Exposure to DEHP decreased four fatty acid levels in plasma of prepartum mice

Endocrine adverse effects of mono(2-ethylhexyl) phthalate and monobutyl phthalate in male pubertal rats

Considering that research of adverse effects of mono(2-ethylhexyl) phthalate (MEHP) and monobutyl phthalate (MBP), two key metabolites of the most common phthalates used as plasticisers in various daily-life products, has been scattered and limited, the aim of our study was to provide a more comprehensive analysis by focusing on major organ systems, including blood, liver, kidney, and pancreas in 66 male pubertal rats randomised into eleven groups of six. The animals were receiving either metabolite at doses of 25, 50, 100, 200, or 400 mg/kg bw a day by gavage for 28 days. The control group was receiving corn oil. At the end of the experiment, blood samples were collected for biochemical, haematological, and immunological analyses. Samples of kidney, liver, and pancreas were dissected for histopathological analyses. Exposure to either compound resulted in increased liver and decreased pancreas weight, especially at the highest doses. Exposed rats had increased ALT, AST, glucose, and triglyceride levels and decreased total protein and albumin levels. Both compounds increased MCV and decreased haemoglobin levels compared to control. Although they also lowered the insulin level, exposed rats had negative islet cell and insulin antibodies, same as control. Treatment-related histopathological changes included sinusoidal degeneration in the liver, glomerular degeneration in the kidney, and degeneration of pancreatic islets. Our findings document toxic outcomes of MEHP and MBP on endocrine organs in male pubertal rats but also suggest the need for additional studies to better understand the mechanisms behind adverse effects in chronic exposure.

Metabolomics and Data-Driven Bioinformatics Revealed Key Maternal Metabolites Related to Fetal Lethality via Di(2-ethylhexyl)phthalate Exposure in Pregnant Mice

We performed serum metabolome analysis of di(2-ethylhexyl)phthalate (DEHP)-exposed and control pregnant mice. Pregnant mice (n = 5) were fed a DEHP-containing diet (0.1% or 0.2% DEHP) or a normal diet (control) from gestational days 0-18. After maternal exposure to 0.2% DEHP there were no surviving fetuses, indicating its strong fetal lethality. There were no significant differences in the numbers of fetuses and placentas between the 0.1% DEHP and control groups, although fetal viability differed significantly between them, suggesting that maternal exposure to 0.1% DEHP could inhibit fetal growth. Metabolomics successfully detected 169 metabolites in serum. Principal component analysis (PCA) demonstrated that the three groups were clearly separated on PCA score plots. The biological interpretation of PC1 was fetal lethality, whereas PC2 meant metabolic alteration of pregnant mice via DEHP exposure without fetal lethality. In particular, the first component was significantly correlated with fetal viability, demonstrating that maternal metabolome changes via DEHP exposure were strongly related to fetal lethality. Levels of some amino acids were significantly increased in the DEHP-exposed groups, whereas those of some fatty acids, nicotinic acid, and 1,5-anhydroglucitol were significantly decreased in the DEHP groups. DEHP-induced increases in glycine levels could cause fetal neurological disorders, and decreases in nicotinic acid could inhibit fetal growth. In addition, a machine-learning Random forest could determine 16 potential biomarkers of DEHP exposure, and data-driven network analysis revealed that nicotinic acid was the most influential hub metabolite in the metabolic network. These findings will be useful for understanding the effects of DEHP on the maternal metabolome in pregnancy and their relationship to fetal lethality.

Mediation effects of thyroid function in the associations between phthalate exposure and lipid metabolism in adults

