Bisphenol A concentrations in maternal breast milk and infant urine

Effects of prenatal bisphenol A exposure on the hepatic transcriptome and proteome in rat offspring

Developmental exposure to bisphenol A (BPA) is associated with liver dysfunction and diseases in adulthood. The aims of this study were to assess the effects of prenatal BPA exposure on the hepatic transcriptome and proteome in female and male offspring and to understand adverse outcome pathways (AOPs) to observed phenotypic effects. Pregnant Wistar rats were exposed to 50 or 5000 μg BPA/kg bw/day, or 17β-estradiol (E2, 50 μg/kg bw/day) from embryonic day 3 to 18. The liver transcriptome and proteome profiles were analyzed in the newborn (postnatal day 1; PND1) and weaning (PND21) rat offspring. Based on the differentially expressed genes/proteins derived from transcriptome and proteome profiles, we performed pathway, transcription factor, and disease enrichment analyses. A principal component analysis of transcriptome data demonstrated that prenatal BPA exposure caused masculinization of the hepatic transcriptome in females. Both of transcriptomic and proteomic data showed that prenatal BPA exposure led to the disruption of cell cycle, lipid homeostasis, and hormone balance in offspring. Most of the effects at the transcript level were extended from newborn to weaning in males, but were moderated until weaning in females. The alterations at the transcript and protein levels were accordant with the observation of increases in body weight and anogenital distance and changes in hepatosomatic index in the offspring. Collectively, we constructed AOPs with evidence of sex- and age-specific actions of prenatal BPA exposure in the offspring.

Exposure to phenols during pregnancy and the first year of life in a new type of couple-child cohort relying on repeated urine biospecimens

BACKGROUND

Parabens, bisphenol A and triclosan have been forbidden or restricted in specific types of consumer goods in Europe and France. Limited biomonitoring data are available in France since the implementation of these regulations, and exposure data on infants is scarce worldwide. Understanding the predictors of phenol urinary concentrations will help identify potential targets for prevention.

AIM

We described levels, variability and predictors of exposure to 12 phenols in pregnant women and infants recruited between 2014 and 2017 in a French couple-child cohort.

METHODS

Among 479 pregnant women and 150 of their infants, we studied phenol urinary concentrations in within-subject, within-period pools of repeated urine samples collected during the second and third trimesters of pregnancy (up to 42 samples per woman), at 2 months and 12 months (up to 14 samples per infant). Time trends and associations with demographic, protocol, occupational and behavioral factors were studied using interval censored models to accommodate for undetected and unquantified urine concentrations.

RESULTS

Detection rates were above 90% for bisphenol A, ethylparaben, methylparaben, benzophenone-3 and triclosan and below 5% for bisphenol AF, B, F and triclocarban. Median levels of bisphenol A, bisphenol S, methylparaben, ethylparaben and propylparaben at 12 months were similar or higher than during pregnancy. For pregnant women all phenols but benzophenone-3 and bisphenol S showed a linear decrease between 2014 and 2017 (p-values < 0.02). Women with the shortest education (primary and secondary school) had higher urinary concentrations of triclosan (β = 0.58 (95% confidence interval (CI), -0.04; 1.20)), ethyl (β = 0.43 (95%CI, 0.03; 0.84)) and propyl paraben (β = 1.39 (95%CI, 0.55; 2.24)) than those with the longest education. Cashiers had higher conccentrations of bisphenol S (β = 0.99 (95%CI, -0.11; 2.09)) but not of bisphenol A (β = -0.04 (95%CI, -0.26; 0.19)) than unemployed women.

CONCLUSIONS

Despite recent regulations, bisphenol A, triclosan and paraben detection rates were high in women and young infants. High bisphenol and paraben median levels at 12 months require further investigation as early infancy is a sensitive period for exposure to environmental contaminants.

Plastics derived endocrine-disrupting compounds and their effects on early development

Despite the fact that the estrogenic effects of bisphenols were first described 80 years ago, recent data about its potential negative impact on birth outcome parameters raises a strong rationale to investigate further. The adverse health effects of plastics recommend to measure the impacts of endocrine-disrupting compounds (EDCs) such as bisphenols (BPA, BPS, BPF), bis(2-ethylhexyl) phthalate, and dibutyl phthalate (DBP) in human health. Exposure to these compounds in utero may program the diseases of the testis, prostate, kidney and abnormalities in the immune system, and cause tumors, uterine hemorrhage during pregnancy and polycystic ovary. These compounds also control the processes of epigenetic transgenerational inheritance of adult-onset diseases by modulating DNA methylation and epimutations in reproductive cells. The early developmental stage is the most susceptible window for developmental and genomic programming. The critical stages of the events for a normal human birth lie between the many transitions occurring between spermatogenesis, egg fertilization and the fully formed fetus. As the cells begin to grow and differentiate, there are critical balances of hormones, and protein synthesis. Data are emerging on how these plastic-derived compounds affect embryogenesis, placentation and feto-placental development since pregnant women and unborn fetuses are often exposed to these factors during preconception and throughout gestation. Impaired early development that ultimately influences fetal outcomes is at the center of many developmental disorders and contributes an independent risk factor for adult chronic diseases. This review will summarize the current status on the impact of exposure to plastic derived EDCs on the growth, gene expression, epigenetic and angiogenic activities of the early fetal development process and their possible effects on birth outcomes.

Associations of lifestyle factors with phthalate metabolites, bisphenol A, parabens, and triclosan concentrations in breast milk of Korean mothers

The toxicity of endocrine disruptors depends on the synergistic interactions of biological, environmental, and behavioral factors. The specific effects of diet, consumer product use, and behaviors, however, are debated in the literature, particularly with regard to endocrine disruptors found in breast milk. This study aimed to measure the levels of phthalate metabolites, bisphenol A, parabens, and triclosan in breast milk and to investigate their associations with various lifestyle factors. The breast milk samples as well as surveys were collected from 221 first-time mothers throughout South Korea and each sample was analyzed for the presence of 15 endocrine disruptors. Phthalate metabolites were detected in 5.4-83.3% of the samples, with median concentrations of 0.08-1.72 μg/L, while bisphenol A, parabens, and triclosan were detected in 25.8-88.2% of the samples, with median concentrations of 0.12-1.47 μg/L. High levels of endocrine disruptors were associated with frequent consumption of fish and cup noodles; the use of plastic and disposable food containers; the use of air fresheners, lotions and make-up; the purchase of new furniture; and socioeconomic status. We also observed the potential role of moderate walking activity on the reduction of these chemicals in breast milk. Our data provide evidence of the potential effects of diet, consumer products, and behavior on the presence of phthalate metabolites, bisphenol A, parabens, and triclosan in breast milk. Future studies should include community or regional impact on a mothers' exposure to endocrine disruptors, to assess the joint contribution of both individual and neighborhood factors.

