Di-(2-ethylhexyl) phthalate and autism spectrum disorders

Di (2-ethylhexyl) phthalate alters neurobehavioral responses and oxidative status, architecture, and GFAP and BDNF signaling in juvenile rat's brain: Protective role of Coenzyme10

Di-(2-ethylhexyl) phthalate (DEHP), a phthalate plasticizer, is widely spread in the environment, presenting hazards to human health and food safety. Hence, this study examined the probable preventive role of coenzyme10 (CQ10) (10 mg/kg.b.wt) against DEHP (500 mg/kg.wt) - induced neurotoxic and neurobehavioral impacts in juvenile (34 ± 1.01g and 3 weeks old) male Sprague Dawley rats in 35-days oral dosing trial. The results indicated that CQ10 significantly protected against DEHP-induced memory impairment, anxiety, depression, spatial learning disorders, and repetitive/stereotypic-like behavior. Besides, the DEHP-induced depletion in dopamine and gamma amino butyric acid levels was significantly restored by CQ10. Moreover, CQ10 significantly protected against the exhaustion of CAT, GPx, SOD, GSH, and GSH/GSSG ratio, as well as the increase in malondialdehyde, Caspas-3, interleukin-6, and tumor necrosis factor-alpha brain content accompanying with DEHP exposure. Furthermore, CQ10 significantly protected the brain from the DEHP-induced neurodegenerative alterations. Also, the increased immunoexpression of brain-derived neurotrophic factor, not glial fibrillary acidic protein, in the cerebral, hippocampal, and cerebellar brain tissues due to DEHP exposure was alleviated with CQ10. This study's findings provide conclusive evidence that CQ10 has the potential to be used as an efficient natural protective agent against the neurobehavioral and neurotoxic consequences of DEHP.

A Mixture of Urinary Phthalate Metabolite Concentrations During Pregnancy and Offspring Social Responsiveness Scale Scores

BACKGROUND

Phthalates are a group of chemicals with ubiquitous exposure worldwide. Exposures to phthalates during pregnancy may play a role in autism spectrum disorder (ASD) etiology by disrupting hormone levels or directly impacting fetal neurodevelopment. However, there is little research quantifying the aggregate effect of phthalates on child ASD-related behaviors.

METHODS

We used data from two prospective pregnancy and birth cohorts-the Health Outcomes and Measures of the Environment (HOME) and the Early Autism Risk Longitudinal Investigation (EARLI). HOME is a general population cohort while participants in EARLI were at higher familial risk for ASD. Using quantile g-computation and linear regression models, we assessed the joint and individual associations of a mixture of six phthalate metabolites during pregnancy with child ASD-related traits measured by Social Responsiveness Scale (SRS) scores at ages 3-8 years.

RESULTS

Our analyses included 271 participants from HOME and 166 participants from EARLI. There were imprecise associations between the phthalate mixture and SRS total raw scores in HOME (difference in SRS scores per decile increase in every phthalate = 1.3; 95% confidence interval [CI] = -0.2, 2.8) and EARLI (difference in SRS scores per decile increase in every phthalate = -0.9; 95% CI = -3.5, 1.7).

CONCLUSIONS

The cohort-specific effect sizes of the pthalates-SRS associations were small and CIs were imprecise. These results suggest that if there are associations between phthalate metabolites during pregnancy and child SRS scores, they may differ across populations with different familial liabilities. Further studies with larger sample sizes are warranted.

Subchronic exposure to di-(2-ethylhexyl) phthalate (DEHP) elicits blood-brain barrier dysfunction and neuroinflammation in male C57BL/6J mice

BACKGROUND

Exposure to di-(2-ethylhexyl) phthalate (DEHP) can cause neurotoxicity but the mechanism is not clear. Blood brain barrier (BBB) is one of the most important tissues to protect the brain. However, whether DEHP can disrupt the BBB or not remains unclear. The objective of this study is to investigate the potential effects of subchronic DEHP exposure on BBB integrity and discuss the role of BBB in DEHP inducible neurotoxicity with an emphasis on neuroinflammatory responses. Male adult C57BL/6J mice were orally administered with vehicle or 200 or 750 mg/kg/day DEHP for 90 days. Subchronic exposure to high-dose DEHP increased water intake but decreased body weight and brain weight. The concentrations of DEHP metabolites increased in serum from all DEHP-exposed groups while increased in brain only from the high-dose group. DEHP induced neurobehavioural alterations and damaged hippocampal neurons. DEHP increased BBB permeability by Evans blue (EB) extravasation and decreased tight junction proteins (ZO-1, occludin, and claudin-5) while presenting a neuroinflammatory feature characterized by the upregulated inflammatory mediators TNF-α and the NLRP3/caspase-1/IL-1β inflammasome pathway. Our data provide new insights into neurotoxicity caused by subchronic DEHP exposure, which is probably involved in BBB dysfunction and neuroinflammatory responses.

Neurotoxicity and the potential molecular mechanisms of mono-2-ethylhexyl phthalic acid (MEHP) in zebrafish

Mono-2-ethylhexyl phthalic acid (MEHP) is the most toxic metabolite of plasticizer di-2-ethylhexyl phthalic acid (DEHP), and there is limited information available on the effects of MEHP on neurotoxicity. This study aims to examine the neurotoxicity of MEHP and preliminarily explore its potential molecular mechanisms. We found that MEHP impeded the growth of zebrafish embryos and the neurodevelopmental-related gene expression at environmentally relevant concentrations. MEHP exposure also induces oxidative stress response and brain cell apoptosis accompanied by a decrease in acetylcholinesterase (AChE) activity in zebrafish larvae. RNA-Seq and bioinformatics analysis showed that MEHP treatment altered the nervous system, neurogenic diseases, and visual perception pathways. The locomotor activity in dark-to-light cycles and phototaxis test confirmed the abnormal neural behavior of zebrafish larvae. Besides, the immune system has produced a large number of differentially expressed genes related to neural regulation. Inflammatory factor IL1β and IL-17 signaling pathways highly respond to MEHP, indicating that inflammation caused by immune system imbalance is a potential mechanism of MEHP-induced neurotoxicity. This study expands the understanding of the toxicity and molecular mechanisms of MEHP, providing a new perspective for in-depth neurotoxicity exploration of similar compounds.

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.

Exposure to polystyrene particles causes anxiety-, depression-like behavior and abnormal social behavior in mice

In the era of plastic use, organisms are constantly exposed to polystyrene particles (PS-Ps). PS-Ps accumulated in living organisms exert negative effects on the body, although studies evaluating their effects on brain development are scarce. In this study, the effects of PS-Ps on nervous system development were investigated using cultured primary cortical neurons and mice exposed to PS-Ps at different stages of brain development. The gene expression associated with brain development was downregulated in embryonic brains following PS-Ps exposure, and Gabra2 expression decreased in the embryonic and adult mice exposed to PS-Ps. Additionally, offspring of PS-Ps-treated dams exhibited signs of anxiety- and depression-like behavior, and abnormal social behavior. We propose that PS-Ps accumulation in the brain disrupts brain development and behavior in mice. This study provides novel information regarding PS-Ps toxicity and its harmful effects on neural development and behavior in mammals.

