Are endocrine disrupting compounds environmental risk factors for autism spectrum disorder?

Exploring autism spectrum disorder (ASD) and attention deficit disorder (ADD/ADHD) in children exposed to polybrominated biphenyl

Background

Although the causes of attention-deficit/hyperactivity disorder (ADHD) and autism have not been identified, exposure to endocrine-disrupting chemicals, such as polybrominated biphenyl (PBB), during fetal development and early life has been suspected to impact neurological development. This study aims to investigate the association between prenatal and early life exposure to PBB and the development of ADHD and autism later in life.

Methods

Data from the Michigan PBB Registry, a cohort of Michigan residents who had been exposed to PBB in a mass contamination event in 1973, was leveraged for this nested case-control analysis among two distinct samples: (1) Those who self-reported ADHD or autism diagnosis, and (2) mothers who reported their child's ADHD or autism diagnosis. PBB exposure was measured in participants of the PBB Registry, and the mother's PBB level was used in mother-reported analyses. Cases were matched with controls by sex and year of birth. Conditional logistic regression models were used to estimate the association between PBB level and case status.

Results

PBB levels were higher among those who were exposed in early life compared with those exposed in utero (geometric mean: 0.300 ng/ml vs. 0.016 ng/ml). Among women in this cohort, a higher than expected proportion of self-reported ADHD diagnosis (11.11%), compared with population estimates. PBB was not associated with ADHD or autism in either self-reported or mother-reported analyses.

Conclusions

This study adds to the sparse literature about prenatal and early life exposure to PBB-153 and ADHD and autism. Future studies should examine potential effect modification by sex.

Linking Environmental Chemicals to Neuroinflammation and Autism Spectrum Disorder: Mechanisms and Implications for Prevention

This article explores the potential link between endocrine-disrupting chemicals (EDCs), neuroinflammation, and the development of autism spectrum disorder (ASD). Neuroinflammation refers to the immune system's response to injury, infection, or disease in the central nervous system. Studies have shown that exposure to EDCs, such as bisphenol A and phthalates, can disrupt normal immune function in the brain, leading to chronic or excessive neuroinflammation. This disruption of immune function can contribute to developing neurological disorders, including ASD. Furthermore, EDCs may activate microglia, increasing pro-inflammatory cytokine production and astroglia-mediated oxidative stress, exacerbating neuroinflammation. EDCs may also modulate the epigenetic profile of cells by methyltransferase expression, thereby affecting neurodevelopment. This article also highlights the importance of reducing exposure to EDCs and advocating for policies and regulations restricting their use. Further research is needed to understand better the mechanisms underlying the link between EDCs, neuroinflammation, and ASD and to develop new treatments for ASD.

Uncovering the common factors of chemical exposure and behavior: Evaluating behavioral effects across a testing battery using factor analysis

Although specific environmental chemical exposures, including flame retardants, are known risk factors for neurodevelopmental disorders (NDDs), direct experimental evidence linking specific chemicals to NDDs is limited. Studies focusing on the mechanisms by which the social processing systems are vulnerable to chemical exposure are underrepresented in the literature, even though social impairments are defining characteristics of many NDDs. We have repeatedly demonstrated that exposure to Firemaster 550 (FM 550), a prevalent flame retardant mixture used in foam-based furniture and infant products, can adversely impact a variety of behavioral endpoints. Our recent work in prairie voles (Microtus ochrogaster), a prosocial animal model, demonstrated that perinatal exposure to FM 550 sex specifically impacts socioemotional behavior. Here, we utilized a factor analysis approach on a battery of behavioral data from our prior study to extract underlying factors that potentially explain patterns within the FM 550 behavior data. This approach identified which aspects of the behavioral battery are most robust and informative, an outcome critical for future study designs. Pearson's correlation identified behavioral endpoints associated with distance and stranger interactions that were highly correlated across 5 behavioral tests. Using these behavioral endpoints, exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) extracted 2 factors that could explain the data: Activity (distance traveled endpoints) and Sociability (time spent with a novel conspecific). Exposure to FM 550 significantly decreased Activity and decreased Sociability. This factor analysis approach to behavioral data offers the advantages of modeling numerous measured variables and simplifying the data set by presenting the data in terms of common, overarching factors in terms of behavioral function.

Bisphenol AF Induces Prostatic Dorsal Lobe Hyperplasia in Rats through Activation of the NF-κB Signaling Pathway

Bisphenol AF (BPAF) represents a common environmental estrogenic compound renowned for its capacity to induce endocrine disruptions. Notably, BPAF exhibits an enhanced binding affinity to estrogen receptors, which may have more potent estrogenic activity compared with its precursor bisphenol A (BPA). Notwithstanding, the existing studies on BPAF-induced prostate toxicity remain limited, with related toxicological research residing in the preliminary stage. Our previous studies have confirmed the role of BPAF in the induction of ventral prostatic hyperplasia, but its role in the dorsal lobe is not clear. In this study, BPAF (10, 90 μg/kg) and the inhibitor of nuclear transcription factor-κB (NF-κB), pyrrolidinedithiocarbamate (PDTC, 100 mg/kg), were administered intragastrically in rats for four weeks. Through comprehensive anatomical and pathological observations, as well as the assessment of PCNA over-expression, we asserted that BPAF at lower doses may foster dorsal prostatic hyperplasia in rats. The results of IHC and ELISA indicated that BPAF induced hyperplastic responses in the dorsal lobe of the prostate by interfering with a series of biomarkers in NF-κB signaling pathways, containing NF-κB p65, COX-2, TNF-α, and EGFR. These findings confirm the toxic effect of BPAF on prostate health and emphasize the potential corresponding mechanisms.

Exposure to nonylphenol in early life causes behavioural deficits related with autism spectrum disorders in rats

Early-life exposure to environmental endocrine disruptors (EDCs) is a potential risk factor for autism spectrum disorder (ASD). Exposure to nonylphenol (NP), a typical EDC, is known to cause some long-term behavioural abnormalities. Moreover, these abnormal behaviours are the most frequent psychiatric co-morbidities in ASD. However, the direct evidence for the link between NP exposure in early life and ASD-like behavioural phenotypes is still missing. In the present study, typical ASD-like behaviours induced by valproic acid treatment were considered as a positive behavioural control. We investigated impacts on social behaviours following early-life exposure to NP, and explored effects of this exposure on neuronal dendritic spines, mitochondria function, oxidative stress, and endoplasmic reticulum (ER) stress. Furthermore, primary cultured rat neurons were employed as in vitro model to evaluate changes in dendritic spine caused by exposure to NP, and oxidative stress and ER stress were specifically modulated to further explore their roles in these changes. Our results indicated rats exposed to NP in early life showed mild ASD-like behaviours. Moreover, we also found the activation of ER stress triggered by oxidative stress may contribute to dendritic spine decrease and synaptic dysfunction, which may underlie neurobehavioural abnormalities induced by early-life exposure to NP.

