Endocrine disruptors and childhood social impairment

Gestational Exposures to Phthalates and Folic Acid, and Autistic Traits in Canadian Children

BACKGROUND

The etiology of autism spectrum disorder is poorly understood. Few studies have investigated the link between endocrine-disrupting chemicals and autistic traits. We examined the relationship between gestational phthalates and autistic traits in 3- to 4-y-old Canadian children. We also investigated potential effect modification by sex and folic acid supplementation.

METHODS

We enrolled 2,001 women>18 years of age during the first trimester of pregnancy between 2008 and 2011 from 10 cities in Canada. At 3-4 years of age, 610 children underwent neuropsychological assessments including the Social Responsiveness Scale-II (SRS-2) as a measure of autistic traits and social impairment. We measured 11 phthalate metabolites in maternal first trimester urine samples and assessed folic acid supplementation from reported intakes. We estimated covariate-adjusted differences in SRS-2 T-scores with a doubling in phthalate concentrations in 510 children with complete data.

RESULTS

Mean total SRS T-score was 45.3 (SD=6.1). Children with higher gestational exposure to mono-n-butyl (MBP) and mono-3-carboxypropyl (MCPP) concentrations exhibited significantly higher total SRS T-scores, indicating greater overall social impairment, as well as higher scores on subdomains, indicating deficits in social cognition, social communication, social motivation, and restricted interests/repetitive behaviors. A doubling in MBP or MCPP concentrations was associated with 0.6 (95% CI: 0.1, 1.0) and 0.5 (95% CI: 0.1, 0.8) higher total SRS T-scores. Associations were consistently and significantly stronger in boys (βMBP=1.0; 95% CI: 0.4, 1.6; n=252) compared with girls (βMBP=0.1; 95% CI: -0.6, 0.7; n=258) and among children who had lower prenatal folic acid supplementation (<400μg/d) (βMBP=1.3; 95% CI: 0.4, 2.3; n=59) compared with those who had adequate folic acid supplementation (≥400μg/d) (βMBP=0.4; 95% CI: -0.1, 0.8; n=451).

CONCLUSIONS

Higher gestational concentrations of some phthalate metabolites were associated with higher scores of autistic traits as measured by the SRS-2 in boys, but not girls; these small size effects were mitigated by first trimester-of-pregnancy folic acid supplementation. https://doi.org/10.1289/EHP5621.

Perturbation of Nuclear Hormone Receptors by Endocrine Disrupting Chemicals: Mechanisms and Pathological Consequences of Exposure

Much of the early work on Nuclear Hormone Receptors (NHRs) focused on their essential roles as mediators of sex steroid hormone signaling in reproductive development and function, and thyroid hormone-dependent formation of the central nervous system. However, as NHRs display tissue-specific distributions and activities, it is not surprising that they are involved and vital in numerous aspects of human development and essential for homeostasis of all organ systems. Much attention has recently been focused on the role of NHRs in energy balance, metabolism, and lipid homeostasis. Dysregulation of NHR function has been implicated in numerous pathologies including cancers, metabolic obesity and syndrome, Type II diabetes mellitus, cardiovascular disease, hyperlipidemia, male and female infertility and other reproductive disorders. This review will discuss the dysregulation of NHR function by environmental endocrine disrupting chemicals (EDCs), and the associated pathological consequences of exposure in numerous tissues and organ systems, as revealed by experimental, clinical, and epidemiological studies.

Emerging biomarkers in autism spectrum disorder: a systematic review

Autism spectrum disorder (ASD) affects approximately 2% of children in the United States (US) yet its etiology is unclear and effective treatments are lacking. Therapeutic interventions are most effective if started early in life, yet diagnosis often remains delayed, partly because the diagnosis of ASD is based on identifying abnormal behaviors that may not emerge until the disorder is well established. Biomarkers that identify children at risk during the pre-symptomatic period, assist with early diagnosis, confirm behavioral observations, stratify patients into subgroups, and predict therapeutic response would be a great advance. Here we underwent a systematic review of the literature on ASD to identify promising biomarkers and rated the biomarkers in regards to a Level of Evidence and Grade of Recommendation using the Oxford Centre for Evidence-Based Medicine scale. Biomarkers identified by our review included physiological biomarkers that identify neuroimmune and metabolic abnormalities, neurological biomarkers including abnormalities in brain structure, function and neurophysiology, subtle behavioral biomarkers including atypical development of visual attention, genetic biomarkers and gastrointestinal biomarkers. Biomarkers of ASD may be found prior to birth and after diagnosis and some may predict response to specific treatments. Many promising biomarkers have been developed for ASD. However, many biomarkers are preliminary and need to be validated and their role in the diagnosis and treatment of ASD needs to be defined. It is likely that biomarkers will need to be combined to be effective to identify ASD early and guide treatment.

Sex-specific behavioral effects following developmental exposure to tetrabromobisphenol A (TBBPA) in Wistar rats

Tetrabromobisphenol A (TBBPA) has become a ubiquitous indoor contaminant due to its widespread use as an additive flame retardant in consumer products. Reported evidence of endocrine disruption and accumulation of TBBPA in brain tissue has raised concerns regarding its potential effects on neurodevelopment and behavior. The goal of the present study was to examine the impact of developmental TBBPA exposure, across a wide range of doses, on sexually dimorphic non-reproductive behaviors in male and female Wistar rats. We first ran a pilot study using a single TBBPA dose hypothesized to produce behavioral effects. Wistar rat dams were orally exposed using cookie treats to 0 or 0.1 mg TBBPA/kg bw daily from gestational day (GD) 9 to postnatal day (PND) 21 to assess offspring (both sexes) activity and anxiety-related behaviors. Significant effects were evident in females, with exposure increasing activity levels. Thus, this dose was used as the lowest TBBPA dose in a subsequent, larger study conducted as part of a comprehensive assessment of TBBPA toxicity. Animals were exposed to 0, 0.1, 25, or 250 mg TBBPA/kg bw daily by oral gavage starting on GD 6 through PND 90 (dosed dams GD 6 - PND 21, dosed offspring PND 22 - PND 90). Significant behavioral findings were observed for male offspring, with increased anxiety-like behavior as the primary phenotype. These findings demonstrate that exposure to environmental contaminants, like TBBPA, can have sex-specific effects on behavior highlighting the vulnerability of the developing brain.

Prenatal phenol and paraben exposures in relation to child neurodevelopment including autism spectrum disorders in the MARBLES study

BACKGROUND

Environmental phenols and parabens are endocrine disrupting chemicals (EDCs) with the potential to affect child neurodevelopment including autism spectrum disorders (ASD). Our aim was to assess whether exposure to environmental phenols and parabens during pregnancy was associated with an increased risk of clinical ASD or other nontypical development (non-TD).

METHODS

This study included mother-child pairs (N = 207) from the Markers of Autism Risks in Babies - Learning Early Signs (MARBLES) Cohort Study with urinary phenol and paraben metabolites analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) from repeated pregnancy urine samples. Because family recurrence risks in siblings are about 20%, MARBLES enrolls pregnant women who already had a child with ASD. Children were clinically assessed at 3 years of age and classified into 3 outcome categories: ASD, non-TD, or typically developing (TD). Single analyte analyses were conducted with trinomial logistic regression and weighted quantile sum (WQS) regression was used to test for mixture effects.

RESULTS

Regression models were adjusted for pre-pregnancy body mass index, prenatal vitamin use (yes/no), homeowner status (yes/no), birth year, and child's sex. In single chemical analyses phenol exposures were not significantly associated with child's diagnosis. Mixture analyses using trinomial WQS regression showed a significantly increased risk of non-TD compared to TD (OR = 1.58, 95% CI: 1.04, 2.04) with overall greater prenatal phenol and paraben metabolites mixture. Results for ASD also showed an increased risk, but it was not significant.

DISCUSSION

This is the first study to provide evidence that pregnancy environmental phenol exposures may increase the risk for non-TD in a high-risk population.

Endogenous Retroviruses Activity as a Molecular Signature of Neurodevelopmental Disorders

Human endogenous retroviruses (HERVs) are genetic elements resulting from relics of ancestral infection of germline cells, now recognized as cofactors in the etiology of several complex diseases. Here we present a review of findings supporting the role of the abnormal HERVs activity in neurodevelopmental disorders. The derailment of brain development underlies numerous neuropsychiatric conditions, likely starting during prenatal life and carrying on during subsequent maturation of the brain. Autism spectrum disorders, attention deficit hyperactivity disorders, and schizophrenia are neurodevelopmental disorders that arise clinically during early childhood or adolescence, currently attributed to the interplay among genetic vulnerability, environmental risk factors, and maternal immune activation. The role of HERVs in human embryogenesis, their intrinsic responsiveness to external stimuli, and the interaction with the immune system support the involvement of HERVs in the derailed neurodevelopmental process. Although definitive proofs that HERVs are involved in neurobehavioral alterations are still lacking, both preclinical models and human studies indicate that the abnormal expression of ERVs could represent a neurodevelopmental disorders-associated biological trait in affected individuals and their parents.