Effect of Exposure of Plastic Infant Feeding Bottle Leached Water on Biochemical, Morphological and Oxidative Stress Parameters in Rats

Bisphenol A (BPA) is leached out from plastic infant feeding bottles that are filled with warm milk/water due to high temperatures, exposing the infants to BPA. The present study aims to understand the effects of ingestion of BPA leached from plastic infant feeding bottle and delineate the underlying mechanisms in rats. In this study, adult rats of Wistar strain were divided into 3 groups. In the first group, the rats consumed normal food and tap water ad libitum. In the second group, the rats ingested BPA (20 µg/kg bodyweight/day, orally). In the third group, the rats drank water leached from plastic infant feeding bottles. After 30days, tests involving biochemical parameters, histopathological examination, and oxidative stress enzyme markers were performed, and the levels of BPA in plastic-leached water were estimated by HPLC analysis. There were significant biochemical changes in the form of increased alkaline phosphatase (ALP), creatine kinase-muscle/brain (CK-MB), and lactate dehydrogenase (LDH) levels in both treated groups as compared to control group, accompanied by structural damage to the vital organs, and lipid peroxidation, glutathione reductase, and catalase activity were also high in the treated groups. Further, the BPA concentration in plastic leached water was estimated to be 0.1 ± 0.02 µg/mL.

Bisphenol analogue concentrations in human breast milk and their associations with postnatal infant growth

Many studies show that bisphenol A (BPA) is widespread in human breast milk. However, the occurrence of other bisphenol analogues (BPs), including bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF), in breast milk is still not well known. In this study, breast milk samples were collected from 190 women in Hangzhou, China, with the aims to characterize the occurrence of BPA, BPS, BPF, and BPAF in these samples and to investigate their effects on postnatal growth of infants through breast milk consumption. BPA (mean 2.5 ng/mL, range < LOD-15 ng/mL) was the most abundant BP in breast milk, followed by BPS (0.19 ng/mL, <LOD-1.3 ng/mL) and BPAF (0.092 ng/mL, <LOD-0.58 ng/mL). BPF was not detected in all breast milk samples. We firstly found that breast milk concentrations of BPA were negatively correlated with infant's weight or length gain rate. Daily intakes (DIs) of BPs via the consumption of breast milk were calculated for infants, and the mean DI values were 531 ng/kg/day, 53 ng/kg/day, and 24 ng/kg/day for BPA, BPS, and BPAF, respectively. Overall, this study firstly demonstrats that the lactation exposure to BPA through breast milk consumption may affect the postnatal growth of infants.

Neuro-toxic and Reproductive Effects of BPA

Background:

Bisphenol A (BPA) is one of the highest volume chemicals produced worldwide. It has recognized activity as an endocrine-disrupting chemical and has suspected roles as a neurological and reproductive toxicant. It interferes in steroid signaling, induces oxidative stress, and affects gene expression epigenetically. Gestational, perinatal and neonatal exposures to BPA affect developmental processes, including brain development and gametogenesis, with consequences on brain functions, behavior, and fertility.

Methods:

This review critically analyzes recent findings on the neuro-toxic and reproductive effects of BPA (and its ana-logues), with focus on neuronal differentiation, synaptic plasticity, glia and microglia activity, cognitive functions, and the central and local control of reproduction.

Results:

BPA has potential human health hazard associated with gestational, peri- and neonatal exposure. Beginning with BPA’s disposition, this review summarizes recent findings on the neurotoxicity of BPA and its analogues, on neuronal dif-ferentiation, synaptic plasticity, neuro-inflammation, neuro-degeneration, and impairment of cognitive abilities. Furthermore, it reports the recent findings on the activity of BPA along the HPG axis, effects on the hypothalamic Gonadotropin Releas-ing Hormone (GnRH), and the associated effects on reproduction in both sexes and successful pregnancy.

Conclusion:

BPA and its analogues impair neuronal activity, HPG axis function, reproduction, and fertility. Contrasting re-sults have emerged in animal models and human. Thus, further studies are needed to better define their safety levels. This re-view offers new insights on these issues with the aim to find the “fil rouge”, if any, that characterize BPA’s mechanism of action with outcomes on neuronal function and reproduction.

Bisphenol A in infant urine and baby-food samples among 9- to 15-month-olds

Diet is the predominant source of bisphenol A (BPA) intake, but limited data are available on BPA levels in the diet of younger infants. This study investigated BPA levels in baby-food and urine samples collected from young infants (under 2 years old). Samples of homemade baby food (n = 210) and urine (n = 187) were collected at 9, 12, and 15 months after birth from a panel of Korean infants (n = 173). BPA levels in urine and food were measured using HPLC-MS/MS and GC-MS, respectively. BPA was above the limit of detection (LOD) in 85.5-85.7% of the urine samples and 32.5-76.3% of the baby-food samples. The median levels of BPA were 0.45 ng/g wet weight (IQR: not detectable to 5.16 ng/g wet weight) in homemade baby food, 0.93 μg/L (IQR: <LOD to 2.66 μg/L) in unadjusted urine samples, and 0.94 μg/L (IQR: <LOD to 2.80 μg/L) in urine samples adjusted for specific gravity. The BPA levels detected in this study were comparable or lower compared to previously reported levels of BPA in baby-food and infant urine samples. The BPA concentrations in the baby food of 15-month-old children (median: 5.09 ng/g) were significantly greater than those detected at 9 or 12 months of age (median: <LOD and 0.47 ng/g, respectively). Considering that the dietary changes from solid food with high water content to solid food as infants grew were accompanied by greater exposure to BPA, it is noteworthy that urinary BPA levels did not significantly differ according to infants' age. These results suggest that solid food with high water content did not drive the internal dose in younger infants, implying that there may have been other sources of exposure in their baby-food (other than weaning-food) and the environment, although further study would be needed to confirm this possibility.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Phthalate and BPA Exposure in Women and Newborns through Personal Care Product Use and Food Packaging

Phthalates and bisphenol A (BPA) are used in some personal care products (PCPs) and containers for food processing and packaging. The Plastics and Personal-Care Product use in Pregnancy (P4) Study (2009-10) explored the association between PCP use during pregnancy and the postpartum period among 80 pregnant women and 55 infants and BPA and phthalate concentrations in multiple maternal and infant urine specimens collected throughout the study (n = 1260 samples). The type, frequency, and timing of PCP and food packaging use 24 h before and during the urine collection period was collected at 5 time points for the mother using prospective diaries. Infant urine was collected up to 2 times before 3 months of age, and mothers answered questions about infant feeding and PCP use on their baby. In mothers, monoethyl phthalate (MEP) metabolite concentrations were significantly higher when women reported using makeup or body lotion in the last 24 h. MEP concentrations were consistently higher when the usage occurred within 0-6 h before the urine sample collection for almost all of the PCP categories. Infant lotion or baby powder application in the previous 24 h was associated with higher phthalate metabolite concentrations in infants. Total BPA metabolite concentrations were lower in exclusively breastfed infants compared to those who were exclusively formula fed or breastfed with supplementation. Given that PCPs tend to undergo frequent formulation changes, which could impact the relative importance of a certain product type as a source of exposure, continued research of this type is warranted.