DNA Hypomethylation Is Associated with Increased Inflammation in Peripheral Blood Neutrophils of Children with Autism Spectrum Disorder: Understanding the Role of Ubiquitous Pollutant Di(2-ethylhexyl) Phthalate

Autism spectrum disorder (ASD) is a multidimensional disorder in which environmental, immune, and genetic factors act in concert to play a crucial role. ASD is characterized by social interaction/communication impairments and stereotypical behavioral patterns. Epigenetic modifications are known to regulate genetic expression through various mechanisms. One such mechanism is DNA methylation, which is regulated by DNA methyltransferases (DNMTs). DNMT transfers methyl groups onto the fifth carbon atom of the cytosine nucleotide, thus converting it into 5-methylcytosine (5mC) in the promoter region of the DNA. Disruptions in methylation patterns of DNA are usually associated with modulation of genetic expression. Environmental pollutants such as the plasticizer Di(2-ethylhexyl) phthalate (DEHP) have been reported to affect epigenetic mechanisms; however, whether DEHP modulates DNMT1 expression, DNA methylation, and inflammatory mediators in the neutrophils of ASD subjects has not previously been investigated. Hence, this investigation focused on the role of DNMT1 and overall DNA methylation in relation to inflammatory mediators (CCR2, MCP-1) in the neutrophils of children with ASD and typically developing healthy children (TDC). Further, the effect of DEHP on overall DNA methylation, DNMT1, CCR2, and MCP-1 in the neutrophils was explored. Our results show that the neutrophils of ASD subjects have diminished DNMT1 expression, which is associated with hypomethylation of DNA and increased inflammatory mediators such as CCR2 and MCP-1. DEHP further causes downregulation of DNMT1 expression in the neutrophils of ASD subjects, probably through oxidative inflammation, as antioxidant treatment led to reversal of a DEHP-induced reduction in DNMT1. These data highlight the importance of the environmental pollutant DEHP in the modification of epigenetic machinery such as DNA methylation in the neutrophils of ASD subjects.

Polysaccharide of Atractylodes macrocephala Koidz(PAMK) protects against DEHP-induced apoptosis in grass carp hepatocytes

Di(2-ethylhexyl) phthalate (DEHP) is a new environmental pollutant, which is widely used in plastic additives. DEHP and its metabolites pollute surface water and threaten the survival of fish. In order to investigate the mechanism of DEHP-induced apoptosis on grass carp hepatocytes, we treated grass carp hepatocytes with DEHP, and selected Atractylodes macrocephala Koidz (PAMK) to study its inhibitory effect on DEHP. The results showed that after DEHP exposure, apoptosis related proteins expression were increased significantly, leading to hepatocytes apoptosis. Moreover, AO/EB staining and Hoechst staining also showed that the number of apoptotic cells increased after DEHP exposure. It should be noted that PAMK simultaneous treatment could alleviate apoptosis induced by DEHP. The innovation of this study is that the application of Chinese herbal medicine (PAMK) to antagonize the damage of DEHP in fish was investigated for the first time. This study indicated that traditional Chinese medicine can also be used in fish production to reduce the accumulation of food-derived drugs.

An insight into sex-specific neurotoxicity and molecular mechanisms of DEHP: A critical review

Di-2-Ethylhexyl Phthalate (DEHP) is often used as an additive in polyvinyl chloride (PVC) to give plastics flexibility, which makes DEHP widely used in food packaging, daily necessities, medical equipment, and other products. However, due to the unstable combination of DEHP and polymer, it will migrate to the environment in the materials and eventually contact the human body. It has been recorded that low-dose DEHP will increase neurotoxicity in the nervous system, and the human health effects of DEHP have been paid attention to because of the extensive exposure to DEHP and its high absorption during brain development. In this study, we review the evidence that DEHP exposure is associated with neurodevelopmental abnormalities and neurological diseases based on human epidemiological and animal behavioral studies. Besides, we also summarized the oxidative damage, apoptosis, and signal transduction disorder related to neurobehavioral abnormalities and nerve injury, and described the potential mechanisms of neurotoxicity caused by DEHP. Overall, we found exposure to DEHP during the critical developmental period will increase the risk of neurobehavioral abnormalities, depression, and autism spectrum disorders. This effect is sex-specific and will continue to adulthood and even have an intergenerational effect. However, the research results on the sex-dependence of DEHP neurotoxicity are inconsistent, and there is a lack of systematic mechanisms research as theoretical support. Future investigations need to be carried out in a large-scale population and model organisms to produce more consistent and convincing results. And we emphasize the importance of mechanism research, which can enhance the understanding of the environmental and human health risks of DEHP exposure.

Exploring associations between urine levels of phthalates and autism spectrum disorder symptoms: a case-control study in Tianjin, China

Autism spectrum disorder (ASD) comprises a group of neurodevelopmental disorders. The etiology of autism remains unclear, but a growing body of evidence indicates that phthalates play a role in its pathogenesis. The aim of this study was to compare the urine levels of phthalates in children with ASD and healthy children. We also explored whether phthalates have an effect on ASD symptoms. The participants in this study included 101 children with ASD (79 boys and 22 girls) and 101 sex- and age-matched controls. The levels of phthalates were analyzed by gas chromatography-mass spectrometry (GC-MS). We detected significant differences in monoethyl phthalate (MEP) levels between the severe ASD and control groups (p < 0.05). Mono-n-butyl phthalate (MBP) concentration was positively correlated with language skill impairment in ASD (β: 0.387, p = 0.041). MEP levels were associated with the CARS "Imitation" score in all children (OR: 1.470). MBP levels were associated with the "Nonverbal Communication" score among boys (OR: 1.233), and MEP levels were associated with the "Nonverbal Communication" score among girls (OR: 2.648). MEP levels were related to the CARS total score after adjustment for sex (β: 1.524, p = 0.047). Compared with the reference mono(2-ethylhexyl) phthalate (MEHP) group, children with ASD in the medium-exposure group had an OR of 3.370 for aggravating ASD severity. These results suggested that increased exposure to phthalates contributes to more ASD symptoms and that there are potentially sex-specific associations. These findings warrant further confirmation.

Di-2-ethylhexyl phthalate affects zinc metabolism and neurogenesis in the developing rat brain

We previously observed that developmental marginal zinc deficiency affects neurogenesis. Maternal phthalate exposure could disrupt fetal zinc homeostasis by triggering an acute phase response, causing maternal liver zinc retention that limits zinc availability to the fetus. Thus, we currently investigated whether exposure to di-2-ethylhexyl phthalate (DEHP) during gestation in rats alters fetal brain neurogenesis by impairing zinc homeostasis. Dams consumed an adequate (25 μg zinc/g diet) (C) or a marginal zinc deficient (MZD) (10 μg zinc/g diet) diet, without or with DEHP (300 mg/kg BW) (C + DEHP, MZD + DEHP) from embryonic day (E) 0 to E19. To evaluate neurogenesis we measured parameters of neural progenitor cells (NPC) proliferation and differentiation. Maternal exposure to DEHP and/or zinc deficiency lowered fetal brain cortical tissue (CT) zinc concentrations. Transcription factors involved in NPC proliferation (PAX6, SOX2, EMX1), differentiation (TBR2, TBR1) and mature neurons (NeuN) were lower in MZD, MZD + DEHP and C + DEHP than in C E19 brain CT, being the lowest in the MZD + DEHP group. VGLUT1 levels, a marker of glutamatergic neurons, showed a similar pattern. Levels of a marker of GABAergic neurons, GAD65, did not vary among groups. Phosphorylated ERK1/2 levels were reduced by both MZD and DEHP, and particularly in the MZD + DEHP group. MEHP-treated human neuroblastoma IMR-32 cells and E19 brains from DEHP-treated dams showed that the zinc-regulated phosphatase PP2A can be in part responsible for DEHP-mediated ERK1/2 downregulation and impaired neurogenesis. Overall, gestational exposure to DEHP caused secondary zinc deficiency and impaired neurogenesis. These harmful effects could have long-term consequences on the adult offspring brain structure and function.

