Prenatal Air Pollution Exposure and Placental DNA Methylation Changes: Implications on Fetal Development and Future Disease Susceptibility

Air Pollution-Linked Epigenetic Modifications in Placental DNA: Prognostic Potential for Identifying Future Foetal Anomalies

Prenatal exposure to air pollution is a significant risk factor for the mother and the developing foetus. The accumulation of pollutants in the placenta can cause a self-cascade loop of pro-inflammatory cytokine responses and DNA double-strand breaks. Previous research has shown that airborne particulate matter can damage the epigenome and disturb mitochondrial machinery, ultimately impairing placental function. Mitochondria are essential for preserving cellular homeostasis, energy metabolism, redox equilibrium, and epigenetic reprogramming. As these organelles are subtle targets of environmental exposures, any disruption in the signaling pathways can result in epigenomic instability, which can impact gene expression and mitochondrial function. This, in turn, can lead to changes in DNA methylation, post-translational histone modifications, and aberrant expression of microRNAs in proliferating trophoblast cells. The placenta has two distinct layers, cytotrophoblasts, and syncytiotrophoblasts, each with its mitochondria, which play important roles in preeclampsia, gestational diabetes, and overall health. Foetal nucleic acids enter maternal circulation during placental development because of necrotic, apoptotic, and inflammatory mechanisms. These nucleic acids reflect normal or abnormal ongoing cellular changes during prenatal foetal development. Detecting cell-free DNA in the bloodstream can be a biomarker for predicting negative pregnancy-related outcomes and recognizing abnormalities in foetal growth. Hence, a thorough understanding of how air pollution induces epigenetic variations within the placenta could offer crucial insights into underlying mechanisms and prolonged repercussions on foetal development and susceptibility in later stages of life.

Prenatal exposure to air pollutants and the risk of congenital heart disease: a Korean national health insurance database-based study

Air pollution and heavy metal exposure are emerging public health concerns. Prenatal exposure to air pollutants and heavy metals has been implicated in the development of congenital heart disease (CHD). However, the relationship between exposure to airborne heavy metals and CHD has not yet been investigated. Therefore, in this large population-based study, we investigated the association between air pollutants, including airborne heavy metals, and the risk of CHD using national health insurance claims data from South Korea. Data regarding 1,129,442 newborns and their mothers were matched with air pollutant levels during the first 8 weeks of gestation. In the five-air pollutant model, we found significant positive correlations between prenatal exposure to sulfur dioxide (SO2; odds ratio [OR] 6.843, 95% confidence interval [CI] 5.746-8.149) and cadmium (Cd; OR 1.513, 95% CI 1.187-1.930) and the risk of ventricular septal defects in newborns. This study highlights the association between prenatal exposure to air pollutants, including airborne heavy metals, and an elevated CHD risk. Further research is essential to validate and expand these findings, with the ultimate goal of enhancing public health outcomes.

The status and influencing factors of abnormal fetal pregnancy outcomes in 265 cases in China: a retrospective study

Background

With the advancement of prenatal diagnosis technology, the detection rate of fetal abnormalities continues to increase, imposing a significant burden on both society and families. A retrospective analysis of essential information about pregnant women, such as their pregnancy history and delivery details, is crucial for understanding the primary factors that influence pregnancy outcomes in women with fetal abnormalities. This analysis is of great significance for improving the level of pregnancy management and outcomes in pregnant women with fetal abnormalities.

Objective

To retrospectively analyze the pregnancy outcomes of women with fetal abnormalities and explore the factors that influence these outcomes.

Methods

Pregnant women's pregnancy outcomes were collected from the medical information system and through telephone follow-ups. The chi-square test and logistic regression were used to analyze the factors influencing pregnancy outcomes.

Results

Among 265 pregnant women diagnosed with fetal abnormalities, 190 chose to continue the pregnancy, while 75 chose to terminate it. Pregnant women with multiple fetal abnormalities (OR = 3.774, 95% CI [1.640-8.683]) were more likely to choose termination of pregnancy (TOP), and pregnant women who were advised to terminate their pregnancy or make a careful choice were more likely to terminate the pregnancy (OR = 41.113, 95% CI [11.028-153.267]).

Conclusion

The number of organs involved in fetal abnormalities and treatment recommendations were identified as the primary factors influencing pregnancy outcomes. Improving awareness of maternal health care during pregnancy, early pregnancy screening technology, and a multidisciplinary diagnosis and treatment approach are of great significance in assisting pregnant women in making informed decisions and improving fetal prognosis.

Nitrogen dioxide exposure, attentional function, and working memory in children from 4 to 8 years: Periods of susceptibility from pregnancy to childhood

BACKGROUND

Air pollution exposure during pregnancy and childhood has been linked to executive function impairment in children, however, very few studies have assessed these two exposure periods jointly to identify susceptible periods of exposure. We sought to identify potential periods of susceptibility of nitrogen dioxide (NO2) exposure from conception to childhood on attentional function and working memory in school-aged children.