Organophosphorus Flame Retardants and Plasticizers in Breast Milk from the United States

Organophosphate esters (OPEs) are used in consumer products as flame retardants and plasticizers. Little is known, however, about the occurrence and profiles of OPEs in human milk. In this study, 14 OPEs were measured in 100 breast milk samples collected from the United States during the period of 2009-2012, using high-performance liquid chromatography and tandem mass spectrometry. The sum concentrations of 14 OPEs in human milk ranged from 0.670 to 7.83 ng/mL, with a mean value of 3.61 ng/mL. The highest mean concentration was found for tris-2-butoxyethyl phosphate (TBOEP, 1.44 ± 0.789 ng/mL), followed by tri-iso-butyl phosphate (TIBP, 0.569 ± 0.272 ng/mL) and tri-n-butyl phosphate (TNBP, 0.539 ± 0.265 ng/mL), which were the dominant OPEs found in breast milk at detection frequencies of >80%. No significant differences were observed between various maternal/infant characteristics and OPE concentrations (p > 0.05), except for TBOEP, for which the median concentrations in Hispanic mothers (0.765 ng/mL) were 2 times lower than those in non-Hispanic mothers (1.48 ng/mL) (p < 0.05). On the basis of the recommended daily milk ingestion rate, the average and the highest daily intakes of total OPEs were calculated to be in the range of 300-542 and 504-911 ng (kg of body weight)^-1 day^-1, respectively. The estimated daily intakes of OPEs did not exceed the current reference doses. Our study establishes baseline data for OPE exposure in breast-fed American children.

Urinary concentrations of environmental phenols and their associations with breast cancer incidence and mortality following breast cancer

BACKGROUND

Environmental phenols, compounds used widely in personal care and consumer products, are known endocrine disruptors. Few epidemiologic studies have examined the association of phenol biomarkers with breast cancer incidence and, to our knowledge, none have considered associations with mortality following breast cancer. We examined seven urinary phenol biomarkers in association with breast cancer incidence and subsequent mortality, and examined effect measure modification by body mass index (BMI).

METHODS

Participants included 711 women with breast cancer and 598 women without breast cancer who were interviewed for the population-based Long Island Breast Cancer Study Project. Among women with breast cancer, phenol biomarkers were quantified in spot urine samples collected on average within three months of a first diagnosis of primary in situ or invasive breast cancer in 1996-1997. Women with breast cancer were monitored for vital status using the National Death Index. After a median follow-up of 17.6 years, we identified 271 deaths, including 98 deaths from breast cancer. We examined creatinine-corrected phenol concentrations and the sum of parabens (Σparabens) in association with breast cancer incidence using logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs), and with mortality using Cox regression to estimate hazard ratios (HRs) and 95% CIs. We evaluated multiplicative effect measure modification using cross-product terms in nested models.

RESULTS

The highest (vs lowest) quintiles of urinary methylparaben, propylparaben, and Σparabens were associated with risk of breast cancer with ORs ranging from 1.31 to 1.50. Methylparaben, propylparaben, and Σparabens were also associated with all-cause mortality HRs ranging from 0.68 to 0.77. Associations for breast cancer incidence were more pronounced among women with BMI < 25.0 kg/m2 than among women with BMI ≥ 25.0 kg/m2; however, associations for mortality were more pronounced among women with BMI ≥ 25 kg/m2 than among women with BMI < 25 kg/m2.

CONCLUSIONS

Select parabens may have differential associations with risk of developing breast cancer and mortality following breast cancer.

The adverse health effects of bisphenol A and related toxicity mechanisms

Bisphenol A (BPA) is an industrial component commonly used in synthesis of polycarbonate plastics, epoxy resin and other polymer materials. Due to its mass productions and widespread applications, the presence of BPA is ubiquitous in the environment. BPA can enter the body via different ways such as digestive tract, respiratory tract and dermal tract. As an endocrine disruptor, BPA has estrogen-like and anti-androgen effects causing damages to different tissues and organs, including reproductive system, immune system and neuroendocrine system, etc. Recently, it has been shown that BPA could induce carcinogenesis and mutagenesis in animal models. Here, the underlying mechanisms of BPA-induced multi-organ toxicity were well summarized, involving the receptor pathways, disruption of neuroendocrine system, inhibition of enzymes, modulation of immune and inflammatory responses, as well as genotoxic and epigenetic mechanisms. The aim of this review is to compile the available current research data regarding BPA and provide an overview of the current status of BPA exposure and relevant health effects covering reproductive, developmental, metabolic, immuno, respiratory, hepatic and renal toxicity and carcinogenesis of BPA. This review provides comprehensive data of BPA toxicity on human health and related mechanisms. We also identify any missing data which should be addressed by further studies.

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

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

Review: Maternal programming of development in the pig and the lactocrine hypothesis

Maternal effects on development are profound. Together, genetic and epigenetic maternal effects define the developmental trajectory of progeny and, ultimately, offspring phenotype. Maternally provisioned environmental conditions and signals affect conceptus, fetoplacental and postnatal development from the time of conception until weaning. In the pig, reproductive tract development is completed postnatally. Porcine uterine growth and uterine endometrial development occur in an ovary-independent manner between birth (postnatal day = PND 0) and PND 60. Milk-borne bioactive factors (MbFs), exemplified by relaxin, communicated from lactating dam to nursing offspring via a lactocrine mechanism, represent an important source of extraovarian uterotrophic support in the neonatal pig. Lactocrine deficiency from birth affects both the neonatal porcine uterine developmental program and trajectory of uterine development, with lasting consequences for endometrial function and uterine capacity in adult female pigs. The potential lactocrine signaling window extends from birth until the time of weaning. However, it is likely that the maternal lactocrine programming window - that period when MbFs communicated to nursing offspring have the greatest potential to affect critical organizational events in the neonate - encompasses a comparatively short period of time within 48 h of birth. Lactocrine deficiency from birth was associated with altered patterns of endometrial gene expression in neonatally lactocrine-deficient adult gilts during a critical period for conceptus-endometrial interaction on pregnancy day 13, and with reduced litter size, estimated at 1.4 pigs per litter, with no effect of parity. Data were interpreted to indicate that reproductive performance of female pigs that do not receive sufficient colostrum from birth is permanently impaired. Observations to date suggest that lactocrine-dependent maternal effects program postnatal development of the porcine uterus, endometrial functionality and uterine capacity. In this context, reproductive management strategies and husbandry guidelines should be refined to ensure that such practices promote environmental conditions that will optimize uterine capacity and fecundity. This will entail careful consideration of factors affecting lactation, the quality and abundance of colostrum/milk, and practices that will afford neonatal pigs with the opportunity to nurse and consume adequate amounts of colostrum.

The dark side of the breastfeeding: In the light of endocrine disruptors

Breastfeeding plays an essential role in the healthy development of a newborn, but human milk is obviously compromised by pollutants from our environment. The main contaminants of human milk with endocrine-disrupting compound (EDCs) have raised concern for public and environmental health. Bisphenol A (BPA), which can leach from plastics, are among the most well-studied. Since EDs are known to cross the mammary gland barrier and BPA may accumulate in the neonate, “BPA-free” products have been introduced to the market. However, recent studies have shown that alternative bisphenols (e.g. BPS, BPF) can be detected in breast milk, have ED activities and may have developmental effects similar to BPA.

