Diethylhexyl Phthalate Research Articles

Flat membrane-based electromembrane extraction coupled with UV–visible spectrophotometry for the determination of diethylhexyl phthalate in water samples

A polyacrylonitrile (PAN)/polydimethylsiloxane (PDMS) membrane supported with an appropriate quantity of titanium dioxide (TiO2) nanoparticles was electrospun. The membrane was used in a two-phase electromembrane extraction (EME) setup for extracting diethylhexyl phthalate (DEHP) from aqueous samples. Some effective parameters on the extraction efficiency including applied voltage, agitation rate, and extraction time were optimized by the central composite design (CCD) method; the others including the donor pH, acceptor volume and type were optimized using the ‘one variable at a time’ method. The target analyte, DEHP, was detected by ultraviolet–visible (UV–Vis) spectrophotometry. The coefficient of determination (R2), relative standard deviation (RSD), limit of detection (LOD) and limit of quantification (LOQ) in the concentration range of 20–1000 ng mL−1 were 0.9944, <8%, 5 ng mL−1 and 16.67 ng mL−1, respectively. The relative recoveries (RRs) of DEHP in some real samples including saline serum and boiled water by electric plastic kettle were over 97%. The extraction of DEHP from 10 mL of water totally consumed 0.33 Wh of electric energy.

Peroxiredoxin 5 prevents diethylhexyl phthalate-induced neuronal cell death by inhibiting mitochondrial fission in mouse hippocampal HT-22 cells

Diethylhexyl phthalate (DEHP) is used in many plastic products, such as perfumes, lunch boxes, bags, and building materials. As DEHP is not covalently bound to the plastic, humans can be easily exposed to it. DEHP induces neurobehavioral changes and neuronal cell death; however, the exact mechanism behind this is still unclear. We hypothesized that the neurotoxic mechanism is related to DEHP-induced oxidative stress leading to apoptosis through mitochondrial fission. We demonstrated that DEHP-induced oxidative stress triggers neuronal cell death via mitochondrial fission in mouse hippocampal HT-22 cells. Furthermore, we identified that peroxiredoxin 5 (Prx5), an antioxidant enzyme induced by DEHP, prevents DEHP-induced mitochondrial fission by inhibiting the production of reactive oxygen species. We conclude that Prx5 may be a promising therapeutic target for mitigating DEHP-induced neuronal cell death.

Thermo-chemical micro-sensing system of a biological model organism C. elegans towards a chemical stimulus

DEHP (Di-ethyl hexyl phthalate), an ubiquitous chemical constituent of plasticizer, cosmetics etc. poses different abnormal neurological and behavioral responses in eukaryotic model organism C. elegans (Caenorhabditis elegans). Based upon such reports, we hypothesized that due to exposure of DEHP, the larval growth of C. elegans was altered and animals went into dauer at high concentrations of exposure at 8.26 ppm. Using chemosensory assay, the orientation of repulsion (− 0.1) of the nematodes were determined with exposure of DEHP at 4.78 ppm and 8.26 ppm. We show that N2 wild type worms display a preferential food choice and search for favorable food, and alter two modes of locomotion (forward and backward) that measures the maximum bending rate of an adult worm. Thermo sensation also plays a crucial role in determining the toxicity level in C. elegans at 15 °C, 20 °C, and 25 °C. Understanding the chemosensory pattern towards a specific chemical for C. elegans, the recent work could shed light in exploring the molecular mechanism involved in the tactile movement of the worms against a specific chemical, thereby making worms a potential biological sensing platform for external stimuli perception.

Phthalate Ester Contamination in Intensively Managed Greenhouse Facilities and the Assessment of Carcinogenic and Non-Carcinogenic Risk: A Regional Study