A pilot study of several environmental endocrine disrupting chemicals in children with autism spectrum disorder in south China

Autism spectrum disorders (ASD) is a group of heterogeneous neurodevelopmental disorders. Evidence has implied that environmental pollutants are important factors related to ASD. In this study, several environmental endocrine-disrupting chemicals, including parabens, benzophenone-type ultraviolet filters, hydroxyl polycyclic aromatic hydrocarbons, triclosan and tetrabromobisphenol A were analyzed in blood plasma in ASD children (n = 34) and the control children (n = 28). The results showed that parabens were the most concentrated chemicals (2.18 ng/mL, median value), followed by hydroxyl polycyclic aromatic hydrocarbons (0.73 ng/mL), benzophenone-type ultraviolet filters (0.14 ng/mL), triclosan (0.13 ng/mL) and tetrabromobisphenol A (0.03 ng/mL). ASD children accumulated significantly lower 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 4-hydroxybenzophenone and triclosan but higher 2-hydroxyphenanthrene and tetrabromobisphenol A than the control children (0.02/0.09 ng/mL of 2-hydroxy-4-methoxybenzophenone, p < 0.05; 0.04/0.07 ng/mL of 2,4-dihydroxybenzophenone, p < 0.05; 0.03/0.04 ng/mL of 4-hydroxybenzophenone, p < 0.05; 0.13/1.22 ng/mL of triclosan, p < 0.01; 0.03 ng/mL/not detected of 2-hydroxyphenanthrene, p < 0.05; 0.03/0.004 ng/mL of tetrabromobisphenol A, p < 0.05). Gender differences in certain environmental endocrine-disrupting chemicals were evident, and the differences were more inclined toward boys. Positive associations between 2-hydroxy-4-methoxybenzophenone and triclosan, and tetrabromobisphenol A and 2-hydroxyphenanthrene were found in ASD boys. Binary logistic regression analysis showed that the adjusted odds ratio value of 2-hydroxyphenanthrene in ASD boys was 11.0 (1.45-84.0, p < 0.05). This is the first pilot study on multiple environmental endocrine-disrupting chemicals in children with ASD in China.

Endocrine disrupting compounds in the baby's world - A harmful environment to the health of babies

Globally, there has been a significant increase in awareness of the adverse effects of chemicals with known or suspected endocrine-acting properties on human health. Human exposure to endocrine disrupting compounds (EDCs) mainly occurs by ingestion and to some extent by inhalation and dermal uptake. Although it is difficult to assess the full impact of human exposure to EDCs, it is well known that timing of exposure is of importance and therefore infants are more vulnerable to EDCs and are at greater risk compared to adults. In this regard, infant safety and assessment of associations between prenatal exposure to EDCs and growth during infancy and childhood has been received considerable attention in the last years. Hence, the purpose of this review is to provide a current update on the evidence from biomonitoring studies on the exposure of infants to EDCs and a comprehensive view of the uptake, the mechanisms of action and biotransformation in baby/human body. Analytical methods used and concentration levels of EDCs in different biological matrices (e.g., placenta, cord plasma, amniotic fluid, breast milk, urine, and blood of pregnant women) are also discussed. Finally, key issues and recommendations were provided to avoid hazardous exposure to these chemicals, taking into account family and lifestyle factors related to this exposure.

Co-exposure to toxic metals and phthalates in pregnant women and their children's mental health problems aged four years - Taiwan Maternal and Infant Cohort Study (TMICS)

BACKGROUND

Childhood and adolescent mental health problems may increase the global burden of disease. Neurotoxic metals are associated with inflammation and cytotoxicity in the brain. In addition, prenatal phthalate ester (PAE) exposure is associated with cognitive function deficits. However, the effect of co-exposure to toxic metals, PAEs, and their association with child behavior is less well studied. Hence, we aimed to investigate prenatal co-exposure to the metals and PAEs and the consequent behavioral outcomes in early childhood.

METHODS

We followed pregnant women and their newborns from the Taiwan Maternal and Infant Cohort Study between 2015 and 2017, with a focus on women from the central, southern, and eastern areas of Taiwan. We quantified maternal urinary concentrations of metals and metabolites of PAEs as surrogates of prenatal exposure. We recorded the Child Behavior Checklist scores according to caregiver reports at 4 years of age, and identified Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5)-oriented problems.

RESULTS

Ultimately, 408 children were included in the statistical analysis. Maternal urinary copper levels were significantly associated with depressive problems (odds ratio [OR] = 2.13) in children. Maternal urinary concentrations of mono-n-butyl phthalate (MnBP) and mono-isobutyl phthalate (MiBP) were also significantly associated with depressive symptoms (odds ratio [OR] = 1.51 and 1.53, respectively). Further analysis considering prenatal co-exposure to metals and PAEs showed that co-exposure to these materials was significantly associated with autism spectrum problems (OR = 3.11).

CONCLUSIONS

We observed that prenatal single exposure or co-exposure to metals and PAEs may play a role in some DSM-5-oriented problems in children at 4 years of age. Reduction of exposure to toxic metals and PAEs in pregnancy is suggested to prevent increased mental health problems in children.

Investigation of autism-related transcription factors underlying sex differences in the effects of bisphenol A on transcriptome profiles and synaptogenesis in the offspring hippocampus

BACKGROUND

Bisphenol A (BPA) has been linked to susceptibility to autism spectrum disorder (ASD). Our recent studies have shown that prenatal BPA exposure disrupted ASD-related gene expression in the hippocampus, neurological functions, and behaviors associated with ASD in a sex-specific pattern. However, the molecular mechanisms underlying the effects of BPA are still unclear.

METHODS

Transcriptome data mining and molecular docking analyses were performed to identify ASD-related transcription factors (TFs) and their target genes underlying the sex-specific effects of prenatal BPA exposure. Gene ontology analysis was conducted to predict biological functions associated with these genes. The expression levels of ASD-related TFs and targets in the hippocampus of rat pups prenatally exposed to BPA were measured using qRT-PCR analysis. The role of the androgen receptor (AR) in BPA-mediated regulation of ASD candidate genes was investigated using a human neuronal cell line stably transfected with AR-expression or control plasmid. Synaptogenesis, which is a function associated with genes transcriptionally regulated by ASD-related TFs, was assessed using primary hippocampal neurons isolated from male and female rat pups prenatally exposed to BPA.

RESULTS

We found that there was a sex difference in ASD-related TFs underlying the effects of prenatal BPA exposure on the transcriptome profiles of the offspring hippocampus. In addition to the known BPA targets AR and ESR1, BPA could directly interact with novel targets (i.e., KDM5B, SMAD4, and TCF7L2). The targets of these TFs were also associated with ASD. Prenatal BPA exposure disrupted the expression of ASD-related TFs and targets in the offspring hippocampus in a sex-dependent manner. Moreover, AR was involved in the BPA-mediated dysregulation of AUTS2, KMT2C, and SMARCC2. Prenatal BPA exposure altered synaptogenesis by increasing synaptic protein levels in males but not in females, but the number of excitatory synapses was increased in female primary neurons only.

CONCLUSIONS

Our findings suggest that AR and other ASD-related TFs are involved in sex differences in the effects of prenatal BPA exposure on transcriptome profiles and synaptogenesis in the offspring hippocampus. These TFs may play an essential role in an increased ASD susceptibility associated with endocrine-disrupting chemicals, particularly BPA, and the male bias of ASD.

Brief postnatal exposure to bisphenol A affects apoptosis and gene expression in the medial prefrontal cortex and social behavior in rats with sex specificity

Bisphenol A (BPA) is an endocrine disruptor found in polycarbonate plastics and exposure in humans is nearly ubiquitous and it has widespread effects on cognitive, emotional, and reproductive behaviors in both humans and animal models. In our laboratory we previously found that perinatal BPA exposure results in a higher number of neurons in the adult male rat prefrontal cortex (PFC) and less play in adolescents of both sexes. Here we examine changes in the rate of postnatal apoptosis in the rat prefrontal cortex and its timing with brief BPA exposure. Because an increased number of neurons in the PFC is a characteristic of a subtype of autism spectrum disorder, we tested social preference following brief BPA exposure and also expression of a small group of genes. Males and females were exposed to BPA from postnatal days (P) 6 through 8 or from P10 through 12. Both exposures significantly decreased indicators of cell death in the developing medial prefrontal cortex in male subjects only. Additionally, males exposed to BPA from P6 - 8 showed decreased social preference and decreased cortical expression of Shank3 and Homer1, two synaptic scaffolding genes that have been implicated in social deficits. There were no significant effects of BPA in the female subjects. These results draw attention to the negative consequences following brief exposure to BPA during early development.

