pathway associated with maternal lifetimes stress exposure. Targeted enrichment analyses of the three largest clusters of probes, identified using the gap statistic, were enriched for genes associated with endocytosis (i.e., SMAP1, ANKFY1), tight junctions (i.e., EPB41L4B), and metabolic pathways (i.e., INPP5E, EEF1B2). These pathways, also identified in the top 10 KEGG pathways associated with maternal lifetime stress exposure, play important roles in multiple physiological functions necessary for proper fetal development. Further, two genes were identified to exhibit multiple probes associated with maternal lifetime stress (i.e., ANKFY1, TM6SF1). The methylation status of the probes belonging to each cluster and/or genes exhibiting multiple hits, may play a role in the pathogenesis of adverse health outcomes in children born to mothers with increased lifetime stress exposure.

Developmental Lead Exposure and Prenatal Stress Result in Sex-Specific Reprograming of Adult Stress Physiology and Epigenetic Profiles in Brain

Developmental exposure to lead (Pb) and prenatal stress (PS) both impair cognition, which could derive from their joint targeting of the hypothalamic-pituitary-adrenal axis and the brain mesocorticolimbic (MESO) system, including frontal cortex (FC) and hippocampus (HIPP). Glucocorticoids modulate both FC and HIPP function and associated mediation of cognitive and other behavioral functions. This study sought to determine whether developmental Pb ± PS exposures altered glucocorticoid-related epigenetic profiles in brain MESO regions in offspring of female mice exposed to 0 or 100 ppm Pb acetate drinking water from 2 mos prior to breeding until weaning, with half further exposed to prenatal restraint stress from gestational day 11-18. Overall, changes in females occured in response to Pb exposure. In males, however, Pb-induced neurotoxicity was modulated by PS. Changes in serum corticosterone levels were seen in males, while glucocorticoid receptor changes were seen in both sexes. In contrast, both Pb and PS broadly impacted brain DNA methyltransferases and binding proteins, particularly DNMT1, DNMT3a and methyl-CpG-binding protein 2, with patterns that differed by sex and brain regions. Specifically, in males, effects on FC epigenetic modifiers were primarily influenced by Pb, whereas extensive changes in HIPP were produced by PS. In females, Pb exposure and not PS primarily altered epigenetic modifiers in both FC and HIPP. Collectively, these findings indicate that epigenetic mechanisms may underlie associated neurotoxicity of Pb and of PS, particularly associated cognitive deficits. However, mechanisms by which this may occur will be different in males versus females.

Association of Maternal Psychosocial Stress With Increased Risk of Asthma Development in Offspring

Prenatal maternal psychosocial stress might influence the development of childhood asthma. Evaluating paternal psychosocial stress and conducting a sibling comparison could provide further insight into the role of unmeasured confounding. We examined the associations of parental psychosocial stress during and after pregnancy with asthma at age 7 years in the Norwegian Mother and Child Cohort Study (n = 63,626; children born in 2000-2007). Measures of psychosocial stress included lifetime major depressive symptoms, current anxiety/depression symptoms, use of antidepressants, anxiolytics, and/or hypnotics, life satisfaction, relationship satisfaction, work stress, and social support. Childhood asthma was associated with maternal lifetime major depressive symptoms (adjusted relative risk (aRR) = 1.19, 95% confidence interval (CI): 1.09, 1.30), in addition to symptoms of anxiety/depression during pregnancy (aRR = 1.17, 95% CI: 1.06, 1.29) and 6 months after delivery (aRR = 1.17, 95% CI: 1.07, 1.28). Maternal negative life events during pregnancy (aRR = 1.10, 95% CI: 1.06, 1.13) and 6 months after delivery (aRR = 1.14, 95% CI: 1.11, 1.18) were also associated with asthma. These associations were not replicated when evaluated within sibling groups. There were no associations with paternal psychosocial stress. In conclusion, maternal anxiety/depression and negative life events were associated with offspring asthma, but this might be explained by unmeasured maternal background characteristics that remain stable across deliveries.

