Putative environmental-endocrine disruptors and obesity: a review

Role of Thymus ciliatus (Thyme) to Ameliorate the Acute Neurotoxicity Induced by Bisphenol A: In Vivo Supported with Virtual Study

Background/Objectives: The purpose of this research was to investigate the effects of bisphenol A (BPA) exposure on neurobehavioral testing in young Wistar rats and to evaluate the therapeutic potential of Thymus ciliatus (TEO) essential oil to attenuate the damage induced by this chemical toxin. Methods: The essential oil was extracted by hydro-distillation (yield of 2.26%), and the characterization by GC-MS indicates that the major components of Thymus ciliatus oil are thymol (63.33%), p-cymene (13.4%), and σ-terpinene (6.69%). Acute BPA intoxication was induced with a dose of 50 mg/kg orally for 60 days. The neurobehavioral evaluation, performed using a comprehensive set of tests including the forced swim test, dark/light box, Morris water maze, open field test, and sucrose preference test, clearly demonstrated that bisphenol A (BPA) exposure induced significant neurobehavioral impairments. Results: These impairments included reduced exploratory behavior indicative of heightened stress, anxiety, and depressive-like states, as well as deficits in memory and learning. Furthermore, BPA intoxication was associated with metabolic disturbances such as hyperglycemia along with histopathological evidence of brain tissue damage. However, TEO treatment attenuated these adverse effects by restoring neurobehavioral function. Molecular docking analysis revealed an affinity between the major essential oils identified in T. ciliatus, BPA, and the 5HT2C receptor and the MAO, AChE, and BChE enzymes, suggesting a potential mechanism underlying BPA's effects on behavior and memory. In addition, TEO also showed an interaction with these molecules, suggesting a therapeutic potential against BPA. These findings underscore the promising role of TEO in mitigating the poisonous effects of BPA and pave the way for additional research into the molecular mechanisms and therapeutic uses of natural bioactive compounds for the prevention and treatment of toxic diseases. Thymol, the major compound in TEO, exhibited activity related to the dopamine and serotonin pathways, so it could have potential antidepressant properties. Conclusions: Thymol might be a promising candidate for the treatment of neurodegenerative and neurological disorders such as depression, Parkinson's disease, and Alzheimer's disease while also preventing histological damage in the brain.

Early-life exposures to phenols, parabens and phthalates and fat mass at 3 years of age in the SEPAGES cohort

BACKGROUND

Early-life exposure to short half-life chemicals may influence adiposity growth, a precursor to obesity. Previous studies often relied on limited urine samples that inadequately represent exposure during pregnancy or infancy. Additionally, childhood adiposity is commonly estimated using body mass index, which does not accurately reflect body composition. We aimed to investigate associations between early-life exposures to phenols, parabens, phthalates and fat mass percent at 3 years of age among 341 mother-child couple from the SEPAGES cohort. We further assessed potential effect modification by sex.

METHODS

We measured 8 phenols, 4 parabens, 13 phthalates and 2 non-phthalate plasticizer metabolites from weekly pooled urine sample collected from mothers during pregnancy (three urine samples a day, median 18 and 34 gestational weeks), and from their infant (one urine sample a day, at 2 and 12 months). Clinical examinations at 3 years included standardized skinfold thickness measurements and bioelectrical impedance analysis to calculate fat mass percentage.

RESULTS

Positive associations were identified between prenatal exposures to bisphenol S, mono-benzyl phthalate (MBzP), monoethyl phthalate (MEP), and mono-n-butyl phthalate and fat mass percentage at 3 years, while triclosan showed a negative association. MBzP and MEP showed effect modification by sex, with stronger associations among females. No significant associations were detected for postnatal exposures.

CONCLUSION

This study suggests associations between prenatal exposures to short half-life chemicals and percent fat mass in preschool children. Furthermore, this study is the first investigating the impact of prenatal bisphenol S exposure, highlighting the need for investigation of this overlooked compound.

Plastic additives affect estrogenic pathways and lipid metabolism in precision - cut - liver slices in Atlantic cod (Gadus morhua)

The overall aim of the present study was to determine if exposure to three high volume plastic additives, including diethylhexyl phthalate (DEHP), bisphenol A (BPA) and benzotriazoles (BT), have the potential to promote adverse effects in Atlantic cod (G. morhua). Ex vivo precision cut - liver slices (PCLS) from six male juvenile Atlantic cod were exposed to four concentrations of mono-(2-ethylhexyl)-phthalate (MEHP, the main metabolite of DEHP), BPA and BT both singly and in mixtures ranging from 0.1 to 100 μM (MEHP), 0.022-22 μM (BPA) and 0.042-42 μM (BT). Histology and transmission electron microscopy (TEM) were used to assess pathological changes and ultrastructure of the exposed liver tissue. Vitellogenin (Vtg) produced by the hepatic tissue was analyzed using ELISA, and the transcription levels of selected biomarker genes (vtg1, esr1, cyp1a, scdb, aclya, fabp1a, acox1, hnf4a and cebp) were measured using Quantitative real-time polymerase chain reaction (Q-PCR). An estrogenic effect was observed with a significant upregulation of the vtg1 and esr1 genes and increase in Vtg protein synthesis following exposure to BPA and a mixture of the selected compounds. The hnf4a showed a significant downregulation following mixture exposure, where the BPA was suspected to be the main driver for this response although not inducing a significant downregulation in the single component exposure. There was no significant difference between the mixture exposure and the individual compound exposures, nevertheless a tendency of an antagonistic mixture effect for the biomarkers of estrogenic effect (vtg1, esr1 and Vtg), and possibly synergistic or additive effect on the lipid metabolism related gene hnf4a, warrants further investigation.

A simple action reduces high fat diet intake and obesity in mice

Diets that are high in fat cause over-eating and weight gain in multiple species of animals, suggesting that high dietary fat is sufficient to cause obesity. However, high-fat diets are typically provided freely to animals in obesity experiments, so it remains unclear if high-fat diets would still cause obesity if they required more effort to obtain. We hypothesized that unrestricted and easy access is necessary for high-fat diet induced over-eating, and the corollary that requiring mice to perform small amounts of work to obtain high-fat diet would reduce high-fat diet intake and associated weight gain. To test this hypothesis, we developed a novel home-cage based feeding device that either provided high-fat diet freely, or after mice poked their noses into a port one time - a simple action that is easy for them to do. We tested the effect of this intervention for six weeks, with mice receiving all daily calories from high-fat diet, modifying only how they accessed it. Requiring mice to nose-poke to access high-fat diet reduced intake and nearly completely prevented the development of obesity. In follow up experiments, we observed a similar phenomenon in mice responding for low-fat grain-based pellets that do not induce obesity, suggesting a general mechanism whereby animals engage with and consume more food when it is freely available vs. when it requires a simple action to obtain. We conclude that unrestricted access to food promotes overeating, and that a simple action such as a nose-poke can reduce over-eating and weight gain in mice. This may have implications for why over-eating and obesity are common in modern food environments, which are often characterized by easy access to low-cost unhealthy foods.

Modulation of adipogenesis and lipogenesis by indomethacin and pantoprazole

Endocrine disruptors are suggested to act as potential "obesogens" by interacting with various metabolic processes in adipose tissue. Besides industrial chemicals that are blamed for acting as endocrine disruptors as well as obesogens, pharmaceuticals can also cause obesogenic effects as unintended adverse effects. However, limited studies evaluated the obesogenic adverse effects of pharmaceuticals. Based on this information, the present study aimed to investigate the possible in vitro adipogenic/lipogenic potential of indomethacin and pantoprazole that are prescribed during pregnancy. Their effects on lipid accumulation, adiponectin level, glycerol-3-phosphate dehydrogenase (G3PDH) activity, and expression of adipogenic genes and proteins were investigated in 3 T3-L1 cell line. The range of concentrations of the pharmaceuticals was selected according to their Cmax values. Lipid accumulation was increased dependently with indomethacin dose and with pantoprazole at its highest concentration. Both pharmaceuticals also increased adiponectin levels, which was thought to play a role in stimulating the adipogenesis pathway. Moreover, both pharmaceuticals altered the gene and/or protein expression of some adipogenic/lipogenic transcriptional factors, which may lead to disruption of metabolic pathways during the fetal period. In conclusion, indomethacin and pantoprazole may have obesogenic effects through different mechanisms and their potential to cause obesity should be investigated by further in vivo and epidemiological studies.

Fetal and Infancy Exposure to Phenols, Parabens, and Phthalates and Anthropometric Measurements up to 36 Months, in the Longitudinal SEPAGES Cohort

BACKGROUND

Endocrine-disrupting chemicals may play a role in adiposity development during childhood. Until now literature in this scope suffers from methodologic limitations in exposure assessment using one or few urine samples and missing assessment during the infancy period.