Autism spectrum disorder-like behavior induced in rat offspring by perinatal exposure to di-(2-ethylhexyl) phthalate

Autism spectrum disorders (ASD), also known as childhood autism, is a common neurological developmental disorder. Although it is generally believed that genetic factors are a primary cause for ASD development, more and more studies show that an increasing number of ASD diagnoses are related to environmental exposure. Epidemiological studies indicated that perinatal exposure to endocrine disruptors might cause neurodevelopmental disorders in children. Di-(2-ethylhexyl) phthalate (DEHP) is widely used as a plasticizer in many products. To explore the neurodevelopmental effect induced by perinatal exposure to DEHP on rat offspring, and the potential mechanisms, female Wistar rats were exposed to 1, 10, and 100 mg/kg/day DEHP during pregnancy and lactation, while valproic acid (VPA) was used as a positive control. The behavior tests showed that rat pups exposed to VPA and 100 mg/kg/day DEHP were not good as those from the control group in both their socialability and social novelty. Expression of mTOR pathway-related components increased while the number of autophagosomes decreased in the brain tissue of the rat offspring exposed to 100 mg/kg/day DEHP. In addition, perinatal exposure to DEHP at all dosages decreased the level of autophagy proteins LC3II and Beclin1 in the brain tissue of rat pups. Our results indicated that perinatal DEHP exposure would induce ASD-like behavioral changes in rat offspring, which might be mediated by activation of the mTOR signaling pathway, and inhibition of autophagy in the brain.

Effects of Di-2-Ethylhexyl Phthalate on Central Nervous System Functions: A Narrative Review

BACKGROUND

Phthalates are widely used in the plastics industry. Di-2-Ethylhexyl Phthalate (DEHP) is one of the most important phthalate metabolites that disrupt the function of endocrine glands. Exposure to DEHP causes numerous effects on animals, humans, and the environment. Low doses of DEHP increase neurotoxicity in the nervous system that has arisen deep concerns due to the widespread nature of DEHP exposure and its high absorption during brain development.

OBJECTIVE

In this review article, we evaluated the impacts of DEHP exposure from birth to adulthood on neurobehavioral damages. Then, the possible mechanisms of DEHP-induced neurobehavioral impairment were discussed.

METHODOLOGY

Peer-reviewed articles were extracted through Embase, PubMed, and Google Scholar till the year 2021.

RESULTS

The results showed that exposure to DEHP during pregnancy and infancy leads to memory loss and irreversible nervous system damage.

CONCLUSION

Overall, it seems that increased levels of oxidative stress and inflammatory mediators possess a pivotal role in DEHP-induced neurobehavioral impairment.

Dysregulated Nrf2 signaling in response to di(2-ethylhexyl) phthalate in neutrophils of children with autism

Autism spectrum disorder (ASD) is characterized by constellation of impaired behaviors that include deficits in social interaction/communication and the presence of restricted/repetitive behavioral patterns. Both genetic component and environmental factors are thought to play a key role in the initiation and progression of ASD. Several environmental factors such as heavy metals and plasticizers are known to affect the progression of ASD. One of the most common pollutants in the environment today is di-2-ethylhexyl phthalate (DEHP). DEHP is utilized as a plasticizer in several household and office materials which range from medical devices to plastic toys. Children usually get exposed to DEHP at an early age through use of plastic toys and other plastic materials. Nuclear factor erythroid 2 (NFE2)-relatedfactor-2 (Nrf2) is a master redox regulator as it controls transcription of several antioxidant genes. DEHP has been reported to cause dysregulation in Nrf2 signaling in vitro/in vivo and ASD subjects also exhibit oxidant-antioxidant imbalance.Therefore, this study attempted to delineate the effect of DEHP on Nrf2 signaling in neutrophils of ASD and typically developing healthy children (TDC) in vitro. Our data display that neutrophils of ASD subjects have dysregulated Nrf2 and hemeoxygenase-1 (HO-1) expression as compared to TDC subjects. DEHP treatment leads to elevation of oxidant stress in neutrophils of both ASD and TDC subjects, however TDC neutrophils have better antioxidant response to mitigate oxidative stress. This is depicted by enhancement of Nrf2/HO-1 signaling in TDC neutrophils in response to DEHP whereas ASD neutrophils fail to do so. These results suggest that plasticizer, DEHP may cause further dysregulation in Nrf2 signaling which may promote progression of ASD.

Systematic review of prenatal exposure to endocrine disrupting chemicals and autism spectrum disorder in offspring

LAY ABSTRACT

Autism spectrum disorders comprise a complex group with many subtypes of behaviorally defined neurodevelopmental abnormalities in two core areas: deficits in social communication and fixated, restricted, repetitive, or stereotyped behaviors and interests each with potential unique risk factors and characteristics. The underlying mechanisms and the possible causes of autism spectrum disorder remain elusive and while increased prevalence is undoubtable, it is unclear if it is a reflection of diagnostic improvement or emerging risk factors such as endocrine disrupting chemicals. Epidemiological studies, which are used to study the relation between endocrine disrupting chemicals and autism spectrum disorder, can have inherent methodological challenges that limit the quality and strength of their findings. The objective of this work is to systematically review the treatment of these challenges and assess the quality and strength of the findings in the currently available literature. The overall quality and strength were "moderate" and "limited," respectively. Risk of bias due to the exclusion of potential confounding factors and the lack of accuracy of exposure assessment methods were the most prevalent. The omnipresence of endocrine disrupting chemicals and the biological plausibility of the association between prenatal exposure and later development of autism spectrum disorder highlight the need to carry out well-designed epidemiological studies that overcome the methodological challenges observed in the currently available literature in order to be able to inform public policy to prevent exposure to these potentially harmful chemicals and aid in the establishment of predictor variables to facilitate early diagnosis of autism spectrum disorder and improve long-term outcomes.

