Phthalates (PAEs) and reproductive toxicity: Hypothalamic-pituitary-gonadal (HPG) axis aspects

Influence of exposure to endocrine disruptors and other environmental chemicals on breast development in girls: A systematic review of human studies

BACKGROUND

Age at thelarche has decreased over recent decades. This change in female puberty timing may be influenced by exposure to endocrine disrupting chemicals (EDCs) during critical periods of development.

OBJECTIVE

To review the scientific literature for evidence on the association of exposure to EDCs and other environmental chemicals with the timing of thelarche in girls.

METHODS

A systematic search for original peer-reviewed articles published up to July 2023 was conducted in three databases (Medline/PubMed, Scopus, and Web of Science), following the PECO strategy and PRISMA guidelines. The quality of evidence and reporting and the risk of bias were evaluated using GRADE, STROBE, and ROBINS-E tools.

RESULTS

Out of 3094 articles retrieved in the search, 67 met the review inclusion criteria. Data from 10 out of the 14 studies offering high-quality suggest that in utero and/or childhood exposure to certain synthetic and natural chemicals is associated with earlier breast development in girls; 8 of these 10 studies described a relationship with exposure to organohalogenated compounds in utero and to phthalates in childhood.

CONCLUSIONS

This systematic review provides the first overview of available human data on the association of EDCs/environmental chemicals with the timing of thelarche. Further high-quality research is urgently needed to fully elucidate the influence of this exposure on breast development timing in girls.

Insights into organophosphorus insecticide malathion induced reproductive toxicity and intergenerational effect in zebrafish (Danio rerio)

The reproductive and transgenerational effects of malathion, a widely utilized low-toxicity organophosphorus insecticide, were explored using zebrafish as model animal. Adult zebrafish (F0) were exposed to malathion at 0.1-1.0 mg/L for 60 days for exploring the reproductive toxicity in sex differences and the potential mechanisms, and development and transcription levels in F1 offspring were assessed. Malathion significantly suppressed the fertility of zebrafish as evidenced by reduced spawning and lower fertilization rates in F1 offspring. Abnormal gonadal development and steroid hormone disorders were observed in F0 zebrafish, which was associated with the alterations in the transcription of core genes (such as cyp11a, cyp19a, vtg1, era) along the hypothalamus-pituitary-gonad-liver (HPGL) axis. The expression level of vtg1 played a key role in the malathion-induced sex dependence on E2 and VTG levels. The reduction of E2 and VTG could disrupt ovarian capability in females. E2 excess would cause feminization in males. Molecular docking indicated that reproductive disorders induced by malathion in zebrafish mainly through estrogen-like effects and CYP11A antagonism. Parental exposure to malathion abnormalized embryonic development in F1 offspring, comprising heartbeats decrease, deformities and body length reduction. Transcriptomics suggested that malathion-induced reproductive toxicity could be transmitted across generations, which may adversely affect fish populations.

Multi-omics analysis of the toxic effects on gill tissues of crucian carp (Carassius auratus) from chronic exposure to environmentally relevant concentrations of Di(2-ethylhexyl) phthalate (DEHP)

The pervasive use of the plasticizer di(2-ethylhexyl) phthalate (DEHP) poses potential risks to global aquatic ecosystems. This study systematically evaluated the adverse effects of chronic exposure to environmentally relevant concentrations of DEHP on gill tissues of crucian carp, utilizing histological examination, metabolomic, and transcriptomic analysis. The results demonstrated that DEHP induced significant histopathological alterations in gill tissues, with significant enrichment observed in multiple pathways associated with amino acid, hormone, lipid, and xenobiotic metabolism. Metabonomics-transcriptomics analyses indicated that DEHP-induced significantly over-activation of cytochrome P450 1B1-like (p < 0.001) and cytochrome P450 3A30-like (p < 0.05) via the nuclear xenobiotic receptors pathway was a key factor contributing to the disruption of tryptophan metabolism and steroid hormone biosynthesis, as well as inducing circadian rhythm disruption. Moreover, circadian rhythm disruption further exacerbated the imbalance of cytochrome P450 (CYP450) enzyme system as well as linoleic acid, arachidonic acid, sphingolipid, and glycerophospholipid metabolism. Overall, the feedback regulation between the CYP450 enzyme system and circadian rhythms emerged as the primary mechanism underlying DEHP-induced metabolic and transcriptional disruptions, ultimately resulting in gill toxicity. This study not only enriched the toxic effects on aquatic organisms of chronic exposure to DEHP, but provided potential biomarkers for the environmental risk assessment of DEHP.

