Systematic reviews and meta-analyses of human and animal evidence of prenatal diethylhexyl phthalate exposure and changes in male anogenital distance

Association between prenatal phthalate exposure and ano-genital indices among offsprings in an Israeli cohort

Background

In-utero phthalate exposure was shown to be associated with shortened anogenital distance (AGD) in male newborns, but findings among female are inconsistent. While phthalate exposure among pregnant women in Israel is widespread, no study has examined the association with offspring AGD. The objective of the current study was to investigate the association between maternal phthalates urinary concentration and offspring AGD at time of delivery among a birth cohort in Israel.

Methods

We measured spot urinary concentration of monobutyl phthalate (MBP), monobenzyl phthalate (MBzP), mono-2-ethyl-5-carboxypentyl phthalate (MECPP), mono-2-ethyl-5-hydroxyhexylphthalate (MEHHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP) among women presenting to the delivery room at Shamir Medical Center in Israel. Birthweight, length and AGD were measured in all newborns using a standardized protocol. Each AGD measurement was adjusted to weight (ano-genital index). Confounders included socio-demographic characteristics, comorbidities and obstetrical history. Univariate and multivariate analyses assessed the associations between phthalates, confounders and AGD.

Results

Overall, 193 mother and infant were analyzed. All newborns were born at term and had normal Apgar scores. Mean maternal age was 32 ± 4.7 years old. Mean birth weight and pregnancy week were 3183 ± 498 g and 39 ± 1.3, respectively. Median (IQR) urinary phthalate concentration adjusted to creatinine (ug/g) were 3.96 (2.2-6.6), 1.22 (0.7-2), 10.84 (7-20.4), 6.36 (3.3-11.2) and 0.64 (0.4-1.1) for MBP, MBzP, MECPP, MEHHP and MEOHP, respectively. Univariate comparison showed a significant association between higher than median MBzP concentration, higher Ano-Fourchetal index (AFI: 4.4 vs. 4.1, p = 0.037) and Ano-clitoral index (ACI: 11.5 vs. 10.4, p = 0.032) in infants. Total urinary phthalates concentration ≥26.25 μg/g was significantly associated with smaller penile width index (3.5 vs. 3.7, p = 0.022), higher ACI (11.6 vs. 10.3, p = 0.013) and a trend towards significance for higher AFI (4.3 vs. 4.1, p = 0.055). Following multivariate linear regression only PWI remained significantly associated with total phthalate urinary concentration.

Conclusions

Maternal urinary phthalates concentration at delivery were not associated with female AGD, but total urinary phthalate concentration were inversely associated with penile width.

Prenatal phthalate exposure and fetal penile length and width

BACKGROUND

Phthalates are endocrine-disrupting chemicals with anti-androgenic qualities and studies reported associations between prenatal phthalate exposure and infant genitalia. This study investigated whether increased prenatal phthalate exposure is associated with decreased fetal penile measures.

METHODS

Data was from the New York University Children's Health and Environment Study (2016-2019). Maternal urinary concentrations of 16 phthalate metabolites were quantified at <18 weeks gestation as a proxy for fetal exposure (n = 334 male pregnancies). We retrospectively measured penile length and width using ultrasounds conducted 18-24 weeks gestation (n = 173 fetuses). Associations of maternal urinary levels of phthalates with fetal penile length and width were determined using linear regression models.

RESULTS

57.2% of women were Hispanic, 31.8% Non-Hispanic White, 6.4% Asian, 2.3% Non-Hispanic Black, and 2.3% multiple races. Mean maternal age was 32 years (standard deviation [SD] = 5.7). Mean penile length was 7.13 mm (SD = 1.47) and width was 6.16 mm (SD = 0.87). An inverse relationship was observed between maternal levels of mono-ethyl phthalate and fetal penile length, and mono-(7-carboxy-n-heptyl) phthalate and penile width, though estimates were small and not significant when considering correction for multiple comparisons.

CONCLUSIONS

In our cohort we found no clinically meaningful associations between early pregnancy phthalate exposure and fetal penile length or width.

IMPACT

First-trimester phthalate metabolites were assessed in pregnant women in New York City. Penile length and width were retrospectively measured on clinically assessed ultrasounds conducted ≥18 weeks and <24 weeks of gestation. In this cohort, no clinically meaningful associations were observed between first-trimester prenatal phthalate exposure and fetal penile length. This study contributes to the limited but growing research on the impact of prenatal phthalate exposure on male fetal genital development. The results emphasize that there may not be a clear association between prenatal phthalate exposure and fetal penile length and width, and further research on this topic may be required.

Prenatal DEHP exposure induces lifelong testicular toxicity by continuously interfering with steroidogenic gene expression

Background

Epidemiologic studies suggested the association between prenatal di-(2-ethylhexyl) phthalate (DEHP) exposure and disorders of sex development (DSD), adult male disorders, and reproductive aging. Inhibiting testosterone synthesis by interfering with steroidogenic gene expression induces testicular toxicity, however, whether prenatal DEHP exposure induces testicular toxicity through this mechanism remains uncertain.

Methods

C57BL/6JGpt male mice underwent different doses (0, 100, 500, 1,000 mg/kg) of prenatal DEHP exposure during gestational day 10 to delivery day, the testicular toxicity (genital development, testosterone, semen quality, and morphology of testis tissue) in the neonatal, post-puberal and middle-aged stages was observed, and the steroidogenic gene (Lhcgr, Star, Cyp11a1, Cyp17a1, Hsd17b3, and Hsd3b2) expression was analyzed by quantitative polymerase chain reaction (qPCR) and Western blot (WB). The interference of steroidogenic gene expression in TM3 cells after mono-(2-ethylhexyl) phthalate (MEHP) exposure was also explored for verification.

Results

Prenatal DEHP exposure induced immediate testicular injury in the neonatal stage [reduced anogenital distance (AGD) and intratesticular testosterone], DSD in the post-puberal stage (poor genital development), and reproductive aging in the middle-aged stage (obesity, reduced testosterone and semen quality, and atrophic seminiferous tubules), especially in the high dose. Prenatal DEHP exposure continuously interfered with steroidogenic gene expression (Hsd3b2, Hsd17b3) in RNA and protein levels. MEHP inhibited testosterone synthesis of TM3 cells by interfering with steroidogenic gene expression (Hsd3b2, Hsd17b3) in RNA and protein levels.

Conclusions

Prenatal DEHP exposure induces lifelong testicular toxicity by continuously interfering with steroidogenic gene expression, thus indicating the association between prenatal exposure and DSD, adult male disorders, and reproductive aging.

Prenatal to peripubertal exposure to Di(2-ethylhexyl) phthalate induced endometrial atrophy and fibrosis in female mice

Di(2-ethylhexy) phthalate (DEHP) is a widely used plasticizer that is ubiquitously found in the environment. Using a mouse model, we investigated the impact of early life DEHP exposure ranging from the prenatal to peripubertal developmental period of the female reproductive system. Pregnant female mice were allocated to three groups as follows: control, 100 mg/kg/day, and 500 mg/kg/day DEHP treatment. DEHP exposure was introduced through feeding during pregnancy (3 weeks) and lactation (3 weeks). After weaning, the offspring were also exposed to DEHP through feeding for another 2 weeks. Observations were conducted on female offspring at 10 and 24 weeks. The number of live offspring per dam was significantly lower in the high-DEHP-exposed group (500 mg/kg/day) compared to the control group (7.67 ± 1.24 vs. 14.17 ± 0.31; p < 0.05) despite no difference in pregnancy rates across the groups. Low-DEHP exposure (100 mg/kg/day) resulted to a decreased body weight (36.07 ± 3.78 vs. 50.11 ± 2.11 g; p < 0.05) and decreased left uterine length (10.60 ± 1.34 vs. 14.77 ± 0.82 mm; p < 0.05) in 24-week- old female mice. As early as 10 weeks, endometrial atrophy and fibrosis were observed, and endometrial cystic hyperplasia was noted in female mice at 24 weeks. Our study is the first to demonstrate that female mice exposed to DEHP in the early life developed endometrial fibrosis in the female offspring. Further studies on the consequences of these observations in fecundity and other reproductive functions are warranted.