Prenatal exposure to di (2-ethylhexyl) phthalate causes autism-like behavior through inducing Nischarin expression in the mouse offspring

Epidemiologic evidence has suggested a relationship between di (2-ethylhexyl) phthalate (DEHP) prenatal exposure and autism spectrum disorders (ASD), but the underlying mechanisms are still at large unknown. In this study, pregnant mice were intragastrically administered with DEHP once a day from GD 3 to GD 17 and the neurobehavioral changes of offspring were evaluated. In addition to the repetitive stereotyped behaviors, DEHP at the concentration of 50 mg/kg/day and above significantly impaired the sociability of the offspring (P < 0.05) and decreased the density of dendritic spines of pyramidal neurons in the prefrontal cortex (P < 0.05). At the same time, the expression of Nischarin protein in prefrontal lobe increased (P < 0.05). Similarly, after 12-h incubation of DEHP at the concentration of 100 nM, the total spine density, especially the mushroom and stubby spine populations, significantly decreased in the primary cultured prefrontal cortical neurons (P < 0.05). However, the inhibitory effect of DEHP were reversed by knockdown of Nischarin expression. Collectively, these results suggest that prenatal DEHP exposure induces Nischarin expression, causes dendritic spine loss, and finally leads to autism-like behavior in mouse offspring.

Comparing Levels of Urinary Phthalate Metabolites in Egyptian Children with Autism Spectrum Disorders and Healthy Control Children: Referring to Sources of Phthalate Exposure

Background: Evidence supporting environmental risk factors of autism spectrum disorder (ASD) is rising. Phthalates are assumed to contribute to this risk due to their extensive use in daily life as plasticizers and additives in numerous customer products. Phthalates are also accused as a neurotoxic agent affecting brain development. Aim: The main objective of this study is to compare the concentrations of urinary phthalate metabolites as biomarkers of phthalate exposure in children with autism to that of a healthy control group and to compare their exposure to suspected environmental sources of phthalate. Methods: It was a case-control study; conducted over a period of one year. Thirty-eight children with ASD and 99 apparently healthy children comprised the control group, were enrolled in the study. Urinary concentrations of four phthalate metabolites were measured, using a combination of solid phase extraction, high pressure liquid chromatography, and tandem mass spectrometry. Results: Children with ASD comprised 38 children (32 boys and 6 girls), their mean age was 8.95 + 4.17 years. There were significant higher levels of urinary Mono (2ethylhexyl) phthalate (MEHP), mono benzyl, and mono butyl phthalates in cases vs. controls with p value equals (0.006, 0.017 and <0.001) respectively. Regression analysis revealed that male gender and the level of mono butyl are the main predictors of ASD (p<0.001). Conclusion: This study suggested a link between phthalates and ASD with higher urinary levels of phthalate metabolites in children with ASD. These high levels are either due to increased exposure or defective metabolism in children with ASD. The study declined any relationship of the studied sources of phthalate exposure to ASD except the exposure to wall painting with plastic.

Association of phthalate exposure with autistic traits in children

BACKGROUND

Phthalates are synthetic chemicals with endocrine-disrupting properties. They are reportedly associated with various neurotoxic outcomes. Studies on exposure to phthalates and children's autistic traits have shown inconsistent results with respect to sex and susceptible time periods. We investigated the association of phthalate exposure during the prenatal period and childhood with autistic traits over time using a birth cohort in South Korea.

METHODS

Five phthalate metabolites were measured during mid-term pregnancy and children's follow-up at ages of 4, 6, and 8 years among a total of 547 mother-child pairs. The social communication questionnaire (SCQ) was used to assess autistic traits of children at each time point. The relationship between phthalate metabolites and SCQ scores were analyzed by exposure windows and sex.

RESULTS

A 2.7 fold increase in di-(2-ethylhexyl) phthalate metabolite levels, mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) during pregnancy was associated with increased SCQ scores at 4 years by 8.5% (95% confidence intervals [CI]: 1.9%, 15.5%) and 7.4% (95% CI: 0.3%, 15.0%), respectively, but not at the age of 6 or 8 years. Moreover, MEHHP levels at ages of 4 and 8 years were associated with increased SCQ scores at 8 years by 9.9% (95% CI: 1.8%, 18.6%) and 9.6% (95% CI: 1.3%, 18.6%), respectively. Boys showed stronger associations between phthalate exposure and SCQ scores than girls.

CONCLUSION

The study suggested different susceptible time windows of phthalate exposure: exposure during pregnancy is associated with autistic traits in young children, whereas exposure during early childhood years leads to autistic traits in school-aged children, particularly boys.

Abnormal dendritic morphology in the cerebellum of cyclooxygenase-2- knockin mice

Prostaglandin E2 (PGE2) is a bioactive signalling molecule metabolized from the phospholipid membranes by the enzymatic activity of cycloxygenase-2 (COX-2). In the developing brain, COX-2 constitutively regulates the production of PGE2, which is important in neuronal development. However, abnormal COX-2/PGE2 signalling has been linked to neurodevelopmental disorders including autism spectrum disorders (ASDs). We have previously demonstrated that COX-2^- -KI mice show autism-related behaviours including social deficits, repetitive behaviours and anxious behaviours. COX-2-deficient mice also have deficits in pathways involved in synaptic transmission and dendritic spine formation. In this study, we use a Golgi-COX staining method to examine sex-dependent differences in dendritic and dendritic spine morphology in neurons of COX-2^- -KI mice cerebellum compared with wild-type (WT) matched controls at postnatal day 25 (P25). We show that COX-2^- -KI mice have increased dendritic arborization closer to the cell soma and increased dendritic looping. We also observed a sex-dependent effect of the COX-2^- -KI on dendritic thickness, dendritic spine density, dendritic spine morphology, and the expression of β-actin and the actin-binding protein spinophilin. Our findings show that changes in COX-2/PGE2 signalling lead to impaired morphology of dendrites and dendritic spines in a sex-dependant manner and may contribute the pathology of the cerebellum seen in individuals with ASD. This study provides further evidence that the COX-2^- -KI mouse model can be used to study a subset of ASD pathologies.

Association Between Gestational Exposure to Toxicants and Autistic Behaviors Using Bayesian Quantile Regression

Autism spectrum disorder, which is characterized by impaired social communication and stereotypic behaviors, affects 1%-2% of children. Although prenatal exposure to toxicants has been associated with autistic behaviors, most studies have been focused on shifts in mean behavior scores. We used Bayesian quantile regression to assess the associations between log2-transformed toxicant concentrations and autistic behaviors across the distribution of behaviors. We used data from the Maternal-Infant Research on Environmental Chemicals study, a pan-Canadian cohort (2008-2011). We measured metal, pesticide, polychlorinated biphenyl, phthalate, bisphenol-A, and triclosan concentrations in blood or urine samples collected during the first trimester of pregnancy. Using the Social Responsiveness Scale (SRS), in which higher scores denote more autistic-like behaviors, autistic behaviors were assessed in 478 children aged 3-4 years old. Lead, cadmium, and most phthalate metabolites were associated with mild increases in SRS scores at the 90th percentile of the SRS distribution. Manganese and some pesticides were associated with mild decreases in SRS scores at the 90th percentile of the SRS distribution. We identified several monotonic trends in which associations increased in magnitude from the bottom to the top of the SRS distribution. These results suggest that quantile regression can reveal nuanced relationships and, thus, should be more widely used by epidemiologists.