METHODS

Within the Spanish INMA Project, we estimated residential daily NO2 exposures during pregnancy and up to 6 years of childhood using land use regression models (n = 1,703). We assessed attentional function at 4-6 years and 6-8 years, using the Conners Kiddie Continuous Performance Test and the Attention Network Test, respectively, and working memory at 6-8 years, using the N-back task. We used distributed lag non-linear models to assess the periods of susceptibility of each outcome, adjusting for potential confounders and correcting for multiple testing. We also stratified all models by sex.

RESULTS

Higher exposure to NO2 between 1.3 and 1.6 years of age was associated with higher hit reaction time standard error (HRT-SE) (0.14 ms (95 % CI 0.05; 0.22) per 10 μg/m3 increase in NO2) and between 1.5 and 2.2 years of age with more omission errors (1.02 (95 % CI 1.01; 1.03) of the attentional function test at 4-6 years. Higher exposure to NO2 between 0.3 and 2.2 years was associated with higher HRT-SE (10.61 ms (95 % CI 3.46; 17.75) at 6-8 years only in boys. We found no associations between exposure to NO2 and working memory at 6-8 years.

CONCLUSION

Our findings suggest that NO2 exposure during the first two years of life is associated with poorer attentional function in children from 4 to 8 years of age, especially in boys. These findings highlight the importance of exploring long-term effects of traffic-related air pollution exposure in older age groups.

Prenatal inflammation exposure accelerates lung cancer tumorigenesis in offspring mouse: possible links to IRE1α/XBP1-mediated M2-like polarization of TAMs and PD-L1 up-expression

BACKGROUND

Prenatal inflammation exposure (PIE) can increase the disease susceptibility in offspring such as lung cancer. Our purpose was to investigate the mechanisms of PIE on lung cancer.

METHODS

Prenatal BALB/c mice were exposed to lipopolysaccharide (LPS), and then, their offspring were intraperitoneally instilled with urethane to establish the two-stage lung cancer carcinogenesis model. At the 48 weeks of age, the offspring mice were killed and lung tissues were collected for HE, immunohistochemistry, immunofluorescence, and Luminex MAGPIX®-based assays. CD11b + F4/80 + tumor-associated macrophages (TAMs) were sorted out from lung tumor tissues by cell sorting technique. Flow cytometry was employed to evaluate the extent of M2-like polarization of TAMs and PD-L1 expression.

RESULTS

The offspring of PIE mice revealed more lung lesion changes, including atypical hyperplasia and intrapulmonary metastases. The number of lung nodules, lung organ index, and PCNA, MMP-9 and Vimentin positive cells in lung tissue of PIE group were higher than those of Control group. The increases of mRNA encoding M2 macrophage markers and cytokines in offspring of prenatal LPS-treated mice confirmed the induced effect of PIE on macrophage polarization. Additionally, PIE treatment increased the percentage of CD163 + CD206 + cells in the sorted TAMs. Importantly, endoplasmic reticulum (ER) stress-markers like GRP78/BIP and CHOP, p-IRE1α and XBP1s, and PD-L1 were up-regulated in TAMs from PIE group. Besides, we also observed that IRE1α inhibitor (KIRA6) reversed the M2-like TAMs polarization and metastasis induced by PIE.

CONCLUSIONS

IRE1α/XBP1-mediated M2-like TAMs polarization releases the pro-tumorigenic cytokines and PD-L1 expression, which may be the regulatory mechanism of accelerating lung cancer in offspring of mice undergoing PIE.

Alterations in sperm DNA methylation may as a mediator of paternal air pollution exposure and offspring birth outcomes: Insight from a birth cohort study

Paternal exposure to environmental risk factors influences the offspring health. This study aimed to evaluate the association between paternal air pollution exposure mediated by sperm DNA methylation and adverse birth outcomes in offspring. We recruited 1607 fertile men and their partners from 2014 to 2016 and collected semen samples to detect sperm DNA methylation. Multivariate linear regression and weighted quantile sum regression models were used to assess the associations between paternal air pollution exposure and offspring birth outcomes. A critical exposure window was identified. Reduced representation bisulfite sequencing was used to detect sperm DNA methylation. The results demonstrated that high paternal exposure to PM2.5 (β = -211.31, 95% CI: (-386.37, -36.24)), PM10 (β = -178.20, 95% CI: (-277.13, -79.27)), and NO2 (β = -84.22, 95% CI: (-165.86, -2.57)) was negatively associated with offspring's birthweight, especially in boys. Additionally, an early exposure window of 15-69 days before fertilization was recognized to be the key exposure window, which increased the risk of low birth weight and small for gestational age. Furthermore, paternal co-exposure to six air pollutants contributed to lower birthweight (β = -51.91, 95% CI: (-92.72, -11.10)) and shorter gestational age (β = -1.72, 95% CI: (-3.26, -0.17)) and PM2.5 was the most weighted pollutant. Paternal air pollution exposure resulted in 10,328 differentially methylated regions and the IGF2R gene was the key gene involved in the epigenetic process. These differentially methylated genes were predominantly associated with protein binding, transcriptional regulation, and DNA templating. These findings indicate that spermatogenesis is a susceptible window during which paternal exposure to air pollution affects sperm DNA methylation and the birth outcomes of offspring.

