Adverse maternal exposures, methylation of glucocorticoid-related genes and perinatal outcomes: a systematic review

Maternal perceived stress and green spaces during pregnancy are associated with adult offspring gene (NR3C1 and IGF2/H19) methylation patterns in adulthood: A pilot study

BACKGROUND

Changes in NR3C1 and IGF2/H19 methylation patterns have been associated with behavioural and psychiatric outcomes. Maternal mental state has been associated with offspring NR3C1 promotor and IGF2/H19 imprinting control region (ICR) methylation patterns. However, there is a lack of prospective studies with long-term follow-up.

METHODS

52 mother-offspring pairs were studied from 12 to 22 weeks of pregnancy and offspring was followed-up until 28-29 years-of-age. During pregnancy, mothers filled in a Life Event Scale and a Daily Hassles Scale measuring perceived stress; i.e., appraisal or subjectively experienced severity of impact of important life events and of daily hassles in several life domains during pregnancy, respectively. Green space was quantified around the residence, using high-resolution (1 m2) map data. Saliva and blood samples were obtained from the adult offspring. Absolute DNA methylation levels were determined in blood and saliva on four NR3C1 amplicons, and one IGF2/H19 ICR amplicon using a bisulfite PCR and sequencing method. Linear mixed effect models were used to test the associations between perceived stress and green spaces during pregnancy, and adult offspring methylation patterns.

RESULTS

We found associations between maternal perceived stress during pregnancy and methylation patterns on two out of the four NR3C1 amplicons, measured in blood, from offspring in adulthood, but not with IGF2/H19 methylation. For an interquartile-range (IQR) increase in maternal perceived life event or daily hassles stress scores, absolute methylation levels on several NR3C1 CpG sites were significantly changed (-1.62 % to +5.89 %, p<0.05). Maternal perceived stress scores were not associated with IGF2/H19 methylation, neither in blood nor in saliva. Maternal exposure to green spaces surrounding the residence during the pregnancy was associated with IGF2/H19 ICR methylation (-0.80 % to -1.04 %, p<0.05) in saliva, but not with NR3C1 promotor methylation.

CONCLUSION

We observed significant long-term effects of maternal perceived stress during pregnancy on the methylation patterns of the NR3C1 promotor in offspring well into adulthood. This may imply that maternal psychological distress during pregnancy may influence the regulation of the HPA-axis well into adulthood. Additionally, maternal proximity to green spaces was associated with IGF2/H19 ICR methylation patterns, which is a novel finding.

Abnormal DNA methylation within HPA-axis genes years after paediatric critical illness

BACKGROUND

Critically ill children suffer from impaired physical/neurocognitive development 2 years later. Glucocorticoid treatment alters DNA methylation within the hypothalamus-pituitary-adrenal (HPA) axis which may impair normal brain development, cognition and behaviour. We tested the hypothesis that paediatric-intensive-care-unit (PICU) patients, sex- and age-dependently, show long-term abnormal DNA methylation within the HPA-axis layers, possibly aggravated by glucocorticoid treatment in the PICU, which may contribute to the long-term developmental impairments.

RESULTS

In a pre-planned secondary analysis of the multicentre PEPaNIC-RCT and its 2-year follow-up, we identified differentially methylated positions and differentially methylated regions within HPA-axis genes in buccal mucosa DNA from 818 former PICU patients 2 years after PICU admission (n = 608 no glucocorticoid treatment; n = 210 glucocorticoid treatment) versus 392 healthy children and assessed interaction with sex and age, role of glucocorticoid treatment in the PICU and associations with long-term developmental impairments. Adjusting for technical variation and baseline risk factors and correcting for multiple testing (false discovery rate < 0.05), former PICU patients showed abnormal DNA methylation of 26 CpG sites (within CRHR1, POMC, MC2R, NR3C1, FKBP5, HSD11B1, SRD5A1, AKR1D1, DUSP1, TSC22D3 and TNF) and three DNA regions (within AVP, TSC22D3 and TNF) that were mostly hypomethylated. These abnormalities were sex-independent and only partially age-dependent. Abnormal methylation of three CpG sites within FKBP5 and one CpG site within SRD5A1 and AKR1D1 was partly attributable to glucocorticoid treatment during PICU stay. Finally, abnormal methylation within FKBP5 and AKR1D1 was most robustly associated with long-term impaired development.