Adolescent exposure to organophosphate insecticide malathion induces spermatogenesis dysfunction in mice by activating the HIF-1/MAPK/PI3K pathway

Chemical-caused reproductive dysfunction has emerged as a global public health concern. This study investigated the adverse effects of the organophosphorus pesticide malathion on reproductive function in adolescent male mice at environmentally relevant concentrations. The results indicated that eight-week malathion exposure reduced testis weight, caused sex and thyroid hormone disorders, and induced testicular spermatogenic epithelium damage and oxidative stress. Testicular RNA sequencing indicated that malathion significantly affected testicular energy metabolism, hypoxia-inducible factor 1 (HIF-1) signaling, and steroid hormone biosynthesis pathways. Malathion significantly increased the gene and protein expression of HIF-1α by upregulating key genes in the mitogen-activated protein kinase (MAPK) pathway (Map2k2, Mapk3, and Eif4e2) and the phosphatidylinositol 3-kinase (PI3K) pathway (Pik3r2 and Akt1). Furthermore, malathion downregulated HIF-1α degradation-regulating genes while upregulating anaerobic metabolism and inflammation-related genes, thereby inhibiting normoxia and promoting hypoxia processes. Testicular hypoxia subsequently induced steroid hormone biosynthesis disorders and spermatogenesis dysfunction. Molecular docking verified that malathion interfered with HIF-1α and steroid hormone synthases (CYP11A1, CYP17A1 and CYP19A1) by forming hydrogen bonds and hydrophobic interactions with these proteins. This study presents the first evidence that malathion triggers spermatogenesis dysfunction in mice through activating the HIF-1/MAPK/PI3K pathway, providing a comprehensive understanding of the reproductive toxicity risks associated with organophosphorus pesticides.

Simultaneous analysis of PAEs in edible oil and dietary exposure assessment in Hubei

Phthalic acid esters (PAEs), widely used in food processing, pose significant risks to food safety and human health. A rapid and accurate method to simultaneously detect 18 PAEs in edible oil was developed and applied to evaluate daily exposures in Hubei. By using ultrasound-assisted extraction and GC-MS with deuterated isotopes, we improved extraction efficiency and detection accuracy. The method exhibited excellent linearity and low limits of quantification, with average recoveries ranging from 84.32 % to 115.80 % and relative standard deviations between 2.08 % and 12.82 %. Among 30 commercial edible oils analyzed, higher average levels of DBP, DEHP, and DINP were found at 0.207, 1.767, and 0.600 mg/kg, respectively. Dietary exposure assessment indicated that daily intakes were below health guideline values, but DEHP posed a relatively higher health risk. These findings provide a simple method and reference for assessing PAEs exposure and health risk in edible oil.

Characteristics, sources, and concentration prediction of endocrine disruptors in a large reservoir driven by hydrological rhythms: A case study of the Danjiangkou Reservoir

Herein, we present the first systematic investigation to clarify the effect of hydrological rhythms on the concentrations and distributions of polycyclic aromatic hydrocarbons (PAHs) and phthalate esters (PAEs) in the Danjiangkou Reservoir. The results revealed that hydrological rhythms remarkably affected the PAH and PAE concentrations and distributions in the water body, wherein the PAH concentration peaked in the flood season while the PAE concentration remarkably increased in the dry season. This study represents methodological innovation, revealing significant heterogeneity of PAHs and PAEs across different water layers. The former compounds tended to accumulate in the water body's bottom layer while the latter compounds had the highest concentration at the surface layer, which can be attributed to the different physicochemical properties and environmental transport behaviors of the two compound types. The overall concentrations of PAHs and PAEs fall within the international and domestic safety standards. The primary sources of these contaminants-coal and biomass combustion for PAHs and widespread use of plastic products for PAEs-are critical areas of regulatory focus. A machine learning model is proposed for the first time for predicting PAE concentrations in the Danjiangkou Reservoir, primarily based on the stacking model and supplemented by the random forest or XGBoost models.

Combined effects and potential mechanisms of phthalate metabolites on serum sex hormones among reproductive-aged women: An integrated epidemiology and computational toxicology study

The reproductive age is a crucial stage for women to bear offspring. However, reproductive-aged women are simultaneously exposed to various phthalates, which may pose a threat to their reproductive health. This study employed generalized linear regression and weighted quantile sum (WQS) regression to explore the associations between monoesters of phthalates (MPAEs) and sex hormones in 913 reproductive-aged women in the National Health and Nutrition Examination Survey. Key risk factors driving hormone disruption were identified based on the weights of the WQS models. Interaction models were used to unravel the synergistic or antagonistic effects between MPAEs. The potential toxicological targets of MPAEs interfering with sex hormone-binding globulin (SHBG) levels were revealed based on prior knowledge and molecular docking of hepatocyte nuclear factor 4α (HNF4α). Compared with the first quartile, mono-benzyl phthalate (MBZP) in the second quartile exhibited a decrease in total testosterone (TT) and TT/E2 (estradiol) ratio. Mono-2-ethyl-5-carboxypentyl phthalate (MECPP) in the fourth quartile showed a decrease in SHBG and TT/E2. Additionally, mono-(carboxyoctyl) phthalate and mono-(carboxynonyl) phthalate (MCNP) were negatively associated with SHBG. Each unit increase in the WQS index of MPAE mixtures was associated with 6.73 % lower SHBG levels (95 %CI: -12.80 %, -0.24 %) with mono-(3-carboxypropyl) phthalate, MCNP, MBZP, and MECPP identified as major risk factors. Interaction analyses revealed that the effects of high-risk MPAEs on SHBG were predominantly antagonistic. Molecular docking suggested that MPAEs might compete to bind tryptophan residues of HNF4α. This study provides key information to help develop the most effective phthalate interventions and improve the reproductive health of reproductive-aged women.