Phthalates are a group of industrial chemicals widely used in everyday products including cosmetics, food packaging and containers, plastics, and building materials. Previous studies have indicated that urinary phthalate metabolites are associated with metabolic effects including those on lipid metabolism, but the results are mixed. Furthermore, whether thyroid function mediates the association between phthalate exposure and lipid metabolism remains unclear. In the present study, we explored whether changes in thyroid function markers mediate the associations between phthalate exposure and lipid metabolism indicators in Taiwanese adults. The cross-sectional data were obtained from the Taiwan Environmental Survey for Toxicants conducted in 2013. Levels of 11 urinary phthalate metabolites, levels of 5 thyroid hormones, and 8 indicators of lipid metabolism were assessed in 222 Taiwanese adults. The relationships of urinary phthalate metabolite levels with serum thyroid hormone levels and lipid metabolism indicators were explored using multiple regression models. Mediation analysis was conducted to evaluate the role of thyroid function in the association between phthalate exposure and lipid metabolism. The metabolite of di(- 2-ethylhexyl) phthalate (∑DEHPm) exhibited a significant positive association with the lipid metabolite indicator of high-density lipoprotein cholesterol (HDL-C; β = 0.059, 95% confidence interval [CI] = 0.009, 0.109) in adults, and the thyroid function indicator thyroxine (T₄) had a significant negative association with the metabolite ∑DEHPm (β = - 0.059, 95% CI = - 0.101, - 0.016) and a significant negative association with HDL-C (β = - 0.284, 95% CI = - 0.440, - 0.128). The T₄ indirect effect was 0.015 (95% CI = - 0.0087, 0.05), and the mediation effect was 32.2%. Our results support the assumption that exposure to phthalates influences the homeostasis of lipid metabolism by interfering with thyroid function.

Association of Maternal Total Cholesterol With SGA or LGA Birth at Term: the Japan Environment and Children's Study

CONTEXT

Maternal cholesterol is important for fetal development. Whether maternal serum total cholesterol (maternal TC) levels in midpregnancy are associated with small (SGA) or large (LGA) for gestational age independent of prepregnancy body mass index (BMI) and weight gain during pregnancy is inconclusive.

OBJECTIVE

This work aimed to prospectively investigate the association between maternal TC in midpregnancy and SGA or LGA.

METHODS

The Japan Environment and Children's Study is a nationwide prospective birth cohort study in Japan. Participants in this study included 37 449 nondiabetic, nonhypertensive mothers with singleton birth at term without congenital abnormalities. Birth weight for gestational age less than the 10th percentile and greater than or equal to the 90th percentile were respectively defined as SGA and LGA by the Japanese neonatal anthropometric charts.

RESULTS

The mean gestational age at blood sampling was 22.7 ± 4.0 weeks. After adjustment for maternal age, sex of child, parity, weight gain during pregnancy, prepregnancy BMI, smoking, alcohol drinking, blood glucose levels, household income, and study areas, 1-SD decrement of maternal TC was linearly associated with SGA (odds ratio [OR]: 1.20; 95% CI, 1.15-1.25). In contrast, 1-SD increment of maternal TC was linearly associated with LGA (OR: 1.13; 95% CI, 1.09-1.16). Associations did not differ according to prepregnancy BMI and gestational weight gain (P for interaction > .20).

CONCLUSION

Maternal TC levels in midpregnancy were associated with SGA or LGA in a Japanese cohort. It may help to predict SGA and LGA. Favorable maternal lipid profiles for fetal development must be explored.

Mechanistic insight into toxicity of phthalates, the involved receptors, and the role of Nrf2, NF-κB, and PI3K/AKT signaling pathways

The wide use of phthalates, as phthalates are used in the manufacturing of not only plastics but also many others goods, has become a main concern in the current century because of their potency to induce deleterious effects on organism health. The toxic effects of phthalates such as reproductive toxicity, cardiotoxicity, hepatotoxicity, nephrotoxicity, teratogenicity, and tumor development have been widely indicated by previous experimental studies. Some of the important mechanisms of toxicity by phthalates are the induction and promotion of inflammation, oxidative stress, and apoptosis. Awareness of the involved molecular pathways of these mechanisms will permit the detection of exact molecular targets of phthalates to protect or treat their toxicity. Up to now, various transcription factors and signaling pathways have been associated with phthalate-induced toxicity which by influencing on nuclear surface and the expression of different genes can alter cell hemostasis. In different studies, the role of nuclear factor erythroid 2-related factor 2 (Nrf2), nuclear factor-κB (NF-κB), and phosphatidylinositol-3-kinase (PI3K)/AKT signaling pathways in processes of oxidative stress, inflammation, apoptosis, and cancer has been shown following exposure to phthalates. In the present review, we aim to survey experimental studies (in vitro and in vivo) in order to show firstly the most involved receptors and also the importance and the role of the mentioned signaling pathways in phthalate-induced toxicity, and with considering this point, the future studies can focus on these molecular targets as a strategic method to reduce environmental chemicals-induced toxicity especially phthalates toxic effects.