CONCLUSIONS

Two years after critical illness in children, abnormal methylation within HPA-axis genes was present, predominantly within FKBP5 and AKR1D1, partly attributable to glucocorticoid treatment in the PICU, and explaining part of the long-term developmental impairments. These data call for caution regarding liberal glucocorticoid use in the PICU.

The impact of DNA methylation as a factor of Adverse Pregnancy and Birth Outcomes (APBOs): a systematic review protocol

BACKGROUND

Deoxyribonucleic acid (DNA) methylation is one of the epigenetic modifications that has gained a lot of interest as a factor influencing fetal programming and as a biomarker for adverse pregnancy and birth outcomes (APBOs). Epidemiological studies have demonstrated that DNA methylation can result in adverse pregnancy and birth outcomes (APBOs) including miscarriage, intrauterine growth restriction (IUGR), low birth weight (LBW), sepsis, and preterm birth (PTB), which may later result in diseases in adulthood. However, the mechanism by which DNA methylation influences these APBOs remains unclear. The systematic review will assess the association between global and gene-specific DNA methylation with adverse pregnancy outcomes.

METHOD

The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020 checklist will be followed when conducting this systematic review. To develop the search strategy the PI(E)COS (population, intervention/exposure, comparator/control, outcome, and study designs) framework will be followed. Thus far, the research team has retrieved 4721 from Cochrane Library, PubMed, Web of Sciences, and MEDLINE. Out of these, 584 studies have been screened for eligibility, and approximately 124 studies meet the inclusion criteria. Pending the search results identified from the grey literature. For identification of unpublished studies in journals indexed in electronic databases, Google Scholar will be used. I.M and A.S will separately extract data from the articles and screen them, if there are any disagreements between I.M and A.S, then the L.M will resolve them. The methodological quality and bias risk of the included studies will be evaluated using the Critical Appraisal Skill Programme CASP) checklist. [Formula: see text] and [Formula: see text] alpha = 0.10 statistic will be used for assessing statistical heterogeneity between studies. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach will be used to assess and grade the overall quality of extracted data.

ETHICS AND DISSEMINATION

Ethical approval is not required. The systematic review will assess available literature on possible associations between DNA methylation with adverse pregnancy and birth outcomes (APBOs) including LBW, IUGR, miscarriage, sepsis, and PTB. The findings could help guide future research assessing DNA methylation and other APBOs.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRCRD42022370647.

Evaluation of DNA methylation in BDNF, SLC6A4, NR3C1 and FKBP5 before and after treatment with selective serotonin-reuptake inhibitor in major depressive disorder

Aim: To identify the DNA methylation status of related genes in major depressive disorder following selective serotonin-reuptake inhibitor treatment. Materials & methods: 45 patients with major depressive disorder and 45 healthy volunteers were considered experimental and control groups, respectively. High-resolution melting real-time PCR was implemented to evaluate DNA methylation. Results: After 100 days of selective serotonin-reuptake inhibitor treatment, methylation of promoter CpG sites of BDNF, NR3C1, FKBP5 and SLC6A4 was significantly reduced. Compared with before treatment, patients' Hamilton Depression Rating Scale scores were significantly reduced after selective serotonin-reuptake inhibitor treatment (p ≤ 0.0001). Conclusion: Based on the proven effect of antidepressants on DNA methylation and gene expression, these medications can improve the treatment process and reduce depression scores after treatment.

The association between peritraumatic distress, perceived stress, depression in pregnancy, and NR3C1 DNA methylation among Chinese pregnant women who experienced COVID-19 lockdown