The contamination status and the potential carcinogenic and non-carcinogenic health risks from six phthalate esters (PAEs), nominated as priority pollutants by the United States Environmental Protection Agency (USEPA), were investigated in 40 typical greenhouses in three large-scale intensive greenhouse production areas in Jingmen city, Hubei province, central China. The total concentrations of PAEs in 40 soil samples and 80 vegetable samples ranged from 919 ± 134 to 7015 ± 475 µg kg−1 (dry weight, DW), and from 387 ± 63, to 11,683 ± 1313 µg kg−1 (DW), respectively. No carcinogenic risk was detected. The heat-map of the hazard quotient (HQ) values indicates the non-carcinogenic risks to children from di-n-butyl phthalate (DBP), at two sampling sites out of the 40, and from diethylhexyl phthalate (DEHP) (20 to young children and three to older children and adults) at 23 of the sites. The contamination risk from PAEs at Pengdun is of concern because only two of the 14 sampling sites selected there showed the non-carcinogenic risk to humans was unclear. The results of this study help to close a long-term knowledge gap resulting from a shortage of experimental data on PAE contamination in intensive greenhouse vegetable production in central China. The inclusion of DEHP in the Chinese list of priority pollutants is recommended, due to its increasing contamination and risk. This study provides valuable information for protected agricultural soil management and risk avoidance. It is a timely reminder to take PAE contamination and associated health risks into consideration, during the planning and introduction of intensively-managed greenhouse production systems.

Lactobacillus plantarum TW1-1 Alleviates Diethylhexylphthalate-Induced Testicular Damage in Mice by Modulating Gut Microbiota and Decreasing Inflammation.

Diethylhexylphthalate (DEHP), acting as an endocrine disruptor, disturbed reproductive health. Here, we evaluated the effects of Lactobacillus plantarum TW1-1 (L. plantarum TW1-1) on DEHP-induced testicular damage in adult male mice. Results showed that oral supplementation of L. plantarum TW1-1 significantly increased the serum testosterone concentration, enhanced the semen quality, and attenuated gonad development defects in DEHP-exposed mice. L. plantarum TW1-1 also alleviated DEHP-induced oxidative stress and inflammatory responses by decreasing the mRNA expression and serum protein concentration of different inflammatory factors [tumor necrosis factor-α, interleukin (IL)-1β and IL-6]. Furthermore, L. plantarum TW1-1 significantly reduced DEHP-induced intestinal hyper-permeability and the increase in the serum lipopolysaccharide level. Gut microbiota diversity analysis revealed that L. plantarum TW1-1 shifted the DEHP-disrupted gut microbiota to that of the control mice. At phylum level, L. plantarum TW1-1 reversed DEHP-induced Bacteroidetes increase and Firmicutes decrease, and restored Deferribacteres in DEHP-exposed mice. Spearman's correlation analysis showed that Bacteroidetes, Deferribacteres, and Firmicutes were associated with DEHP-induced testicular damage. In addition, the ratio of Firmicutes to Bacteroidetes (Firm/Bac ratio) significantly decreased from 0.28 (control group) to 0.13 (DEHP-exposed group), which was restored by L. plantarum TW1-1 treatment. Correlation analysis showed that the Firm/Bac ratio was negatively correlated with testicular damage and inflammation. These findings suggest that L. plantarum TW1-1 prevents DEHP-induced testicular damage via modulating gut microbiota and decreasing inflammation.

Diethylhexyl phthalate removal in full scale activated sludge plants: Effect of operational parameters

Removal of emerging contaminants (ECs) is a serious concern in wastewater industry especially for public acceptance of reclaimed water. Diethylhexyl phthalate (DEHP) is one of the ubiquitous and detectable plasticizers in municipal wastewater across the globe. Water Framework Directive (2000/60/EC) has prioritized it for the establishment of discharge regulations. A cost-effective strategy, especially for developing nations, may be the re-engineering of the existing biological process for the simultaneous removal of ECs and conventional pollutants. Wastewater treatment plants are one of the main sources for DEHP occurrence in surface water. In this study, possible role of activated sludge process operational parameters in effective removal of DEHP was assessed. Principal component analysis of occurrence data showed dissimilarity with the organic and nutrient characteristics of sewage. DEHP concentration in more than half (55%) of treated wastewater samples was more than environmental quality standard value for inland and surface water bodies (1.3 μg/L). At a mixed liquor suspended solid (MLSS) concentration range of 3461–4972 mg/L, overall removal was 23.9 μg/gMLSS.d (92 ± 6%) with biodegraded portion as 22.4 μg/gMLSS.d (85 ± 4%) and sorbed portion of 1.5 μg/gMLSS.d (7 ± 4%). DEHP removal showed an increasing trend at higher oxygen uptake rates (OUR) of sludge with DEHP removal of 8.1 μg DEHP/gMLSS.d (70 ± 6%), in the OUR range of 20-28mgO2/L/h. Increase in overall removal of DEHP showed a positive correlation (r2 = 0.7) with increasing sludge retention time (SRT) and so does the decreasing food to microorganism (F/M) ratio with increasing removal of DEHP (r2 = 0.8). A temperature decrease of 13 °C caused a decrease of 30% in overall removal of DEHP.