Gene×environment interactions in autism spectrum disorders

There is credible evidence that environmental factors influence individual risk and/or severity of autism spectrum disorders (hereafter referred to as autism). While it is likely that environmental chemicals contribute to the etiology of autism via multiple mechanisms, identifying specific environmental factors that confer risk for autism and understanding how they contribute to the etiology of autism has been challenging, in part because the influence of environmental chemicals likely varies depending on the genetic substrate of the exposed individual. Current research efforts are focused on elucidating the mechanisms by which environmental chemicals interact with autism genetic susceptibilities to adversely impact neurodevelopment. The goal is to not only generate insights regarding the pathophysiology of autism, but also inform the development of screening platforms to identify specific environmental factors and gene×environment (G×E) interactions that modify autism risk. Data from such studies are needed to support development of intervention strategies for mitigating the burden of this neurodevelopmental condition on individuals, their families and society. In this review, we discuss environmental chemicals identified as putative autism risk factors and proposed mechanisms by which G×E interactions influence autism risk and/or severity using polychlorinated biphenyls (PCBs) as an example.

Early life exposure to triclosan from antimicrobial daily necessities may increase the potential risk of autism spectrum disorder: A multicenter study in China

BACKGROUND

Autism spectrum disorders (ASD) are a group of complex neurodevelopmental disorders with unclear etiologies. Our recent work indicated that maternal exposure to triclosan (TCS) significantly increased the autistic-like behavior in rats, possibly through disrupting neuronal retinoic acid signaling. Although environmental endocrine disruptors (EEDs) have been associated with autism in humans, the relationship between TCS, one of the EEDs found in antibacterial daily necessities, and autism has received little attention.

OBJECTIVE

The aims of this multicenter study were to evaluate TCS concentrations in typically developing (TD) children and ASD children, and to determine the relationship between TCS levels and the core symptoms of ASD children.

METHODS

A total of 1345 children with ASD and 1183 TD children were enrolled from 13 cities in China. Ages ranged between 2 and 7 years. A questionnaire was used to investigate the maternal use of antibacterial daily necessities (UADN) during pregnancy. The core symptoms of ASD were evaluated using the Autism Behavior Checklist (ABC), Childhood Autism Rating Scale (CARS), Social Response Scale (SRS), and the Children Neuropsychological and Behavior Scale-Revision 2016 (CNBS-R2016). The TCS concentration was measured using LC-MS/MS.

RESULTS

Maternal UADN during pregnancy may be an unrecognized potential environmental risk factor for ASD (OR=1.267, P = 0.023). Maternal UADN during pregnancy strongly correlated with TCS levels in the offspring (Adjusted β = 0.277, P < 0.001). TCS concentration was higher in ASD children (P = 0.005), and positively correlated with ABC (Sensory subscales: P = 0.03; Social self-help subscales: P = 0.011) and SRS scale scores (Social awareness subscales: P = 0.045; Social communication subscales: P = 0.001; Autism behavior mannerisms subscales: P = 0.006; SRS total score: P = 0.003) in ASD children. This association was more pronounced in boys than in girls.

CONCLUSION

To our knowledge, this is the first case-control study to examine the correlation between TCS and ASD. Our results suggest that maternal UADN during pregnancy may be a potential risk of ASD in offspring. Further detection of TCS levels showed that maternal UADN during pregnancy may be associated with excessive TCS exposure. In addition, the level of TCS in children with ASD is higher than TD children. The higher levels of TCS in children with ASD may be significantly associated with more pronounced core symptoms, and this association was more significant in male children with ASD.

Sex-specific Effects of Endocrine-disrupting Chemicals on Brain Monoamines and Cognitive Behavior

The period of brain sexual differentiation is characterized by the development of hormone-sensitive neural circuits that govern the subsequent presentation of sexually dimorphic behavior in adulthood. Perturbations of hormones by endocrine-disrupting chemicals (EDCs) during this developmental period interfere with an organism's endocrine function and can disrupt the normative organization of male- or female-typical neural circuitry. This is well characterized for reproductive and social behaviors and their underlying circuitry in the hypothalamus and other limbic regions of the brain; however, cognitive behaviors are also sexually dimorphic, with their underlying neural circuitry potentially vulnerable to EDC exposure during critical periods of brain development. This review provides recent evidence for sex-specific changes to the brain's monoaminergic systems (dopamine, serotonin, norepinephrine) after developmental EDC exposure and relates these outcomes to sex differences in cognition such as affective, attentional, and learning/memory behaviors.

Elevated exposures to persistent endocrine disrupting compounds impact the sperm methylome in regions associated with autism spectrum disorder

Environmental exposures to endocrine disrupting compounds (EDCs) such as the organochlorines have been linked with various diseases including neurodevelopmental disorders. Autism spectrum disorder (ASD) is a highly complex neurodevelopmental disorder that is considered strongly genetic in origin due to its high heritability. However, the rapidly rising prevalence of ASD suggests that environmental factors may also influence risk for ASD. In the present study, whole genome bisulfite sequencing was used to identify genome-wide differentially methylated regions (DMRs) in a total of 52 sperm samples from a cohort of men from the Faroe Islands (Denmark) who were equally divided into high and low exposure groups based on their serum levels of the long-lived organochlorine 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), a primary breakdown product of the now banned insecticide dichlorodiphenyltrichloroethane (DDT). Aside from being considered a genetic isolate, inhabitants of the Faroe Islands have a native diet that potentially exposes them to a wide range of seafood neurotoxicants in the form of persistent organic pollutants (POPs). The DMRs were mapped to the human genome using Bismark, a 3-letter aligner used for methyl-seq analyses. Gene ontology, functional, and pathway analyses of the DMR-associated genes showed significant enrichment for genes involved in neurological functions and neurodevelopmental processes frequently impacted by ASD. Notably, these genes also significantly overlap with autism risk genes as well as those previously identified in sperm from fathers of children with ASD in comparison to that of fathers of neurotypical children. These results collectively suggest a possible mechanism involving altered methylation of a significant number of neurologically relevant ASD risk genes for introducing epigenetic changes associated with environmental exposures into the sperm methylome. Such changes may provide the potential for transgenerational inheritance of ASD as well as other disorders.

Individual and Combined Effects of Paternal Deprivation and Developmental Exposure to Firemaster 550 on Socio-Emotional Behavior in Prairie Voles

The prevalence of neurodevelopmental disorders (NDDs) is rapidly rising, suggesting a confluence of environmental factors that are likely contributing, including developmental exposure to environmental contaminants. Unfortunately, chemical exposures and social stressors frequently occur simultaneously in many communities, yet very few studies have sought to establish the combined effects on neurodevelopment or behavior. Social deficits are common to many NDDs, and we and others have shown that exposure to the chemical flame retardant mixture, Firemaster 550 (FM 550), or paternal deprivation impairs social behavior and neural function. Here, we used a spontaneously prosocial animal model, the prairie vole (Microtus ochrogaster), to explore the effects of perinatal chemical (FM 550) exposure alone or in combination with an early life stressor (paternal absence) on prosocial behavior. Dams were exposed to vehicle (sesame oil) or 1000 µg FM 550 orally via food treats from conception through weaning and the paternal absence groups were generated by removing the sires the day after birth. Adult offspring of both sexes were then subjected to open-field, sociability, and a partner preference test. Paternal deprivation (PD)-related effects included increased anxiety, decreased sociability, and impaired pair-bonding in both sexes. FM 550 effects include heightened anxiety and partner preference in females but reduced partner preference in males. The combination of FM 550 exposure and PD did not exacerbate any behaviors in either sex except for distance traveled by females in the partner preference test and, to a lesser extent, time spent with, and the number of visits to the non-social stimulus by males in the sociability test. FM 550 ameliorated the impacts of parental deprivation on partner preference behaviors in both sexes. This study is significant because it provides evidence that chemical and social stressors can have unique behavioral effects that differ by sex but may not produce worse outcomes in combination.

