Medications as a potential source of exposure to phthalates in the U.S. population

Single-cell RNA-seq reveals that granulosa cells are a target of phthalate toxicity in the ovary

Phthalates are known endocrine-disrupting chemicals and ovarian toxicants that are used widely in consumer products. Phthalates have been shown to exert ovarian toxicity on multiple endpoints, altering transcription of genes responsible for normal ovarian function. However, the molecular mechanisms by which phthalates act on the ovary are not well understood. In this study, we hypothesized that phthalates specifically target granulosa cells within the ovarian follicle. To test our hypothesis, we cultured whole mouse antral follicles for 96 h in the presence of vehicle or 10 µg/ml of a phthalate metabolite mixture. At the end of the culture period, follicles were dissociated into single-cell suspensions and subjected to single-cell RNA-sequencing. We used markers from published studies to identify cell-type clusters, the largest of which were granulosa and theca/stroma cells. We further identified subpopulations of granulosa, theca, and stromal cells and analyzed differentially expressed genes between the phthalate treatment and control. Granulosa cells, specifically mural granulosa cells, had the most differentially expressed genes. Pathway analysis of differentially expressed genes from the overall granulosa cell cluster revealed disruption of cell cycle and mitosis, whereas pathway analysis of the mural granulosa cell subcluster identified terms related to translation, ribosome, and endoplasmic reticulum. Our findings suggest that phthalates have both broad impacts on cell types and specific impacts on cellular subtypes, emphasizing the complexity of phthalate toxicity and highlighting how bulk sequencing can mask effects on vulnerable cell types.

The role of plastics in allergy, immunology, and human health: What the clinician needs to know and can do about it

The effects of plastics on human health include allergy, atopy, asthma, and immune disruption, but the consequences of chemicals used in plastic materials span nearly every organ system and age group as well. Behavioral interventions to reduce plastic chemical exposures have reduced exposure in low- and high-income populations, yet health care providers know little about plastic chemical effects and seldom offer steps to patients to limit exposure. Health care facilities also use many products that increase the risk of chemical exposures, particularly for at-risk populations such as children in neonatal intensive care units. Given that disparities in plastic chemical exposure are well documented, collaborative efforts are needed between scientists and health care organizations, to develop products that improve provider knowledge about chemicals used in plastic materials and support the use of safer alternatives in medical devices and other equipment.

Mixtures of phthalates disrupt expression of genes related to lipid metabolism and peroxisome proliferator-activated receptor signaling in mouse granulosa cells

Phthalates are a class of known endocrine-disrupting chemicals that are found in common everyday products. Several studies associate phthalate exposure with detrimental effects on ovarian function, including growth and development of the follicle and production of steroid hormones. We hypothesized that dysregulation of the ovary by phthalates may be mediated by phthalate toxicity towards granulosa cells, a major cell type in ovarian follicles responsible for key steps of hormone production and nourishing the developing oocyte. To test the hypothesis that phthalates target granulosa cells, we harvested granulosa cells from adult CD-1 mouse ovaries and cultured them for 96 h in vehicle control, a phthalate mixture, or a phthalate metabolite mixture (0.1 to 100 μg/ml). After culture, we measured metabolism of the phthalate mixture into monoester metabolites by the granulosa cells, finding that granulosa cells do not significantly contribute to ovarian metabolism of phthalates. Immunohistochemistry of phthalate metabolizing enzymes in whole ovaries confirmed that these enzymes are not strongly expressed in granulosa cells of antral follicles and that ovarian metabolism of phthalates likely occurs primarily in the stroma. RNA sequencing of treated granulosa cells identified 407 differentially expressed genes, with overrepresentation of genes from lipid metabolic processes, cholesterol metabolism, and peroxisome proliferator-activated receptor (PPAR) signaling pathways. Expression of significantly differentially expressed genes related to these pathways was confirmed using qPCR. Our results agree with previous findings that phthalates and phthalate metabolites have different effects on the ovary, but both interfere with PPAR signaling in granulosa cells.

Endocrine disruption and male reproductive disorders: unanswered questions

Maternal exposure to endocrine-disrupting chemicals (EDCs) in human pregnancy is widely considered as an important cause of adverse changes in male reproductive health due to impaired foetal androgen production/action. However, the epidemiological evidence supporting this view is equivocal, except for certain phthalates, notably diethyl hexyl phthalate (DEHP). Maternal phthalate exposure levels associated with adverse reproductive changes in epidemiological studies are several thousand-fold lower than those needed to suppress foetal androgen production in rats, and direct studies using human foetal testis tissue show no effect of high phthalate exposure on androgen production. This conundrum is unexplained and raises fundamental questions. Human DEHP exposure is predominantly via food with highest exposure associated with consumption of a Western style (unhealthy) diet. This diet is also associated with increased exposure to the most common EDCs, whether persistent (chlorinated or fluorinated chemicals) or non-persistent (phthalates, bisphenols) compounds, which are found at highest levels in fatty and processed foods. Consequently, epidemiological studies associating EDC exposure and male reproductive health disorders are confounded by potential dietary effects, and vice versa. A Western diet/lifestyle in young adulthood is also associated with low sperm counts. Disentangling EDC and dietary effects in epidemiological studies is challenging. In pregnancy, a Western diet, EDC exposure, and maternal living in proximity to industrial sites are all associated with impaired foetal growth/development due to placental dysfunction, which predisposes to congenital male reproductive disorders (cryptorchidism, hypospadias). While the latter are considered to reflect impaired foetal androgen production, effects resulting from foetal growth impairment (FGI) are likely indirect. As FGI has numerous life-long health consequences, and is affected by maternal lifestyle, research into the origins of male reproductive disorders should take more account of this. Additionally, potential effects on foetal growth/foetal testis from the increasing use of medications in pregnancy deserves more research attention.

The Dual Faces of Oestrogen: The Impact of Exogenous Oestrogen on the Physiological and Pathophysiological Functions of Tissues and Organs

Oestrogen plays a crucial physiological role in both women and men. It regulates reproductive functions and maintains various non-reproductive tissues through its receptors, such as oestrogen receptor 1/oestrogen receptor α (ESR1/Erα), oestrogen receptor 2/oestrogen receptor β (ESR2/Erβ), and G protein-coupled oestrogen receptor 1 (GPER). This hormone is essential for the proper functioning of women's ovaries and uterus. Oestrogen supports testicular function and spermatogenesis in men and contributes to bone density, cardiovascular health, and metabolic processes in both sexes. Nuclear receptors Er-α and Er-β belong to the group of transcription activators that stimulate cell proliferation. In the environment, compounds similar in structure to the oestrogens compete with endogenous hormones for binding sites to receptors and to disrupt homeostasis. The lack of balance in oestrogen levels can lead to infertility, cancer, immunological disorders, and other conditions. Exogenous endocrine-active compounds, such as bisphenol A (BPA), phthalates, and organic phosphoric acid esters, can disrupt signalling pathways responsible for cell division and apoptosis processes. The metabolism of oestrogen and its structurally similar compounds can produce carcinogenic substances. It can also stimulate the growth of cancer cells by regulating genes crucial for cell proliferation and cell cycle progression, with long-term elevated levels linked to hormone-dependent cancers such as breast cancer. Oestrogens can also affect markers of immunological activation and contribute to the development of autoimmune diseases. Hormone replacement therapy, oral contraception, in vitro fertilisation stimulation, and hormonal stimulation of transgender people can increase the risk of breast cancer. Cortisol, similar in structure to oestrogen, can serve as a biomarker associated with the risk of developing breast cancer. The aim of this review is to analyse the sources of oestrogens and their effects on the endogenous and exogenous process of homeostasis.

Mixtures of phthalates disrupt expression of genes related to lipid metabolism and peroxisome proliferator-activated receptor signaling in mouse granulosa cells

Phthalates are a class of known endocrine disrupting chemicals that are found in common everyday products. Several studies associate phthalate exposure with detrimental effects on ovarian functions, including growth and development of the follicle and production of steroid hormones. We hypothesized that dysregulation of the ovary by phthalates may be mediated by phthalate toxicity towards granulosa cells, a major cell type in ovarian follicles responsible for key steps of hormone production and nourishing the developing oocyte. To test the hypothesis that phthalates target granulosa cells, we harvested granulosa cells from adult CD-1 mouse ovaries and cultured them for 96 hours in vehicle control, a phthalate mixture, or a phthalate metabolite mixture (0.1-100 μg/mL). After culture, we measured metabolism of the phthalate mixture into monoester metabolites by the granulosa cells, finding that granulosa cells do not significantly contribute to ovarian metabolism of phthalates. Immunohistochemistry of phthalate metabolizing enzymes in whole ovaries confirmed that these enzymes are not strongly expressed in granulosa cells of antral follicles and that ovarian metabolism of phthalates likely occurs primarily in the stroma. RNA sequencing of treated granulosa cells identified 407 differentially expressed genes, with overrepresentation of genes from lipid metabolic processes, cholesterol metabolism, and peroxisome proliferator-activated receptor (PPAR) signaling pathways. Expression of significantly differentially expressed genes related to these pathways were confirmed using qPCR. Our results agree with previous findings that phthalates and phthalate metabolites have different effects on the ovary and interfere with PPAR signaling in granulosa cells.

Exploring the relationship between urinary phthalate metabolites and Crohn's disease via oxidative stress, and the potential moderating role of gut microbiota: A conditional mediation model

OBJECTIVE

Interactions between phthalic acid esters (PAEs) exposure and Crohn's disease (CD) were unknown. This study aims to examine the association between exposure to PAEs and CD activity and to explore the roles of oxidative stress and microbiota.