Cohort profile: the Neonatal Intensive Care Unit Hospital Exposures and Long-Term Health (NICU-HEALTH) cohort, a prospective preterm birth cohort in New York City

PURPOSE

The Neonatal Intensive Care Unit Hospital Exposures and Long-Term Health (NICU-HEALTH) longitudinal preterm birth cohort studies the impact of the NICU exposome on early-life development. NICU-HEALTH collects multiple biospecimens, complex observational and survey data and comprehensive multisystem outcome assessments to allow measurement of the impact of modifiable environmental exposures during the preterm period on neurodevelopmental, pulmonary and growth outcomes.

PARTICIPANTS

Moderately preterm infants without genetic or congenital anomalies and their mothers are recruited from an urban academic medical centre level IV NICU in New York City, New York, USA. Recruitment began in 2011 and continues through multiple enrolment phases to the present with goal enrolment of 400 infants. Follow-up includes daily data collection throughout the NICU stay and six follow-up visits in the first 2 years. Study retention is 77% to date, with the oldest patients turning age 8 in 2019.

FINDINGS TO DATE

NICU-HEALTH has already contributed significantly to our understanding of phthalate exposure in the NICU. Phase I produced the first evidence of the clinical impact of phthalate exposure in the NICU population. Further study identified specific sources of exposure to clinically relevant phthalate mixtures in the NICU.

FUTURE PLANS

Follow-up from age 3 to 12 is co-ordinated through integration with the Environmental Influences on Child Health Outcomes (ECHO) programme. The NICU-HEALTH cohort will generate a wealth of biomarker, clinical and outcome data from which future studies of the impact of early-life chemical and non-chemical environmental exposures can benefit. Findings from study of this cohort and other collaborating environmental health cohorts will likely translate into improvements in the hospital environment for infant development.

TRIAL REGISTRATION NUMBERS

This observational cohort is registered with ClinicalTrials.gov (NCT01420029 and NCT01963065).

Prenatal maternal and childhood bisphenol a exposure and brain structure and behavior of young children

BACKGROUND

Bisphenol A (BPA) is commonly used in the manufacture of plastics and epoxy resins. In North America, over 90% of the population has detectable levels of urinary BPA. Human epidemiological studies have reported adverse behavioral outcomes with BPA exposure in children, however, corresponding effects on children's brain structure have not yet been investigated. The current study examined the association between prenatal maternal and childhood BPA exposure and white matter microstructure in children aged 2 to 5 years, and investigated whether brain structure mediated the association between BPA exposure and child behavior.

METHODS

Participants were 98 mother-child pairs who were recruited between January 2009 and December 2012. Total BPA concentrations in spot urine samples obtained from mothers in the second trimester of pregnancy and from children at 3-4 years of age were analyzed. Children participated in a diffusion magnetic resonance imaging (MRI) scan at age 2-5 years (3.7 ± 0.8 years). Associations between prenatal maternal and childhood BPA and children's fractional anisotropy and mean diffusivity of 10 isolated white matter tracts were investigated, controlling for urinary creatinine, child sex, and age at the time of MRI. Post-hoc analyses examined if alterations in white matter mediated the relationship of BPA and children's scores on the Child Behavior Checklist (CBCL).

RESULTS

Prenatal maternal urinary BPA was significantly associated with child mean diffusivity in the splenium and right inferior longitudinal fasciculus. Splenium diffusivity mediated the relationship between maternal prenatal BPA levels and children's internalizing behavior (indirect effect: β = 0.213, CI [0.0167, 0.564]). No significant associations were found between childhood BPA and white matter microstructure.

CONCLUSIONS

This study provides preliminary evidence for the neural correlates of BPA exposure in humans. Our findings suggest that prenatal maternal exposure to BPA may lead to alterations in white matter microstructure in preschool aged children, and that such alterations mediate the relationship between early life exposure to BPA and internalizing problems.

Prenatal Exposure to Phthalates and Neurodevelopment in the CHAMACOS Cohort

BACKGROUND

Previous studies suggest that prenatal exposure to phthalates, ubiquitous synthetic chemicals, may adversely affect neurodevelopment. However, data are limited on how phthalates affect cognition, executive function, and behavioral function into adolescence.

OBJECTIVE

We aimed to investigate associations of prenatal phthalate exposure with neurodevelopment in childhood and adolescence in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study.

METHODS

We examined associations between maternal urinary phthalate metabolite concentrations measured twice during pregnancy and a range of neurodevelopmental outcomes from ages 7 through 16 y in the CHAMACOS birth cohort (n=334). We used age-specific linear regression models and generalized estimating equation models to assess longitudinal effects and examined differences by sex.

RESULTS

Phthalate metabolites were detected in 88%-100% of samples, depending on the metabolite. Associations of phthalates with neurodevelopmental outcomes were largely null with some noteworthy patterns. Higher prenatal concentrations of metabolites of low-molecular weight phthalates (ΣLMW) were associated with more self-reported hyperactivity [β=0.8, 95% confidence interval (CI): 0.1, 1.4 per 2-fold increase in ΣLMW phthalates], attention problems (β=1.5, 95% CI: 0.7, 2.2), and anxiety (β=0.9, 95% CI: 0.0, 1.8) at age 16. We observed sex-specific differences for the sums of high-molecular-weight and di(2-ethylhexyl) metabolites and cognitive outcomes (e.g., β for Full-Scale IQ for boys=-1.9, 95% CI: -4.1, 0.3 and -1.7, 95% CI: -3.8, 0.3, respectively; β for girls=1.8, 95% CI: 0.1, 3.4 and 1.6, 95% CI: 0.0, 3.2, respectively; p-int=0.01 for both).

CONCLUSION

We found predominantly null associations of prenatal phthalates with neurodevelopment in CHAMACOS, and weak associations of ΣLMW phthalates with internalizing and externalizing behaviors in adolescence. No previous studies have examined associations of prenatal phthalate exposure with neurodevelopment into adolescence, an important time for manifestations of effects. https://doi.org/10.1289/EHP5165.

Prenatal and early postnatal phthalate exposure and child neurodevelopment at age of 7 years - Polish Mother and Child Cohort

Phthalates are among the most frequently investigated environmental chemicals influencing children's health and particularly their neuropsychological development. However, the reported effects of these compounds on child behavior, cognitive and psychomotor outcomes are not fully consistent. The aim of this study is to evaluate the associations between prenatal and early postnatal phthalate exposures and child neurodevelopment at age of 7 years. A total of 134 mother-child pairs from Polish Mother and Child Cohort (REPRO_PL) constitute the basis for current analysis. Eleven phthalate metabolites were measured in urine samples collected from mothers in the 3rd trimester of pregnancy and from children at the age of 2 years. Child neuropsychological development at early school age (7 years) was assessed by both the Strengths and Difficulties Questionnaire (SDQ) filled by mothers and the Polish adaptation of the Intelligence and Development Scales (IDS) performed by psychologists. Mono-ethyl phthalate (MEP) concentration during pregnancy was significantly associated with increased risk of peer relationship problems in SDQ (OR = 2.7, p = 0.03). The results of the IDS analyses focused on child's cognitive and psychomotor development are not fully conclusive. Negative associations were evident between some phthalates in early childhood period and fluid intelligence and cognition (MEP: β = -5.2; p = 0.006; β = -4.2; p = 0.006; mono-n-butyl phthalate (MnBP): β = -4.9; p = 0.03; β = -4.0; p = 0.03; respectively), while positive associations have been found in the prenatal period (mono-2-ethyl-5-oxo-hexyl phthalate (oxo-MEHP): β = 3.6; p = 0.03 for fluid intelligence; β = 2.9; p = 0.03 for cognition). Further studies are required in order to elucidate which are the most critical periods of phthalate exposure on children's neurodevelopmental outcomes.

An epigenome-wide analysis of cord blood DNA methylation reveals sex-specific effect of exposure to bisphenol A

Exposure to bisphenol A (BPA) in utero is associated with adverse health outcome of the offspring. Differential DNA methylation at specific CpG sites may link BPA exposure to health impacts. We examined the association of prenatal BPA exposure with genome-wide DNA methylation changes in cord blood in 277 mother-child pairs in the Hokkaido Study on Environment and Children’s Health, using the Illumina HumanMethylation 450 BeadChip. We observed that a large portion of BPA-associated differentially methylated CpGs with p-value < 0.0001 was hypomethylated among all newborns (91%) and female infants (98%), as opposed to being hypermethylated (88%) among males. We found 27 and 16 CpGs with a false discovery rate (FDR) < 0.05 in the analyses for males and females, respectively. Genes annotated to FDR-corrected CpGs clustered into an interconnected genetic network among males, while they rarely exhibited any interactions in females. In contrast, none of the enrichment for gene ontology (GO) terms with FDR < 0.05 was observed for genes annotated to the male-specific CpGs with p < 0.0001, whereas the female-specific genes were significantly enriched for GO terms related to cell adhesion. Our epigenome-wide analysis of cord blood DNA methylation implies potential sex-specific epigenome responses to BPA exposure.

