Associations between maternal prenatal stress, methylation changes in IGF1 and IGF2, and birth weight

Epigenetic Responses to Nonchemical Stressors: Potential Molecular Links to Perinatal Health Outcomes

PURPOSE OF REVIEW

We summarize the recent literature investigating exposure to four nonchemical stressors (financial stress, racism, psychosocial stress, and trauma) and DNA methylation, miRNA expression, and mRNA expression. We also highlight the relationships between these epigenetic changes and six critical perinatal outcomes (preterm birth, low birth weight, preeclampsia, gestational diabetes, childhood allergic disease, and childhood neurocognition).

RECENT FINDINGS

Multiple studies have found financial stress, psychosocial stress, and trauma to be associated with DNA methylation and/or miRNA and mRNA expression. Fewer studies have investigated the effects of racism. The majority of studies assessed epigenetic or genomic changes in maternal blood, cord blood, or placenta. Several studies included multi-OMIC assessments in which DNA methylation and/or miRNA expression were associated with gene expression. There is strong evidence for the role of epigenetics in driving the health outcomes considered. A total of 22 biomarkers, including numerous HPA axis genes, were identified to be epigenetically altered by both stressors and outcomes. Epigenetic changes related to inflammation, the immune and endocrine systems, and cell growth and survival were highlighted across numerous studies. Maternal exposure to nonchemical stressors is associated with epigenetic and/or genomic changes in a tissue-specific manner among inflammatory, immune, endocrine, and cell growth-related pathways, which may act as mediating pathways to perinatal health outcomes. Future research can test the mediating role of the specific biomarkers identified as linked with both stressors and outcomes. Understanding underlying epigenetic mechanisms altered by nonchemical stressors can provide a better understanding of how chemical and nonchemical exposures interact.

Prenatal maternal stress is associated with site-specific and age acceleration changes in maternal and newborn DNA methylation

Prenatal maternal stress has a negative impact on child health but the mechanisms through which maternal stress affects child health are unclear. Epigenetic variation, such as DNA methylation, is a likely mechanistic candidate as DNA methylation is sensitive to environmental insults and can regulate long-term changes in gene expression. We recruited 155 mother-newborn dyads in the Democratic Republic of Congo to investigate the effects of maternal stress on DNA methylation in mothers and newborns. We used four measures of maternal stress to capture a range of stressful experiences: general trauma, sexual trauma, war trauma, and chronic stress. We identified differentially methylated positions (DMPs) associated with general trauma, sexual trauma, and war trauma in both mothers and newborns. No DMPs were associated with chronic stress. Sexual trauma was positively associated with epigenetic age acceleration across several epigenetic clocks in mothers. General trauma and war trauma were positively associated with newborn epigenetic age acceleration using the extrinsic epigenetic age clock. We tested the top DMPs for enrichment of DNase I hypersensitive sites (DHS) and found no enrichment in mothers. In newborns, top DMPs associated with war trauma were enriched for DHS in embryonic and foetal cell types. Finally, one of the top DMPs associated with war trauma in newborns also predicted birthweight, completing the cycle from maternal stress to DNA methylation to newborn health outcome. Our results indicate that maternal stress is associated with site-specific changes in DNAm and epigenetic age acceleration in both mothers and newborns.

The relationship between obesity-related H19DMR methylation and H19 and IGF2 gene expression on offspring growth and body composition

Background and objective

Imprinted genes are important for the offspring development. To assess the relationship between obesity-related H19DMR methylation and H19 and IGF2 gene expression and offspring growth and body composition.

Methods

Thirty-nine overweight/obese and 25 normal weight pregnant women were selected from the "Araraquara Cohort Study" according to their pre-pregnancy BMI. Fetal growth and body composition and newborn growth were assessed, respectively, by ultrasound and anthropometry. The methylation of H19DMR in maternal blood, cord blood, maternal decidua and placental villi tissues was evaluated by methylation-sensitive restriction endonuclease qPCR, and H19 and IGF2 expression by relative real-time PCR quantification. Multiple linear regression models explored the associations of DNA methylation and gene expression with maternal, fetal, and newborn parameters.