Associations of exposure to phthalate with serum uric acid and hyperuricemia risk, and the mediating role of systemic immune inflammation

BACKGROUND

Previous studies found that urinary phthalates (PAEs) metabolites may be associated with increased serum uric acid concentration and hyperuricemia risk. However, no population-based study has investigated the underlying biological mechanisms.

METHODS

This nationwide cross-sectional study analyzed the data from the National Health and Nutrition Examination Survey (NHANES) 2003-2018. Urinary PAEs metabolites were measured and 8 PAEs metabolites (MCPP, MECPP, MEHHP, MEOHP, MBzP, MiBP, MBP, and MEP) were incorporated into the analysis. Serum uric acid was determined and hyperuricemia cases were identified. Multi-variable generalized linear model, exposure-response (E-R) function and weighted quantile sum (WQS) regression were utilized to investigate the relationships of PAEs metabolites with serum uric acid concentration and hyperuricemia risk. Systemic immune inflammation (SII) was assessed using the SII index and its mediation effects were explored using causal mediation effect model.

RESULTS

Data from 10,633 US adults in the NHANES 2003-2018 was analyzed. Except for MEP, individual PAEs metabolite and total PAEs metabolites were associated with increased serum uric acid concentration and hyperuricemia risk. E-R function of PAEs metabolites with serum uric acid concentration and the risk of hyperuricemia showed significantly positive associations with most curves in a nearly linear relationship. WQS regression showed that the mixture of PAEs metabolites was related to elevated serum uric acid and hyperuricemia risk, and MBzP was identified as the most contributing PAEs metabolite. The causal mediation effect model found that SII significantly mediated the relationships of PAEs metabolites with serum uric acid and hyperuricemia risk.

CONCLUSION

Individual and mixture of urinary PAEs metabolites were associated with increased serum uric acid concentration and the risk of hyperuricemia. MBzP exhibited the highest contribution to the overall effects. SII alteration may be an important biological mechanism underlining the impact of PAEs metabolites on serum uric acid concentration and hyperuricemia risk.

Clinical relevance of urinary 8‑hydroxydeoxyguanosine levels in patients undergoing prostate biopsy

Urinary 8-hydroxydeoxyguanosine (8-OHdG) level is an oxidative stress marker in patients with cancer; however, little is currently known about the clinical relevance of urinary 8-OHdG levels in patients with prostate cancer at diagnosis. Voided urine samples were collected from patients at the time of prostate biopsy and stored at -80˚C after centrifugation. All of the patients were classified according to histology of the biopsy. Once the patients were diagnosed with prostate cancer, the standard of care and treatments were administered according to the standard guidelines. The association between clinicopathological parameters and urinary 8-OHdG and N-terminal telopeptide (NTx) levels were explored. A total of 409 patients received prostate biopsy, of which 190 were benign, 41 were diagnosed with prostatitis and 178 were diagnosed with prostate cancer. The urinary 8-OHdG/creatinine ratio was marginally associated with prostate size (P=0.052) but not with serum prostate-specific antigen levels (P=0.707). With correction for prostate size, the ratio of urinary 8-OHdG/creatinine was significantly higher in patients with prostate cancer than those without malignancy (P=0.004). Moreover, urinary 8-OHdG levels were weakly associated with urinary NTx levels (r2=0.04, P=0.009). In conclusion, urinary 8-OHdG levels normalized for prostate volume may reflect prostate cancer risk and could be used to predict prostate cancer aggressiveness.

Antioxidant vitamins' modification of the adverse health effects induced by phthalate exposure: A scoping review of epidemiological and experimental studies