Bisphenol-A induces neurodegeneration through disturbance of intracellular calcium homeostasis in human embryonic stem cells-derived cortical neurons

Bisphenol-A (BPA) is a representative exogenous endocrine disruptor, which is extensively composed in plastic products. Due to the capability of passing through the blood-brain barrier, evidence has linked BPA exposure with multiple neuropsychological dysfunctions, neurobehavioral disorders and neurodegenerative diseases. However, the underlying mechanism by which BPA induces neurodegeneration still remains unclear. Our study used human embryonic stem cells-derived human cortical neurons (hCNs) as a cellular model to investigate the adverse neurotoxic effects of BPA. hCNs were treated with 0, 0.1, 1 and 10 μM BPA for 14 days. Impacts of BPA exposure on cell morphology, cell viability and neural marker (MAP2) were measured for evaluating the neurodegeneration. The intracellular calcium homeostasis, reactive oxygen species (ROS) generation and organelle functions were also taken into consideration. Results revealed that chronic exposure of BPA damaged the neural morphology, induced neuronal apoptosis and decreased MAP2 expression at the level of both transcription and translation. The intracellular calcium levels were elevated in hCNs after BPA exposure through NMDARs-nNOS-PSD-95 mediating. Meanwhile, BPA led to oxidative stress by raising the ROS generation and attenuating the antioxidant defense in hCNs. Furthermore, BPA triggered ER stress and increased cytochrome c release by impairing the mitochondrial function. Ultimately, BPA triggered the cell apoptosis by regulating Bcl-2 family and caspase-dependent signaling pathway. Taken together, BPA exerted neurotoxic effects on hCNs by eliciting apoptosis, which might due to the intracellular calcium homeostasis perturbation and cell organellar dysfunction.

Bisphenol-A exposure induced neurotoxicity in glutamatergic neurons derived from human embryonic stem cells

Bisphenol-A (BPA) is a lipophilic, organic, synthetic compound that has been used as an additive in polycarbonate plastics manufacturing since 1957. Studies have shown that BPA interferes with the development and functions of the brain, but little is known about the effects of BPA on human glutamatergic neurons (hGNs) at the molecular and cellular levels. We investigated the impact of chronic exposure to BPA to hGNs derived from human embryonic stem cells (hESCs). The results showed that chronic exposure of different concentrations of BPA (0, 0.1, 1.0 and 10 μM) to hGNs for 14 days reduced neurite outgrowth in a concentration-dependent manner. Using presynaptic protein synaptophysin and postsynaptic protein PSD-95 antibodies, immunofluorescence staining and western blotting results indicated that BPA exposure altered the morphology of dendritic spines and increased synaptophysin and PSD-95 expression. Furthermore, BPA exposure at concentrations higher than 1.0 μM resulted in the increase of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) expression and deterioration of dendritic spines. In addition, our results suggested that these BPA mediated neurotoxicity effects were due to an increased production of reactive nitrogen species (RNS) and reactive oxygen species (ROS) via increased nitric oxide synthase (iNOS), neuronal nitric oxide synthase (nNOS), 3-nitrotyrosine expression and Ca²⁺ influx. These results imply that hESC-based neuronal differentiation is an excellent cellular model to examine BPA-induced neurotoxicity on human neurons at the cellular and molecular level.

Endocrine disrupting chemical exposure and maladaptive behavior during adolescence

BACKGROUND

Studies suggest that exposure to endocrine disrupting chemicals (EDCs), including phthalates, phenols, and parabens may influence childhood behavior, but the relationship during adolescence has not been assessed.

OBJECTIVE

We investigated the association between urinary biomarker concentrations of potential EDCs, including some phthalate and bisphenol A replacement chemicals, and behavior in adolescents.

METHODS

Participants were from the New Bedford Cohort (NBC), a prospective birth cohort of residents near the New Bedford Harbor Superfund site in Massachusetts. We measured urinary concentrations of 16 phthalate metabolites or replacements, 8 phenols, and 4 parabens in 205 NBC adolescents and estimated associations between select EDCs and adolescent behavior assessed with the Behavior Assessment System for Children, Second Edition -Teacher Rating Scale (BASC-2). Of note, up to 32 of the 205 in our assessment had missing outcome information imputed.

RESULTS

Increased urinary concentrations of the sum of 11 antiandrogenic phthalate metabolites were associated with an increase in maladaptive behaviors (Externalizing Behavior, Behavioral Symptoms Index, and Developmental Social Disorders or DSD), and a decrease in Adaptive Skills. For example, a doubling of urinary concentrations of antiandrogenic phthalate metabolites was associated with an increased risk of Externalizing Behavior (RR=1.04; 95% CI: 1.01-1.08). While associations were generally stronger in males, sex differences were not statistically significant. Urine concentrations of phenols and parabens were not associated with adverse behavior.

CONCLUSION

Our findings support the importance of exposure to antiandrogenic phthalates during adolescence as a potential correlate of maladaptive behaviors including Externalizing Behavior, DSD behaviors, and decrements in Adaptive Skills.

The association between prenatal exposure to phthalates and cognition and neurobehavior of children-evidence from birth cohorts

BACKGROUND

Phthalate have been detected widely in the environment; while several studies have indicated that prenatal phthalate exposure has adverse effects on neurodevelopment, the results were inconsistent.

OBJECTIVE

We aimed to determine the current research status of the relationship between prenatal exposure to different types of phthalate and cognition and behavioral development in children. We conducted a systematic review to evaluate the current state of knowledge.

METHODS

We systematically searched PubMed, Web of Science, and EMBASE electronic databases up to May 2018 with manual searches of the references of retrieved publications and relevant reviews. Only birth cohort studies that reported on the association between phthalate exposure and cognitive or behavioral development were included in this review. We evaluated the risk of bias for each of the included studies using a modified instrument based on the Cochrane Collaboration's "Risk of Bias" tool.

RESULT

Twenty-six birth cohort studies met our inclusion criteria, nine of which investigated the impact of phthalate exposure during pregnancy on cognition, 13 on neurobehavior, and 4 on both cognition and neurobehavior. However, ten articles reported that the effect of prenatal exposure to phthalates on cognitive development was statistically significant, 15 articles reported that the effect of prenatal exposure to phthalates on neurobehavior was statistically significant. The effect of prenatal phthalate exposure on neurodevelopment differed according to sex, but the results are inconsistent, for instance, among the five studies investigating the association between mental development index (MDI) and Mono-n-butyl phthalate (MnBP), two of them showed a significantly decreasing MDI scores with increasing concentrations of MnBP among girls, but among boys one study showed the inverse association, another showed the positive association.

CONCLUSION

Di(2-ethylhexyl) phthalate, dibutyl phthalate, butyl-benzyl phthalate and di-ethyl phthalate exposure during pregnancy was associated with lower cognitive scores and worse behavior in offspring, and sex-specific effects on cognitive, psychomotor, and behavioral development were identified, especially the impact of phthalate exposure on neurobehavior in boys.

Environmental exposures and cancer: using the precautionary principle

Since the 1970s, more than 87,000 chemicals have been approved for commercial use. Yet of those thousands of chemicals, only just over one thousand have been formally examined and graded for their carcinogenic potential. Of those, five hundred have been found worthy of being graded on a cautiously worded scale ranging from “known” carcinogens to “possibly” carcinogenic. In addition to carcinogenic substances, a new field has emerged researching how environmental toxins cause endocrine or hormonal disruption. A class of these compounds known as endocrine-disrupting chemicals (EDCs) can be found in our food, our environment, and in the products we put on our bodies. Rather than being directly linked to causing cancer, like substances such as asbestos, EDCs influence our health by mimicking or enhancing or changing metabolic regulation. These compounds interfere with hormone production and metabolism in ways that may—especially over the long term—create biological conditions that make us more susceptible to cancer and other diseases. Most of us are exposed to a cocktail of environmental toxins on an ongoing daily basis and at a relatively low level of exposure. Given the lax regulation of chemicals and the reactionary approach of government regulators, it is up to the consumer to be diligent about reading labels and making healthy choices to limit exposure to chemicals and toxins. It is ideal to adopt the Precautionary Principle: until a chemical is found to be harmless, try to not use it. The precautionary principle means that you are maintaining awareness of what you are putting on and in your body and taking steps to avoid exposing yourself unnecessarily to toxins in your household and environment.

