Foetoplacental epigenetic changes associated with maternal metabolic dysfunction

Fetoplacental endothelial dysfunction in gestational diabetes mellitus and maternal obesity: A potential threat for programming cardiovascular disease

Gestational diabetes mellitus (GDM) and maternal obesity (MO) increase the risk of adverse fetal outcomes, and the incidence of cardiovascular disease later in life. Extensive research has been conducted to elucidate the underlying mechanisms by which GDM and MO program the offspring to disease. This review focuses on the role of fetoplacental endothelial dysfunction in programming the offspring for cardiovascular disease in GDM and MO pregnancies. We discuss how pre-existing maternal health conditions can lead to vascular dysfunction in the fetoplacental unit and the fetus. We also examine the role of fetoplacental endothelial dysfunction in impairing fetal cardiovascular system development and the involvement of nitric oxide and hydrogen sulfide in mediating fetoplacental vascular dysfunction. Furthermore, we suggest that the L-Arginine-Nitric Oxide and the Adenosine-L-Arginine-Nitric Oxide (ALANO) signaling pathways are pertinent targets for research. Despite significant progress in this area, there are still knowledge gaps that need to be addressed in future research.

Consequences of the exposome to gestational diabetes mellitus

The exposome is the cumulative measure of environmental influences and associated biological responses throughout the lifespan, including those from the environment, diet, behaviour, and endogenous processes. The exposome concept and the 2030 Agenda for the Sustainable Development Goals (SDGs) from the United Nations are the basis for understanding the aetiology and consequences of non-communicable diseases, including gestational diabetes mellitus (GDM). Pregnancy may be developed in an environment with adverse factors part of the immediate internal medium for fetus development and the external medium to which the pregnant woman is exposed. The placenta is the interface between maternal and fetal compartments and acts as a protective barrier or easing agent to transfer exposome from mother to fetus. Under and over-nutrition in utero, exposure to adverse environmental pollutants such as heavy metals, endocrine-disrupting chemicals, pesticides, drugs, pharmaceuticals, lifestyle, air pollutants, and tobacco smoke plays a determinant role in the development of GDM. This phenomenon is worsened by metabolic stress postnatally, such as obesity which increases the risk of GDM and other diseases. Clinical risk factors for GDM development include its aetiology. It is proposed that knowledge-based interventions to change the potential interdependent ecto-exposome and endo-exposome could avoid the occurrence and consequences of GDM.

Epigenetic Profiling in the Saliva of Obese Pregnant Women

Maternal obesity is associated with inflammation and oxidative stress, strongly impacting the intrauterine environment with detrimental consequences for both mother and offspring. The saliva is a non-invasive biofluid reflecting both local and systemic health status. This observational study aimed to profile the epigenetic signature in the saliva of Obese (OB) and Normal-Weight (NW) pregnant women. Sixteen NW and sixteen OB Caucasian women with singleton spontaneous pregnancies were enrolled. microRNAs were quantified by the OpenArray Platform. The promoter region methylation of Suppressor of Cytokine Signaling 3 (SOCS3) and Transforming Growth Factor Beta 1 (TGF-Beta1) was assessed by pyrosequencing. There were 754 microRNAs evaluated: 20 microRNAs resulted in being differentially expressed between OB and NW. microRNA pathway enrichment analysis showed a significant association with the TGF-Beta signaling pathway (miTALOS) and with fatty acids biosynthesis/metabolism, lysine degradation, and ECM–receptor interaction pathways (DIANA–miRPath). Both SOCS3 and TGF-Beta1 were significantly down-methylated in OB vs. NW. These results help to clarify impaired mechanisms involved in obesity and pave the way for the understanding of specific damaged pathways. The characterization of the epigenetic profile in saliva of pregnant women can represent a promising tool for the identification of obesity-related altered mechanisms and of possible biomarkers for early diagnosis and treatment of pregnancy-adverse conditions.

Sperm Histone H3 Lysine 4 tri-methylation serves as a metabolic sensor of paternal obesity and is associated with the inheritance of metabolic dysfunction

Objective

Parental environmental exposures can strongly influence descendant risks for adult disease. How paternal obesity changes the sperm chromatin leading to the acquisition of metabolic disease in offspring remains controversial and ill-defined. The objective of this study was to assess (1) whether obesity induced by a high-fat diet alters sperm histone methylation; (2) whether paternal obesity can induce metabolic disturbances across generations; (3) whether there could be cumulative damage to the sperm epigenome leading to enhanced metabolic dysfunction in descendants; and (4) whether obesity-sensitive regions associate with embryonic epigenetic and transcriptomic profiles. Using a genetic mouse model of epigenetic inheritance, we investigated the role of histone H3 lysine 4 methylation (H3K4me3) in the paternal transmission of metabolic dysfunction. This transgenic mouse overexpresses the histone demethylase enzyme KDM1A in the developing germline and has an altered sperm epigenome at the level of histone H3K4 methylation. We hypothesized that challenging transgenic sires with a high-fat diet would further erode the sperm epigenome and lead to enhanced metabolic disturbances in the next generations.