Di(2-ethylhexyl) adipate plasticizer triggers hepatic, brain, and cardiac injury in rats: Mitigating effect of Peganum harmala oil

Di(2-ethylhexyl) adipate (DEHA) is a widely used plasticizer and prevalent environmental contaminant. In this study, DEHA concentrations in the milk, cheese, and butter samples wrapped with food-grade commercial polyethylene films and stored at 4 °C for 30 days were detected using gas chromatographic analysis. Also, the effects of exposure to a high dose of DEHA for a long duration on the liver, brain, and heart of Wistar rats were assessed. Besides, the possible beneficial effect of Peganum harmala oil (PGO), in relieving DEHA induced adverse effects was explored. For this purpose, four groups (8 rats/group) were orally given physiological saline, PGO (320 mg/kg bwt), DEHA (2000 mg/kg bwt), or PGO + DEHA for 60 days. The results revealed that the DEHA concentrations in the tested dairy products were ordered as follows: (butter > cheese > milk). Notably, the detected levels in butter were higher than the specific migration limit in foods. DEHA induced a significant increase in the serum levels of glucose, alanine transaminase, aspartate transaminase, acetylcholine esterase, creatine kinase-myocardium bound, malondialdehyde, tumor necrosis factor-α, and interleukin-1β. But, significant hypoproteinemia, hypoalbuminemia, hypoglobulinemia, and hypocholesterolemia were evident following DEHA exposure. A significant reduction in the serum level of superoxide dismutase, reduced glutathione, and brain-derived neurotrophic factor was recorded. Besides, a significant downregulation in hepatic CYP2E1, brain glial fibrillary acidic protein, and cardiac troponin I gene expression was noticed. Moreover, DEHA exposure induced a significant decrease in Bcl-2 immunolabeling, but Caspase-3 immunoexpression was increased. On the contrary, PGO significantly recused DEHA injurious impacts. Therefore, PGO could represent a promising agent for preventing DEHA-induced hepatotoxicity, neurotoxicity, and cardiotoxicity.

The role of epigenetics in the reproductive toxicity of environmental endocrine disruptors

Environmental endocrine disruptors (EEDs) seriously endanger human health by interfering with the normal function of reproductive systems. In males, EEDs can affect sperm formation and semen quality as well spermatogenesis, ultimately reducing fertility. In females, EEDs can affect uterine development and the expression levels of reproduction-related genes, ultimately reducing female fertility and the normal development of the fetus. There are a large number of putative mechanisms by which EEDs can induce reproductive toxicity, and many studies have shown the involvement of epigenetics. In this review, we summarize the role of DNA methylation, noncoding RNAs, genomic imprinting, chromatin remodeling and histone modification in the reproductive toxicity of EEDs.

Urinary concentrations of phthalates in relation to circulating fatty acid profile in National Health and Nutrition Examination Survey, 2003-2004 and 2011-2012

Animal studies have suggested that phthalate exposure alters the fatty acid composition of blood plasma. Therefore, we conducted an epidemiological study to examine whether urinary concentrations of phthalates are correlated with circulating fatty acids in the general US population. The 2003-2004 and 2011-2012 National Health and Nutrition Examination Survey were used in this study. Ten urinary phthalate metabolites and 23 fatty acids were measured. Fatty acid patterns were identified using principal component analysis (PCA) with an eigenvalue greater than 1. A two-step analysis was performed. We first performed multivariable linear regressions to evaluate whether urinary phthalate metabolites were related to the PCA-derived components of blood fatty acid levels. Then we performed multivariable linear regressions to investigate each of the fatty acids that were suggestively correlated with some of the phthalates in PCA. There were 994 participants (51.91% women). As for men, after adjustments for potential confounding factors, MECPP, MEHHP, and ∑DEHP were all positively correlated with gamma-linolenic, myristoleic, and myristic acids; both MEHHP and ∑DEHP were positively correlated with stearic acid; MMP was positively correlated with docosahexaenoic acid. As for women, MMP was negatively correlated with docosanoic, lignoceric, and arachidic acids; MBzP was negatively correlated with docosahexaenoic acid; both MEHP and MCPP were negatively correlated with docosatetraenoic acid; MEHP was negatively correlated with arachidonic acid, and MCPP was negatively correlated with docosapentaenoic-6 acid. Our findings support that phthalates may be correlated with circulating fatty acids.