DNA methylation profiles reveal sex-specific associations between gestational exposure to ambient air pollution and placenta cell-type composition in the PRISM cohort study

BACKGROUND

Gestational exposure to ambient air pollution has been associated with adverse health outcomes for mothers and newborns. The placenta is a central regulator of the in utero environment that orchestrates development and postnatal life via fetal programming. Ambient air pollution contaminants can reach the placenta and have been shown to alter bulk placental tissue DNA methylation patterns. Yet the effect of air pollution on placental cell-type composition has not been examined. We aimed to investigate whether the exposure to ambient air pollution during gestation is associated with placental cell types inferred from DNA methylation profiles.

METHODS

We leveraged data from 226 mother-infant pairs in the Programming of Intergenerational Stress Mechanisms (PRISM) longitudinal cohort in the Northeastern US. Daily concentrations of fine particulate matter (PM2.5) at 1 km spatial resolution were estimated from a spatiotemporal model developed with satellite data and linked to womens' addresses during pregnancy and infants' date of birth. The proportions of six cell types [syncytiotrophoblasts, trophoblasts, stromal, endothelial, Hofbauer and nucleated red blood cells (nRBCs)] were derived from placental tissue 450K DNA methylation array. We applied compositional regression to examine overall changes in placenta cell-type composition related to PM2.5 average by pregnancy trimester. We also investigated the association between PM2.5 and individual cell types using beta regression. All analyses were performed in the overall sample and stratified by infant sex adjusted for covariates.

RESULTS

In male infants, first trimester (T1) PM2.5 was associated with changes in placental cell composition (p = 0.03), driven by a decrease [per one PM2.5 interquartile range (IQR)] of 0.037 in the syncytiotrophoblasts proportion (95% confidence interval (CI) [- 0.066, - 0.012]), accompanied by an increase in trophoblasts of 0.033 (95% CI: [0.009, 0.064]). In females, second and third trimester PM2.5 were associated with overall changes in placental cell-type composition (T2: p = 0.040; T3: p = 0.049), with a decrease in the nRBC proportion. Individual cell-type analysis with beta regression showed similar results with an additional association found for third trimester PM2.5 and stromal cells in females (decrease of 0.054, p = 0.024).

CONCLUSION

Gestational exposure to air pollution was associated with placenta cell composition. Further research is needed to corroborate these findings and evaluate their role in PM2.5-related impact in the placenta and consequent fetal programming.

Epigenome-wide meta-analysis of prenatal maternal stressful life events and newborn DNA methylation

Prenatal maternal stressful life events are associated with adverse neurodevelopmental outcomes in offspring. Biological mechanisms underlying these associations are largely unknown, but DNA methylation likely plays a role. This meta-analysis included twelve non-overlapping cohorts from ten independent longitudinal studies (N = 5,496) within the international Pregnancy and Childhood Epigenetics consortium to examine maternal stressful life events during pregnancy and DNA methylation in cord blood. Children whose mothers reported higher levels of cumulative maternal stressful life events during pregnancy exhibited differential methylation of cg26579032 in ALKBH3. Stressor-specific domains of conflict with family/friends, abuse (physical, sexual, and emotional), and death of a close friend/relative were also associated with differential methylation of CpGs in APTX, MyD88, and both UHRF1 and SDCCAG8, respectively; these genes are implicated in neurodegeneration, immune and cellular functions, regulation of global methylation levels, metabolism, and schizophrenia risk. Thus, differences in DNA methylation at these loci may provide novel insights into potential mechanisms of neurodevelopment in offspring.

Air pollution and pregnancy

Increased fossil fuel usage and extreme climate change events have led to global increases in greenhouse gases and particulate matter with 99% of the world's population now breathing polluted air that exceeds the World Health Organization's recommended limits. Pregnant women and neonates with exposure to high levels of air pollutants are at increased risk of adverse health outcomes such as maternal hypertensive disorders, postpartum depression, placental abruption, low birth weight, preterm birth, infant mortality, and adverse lung and respiratory effects. While the exact mechanism by which air pollution exerts adverse health effects is unknown, oxidative stress as well as epigenetic and immune mechanisms are thought to play roles. Comprehensive, global efforts are urgently required to tackle the health challenges posed by air pollution through policies and action for reducing air pollution as well as finding ways to protect the health of vulnerable populations in the face of increasing air pollution.