Characterizing Airborne Phthalate Concentrations and Dynamics in a Normally Occupied Residence.

Phthalate esters, commonly used as plasticizers, can be found indoors in the gas phase, in airborne particulate matter, in dust, and on surfaces. The dynamic behavior of phthalates indoors is not fully understood. In this study, time-resolved measurements of airborne phthalate concentrations and associated gas-particle partitioning data were acquired in a normally occupied residence. The vapor pressure and associated gas-particle partitioning of measured phthalates influenced their airborne dynamic behavior. Concentrations of higher vapor pressure phthalates correlated well with indoor temperature, with little discernible influence from direct occupant activity. Conversely, occupant-related behaviors substantially influenced the concentrations and dynamic behavior of a lower vapor pressure compound, diethylhexyl phthalate (DEHP), mainly through production of particulate matter during cooking events. The proportion of airborne DEHP in the particle phase was experimentally observed to increase under higher particle mass concentrations and lower indoor temperatures in correspondence with theory. Experimental observations indicate that indoor surfaces of the residence are large reservoirs of phthalates. The results also indicate that two key factors influenced by human behavior-temperature and particle mass concentration-cause short-term changes in airborne phthalate concentrations.

Development of an impedance-based interdigitated biochemical sensor using a multiuser silicon process

An impedance-based interdigitated biochemical sensor is presented in this work that is designed and fabricated using a standard polycrystalline silicon process. The sensor provides a near real-time, non-invasive, label free and rapid detection technique to quantify chemicals and biomarkers in aqueous solutions. The combination of sensor structure and aqueous solution creates an equivalent electrical circuit comprised of constant and variable capacitive and resistive elements such as solution resistance and double-layer capacitance formed at the interface of the electrodes surface and the solution. The equivalent circuit and its elements are used to quantify the concentration of chemicals in an aqueous solution using the impedance of the system. Diethylhexyl phthalate (DEHP) solution is utilized to characterize and analyze the sensor’s response via electrochemical impedance spectroscopy. Finite element analysis and experimental data are used to determine the components of the equivalent circuit. The experimental results show that the sensor is able to detect the concentration of DEHP as low as 0.02 ppm. Using the circuit model and experimental data, the change of double-layer capacitance and solution resistance of the system for different solution concentrations are obtained. The results show that the double-layer capacitance increases with solution concentration, while the solution resistance decreases. The experimental results also verify the electrical circuit model used for the sensing system.

Longitudinal Metabolic Impacts of Perinatal Exposure to Phthalates and Phthalate Mixtures in Mice.

Developmental exposures to phthalates are suspected to contribute to risk of metabolic syndrome. However, findings from human studies are inconsistent, and long-term metabolic impacts of early-life phthalate and phthalate mixture exposures are not fully understood. Furthermore, most animal studies investigating metabolic impacts of developmental phthalate exposures have focused on diethylhexyl phthalate (DEHP), whereas newer phthalates, such as diisononyl phthalate (DINP), are understudied. We used a longitudinal mouse model to evaluate long-term metabolic impacts of perinatal exposures to three individual phthalates, DEHP, DINP, and dibutyl phthalate (DBP), as well as two mixtures (DEHP+DINP and DEHP+DINP+DBP). Phthalates were administered to pregnant and lactating females through phytoestrogen-free chow at the following exposure levels: 25 mg of DEHP/kg of chow, 25 mg of DBP/kg of chow, and 75 mg of DINP/kg of chow. One male and female per litter (n = 9 to 13 per sex per group) were weaned onto control chow and followed until 10 months of age. They underwent metabolic phenotyping at 2 and 8 months, and adipokines were measured in plasma collected at 10 months. Longitudinally, females perinatally exposed to DEHP only had increased body fat percentage and decreased lean mass percentage, whereas females perinatally exposed to DINP only had impaired glucose tolerance. Perinatal phthalate exposures also modified the relationship between body fat percentage and plasma adipokine levels at 10 months in females. Phthalate-exposed males did not exhibit statistically significant differences in the measured longitudinal metabolic outcomes. Surprisingly, perinatal phthalate mixture exposures were statistically significantly associated with few metabolic effects and were not associated with larger effects than single exposures, revealing complexities in metabolic effects of developmental phthalate mixture exposures.