The exposure to and health hazards of phthalates have received abundant attention. However, reducing phthalate exposure and further decreasing the associated health risks are difficult. Nonetheless, it is important to actively seek relevant measures. Recently, antioxidant vitamins have been frequently mentioned to improve phthalate-related issues. This scoping review summarizes the existing epidemiological and experimental studies on the interaction of phthalates with antioxidant vitamins. Through a systematic search, sparse epidemiological studies explored the effects of interaction between phthalates and vitamins on reproduction, the endocrine, respiratory, and nervous system and human aging. Four prospective studies were conducted in China, the United States, Canada and Netherlands. Only one study from Netherlands focused on the female reproductive system.The other three studies focused on neurological damage to fetuses caused by phthalate exposure, and its mitigation by vitamin supplementation during pregnancy. Four cross-sectional studies were conducted based on the United States National Health and Nutrition Examination Survey database. These studies involved hazards in different systems and interactions with different vitamins. Overall, epidemiological evidence suggests that antioxidant vitamins such as vitamin A, B, D, and folic acid probably may alter the health hazards induced by phthalate exposure. Current animal studies often focus on three phthalates, DBP, DEHP and DIDP,2 and most commonly, the first two phthalates. These chemicals cause reproductive, urinary, digestive and neurodevelopmental damage; the antioxidant vitamin C, E and B could mitigate the harm caused by phthalates. Possible mechanisms involve reducing oxidative stress, removing methylation,etc. Determining whether these mechanisms are similar to those in humans requires a rigorous experimental study.

Machine Learning Models for Predicting Bioavailability of Traditional and Emerging Aromatic Contaminants in Plant Roots

To predict the behavior of aromatic contaminants (ACs) in complex soil-plant systems, this study developed machine learning (ML) models to estimate the root concentration factor (RCF) of both traditional (e.g., polycyclic aromatic hydrocarbons, polychlorinated biphenyls) and emerging ACs (e.g., phthalate acid esters, aryl organophosphate esters). Four ML algorithms were employed, trained on a unified RCF dataset comprising 878 data points, covering 6 features of soil-plant cultivation systems and 98 molecular descriptors of 55 chemicals, including 29 emerging ACs. The gradient-boosted regression tree (GBRT) model demonstrated strong predictive performance, with a coefficient of determination (R2) of 0.75, a mean absolute error (MAE) of 0.11, and a root mean square error (RMSE) of 0.22, as validated by five-fold cross-validation. Multiple explanatory analyses highlighted the significance of soil organic matter (SOM), plant protein and lipid content, exposure time, and molecular descriptors related to electronegativity distribution pattern (GATS8e) and double-ring structure (fr_bicyclic). An increase in SOM was found to decrease the overall RCF, while other variables showed strong correlations within specific ranges. This GBRT model provides an important tool for assessing the environmental behaviors of ACs in soil-plant systems, thereby supporting further investigations into their ecological and human exposure risks.

Impact of polyethylene microplastics exposure on kallikrein-3 levels, steroidal-thyroidal hormones, and antioxidant status in murine model: protective potentials of naringin

The widespread presence of microplastics in the environment has raised significant concerns regarding their potential impact on human and animal health. Among various microplastic types, polyethylene microplastics (PE-MPs) are particularly prevalent due to the extensive use in packaging and consumer products. Exploring the uncharted therapeutic potentials of naringin, this study delves into its mitigating effects on disruptions in kallikrein-3 levels, steroidal-thyroidal hormone balance, and antioxidant defense triggered by PE-MPs exposure, paving the way for novel interventions in environmental toxin-induced endocrine and oxidative stress disorders. Male Wistar rats (n = 24) were randomly grouped into four: Control, PE-MPs (1.5 mg/kg), PE-MPs + NAR (1.5 mg/kg PE-MPs + 100 mg/kg NAR), and NAR (100 mg/kg). Hormonal and antioxidant parameters were assessed after 28 days of exposure. PE-MPs exposure caused a significant increase(p < 0.005) in the level of kallikrein-3 (KLK-3) while it significantly reduces the levels of testosterone (TST), luteinizing hormone, thyroid stimulating hormone (TSH) and Free-triiodothyronine (fT3) and Total cholesterol (TChol) concentration. PE-MPs exposure also disrupted significantly (p < 0.005) antioxidant profile by down-regulating the activities of glutathione-S-transferase, catalase (CAT), superoxide dismutase (SOD) and reducing levels of glutathione (GSH) and ascorbic acid (AA) while concentration of malondialdehyde (MDA) levels were increased relative to control. However, the mitigating potentials of naringin on disruptions in hormonal and antioxidant profiles caused by PE-MPs exposure were demonstrated, as NAR normalized KLK-3, steroid, and thyroid hormone levels, cholesterol concentration, and enhanced antioxidant defense. This suggests that NAR is a promising protective agent against endocrine and oxidative damage induced by environmental contaminants such as microplastics.