A Longitudinal Cohort Study of Precocious Puberty and Autism Spectrum Disorder

INTRODUCTION

Autism spectrum disorder (ASD) is defined by persistent deficits in communication, socialization, and stereotypic behaviors. It was previously hypothesized that hormone dysfunction is a frequent occurrence among children diagnosed with an ASD.

OBJECTIVES

A hypothesis-testing epidemiological study examined the relationship between precocious puberty (PP) (a known disorder of childhood sex hormone dysfunction) and ASD diagnoses.

METHODS

The Independent Healthcare Research Database is composed of de-identified linked eligibility and claims health-care records prospectively generated from the Florida Medicaid system. A cohort of 101,736 children eligible for Florida Medicaid from 1990 to 2009 and continuously eligible with ≥10 outpatient office visits during the 120-month period following birth were examined using SAS and StatsDirect software. There were 1,593 children (15,738 person-years) in the ASD diagnosed cohort utilizing the Diagnostic and Statistical Manual of Mental Disorders, 4th revision criteria (the International Code for Disease, 9th revision [ICD-9] codes: 299.00 or 299.80) and 100,143 children (996,835 person-years) in the undiagnosed cohort.

RESULTS

The incidence rate of PP (ICD-9 code: 259.1) was examined using Cox proportional hazards ratio (HR) and frequency models. PP per 10,000 person-years in the ASD cohort (43.2) relative to the undiagnosed cohort (13.7) was significantly increased in frequency modeling (risk ratio = 3.15, p < 0.0001) and Cox proportional HR modeling (adjusted HR = 4.64, p < 0.0001). Further analyses revealed the incidence rate of PP diagnosed after 3 years of age was significantly increased (adjusted HR = 5.16, p < 0.0001) in the ASD cohort relative to the undiagnosed cohort but not for the incidence rate of PP diagnosed before 3 years (adjusted HR = 1.57, p = 0.44).

CONCLUSION

This hypothesis-testing study provides strong evidence of an increased incidence rate of PP among children diagnosed with an ASD.

Scientific Validation of Human Neurosphere Assays for Developmental Neurotoxicity Evaluation

There is a call for a paradigm shift in developmental neurotoxicity (DNT) evaluation, which demands the implementation of faster, more cost-efficient, and human-relevant test systems than current in vivo guideline studies. Under the umbrella of the Organisation for Economic Co-operation and Development (OECD), a guidance document is currently being prepared that instructs on the regulatory use of a DNT in vitro battery (DNT IVB) for fit-for-purpose applications. One crucial issue for OECD application of methods is validation, which for new approach methods (NAMs) requires novel approaches. Here, mechanistic information previously identified in vivo, as well as reported neurodevelopmental adversities in response to disturbances on the cellular and tissue level, are of central importance. In this study, we scientifically validate the Neurosphere Assay, which is based on human primary neural progenitor cells (hNPCs) and an integral part of the DNT IVB. It assesses neurodevelopmental key events (KEs) like NPC proliferation (NPC1ab), radial glia cell migration (NPC2a), neuronal differentiation (NPC3), neurite outgrowth (NPC4), oligodendrocyte differentiation (NPC5), and thyroid hormone-dependent oligodendrocyte maturation (NPC6). In addition, we extend our work from the hNPCs to human induced pluripotent stem cell-derived NPCs (hiNPCs) for the NPC proliferation (iNPC1ab) and radial glia assays (iNPC2a). The validation process we report for the endpoints studied with the Neurosphere Assays is based on 1) describing the relevance of the respective endpoints for brain development, 2) the confirmation of the cell type-specific morphologies observed in vitro, 3) expressions of cell type-specific markers consistent with those morphologies, 4) appropriate anticipated responses to physiological pertinent signaling stimuli and 5) alterations in specific in vitro endpoints upon challenges with confirmed DNT compounds. With these strong mechanistic underpinnings, we posit that the Neurosphere Assay as an integral part of the DNT in vitro screening battery is well poised for DNT evaluation for regulatory purposes.

In utero exposure to endocrine disruptors and developmental neurotoxicity: Implications for behavioural and neurological disorders in adult life

Endocrine disrupting chemicals (EDCs) are a class of environmental toxicants that interfere with the endocrine system, resulting in developmental malformations, reproductive disorders, and alterations to immune and nervous system function. The emergence of screening studies identifying these chemicals in fetal developmental matrices such as maternal blood, placenta and amniotic fluid has steered research focus towards elucidation of in utero effects of exposure to these chemicals, as their capacity to cross the placenta and reach the fetus was established. The presence of EDCs, a majority of which are estrogen mimics, in the fetal environment during early development could potentially affect neurodevelopment, with implications for behavioural and neurological disorders in adult life. This review summarizes studies in animal models and human cohorts that aim to elucidate mechanisms of action of EDCs in the context of neurodevelopment and disease risk in adult life. This is a significant area of study as early brain development is heavily mediated by estrogen and could be particularly sensitive to EDC exposure. A network analysis presented using genes summarized in this review, further show a significant association with disorders such as major depressive disorder, alcoholic disorder, psychotic disorders and autism spectrum disorder. Functional outcomes such as alterations in memory, behaviour, cognition, learning memory, feeding behaviour and regulation of ion transport are also highlighted. Interactions between genes, receptors and signaling pathways like NMDA glutamate receptor activity, 5-hydroxytryptamine receptor activity, Ras-activated Ca₂⁺ influx and Grin2A interactions, provide further potential mechanisms of action of EDCs in mediating brain function. Taken together with the growing pool of human and animal studies, this review summarizes current status of EDC neurotoxicity research, limitations and future directions of study for researchers.

Adsorption behavior of bisphenol A on bentonite-loess mixtures

The leakage of chemical compounds in landfill leachate led to serious environment pollution, especially, the compounds termed endocrine disruptors such as bisphenol A (BPA). It is very important to study the adsorption behavior of endocrine disruptors in modified soil for predicting and evaluating the potential harm of endocrine disruptors to the soil. Bentonite-amended Chinese loess mixtures, with various proportions of bentonite, were used for the removal of BPA from an aqueous solution. A batch test was used to investigate the adsorption properties of bisphenol A on bentonite and Chinese loess mixtures. The influences of bentonite proportion, temperature, reaction time, pH, and soil-water ratios on the adsorption process were considered. The Fourier transform infrared spectra (FTIR) was used to clarify the change of functional groups before and after the adsorption of BPA on soil. The adsorption mechanism of BPA on soil was discussed preliminary. The results show that the addition of bentonite to the loess can improve the adsorption rate of BPA. The adsorption of BPA was mainly a spontaneous, exothermic, entropy decreasing physical adsorption process. The interaction between bentonite content and reaction concentration had a beneficial effect on BPA adsorption. The linear relationship between bentonite content and adsorption capacity was obtained. The results indicate that bentonite amended loess can provide a good liner for BPA.