Bioaccumulation and health risk assessment of phthalate esters in cultured low trophic level fish feded with food waste-based diets

The present study aimed at using different types of food waste as a protein source for the fish feeds to produce safe and quality fish. The results showed the concentrations of ∑PAEs in grass crap (0.24 μg g^-1 ww) and bighead carp (0.15 μg g^-1 ww) fed with Food waste B feeds (mainly containing fruit, vegetable and cereal waste) was significantly lower than those fed Food waste A feeds (mainly containing meat waste) and control feeds (p<0.05), and the highest ∑PAEs concentration (1.75 μg g^-1 ww) was found in the mud carp fed with control feeds in experimental ponds (p<0.05). In addition, there was no biomagnification of PAEs in the food chains within the ponds. The health risk assessment results showed no non-carcinogenic and carcinogenic risks from the PAEs via ingestion of the fish fed with food waste feeds for the local residents.

Exposure to the plasticizer, Di-(2-ethylhexyl) phthalate during juvenile period exacerbates autism-like behavior in adult BTBR T + tf/J mice due to DNA hypomethylation and enhanced inflammation in brain and systemic immune cells

Epigenetic modifications are known to play a crucial role in the behavioral modifications through regulation of gene expression. Environmental factors are known to regulate genetic transcription through DNA methylation which is one of the mechanisms of epigenetic modification. Di-2-ethylhexyl phthalate (DEHP) is one of the most abundant phthalate plasticizers in day-to-day products. Prenatal/postnatal DEHP administration has been reported to cause inflammation as well as behavioral dysregulation, however it is not known if exposure to DEHP during juvenile stage affects peripheral/neuronal inflammation and autism-like symptoms in BTBR mice at adulthood. This study investigated effect of DEHP exposure during juvenile period on DNA methylation (global DNA methylation/DNMT1 expression) and inflammation (IL-17A, IL-6, MCP-1, TNF-α) in CD4 + T cells/CD11c + DCs and cortex, and autism-like symptoms (three-chambered sociability test, self-grooming and marble burying test) in asocial BTBR and social C57 mice at adulthood. Our data reveal that BTBR mice exposed to DEHP during juvenile period have hypomethylated DNA/DNMT1 expression in CD11c + DCs and cortex as compared to vehicle-exposed BTBR mice. It was associated with upregulated inflammation in periphery [plasma IL-6/IL-17A, CD11c + DCs (IL-6/MCP-1/TNF-α), and CD4+ T cells (IL-17A)] and cortex (IL-6, MCP-1, TNF-α), and aggravation in autism-like symptoms in DEHP-treated BTBR mice. These data propose that exposure of DEHP during juvenile period may affect autism-like behavior and inflammation in BTBR mice at adulthood through epigenetic regulation. Therefore, underlying genetic predisposition may play a crucial role in worsening of autistic symptoms in ASD subjects in adulthood if they are exposed to environmental pollutants such as DEHP during juvenile period.

Biotechnology-based microbial degradation of plastic additives

Plastic additives are agents responsible to the flame resistance, durability, microbial resistance, and flexibility of plastic products. High demand for production and use of plastic additives is associated with environmental accumulation and various health hazards. One of the suitable methods of depleting plastic additive in the environment is bioremediation as it offers cost-efficiency, convenience, and sustainability. Microbial activity is one of the effective ways of detoxifying various compounds as microorganisms can adapt in an environment with high prevalence of pollutants. The present review discusses the use and abundance of these plastic additives, their health-related risks, the microorganisms capable of degrading them, the proposed mechanism of biodegradation, and current innovations capable of improving the efficiency of bioremediation.

An integrative toxicogenomic analysis of plastic additives

In developed countries, contact with plastics is constant. Plastics contain a vast number of additives such as plasticisers, stabilisers, antioxidants, flame retardants, etc., that can impact human health. Most of them have been studied separately; however, an integrative approach to identify genes, biological processes, molecular functions, and diseases linked to exposure to these compounds has not been addressed until now. The genes most commonly affected by plastic additives are related to apoptosis, cell death, proliferation and differentiation, immunity and insulin-related processes, and are mainly associated with cancer, mental disorders, diabetes mellitus type II and obesity. The most commonly affected molecular functions included steroid hormone receptor activity implicated in cancer, mental disorders, immune signalling and gonadotropin-releasing hormones. These processes and functions affected by plastic additives are related to the diseases of the developed world, most of which are linked to the endocrine system, such as cancer, diabetes, infertility and obesity. The strong interconnection among the top 50 genes modulated by plastic additives shows that the pathways affected are strongly interrelated. Therefore, studying the effects of plastic additives through a single-compound approach cannot be sufficient and a holistic approach is more appropriate for evaluating the potential effects of plastics in human health.

Moringa oleifera Protects SH-SY5YCells from DEHP-Induced Endoplasmic Reticulum Stress and Apoptosis

Moringa oleifera (MO) is a medicinal plant that has been shown to possess antioxidant, anticarcinogenic and antibiotic activities. In a rat model, MO extract (MOe) has been shown to have a protective effect against brain damage and memory decline. As an extending study, here, we have examined the protective effect of MOe against oxidative stress and apoptosis caused in human neuroblastome (SH-SY5Y) cells by di-(2-ethylhexyl) phthalate (DEHP), a plasticizer known to induce neurotoxicity. Our data show that MOe prevents oxidative damage by lowering reactive oxygen species (ROS) formation, restoring mitochondrial respiratory chain complex activities, and, in addition, by modulating the expression of vitagenes, i.e., antioxidant proteins Nrf2 and HO-1. Moreover, MOe prevented neuronal damage by partly inhibiting endoplasmic reticulum (ER) stress response, as indicated by decreased expression of CCAAT-enhancer-binding protein homologous protein (CHOP) and Glucose-regulated protein 78 (GRP78) proteins. MOe also protected SH-SY5Y cells from DEHP-induced apoptosis, preserving mitochondrial membrane permeability and caspase-3 activation. Our findings provide insight into understanding of molecular mechanisms involved in neuroprotective effects by MOe against DEHP damage.

Aggravation of autism-like behavior in BTBR T+tf/J mice by environmental pollutant, di-(2-ethylhexyl) phthalate: Role of nuclear factor erythroid 2-related factor 2 and oxidative enzymes in innate immune cells and cerebellum

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder which manifests itself in early childhood and is distinguished by recurring behavioral patterns, and dysfunction in social/communication skills. Ubiquitous environmental pollutant, di-2-ethylhexyl phthalate (DEHP) is one of the most frequently used plasticizers in various industrial products, e.g. vinyl flooring, plastic toys, and medical appliances. DEHP gets easily released into the environment and leads to human exposure through various routes. DEHP has been described to be linked with oxidative stress in various organs in animal/human studies. Increased concentration of DEHP has also been detected in ASD children which indicates an association between phthalates exposure and ASD. However, effect of DEHP on autism-like behavior has not been investigated previously. Therefore, this study probed the effect of DEHP on autism-like behavior (marble burying, self-grooming and sociability) and innate immune cells (dendritic cells/neutrophils)/cerebellar oxidant-antioxidant balance (NFkB, iNOS, NADPH oxidase, nitrotyrosine, lipid peroxides, Nrf2, SOD, GPx) in BTBR and C57 mice. Our data show that DEHP treatment causes worsening of autism-like behavior in BTBR mice which is associated with enhancement of oxidative stress in innate immune cells and cerebellum with concomitant lack of antioxidant protection. DEHP also causes oxidative stress in C57 mice in both innate immune cells and cerebellar compartment, however there is Nrf2-mediated induction of enzymatic antioxidants which protects them from upregulated oxidative stress. This proposes the notion that ubiquitous environmental pollutants such as DEHP may be involved in the pathogenesis/progression of ASD through dysregulation of antioxidant-antioxidant balance in innate immune cells and cerebellum.