Results

H19DMR was less methylated in maternal blood of the overweight/obese group. There were associations of H19DMR methylation in cord blood with centiles of fetal biparietal diameter (BPD) and abdominal subcutaneous fat thickness and newborn head circumference (HC); H19DMR methylation in maternal decidua with fetal occipitofrontal diameter (OFD), HC, and length; H19DMR methylation in placental villi with fetal OFD, HC and abdominal subcutaneous fat thickness and with newborn HC. H19 expression in maternal decidua was associated with fetal BPD and femur length centiles and in placental villi with fetal OFD and subcutaneous arm fat. IGF2 expression in maternal decidua was associated with fetal BPD and in placental villi with fetal OFD.

Conclusion

To our knowledge, this is the first study to demonstrate associations of imprinted genes variations at the maternal-fetal interface of the placenta and in cord blood with fetal body composition, supporting the involvement of epigenetic mechanisms in offspring growth and body composition.

The association between prenatal famine, DNA methylation and mental disorders: a systematic review and meta-analysis

BACKGROUND

Undernutrition in pregnant women is an unfavorable environmental condition that can affect the intrauterine development via epigenetic mechanisms and thus have long-lasting detrimental consequences for the mental health of the offspring later in life. One epigenetic mechanism that has been associated with mental disorders and undernutrition is alterations in DNA methylation. The effect of prenatal undernutrition on the mental health of adult offspring can be analyzed through quasi-experimental studies such as famine studies. The present systematic review and meta-analysis aims to analyze the association between prenatal famine exposure, DNA methylation, and mental disorders in adult offspring. We further investigate whether altered DNA methylation as a result of prenatal famine exposure is prospectively linked to mental disorders.

METHODS

We conducted a systematic search of the databases PubMed and PsycINFO to identify relevant records up to September 2022 on offspring whose mothers experienced famine directly before and/or during pregnancy, examining the impact of prenatal famine exposure on the offspring's DNA methylation and/or mental disorders or symptoms.

RESULTS

The systematic review showed that adults who were prenatally exposed to famine had an increased risk of schizophrenia and depression. Several studies reported an association between prenatal famine exposure and hyper- or hypomethylation of specific genes. The largest number of studies reported differences in DNA methylation of the IGF2 gene. Altered DNA methylation of the DUSP22 gene mediated the association between prenatal famine exposure and schizophrenia in adult offspring. Meta-analysis confirmed the increased risk of schizophrenia following prenatal famine exposure. For DNA methylation, meta-analysis was not suitable due to different microarrays/data processing approaches and/or unavailable data.

CONCLUSION

Prenatal famine exposure is associated with an increased risk of mental disorders and DNA methylation changes. The findings suggest that changes in DNA methylation of genes involved in neuronal, neuroendocrine, and immune processes may be a mechanism that promotes the development of mental disorders such as schizophrenia and depression in adult offspring. Such findings are crucial given that undernutrition has risen worldwide, increasing the risk of famine and thus also of negative effects on mental health.

Epigenetics as a Biomarker for Early-Life Environmental Exposure

PURPOSE OF REVIEW

There is interest in evaluating the developmental origins of health and disease (DOHaD) which emphasizes the role of prenatal and early-life environments on non-communicable health outcomes throughout the life course. The ability to rigorously assess and identify early-life risk factors for later health outcomes, including those with childhood onset, in large population samples is often limited due to measurement challenges such as impractical costs associated with prospective studies with a long follow-up duration, short half-lives for some environmental toxicants, and lack of biomarkers that capture inter-individual differences in biologic response to external environments.

RECENT FINDINGS

Epigenomic patterns, and DNA methylation in particular, have emerged as a potential objective biomarker to address some of these study design and exposure measurement challenges. In this article, we summarize the literature to date on epigenetic changes associated with specific prenatal and early-life exposure domains as well as exposure mixtures in human observational studies and their biomarker potential. Additionally, we highlight evidence for other types of epigenetic patterns to serve as exposure biomarkers. Evidence strongly supports epigenomic biomarkers of exposure that are detectable across the lifespan and across a range of exposure domains. Current and future areas of research in this field seek to expand these lines of evidence to other environmental exposures, to determine their specificity, and to develop predictive algorithms and methylation scores that can be used to evaluate early-life risk factors for health outcomes across the life span.