Non-invasive biomarkers of fetal brain development reflecting prenatal stress: An integrative multi-scale multi-species perspective on data collection and analysis

Prenatal stress (PS) impacts early postnatal behavioural and cognitive development. This process of 'fetal programming' is mediated by the effects of the prenatal experience on the developing hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS). We derive a multi-scale multi-species approach to devising preclinical and clinical studies to identify early non-invasively available pre- and postnatal biomarkers of PS. The multiple scales include brain epigenome, metabolome, microbiome and the ANS activity gauged via an array of advanced non-invasively obtainable properties of fetal heart rate fluctuations. The proposed framework has the potential to reveal mechanistic links between maternal stress during pregnancy and changes across these physiological scales. Such biomarkers may hence be useful as early and non-invasive predictors of neurodevelopmental trajectories influenced by the PS as well as follow-up indicators of success of therapeutic interventions to correct such altered neurodevelopmental trajectories. PS studies must be conducted on multiple scales derived from concerted observations in multiple animal models and human cohorts performed in an interactive and iterative manner and deploying machine learning for data synthesis, identification and validation of the best non-invasive detection and follow-up biomarkers, a prerequisite for designing effective therapeutic interventions.

Increased methylation at an unexplored glucocorticoid responsive element within exon 1D of NR3C1 gene is related to anxious-depressive disorders and decreased hippocampal connectivity

Among the major psychiatric disorders, anxious-depressive disorders stand out as one of the more prevalent and more frequently associated with hypothalamic-pituitary-adrenal (HPA) axis abnormalities. Methylation at the exon 1_F of the glucocorticoid receptor gene NR3C1 has been associated with both early stress exposure and risk for developing a psychiatric disorder; however, other NR3C1 promoter regions have been underexplored. Exon 1_D emerges as a suggestive new target in stress-related disorders epigenetically sensitive to early adversity. After assessment of 48 monozygotic twin pairs (n=96 subjects) informative for lifetime history of anxious-depressive disorders, they were classified as concordant, discordant or healthy in function of whether both, one or neither twin in each pair had a lifetime diagnosis of anxious-depressive disorders. DNA for epigenetic analysis was extracted from peripheral blood. Exon 1_F and exon 1_D CpG-specific methylation was analysed by means of pyrosequencing technology. Functional magnetic resonance imaging was available for 54 subjects (n=27 twin pairs). Exon 1_D CpG-specific methylation within a glucocorticoid responsive element (GRE) was correlated with familial burden of anxious-depressive disorders (r=0.35, z=2.26, p=0.02). Right hippocampal connectivity was significantly associated with CpG-specific GRE methylation (β=-2.33, t=-2.85, p=0.01). Exon 1_F was uniformly hypomethylated across all subgroups of the present sample. GRE hypermethylation at exon 1_D of the NR3C1 gene in monozygotic twins concordant for anxious-depressive disorders suggests this region plays a role in increasing vulnerability to psychosocial stress, partly mediated by altered hippocampal connectivity.

DNA methylation of the glucocorticoid receptor gene promoter in the placenta is associated with blood pressure regulation in human pregnancy

BACKGROUND

Blood pressure (BP) regulation during pregnancy is influenced by hormones of placental origin. It was shown that the glucocorticoid system is altered in hypertensive pregnancy disorders such as preeclampsia. Epigenetic mechanism might influence the activity of genes involved in placental hormone/hormone receptor synthesis/action during pregnancy.

METHOD

In the current study, we analyzed the association of 5'-C-phosphate-G-3' (CpG) site methylation of different glucocorticoid receptor gene (NR3C1) promoter regions with BP during pregnancy. The study was performed as a nested case-control study (n = 80) out of 1045 mother/child pairs from the Berlin Birth Cohort. Placental DNA was extracted and bisulfite converted. Nested PCR products from six NR3C1 proximal promoter regions [glucocorticoid receptor gene promotor region B (GR-1B), C (GR-1C), D (GR-1D), E (GR-1E), F (GR-1F), and H (GR-1H)] were analyzed by next generation sequencing.

RESULTS

NR3C1 promoter regions GR-1D and GR-1E had a much higher degree of DNA methylation as compared to GR-1B, GR-1F or GR-1H when analyzing the entire study population. Comparison of placental NR3C1 CpG site methylation among hypotensive, normotensive and hypertensive mothers revealed several differently methylated CpG sites in the GR-1F promoter region only. Both hypertension and hypotension were associated with increased DNA methylation of GR-1F CpG sites. These associations were independent of confounding factors, such as family history of hypertension, smoking status before pregnancy and prepregnancy BMI. Assessment of placental glucocorticoid receptor expression by western blot showed that observed DNA methylation differences were not associated with altered levels of placental glucocorticoid receptor expression. However, correlation matrices of all NR3C1 proximal promoter regions demonstrated different correlation patterns of intraregional and interregional DNA methylation in the three BP groups, putatively indicating altered transcriptional control of glucocorticoid receptor isoforms.