Mothers and children are related, even in exposure to chemicals present in common consumer products

BackgroundPhthalates, bisphenol A (BPA) and triclosan (TCS) are detectable in the vast majority of people. Most humans are continuously exposed to these chemicals due to their presence in food or in everyday consumer products. The measurement of these compounds in family members may help to explore the impact of major lifestyle factors on exposure. Mothers and (young) children are especially interesting to study, as they mostly share considerable parts of daily life together. Materials and methodsPhthalate metabolites, bisphenol A (BPA) and triclosan (TCS) were measured in first morning void urine, collected in mother-child pairs (n = 129) on the same day. The mothers (27-45y) and their children (6-11y) were recruited in the Brussels agglomeration and rural areas of Belgium in the context of the European COPHES-DEMOCOPHES human biomonitoring project. Face-to-face questionnaires gathered information on major exposure sources and lifestyle factors. Exposure determinants were assessed by multiple linear regression analysis. ResultsThe investigated compounds were detectable in nearly all mothers (92.8–100%) and all children (95.2–100%). The range (P90 vs. P10) of differences in urinary concentrations within each age group was for most compounds around 10–20 fold, and was very high for TCS up to 35 and 350-fold in children and mothers respectively. Some participants exceeded the tolerable daily intake guidelines as far as they were available from the European Food Safety Authority (EFSA). Overall, for BPA, the urinary concentrations were similar among both age groups. Most urinary phthalate metabolites were higher in children compared to the mothers, except for monoethyl phthalate (MEP). TCS levels were generally higher in the mothers. Despite the difference in mothers' and children's urinary concentrations, the creatinine-corrected levels were correlated for all biomarkers (Spearman rank r = 0.32 to 0.66, p < 0.001). Furthermore, for phthalates, similar home and lifestyle factors were associated with the urinary concentrations in both age groups: home renovation during last two years or redecoration during the last year for di-ethyl phthalate (DEP); PVC in home for di-n-butyl phthalate (DnBP), di-iso-butyl phthalate (DiBP) and butyl benzyl phthalate (BBzP), and personal care products use for DiBP and DnBP. Based on questionnaire information on general food type consumption patterns, the exposure variability could not be explained. However, comparing the phthalate intake from the current study with earlier assessed Belgian food intake calculations for both ages, food in general was estimated to be the major intake source for di-ethyl hexyl phthalate (DEHP), with diminishing importance for BBzP, DiBP and DnBP. ConclusionOur results confirm, that children and their mothers, sharing diets and home environments, also share exposure in common consumer products related chemicals. By collecting morning urine levels on the same day, and using basic questionnaires, suspected exposure routes could be unraveled.

Effect of hydraulic retention time on micropollutant biodegradation in activated sludge system augmented with acclimatized sludge treating low-micropollutants wastewater

This research investigates the effect of hydraulic retention time (HRT) on micropollutant biodegradation of two-stage activated sludge (AS) system augmented with acclimatized sludge treating low-micropollutants wastewater. The experimental wastewater was a mixture of landfill leachate and agriculture wastewater, and HRT was varied between 24, 18, and 12 h. The results showed that, under 24 h HRT, the micropollutant biodegradation efficiencies were 87–93% for bisphenol A (BPA), 2,6-di-tert-butyl-phenol (2,6-DTBP), di-butyl-phthalate (DBP), di-(ethylhexyl)-phthalate (DEHP); 75–81% for carbamazepine (CBZ), diclofenac (DCF); and 88% for N,N-diethylmeta-toluamide (DEET). The degradation efficiencies were similar under 18 h HRT: 87–93% for BPA, 2,6-DTBP, DBP, DEHP; 75–80% for CBZ, DCF; and 80% for DEET. However, the efficiencies substantially declined under 12 h HRT: 71–93%, 55–60%, and 50%, respectively. Importantly, the findings revealed that HRT plays a crucial part in micropollutant biodegradation of bioaugmented AS system. More specifically, too short an HRT (12 h) results in low micropollutant removal efficiency, and too long an HRT (24 h) contributes to low daily throughput and high treatment operation cost. As a result, moderate HRT (18 h) is operationally and economically optimal for bioaugmented AS system treating low-micropollutants wastewater.