Biomonitoring of bisphenols A, F, S in human milk and probabilistic risk assessment for breastfed infants

The present study addresses the presence of bisphenols A (BPA) and its analogs bisphenol F (BPF) and S (BPS) in milk of 120 mothers living in Valencia (Spain) and participating in the BETTERMILK project (year 2015). We also studied the factors that could influence the BPA levels and estimated the exposure and the risk for breast fed infants. The frequency of detection of total (conjugated + unconjugated) and unconjugated-BPA were 83% and 77%, with a geometric mean of 0.29 ng/mL and 0.15 ng/mL, respectively. The frequency of detection was much lower for total-BPF (22%) and total-BPS (1.1%). The place of residence of the mother and the use of personal care products showed significant association with BPA concentrations. The estimated daily intake of total-BPA for breastfed infants amounted to a geometric mean of 0.04 μg/kg bw and a 95th percentile of 1.0 μg/kg bw, below the tolerable daily intake of 4 μg/kg bw-day established by EFSA. To our knowledge, this is the largest biomonitoring study of bisphenols in human milk in Europe.

Transgenerational Effects of Endocrine-Disrupting Chemicals on Male and Female Reproduction

Endocrine-disrupting chemicals are known to interfere with normal reproductive function and hormone signaling. Phthalates, bisphenol A, pesticides, and environmental contaminants such as polychlorinated biphenyls and dioxins are known endocrine-disrupting chemicals that have been shown to negatively affect both male and female reproduction. Exposure to these chemicals occurs on a daily basis owing to these compounds being found in plastics, personal care products, and pesticides. Recently, studies have shown that these chemicals may cause transgenerational effects on reproduction in both males and females. This is of concern because exposure to these chemicals prenatally or during adult life can negatively impact the reproductive health of future generations. This mini-review summarizes the endocrine-disrupting chemicals that humans are exposed to on a daily basis and what is known about the transgenerational effects that these chemicals may have on male and female reproduction.

Developmental exposure to a very low dose of bisphenol A induces persistent islet insulin hypersecretion in Fischer 344 rat offspring

BACKGROUND

In children with obesity, accentuated insulin secretion has been coupled with development of type 2 diabetes mellitus (T2DM). Bisphenol A (BPA) is a chemical with endocrine- and metabolism-disrupting properties which can be measured in a majority of the population. Exposure to BPA has been associated with the development of metabolic diseases including T2DM.

OBJECTIVE

The aim of this study was to investigate if exposure early in life to an environmentally relevant low dose of BPA causes insulin hypersecretion in rat offspring.

METHODS

Pregnant Fischer 344 rats were exposed to 0.5 (BPA0.5) or 50 (BPA50) µg BPA/kg BW/day via drinking water from gestational day 3.5 until postnatal day 22. Pancreata from dams and 5- and 52-week-old offspring were procured and islets were isolated by collagenase digestion. Glucose-stimulated insulin secretion and insulin content in the islets were determined by ELISA.

RESULTS

Basal (5.5 mM glucose) islet insulin secretion was not affected by BPA exposure. However, stimulated (11 mM glucose) insulin secretion was enhanced by about 50% in islets isolated from BPA0.5-exposed 5- and 52-week-old female and male offspring and by 80% in islets from dams, compared with control. In contrast, the higher dose, BPA50, reduced stimulated insulin secretion by 40% in both 5- and 52-week-old female and male offspring and dams, compared with control.

CONCLUSION

A BPA intake 8 times lower than the European Food Safety Authority's (EFSA's) current tolerable daily intake (TDI) of 4 µg/kg BW/day of BPA delivered via drinking water during gestation and early development causes islet insulin hypersecretion in rat offspring up to one year after exposure. The effects of BPA exposure on the endocrine pancreas may promote the development of metabolic disease including T2DM.

Preliminary study on bisphenol A levels and possible exposure history of mother and exclusively breastfed infant pairs

The aims of this study were to determine bisphenol A (BPA) levels in breast milk and urine specimens of healthy mother and exclusively breastfed infant pairs having no known BPA exposure, and also to examine the relationship between BPA levels and possible BPA exposure history. Forty mothers and their 1-2-month-old exclusively breastfeed infant were included in the study. The questionnaires about sociodemographic characteristics and possible BPA exposure history were filled out. Breast milk and urine samples were taken. BPA analyses of these samples were conducted using high-performance liquid chromatography coupled with mass spectrometry. All mother-infant pairs showed detectable BPA concentrations. The geometric means of BPA levels in breast milk, maternal urine, and infant urine were determined as 0.12 μg/L (0.03-0.59), 0.12 μg/L (0.03-0.73), and 0.13 μg/L (0.02-0.44), respectively. Infants whose mothers were consuming yoghurt in plastic containers had relatively higher urinary BPA levels (p = 0.00). Mothers consuming hot beverages in plastic glass showed higher breast milk BPA levels (p = 0.033). There were no statistical associations between BPA levels and the use of plastic materials and tools (p > 0.05).Conclusion: The measurable BPA concentrations in all breast milk specimens of healthy mothers may reflect possible exposure from dietary or non-dietary sources. Exclusively, breastfed healthy infants without any known BPA exposure may be exposed to BPA from their mothers through breastfeeding. What is Known: • Fetuses, neonates and infants are exposed to BPA from their mothers through placental transfer and breastfeeding. • Breast milk is considered a continuous low-level exposure to BPA. What is New: • BPA was detected in 100% of maternal urine, infant urine, and breast milk in healthy mother-infant pairs having no known BPA exposure. • The measurable amount of BPA in breast milk and infant urine may reflect possible BPA exposure of mother-infant pairs.

Maternal bisphenol A exposure disrupts spermatogenesis in adult rat offspring

Bisphenol A (BPA) is an endocrine-disrupting chemical (EDC) that is widely used in the manufacturing of plastics and inner linings of food cans. Previously, it was reported that BPA disturbed the sexual dimorphic nucleus of the hypothalamus and delaying the onset of puberty attributed to an estrogenic action. In addition, BPA during the perinatal period increased LH serum concentrations in male offspring of dams at doses below the reproductive NOAEL (No Observable Adverse Effect Level) based upon World Health Organization guidelines. Based upon these findings, the objective of this study was to (1) determine the effects of perinatal treatment with low doses of BPA on regulation of spermatogenesis in adult offspring and (2) elucidate molecular mechanisms involved in the pathogenesis of gonadal dysfunction. The expression of genes related to spermatogenesis was disrupted with adverse consequences on sperm production, reserves, and function. Both BPA treated groups exhibited reduction in sperm production and epithelial height of seminiferous tubules, accompanied by diminished integrity of the acrosome and plasma membrane, decreased mitochondrial activity and increased incidence of morphological abnormalities. The sperm transit time was also slower. However, only in the group receiving the higher BPA dose was transcript expression of genes affected (reduced Ar and increased Esr1). It is of interest that serum testosterone levels were elevated in the same group where Ar was decreased. Data suggest that exposure to low BPA doses during hypothalamic sexual differentiation period produces permanent deleterious effects on spermatogenesis in adulthood.