Impact of chemotherapy during pregnancy on fetal growth

BACKGROUND

Chemotherapy crosses the placenta, however, it remains unclear to what extent it affects fetal growth. The current literature suggests up to 21% of the offspring of women receiving chemotherapy are small for gestational age (SGA, birth weight <10th percentile). Limiting research to birth weights only might misjudge fetal growth restriction (FGR) in this high-risk population with multiple risk factors for impaired fetal growth. Moreover, the role of the duration of chemotherapy and gestational age at initiation of chemotherapy in fetal growth is yet poorly understood.

OBJECTIVE

This retrospective cohort study evaluates fetal growth and neonatal birthweights in pregnant women receiving chemotherapy.

STUDY DESIGN

All pregnant patients, registered by the International Network of Cancer, Infertility and Pregnancy (INCIP), treated with chemotherapy with at least two ultrasounds reporting on fetal growth, were eligible for this study. Duration and gestational age at initiation of chemotherapy were our major determinants, followed by cancer type and stage, maternal characteristics (parity, BMI, ethnicity hypertension, and diabetes) and individual cytotoxic agents (anthracycline, taxanes, and platinum). Fetal growth outcomes were described using the following mutually exclusive groups (1) FGR, based on a Delphi consensus (2016); (2) "low risk SGA" (birth weight below the 10th percentile), but an estimated growth above the 10th percentile; (3) "fetal growth disturbance", which did not meet all FGR criteria; (4) "non-FGR". Obstetric and oncological characteristics were compared between the growth impaired groups and non-FGR group. We calculated estimated fetal weight (EFW) according to Hadlock's formula (1991) and birth weight percentile according to Nicolaides (2018). We used univariable and multivariable regression, and linear mixed effect models to investigate the effect of duration and gestational age at initiation of chemotherapy on birth weight, and fetal growth, respectively.

RESULTS

We included 201 patients, diagnosed with cancer between March 2000 and March 2020. Most patients were diagnosed with breast cancer (n = 132, 66%). Regimens included anthracyclines (n = 121, 60%), (anthracyclines and) taxanes (n = 45, 22%) and platinum (n = 35, 17%). Fetal growth abnormalities were detected in 75 pregnancies: 43 (21%) FGR, 10 (5%) low risk SGA and 22 (8.5%) fetal growth disturbance. Chemotherapy prior to 20 weeks of gestation (47% vs. 25%, p = .04) and poor maternal gestational weight gain (median percentile 15 (range 0-97) vs. 8 (0-84), p = .03) were more frequent in the FGR group compared to the non-FGR group, whereas no difference was seen for specific chemotherapy or cancer types. Univariable regression identified gestational weight gain, hypertension, systemic disease, parity, neonatal sex and maternal BMI as confounders for birth weight percentiles. Multivariable regression revealed that each additional week of chemotherapy was associated with lower birth weight percentiles (-1.06; 95%CI -2.01; -0.04; p = .04), and that later initiation of chemotherapy was associated with an increase in birth weight percentile (1.10 per week; 95%CI 0.26; 1.95; p = .01). Each additional week of chemotherapy was associated with lower EFW and abdominal circumference (AC) percentiles (-1.77; 95%CI -2.21; -1.34, p < .001; -1.64; 95%CI -1.96; -1.32, p < .001, respectively).

CONCLUSIONS

This study demonstrates that FGR is common after chemotherapy in pregnancy, and that the duration of chemotherapy has a negative impact. Sonographic follow-up of fetal growth and well-being is recommended.