Mitochondrial dysfunction and endoplasmic reticulum stress induced by activation of PPARα leaded testicular to apoptosis in SD rats explored to di-(2-ethylhexyl) phthalate (DEHP)

Di-2-ethylhexyl phthalate (DEHP), as a common endocrine disrupting chemicals, can induce toxicity to reproductive system. However, the mechanism remains to be explored. In our study, DEHP exposure induced testicular injury in rats. The high throughput transcriptional sequencing was performed to identify differentially expressed genes (DEGs) between the treatment and control groups. KEGG analysis revealed that DEGs were enriched in apoptosis, PPARα, and ER stress pathway. DEHP up-regulated the expression of PPARα, Bax, Bim, caspase-4. GRP78, PERK, p-PERK, eIF2α, p-eIF2α, ATF4 and CHOP. This view has also been confirmed in TM3 and TM4 cells. In vitro, after pre-treatment with GW6471 (an inhibitor of PPARα) or GSK (an inhibitor of PERK), the apoptosis was inhibited and mitochondrial dysfunction was improved. Moreover, the improvement of mitochondrial dysfunction decreased the expression of PERK pathway by using SS-31(a protective agent for mitochondrial function). Interestingly, ER stress promoted the accumulation of ROS by ERO1L (the downstream of CHOP during ER stress), and the ROS further aggravated the ER stress, thus forming a feedback loop during the apoptosis. In this process, a vicious cycle consisting of PERK, eIF2α, ATF4, CHOP, ERO1L, ROS was involved. Taken together, our results suggested that mitochondrial dysfunction and ER stress-ROS feedback loop caused by PPARα activation played a crucial role in DEHP-induced apoptosis. This work provides insight into the mechanism of DEHP-induced reproductive toxicity.

Environmentally relevant DEHP exposure during gestational and lactational period inhibits filamin a testicular expression

Toxicological studies have revealed that DEHP exposure during pregnancy may induce developmental disorders, especially in male offspring, leading to morphological and functional alterations in the reproductive system by mechanisms that should be investigated. Thus, the aim of this work was to analyze the testicular toxicity induced by an environmentally relevant DEHP dose during development and its impact on FLNA, a protein that participates in the blood-testis barrier assembly. We used male Wistar rats exposed to DEHP during pregnancy and lactation. The results showed that DEHP exposure during development and lactation increased body weight, decreased gonadal weight and shortened anogenital distance. This phthalate induced morphological changes in the testis, suggestive of hypospermatogenesis. DEHP exposure decreased the number of FLNA positive cells and the expression of FLNA and claudin-1 in prepubertal testes. Furthermore, DEHP inhibited FLNA and claudin-1 protein expression in adult male rats. These results indicated that exposure to DEHP during gestation and lactation perturbed testis development and suggested that FLNA is a target protein of DEHP, possibly contributing to the phthalate-induced damage on BTB.

Epigallocatechin gallate alleviates mono-2-ethylhexyl phthalate-induced male germ cell pyroptosis by inhibiting the ROS/mTOR/NLRP3 pathway

Mono-2-ethylhexyl phthalate (MEHP) exposure is known to induce severe testicular injury via reactive oxygen species (ROS). However, few effective treatments are available for the precise treatment of MEHP-induced germ cell damage. Epigallocatechin gallate (EGCG), one of the major polyphenols in green tea, has potential antioxidant activity and can alleviate many diseases induced by oxidative stress. This study explored whether EGCG protects germ cells from MEHP-induced oxidative stress damage. Cells were treated with 400 μM MEHP and 60 μM EGCG for 24 h. EGCG reduced MEHP-induced ROS overgeneration in the spermatogonial cell line GC-1 and spermatocyte cell line GC-2. Western blotting and immunofluorescence showed that the MEHP+EGCG group exhibited lower nuclear factor (erythroid-derived 2)-like 2 (NRF2), heme oxygenase (decycling) 1 (HO-1), and superoxide dismutase (SOD) expression than the MEHP group. Moreover, activation of the mammalian target of rapamycin (mTOR) pathway was decreased. The expression of key factors of pyroptosis was downregulated, and interleukin-10 (IL-10) expression was reduced. Additionally, apoptosis was inhibited by EGCG. The findings indicate that EGCG protects against MEHP-induced germ cell pyroptosis by scavenging ROS, suppressing the mTOR pathway, and inhibiting pyroptosis. EGCG may thus be a potential treatment for MEHP-related spermatogenic dysfunction.

Phthalate levels in prenatal and postnatal bedroom dust in the SELMA study

Phthalates are common in polyvinyl chloride (PVC) plastics and numerous consumer goods in our homes from which they can migrate and adhere to indoor dust particles. It is known that indoor dust exposure contribute to human phthalate intake; however, there is a lack of large studies with a repeated-measure design investigating how phthalate levels in indoor dust may vary over time in people's homes. This study investigated levels of seven phthalates and one alternative plasticiser di-iso-nonyl-cyclohexane-di-carboxylate (DiNCH) in bedroom dust collected prenatally around week 25 during pregnancy and postnatally at six months after birth, from 496 Swedish homes. Prenatal and postnatal phthalate levels were compared using correlation and season-adjusted general linear regression models. Over the nine-month period, levels of six out of seven phthalates were associated as indicated by a positive Pearson correlation (0.18 < r < 0.50, P < .001) and Lin's concordance correlation between matched prenatal and postnatal dust samples. Compared to prenatal levels, the season-adjusted postnatal levels decreased for five phthalates, whilst di-ethyl-hexyl phthalate (DEHP), di-2-propylheptyl phthalate (DPHP) and DiNCH increased. The results suggest that families with higher phthalate levels in bedroom dust during pregnancy are likely to remain among those with higher levels in the infancy period. However, all average phthalate levels changed over this specific nine-month period suggesting that available phthalate sources or their use were altered between the dust collections. Changes in home characteristics, family lifestyle, and phthalate replacement trends may contribute to explain the differences.

Associations of maternal anthropometrics with newborn anogenital distance and the 2:4 digit ratio

STUDY QUESTION

Are maternal anthropometrics associated with anogenital distance (AGD) and 2:4 digit ratio (2:4D) in newborns?

SUMMARY ANSWER

Select maternal anthropometrics indicative of obesity or increased adiposity are associated with elongated AGD in daughters.

WHAT IS KNOWN ALREADY

Excessive maternal weight or adiposity before or in early pregnancy may impact child reproductive, and other hormonally mediated, development. AGD and 2:4D are proposed markers of in utero reproductive development.

STUDY DESIGN, SIZE, DURATION

This study includes 450 mother/newborn dyads participating in the Illinois Kids Development Study (I-KIDS), a prospective pregnancy cohort from Champaign-Urbana, IL, USA. Participants included in the current study enrolled between 2013 and 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Most mothers in this study were college-educated (82%) and non-Hispanic White (80%), and 55% were under- or normal weight before pregnancy. Pregnant women aged 18-40 years reported pre-pregnancy weight and height to calculate pre-pregnancy BMI. At 8-15 weeks gestation, we measured waist and hip circumference, and evaluated weight, % body fat, visceral fat level, % muscle and BMI using bioelectrical impedance analysis. Within 24 h of birth, we measured newborn 2nd and 4th left/right digits to calculate the 2:4D. In daughters, we measured AGDAF (anus to fourchette) and AGDAC (anus to clitoris). In sons, we measured AGDAS (anus to scrotum) and AGDAP (anus to base of the penis).

MAIN RESULTS AND THE ROLE OF CHANCE

Select maternal anthropometrics were positively associated with AGD in newborn daughters, but not sons. For example, AGDAC was 0.73 mm (95% CI: 0.15, 1.32) longer for every interquartile range (IQR) increase in pre-pregnancy BMI and 0.88 mm (95% CI: 0.18, 1.58) longer for every IQR increase in hip circumference, whereas AGDAF was 0.51 mm (95% CI: 0.03, 1.00) and 0.56 mm (95% CI: 0.03, 1.09) longer for every IQR increase in hip and waist circumference, respectively. Quartile analyses generally supported linear associations, but additional strong associations emerged in Q4 (versus Q1) of maternal % body fat and visceral fat levels with AGDAC. In quartile analyses, we observed only a few modest associations of maternal anthropometrics with 2:4D, which differed by hand (left versus right) and newborn sex. Although there is always the possibility of spurious findings, the associations for both measures of female AGD were consistent across multiple maternal anthropometric measures, which strengthens our conclusions.

LIMITATIONS, REASONS FOR CAUTION

Our study sample was racially and ethnically homogenous, educated and relatively healthy, so our study may not be generalizable to other populations. Additionally, we may not have been powered to identify some sex-specific associations, especially for 2:4D.

WIDER IMPLICATIONS OF THE FINDINGS

Increased maternal weight and adiposity before and in early pregnancy may lengthen the female AGD, which warrants further investigation.