Methods

To assess whether paternal obesity can have inter- or transgenerational impacts, and if so to identify potential mechanisms of this non-genetic inheritance, we used wild-type C57BL/6NCrl and transgenic males with a pre-existing altered sperm epigenome. To induce obesity, sires were fed either a control or high-fat diet (10% or 60% kcal fat, respectively) for 10–12 weeks, then bred to wild-type C57BL/6NCrl females fed a regular diet. F₁ and F₂ descendants were characterized for metabolic phenotypes by examining the effects of paternal obesity by sex, on body weight, fat mass distribution, the liver transcriptome, intraperitoneal glucose, and insulin tolerance tests. To determine whether obesity altered the F₀ sperm chromatin, native chromatin immunoprecipitation-sequencing targeting H3K4me3 was performed. To gain insight into mechanisms of paternal transmission, we compared our sperm H3K4me3 profiles with embryonic and placental chromatin states, histone modification, and gene expression profiles.

Results

Obesity-induced alterations in H3K4me3 occurred in genes implicated in metabolic, inflammatory, and developmental processes. These processes were associated with offspring metabolic dysfunction and corresponded to genes enriched for H3K4me3 in embryos and overlapped embryonic and placenta gene expression profiles. Transgenerational susceptibility to metabolic disease was only observed when obese F₀ had a pre-existing modified sperm epigenome. This coincided with increased H3K4me3 alterations in sperm and more severe phenotypes affecting their offspring.

Conclusions

Our data suggest sperm H3K4me3 might serve as a metabolic sensor that connects paternal diet with offspring phenotypes via the placenta. This non-DNA-based knowledge of inheritance has the potential to improve our understanding of how environment shapes heritability and may lead to novel routes for the prevention of disease. This study highlights the need to further study the connection between the sperm epigenome, placental development, and children's health.

Summary sentence

Paternal obesity impacts sperm H3K4me3 and is associated with placenta, embryonic and metabolic outcomes in descendants.

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Sperm H3K4me3 serves as a metabolic sensor of HFD-induced obesity.

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Obesity-altered sperm H3K4me3 corresponds to embryonic transcription and chromatin profiles.

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HFD- and KDM1A-induced cumulative sperm epimutations enhanced F₁ metabolic dysfunction.

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Sperm epimutations may influence placenta function inducing F₁ metabolic phenotypes.

Assessment of the Cardiovascular Risk Profile of Infants Exposed to Pre-eclampsia in-utero: A Prospective Case-Control Study in South African Children of African Ancestry

Background: It has been reported that maternal gestational environment may be programmed to have a significant impact on foetal and offspring health later in life. Studies have shown that children born to pre-eclamptic mothers are prone to obesity, hypertension, and diabetes in their adult life. However, such findings are yet to be established in an African population. This protocol is for a study aiming to investigate the relationship between pre-eclampsia (PE) and cardiovascular risk in children born to pre-eclamptic mothers in a South African population of African descents.

Methods: A prospective case-control design will be employed to recruit pre-eclamptic and normotensive pregnant women and their offspring after birth. Pregnant women will be assessed for cardiovascular risk factors including PE, obesity, haemodynamics, lipids, glycaemic indices, oxidative stress, and vascular function at 30 weeks of gestation. The cardiovascular risk profile of their offspring will be assessed at birth and 6 weeks later. The difference in cardiovascular risk profile between children born to the pre-eclamptic and normotensive mothers will be compared and the correlation between maternal and offspring cardiovascular risks will be investigated.

Discussion: This will be the first prospective study to assess the in-utero effect of cardiovascular risk in offspring born to pre-eclamptic women of African ancestry. It is expected that findings from this study will provide information on the cardiovascular effect of in-utero exposure to PE in a population of African ancestry. This knowledge will advise policy on the management of women with PE with a view of protecting cardiovascular health in offspring.