OBJECTIVES

We investigated the associations between early-life exposure to quickly metabolized chemicals and post-natal growth, relying on repeated within-subject urine collections over pregnancy and infancy.

METHODS

We studied the associations of four phenols, four parabens, seven phthalates, and one nonphthalate plasticizer from weekly pooled urine samples collected from the mother during second and third trimesters (median 18 and 34 gestational weeks, respectively) and infant at 2 and 12 months of age, and child growth until 36 months. We relied on repeated measures of height, weight and head circumference from study visits and the child health booklet to predict growth outcomes at 3 and 36 months using the Jenss-Bayley nonlinear mixed model. We assessed associations with individual chemicals using adjusted linear regression and mixtures of chemicals using a Bayesian kernel machine regression model.

RESULTS

The unipollutant analysis revealed few associations. Bisphenol S (BPS) at second trimester was positively associated with all infant growth parameters at 3 and 36 months, with similar patterns between exposure at third trimester and all infant growth parameters at 3 months. Mono-n-butyl phthalate (MnBP) at 12 months was positively associated with body mass index (BMI), weight, and head circumference at 36 months. Mixture analysis revealed positive associations between exposure at 12 months and BMI and weight at 36 months, with MnBP showing the highest effect size within the mixture.

CONCLUSIONS

This study suggests that exposure in early infancy may be associated with increased weight and BMI in early childhood, which are risk factors of obesity in later life. Furthermore, this study highlighted the impact of BPS, a compound replacing bisphenol A, which has never been studied in this context. https://doi.org/10.1289/EHP13644.

Prenatal Phenol and Paraben Exposures and Adverse Birth Outcomes: A Prospective Analysis of U.S. Births

BACKGROUND

Synthetic chemicals are increasingly being recognized for potential independent contributions to preterm birth (PTB) and low birth weight (LBW). Bisphenols, parabens, and triclosan are consumer product chemicals that act via similar mechanisms including estrogen, androgen, and thyroid disruption and oxidative stress. Multiple cohort studies have endeavored to examine effects on birth outcomes, and systematic reviews have been limited due to measurement of 1-2 spot samples during pregnancy and limited diversity of populations.

OBJECTIVE

To study the effects of prenatal phenols and parabens on birth size and gestational age (GA) in 3,619 mother-infant pairs from 11 cohorts in the NIH Environmental influences on Child Health Outcomes program.

RESULTS

While many associations were modest and statistically imprecise, a 1-unit increase in log10 pregnancy averaged concentration of benzophenone-3 and methylparaben were associated with decreases in birthweight, birthweight adjusted for gestational age and SGA. Increases in the odds of being SGA were 29% (95% CI: 5%, 58%) and 32% (95% CI: 3%, 70%), respectively. Bisphenol S in third trimester was also associated with SGA (OR 1.52, 95% CI 1.08, 2.13). Associations of benzophenone-3 and methylparaben with PTB and LBW were null. In addition, a 1-unit increase in log10 pregnancy averaged concentration of 2,4-dichlorophenol was associated with 43% lower (95% CI: -67%, -2%) odds of low birthweight; the direction of effect was the same for the highly correlated 2,5-dichlorophenol, but with a smaller magnitude (-29%, 95% CI: -53%, 8%).

DISCUSSION

In a large and diverse sample generally representative of the United States, benzophenone-3 and methylparaben were associated with lower birthweight as well as birthweight adjusted for gestational age and higher odds of SGA, while 2,4-dichlorophenol. These associations with smaller size at birth are concerning in light of the known consequences of intrauterine growth restriction for multiple important health outcomes emerging later in life.

3-tert-Butyl-4-hydroxyanisole perturbs renal lipid metabolism in vitro by targeting androgen receptor-regulated de novo lipogenesis

The widespread usage of 3-tert-butyl-4-hydroxyanisole (3-BHA) as an anthropogenic antioxidant has caused considerable environmental contamination and frequent detection in diverse human-derived samples. 3-BHA can promote adipogenesis and impair hepatic lipid metabolism, while its effects on renal lipid homeostasis remain to be uncertain. Herein, using the human kidney 2 (HK-2) cell experiments, 3-BHA was found to cause a significant reduction in lipid accumulation of the HK-2 cells in both exposure concentration- and duration-dependent manners. Exposure to 3-BHA lowered the transcriptional expressions of sterol regulatory element-binding protein 1 (SREBP1) and acetyl-CoA carboxylase (ACC), as well as ACC activity, indicating the inhibition in the process of de novo lipogenesis in HK-2 cells. On this basis, the mechanism study suggested that the reduced glucose absorption and accelerated glycolysis were concomitantly involved. The antagonism of 3-BHA on the transactivation of androgen receptor (AR) contributed to the lowered de novo lipogenesis and the consequent intracellular lipid reduction. The metabolomics data further confirmed the imbalance of lipid homeostasis and dysregulation of de novo lipogenesis. The new findings on the impaired renal lipid metabolism induced by 3-BHA warranted proper care about the usage of this chemical as a food additive.

A Systematic Review on the Association between Obesity and Mood Disorders and the Role of Gut Microbiota

Obesity is a complex health condition that increases the susceptibility to developing cardiovascular diseases, diabetes, and numerous other metabolic health issues. The effect of obesity is not just limited to the conditions mentioned above; it is also seen to have a profound impact on the patient’s mental state, leading to the onset of various mental disorders, particularly mood disorders. Therefore, it is necessary to understand the mechanism underlying the crosstalk between obesity and mental disorders. The gut microbiota is vital in regulating and maintaining host physiology, including metabolism and neuronal circuits. Because of this newly developed understanding of gut microbiota role, here we evaluated the published diverse information to summarize the achievement in the field. In this review, we gave an overview of the association between obesity, mental disorders, and the role of gut microbiota there. Further new guidelines and experimental tools are necessary to understand the microbial contribution to regulate a balanced healthy life.

Vitamin D ameliorates liver pathology in mice caused by exposure to endocrine disruptor bisphenol A

Background

Increasing evidence suggests that bisphenol A (BPA) induces liver pathological changes. Further, an association between BPA and circulating vitamin D (VitD) levels were documented.

Aim

The role of VitD in BPA-induced liver pathological changes was explored in this study.

Methods

Healthy 4.5-week-old male (n = 35) and female (n = 35) Swiss albino mice were used in this study. The animals were randomly divided into control and treated groups. The control groups were further divided into sham (no treatment) and vehicle (corn oil), whereas the treated groups were also divided into VitD (2195 U/kg), BPA (50 μg/kg), and BPA + VitD (50 μg/kg + 2195 U/kg) groups. For 6 weeks (twice a week), the animals were dosed intraperitoneally. One week later (at 10.5-weeks-old), the animals were sacrificed for biochemical and histological analyses.

Results

BPA produced a considerable rise in the body and liver weights in both genders of mice when compared to control mice. BPA also caused significant increases in the liver damage markers alanine transaminase (ALT), alkaline phosphatase (ALP), and gamma-glutamyl transferase (GGT). It also induced liver histopathological changes, including higher apoptotic indices in both genders. On the other hand, treatment with VitD considerably reduced liver damage and slightly decreased the apoptotic index rate. The ALP, ALT, and GGT levels were also markedly reduced. VitD has been proven to have a protective effect on both genders.

Conclusions

According to our findings, VitD protects mice from BPA-induced liver damage, possibly via suppressing liver damage markers.

Modification of Cotton Fabric with Molecularly Imprinted Polymer-Coated Carbon Dots as a Sensor for 17 α-methyltestosterone

Molecularly imprinted polymers@ethylenediamine-modified carbon dots grafted on cotton fabrics (MIPs@EDA-CDs/CF) and smartphone-based fluorescence image analysis were proposed and used for the first time for the detection of 17 α-methyltestosterone (MT). The EDA-CDs were synthesized and grafted on cotton fabric before coating with the MIPs. The MIPs were synthesized using the MT as a template molecule, methacrylic acid (MAA) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker, and azobisisobutyronitrile (AIBN) as an initiator. The MIPs@EDA-CDs/CF were characterized using FTIR, SEM-EDS, and RGB fluorescence imaging. The fluorescence images were also taken using a smartphone and the ImageJ program was used for RGB measurement. The Δ red intensity was linearly proportional to MT concentration in the range of 100 to 1000 μg/L (R2 = 0.999) with a detection limit of 44.4 μg/L and quantification limit of 134 μg/L. The MIPs@EDA-CDs/CF could be stored at 4 °C for a few weeks and could be reused twice. The proposed method could apply for the specific determination of MT in water and sediment samples along with satisfactory recoveries of 96-104% and an acceptable relative standard deviation of 1-6% at the ppb level.