Responses of Microbial Community to Di-(2-ethylhcxyl) Phthalate Contamination in Brown Soil

Di-(2-ethylhcxyl) phthalate (DEHP) is applied as plasticizer, which results in the pollution of environment. In this study, the effects of DEHP on soil microbial functions, structure and genetic diversity were investigated. The concentration of DEHP in the soil were 0, 0.1, 1, 10 and 50 mg/kg, and the experimental period were 28 days. DEHP reduced the quantity, abundance, species dominance and homogeneity of soil microbes during the first 14 days. In addition, microbial utilization efficiency of carbon (carbohydrates, aliphatics, amino acids, metabolites) was impacted after 28 days, though the effects gradually weakened. Based on denaturing gradient gel electrophoresis and clone library analysis, in the presence of DEHP, the dominant microbes in the DEHP-contaminated soil were Sphingomonas and Bacillus, which belonged to the Acidobacteria and Proteobacteriav, respectively. With 0.1 or 1 mg/kg of DEHP, the relative abundances of Acidobacteria were higher, and with 10 or 50 mg/kg of DEHP, the relative abundances of Proteobacteria were higher.

Associations of a mixture of urinary phthalate metabolites with blood lipid traits: A repeated-measures pilot study

Evidence is available about the associations of phthalates or their metabolites with blood lipids, however, the mixture effects of multiple phthalate metabolites on blood lipid traits remain largely unknown. In this pilot study, 106 individuals at three age groups of <18, 18- and ≥60 years were recruited from the residents (n = 1240) who were randomly selected from two communities in Wuhan city, China. The participants completed the questionnaire survey and physical examination as well as provided urine samples in the winter of 2014 and the summer of 2015. We measured urinary levels of nine phthalate metabolites using a high-performance liquid chromatography-tandem mass spectrometry. We estimated the associations of individual phthalate metabolite with blood lipid traits by linear mixed effect (LME) models, and assessed the overall association of the mixture of nine phthalate metabolites with blood lipid traits using Bayesian kernel machine regression (BKMR) models. LME models revealed the negative association of urinary mono-2-ethylhexyl phthalate (MEHP) with total cholesterol (TC) as well as of urinary mono-benzyl phthalate or urinary MEHP with low density lipoprotein cholesterol (LDL-C). BKMR models revealed the negative overall association of the mixture of nine phthalate metabolites with TC or LDL-C, and DEHP metabolites (especially MEHP) had a greater contribution to TC or LDL-C levels than non-DEHP metabolites. The findings indicated the negative overall association of the mixture of nine phthalate metabolites with TC or LDL-C. Among nine phthalate metabolites, MEHP was the most important component for the changes of TC or LDL-C levels, implying that phthalates exposure may disrupt lipid metabolism in the body.

Influence of sociodemographic, lifestyle and genetic characteristics on maternal DHA and other polyunsaturated fatty acid status in pregnancy: A systematic review

INTRODUCTION

Omega-3 DHA is important for the prevention of preterm birth, however there is limited knowledge of the determinants of omega-3 status during pregnancy. The primary objective of this systematic review was to synthesise data from existing studies assessing relationships between sociodemographic, diet, lifestyle and genetic factors and maternal DHA status.

MATERIALS AND METHODS

The Medline, Embase, Amed, and CINAHL databases were searched for studies reporting measures of maternal omega-3 status and a sociodemographic/lifestyle/genetic characteristic.

RESULTS

Twenty-two studies were included in the final analyses. Higher dietary fish consumption/PUFA intake, higher education level and an older maternal age were associated with higher maternal omega-3 status. Higher alcohol intake, smoking and FADS genotype were each associated with lower maternal omega-3 status.

DISCUSSION

Differences in findings between studies make it difficult to draw clear conclusions about the relationship between these factors and maternal omega-3 DHA status, although socioeconomic status may play a role.

Seminal plasma metabolome in relation to semen quality and urinary phthalate metabolites among Chinese adult men

BACKGROUND

A growing body of evidence has found links between endocrine disruptor phthalates and male reproductive disorders, but the mechanisms underlying these relationships are poorly known. Seminal plasma metabolomes may mediate associations of phthalate exposure with impaired semen quality.

OBJECTIVE

To identify seminal plasma metabolomes associated with poor semen quality and evaluate their associations with urinary phthalate metabolites among 660 Chinese adult men.