Fear Stress During Pregnancy Affects Placental m6A-Modifying Enzyme Expression and Epigenetic Modification Levels

As the hub connecting mother and offspring, the placenta’s normal development is vital for fetal growth. Fear stress can cause some structural alterations in the placenta and affect placental development and function. N6-methyladenosine (m6A) is the most common mRNA modification and is involved in regulating the development of the placenta and embryo. There are no reports on the potential role of m6A modification in placental damage caused by fear stress during pregnancy. In this study, we demonstrated that fear stress during pregnancy increases the levels of methylated enzymes (METTL3, METTL14, and WTAP), decreases the levels of demethylase FTO, and increases the overall methylation levels in the placenta of pregnant rats. MeRIP-seq data analysis revealed 22,010 m6A peaks associated with 12,219 genes in the placenta of the model and 21,060 m6A peaks associated with 11,730 genes in the placenta of the control. The peaks were mainly concentrated in the coding region and the 3ʹ untranslated region. In addition, 50 genes with abnormal modification and expression (double aberrant genes) were screened out by combining MeRIP-seq and RNA-seq data. Mefv, Erbb2, and Cgas were selected from 50 double aberrant genes, and MeRIP-qPCR and real-time quantitative polymerase chain reaction were used to verify their modification and expression levels. Our findings suggest that m6A modifications play an important role in placental dysfunction induced by fear stress during pregnancy.

The socioeconomic landscape of the exposome during pregnancy

BACKGROUND

While socioeconomic position (SEP) is consistently related to pregnancy and birth outcome disparities, relevant biological mechanisms are manifold, thus necessitating more comprehensive characterization of SEP-exposome associations during pregnancy.

OBJECTIVES

We implemented an exposomic approach to systematically characterize the socioeconomic landscape of prenatal exposures in a setting where social segregation was less distinct in a hypotheses-generating manner.

METHODS

We described the correlation structure of 134 prenatal exogenous and endogenous sources (e.g., micronutrients, hormones, immunomodulatory metabolites, environmental pollutants) collected in a diverse, population-representative, urban, high-income longitudinal mother-offspring cohort (N = 1341; 2009-2011). We examined the associations between maternal, paternal, household, and areal level SEP indicators and 134 exposures using multiple regressions adjusted for precision variables, as well as potential effect measure modification by ethnicity and nativity. Finally, we generated summary SEP indices using Multiple Correspondence Analysis to further explore possible curved relationships.

RESULTS

Individual and household SEP were associated with anthropometric/adiposity measures, folate, omega-3 fatty acids, insulin-like growth factor-II, fasting glucose, and neopterin, an inflammatory marker. We observed paternal education was more strongly and consistently related to maternal exposures than maternal education. This was most apparent amongst couples discordant on education. Analyses revealed additional non-linear associations between areal composite SEP and particulate matter. Environmental contaminants (e.g., per- and polyfluoroalkyl substances) and micronutrients (e.g., folate and copper) showed opposing associations by ethnicity and nativity, respectively.

DISCUSSION

SEP-exposome relationships are complex, non-linear, and context specific. Our findings reinforce the potential role of paternal contributions and context-specific modifiers of associations, such as between ethnicity and maternal diet-related exposures. Despite weak presumed areal clustering of individual exposures in our context, our approach reinforces subtle non-linearities in areal-level exposures.

Gestational exposure to neighborhood police-reported crime and early childhood blood pressure in Durham, NC

Gestational exposure to police-reported crime is associated with adverse birth outcomes, but no previous research has evaluated the effects of gestational crime exposure on early childhood health or attempted to disentangle the health effects of neighborhood crime from the effects of neighborhood policing. Using data from 672 Newborn Epigenetics Study participants, we evaluate the effects of gestational exposure to violent crime and racialized drug policing on early childhood blood pressure. We demonstrate that violence and drug policing are consistently associated with increased blood pressure among children born to Black participants but not White or Latinx participants.

Understanding Health Inequalities Through the Lens of Social Epigenetics

Longstanding racial/ethnic inequalities in morbidity and mortality persist in the United States. Although the determinants of health inequalities are complex, social and structural factors produced by inequitable and racialized systems are recognized as contributing sources. Social epigenetics is an emerging area of research that aims to uncover biological pathways through which social experiences affect health outcomes. A growing body of literature links adverse social exposures to epigenetic mechanisms, namely DNA methylation, offering a plausible pathway through which health inequalities may arise. This review provides an overview of social epigenetics and highlights existing literature linking social exposures—i.e., psychosocial stressors, racism, discrimination, socioeconomic position, and neighborhood social environment—to DNA methylation in humans.We conclude with a discussion of social epigenetics as a mechanistic link to health inequalities and provide suggestions for future social epigenetics research on health inequalities.