STUDY FUNDING/COMPETING INTEREST(S)

This publication was made possible by the National Institute for Environmental Health Sciences (NIH/NIEHS) grants ES024795 and ES022848, the National Institute of Child Health and Human Development grant R03HD100775, the U.S. Environmental Protection Agency grant RD83543401 and National Institute of Health Office of the Director grant OD023272. Its contents are solely the responsibility of the grantee and do not necessarily represent the official views of the US EPA or NIH. Furthermore, the US EPA does not endorse the purchase of any commercial products or services mentioned in the publication. This project was also supported by the USDA National Institute of Food and Agriculture and Michigan AgBioResearch. The authors declare no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Whole blood analysis for medical diagnostics by GC-MS with Cold EI

This study covers a new method and related instrumentation for whole blood analysis for medical diagnostics. Two-μL whole blood samples were collected using "minimal invasive" diabetes lancet and placed on a thin glass rod mounted on a newly designed BloodProbe. The BloodProbe with the whole blood sample was inserted directly into a ChromatoProbe mounted on the GC inlet, and thus, no sample preparation was involved. The analysis was performed within 10 min using a GC-MS with Cold EI that is based on interfacing GC and MS with supersonic molecular beams (SMB) along with electron ionization of vibrationally cold sample compounds in the SMB (hence the name Cold EI). Our blood analysis revealed several observations: (1) Detailed mass chromatograms were generated with full range of all the nonpolar lipids in blood including fatty acids, cholesterol, cholesteryl esters, vitamin E, monoglycerides, diglycerides, and triglycerides. (2) The analysis of whole blood was found to be as informative as the conventional clinical analysis of blood serum. (3) Cholesteryl esters were more sensitive than free cholesterol alone to the effect of diet of obese people. (4) Major enhancement of several fatty acid methyl esters was found in the blood of a cancer patient with liver dysfunction. (5) Vitamin E as both α- and β-tocopherol was found with person-dependent ratio of these two compounds. (6) Elemental sulfur S₈ was identified in blood. (7) Several drugs and other compounds were found and need further study of their correlation to medical issues.

DEHP induces ferroptosis in testes via p38α-lipid ROS circulation and destroys the BTB integrity

Exposure to Di (2-ethylhexyl) phthalate (DEHP) has been associated with toxic effects of the reproductive system. However, the exact mechanism remains to be elucidated. In this study we explored the testicular toxicity induced by DEHP, and the probable molecular mechanism in the process. In vivo, the results demonstrated that DEHP affected testosterone levels and blood-testosterone barrier (BTB) integrity and caused ferroptosis. We further demonstrated that DEHP up-regulated the expression of p38α, p-p38α, p53, p-p53, SAT1, ALOX15. This view has also been confirmed in TM4 cells. After pre-treatment with fer-1 or si-MAPK14, the expression of either p53, p-p53, SAT1 and ALOX15 up-regulated by MEHP was inhibited in vitro. Interestingly, p38α can prevent the accumulation of lipid ROS, and the production of lipid ROS in turn promoted the expression of p38α, thus forming a feedback loop during the ferroptosis. In this process, a vicious cycle consisting of p38α, p53, SAT1, ALOX15, lipid ROS was involved. This study provides new mechanistic insights into DEHP-induced toxicity of the reproductive system.

Innovation in regulatory approaches for endocrine disrupting chemicals: The journey to risk assessment modernization in Canada

Globally, regulatory authorities grapple with the challenge of assessing the hazards and risks to human and ecosystem health that may result from exposure to chemicals that disrupt the normal functioning of endocrine systems. Rapidly increasing number of chemicals in commerce, coupled with the reliance on traditional, costly animal experiments for hazard characterization - often with limited sensitivity to many important mechanisms of endocrine disruption -, presents ongoing challenges for chemical regulation. The consequence is a limited number of chemicals for which there is sufficient data to assess if there is endocrine toxicity and hence few chemicals with thorough hazard characterization. To address this challenge, regulatory assessment of endocrine disrupting chemicals (EDCs) is benefiting from a revolution in toxicology that focuses on New Approach Methodologies (NAMs) to more rapidly identify, prioritize, and assess the potential risks from exposure to chemicals using novel, more efficient, and more mechanistically driven methodologies and tools. Incorporated into Integrated Approaches to Testing and Assessment (IATA) and guided by conceptual frameworks such as Adverse Outcome Pathways (AOPs), emerging approaches focus initially on molecular interactions between the test chemical and potentially vulnerable biological systems instead of the need for animal toxicity data. These new toxicity testing methods can be complemented with in silico and computational toxicology approaches, including those that predict chemical kinetics. Coupled with exposure data, these will inform risk-based decision-making approaches. Canada is part of a global network collaborating on building confidence in the use of NAMs for regulatory assessment of EDCs. Herein, we review the current approaches to EDC regulation globally (mainly from the perspective of human health), and provide a perspective on how the advances for regulatory testing and assessment can be applied and discuss the promises and challenges faced in adopting these novel approaches to minimize risks due to EDC exposure in Canada, and our world.

Effects of endocrine disrupting chemicals on gonad development: Mechanistic insights from fish and mammals

Over the past century, evidence has emerged that endocrine disrupting chemicals (EDCs) have an impact on reproductive health. An increased frequency of reproductive disorders has been observed worldwide in both wildlife and humans that is correlated with accidental exposures to EDCs and their increased production. Epidemiological and experimental studies have highlighted the consequences of early exposures and the existence of key windows of sensitivity during development. Such early in life exposures can have an immediate impact on gonadal and reproductive tract development, as well as on long-term reproductive health in both males and females. Traditionally, EDCs were thought to exert their effects by modifying the endocrine pathways controlling reproduction. Advances in knowledge of the mechanisms regulating sex determination, differentiation and gonadal development in fish and rodents have led to a better understanding of the molecular mechanisms underlying the effects of early exposure to EDCs on reproduction. In this manuscript, we review the key developmental stages sensitive to EDCs and the state of knowledge on the mechanisms by which model EDCs affect these processes, based on the roadmap of gonad development specific to fish and mammals.

Prenatal phthalate exposure in relation to placental corticotropin releasing hormone (pCRH) in the CANDLE cohort

CONTEXT

Phthalates may disrupt maternal-fetal-placental endocrine pathways, affecting pregnancy outcomes and child development. Placental corticotropin releasing hormone (pCRH) is critical for healthy pregnancy and child development, but understudied as a target of endocrine disruption.

OBJECTIVE

To examine phthalate metabolite concentrations (as mixtures and individually) in relation to pCRH.

DESIGN

Secondary data analysis from a prospective cohort study.

SETTING

Prenatal clinics in Tennessee, USA.

PATIENTS

1018 pregnant women (61.4% non-Hispanic Black, 32% non-Hispanic White, 6.6% other) participated in the CANDLE study and provided data. Inclusion criteria included: low-medical-risk singleton pregnancy, age 16-40, and gestational weeks 16-29.

INTERVENTION

None.

MAIN OUTCOME MEASURES

Plasma pCRH at two visits (mean gestational ages 23.0 and 31.8 weeks) and change in pCRH between visits (ΔpCRH).

RESULTS

In weighted quantile sums (WQS) regression models, phthalate mixtures were associated with higher pCRH at Visit 1 (β = 0.07, 95 %CI: 0.02, 0.11) but lower pCRH at Visit 2 (β = -0.08, 95 %CI: -0.14, -0.02). In stratified analyses, among women with gestational diabetes (n = 59), phthalate mixtures were associated with lower pCRH at Visit 1 (β = -0.17, 95 %CI: -0.35, 0.0006) and Visit 2 (β = -0.35, 95 %CI: -0.50, -0.19), as well as greater ΔpCRH (β = 0.16, 95 %CI: 0.07, 0.25). Among women with gestational hypertension (n = 102), phthalate mixtures were associated with higher pCRH at Visit 1 (β = 0.20, 95 %CI: 0.03, 0.36) and Visit 2 (β = 0.42; 95 %CI: 0.19, 0.64) and lower ΔpCRH (β = -0.17, 95 %CI: -0.29, -0.06). Significant interactions between individual phthalate metabolites and pregnancy complications were observed.

CONCLUSIONS

Phthalates may impact placental CRH secretion, with differing effects across pregnancy. Differences in results between women with and without gestational diabetes and gestational hypertension suggest a need for further research examining whether women with pregnancy complications may be more vulnerable to endocrine-disrupting effects of phthalates.