METHODS

A cross-sectional study with 127 CD patients was conducted. The disease activity was evaluated based on symptoms (Harvey-Bradshaw index, HBI), endoscopy findings (Simple Endoscopic Score for CD, SES-CD), and computed tomography enterography (CTE-scores). Ten urinary PAEs metabolites (mPAEs), two urinary oxidative stress biomarkers, including 8-hydroxydeoxyguanosine (8-OHdG) and 8-iso-prostaglandin-F2α (8-iso-PGF2α), as well as 16S rRNA sequencing of stool samples were determined. Multiple linear regression models and Hayes's PROCESS macro for SPSS were used to evaluate the interplays between urinary PAEs metabolites, CD activities, oxidative stress, and microbiota diversity.

RESULTS

There were positive associations between most mPAEs and HBI. Oxidative stress mediated 20.69-89.29% of the indirect associations between low molecular weight (LMW) mPAEs and HBI, while the majority of the high molecular weight (HMW) mPAEs were directly associated with HBI. In addition, microbiota diversity moderated the indirect associations of LMW mPAEs on HBI.

CONCLUSIONS

PAEs exposure was related to CD activity, and the association could be mediated by oxidative stress and reversed or alleviated by rich gut microbiota.

Exposure to a phthalate mixture disrupts ovulatory progesterone receptor signaling in human granulosa cells in vitro†

Exposure to phthalates disrupts ovarian function. However, limited studies have investigated the effects of phthalate mixtures on ovulation, especially in women. Human granulosa cells were used to test the hypothesis that exposure to a phthalate mixture (PHTmix) disrupts progesterone (P4)/progesterone receptor (PGR) signaling, which is a crucial pathway for ovulation. In addition, progestin and cyclic adenosine 3', 5'-monophosphate (cAMP) supplementation were tested as methods to circumvent phthalate toxicity. Granulosa cells from women undergoing in vitro fertilization were acclimated in culture to regain responsiveness to human chorionic gonadotropin (hCG; clinical luteinizing hormone analogue). Granulosa cells were treated with or without hCG, and with or without PHTmix (1-500 μg/ml; dimethylsulfoxide = vehicle control) for 0.5-36 h. In the supplementation experiments, cells were treated with or without R5020 (stable progestin), and with or without 8-Br-cAMP (stable cAMP analogue). Exposure to hCG + PHTmix decreased P4 levels and mRNA levels of steroidogenic factors when compared to hCG. This was accompanied by decreased mRNA levels of PGR and downstream P4/PGR ovulatory mediators (ADAM metallopeptidase with thrombospondin type 1 motif 1 (ADAMTS1), C-X-C motif chemokine receptor 4 (CXCR4), pentraxin 3 (PTX3), and regulator of G protein signaling 2 (RGS2)) in the hCG + PHTmix groups compared to hCG. Exposure to hCG + PHTmix 500 μg/ml decreased cAMP levels and protein kinase A activity compared to hCG. Supplementation with progestin in the hCG + PHTmix 500 μg/ml group did not rescue toxicity, while supplementation with cAMP restored PGR levels and downstream P4/PGR mediator levels to hCG levels. These findings suggest that phthalate mixture exposure inhibits P4/PGR signaling in human granulosa cells via decreased steroidogenesis, cAMP levels, and protein kinase A activity. Restored P4/PGR signaling with cAMP supplementation provides a potential cellular target for intervention of phthalate-induced ovulatory dysfunction in women.

Early-Life Exposure to a Mixture of Phenols and Phthalates in Relation to Child Social Behavior: Applying an Evidence-Based Prioritization to a Cohort with Improved Exposure Assessment

BACKGROUND

Previous studies aiming at relating exposure to phenols and phthalates with child social behavior characterized exposure using one or a few spot urine samples, resulting in substantial exposure misclassification. Moreover, early infancy exposure was rarely studied.

OBJECTIVES

We aimed to examine the associations of phthalates and phenols with child social behavior in a cohort with improved exposure assessment and to a priori identify the chemicals supported by a higher weight of evidence.

METHODS

Among 406 mother-child pairs from the French Assessment of Air Pollution exposure during Pregnancy and Effect on Health (SEPAGES) cohort, 25 phenols/phthalate metabolites were measured in within-subject pools of repeated urine samples collected at the second and third pregnancy trimesters (∼ 21 samples/trimester) and at 2 months and 1-year of age (∼ 7 samples/period). Social behavior was parent-reported at 3 years of age of the child using the Social Responsiveness Scale (SRS). A structured literature review of the animal and human evidence was performed to prioritize the measured phthalates/phenols based on their likelihood to affect social behavior. Both adjusted linear regression and Bayesian Weighted Quantile Sum (BWQS) regression models were fitted. False discovery rate (FDR) correction was applied only to nonprioritized chemicals.

RESULTS

Prioritized compounds included bisphenol A, bisphenol S, triclosan (TCS), diethyl-hexyl phthalate (Σ DEHP ), mono-ethyl phthalate (MEP), mono-n -butyl phthalate (MnBP), and mono-benzyl phthalate (MBzP). With the exception of bisphenols, which showed a mixed pattern of positive and negative associations in pregnant mothers and neonates, few prenatal associations were observed. Most associations were observed with prioritized chemicals measured in 1-y-old infants: Each doubling in urinary TCS (β = 0.78 ; 95% CI: 0.00, 1.55) and MEP (β = 0.92 ; 95% CI: - 0.11 , 1.96) concentrations were associated with worse total SRS scores, whereas MnBP and Σ DEHP were associated with worse Social Awareness (β = 0.25 ; 95% CI: 0.01, 0.50) and Social Communication (β = 0.43 ; 95% CI: - 0.02 , 0.89) scores, respectively. BWQS also suggested worse total SRS [Beta  1 = 1.38 ; 95% credible interval (CrI): - 0.18 , 2.97], Social Awareness (Beta  1 = 0.37 ; 95% CrI: 0.06, 0.70), and Social Communication (Beta  1 = 0.91 ; 95% CrI: 0.31, 1.53) scores per quartile increase in the mixture of prioritized compounds assessed in 1-y-old infants. The few associations observed with nonprioritized chemicals did not remain after FDR correction, with the exception of benzophenone-3 exposure in 1-y-old infants, which was suggestively associated with worse Social Communication scores (corrected p = 0.07 ).

DISCUSSION

The literature search allowed us to adapt our statistical analysis according to the weight of evidence and create a corpus of experimental and epidemiological knowledge to better interpret our findings. Early infancy appears to be a sensitive exposure window that should be further investigated. https://doi.org/10.1289/EHP11798.

Low-dose phthalates promote breast cancer stem cell properties via the oncogene ΔNp63α and the Sonic hedgehog pathway

BACKGROUND

The omnipresence of human phthalate (PAE) exposure is linked to various adverse health issues, including breast cancer. However, the effects of low-dose PAE exposure on breast cancer stem cells (BCSCs) and the underlying mechanism remain unexplored.

METHODS

BCSCs from breast cancer cell lines (MDA-MB-231 and MCF-7) were enriched using a tumorsphere formation assay. Gene and protein expression was detected by measurement of quantitative real-time reverse transcription PCR, western blot, and immunofluorescence assays. Transient transfection assays were used to evaluate the involvement of Gli1, a signaling pathway molecule and ΔNp63α, an oncogene in influencing the PAE-induced characteristics of BCSCs.

RESULTS

PAE (butylbenzyl phthalate, BBP; di-butyl phthalate, DBP; di-2-ethylhexyl phthalate, DEHP) exposure of 10^-9 M significantly promoted the tumorsphere formation ability in BCSCs. Breast cancer spheroids with a 10^-9 M PAE exposure had higher levels of BCSC marker mRNA and protein expression, activated sonic hedgehog (SHH) pathway, and increased mRNA and protein levels of an oncogene, ΔNp63α. Furthermore, suppression of the SHH pathway attenuated the effects of PAEs on BCSCs. And the overexpression of ΔNp63α enhanced PAE-induced characteristics of BCSCs, while low expression of ΔNp63α inhibited the promotion effects of PAEs on BCSCs and the SHH pathway.

CONCLUSION

Low-dose PAE exposure promoted the stem cell properties of BCSCs in a ΔNp63α- and SHH-dependent manner. The influence of low-dose exposure of PAEs and its relevance for the lowest observed effect concentrations requires further investigation, and the precise underlying mechanism needs to be further explored.

Pregnancy in Patients with Inflammatory Bowel Diseases-A Literature Review

In recent years, we have faced an increasing incidence of inflammatory bowel disease (IBD), especially among young people, affecting them during their reproductive years. The paucity of data and reduced knowledge regarding the evolution of the disease during pregnancy and the adverse effects of the therapy on the mother and infant increase voluntary childlessness in this group of patients. Depending on the type of IBD, severity and surgical or medical management, this can negatively affect the pregnancy. C-sections and the risk of low-birth-weight babies are higher in women with IBD, independent of active/inactive disease, while preterm birth, stillbirth and miscarriage are associated with disease activity. In the last period, medicinal therapy has evolved, and new molecules have been developed for better control of the lesions, but the effect on pregnancy and breastfeeding is still controversial. We conducted this review by studying the literature and recent research in order to have a better image of the practical management of IBD during pregnancy.

Phthalates impact on the epigenetic factors contributed specifically by the father at fertilization

BACKGROUND

Preconception exposure to phthalates such as the anti-androgenic dibutyl-phthalate (DBP) impacts both male and female reproduction, yet how this occurs largely remains unknown. Previously we defined a series of RNAs expressly provided by sperm at fertilization and separately, and in parallel, those that responded to high DBP exposure. Utilizing both populations of RNAs, we now begin to unravel the impact of high-DBP exposure on those RNAs specifically delivered by the father.