METHOD

The seminal plasma metabolic profiles were acquired using an untargeted approach based on liquid chromatography-high resolution mass spectrometry. We explored the differences in seminal plasma metabolites between participants with poor and good semen quality and evaluated cross-sectional associations between discriminatory metabolic biomarkers and urinary phthalate metabolites.

RESULTS

Differences between poor and good semen quality groups were observed in relation to 25 seminal plasma metabolites, mostly related to the metabolism of polyunsaturated fatty acids (PUFA) and acylcarnitine (all p < 0.05). After adjusting for various confounders and multiple tests, metabolites were all significantly associated with one or more individual sperm quality parameters (motility, concentration, total count, and morphology) (all p < 0.05). Among identified metabolic biomarkers, seminal plasma L-palmitoylcarnitine, linoelaidyl carnitine, and oleic acid were inversely associated with urinary mono-(2-ethylhexyl) phthalate (MEHP), and seminal plasma L-acetylcarnitine was inversely associated with the proportion of di-(2-ethylhexyl)-phthalate metabolites (DEHP) excreted as MEHP in urine (%MEHP) (all p < 0.05). Mediation analysis revealed that oleic acid and L-acetylcarnitine mediated significant proportions (6.7% and 17%, respectively) of the positive associations between urinary DEHP metabolites and the percentage of spermatozoa with an abnormal head.

CONCLUSIONS

Elevated urinary phthalate metabolites may impact semen quality by causing metabolic disorders of seminal plasma PUFAs and acylcarnitine. These pathways warrant further investigation.

Phthalate induced oxidative stress and DNA damage in earthworms (Eisenia fetida)

Phthalates (phthalic acid esters) have been widely applied as plasticizers. They are ubiquitous contaminants in soils, thereby posing a threat to human health. In this study, ecotoxicological effects of three typical PAEs (dimethyl phthalate-DMP, di-n-octyl phthalate-DOP and butyl benzyl phthalate-BBP) were investigated. As a biological indicator, earthworms (Eisenia fetida) were exposed to phthalates at various doses (0, 0.1, 1, 10 and 50 mg/kg) for different times (7, 14, 21, and 28 d). We evaluated the effects of phthalates on reactive oxygen species (ROS) generation, antioxidant enzymes (superoxide dismutase-SOD, peroxidase-POD and catalase-CAT) activities, glutathione S-transferase enzyme (GST) activity, malondialdehyde (MDA) content and DNA damage. Results showed that ROS content increased with increasing phthalates, whereas ROS content generally increased and then decreased with exposure time. However, antioxidant enzymes activities in earthworms displayed different trends. The GST activity in high-dose treatment group was significantly activated. For DMP and DOP, lipid peroxidation mainly occurred between 14 and 28 d, while for BBP, it primarily existed after 7 d and then disappeared after 28 d. Besides, comet assay indicated that there was a dose-response relationship between the DNA damage and phthalate dose, following DMP > DOP > BBP. Given their toxicity, it is important to understand the mechanisms associated with their eco-toxicity and to reduce their adverse impacts on the environment.

Di(2-ethylhexyl) phthalate-induced toxicity and peroxisome proliferator-activated receptor alpha: a review

The plasticizer di(2-ethylhexyl) phthalate (DEHP) has been widely used in the manufacture of polyvinyl chloride-containing products such as medical and consumer goods. Humans can easily be exposed to it because DEHP is ubiquitous in the environment. Recent research on the adverse effects of DEHP has focused on reproductive and developmental toxicity in rodents and/or humans. DEHP is a representative of the peroxisome proliferators. Therefore, peroxisome proliferator-activated receptor alpha (PPARα)-dependent pathways are the expected mode of action of several kinds of DEHP-induced toxicities. In this review, we summarize DEHP kinetics and its mechanisms of carcinogenicity and reproductive and developmental toxicity in relation to PPARα. Additionally, we give an overview of the impacts of science policy on exposure sources.

Effect of the TYK-2/STAT-3 pathway on lipid accumulation induced by mono-2-ethylhexyl phthalate

BACKGROUND

Mono-2-ethylhexyl phthalate (MEHP), an important metabolite of di (2-ethylhexyl) phthalate (DEHP), can induce lipid metabolic disorder. Previous studies have shown that MEHP promotes 3T3-L1 cell differentiation; however, the underlying mechanism is unclear. The present study was performed to investigate the effect of the TYK-2/STAT-3 pathway on lipid accumulation induced by MEHP.