Early-life intake of major trace elements, bisphenol A, tetrabromobisphenol A and fatty acids: Comparing human milk and commercial infant formulas

In the present study, the presence of a wide spectrum of major and trace elements (As, Ag, Al, Ba, Cd, Co, Cr, Cu, Hg, Mn, Ni, Sr, Sb, Se, Sn, Pb, V, and Zn), fatty acids, as well as some pollutants like free and total BPA and tetrabromobisphenol A (TBBPA), was analysed in human milk (n = 53) and infant formula (n = 50) samples. In addition, the infant exposure to these chemicals was assessed. The content of free BPA and several elements (Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Sn, Sr, and Zn) was higher (p < 0.01) in infant formula samples. Furthermore, human milk contained levels of BPA and elements that, in almost all cases, were well below their respective EFSA and/or WHO thresholds, being also independent of the maternal characteristics (e.g., age, BMI or breastfeeding period). The fatty acid profiling also revealed major differences between human milk and infant formulas, which should be taken in account in the development of new formulas as well as in specific recommendations for the diet of breastfeeding mothers. Anyway, the results of this study reinforce that breastfeeding should be always the first feeding option in early life.

Mutual promotion of apoptosis and autophagy in prepubertal rat testes induced by joint exposure of bisphenol A and nonylphenol

BPA and NP are both typical endocrine disruptors, the exposed populations are widespread, and the health risks mustn't be ignored. However, the interactions between them on spermatogenesis are rarely mentioned. And the underlying mechanism is unclear yet. In the present study, prepubertal SD rats were exposed to different low doses of BPA and NP separately or jointly for 4 weeks. The results indicate that the joint exposure induced excessive apoptosis and autophagy in the testes, as proved by a series of characteristics such as chromatin condensation and autophagosomes formation. Besides, endocrine disorders and oxidative stress were also caused by the exposure. Apoptosis was mediated by the mitochondrial apoptosis pathway, since the Bax and Caspase-3 gene expressions significantly increased with a prominent decrease of Bcl-2. While autophagy was caused by the inhibition of the Akt/mTOR pathway, as the expressions of the downstream genes Beclin-1, Atg5, Atg12 and the split of LC3 protein increased altogether. Worse yet, autophagy and apoptosis might reinforce each other and make the situation more severe in the joint group. What's more, remarkable histopathological changes such as spermatogenic epithelium atrophy, germ cell loss, and various ultrastructural modifications were strongly related to the apoptosis and autophagy. In aggregate, this study shows the enormous risk on male reproductive system brought by the interactions between BPA and NP. The findings provide a broader vision to understand the roles of apoptosis and autophagy induced by the joint exposure in the aggravation of spermatogenesis impairment, which could be a reference for the situation of complex EDCs exposure-induced male reproductive toxicity, and possibly inspire us to find new ideas for preventive and therapeutic treatments.

Obesogenic Endocrine Disrupting Chemicals: Identifying Knowledge Gaps

Endocrine disrupting chemicals (EDCs) are compounds that are part of everyday consumer products and industrial manufacturing processes. EDCs can interfere with the endocrine system, including the adipose tissue. Accumulating evidence from epidemiological, animal, and in vitro studies demonstrates that EDCs can alter body weight, adipose tissue expansion, circulating lipid profile, and adipogenesis, with some resulting in transgenerational effects. These outcomes appear to be mediated through multiple mechanisms, from nuclear receptor binding to epigenetic modifications. A better understanding of the signaling pathways via which these EDCs contribute to an obesogenic phenotype, the interaction amongst complex mixtures of obesogenic EDCs, and the risks they pose relative to the obesity epidemic are still needed for risk assessment and development of prevention strategies.

Environmental Chemicals in Breast Milk and Formula: Exposure and Risk Assessment Implications

BACKGROUND

Human health risk assessment methods have advanced in recent years to more accurately estimate risks associated with exposure during childhood. However, predicting risks related to infant exposures to environmental chemicals in breast milk and formula remains challenging.

OBJECTIVES

Our goal was to compile available information on infant exposures to environmental chemicals in breast milk and formula, describe methods to characterize infant exposure and potential for health risk in the context of a risk assessment, and identify research needed to improve risk analyses based on this type of exposure and health risk information.

METHODS

We reviewed recent literature on levels of environmental chemicals in breast milk and formula, with a focus on data from the United States. We then selected three example publications that quantified infant exposure using breast milk or formula chemical concentrations and estimated breast milk or formula intake. The potential for health risk from these dietary exposures was then characterized by comparison with available health risk benchmarks. We identified areas of this approach in need of improvement to better characterize the potential for infant health risk from this critical exposure pathway.

DISCUSSION

Measurements of chemicals in breast milk and formula are integral to the evaluation of risk from early life dietary exposures to environmental chemicals. Risk assessments may also be informed by research investigating the impact of chemical exposure on developmental processes known to be active, and subject to disruption, during infancy, and by analysis of exposure-response data specific to the infant life stage. Critical data gaps exist in all of these areas.

CONCLUSIONS

Better-designed studies are needed to characterize infant exposures to environmental chemicals in breast milk and infant formula as well as to improve risk assessments of chemicals found in both foods. https://doi.org/10.1289/EHP1953.

Evaluation of Prenatal Exposure to Bisphenol Analogues on Development and Long-Term Health of the Mammary Gland in Female Mice

BACKGROUND

Continued efforts to phase out bisphenol A (BPA) from consumer products have been met with the challenges of finding safer alternatives.

OBJECTIVES

This study aimed to determine whether early-life exposure to BPA and its related analogues, bisphenol AF (BPAF) and bisphenol S (BPS), could affect female pubertal mammary gland development and long-term mammary health in mice.

METHODS

Timed pregnant CD-1 mice were exposed to vehicle, BPA (0.5, 5, 50 mg/kg), BPAF (0.05, 0.5, 5 mg/kg), or BPS (0.05, 0.5, 5 mg/kg) via oral gavage between gestation days 10–17. Mammary glands were collected from resulting female offspring at postnatal day (PND) 20, 28, 35, and 56, and at 3, 8, and 14 months for whole mount, histopathological evaluation, and quantitative real-time polymerase chain reaction (qPCR); serum steroid concentrations were also measured at these time points.

RESULTS

In the bisphenol-exposed mice, accelerated mammary gland development was evident during early puberty and persisted into adulthood. By late adulthood, mammary glands from bisphenol-exposed female offspring exhibited adverse morphology in comparison with controls; most prominent were undifferentiated duct ends, significantly more lobuloalveolar hyperplasia and perivascular inflammation, and various tumors, including adenocarcinomas. Effects were especially prominent in the BPAF 5 mg/kg and BPS 0.5 mg/kg groups. Serum steroid concentrations and mammary mRNA levels of Esr1, Pgr, Ar, and Gper1 were similar to controls.

CONCLUSIONS

These data demonstrate that prenatal exposure of mice to BPAF or BPS induced precocious development of the mammary gland, and that siblings were significantly more susceptible to spontaneous preneoplastic epithelial lesions and inflammation, with an incidence greater than that observed in vehicle- and BPA-exposed animals. https://doi.org/10.1289/EHP3189.