Perinatal Exposure to Environmental Endocrine Disruptors in the Emergence of Neurodevelopmental Psychiatric Diseases: A Systematic Review

Background: Exposure to endocrine disruptors is on the rise, with new compounds regularly incriminated. In animals and humans, this exposure during critical developmental windows has been associated with various developmental abnormalities, including the emergence of psychiatric disorders. We aimed to review the association between perinatal endocrine disruptor exposure and neurodevelopmental disorders in humans, focusing on cognitive and psychiatric disorders. Methods: We performed a systematic review with key words referring to the fields of neurodevelopment and endocrine disruptors. We reviewed 896 titles, choosing studies on the basis of titles and abstracts. We searched through the methodology sections to find perinatal exposure and neurodevelopmental disorders, following the categories indicated in the Diagnostic and Statistic Manual of Mental Disorders (5^th edition). References in some studies brought us to a total of 47 studies included here. Results: Convergent studies report an association between exposure to endocrine disruptors and autism spectrum disorder, attention-deficit hyperactivity disorder, global developmental delay, intellectual disability, communication disorders and unspecified neurodevelopmental disorders. Conclusion: Sufficient data exist to report that exposure to some endocrine disruptors is a risk factor for the emergence of neurodevelopmental disorders. Studying endocrine disruptor exposure in humans is still associated with some limits that are difficult to overcome.

[Association of exposure to polycyclic aromatic hydrocarbons during pregnancy with autism spectrum disorder-related behaviors in toddlers: a birth cohort study]

OBJECTIVE

To study the association of exposure to polycyclic aromatic hydrocarbons (PAH) during pregnancy and autism spectrum disorder (ASD)-related behaviors in toddlers.

METHODS

A total of 348 toddlers who had accepted the measurement of PAH-DNA adduct in umbilical cord blood and evaluation of behavior problems at the age of 36 months were enrolled in this birth cohort study. Child Behavior Checklist (CBCL) and Autism Behavior Checklist (ABC) were used to evaluate behavior problems at the age of 36 months. The correlation of the concentration of PAH-DNA adduct in umbilical cord blood with CBCL and ABC scores at the age of 36 months were analyzed.

RESULTS

The detection rate of PAH-DNA adduct in umbilical cord blood was 52.3%, and the median concentration was 0.68 ng/mL. The median total scores of CBCL and ABC scales were 23 and 8 respectively. In children aged 36 months, the concentration of PAH-DNA adduct was positively correlated with the score of social withdrawal in the CBCL scale (r_s=0.205, P<0.05), the total score of the ABC scale (r_s=0.412, P<0.05), and the self-care score of the ABC scale (r_s=0.355, P<0.05). The concentration of PAH-DNA adduct was closely associated with the total score of the ABC scale in children aged 36 months (β=0.122, P<0.05).

CONCLUSIONS

PAH exposure during pregnancy may be a risk factor for ASD-related behaviors in toddlers. Effective reduction of PAH exposure during pregnancy and detection of PAH-DNA adduct in neonatal umbilical cord blood are of vital importance for early prevention, screening and intervention of ASD.

Sex Differences in the Effects of Prenatal Bisphenol A Exposure on Genes Associated with Autism Spectrum Disorder in the Hippocampus

Autism spectrum disorder (ASD) is a neurodevelopmental disorder inexplicably biased towards males. Although prenatal exposure to bisphenol A (BPA) has recently been associated with the ASD risk, whether BPA dysregulates ASD-related genes in the developing brain remains unclear. In this study, transcriptome profiling by RNA-seq analysis of hippocampi isolated from neonatal pups prenatally exposed to BPA was conducted and revealed a list of differentially expressed genes (DEGs) associated with ASD. Among the DEGs, several ASD candidate genes, including Auts2 and Foxp2, were dysregulated and showed sex differences in response to BPA exposure. The interactome and pathway analyses of DEGs using Ingenuity Pathway Analysis software revealed significant associations between the DEGs in males and neurological functions/disorders associated with ASD. Moreover, the reanalysis of transcriptome profiling data from previously published BPA studies consistently showed that BPA-responsive genes were significantly associated with ASD-related genes. The findings from this study indicate that prenatal BPA exposure alters the expression of ASD-linked genes in the hippocampus and suggest that maternal BPA exposure may increase ASD susceptibility by dysregulating genes associated with neurological functions known to be negatively impacted in ASD, which deserves further investigations.

Urinary concentrations of phenols and phthalate metabolites reflect extracellular vesicle microRNA expression in follicular fluid

BACKGROUND

Phenols and phthalates are potential endocrine disrupting chemicals (EDCs) that are associated with adverse health outcomes. These EDCs dysregulate a number of biomolecules and pathways, including microRNAs. MicroRNAs can be carried in transport systems called extracellular vesicles (EVs) that are present in most biofluids. EVs in the follicular fluid, which fills the ovarian follicle and influences oocyte developmental competency, carry microRNAs (EV-miRNAs) that have been associated with In Vitro Fertilization (IVF) outcomes. However, it remains unclear whether EDCs affect EV-miRNAs in follicular fluid.

OBJECTIVES

This study sought to determine whether urinary concentrations of phenols and phthalates biomarkers are associated with EV-miRNAs expression in follicular fluid collected from women undergoing IVF treatment.

METHODS

This cross-sectional study included 130 women recruited between January 2014 and August 2016 in a tertiary university-affiliated hospital. Participants provided urine samples during ovarian stimulation and on the day of oocyte retrieval. We assessed urinary concentrations of five phenols, eight phthalate metabolites, and one phthalate alternative metabolite. EV-miRNAs were isolated from follicular fluid and their expression profiles were measured using the TaqMan Open Array® Human microRNA panel. We fitted multivariable linear regression models and principal component analysis to examine associations between individual and molar sums of exposure biomarkers and EV-miRNAs.

RESULTS

Of 754 miRNAs tested, we detected 133 EV-miRNAs in the microRNA array which expressed in at least 50% of the follicular fluid samples. After adjusting for multiple testing, we identified eight EV-miRNAs associated with individual phenols and phthalate metabolites, as well as molar ΣDEHP that met a q < 0.10 false-discovery rate (FDR) threshold. Hsa-miR-125b, hsa-miR-106b, hsa-miR-374a, and hsa-miR15b was associated with mono(2-ethylhexyl) phthalate concentrations, hsa-let-7c with concentrations mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP), mono-2-ethyl-5-carboxypentyl phthalate (MECPP), and the sum of metabolites of di(2-ethylhexyl) phthalate, hsa-miR-24 with mono-n-butyl phthalate concentrations, hsa-miR-19a with cyclohexane-1,2-dicarboxylic acid monohydroxy isononyl ester (MHiNCH), and hsa-miR-375 with ethyl paraben concentrations. Using Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, gene targets and pathways of these EV-miRNAs were predicted in silico and 17 KEGG FDR-significant pathways related to follicular development and oocyte competence were identified.

CONCLUSIONS

Our results show that urinary concentrations of select phenol and phthalate metabolites are correlated with altered EV-miRNAs expression in follicular fluid. These findings may provide insight regarding the molecular mechanisms underlying adverse effects of phenol and phthalate exposure on female fertility.

Autism spectrum disorders, endocrine disrupting compounds, and heavy metals in amniotic fluid: a case-control study

Background

Evidence has indicated that some non-inherited factors such as exposure to environmental pollutants are associated with neurodevelopment disorders like autism spectrum disorder (ASD). Studies report that endocrine disrupting compounds (EDCs), including polychlorinated biphenyls, organochlorine pesticides, perfluoroalkyl substances (PFAS), and some metals, have adverse effects on the fetal neurodevelopment. The aim of this study was to measure the amniotic fluid (AF) levels of EDCs and metals as well as the receptor transactivities induced by AF and investigate the possible link between prenatal exposure to EDCs and heavy metals and ASD risk.

Methods

In this case-control study, we included AF samples of 75 ASD cases and 135 frequency-matched controls and measured the levels of the endogenous sex hormones, PFAS, and elements including heavy metals. The combined effect of endogenous hormones and EDCs on the receptor of estrogen (ER), androgen (AR), aryl hydrocarbon (AhR), and thyroid hormone-like activity were also determined and expressed as receptor ligand equivalents. We assessed the associations of AF levels of chemicals, sex hormones, and receptor activities with ASD risk using unconditional logistical regression analyses. To control for multiple comparisons, the false discovery rate (FDR) was used and q values less than 0.25 were designated as statistical significance.

Results

PFAS and metals were detectable in AF samples. The ASD cases had significantly lower AF levels of PFAS than controls, and the adjusted odds ratio (OR) was 0.410 (95% CI 0.174, 0.967; p = 0.042; FDR q _value = 0.437) for perfluorooctane sulfonate (PFOS). The principal component, including PFAS congeners, copper, iron, and estrogenic activity, was significantly inversely associated with ASD risk (adjusted OR = 0.100; 95% CI 0.016, 0.630; p = 0.014; FDR q _value = 0.098).Testosterone level in AF weakly associated with ASD risk (adjusted OR = 1.002; 95% CI 1.000, 1.004; p = 0.05). However, after multiple comparison correction, the association was not significant (FDR q _value = 0.437). No significant associations between AF-induced receptor transactivities and ASD risk were observed. The adjusted OR was 2.176 (95%CI 0.115, 41.153) for the ratio of the combined androgenic activity to combined estrogenic activity.