A critical biocultural approach to early growth in the United States

OBJECTIVES

A critical biocultural anthropology seeks to link perspectives from social theory and ethnography to human biology. In the United States (U.S.), multiple forms of structural inequalities affect early growth, including racism and poverty. The goal of this paper is to test the effects of social inequalities on birth weight and later height in the U.S. National Health and Nutrition Survey (NHANES), and to contextualize potential pathways of embodiment that link social structure and biology.

METHODS

This study used data from 8392 children ages 0-5 years from the 2005 to 2016 NHANES. Reported birth weight and measured length/height (converted to height-for-age z-scores) were used as outcome variables, while various measures of socioeconomic status and the NHANES-defined race and ethnicity categories were operationalized as social variables. Structural equation modeling (SEM) was chosen to represent the data.

RESULTS

The final model represented an excellent fit to the data. Higher birth weights were associated with higher height-for-age z-scores. The Black racial category was associated with lower birth weight and higher height-for-age z-score, while the "Other" racial category was also associated with lower birth weight. The socioeconomic status factor variable was significantly associated with birth weight and height-for-age z-scores. There were also multiple indirect effects of social variables on height-for-age z-scores mediated via their effects on birth weight.

CONCLUSIONS

Inequalities in race and socioeconomic status persist in birth weight and early childhood stature in the U.S. These findings can be contextualized by a critical biocultural anthropology that integrates lived experiences and pathways of embodiment.

The effect of early life events on glucose levels in first-episode psychosis

First episode of psychosis (FEP) patients display a wide variety of metabolic disturbances at onset, which might underlie these patients' increased morbidity and early mortality. Glycemic abnormalities have been previously related to pharmacological agents; however, recent research highlights the impact of early life events. Birth weight (BW), an indirect marker of the fetal environment, has been related to glucose abnormalities in the general population over time. We aim to evaluate if BW correlates with glucose values in a sample of FEP patients treated with different antipsychotics. Two hundred and thirty-six patients were included and evaluated for clinical and metabolic variables at baseline and at 2, 6, 12, and 24 months of follow-up. Pearson correlations and linear mixed model analysis were conducted to analyze the data. Antipsychotic treatment was grouped due to its metabolic risk profile. In our sample of FEP patients, BW was negatively correlated with glucose values at 24 months of follow-up [r=-0.167, p=0.037]. BW showed a trend towards significance in the association with glucose values over the 24-month period (F=3.22; p=0.073) despite other confounders such as age, time, sex, body mass index, antipsychotic type, and chlorpromazine dosage. This finding suggests that BW is involved in the evolution of glucose values over time in a cohort of patients with an FEP, independently of the type of pharmacological agent used in treatment. Our results highlight the importance of early life events in the later metabolic outcome of patients.

High glucose increases IGF-2/H19 expression by changing DNA methylation in HTR8/SVneo trophoblast cells

INTRODUCTION

Gestational diabetes mellitus (GDM) is associated with many adverse outcomes of pregnancy, especially macrosomia. The aim of our study was to verify whether high glucose concentrations change the methylation levels of the insulin-like growth factor-2 (IGF-2)/H19 gene promoters to increase the expression of IGF-2, a key gene in fetal growth regulation.

METHODS

HTR8/SVneo cells were used to establish a cell model of intrauterine hyperglycemia in pregnant women with GDM. The RNA expression levels of the IGF-2/H19 genes and the methylation levels of the IGF-2/H19 gene promoter regions were measured. Methylated and unmethylated IGF-2/H19 gene promoter plasmids were transfected into HTR8/SVneo cells.