A Long Way from Steubenville: Environmental Epidemiology in a Rapidly Changing World

This commentary focuses on research that has long been at the core of environmental epidemiology: studies of the health effects of air pollution. It highlights publications in the American Journal of Epidemiology going back more than 50 years that have contributed to the debate about the validity of this research and its meaning for public policy. Technological advances have greatly expanded the toolbox of environmental epidemiologists in terms of measuring and analyzing complex exposures in large populations. Yet, discussions about biases in estimating air pollution health effects have always been and remain intense. Epidemiologists have brought new methodologies and concepts to this research, alleviating some but not all concerns. Here, the focus is on seminal epidemiologic work that established valid links between air pollution exposures and health outcomes and generated data for environmental policies and prevention. With this commentary, I hope to inspire epidemiologists to address many more of the burning environmental health questions-wildfires included-with a similar scientific doggedness. The rapidly changing conditions of our planet are challenging us to innovate and offer solutions, albeit perhaps a little bit faster this time around.

A Retrospective Observational Study Using Administrative Databases to Assess the Risk of Spontaneous Abortions Related to Environmental and Socioeconomic Conditions

Miscarriage is one of the most frequent adverse events that occurs during pregnancy. This retrospective study aimed to verify if the environmental and socioeconomic conditions related to geographical areas where women live, and the socio-demographic and clinical factors play a role in the risk of spontaneous abortion (SA). The analyses were conducted by hospital discharge records (HDRs) from public and private hospitals in Apulia from 1 January 2021 to 31 December 2021. Women with an age over 40 years old had a major risk of SA compared with women under 18 years (OR 2.30, IC95%1.16-4.54). A reduction in the risk of SA was found for women with an endocrinological or metabolic disease (OR 0.28, 95% CI 0.19-0.41), while genetic disease greatly increases the risk (OR 9.63, IC95% 1.98-46.86). The greatest risk of spontaneous abortion was found in the province of Taranto compared to the province of Foggia (OR 2.01, 95% CI 1.52-2.64). The provinces with a higher risk of SA in the multiple comparisons were Taranto, Brindisi, and BAT. Municipalities with socioeconomic disadvantages classified as very low, low, and medium had a higher risk of SA compared to the municipalities with a high disadvantage. In conclusion, our study indicates the possible association between SA rate and environmental conditions. Additionally, the socioeconomic, clinical, and demographic factors were related to the risk of SAs.

Prenatal exposure to environmental air pollution and psychosocial stress jointly contribute to the epigenetic regulation of the serotonin transporter gene in newborns

Antenatal exposures to maternal stress and to particulate matter with an aerodynamic diameter of less than 2.5 μm (PM2.5) have been independently associated with developmental outcomes in early infancy and beyond. Knowledge about their joint impact, biological mechanisms of their effects and timing-effects, is still limited. Both PM2.5 and maternal stress exposure during pregnancy might result in altered patterns of DNA methylation in specific stress-related genes, such as the serotonin transporter gene (SLC6A4 DNAm), that might, in turn, influence infant development across several domains, including bio-behavioral, cognitive and socio-emotional domains. Here, we investigated the independent and interactive influence of variations in antenatal exposures to maternal pandemic-related stress (PRS) and PM2.5 on SLC6A4 DNAm levels in newborns. Mother-infant dyads (N = 307) were enrolled at delivery during the COVID-19 pandemic. Infants' methylation status was assessed in 13 CpG sites within the SLC6A4 gene's region (chr17:28562750-28562958) in buccal cells at birth and women retrospectively report on PRS. PM2.5 exposure throughout the entire gestation and at each gestational trimester was estimated using a spatiotemporal model based on residential address. Among several potentially confounding socio-demographic and health-related factors, infant's sex was significantly associated with infants' SLC6A4 DNAm levels, thus hierarchical regression models were adjusted for infant's sex. Higher levels of SLC6A4 DNAm at 6 CpG sites were found in newborns born to mothers reporting higher levels of antenatal PRS and greater PM2.5 exposure across gestation, while adjusting for infant's sex. These effects were especially evident when exposure to elevated PM2.5 occurred during the second trimester of pregnancy. Several important brain processes (e.g., synaptogenesis and myelination) occur during mid-pregnancy, potentially making the second trimester a sensitive time window for the effects of stress-related exposures. Understanding the interplay between environmental and individual-level stressors has important implications for the improvement of mother-infant health during and after the pandemic.