Conclusions

The presence of PFAS and heavy metals in AF indicates that they can cross the placenta. The inverse association between levels of PFAS congeners in AF and ASD risk might relate to the weak estrogenic activities and anti-androgenic activities of PFAS.The observed tendency of positive association between the ratio of combined androgenic effect to the combined estrogenic effect and ASD risk needs further studies to explore whether EDCs together with endogenous hormones play a role in the development of ASD.

Personal care product use as a predictor of urinary concentrations of certain phthalates, parabens, and phenols in the HERMOSA study

Use of personal care products, such as makeup, soaps, and sunscreen, may expose adolescent girls to potential endocrine disruptors, including phthalates, parabens, and other phenols. We evaluated the relationship between recent self-reported personal care product use and concentrations for urinary metabolites of phthalates, parabens, triclosan, and benzophenone-3 (BP-3) in 100 Latina adolescents. Girls who reported using makeup every day vs. rarely/never had higher urinary concentrations of monoethyl phthalate (MEP) (102.2 ng/mL vs. 52.4 ng/mL, P-value: 0.04), methyl paraben (MP) (120.5 ng/mL vs. 13.4 ng/mL, P-value < 0.01), and propyl paraben (PP) (60.4 ng/mL vs. 2.9 ng/mL, P-value < 0.01). Girls who reported recent use of specific makeup products, including foundation, blush, and mascara, had higher urinary concentrations of MEP, mono-n-butyl phthalate (MBP), MP, and PP. Use of Colgate Total toothpaste was associated with 86.7% higher urinary triclosan concentrations. Use of sunscreen was associated with 57.8% higher urinary concentrations of BP-3. Our findings suggest that personal care product use is associated with higher exposure to certain phthalates, parabens, and other phenols in urine. This may be especially relevant in adolescent girls who have high use of personal care products during a period of important reproductive development.

Fetal toxicology

Toxic chemicals, either from natural sources or man-made, are ubiquitous in our environment. Many of the synthetic chemicals make life more comfortable and therefore production continues to grow. Simultaneously with the increase in production, an increase in neurodevelopmental disorders has been observed. Some chemicals are not biodegradable or have a very long half-life time and, despite the fact that production of a number of those chemicals has been severely reduced, they are still ubiquitous in the environment. Fetal exposure to toxic chemicals is dependent on maternal exposure to those chemicals and the developing stage of the fetus. Human evidence from epidemiologic studies is described with regard to the effect of prenatal exposure to various groups of neurotoxicants (alcohol, particulate fine matter, metals, and endocrine disrupting chemicals) on neurobehavior development. Data indicate that prenatal exposure to alcohol, polycyclic aromatic hydrocarbons, lead, methylmercury (MeHg), organophosphate pesticides (OPPs), and polychlorinated biphenyl ethers (PBDEs) impair cognitive development, whereas exposure to alcohol, MeHg, organochlorine pesticides and OPPs, polychlorinated biphenyls, PBDEs, and bisphenol A increases the risk of developing either attention deficit/hyperactivity and/or autism spectrum disorders. Psychomotor development appears to be less affected. However, data are not conclusive, which may depend on the assessment of exposure and the exposure level, among other factors.

Priority and emerging pollutants in the Moscow rain

Air quality is a worldwide problem. Nowadays, thousands of chemicals may be found in the atmosphere from biogenic and anthropogenic sources due to numerous atmospheric reactions. Unfortunately, throughout the world only a small group of organic compounds is monitored on a regular basis. Therefore, an important environmental task involves discovering the most important pollutants for particular cities and regions for regular monitoring in the future. Direct measurements of contaminants in the atmosphere are not always efficient as air represents an extremely dynamic medium. Thus indirect analysis by using precipitations becomes a more popular method of environmental analysis. Over 700 organic compounds belonging to the various classes of chemicals were identified in the Moscow rainwater samples collected in the spring of 2017 using GC/MS instruments including the most analytically powerful modern technique - GC × GC-HRMS. Here we report the nature and levels of 160 priority pollutants and emerging contaminants belonging to the most relevant classes from the environmental point of view: polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organophosphates, dialkylphthalates, phenols, and alkylpyridines. This is the first work dealing with GC-MS analysis of the rainwater in Moscow (Russia).

Association of Prenatal Phthalate Exposure With Language Development in Early Childhood

IMPORTANCE

Prenatal exposure to phthalates has been associated with neurodevelopmental outcomes, but little is known about the association with language development.

OBJECTIVE

To examine the association of prenatal phthalate exposure with language development in children in 2 population-based pregnancy cohort studies.

DESIGN, SETTING, AND PARTICIPANTS

Data for this study were obtained from the Swedish Environmental Longitudinal Mother and Child, Asthma and Allergy (SELMA) study conducted in prenatal clinics throughout Värmland county in Sweden and The Infant Development and the Environment Study (TIDES) conducted in 4 academic centers in the United States. Participants recruited into both studies were women in their first trimester of pregnancy who had literacy in Swedish (SELMA) or English or Spanish (TIDES). This study included mothers and their children from both the SELMA study (n = 963) and TIDES (n = 370) who had complete data on prenatal urinary phthalate metabolite levels, language delay, and modeled covariables. For SELMA, the data were collected from November 1, 2007, to June 30, 2013, and data analysis was conducted from November 1, 2016, to June 30, 2018. For TIDES, data collection began January 1, 2010, and ended March 29, 2016, and data analysis was performed from September 15, 2016, to June 30, 2018.

MAIN OUTCOMES AND MEASURES

Mothers completed a language development questionnaire that asked the number of words their children could understand or use at a median of 30 months of age (SELMA) and 37 months of age (TIDES). The responses were categorized as fewer than 25, 25 to 50, and more than 50 words, with 50 words or fewer classified as language delay.

RESULTS

In the SELMA study, 963 mothers, 455 (47.2%) girls, and 508 (52.8%) boys were included. In TIDES, 370 mothers, 185 (50.0%) girls, and 185 (50.0%) boys were included in this analysis. The prevalence of language delay was 10.0% in both SELMA (96 reported) and TIDES (37 reported), with higher rates of delay in boys than girls (SELMA: 69 [13.5%] vs 27 [6.0%]; TIDES: 23 [12.4%] vs 14 [7.6%]). In crude analyses, the metabolite levels of dibutyl phthalate and butyl benzyl phthalate were statistically significantly associated with language delay in both cohorts. In adjusted analyses, a doubling of prenatal exposure of dibutyl phthalate and butyl benzyl phthalate metabolites increased the odds ratio (OR) for language delay by approximately 25% to 40%, with statistically significant results in the SELMA study (dibutyl phthalate OR, 1.29 [95% CI, 1.03-1.63; P = .03]; butyl benzyl phthalate OR, 1.26 [95% CI, 1.07-1.49; P = .003]). A doubling of prenatal monoethyl phthalate exposure was associated with an approximately 15% increase in the OR for language delay in the SELMA study (OR, 1.14; 95% CI, 1.00-1.31; P = .05), but no such association was found in TIDES (OR, 0.98; 95% CI, 0.79-1.23).

CONCLUSIONS AND RELEVANCE

In findings from this study, prenatal exposure to dibutyl phthalate and butyl benzyl phthalate was statistically significantly associated with language delay in children in both the SELMA study and TIDES. These findings, along with the prevalence of prenatal exposure to phthalates, the importance of language development, and the inconsistent results from a 2017 Danish study, suggest that the association of phthalates with language delay may warrant further examination.

Endocrine Disruptors and Autism Spectrum Disorder in Pregnancy: A Review and Evaluation of the Quality of the Epidemiological Evidence

Exposure to environmental contaminants during pregnancy has been linked to adverse health outcomes later in life. Notable among these pollutants are the endocrine disruptors chemicals (EDCs), which are ubiquitously present in the environment and they have been measured and quantified in the fetus. In this systematic review, our objective was to summarize the epidemiological research on the potential association between prenatal exposure to EDCs and Autism Spectrum Disorder (ASD) published from 2005 to 2016. The Navigation Guide Systematic Review Methodology was applied. A total of 17 studies met the inclusion criteria for this review, including: five cohorts and 12 case-control. According to the definitions specified in the Navigation Guide, we rated the quality of evidence for a relationship between prenatal exposure to EDCs and ASD as "moderate". Although the studies generally showed a positive association between EDCs and ASD, after considering the strengths and limitations, we concluded that the overall strength of evidence supporting an association between prenatal exposure to EDCs and later ASD in humans remains "limited" and inconclusive. Further well-conducted prospective studies are warranted to clarify the role of EDCs on ASD development.