Human health impacts of exposure to phthalate plasticizers: An overview of reviews

In this review of reviews, we overview the current global body of available evidence from structured reviews of epidemiological studies that explore human health outcomes associated with exposure to phthalates (chemical plasticisers commonly found in plastics). We found robust evidence for an association with lower semen quality, neurodevelopment and risk of childhood asthma, and moderate to robust evidence for impact on anogenital distance in boys. We identified moderate evidence for an association between phthalates/metabolites and low birthweight, endometriosis, decreased testosterone, ADHD, Type 2 diabetes and breast/uterine cancer. There was some evidence for other outcomes including anofourchette distance, fetal sex hormones, pre-term birth, lower antral follicle count, reduced oestrodiol, autism, obesity, thyroid function and hearing disorders. We found no reviews of epidemiological human studies on the impact of phthalates from recycled plastics on human health. We recommend that future research should use urine samples as exposure measures, consider confounders in analyses and measure impacts on female reproductive systems. Our findings align with emerging research indicating that health risks can occur at exposure levels below the "safe dose" levels set out by regulators, and are of particular concern given potential additive or synergistic "cocktail effects" of chemicals. This raises important policy and regulatory issues for identifying and controlling plastics and health related impacts and highlights a need for more research into substances of concern entering plastics waste streams via recycling.

A mixture of 15 phthalates and pesticides below individual chemical no observed adverse effect levels (NOAELs) produces reproductive tract malformations in the male rat

Humans carry residues of multiple synthetic chemicals at any given point in time. Research has demonstrated that compounds with varying molecular initiating events (MIE) that disrupt common key events can act in concert to produce cumulative adverse effects. Congenital defects of the male reproductive tract are some of the most frequently diagnosed malformations in humans and chemical exposures in utero can produce these effects in laboratory animals and humans. Here, we hypothesized that in utero exposure to a mixture of pesticides and phthalates, each of which produce male reproductive tract defects individually, would produce cumulative effects even when each chemical is present at a no observed adverse effect level (NOAEL) specific for male reproductive effects. Pregnant Sprague-Dawley rats were exposed via oral gavage to a fixed-ratio dilution mixture of 5 pesticides (vinclozolin, linuron, procymidone, prochloraz, pyrifluquinazon), 1 pesticide metabolite (dichlorodiphenyldichloroethylene (DDE)), and 9 phthalates (dipentyl, dicyclohexyl, di-2-ethylhexyl, dibutyl, benzyl butyl, diisobutyl, diisoheptyl, dihexyl, and diheptyl) during the critical window of rat fetal masculinization (gestation day 14-18). The top dose (100% dose) contained each compound at a concentration 2-fold greater than the individual chemical NOAEL followed by a dilution series that represented each chemical at NOAEL, NOAEL/2, NOAEL/4, NOAEL/8, NOAEL/15, NOAEL/100, NOAEL/1000. Reduced fetal testis gene expression occurred at NOAEL/15, reduced fetal testis testosterone production occurred at NOAEL/8, reduced anogenital distance, increased nipple retention, and delayed puberty occurred at NOAEL/4, and severe effects including genital malformations and weight reductions in numerous reproductive tissues occurred at NOAEL/2. This study demonstrates that these phthalates and pesticides acted cumulatively to produce adverse effects at doses below which any individual chemical had been shown to produce an effect alone and even though they have different MIEs.

Buy-now-pay-later: Hazards to human and planetary health from plastics production, use and waste

More than 8 billion tonnes of plastic were produced between 1950 and 2015, that is 1 tonne for every man, woman and child on our planet. Global plastic production has been growing exponentially with an annual growth rate of 8.4% since 1950, equating to approximately 380 million tonnes per annum. A further 50 kg of plastic is now being produced for each person every year with production continuing to accelerate. Here, we discuss the human and planetary health hazards of all that plastic. We consider each step in the journey of these complex and pervasive industrial materials: from their synthesis predominantly from fossil fuel feedstocks, through an often-brief consumer use as plastic products, and onto waste streams as fuel, permanent landfill or as unmanaged waste in our environment, food, air and bodies.

COVID-19 discarded disposable gloves as a source and a vector of pollutants in the environment

The appearance of the virus SARS-CoV-2 at the end of 2019 and its spreading all over the world has caused global panic and increase of personal protection equipment usage to protect people against infection. Increased usage of disposable protective gloves, their discarding to random spots and getting to landfills may result in significant environmental pollution. The knowledge concerning possible influence of gloves and potential of gloves debris on the environment (water, soil, etc.), wildlife and humans is crucial to predict future consequences of disposable gloves usage caused by the pandemic. This review focuses on the possibility of chemical release (heavy metals and organic pollutants) from gloves and gloves materials, their adsorptive properties in terms of contaminants accumulation and effects of gloves degradation under environmental conditions.

Indoor phthalate exposure and contributions to total intake among pregnant women in the SELMA study

Phthalates are widely used in consumer products. Exposure to phthalates can lead to adverse health effects in humans, with early-life exposure being of particular concern. Phthalate exposure occurs mainly through ingestion, inhalation, and dermal absorption. However, our understanding of the relative importance of different exposure routes is incomplete. This study estimated the intake of five phthalates from the residential indoor environment for 455 Swedish pregnant women in the SELMA study using phthalate mass fraction in indoor dust and compares these to total daily phthalate intakes back-calculated from phthalate metabolite concentrations in the women's urine. Steady-state models were used to estimate indoor air phthalate concentrations from dust measurements. Intakes from residential dust and air made meaningful contributions to total daily intakes of more volatile di-ethyl phthalate (DEP), di-n-butyl phthalate (DnBP), and di-iso-butyl phthalate (DiBP) (11% of total DEP intake and 28% of total DnBP and DiBP intake combined). Dermal absorption from air was the dominant pathway contributing to the indoor environmental exposure. Residential exposure to less volatile phthalates made minor contributions to total intake. These results suggest that reducing the presence of low molecular weight phthalates in the residential indoor environment can meaningfully reduce phthalate intake among pregnant women.

In utero exposure to phthalates and reproductive toxicity in rodents

Phthalates, widely used as plasticizers, are contained in many everyday products. Human biomonitoring studies detect their presence in biological fluids of a large part of the population worldwide. Maternal exposure during pregnancy has been related with aberrations in the reproductive growth of male infants. Rodent studies show that gestational exposure to single phthalates elicits reproductive toxicity in both sexes. Early aberrations include inhibition of gonadal sex determining gene expression and steroidogenesis, histopathology, and disturbed gametogenesis, leading later in life to dysfunctions in sperm production and oocyte reserves. Animal studies of in utero exposure to mixtures of phthalates, better mimicking human exposures, revealed analogous reproductive dysfunctions with the single compounds, but also indicated the combined actions and cumulative effects exerted by these chemicals. Further understanding the underlying mechanisms and the species differences in phthalate-induced reproductive toxicity will help to improve the risk assessment for human exposure to these toxicants.

Androgens and the masculinization programming window: human-rodent differences

Human male reproductive disorders are common and may have a fetal origin - the testicular dysgenesis syndrome (TDS) hypothesis. In rats, experimentally induced TDS disorders result from disruption of fetal androgen production/action specifically in the masculinization programming window (MPW). MPW androgen action also programs longer anogenital distance (AGD) in male versus female rats; shorter male AGD is correlated with risk and severity of induced TDS disorders. AGD thus provides a lifelong, calibrated readout of MPW androgen exposure and predicts likelihood of reproductive dysfunction. Pregnant rat exposure to environmental chemicals, notably certain phthalates (e.g. diethyl hexl phthalate, DEHP; dibutyl phthalate, DBP), pesticides or paracetamol, can reduce fetal testis testosterone and AGD and induce TDS disorders, provided exposure includes the MPW. In humans, AGD is longer in males than females and the presumptive MPW is 8-14 weeks' gestation. Some, but not all, epidemiological studies of maternal DEHP (or pesticides) exposure reported shorter AGD in sons, but this occurred at DEHP exposure levels several thousand-fold lower than are effective in rats. In fetal human testis culture/xenografts, DEHP/DBP do not reduce testosterone production, whereas therapeutic paracetamol exposure does. In humans, androgen production in the MPW is controlled differently (human chorionic gonadotrophin-driven) than in rats (paracrine controlled), and other organs (placenta, liver, adrenals) contribute to MPW androgens, essential for normal masculinization, via the 'backdoor pathway'. Consequently, early placental dysfunction, which is affected by maternal lifestyle and diet, and maternal painkiller use, may be more important than environmental chemical exposures in the origin of TDS in humans.

c-Fos is upregulated in the genital tubercle of DEHP-induced hypospadiac rats and the prepuce of patients with hypospadias