Mono-2-ethylhexyl phthalate-induced downregulation of MMP11 in foreskin fibroblasts contributes to the pathogenesis of hypospadias

Hypospadias is one of the most common congenital anomalies of the male urogenital system, and di(2-ethylhexyl) phthalate (DEHP), a widely used endocrine-disrupting chemical (EDC), is considered a significant risk factor for this condition. Mono-2-ethylhexyl phthalate (MEHP), the toxic active metabolite of DEHP, has been proven to affect penile development and ultimately result in the hypospadias phenotype. However, while it is acknowledged that hypospadias arises from the aberrant development of multiple penile tissues, the specific impact of MEHP on human foreskin tissue development and its underlying molecular mechanisms of action remain unclear. In this study, we constructed an in vitro toxicity assay for MEHP using human foreskin fibroblasts and employed high-throughput RNA sequencing to investigate the molecular mechanisms subserving the defects in cellular function. We subsequently conducted multi-omics data analysis using public databases to analyze key target genes, and identified MMP11 as a chief downstream gene responsible for the effects of MEHP on HFF-1 cell migration. Through molecular docking analysis and molecular biology experiments, we further demonstrated that the nuclear receptor PPAR-gamma was activated upon binding with MEHP, leading to the suppression of MMP11 expression. Additionally, we found that epigenetic modifications induced by MEHP were also involved in its pathogenic effects on hypospadias. Our research highlights the crucial role of impaired cellular proliferation and migration in MEHP-induced hypospadias. We identified the MEHP/PPAR-gamma/MMP11 pathway as a novel pathogenic mechanism, providing important potential targets for future preventive strategies with respect to hypospadias.

Impacts of Environmental Concentrations of Nanoplastics on Zebrafish Neurobehavior and Reproductive Toxicity

Nanoplastics, as emerging environmental pollutants, can transport contaminants across marine environments, polluting pristine ecosystems and being ingested by marine organisms. This transfer poses a severe threat to global aquatic ecosystems and potentially impacts human health through the food chain. Neurobehavioral and reproductive toxicity are critical areas of concern because they directly affect the survival, health, and population dynamics of aquatic species, which can have cascading effects on the entire ecosystem. Using zebrafish as a model organism, we investigated the toxic effects of environmental concentrations of polystyrene nanoplastics (PS-NPs). Behavioral assessments, including the novel tank test and open field test, demonstrated significant neurobehavioral changes, indicating increased anxiety and depressive behaviors. A pathological analysis of brain and gonadal tissues, along with evaluations of neurobehavioral and reproductive toxicity biomarkers, revealed that exposure to PS-NPs leads to brain tissue lesions, inflammatory responses, oxidative stress activation, hormone level disruptions, and gonadal damage. Real-time quantitative PCR studies of reproductive gene expression further showed that PS-NPs disrupt the endocrine regulation pathways of the brain-pituitary-gonadal (BPG) axis, causing reproductive toxicity with sex-specific differences. These findings provide crucial insights into the impacts of nanoplastics on aquatic organisms and their ecological risks, offering theoretical support for future environmental protection and pollutant management efforts.

ExpoNano: A Strategy Based on Hyper-Cross-Linked Polymers Achieves Urinary Exposome Assessment for Biomonitoring

Urinary analysis of exogenous and endogenous molecules constitutes an efficient, noninvasive approach to evaluate human health status. However, the exposome characterization of urinary molecules remains extremely challenging with current techniques. Herein, we develop an ExpoNano strategy based on hyper-cross-linked polymers (HCPs) to achieve ultrahigh-throughput measurement of exo/endogenous molecules in urine. The strategy includes a simple trapping-detrapping procedure (15 min) with HCPs in enzymatically treated urine, followed by mass spectrometer determination. Molecules that can be determined by ExpoNano have a wide range of molecular weight (75-837 Da) and Log Kow (octanol-water partition coefficient; -9.86 to 10.56). The HCPs can be repeatedly used five times without decreasing the trapping efficiency. Application of ExpoNano in a biomonitoring study revealed a total of 63 environmental chemicals detected in >50% of the urine pools collected from Chinese adults living in 13 cities, with a median concentration of 0.026-47 ng/mL, while nontargeted analysis detected an additional 243 exogenous molecules. Targeted and nontargeted analysis also detected 926 endogenous molecules in pooled urine. Collectively, the ExpoNano strategy demonstrates unique advantages over traditional urine analysis approaches, including a wide range of analytes, satisfactory trapping efficiency, high simplicity and reusability, and extremely reduced time demand and financial cost.

Bmal1 regulates female reproduction in mice via the hypothalamic-pituitary-ovarian axis