Bisphenol A distribution in serum, urine, placenta, breast milk, and umbilical cord serum in a birth panel of mother-neonate pairs

Bisphenol A (BPA) exposure during the perinatal and postnatal periods increases the susceptibility to disease over the life cycle. However, information on the BPA delivered to fetuses or infants via the placenta and breastfeeding is limited. We determined the BPA exposure levels in various bodily fluids and tissues of pregnant women and described fetus and infant exposures to BPA based on associations and BPA ratios in mother-neonate paired samples. Maternal serum, urine, placenta, breast milk, cord serum, and neonatal urine samples were collected from 318 mother-neonate pairs at six university hospitals in Korea. BPA levels were detected using liquid chromatography tandem mass spectrometry. The ratios of the BPA levels in the other sample types to the levels in maternal serum were calculated. BPA was detected in 79.5-100% of the maternal and fetal samples. The median BPA concentration in the samples decreased in the order of neonatal urine (4.75ng/mL), maternal urine (2.86ng/mL), cord serum (1.71ng/mL), maternal serum (1.56ng/mL), breast milk (0.74ng/mL), and the placenta (0.53ng/g). We estimated the ratios of BPA levels in the other sample types to those in maternal serum. The median (95th percentile) cord serum-to-maternal serum ratio was 1.12 (15.2) for 160 mother-fetal pairs, in which BPA was detected in both samples. The placenta-, maternal urine-, neonatal urine-, and breast milk-to-maternal serum ratios were 0.28 (5.31), 1.79 (29.9), 1.98 (28.2), and 0.51 (10.5), respectively. In addition, the median (95th percentile) cord serum-to-placenta ratio was 4.03 (45.8), and the neonatal urine-to-cord serum ratio was 1.95 (25.6). The 95th percentile values were 14-20-fold greater than the medians. Urine contained the highest BPA concentrations, followed by serum, breast milk, and the placenta. The variations of BPA ratio show individual differences in the amounts of BPA delivered from mother to fetus.

Chemical Contaminants in Raw and Pasteurized Human Milk

BACKGROUND

Environmental contaminants ranging from legacy chemicals like p,p'-dichlorodiphenyltrichloroethane (DDT) to emerging chemicals like phthalates are ubiquitous. Research aims/questions: This research aims to examine the presence and co-occurrence of contaminants in human milk and effects of pasteurization on human milk chemical contaminants.

METHODS

We analyzed human milk donated by 21 women to a milk bank for 23 chemicals, including the persistent organic pollutants (POPs) polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), dichlorodiphenyltrichloroethane (DDT), and dichlorodiphenyldichloroethylene (DDE) isomers that are known to sequester in adipose tissue, along with the current-use and nonpersistent pesticides chlorpyrifos and permethrin, phthalates, and bisphenol A (BPA). Human milk was analyzed raw and pasteurized for these chemicals using gas chromatography-tandem mass spectrometry for the POPs and high-performance liquid chromatography-tandem mass spectrometry for non-POPs.

RESULTS

Within the different chemical classes, PBDE47, PCB153, ppDDE, and MEHHP (phthalate metabolite) had the highest median concentrations and were observed in all samples. We also observed chlorpyrifos and BPA in all samples and permethrin in 90% of the samples tested. Only two chemicals, chlorpyrifos and permethrin, were susceptible to substantial degradation from pasteurization, a standard method for processing donated human milk.

CONCLUSION

We detected 19 of 23 chemicals in all of our prepasteurized milk and 18 of 23 chemicals in all of our pasteurized milk. Pasteurization did not affect the presence of most of the chemicals. Future research should continue to explore human milk for potential chemical contamination and as a means to surveil exposures among women and children.

Thyroid-disrupting chemicals and brain development: an update

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

Occurrence of bisphenol S in the environment and implications for human exposure: A short review

As a substitute of bisphenol A (BPA), bisphenol S (BPS) has been applied in consumer products present in our daily lives. With a similar chemical structure as BPA, BPS has also been demonstrated as an exogenous endocrine disrupting chemical. Compared with a large number of studies on BPA, investigation on BPS has remained limited. In this study, we reviewed the literature of BPS mainly published during 2010-2017, including its environmental distributions, toxicities, and human exposure. The data demonstrated that BPS is now ubiquitous in the environment and found worldwide, but generally with concentration levels lower than BPA in various environment media, including water, sediment, sludge, indoor dust and air, consumer products, and human urine. However, we found that the concentration levels of BPS in aquatic environments, especially water samples, were almost comparable or equal to that of BPA. Our summary also indicated that process speed of substituting BPA with BPS in consumer products in the U.S. was relatively faster than other countries. In addition, we summarized the toxicities of exposure to BPS both in vivo and in vitro experiments. The current data supports that exposure to BPS may have adverse effects on reproductive systems, endocrine systems, and nervous systems in animals and humans, and may trigger oxidative stress. The occurrence of BPS was frequently reported in human urine, but rarely in other human samples. The current research indicates that food is the dominant source for human exposure to BPS, and the contribution of personal care product usage is low. The occurrence of BPS and their metabolites in the human body and the guidelines for BPS exposure merit further investigation.

Plastic toys as a source of exposure to bisphenol-A and phthalates at childcare facilities

Infants and toddlers are constantly exposed to toys at childcare facilities. Toys are made of a variety of plastics that often use endocrine-disrupting chemicals such as bisphenol-A (BPA) and phthalates as their building blocks. The goal of this study was to assess the non-dietary exposure of infants and toddlers to BPA and phthalates via leaching. We have successfully developed wipe tests to evaluate the leachability of BPA and phthalates from toys used at several day care facilities in Philadelphia. Our studies have shown an average leaching of 13-280 ng/cm² of BPA and phthalates. An estimate of total exposure of infants to BPA and phthalates is reported. The leaching of the chemicals was observed to be dependent on the washing procedures and the location of the day care facilities. Using bleach/water mixture two or more times a week to clean the toys seems to reduce the leaching of chemicals from the toys. There is a huge data gap in the estimated intake amounts and reported urinary concentrations; this is the first study that provides valuable information to address these data gaps in the existing literature.

Recent advances on bisphenol-A and endocrine disruptor effects on human prostate cancer

Endocrine disrupting chemicals (EDCs) are man-made substances widespread in the environment that include, among many others, bisphenol A (BPA), organochlorinated pesticides and hormone derivatives detectable in meat from animals raised in concentrated animal feeding operations. Increasing evidence indicates that EDCs have a negative impact on human health as well as on male and female fertility. They may also be associated with some endocrine diseases and increased incidence of breast and prostate cancer. This review aims to summarize available data on the (potential) impact of some common EDCs, focusing particularly on BPA, prostate cancer and their mechanisms of action. These compounds interfere with normal hormone signal pathway transduction, resulting in prolonged exposure of receptors to stimuli or interference with cellular hormone signaling in target cells. Understanding the effects of BPA and other EDCs as well as their molecular mechanism(s) may be useful in sensitizing the scientific community and the manufacturing industry to the importance of finding alternatives to their indiscriminate use.