The methylation profile of IL4, IL5, IL10, IFNG and FOXP3 associated with environmental exposures differed between Polish infants with the food allergy and/or atopic dermatitis and without the disease

Objectives

Epigenetic dynamics has been indicated to play a role in allergy development. The environmental stimuli have been shown to influence the methylation processes. This study investigated the differences in CpGs methylation rate of immune-attached genes between healthy and allergic infants. The research was aimed at finding evidence for the impact of environmental factors on methylation-based regulation of immunological processes in early childhood.

Methods

The analysis of methylation level of CpGs in the IL4, IL5, IL10, IFNG and FOXP3 genes was performed using high resolution melt real time PCR technology. DNA was isolated from whole blood of Polish healthy and allergic infants, with food allergy and/or atopic dermatitis, aged under six months.

Results

The significantly lower methylation level of FOXP3 among allergic infants compared to healthy ones was reported. Additional differences in methylation rates were found, when combining with environmental factors. In different studied groups, negative correlations between age and the IL10 and FOXP3 methylation were detected, and positive - in the case of IL4. Among infants with different allergy symptoms, the decrease in methylation level of IFNG, IL10, IL4 and FOXP3 associated with passive smoke exposure was observed. Complications during pregnancy were linked to different pattern of the IFNG, IL5, IL4 and IL10 methylation depending on allergy status. The IFNG and IL5 methylation rates were higher among exclusively breastfed infants with atopic dermatitis compared to the non-breastfed. A decrease in the IFNG methylation was noted among allergic patients fed exclusively with milk formula. In different study groups, a negative correlation between IFNG, IL5 methylation and maternal BMI or IL5 methylation and weight was noted. Some positive correlations between methylation rate of IL10 and child's weight were found. A higher methylation of IL4 was positively correlated with the number of family members with allergy.

Conclusion

The FOXP3 methylation in allergic infants was lower than in the healthy ones. The methylation profile of IL4, IL5, IL10, IFNG and FOXP3 associated with environmental exposures differed between the studied groups. The results offer insights into epigenetic regulation of immunological response in early childhood.

Evidence for an association of prenatal exposure to particulate matter with clinical severity of Autism Spectrum Disorder

Early-life exposure to air pollutants, including ozone (O₃), particulate matter (PM_2.5 or PM₁₀, depending on diameter of particles), nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) has been suggested to contribute to the etiology of Autism Spectrum Disorder (ASD). In this study, we used air quality monitoring data to examine whether mothers of children with ASD were exposed to high levels of air pollutants during critical periods of pregnancy, and if higher exposure levels may lead to a higher clinical severity in their offspring. We used public data from the Portuguese Environment Agency to estimate exposure to these pollutants during the first, second and third trimesters of pregnancy, full pregnancy and first year of life of the child, for 217 subjects with ASD born between 2003 and 2016. These subjects were stratified in two subgroups according to clinical severity, as defined by the Autism Diagnostic Observational Schedule (ADOS). For all time periods, the average levels of PM_2.5, PM₁₀ and NO₂ to which the subjects were exposed were within the admissible levels defined by the European Union. However, a fraction of these subjects showed exposure to levels of PM_2.5 and PM₁₀ above the admissible threshold. A higher clinical severity was associated with higher exposure to PM_2.5 (p = 0.001), NO₂ (p = 0.011) and PM₁₀ (p = 0.041) during the first trimester of pregnancy, when compared with milder clinical severity. After logistic regression, associations with higher clinical severity were identified for PM_2.5 exposure during the first trimester (p = 0.002; OR = 1.14, 95%CI: 1.05-1.23) and full pregnancy (p = 0.04; OR = 1.07, 95%CI: 1.00-1.15) and for PM₁₀ (p = 0.02; OR = 1.07, 95%CI: 1.01-1.14) exposure during the third trimester. Exposure to PM is known to elicit neuropathological mechanisms associated with ASD, including neuroinflammation, mitochondrial disruptions, oxidative stress and epigenetic changes. These results offer new insights on the impact of early-life exposure to PM in ASD clinical severity.

Ambient air pollution and infant health: a narrative review

The extensive evidence regarding the effects of ambient air pollution on child health is well documented, but limited review summarized their health effects during infancy. Symptoms or health conditions attributed to ambient air pollution in infancy could result in the progression of severe diseases during childhood. Here, we reviewed previous empirical epidemiological studies and/or reviews for evaluating the linkages between ambient air pollution and various infant outcomes including adverse birth outcomes, infant morbidity and mortality, early respiratory health, early allergic symptoms, early neurodevelopment, early infant growth and other relevant outcomes. Patterns of the associations varied by different pollutants (i.e., particles and gaseous pollutants), exposure periods (i.e., pregnancy and postpartum) and exposure lengths (i.e., long-term and short-term). Protection of infant health requires that paediatricians, researchers, and policy makers understand to what extent infants are affected by ambient air pollution, and a call for action is still necessary to reduce ambient air pollution.