CONCLUSION

Our study provides evidence of an independent association between placental NR3C1 proximal promoter methylation and maternal BP. Furthermore, we observed different patterns of NR3C1 promoter methylation in normotensive, hypertensive and hypotensive pregnancy.

Annual Research Review: Early adversity, the hypothalamic-pituitary-adrenocortical axis, and child psychopathology

BACKGROUND

Research on early adversity, stress biology, and child development has grown exponentially in recent years.

FINDINGS

We review the current evidence for the hypothalamic-pituitary-adrenocortical (HPA) axis as a stress-mediating mechanism between various forms of childhood adversity and psychopathology. We begin with a review of the neurobiology of the axis and evidence for relations between early adversity-HPA axis activity and HPA axis activity-psychopathology, as well as discuss the role of regulatory mechanisms and sensitive periods in development.

CONCLUSIONS

We call attention to critical gaps in the literature to highlight next steps in this research including focus on developmental timing, sex differences, stress buffering, and epigenetic regulation. A better understanding of individual differences in the adversity-HPA axis-psychopathology associations will require continued work addressing how multiple biological and behavioral systems work in concert to shape development.

Glucocorticoid receptor gene methylation moderates the association of childhood trauma and cortisol stress reactivity

Exposure to childhood trauma (CT) has been linked to sustained dysregulations of major stress response systems, including findings of both exaggerated and attenuated hypothalamus-pituitary-adrenal (HPA) axis activity. Likewise, CT constitutes a common risk factor for a broad range of psychiatric conditions that involve distinct neuroendocrine profiles. In this study, we investigated the role of epigenetic variability in a stress-related gene as a potential mediator or moderator of such differential trajectories in CT survivors. For this, we screened adult volunteers for CT and recruited a healthy sample of 98 exposed (67 with mild-moderate, 31 with moderate-severe exposure) and 102 control individuals, with an equal number of males and females in each group. DNA methylation (DNA_M) levels of the glucocorticoid receptor exon 1F promoter (NR3C1-1F) at functionally relevant sites were analyzed via bisulfite pyrosequencing from whole blood samples. Participants were exposed to a laboratory stressor (Trier Social Stress Test) to assess salivary cortisol stress responses. The major finding of this study indicates that DNA_M in a biologically relevant region of NR3C1-1F moderates the specific direction of HPA-axis dysregulation (hypo- vs. hyperreactivity) in adults exposed to moderate-severe CT. Those trauma survivors with increased NR3C1-1F DNA_M displayed, on average, 10.4 nmol/l (62.3%) higher peak cortisol levels in response to the TSST compared to those with low DNA_M. In contrast, unexposed and mildly-moderately exposed individuals displayed moderately sized cortisol stress responses irrespective of NR3C1-1F DNA_M. Contrary to some prior work, however, our data provides no evidence for a direct association of CT and NR3C1-1F DNA_M status. According to this study, epigenetic changes of NR3C1-1F may provide a more in-depth understanding of the highly variable neuroendocrine and pathological sequelae of CT.

Maternal prenatal stress and infant DNA methylation: A systematic review

Maternal prenatal stress has been linked to a variety of infant postnatal outcomes, partially through alterations in fetal HPA axis functioning; yet the underlying pathobiology remains elusive. Current literature posits DNA methylation as a candidate mechanism through which maternal prenatal stress can influence fetal HPA axis functioning. The goal of this systematic review was to summarize the literature examining the associations among maternal prenatal stress, DNA methylation of commonly studied HPA axis candidate genes, and infant HPA axis functioning. Results from the review provided evidence for a link between various maternal prenatal stressors, NR3C1 methylation, and infant stress reactivity, but findings among other genes were limited, with mixed results. An original study quality review tool revealed that a majority of studies in the review are adequate, and emphasizes the need for future research to consider study quality when interpreting research findings.