Prenatal stress can affect pregnant women in an epigenetic way during the critical period of conception of their offspring. The study aims to investigate the relationship between peritraumatic distress, prenatal perceived stress, depression, and glucocorticoid receptor (NR3C1) DNA methylation among pregnant women who experienced COVID-19 lockdown in China. Study data were collected from 30 pregnant women in Wuhan and Huanggang, China. The Peritraumatic Distress Inventory was used to measure peritraumatic distress, the Edinburgh Postnatal Depression Scale was used to measure depressive symptoms, and the Perceived Stress Scale was used to measure perceived stress. DNA methylation in the exon 1F promoter region of NR3C1 gene from the venous blood mononuclear cell genome was characterized by bisulfite sequencing. Correlation and linear regression were used for data analysis. The mean level of peritraumatic distress, perceived stress, and depression was 6.30 (SD = 5.09), 6.50 (SD = 5.41), and 6.60 (SD = 4.85), respectively, with 23.33% of pregnant women being depressed. The mean NR3C1 methylation was 0.65 (SD = 0.22). Prenatal depression was positively correlated with the degree of methylation in venous blood from the mother (r = 0.59, p = 0.001), and depression predicted methylation of NR3C1 gene at the CpG 8 site (β = 0.05, p = 0.03). No association was found between peritraumatic distress as well as perceived stress and methylation of NR3C1. NR3C1 gene was susceptible to epigenetic modification of DNA methylation in the context of prenatal stress, and maternal depression was associated with increased NR3C1 methylation among women who experienced COVID-19 lockdown.

Antenatal Steroids and Cord Blood T-cell Glucocorticoid Receptor DNA Methylation and Exon 1 Splicing

Antenatal administration of glucocorticoids such as betamethasone (BMZ) during the late preterm period improves neonatal respiratory outcomes. However, glucocorticoids may elicit programming effects on immune function and gene regulation. Here, we test the hypothesis that exposure to antenatal BMZ alters cord blood immune cell composition in association with altered DNA methylation and alternatively expressed Exon 1 transcripts of the glucocorticoid receptor (GR) gene in cord blood CD4⁺ T-cells. Cord blood was collected from 51 subjects in the Antenatal Late Preterm Steroids Trial: 27 BMZ, 24 placebo. Proportions of leukocytes were compared between BMZ and placebo. In CD4+ T-cells, methylation at CpG sites in the GR promoter regions and expression of GR mRNA exon 1 variants were compared between BMZ and placebo. BMZ was associated with an increase in granulocytes (51.6% vs. 44.7% p = 0.03) and a decrease in lymphocytes (36.8% vs. 43.0% p = 0.04) as a percent of the leukocyte population vs. placebo. Neither GR methylation nor exon 1 transcript levels differed between groups. BMZ is associated with altered cord blood leukocyte proportions, although no associated alterations in GR methylation were observed.

Pregnancy and Infant Development (PRIDE)-a preliminary observational study of maternal adversity and infant development

Background

Children from socioeconomically disadvantaged families have a markedly elevated risk for impaired cognitive and social-emotional development. Children in poverty experience have a high risk for developmental delays. Poverty engenders disproportionate exposure to psychological adversity which may contribute to impaired offspring development; however the effect may be mitigated by social support and other aspects of resilience. Our objective was to determine the association between maternal stress, adversity and social support and early infant neurobehavior and child behavior at two and three years.

Methods

We conducted a longitudinal mother-infant cohort study nested within a regional home visiting program in Cincinnati, Ohio. Four home study visits were completed to collect measures of maternal stress, adversity and social support and infant and child behavior. A measure of infant neurobehavior (‘high-arousal’ infant) was derived from the NICU Network Neurobehavioral Scale (NNNS) at 1 month and externalizing and internalizing symptoms were measured by the Child Behavior Checklist (CBCL) at 24 and 36 months. Linear and logistic regression identified associations between maternal risk/protective factors and infant and child behavioral measures. We used stratification and multiplicative interaction terms to examine potential interactions.

Results

We enrolled n = 55 pregnant mothers and follow 53 mother–offspring dyads at 1 month, 40 dyads at 24 months and 27 dyads at 36 months. Maternal adversity and protective factors were not associated with neurobehavior at one month. However, maternal depression and measures of distress in pregnancy were significantly associated with internalizing and externalizing symptoms at 24 and 36 months.

Conclusions

This pilot study established the feasibility of conducting longitudinal research within a community intervention program. In addition, although there were no statistically significant associations between maternal psychosocial factors in pregnancy and infant neurobehavior, there were several associations at 24 months, primarily internalizing symptoms, which persisted through 36 months. Future work will replicate findings within a larger study as well as explore mediators and modifiers of these associations.