This study aimed to investigate the expression of Fos proto-oncogene, AP-1 transcription factor subunit (c-Fos) in the genital tubercle (GT) of rats with di(2-ethylhexyl) phthalate (DEHP)-induced hypospadias and in the prepuce of patients with hypospadias compared with unaffected controls. Pregnant rats were given 750 mg/kg/day DEHP orally from gestational days 12-19. Western blotting showed that c-Fos expression was increased in DEHP-induced hypospadiac male offspring. In addition, 30 prepuce tissue specimens obtained during hypospadias repair surgery were divided into 2 groups: the mild hypospadias group (n = 15) and the severe hypospadias group (n = 15). Fifteen normal prepuce tissue specimens were harvested during elective circumcision as normal controls. Real-time quantitative polymerase chain reaction, western blotting and immunohistochemistry analyses were used to assess c-Fos expression. c-Fos protein levels were higher in the GT of DEHP-induced rats than in that of control rats. c-Fos mRNA and protein levels were also higher in the hypospadias groups than in the control group (p < 0.05, p < 0.001), and c-Fos protein levels were significantly higher in the severe hypospadias group than in the mild hypospadias group (p < 0.01). The expression of c-Fos was increased in both the GT of DEHP-induced hypospadiac rats and the prepuce of hypospadias patients. Thus, c-Fos overexpression might contribute to hypospadias.Abbreviations: DEHP: di(2-ethylhexyl) phthalate; c-Fos: Fos proto-oncogene, AP-1 transcription factor subunit; Mafb: the masculinization-regulatory gene v-maf musculoaponeurotic fibrosarcoma oncogene family, protein B; GT: genital tubercle; ED: embryonic day; AGD: anogenital distance; AGI: anogenital distance index; ED: embryonic day.

Development of a physiologically based pharmacokinetic model of diisononyl phthalate (DiNP) in pregnant rat and human

A physiologically based pharmacokinetic (PBPK) model for di-isononyl phthalate (DiNP) was developed by adapting the existing models for di(2-ethylhexyl) phthalate (DEHP) and di-butylphthalate (DBP). Both pregnant rat and human time-course plasma and urine data were used to address the hydrolysis of DiNP in intestinal tract, plasma, and liver as well as hepatic oxidative metabolism and conjugation of the monoester and primary oxidative metabolites. Data in both rats and humans were available to inform the uptake and disposition of mono-isononyl phthalate (MiNP) as well as the three primary oxidative metabolites including hydroxy (7-OH)-, oxo (7-OXO)-, and carboxy (7-COX)-monoisononyl phthalate in plasma and urine. The DiNP model was reliable over a wide range of exposure levels in the pregnant rat as well as the two low exposure levels in humans including capturing the nonlinear behavior in the pregnant rat after repeated 750 mg/kg/day dosing. The presented DiNP PBPK model in pregnant rat and human, based upon an extensive kinetic dataset in both species, may provide a basis for assessing human equivalent exposures based upon either rodent or in vitro points of departure.

Prenatal and early childhood exposure to phthalates and childhood behavior at age 7 years

BACKGROUND

Emerging evidence suggests that phthalate exposure may be associated with behavior problems in children and that these associations may be sex specific.

METHODS

In a follow up study of 411 inner-city minority mothers and their children, mono-n-butyl phthalate (MnBP), monobenzyl phthalate (MBzP), monoisobutyl phthalate (MiBP), monethyl phthalate (MEP) and four di-2-ethylhexyl phthalate metabolites (DEHP) were quantified in maternal urine samples collected during the third trimester and in child urine samples at ages 3 and 5 years. The Conners' Parent Rating Scale-Revised: Long Form (CPRS) and Child Behavior Checklist (CBCL) were administered to the mothers to assess children's behavior problems at 7 years of age. The analysis included children with available measures of CBCL, CPRS and phthalates measured in maternal urine. We performed both Quasi-Poisson regression and a mixture analysis using Weighted Quantile Sum(WQS) regression to assess the risk for CPRS scores and for internalizing and externalizing behaviors (from the CBCL) following intra-uterine exposure to the phthalate metabolites for boys and girls separately.

RESULTS

Among boys, increases in in anxious-shy behaviors were associated with prenatal exposure to MBzP (Mean Ratio [MR] = 1.20, 95%CI 1.05-1.36) and MiBP (Mean Ratio (MR) = 1.22, 95%CI 1.02-1.47). Among girls, increases in perfectionism were associated with MBzP (MR = 1.15, 95%CI 1.01-1.30). In both boys and girls, increases in psychosomatic problems were associated with MiBP (MR = 1.28, 95%CI 1.02-1.60), and MnBP (MR = 1.28, 95%CI 1.02-1.59), respectively. Among girls, decreased hyperactivity was associated with two DEHP metabolites, mono(2-ethyl-5-oxohexyl) phthalate (MR = 0.83, 95%CI 0.71-0.98) and mono(2-ethyl-5-hydroxyhexyl) phthalate (MR = 0.85, 95%CI 0.72-0.99). Using weighted Quantile Sum logistic regression, no associations were found between the Weighted Quantile Sum (WQS) of phthalate metabolites and CPRS scores or externalizing and internalizing behaviors. Nonetheless, when the analysis was performed separately for DEHP and non-DEHP metabolites significant associations were found between the WQS of DEHP metabolites and social problems in boys (OR = 2.15, 95%CI 1.13-4.06, p-value = 0.02) anxious-shy problems in girls (OR = 2.19, 95%CI 1.15-4.16, p = 0.02), and emotional lability problems in all children (OR = 0.61, 95%CI 0.38-0.97, p = 0.04). MEHP and MEOHP were the most highly weighted DEHP metabolites in WQS mixture. The analysis performed with CBCL scale corroborated these associations.

CONCLUSION

Concentration of non-DEHP metabolites was associated with anxious-shy behaviors among boys. DEHP phthalate metabolites were associated with decreased hyperactivity and impulsivity among girls on CPRS scores. These findings lend further support to the adverse associations between prenatal phthalate exposure and childhood outcomes, and clearly suggest that such associations are sex and mixture specific.

Citrate ester substitutes for di-2-ethylhexyl phthalate: In vivo reproductive and in vitro cytotoxicity assessments

Di-2-ethylhexyl phthalate (DEHP) is frequently used as a plasticizer for wrapping films, in toys, and in medical devices. Previous studies demonstrated that DEHP in mouse reduced testicular and epididymis weights, suppressed levels of serum testosterone, luteinizing hormone, and follicle-stimulating hormone, and decreased synthesis of testosterone by Leydig cells. Due to these anti-androgenic effects of DEHP on the reproductive system, the aim of this study was to examine whether substitutes such as acetyl triethyl citrate (ATEC) and acetyl tributyl citrate (ATBC) also damaged the reproductive system. In particular, this study investigated the anti-androgenic effects and cytotoxicity of DEHP substitutes using castrated male Sprague--Dawley rats employing the in vivo Hershberger assay and in vitro mouse Leydig (TM3) cells and mouse fibroblast (NIH-3T3) cell lines. In the Hershberger assay, rats were administered testosterone propionate and ATEC or ATBC at 20, 100, or 500 mg/kg b.w./day or DEHP (500 mg/kg b.w./day). Controls received testosterone antagonist flutamide (positive control), testosterone only (negative control), or corn oil only (vehicle control). ATEC/ATBC treatment produced no significant differences compared with testosterone in 5-androgen-dependent tissues weights including ventral prostate, seminal vesicles, levator ani-bulbocavernosus muscle, Cowper's glands, and glans penis. In the 500 mg/kg ATBC group, there was a significant reduction in liver weight. The MTT assay revealed that cell viability of both TM3 and NIH-3T3 cells treated with ATEC was not markedly altered. However, ATBC significantly reduced TM3 and NIH-3T3 cell viability in a concentration-dependent manner. Further, ATBC reduced cell viability to greater extent in TM3 versus NIH-3T3 cells. Based upon the observed effects of citrate ester substitutes on reproductive tissue responses and cytotoxicity, ATEC compared to ATBC may be a better alternative to DEHP for potential commercial uses.

ABBREVIATIONS

ATEC: acetyl triethyl citrate; ATBC: acetyl tributyl citrate; CG: Cowper's glands; DEHP: di-2-ethylhexyl phthalate; DMEM: Dulbecco's modified Eagle's medium; DMSO: dimethyl sulfoxide; GP: glans penis; LABC: levator ani-bulbocavernosus muscle; MTT: methyl tetrazolium; NC: negative control; NT: untreated control; PC: positive control; SV: seminal vesicle; TP: testosterone propionate; VC: vehicle control; VP: ventral prostate.