RESULTS

Enrichment of RNAs altered by DBP exposure within the Molecular Signature Database highlighted cellular stress, cell cycle, apoptosis, DNA damage response, and gene regulation pathways. Overlap within each of these five pathways identified those RNAs that were specifically (≥ fivefold enriched) or primarily (≥ twofold enriched) provided as part of the paternal contribution compared to the oocyte at fertilization. Key RNAs consistently altered by DBP, including CAMTA2 and PSME4, were delivered by sperm reflective of these pathways. The majority (64/103) of overlapping enriched gene sets were related to gene regulation. Many of these RNAs (45 RNAs) corresponded to key interconnected CRREWs (Chromatin remodeler cofactors, RNA interactors, Readers, Erasers, and Writers). Modeling suggests that CUL2, PHF10, and SMARCC1 may coordinate and mechanistically modulate the phthalate response.

CONCLUSIONS

Mediated through a CRREW regulatory network, the cell responded to exposure presenting stressed-induced changes in the cell cycle-DNA damage-apoptosis. Interestingly, the majority of these DBP-responsive epigenetic mediators' direct acetylation or deacetylation, impacting the sperm's cargo delivered at fertilization and that of the embryo.

Quantitative Measurement of Phthalate Exposure Biomarker Levels in Diaper-Extracted Urine of Japanese Toddlers and Cumulative Risk Assessment: An Adjunct Study of JECS Birth Cohort

Phthalate exposure monitoring and risk assessment in non-toilet-trained children are rarely reported. This adjunct study of the Japan Environment and Children's Study assessed cumulative health risks in 1.5-year-old toddlers in the Aichi regional subcohort by biomonitoring 16 urinary metabolites of eight phthalate plasticizers. Overnight urine was extracted from toddlers' diapers (n = 1077), and metabolites were quantified using ultraperformance liquid chromatography coupled with tandem mass spectrometry. The analyses' quality was assured by running quality control samples. The highest geometric mean concentration was found for mono-(2-ethyl-5-carboxypentyl) phthalate, followed by mono-isobutyl phthalate (23 and 21 μg/L, respectively). Di-2-ethylhexyl phthalate (DEHP) and di-butyl phthalate exhibited higher risks [hazard quotient (HQ) > 1] than the cutoff level in a small proportion of toddlers; 8 and 14% of toddlers were at cumulative risk of multiple phthalates beyond the cutoff level [hazard index, (HI) > 1], based on the tolerable daily intake of the European Food Safety Authority and the United States Environmental Protection Agency Reference Dose. HI > 1 for antiandrogenicity in creatinine-unadjusted and -adjusted estimations were exhibited by 36 and 23% of the children, respectively. Thus, identifying exposure sources and mitigating exposure are necessary for risk management. Additionally, continuous exposure assessment and evaluation of health outcomes, especially antiandrogenic effects, are warranted.

Effect of di(n-butyl) phthalate on the blood-testis barrier during puberty onset

Di(n-butyl) phthalate (DBP) is considered a substance of serious concern because of its reproductive toxicity and endocrine-disrupting properties. Exposure to DBP causes morphological and functional changes in the male reproductive system of birds and mammals. However, there are no detailed reports on the effects of DBP on the Sertoli cell and junctional complexes of the blood-testis barrier (BTB) in birds. The present study investigated dose-related ultrastructural changes in Sertoli cells and junctional complexes of the BTB in adult Japanese quail (Coturnix coturnix japonica) exposed to DBP prior to puberty. A total of 25 Japanese quail were used for the study. Exposure to DBP doses of 50, 200 and 400 mg DBP/kg/d caused dose-related ultrastructural changes in junctional complexes including dilation and separation, while disruption of cytoplasmic membranes and mitochondria was observed in Sertoli cells. There was a significant difference in the sum of vacuoles, vacuole diameter, nuclear width, nuclear length, nuclear area, sum of damaged spherical mitochondria, width of elongated mitochondria and the sum of damaged elongated mitochondria among the five treatment groups (p ˂ 0.05). Prepubertal exposure to DBP at doses of 50, 200 and 400 mg DBP/kg/d for 30 days led to adverse effects in the adult male Japanese quail reproductive system by inducing structural changes in the Sertoli cells and junctional complexes. Such changes might disrupt the BTB and potentially interfere with spermatogenesis. Results indicated that the Sertoli cell is sensitive to DBP exposure and might be an important cellular target for DBP-induced testicular toxicity.

A Practical Approach to IBD Care in the Pregnant Patient

PURPOSE OF REVIEW

As the incidence of inflammatory bowel disease (IBD) rises, gastroenterologists are more commonly facing management of the disease in women of childbearing age. This coincides with the development of new IBD therapies whose use in pregnancy must be considered.

RECENT FINDINGS

This review provides updated recommendations for newer biologic agents and small molecules that have been approved for IBD treatment since the previous guidelines were published. In addition, recent research has found that prior IBD-related surgeries, not just ileal pouch-anal anastomosis, can impact pregnancy outcomes. Reassuringly, assisted reproductive technology for IBD patients has been found to have similar success rates to the non-IBD population. Ensuring disease remission prior to conception and throughout pregnancy is key for optimizing pregnancy and fetal outcomes. As gastroenterologists play an integral role in the management of IBD throughout the peripartum period, this review summarizes recent studies in combination with existing guidelines to address preconception counseling, medication safety, and management for quiescent and active disease throughout pregnancy.

Simple ultrasensitive electrochemical detection of the DBP plasticizer for the risk assessment of South Korean river waters

Rapid detection of contaminants for the purpose of sensitive and quantitative monitoring of environmental hazards is an essential first step in realizing the avoidance of human health risks. In this regard, we present a fast and simple electrochemical method of detecting di-n-butyl phthalate (DBP) from river water samples using a phthalic acid group specific aptamer modified on a gold nanoparticle (AuNP) functionalized graphene oxide nano-platelet (GO) and ionic liquid (IL) nanocomposite. Here, the IL/GO nanocomposite allows an enhanced interaction with phthalate esters, thereby increasing the sensitivity of the sensor surface. The proposed sensor showed a wide linear dynamic range from 0.14 pg mL^-1 to 0.35 ng mL^-1 and from 0.35 ng mL^-1 to 7 ng mL^-1 with a detection limit of ≤0.042 pg mL^-1, which were evaluated using standard, analytical grade DBP; the limit of quantification was determined using different concentrations of DBP in DI water in comparison with gas chromatography-mass spectroscopy (GC/MS) values. The proposed sensor was used to monitor the DBP concentrations in river water samples collected from various locations across South Korea. The quantitative data from the measurements in comparison with standard GC/MS values were then used to ascertain the human health risk posed by the daily consumption of these river waters.

Maternal DBP exposure promotes synaptic formation in offspring by activating astrocytes via the AKT/NF-κB/IL-6/JAK2/STAT3 signaling pathway

It has been demonstrated that activated astrocytes in the hypothalamus could disrupt GnRH secretion in offspring after maternal di-n-butyl phthalate (DBP) exposure, indicating that the effect of DBP on astrocyte activation and crosstalk between astrocytes and neurons is still worthy of further investigation. In this study, pregnant mice were intragastrically administered DBP dissolved in corn oil from gestational days (GD) 12.5-21.5. Maternal DBP exposure resulted in hippocampal astrocyte activation, abnormal synaptic formation, and reduced autonomic and exploratory behavior in offspring on postnatal day (PND) 22. Further studies identified that mono-n-butyl phthalate (MBP) induced astrocyte activation and proliferation by activating the AKT/NF-κB/IL-6/JAK2/STAT3 signaling pathway. Moreover, upregulated thrombospondin 1 (TSP1) in activated astrocytes regulated synaptic-related protein expression. This study highlights the neurotoxicity of maternal DBP exposure to offspring, which provides new insights into identifying potential molecular targets for the treatment of diseases related to neurological development disorders in children.

Medication-Associated Phthalate Exposure and Childhood Cancer Incidence

BACKGROUND

Human phthalate exposure is widespread through contact with myriad consumer products. Exposure is particularly high through medications formulated with phthalates. Phthalates disrupt normal endocrine signaling and are associated with reproductive outcomes and incidence of some cancers. We measured associations between gestational and childhood medication-associated phthalate exposures and the incidence of childhood cancers.

METHODS

We identified all live births in Denmark between 1997 and 2017, including both children and birth mothers. Using drug ingredient data merged with the Danish National Prescription Registry, we measured phthalate exposure through filled prescriptions for mothers during pregnancy (gestational exposure) and for children from birth until age 19 years (childhood exposure). Incident childhood cancers were ascertained from the Danish Cancer Registry, and associations were estimated with Cox regression models.

RESULTS

Among 1 278 685 children, there were 2027 childhood cancer cases diagnosed over 13.1 million person-years of follow-up. Childhood phthalate exposure was strongly associated with incidence of osteosarcoma (hazard ratio [HR] = 2.78, 95% confidence interval [CI] = 1.63 to 4.75). We also observed a positive association with incidence of lymphoma (HR = 2.07, 95% CI = 1.36 to 3.14), driven by associations with Hodgkin and non-Hodgkin lymphoma but not Burkitt lymphoma. Associations were apparent only for exposure to low-molecular phthalates, which have purportedly greater biological activity.

CONCLUSIONS

Childhood phthalate exposure was associated with incidence of osteosarcoma and lymphoma before age 19 years. Lingering questions include which specific phthalate(s) are responsible for these associations, by what mechanisms they occur, and to what extent childhood cancer cases could be avoided by reducing or eliminating the phthalate content of medications and other consumer products.