Correction to: Association Between Diethylhexyl Phthalate Exposure and Thyroid Function: A Meta-Analysis by Kim MJ, Moon S, Oh B-C, Jung D, Choi K, and Park YJ. Thyroid 2019;29:183–192. DOI: 10.1089/thy.2018.0051

ThyroidVol. 29, No. 5 CorrectionFree AccessCorrection to: Association Between Diethylhexyl Phthalate Exposure and Thyroid Function: A Meta-Analysis by Kim MJ, Moon S, Oh B-C, Jung D, Choi K, and Park YJ. Thyroid 2019;29:183–192. DOI: 10.1089/thy.2018.0051is erratum ofAssociation Between Diethylhexyl Phthalate Exposure and Thyroid Function: A Meta-AnalysisPublished Online:13 May 2019https://doi.org/10.1089/thy.2018.0051.correxAboutSectionsPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail In the February 2019 issue of Thyroid (vol. 29, no. 2; 183–192) the article entitled “Association Between Diethylhexyl Phthalate Exposure and Thyroid Function: A Meta-Analysis” by Kim et al. requires correction.Figure legends 2–4 mention PFOS, PFOA, and PFHxS instead of MEHP, MEHHP, and MEOHP as discussed in the article. The legends originally read: FIG. 2.Forest plots of the correlation coefficient with corresponding confidence intervals (CIs) for the correlation between perfluorooctane sulfonate (PFOS) and thyroid hormone. (A) Correlation between PFOS and thyrotropin (TSH). (B) Correlation between PFOS and free thyroxine (fT4). (C) Correlation between PFOS and total thyroxine (TT4).FIG. 3.Forest plots of the correlation coefficient with corresponding CIs for the correlation between perfluorooctanoic acid (PFOA) and thyroid hormone. (A) Correlation between PFOA and TSH. (B) Correlation between PFOA and fT4. (C) Correlation between PFOA and TT4.FIG. 4.Forest plots of the correlation coefficient with corresponding CIs for the correlation between perfluorohexane sulfonic acid (PFHxS) and thyroid hormone. (A) Correlation between PFHxS and TSH. (B) Correlation between PFHxS and fT4. (C) Correlation between PFHxS and TT4.The legends should read:FIG. 2. Forest plots of the correlation coefficient with corresponding confidence intervals (CIs) for the correlation between monoethylhexyl phthalate (MEHP) and thyroid hormone. (A) Correlation between MEHP and thyrotropin (TSH). (B) Correlation between MEHP and free thyroxine (fT4). (C) Correlation between MEHP and total thyroxine (TT4).FIG. 3. Forest plots of the correlation coefficient with corresponding CIs for the correlation between mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and thyroid hormone. (A) Correlation between MEHHP and TSH. (B) Correlation between MEHHP and fT4. (C) Correlation between MEHHP and TT4.FIG. 4. Forest plots of the correlation coefficient with corresponding CIs for the correlation between mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) and thyroid hormone. (A) Correlation between MEOHP and TSH. (B) Correlation between MEOHP and fT4. (C) Correlation between MEOHP and TT4.The online version has been corrected to reflect this. The authors apologize for these errors.FiguresReferencesRelatedDetailsRelated articlesAssociation Between Diethylhexyl Phthalate Exposure and Thyroid Function: A Meta-Analysis26 Apr 2019Thyroid Volume 29Issue 5May 2019 InformationCopyright 2019, Mary Ann Liebert, Inc., publishersTo cite this article:Correction to: Association Between Diethylhexyl Phthalate Exposure and Thyroid Function: A Meta-Analysis by Kim MJ, Moon S, Oh B-C, Jung D, Choi K, and Park YJ. Thyroid 2019;29:183–192. DOI: 10.1089/thy.2018.0051.Thyroid.May 2019.752-752.http://doi.org/10.1089/thy.2018.0051.correxPublished in Volume: 29 Issue 5: May 13, 2019PDF download

Mono-(2-ethylhexyl) Phthalate Aggravates Inflammatory Response via Sirtuin Regulation and Inflammasome Activation in RAW 264.7 Cells.