Epigenetic Effect of Environmental Factors on Neurodevelopmenal Disorders

Epigenetics is an important mechanism of gene regulation that is dependent on the chromatin structure, which is determined by the epigenetic chemical modification of DNA and histone proteins. It is known that the failure of epigenetic mechanisms causes congenital neurodevelopmental disorders (NDs), and that early life exposure to mental stress and endocrine disrupting chemicals, such as phthalates, bisphenol A, and tobacco, can change epigenetic mechanism and gene expression in the brain and cause NDs. Moreover, environmentally induced epigenetic changes are not erased during gametogenesis and are transmitted to subsequent generations, leading to changes in behavior phenotypes. However, epigenetics has a reversible nature because it is based on the addition or removal of chemical residues, and thus the original epigenetic status may be restored. Indeed, several drugs used for mental disorders and NDs restore the epigenetic state and gene expression. Improved epigenetic understanding of NDs will provide important clues for the development of new drugs that take advantage of epigenetic reversibility.

The impact of prenatal insults on the human placental epigenome: A systematic review

The placenta is the first human organ to reach full development during pregnancy. It serves as a barrier but also as an interchange surface. Epigenetic changes observed in placental tissue may reflect intrauterine insults while also pointing to physiological pathways altered under exposure to such environmental threats. By means of a systematic search of the literature, 39 papers assessing human placental epigenetic signatures in association with either (i) psychosocial stress, (ii) maternal psychopathology, (iii) maternal smoking during pregnancy, and (iv) exposure to environmental pollutants, were identified. Their findings revealed placental tissue as a unique source of epigenetic variability that does not correlate with epigenetic patterns observed in maternal or newborn blood, tissues which are typically analyzed regarding prenatal stress. Studies regarding prenatal stress and psychopathology during pregnancy were scarce and exploratory in nature revealing inconsistent findings. Of note, there was a marked tendency towards placental hypomethylation in studies assessing either tobacco use during pregnancy or exposure to environmental pollutants suggesting the interaction between contaminant-derived metabolites and epigenetic machinery. This review highlights the need for further prospective longitudinal studies assessing long-term health effects of placental epigenetic signatures derived from exposure to several prenatal stressors.

Prenatal Stress, Glucocorticoids, and Developmental Programming of the Stress Response

The early environment has a major impact on the developing embryo, fetus, and infant. Parental adversity (maternal and paternal) and glucocorticoid exposure before conception and during pregnancy have profound effects on the development and subsequent function of the hypothalamic-pituitary-adrenal axis and related behaviors. These effects are species-, sex-, and age-specific and depend on the timing and duration of exposure. The impact of these early exposures can extend across multiple generations, via both the maternal and paternal lineage, and recent studies have begun to determine the mechanisms by which this occurs. Improved knowledge of the mechanisms by which adversity and glucocorticoids program stress systems will allow development of strategies to ameliorate and/or reverse these long-term effects.

Translational Geroscience: From invertebrate models to companion animal and human interventions

Translational geroscience is an interdisciplinary field descended from basic gerontology that seeks to identify, validate, and clinically apply interventions to maximize healthy, disease-free lifespan. In this review, we describe a research pipeline for the identification and validation of lifespan extending interventions. Beginning in invertebrate model systems, interventions are discovered and then characterized using other invertebrate model systems (evolutionary translation), models of genetic diversity, and disease models. Vertebrate model systems, particularly mice, can then be utilized to validate interventions in mammalian systems. Collaborative, multi-site efforts, like the Interventions Testing Program (ITP), provide a key resource to assess intervention robustness in genetically diverse mice. Mouse disease models provide a tool to understand the broader utility of longevity interventions. Beyond mouse models, we advocate for studies in companion pets. The Dog Aging Project is an exciting example of translating research in dogs, both to develop a model system and to extend their healthy lifespan as a goal in itself. Finally, we discuss proposed and ongoing intervention studies in humans, unmet needs for validating interventions in humans, and speculate on how differences in survival among human populations may influence intervention efficacy.