Co-exposure to polycyclic aromatic hydrocarbons and phthalates and their associations with oxidative stress damage in school children from South China

Monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs), phthalate metabolites (mPAEs), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in the urine of school children aged 8-11 years from Shenzhen, China were measured in order to investigate oxidative stress damage from co-exposure to PAHs and PAEs. The concentrations of OH-PAHs and mPAEs in urine were 0.36-36.5 (median: 3.86) and 9.48-1609 (median: 240) ng/mL respectively. Gender and age did not influence urinary concentrations of ΣOH-PAHs and ΣmPAEs, but geographical variations (i.e., urban versus suburban) were observed. Levels of 8-OHdG were positively correlated with urinary OH-PAHs and mPAEs, with correlation coefficients (r) varying between 0.160 and 0.365 (p < 0.05). OH-PAHs made a greater contribution to oxidative DNA damage than mPAEs when these two types of pollutants were present at the same concentrations. Human health risks were assessed using the hazard quotient and the hazard index for the cumulative risk of a complex of chemicals. The results demonstrated that risks from PAHs could be neglected, but that 29.5 % of school children may be subject to obvious health risks from PAEs, especially diethylhexyl phthalate.

Molecules, Mechanisms, and Disorders of Self-Domestication: Keys for Understanding Emotional and Social Communication from an Evolutionary Perspective

The neural crest hypothesis states that the phenotypic features of the domestication syndrome are due to a reduced number or disruption of neural crest cells (NCCs) migration, as these cells differentiate at their final destinations and proliferate into different tissues whose activity is reduced by domestication. Comparing the phenotypic characteristics of modern and prehistoric man, it is clear that during their recent evolutionary past, humans also went through a process of self-domestication with a simultaneous prolongation of the period of socialization. This has led to the development of social abilities and skills, especially language, as well as neoteny. Disorders of neural crest cell development and migration lead to many different conditions such as Waardenburg syndrome, Hirschsprung disease, fetal alcohol syndrome, DiGeorge and Treacher-Collins syndrome, for which the mechanisms are already relatively well-known. However, for others, such as Williams-Beuren syndrome and schizophrenia that have the characteristics of hyperdomestication, and autism spectrum disorders, and 7dupASD syndrome that have the characteristics of hypodomestication, much less is known. Thus, deciphering the biological determinants of disordered self-domestication has great potential for elucidating the normal and disturbed ontogenesis of humans, as well as for the understanding of evolution of mammals in general.

Linking emerging contaminants exposure to adverse health effects: Crosstalk between epigenome and environment

Environmental epigenetic findings shed new light on the roles of epigenetic regulations in environmental exposure-induced toxicities or disease susceptibilities. Currently, environmental emerging contaminants (ECs) are in focus for further investigation due to the evidence of human exposure in addition to their environmental occurrences. However, the adverse effects of these environmental ECs on health through epigenetic mechanisms are still poorly addressed in many aspects. This review discusses the epigenetic mechanisms (DNA methylation, histone modifications, and microRNA expressions) linking ECs exposure to health outcomes. We emphasized on the recent literature describing how ECs can dysregulate epigenetic mechanisms and lead to downstream health outcomes. These up-to-date research outputs could provide novel insights into the toxicological mechanisms of ECs. However, the field still faces a demand for further studies on the broad spectrum of health effects, synergistic/antagonistic effects, transgenerational epigenetic effects, and epidemiologic and demographic data of ECs.

Ubiquitous plasticizer, Di-(2-ethylhexyl) phthalate enhances existing inflammatory profile in monocytes of children with autism

Genetic as well as environmental factors are believed to play a significant role in the pathogenesis and progression of autism spectrum disorder (ASD). Phthalates are ubiquitous environmental contaminants as they are used plasticizers in several household/industrial products such as vinyl flooring, plastic toys, and cosmetic products. One of the plasticizers that is quite prevalent in these products is di-2-ethylhexyl phthalate (DEHP) which can cause human exposure via dermal/inhalation/ingestion routes. DEHP and its metabolites are associated with behavioral dysregulations and reported to be increased in systemic circulation of ASD children. DEHP is reported to cause upregulation of several inflammatory cytokines in different cells/tissues, however its role in inflammatory signaling of ASD monocytes has not been investigated earlier. Therefore, this study evaluated the effects of DEHP (at 5 μM final concentration for 24 h) on inflammatory profile (NFkB, STAT3, IL-6, TNF-α, IL-1β) in monocytes of ASD subjects and typically developing control (TDC) children. Our data show that DEHP upregulates NFkB/STAT3 expression which is associated with increased inflammatory profile in monocytes of ASD and TDC subjects, however its effect is much greater in magnitude in the former group. This was confirmed by utilization of NFkB inhibitor, PDTC and STAT3 inhibitor, Stattic which caused reduction in inflammatory cytokines from DEHP-treated monocytes in ASD group. In short, DEHP causes further elevation in inflammatory signaling in ASD monocytes which could be due to existing inflammation in this group. These data suggest that use of plasticizers such as DEHP should be minimized in order to avoid their potential effects on immune dysfunction associated with ASD.

Gut microbiota dysbiosis might be responsible to different toxicity caused by Di-(2-ethylhexyl) phthalate exposure in murine rodents

Di-(2-ethylhexyl) phthalate (DEHP) is widely used as a plasticizer, which can enter the body through a variety of ways and exerted multiple harmful effects, including liver toxicity, reproductive toxicity and even glucose metabolism disorder. Many studies have suggested that changes of gut microbiota are closely related to the occurrence of various diseases, but the effects of DEHP exposure on gut microbiota are still unclear. It was found in this study that the damage to different tissues by DEHP on two strains each from two different species of male rodents before puberty was dose and time of exposure dependent, and also depending on the strain and species of rodent. Sprague-Dawley (SD) rats showed highest sensitivity to DEHP exposure, with most severe organ damage, highest Th1 inflammatory response and most significant body weight gain. Correspondingly, the gut microbiota of SD rats showed most significant changes after DEHP exposure. Only SD rats, but not Wistar rats, BALB/c and C57BL/6J mice showed an increase in Firmicutes/Bacteroidetes ratio and Proteobacteria abundance in the fecal samples, which are known to associate with obesity and diabetes. This is consistent with the increasing body weight gain which was only found in SD rats. In addition, the decrease in the level of butyrate, increase in the abundance of potential pathogens and microbial genes linked to colorectal cancer, Parkinson's disease, and type 2 diabetes in the SD rats were associated with issue and functional damages and Th1 inflammatory response caused by DEHP exposure. We postulate that the differential effects of DEHP on gut microbiota may be an important cause of the differences in the toxicity on different strains and species of rodents to DEHP.

