Impacts of prenatal triclosan exposure on fetal reproductive hormones and its potential mechanism

Exposure to Synthetic Endocrine-Disrupting Chemicals in Relation to Maternal and Fetal Sex Steroid Hormones: A Scoping Review

PURPOSE OF REVIEW

Many synthetic endocrine-disrupting chemicals (EDCs) are ubiquitous in the environment and highly detected among pregnant people. These chemicals may disrupt maternal and/or fetal sex steroid hormones, which are critical to pregnancy maintenance and fetal development. Here, we review the epidemiological literature examining prenatal exposure to common synthetic EDCs in relation to maternal and fetal sex steroid hormones.

RECENT FINDINGS

We performed a literature search using PubMed, SCOPUS, and Embase, ultimately identifying 29 articles for full review. Phenols, parabens, and persistent organic pollutants generally showed inverse associations with androgens, estrogens, and progesterone. Phthalates and per-and polyfluoroalkyl substances tended to be inversely associated with progesterone, while evidence regarding androgens and estrogens was mixed. Inconsistent, but noteworthy, differences by fetal sex and timing of exposure/outcome were observed. Overall, the literature suggests EDCs may disrupt maternal and fetal sex steroid activity, though findings are mixed. Given the pervasive, high-volume production of these synthetic chemicals and the critical functions sex steroid hormones play during gestation, additional research is warranted.

Sex-Specific and Trimester-Specific Associations of Prenatal Exposure to Bisphenols, Parabens, and Triclosan with Neonatal Birth Size and Gestational Age

Bisphenols, parabens, and triclosan (TCS) are common endocrine disrupters used in various consumer products. These chemicals have been shown to cross the placental barrier and affect intrauterine development of fetuses. In this study, we quantified serum levels of six bisphenols, five parabens, and TCS in 483 pregnant women from southern China. Quantile-based g-computation showed that combined exposure to bisphenols, parabens, and TCS was significantly (p < 0.05) and negatively associated with birth weight (β = -39.9, 95% CI: -73.8, -6.1), birth length (β = -0.19, 95% CI: -0.34, -0.04), head circumference (β = -0.13, 95% CI: -0.24, -0.02), and thoracic circumference (β = -0.16, 95% CI: -0.29, -0.04). An inverse correlation was also identified between mixture exposure and gestational age (β = -0.12, 95% CI: -0.24, -0.01). Bisphenol A (BPA), bisphenol Z (BPZ), bisphenol AP (BPAP), propylparaben (PrP), and TCS served as the dominant contributors to the overall effect. In subgroup analyses, male newborns were more susceptible to mixture exposure than females, whereas the exposure-outcome link was prominent among pregnant women in the first and second trimesters. More evidence is warranted to elucidate the impacts of exposure to mixtures on birth outcomes, as well as the underlying mechanisms.

Toxicity evolution of triclosan during environmental transformation and human metabolism: Misgivings in the post-pandemic era

In the context of pandemic viruses and pathogenic bacteria, triclosan (TCS), as a typical antibacterial agent, is widely used around the world. However, the health risks from TCS increase with exposure, and it is widespread in environmental and human samples. Notably, environmental transformation and human metabolism could induce potentially undesirable risks to humans, rather than simple decontamination or detoxification. This review summarizes the environmental and human exposure to TCS covering from 2004 to 2023. Particularly, health impacts from the environmental and metabolic transformation of TCS are emphasized. Environmental transformations aimed at decontamination are recognized to form carcinogenic products such as dioxins, and ultraviolet light and excessive active chlorine can promote the formation of these dioxin congeners, potentially threatening environmental and human health. Although TCS can be rapidly metabolized for detoxification, these processes can induce the formation of lipophilic ether metabolic analogs via cytochrome P450 catalysis, causing possible adverse cross-talk reactions in human metabolic disorders. Accordingly, TCS may be more harmful in environmental transformation and human metabolism. In particular, TCS can stimulate the transmission of antibiotic resistance even at trace levels, threatening public health. Considering these accruing epidemiological and toxicological studies indicating the multiple adverse health outcomes of TCS, we call on environmental toxicologists to pay more attention to the toxicity evolution of TCS during environmental transformation and human metabolism.

Analysis of key circRNA events in the AOP framework of TCS acting on zebrafish based on the data-driven

Triclosan (TCS) is a broad-spectrum antibiotic widely used in various personal care products. Research has found that exposure to TCS can cause toxic effects on organisms including neurotoxicity, cardiotoxicity, disorders of lipid metabolism, and abnormal vascular development, and the corresponding toxic mechanisms are gradually delving into the level of abnormal expression of miRNA regulating gene expression. Although the downstream mechanism of TCS targeting miRNA abnormal expression to induce toxicity is gradually improving, its upstream mechanism is still in a fog. Starting from the abnormal expression data of circRNA in zebrafish larvae induced by TCS, this study conducted a hierarchical analysis of the expression levels of all circRNAs, differential circRNAs, and trend circRNAs, and identified 29 key circRNA events regulating miRNA abnormal expression. In combination with GO and KEGG, the effects of TCS exposure were analyzed from the function and signaling pathway of the corresponding circRNA host gene. Furthermore, based on existing literature evidence about the biological toxicity induced by TCS targeting miRNA as data support, a competing endogenous RNAs (ceRNA) network characterizing the regulatory relationship between circRNA and miRNA was constructed and optimized. Finally, a comprehensive Adverse Outcome Pathway (AOP) framework of multiple levels of events including circRNA, miRNA, mRNA, pathway, and toxicity endpoints was established to systematically elucidate the toxic mechanism of TCS. Moreover, the rationality of the AOP framework was verified from the expression level of miRNA and adverse outcomes such as neurotoxicity, cardiotoxicity, oxidative stress, and inflammatory response by knockdown of circRNA48. This paper not only provides the key circRNA events for exploring the upstream mechanism of miRNA regulating gene expression but also provides an AOP framework for comprehensively demonstrating the toxicity mechanism of TCS on zebrafish, which is a theoretical basis for subsequent hazard assessment and prevention and control of TCS.