RESULTS

Among the five groups of cells, the RNA levels of IGF-2 and H19 were lowest in the 5-mM (physiological blood glucose level) group, which was statistically significant (all P < 0.05). Compared with those in the 5-mM group, two cytosine-phosphate-guanine (CpG) sites in the promoter region of the IGF-2 gene and twelve CpG sites in the promoter region of the H19 gene had statistically significant changes in methylation levels (all P < 0.05). Additionally, luciferase activity was significantly higher in cells transfected with the methylated H19 gene promoter plasmid than in control cells transfected with the unmethylated plasmid (P < 0.01), while the methylated IGF-2 gene promoter plasmid produced lower luciferase activity than the unmethylated plasmid (P < 0.01).

DISCUSSION

High glucose concentrations may increase IGF-2/H19 expression by changing the methylation levels of the IGF-2 and H19 gene promoters.

Prenatal exposure to polycyclic aromatic hydrocarbons could increase the risk of low birth weight by affecting the DNA methylation states in a Chinese cohort

Polycyclic aromatic hydrocarbons (PAHs), as a kind of endocrine disruptors, can enter the fetus body cross the placental barrier from prenatal PAHs exposure to cause adverse birth outcomes. However, it is controversial association between prenatal PAHs exposure and low birth weight (LBW) of their infants. So the present study aimed to estimate the effects of prenatal PAHs exposure during the pregnancy on the risk of LBW in a Chinese cohort through modifying the DNA methylation states. A longitudinal prospective study with 407 pregnant women was established from May to October 2019. The prenatal PAHs exposure during the pregnancy was assessed using the internal dose such as the PAHs metabolites and PAH-DNA adducts in the umbilical cord blood. The methylation levels of genomic DNA and growth-related genes (IGF1 and IGF2) were assessed, while the expressions of these genes were both determined by RT-PCR and Elisa methods. The growth outcomes and relevant Z-scores were recorded at birth. The correlations between the DNA methylation status and concentrations of PAHs, expression levels of growth-related genes and body weight/WAZ were investigated as the measures. According to the PAH-DNA adducts, the subjects were divided into two groups: PAHs-exposed group (PAH-DNA adducts>0, n = 55) and non-exposed group (PAH-DNA adducts = 0, n = 352). Compared with the non-exposed group, it displayed marked decreased birth weight, and increased concentrations of PAHs and DNA methylation levels of the global genomic, IGF1 and IGF2 with their lower expressions in the PAHs-exposed group. These hypermethylation (global genomic, CpG14 and CpG15 of IGF1, and CpG14 of IGF2) were positively correlated with the contents of PAHs in the umbilical cord blood, and negatively correlated with the growth outcomes and their expressions. Totally, prenatal PAHs exposures may contribute to an increased risk of LBW of their infants by modulating the DNA methylation states of genomic DNA and growth-related genes (IGF1 and IGF2) in the umbilical cord blood, which could provide the prenatal prevention of PAHs exposure from possible environmental media except from the occupation and tobacco usage to ensure the health of their infants.

Fifteen years' experience with methylphenidate for attention-deficit disorder during pregnancy: Effects on birth weight, Apgar score and congenital malformation rates

BACKGROUND

Methylphenidate (MPD) is increasingly prescribed to fertile women with Attention-Deficit Disorder (AD(H)D), with or without hyperactivity, despite advice for discontinuation during pregnancy. Few studies report on results concerning safety after methylphenidate exposure during pregnancy for the offspring.

AIM

Safety for the offspring of exposure to MPD during pregnancy.

METHODS

This is an observational retrospective cohort study in a population of pregnant women and their offspring, treated with MPD for ADHD in the Psychiatry-Gynaecology-Pediatrics outpatient clinic between 1 January 2005 and 1 June 2020 at Isala hospital. The primary endpoints were birth weight and Apgar score in offspring exposed to MPD during pregnancy, compared to offspring unexposed to MPD. Birth weight was analysed using linear mixed model analysis. Apgar score and (secondary endpoint) neonatal malformations, at 20 week ultrasound, were analysed using basic univariate statistical analysis.

RESULTS

MPD continuation, compared to discontinuation, was associated with higher neonatal birth weight (p = 0.049), but lost statistical significance after incorporating covariates (p = 0.079). There were no significant differences in Apgar scores and congenital malformations between neonates exposed and unexposed to MPD.