Bisphenol A: Potential Factor of Miscarriage in Women in the Context of the Phenomenon of Neutrophil Extracellular Traps

Humans are exposed to a number of environmental pollutants every day. Among them, endocrine disruptors are particularly harmful to human health. Bisphenol A (BPA) is a xenoestrogen that has been shown to disrupt the endocrine system and cause reproductive toxicity. In this study, we aimed to verify the potential relationship between BPA and miscarriage involving the formation of neutrophil extracellular traps (NETs). Blood samples were collected from healthy women and women who had miscarriage in the first trimester of pregnancy. The serum levels of cytoplasmic anti-PR3 antibody and perinuclear anti-MPO antibody were determined using an immunoenzymatic method. The concentrations of key proinflammatory proteins TNF-α and MCP-1, as well as NADPH oxidase subunits NOX1 and NCF2, were also measured in the serum samples. The serum concentration of BPA was determined using gas chromatography. The results showed that the concentrations of BPA were significantly elevated in the serum of women who had miscarriage compared to the control group, with the highest concentration found in the “NETs-positive” group. The levels of MCP-1 and TNF-α were significantly higher in the “NETs-positive” group compared to the “NETs-negative” and control group. The levels of NOX1 and NCF2 were also higher in the “NETs-positive” group compared to the “NETs-negative” group. The study showed that BPA could play a role in the course of miscarriage through the formation of NETs. The results indicate the need to limit the exposure of women planning pregnancy to xenoestrogens, including BPA.

Histone deacetylase 2 inhibitor valproic acid attenuates bisphenol A-induced liver pathology in male mice

Accumulating evidence indicates the role of endocrine disruptor bisphenol A (BPA) in many pathological conditions. Histone deacetylase (HDAC) inhibition has potential for the treatment of many diseases/abnormalities. Using a mouse BPA exposure model, this study investigated the hepatoprotective effects of the Food and Drug Administration–approved HDAC2 inhibitor valproic acid (VPA) against BPA-induced liver pathology. We randomly divided 30 adult male Swiss albino mice (8 weeks old; N = 6) into five groups: group 1, no treatment (sham control (SC)); group 2, only oral sterile corn oil (vehicle control (VC)); group 3, 4 mg/kg/day of oral BPA (single dose (BPA group)); group 4, 0.4% oral VPA (VPA group); and group 5, oral BPA + VPA (BPA + VPA group). At the age of 10 weeks, the mice were euthanized for biochemical and histological examinations. BPA promoted a significant decrease in the body weight (BW), an increase in the liver weight, and a significant increase in the levels of liver damage markers aspartate aminotransferase and alanine aminotransferase in the BPA group compared to SC, as well as pathological changes in liver tissue. We also found an increase in the rate of apoptosis among hepatocytes. In addition, BPA significantly increased the levels of oxidative stress indices, malondialdehyde, and protein carbonylation but decreased the levels of reduced glutathione (GSH) in the BPA group compared to SC. In contrast, treatment with the HDAC2 inhibitor VPA significantly attenuated liver pathology, oxidative stress, and apoptosis and also enhanced GSH levels in VPA group and BPA + VPA group. The HDAC2 inhibitor VPA protects mice against BPA-induced liver pathology, likely by inhibiting oxidative stress and enhancing the levels of antioxidant-reduced GSH.

ER/AR Multi-Conformational Docking Server: A Tool for Discovering and Studying Estrogen and Androgen Receptor Modulators

The prediction of the estrogen receptor (ER) and androgen receptor (AR) activity of a compound is quite important to avoid the environmental exposures of endocrine-disrupting chemicals. The Estrogen and Androgen Receptor Database (EARDB, http://eardb.schanglab.org.cn/) provides a unique collection of reported ERα, ERβ, or AR protein structures and known small molecule modulators. With the user-uploaded query molecules, molecular docking based on multi-conformations of a single target will be performed. Moreover, the 2D similarity search against known modulators is also provided. Molecules predicted with a low binding energy or high similarity to known ERα, ERβ, or AR modulators may be potential endocrine-disrupting chemicals or new modulators. The server provides a tool to predict the endocrine activity for compounds of interests, benefiting for the ER and AR drug design and endocrine-disrupting chemical identification.

Exposure to air pollutant mixture and gestational diabetes mellitus in Southern California: Results from electronic health record data of a large pregnancy cohort

BACKGROUND

Epidemiological findings are inconsistent regarding the associations between air pollution exposure during pregnancy and gestational diabetes mellitus (GDM). Several limitations exist in previous studies, including potential outcome and exposure misclassification, unassessed confounding, and lack of simultaneous consideration of air pollution mixtures and particulate matter (PM) constituents.

OBJECTIVES

To assess the association between GDM and maternal residential exposure to air pollution, and the joint effect of the mixture of air pollutants and PM constituents.

METHODS

Detailed clinical data were obtained for 395,927 pregnancies in southern California (2008-2018) from Kaiser Permanente Southern California (KPSC) electronic health records. GDM diagnosis was based on KPSC laboratory tests. Monthly average concentrations of fine particulate matter < 2.5 μm (PM_2.5), <10 μm (PM₁₀), nitrogen dioxide (NO₂), and ozone (O₃) were estimated using kriging interpolation of Environmental Protection Agency's routine monitoring station data, while PM_2.5 constituents (i.e., sulfate, nitrate, ammonium, organic matter and black carbon) were estimated using a fine-resolution geoscience-derived model. A multilevel logistic regression was used to fit single-pollutant models; quantile g-computation approach was applied to estimate the joint effect of air pollution and PM component mixtures. Main analyses adjusted for maternal age, race/ethnicity, education, median family household income, pre-pregnancy BMI, smoking during pregnancy, insurance type, season of conception and year of delivery.

RESULTS

The incidence of GDM was 10.9% in the study population. In single-pollutant models, we observed an increased odds for GDM associated with exposures to PM_2.5, PM₁₀, NO₂ and PM_2.5 constituents. The association was strongest for NO₂ [adjusted odds ratio (OR) per interquartile range: 1.176, 95% confidence interval (CI): 1.147-1.205)]. In multi-pollutant models, increased ORs for GDM in association with one quartile increase in air pollution mixtures were found for both kriging-based regional air pollutants (NO₂, PM_2.5, and PM₁₀, OR = 1.095, 95% CI: 1.082-1.108) and PM_2.5 constituents (i.e., sulfate, nitrate, ammonium, organic matter and black carbon, OR = 1.258, 95% CI: 1.206-1.314); NO₂ (78%) and black carbon (48%) contributed the most to the overall mixture effects among all krigged air pollutants and all PM_2.5 constituents, respectively. The risk of GDM associated with air pollution exposure were significantly higher among Hispanic mothers, and overweight/obese mothers.

CONCLUSION

This study found that exposure to a mixture of ambient PM_2.5, PM₁₀, NO₂, and PM_2.5 chemical constituents was associated with an increased risk of GDM. NO₂ and black carbon PM_2.5 contributed most to GDM risk.

Prenatal exposure to persistent organic pollutants and childhood obesity: A systematic review and meta-analysis of human studies

We conducted a systematic review and meta-analysis of the associations between prenatal exposure to persistent organic pollutants (POPs) and childhood obesity. We focused on organochlorines (dichlorodiphenyltrichloroethane [DDT], dichlorodiphenyldichloroethylene [DDE], hexachlorobenzene [HCB], and polychlorinated biphenyls [PCBs]), perfluoroalkyl and polyfluoroalkyl substances (PFAS), and polybrominated diphenyl ethers (PBDEs) that are the POPs more widely studied in environmental birth cohorts so far. We search two databases (PubMed and Embase) through July/09/2021 and identified 33 studies reporting associations with prenatal organochlorine exposure, 21 studies reporting associations with prenatal PFAS, and five studies reporting associations with prenatal PBDEs. We conducted a qualitative review. Additionally, we performed random-effects meta-analyses of POP exposures, with data estimates from at least three prospective studies, and BMI-z. Prenatal DDE and HCB levels were associated with higher BMI z-score in childhood (beta: 0.12, 95% CI: 0.03, 0.21; I2 : 28.1% per study-specific log increase of DDE and beta: 0.31, 95% CI: 0.09, 0.53; I2 : 31.9% per study-specific log increase of HCB). No significant associations between PCB-153, PFOA, PFOS, or pentaPBDEs with childhood BMI were found in meta-analyses. In individual studies, there was inconclusive evidence that POP levels were positively associated with other obesity indicators (e.g., waist circumference).

Influence of BPA exposure, measured in saliva, on childhood weight

INTRODUCTION

Endocrine disruptors such as bisphenol A (BPA), BPA glycidyl methacrylate, and other BPA acrylate-based derivatives have been related to type 2 diabetes, the metabolic syndrome, and obesity, among other metabolic disorders. The objective of this study is to examine the influence of BPA exposure by saliva analysis and daily physical activity on the risk of overweight/obesity in schoolchildren from southern Spain.