Reproductive endocrine disruption effect and mechanism in male zebrafish after life cycle exposure to environmental relevant triclosan

Triclosan (TCS) is a wide-spectrum antibacterial agent that is found in various water environments. It has been reported to have estrogenic effects. However, the impact of TCS exposure on the reproductive system of zebrafish (Danio rerio) throughout their life cycle is not well understood. In this study, zebrafish fertilized eggs were exposed to 0, 10, and 50 μg/L TCS for 120 days. The study investigated the effects of TCS exposure on brain and testis coefficients, the expression of genes related to the hypothalamus-pituitary-gonadal (HPG) axis, hormone levels, vitellogenin (VTG) content, histopathological sections, and performed RNA sequencing of male zebrafish. The results revealed that life cycle TCS exposure had significant effects on zebrafish reproductive parameters. It increased the testis coefficient, while decreasing the brain coefficient. TCS exposure also led to a decrease in mature spermatozoa and altered the expression of genes related to the HPG axis. Furthermore, TCS disrupted the balance of sex hormone levels and increased VTG content of male zebrafish. Transcriptome sequencing analysis indicated that TCS affected reproductive endocrine related pathways, including PPAR signaling pathway, cell cycle, GnRH signaling pathway, steroid biosynthesis, cytokine-cytokine receptor interaction, and steroid hormone biosynthesis. Protein-protein interaction (PPI) network analysis confirmed the enrichment of hub genes in these pathways, including bub1bb, ccnb1, cdc20, cdk1, mcm2, mcm5, mcm6, plk1, and ttk in the brain, as well as fabp1b.1, fabp2, fabp6, ccr7, cxcl11.8, hsd11b2, and hsd3b1 in the testis. This study sheds light on the reproductive endocrine-disrupting mechanisms of life cycle exposure to TCS.

Associations of prenatal exposure to per- and polyfluoroalkyl substances and fetal sex hormones in the Guangxi Zhuang Birth Cohort Study: Greater effect of long-chain PFAS

Fetal sex hormone homeostasis disruption could lead to reproductive and developmental abnormalities. However, previous studies have reported inconsistent findings regarding the association of maternal per- and polyfluoroalkyl substances (PFAS) exposure with fetal sex hormone levels. A total of 277 mother-infant pairs from the Guangxi Zhuang Birth Cohort Study between 2015 and 2019 were selected. We quantified nine PFAS in maternal serum in early pregnancy, and detected three sex hormones, namely, estradiol (E2), progesterone (P4) and testosterone (TT), in cord blood. The generalized linear model (GLM) and Bayesian kernel machine regression (BKMR) model were used for single- and multiple-exposure analyses, respectively. In the GLM, there was no significant association between an individual PFAS and any hormone level or the E2/TT ratio, but a negative association between perfluorododecanoic acid (PFDoA) exposure and P4 levels in female infants was observed after stratification by sex. In the BKMR, a mixture of nine PFAS was positively associated with E2 levels and the E2/TT ratio, with the same main contributors, i.e., perfluoroundecanoic acid (PFUnA). And PFAS mixtures were not associated with P4 or TT levels. After stratification by infant sex, positive associations of PFAS mixtures with E2 levels and the E2/TT ratio were observed only in male infants, with the same main contributors, i.e., PFUnA. There was a positive association between PFAS mixtures and P4 levels in male infants, in which PFUnA was the main contributor; but a reverse association between PFAS mixtures and P4 levels in female infants, in which PFDoA was the main contributor. This study suggested that prenatal exposure to PFAS mixtures is associated with fetal sex hormones, and long-chain PFAS may play an important role in this association. Furthermore, sex differences in the association of maternal PFAS exposure with E2 and P4 levels need additional attention.

Adverse effects of triclosan exposure on health and potential molecular mechanisms

With the COVID-19 pandemic, the use of disinfectants has grown significantly around the world. Triclosan (TCS), namely 5-chloro-2-(2,4-dichlorophenoxy) phenol or 2,4,4'-trichloro-2'-hydroxydiphenyl ether, is a broad-spectrum, lipophilic, antibacterial agent that is extensively used in multifarious consumer products. Due to the widespread use and bioaccumulation, TCS is frequently detected in the environment and human biological samples. Accumulating evidence suggests that TCS is considered as a novel endocrine disruptor and may have potential unfavorable effects on human health, but studies on the toxic effect mediated by TCS exposure as well as its underlying mechanisms of action are relatively sparse. Therefore, in this review, we attempted to summarize the potential detrimental effects of TCS exposure on human reproductive health, liver function, intestinal homeostasis, kidney function, thyroid endocrine, and other tissue health, and further explore its mechanisms of action, thereby contributing to the better understanding of TCS characteristics and safety. Moreover, our work suggested the need to further investigate the biological effects of TCS exposure at the metabolic level in vivo.

Endocrine-Disrupting Chemicals and Hippocampal Development: The Role of Estrogen and Androgen Signaling

Hormones are important regulators of key processes during fetal brain development. Thus, the developing brain is vulnerable to the action of chemicals that can interfere with endocrine signals. Epidemiological studies have pointed toward sexually dimorphic associations between neurodevelopmental outcomes, such as cognitive abilities, in children and prenatal exposure to endocrine-disrupting chemicals (EDCs). This points toward disruption of sex steroid signaling in the development of neural structures underlying cognitive functions, such as the hippocampus, an essential mediator of learning and memory processes. Indeed, during development, the hippocampus is subjected to the organizational effects of estrogens and androgens, which influence hippocampal cell proliferation, differentiation, dendritic growth, and synaptogenesis in the hippocampal fields of Cornu Ammonis and the dentate gyrus. These early organizational effects correlate with a sexual dimorphism in spatial cognition and are subject to exogenous chemical perturbations. This review summarizes the current knowledge about the organizational effects of estrogens and androgens on the developing hippocampus and the evidence for hippocampal-dependent learning and memory perturbations induced by developmental exposure to EDCs. We conclude that, while it is clear that sex hormone signaling plays a significant role during hippocampal development, a complete picture at the molecular and cellular levels would be needed to establish causative links between the endocrine modes of action exerted by EDCs and the adverse outcomes these chemicals can induce at the organism level.

Prenatal triclosan exposure impairs mammalian lung branching morphogenesis through activating Bmp4 signaling

Triclosan (TCS) is a commonly used antibacterial agent present in personal care and household products. Recently, there have been increasing concerns about the association between children's health and TCS exposure during gestation, but the toxicological effects of TCS exposure on embryonic lung development remain undetermined. In this study, through using an ex vivo lung explant culture system, we found that prenatal exposure to TCS resulted in impaired lung branching morphogenesis and altered proximal-distal airway patterning. These TCS-induced dysplasias are accompanied by significantly reduced proliferation and increased apoptosis within the developing lung, as a consequence of activated Bmp4 signaling. Inhibition of Bmp4 signaling by Noggin partially rescues the lung branching morphogenesis and cellular defects in TCS-exposed lung explants. In addition, we provided in vivo evidence that administration of TCS during gestation leads to compromised branching formation and enlarged airspace in the lung of offspring. Thus, this study provides novel toxicological information on TCS and indicated a strong/possible association between TCS exposure during pregnancy and lung dysplasia in offspring.