Artificial environmental endocrine disrupting chemicals (EDCs) exert public health concerns. Exposure to EDCs may induce various disorders in the cardiometabolic system. However, the underlying mechanisms remain largely unknown. Over the past decade, an abundance of evidence has emerged demonstrating a close link between cardiometabolic disorders and inflammation. The aim of the present study was to evaluate the immunological effects on macrophages from six EDCs via sirtuin (SIRT) regulation using the murine macrophage RAW 264.7 cell. We studied first the effects of these EDCs, including a series of doses of benzyl butyl phthalate (BBP), bisphenol A (BPA), diethylhexyl phthalate (DEHP), mono-(2-ethylhexyl)phthalate (MEHP), perfluorooctanoate (PFOA), or perfluorooctanesulfonate (PFOS), on SIRT1-7 transcriptional level. Among these EDCs, MEHP significantly decreased all sirtuin genes' expression in a dose-dependent manner. Under MEHP treatment, SIRT activity and protein expression were significantly decreased, while the protein expression of acetylated NF-κB was significantly increased along with significant increases in IL-1β transcription. These results indicate that MEHP may induce the inflammatory response via SIRT-mediated acetylation of NF-κB. Additionally, the enhanced IL-1β secretion in the presence of 50 μM MEHP ( P < 0.01) also supports inflammasome activation (significant ASC and NLRP3 protein augmentation). Both events may be regulated by MEHP induced reactive oxygen species ( P < 0.01). In conclusion, our study suggests for the first time that EDCs differentially modulate sirtuins' gene expression levels in macrophages and that a specific phthalate MEHP can lead to an increased inflammatory response by impairing vital epigenetic regulators and inflammasome activation.

Analysis of Endocrine-Disrupting Compounds from Cheese Samples Using Pressurized Liquid Extraction Combined with Dispersive Liquid–Liquid Microextraction Followed by High-Performance Liquid Chromatography

Simultaneous extraction and preconcentration of five endocrine disrupting compounds including di-butyl phthalate, di-iso-nonyl phthalates, di-ethylhexyl phthalate, di-ethylhexyl adipate, and bisphenol A from cheese have been developed using pressurized liquid extraction combined with dispersive liquid–liquid extraction followed by high-performance liquid chromatography-diode array detector. In this method, initially, the analytes are extracted into a water-miscible extraction solvent (acetone) at high pressure (1000 psi) and temperature (70 °C) in the presence of carbon tetrachloride as a modifier. After extraction, a volume of the organic phase is removed and dispersed into deionized water. The cloudy solution was centrifuged, and the sedimented phase is used in analysis. Efficient parameters were optimized using one-parameter-at-one-time strategy, and low limits of detection and quantification in the ranges of 0.82–3.1 and 2.8–10 ng g−1 were obtained, respectively. Relative standard deviations lower than 8% show an acceptable precision for the present method. The enrichment factors and extraction recoveries in the ranges of 259–319 and 78–96% were achieved, respectively. Lastly, some real samples were analyzed and di-butyl phthalate and di-ethylhexyl phthalate were found in them.

Mono-2-ethylhexyl phthalate induces the expression of genes involved in fatty acid synthesis in HepG2 cells

Mono-2-ethylhexyl phthalate (MEHP) is a major bioactive metabolite in the widely used industrial plasticizer diethylhexyl phthalate (DEHP) that has been found to be toxic to the liver. The aim of this study is to determine whether MEHP exposure can change the expression of fatty acid metabolism-related genes in HepG2 cells, which might be related to non-alcoholic fatty liver disease (NAFLD). The results revealed that exposure to MEHP promoted lipid accumulation in HepG2 cells. The levels of intracellular triglycerides in the hepatocytes increased after exposure to 0.8–100 μM MEHP for 24 h and 48 h. The genetic expressions of SREBP-1c, ChREBP, ACC1, FASN, and SCD significantly increased at 6 h after exposure to MEHP. At 24 h, the expression of the SREBP-1c and ChREBP genes remained increased, while the expression of the FASN and SCD genes decreased. At 48 h, the expression of SREBP-1c, ChREBP, ACC1, FASN, and SCD decreased. Furthermore, the levels of proteins including ACC1, FASN, SCD, and ChREBP (except SREBP-1c) increased at 24 h. These findings suggest that MEHP exposure can promote fatty acid synthesis in hepatocytes by regulating the expression of relevant genes and proteins, contributing to NAFLD.