DEHP induces neutrophil extracellular traps formation and apoptosis in carp isolated from carp blood via promotion of ROS burst and autophagy

Di (2-ethylhexyl) phthalate (DEHP), a widely spreading environmental endocrine disruptor, has been confirmed to adversely affect the development of animals and humans. The formation of neutrophil extracellular traps (NETs) termed NETosis, is a recently identified antimicrobial mechanism for neutrophils. Though previous researches have investigated inescapable role of the immunotoxicity in DEHP-exposed model, relatively little is known about the effect of DEHP on NETs. In this study, carp peripheral blood neutrophils were treated with 40 and 200 μmol/L DEHP to investigate the underlying mechanisms of DEHP-induced NETs formation. Through the morphological observation of NETs and quantitative analysis of extracellular DNA, we found that DEHP exposure induced NETs formation. Moreover, our results proved that DEHP could increase reactive oxygen species (ROS) levels, decrease the expression of the anti-autophagy factor (mTOR) and the anti-apoptosis gene Bcl-2, and increase the expression of pro-autophagy genes (Dynein, Beclin-1 and LC3B) and the pro-apoptosis factors (BAX, Fas, FasL, Caspase3, Caspase8, and Caspase9), thus promoting autophagy and apoptosis. These results indicate that DEHP-induced ROS burst stimulates NETs formation mediated by autophagy and increases apoptosis in carp neutrophils.

Taxifolin attenuates the developmental testicular toxicity induced by di-n-butyl phthalate in fetal male rats

Di-n-butyl phthalate (DBP) is widely used in consumer products as a plasticizer. Here, we report a natural product taxifolin that can attenuate developmental and reproductive toxicity of DBP. Pregnant rats were daily gavaged with 500 mg/kg DBP alone or together with taxifolin (10 and 20 mg/kg) from gestational day (GD) 12-21. At GD21, sera and testes of male fetus were collected. DBP significantly lowered serum testosterone level at 500 mg/kg and taxifolin can completely reverse its action. DBP caused abnormal aggregation of fetal Leydig cells and taxifolin can reverse it. DBP down-regulated the expression of the genes of cholesterol side-chain cleavage enzyme (Cyp11a1), 17β-hydroxysteroid dehydrogenase 3 (Hsd17b3), and insulin-like 3 (Insl3) and taxifolin can reverse its action. DBP increased malondialdehyde levels and decreased superoxide dismutase and glutathione peroxidase expression and taxifolin can reverse it. DBP increased incidence of multinucleated gonocytes and taxifolin can prevent it. Moreover, DBP lowered sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) and phosphorylated AMP-activated protein kinase (pAMPK) signalling and taxifolin antagonized DBP. In conclusion, in utero exposure to DBP caused developmental/reproductive toxicity of male offspring via increasing reactive oxygen species and taxifolin is an effective food component that completely reverses DBP-mediated action.

Predictors with regard to ingestion, inhalation and dermal absorption of estimated phthalate daily intakes in pregnant women: The Barwon infant study

Human exposure to phthalate chemicals, used in consumer product plastics, occurs throughout the day. Phthalate levels in pregnant women are associated with offspring health effects including obesity and neurodevelopmental problems. Knowledge of predictors of exposure is necessary in order to effectively reduce phthalate exposure. The present study aims to identify predictors of phthalate levels in Australian pregnant women from the Barwon Infant study birth cohort. Maternal urine samples from 841 women were analyzed for phthalate metabolites. Maternal diet and food preparation practices, use of volatile household products, household characteristics and personal care product use were assessed with questionnaires. All maternal urine contained phthalate metabolites. Maternal prenatal high-fat milk consumption was associated with higher benzyl butyl phthalate (BBzP) (p < 0.001), and bis(2-ethylhexyl) phthalate (DEHP) (p = 0.0023). Higher phthalate levels were associated with consumption of tinned food (fish and tomatoes). Diethyl phthalate (DEP) levels were significantly higher when women reported using air freshener (35% increase, p = 0.01), aerosols (40% increase, p = 0.005), hair treatment chemicals (28% increase, p = 0.031), and chlorine (34% increase, p = 0.009) compared to no use. Maternal phthalate levels did not vary by reported plastic avoidance during pregnancy. The study showed that phthalate exposure is ubiquitous and increased by multiple factors. Future intervention studies to reduce phthalate levels among pregnant women will need to take into account the variety of sources identified in this study.

Anogenital distance in newborn infants conceived by assisted reproduction and natural conception

RESEARCH QUESTION

Does anogenital distance (AGD) differ in newborn infants conceived through assisted reproduction technology (ART) compared with those conceived naturally?

DESIGN

This case-control study looked at anthropometric and anogenital measurements in 247 male and 200 female newborns born after ART (n = 121) or natural conception (n = 326), within 24 h of birth. Anogenital measurements included distance from the centre of the anus to the anterior clitoris (AGDAC) and to the posterior fourchette (AGDAF) in female infants, and from the centre of the anus to the posterior base of the scrotum (AGDAS) and to the anterior base of the penis (AGDAP) in male infants.

RESULTS

ART mothers were older, more likely to be nulliparous and delivered by Caesarean section at an earlier gestational week. AGDAS of male infants was approximately twice the AGDAF of female infants (17.6 ± 5.0 versus 9.1 ± 3.6 mm). AGDAF in female infants conceived by ART compared with those conceived naturally was not significantly different (8.8 ± 3.6 versus 9.3 ± 3.6 mm; P = 0.404). AGDAC were also comparable for both groups (27.4 ± 6.3 versus 27.7 ± 7.1 mm; P = 0.770). In male infants, no significant difference was seen between ART and natural conception groups in terms of AGDAS (17.4 ± 4.6 versus 17.7 ± 5.2 mm, P = 0.742) and AGDAP (37.5 ± 6.6 versus 38.0 ± 6.7 mm, P = 0.589). When adjusted for gestational age, weight, length and head circumference, mode of conception was not associated with differences in any of the anogenital measurements.

CONCLUSIONS

AGD measurements in infants conceived by ART are no different from those of infants conceived naturally.

Prenatal perfluoroalkyl substances and newborn anogenital distance in a Canadian cohort

Exposure to the man-made chemicals perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS) and perfluorohexanesulfonate (PFHxS) is widespread. These perfluoroalkyl substances (PFASs) have been associated with androgenic endocrine-disrupting properties; however, the evidence is equivocal and few human studies have examined the association between prenatal exposure to PFASs and markers of androgenic endocrine disruption such as changes in anogenital distance (AGD). In the MIREC cohort, PFOA, PFOS and PFHxS were analyzed in first trimester maternal plasma. AGD was measured in 205 male and 196 female newborns. The change in estimate procedure was used to identify confounders by sex and AGD in multiple linear regression models. Geometric mean plasma concentrations (95% CI) for PFOA, PFOS and PFHxS were 1.71 (1.61, 1.81), 4.40 (4.18, 4.64) and 1.15 (1.06, 1.25) μg/L, respectively. A one-unit increase in natural log transformed PFOA was associated with a 1.36 mm (95% CI 0.30, 2.41) increase in anoscrotal distance, adjusting for household income, active smoking status during pregnancy and gestational age. However, when examined by quartiles, a non-monotonic pattern was observed with wide confidence intervals. No consistent patterns were observed between maternal PFAS concentrations and female AGDs. This study found no clear evidence that maternal plasma concentrations of PFOS, PFOA or PFHxS were associated with shorter infant anogenital distance in males or any change in AGD in females. Whether the positive association observed between longer anoscrotal distance and PFOA is real or would have any long-lasting effect on the reproductive health of males is unknown and needs to be investigated further.

Trends and Patterns of Phthalates and Phthalate Alternatives Exposure in Pregnant Women from Mexico City during 2007-2010

Phthalates are associated with several adverse health outcomes, but few studies have evaluated phthalate exposures in Mexican populations, particularly pregnant women. Between 2007 and 2011, 948 pregnant women from Mexico City were recruited as part of the PROGRESS cohort. We quantified 17 metabolites of phthalates and phthalate alternatives in urine samples collected during the second and third trimesters and examined temporal trends of metabolite concentrations, within-person reproducibility, and relations of individual metabolites with sociodemographic, lifestyle, and occupational factors. Concentrations of mono-2-ethyl-5-carboxypentyl terephthalate, a metabolite of the alternative phthalate di-2-ethylhexyl terephthalate, increased monotonically from 2007 to 2010 (31% per year; 95% confidence interval = 23 and 39%). We observed moderate to high correlations among metabolites collected at the same visit, but there was high variability between second and third trimester phthalate metabolite concentrations (intraclass correlation coefficients = 0.17-0.35). In general, higher socioeconomic status was associated with higher phthalate concentrations. Some metabolites were associated with maternal age and education, but no consistent patterns were observed. Women working in the home and those who worked in administration had higher concentrations of several phthalate metabolites relative to students, professionals, and those in customer service. Biomonitoring efforts are warranted to investigate present and future exposure trends and patterns.