Prenatal phthalate exposure, oxidative stress-related genetic vulnerability and early life neurodevelopment: A birth cohort study

Prenatal phthalate chemicals may have adverse effects on brain development by various mechanisms including oxidant damage. However, birth cohort findings have been conflicting. This study aimed to (i) investigate the interplay between maternal prenatal phthalate levels, infant genetic vulnerability to oxidative stress, and child neurodevelopment and (ii) examine combined putative oxidant exposures. In a population-based birth cohort of 1064 women with prenatal recruitment in Victoria, Australia, maternal urine was collected at 36 weeks of pregnancy and phthalate metabolite concentrations measured. An unweighted genetic score for oxidative stress was made using a candidate gene approach. Cognition was assessed using the BAYLEY-III at two years (n = 678). Parents completed questionnaires for doctor diagnosed autism spectrum disorder (ASD) (1.4 %), ASD traits (4.9 %) and child inattention/hyperactivity (n = 791). Analyses included multiple linear and logistic regression. Higher prenatal phthalate levels and a higher oxidative stress genetic score were each associated with subsequent ASD. Several oxidative stress-related SNPs modified the association between prenatal phthalates and ASD and other outcomes. Consistent patterns were evident across gene score-phthalate combinations for cognition, ASD, ASD traits and inattention/hyperactivity. Other putative oxidant factors such as prenatal smoking further increased risk. Prenatal phthalate levels and infant oxidative stress-related genetic vulnerability are associated with adverse neurodevelopment. Combined exposures are important. Current recommendations and regulation on maternal phthalate exposure during pregnancy require re-evaluation.

Phthalate exposure and neurodevelopment: A systematic review and meta-analysis of human epidemiological evidence

OBJECTIVE

We performed a systematic review of the epidemiology literature to identify the neurodevelopmental effects associated with phthalate exposure.

DATA SOURCES AND STUDY ELIGIBILITY CRITERIA

Six phthalates were included in the review: di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), butyl benzyl phthalate (BBP), and diethyl phthalate (DEP). The initial literature search (of PubMed, Web of Science, and Toxline) included all studies of neurodevelopmental effects in humans, and outcomes were selected for full systematic review based on data availability.

STUDY EVALUATION AND SYNTHESIS METHODS

Studies of neurodevelopmental effects were evaluated using criteria defined a priori for risk of bias and sensitivity by two reviewers using a domain-based approach. Evidence was synthesized by outcome and phthalate and strength of evidence was summarized using a structured framework. For studies of cognition and motor effects in children ≤4 years old, a random effects meta-analysis was performed.

RESULTS

The primary outcomes reviewed here are (number of studies in parentheses): cognition (14), motor effects (9), behavior, including attention deficit hyperactivity disorder (20), infant behavior (3), and social behavior, including autism spectrum disorder (7). For each phthalate/outcome combination, there was slight or indeterminate evidence of an association, with the exception of motor effects for BBP, which had moderate evidence.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Overall, there is not a clear pattern of association between prenatal phthalate exposures and neurodevelopment. There are several possible reasons for the observed null associations related to exposure misclassification, periods of heightened susceptibility, sex-specific effects, and the effects of phthalate mixtures. Until these limitations are adequately addressed in the epidemiology literature, these findings should not be interpreted as evidence that there are no neurodevelopmental effects of phthalate exposure. The views expressed are those of the authors and do not necessarily represent the views or policies of the U.S. EPA.

Knockdown of TNFAIP1 prevents di-(2-ethylhexyl) phthalate-induced neurotoxicity by activating CREB pathway

Di-(2-ethylhexyl) phthalate (DEHP) is a widely used plasticizer. It has neurotoxicity and exposure to it causes impairment of neurodevelopment, behavior and cognition. However, the molecular mechanisms responsible for the DEHP-induced neurotoxicity are not yet clearly defined. Tumor necrosis factor-induced protein 1 (TNFAIP1) was first discovered in umbilical vein endothelial cells and was further found to be important in the progress of Alzheimer's disease. Herein we explore the mechanism of TNFAIP1 in DEHP-induced neurotoxicity with the involvement of cyclic AMP response elements binding protein (CREB) signaling pathway in a mouse neuroblastoma cell line (N2a cells). We found that exposure to DEHP induced apoptosis and downregulated the expression of brain-derived neurotrophic factor (BDNF), synaptic proteins PSD 95 and synapsin-1 while upregulated the expression of TNFAIP1 and decreased the levels of phosphorylated Akt, CaMK Ⅳ, catalytic subunits of PKA and CREB in CREB signaling pathway. Knockdown of TNFAIP1 using TNFAIP1 small interfering RNA (siRNA) expression vector prevented DEHP from inhibiting CREB pathway, thus reduced apoptosis and restored expression of BDNF, PSD 95 and synapsin-1. Our data indicate that downregulation of TNFAIP1 prevents DEHP-induced neurotoxicity via activating CREB pathway. Therefore, TNFAIP1 is a potential target for relieving the DEHP-induced neurotoxicity and related neurological disorders.

Sources of clinically significant neonatal intensive care unit phthalate exposure

In the United States each year, more than 300,000 infants are admitted to neonatal intensive care units (NICU) where they are exposed to a chemical-intensive hospital environment during a developmentally vulnerable period. Although multiple studies have demonstrated elevated phthalate biomarkers in NICU patients, specific sources of NICU-based phthalate exposure have not been identified.In this study, premature newborns with birth weight <1500 g were recruited to participate in a prospective environmental health cohort during the NICU hospitalization. Exposure to specific NICU equipment was recorded daily during the NICU hospitalization. One hundred forty-nine urine specimens from 71 infants were analyzed for phthalate metabolites using high-performance liquid chromatography/tandem mass spectrometry.In initial analyses, exposure to medical equipment was directly related to phthalate levels, with DEHP biomarkers 95-132% higher for infants exposed to specific medical equipment types compared to those without that equipment exposure (p < 0.001-0.023). This association was mirrored for clinically relevant phthalate mixtures whether composed of DEHP metabolites or not (p = 0.002-0.007). In models accounting for concurrent equipment use, exposure to respiratory support was associated with DEHP biomarkers 50-136% higher in exposed compared to unexposed infants (p = 0.007-0.036). Phthalate mixtures clinically relevant to neurobehavioral development were significantly associated with non-invasive respiratory support (p = 0.008-0.026). Feeding supplies and intravenous lines were not significantly associated with clinically important phthalate mixtures.Respiratory support equipment may be a significant and clinically relevant NICU source of phthalate exposure. Although manufacturers have altered feeding and intravenous supplies to reduce DEHP exposure, other sources of exposure to common and clinically impactful phthalates persist in the NICU.