METHODS

The study included 300 children (53.5% girls) aged 7-10 years. Participants completed a questionnaire with four sections: participant data, including demographic information and life and family habits; semi-quantitative food frequency questionnaire; anthropometric variables; and physical activity variables. All participants underwent dental examination, when the presence of sealants/composites in each tooth and other dental alterations was recorded, and samples of whole saliva were collected for UHPLC-MS/MS analyses.

RESULTS

Risk of overweight/obesity was significantly influenced by body fat composition (OR = 10.77), not walking to and from school (OR = 1.38), lesser energy expenditure in sedentary activities (OR = 12.71), greater energy expenditure in sports (OR =1.62), and exposure to BPA from dental sealants/composites (OR = 1.38; p = 0.058).

DISCUSSION

Further research is warranted on this issue in children, who may be especially vulnerable to the negative health effects of endocrine disruption.

Untargeted Metabolomics Analysis Revealed Lipometabolic Disorders in Perirenal Adipose Tissue of Rabbits Subject to a High-Fat Diet

Simply Summary

A high-fat diet is widely recognized as a significant modifiable risk for metabolic diseases. In this study, untargeted metabolomics, combined with liquid chromatography and high-resolution mass spectrometry, was used to evaluate perirenal adipose tissue metabolic changes. Our study revealed 206 differential metabolites. These metabolites were mainly associated with the biosynthesis of unsaturated fatty acids, the arachidonic acid metabolic pathway, the ovarian steroidogenesis pathway, and the platelet activation pathway. Our study revealed that a high-fat diet causes significant lipometabolic disorders; these metabolites may inhibit oxygen respiration by increasing adipocytes cells and density, cause mitochondrial and endoplasmic reticulum dysfunction, produce inflammation, and finally lead to insulin resistance, thereby increasing the risk of Type 2 diabetes, atherosclerosis, and other metabolic syndromes.

Abstract

A high-fat diet (HFD) is widely recognized as a significant modifiable risk for insulin resistance, inflammation, Type 2 diabetes, atherosclerosis and other metabolic diseases. However, the biological mechanism responsible for key metabolic disorders in the PAT of rabbits subject to HFD remains unclear. Here, untargeted metabolomics (LC-MS/MS) combined with liquid chromatography (LC) and high-resolution mass spectrometry (MS) were used to evaluate PAT metabolic changes. Histological observations showed that the adipocytes cells and density of PAT were significantly increased in HFD rabbits. Our study revealed 206 differential metabolites (21 up-regulated and 185 down-regulated); 47 differential metabolites (13 up-regulated and 34 down-regulated), comprising mainly phospholipids, fatty acids, steroid hormones and amino acids, were chosen as potential biomarkers to help explain metabolic disorders caused by HFD. These metabolites were mainly associated with the biosynthesis of unsaturated fatty acids, the arachidonic acid metabolic pathway, the ovarian steroidogenesis pathway, and the platelet activation pathway. Our study revealed that a HFD caused significant lipometabolic disorders. These metabolites may inhibit oxygen respiration by increasing the adipocytes cells and density, cause mitochondrial and endoplasmic reticulum dysfunction, produce inflammation, and finally lead to insulin resistance, thus increasing the risk of Type 2 diabetes, atherosclerosis, and other metabolic syndromes.

Vitamin D mitigates adult onset diseases in male and female mice induced by early-life exposure to endocrine disruptor BPA

Background

During early development, environmental compounds can induce adult onset diseases and disrupt the circulating vitamin D (VitD) levels.

Aim

This study aimed to examine the protective role of VitD against the adverse effects of BPA on male and female mice.

Methods

A total of 60 male and female Swiss Albino mice (3 weeks old) were randomly divided into 5 groups; each consisted of 12 mice (6 males and 6 females) and was treated as follows: Group I received no treatment (sham control); Group II, sterile corn oil only (vehicle control); Group III, BPA (400 μg/kg); Group IV, VitD (2,195 IU/kg); and Group V, BPA + VitD. At 10.5 weeks, the animals were sacrificed to conduct histological examinations.

Results

BPA-exposed mice were found to have neurobehavioral abnormalities, heart, kidney, and lung diseases with increased apoptotic indices in both sexes. On the other hand, the treatment of BPA mice with VitD altered this scenario with modulated motor activity, enhanced body and organ weights, and preserved the heart, kidney, and lung architecture, alongside a decreased percent apoptotic index.

Conclusion

Our findings illustrate that VitD protects mice against BPA-induced heart, kidney, and lung abnormalities.

Endocrine-Disrupting Chemicals and Early Puberty in Girls

In recent decades, pubertal onset in girls has been considered to occur at an earlier age than previously. Exposure to endocrine-disrupting chemicals (EDCs) has been associated with alterations in pubertal timing, with several reports suggesting that EDCs may have a role in the secular trend in pubertal maturation, at least in girls. However, relevant studies give inconsistent results. On the other hand, the majority of girls with idiopathic precocious or early puberty present the growth pattern of constitutional advancement of growth (CAG), i.e., growth acceleration soon after birth. Herein, we show that the growth pattern of CAG is unrelated to exposure to endocrine-disrupting chemicals and is the major determinant of precocious or early puberty. Presented data suggest that EDCs, at most, have a minor effect on the timing of pubertal onset in girls.

Maternal exposure to environmental endocrine disruptors during pregnancy is associated with pediatric germ cell tumors

This study aimed to evaluate the efficacy of interventions to reduce patient misidentification incidents classified as level 2 and over (adverse events occurred for patients) with the step-by-step problem-solving method. All incidents related to patient misidentification were selected, and relevant information was collected from the original electronic incident reports. We then conducted an eight-step problem-solving process with the aim of reducing patient misclassification and improving patient safety. Step 1: the number of misidentification-related incident reports and the percentage of these reports in the total incident reports increased each year. Step 2: the most frequent misidentification type was sample collection tubes, followed by drug administration and hospital meals. Step 3: we set a target of an 20% decrease in patient misidentification cases classified as level 2 or over compared with the previous year, and established this as a hospital priority. Step 4: we found that discrepancies in patient identification procedures were the most important causes of misidentification. Step 5: we standardized the patient identification process to achieve an 10% reduction in misidentification. Step 6: we disseminated instructional videos to all staff members. Step 7: we confirmed there was an 18% reduction in level 2 and over patient misidentification compared with the previous year. Step 8: we intend to make additional effort to decrease misidentification of patients by a further 10%. Level 2 and over patient misidentification can be reduced by a patient identification policy using a step-by-step problem-solving procedure. This study aimed to evaluate the efficacy of interventions to reduce patient misidentification incidents with step-by-step problem-solving method. Continued seamless efforts to eliminate patient misidentification are mandatory for this activity.

Toenail mercury levels positively correlate with obesity and abdominal obesity among Korean adults

BACKGROUND

Although previous studies have shown that short-term exposure to mercury is associated with obesity, it should be noted that mercury is not easily released and that it constantly accumulates in the body. However, few studies have explored the association between chronic mercury exposure and obesity. This study aimed to examine the association between chronic mercury exposure and obesity in Korean adults.

METHODS

The study used baseline data from the Trace Element Study of Korean Adults in Yeungnam area. A total of 495 participants aged 40-69 years who provided the required information (demographic, diet, lifestyle, toenail mercury levels, and health examination results) were included. Toenail mercury levels were measured using neutron-activation analysis. Body mass index and waist circumference were obtained from medical examination. Multivariable-adjusted logistic regression and restricted cubic spline regression were used in the analysis.

RESULTS

In the fully adjusted logistic regression models, participants with the highest toenail mercury levels had a higher prevalence of obesity (odds ratio [OR]: 3.26, 95 % confidence interval [CI]: 1.79-5.93) and abdominal obesity (OR: 2.30, 95 % CI: 1.15-4.59). In the cubic spline regression model, linear relationships were confirmed between increased toenail mercury levels and higher prevalence of obesity and abdominal obesity (all p > 0.05 for nonlinearity).

CONCLUSIONS

In summary, chronic mercury exposure was associated with higher prevalence of obesity and abdominal obesity in Korean adults. Therefore, the development of public health interventions against environmental exposure of foods is required to manage and prevent obesity.

Endocrine Disruptors and the Induction of Insulin Resistance

INTRODUCTION

The incidence of insulin resistance syndrome and type 2 diabetes mellitus has increased at an alarming rate worldwide and constitutes a serious challenge to public health care in the 21st century. Endocrine disrupting chemicals are defined as "substances or mixtures of substances that alter the endocrine system functions and, hence, adversely affect organisms, their progeny, or sub populations" and may be associated with this increase in prevalence.

OBJECTIVE

This study aimed to assess the role of endocrine disrupting chemicals in insulin resistance and the importance of approaching the subject during anamnesis.

METHODS

A full review of the literature regarding insulin resistance, type-2 diabetes and endocrine disruptors were conducted.