The impact of psychological distress during pregnancy on the developing fetus: biological mechanisms and the potential benefits of mindfulness interventions

The in utero environment plays an essential role in shaping future growth and development. Psychological distress during pregnancy has been shown to perturb the delicate physiological milieu of pregnancy, and has been associated with negative repercussions in the offspring, including adverse birth outcomes, long-term defects in cognitive development, behavioral problems during childhood and high baseline levels of stress-related hormones. Fetal epigenetic programming, involving epigenetic processes, may help explain the link between maternal prenatal stress and its negative effects on the child. Given the potential long-term effects of early-life stress on a child's health, it is crucial to minimize maternal distress during pregnancy. A number of recent studies have examined the usefulness of mindfulness-based programs to reduce prenatal psychological stress and improve maternal psychological health, and these are reviewed here. Overall, the findings are promising, but more research is needed with large studies using randomized controlled study designs. It remains unclear whether or not such interventions could also improve child health outcomes, and whether these changes are modulated at the epigenetic level during fetal development. Further studies in this area are needed.

Newborn genome-wide DNA methylation in association with pregnancy anxiety reveals a potential role for GABBR1

BACKGROUND

There is increasing evidence for the role of prenatal stress in shaping offspring DNA methylation and disease susceptibility. In the current study, we aimed to identify genes and pathways associated with pregnancy anxiety using a genome-wide DNA methylation approach.

METHODS

We selected 22 versus 23 newborns from our Prenatal Early Life Stress (PELS) cohort, exposed to the lowest or highest degree of maternal pregnancy anxiety, respectively. Cord blood genome-wide DNA methylation was assayed using the HumanMethylation450 BeadChip (HM450, n = 45) and candidate gene methylation using EpiTYPER (n = 80). Cortisol levels were measured at 2, 4, and 12 months of age to test infant stress system (re)activity.

RESULTS

Data showed ten differentially methylated regions (DMR) when comparing newborns exposed to low versus high pregnancy anxiety scores. We validated a top DMR in the GABA-B receptor subunit 1 gene (GABBR1) revealing the association with pregnancy anxiety particularly in male newborns (most significant CpG Pearson R = 0.517, p = 0.002; average methylation Pearson R = 0.332, p = 0.039). Cord blood GABBR1 methylation was associated with infant cortisol levels in response to a routine vaccination at 4 months old.

CONCLUSIONS

In conclusion, our results show that pregnancy anxiety is associated with differential DNA methylation patterns in newborns and that our candidate gene GABBR1 is associated with infant hypothalamic-pituitary-adrenal axis response to a stressor. Our findings reveal a potential role for GABBR1 methylation in association with stress and provide grounds for further research.

Maternal distress in late pregnancy alters obstetric outcomes and the expression of genes important for placental glucocorticoid signalling

The experience of maternal distress in pregnancy is often linked with poorer obstetric outcomes for women as well as adverse outcomes for offspring. Alterations in placental glucocorticoid signalling and subsequent increased fetal exposure to cortisol have been suggested to underlie this relationship. In the current study, 121 pregnant women completed the Perceived Stress Scale, State Trait Anxiety Inventory and Edinburgh Postnatal Depression Scale in the third trimester of pregnancy. Placental samples were collected after delivery. Maternal history of psychiatric illness and miscarriage were significant predictors of poorer mental health in pregnancy. Higher anxiety was associated with an increase in women delivering via elective Caesarean Section, and an increase in bottle-feeding. Birth temperature was mildly reduced among infants of women with high levels of depressive symptomology. Babies of mothers who scored high in all stress (cumulative distress) measures had reduced 5-min Apgar scores. High cumulative distress reduced the expression of placental HSD11B2 mRNA and increased the expression of placental NR3C1 mRNA. These data support a role for prenatal distress as a risk factor for altered obstetric outcomes. The alterations in placental gene expression support a role for altered placental glucocorticoid signalling in the relationship between maternal prenatal distress and adverse outcomes.

Developmental origins of the human hypothalamic-pituitary-adrenal axis

INTRODUCTION

The developmental origins of disease or fetal programming model predicts that intrauterine exposures have life long consequences for physical and psychological health. Prenatal programming of the fetal hypothalamic-pituitary-adrenal (HPA) axis is proposed as a primary mechanism by which early experiences are linked to later disease risk. Areas covered: This review describes the development of the fetal HPA axis, which is determined by an intricately timed cascade of endocrine events during gestation and is regulated by an integrated maternal-placental-fetal steroidogenic unit. Mechanisms by which stress-induced elevations in hormones of maternal, fetal, or placental origin influence the structure and function of the emerging fetal HPA axis are discussed. Recent prospective studies documenting persisting associations between prenatal stress exposures and altered postnatal HPA axis function are summarized, with effects observed beginning in infancy into adulthood. Expert commentary: The results of these studies are synthesized, and potential moderating factors are discussed. Promising areas of further research highlighted include epigenetic mechanisms and interactions between pre and postnatal influences.