Autism-Related Transcription Factors Underlying the Sex-Specific Effects of Prenatal Bisphenol A Exposure on Transcriptome-Interactome Profiles in the Offspring Prefrontal Cortex

Bisphenol A (BPA) is an environmental risk factor for autism spectrum disorder (ASD). BPA exposure dysregulates ASD-related genes in the hippocampus and neurological functions of offspring. However, whether prenatal BPA exposure has an impact on genes in the prefrontal cortex, another brain region highly implicated in ASD, and through what mechanisms have not been investigated. Here, we demonstrated that prenatal BPA exposure disrupts the transcriptome-interactome profiles of the prefrontal cortex of neonatal rats. Interestingly, the list of BPA-responsive genes was significantly enriched with known ASD candidate genes, as well as genes that were dysregulated in the postmortem brain tissues of ASD cases from multiple independent studies. Moreover, several differentially expressed genes in the offspring's prefrontal cortex were the targets of ASD-related transcription factors, including AR, ESR1, and RORA. The hypergeometric distribution analysis revealed that BPA may regulate the expression of such genes through these transcription factors in a sex-dependent manner. The molecular docking analysis of BPA and ASD-related transcription factors revealed novel potential targets of BPA, including RORA, SOX5, TCF4, and YY1. Our findings indicated that prenatal BPA exposure disrupts ASD-related genes in the offspring's prefrontal cortex and may increase the risk of ASD through sex-dependent molecular mechanisms, which should be investigated further.

Estrogen Receptor β as a Candidate Regulator of Sex Differences in the Maternal Immune Activation Model of ASD

Interestingly, more males are diagnosed with autism spectrum disorder (ASD) than females, yet the mechanism behind this difference is unclear. Genes on the sex chromosomes and differential regulation by sex steroid hormones and their receptors are both candidate mechanisms to explain this sex-dependent phenotype. Nuclear receptors (NRs) are a large family of transcription factors, including sex hormone receptors, that mediate ligand-dependent transcription and may play key roles in sex-specific regulation of immunity and brain development. Infection during pregnancy is known to increase the probability of developing ASD in humans, and a mouse model of maternal immune activation (MIA), which is induced by injecting innate immune stimulants into pregnant wild-type mice, is commonly used to study ASD. Since this model successfully recaptures the behavioral phenotypes and male bias observed in ASD, we will discuss the potential role of sex steroid hormones and their receptors, especially focusing on estrogen receptor (ER)β, in MIA and how this signaling may modulate transcription and subsequent inflammation in myeloid-lineage cells to contribute to the etiology of this neurodevelopmental disorder.

Sex-specific Disruption of the Prairie Vole Hypothalamus by Developmental Exposure to a Flame Retardant Mixture

Prevalence of neurodevelopmental disorders (NDDs) with social deficits is conspicuously rising, particularly in boys. Flame retardants (FRs) have long been associated with increased risk, and prior work by us and others in multiple species has shown that developmental exposure to the common FR mixture Firemaster 550 (FM 550) sex-specifically alters socioemotional behaviors including anxiety and pair bond formation. In rats, FRs have also been shown to impair aspects of osmoregulation. Because vasopressin (AVP) plays a role in both socioemotional behavior and osmotic balance we hypothesized that AVP and its related nonapeptide oxytocin (OT) would be vulnerable to developmental FM 550 exposure. We used the prairie vole (Microtus ochrogaste) to test this because it is spontaneously prosocial. Using siblings of prairie voles used in a prior study that assessed behavioral deficits resulting from developmental FM 550 exposure across 3 doses, here we tested the hypothesis that FM 550 sex-specifically alters AVP and OT neuronal populations in critical nuclei, such as the paraventricular nucleus (PVN), that coordinate those behaviors, as well as related dopaminergic (determined by tyrosine hydroxylase (TH) immunolabeling) populations. Exposed females had fewer AVP neurons in the anterior PVN and more A13 TH neurons in the zona incerta than controls. By contrast, in FM 550 males, A13 TH neuron numbers in the zona incerta were decreased but only in 1 dose group. These results expand on previous work showing evidence of endocrine disruption of OT/AVP pathways, including to subpopulations of PVN AVP neurons that coordinate osmoregulatory functions in the periphery.

Autism Spectrum Disorders

This article describes the current understanding of the identification, classification, and diagnosis of autism spectrum disorder (ASD) as it relates to the practice of primary care providers. In addition, the most updated information regarding risk factors, as well as effective treatment strategies are provided. Although primary care providers are not typically the experts in ASD treatment, they constitute a critical component of the care team responsible for early identification and intervention initiation for patients with ASD.

Endocrine Disrupting Chemicals, Hormone Receptors, and Acne Vulgaris: A Connecting Hypothesis

The relationship between endocrine disrupting chemicals (EDCs) and the pathogenesis of acne vulgaris has yet to be explored in the literature. Acne vulgaris is a chronic inflammatory skin disease of the pilosebaceous unit. The pathogenesis of acne involves several hormonal pathways, including androgens, insulin-like growth factor 1(IGF-1), estrogens, and corticosteroids. EDCs influence these pathways primarily through two mechanisms: altering endogenous hormone levels and interfering with hormone receptor function. This review article describes the mechanistic links between EDCs and the development of acne lesions. Highlighted is the contributory role of androgen receptor ligands, such as bisphenol A (BPA) and mono-2-ethylhexyl Phthalate (MEHP), via upregulation of lipogenic genes and resultant exacerbation of cholesterol synthesis. Additionally discussed is the protective role of phytoestrogen EDCs in counteracting androgen-induced sebocyte maturation through attenuation of PPARy transcriptional activity (i.e., resveratrol) and restoration of estrogen-regulated TGF-B expression in skin cells (i.e., genistein). Examination of the relationship between EDCs and acne vulgaris may inform adjunctive avenues of treatment such as limiting environmental exposures, and increasing low-glycemic, plant-rich foods in the diet. With a better understanding of the cumulative role that EDCs play in acne, clinicians can be better equipped to treat and ultimately improve the lives of their patients.

Aqueous adsorption of bisphenol A over a porphyrinic porous organic polymer

A new porphyrinic porous organic polymer (PPOP) with high stability and excellent textural properties (929 m²/g surface area with 0.73 cm³/g pore volume) was made via the Friedel-Crafts reaction and applied for bisphenol A (BPA) adsorption in water. The material was examined by X-ray diffraction, N₂ adsorption-desorption isotherms, scanning electron microscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, and solid-state ¹³C CP-MAS nuclear magnetic resonance spectroscopy. PPOP was proven highly effective for capturing BPA among the many adsorbent materials investigated. The Langmuir model could closely match the adsorption isotherm data with a high adsorption amount of ca. 653 mg/g at 25 °C. Approximately 95% of BPA was adsorbed in 50 min, and the pseudo-second-order kinetic model satisfactorily described the adsorption behavior. This adsorption process was exothermic (ΔH° = -39.10 kJ/mol), and the capacity gradually decreased with increasing pH. Spectroscopic analyses indicated that the BPA adsorption on PPOP was affected by (1) π-π interaction between BPA and the aromatic constituents of PPOP, (2) hydrogen bonding between the N sites of porphyrin units in PPOP and the hydroxyl group of BPA and, and (3) hydrophobic interactions. PPOP was easily regenerated after acetone washing, and >98% efficiency was observed throughout the five repeated adsorption-desorption cycles.