CONCLUSION

Large-scale production and distribution of endocrine disrupting chemicals coincide with the increase in the prevalence of insulin resistance globally. In recent years, studies have shown that endocrine disrupting chemicals are positively associated with insulin resistance syndrome, evidenced by worse prognoses among individuals with higher levels of exposure. Health professionals should recognize the forms of exposure, most susceptible people, and lifestyle habits that can worsen patients' prognoses.

The Redox Communication Network as a Regulator of Metabolism

Key tissues are dysfunctional in obesity, diabetes, cardiovascular disease, fatty liver and other metabolic diseases. Focus has centered on individual organs as though each was isolated. Attention has been paid to insulin resistance as the key relevant pathosis, particularly insulin receptor signaling. However, many tissues play important roles in synergistically regulating metabolic homeostasis and should be considered part of a network. Our approach identifies redox as an acute regulator of the greater metabolic network. Redox reactions involve the transfer of electrons between two molecules and in this work refer to commonly shared molecules, reflective of energy state, that can readily lose electrons to increase or gain electrons to decrease the oxidation state of molecules including NAD(P), NAD(P)H, and thiols. Metabolism alters such redox molecules to impact metabolic function in many tissues, thus, responding to anabolic and catabolic stimuli appropriately and synergistically. It is also important to consider environmental factors that have arisen or increased in recent decades as putative modifiers of redox and reactive oxygen species (ROS) and thus metabolic state. ROS are highly reactive, controlled by the thiol redox state and influence the function of thousands of proteins. Lactate (L) and pyruvate (P) in cells are present in a ratio of about 10 reflective of the cytosolic NADH to NAD ratio. Equilibrium is maintained in cells because lactate dehydrogenase is highly expressed and near equilibrium. The major source of circulating lactate and pyruvate is muscle, although other tissues also contribute. Acetoacetate (A) is produced primarily by liver mitochondria where β-hydroxybutyrate dehydrogenase is highly expressed, and maintains a ratio of β-hydroxybutyrate (β) to A of about 2, reflective of the mitochondrial NADH to NAD ratio. All four metabolites as well as the thiols, cysteine and glutathione, are transported into and out of cells, due to high expression of relevant transporters. Our model supports regulation of all collaborating metabolic organs through changes in circulating redox metabolites, regardless of whether change was initiated exogenously or by a single organ. Validation of these predictions suggests novel ways to understand function by monitoring and impacting redox state.

Maternal exposure to environmental endocrine disruptors during pregnancy is associated with pediatric germ cell tumors

Environmental endocrine disruptors (EEDs) are natural or synthetic chemical compounds that interfere with normal endocrine function in both wildlife and humans. Previous studies have indicated that EEDs may contribute to oncogenesis. This study explores the relationship between EEDs and pediatric germ cell tumors (GCTs). A case-control study was conducted in 84 pediatric patients from 2014 to 2017, including 42 subjects with immature teratoma, yolk sac tumor, or germinoma, and 42 controls who experienced pneumonia or trauma. Serum PFASs, including PFBS, PFHpA, PFHxS, PFOA, PFOS, PFNA, PFDA, PFUA, PFOSA, and PFDoA, were measured in each subject, and their history of possible EED exposure was reviewed. Six of the 10 measured PFASs were significantly increased in the GCT group relative to the control group. With respect to lifestyle history, only PFHxS levels were statistically significantly associated with GCTs as determined by logistic regression analysis. The odds ratio for a 1 ng/L increase in PFHxS was 19.47 (95% CI: 4.20-90.26). Furthermore, in the GCT and control groups, both parental consumption of barbecued foods and hair dye use among parents were significantly correlated with elevated serum PFHxS levels (ρ = 0.383, 0.325 in the patient group and ρ = 0.370, 0.339 in the control group; p < 0.05). Our study confirmed that children with GCTs from our institute had relatively high serum levels of PFASs relative to those of tumor-free pediatric patients. Serum PFHxS levels were independently associated with germ cell tumor occurrence.

Bisphenol A and the Risk of Obesity a Systematic Review With Meta-Analysis of the Epidemiological Evidence

Bisphenol A (BPA) is suspected to be associated with several chronic metabolic diseases. The aim of the present study was to review previous epidemiological studies that examined the relationship between BPA exposure and the risk of obesity. PubMed, Web of Science, and Embase databases were systematically searched by 2 independent investigators for articles published from the start of database coverage until January 1, 2020. Subsequently, the reference list of each relevant article was scanned for any other potentially eligible publications. We included observational studies published in English that measured urinary BPA. Odds ratios with corresponding 95% confidence intervals for the highest versus lowest level of BPA were calculated. Ten studies with a sample size from 888 to 4793 participants met our inclusion criteria. We found a positive correlation between the level of BPA and obesity risk. A dose-response analysis revealed that 1-ng/mL increase in BPA increased the risk of obesity by 11%. The similar results were for different type of obesity, gender, and age.

Identification of metabolic pathways related to the bisphenol A-induced adipogenesis in differentiated murine adipocytes by using RNA-sequencing

We evaluated the effect of bisphenol A and its metabolites on the 3T3-L1 cells, in terms of glucose and lipid metabolism. We also aimed to obtain the information on the genome-wide expression changes in the 3T3-L1 cells treated with Bisphenol A by using RNA-seq, which involves whole-transcriptome sequencing. Differentially Expressed Genes (DEGs) collected from RNA-seq can be used to produce a complete picture of related metabolism pathways. The KEGG pathway was extracted based on the DEGs. Bisphenol A significantly increased the mRNA level of Sterol regulatory element binding transcription factor 1 (Srebf1) and CCAAT/enhancer binding protein alpha (Cebpa). Lipoprotein lipase (Lpl) was also significantly influenced by bisphenol A and its metabolites. Acetyl-Coenzyme A carboxylase beta (Acacb) and Fatty acid synthase (Fasn) mRNA levels were elevated by bisphenol A and its metabolites. The insulin signaling pathway, neurotrophin signaling pathway, and endometrial cancer-related pathway were focused by the functional enrichment analyses, and the pathways were well coincided with recent previous reports. DEGs collected from RNA-seq were confirmed as a reliable evidence in the exposure to the chemicals such as bisphenol A. Collecting pieces of the puzzles obtained from the RNA-seq will help us to produce a complete picture of the metabolic pathway for such chemicals.

Urinary phthalate metabolites and metabolic syndrome in U.S. adolescents: Cross-sectional results from the National Health and Nutrition Examination Survey (2003-2014) data

OBJECTIVE

There is limited research on the association between phthalates and metabolic syndrome (MetS). Among adolescents, phthalate exposure, which can occur from multiple sources, has been linked to several risk factors for MetS. The objective was to investigate the association between urinary phthalate metabolite concentrations (i.e., mono-ethyl phthalate (MEP), mono-n-butyl phthalate (MnBP), mono-isobutyl phthalate (MiBP), mono-benzyl phthalate (MBzP), mono-(3-carboxylpropyl) phthalate (MCPP), and di(2-ethylhexyl phthalate (DEHP)) and MetS in adolescents aged 12-19 years using the National Health and Nutrition Examination Survey (NHANES) data (2003-2014). A secondary aim was to assess if observed associations varied by a measure of socioeconomic status, economic adversity, which was defined using parental income and educational attainment as well as household food security.

METHODS

We used NHANES data which included physical examination, laboratory urinalysis and fasting blood profiles, and self-reported health characteristics and demographics. Physical examination and laboratory data were used to obtain values of MetS components and urinary phthalate metabolites. We created age-, sex-, and survey year-specific tertiles of creatinine-corrected urinary phthalate metabolites. Analysis was performed using appropriate weighting procedures that accounted for NHANES' complex sampling design. After univariate and bivariate analyses, we performed adjusted logistic regressions to test for associations between individual phthalate metabolites and MetS as well as MetS components and number of MetS components, separately, using the lowest tertile as the reference category. A cross-product term (phthalate metabolite*economic adversity) was subsequently added to adjusted models.

RESULTS

Among 918 participants (mean age 16 years, 45% female, 18% with economic adversity), the prevalence of MetS was 5.3%. Prior to adjustment, adolescents with MetS had marginally higher concentrations of phthalate metabolites than adolescents without MetS. There was a suggestive positive association between intermediate concentrations of MnBP and odds of MetS after adjustment (T2: Odds Ratio (OR) = 2.66 (95% confidence interval: 0.98-7.24); T3: OR = 2.11 (0.71-6.27)). Males with higher MnBP concentrations had higher odds of dyslipidemia; however, associations were mostly non-significant for females. Relationships between MiBP concentrations and odds of MetS varied by sex. Males with higher concentrations of MnBP and MiBP had greater odds of having a higher number of MetS components. Relationships between phthalate metabolites and MetS did not vary by economic adversity.