The effects of in utero bisphenol A exposure on ovarian follicle numbers and steroidogenesis in the F1 and F2 generations of mice

Bisphenol A (BPA) is a commonly used plasticizer. Previous studies show that in utero exposure to BPA affects reproductive outcomes in the F1-F3 generations of mice. However, its multigenerational effects on ovarian histology and steroidogenesis over the reproductive lifespan are unknown. Thus, we tested the hypothesis that BPA has multigenerational effects on follicle numbers and steroidogenesis. Mice were exposed in utero to vehicle control or BPA (0.5, 20, and 50μg/kg/day). Ovaries were collected for histological and gene expression analyses and sera were collected for hormone assays. In utero BPA exposure decreased preantral follicle numbers, cytochrome P450 aromatase mRNA levels, and estradiol levels in the F1 generation, whereas it decreased testosterone levels and altered steroidogenic acute regulatory protein, cytochrome P450 cholesterol side-chain cleavage, 3β-hydroxysteroid dehydrogenase 1, and cytochrome P450 aromatase mRNA levels in the F2 generation. These data suggest that BPA has multigenerational effects on the ovary in mice.

Bisphenol a induces autophagy and apoptosis concurrently involving the Akt/mTOR pathway in testes of pubertal SD rats

Bisphenol A (BPA), a typical endocrine disrupting chemical (EDC), has been proven to cause male reproductive toxicity. However, the precise mechanisms of this effect are still unclear. Puberty is a crucial period of reproductive development, and adolescents are more susceptible to xenobiotics. This research was designed to explore the mechanism of BPA toxicity on pubertal male reproduction. Rats were exposed to 0, 2, 10, 50 mg kg^-1 bw BPA, then the levels of sex hormones, oxidative stress, and semen quality were detected. HE staining, TUNEL assay and transmission electron microscopy were used to investigate the morphological changes, apoptosis, and autophagy in testes, respectively. Expressions of relevant genes and proteins were measured by RT-PCR, western blotting, and immunohistochemical staining. The results indicated that BPA exposure led to oxidative stress and endocrine disorders in pubertal male SD rats, caused apoptosis and autophagy in testes, and then damaged spermatogenesis ultimately. The Akt pathway was activated and the mTOR pathway was inhibited in the process. Taken together, BPA induced apoptosis and autophagy concurrently in pubertal testes, and this added a new layer to our understanding on male reproductive toxicity of BPA. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1977-1989, 2017.

Recent advances in simultaneous analysis of bisphenol A and its conjugates in human matrices: Exposure biomarker perspectives

Human exposures to bisphenol A (BPA) has attained considerable global health attention and represents one of the leading environmental contaminants with potential adverse health effects including endocrine disruption. Current practice of measuring of exposure to BPA includes the measurement of unconjugated BPA (aglycone) and total (both conjugated and unconjugated) BPA; the difference between the two measurements leads to estimation of conjugated forms. However, the measurement of BPA as the end analyte leads to inaccurate estimates from potential interferences from background sources during sample collection and analysis. BPA glucuronides (BPAG) and sulfates (BPAS) represent better candidates for biomarkers of BPA exposure, since they require in vivo metabolism and are not prone to external contamination. In this work, the primary focus was to review the current state of the art in analytical methods available to quantitate BPA conjugates. The entire analytical procedure for the simultaneous extraction and detection of aglycone BPA and conjugates is covered, from sample pre-treatment, extraction, separation, ionization, and detection. Solid phase extraction coupled with liquid chromatograph and tandem mass spectrometer analysis provides the most sensitive detection and quantification of BPA conjugates. Discussed herein are the applications of BPA conjugates analysis in human exposure assessment studies. Measuring these potential biomarkers of BPA exposure has only recently become analytically feasible and there are limitations and challenges to overcome in biomonitoring studies.

Cross-generational effects of parental low dose BPA exposure on the Gonadotropin-Releasing Hormone3 system and larval behavior in medaka (Oryzias latipes)

Growing evidence indicates that chronic exposure to Bisphenol A (BPA) may disrupt normal brain function and behavior mediated by gonadotropin-releasing hormone (GnRH) pathways. Previous studies have shown that low dose BPA (200ng/ml) exposure during embryogenesis altered development of extra-hypothalamic GnRH3 systems and non-reproductive locomotor behavior in medaka. Effects of parental low-dose BPA exposure on the development of GnRH3 systems and locomotor behavior of offspring are not well known. This study examines whether the neurophysiological and behavioral effects of BPA in parents (F0 generation) are carried over to their offspring (F1 generation) using stable transgenic medaka embryos/larvae with GnRH3 neurons tagged with green fluorescent protein (GFP). Parental fish were exposed to BPA (200ng/ml) for either life-long or different developmental time windows. Fertilized F1 eggs were collected and raised in egg/fish water with no environmental exposure to BPA. All experiments were performed on F1 embryos/larvae, which were grouped based on the following parental (F0) BPA exposure conditions - (i) Group 1 (G1): through life; (ii) G2: during embryogenesis and early larval development [1-14days post fertilization (dpf)]; (iii) G3: during neurogenesis (1-5dpf); and (iv) G4: during sex differentiation (5-14dpf). Embryos from unexposed vehicle treated parents served as controls (G0). G1 embryos showed significantly reduced survival rates and delayed hatching time compared to other groups, while G4 embryos hatched significantly earlier than all other groups. At 3 dpf, the GnRH3-GFP intensity was increased by 47% in G3 embryos and decreased in G4 embryos by 59% compared to controls. At 4dpf, G1 fish showed 42% increased intensity, while GFP intensity was reduced by 44% in G3 subjects. In addition, the mean brain size of G1, G3 and G4 embryos were smaller than that of control at 4dpf. At 20dpf, all larvae from BPA-treated parents showed significantly decreased total movement (distance covered) compared with controls, with G2 and G3 fish showing reduced velocity of movement. While at 20 dpf no group differences were seen in the soma diameter of GnRH3-GFP neurons, a 34% decrease in SV2 expression, a marker for synaptic transmission, in G1 larvae was observed. These data suggest that parental BPA exposure during critical windows of embryonic development or chronic treatment affects next-generation offspring both in embryonic and larval brain development as well as larval behavior.

From BPA to its analogues: Is it a safe journey?

Bisphenol-A (BPA) is one of the most abundant synthetic chemicals in the world due to its uses in plastics. Its widespread exposure vis-a-vis low dose effects led to a reduction in its safety dose and imposition of ban on its use in infant feeding bottles. This restriction paved the way for the gradual market entry of its analogues. However, their structural similarity to BPA has put them under surveillance for endocrine disrupting potential. The application of these analogues is increasing and so are the studies reporting their toxicity. This review highlights the reasons which led to the ban of BPA and also reports the exposure and toxicological data available on its analogues. Hence, this compilation is expected to answer in a better way whether the replacement of BPA by these analogues is safer or more harmful?

Not lost in translation: Emerging clinical importance of the G protein-coupled estrogen receptor GPER

It has been 20years that the G protein-coupled estrogen receptor (GPER) was cloned as the orphan receptor GPR30 from multiple cellular sources, including vascular endothelial cells. Here, I will provide an overview of estrogen biology and the historical background leading to the discovery of rapid vascular estrogen signaling. I will also review the recent advances in the understanding of the mechanisms underlying GPER function, its role in physiology and disease, some of the currently available GPER-targeting drugs approved for clinical use such as SERMs (selective estrogen receptor modulators) and SERDs (selective estrogen receptor downregulators). Many of currently used drugs such as tamoxifen, raloxifene, or faslodex™/fulvestrant were discovered targeting GPER many years after they had been introduced to the clinics for entirely different purposes. This has important implications for the clinical use of these drugs and their modes of action, which I have termed 'reverse translational medicine'. In addition, environmental pollutants known as 'endocrine disruptors' have been found to bind to GPER. This article also discusses recent evidence in these areas as well as opportunities in translational clinical medicine and GPER research, including medical genetics, personalized medicine, prevention, and its theranostic use.