METHODS

A 3T3-L1 precursor adipocyte differentiation model was exposed to MEHP. 3-Isobutyl-1-methylxanthine (IBMX), dexamethasone (DEX), and insulin were used to establish the 3T3-L1 precursor adipocyte differentiation model. Then the model cells were exposed to MEHP for 8 d. The lipid droplet formation in 3T3-L1 cells was determined with Oil-Red-O staining, and isopropyl alcohol was used to extract the lipid droplets for quantification. Flow cytometry was used to detect the intracellular reactive oxygen species (ROS) and mitochondrial membrane potential. Quantitative real-time polymerase chain reaction (qPCR) was used to detect mRNA expression, and western blotting was used to detect the expression of proteins encoded by TYK-2/STAT-3 pathway genes and adipogenesis-related genes.

RESULTS

MEHP treatment, compared with the control treatment, significantly promoted the differentiation of 3T3-L1 cells and increased the expression of STAT-3 mRNA and protein and P-STAT3 protein in the cells. In addition, MEHP down-regulated the phosphorylation of STAT-3 in mitochondria. MEHP was found to influence the mitochondrial membrane potential and intracellular ROS levels.

CONCLUSION

MEHP may affect adipocyte differentiation and lead to lipid accumulation through the TYK-2/STAT-3 pathway.

In utero exposure to di(2-ethylhexyl)phthalate suppresses blood glucose and leptin levels in the offspring of wild-type mice

Exposure of pregnant mice to di(2-ethylhexyl)phthalate (DEHP) induces maternal lipid malnutrition and decreases the number of live fetuses/pups. In this study, we aimed to clarify the relationship between maternal lipid malnutrition and the nutritional status of the neonatal, lactational, and adult offspring, as well as the role of peroxisome proliferator-activated receptor α (PPARα) in these relationships. Sv/129 wild-type (mPPARA), Ppara-null, and PPARα-humanized (hPPARA) mice were fed diets containing 0, 0.01, 0.05, or 0.1% DEHP in utero and/or during the lactational stage. The male offspring were killed on postnatal day 2 or 21, or after 11 weeks. Exposure to either 0.05% or 0.1% DEHP during both the in utero and lactational periods decreased serum glucose concentrations in 2-day-old mPPARA offspring. These dosages also decreased both serum and plasma leptin levels in both 2- and 21-day-old mPPARA offspring. In contrast, exposure to DEHP only during the lactational period did not decrease leptin levels, suggesting the importance of in utero exposure to DEHP. Exposure to 0.05% DEHP during the in utero and lactational periods also increased food consumption after weaning in both mPPARA and hPPARA mice; this was not observed in Ppara-null offspring. In conclusion, in utero exposure to DEHP induces neonatal serum glucose malnutrition via PPARα. DEHP also decreases serum and plasma leptin concentrations in offspring during the neonatal and weaning periods, in association with PPARα, which presumably results in increased of food consumption after weaning.

Exposure to phthalates is associated with lipid profile in peripubertal Mexican youth

Animal models indicate that endocrine disrupting chemicals (EDCs) affect circulating lipid concentrations by interfering with hepatic fatty acid oxidation. Little is known of the relationship between EDC exposure and lipid profile in humans. We measured bisphenol A (BPA) and 9 phthalate metabolites in maternal urine collected at up to three time points during pregnancy as a measure of in utero exposure, and in the child's urine at 8-14 years as a measure of concurrent, peripubertal exposure among 248 participants of a Mexico City pre-birth cohort. We used linear regression to examine relations of BPA and phthalate exposure with peripubertal serum lipids, while also adjusting for child age, sex, and specific gravity. While in utero EDC exposure was not associated with lipid profile, higher concurrent levels of mono-3-carboxypropyl phthalate (MCPP), monoethyl phthalate (MEP), and dibutyl phthalate metabolites (DBP) corresponded with lower total cholesterol and low-density lipoprotein (LDL-C) in boys; e.g., an interquartile range increment in MCPP corresponded with 7.4% (2.0%, 12.8%) lower total cholesterol and 12.7% (3.8%, 21.6%) lower LDL-C. In girls, higher urinary di-2-ethylhexyl phthalate metabolites (ΣDEHP) correlated with lower LDL-C (-7.9% [-15.4%, -0.4%]). Additional longitudinal research is needed to determine whether these associations persist beyond adolescence.