Bisphenol A (BPA) and bisphenol S (BPS) alter the promoter activity of the ABCB1 gene encoding P-glycoprotein in the human placenta in a haplotype-dependent manner

Exposure to bisphenols (BPA and BPS) during pregnancy can significantly affect fetal development and increase risk of adverse health consequences, however the underlying mechanisms are not fully elucidated. In human placenta, the efflux transporter P-glycoprotein (P-gp), encoded by the ABCB1 gene, extrudes its substrates from the trophoblasts back into the maternal circulation. Alterations in levels of placental P-gp could therefore significantly affect fetal exposure to xenobiotics that are P-gp substrates. The ABCB1 promoter contains many single nucleotide polymorphisms (SNPs). In the genome, SNPs are not arrayed as independent variants but as combinations forming defined haplotypes. Recently, we determined the haplotype sequences encompassing the ABCB1 promoter SNPs and found that promoter haplotypes differentially affect ABCB1 promoter activity. Here we investigate the effect of BPA and BPS on ABCB1 promoter activity by testing the hypothesis that BPA and BPS exposure affect ABCB1 promoter activity in a haplotype-dependent manner. Our data indicate that acute exposure to 50 nM BPA induced a significant haplotype-dependent increase in ABCB1 promoter activity (P < .05). However, acute exposure to 0.5 nM BPS induced a significant decrease (P < .05) in promoter activity that was haplotype-dependent. Chronic exposure to BPA and BPS individually (5 nM and 0.3 nM, respectively) or as a mixture (5 nM BPA:1.5 nM BPS) induced significant haplotype-dependent increases (P < .01) in ABCB1 promoter activity. Our data indicate that BPA and BPS significantly alter ABCB1 promoter activity in a haplotype- and exposure type- dependent manners. Such alteration could significantly impact placental P-gp levels and alter fetal exposure to many therapeutic and environmental xenobiotics.

Emerging contaminants in Brazilian rivers: Occurrence and effects on gene expression in zebrafish (Danio rerio) embryos

Emerging contaminants (ECs) are synthetic or naturally occurring chemicals that are not commonly monitored despite having the potential of entering the environment and causing adverse ecological and/or human health effects. This study aimed to determine whether ECs are present in the surface waters of two rivers in Mato Grosso do Sul State, Brazil, and evaluate the effects of ECs mixtures at environmentally relevant concentrations on zebrafish (Danio rerio) gene expression. ECs concentrations were determined using solid-phase extraction and liquid chromatography-mass spectrometry. The ECs most frequently detected were caffeine, imidacloprid, 2-hydroxy atrazine, tebuthiuron, atrazine, and bisphenol A. We used these data to reconstruct ECs mixtures reflecting environmental concentrations, codenamed T1, T2, and T3. No effects were observed, so the concentrations were increased. After a preliminary evaluation of the No Observed Effect Concentration for each mixture, we analyzed changes in the expression of zebrafish target genes (cyp1a, hsp70, cat, sod1, tsh, cyp19a1a, cyp19a1b, cyp26b1, casp8, sox2, cyb561d2, and thrb). cat was overrepresented in T1 and underrepresented in the other treatments. All of the mixtures induced the expression of cyp19a1b, which is a marker for (xeno-)estrogen exposure, and two of them increased the expression of cyp1a, which is used to indicate the presence of dioxin-like compounds. The rivers studied had low EC concentrations, and there was no indication of any harmful effects on the zebrafish. However, intensive agricultural activity may result in unsuspected peaks of EC pollution, and subsequent negative effects on living organisms.

Prenatal exposure to bisphenol A and phthalates and behavioral problems in children at preschool age: the Hokkaido Study on Environment and Children's Health

Background

Studies reported adverse behavioral development including internalizing and externalizing problems in association with prenatal exposure to bisphenol A (BPA) and phthalates; however, findings were not sufficient due to using different assessment tools and child ages among studies. This study aimed to examine associations between maternal serum levels of BPA and phthalate metabolites and behavioral problems at preschool age.

Methods

The Strengths and Difficulties Questionnaire (SDQ) was used to assess behavioral problems at 5 years of age. BPA and phthalate metabolite levels in the first trimester maternal serum was determined by LC-MS/MS for 458 children. Variables used for adjustment were parental ages, maternal cotinine levels, family income during pregnancy, child sex, birth order, and age at SDQ completed.

Results

The median concentrations of BPA, MnBP, MiBP, MEHP, and MECPP, primary and secondary metabolites of phthalates, were 0.062, 26.0, 7.0, 1.40, and 0.20 ng/ml, respectively. MECPP level was associated with increase conduct problem risk (OR = 2.78, 95% CI 1.36–5.68) overall and the association remained after child sex stratification, and odds ratios were increased with wider confidence interval (OR = 2.85, 95% CI 1.07–7.57 for boys, OR = 4.04, 95% CI 1.31–12.5 for girls, respectively). BPA, ∑DBP_m (MnBP + MiBP), and ∑DEHP_m (MEHP+MECPP) levels were not associated with any of the child behavioral problems.

Conclusions

Our analyses found no significant association between BPA or summation of phthalate metabolite levels and any of the behavioral problems at 5 years of age but suggested possible association between MECPP levels and increased risk of conduct problems.

Electronic supplementary material

The online version of this article (10.1186/s12199-018-0732-1) contains supplementary material, which is available to authorized users.

Atypical fetal development: Fetal alcohol syndrome, nutritional deprivation, teratogens, and risk for neurodevelopmental disorders and psychopathology

Accumulating evidence indicates that the fetal environment plays an important role in brain development and sets the brain on a trajectory across the life span. An abnormal fetal environment results when factors that should be present during a critical period of development are absent or when factors that should not be in the developing brain are present. While these factors may acutely disrupt brain function, the real cost to society resides in the long-term effects, which include important mental health issues. We review the effects of three factors, fetal alcohol exposure, teratogen exposure, and nutrient deficiencies, on the developing brain and the consequent risk for developmental psychopathology. Each is reviewed with respect to the evidence found in epidemiological and clinical studies in humans as well as preclinical molecular and cellular studies that explicate mechanisms of action.

Hypothalamic transcriptomic alterations in male and female California mice (Peromyscus californicus) developmentally exposed to bisphenol A or ethinyl estradiol

Bisphenol A (BPA) is an endocrine‐disrupting chemical (EDC) prevalent in many household items. Rodent models and human epidemiological studies have linked this chemical to neurobehavior impairments. In California mice, developmental exposure to BPA results in sociosexual disorders at adulthood, including communication and biparental care deficits, behaviors that are primarily regulated by the hypothalamus. Thus, we sought to examine the transcriptomic profile in this brain region of juvenile male and female California mice offspring exposed from periconception through lactation to BPA or ethinyl estradiol (EE, estrogen present in birth control pills and considered a positive estrogen control for BPA studies). Two weeks prior to breeding, P₀ females were fed a control diet, or this diet supplemented with 50 mg BPA/kg feed weight or 0.1 ppb EE, and continued on the diets through lactation. At weaning, brains from male and female offspring were collected, hypothalamic RNA isolated, and RNA‐seq analysis performed. Results indicate that BPA and EE groups clustered separately from controls with BPA and EE exposure leading to unique set of signature gene profiles. Kcnd3 was downregulated in the hypothalamus of BPA‐ and EE‐exposed females, whereas Tbl2, Topors, Kif3a, and Phactr2 were upregulated in these groups. Comparison of transcripts differentially expressed in BPA and EE groups revealed significant enrichment of gene ontology terms associated with microtubule‐based processes. Current results show that perinatal exposure to BPA or EE can result in several transcriptomic alterations, including those associated with microtubule functions, in the hypothalamus of California mice. It remains to be determined whether these genes mediate BPA‐induced behavioral disruptions.

Association between maternal exposure to major phthalates, heavy metals, and persistent organic pollutants, and the neurodevelopmental performances of their children at 1 to 2years of age- CHECK cohort study

Exposure of the developing fetus and infants to toxic substances can cause serious lifelong health consequences. Several chemicals have been associated with adverse neurodevelopmental disorders in the early life stages of humans. However, most epidemiological studies have focused on a limited number of chemicals, and hence may exclude important chemicals from consideration or result in conclusions built on associations by chance. In the present study, we investigated the chemical exposure profile of the women, and associated these with the early neurodevelopmental performance of their offspring at 13-24months of age. The chemicals assessed include four phthalates, bisphenol A, three heavy metals, 19 polychlorinated biphenyls (PCBs), 19 organochlorine pesticides, and 19 polybrominated diphenyl ethers, which were measured from urine, whole blood, serum, and/or breastmilk of the pregnant or lactating women. For neurodevelopmental performance, the Bayley Scales of Infant Development-II (BSID-II), Social Maturity Scale (SMS), and Child Behavior Checklist (CBCL) were measured from a total of 140 toddlers. Among the measured chemicals, monoethyl phthalate (MEP) in maternal urine was significantly associated with early mental, psychomotor, and social development. In addition, breast milk di-ethylhexyl phthalate (DEHP) metabolite and blood lead concentrations were inversely associated with mental and psychomotor development indices, respectively. Maternal blood PCB153, heavy metals, and urinary MEP levels were also higher among the children with behavioral problems, as indicated by the CBCL range. Taken together, maternal exposure to several EDCs such as PCBs and DEHP was associated with adverse neurodevelopmental performances among the children aged 1-2years. Confirmation of these association in larger populations, as well as longer-term consequences of such exposure warrant further investigation.