Cortisol Dose-Dependently Impairs Migration and Tube-like Formation in a Trophoblast Cell Line and Modulates Inflammatory and Angiogenic Genes

Several stimuli can change maternal hormone levels during pregnancy. These changes may affect trophoblastic cells and modulate the development of the embryo and the placental tissue itself. Changes in cortisol levels are associated with impaired trophoblast implantation and function, in addition to other pregnancy complications. This study aims to analyze the effects of low and high doses of cortisol on an extravillous trophoblast cell line, and the effects of various exposures to this hormone. SGHPL-4 cells were treated with cortisol at five doses (0-1000 nM) and two exposures (continuous: 24 h/day; and intermittent: 2 h/day). In intermittent treatment, cortisol acted mainly as an anti-inflammatory hormone, repressing gene expression of kinin B1 receptors, interleukin-6, and interleukin-1β. Continuous treatment modulated inflammatory and angiogenic pathways, significantly repressing angiogenic factors and their receptors. Cortisol affected cell migration and tube-like structures formation. In conclusion, both continuous and intermittent exposure to cortisol repressed the expression of inflammatory genes, while only continuous exposure repressed the expression of angiogenic genes, suggesting that a sustained increase in the levels of this hormone is more harmful than a high short-term increase. Cortisol also impaired tube-like structures formation, and kinin receptors may be involved in this response.

The contribution of ethnography to epigenomics research: toward a new bio-ethnography for addressing health disparities

This article describes ethnography as a research method and outlines how it excels in capturing the salient experiences of individuals among diverse communities in their own words. We argue that the integration of ethnographic findings into epigenomics will significantly improve disparities-focused study designs within environmental epigenomics by identifying and contextualizing the most salient dimensions of the 'environment' that are affecting local communities. Reciprocally, epigenetic findings can enhance anthropological understanding of human biological variation and embodiment. We introduce the term bio-ethnography to refer to research designs that integrate both of these methodologies into a single research project. Emphasis is given in this article, through the use of case studies, to socially disadvantaged communities that are often underrepresented in scientific literature. The paper concludes with preliminary recommendations for how ethnographic methods can be integrated into epigenomics research designs in order to elucidate the manner in which disadvantage translates into disparities in the burden of illness.

Revisiting preeclampsia: a metabolic disorder of the placenta

Preeclampsia (PE) is a leading cause of maternal and neonatal mortality and morbidity worldwide, impacting the long-term health of both mother and offspring. PE has long been characterized by deficient trophoblast invasion into the uterus and consequent placental hypoperfusion, yet the upstream causative factors and effective interventional targets for PE remain unknown. Alterations in the metabolism of preeclamptic placentas are thought to result from placental ischemia, while disturbances of the metabolism and of metabolites in PE pathogenesis are largely ignored. In fact, as one of the largest fetal organs at birth, the placenta consumes a considerable amount of glucose and fatty acid. Increasing evidence suggests glucose and fatty acid exist as energy substrates and regulate placental development through bioactive derivates. Moreover, recent findings have revealed that the placental metabolism adapts readily to environmental changes, altering its response to nutrients and endocrine signals; this adaptability optimizes pregnancy outcomes by diversifying available carbon sources for energy production, hormone synthesis, angiogenesis, immune activation, and tolerance, and fetoplacental growth. These observations raise the possibility that carbohydrate and lipid metabolism abnormalities play a role in both the etiology and clinical progression of PE, sparking a renewed interest in the interrelationship between PE and metabolic dysregulation. This review will focus on key metabolic substrates and regulatory molecules in the placenta and aim to provide novel insights with respect to the metabolism's role in modulating placental development and functions. Further investigations from this perspective are poised to decipher the etiology of PE and suggest potential therapies.

Resilience: Safety in the Aftermath of Traumatic Stressor Experiences

The relationship between adverse experiences and the emergence of pathology has often focused on characteristics of the stressor or of the individual (stressor appraisals, coping strategies). These features are thought to influence multiple biological processes that favor the development of mental and physical illnesses. Less often has attention focused on the aftermath of traumatic experiences, and the importance of safety and reassurance that is necessary for longer-term well-being. In some cases (e.g., post-traumatic stress disorder) this may be reflected by a failure of fear extinction, whereas in other instances (e.g., historical trauma), the uncertainty about the future might foster continued anxiety. In essence, the question becomes one of how individuals attain feelings of safety when it is fully understood that the world is not necessarily a safe place, uncertainties abound, and feelings of agency are often illusory. We consider how individuals acquire resilience in the aftermath of traumatic and chronic stressors. In this respect, we review characteristics of stressors that may trigger particular biological and behavioral coping responses, as well as factors that undermine their efficacy. To this end, we explore stressor dynamics and social processes that foster resilience in response to specific traumatic, chronic, and uncontrollable stressor contexts (intimate partner abuse; refugee migration; collective historical trauma). We point to resilience factors that may comprise neurobiological changes, such as those related to various stressor-provoked hormones, neurotrophins, inflammatory immune, microbial, and epigenetic processes. These behavioral and biological stress responses may influence, and be influenced by, feelings of safety that come about through relationships with others, spiritual and place-based connections.