The hypothalamic-pituitary-gonadal axis (HPG) is the key neuroendocrine axis involved in reproductive regulation. Brain and muscle ARNT-like protein 1 (Bmal1) participates in regulating the metabolism of various endocrine hormones. However, the regulation of Bmal1 on HPG and female fertility is unclear. This study aims to explore the regulation of female reproduction by Bmal1 via the HPG axis in mice. Bmal1-knockout (Ko) mice were generated using the CRISPR/Cas9 technology. The structure, function, and estrous cycle of ovarian in Bmal1 Ko female mice were measured. The key genes and proteins of the HPG axis involved in regulating female reproduction were examined through transcriptome analysis and then verified by RT-PCR, immunohistochemistry, and western blot. Furthermore, the fertility of female mice was detected after intervening prolactin (PRL) and progesterone (Pg) in Bmal1 ko mice. The number of offspring and ovarian weight were significantly lower in Bmal1-Ko mice than in wild-type (Wt) mice. In Bmal1-Ko mice, ovarian cells were arranged loosely and irregularly, and the total number of follicles was significantly reduced. No corpus luteum was found in the ovaries. Vaginal smears revealed that Bmal1-Ko mice had an irregular estrus cycle. In Bmal1-Ko mice, Star expression was decreased, PRL and luteinizing hormone (LH) levels were increased, and dopamine (DA) and Pg levels were decreased. Inhibition of PRL partially recovered the estrous cycle, corpus luteum formation, and Star expression in the ovaries. Pg supplementation promoted embryo implantation in Bmal1-Ko female mice. Bmal1 Ko increases serum PRL levels in female mice likely by reducing DA levels, thus affecting luteal formation, resulting in decreased Star expression and Pg production, hindering female reproduction. Inhibition of PRL or restoration of Pg can partially restore reproductive capacity in female Bmal1-Ko mice. Thus, Bmal1 may regulate female reproduction via the HPG axis in mice, suggesting that Bmal1 is a potential target to treat female infertility.

Gender-specific effects of polystyrene nanoplastic exposure on triclosan-induced reproductive toxicity in zebrafish (Danio rerio)

Nanoplastics (NPs) and triclosan (TCS) are ubiquitous emerging environmental contaminants detected in human samples. While the reproductive toxicity of TCS alone has been studied, its combined effects with NPs remain unclear. Herein, we employed Fourier transform infrared spectroscopy and dynamic light scattering to characterize the coexposure of polystyrene nanoplastics (PS-NPs, 50 nm) with TCS. Then, adult zebrafish were exposed to TCS at environmentally relevant concentrations (0.361-48.2 μg/L), with or without PS-NPs (1.0 mg/L) for 21 days. TCS biodistribution in zebrafish tissues was investigated using ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry. Reproductive toxicity was assessed through gonadal histopathology, fertility tests, changes in steroid hormone synthesis and gene expression within the hypothalamus-pituitary-gonad-liver (HPGL) axis. Transcriptomics and proteomics were applied to explore the underlying mechanisms. The results showed that PS-NPs could adsorb TCS, thus altering the PS-NPs' physical characteristics. Our observations revealed that coexposure with PS-NPs reduced TCS levels in the ovaries, livers, and brains of female zebrafish. Conversely, in males, coexposure with PS-NPs increased TCS levels in the testes and livers, while decreasing them in the brain. We found that co-exposure mitigated TCS-induced ovary development inhibition while exacerbated TCS-induced spermatogenesis suppression, resulting in increased embryonic mortality and larval malformations. This co-exposure influenced the expression of genes linked to steroid hormone synthesis (cyp11a1, hsd17β, cyp19a1) and attenuated the TCS-decreased estradiol (E2) in females. Conversely, testosterone levels were suppressed, and E2 levels were elevated due to the upregulation of specific genes (cyp11a1, hsd3β, cyp19a1) in males. Finally, the integrated analysis of transcriptomics and proteomics suggested that the aqp12-dctn2 pathway was involved in PS-NPs' attenuation of TCS-induced reproductive toxicity in females, while the pck2-katnal1 pathway played a role in PS-NPs' exacerbation of TCS-induced reproductive toxicity in males. Collectively, PS-NPs altered TCS-induced reproductive toxicity by disrupting the HPGL axis, with gender-specific effects.

Oxidative damage to mitochondrial DNA in maternal zebrafish (Danio rerio) exposed to dibutyl phthalate at environmentally relevant level

Dibutyl phthalate (DBP) is a widely-used plasticizer that is dispersed in various environments, causing significant pollution and health risks. The toxic mechanism of DBP has been discussed in recent years, while the susceptibility of mitochondrial DNA (mtDNA) to DBP exposure and the resulting damage remain unclear. In this study, maternal zebrafish were exposed to environmentally relevant concentration of DBP for 0, 2, 4, and 6 weeks. Results showed that DBP exposure impaired health status, leading to the reduced body length and weight, condition factor, hepatosomatic index, and gonadosomatic index. Furthermore, DBP exposure induced oxidative stress and ATP deficiency in the gill and liver in a time-dependent manner. The oxidized mtDNA (ox-mtDNA) levels in the D-loop and ND1 regions were assessed in different tissues, showing distinct response patterns. The high energy-consuming tissues such as heart, brain, gill, and liver exhibited elevated susceptibility to mitochondrial damage, with a rapid increase in ox-mtDNA levels in the short term. Conversely, in muscle, ovary, eggs, and offspring, ox-mtDNA gradually accumulated over the exposure period. Notably, the ox-mtDNA levels in the D-loop region of blood showed a prompt response to DBP exposure, making it convenient for evaluation. Additionally, decreased hatching rates, increased mortality, lipoperoxidation, and depressed swimming performance were observed in offspring following maternal DBP exposure, suggesting the inherited impairments of maternal mtDNA. These findings highlight the potential for ox-mtDNA to serve as a convenient biomarker for environmental contamination, aiding in ecological risk assessment and forewarning systems in aquatic environment.