Early life exposure to triclosan from antimicrobial daily necessities may increase the potential risk of autism spectrum disorder: A multicenter study in China

BACKGROUND

Autism spectrum disorders (ASD) are a group of complex neurodevelopmental disorders with unclear etiologies. Our recent work indicated that maternal exposure to triclosan (TCS) significantly increased the autistic-like behavior in rats, possibly through disrupting neuronal retinoic acid signaling. Although environmental endocrine disruptors (EEDs) have been associated with autism in humans, the relationship between TCS, one of the EEDs found in antibacterial daily necessities, and autism has received little attention.

OBJECTIVE

The aims of this multicenter study were to evaluate TCS concentrations in typically developing (TD) children and ASD children, and to determine the relationship between TCS levels and the core symptoms of ASD children.

METHODS

A total of 1345 children with ASD and 1183 TD children were enrolled from 13 cities in China. Ages ranged between 2 and 7 years. A questionnaire was used to investigate the maternal use of antibacterial daily necessities (UADN) during pregnancy. The core symptoms of ASD were evaluated using the Autism Behavior Checklist (ABC), Childhood Autism Rating Scale (CARS), Social Response Scale (SRS), and the Children Neuropsychological and Behavior Scale-Revision 2016 (CNBS-R2016). The TCS concentration was measured using LC-MS/MS.

RESULTS

Maternal UADN during pregnancy may be an unrecognized potential environmental risk factor for ASD (OR=1.267, P = 0.023). Maternal UADN during pregnancy strongly correlated with TCS levels in the offspring (Adjusted β = 0.277, P < 0.001). TCS concentration was higher in ASD children (P = 0.005), and positively correlated with ABC (Sensory subscales: P = 0.03; Social self-help subscales: P = 0.011) and SRS scale scores (Social awareness subscales: P = 0.045; Social communication subscales: P = 0.001; Autism behavior mannerisms subscales: P = 0.006; SRS total score: P = 0.003) in ASD children. This association was more pronounced in boys than in girls.

CONCLUSION

To our knowledge, this is the first case-control study to examine the correlation between TCS and ASD. Our results suggest that maternal UADN during pregnancy may be a potential risk of ASD in offspring. Further detection of TCS levels showed that maternal UADN during pregnancy may be associated with excessive TCS exposure. In addition, the level of TCS in children with ASD is higher than TD children. The higher levels of TCS in children with ASD may be significantly associated with more pronounced core symptoms, and this association was more significant in male children with ASD.

Glyphosate-induced mitochondrial reactive oxygen species overproduction activates parkin-dependent mitophagy to inhibit testosterone synthesis in mouse leydig cells

Glyphosate (GLY), one of the most extensively used herbicides in the world, has been shown to inhibit testosterone synthesis in male animals. Mitochondria are crucial organelles for testosterone synthesis and its dysfunction has been demonstrated to induce the inhibition of testosterone biosynthesis. However, whether low-dose GLY exposure targets mitochondria to inhibit testosterone synthesis and its underlying mechanism remains unclear. Here, an in vitro model of 10 μM GLY-exposed mouse Leydig (TM3) cells was established to elucidate this issue. Data firstly showed that mitochondrial malfunction, mainly manifested by ultrastructure damage, disturbance of mitochondrial dynamics and mitochondrial reactive oxygen species (mtROS) overproduction, was responsible for GLY-decreased protein levels of steroidogenic enzymes, which leads to the inhibition of testosterone synthesis. Enhancement of autophagic flux and activation of mitophagy were shown in GLY-treated TM3 cells, and further studies have revealed that GLY-activated mitophagy is parkin-dependent. Notably, GLY-inhibited testosterone production was significantly improved by parkin knockdown. Finally, data showed that treatment with mitochondria-targeted antioxidant Mito-TEMPO (M-T) markedly reversed GLY-induced mitochondrial network fragmentation, activation of parkin-dependent mitophagy and consultant testosterone reduction. Overall, these findings demonstrate that GLY induces mtROS overproduction to activate parkin-dependent mitophagy, which contributes to the inhibition of testosterone synthesis. This study provides a potential mechanistic explanation for how GLY inhibits testosterone synthesis in mouse Leydig cells.

Associations between repeated measurements of childhood triclosan exposure and physical growth at 7 years

BACKGROUND

Epidemiological studies suggested that triclosan (TCS) exposure was ubiquitous among children and could affect their physical growth. However, most studies relied on TCS exposure at single time point, and the impacts of multiple time points TCS exposure were unclear.

OBJECTIVES

To estimate the associations between repeated TCS measurements in childhood (at ages 1, 2, 5, and 7 years) and physical growth at 7 years.

METHODS

This study included 206 children from Laizhou Wan Birth Cohort (LWBC), China. Urinary TCS concentrations were detected at age of 1, 2, 5, and 7 years, and physical growth including height, weight, waist circumference, and fat percentage was measured at 7 years. Multiple informant models were applied to examine the relationships of repeated TCS measurements in childhood with physical growth, and stratified analysis by gender was performed.

RESULTS

The detection rates of TCS at age of 1, 2, 5, and 7 years were above 60%, with median declining from 0.89 to 0.33 μg/g creatinine. We found TCS at 5 years was positively associated with waist-to-height ratio, and TCS at 7 years was positively associated with physical growth, including weight z-score, BMI z-score, waist circumference, waist-to-height ratio, and fat percentage. Moreover, the above associations for weight z-score, BMI z-score, and fat percentage significantly varied by the period of exposure (pint ˂ 0.05). After stratified by gender, positive associations were only found among boys.

CONCLUSIONS

In our study, TCS levels decreased as children's age increased. TCS exposures at age of 5 and 7 years were positively associated with physical growth at 7 years, and these associations were only significant in boys. Given the relatively small sample size, our findings should be interpreted with caution until confirmed by further investigation.

Effect of Maternal Triclosan Exposure on Neonatal Thyroid-Stimulating Hormone Levels: A Cross-Sectional Study

Objective

This study is aimed at assessing the relationship between maternal urinary triclosan (uTCS) exposure and the thyroid-stimulating hormone (TSH) level of infant cord blood.