Maternal depression and anxiety and fetal-neonatal growth

OBJECTIVE

Maternal depression and anxiety have been found to negatively affect fetal and neonatal growth. However, the independent effects of maternal depression and anxiety on fetal-neonatal growth outcomes and trajectories remain unclear. This study aimed to analyze simultaneously the effects of maternal prenatal depression and anxiety on (1) neonatal growth outcomes, and (2), on fetal-neonatal growth trajectories, from the 2nd trimester of pregnancy to childbirth.

METHODS

A sample of 172 women was recruited and completed self-reported measures of depression and anxiety during the 2nd and 3rd trimesters of pregnancy, and at childbirth. Fetal and neonatal biometrical data were collected from clinical reports at the same assessment moments.

RESULTS

Neonates of prenatally anxious mothers showed lower weight (p=0.006), length (p=0.025), and ponderal index (p=0.049) at birth than neonates of prenatally non-anxious mothers. Moreover, fetuses-neonates of high-anxiety mothers showed a lower increase of weight from the 2nd trimester of pregnancy to childbirth than fetuses-neonates of low-anxiety mothers (p<0.001). Considering maternal depression and anxiety simultaneously, only the effect of maternal anxiety was found on these markers of fetal-neonatal growth outcomes and trajectories.

CONCLUSION

This study demonstrates the independent longitudinal effect of maternal anxiety on major markers of fetal-neonatal growth outcomes and trajectories, simultaneously considering the effect of maternal depression and anxiety.

Neurodevelopmental Disorders and Environmental Toxicants: Epigenetics as an Underlying Mechanism

The increasing prevalence of neurodevelopmental disorders, especially autism spectrum disorders (ASD) and attention deficit hyperactivity disorder (ADHD), calls for more research into the identification of etiologic and risk factors. The Developmental Origin of Health and Disease (DOHaD) hypothesizes that the environment during fetal and childhood development affects the risk for many chronic diseases in later stages of life, including neurodevelopmental disorders. Epigenetics, a term describing mechanisms that cause changes in the chromosome state without affecting DNA sequences, is suggested to be the underlying mechanism, according to the DOHaD hypothesis. Moreover, many neurodevelopmental disorders are also related to epigenetic abnormalities. Experimental and epidemiological studies suggest that exposure to prenatal environmental toxicants is associated with neurodevelopmental disorders. In addition, there is also evidence that environmental toxicants can result in epigenetic alterations, notably DNA methylation. In this review, we first focus on the relationship between neurodevelopmental disorders and environmental toxicants, in particular maternal smoking, plastic-derived chemicals (bisphenol A and phthalates), persistent organic pollutants, and heavy metals. We then review studies showing the epigenetic effects of those environmental factors in humans that may affect normal neurodevelopment.

Intergenerational Transmission of Maternal Childhood Maltreatment Exposure: Implications for Fetal Brain Development

OBJECTIVE

Growing evidence suggests the deleterious consequences of exposure to childhood maltreatment (CM) not only might endure over the exposed individual's lifespan but also might be transmitted across generations. The time windows, mechanisms, and targets of such intergenerational transmission are poorly understood. The prevailing paradigm posits that mother-to-child transmission of the effects of maternal CM likely occurs after her child's birth. The authors seek to extend this paradigm and advance a transdisciplinary framework that integrates the concepts of biological embedding of life experiences and fetal origins of health and disease risk.

METHOD

The authors posit that the period of embryonic and fetal life represents a particularly sensitive time for intergenerational transmission; that the developing brain represents a target of particular interest; and that stress-sensitive maternal-placental-fetal biological (endocrine, immune) pathways represent leading candidate mechanisms of interest.

RESULTS

The plausibility of this model is supported by theoretical considerations and empirical findings in humans and animals. The authors synthesize several research areas and identify important knowledge gaps that might warrant further study.

CONCLUSION

The scientific and public health relevance of this effort relates to achieving a better understanding of the "when," "what," and "how" of intergenerational transmission of CM, with implications for early identification of risk, prevention, and intervention.