Study on the mechanism and degradation behavior of Encifer adhaerens DNM-S1 capturing dimethyl phthalate

The global concern surrounding pollution caused by phthalates is escalating, with dimethyl phthalate (DMP) emerging as one of the most prevalent contaminants within the phthalates (PAEs) category. Although the biodegradation of DMP is considered both safe and efficient, its underlying degradation mechanism is not yet fully elucidated, and the degradation performance can be somewhat inconsistent. To address this issue, our study isolated a DMP-degrading bacterium (DNM-S1) from a vegetable greenhouse. The resulting data revealed that DNM-S1 exhibited a remarkable degradation performance, successfully degrading 84.98% of a 2000 mg L-1 DMP solution within 72 h. Remarkably, it achieved complete degradation of a 50 mg L-1 DMP solution within just 3 h. DMP degradation by DNM-S1 was also found to be efficient even under low-temperature conditions (10 °C). Our research further indicates that DNM-S1 is capable of capturing DMP through the ester bond in the bacterium's cell wall fatty acids, forming hydrogen bonds through hydrophobic interactions. The DMP was then transported into the DNM-S1 protoplasm using an active transport mechanism. Interestingly, the secondary metabolites of DNM-S1 contained natural carotenoids, which could potentially counteract the damaging effects of PAEs on cell membrane permeability. In summary, these findings highlight the potential of DNM-S1 in addressing PAEs pollution and provide new insights into the metabolic mechanism of PAEs degradation.

Fabrication of Magnetic Molecularly Imprinted Polymers for Selective Extraction of Dibutyl Phthalates in Food Matrices

In this study, a novel magnetic molecularly imprinted polymeric material (Fe3O4@MOF@MIP-160) with a metal-organic backbone (Fe3O4@MOF) carrier was prepared using dibutyl phthalate (DBP) as a template. The material can be used for the efficient, rapid, and selective extraction of trace amounts of phthalic acid esters (PAEs) in food and can detect them via gas chromatography-mass spectrometry (GC-MS). The synthesis conditions of the materials were optimized to prepare the Fe3O4@MOF@MIP160 with the highest adsorption performance. Transmission electron microscopy (TEM), Fourier Transform Infrared Spectra (FT-IR), Vibration Sample Magnetic (VSM), and the Brunauer-Emmett-Teller (BET) method were used to characterize the materials. Compared with Fe3O4@MOF and the magnetic non-imprinted polymeric material (Fe3O4@MOF@NIP), Fe3O4@MOF@MIP-160 possesses the advantages of easy and rapid manipulation of magnetic materials, the advantages of high specific surface area and the stability of metal-organic frameworks, and the advantages of high selectivity of molecularly imprinted polymers. Fe3O4@MOF@MIP-160 has good recognition and adsorption capacity for di-butyl phthalate (DBP) and diethylhexyl phthalate (DEHP): the adsorption capacity for DBP and DEHP is 260 mg·g-1 and 240.2 mg·g-1, and the adsorption rate is fast (reaching equilibrium in about 20 min). Additionally, Fe3O4@MOF@MIP160 could be recycled six times, making it cost-effective, easy to operate, and time-saving as compared to traditional solid-phase extraction materials. The phthalate ester content in drinking water, fruit juice, and white wine was analyzed, with recoveries ranging from 70.3% to 100.7%. This proved that Fe3O4@MOF@MIP160 was suitable for detecting and removing PAEs from food matrices.

Vitamin D Deficiency Exacerbates Poor Sleep Outcomes with Endocrine-Disrupting Chemicals Exposure: A Large American Population Study

Phthalates and bisphenol A are recognized as the predominant endocrine-disrupting substances (EDCs) in the environment, but their impact on sleep health remains unclear. Vitamin D has often been reported to play a role in sleep health and may be affected by endocrine-disrupting compounds. The study utilized data from 5476 individuals in the NHANES project to investigate the correlation between combined exposure to environmental EDCs and sleep duration through modeling various exposures. Furthermore, it emphasizes the importance of vitamin D in the present scenario. Preliminary analyses suggested that vitamin D-deficient individuals generally slept shorter than individuals with normal vitamin D (p < 0.05). Exposure to Mono-ethyl phthalate (MEP), triclosan (TRS), and Mono-benzyl phthalate (MZP), either alone or in combination, was associated with reduced sleep duration and a greater risk of vitamin D deficiency. Individuals with low vitamin D levels exposed to TRS experienced shorter sleep duration than those with normal vitamin D levels (p < 0.05). TRS and MZP were identified as crucial factors in patient outcomes when evaluating mixed exposures (p < 0.05). The results provide new data supporting a link between exposure to EDCs and insufficient sleep length. Additionally, they imply that a vitamin D shortage may worsen the sleep problems induced by EDCs.