Methods

This cross-sectional study was carried out in 2019-2020 in Isfahan, Iran, and 99 pregnant women participated in the study. Urine samples were collected after the 28th week of pregnancy, and the concentration of TCS was measured using GC/MS. The cord blood levels of TSH (CBL-TSH) were measured. The association between uTCS and CBL-TSH was examined based on the general linear model.

Results

TCS was detected (≥0.01 ng/mL) in 100% of the urine samples, with the interquartile range (25%-75%) of uTCS levels 0.6-6.23 μg/g Cr. uTCS was not associated with CBL-TSH after adjustment for covariates. A significant relationship was observed between CBL-TSH of neonates born to mothers who had given birth only once compared to mothers who had given birth twice or more times.

Conclusions

Maternal exposure to TCS did not affect the infant CBL-TSH. However, the high concentrations of TCS in maternal urinary samples indicate the necessity of more precise regulations to decrease the use of this chemical in the industry and increase public awareness about using TCS-free compounds.

Triclosan: A Small Molecule with Controversial Roles

Triclosan (TCS), a broad-spectrum antimicrobial agent, has been widely used in personal care products, medical products, plastic cutting boards, and food storage containers. Colgate Total® toothpaste, containing 10 mM TCS, is effective in controlling biofilm formation and maintaining gingival health. Given its broad usage, TCS is present ubiquitously in the environment. Given its strong lipophilicity and accumulation ability in organisms, it is potentially harmful to biohealth. Several reports suggest the toxicity of this compound, which is inserted in the class of endocrine disrupting chemicals (EDCs). In September 2016, TCS was banned by the U.S. Food and Drug Administration (FDA) and the European Union in soap products. Despite these problems, its application in personal care products within certain limits is still allowed. Today, it is still unclear whether TCS is truly toxic to mammals and the adverse effects of continuous, long-term, and low concentration exposure remain unknown. Indeed, some recent reports suggest the use of TCS as a repositioned drug for cancer treatment and cutaneous leishmaniasis. In this scenario it is necessary to investigate the advantages and disadvantages of TCS, to understand whether its use is advisable or not. This review intends to highlight the pros and cons that are associated with the use of TCS in humans.

Associations of paternal and maternal per- and polyfluoroalkyl substances exposure with cord serum reproductive hormones, placental steroidogenic enzyme and birth weight

BACKGROUND

Maternal per- and polyfluoroalkyl substances (PFAS) exposure has been associated with placental function and fetal growth measures. However, few studies have simultaneously investigated paternal and maternal exposure effects.

OBJECTIVES

We evaluated the associations of paternal or maternal PFAS levels with placental function and fetal growth measures.

METHODS

We studied six PFAS measured in matched parental serums collected within 3 days before delivery in a birth cohort from LaiZhouWan, China. Outcomes evaluated include cord serum estradiol (n = 351), testosterone (n = 349), placental P450aromatase (n = 125), and birth weight (n = 369). Multiple linear regression was applied to estimate the associations for these outcomes according to paternal or maternal PFAS level after adjusting for socio-demographic confounders. Co-adjustment analysis of both paternal and maternal PFAS in the same model was performed.

RESULTS

Maternal and paternal PFAS levels were correlated (Spearman's r = 0.23-0.45). Maternal PFAS were associated with increased estradiol (e.g.

, PFOA

β = 0.03, 95%CI: 0.00, 0.07), testosterone (e.g.

, PFUA

β = 0.14, 95%CI: 0.00, 0.27), and P450aromatase (e.g.

, PFOA

β = 0.13, 95%CI: 0.04, 0.22). Maternal PFAS were also associated with a lower mean of birth weight but the estimated 95% CI included the null. Paternal PFAS were not associated with any of the outcomes evaluated.

CONCLUSIONS

Several maternal PFAS were associated with fetal steroid hormones and placental enzymes. Despite a correlation of PFAS level within the couples, no association was found for paternal PFAS exposure on these outcomes. The findings suggest the intrauterine PFAS exposure effect on fetal endocrine hormones and growth is unlikely to be confounded by exposure sources or familial factors shared within the couples.

Praegnatio Perturbatio-Impact of Endocrine-Disrupting Chemicals

The burden of adverse pregnancy outcomes such as preterm birth and low birth weight is considerable across the world. Several risk factors for adverse pregnancy outcomes have been identified. One risk factor for adverse pregnancy outcomes receiving considerable attention in recent years is gestational exposure to endocrine-disrupting chemicals (EDCs). Humans are exposed to a multitude of environmental chemicals with known endocrine-disrupting properties, and evidence suggests exposure to these EDCs have the potential to disrupt the maternal-fetal environment culminating in adverse pregnancy and birth outcomes. This review addresses the impact of maternal and fetal exposure to environmental EDCs of natural and man-made chemicals in disrupting the maternal-fetal milieu in human leading to adverse pregnancy and birth outcomes-a risk factor for adult-onset noncommunicable diseases, the role lifestyle and environmental factors play in mitigating or amplifying the effects of EDCs, the underlying mechanisms and mediators involved, and the research directions on which to focus future investigations to help alleviate the adverse effects of EDC exposure.

Associations among urinary triclosan and bisphenol A concentrations and serum sex steroid hormone measures in the Canadian and U.S. Populations

Exposure to triclosan, an antimicrobial agent, and bisphenol A (BPA), the monomer of polycarbonate plastics, is widespread. Endocrine-disrupting impacts of these chemicals have been demonstrated in in vitro studies, rodent toxicology studies, and some human observational studies. Here we compared urinary concentrations of triclosan and BPA in the Canadian and U.S. populations using nationally-representative data from the 2012-2015 Canadian Health Measures Survey (CHMS) and the 2013-2016 National Health and Nutrition Examination Survey (NHANES). We then examined the cross-sectional associations of urinary triclosan or BPA with serum sex steroid hormones, including estradiol (E2), progesterone (P4), and testosterone (T), using multivariable regression. We observed differences in creatinine-standardized chemical concentrations between countries; urinary triclosan was higher in Canadian females aged 12-19 years, while BPA was higher in U.S. females aged 20-49 years. We also found significant associations among urinary chemicals and serum E2 and T, but not P4. Increasing triclosan was associated with higher levels of E2 in 6-11-year-old girls, but with lower levels of E2 and T in adolescent boys aged 12-19 years. Increasing BPA was associated with lower levels of E2 in 6-11-year-old boys and in adolescents aged 12-19 years of either sex. We observed a U-shaped association between urinary triclosan and E2 in male adults aged 50-79 years; no associations between BPA and hormones were detected in adults. These results, in accordance with the in vitro and animal literature, suggest that triclosan and BPA exposures may be cross-sectionally associated with altered reproductive hormone levels, especially in children and adolescents. Further research and prospective studies are necessary to elucidate country-specific differences in chemical exposures and the potential public health significance of these findings.