Environmental Pollution to Blame for Depressive Disorder?

Public concern has emerged about the effects of endocrine-disrupting compounds (EDCs) on neuropsychiatric disorders. Preclinical evidence suggests that exposure to EDCs is associated with the development of major depressive disorder (MDD) and could result in neural degeneration. The interaction of EDCs with hormonal receptors is the best-described mechanism of their biological activity. However, the dysregulation of the hypothalamic-pituitary-gonadal adrenal axis has been reported and linked to neurological disorders. At a worldwide level and in Mexico, the incidence of MDD has recently been increasing. Of note, in Mexico, there are no clinical associations on blood levels of EDCs and the incidence of the MDD. Methodology: Thus, we quantified for the first time the serum levels of parent compounds of two bisphenols and four phthalates in patients with MDD. The levels of di-ethyl-hexyl-phthalate (DEHP), butyl-benzyl-phthalate (BBP), di-n-butyl phthalate (DBP), and di-ethyl-phthalate (DEP), bisphenol A (BPA), and bisphenol S (BPS) in men and women with or without MDD were determined with a gas chromatograph-mass spectrometer. Results/conclusion: We found significant differences between concentrations of BBP between controls and patients with MDD. Interestingly, the serum levels of this compound have a dysmorphic behavior, being much higher in women (~500 ng/mL) than in men (≤10 ng/mL). We did not observe significant changes in the serum concentrations of the other phthalates or bisphenols tested, neither when comparing healthy and sick subjects nor when they were compared by gender. The results point out that BBP has a critical impact on the etiology of MDD disorder in Mexican patients, specifically in women.

Prenatal exposure to di(n-butyl) phthalate delays the spermatogenic cycle in rats: Investigation using a BrdU-injection method

Di(n-butyl) phthalate (DBP) esters are plasticizers that are used to provide transparency and flexibility in household plastic products but can easily leach out to contaminate organisms and the environment. We investigated whether prenatal DBP exposure affects spermatogenesis in rats. Pregnant Sprague-Dawley rats were injected with DBP 10, 50, and 100 mg/kg, or vehicle, administered intragastrically, on gestation days 12-21. At 9 or 17 weeks, 5-bromodeoxyuridine (BrdU) 50 mg/kg was injected intraperitoneally, and one testis was removed 3 h later. The remaining testis was excised 12.95 days + 3 h after the BrdU injection. Immunohistochemical analysis of BrdU was performed with periodic acid-Schiff and hematoxylin counterstaining for a quantitative analysis of the delay in one cycle of spermatogenesis. The DBP 100 mg group showed that the ratio of the appearance of seminiferous tubules in stages VII and VIII were significantly decreased, but those of stages IX and X were significantly increased compared to the Vehicle group. The reference value for the duration of spermatogenesis per cycle was set at 310.8 h. The DBP 100 mg group showed a significant delay in the duration of one cycle of spermatogenesis (16.95 h at puberty and 19.01 h at adulthood) compared with the Vehicle group. This study determined that F1-generation rats with prenatal DBP 100 mg exposure revealed significant accumulation of spermatogenic cells at stages IX to X in the second and third cycles, and the significant delay in the duration of spermatogenesis was more prominent at adulthood than in puberty.

Simple ultrasensitive electrochemical detection of the DBP plasticizer for the risk assessment of South Korean river waters

We present a simple electrochemical strategy for the ultrasensitive quantitative analysis of DBP plasticizer in water. The proposed aptasensor is comparable to GC-MS in sensitivity and it was applied to monitor the river waters contamination.

Perturbation of serum metabolome in relation to type 2 diabetes mellitus and urinary levels of phthalate metabolites and bisphenols

BACKGROUND

Emerging evidence has proved the associations between exposure to phthalates (PAEs) and bisphenols and type 2 diabetes mellitus (T2DM), but the underlying mechanisms for these associations are poorly understood. Metabolomics is a powerful tool to identify differential metabolites and metabolic pathways related to diseases and chemical exposure, which may reveal underlying mechanisms. However, little is known about the roles of metabolism in the associations for PAE and bisphenol exposure with T2DM.

OBJECTIVES

The purpose of the study was to investigate the roles of metabolism in the associations for exposure to PAEs and bisphenols with T2DM.

METHODS

In this study, 60 T2DM cases and 60 controls, who were matched in age, sex, and body mass index (BMI), were selected from the total study population in our previous studies. Fasting blood and spot urine samples of the volunteers were used for non-targeted metabolomics analysis and determination of phthalate metabolites (mPAEs) and bisphenols, respectively. The associations of urinary mPAEs and bisphenols with screened metabolic biomarkers in metabolomics analysis were analyzed using multiple linear regression models.

RESULTS

Based on non-targeted metabolomics, 19 serum metabolic biomarkers were screened between T2DM cases and controls, mostly related to galactose metabolism, amino acid metabolism, and pyrimidine metabolism. More than half of mPAEs were mostly positively associated with up-regulated metabolic biomarkers and negatively associated with down-regulated biomarkers. Different from PAEs, no evident results suggested the roles of metabolism in the associations between bisphenol exposure and T2DM.

CONCLUSIONS

Combined with the positive associations between most urinary mPAEs and T2DM in our previous study, our findings indicated that PAE exposure may contribute to T2DM risk through disturbing galactose metabolism, amino acid metabolism (especially arginine biosynthesis and alanine, aspartate and glutamate metabolism), and pyrimidine metabolism.

Unravelling the link between phthalate exposure and endometriosis in humans: a systematic review and meta-analysis of the literature

PURPOSE

Endometriosis is a chronic debilitating inflammatory pathology which interests females in their reproductive age. Its pathogenesis has not yet been clearly defined. Recent evidence linked chemical agents as endocrine-disrupting chemicals to endometriosis. Phthalates are a widely used class of such compounds. This study aimed to summarize the current literature evaluating the link between exposure to phthalates and occurrence of endometriosis.

METHODS

A systematic review of literature and meta-analysis has been carried out following PRISMA guidelines to assess such link. Fourteen studies have been included in the review. Risk of bias has been assessed through the Newcastle Ottawa Scale.

RESULTS

We observed association between endometriosis and increased urinary levels of MBP/MnBP, MEOHP, and MEHHP, but not for others. Blood-derived analysis showed statistically significant link between endometriosis and BBP, DEHP, DnBP, and MEHP.

CONCLUSION

Given the wide heterogeneity of included studies, results should be taken with caution. Further studies with more rigorous methodology are encouraged to unravel the true link between this class of toxic compounds and manifestation of endometriosis.

Prenatal exposure to phthalate esters and its impact on child development

Endocrine disruptive chemicals (EDCs) cause adverse health effects through interaction with endocrine systems. They are classified by chemical structure, effects on specific endocrine systems, their bioaccumulation and/or persistence in the environment, and/or clinically observable effects. In industrial nations, people are exposed to complex mixtures of many different substances all of which may have multiple and deleterious effects upon the individual. The clinical importance of epigenetic changes caused by the action of EDCs during vulnerable phases of development is currently unclear but of particular relevance. Epidemiological studies are criticized because reproducibility is not always guaranteed. Nevertheless, they remain the method of choice for the development and analysis of suitable model systems. Positive associations, despite of sometimes conflicting results, are the key in the selection of factors that can then be analyzed in model systems in an unbiased way. This article reports EDC-caused effects in the fields of growth and metabolism, neurocognitive development and sexual development and reproduction focusing mainly on phthalates and their metabolites. However, research will have to focus on the interactions of different EDCs and their consequences of prenatal and early life exposure.

Assessing Techniques for Quantifying the Impact of Bias Due to an Unmeasured Confounder: An Applied Example

Purpose

To compare the magnitude of bias due to unmeasured confounding estimated from various techniques in an applied example.

Patients and Methods

We examined the association between dibutyl phthalate (DBP) and incident estrogen receptor (ER)-positive breast cancer in a Danish nationwide cohort (N=1,122,042). Cox regression analyses were adjusted for age and active drug compounds contributing to DBP exposure. We estimated the hazard ratios (HRs) that would have been observed had one of the DBP sources been unmeasured and calculated the strength of confounding by comparing to the fully adjusted HR. We performed a quantitative bias analysis (QBA) of the “unmeasured” confounder, using external information to specify the bias parameters. Upper bounds on the bias were estimated and E-values were calculated.

Results

The adjusted HR for incident ER-positive breast cancer among women with high-level (≥10,000 cumulative milligrams) versus no DBP exposure was 2.12 (95% confidence interval 1.12 to 4.05). Removing each DBP source in isolation resulted in negligible change in the HR. The bias estimates from the QBA ranged from 1.00 to 1.01. The estimated maximum impact of unmeasured confounding ranged from 1.01 to 1.51. E-values ranged from 3.46 to 3.68.

Conclusion

The impact of bias due to simulated unmeasured confounding was negligible, in part, because the unmeasured variable was not independent of controlled variables. When a suspected confounder cannot be measured in the study data, our exercise suggests that QBA is the most informative method for assessing the impact. E-values may best be reserved for situations where uncontrolled confounding emanates from an unknown confounder.