Intra-Airway Treatment with Synthetic Lipoxin A4 and Resolvin E2 Mitigates Neonatal Asthma Triggered by Maternal Exposure to Environmental Particles

Particulate matter in the air exacerbates airway inflammation (AI) in asthma; moreover, prenatal exposure to concentrated urban air particles (CAPs) and diesel exhaust particles (DEPs) predisposes the offspring to asthma and worsens the resolution of AI in response to allergens. We previously tested the hypothesis that such exposure impairs the pathways of specialized proresolving mediators that are critical for resolution and found declined Lipoxin A4 (LxA4) and Resolvin E2 (RvE2) levels in the "at-risk" pups of exposed mothers. Here, we hypothesized that supplementation with synthetic LxA4 or RvE2 via the airway can ameliorate AI after allergen exposure, which has not been tested in models with environmental toxicant triggers. BALB/c newborns with an asthma predisposition resultant from prenatal exposure to CAPs and DEPs were treated once daily for 3 days with 750 ng/mouse of LxA4 or 300 ng/mouse of RvE2 through intranasal instillation, and they were tested with the intentionally low-dose ovalbumin protocol that elicits asthma in the offspring of particle-exposed mothers but not control mothers, mimicking the enigmatic maternal transmission of asthma seen in humans. LxA4 and RvE2 ameliorated the asthma phenotype and improved AI resolution, which was seen as declining airway eosinophilia, lung tissue infiltration, and proallergic cytokine levels.

Prenatal exposure to sertraline, associated or not with stress, can negatively program somatic and neurobehavioral development of female rats, and dysregulate reproductive function in adulthood

Selective serotonin reuptake inhibitors (SSRIs) are prescribed to pregnant women for treating mental illnesses. Among the drugs of this class, sertraline (ST) is the antidepressant therapy recommended most frequently. Therefore, this study aimed to evaluate the impact of gestational ST treatment on reproductive parameters and toxicological target organs of rat female offspring, as well as on somatic, reflex and neurobehavioral development, in a model of maternal adversity. Pregnant Wistar rats received vehicle (filtered water) or ST hydrochloride (20 mg/Kg/day diluted in vehicle) by oral gavage, associated or not with restraint stress for 1 h/day from gestational days 13-20. F1 female offspring was evaluated on reproductive parameters, body weight and somatic and reflex milestones from postnatal day (PND) 1. On PNDs 25 and 72, the elevated-plus-maze test was performed, while toxicological target organs were evaluated on PNDs 42 and 80. In utero exposure to ST, regardless of exposure to stress, reduced body weight at birth and affected the somatic development and estrous cycle. The absolute and relative thyroid weights were increased in Stress/ST group during puberty and adulthood, while the percentage of ovarian structures and the absolute uterine weight were altered in this group on PND 80. Prenatal exposure only to ST reduced initial body weight gain, delayed fur development and increased anxiety-like behavior on PND 25. Thus, this experimental study suggests that intrauterine exposure to ST disrupts the fetal environment and can negatively program serotonin-regulated processes. Furthermore, it impacts thyroid weight when associated with stress.

Air Pollution and Birth Outcomes: Health Impact and Economic Value Assessment in Spain

Air pollution is considered an ongoing major public health and environmental issue around the globe, affecting the most vulnerable, such as pregnant women and fetuses. The aim of this study is to estimate the health impact and economic value on birth outcomes, such as low birthweight (LBW), preterm birth (PTB), small for gestational age (SGA), attributable to a reduction of PM₁₀ levels in Spain. Reduction based on four scenarios was implemented: fulfillment of WHO guidelines and EU limits, and an attributable reduction of 15% and 50% in annual PM₁₀ levels. Retrospective study on 288,229 live-born singleton children born between 2009-2010, using data from Spain Birth Registry Statistics database, as well as mean PM₁₀ mass concentrations. Our finding showed that a decrease in annual exposure to PM₁₀ appears to be associated with a decrease in the annual cases of LBW, SGA and PTB, as well as a reduction in hospital cost attributed to been born with LBW. Improving pregnancy outcomes by reducing the number of LBW up to 5% per year, will result in an estimate associated monetary saving of 50,000 to 7,000,000 euros annually. This study agrees with previous literature and highlights the need to implement, and ensure compliance with, stricter policies that regulate the maximum exposure to outdoor PM permitted in Spain, contributing to decreased environmental health risk, especially negative birth outcomes.