Exposure of Slovenian children and adolescents to bisphenols, parabens and triclosan: Urinary levels, exposure patterns, determinants of exposure and susceptibility

Chemicals such as bisphenols, parabens and triclosan are endocrine disrupting chemicals. They are used in a wide variety of consumer products, making human exposure to those chemicals widespread. In the present study, levels of three bisphenols (bisphenol A, F and S), 7 parabens (methyl-, ethyl-, isopropyl-, propyl-, isobutyl-, butyl-, benzyl paraben) and triclosan were measured in first morning void from 246 Slovenian children and adolescents, aged 6-9 and 11-15 years and living in a rural region of Slovenia. Median levels of specific-gravity corrected levels for bisphenol A, bisphenol F, methyl paraben and ethyl paraben were 1.9, 0.085, 5.4 and 2.5 µg/L for children and 1.6, 0.11, 7.2 and 6.0 µg/L for adolescents, respectively. Median levels for all other endocrine disrupting chemicals were < LOQ. The levels are comparable with the levels reported in studies across the world. Exposure was age, sex, and location specific. Higher levels of bisphenol F and ethyl paraben were found in the samples of adolescents, while higher levels of methyl paraben were found in samples from girls. Furthermore, individuals living in one of the sampling locations, Goričko, were exposed to higher levels of bisphenol F and ethyl paraben than those in the remaining two sampling locations. Information about participants' dietary habits, use of food packaging and personal care products was obtained through questionnaires, and used to investigate associations between urinary levels of the biomarkers and potential exposure sources. High fat foods were associated with bisphenol A exposure, and cosmetics items such as lipstick and perfume with methyl paraben exposure. Significant correlation between methyl- and propyl paraben was observed in children's samples, suggesting similar exposure sources, while other compounds were not largely correlated, indicating independent sources. Furthermore, association between a single nucleotide polymorphism (SNP) in UGT2B15 gene and urinary levels of methyl and ethyl paraben was observed, showing the role of UGT2B15 isoform in methyl and ethyl paraben metabolism as well as indicating the SNP rs1902023 as a potential biomarker of susceptibility to adverse effects caused by the exposure. The present study reports exposure of children and adolescents in Slovenia to a wide range of different endocrine disrupting chemicals for the first time, connecting it to exposure patterns and exposure sources. The study is to the authors' knowledge the first that investigates direct connection between levels of urinary endocrine disrupting chemical biomarkers and genetic polymorphism in UGT2B15.

Prenatal exposure to multiple phenolic compounds, fetal reproductive hormones, and the second to fourth digit ratio of children aged 10 years in a prospective birth cohort

Select phenols are known to possess hormone-disrupting properties, but no previous study has addressed the potential effects of prenatal exposure to phenol mixtures on fetal reproductive hormones and children's second to fourth digit (2D: 4D) ratio, a marker for in utero testosterone (T) exposure. We aimed to explore interrelations of prenatal phenol exposures individually and in mixtures, cord serum reproductive hormones, and 2D: 4D ratio of children aged 10 years. Urinary 11 phenol concentrations were determined from 392 pregnant women participating in a longitudinal birth cohort. We estimated associations of prenatal phenol exposures individually and in mixtures with cord reproductive hormones and children's 2D:4D ratio using three statistical approaches, including generalized linear models (GLMs), elastic net regression (ENR) models and Bayesian kernel machine regression (BKMR) models. In female newborns, the three models showed that maternal triclosan (TCS) concentrations were significantly negatively associated with cord serum T levels [regression coefficient (β) = -0.076, 95% confidence interval (CI): 0.138, -0.013; p = 0.018]. Additionally, maternal urinary bisphenol A (BPA) levels were related to decreases in 2D:4D ratio of the left hand in girls by GLMs (β = -0.003, 95% CI: 0.007, -0.001; p = 0.024) and ENR models, but not BKMR models. We provided evidence that prenatal TCS exposure predicted lower cord serum T levels, and maternal BPA exposure was related to decreased 2D:4D ratio of the left hand in females.

Triclosan and triclocarbon in maternal-fetal serum, urine, and amniotic fluid samples and their implication for prenatal exposure

Triclosan (TCS) and Triclocarbon (TCC) are chlorinated synthetic antimicrobial agents formaternal urinelated in quantities of consumer products. However, the biomonitoring of direct exposure reflection for fetuses are rare. In this study, we determine the concentrations of TCS and TCC in paired maternal serum, cord serum, maternal urine, and amniotic fluid samples collected from a cohort of 95 expecting mother-fetal pairs in Southern China. TCS and TCC are detected widely (detection rates: >76.9%) in maternal serum, cord serum, maternal urine, and amniotic fluid samples. TCS is found to be the predominant antimicrobial agent with median concentrations in maternal serum (1.5 ng/mL) and cord serum (1.8 ng/mL) that are one order of magnitude higher than those of tcc in maternal serum (0.085 ng/mL) and cord serum (0.052 ng/mL), respectively. Cord serum concentrations of tcs and tcc correlated well with the concentrations in maternal serum, which reflect the mothers' contribution to fetal exposure. The higher median ratio of cord serum/maternal serum_TCS (0.95) compared to that of cord serum/maternal serum_TCC (0.53) indicates high placental transmission ability of TCS. Moreover, the facility to penetrate the placental barrier and hard to depurate characteristics lead to the long residence of TCS in the fetal environment, causing great concern over the prenatal exposure risks during the critical window of fetal development. This study provides a novel contribution by increasing existing knowledge on the exposure assessment of TCS and TCC during pregnancy through the exploration of matched maternal-fetal samples.

Association between Prenatal Exposure to PFAS and Fetal Sex Hormones: Are the Short-Chain PFAS Safer?