Binding and detoxification ability of lactobacillus acidophilus towards di-n-butyl phthalate: Change of MAPK pathway in Caco-2 cell model

Di-n-butyl phthalate (DBP), a common compound of phthalates, can pose a risk to humans as a contaminant in the food industry. At present, the molecular mechanism of gene and protein toxicity caused by DBP in human cells is unclear. This in vitro study investigated the potential of inactivated Lactobacillus acidophilus NCFM in alleviating the damage caused by DBP in Caco-2 cells. According to the results from transcriptome and proteome analyses, the Caco-2 cells treated by DBP was resulted finally endoplasmic reticulum stress and mitochondrial oxidative damage. The most important differentially expressed genes and proteins involved in Caco-2 cells treated with NCFM to relieve DBP's cytotoxicity were TNF, NF-κB, CREB, P21, GADD45, FOS and CASP3. The molecular mechanism of DBP toxicity alleviated by strain NCFM was involved the MAPK pathway, via DBP bind to strain NCFM and avoid the activation of TNF receptor by DBP, so down-regulated the NF-κB, CREB, P21, GADD45, and CASP3, relieving the apoptosis of Caco-2 cells. Overall, our data provide new insights into detoxification of phthalate by using Lactobacillus. SIGNIFICANCE: Here we sequenced and assembled the transcriptome from Caco-2 cells which were treated with 4 groups: Control, DBP, strain NCFM, and strain NCFM+DBP groups, and combined it with proteome to characterize DBP detoxification genes/proteins through multiomics analysis. The cell viability in DBP treated groups were significantly increased by NCFM strain, indicating NCFM strain has the ability to alleviate the cytotoxicity of DBP via their binding ability with toxins. Furthermore, the results of transcriptome and proteome analysis showed that the signaling pathway of strain NCFM can alleviate DBP toxicity through MAPK pathway, and the potential biomarkers were identified too. This research may provided new information for developing new detoxification strategies for DBP.

Mono-n-Butyl Phthalate Distributes to the Mouse Ovary and Liver and Alters the Expression of Phthalate-Metabolizing Enzymes in Both Tissues

Humans are exposed to phthalates daily via items such as personal care products and medications. Reproductive toxicity has been documented in mice exposed to di-n-butyl phthalate (DBP); however, quantitative evidence of its metabolite, mono-n-butyl phthalate (MBP), reaching the mouse ovary and its effects on hepatic and ovarian biotransformation enzymes in treated mice is still lacking. Liquid chromatography/tandem mass spectrometry (LC-MS/MS) was employed to quantify MBP levels in liver, serum, and ovary from mice treated with a single or repeated exposure to the parent compound, DBP. Adult CD-1 females were pipet fed once or for 10 days with vehicle (tocopherol-stripped corn oil) or DBP at 1, 10, and 1000 mg/kg/day. Tissues and serum were collected at 2, 6, 12, and 24 h after the single or final dose and subjected to LC-MS/MS. Ovaries and livers were processed for qPCR analysis of selected phthalate-associated biotransformation enzymes. Regardless of duration of exposure (single vs repeated), MBP was detected in the tissues of DBP-treated mice. In single dose mice, MBP levels peaked at ≤6 h and fell close to background levels by 24 h post-exposure. Following the last repeated dose, MBP levels peaked at ≤2 h and fell to background levels by 12 h. Hepatic and ovarian expression of Lpl, Aldh1a1, Adh1, Ugt1a6a, and Cyp1b1 were altered in DBP-treated mice in a time- and dose-specific manner. These findings confirm that MBP reaches the mouse liver and ovary after oral exposure to DBP and influences the expression of hepatic and ovarian phthalate-associated biotransformation enzymes.

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.

Associations between medication use and phthalate metabolites in urine and follicular fluid among women undergoing in vitro fertilization

BACKGROUND

Phthalates, which are used as excipients of drugs, have been related to adverse reproductive outcomes. However, the relationships between medication use and phthalate exposure among women undergoing in vitro fertilization (IVF) have not been studied.

OBJECTIVE

To investigate the associations between the medication intake and phthalate metabolites in urine and follicular fluid (FF).

METHOD

Eight phthalate metabolites were measured in urine and FF samples from 274 women undergoing IVF using liquid chromatography-tandem mass spectrometry. Information on recent medication intake was obtained via interview by trained staff. We constructed generalized linear regression models to examine the associations of medication intake with phthalate metabolite concentrations and dose-response relationships between the number of medicines used and metabolite concentrations in two matrices.

RESULTS

Four of 10 drugs were used by more than 10% of the participants, including vitamins (23.0%), traditional Chinese medicine (TCM, 22.3%), antioxidants (12.4%) and amoxicillin (10.2%). Participants who had used TCM had 26.0% (95% CI: 0.0, 58.8%), 32.6% (95% CI: 4.2, 68.8%) and 32.3% (95% CI: 2.6, 70.6%) higher urinary mono-n-butyl phthalate (MBP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) concentrations, respectively, than those who had not. Antioxidant intake was associated with a 30.6% (95% CI: -48.5, -6.6%) decrease in the urinary MBP concentration. Compared with non-users, women who reported the use of medicines had 53.2% (95% CI: 2.7, 128.5%) higher concentrations of MMP and a 37.7% (95% CI: -60.7, -1.5%) lower level of MBP in FF, respectively.

CONCLUSION

Our data suggest that the intake of some medications may increase phthalate exposure among women undergoing IVF.

Active Surveillance of the Safety of Medications Used During Pregnancy

The scientific community relies on postmarketing approaches to define the risk of using medications in pregnancy because information available at the time of drug approval is limited. Most studies carried out in pregnancy focus on a single outcome or selected outcomes. However, women must balance the benefit of treatment against all possible adverse effects. We aimed to apply and evaluate a tree-based scan statistic data-mining method (TreeScan; Martin Kulldorff, Harvard Medical School, Boston, Massachusetts) as a safety surveillance approach that allows for simultaneous evaluation of a comprehensive range of adverse pregnancy outcomes, while preserving the overall rate of false-positive alerts. We evaluated TreeScan with a cohort design and adjustment via propensity score techniques, using 2 test cases: 1) opioids and neonatal opioid withdrawal syndrome and 2) valproate and congenital malformations, implemented in pregnancy cohorts nested within the Medicaid Analytic eXtract (January 1, 2000-December 31, 2014) and the IBM MarketScan Research Database (IBM, Armonk, New York) (January 1, 2003-September 30, 2015). In both cases, we identified known safety concerns, with only 1 previously unreported alert at the preset statistical alerting threshold. This evaluation shows the promise of TreeScan-based approaches for systematic drug safety monitoring in pregnancy. A targeted screening approach followed by deeper investigation to refine understanding of potential signals will ensure that pregnant women and their physicians have access to the best available evidence to inform treatment decisions.

Review of pregnancy in Crohn's disease and ulcerative colitis

Inflammatory bowel disease (IBD) frequently affects women of childbearing age and can have implications in pregnancy. Most women with IBD have comparable fertility with women in the general population. Fertility is reduced in women with active disease or previous ileal-pouch-anal anastomosis (IPAA) surgery and is temporarily reduced in men taking sulfasalazine. Women with IBD have an increased risk of preterm delivery, low birth weight, small-for-gestational-age infants and Cesarean section (CS) delivery, however, no increased risk of congenital abnormalities. These adverse outcomes are particularly prevalent for women with active IBD compared with those with quiescent disease. Conception should occur during disease remission to optimize maternal and fetal outcomes and reduce the risk of disease exacerbations during pregnancy. Pre-conception counseling is therefore pertinent to provide patient education, medication review for risk of teratogenicity and objective disease assessment. Most medications are safe during pregnancy and breastfeeding, with the exception of methotrexate, ciclosporin, allopurinol and tofacitinib. Delivery modality should be guided by obstetric factors in most cases; however, CS is recommended for women with active perianal disease and can be considered for women with inactive perianal disease or IPAA. In conclusion, most women with IBD have uncomplicated pregnancies. Active IBD is the predominant predictor of poor outcomes and disease exacerbations; therefore, maintenance of disease remission during and before pregnancy is crucial.

Environmentally relevant mixtures of phthalates and phthalate metabolites differentially alter the cell cycle and apoptosis in mouse neonatal ovaries†

Phthalates are a group of chemicals used as additives in various consumer products, medical equipment, and personal care products. Phthalates and their metabolites are consistently detected in humans, indicating widespread and continuous exposure to multiple phthalates. Thus, environmentally relevant mixtures of phthalates and phthalate metabolites were investigated to determine the effects of phthalates on the function of the ovary during the neonatal period of development. Neonatal ovaries from CD-1 mice were cultured with dimethyl sulphoxide (DMSO; vehicle control), phthalate mixture (0.1-100 μg/mL), or phthalate metabolite mixture (0.1-100 μg/mL). The phthalate mixture was composed of 35% diethyl phthalate, 21% di(2-ethylhexyl) phthalate, 15% dibutyl phthalate, 15% diisononyl phthalate, 8% diisobutyl phthalate, and 5% benzylbutyl phthalate. The phthalate metabolite mixture was composed of 37% monoethyl phthalate, 19% mono(2-ethylhexyl) phthalate, 15% monobutyl phthalate, 10% monoisononyl phthalate, 10% monoisobutyl phthalate, and 8% monobenzyl phthalate. After 96 h of culture, ovaries were harvested for histological analysis of folliculogenesis, gene expression analysis of cell cycle and apoptosis regulators, and immune staining for cell proliferation and apoptosis. The metabolite mixture significantly decreased the number and percentage of abnormal follicles (100 μg/mL) compared to controls. The metabolite mixture also significantly increased the expression of cell cycle inhibitors (100 μg/mL) and the antiapoptotic factor Bcl2l10 (10 μg/mL) compared to controls. The phthalate mixture did not significantly alter gene expression or follicle counts, but ovaries exposed to the phthalate mixture (0.1 μg/mL) exhibited marginally significantly increased apoptosis as revealed by DNA fragmentation staining. Overall, these data show that parent phthalates and phthalate metabolites differentially impact ovarian function.