Neurodevelopmental toxicity induced by airborne particulate matter

Airborne particulate matter (PM), the primary component associated with health risks in air pollution, can negatively impact human health. Studies have shown that PM can enter the brain by inhalation, but data on the exact quantity of particles that reach the brain are unknown. Particulate matter exposure can result in neurotoxicity. Exposure to PM poses a greater health risk to infants and children because their nervous systems are not fully developed. This review paper highlights the association between PM and neurodevelopmental toxicity (NDT). Exposure to PM can induce oxidative stress and inflammation, potentially resulting in blood-brain barrier damage and increased susceptibility to development of neurodevelopmental disorders (NDD), such as autism spectrum disorders and attention deficit disorders. In addition, human and animal exposure to PM can induce microglia activation and epigenetic alterations and alter the neurotransmitter levels, which may increase risks for development of NDD. However, the systematic comparisons of the effects of PM on NDD at different ages of exposure are deficient. The elucidation of PM exposure risks and NDT in children during the early developmental stages are of great importance. The synthesis of current research may help to identify markers and mechanisms of PM-induced neurodevelopmental toxicity, allowing for the development of strategies to prevent permanent damage of developing brain.

Epigenetics Beyond Fetal Growth Restriction: A Comprehensive Overview

Fetal growth restriction is a pathological condition occurring when the fetus does not reach the genetically determined growth potential. The etiology of fetal growth restriction is expected to be multifactorial and include fetal, maternal, and placental factors, the latter being the most frequent cause of isolated fetal growth restriction. Severe fetal growth restriction has been related to both an increased risk of perinatal morbidity and mortality, and also a greater susceptibility to developing diseases (especially cardio-metabolic and neurological disorders) later in life. In the last decade, emerging evidence has supported the hypothesis of the Developmental Origin of Health and Disease, which states that individual developmental 'programming' takes place via a delicate fine tuning of fetal genetic and epigenetic marks in response to a large variety of 'stressor' exposures during pregnancy. As the placenta is the maternal-fetal interface, it has a crucial role in fetal programming, such that any perturbation altering placental function interferes with both in-utero fetal growth and also with the adult life phenotype. Several epigenetic mechanisms have been highlighted in modulating the dynamic placental epigenome, including alterations in DNA methylation status, post-translational modification of histones, and non-coding RNAs. This review aims to provide a comprehensive and critical overview of the available literature on the epigenetic background of fetal growth restriction. A targeted research strategy was performed using PubMed, MEDLINE, Embase, and The Cochrane Library up to January 2022. A detailed and fully referenced synthesis of available literature following the Scale for the Assessment of Narrative Review Articles guidelines is provided. A variety of epigenetic marks predominantly interfering with placental development, function, and metabolism were found to be potentially associated with fetal growth restriction. Available evidence on the role of environmental exposures in shaping the placental epigenome and the fetal phenotype were also critically discussed. Because of the highly dynamic crosstalk between epigenetic mechanisms and the extra level of complexity in interpreting the final placental transcriptome, a full comprehension of these phenomenon is still lacking and advances in multi-omics approaches are urgently needed. Elucidating the role of epigenetics in the developmental origins of health and disease represents a new challenge for the coming years, with the goal of providing early interventions and prevention strategies and, hopefully, new treatment opportunities.

Exploring the molecular mechanisms underlie the endoplasmic reticulum stress-mediated methylmercury-induced neuronal developmental damage

Methylmercury (MeHg) is a ubiquitous environmental pollutant, which can cross the placenta and blood brain barrier, thus affecting fetal growth and development. Although previous studies have demonstrated that MeHg induces endoplasmic reticulum (ER) stress in rat cerebral cortex and primary neurons, the role of ER stress in MeHg-induced neurodevelopmental toxicity remains unclear. Here, we used ICR pregnant mice and hippocampal neurons cells (HT22 cells) to investigate the molecular mechanism by which MeHg exposure during pregnancy affects neurodevelopment. We found that prenatal MeHg exposure caused developmental delay in offspring, accompanied with ER stress, cell apoptosis, cell cycle arrest and abnormal DNA methylation. Then, we used ER stress specific inhibitor 4-PBA and CHOP siRNA to investigate the role of ER stress on HT22 cells damage caused by MeHg. The results showed that 4-PBA pretreatment restored MeHg-induced axonal shortening and alleviated apoptosis, cell cycle arrest and DNA methylation. At the same time, the activation of CHOP/c-Jun/GADD45A signaling pathway was inhibited, and the interaction between CHOP and c-Jun was weakened. In addition, CHOP siRNA reduced the expression of c-Jun and GADD45A, and relieved DNA methylation levels to some extent. In summary, our study suggested that ER stress induced by MeHg mediated cell apoptosis and cell cycle arrest, and may affect DNA methylation through activation of CHOP/c-Jun/GADD45A signaling pathway, thus leading to neuronal damage.