Epidemiologic evidence regarding the effects of in utero exposure to per- and polyfluoroalkyl substances (PFAS), particularly short-chain PFAS, on fetal reproductive hormones is limited and inconsistent. This study aimed to assess the relationship between maternal PFAS exposure and fetal reproductive hormones. A total of 752 mother-infant pairs who were recruited in the Shanghai Birth Cohort Study between 2013 and 2016 were selected. We quantified 10 PFAS, including two short-chain PFAS congeners (perfluorobutanesulfonate, PFBS and perfluoroheptanoic acid, PFHpA), in maternal blood plasma in early pregnancy. Dehydroepiandrosterone sulfate (DHEA-S), sex hormone-binding globulin (SHBG), luteinizing hormone (LH), follicle-stimulating hormone (FSH) and total testosterone (TT) were measured in the umbilical cord blood using chemiluminescence kits. Free androgen index (FAI) was calculated by TT divided by SHBG. Multiple linear regression found that one ln-unit increase in maternal PFBS was associated with decreases in FSH (-0.159; 95% CI: -0.290, -0.029), LH (-0.113; 95% CI: -0.221, -0.004), and FAI (-0.009; 95% CI: -0.017, -0.001). In addition, PFHpA showed negative associations with LH (-0.154; 95% CI: -0.297, -0.011) and FAI (-0.008; 95% CI: -0.014, -0.002). When PFAS were analyzed in quartiles, significant negative associations were observed between PFBS and FSH, and between PFHpA and FAI. Overall, prenatal exposure to PFBS and PFHpA was associated with the disturbance of fetal gonadotropins as well as free androgen level in this prospective cohort, suggesting that the reproductive toxicity of short-chain PFAS may not be neglected.

Perinatal Exposure to Triclosan Results in Abnormal Brain Development and Behavior in Mice

Triclosan (TCS) is one of the most common endocrine-disrupting chemicals (EDCs) present in household and personal wash products. Recently, concerns have been raised about the association between abnormal behavior in children and exposure to EDC during gestation. We hypothesized that exposure to TCS during gestation could affect brain development. Cortical neurons of mice were exposed in vitro to TCS. In addition, we examined in vivo whether maternal TCS administration can affect neurobehavioral development in the offspring generation. We determined that TCS can impair dendrite and axon growth by reducing average length and numbers of axons and dendrites. Additionally, TCS inhibited the proliferation of and promoted apoptosis in neuronal progenitor cells. Detailed behavioral analyses showed impaired acquisition of spatial learning and reference memory in offspring derived from dams exposed to TCS. The TCS-treated groups also showed cognition dysfunction and impairments in sociability and social novelty preference. Furthermore, TCS-treated groups exhibited increased anxiety-like behavior, but there was no significant change in depression-like behaviors. In addition, TCS-treated groups exhibited deficits in nesting behavior. Taken together, our results indicate that perinatal exposure to TCS induces neurodevelopment disorder, resulting in abnormal social behaviors, cognitive impairment, and deficits in spatial learning and memory in offspring.

Prenatal exposure to mixture of heavy metals, pesticides and phenols and IQ in children at 7 years of age: The SMBCS study

OBJECTIVE

Prenatal exposure to heavy metals, pesticides and phenols has been suggested to interfere with neurodevelopment, but the neurotoxicity of their mixtures is still unclear. We aimed to elucidate the associations of maternal urinary concentrations of selected chemical mixtures with intelligence quotient (IQ) in children.

METHODS

Maternal urinary concentrations of selected heavy metals, pesticide metabolites, and phenols were quantified in pregnant women who participated in the Sheyang Mini Birth Cohort Study (SMBCS) from June 2009 to January 2010. At age 7 years, child's IQ score was assessed using the Chinese version of Wechsler Intelligence Scale for Children (C-WISC) by trained pediatricians. Generalized linear regression models (GLM), Bayesian kernel machine regression (BKMR) models and elastic net regression (ENR) models were used to assess the associations of urinary concentrations individual chemicals and their mixtures with IQ scores of the 7-year-old children.

RESULTS

Of 326 mother-child pairs, single-chemical models indicated that prenatal urinary concentrations of lead (Pb) and bisphenol A (BPA) were significantly negatively associated with full intelligence quotient (FIQ) among children aged 7 years [β = -2.31, 95% confidence interval (CI): -4.13, -0.48; p = 0.013, sex interaction p-value = 0.076; β = -1.18, 95% CI: -2.21, -0.15; p = 0.025; sex interaction p-value = 0.296, for Pb and BPA, respectively]. Stratified analysis by sex indicated that the associations were only statistically significant in boys. In multi-chemical BKMR and ENR models, statistically significant inverse association was found between prenatal urinary Pb level and boy's FIQ scores at 7 years. Furthermore, BKMR analysis indicated that the overall mixture was associated with decreases in boy's IQ when all the chemicals' concentrations were at their 75th percentiles or higher, compared to at their 50th percentiles. ENR models revealed that maternal urinary Pb levels were statistically significantly associated with lower FIQ scores (β = -2.20, 95% CI: -4.20, -0.20; p = 0.031).

CONCLUSIONS

Prenatal exposure to selected chemical mixtures may affect intellectual performance at 7 years of age, particularly in boys. Pb and BPA were suspected as primary chemicals associated with child neurodevelopment.

Association of blood metal exposure with testosterone and hemoglobin: A cross-sectional study in Hangzhou Birth Cohort Study

BACKGROUND

Few epidemiological studies have investigated associations of exposure to multiple metals with testosterone homeostasis and erythropoiesis, especially for the pregnant women.

METHODS

Among all the 1644 participants enrolled in Hangzhou Birth Cohort Study (HBCS) at baseline, a total of 918 pregnant women with complete data of interest were analyzed. The whole blood metals levels were examined by inductively coupled plasma mass spectrometry (ICP-MS), and serum testosterone level was evaluated by chemiluminescent microparticle immunoassay (CMIA), and erythropoietic parameters values were extracted from medical record. Multivariable linear regression models were applied to estimate the relationships between metals levels and testosterone level, and between metals levels and erythropoietic parameters, and potential confounders were adjusted.

RESULTS

Single metal model analysis revealed a significant association of blood As, Mn and Pb level with serum testosterone level. After controlling for multiple testing, the dose-response trend with statistical significance (FDR-adjusted p trend <0.05) was observed across tertiles of Pb with testosterone. This association, when by stratified by gender, remained in pregnant women with a male fetus but did not reach significant in those with a female fetus. Furthermore, blood Pb level was positively associated with red blood cell counts, hemoglobin level and hematocrit. Serum testosterone level was positively associated with red blood cell counts, hemoglobin level and hematocrit. Mediation analyses indicated that testosterone might act as a mediator in the association between Pb exposure and erythropoietic parameters.

CONCLUSIONS

Serum testosterone level and hemoglobin level was positively related to blood Pb level among Chinese pregnant women, and testosterone might mediate the effect of Pb exposure on hemoglobin. Additional prospective studies are warranted to confirm the causality.