Moderating effects of plastic packaged food on association of urinary phthalate metabolites with emotional symptoms in Chinese adolescents

Previous research reports that diet is the main source of phthalate exposure to adolescents, and phthalate is associated with adolescent mental and behavioral problems. However, no study has explored the moderating effects of eating behavior in this association. This study aimed to analyze the moderating effects of plastic packaged food consumption in the longitudinal association between phthalate metabolite concentration and emotional symptoms in adolescents. This school-based survey was carried out among adolescents in two Chinese provinces. We conducted a baseline and follow-up surveys for 893 freshmen using the purposive sampling method from December 2018 to November 2019. We used food frequency questionnaire to assess eating behavior. The Chinese version of 21-item Depression Anxiety Stress Scales was used to assess emotional symptoms, and high-performance liquid chromatography-tandem mass spectrometry was used to analyze the concentration of six urine phthalate metabolites. The results of latent moderation model indicated that plastic packaged food consumption moderated the association of low molecular weight phthalate (LMWP) with depressive symptoms (β = 0.27, P = 0.002), anxiety symptoms (β = 0.89, P < 0.01), and stress symptoms (β = 0.23, P = 0.019). The moderating effects were significant at the higher scores (β = 0.14-0.35, P < 0.05) and/or the lower scores (β = -0.35 to -0.12, P < 0.05) of plastic packaged food consumption. The results suggest that plastic packaged food consumption to some extent moderates the longitudinal association of phthalate exposure with emotional symptoms in adolescents.

Levels and determinants of urinary phthalate metabolites in Chinese community-dwelling older adults

BACKGROUND

Biomonitoring studies have demonstrated extensive exposure of infants, children, and pregnant women to phthalates, but data on phthalate exposure and their determinants in Chinese older adults remain insufficient. This study aims to assess urinary phthalate metabolite levels, individual and cumulative exposure risk, and their determinants in Chinese community-dwelling older adults.

METHODS

A total of 987 individuals aged 60 years or over were included in this study. The urinary levels of seven phthalate metabolites were measured using high-performance liquid chromatography-tandem mass spectrometry. The estimated daily intake (EDI), hazard quotient (HQ), and hazard index (HI) of phthalates were calculated based on urinary metabolite levels. The associations between phthalate metabolite levels and potential determinants were examined using multiple linear regressions.

RESULTS

Detection rates of seven phthalate metabolites from the study population ranged from 63.83% to 99.39%. The highest median concentration was 43.64 μg/L (42.59 μg/g creatinine) for mono-butyl phthalate (MBP). The highest median EDI was 1.55 μg/kg-bw/day for diethyl phthalate (DBP). Nearly 5% of participants had high HI values exceeding 1, mainly attributed to DBP and di-2-ethylhexyl phthalate (DEHP). Furthermore, we found that females, higher body mass index (BMI), smoking, having two or more chronic diseases, and vegetable-based diets were significantly associated with higher levels of parts of phthalate metabolites. More interestingly, higher urine levels of high-molecular-weight (HMW) phthalate metabolites and lower urine levels of low-molecular-weight (LMW) phthalate metabolites were found in rural older adults than in urban older adults.

CONCLUSIONS

Chinese community-dwelling older adults are extensively exposed to phthalates, especially to DBP and DEHP. More attention should be paid to urban-rural differences in exposure to HMW and LMW phthalates and to phthalate exposure among older adults with overweight/obesity, females, and individuals who are current heavy smokers, have two or more chronic diseases, and consume vegetable-based diets.

The Association of Bisphenol A and Phthalates with Risk of Breast Cancer: A Meta-Analysis

Background: Breast cancer is the most common cancer and the second leading cause of cancer-related death amongst American women. Endocrine-disrupting chemicals (EDCs), especially bisphenol A (BPA) and phthalates, have adverse effects on human health. However, the association of BPA and phthalates with breast cancer remains conflicting. This study aims to investigate the association of BPA and phthalates with breast cancer. Methods: Correlative studies were identified by systematically searching three electronic databases, namely, PubMed, Web of Sciences, and Embase, up to November 2020. All data were analyzed using Stata 15.0. Results: A total of nine studies, consisting of 7820 breast cancer cases and controls, were included. The urinary phthalate metabolite mono-benzyl phthalate (MBzP) and mono-2-isobutyl phthalate (MiBP) were negatively associated with breast cancer (OR = 0.73, 95% CI: 0.60–0.90; OR = 0.75, 95% CI: 0.58–0.98, respectively). However, the overall ORs for BPA, mono-ethyl phthalate (MEP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-2-ethylhexyl phthalate (MEHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono-(3-carboxypropyl) phthalate (MCPP), and mono-butyl phthalate (MBP) were 0.85 (95% CI: 0.69–1.05), 0.96 (95% CI: 0.62–1.48), 1.12 (95% CI: 0.88–1.42), 1.13 (95% CI: 0.74–1.73), 1.01 (95% CI: 0.74–1.40), 0.74 (95% CI: 0.48–1.14), and 0.80 (95% CI: 0.55–1.15), respectively, suggesting no significant association. The sensitivity analysis indicated that the results were relatively stable. Conclusion: Phthalate metabolites MBzP and MiBP were passively associated with breast cancer, whereas no associations were found between BPA, MEP, MEHHP, MEHP, MEOHP, MCPP, and MBP and breast cancer. More high-quality case-control studies or persuasive cohort studies are urgently needed to draw the best conclusions.

Use of medications during pregnancy and breastfeeding for Crohn's disease and ulcerative colitis

Introduction: The peak age of diagnosis of inflammatory bowel disease (IBD) occurs during childbearing years, therefore management of IBD during pregnancy is a frequent occurrence. Maintenance of disease remission is crucial to optimize pregnancy outcomes, and potential maternal or fetal toxicity from medications must be balanced against the risks of untreated IBD.Areas covered: This review summarizes the literature on safety and use of medications for IBD during pregnancy and lactation.Expert opinion: 5-aminosalicylates, corticosteroids and thiopurines are safe for use during pregnancy, while methotrexate and tofacitinib should only be used with extreme caution. Anti-TNF agents (except certolizumab), vedolizumab, ustekinumab and tofacitinib readily traverse the placenta via active transport, therefore theoretically may affect fetal development. Certolizumab only undergoes passive transfer across the placenta, thus has markedly lower cord blood levels making it likely the safest biologic agent for infants. There is reasonable evidence to support the safety of anti-TNF monotherapy and combination therapy during pregnancy and lactation. Vedolizumab and ustekinumab are also thought to be safe in pregnancy and lactation, while tofacitinib is generally avoided due to teratogenic effects in animal studies.

Genotoxic risk assessment and mechanism of DNA damage induced by phthalates and their metabolites in human peripheral blood mononuclear cells

The human genome is persistently exposed to damage caused by xenobiotics, therefore the assessment of genotoxicity of substances having a direct contact with humans is of importance. Phthalates are commonly used in industrial applications. Widespread exposure to phthalates has been evidenced by their presence in human body fluids. We have assessed the genotoxic potential of selected phthalates and mechanism of their action in human peripheral blood mononuclear cells (PBMCs). Studied cells were incubated with di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP) and their metabolites: mono-n-butylphthalate (MBP), mono-benzylphthalate (MBzP) in the concentrations range of 0.1-10 µg/mL for 24 h. Analyzed compounds induced DNA single and double strand-breaks (DBP and BBP ≥ 0.5 µg/mL, MBP and MBzP ≥ 1 µg/mL) and more strongly oxidized purines than pyrimidines. None of the compounds examined was capable of creating adducts with DNA. All studied phthalates caused an increase of total ROS level, while hydroxyl radical was generated mostly by DBP and BBP. PBMCs exposed to DBP and BBP could not completely repair DNA strand-breaks during 120 min of postincubation, in opposite to damage caused by their metabolites, MBP and MBzP. We have concluded that parent phthalates: DBP and BBP caused more pronounced DNA damage compared to their metabolites.

Assessing the Public Health Implications of the Food Preservative Propylparaben: Has This Chemical Been Safely Used for Decades

PURPOSE

Parabens are chemicals containing alkyl-esters of p-hydroxybenzoic acid, which give them antimicrobial, antifungal, and preservative properties. Propylparaben (PP) is one paraben that has been widely used in personal care products, cosmetics, pharmaceuticals, and food. In this review, we address the ongoing controversy over the safety of parabens, and PP specifically. These chemicals have received significant public attention after studies published almost 20 years ago suggested plausible associations between PP exposures and breast cancer.

RECENT FINDINGS

Here, we use key characteristics, a systematic approach to evaluate the endocrine disrupting properties of PP based on features of "known" endocrine disruptors, and consider whether its classification as a "weak" estrogen should alleviate public health concerns over human exposures. We also review the available evidence from rodent and human studies to illustrate how the large data gaps that exist in hazard assessments raise concerns about current evaluations by regulatory agencies that PP use is safe. Finally, we address the circular logic that is used to suggest that because PP has been used for several decades, it must be safe. We conclude that inadequate evidence has been provided for the safe use of PP in food, cosmetics, and consumer products.