Prenatal Phthalates, Maternal Thyroid Function, and Risk of Attention-Deficit Hyperactivity Disorder in the Norwegian Mother and Child Cohort

BACKGROUND

There is growing concern that phthalate exposures may have an impact on child neurodevelopment. Prenatal exposure to phthalates has been linked with externalizing behaviors and executive functioning defects suggestive of an attention-deficit hyperactivity disorder (ADHD) phenotype.

OBJECTIVES

We undertook an investigation into whether prenatal exposure to phthalates was associated with clinically confirmed ADHD in a population-based nested case-control study of the Norwegian Mother and Child Cohort (MoBa) between the years 2003 and 2008.

METHODS

Phthalate metabolites were measured in maternal urine collected at midpregnancy. Cases of ADHD (n=297) were obtained through linkage between MoBa and the Norwegian National Patient Registry. A random sample of controls (n=553) from the MoBa population was obtained.

RESULTS

In multivariable adjusted coexposure models, the sum of di-2-ethylhexyl phthalate metabolites (∑DEHP) was associated with a monotonically increasing risk of ADHD. Children of mothers in the highest quintile of ∑DEHP had almost three times the odds of an ADHD diagnosis as those in the lowest [OR=2.99 (95% CI: 1.47, 5.49)]. When ∑DEHP was modeled as a log-linear (natural log) term, for each log-unit increase in exposure, the odds of ADHD increased by 47% [OR=1.47 (95% CI: 1.09, 1.94)]. We detected no significant modification by sex or mediation by prenatal maternal thyroid function or by preterm delivery.

CONCLUSIONS

In this population-based case-control study of clinical ADHD, maternal urinary concentrations of DEHP were monotonically associated with increased risk of ADHD. Additional research is needed to evaluate potential mechanisms linking phthalates to ADHD. https://doi.org/10.1289/EHP2358.

Migration modelling of phthalate from non-alcoholic beer bottles by adaptive neuro-fuzzy inference system

BACKGROUND

There are limitations to the basic knowledge regarding various ways by which packaging components migrate into food as well as ways by which various conditions, elements and molecules related to this phenomenon are analysed. This research aimed to model phthalate migration from polyethylene terephthalate bottles containing non-alcoholic beer by performing adaptive neuro-fuzzy inference system (ANFIS) analysis.

RESULTS

The data showed that storage temperature, contact surface and storage period correlates with the rate of migration. Migration of phthalate increases with storage duration gradually and reduces under different temperatures and contact surface. Moreover, increased temperature and storage duration resulted in an increase in migration level ranging from 0.6 μg L^-1 to 2.9 μg L^-1 . In summary, the present study used an ANFIS architecture which consists of three inputs (temperature, surface and storage period), Gauss-bell membership functions for each input variable and one output layer, which represent the migration level. The validation and training models showed an excellent match between the experimental and predicted values of ANFIS.

CONCLUSION

Analysis of the model showed that ANFIS is a powerful tool for predicting phthalate migration from bottles containing non-alcoholic beer. © 2017 Society of Chemical Industry.

Thyroid-disrupting chemicals and brain development: an update

This review covers recent findings on the main categories of thyroid hormone-disrupting chemicals and their effects on brain development. We draw mostly on epidemiological and experimental data published in the last decade. For each chemical class considered, we deal with not only the thyroid hormone-disrupting effects but also briefly mention the main mechanisms by which the same chemicals could modify estrogen and/or androgen signalling, thereby exacerbating adverse effects on endocrine-dependent developmental programmes. Further, we emphasize recent data showing how maternal thyroid hormone signalling during early pregnancy affects not only offspring IQ, but also neurodevelopmental disease risk. These recent findings add to established knowledge on the crucial importance of iodine and thyroid hormone for optimal brain development. We propose that prenatal exposure to mixtures of thyroid hormone-disrupting chemicals provides a plausible biological mechanism contributing to current increases in the incidence of neurodevelopmental disease and IQ loss.

Understanding environmental contributions to autism: Causal concepts and the state of science

The complexity of neurodevelopment, the rapidity of early neurogenesis, and over 100 years of research identifying environmental influences on neurodevelopment serve as backdrop to understanding factors that influence risk and severity of autism spectrum disorder (ASD). This Keynote Lecture, delivered at the May 2016 annual meeting of the International Society for Autism Research, describes concepts of causation, outlines the trajectory of research on nongenetic factors beginning in the 1960s, and briefly reviews the current state of this science. Causal concepts are introduced, including root causes; pitfalls in interpreting time trends as clues to etiologic factors; susceptible time windows for exposure; and implications of a multi-factorial model of ASD. An historical background presents early research into the origins of ASD. The epidemiologic literature from the last fifteen years is briefly but critically reviewed for potential roles of, for example, air pollution, pesticides, plastics, prenatal vitamins, lifestyle and family factors, and maternal obstetric and metabolic conditions during her pregnancy. Three examples from the case-control CHildhood Autism Risks from Genes and the Environment Study are probed to illustrate methodological approaches to central challenges in observational studies: capturing environmental exposure; causal inference when a randomized controlled clinical trial is either unethical or infeasible; and the integration of genetic, epigenetic, and environmental influences on development. We conclude with reflections on future directions, including exposomics, new technologies, the microbiome, gene-by-environment interaction in the era of -omics, and epigenetics as the interface of those two. As the environment is malleable, this research advances the goal of a productive and fulfilling life for all children, teen-agers and adults. Autism Res 2018, 11: 554-586. © 2018 International Society for Autism Research, Wiley Periodicals, Inc.

LAY SUMMARY

This Keynote Lecture, delivered at the 2016 meeting of the International Society for Autism Research, discusses evidence from human epidemiologic studies of prenatal factors contributing to autism, such as pesticides, maternal nutrition and her health. There is no single cause for autism. Examples highlight the features of a high-quality epidemiology study, and what comprises a compelling case for causation. Emergent research directions hold promise for identifying potential interventions to reduce disabilities, enhance giftedness, and improve lives of those with ASD.

Phthalate exposure in Thai children and adolescents

Background

Phthalates are found in products made of plastic. Because of concerns regarding the hazards of phthalate exposure, including endocrine disruption, many countries have regulations to restrict their use in products used by children. However, in Thailand, no such restrictions exist, and data relating to phthalate exposure are scarce.

Objectives

To determine the level of exposure of Thai children and adolescents to phthalates, and study its associations with sociodemographic data and the exposure to potential sources of phthalates.

Methods

Healthy children aged 2–18 y were enrolled into the present cross-sectional study between January 2016 and December 2016 inclusive. Their anthropometric indices and Tanner staging were determined. Urinary concentrations of the phthalate metabolites, monomethyl phthalate (MMP) and mono-n-butyl phthalate (MBP), were determined in spot samples by high-performance liquid chromatography to estimate the level of phthalate exposure. Associations between sociodemographic data, exposure to potential sources of phthalates, and phthalate metabolite concentrations were analyzed.

Results

We included 103 boys and 118 girls with a mean age of 9.4 ± 3.64 (range 2.8–17.1) y and detected MMP in 28.5% and MBP in 88.6%. The geometric means (interquartile range) of urinary MMP and MBP were 3400 (2489, 4642) and 214.4 (164, 279) μg/g creatinine (Cr), respectively. Significant associations were found between exposure to floor cleaning products and Cr-adjusted urinary MMP level (P < 0.05), and paint and Cr-adjusted urinary MMP and MBP levels (P < 0.05). Prepuberty was significantly associated with urinary Cr-adjusted MMP level.

Conclusion

Urinary phthalate metabolite levels were high in a proportion of Thai children and adolescents. Exposure to floor cleaning products and paint is associated with phthalate exposure, and advanced Tanner stage is negatively associated with urinary Cr-adjusted MBP.

Persistent plasticizers and bisphenol in the cheese of Tunisian markets induced biochemical and histopathological alterations in male BALB/c mice

Clinical evidences, experimental models, and epidemiology of many studies suggest that phthalate-based plasticizers, aliphatic ester, and bisphenol A (BPA) have major risks for humans by targeting different organs and body systems. The current study has been designed firstly to analyze three categories of cheese with and without their exposure to the sun and packed in packages with an inner surface plastic-covered film in order to identify the dibutyl phthalate (DBP); benzyl butyl phthalate (BBP); bis(2-ethylhexyl) phthalate (DEHP); diisodecyl phthalate (DiDP); diisononyl phthalate (DiNP); and 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH) by GC-MS/MS, except for the bisphenol A, which is by UPLC-MS/MS, and secondly to assess the toxicity of the identified chemical molecules and cheese samples on the liver and kidney of mice. Our results showed that the cheese contains high quantities of DBP and DEHP with the concentrations up to 0.46 and 2.339 mg/kg, respectively. Other types of cheese, such as rolled and triangular cheeses, contain little quantities of the all substances at concentrations below the standard limits. In vivo, the obtained data clearly demonstrated that the acute administration of DBP, DEHP, and the tested cheese significantly induced liver and kidney injuries in mice manifested by a rise in plasma alanine aminotransferase, aspartate aminotransferase, blood urea nitrogen, lactate dehydrogenase, urea, creatinine, and uric acid when compared with control animals. In addition, the histopathological study confirmed the perturbation of biochemical parameters and showed that the hepatic and renal structures were altered. Indeed, the hepatotoxic and nephrotoxic effects are more pronounced when cheese was exposed to the sun.