Prenatal Exposure to Bisphenol A and Diethylhexyl Phthalate Induces Hyperprolactinemia in Female offspring

Exposure to endocrine disrupting chemicals (EDC) such as Bisphenol A (BPA) and Diethylhexyl Phthalate (DEHP) are widespread affecting people of all ages. Pregnant women who are exposed to these chemicals through the use of personal care products and plastics invariably expose their fetus to these chemicals as well. Female offspring are then exposed to endogenous estrogens from menarche till menopause and usually, in their prime years, they are also exposed to estrogens through oral contraceptives. This places them at increased risk of developing hyperprolactinemia which causes infertility. In order to mimic real‐life exposures, we developed the “dual exposure paradigm” where we administered saline, 5μg/Kg BW of BPA, 7.5mg/kg BW of DEHP or a combination of BPA+DEHP to pregnant Sprague Dawley rats from day 6–21 of gestation. Female offspring were sham implanted or implanted with slow release estradiol‐17β (E2) pellets for 90 days when they were 3 months old. At the end of E2 treatment, animals were sacrificed, and the brain was removed, frozen and sectioned. We hypothesized that the dual exposure to EDCs and E2 would decrease dopamine (DA) levels in the median eminence of the hypothalamus to increase prolactin levels. The median eminence was microdissected from the brains and DA levels were measured using HPLC‐EC. Serum prolactin levels were assessed by EIA. DA levels in E2‐treated control rats were significantly reduced compared to sham‐implanted rats (p&lt;0.001). Prenatal exposure to EDCs produced a modest reduction in DA levels in sham implanted rats (p&lt;0.05) but decreased further with E2 treatment (p&lt;0.001). Prolactin levels in control animals were significantly higher in E2 implanted rats compared to sham(p&lt;0.05). Prolactin levels in EDC‐exposed rats were variable and were higher than normal in both sham and E2 treated animals. These results indicate that dual exposure to EDC and E2 is able to affect TIDA activity and induce hyperprolactinemia in female offspring. This could have implications in the development of mammary and pituitary tumors.Support or Funding InformationSupported by UGA research foundation and startup funds.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Prenatal Exposure to Bisphenol A and Diethylhexyl Phthalate Induces Apoptosis in the Thymus of Male and Female Offspring

Bisphenol A (BPA) and Diethylhexyl Phthalate (DEHP) are common environmental endocrine disrupting chemicals (EDCs) that exert a range of potential adverse health effects. EDC exposure can occur in utero and during early postnatal life, when organ systems are differentiating resulting in a number of disorders in adulthood. The aim of this study was to evaluate the immunotoxic effect of prenatal exposure to individual and combinations of BPA and DEHP on male and female rat thymus. From gestational day 6 till 21, Sprague Dawley dams were orally administered either saline (control; n=7), BPA (5μg/Kg BW; n=7), DEHP (7.5mg/Kg BW; n=7), or a mixture of BPA and DEHP (B+D; n=7). Male and female offspring were sacrificed at 16 weeks of age. Thymus and spleen were dissected, weighed, and stored for further processing. Our data showed that spleen weight to body weight (BW) ratio of EDC treated offspring were comparable to those from age‐matched control rats. However, male offspring (but not females) that were prenatally exposed to BPA alone exhibited a 40% decrease (p&lt;0.01) and those exposed to DEHP alone had a 27% reduction in thymus/BW ratio (p&lt;0.05). To understand if prenatal EDC exposure was promoting early thymus involution through apoptosis, we performed Terminal deoxynucleotidyl transferase‐dUTP nick end labeling (TUNEL) staining of nicked DNA on thymic sections. There was significant apoptosis in the thymic cortex in both male and female offspring that were prenatally exposed to individual EDCs. Apoptosis was hardly detected in the medullary region. Apoptosis in the B+D group was markedly reduced compared to individual EDC exposures. These results suggest that prenatal exposure to even low BPA and moderate DEHP levels can promote apoptosis in the thymus. This could possibly affect immune functions in adulthood. Interestingly, exposure to a mixture of these EDCs did not produce any significant change in apoptosis in the thymus.Support or Funding InformationSupported by UGA Research Foundation and start‐up funds.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Fish and Seabird Gut Conditions Enhance Desorption of Estrogenic Chemicals from Commonly-Ingested Plastic Items.