Independent and combined effects of Bisphenol A and Diethylhexyl Phthalate on gestational outcomes and offspring development in Sprague-Dawley rats

Bisphenol A (BPA) and Diethylhexyl Phthalate (DEHP) are well-studied endocrine disrupting chemicals (EDCs), however, the effects of mixtures of these EDCs are not. To assess the consequences of prenatal exposure to a mixture of these EDCs, dams were orally administered either saline (control), BPA (5 μg/kg BW/day), high dose DEHP (HD-D; 7.5 mg/kg BW/day), or a combination of BPA with HD-D in experiment 1; saline, BPA (5 μg/kg BW/day), low-dose DEHP (LD-D; 5 μg/kg BW/day) or a combination of BPA with LD-D in experiment 2. Gestational weights, number of abortions, litter size and weights, number of live births and stillbirths were recorded. Morphometric measures were obtained at birth and body weight, food and water intake were monitored weekly from postnatal weeks 3-12. Offspring were sacrificed at 16-24 weeks of age and organ weights were measured. The abortion rate of dams exposed to HD-D and the mixtures, BPA + LD-D and BPA + HD-D were higher at 9, 14 and 27% respectively. Prenatal exposure to BPA or HD-D significantly decreased relative thymus weights in male but not female offspring. Apoptotic cells were detected in thymus sections of both male and female offspring prenatally exposed to DEHP. Relative heart weights increased in BPA + HD-D exposed male offspring compared to the other groups. The results indicate that a mixture of BPA and DEHP, produced a pronounced effect on pregnancy outcomes. Male offspring appear to be more susceptible to the programming effects of these EDCs or their mixture suggesting a need to reconsider the possible additive, antagonistic or synergistic effects of EDC mixtures.

Adsorption kinetics and mechanism of di-n-butyl phthalate by Leuconostoc mesenteroides

Di-n-butyl phthalate (DBP) poses a risk to humans as a ubiquitous environmental contaminant. A strain of Leuconostoc mesenteroides DM12 was chosen from lactic acid bacteria strains to study the DBP binding mechanisms. Adsorption of DBP by strain DM12 reached the highest binding rate of 87% after 11 hr of incubation, which could be explained by pseudo-second-order kinetics. The adsorption isotherm coincided with the model of Langmuir-Freundlich, indicating physical and chemical adsorption processes involved. Further, NaIO4 and TCA treatments were used to analyze the DBP binding mechanism of strain DM12, which indicated that peptidoglycan on the bacterial cell wall was involved in the process. The O-H, C-O, and N-H bonds were possibly involved in the binding process as the main functional groups.

Unwitting Accomplices: Endocrine Disruptors Confounding Clinical Care

Burgeoning evidence over the last 25 years has identified myriad synthetic chemicals with the capacity to alter various aspects of hormone synthesis and action. These endocrine-disrupting chemicals (EDCs) have been linked to various diseases, including reproductive disorders, metabolic diseases, and developmental abnormalities, among others. Exposure to EDCs arises from industrial activity, use of personal and home care products, and consumption of contaminated food and water; however, the role of healthcare in exposing individuals to EDCs is grossly underappreciated. Indeed, through the use of medications as well as medical equipment and devices, healthcare providers are unknowing mediators of exposure to EDCs, chemicals that might not only promote disease but that may also antagonize the efficacy of treatments. The ethical implications of provider-dependent exposure are profound. A failure to disclose the endocrine-disrupting properties of medical interventions violates core principles of nonmaleficence, patient autonomy, and justice as well as the practice of informed consent. Furthermore, physicians' lack of knowledge regarding EDCs in medical practice artificially skews risk-benefit calculations that are fundamental to informed medical decision-making. To combat this underappreciated ethical challenge, urgent action is required. Healthcare providers must be educated about endocrine disruption. Known EDCs, defined by endocrinologists, should be clearly labeled on all medical products, and all medication components and devices should be screened for endocrine-disrupting properties. Finally, communication strategies must be devised to empower patients with knowledge about these risks. Providing ethically competent care requires an open acknowledgment of endocrine risks imposed by the medical community that have heretofore been ignored.

The levels of phthalate exposure and associations with obesity in an elderly population in China

BACKGROUND

Few epidemiological studies on the correlation between phthalate exposure and elderly obesity in China are available. The purpose of the present study is to assess phthalate exposure levels and explore the connections between exposure to phthalates and obesity using a sample of Chinese community-dwelling elderly individuals.

METHODS

Data were acquired from the baseline survey of the Cohort of Health of Elderly and Controllable Factors of Environment, which was established in Lu'an, Anhui province, China, from June to September in 2016. Urine samples were obtained to analyze the concentrations of seven phthalate metabolites, utilizing a high-performance liquid chromatography-tandem mass spectrometry method. General obesity was determined based on body mass index, and abdominal obesity based on waist circumference. Binary logistic regression models were utilized to analyze the associations of creatinine-corrected phthalate metabolite concentrations (categorized into quartiles) with general and abdominal obesity in elderly people. Moreover, a stratified analysis was performed to explore the difference between genders.

RESULTS

Of 942 elderly individuals, 52.9% were defined as generally obese and 75.5% as abdominally obese. The detection rates of seven phthalate metabolites ranged from 90.07% to 99.80%. The highest median concentration was 44.08 μg/l (for MBP), and the lowest was 0.55 μg/l (for MEHP). The level of exposure to LMW(low-molecular-weight) PAEs is higher than that to HMW(high-molecular-weight) PAEs. After adjustment for confounding variables, we found a significant association between urinary MEOHP (mono-2-ethyl-5-oxohexyl phthalate), MEHP (mono-2-ethylhexyl phthalate), MBP (mono-n-butyl phthalate), MEP (mono-ethyl phthalate), and MMP (mono-methyl phthalate) levels and general obesity. MBP levels were also correlated with abdominal obesity. When stratified by gender, higher urinary levels of MEOHP, MBP, MEP, and MMP were associated with general obesity in males, whereas MBP and MMP levels were eminently correlated with general obesity in females. Higher urinary MBP levels were associated with increased abdominal obesity rates in males, but not in females.

CONCLUSIONS

In conclusion, higher phthalate metabolite concentrations were correlated with obesity in the elderly. Moreover, a gender difference was observed in these associations.

Dibutyl phthalate promotes juvenile Sertoli cell proliferation by decreasing the levels of the E3 ubiquitin ligase Pellino 2

BACKGROUND

A previous study showed that dibutyl phthalate (DBP) exposure disrupted the growth of testicular Sertoli cells (SCs). In the present study, we aimed to investigate the potential mechanism by which DBP promotes juvenile SC proliferation in vivo and in vitro.

METHODS

Timed pregnant BALB/c mice were exposed to vehicle, or DBP (50, 250, and 500 mg/kg/day) from 12.5 days of gestation until delivery. In vitro, CCK-8 and EdU incorporation assays were performed to determine the effect of monobutyl phthalate (MBP), the active metabolite of DBP, on the proliferation of TM4 cells, which are a juvenile testicular SC cell line. Western blotting analysis, quantitative PCR (q-PCR), and flow cytometry were performed to analyse the expression of genes and proteins related to the proliferation and apoptosis of TM4 cells. Coimmunoprecipitation was used to determine the relationship between the ubiquitination of interleukin 1 receptor-associated kinase 1 (IRAK1) and the effect of MBP on promoting the proliferation of TM4 cells.

RESULTS

In the 50 mg/kg/day DBP-exposed male mice offspring, the number of SCs was significantly increased. Consistent with the in vivo results, in vitro experiments revealed that 0.1 mM MBP treatment promoted the proliferation of TM4 cells. Furthermore, the data showed that 0.1 mM MBP-mediated downregulation of the E3 ubiquitin ligase Pellino 2 (Peli2) increased ubiquitination of IRAK1 by K63, which activated MAPK/JNK signalling, leading to the proliferation of TM4 cells.

CONCLUSIONS

Prenatal exposure to DBP led to abnormal proliferation of SCs in prepubertal mice by affecting ubiquitination of the key proliferation-related protein IRAK1 via downregulation of Peli2.

Developmental, behavioral and endocrine alterations in male rats at early and late postnatal life following in utero exposure to low dose di-n-butylphthalate

Environmental chemical pollutants that interfere with hormonal homeostasis or hormone signaling are the relevant agents inducing congenital or postnatally developed reproductive abnormalities in human beings, wild and domestic animals. In this study, we are examining reproductive effects of prenatal exposure of male rats to a low dose di-n-butylphthalate (DBP). Wistar female rats were given intragastrically DBP at a daily dose of 100 mg/kg b.w. during 15th-21st days of pregnancy. Anogenital distance (AGD) in male offspring decreased on postnatal day (PND) 2 followed by its normalization on PND 7 and 10. There were no other visible teratogenic lesions in the newborns. The testicle descent into scrotum of control males occurred on PND 38.5 ± 0.1, while in DBP group it accelerated by 5.3 days on the average. At the age of 6 months, DBP-exposed animals exhibited double increase of blood plasma testosterone level as compared to controls, and hyperactive male sexual behavior in the presence of receptive female. The duration of latent periods of the first mount and the first intromission, as well as post-ejaculatory refractory period, have been shortened; the number of mounts with intromission and the number of ejaculations increased significantly. Histological examination of the testes indicated activation of Leydig cells. The female-type sexual behavior as evaluated by appearance of lordosis of orchidectomized and primed with estradiol and progesterone 10-month-old males in response to mount or approach of sexually active normal male was enhanced in DBP-group. Both 10-month-old and aging males (18 months), castrated and hormone-primed, displayed homosexual type of behavior. Prenatal low dose DBP caused in 18-month-old males premature atrophy of the testes and accessory sexual glands, increased number of Leydig cell adenomas, a twice decrease of plasma testosterone level and exhausting of sexual potency. We concluded that prenatal exposition of male rats to low dose DBP determines epigenetic alterations of programming of sex brain differentiation and regulation of testicular steroidogenesis that leads to reproductive disorders and accelerated aging of reproductive system.