Epigenetic programming by stress and glucocorticoids along the human lifespan

Psychosocial stress triggers a set of behavioral, neural, hormonal, and molecular responses that can be a driving force for survival when adaptive and time-limited, but may also contribute to a host of disease states if dysregulated or chronic. The beneficial or detrimental effects of stress are largely mediated by the hypothalamic-pituitary axis, a highly conserved neurohormonal cascade that culminates in systemic secretion of glucocorticoids. Glucocorticoids activate the glucocorticoid receptor, a ubiquitous nuclear receptor that not only causes widespread changes in transcriptional programs, but also induces lasting epigenetic modifications in many target tissues. While the epigenome remains sensitive to stressors throughout life, we propose two key principles that may govern the epigenetics of stress and glucocorticoids along the lifespan: first, the presence of distinct life periods, during which the epigenome shows heightened plasticity to stress exposure, such as in early development and at advanced age; and, second, the potential of stress-induced epigenetic changes to accumulate throughout life both in select chromatin regions and at the genome-wide level. These principles have important clinical and translational implications, and they show striking parallels with the existence of sensitive developmental periods and the cumulative impact of stressful experiences on the development of stress-related phenotypes. We hope that this conceptual mechanistic framework will stimulate fruitful research that aims at unraveling the molecular pathways through which our life stories sculpt genomic function to contribute to complex behavioral and somatic phenotypes.

[Epigenetic modifications in children associated with maternal emotional stress during pregnancy]

Besides typical physical and hormonal changes during pregnancy, this life period is often associated with an increased emotional and mental stress for women. For the child, the time in utero is regarded as a critical developmental period since adverse stimuli during pregnancy can have lasting consequences for the fetal and postnatal health and development. Thus, prenatal depression, anxiety and stress are considered as risk factors for developmental delay, emotional and behavioral problems. Epigenetic modifications, especially modifications in DNA methylation, are discussed as a possible biological mechanism that could explain the association between prenatal emotional stress and altered developmental and health outcomes of the child. This review summarizes evidence for DNA methylation changes related to prenatal emotional stress from studies with a candidate-gene approach as well as epigenome-wide association studies. Problematic issues are discussed and recommendations for future research are presented.

Epigenetics and Health Disparities

PURPOSE OF REVIEW

African Americans disproportionately suffer from leading causes of morbidity and mortality including cardiovascular disease (CVD), cancer, and preterm birth. Disparities can arise from multiple social and environmental exposures, but how the human body responds to these exposures to result in pathophysiologic states is incompletely understood.

RECENT FINDINGS

Epigenetic mechanisms, particularly DNA methylation, can be altered in response to exposures such as air pollution, psychosocial stress, and smoking. Each of these exposures has been linked to the above health states (CVD, cancer, and preterm birth) with striking racial disparities in exposure levels. DNA methylation patterns have also been shown to be associated with each of these health outcomes.

SUMMARY

Whether DNA methylation mediates exposure-disease relationships and can help explain racial disparities in health is not known. However, because many environmental and adverse social exposures disproportionately affect minorities, understanding the role that epigenetics plays in the human response to these exposures that often result in disease, is critical to reducing disparities in morbidity and mortality.

Prenatal Depression Risk Factors, Developmental Effects and Interventions: A Review

This narrative review based on a literature search in PubMed and PsycInfo on the two terms prenatal and antenatal depression includes empirical studies, reviews and meta-analyses that have been published during the last 5 years on risk factors, developmental effects and interventions for prenatal depression. Risk factor studies that met criteria feature demographic measures (lower socioeconomic status, less education, non-marital status, non-employment, less social support and health locus of control, unintended pregnancy, partner violence and history of child abuse) and physiological variables (cortisol, amylase, and pro-inflammatory cytokines and intrauterine artery resistance). The negative effects include postpartum depression, paternal depression, and prematurity and low birth weight. Negative effects on infants include greater right frontal EEG, amygdala connectivity, cortical thinning and more difficult temperament. In childhood, externalizing and internalizing problems have been reported. The data on prenatal antidepressants (specifically SSRIs) reveal negative effects including internalizing problems as well as a greater risk for autism spectrum disorder. Prenatal interventions that have been effective include interpersonal psychotherapy, peer support, massage therapy, yoga, tai chi, and aerobic exercise. Potential underlying mechanisms are discussed as well as methodological limitations including homogeneity of samples and lack of randomization to intervention groups. Despite these limitations, the literature highlights the need for prenatal depression screening and intervention.