A suggested bisphenol A metabolite (MBP) interfered with reproductive organ development in the chicken embryo while a human-relevant mixture of phthalate monoesters had no such effects

Bisphenol A (BPA) and phthalate diesters are ubiquitous environmental contaminants. While these compounds have been reported as reproductive toxicants, their effects may partially be attributed to metabolites. The aim of this study was to examine reproductive organ development in chicken embryos exposed to the BPA metabolite, 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP; 100 µg/g egg) or a human-relevant mixture of 4 phthalate monoesters (85 µg/g egg). The mixture was designed within the EU project EDC-MixRisk based upon a negative association with anogenital distance in boys at 21 months of age in a Swedish pregnancy cohort. Chicken embryos were exposed in ovo from an initial stage of gonad differentiation (embryonic day 4) and dissected two days prior to anticipated hatching (embryonic day 19). No discernible effects were noted on reproductive organs in embryos exposed to the mixture. MBP-treated males exhibited retention of Müllerian ducts and feminization of the left testicle, while MBP-administered females displayed a diminished the left ovary. In the left testicle of MBP-treated males, mRNA expression of female-associated genes was upregulated while the testicular marker gene SOX9 was downregulated, corroborating a feminizing effect by MBP. Our results demonstrate that MBP, but not the phthalate monoester mixture, disrupts both male and female reproductive organ development in an avian embryo model.

Review of the Effects of Perinatal Exposure to Endocrine-Disrupting Chemicals in Animals and Humans

Maternal exposure to endocrine-disrupting chemicals (EDCs) is associated with long-term hormone-dependent effects that are sometimes not revealed until maturity, middle age, or adulthood. The aim of this study was to conduct descriptive reviews on animal experimental and human epidemiological evidence of the adverse health effects of in utero and lactational exposure to selected EDCs on the first generation and subsequent generation of the exposed offspring. PubMed, Web of Science, and Toxline databases were searched for relevant human and experimental animal studies on 29 October 29 2018. Search results were screened for relevance, and studies that met the inclusion criteria were evaluated and qualitative data extracted for analysis. The search yielded 73 relevant human and 113 animal studies. Results from studies show that in utero and lactational exposure to EDCs is associated with impairment of reproductive, immunologic, metabolic, neurobehavioral, and growth physiology of the exposed offspring up to the fourth generation without additional exposure. Little convergence is seen between animal experiments and human studies in terms of the reported adverse health effects which might be associated with methodologic challenges across the studies. Based on the available animal and human evidence, in utero and lactational exposure to EDCs is detrimental to the offspring. However, more human studies are necessary to clarify the toxicological and pathophysiological mechanisms underlying these effects.

Update of the risk assessment of di-butylphthalate (DBP), butyl-benzyl-phthalate (BBP), bis(2-ethylhexyl)phthalate (DEHP), di-isononylphthalate (DINP) and di-isodecylphthalate (DIDP) for use in food contact materials

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP Panel) was asked by the European Commission to update its 2005 risk assessments of di‐butylphthalate (DBP), butyl‐benzyl‐phthalate (BBP), bis(2‐ethylhexyl)phthalate (DEHP), di‐isononylphthalate (DINP) and di‐isodecylphthalate (DIDP), which are authorised for use in plastic food contact material (FCM). Dietary exposure estimates (mean and high (P95)) were obtained by combining literature occurrence data with consumption data from the EFSA Comprehensive Database. The highest exposure was found for DINP, ranging from 0.2 to 4.3 and from 0.4 to 7.0 μg/kg body weight (bw) per day for mean and high consumers, respectively. There was not enough information to draw conclusions on how much migration from plastic FCM contributes to dietary exposure to phthalates. The review of the toxicological data focused mainly on reproductive effects. The CEP Panel derived the same critical effects and individual tolerable daily intakes (TDIs) (mg/kg bw per day) as in 2005 for all the phthalates, i.e. reproductive effects for DBP (0.01), BBP (0.5), DEHP (0.05), and liver effects for DINP and DIDP (0.15 each). Based on a plausible common mechanism (i.e. reduction in fetal testosterone) underlying the reproductive effects of DEHP, DBP and BBP, the Panel considered it appropriate to establish a group‐TDI for these phthalates, taking DEHP as index compound as a basis for introducing relative potency factors. The Panel noted that DINP also affected fetal testosterone levels at doses around threefold higher than liver effects and therefore considered it conservative to include it within the group‐TDI which was established to be 50 μg/kg bw per day, expressed as DEHP equivalents. The aggregated dietary exposure for DBP, BBP, DEHP and DINP was estimated to be 0.9–7.2 and 1.6–11.7 μg/kg bw per day for mean and high consumers, respectively, thus contributing up to 23% of the group‐TDI in the worst‐case scenario. For DIDP, not included in the group‐TDI, dietary exposure was estimated to be always below 0.1 μg/kg bw per day and therefore far below the TDI of 150 μg/kg bw per day. This assessment covers European consumers of any age, including the most sensitive groups. Based on the limited scope of the mandate and the uncertainties identified, the Panel considered that the current assessment of the five phthalates, individually and collectively, should be on a temporary basis.

This publication is linked to the following EFSA Supporting Publications article: http://onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2019.EN-1747/full

In utero exposure to persistent and nonpersistent endocrine-disrupting chemicals and anogenital distance. A systematic review of epidemiological studies†

Anti-androgenic endocrine-disrupting chemicals (EDCs) can cross the placenta to modify early offspring sexual dimorphic markers. These changes are linked to anogenital distance (AGD), which is an androgen-sensitive anthropometric parameter used as a biomarker of perineal growth and caudal migration of the genital tubercle. This review aimed to summarize strength of evidence for associations of in utero exposure to EDCs with AGD and to identify gaps and limitations in the literature so as to inform future research. We performed an electronic search of English literature in September 2019 in medical literature analysis and retrieval system online (MEDLINE), Web of Science and Toxline. We included epidemiological studies that examined in utero exposure to persistent and nonpersistent EDCs and considered AGD in offspring as an outcome. Our review contained 16 investigations examining exposure to persistent EDCs (nine studies) and nonpersistent EDCs (seven studies). Some individual studies reported an inverse association between exposure to bisphenol A (BPA), dioxins, perfluoroalkyl substances, and organochlorides and AGD in both male and female offspring. Meta-analysis of three studies found a small reduction of AGD in female offspring exposed to BPA. The number of studies per chemical is small, and number of subjects examined is limited; so, replication of these results is needed. To achieve more specificity and better replication of results, future studies should establish the association of nonpersistent EDCs using multiple urine samples, evaluate the cumulative impact of exposure to a mixture of anti-androgenic chemicals, and offer adequate consideration of more maternal- and children-related confounding factors.

Do stressful life events during pregnancy modify associations between phthalates and anogenital distance in newborns?

Anogenital distance (AGD) has been used as a marker of fetal androgen action to identify endocrine disrupting chemicals. A US study (TIDES) has reported that the association between some phthalates and reduced AGD in males was only apparent in sons of mothers reporting no stressful life events (SLEs) during pregnancy. The objective of the current study was to examine the potential modifying effect of SLEs and their subjective impact on associations between prenatal phthalates and AGD. First trimester urines from the MIREC Study were analysed for phthalate metabolites and AGD was measured in neonates. Post-delivery, the women answered questions on SLEs during the pregnancy. Women reporting 1 or more SLEs during pregnancy were considered a "higher stressor" group, whereas women reporting no SLEs or who reported a SLE that was perceived as not at all stressful were considered a "lower stressor" group. Multivariable linear regression models were fit stratified by stressor group. Maternal stressor, AGD and phthalates results were available for 153 females and 147 males. A summary measure of androgen-disrupting phthalates (Σ AD) was associated with significantly longer AGDs in females from the higher stressor group. These effect sizes were increased when the perceived impact was restricted to moderately or very much stressful. In males, all phthalates were associated with longer anopenile distance (APD), regardless of stressor group; however, higher Σ AD was associated with significantly longer APD in the lower stressor group. In contrast to the TIDES study, we did not observe shorter AGDs in male infants prenatally exposed to di-(2-ethylhexyl) phthalates, regardless of maternal stressor level. In conclusion, we were unable to replicate the findings of the TIDES study, but did find some evidence that prenatal SLEs may modify associations between phthalates and female AGD. Further research with other populations and measures of prenatal stress may shed more light on whether prenatal stress is an important effect modifier of associations between phthalates (or other chemicals) and anogenital distance.