CONCLUSION

There was a suggestive positive association between MnBP and MetS among adolescents. Associations between phthalate metabolites and MetS as well as MetS components may vary by sex, but may not vary by economic adversity. Further research of the relationships between phthalate exposures, MetS, and potential interactions with socioeconomic factors is warranted.

Air pollution, environmental chemicals, and smoking may trigger vitamin D deficiency: Evidence and potential mechanisms

Beyond vitamin D (VD) effect on bone homeostasis, numerous physiological functions in human health have been described for this versatile prohormone. In 2016, 95% of the world's population lived in areas where annual mean ambient particulate matter (<2.5 μm) levels exceeded the World Health Organization guideline value (Shaddick et al., 2018). On the other hand, industries disperse thousands of chemicals continually into the environment. Further, considerable fraction of populations are exposed to tobacco smoke. All of these may disrupt biochemical pathways and cause detrimental consequences, such as VD deficiency (VDD). In spite of the remarkable number of studies conducted on the role of some of the above mentioned exposures on VDD, the literature suffers from two main shortcomings: (1) an overview of the impacts of environmental exposures on the levels of main VD metabolites, and (2) credible engaged mechanisms in VDD because of those exposures. To summarize explanations for these unclear topics, we conducted the present review, using relevant keywords in the PubMed database, to investigate the adverse effects of exposure to air pollution, some environmental chemicals, and smoking on the VD metabolism, and incorporate relevant potential pathways disrupting VD endocrine system (VDES) leading to VDD. Air pollution may lead to the reduction of VD cutaneous production either directly by blocking ultraviolet B photons or indirectly by decreasing outdoor activity. Heavy metals may reduce VD serum levels by increasing renal tubular dysfunction, as well as downregulating the transcription of cytochrome P450 mixed-function oxidases (CYPs). Endocrine-disrupting chemicals (EDCs) may inhibit the activity and expression of CYPs, and indirectly cause VDD through weight gain and dysregulation of thyroid hormone, parathyroid hormone, and calcium homeostasis. Smoking through several pathways decreases serum 25(OH)D and 1,25(OH)2D levels, VD intake from diet, and the cutaneous production of VD through skin aging. In summary, disturbance in the cutaneous production of cholecalciferol, decreased intestinal intake of VD, the modulation of genes involved in VD homeostasis, and decreased local production of calcitriol in target tissues are the most likely mechanisms that involve in decreasing the serum VD levels.

History of the Obesogen Field: Looking Back to Look Forward

The Obesogen field developed from two separate scientific research areas, endocrine disruptors and the Developmental Origins of Health and Disease (DOHaD). Endocrine Disrupting Chemicals (EDCs) are exogenous chemicals or mixtures of chemicals that interfere with the action of hormones. Exposure to EDCs during early development (DOHaD) has been shown to increase susceptibility to a variety of diseases including infertility, asthma, breast and prostate cancer, early puberty, susceptibility to infections, heart disease, autoimmune disease, and attention deficit hyperactivity disorder/learning disability. The effects of EDCs on obesity and fat cell development first gained attention around the turn of the twenty-first century. In 2002 Dr. Paula Baillie-Hamilton wrote the first review article focusing on environmental chemicals and obesity. She suggested that the obesity epidemic correlated with the increased production of chemicals after World War II. Baillie-Hamilton identified studies showing that exposures to a variety of chemicals led to weight gain. Shortly after that a commentary on an article showing that nonylphenol would increase fat cell differentiation in vitro noted the Baillie-Hamilton article and made the point that perhaps obesity was due in part to exposure to EDCs. In 2006 the field of DOHaD/EDCs and obesity made a giant leap forward when Dr. Bruce Blumberg published a paper showing that tributyltin could lead to weight gain in mice and coined the term obesogen for a chemical that caused weight gain and lead to obesity. In 2011, the NIEHS developed the first funding initiative focused on obesogens. In the following years there have been several workshops focused on obesogens. This paper describes these early days that lead to the obesogen hypotheses and the growth of the field for a decade, leading to its prominence today, and provides some insight into where the field is moving.

Triiodothyronine and leptin repletion in humans similarly reverse weight-loss-induced changes in skeletal muscle

Subjects maintaining a ≥10% dietary weight loss exhibit decreased circulating concentrations of bioactive thyroid hormones and increased skeletal muscle work efficiency largely due to increased expression of more-efficient myosin heavy chain (MHC) isoforms (MHC I) and significantly mediated by the adipocyte-derived hormone leptin. The primary purpose of this study was to examine the effects of triiodothyronine (T₃) repletion on energy homeostasis and skeletal muscle physiology in weight-reduced subjects and to compare these results with the effects of leptin repletion. Nine healthy in-patients with obesity were studied at usual weight (Wt_initial) and following a 10% dietary weight loss while receiving 5 wk of a placebo (Wt_-10%placebo) or T₃ (Wt_-10%T3) in a single-blind crossover design. Primary outcome variables were skeletal muscle work efficiency and vastus lateralis muscle mRNA expression. These results were compared with the effects of leptin repletion in a population of 22 subjects, some of whom participated in a previous study. At Wt_-10%placebo, skeletal muscle work efficiency and relative expression of the more-efficient/less-efficient MHC I/MHC II isoforms were significantly increased and the ratio of the less-efficient to the more-efficient sarco(endo)plasmic reticulum Ca²⁺-ATPase isoforms (SERCA1/SERCA2) was significantly decreased. These changes were largely reversed by T₃ repletion to a degree similar to the changes that occurred with leptin repletion. These data support the hypothesis that the effects of leptin on energy expenditure in weight-reduced individuals are largely mediated by T₃ and suggest that further study of the possible role of thyroid hormone repletion as adjunctive therapy to help sustain weight loss is needed.

Reproductive and developmental F1 toxicity following exposure of pubescent F0 male mice to bisphenol A alone and in a combination with X-rays irradiation

Exposure to environmental toxicants may affect reproduction and development of subsequent generations. This study was aimed at determining the male-mediated F1 effects induced following 8-weeks of subchronic exposure of F0 male mice to bisphenol A (BPA) alone and in a combination with X-rays irradiation (IR) started during their puberty. 4.5 weeks old F0 male mice were exposed to BPA dissolved in ethyl alcohol and diluted in drinking water at the following doses: 5 mg/kg bw, 10 mg/kg bw, 20 mg/kg bw or irradiated with X-rays (0.05 Gy) or exposed to a combination of low doses of both agents (0.05 Gy + 5 mg/kg bw BPA). Immediately after the end of the 8 weeks exposure F0 males were caged with two unexposed females each. Three quarters of the mated females from each group were sacrificed 1 day before expected parturition for examination of prenatal development of the offspring. The remainder of the females from each group were allowed to deliver and rear litters. Pups of exposed males were monitored for postnatal development for 8 weeks. At 8-9 weeks of age 6-8 males from each group of F1 generation were sacrificed to determine sperm count and quality. The current results, compared to the earlier results, showed that exposure of pubescent males to BPA alone or in combination with irradiation may be more damaging to their offspring than the exposure of adult males. The exposure of pubescent males to BPA alone and in combination with irradiation significantly increased the frequency of abnormal skeletons of surviving fetuses, increased the percent of mortality of pups in the F1 generation, reduced the sperm motility of F1 males and may induce obesity. Additionally, the combined BPA and irradiation exposure reduced the number of total and live implantations, whereas the exposure to BPA alone disturbed the male:female sex ratio. The above results may be caused by genetic or by epigenetic mechanisms. Limitation of use of products including BPA, especially by children and teenagers, is strongly recommended.

The role of genetic variation of human metabolism for BMI, mental traits and mental disorders

OBJECTIVE

The aim was to assess whether loci associated with metabolic traits also have a significant role in BMI and mental traits/disorders METHODS: We first assessed the number of single nucleotide polymorphisms (SNPs) with genome-wide significance for human metabolism (NHGRI-EBI Catalog). These 516 SNPs (216 independent loci) were looked-up in genome-wide association studies for association with body mass index (BMI) and the mental traits/disorders educational attainment, neuroticism, schizophrenia, well-being, anxiety, depressive symptoms, major depressive disorder, autism-spectrum disorder, attention-deficit/hyperactivity disorder, Alzheimer's disease, bipolar disorder, aggressive behavior, and internalizing problems. A strict significance threshold of p < 6.92 × 10-6 was based on the correction for 516 SNPs and all 14 phenotypes, a second less conservative threshold (p < 9.69 × 10-5) on the correction for the 516 SNPs only.

RESULTS

19 SNPs located in nine independent loci revealed p-values < 6.92 × 10-6; the less strict criterion was met by 41 SNPs in 24 independent loci. BMI and schizophrenia showed the most pronounced genetic overlap with human metabolism with three loci each meeting the strict significance threshold. Overall, genetic variation associated with estimated glomerular filtration rate showed up frequently; single metabolite SNPs were associated with more than one phenotype. Replications in independent samples were obtained for BMI and educational attainment.