Fetoplacental vasculature as a model to study human cardiovascular endocrine disruption

Increasing evidence has associated the exposure of endocrine-disrupting chemicals (EDCs) with the cardiovascular (CV) system. This exposure is particularly problematic in a sensitive window of development, pregnancy. Pregnancy exposome can affect the overall health of the pregnancy by dramatic changes in vascular physiology and endocrine activity, increasing maternal susceptibility. Moreover, fetoplacental vascular function is generally altered, increasing the risk of developing pregnancy complications (including cardiovascular diseases, CVD) and predisposing the foetus to adverse health risks later in life. Thus, our review summarizes the existing literature on exposures to EDCs during pregnancy and adverse maternal health outcomes, focusing on the human placenta, vein, and umbilical artery associated with pregnancy complications. The purpose of this review is to highlight the role of fetoplacental vasculature as a model for the study of human cardiovascular endocrine disruption. Therefore, we emphasize that the placenta, together with the umbilical arteries and veins, allows a better characterization of the pregnant woman's exposome. Consequently, it contributes to the protection of the mother and foetus against CV disorders in life.

Placental Gene Co-expression Network for Maternal Plasma Lipids Revealed Enrichment of Inflammatory Response Pathways

Maternal dyslipidemia during pregnancy has been associated with suboptimal fetal growth and increased cardiometabolic diseasse risk in offspring. Altered placental function driven by placental gene expression is a hypothesized mechanism underlying these associations. We tested the relationship between maternal plasma lipid concentrations and placental gene expression. Among 64 pregnant women from the NICHD Fetal Growth Studies–Singleton cohort with maternal first trimester plasma lipids we extracted RNA-Seq on placental samples obtained at birth. Placental gene co-expression networks were validated by regulatory network analysis that integrated transcription factors and gene expression, and genome-wide transcriptome analysis. Network analysis detected 24 gene co-expression modules in placenta, of which one module was correlated with total cholesterol (r = 0.27, P-value = 0.03) and LDL-C (r = 0.31, P-value = 0.01). Genes in the module (n = 39 genes) were enriched in inflammatory response pathways. Out of the 39 genes in the module, three known lipid-related genes (MPO, PGLYRP1 and LTF) and MAGEC2 were validated by the regulatory network analysis, and one known lipid-related gene (ALX4) and two germ-cell development-related genes (MAGEC2 and LUZP4) were validated by genome-wide transcriptome analysis. Placental gene expression signatures associated with unfavorable maternal lipid concentrations may be potential pathways underlying later life offspring cardiometabolic traits.

Clinical Trial Registration:ClinicalTrials.gov, identifier NCT00912132.

DNA damage analysis in newborns and their mothers related to pregnancy and delivery characteristics

INTRODUCTION

Increased DNA damage is associated with early events in carcinogenesis. The foetus may be more susceptible to effects of environment by transplacental exposure. We aimed to evaluate DNA damage in cells from umbilical cord (arteries and vein) and maternal blood from pregnant women.

METHODS

Fifty eight pregnant women and their offspring were included in this study. They were submitted to an interview to obtain information about personal history, clinical history, and lifestyle habits. Other Information was obtained from medical records. The samples were prepared for Single Cell Gel/Comet assay and Cytokinesis-block Micronucleus Cytome (CBMN-Cyt) assay.

RESULTS

Correlation between DNA damage frequency by Comet assay from newborns and their mothers was statistically significant and was significantly associated with nulliparity and more than 1 h of second stage of labour (umbilical vein and maternal blood). A positive MNi relationship was noticed for age (mother's blood) and inappropriate birth weight for gestational age (maternal blood). When multivariate statistical analyses were applied to measure the degree of association between variables that influenced DNA damage markers in the first evaluation, inadequate birth weight and pregnant weight gain were associated with MNi frequency in maternal and newborns blood, respectively.

DISCUSSION

Significant associations between DNA damage in newborns and pregnant women, and birth and pregnancy events suggest molecular evidence of transplacental genotoxic effects. However, a potentially increased risk of degenerative diseases, such as cancers, in this population should be carefully investigated by further prospective cohort studies.

Maternal Melatonin Deficiency Leads to Endocrine Pathologies in Children in Early Ontogenesis

The review summarizes the results of experimental and clinical studies aimed at elucidating the causes and pathophysiological mechanisms of the development of endocrine pathology in children. The modern data on the role of epigenetic influences in the early ontogenesis of unfavorable factors that violate the patterns of the formation of regulatory mechanisms during periods of critical development of fetal organs and systems and contribute to the delayed development of pathological conditions are considered. The mechanisms of the participation of melatonin in the regulation of metabolic processes and the key role of maternal melatonin in the formation of the circadian system of regulation in the fetus and in the protection of the genetic program of its morphofunctional development during pregnancy complications are presented. Melatonin, by controlling DNA methylation and histone modification, prevents changes in gene expression that are directly related to the programming of endocrine pathology in offspring. Deficiency and absence of the circadian rhythm of maternal melatonin underlies violations of the genetic program for the development of hormonal and metabolic regulatory mechanisms of the functional systems of the child, which determines the programming and implementation of endocrine pathology in early ontogenesis, contributing to its development in later life. The significance of this factor in the pathophysiological mechanisms of endocrine disorders determines a new approach to risk assessment and timely prevention of offspring diseases even at the stage of family planning.