Sex differences in the effects of prenatal bisphenol A exposure on autism-related genes and their relationships with the hippocampus functions

Our recent study has shown that prenatal exposure to bisphenol A (BPA) altered the expression of genes associated with autism spectrum disorder (ASD). In this study, we further investigated the effects of prenatal BPA exposure on ASD-related genes known to regulate neuronal viability, neuritogenesis, and learning/memory, and assessed these functions in the offspring of exposed pregnant rats. We found that prenatal BPA exposure increased neurite length, the number of primary neurites, and the number of neurite branches, but reduced the size of the hippocampal cell body in both sexes of the offspring. However, in utero exposure to BPA decreased the neuronal viability and the neuronal density in the hippocampus and impaired learning/memory only in the male offspring while the females were not affected. Interestingly, the expression of several ASD-related genes (e.g. Mief2, Eif3h, Cux1, and Atp8a1) in the hippocampus were dysregulated and showed a sex-specific correlation with neuronal viability, neuritogenesis, and/or learning/memory. The findings from this study suggest that prenatal BPA exposure disrupts ASD-related genes involved in neuronal viability, neuritogenesis, and learning/memory in a sex-dependent manner, and these genes may play an important role in the risk and the higher prevalence of ASD in males subjected to prenatal BPA exposure.

Intrauterine Exposure to Acetaminophen and Adverse Developmental Outcomes: Epidemiological Findings and Methodological Issues

PURPOSE OF REVIEW

Acetaminophen (or paracetamol) is one of the most commonly used medications during pregnancy. We reviewed recent epidemiological evidence regarding intrauterine exposure to acetaminophen and risk for asthma, neurodevelopment disorders, and reproductive health in childhood.

RECENT FINDINGS

An increasing number of cohort studies have suggested that maternal use of acetaminophen during pregnancy was associated with increased risk for asthma; neurodevelopmental disorders, especially ADHD and behavioral problems; and genital malformations in the offspring. Oxidative stress and inflammation or endocrine effects are plausible shared biological mechanisms for the exposure to influence multiple developmental outcomes. We discussed methodological challenges that can threaten the validity of these observational data, including confounding and measurement errors. Novel statistical methods and research designs that can be used to mitigate these issues were introduced. Given the high prevalence of use, findings regarding intrauterine exposure to acetaminophen on multiple child health outcomes raise concerns. Research on causal and non-causal mechanisms that might explain these associations should be a priority.

Applications of the SR4G Transgenic Zebrafish Line for Biomonitoring of Stress-Disrupting Compounds: A Proof-of-Concept Study

Transgenic zebrafish models have been successfully used in biomonitoring and risk assessment studies of environmental pollutants, including xenoestrogens, pesticides, and heavy metals. We employed zebrafish larva (transgenic SR4G line) with a cortisol-inducible green fluorescence protein reporter (eGFP) as a model to detect stress responses upon exposure to compounds with environmental impact, including bisphenol A (BPA), vinclozolin (VIN), and fluoxetine (FLX). Cortisol, fluorescence signal, and mRNA levels of eGFP and 11 targeted genes were measured in a homogenized pool of zebrafish larvae, with six experimental replicates for each endpoint. Eleven targeted genes were selected according to their association with stress-axis and immediate early response class of genes. Hydrocortisone (CORT)and dexamethasone (DEX) were used as positive and negative controls, respectively. All measurements were done in two unstressed and stressed condition using standardized net handling as the stressor. A significant positive linear correlation between cortisol levels and eGFP mRNA levels was observed (r> 0.9). Based on eGFP mRNA levels in unstressed and stressed larvae two predictive models were trained (Random Forest and Logistic Regression). Both these models could correctly predict the blunted stress response upon exposure to BPA, VIN, FLX and the negative control, DEX. The negative predictive value (NPV) of these models were 100%. Similar NPV was observed when the predictive models trained based on the mRNA levels of the eleven assessed genes. Measurement of whole-body fluorescence intensity signal was not significant to detect blunted stress response. Our findings support the use of SR4G transgenic larvae as an in vivo biomonitoring model to screen chemicals for their stress-disrupting potentials. This is important because there is increasing evidence that brief exposures to environmental pollutants modify the stress response and critical coping behaviors for several generations.

A comprehensive review of the neurobehavioral effects of bisphenol S and the mechanisms of action: New insights from in vitro and in vivo models

The normal brain development and function are delicately driven by an ever-changing milieu of steroid hormones arising from fetal, placental, and maternal origins. This reliance on the neuroendocrine system sets the stage for the exquisite sensitivity of the central nervous system to the adverse effects of endocrine-disrupting chemicals (EDCs). Bisphenol A (BPA) is one of the most common EDCs which has been a particular focus of environmental concern for decades due to its widespread nature and formidable threat to human and animal health. The heightened regulatory actions and the scientific and public concern over the adverse health effects of BPA have led to its replacement with a suite of structurally similar but less known alternative chemicals. Bisphenol S (BPS) is the main substitute for BPA that is increasingly being used in a wide array of consumer and industrial products. Although it was considered to be a safe BPA alternative, mounting evidence points to the deleterious effects of BPS on a wide range of neuroendocrine functions in animals. In addition to its reproductive toxicity, recent experimental efforts indicate that BPS has a considerable potential to induce neurotoxicity and behavioral dysfunction. This review analyzes the current state of knowledge regarding the neurobehavioral effects of BPS and discusses its potential mode of actions on several aspects of the neuroendocrine system. We summarize the role of certain hormones and their signaling pathways in the regulation of brain and behavior and discuss how BPS induces neurotoxicity through interactions with these pathways. Finally, we review potential links between BPS exposure and aberrant neurobehavioral functions in animals and identify key knowledge gaps and hypotheses for future research.

Children's Environmental Health: A Systems Approach for Anticipating Impacts from Chemicals

Increasing numbers of chemicals are on the market and present in consumer products. Emerging evidence on the relationship between environmental contributions and prevalent diseases suggests associations between early-life exposure to manufactured chemicals and a wide range of children’s health outcomes. Using current assessment methodologies, public health and chemical management decisionmakers face challenges in evaluating and anticipating the potential impacts of exposure to chemicals on children’s health in the broader context of their physical (built and natural) and social environments. Here, we consider a systems approach to address the complexity of children’s environmental health and the role of exposure to chemicals during early life, in the context of nonchemical stressors, on health outcomes. By advancing the tools for integrating this more complex information, the scope of considerations that support chemical management decisions can be extended to include holistic impacts on children’s health.

Phenotypic Subtyping and Re-Analysis of Existing Methylation Data from Autistic Probands in Simplex Families Reveal ASD Subtype-Associated Differentially Methylated Genes and Biological Functions

Autism spectrum disorder (ASD) describes a group of neurodevelopmental disorders with core deficits in social communication and manifestation of restricted, repetitive, and stereotyped behaviors. Despite the core symptomatology, ASD is extremely heterogeneous with respect to the severity of symptoms and behaviors. This heterogeneity presents an inherent challenge to all large-scale genome-wide omics analyses. In the present study, we address this heterogeneity by stratifying ASD probands from simplex families according to the severity of behavioral scores on the Autism Diagnostic Interview-Revised diagnostic instrument, followed by re-analysis of existing DNA methylation data from individuals in three ASD subphenotypes in comparison to that of their respective unaffected siblings. We demonstrate that subphenotyping of cases enables the identification of over 1.6 times the number of statistically significant differentially methylated regions (DMR) and DMR-associated genes (DAGs) between cases and controls, compared to that identified when all cases are combined. Our analyses also reveal ASD-related neurological functions and comorbidities that are enriched among DAGs in each phenotypic subgroup but not in the combined case group. Moreover, relational gene networks constructed with the DAGs reveal signaling pathways associated with specific functions and comorbidities. In addition, a network comprised of DAGs shared among all ASD subgroups and the combined case group is enriched in genes involved in inflammatory responses, suggesting that neuroinflammation may be a common theme underlying core features of ASD. These findings demonstrate the value of phenotype definition in methylomic analyses of ASD and may aid in the development of subtype-directed diagnostics and therapeutics.