Genetic resistance to DEHP-induced transgenerational endocrine disruption

Di(2-ethylhexyl)phthalate (DEHP) interferes with sex hormones signaling pathways (SHP). C57BL/6J mice prenatally exposed to 300 mg/kg/day DEHP develop a testicular dysgenesis syndrome (TDS) at adulthood, but similarly-exposed FVB/N mice are not affected. Here we aim to understand the reasons behind this drastic difference that should depend on the genome of the strain. In both backgrounds, pregnant female mice received per os either DEHP or corn oil vehicle and the male filiations were examined. Computer-assisted sperm analysis showed a DEHP-induced decreased sperm count and velocities in C57BL/6J. Sperm RNA sequencing experiments resulted in the identification of the 62 most differentially expressed RNAs. These RNAs, mainly regulated by hormones, produced strain-specific transcriptional responses to prenatal exposure to DEHP; a pool of RNAs was increased in FVB, another pool of RNAs was decreased in C57BL/6J. In FVB/N, analysis of non-synonymous single nucleotide polymorphisms (SNP) impacting SHP identified rs387782768 and rs29315913 respectively associated with absence of the Forkhead Box A3 (Foxa3) RNA and increased expression of estrogen receptor 1 variant 4 (NM_001302533) RNA. Analysis of the role of SNPs modifying SHP binding sites in function of strain-specific responses to DEHP revealed a DEHP-resistance allele in FVB/N containing an additional FOXA1-3 binding site at rs30973633 and four DEHP-induced beta-defensins (Defb42, Defb30, Defb47 and Defb48). A DEHP-susceptibility allele in C57BL/6J contained five SNPs (rs28279710, rs32977910, rs46648903, rs46677594 and rs48287999) affecting SHP and six genes (Svs2, Svs3b, Svs4, Svs3a, Svs6 and Svs5) epigenetically silenced by DEHP. Finally, targeted experiments confirmed increased methylation in the Svs3ab promoter with decreased SEMG2 persisting across generations, providing a molecular explanation for the transgenerational sperm velocity decrease found in C57BL/6J after DEHP exposure. We conclude that the existence of SNP-dependent mechanisms in FVB/N inbred mice may confer resistance to transgenerational endocrine disruption.

The structure-activity relationship (SAR) for phthalate-mediated developmental and reproductive toxicity in males

Testicular dysgenesis syndrome includes the hypospadias, cryptorchidism and abnormal fetal testis in male neonate. This is possibly caused by the environmental phthalates, which down-regulate the expression of androgen synthetic genes and Insl3 or directly inhibits steroidogenic enzymes. There are distinct structure-activity relationships (SARs) for phthalate-mediated developmental and reproductive toxicity. Here, we review the SAR for phthalate-mediated testicular dysgenesis syndrome. Of phthalates of straight side chains, C5-C6 ones are the most potent, C4 or C7 are moderate, C3 is weakest, and C1-2 or C8-13 are ineffective. The branching and unsaturation of side chains increases the toxicity. The cycling of side chains does not increase the toxicity.

Risk assessment of phthalates in pharmaceuticals

Phthalates are used for industrial plasticizers to impart flexibility and durability to polyvinyl chloride. Despite widespread use of phthalates, reported endocrine-disrupting properties raise safety concerns for consumers. Since phthalates are permitted as excipients in controlled-release capsules and enteric coatings, patients taking drugs containing these chemicals may potentially be at some health risk. In this study, 102 distinct pharmaceutical products were analyzed by gas chromatography/mass spectrometry to determine phthalate content and maximal phthalate exposure rate was calculated. In 102 drug samples, di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), and diethyl phthalate (DEP) were detected in 9.8, 27.45, and 5.88% of cases, respectively. The highest level of DEP was found in extended-release (ER) capsules with concentrations ranging from 935.5 to 1535.37 ppb. The highest levels of DBP (1.32-7.07 ppb) were detected in tablets, whereas highest level (7.07 ppb) of DEHP was found in suspension preparations. The phthalate hazard index (HI) (human exposure tolerable daily intake) was calculated for each sample, but no sample exhibited an HI value exceeding 1; the minimum value taken to indicate a serious health risk. Thus, no apparent serious health risk from phthalate exposure arises from taking these medications. The low HI values suggest that phthalate contamination in pharmaceuticals may not pose an apparent significant risk to humans. However, the sources of phthalate present in pharmaceutical products still needs to be investigated and verified through on-site inspections in manufacturing processes in order to minimize human exposure. It is recommended that measures be taken to prevent phthalate contamination in pharmaceuticals.

The role of exposure to phthalates in variations of anogenital distance: A systematic review and meta-analysis

Environmental chemicals such as phthalate esters may have adverse effects on anogenital distance (AGD), but the evidence in both genders has not been reviewed systematically. The objective of the present study is to conduct a systematic review and meta-analysis of studies that analyzed the relationship between exposure to phthalates and AGD. English papers published up to March 2018 were searched in PubMed, Scopus, Clarivate-Web of Science, and Google scholar. We applied fixed-effects models to calculate pooled beta coefficient [β]. In the case of heterogeneity, random-effects models were used. Using the comprehensive search strategies, 313 papers were identified and after screening, 10 of them were included in this study. In primary analyses, we found that exposure to phthalates was not associated with short AGD (β = -0.11; 95% CI, -0.27, 0.06; I2 = 0%). However, results of subgroup analyses indicated that in boys, the sum of di-2-ethylhexyl phthalate (∑DEHP) metabolites had significant association with the risk of shortened anopenile distance (AGDAP) (β = -0.915, 95% CI: 1.629, -0.2) and anoscrotal distance (AGDAS) (β = -0.857, 95% CI: 1.455, -0.26). In addition, urinary monobutyl phthalate (MBP), monoethyl phthalate (MEP), and monoisobutyl phthalate (MiBP) were associated with short AGDAP. We also observed significant association between monobenzylphthalate (MBzP) and anofourchette distance (AGDAF) in girls. Our study provided findings on significant association of exposure to ∑DEHP metabolites, MBP, MEP, and MiBP with shortened AGDAP in boys. The mechanisms of phthalates effect on AGD may involve receptors and enzymes involved in steroidgenesis, negative influence on Leydig cells, cell proliferation, gonocyte cell numbers, and testosterone production.

Pregnancy phthalate metabolite concentrations and infant birth weight by gradations of maternal glucose tolerance

BACKGROUND

Higher birth weight is an important adverse outcome associated with hyperglycemia in pregnancy. Recent studies suggest that phthalate exposure is associated with elevated glucose levels in pregnant women, with implications for higher birth weight in the offspring. No study to date has investigated the association between prenatal phthalate exposure on infant high birth weight accounting for the range of pregnancy glucose levels.

METHODS

A total of 350 women participating in an ongoing pregnancy cohort had data available on urinary phthalate metabolite concentrations at up to four time points across pregnancy. Urinary phthalate metabolites were averaged across pregnancy and log-transformed, specific gravity-adjusted and analyzed in quartiles. Birth weight was examined continuously (in grams), as well as dichotomized as large for gestational age (>90^th percentile). Glucose levels were assessed based on Results from 50-g glucose challenge tests as a part of screening for gestational diabetes conducted at 24-28 weeks gestation, and grouped into 3 categories <120 mg/dL, 120-<140 mg/dL and ≥140 mg/dL. Multivariable linear regression was performed, adjusting for potential confounders in the overall population and stratified by pregnancy glucose levels.

RESULTS

Approximately 20% of infants born to women with glucose levels ≥140 mg/dL were large for gestational age. Average mono-ethyl phthalate (MEP) concentrations were higher among women who had glucose levels ≥140 mg/dL (geometric mean 140.9 μg/L; 95% CI: 91.6-216.8); however, higher MEP concentrations were not associated with higher birth weight. When stratified by maternal glucose levels, there was a suggestive association between higher concentrations of mono-(3-carboxypropyl) phthalate (MCPP) and higher birth weight among women with glucose levels ≥140 mg/dL (adj. birth weight: 569.2 g; 95% CI: 14.1, 1178.2).

CONCLUSIONS

Higher urinary phthalate metabolite concentrations were not significantly associated with higher birth weight. Counter to our hypothesis, women with higher glucose levels and higher urinary phthalate metabolites did not deliver babies with higher birth weight.