CONCLUSIONS

MPD does not seem to affect birth weight, Apgar score and the frequency of neonatal malformations at the 20 week ultrasound.

Health repercussions of environmental exposure to lead: Methylation perspective

Lead (Pb) exposure has been a major public health concern for a long time now due to its permanent adverse effects on the human body. The process of lead toxicity has still not been fully understood, but recent advances in Omics technology have enabled researchers to evaluate lead-mediated alterations at the epigenome-wide level. DNA methylation is one of the widely studied and well-understood epigenetic modifications. Pb has demonstrated its ability to induce not just acute deleterious health consequences but also alters the epi-genome such that the disease manifestation happens much later in life as supported by Barkers Hypothesis of the developmental origin of health and diseases. Furthermore, these alterations are passed on to the next generation. Based on previous in-vivo, in-vitro, and human studies, this review provides an insight into the role of Pb in the development of several human disorders.

Methylation of Imprinted Genes in Sperm DNA Correlated to Urinary Polycyclic Aromatic Hydrocarbons (PAHs) Exposure Levels in Reproductive-Aged Men and the Birth Outcomes of the Offspring

Polycyclic aromatic hydrocarbons (PAHs) are known environmental pollutants. Studies are very limited regarding the impacts of paternal PAHs exposure on birth outcomes as well as the underpinning mechanisms in human. In this study, 302 reproductive-aged males (22-46 years old) were enrolled and demographic informatics data were obtained by questionnaires. The levels of urinary hydroxylated PAHs (OH-PAHs) were assessed by ultra-high performance liquid chromatography-tandem mass spectrometry; and methylation levels of the imprinting genes H19, Meg3, and Peg3 of sperm DNA were evaluated via bisulfite pyrosequencing. The analysis of the correlation between OH-PAHs levels and methylation levels of imprinting genes showed that OH-PAHs are correlated with some CpG sites in H19, Peg3, and Meg3. To further investigate an association of urinary OH-PAHs with birth outcomes, follow-up study of wives of these subjects has been performed for 1-3 years. As the result, a total of 157 babies were born. The birth outcomes parameters including birth weight (BW), length (BL), and ponderal index (PI) were recorded. The further analysis of generalized estimating equation indicated a negative correlation between urinary total OH-PAHs levels and newborn BW (β = -0.081, p = 0.020); but this association has not been found for BL and PI. Furthermore, a logistic regression analysis was employed for examining associations of the methylation of imprinting genes with birth outcomes parameters, which indicated a negative correlation between BW and H19, namely, each unit percent (%) elevation in methylation of H19 (but not Peg3 and Meg3) was significantly associated with a 0.135 g reduction of BW (β = -0.135; 95% CI 0.781-0.978). Putting together, these results show that paternal non-occupational environmental exposure to PAHs is associated with newborn BW. And imprinting gene H19 methylation may be involved in the underlying mechanisms. This study in human population adds a support for previous animal study and implies that environmental impact on the offspring through paternal pathway.

[Antipsychotics during pregnancy: a systematic review]

BACKGROUND

The benefits and risks of treatment with antipsychotics during pregnancy must be weighed up carefully and individually because antipsychotics can penetrate the placental barrier and prescription is off-label.

OBJECTIVE

Evaluation of the risks and benefits of administering antipsychotics during pregnancy or for women who wish to become pregnant regarding teratogenic effects, risk of fetal death and stillbirths, perinatal complications, persisting postnatal impairments or disorders and gestational diabetes.

METHODS

A systematic review of the literature is provided to aid the selection of psychotropic drugs during pregnancy and in determining whether to begin, continue or switch an antipsychotic treatment during pregnancy.

RESULTS

Large, well-designed and controlled studies are missing; however, most studies suggest that the group of antipsychotics seem to be safe in terms of teratogenicity during pregnancy, at least in monotherapy.

CONCLUSION

Treating mental illnesses during pregnancy requires an individual assessment of the benefits and risks. The risk of an untreated mental illness versus the benefit of a suitable treatment with antipsychotics and the potential harm to the infant must be evaluated. If certain rules are observed and a suitable antipsychotic is selected the risk to the newborn child and/or mother during pregnancy can be minimized, however, a decision about subsequent medication can only be indirectly made from the results of this study.