PI3K/Akt/FoxO pathway mediates glycolytic metabolism in HepG2 cells exposed to triclosan (TCS)

Triclosan (TCS) has been widely used as an antibacterial agent for the last several decades in personal care products. The toxicological effect of TCS has attracted more and more attention of researchers. The purpose of this study is to evaluate the cytotoxic effects of TCS in HepG2 cells and to elucidate the molecular mechanism focusing on regulation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/forkhead box O (FoxO) pathway in the glycolytic metabolism. In this study, we evaluated the adverse effect of TCS exposure on cell viability, reactive oxygen species (ROS) generation, superoxide dismutase (SOD) activity and mitochondrial membrane potential (MMP). In addition, the glycolysis process in HepG2 cells exposed to TCS was examined in terms of glucose consumption, lactate production and ATP generation. Furthermore, Affymetrix Human U133 plus 2.0 gene chips and gene function enrichment analysis were conducted to screen differential expression genes (DEGs) and potential signaling pathway. Expressions of the glycolysis-related proteins were measured and quantified with Western Blotting. The results showed that TCS could suppress the cell viability, induce oxidative stress, and cause mitochondrial damage. In addition, TCS exposure promoted the glycolysis process, as manifested by accelerated conversion of glucose to lactate and increased energy release. Western Blotting results confirmed that the expression levels of glycolysis related proteins were significantly elevated. The PI3K/Akt/FoxO pathway was identified to play a pivot role in TCS-induced glycolysis, which was further confirmed by inhibitor tests using specific inhibitors LY294002 and MK2206. In general, TCS can induce oxidative stress, cause oxidative damages and promote glycolysis in HepG2 cells, which was mediated by the PI3K/Akt/FoxO pathway.

Lipid metabolism disorders contribute to hepatotoxicity of triclosan in mice

Previous in vivo exposure studies focused mainly on nuclear receptors involved in hepatotoxicity of triclosan (TCS). As liver plays a vital role in metabolic processes, dysregulations in lipid metabolism have been identified as potential drivers of pathogenesis. Investigation of changes in lipid metabolism might widen our understanding of toxicological effects as well as the underlying mechanism occurring in the liver. In this study, we comprehensively assessed the effect of TCS exposure on hepatic lipid metabolism in mice. Our results showed that TCS induced significant changes in hepatic free fatty acid pool by upregulation of fatty acid uptake and de novo fatty acid synthesis. Besides, hepatic levels of lipids, including acyl carnitine (AcCa), ceramide (Cer), triacylglycerols (TG), phosphatidylcholine (PC), lysophosphatidylcholine (LPC), phosphatidylethanolamine (PE) were also increased, together with upreguation of genes associated to TG synthesis, fatty acid oxidation and inflammation in TCS exposure group. These changes in lipid homeostasis could contribute to membrane instability, lipid accumulation, oxidative stress and inflammation. Our results suggested that TCS exposure could induce hepatic lipid metabolism disorders in mice, which would further contribute to the liver damage effects of TCS.

Removal of triclosan during wastewater treatment process and sewage sludge composting-A case study in the middle reaches of the Yellow River

Triclosan (TCS) is widely used as an antibacterial disinfectant in personal care products, especially in rapidly-urbanizing countries, such as China. Almost all TCS enters wastewater treatment plants (WWTPs), but the fate of the TCS in the WWTPs is unclear. TCS may be present in sewage sludge or in effluent, and the discharge of TCS into an ecosystem can pose environmental risks. In the present study, influent, effluent, and sewage sludge were collected from four typical urban WWTPs, and the fate of TCS in the plants was investigated. The study was conducted in Zhengzhou, a city in the middle reaches of the Yellow River in China. The sewage sludge was used for aerobic composting to study the influences of different ventilation treatments on the biodegradation effects of TCS and the changes in the microbial community during the composting process. The results showed that the mean concentration of TCS in the influent of the four typical WWTPs was 397.1 ng/L. The mean level of TCS in the effluent was 8.0 ng/L. The mean concentration of TCS in the sewage sludge was 814.4 ng/g. For the four WWTPs, the percentages of TCS removal were 97.6% (Nansanhuan), 97.6% (Xinzheng), 98.8% (Wulongkou), and 97.9% (Chenyu), respectively. The sewage sludge enrichment rates for TCS ranged between 36.4% and 49%. Therefore, there is a need to focus on the environmental risks from sewage sludge. During aerobic composting, the TCS was effectively degraded under three ventilation strategies. Thus, improved ventilation could enhance the degradation rate of TCS. Moreover, TCS degradation occurred in the mesophilic period and in the early stage of the thermophilic phase period. Finally, the degradation rates of TCS in sewage sludge samples composted with low-, medium-, and high-ventilation treatments were 48.1%, 59.0%, and 59.5%, respectively. Thus, high ventilation could provide enough oxygen for the pile and enhanced microorganism activity, benefiting the degradation of TCS. In addition, the microbial communities change during the composting process, and a diversity index of the changes can help explain the composting process.

Triclosan: antimicrobial mechanisms, antibiotics interactions, clinical applications, and human health

The large-scale applications of Triclosan in industrial and household products have created many health and environmental concerns. Despite the fears of its drug-resistance and other issues, Triclosan is still an effective drug against many infectious organisms. Knowing the cross-interactions of Triclosan with different antibiotics, bacteria, and humans can provide much-needed information for the risk assessment of this drug. We review the current understanding of the antimicrobial mechanisms of Triclosan, how microbes become resistant to Triclosan, and the synergistic and antagonistic effects of Triclosan with different antibiotics. Current literature on the clinical applications of Triclosan and its effect on fetus/child development are also summarized.

The Impact of Early-Life Exposure to Antimicrobials on Asthma and Eczema Risk in Children

PURPOSE OF REVIEW

We examined recent research on associations of prenatal and early-childhood exposure to the antimicrobial compounds, triclosan, and parabens, with the risk of asthma and eczema in children. We will discuss potential biological mechanisms of this association and highlight strengths and limitations of the study design and exposure assessment of current findings.

RECENT FINDINGS

Results of available toxicological and epidemiologic studies indicate a potential link of triclosan and paraben exposures with asthma and eczema in children, as well as changes in microbiome diversity and immune dysfunction, which could possibly mediate an association with the health outcomes. A small number of studies suggest that triclosan and paraben exposures could be related to the risk of asthma and eczema in children. Although current findings are far from conclusive, there is emerging evidence that changes in microbiome diversity and immune function from antimicrobial exposure may mediate these relations.