Patterns, Variability, and Predictors of Urinary Bisphenol A Concentrations during Childhood

We examined the patterns, variability, and predictors of urinary bisphenol A (BPA) concentrations in 337 children from the Cincinnati, Ohio HOME Study. From 2003 to 2014, we collected two urine samples from women at 16 and 26 weeks of pregnancy and six urine samples from children at 1-5 and 8 years of age. We used linear mixed models to calculate intraclass correlation coefficients (ICCs) as a measure of within-person BPA variability and to identify sociodemographic and environmental predictors. For the 8-year visit, we used multivariable linear regression to explore associations between urinary BPA concentrations and exposure-related factors. We calculated daily intakes using equations estimating creatinine excretion rates and creatinine-standardized BPA concentrations. Urinary BPA concentrations, which decreased over childhood, had a low degree of reproducibility (ICC < 0.2). Estimated daily intakes decreased with age and were below the reference dose of 50 μg/kg body weight/day. BPA concentrations were positively associated with consuming food stored or heated in plastic, consuming canned food and beverages, and handling cash register receipts. Our results suggest that there are multiple sources of BPA exposure in young children. Etiological studies should collect serial urine samples to accurately classify BPA exposure and consider sociodemographic and environmental factors as possible confounders.

Bisphenol A Induces Migration through a GPER-, FAK-, Src-, and ERK2-Dependent Pathway in MDA-MB-231 Breast Cancer Cells

Bisphenol A (BPA) is an industrial synthetic chemical utilized in the production of numerous products including food and beverage containers. Humans are exposed to BPA during ingestion of contaminated water and food because it can leach from polycarbonate containers, beverage cans, and epoxy resins. BPA has been related with the development of several diseases including breast cancer. However, the signal transduction pathways mediated by BPA and its role as a promoter of migration and invasion in breast cancer cells remain to be investigated. Here, we demonstrate that BPA promotes migration, invasion, and an increase in the number of focal contacts in MDA-MB-231 breast cancer cells. Moreover, MDA-MB-231 cells express GPER, and BPA promotes migration through a GPER-dependent pathway. BPA also induces activation of FAK, Src, and ERK2, whereas migration induced by BPA requires the activity of these kinases. In addition, BPA induces an increase on AP-1- and NFκB-DNA binding activity through an Src- and ERK2-dependent pathway. In conclusion, our findings demonstrate, that BPA induces the activation of signal transduction pathways, which mediate migration, AP-1/NFκB-DNA binding activity, and an invasion process in MDA-MB-231 breast cancer cells.

The effects of in utero bisphenol A exposure on the ovaries in multiple generations of mice

Bisphenol A is used in polycarbonate plastics and epoxy resins. Previous studies show that in utero BPA exposure inhibits germ cell nest breakdown in the F1 generation of mice, but its effects on germ cell nest breakdown and on the ovary in the F2-F3 generations were unknown. Thus, we tested the hypothesis that BPA has transgenerational effects on the ovary. Mice were exposed to BPA in utero (BPA 0.5, 20, or 50μg/kg/day), and ovaries were collected at postnatal days (PND) 4 and 21 from the F1-F3 generations and subjected to histological evaluation and gene expression analyses. In utero BPA exposure did not have transgenerational effects on germ cell nest breakdown and gene expression on PND 4, but it caused transgenerational changes in expression in multiple genes on PND 21. Collectively, these data indicate that in utero BPA exposure has some transgenerational effects in mice.

Low dose exposure to Bisphenol A alters development of gonadotropin-releasing hormone 3 neurons and larval locomotor behavior in Japanese Medaka

Accumulating evidence indicates that chronic low dose exposure to Bisphenol A (BPA), an endocrine disruptor, may disrupt normal brain development and behavior mediated by the gonadotropin-releasing hormone (GnRH) pathways. While it is known that GnRH neurons in the hypothalamus regulate reproductive physiology and behavior, functional roles of extra-hypothalamic GnRH neurons remain unclear. Furthermore, little is known whether BPA interacts with extra-hypothalamic GnRH3 neural systems in vulnerable developing brains. Here we examined the impact of low dose BPA exposure on the developing GnRH3 neural system, eye and brain growth, and locomotor activity in transgenic medaka embryos and larvae with GnRH3 neurons tagged with GFP. Fertilized eggs were collected daily and embryos/larvae were chronically exposed to 200ng/ml of BPA, starting at 1 day post fertilization (dpf). BPA significantly increased fluorescence intensity of the GnRH3-GFP neural population in the terminal nerve (TN) of the forebrain at 3dpf, but decreased the intensity at 5dpf, compared with controls. BPA advanced eye pigmentation without affecting eye and brain size development, and accelerated times to hatch. Following chronic BPA exposure, 20dpf larvae showed suppression of locomotion, both in distance covered and speed of movement (47% and 43% reduction, respectively). BPA-induced hypoactivity was accompanied by decreased cell body sizes of individual TN-GnRH3 neurons (14% smaller than those of controls), but not of non-GnRH3 neurons. These novel data demonstrate complex neurobehavioral effects of BPA on the development of extra-hypothalamic GnRH3 neurons in teleost fish.

Bisphenol A exposure pathways in early childhood: Reviewing the need for improved risk assessment models

Bisphenol A (BPA) is a plasticiser found in a number of household plastics, electronics, and food-packaging materials. Over the past 5 years, several human epidemiological studies have reported a positive association between BPA exposure and adverse health outcomes in children, including obesity, asthma, preterm birth, and neuro-behavioural disturbances. These findings are in conflict with international environmental risk assessment models, which predict daily exposure levels to BPA should not pose a risk to child health. The aim of this review is to provide an overview of the evidence for different exposure sources and potential exposure pathways of BPA in early childhood. By collating the findings from experimental models and exposure associations observed in human bio-monitoring studies, we affirm the potential for non-dietary sources to make a substantial contribution to total daily exposure in young children. Infants and toddlers have distinctive exposure sources, physiology, and metabolism of endocrine-disrupting chemicals. We recommend risk-assessment models implement new frameworks, which specifically address exposure and hazard in early childhood. This is particularly important for BPA, which is present in numerous products in the home and day-care environments, and for which animal studies report contradictory findings on its safety at environmentally relevant levels of exposure.

Developmental Exposure to Environmental Toxicants

Children interact with the physical environment differently than adults, and are uniquely susceptible to environmental toxicants. Routes of absorption, distribution, metabolism, and target organ toxicities vary as children grow and develop. This article summarizes the sources of exposure and known adverse effects of toxicants that are ubiquitous in our environment, including tobacco smoke, ethanol, solvents, heavy metals, volatile organic compounds, persistent organic pollutants, and pesticides. Preventive strategies that may be used in counseling children and their families are highlighted.