CONCLUSIONS

Approximately 5-10% of the regions involved in the regulation of blood/urine metabolite levels seem to also play a role in BMI and mental traits/disorders and related phenotypes. If validated in metabolomic studies of the respective phenotypes, the associated blood/urine metabolites may enable novel preventive and therapeutic strategies.

Frontiers in endocrine disruption: Impacts of organotin on the hypothalamus-pituitary-thyroid axis

Endocrine disruptors (EDs), chemical substances widely used in industry and ubiquitously distributed in the environment, are able to interfere with the synthesis, release, transport, metabolism, receptor binding, action, or elimination of endogenous hormones. EDs affect homeostasis mainly by acting on nuclear and nonnuclear steroid receptors but also on serotonin, dopamine, norepinephrine and orphan receptors in addition to thyroid hormone receptors. Tributyltin (TBT), an ED widely used as a pesticide and biocide in antifouling paints, has well-documented actions that include inhibiting aromatase and affecting the nuclear receptors PPARγ and RXR. TBT exposure in humans and experimental models has been shown to mainly affect reproductive function and adipocyte differentiation. Since thyroid hormones play a fundamental role in regulating the basal metabolic rate and energy homeostasis, it is crucial to clarify the effects of TBT on the hypothalamus-pituitary-thyroid axis. Therefore, we review herein the main effects of TBT on important metabolic pathways, with emphasis on disruption of the thyroid axis that could contribute to the development of endocrine and metabolic disorders, such as insulin resistance and obesity.

Adipose Tissue as a Site of Toxin Accumulation

We examine the role of adipose tissue, typically considered an energy storage site, as a potential site of toxicant accumulation. Although the production of most persistent organic pollutants (POPs) was banned years ago, these toxicants persist in the environment due to their resistance to biodegradation and widespread distribution in various environmental forms (e.g., vapor, sediment, and water). As a result, human exposure to these toxicants is inevitable. Largely due to their lipophilicity, POPs bioaccumulate in adipose tissue, resulting in greater body burdens of these environmental toxicants with obesity. POPs of major concern include polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs), and polybrominated biphenyls and diphenyl ethers (PBBs/PBDEs), among other organic compounds. In this review, we (i) highlight the physical characteristics of toxicants that enable them to partition into and remain stored in adipose tissue, (ii) discuss the specific mechanisms of action by which these toxicants act to influence adipocyte function, and (iii) review associations between POP exposures and the development of obesity and diabetes. An area of controversy relates to the relative potential beneficial versus hazardous health effects of toxicant sequestration in adipose tissue. © 2017 American Physiological Society. Compr Physiol 7:1085-1135, 2017.

Sex Hormones, Gonadotropins, and Sex Hormone-binding Globulin in Infants Fed Breast Milk, Cow Milk Formula, or Soy Formula

Measurement of endogenous hormones in early life is important to investigate the effects of hormonally active environmental compounds. To assess the possible hormonal effects of different feeding regimens in different sample matrices of infants, 166 infants were enrolled from two U.S hospitals between 2006 and 2009. The children were classified into exclusive soy formula, cow milk formula or breast milk regimens. Urine, saliva and blood samples were collected over the first 12 months of life. Estradiol, estrone, testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and sex hormone-binding globulin (SHBG) levels were measured in the three matrices. Lower estradiol and LH levels were found in urine and saliva samples of soy formula-fed boys compared to cow formula-fed boys. Higher LH level was found in urine samples of soy formula-fed girls compared to cow formula-fed girls. However, we found neither a neonatal testosterone rise in the boys nor a gender-specific difference in testosterone levels, which suggests that urinary testosterone levels may not accurately reflect blood levels during mini-puberty. Nevertheless, our study shows that blood, urine and saliva samples are readily collectible and suitable for multi-hormone analyses in children and allow examination of hypotheses concerning endocrine effects from dietary compounds.

Instant noodle consumption is associated with cardiometabolic risk factors among college students in Seoul

BACKGROUND/OBJECTIVES

Increased consumption of instant noodles has recently been reported to be positively associated with obesity and cardiometabolic syndrome in South Korea, which has the highest per capita instant noodle consumption worldwide. This study aimed to investigate the association between instant noodle consumption and cardiometabolic risk factors among college students in Seoul.

SUBJECTS/METHODS

The study subjects consisted of 3,397 college students (1,782 male; 1,615 female) aged 18-29 years who participated in a health checkup. Information on instant noodle consumption was obtained from the participants' answers to a question about their average frequency of instant noodle intake over the 1 year period prior to the survey.

RESULTS

Statistical analysis using a general linear model that adjusted for age, body mass index, gender, family income, health-related behaviors, and other dietary factors important for cardiometabolic risk, showed a positive association between the frequency of instant noodle consumption and plasma triglyceride levels, diastolic blood pressure, and fasting blood glucose levels in all subjects. Compared to the group with the lowest frequency of instant noodle intake (≤ 1/month), the odds ratio for hypertriglyceridemia in the group with an intake of ≥ 3/week was 2.639 [95% confidence interval (CI), 1.393–5.000] for all subjects, while it was 2.149 (95% CI, 1.045–4.419) and 5.992 (95% CI, 1.859–21.824) for male and female students, respectively. In female students, diastolic blood pressure was also higher among more frequent consumers of instant noodles.

CONCLUSIONS

Our results suggest that frequent consumption of instant noodles may be associated with increased cardiometabolic risk factors among apparently healthy college students aged 18–29 years.

Epigallocatechin-3-gallate inhibits adipogenesis through down-regulation of PPARγ and FAS expression mediated by PI3K-AKT signaling in 3T3-L1 cells

Epigallocatechin-3-gallate (EGCG), a major component in green tea, functions as extensive bioactivities including anti-inflammation, anti-oxidation, and anti-cancer. However, little is known about its anti-adipogenesis and underlying mechanisms. The purport of this study sought to investigate effects of EGCG on 3T3-L1 preadipocyte differentiation and to explore its possible mechanisms. The 3T3-L1 cells were induced to differentiate under the condition of pro-adipogenic cocktail with or without indicated EGCG concentrations (10, 50, 100, 200µM) for 2, 4, 6 and 8 days, respectively. Also, another batch of 3T3-L1 cells was induced under the optimal EGCG concentration (100µM) with or without SC3036 (PI3K activator, 10µM) or SC79 (AKT activator, 0.5µM) for 8 days. Subsequently, the cell viability was examined by MTT assay and the cell morphology was visualized by Oil red O staining. Finally, the mRNA levels including peroxisome proliferator activated receptor γ (PPARγ) and fatty acid synthase (FAS) were detected by quantitative real time PCR, while the protein levels of PPARγ, FAS, phosphatidylinositol 3 kinase (PI3K), insulin receptor substrate1(IRS1), AKT, and p-AKT were measured by immunoblotting analysis. Our results showed that EGCG inhibited adipogenesis of 3T3-L1 preadipocyte in a concentration-dependent manner. Moreover, the inhibitory effects were reversed by SC3036 or SC79, suggesting that the inhibitory effects of EGCG are mediated by PI3K-AKT signaling to down-regulate PPARγ and FAS expression levels. The findings shed light on EGCG anti-adipogenic effects and its underlying mechanism and provide a novel preventive-therapeutic potential for obesity subjects as a compound from Chinese green tea.

Do environmental pollutants increase obesity risk in humans?

OBJECTIVES

Obesity has become a global epidemic and threat to public health. A good understanding of the causes can help attenuate the risk and spread. Environmental pollutants may have contributed to the rising global obesity rates. Some research reported associations between chemical pollutants and obesity, but findings are mixed. This study systematically examined associations between chemical pollutants and obesity in human subjects.

METHODS

Systematic review of relevant studies published between 1 January 1995 and 1 June 2016 by searching PubMed and MEDLINE®.

RESULTS

Thirty-five cross-sectional (n = 17) and cohort studies (n = 18) were identified that reported on associations between pollutants and obesity measures. Of them, 16 studies (45.71%) reported a positive association; none reported a sole inverse association; three (8.57%) reported a null association only; six (17.14%) reported both a positive and null association; seven (20.00%) reported a positive and inverse association; and three studies (8.57%) reported all associations (positive, inverse and null). Most studies examined the association between multiple different pollutants, different levels of concentration and in subsamples, which results in mixed results. Thirty-three studies reported at least one positive association between obesity and chemicals, such as polychlorinated biphenyls, biphenyl A, dichlorodiphenyltrichloroethane, dichlorodiphenyldichloroethylene and more. Certain chemicals, such as biphenyl A, were more likely to have high ORs ranging from 1.0 to 3.0, whereas highly chlorinated polychlorinated biphenyls were more likely to have negative ORs. Effects of chemicals on the endocrine system and obesity might vary by substance, exposure level, measure of adiposity and subject characteristics (e.g. sex and age).