Endocrine Insights into the Pathophysiology of Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a class of neurodevelopmental disorders that affects males more frequently than females. Numerous genetic and environmental risk factors have been suggested to contribute to the development of ASD. However, no one factor can adequately explain either the frequency of the disorder or the male bias in its prevalence. Gonadal, thyroid, and glucocorticoid hormones all contribute to normal development of the brain, hence perturbations in either their patterns of secretion or their actions may constitute risk factors for ASD. Environmental factors may contribute to ASD etiology by influencing the development of neuroendocrine and neuroimmune systems during early life. Emerging evidence suggests that the placenta may be particularly important as a mediator of the actions of environmental and endocrine risk factors on the developing brain, with the male being particularly sensitive to these effects. Understanding how various risk factors integrate to influence neural development may facilitate a clearer understanding of the etiology of ASD.

Autism spectrum disorder at the crossroad between genes and environment: contributions, convergences, and interactions in ASD developmental pathophysiology

The complex pathophysiology of autism spectrum disorder encompasses interactions between genetic and environmental factors. On the one hand, hundreds of genes, converging at the functional level on selective biological domains such as epigenetic regulation and synaptic function, have been identified to be either causative or risk factors of autism. On the other hand, exposure to chemicals that are widespread in the environment, such as endocrine disruptors, has been associated with adverse effects on human health, including neurodevelopmental disorders. Interestingly, experimental results suggest an overlap in the regulatory pathways perturbed by genetic mutations and environmental factors, depicting convergences and complex interplays between genetic susceptibility and toxic insults. The pervasive nature of chemical exposure poses pivotal challenges for neurotoxicological studies, regulatory agencies, and policy makers. This highlights an emerging need of developing new integrative models, including biomonitoring, epidemiology, experimental, and computational tools, able to capture real-life scenarios encompassing the interaction between chronic exposure to mixture of substances and individuals' genetic backgrounds. In this review, we address the intertwined roles of genetic lesions and environmental insults. Specifically, we outline the transformative potential of stem cell models, coupled with omics analytical approaches at increasingly single cell resolution, as converging tools to experimentally dissect the pathogenic mechanisms underlying neurodevelopmental disorders, as well as to improve developmental neurotoxicology risk assessment.

Enhanced removal of the endocrine disruptor compound Bisphenol A by adsorption onto green-carbon materials. Effect of real effluents on the adsorption process

The high exposure to the endocrine disrupting compounds (EDC) in water represents a relevant issue for the health of living beings. The xenoestrogen Bisphenol A (BPA), a suspected EDC, is an industrial additive broadly used for manufacturing polycarbonate and epoxy resins. Due to its harmful effect in humans and the aquatic environment, an efficient method to remove BPA from wastewater is urgently required. The present work aims to study the adsorption of BPA from aqueous solutions onto carbonaceous materials, e.g., a synthesized carbon xerogel (RFX), a chemical-activated carbon from Kraft lignin (KLP) and a commercial activated carbon (F400) for comparative purposes. Batch kinetic and adsorption tests of BPA in ultrapure water were accomplished, finding higher adsorption capacities of BPA onto both F400 activated carbon (q_sat = 407 mg g^-1) and the biochar KLP (q_sat = 220 mg g^-1), versus to that obtained for the xerogel (q_sat = 78 mg g^-1). Furthermore, kinetic experiments revealed faster kinetic adsorption for RFX and KLP materials, achieving the equilibrium time within 24 h, attributed to their more-opened porous structure. Pseudo-first order, pseudo-second order, Elovich, intra-particle diffusion and film diffusion models were used to fit the experimental data. Thus, the BPA adsorption isotherms were analysed by Langmuir, Freundlich, Sips, Redlich-Peterson and Dual-site Langmuir (DLS) isotherm models.In addition, the influence of different aqueous matrices, such as a hospital wastewater, a wastewater treatment plant (WWTP) effluent and a river water, on BPA removal efficiency has been explored. These adsorption tests revealed a clear competitive effect between the target compound (BPA) and the natural organic matter content (NOM) present in the matrices for the active sites, resulting in a high decreasing of BPA adsorption removal.

Prenatal exposure to bisphenol A alters the transcriptome-interactome profiles of genes associated with Alzheimer's disease in the offspring hippocampus

Our recent study revealed that prenatal exposure to bisphenol A (BPA) disrupted the transcriptome profiles of genes in the offspring hippocampus. In addition to genes linked to autism, several genes associated with Alzheimer’s disease (AD) were found to be differentially expressed, although the association between BPA-responsive genes and AD-related genes has not been thoroughly investigated. Here, we demonstrated that in utero BPA exposure also disrupted the transcriptome profiles of genes associated with neuroinflammation and AD in the hippocampus. The level of NF-κB protein and its AD-related target gene Bace1 were significantly increased in the offspring hippocampus in a sex-dependent manner. Quantitative RT-PCR analysis also showed an increase in the expression of Tnf gene. Moreover, the reanalysis of transcriptome profiling data from several previously published BPA studies consistently showed that BPA-responsive genes were significantly associated with top AD candidate genes. The findings from this study suggest that maternal BPA exposure may increase AD risk in offspring by dysregulating genes associated with AD neuropathology and inflammation and reveal a possible relationship between AD and autism, which are linked to the same environmental factor. Sex-specific effects of prenatal BPA exposure on the susceptibility of AD deserve further investigation.

Nutritional and environmental contributions to Autism Spectrum Disorders: Focus on nutrigenomics as complementary therapy

The prevalence of autism spectrum disorders (ASD) has risen sharply in the last 30 years, posing a major public health concern and a big emotional and financial challenge for families. While the underlying causes remain to be fully elucidated, evidence shows moderate genetic heritability contribution, but heavy environmental influence. Over the last decades, modern lifestyle has deeply changed our eating, rest, and exercise habits, while exposure to air, water, and food chemical pollution has increased due to indiscriminate use of pesticides, food additives, adjuvants, and antibiotics. The result is a drastic change in the quality of our energy source input, and an overload for antioxidant and detoxification pathways that compromises normal metabolism and homeostasis. Current research shows high prevalence of food selectivity and/or food allergy among children with autism, resulting in essential micronutrient deficits that may trigger or aggravate physical and cognitive symptoms. Nutrigenomics is an emerging discipline that focuses on genotype-micronutrient interaction, and a useful approach to tailor low risk, personalized interventions through diet and micronutrient supplementation. Here, we review available literature addressing the role of micronutrients in the symptomatology of ASD, the metabolic pathways involved, and their therapeutic relevance. Personalized and supervised supplementation according to individual needs is suggested as a complement of traditional therapies to improve outcome both for children with autism and their families.

Cell Therapy Targets for Autism Spectrum Disorders: Hopes, Challenges and Future Directions

Autism spectrum disorders as a group of pediatric neurodevelopmental diseases is a crucial part of the worldwide disabilities which have influence in communication skills, social interactions, and ability to understand the concepts. The precise pathophysiology of autism spectrum disorders due to the abundance of involved mechanisms is unknown. Some of these involved mechanisms are related to genetic factors, chronic neuro inflammation, mitochondrial dysfunction, oxidative stress, immune dysregulation, hormonal imbalance, and environmental factors. Current main treatments for autisms are behavioral, nutritional and medical therapies, however there is not definitive treatment approach. Therein, more novel therapies are still required to improve the symptoms. Several preclinical and clinical evidence were shown that stem cell therapy is a potential treatment option for autism spectrum disorders individuals. Considering the significant factors which can affect the outcome of stem cell therapeutic effects including stem cell types, route and dosage of administration, and mechanism of activity along with selecting best animal models can be very important in performing clinical trials.