Triclosan induces PC12 cells injury is accompanied by inhibition of AKT/mTOR and activation of p38 pathway

Triclosan (TCS) has been widely used as a disinfectant and antiseptic in multiple consumer and healthcare products due to its clinical effectiveness against various bacteria, fungi and protozoa. Recently, several studies have reported the adverse effects of TCS on various nerve cells, arousing concerns about its potential neurotoxicity. The present study aimed to investigate the neurotoxicity of TCS in rat pheochromocytoma PC12 cells. After differentiation, the stabilized PC12 cells were treated with 1, 10, 50 μM TCS for 12 h. At the end of the treatment, the generation of reactive oxygen species (ROS), protein expression of apoptotic-related genes, AMPK-AKT/mTOR, as well as p38 in PC12 cells were determined. The concentrations were chosen based on the results of cell viability and lactic dehydrogenase (LDH) assays in response to TCS treatment (ranging from 0.001 to 100 μM) for varied time periods. The results showed that TCS is cytotoxic to PC12 cells, causing decreased cell viability accompanied by increased LDH release. TCS treatment at 10 and 50 μM for 12 h increased the mRNA and protein expression of the pro-apoptotic gene Bax, while Bcl-2 levels remained unchanged. Moreover, an increase in the generation of reactive oxygen species (ROS) was found in TCS-treated PC12 cells at the concentrations of 1 and 10 μM. Pretreatment with 100 μM N-acetyl cysteine (NAC- ROS scavenger) for 1 h normalized the ROS generations in TCS-treated PC12 cells. Additionally, the suppression of the phosphorylation of Akt and mTOR was observed in TCS-treated PC12 cells at 10 and 50 μM for 12 h, concomitant with the activation of p38 MAPK pathway at 50 μM TCS. However, there were no effects of TCS on the phosphorylation of AMPK in these cells. Taken together, these results suggest that TCS may cause adverse effects and oxidative stress in PC12 cells accompanied by inhibition of Akt/mTOR and activation of p38.

Cord blood Per- and polyfluoroalkyl substances, placental steroidogenic enzyme, and cord blood reproductive hormone

BACKGROUND

Per- and polyfluoroalkyl substances (PFASs) are widely used in China, but little is known about the association between prenatal PFASs exposure and fetal reproductive development as well as its potential mechanism.

OBJECTIVE

We investigated the effects of cord blood PFASs on fetal reproductive hormones and its potential mechanism in relation to steroidogenic enzymes.

METHODS

Ten selected PFASs (n = 351) including PFOS, PFOA, PFBS, PFDA, PFDoA, PFHpA, PFHxS, PFNA, PFOSA, and PFUA, and two reproductive hormones estradiol (E2) (n = 351) and testosterone (T) (n = 349) were measured in 351 cord blood serum samples from a Chinese birth cohort between 2010 and 2013. Three steroidogenic enzymes including P450arom (n = 125), 3β-HSD1 (n = 123), and 17β-HSD1 (n = 116) were measured in 125 placental tissue samples. Linear regression tested the associations between cord blood PFASs and reproductive hormones in cord blood. Mediation analysis assessed the role of placental steroidogenic enzymes between cord blood PFASs and reproductive hormones.

RESULTS

The positive associations between PFOA, PFHxS and E2 levels, PFOS, PFUA, PFNA and T levels, and PFOS, PFUA and T/E2 ratio were significant. PFUA, PFNA, PFDA, PFHxS, and ∑PFASs were associated with higher P450arom levels. PFHxS was also associated with increased 3β-HSD1 and 17β-HSD1 levels. These associations were more pronounced in females than males when stratified by gender. Furthermore, 17β-HSD1 demonstrated mediating effects in the positive association between cord blood PFHxS and E2 levels in females.

CONCLUSION

Our findings suggested the potential impacts of cord blood PFASs on fetal reproductive hormones, in which steroidogenic enzymes may play important roles. These associations were more pronounced in females than males.

Early-life triclosan exposure and parent-reported behavior problems in 8-year-old children

BACKGROUND

Triclosan exposure may decrease circulating thyroxine levels or cause neuron apoptosis, which in turn may adversely affect neurodevelopment. However, few studies have examined the association of early life triclosan exposure with child behavior.

OBJECTIVE

To quantify the association between early-life triclosan exposure and child behavior at age 8-years in 202 mother-child pairs from the HOME study (Cincinnati, OH; enrolled: 2003-2006).

METHODS

We quantified urinary triclosan concentrations up to 3 times in mothers (16-weeks, 26-weeks, and delivery) and up to 6 times in children (1, 2, 3, 4, 5, and 8 years). Parents rated children's problem behaviors at age 8-years using the Behavioral Assessment System for Children-2 (BASC-2). Adjusting for covariates and accounting for exposure measurement error, we estimated changes in behavior problem scores per 10-fold increase in mean gestational and childhood triclosan concentrations. In addition, we estimated sex-specific associations.

RESULTS

Child sex modified the association of gestational and childhood triclosan with several BASC-2 scales (sex × triclosan p-values < 0.2). In boys, increasing gestational triclosan was associated with higher behavioral symptom index (β: 4.5; 95% CI: 1.0, 8.1), externalizing problems (β: 5.0; 95% CI: 1.2, 9.0), attention problem (β: 6.6; 95% CI: 2.4, 11), hyperactivity (β: 6.4; 95% CI: 2.1, 11), and somatization (β: 3.8; 95% CI: 0.3, 7.3) scores. In contrast, triclosan-BASC-2 associations in girls were generally null and not statistically significant. We observed similar patterns of associations between childhood triclosan and these same behavioral scores; however, their magnitude decreased substantially after adjusting for gestational triclosan and associations were not statistically significant.

CONCLUSION

In this cohort, increasing gestational and childhood urinary triclosan concentrations were associated with higher behavior problem scores in 8-year old boys, but not girls.

Food components and environmental chemicals of inhibiting human placental aromatase

Human placental CYP19A1 catalyzes the estrogen synthesis from androgens. The enzyme is encoded by CYP19A1 gene located in chromosome 15q21. This enzyme is a monooxygenase in the smooth endoplasmic reticulum. The various promoters of the CYP19A1 gene determine its expression in different tissues and the distal promoter I.1 controls its expression in the placenta and retinoids can regulate the expression. Many food components and environmental chemicals inhibit CYP19A1 activity via different modes of action. These chemicals include gossypol, flavones, flavanones, chalconoids, resveratrol, and tobacco alkaloids derived from foods as well as phthalates, insecticides, fungicides, and biocides in the contaminated foods. The inhibition of placental CYP19A1 could impair pregnancy.