Effects of Perinatal Exposure to Phthalates and a High-Fat Diet on Maternal Behavior and Pup Development and Social Play

Humans are ubiquitously exposed to many phthalates, a class of endocrine-disrupting chemicals commonly used in many consumer goods, and diet, especially fatty food, is presumed to be a major source of exposure. Here, we use a rat model of human prenatal exposure to investigate the potential interactive effects of an environmentally relevant mixture of phthalates and a maternal high-fat diet (HFD). From gestation through postnatal day (P)10, dams consumed the mixture of phthalates (0, 200, or 1000 μg/kg/d) and were fed a control diet or HFD. In males, perinatal exposure to the mixture of phthalates decreased prepubertal body weight and, in a dose-specific manner, periadolescent social play behavior. A dose-specific effect from phthalates with HFD was also seen in increased time alone in females during social play. HFD resulted in dams consuming more calories, having greater gestational weight gain, and licking and nursing their pups more, such that an early postnatal HFD generally increased pup body weight. There also was a tendency for increased oxidative stress markers at P10 within the medial prefrontal cortex of males exposed to the relatively high dose of phthalates and HFD. Effects on gene expression were inconsistent at P10 and P90 in both the medial prefrontal cortex and hypothalamus. Overall, this study demonstrates that phthalates and a maternal HFD only rarely interacted, except in oxidative stress markers in males. Additionally, perinatal exposure to an environmentally relevant mixture of phthalates can have a modest, but lasting, impact on social behaviors in both males and females.

EDC IMPACT: Molecular effects of developmental FM 550 exposure in Wistar rat placenta and fetal forebrain

Firemaster 550 (FM 550) is a flame retardant (FR) mixture that has become one of the most commonly used FRs in foam-based furniture and baby products. Human exposure to this commercial mixture, composed of brominated and organophosphate components, is widespread. We have repeatedly shown that developmental exposure can lead to sex-specific behavioral effects in rats. Accruing evidence of endocrine disruption and potential neurotoxicity has raised concerns regarding the neurodevelopmental effects of FM 550 exposure, but the specific mechanisms of action remains unclear. Additionally, we observed significant, and in some cases sex-specific, accumulation of FM 550 in placental tissue following gestational exposure. Because the placenta is an important source of hormones and neurotransmitters for the developing brain, it may be a critical target of toxicity to consider in the context of developmental neurotoxicity. Using a mixture of targeted and exploratory approaches, the goal of the present study was to identify possible mechanisms of action in the developing forebrain and placenta. Wistar rat dams were orally exposed to FM 550 (0, 300 or 1000 µg/day) for 10 days during gestation and placenta and fetal forebrain tissue collected for analysis. In placenta, evidence of endocrine, inflammatory and neurotransmitter signaling pathway disruption was identified. Notably, 5-HT turnover was reduced in placental tissue and fetal forebrains indicating that 5-HT signaling between the placenta and the embryonic brain may be disrupted. These findings demonstrate that environmental contaminants, like FM 550, have the potential to impact the developing brain by disrupting normal placental functions.

Impact of Endocrine Disruptors on the Thyroid Hormone System

The thyroid hormone (TH) system plays a central role in central physiological processes of many species, including mammals and humans, ranging from growth and cell differentiation, energy metabolism, thermoregulation and phasing of hibernation or annual movements of migratory species, metamorphosis from larvae to adult forms, brain development, reproduction, or the cardiovascular system. Several chemicals are known to be TH-disrupting compounds (THDCs) and have been shown to interact with virtually all elements of TH homeostasis such as feedback mechanisms with the hypothalamus-pituitary axis, TH synthesis, TH storage and release from the thyroid gland, transport protein binding and TH distribution in tissues and organs, cellular TH uptake, intracellular TH metabolism, and TH receptor binding. Therefore, chemicals interfering with the TH homeostasis have the potential to interact with many of these important processes, and especially early-life stage exposure results in permanent alterations of tissue organization and homeostatic regulation of adaptive processes. This is not only of theoretical importance as the reported plasma concentrations of THDCs in human plasma fall well within the range of reported in vitro effect concentrations, and this is of even higher importance as the developing fetus and young children are in a sensitive developmental stage.

Bisphenol A Causes Liver Damage and Selectively Alters the Neurochemical Coding of Intrahepatic Parasympathetic Nerves in Juvenile Porcine Models under Physiological Conditions

Bisphenol A (BPA) is an extremely common polymer that is used in typical everyday products throughout the world, especially in food and beverage containers. Within the last ten years, it has been found that the BPA monomer tends to leach into foodstuffs, and nanogram concentrations of it may cause a variety of deleterious health effects. These health problems are very evident in developing children and in young adults. The aim of this study was to expose developing pigs to dietary BPA at both legally acceptable and ten-fold higher levels. Livers that had been exposed to BPA showed vacuolar degeneration, sinusoidal dilatation, vascular congestion and glycogen depletion that increased with exposure levels. Furthermore, the livers of these models were then examined for irregularities and double-labeled immunofluorescence was used to check the innervated hepatic samples for varying neuronal expression of selected neuronal markers in the parasympathetic nervous system (PSNS). It was found that both the PSNS and all of the neuronal markers showed increased expression, with some of them being significant even at recommended safe exposure levels. The implications are quite serious since these effects have been observed at recommended safe levels with expression increasing in-line with exposure levels. The increased neuronal markers studied here have been previously correlated with behavioral/psychological disorders of children and young adults, as well as with childhood obesity and diabetes. However, further research must be performed in order to develop a mechanism for the above-mentioned correlations.

Environmental Exposure to Dioxins, Dibenzofurans, Bisphenol A, and Phthalates in Children with and without Autism Spectrum Disorder Living near the Gulf of Mexico

Environmental exposure to organic endocrine disrupting chemicals, including dioxins, dibenzofurans, bisphenol A (BPA), and phthalates has been associated with neurodevelopmental disorders, including autism spectrum disorder (ASD). We conducted a pilot monitoring study of 30 ASD cases and 10 typically developing (TD) controls ages 2-8 years from communities along the Gulf of Mexico near Alabama, which houses 14 Superfund sites, to assess the concentrations of dioxins and dibenzofurans in serum, and BPA and phthalate ester metabolites in urine. Based on General Linear Models, the lipid- or creatinine-adjusted geometric mean concentrations of the aforementioned chemicals did not differ between the ASD case and TD control groups (all p ≥ 0.27). We compared our findings to the adjusted means as reported by the National Health and Nutrition Examination Survey, survey years 2011-2012, and found that TD controls in our study had lower BPA (59%) and MEHHP (26%) concentrations, higher MBP (50%) concentration, and comparable (<20% difference) MEP, MBZP, MEOHP, and MCPP concentrations. We also conducted a preliminary investigation of dietary exposures and found that the consumption of certain types of fish may be associated with higher OCDD concentrations, and the consumption of soft drinks and juices may be associated with lower BPA and MEOHP concentrations, respectively.

Phthalates impact human health: Epidemiological evidences and plausible mechanism of action

Disregarding the rising alarm on the hazardous nature of various phthalates and their metabolites, ruthless usage of phthalates as plasticizer in plastics and as additives in innumerable consumer products continues due low their cost, attractive properties, and lack of suitable alternatives. Globally, in silico computational, in vitro mechanistic, in vivo preclinical and limited clinical or epidemiological human studies showed that over a dozen phthalates and their metabolites ingested passively by man from the general environment, foods, drinks, breathing air, and routine household products cause various dysfunctions. Thus, this review addresses the health hazards posed by phthalates on children and adolescents, epigenetic modulation, reproductive toxicity in women and men; insulin resistance and type II diabetes; overweight and obesity, skeletal anomalies, allergy and asthma, cancer, etc., coupled with the description of major phthalates and their general uses, phthalate exposure routes, biomonitoring and risk assessment, special account on endocrine disruption; and finally, a plausible molecular cross-talk with a unique mechanism of action. This clinically focused comprehensive review on the hazards of phthalates would benefit the general population, academia, scientists, clinicians, environmentalists, and law or policy makers to decide upon whether usage of phthalates to be continued swiftly without sufficient deceleration or regulated by law or to be phased out from earth forever.