Effects of Di-(2-ethylhexyl) Phthalate on Lipid Metabolism by the JAK/STAT Pathway in Rats

The most widely used plasticizer, di-(2-ethylhexyl) phthalate (DEHP), is known to affect lipid metabolism and adipogenesis. We studied the effects of dietary DEHP exposure on metabolism in rats as well as the role of the JAK/STAT pathway in this process. Eighty rats were exposed to DEHP (0, 5, 50 and 500 mg/kg/d) through dietary intake for 4 weeks. We then collected blood samples, liver, and adipose tissues to detect modifications in the levels of serum lipids, leptin, adiponectin and insulin. JAK3, STAT5a and PPARγ expression were detected at both the gene and protein levels. The activation of JAK3 and STAT5a was also detected. The DEHP-exposed rats had increased body weight, serum lipid, insulin, and leptin levels. Moreover, the JAK3/STAT5a pathway was activated in the adipose tissue; however, this pathway was not activated in the liver. The mRNA of SREBP-1c in the liver was increased significantly among each of the groups, in contrast to the levels found in the mature SREBP-1c protein form. Furthermore, the expression of FABP4, Acox and FASn was decreased in the liver, but increased in adipose tissue. Thus, we conclude that exposure to DEHP reduces the hydrolysis of lipid and promotes triglyceride accumulation by oppositely regulating the activation state of JAK/STAT pathway in the liver and adipose tissue, resulting in the disorder of body lipid metabolism and obesity.

Effects of in utero exposure to polychlorinated biphenyls, methylmercury, and polyunsaturated fatty acids on birth size

The adverse effects of in utero exposure to polychlorinated biphenyls (PCBs) or methylmercury (MeHg), and the beneficial effects of nutrients from maternal fish intake might have opposing influences on fetal growth. In this study, we assessed the effects of in utero exposure to PCBs and MeHg on birth size in the Japanese population, which is known to have a high frequency of fish consumption. The concentrations of PCBs and polyunsaturated fatty acids in maternal blood, and the total mercury in hair (as a biomarker of MeHg exposure) were measured during pregnancy and at delivery. Maternal intakes of fish (subtypes: fatty and lean) and shellfishes were calculated from a food frequency questionnaire administered at delivery. Newborn anthropometric measurement data were obtained from birth records. The associations between chemical exposures and birth size were analyzed by using multiple regression analysis with adjustment for confounding factors among 367 mother-newborn pairs. The birth weight was 3073±37 g (mean±SD). The incidence of babies small for gestational age (SGA) by weight was 4.9%. The median concentrations of total PCBs and hair mercury were 108 ng/g lipid and 1.41 μg/g, respectively. There was no overall association between mercury concentrations and birth weight, birth length, chest circumference, and head circumference. We observed that the risk of SGA by weight decreased with increasing mercury concentration in regression analyses with adjustment for polyunsaturated fatty acids. Our results suggest that the beneficial effect of essential nutrition may mask the adverse effects of MeHg on birth size. The concentrations of PCBs had no association with birth size.

The Association of Prenatal Exposure to Perfluorinated Chemicals with Maternal Essential and Long-Chain Polyunsaturated Fatty Acids during Pregnancy and the Birth Weight of Their Offspring: The Hokkaido Study

BACKGROUND

Fatty acids (FAs) are essential for fetal growth. Exposure to perfluorinated chemicals (PFCs) may disrupt FA homeostasis, but there are no epidemiological data regarding associations of PFCs and FA concentrations.

OBJECTIVES

We estimated associations between perfluorooctane sulfonate (PFOS)/perfluorooctanoate (PFOA) concentrations and maternal levels of FAs and triglyceride (TG) and birth size of the offspring.

METHODS

We analyzed 306 mother-child pairs in this birth cohort between 2002 and 2005 in Japan. The prenatal PFOS and PFOA levels were measured in maternal serum samples by liquid chromatography-tandem mass spectrometry. Maternal blood levels of nine FAs and TG were measured by gas chromatography-mass spectrometry and TG E-Test Wako kits, respectively. Information on infants' birth size was obtained from participant medical records.