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.

Stem cell models of human synapse development and degeneration

Many brain disorders exhibit altered synapse formation in development or synapse loss with age. To understand the complexities of human synapse development and degeneration, scientists now engineer neurons and brain organoids from human-induced pluripotent stem cells (hIPSC). These hIPSC-derived brain models develop both excitatory and inhibitory synapses and functional synaptic activity. In this review, we address the ability of hIPSC-derived brain models to recapitulate synapse development and insights gained into the molecular mechanisms underlying synaptic alterations in neuronal disorders. We also discuss the potential for more accurate human brain models to advance our understanding of synapse development, degeneration, and therapeutic responses.

Effects of Lactobacillus plantarum PS128 on Children with Autism Spectrum Disorder in Taiwan: A Randomized, Double-Blind, Placebo-Controlled Trial

This four-week, randomized, double-blind, placebo-controlled study investigated the effects of Lactobacillus plantarum PS128 (PS128) on boys with autism spectrum disorder (ASD) aged 7-15 in Taiwan. All subjects fulfilled the criteria for ASD diagnosis of DSM-V and the Autism Diagnostic Interview-Revised (ADI-R). Questionnaires used for the primary outcome measure include the Autism Behavior Checklist-Taiwan version (ABC-T), the Social Responsiveness Scale (SRS) and the Child Behavior Checklist (CBCL). The Swanson, Nolan, and Pelham-IV-Taiwan version (SNAP-IV) and the Clinical Global Impression-improvement (CGI-I) were used for the secondary outcome measure. The results showed that PS128 ameliorated opposition/defiance behaviors, and that the total score of SNAP-IV for younger children (aged 712) improved significantly compared with the placebo group. Additionally, several elements were also notably improved in the PS128 group after 28-day consumption of PS128. Further studies are needed to better clarify the effects of PS128 for younger children with ASD on broader symptoms.

Environmental Chemicals and Autism: A Scoping Review of the Human and Animal Research

BACKGROUND

Estimates of autism prevalence have increased dramatically over the past two decades. Evidence suggests environmental factors may contribute to the etiology of the disorder.

OBJECTIVES

This scoping review aimed to identify and categorize primary research and reviews on the association between prenatal and early postnatal exposure to environmental chemicals and the development of autism in epidemiological studies and rodent models of autism.

METHODS

PubMed was searched through 8 February 2018. Included studies assessed exposure to environmental chemicals prior to 2 months of age in humans or 14 d in rodents. Rodent studies were considered relevant if they included at least one measurement of reciprocal social communicative behavior or repetitive and stereotyped behavior. Study details are presented in interactive displays using Tableau Public.

RESULTS

The search returned 21,603 unique studies, of which 54 epidemiological studies, 46 experimental rodent studies, and 50 reviews were deemed relevant, covering 152 chemical exposures. The most frequently studied exposures in humans were particulate matter ([Formula: see text]), mercury ([Formula: see text]), nonspecific air pollution ([Formula: see text]), and lead ([Formula: see text]). In rodent studies, the most frequently studied exposures were chlorpyrifos ([Formula: see text]), mercury ([Formula: see text]), and lead ([Formula: see text]).

DISCUSSION

Although research is growing rapidly, wide variability exists in study design and conduct, exposures investigated, and outcomes assessed. Conclusions focus on recommendations to guide development of best practices in epidemiology and toxicology, including greater harmonization across these fields of research to more quickly and efficiently identify chemicals of concern. In particular, we recommend chlorpyrifos, lead, and polychlorinated biphenyls (PCBs) be systematically reviewed in order to assess their relationship with the development of autism. There is a pressing need to move forward quickly and efficiently to understand environmental influences on autism in order to answer current regulatory questions and inform treatment and prevention efforts. https://doi.org/10.1289/EHP4386.

Phenotypic subgrouping and multi-omics analyses reveal reduced diazepam-binding inhibitor (DBI) protein levels in autism spectrum disorder with severe language impairment

BACKGROUND

The mechanisms underlying autism spectrum disorder (ASD) remain unclear, and clinical biomarkers are not yet available for ASD. Differences in dysregulated proteins in ASD have shown little reproducibility, which is partly due to ASD heterogeneity. Recent studies have demonstrated that subgrouping ASD cases based on clinical phenotypes is useful for identifying candidate genes that are dysregulated in ASD subgroups. However, this strategy has not been employed in proteome profiling analyses to identify ASD biomarker proteins for specific subgroups.

METHODS

We therefore conducted a cluster analysis of the Autism Diagnostic Interview-Revised (ADI-R) scores from 85 individuals with ASD to predict subgroups and subsequently identified dysregulated genes by reanalyzing the transcriptome profiles of individuals with ASD and unaffected individuals. Proteome profiling of lymphoblastoid cell lines from these individuals was performed via 2D-gel electrophoresis, and then mass spectrometry. Disrupted proteins were identified and compared to the dysregulated transcripts and reported dysregulated proteins from previous proteome studies. Biological functions were predicted using the Ingenuity Pathway Analysis (IPA) program. Selected proteins were also analyzed by Western blotting.

RESULTS

The cluster analysis of ADI-R data revealed four ASD subgroups, including ASD with severe language impairment, and transcriptome profiling identified dysregulated genes in each subgroup. Screening via proteome analysis revealed 82 altered proteins in the ASD subgroup with severe language impairment. Eighteen of these proteins were further identified by nano-LC-MS/MS. Among these proteins, fourteen were predicted by IPA to be associated with neurological functions and inflammation. Among these proteins, diazepam-binding inhibitor (DBI) protein was confirmed by Western blot analysis to be expressed at significantly decreased levels in the ASD subgroup with severe language impairment, and the DBI expression levels were correlated with the scores of several ADI-R items.

CONCLUSIONS

By subgrouping individuals with ASD based on clinical phenotypes, and then performing an integrated transcriptome-proteome analysis, we identified DBI as a novel candidate protein for ASD with severe language impairment. The mechanisms of this protein and its potential use as an ASD biomarker warrant further study.

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.

Exposure to bisphenol A: current levels from food intake are toxic to human cells

In the present work, cell lines of different origin were exposed to BPA levels from food intake reported elsewhere. Specifically, we used an in vitro assay to determine cytotoxicity of BPA in three cell lines: MCF7 (breast cancer), PC3 (prostate cancer) and 3T3-L1 (mouse fibroblast). Cytotoxic effects were observed at concentrations higher than 50 μg/mL which is above the involuntary exposure level of BPA described before in fresh, canned and frozen foods and beverages. Furthermore, medial inhibitory concentrations (IC50) of 85.17 μg/mL and 88.48 μg/mL were observed for PC3 and 3T3-L1, respectively, and a slightly lower IC50 of 64.67 μg/mL for MCF7. These results highlight BPA's toxicity potential at current levels from food intake. The cell line-dependent divergent response to BPA reported herein is discussed.

The Role of Environmental Disruptor Chemicals in the Development of Non Communicable Disease

The increasing prevalence of non communicable diseases (NCDs) poses main challenges to global public health. Various environmental exposures to different chemicals and pollutants might interact with genetic and epigenetic mechanisms resulting in the development of NCDs. Among these environmental exposures, endocrine disrupting chemicals (EDCs) consist of a group of compounds with potential adverse health effects and the interference with the endocrine system. They are mostly used in food constituents, packaging industries and pesticides. Growing number of in vitro, in vivo, and epidemiological studies documented the link of EDC exposure with obesity, diabetes, and metabolic syndrome, which are the underlying factors for development of NCDs. Prevention of exposure to EDCs and reduction of their production should be underscored in strategies for primordial prevention of NCDs.

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.