Reconstruction of phthalate exposure and DINCH metabolites from biomonitoring data from the EXHES cohort of Tarragona, Spain: A case study on estimated vs reconstructed DEHP using the PBPK model

Phthalates are known endocrine disruptors (EDs) and are associated with potential diseases, such as obesity and diabetes. In 2002, the plasticizer 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH) was introduced as an alternative to phthalates in the European market. The objective of this study was to evaluate the total exposure to phthalate and DINCH metabolites from EXHES Tarragona, Spain cohort of pregnant women. On the one hand, the analytical determination of phthalate and DINCH metabolites in urine was carried out. On the other hand, the reconstructed exposure was calculated for phthalates and DINCH using their metabolites concentration measured in the urine. Thirteen different phthalate metabolites and two metabolites of DINCH were measured and detected in almost all pregnant women's urine samples (n = 60). There were significant correlations between metabolites of the same parent compounds, and also between DEHP and MBzP metabolites, DiNP and BBZP metabolites, and DEHP and DiNP metabolites respectively. The exposure of pregnant women to phthalate and DINCH parent compounds were also back calculated using the levels of each metabolite found in pregnant women urine (reconstructed exposure). Besides, to demonstrate the utility of this approach, the physiologically based pharmacokinetic (PBPK) model was used to predict the cumulative amount of MEHP (a principal metabolite of DEHP in urine). To proceed with that, DEHP reconstructed exposure and estimated exposure from the same cohort (previously studied by the same authors) were simulated using the PBPK model. Results showed that the reconstructed-PBPK simulation was closer to the 24 h biomonitoring data than the estimated PBPK-simulation., This clearly shows that the combination of reconstructed exposure with the PBPK model is a good tool to predict chemicals exposure. However, some discrepancies between simulated and biomonitored values were found. This can be associated with other sources that contribute to the total exposure and emphasises the need to consider multi-routes exposure for the widely distributed chemicals like phthalates and DINCH.

Association of urinary phthalates metabolites concentration with emotional symptoms in Chinese university students

Previous studies have shown the associations between phthalates exposure and psychological behavior problems in children and adolescents, but such associations have not been fully elucidated in university students, especially among Chinese university students. This study aims to examine the association between urinary phthalates metabolites concentration and emotional symptoms in Chinese university students. A school-based cross-sectional survey was carried out among 990 university students aged 17-24 years from two universities in Anhui and Jiangxi provinces of China. Concentration of six phthalate metabolites in urine was determined by high-performance liquid chromatography-tandem mass spectrometry and the emotional symptoms were assessed by the 21-item Depression, Anxiety, and Stress Scale. The detection rate of six phthalate metabolites in urine ranged from 79.6% to 99.7%. The median concentration of six phthalate metabolites ranged from 2.90 to 119.64 ng/mL. The positive rates of depressive symptoms, anxiety symptoms, and stress were 17.4%, 24.8%, and 9.5%, respectively. After adjusting for the confounding variables, mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) was found to be associated with depressive symptoms (β = 8.84, P = 0.017), anxiety symptoms (β = 8.46, P = 0.015), and stress symptoms (β = 9.95, P = 0.012) in males; whereas, monobutyl phthalate (MBP) was found to be associated with depressive symptoms (β = 1.86, P = 0.002), anxiety symptoms (β = 1.81, P = 0.005), and stress symptoms (β = 1.48, P = 0.047) in females. Our study demonstrates that Chinese university students are widely exposed to phthalates; and high- and low-molecular weight phthalates are associated with emotional symptoms in males and females, respectively.

Effect of environmental and pharmaceutical exposures on fetal testis development and function: a systematic review of human experimental data

BACKGROUND

Overall, the incidence of male reproductive disorders has increased in recent decades. Testicular development during fetal life is crucial for subsequent male reproductive function. Non-genomic factors such as environmental chemicals, pharmaceuticals and lifestyle have been proposed to impact on human fetal testicular development resulting in subsequent effects on male reproductive health. Whilst experimental studies using animal models have provided support for this hypothesis, more recently a number of experimental studies using human tissues and cells have begun to translate these findings to determine direct human relevance.

OBJECTIVE AND RATIONALE

The objective of this systematic review was to provide a comprehensive description of the evidence for effects of prenatal exposure(s) on human fetal testis development and function. We present the effects of environmental, pharmaceutical and lifestyle factors in experimental systems involving exposure of human fetal testis tissues and cells. Comparison is made with existing epidemiological data primarily derived from a recent meta-analysis.

SEARCH METHODS

For identification of experimental studies, PubMed and EMBASE were searched for articles published in English between 01/01/1966 and 13/07/2018 using search terms including ‘endocrine disruptor’, ‘human’, ‘fetal’, ‘testis’, ‘germ cells’, ‘testosterone’ and related search terms. Abstracts were screened for selection of full-text articles for further interrogation. Epidemiological studies involving exposure to the same agents were extracted from a recent systematic review and meta-analysis. Additional studies were identified through screening of bibliographies of full-texts of articles identified through the initial searches.

OUTCOMES

A total of 25 experimental studies and 44 epidemiological studies were included. Consistent effects of analgesic and phthalate exposure on human fetal germ cell development are demonstrated in experimental models, correlating with evidence from epidemiological studies and animal models. Furthermore, analgesic-induced reduction in fetal testosterone production, which predisposes to the development of male reproductive disorders, has been reported in studies involving human tissues, which also supports data from animal and epidemiological studies. However, whilst reduced testosterone production has been demonstrated in animal studies following exposure(s) to a variety of environmental chemicals including phthalates and bisphenol A, these effects are not reproduced in experimental approaches using human fetal testis tissues.

WIDER IMPLICATIONS

Direct experimental evidence for effects of prenatal exposure(s) on human fetal testis development and function exists. However, for many exposures the data is limited. The increasing use of human-relevant models systems in which to determine the effects of environmental exposure(s) (including mixed exposures) on development and function of human tissues should form an important part of the process for assessment of such exposures by regulatory bodies to take account of animal–human differences in susceptibility.

Investigation of phthalate metabolites in urine and daily phthalate intakes among three age groups in Beijing, China

Phthalates are widely used as binders and plasticizers in industrial and consumer products but show diverse toxicity. We investigated the level of human exposure to phthalates in Beijing, one of the most densely populated cities in the world. In this study, 12 metabolites of phthalates were measured in 70 spot urine samples collected from Beijing residents from August 2017 to April 2018 using ultra high-performance liquid chromatography tandem mass spectrometry. We found that metabolites of phthalates were ubiquitous in all urine samples. Total concentrations of phthalate metabolites ranged from 39.6 to 1931 ng mL^-1, with median concentrations were in decreasing order of children (371 ng mL^-1)> younger adults (332 ng mL^-1)> older adults (276 ng mL^-1). Mono-n-butyl phthalate (MnBP) was the predominant compound, and occurred at concentrations greater than those reported for people in other countries. The mean values of estimated daily intakes (EDIs) of ∑phthalate were 35.2, 10.3 and 10.9 ng (kg-bm)^-1 d^-1 for children, younger adults and older adults, respectively. EDIs of di-n-butyl phthalate (DnBP), di-iso-butyl phthalate (DiBP) and di-(2-ethylhexyl) phthalate (DEHP) exceeded reference values suggested by the US Environmental Protection Agency and the European Food Safety Authority. When concentrations were normalized to volume or creatinine-adjusted, hazard quotients (HQs) for 40 of 70 participants exhibited larger HQs >1 for individual phthalates, which was indicative of potential for adverse effects. Thus, exposure to phthalates might be a critical factor contributing to adverse health effects in Beijing residents. To the best of our knowledge, this is the first study to establish a pre-baseline level of urinary phthalate metabolites among residents in Beijing.

Risk assessment for humans using physiologically based pharmacokinetic model of diethyl phthalate and its major metabolite, monoethyl phthalate

Diethyl phthalate (DEP) belongs to phthalates with short alkyl chains. It is a substance frequently used to make various products. Thus, humans are widely exposed to DEP from the surrounding environment such as food, soil, air, and water. As previously reported in many studies, DEP is an endocrine disruptor with reproductive toxicity. Monoethyl phthalate (MEP), a major metabolite of DEP in vivo, is a biomarker for DEP exposure assessment. It is also an endocrine disruptor with reproductive toxicity, similar to DEP. However, toxicokinetic studies on both MEP and DEP have not been reported in detail yet. Therefore, the objective of this study was to evaluate and develop physiologically based pharmacokinetic (PBPK) model for both DEP and MEP in rats and extend this to human risk assessment based on human exposure. This study was conducted in vivo after intravenous or oral administration of DEP into female (2 mg/kg dose) and male (0.1-10 mg/kg dose) rats. Biological samples consisted of urine, plasma, and 11 different tissues. These samples were analyzed using UPLC-ESI-MS/MS method. For DEP, the tissue to plasma partition coefficient was the highest in the kidney, followed by that in the liver. For MEP, the tissue to plasma partition coefficient was the highest in the liver. It was less than unity in all other tissues. Plasma, urine, and fecal samples were also obtained after IV administration of MEP (10 mg/kg dose) to male rats. All results were reflected in a model developed in this study, including in vivo conversion from DEP to MEP. Predicted concentrations of DEP and MEP in rat urine, plasma, and tissue samples using the developed PBPK model fitted well with observed values. We then extrapolated the PBPK model in rats to a human PBPK model of DEP and MEP based on human physiological parameters. Reference dose of 0.63 mg/kg/day (or 0.18 mg/kg/day) for DEP and external doses of 0.246 μg/kg/day (pregnant), 0.193 μg/kg/day (fetus), 1.005-1.253 μg/kg/day (adults), 0.356-0.376 μg/kg/day (adolescents), and 0.595-0.603 μg/kg/day (children) for DEP for human risk assessment were estimated using Korean biomonitoring values. Our study provides valuable insight into human health risk assessment regarding DEP exposure.