Autistic feature as a presentation of Inborn Errors of Metabolism

Autism spectrum disorder (ASD) is a category of neurodevelopmental disorders characterized by social and communication impairment and restricted or repetitive behaviors. The pathogenesis of ASD is not well understood and it's proved that genetic is strongly associated with ASD in 5 to 25% of cases. Inborn errors of metabolism(IEMs), defined by a vast array of disorders that are caused by specific enzyme deficiencies or transport protein defects, is as frequent as in 1 in 800 births. IEMs can manifest several psychiatric or behavioral manifestations such as self-injuriesincreased activity and aggression, personality changes, paranoia, depression, catatonia, and psychosis. IEMs underlie autistic symptoms in less than 5% of cases. The literature on the association between ASD and respiratory chain abnormalities is growing, including complex III/IV deficiency and MELAS (mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes) syndrome, as well as glucose-6-phosphate dehydrogenase deficiency. Google Scholar, Pubmed, and SCOPUS databases were searched using a combination of the following keywords: "autism spectrum disorder", "autism spectrum", "autistic feature" and "inborn error of metabolism", " IEM", "congenital error of metabolism". Initially, 655 articles were found and our expert and methodologist altogether selected 187 articles based on the titles, relevance, and text language. After reading full texts, 37 studies were selected for review. We think it's best to consider IEMs in children with syndromic ASD and/or if there is a strong familial history of autism or parental consanguineous marriage.

Biomarkers for Autism Spectrum Disorders (ASD): A Meta-analysis

OBJECTIVE

To compare the reported accuracy and sensitivity of the various modalities used to diagnose autism spectrum disorders (ASD) in efforts to help focus further biomarker research on the most promising methods for early diagnosis.

METHODS

The Medline scientific literature database was searched to identify publications assessing potential clinical ASD biomarkers. Reports were categorized by the modality used to assess the putative markers, including protein, genetic, metabolic, or objective imaging methods. The reported sensitivity, specificity, area under the curve, and overall agreement were summarized and analyzed to determine weighted averages for each diagnostic modality. Heterogeneity was measured using the I² test.

RESULTS

Of the 71 papers included in this analysis, each belonging to one of five modalities, protein-based followed by metabolite-based markers provided the highest diagnostic accuracy, each with a pooled overall agreement of 83.3% and respective weighted area under the curve (AUC) of 89.5% and 88.3%. Sensitivity provided by protein markers was highest (85.5%), while metabolic (85.9%) and protein markers (84.7%) had the highest specificity. Other modalities showed degrees of sensitivity, specificity, and overall agreements in the range of 73%-80%.

CONCLUSIONS

Each modality provided for diagnostic accuracy and specificity similar or slightly higher than those reported for the gold-standard Autism Diagnostic Observation Schedule (ADOS) instrument. Further studies are required to identify the most predictive markers within each modality and to evaluate biological pathways or clustering with possible etiological relevance. Analyses will also be necessary to determine the potential of these novel biomarkers in diagnosing pediatric patients, thereby enabling early intervention.

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.

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.

DEHP toxicity on vision, neuromuscular junction, and courtship behaviors of Drosophila

Bis(2-ethylhexyl) phthalate (DEHP) is the most common plasticizer. Previous studies have shown DEHP treatment accelerates neurological degeneration, suggesting that DEHP may impact retinal sensitivity to light, neurotransmission, and copulation behaviors. Although its neurotoxicity and antifertility properties have been studied, whether DEHP exposure disrupts vision and how DEHP influences neuromuscular junction (NMJ) have not been reported yet. Moreover, the impact of DEHP on insect courtship behavior is still elusive. Fruit flies (Drosophila melanogaster) were treated with series concentrations of DEHP and observed for lifespan, motor function, electroretinogram (ERG), electrophysiology of neuromuscular junction (NMJ), courtship behaviors, and relevant gene expression. Our results confirmed the DEHP toxicity on lifespan and capacity of motor function and updated its effect on copulation behaviors. Additionally, we report for the first time that DEHP exposure may harm vision by affecting the synaptic signaling between the photoreceptor and the laminar neurons. Further, DEHP treatment altered both spontaneous and evoked neurotransmission properties. Noteworthy, the effect of DEHP exposure on the copulation behavior is sex-dependent, and we proposed potential mechanisms for future investigation.

Temporal Trends of Urinary Phthalate Concentrations in Two Populations: Effects of REACH Authorization after Five Years

Phthalates are widely used in the industrial manufacture of many products. Some phthalates have shown reproductive toxicity in humans, acting as endocrine disruptors, so they were included in the authorization process defined in Reg. CE 1907/2006 (REACH). Two groups of population were recruited, before and after the inclusion of some phthalates in the authorization list in REACH: the first group of 157 volunteers was studied in 2011 and the second, 171 volunteers, in 2016. Each subject completed a questionnaire about personal lifestyle, working activities and use of chemical products. The main urinary metabolites of five phthalates were analyzed by HPLC/MS/MS: mono(2-ethylhexyl)phthalate (MEHP) and mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) for di(2-ethylhexyl)phthalate (DEHP) exposure; monoethylphthalate (MEP) for diethylphtahate (DEP); monobenzylphthalate (MBzP) for butylbenzylphtahalate (BBP) and dibenzylphthalate (DBzP), mono-n-butylphthalate (MnBP) for butylbenzylphtahalate (BBP) and di-n-butylphthalate (DnBP). The results show a significant difference for all metabolites between the two periods, with the exception of MEP in women. The comparison of the two sets of results shows a decrease in urinary metabolites excretion from 2011 to 2016, statistically significant for the three phthalates included in Annex XIV of REACH. DEP, not currently included in the list for authorization, maintains a constant presence in the daily life of the population, particularly for women.

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.

Neonatal intensive care unit phthalate exposure and preterm infant neurobehavioral performance

Every year in the United States, more than 300,000 infants are admitted to neonatal intensive care units (NICU) where they are exposed to a chemical-intensive hospital environment during a developmentally vulnerable period. The neurodevelopmental impact of environmental exposure to phthalates during the NICU stay is unknown. As phthalate exposure during the third trimester developmental window has been implicated in neurobehavioral deficits in term-born children that are strikingly similar to a phenotype of neurobehavioral morbidity common among children born premature, the role of early-life phthalate exposure on the neurodevelopmental trajectory of premature infants may be clinically important. In this study, premature newborns with birth weight <1500g were recruited to participate in a prospective environmental health cohort study, NICU-HEALTH (Hospital Exposures and Long-Term Health), part of the DINE (Developmental Impact of NICU Exposures) cohort of the ECHO (Environmental influences on Child Health Outcomes) program. Seventy-six percent of eligible infants enrolled in the study. Sixty-four of 81 infants survived and are included in this analysis. 164 urine specimens were analyzed for phthalate metabolites using high-performance liquid chromatography/tandem mass spectrometry. The NICU Network Neurobehavioral Scale (NNNS) was performed prior to NICU discharge. Linear and weighted quantile sum regression quantified associations between phthalate biomarkers and NNNS performance, and between phthalate biomarkers and intensity of medical intervention. The sum of di(2-ethylhexyl) phthalate metabolites (∑DEHP) was associated with improved performance on the Attention and Regulation scales. Specific mixtures of phthalate biomarkers were also associated with improved NNNS performance. More intense medical intervention was associated with higher ∑DEHP exposure. NICU-based exposure to phthalates mixtures was associated with improved attention and social response. This suggests that the impact of phthalate exposure on neurodevelopment may follow a non-linear trajectory, perhaps accelerating the development of certain neural networks. The long-term neurodevelopmental impact of NICU-based phthalate exposure needs to be evaluated.

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.