Plastic is ingested by over 100 bird species and 40 fish species. Once ingested, plastic may release endocrine-disrupting plastic additives in the animal; however, amounts transferred are poorly characterized. We exposed 16 commonly ingested plastic items to fish and seabird laboratory gut mimic models using the digestive enzyme pepsin at pH 2 and shook them for 16 h at either 28 °C (in saltwater) for fish or 40 °C (in freshwater) for seabirds. Gut liquid was then evaluated for estrogen receptor activity using an in vitro cell line, and plastic-additive concentrations were quantified using ultrahigh-performance liquid chromatography/tandem mass spectrometry. Both seabird ( p < 0.0001) and fish gut conditions ( p < 0.0001) significantly enhanced the biological estrogenicity of expanded polystyrene, polyethylene shopping bag, and polypropylene string relative to controls, resulting in up to a 10.6-fold increase in estrogenicity. Out of 12 plastic additives analyzed, bisphenol A (BPA) (204 ± 129%) and diethylhexyl phthalate (DEHP) (175 ± 97%) concentrations were significantly increased in seabird gut conditions relative to control and butylbenzyl phthalate (BBP) (132 ± 68%) was significantly increased in fish gut conditions relative to control. BPA, DEHP, and BBP did not adequately account for the increase in biological estrogenicity, suggesting that uncharacterized plastic additives may have been enhanced by gut conditions.

Independent and combined effects of diethylhexyl phthalate and polychlorinated biphenyl 153 on sperm quality in the human and dog

A temporal decline in human and dog sperm quality is thought to reflect a common environmental aetiology. This may reflect direct effects of seminal chemicals on sperm function and quality. Here we report the effects of diethylhexyl phthalate (DEHP) and polychlorinated biphenyl 153 (PCB153) on DNA fragmentation and motility in human and dog sperm. Human and dog semen was collected from registered donors (n = 9) and from stud dogs (n = 11) and incubated with PCB153 and DEHP, independently and combined, at 0x, 2x, 10x and 100x dog testis concentrations. A total of 16 treatments reflected a 4 × 4 factorial experimental design. Although exposure to DEHP and/or PCB153 alone increased DNA fragmentation and decreased motility, the scale of dose-related effects varied with the presence and relative concentrations of each chemical (DEHP.PCB interaction for: DNA fragmentation; human p < 0.001, dog p < 0.001; Motility; human p < 0.001, dog p < 0.05). In both human and dog sperm, progressive motility negatively correlated with DNA fragmentation regardless of chemical presence (Human: P < 0.0001, r = −0.36; dog P < 0.0001, r = −0.29). We conclude that DEHP and PCB153, at known tissue concentrations, induce similar effects on human and dog sperm supporting the contention of the dog as a sentinel species for human exposure.

Comparing the effects of diethylhexyl phthalate and dibutyl phthalate exposure on hypertension in mice

Epidemiological studies have shown that high molecular weight phthalates (HMW) such as diethylhexyl phthalate (DEHP), are associated with hypertension in humans, while low molecular weight phthalates (LMW) such as dibutyl phthalate (DBP), have hardly any impact on the elevation of blood pressure. However, the molecular mechanisms responsible for this difference are not completely understood. In this experiment, mice were exposed to 0.1/1/10 mg/kg/day DEHP and 0.1/1/10 mg/kg/day DBP for 6 weeks, and their blood pressure was monitored using the tail pressure method. The results showed that exposure to DEHP dosages of 1 or 10 mg/kg/day resulted in a sharp increase in blood pressure, while exposure to DBP did not induce any significant changes in blood pressure. Investigating the renin-angiotensin-aldosterone system (RAAS) and NO pathway in mice exposed to DEHP, we found that levels of angiotensin-converting enzyme (ACE) and angiotensin II (AngII) increased with increasing exposure to DEHP, and the expression of nitric oxide synthase (eNOS) and the level of NO decreased. Treatment with ACE inhibitor (ACEI) to block the ACE pathway inhibited the enhancement of RAAS expression, inhibited the increase in blood pressure, and inhibited the decrease in NO levels induced by DEHP. However, the expression of ACE, AngII, AT1R, and eNOS in the DBP treatment groups showed no significant changes. When examining estradiol in vivo, we found that exposure to DBP resulted in a significant increase in the level of estradiol, while exposure to DEHP did not lead to a significant change. When ICI182780 was used to block the estradiol receptors, any increase in the level of NO induced by DBP exposure, was inhibited. These results indicate that exposure to DEHP induces an increase in mouse blood pressure through RAAS, and the different effects of DEHP and DBP on blood pressure are partly due to the different estradiol levels induced by DEHP and DBP.