Effect of maternal ozone exposure before and during pregnancy on wheezing risk in offspring: A birth cohort study in Guangzhou, China

Ozone (O₃) exposure may lead to the development and exacerbation of asthma or wheezing in postnatal children; however, it has rarely been studied before and during pregnancy. Wheezing is one of the most common symptoms when diagnosing of asthma; thus, we investigated the associations of O₃ exposure before and during pregnancy with wheezing in preschool children and the potential susceptible exposure windows from a heavily polluted city in China. This population-based birth cohort study, which included 3725 mother-child pairs from Guangzhou, began in 2016, and the follow-up period ended on July 31, 2020. We used a spatiotemporal land-use-regression model combined with activity patterns to estimate the daily O₃ exposure levels during the pre-pregnancy period and each trimester, and wheezing was recorded by reviewing medical records. We used the Cox proportional hazard model to quantify the effects of O₃ exposure on childhood wheezing adjusted for potential confounders. No significant association was detected between pre-pregnancy exposure to O₃ and childhood wheezing. However, increased ambient O₃ exposures throughout pregnancy and in the second trimester were positively associated with the risk of childhood wheezing, with hazard ratios (HRs) and 95% confident intervals (CIs) per interquartile range (IQR) increment of 1.22 (95% CI: 1.04-1.44) and 1.31 (95% CI: 1.09-1.58), respectively. The effects of maternal O₃ exposure on childhood wheezing risk was stronger when the exposure occurred in the warm conception season (P < 0.05). Significant childhood wheezing risk could be attributable to maternal O₃ exposure, especially during the second trimester and with warm-season conception in Guangzhou. Further cohorts of children, particularly school age children who have more robust asthma diagnoses, should be investigated in the future.

Prenatal Exposure to Traffic-Related Air Pollution and the DNA Methylation in Cord Blood Cells: MOCEH Study

Particulate matter with a diameter of ≤10 µm (PM₁₀) and nitrogen dioxide (NO₂) affect the DNA methylation in the fetus, but epigenetic studies regarding prenatal exposure to air pollution in Asia are lacking. Therefore, this study aimed to assess whether there is any association between the ambient concentrations of PM₁₀ and NO₂ and CpG methylation in the cord blood DNA by using a Korean birth cohort. The concentrations of the air pollutants were incorporated into the final LUR model by using the maternal address data. The methylation level was determined using HumanMethylationEPIC BeadChip and a linear regression analysis model. A multipollutant model including both PM₁₀ and NO₂ and models with single pollutants were used for each trimester exposure. The number of differentially methylated positions was the largest for midpregnancy exposure in both the single pollutant models and the multipollutant regression analysis. Additionally, gene-set analysis regarding midpregnancy exposure revealed four gene ontology terms (cellular response to staurosporine, positive regulation of cytoskeleton organization, neurotransmitter transport, and execution phase of apoptosis). In conclusion, these findings show an association between prenatal PM₁₀ and NO₂ exposure and DNA methylation in several CpG sites in cord blood cells, especially for midpregnancy exposure.

The hypermethylation of FOXP3 gene as an epigenetic marker for the identification of arsenic poisoning risk

Background and Purpose: Arsenic exposure can lead to skin lesions and multiple organ damage, which are not easily reversible and for which there is no effective therapeutics. Identification of reliable epigenetic markers is essential for early recognition of arsenic poisoning risk. Anomalous DNA methylation of immune homeostasis regulator FOXP3 is a critical mechanism for triggering arsenic poisoning. This study aims to explore the value of FOXP3 methylation in the identification of arsenic poisoning risk.Methods: 88 arsenic poisoning subjects and 41 references were recruited. Urinary arsenic contents and FOXP3 methylation in PBLCs was measured by ICP-MS and pyrosequencing, respectively.Results: The results showed that the elevated FOXP3 methylation in PBLCs were associated with the increased levels of urinary arsenic and were positively associated with the increased risk of arsenic poisoning and its progression. The result of mediation analysis revealed that 24.3% of the effect of arsenic exposure on the risk of arsenic poisoning was mediated by increased FOXP3 methylation. Additionally, we constructed a nomogram model with FOXP3 methylation as an epigenetic predictor to assess the probability of individual arsenic poisoning. The model showed a robust ability in the discrimination of arsenic poisoning risk, with an area under receiver operating characteristics curve of 0.897(0.845-0.949) and more than 70% accuracy. The calibration curves and the Harrell concordance index showed that the consistency rate between the probability predicted by the nomogram model and the actual probability is 89.7%.Conclusions: Taken together, we found the great potential of FOXP3 methylation for the identification of arsenic poisoning risk and provided a new approach to the application of epigenetic markers in accurately quantifying the risk of adverse outcomes.