Developmental origins of metabolic diseases

Almost 2 billion adults in the world are overweight, and more than half of them are classified as obese, while nearly one-third of children globally experience poor growth and development. Given the vast amount of knowledge that has been gleaned from decades of research on growth and development, a number of questions remain as to why the world is now in the midst of a global epidemic of obesity accompanied by the "double burden of malnutrition," where overweight coexists with underweight and micronutrient deficiencies. This challenge to the human condition can be attributed to nutritional and environmental exposures during pregnancy that may program a fetus to have a higher risk of chronic diseases in adulthood. To explore this concept, frequently called the developmental origins of health and disease (DOHaD), this review considers a host of factors and physiological mechanisms that drive a fetus or child toward a higher risk of obesity, fatty liver disease, hypertension, and/or type 2 diabetes (T2D). To that end, this review explores the epidemiology of DOHaD with discussions focused on adaptations to human energetics, placental development, dysmetabolism, and key environmental exposures that act to promote chronic diseases in adulthood. These areas are complementary and additive in understanding how providing the best conditions for optimal growth can create the best possible conditions for lifelong health. Moreover, understanding both physiological as well as epigenetic and molecular mechanisms for DOHaD is vital to most fully address the global issues of obesity and other chronic diseases.

Oral L-glutamine rescues fructose-induced poor fetal outcome by preventing placental triglyceride and uric acid accumulation in Wistar rats

BACKGROUND

Metabolic adaptation of pregnant mothers is crucial for placental development and fetal growth/survival. However, evidence exists that indiscriminate consumption of fructose-enriched drink (FED) during pregnancy disrupts maternal-fetal metabolic tolerance with attendant adverse fetal outcomes. Glutamine supplementation (GLN) has been shown to exert a modulatory effect in metabolic disorders. Nevertheless, the effects of GLN on FED-induced poor fetal outcome, and in particular the impacts on placental uric acid/lipid accumulation are unknown. The present study was conducted to test the hypothesis that oral GLN improves fetal outcome by attenuating placental lipid accumulation and uric acid synthesis in pregnant rats exposed to FED.

MATERIALS AND METHODS

Pregnant Wistar rats (160-180 g) were randomly allotted to control, GLN, FED and FED + GLN groups (6 rats/group). The groups received vehicle by oral gavage, glutamine (1 g/kg) by oral gavage, fructose (10%; w/v) and fructose + glutamine, respectively, through gestation.

RESULTS

Data showed that FED during pregnancy caused placental inefficiency, reduced fetal growth, and caused insulin resistance with correspondent increase in fasting blood glucose and plasma insulin. FED also resulted in an increased placental triglyceride, total cholesterol and de novo uric acid synthesis by activating adenosine deaminase and xanthine oxidase activities. Moreover, FED during pregnancy led to increased lipid peroxidation, lactate production with correspondent decreased adenosine and glucose-6-phosphate dehydrogenase-dependent antioxidant defense. These alterations were abrogated by GLN supplementation.

CONCLUSION

These findings implicate that high FED intake during pregnancy causes poor fetal outcome via defective placental uric acid/triglyceride-dependent mechanism. The findings also suggest that oral GLN improves fetal outcome by ameliorating placental defects through suppression of uric acid/triglyceride accumulation.

Epigenetic alternations of microRNAs and DNA methylation contribute to gestational diabetes mellitus