CONCLUSIONS

Accumulated evidences show positive associations between pollutants and obesity in humans. Future large, long-term, follow-up studies are needed to assess impact of chemical pollutants on obesity risk and related mechanisms.

An Informatics Approach to Evaluating Combined Chemical Exposures from Consumer Products: A Case Study of Asthma-Associated Chemicals and Potential Endocrine Disruptors

BACKGROUND

Simultaneous or sequential exposure to multiple environmental stressors can affect chemical toxicity. Cumulative risk assessments consider multiple stressors but it is impractical to test every chemical combination to which people are exposed. New methods are needed to prioritize chemical combinations based on their prevalence and possible health impacts.

OBJECTIVES

We introduce an informatics approach that uses publicly available data to identify chemicals that co-occur in consumer products, which account for a significant proportion of overall chemical load.

METHODS

Fifty-five asthma-associated and endocrine disrupting chemicals (target chemicals) were selected. A database of 38,975 distinct consumer products and 32,231 distinct ingredient names was created from online sources, and PubChem and the Unified Medical Language System were used to resolve synonymous ingredient names. Synonymous ingredient names are different names for the same chemical (e.g., vitamin E and tocopherol).

RESULTS

Nearly one-third of the products (11,688 products, 30%) contained ≥ 1 target chemical and 5,229 products (13%) contained > 1. Of the 55 target chemicals, 31 (56%) appear in ≥ 1 product and 19 (35%) appear under more than one name. The most frequent three-way chemical combination (2-phenoxyethanol, methyl paraben, and ethyl paraben) appears in 1,059 products. Further work is needed to assess combined chemical exposures related to the use of multiple products.

CONCLUSIONS

The informatics approach increased the number of products considered in a traditional analysis by two orders of magnitude, but missing/incomplete product labels can limit the effectiveness of this approach. Such an approach must resolve synonymy to ensure that chemicals of interest are not missed. Commonly occurring chemical combinations can be used to prioritize cumulative toxicology risk assessments.

CITATION

Gabb HA, Blake C. 2016. An informatics approach to evaluating combined chemical exposures from consumer products: a case study of asthma-associated chemicals and potential endocrine disruptors. Environ Health Perspect 124:1155-1165; http://dx.doi.org/10.1289/ehp.1510529.

An Emerging Role of micro-RNA in the Effect of the Endocrine Disruptors

Endocrine-disrupting chemicals (EDCs) are diverse natural and synthetic chemicals that may alter various mechanisms of the endocrine system and produce adverse developmental, reproductive, metabolic, and neurological effects in both humans and wildlife. Research on EDCs has revealed that they use a variety of both nuclear receptor-mediated and non-receptor-mediated mechanisms to modulate different components of the endocrine system. The molecular mechanisms underlying the effects of EDCs are still under investigation. Interestingly, some of the effects of EDCs have been observed to pass on to subsequent unexposed generations, which can be explained by the gametic transmission of deregulated epigenetic marks. Epigenetics is the study of heritable changes in gene expression that occur without a change in the DNA sequence. Epigenetic mechanisms, including histone modifications, DNA methylation, and specific micro-RNAs (miRNAs) expression, have been proposed to mediate transgenerational transmission and can be triggered by environmental factors. MiRNAs are short non-coding RNA molecules that post-transcriptionally repress the expression of genes by binding to 3′-untranslated regions of the target mRNAs. Given that there is mounting evidence that miRNAs are regulated by hormones, then clearly it is important to investigate the potential for environmental EDCs to deregulate miRNA expression and action.

Peroxisome proliferator-activated receptors and biotransformation responses in relation to condition factor and contaminant burden in tilapia species from Ogun River, Nigeria

A major development in fishery science has been the Fulton's condition factor (CF) as a reliable physiological index of fish growth and health status (Fulton 1902). As a general rule, CF-value greater than 1 (>1) should be regarded as an indicator for good growth and health. Therefore, exposure of fish to contaminants in the environment will be expected to produce a reduction in scope for growth, since energy for growth will be allocated to overcome stressful conditions. In the present study, we hypothesized that tilapia species from Ogun River (Nigeria) are experiencing severe contaminant-induced obesogen effects leading to high CF (≥ 2) in fish with pathological alterations. The environmental obesogen hypothesis has related the interaction between environmental pollutants and PPAR isoform activation In this respect, peroxisome proliferator-activated receptors (PPARs) and biotransformation responses in relation to contaminant burden were investigated in a total of 1074 specimens of Tilapias species (Tilapia guineensis, Sarotherodon galileaus and Oreochromis niloticus) collected from three areas with different degrees of anthropogenic contamination and from a putative control site along the Ogun River. Liver mRNA expression of cytochrome cyp1 isoforms (cyp1a, 1b and 1c) and PPAR isoforms (ppar-α, β and γ) were analyzed using validated real-time PCR. Fish were also analyzed for CF and muscle contaminant burden (aliphatic and polycyclic aromatic hydrocarbons, organochlorine pesticides, and polychlorinated biphenyls). A significant increase in mRNA expression of cyp1- and ppar isoforms was observed in fish from polluted areas, and these results paralleled data on PCBs and PAHs tissue concentrations. Further, cyp1 isoforms showed clear sex-related differences, with higher mRNA expression in male fish than in females. Principal component analysis revealed a relationship between cyp1 isoforms, ppar-α, β, PCBs and PAHs and these interactions may suggest a crosstalk between AhR- and PPARs mediated pathways on metabolic and energetic processes. The PCA biplot also highlighted a positive relationship between ppar-γ, body weight, total length and PAHs. The CF for fish from all the sites was ≥ 2 indicating that this parameter may not be a reliable index for evaluating fish growth and health condition, especially in wild fish population exposed to complex cocktails of environmental pollutants.

Bisphenol-A and Sleep Adequacy among Adults in the National Health and Nutrition Examination Surveys

STUDY OBJECTIVES

To evaluate bisphenol-A (BPA) level and its relationship to sleep adequacy in a nationally representative sample of U.S. adults.

METHODS

A population-based cross-sectional study was conducted using 2005-2010 National Health and Nutrition Examination Survey whereby data were collected using in-person interviews, physical examination and laboratory testing. BPA level was measured in urine samples and analyzed as loge-transformed variable and in quartiles (< 0.9 ng/mL; 0.9 to < 1.9 ng/mL; 1.9 to < 3.7 ng/mL; 3.7+ ng/mL). Sleep adequacy was operationalized with three questions: "How much sleep do you usually get at night on weekdays or workdays?", "Have you ever told a doctor or other health professionals that you have trouble sleeping?" and "Have you ever been told by a doctor or other health professional that you have a sleep disorder?" Sleep duration was further categorized as (< 6 h, ≥ 6 h); (< 7 h, 7-8 h, > 8 h); (< 5 h, 5-6 h, 7-8 h, ≥ 9 h). Linear, binary, and ordinal logistic regression models were constructed.

RESULTS

Loge-transformed BPA level was inversely related to sleep duration defined, in hours, as a continuous variable, a dichotomous variable (≥ 6, < 6), or an ordinal variable (≥ 9, 7-8, 5-6, < 5), after adjustment for confounders. Help-seeking behavior for sleep problems and diagnosis with sleep disorders were not significantly associated with loge-transformed BPA level in fully adjusted models.

CONCLUSIONS

Loge-transformed BPA level may be associated with fewer hours of sleep among U.S. adults, with implications for prevention. Further research involving diverse populations are needed to confirm these study findings.

Alteration of cellular lipids and lipid metabolism markers in RTL-W1 cells exposed to model endocrine disrupters

This work investigates the suitability of the rainbow trout liver cell line (RTL-W1) as an in-vitro model to study the ability of model endocrine disrupters, namely TBT, TPT, 4-NP, BPA and DEHP, to act as metabolic disrupters by altering cellular lipids and markers of lipid metabolism. Among the tested compounds, BPA and DEHP significantly increased the intracellular accumulation of triacylglycerols (TAGs), while all the compounds -apart from TPT-, altered membrane lipids - phosphatidylcholines (PCs) and plasmalogen PCs - indicating a strong interaction of the toxicants with cell membranes and cell signaling. RTL-W1 expressed a number of genes involved in lipid metabolism that were modulated by exposure to BPA, TBT and TPT (up-regulation of FATP1 and FAS) and 4-NP and DEHP (down-regulation of FAS and LPL). Multiple and complex modes of action of these chemicals were observed in RTL-W1 cells, both in terms of expression of genes related to lipid metabolism and alteration of cellular lipids. Although further characterization is needed, this might be a useful model for the detection of chemicals leading to steatosis or other diseases associated with lipid metabolism in fish.