DNA Methylation Signature for EZH2 Functionally Classifies Sequence Variants in Three PRC2 Complex Genes

Weaver syndrome (WS), an overgrowth/intellectual disability syndrome (OGID), is caused by pathogenic variants in the histone methyltransferase EZH2, which encodes a core component of the Polycomb repressive complex-2 (PRC2). Using genome-wide DNA methylation (DNAm) data for 187 individuals with OGID and 969 control subjects, we show that pathogenic variants in EZH2 generate a highly specific and sensitive DNAm signature reflecting the phenotype of WS. This signature can be used to distinguish loss-of-function from gain-of-function missense variants and to detect somatic mosaicism. We also show that the signature can accurately classify sequence variants in EED and SUZ12, which encode two other core components of PRC2, and predict the presence of pathogenic variants in undiagnosed individuals with OGID. The discovery of a functionally relevant signature with utility for diagnostic classification of sequence variants in EZH2, EED, and SUZ12 supports the emerging paradigm shift for implementation of DNAm signatures into diagnostics and translational research.

Stress During Pregnancy and Epigenetic Modifications to Offspring DNA: A Systematic Review of Associations and Implications for Preterm Birth

Offspring born preterm (ie, before 37 weeks of gestation) are more likely to die or experience long-standing illness than full-term offspring. Maternal genetic variants (ie, heritable, stable variations in the genetic code) and epigenetic modifications (ie, chemical modifications to the genetic code that can affect which genes are turned on or off) in response to stress have been implicated in preterm birth. Fetal genetic variants have been linked to preterm birth though the role of offspring epigenetics in preterm birth remains understudied. This systematic review synthesizes the literature examining associations among stress during pregnancy and epigenetic modifications to offspring DNA, with 25 reports identified. Ten reports examined DNA methylation (ie, addition/removal of methyl groups to/from DNA) across the epigenome. The remainder examined DNA methylation near genes of interest, primarily genes linked to hypothalamic-pituitary-adrenal axis function (NR3C1, FKBP51), growth/immune function (IGF2), and socioemotional regulation (SLC6A4, OXTR). The majority of reports noted associations among stress and offspring DNA methylation, primarily when perceived stress, anxiety, or depression served as the predictor. Findings suggest that differences in offspring epigenetic patterns may play a role in stress-associated preterm birth and serve as targets for novel interventions.

Tracing human stem cell lineage during development using DNA methylation

Stem cell maturation is a fundamental, yet poorly understood aspect of human development. We devised a DNA methylation signature deeply reminiscent of embryonic stem cells (a fetal cell origin signature, FCO) to interrogate the evolving character of multiple human tissues. The cell fraction displaying this FCO signature was highly dependent upon developmental stage (fetal versus adult), and in leukocytes, it described a dynamic transition during the first 5 yr of life. Significant individual variation in the FCO signature of leukocytes was evident at birth, in childhood, and throughout adult life. The genes characterizing the signature included transcription factors and proteins intimately involved in embryonic development. We defined and applied a DNA methylation signature common among human fetal hematopoietic progenitor cells and have shown that this signature traces the lineage of cells and informs the study of stem cell heterogeneity in humans under homeostatic conditions.

Stress and the HPA Axis: Balancing Homeostasis and Fertility

An organism’s reproductive fitness is sensitive to the environment, integrating cues of resource availability, ecological factors, and hazards within its habitat. Events that challenge the environment of an organism activate the central stress response system, which is primarily mediated by the hypothalamic–pituitary–adrenal (HPA) axis. The regulatory functions of the HPA axis govern the cardiovascular and metabolic system, immune functions, behavior, and reproduction. Activation of the HPA axis by various stressors primarily inhibits reproductive function and is able to alter fetal development, imparting a biological record of stress experienced in utero. Clinical studies and experimental data indicate that stress signaling can mediate these effects through direct actions in the brain, gonads, and embryonic tissues. This review focuses on the mechanisms by which stress activation of the HPA axis impacts fertility and fetal development.