This study aimed to identify epigenetic alternations of microRNAs and DNA methylation for gestational diabetes mellitus (GDM) diagnosis and treatment using in silico approach. Data of mRNA and miRNA expression microarray (GSE103552 and GSE104297) and DNA methylation data set (GSE106099) were obtained from the GEO database. Differentially expressed genes (DEGs), differentially expressed miRNAs (DEMs) and differentially methylated genes (DMGs) were obtained by limma package. Functional and enrichment analyses were performed with the DAVID database. The protein‐protein interaction (PPI) network was constructed by STRING and visualized in Cytoscape. Simultaneously, a connectivity map (CMap) analysis was performed to screen potential therapeutic agents for GDM. In GDM, 184 low miRNA‐targeting up‐regulated genes and 234 high miRNA‐targeting down‐regulated genes as well as 364 hypomethylation–high‐expressed genes and 541 hypermethylation–low‐expressed genes were obtained. They were mainly enriched in terms of axon guidance, purine metabolism, focal adhesion and proteasome, respectively. In addition, 115 genes (67 up‐regulated and 48 down‐regulated) were regulated by both aberrant alternations of miRNAs and DNA methylation. Ten chemicals were identified as putative therapeutic agents for GDM and four hub genes (IGF1R, ATG7, DICER1 and RANBP2) were found in PPI and may be associated with GDM. Overall, this study identified a series of differentially expressed genes that are associated with epigenetic alternations of miRNA and DNA methylation in GDM. Ten chemicals and four hub genes may be further explored as potential drugs and targets for GDM diagnosis and treatment, respectively.

Endothelial Extracellular Vesicles Produced by Senescent Cells: Pathophysiological Role in the Cardiovascular Disease Associated with all Types of Diabetes Mellitus

Endothelial senescence-associated with aging or induced prematurely in pathological situations, such as diabetes, is a first step in the development of Cardiovascular Disease (CVDs) and particularly inflammatory cardiovascular diseases. The main mechanism that links endothelial senescence and the progression of CVDs is the production of altered Extracellular Vesicles (EVs) by senescent endothelial cells among them, Microvesicles (MVs). MVs are recognized as intercellular signaling elements that play a key role in regulating tissue homeostasis. However, MVs produced by damage cell conveyed epigenetic signals, mainly involving microRNAs, which induce many of the injured responses in other vascular cells leading to the development of CVDs. Many studies strongly support that the quantification and characterization of the MVs released by senescent endothelial cells may be useful diagnostic tools in patients with CVDs, as well as a future therapeutic target for these diseases. In this review, we summarize the current knowledge linking senescence-associated MVs to the development of CVDs and discuss the roles of these MVs, in particular, in diabetic-associated increases the risk of CVDs.

Schizophrenia and motherhood

The primary aim of this study was to analyze the impact of schizophrenic disorders on pregnancy outcomes. The secondary aim was to briefly analyze the potential role of antipsychotic treatment on influencing pregnancy outcomes in expectant mothers with schizophrenia. We searched the MEDLINE, PsycINFO, and Science.gov databases for articles published in English from January 1980 to January 2019. We used the following search terms: 'schizophrenia', 'motherhood', 'pregnancy/foetal/neonatal outcomes', and 'birth defects'. The reference lists of retrieved articles were also consulted to find additional pertinent studies missed in the electronic search and/or those published before 1980. Data were extracted from articles that provided primary data on the impact of maternal schizophrenia spectrum disorders on obstetrical and perinatal outcomes. After excluding duplicates, 35 articles were identified. Systematic reviews were searched on the same databases to briefly assess the effects of antipsychotics on pregnancy outcomes. The reviewed studies showed several limitations. They were published during a time range from the early 1970s to 2019. During this period, there were significant changes in the diagnostic criteria for schizophrenia. Moreover, such studies showed no homogeneity in the investigation of potential confounders. Most importantly, no research has differentiated the effects of maternal illness on pregnancy, fetal, and neonatal outcomes from those associated with antipsychotic treatments. Thus, it is not surprising that such studies show conflicting results. Despite such limitations, in managing pregnant women with schizophrenia clinicians should consider an integrated approach that includes: antipsychotic treatment, psychological treatment, optimal dietary approaches for prevention of excessive weight gain and gestational diabetes, meticulous gynecologic and obstetric surveillance, and social and occupational support.

Adenosine kinase and cardiovascular fetal programming in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is a detrimental condition for human pregnancy associated with endothelial dysfunction and endothelial inflammation in the fetoplacental vasculature and leads to increased cardio-metabolic risk in the offspring. In the fetoplacental vasculature, GDM is associated with altered adenosine metabolism. Adenosine is an important vasoactive molecule and is an intermediary and final product of transmethylation reactions in the cell. Adenosine kinase is the major regulator of adenosine levels. Disruption of this enzyme is associated with alterations in methylation-dependent gene expression regulation mechanisms, which are associated with the fetal programming phenomenon. Here we propose that cellular and molecular alterations associated with GDM can dysregulate adenosine kinase leading to fetal programming in the fetoplacental vasculature. This can contribute to the cardio-metabolic long-term consequences observed in offspring after exposure to GDM.