Epigenetic Biomarkers for Environmental Exposures and Personalized Breast Cancer Prevention

Environmental and lifestyle factors are believed to account for >80% of breast cancers; however, it is not well understood how and when these factors affect risk and which exposed individuals will actually develop the disease. While alcohol consumption, obesity, and hormone therapy are some known risk factors for breast cancer, other exposures associated with breast cancer risk have not yet been identified or well characterized. In this paper, it is proposed that the identification of blood epigenetic markers for personal, in utero, and ancestral environmental exposures can help researchers better understand known and potential relationships between exposures and breast cancer risk and may enable personalized prevention strategies.

Perinatal Outcomes of Small for Gestational Age Neonates Born With an Isolated Single Umbilical Artery

Objective: To investigate pregnancy outcomes of small for gestational age (SGA) neonates born with isolated single umbilical artery (iSUA) compared to SGA neonates without iSUA. Study Design: This was a population-based retrospective cohort analysis. The study group was defined as a singleton SGA neonate born with iSUA, while an SGA neonate without iSUA comprised the comparison group. We evaluated adverse perinatal outcomes in all SGA neonates born at the Soroka University Medical Center between the years 1998-2013. Multiple gestations, fetuses with known congenital malformations or chromosomal abnormalities and patients with lack of prenatal care were excluded from the study. Multivariate logistic regression models were constructed to identify independent factors associated with adverse perinatal outcomes. Results: Of 12,915 SGA deliveries, 1.2% (162) were complicated with iSUA. Women in the study group were older with a significantly lower gestational age at delivery compared with the comparison group. Rates of women who conceived after infertility treatments were higher in the study group. Additionally, patients in the study group had significantly higher rates of preterm deliveries, placental abruption, cord prolapse, non-reassuring fetal heart rates and cesarean delivery were noted in the study group. These neonates had a significantly lower birth weight (1988.0 ± 697 vs. 2388.3 ± 481 p < 0.001) and higher rates of low APGAR scores at the first and fifth minutes after birth compared with controls. Perinatal mortality was also found to be significantly higher among SGA neonates complicated with iSUA. Preterm delivery as well as perinatal mortality were found independently associated with iSUA among SGA neonates (aOR 4.01, 95% CI 2.88-5.59, aOR 2.24, 95% CI 1.25-4.01, respectively). Conclusion: SGA pregnancies complicated with iSUA are at higher risk for adverse pregnancy and perinatal outcomes as compared to SGA pregnancies without iSUA.

Environmentally Induced Epigenetic Plasticity in Development: Epigenetic Toxicity and Epigenetic Adaptation

PURPOSE OF REVIEW

Epigenetic processes represent important mechanisms underlying developmental plasticity in response to environmental exposures. The current review discusses three classes of environmentally-induced epigenetic changes reflecting two aspects of that plasticity, toxicity effects as well as adaptation in the process of development.

RECENT FINDINGS

Due to innate resilience, epigenetic changes caused by environmental exposures may not always lead impairments but may allow the organisms to achieve positive developmental outcomes through appropriate adaptation and a buffering response. Thus, some epigenetic adaptive responses to an immediate stimulus or exposure early in life would be expected to have a survival advantage but these same responses may also result in adverse developmental outcomes as they persists into later life stage. Although accumulating literature has identified environmentally induced epigenetic changes and linked them to health outcomes, we currently face challenges in the interpretation of the functional impact of their epigenetic plasticity.

SUMMARY

Current environmental epigenetic research suggest that epigenetic processes may serve as a mechanism for resilience, and that they can be considered in terms of their impact on toxicity as a negative outcome, but also on adaptation for improved survival or health. This review encourages epigenetic environmental studies to move deeper inside into the functional meaning of epigenetic plasticity in the development.