RESULTS

The median PFOS and PFOA levels were 5.6 and 1.4 ng/mL, respectively. In the fully adjusted model, including maternal age, parity, annual household income, blood sampling period, alcohol consumption, and smoking during pregnancy, PFOS but not PFOA had a negative association with the levels of palmitic, palmitoleic, oleic, linoleic, α-linolenic, and arachidonic acids (p < 0.005) and TG (p-value = 0.016). Female infants weighed 186.6 g less with mothers whose PFOS levels were in the fourth quartile compared with the first quartile (95% CI: -363.4, -9.8). We observed no significant association between maternal levels of PFOS and birth weight of male infants.

CONCLUSIONS

Our data suggest an inverse association between PFOS exposure and polyunsaturated FA levels in pregnant women. We also found a negative association between maternal PFOS levels and female birth weight.

Effects of exposure to Di(2-ethylhexyl)phthalate during fetal period on next generation

The concept of the Developmental Origins of Health and Disease (DOHaD) is bringing new insights into the origin of lifestyle diseases: unbalanced nutrition in utero and during infancy is associated with an increased risk of lifestyle diseases. In order to clarify this association, experimental and epidemiological studies have been conducted. Maternal exposure to di(2-ethylhexyl)phthalate (DEHP), an agonist of peroxisome proliferator-activated receptor α (PPARα), decreases the number of live fetuses and newborn pups, and their body weights, and it enhances fetal desorption in wild-type mice. Similarly, these DEHP were also observed in mice expressing human PPARα, but not in PPARα-null mice. These results suggest that the DEHP toxicity in offspring is caused dependently on PPARα. DEHP suppresses the increase in the levels of plasma triglyceride (TG)/fatty acids (FAs) only in wild-type pregnant mice, suggesting that the decreased lipid levels in utero may affect the fetus development, because TG/FAs are essential in the development of fetuses. Additionally, maternal DEHP exposure decreases estrogen and progesterone balances, which may also explain the effects on fetuses and pups mentioned above. Indeed, DEHP itself or metabolite(s) may induce the toxicity, because a difference in the metabolic route is observed between the wild-type and PPARα-null mice. Thus, we were unable to conclude the causal factor(s) for the DEHP-induced offspring toxicity, that is, whether it is a direct or an indirect effect of the chemical or metabolite(s) via the toxic effects on maternal mice; however, PPARα is indeed associated with in offspring toxicity.

Prenatal maternal blood triglyceride and fatty acid levels in relation to exposure to di(2-ethylhexyl)phthalate: a cross-sectional study

OBJECTIVES

The hypolipidemic effects of di(2-ethylhexyl)phthalate (DEHP) exposure in humans have not been investigated. And the influences of maternal prenatal DEHP exposure on birth outcomes are not well-known. We aimed to estimate prenatal DEHP exposure in maternal blood, and evaluate its relationships to maternal blood triglyceride (TG) and fatty acid (FA) levels and to birth outcomes.

METHODS

We studied 318 mother-newborn pairs residing in Sapporo, Japan. Blood was taken one time during pregnancy for each mother. Maternal and infant characteristics were obtained from medical records and questionnaire survey. We measured DEHP metabolite, mono(2-ethylhexyl) phthalate (MEHP), along with TG and 9 FAs using maternal blood, and analyzed associations of MEHP level with maternal blood TG/FA levels and infant birth dimensions.

RESULTS

Maternal blood TG and palmitoleic/oleic acid levels were higher, but stearic/docosahexaenoic acids and MEHP were lower during late pregnancy. Maternal blood MEHP levels inversely correlated with TG and palmitic/palmitoleic/oleic/linoleic/α-linolenic acids. After adjustment for confounders, we found that a tenfold increase in blood MEHP levels correlated with a decrease in TG of 25.1 mg/dl [95% confidence interval (CI) 4.8-45.3 mg/dl], and similar relations in palmitic (β = -581.8; 95 % CI -906.5, -257.0), oleic (β = -304.2; 95% CI -518.0, -90.5), linoleic (β = -348.6; 95% CI -510.6, -186.6), and α-linolenic (β = -6.3; 95% CI -9.5, -3.0) acids. However, we observed no correlations between maternal blood MEHP levels and infant birth weight, length, chest circumference, or head circumference.

CONCLUSIONS

Ambient DEHP exposure during pregnancy inversely correlated with maternal blood TG and 4 FA levels, but not birth outcomes.