Advances in understanding the reproductive toxicity of endocrine-disrupting chemicals in women

Recently, there has been a noticeable increase in disorders of the female reproductive system, accompanied by a rise in adverse pregnancy outcomes. This trend is increasingly being linked to environmental pollution, particularly through the lens of Endocrine Disrupting Chemicals (EDCs). These external agents disrupt natural processes of hormones, including synthesis, metabolism, secretion, transport, binding, as well as elimination. These disruptions can significantly impair human reproductive functions. A wealth of animal studies and epidemiological research indicates that exposure to toxic environmental factors can interfere with the endocrine system's normal functioning, resulting in negative reproductive outcomes. However, the mechanisms of these adverse effects are largely unknown. This work reviews the reproductive toxicity of five major environmental EDCs-Bisphenol A (BPA), Phthalates (PAEs), Triclocarban Triclosan and Disinfection Byproducts (DBPs)-to lay a foundational theoretical basis for further toxicological study of EDCs. Additionally, it aims to spark advancements in the prevention and treatment of female reproductive toxicity caused by these chemicals.

Ca2+ homeostasis imbalance induced by Pparg: A key factor in di (2-ethylhexyl) phthalate (DEHP)-induced cardiac dysfunction in zebrafish larvae

Widespread application of the typical phthalate plasticizers, di (2-ethylhexyl) phthalate (DEHP), poses a serious potential threat to the health of animals and even humans. Previous studies have confirmed the mechanism of DEHP-induced cardiac developmental defects in zebrafish larvae. However, the mechanism of cardiac dysfunction is still unclear. Thus, this work aimed to comprehensively investigate the mechanisms involved in DEHP-induced cardiac dysfunction through computational simulations, in vivo assays in zebrafish, and in vitro assays in cardiomyocytes. Firstly, molecular docking and western blot initially investigated the activating effect of DEHP on Pparg in zebrafish. Although GW9662 (PPARG antagonist) effectively alleviated DEHP-induced cardiac dysfunction and lipid metabolism disorders, it did not restore significant decreases in mitochondrial membrane potential and ATP levels. In vitro assays in cardiomyocytes, DEHP caused overexpression of PPARG and proteins involved in the regulation of Ca2+ homeostasis, and the above abnormalities were effectively alleviated by GW9662, suggesting that the Ca2+ homeostatic imbalance caused by activation of PPARG by DEHP seems to be the main cause of DEHP-induced cardiac dysfunction. To sum up, this work not only refines the mechanism of toxic effects of cardiotoxicity induced by DEHP, but provides an important theoretical basis for enriching the toxicological effects of DEHP.

Prenatal phthalate exposure and sex steroid hormones in newborns: Taiwan Maternal and Infant Cohort Study

BACKGROUND

Newborn anogenital distance (AGD) has been associated with prenatal exposure of phthalates. The association between prenatal phthalate exposure and sex steroid hormones in newborns is unclear.

OBJECT

This study aimed to examine whether cord-blood sex hormone levels were associated with prenatal phthalate exposure and newborn anogenital distance (AGD).

METHODS

In the Taiwan Maternal and Infant Cohort Study, we recruited 1,676 pregnant women in their third trimester in 2012-2015 in Taiwan. We determined 11 urinary phthalate metabolites in pregnant women, three maternal and five cord-blood steroid sex-hormone concentrations. Five hundred and sixty-five mother-infant pairs with sufficient data were included. Trained neonatologists measured 263 newborns' AGD. We examined the associations of prenatal phthalate metabolite levels with AGD and hormones using linear regression models and evaluated correlations between maternal and cord-blood sex hormone levels and AGD.

RESULTS

Compared with the male newborns exposed to maternal phthalate metabolites at the first tertile, AGD was -3.75, -3.43, and -3.53 mm shorter among those exposed at the median tertile of di-2-ethylhexyl phthalate (DEHP) metabolites, monobenzyl phthalate (MBzP), and monomethyl phthalate (MMP), respectively. Compared with those who had exposed at the first tertile, cord-blood follicle-stimulating hormone (FSH) decreased among male newborns exposed at higher levels of MMP, mono-n-butyl phthalate (MnBP), MBzP and DEHP, and among female newborns exposed at higher levels of MMP, MBzP and mono(2-ethyl-5-hydroxyhexyl) phthalate. However, we did not observe significant correlations of maternal or cord-blood sex steroid hormones with newborns' AGDs.

CONCLUSIONS

Alterations in cord-blood sex steroid hormone levels were associated with prenatal phthalate exposures, particularly in male newborns. Women aspiring to be pregnant should be alerted of the need of reducing phthalate exposure.

Phthalate metabolites and sex steroid hormones in relation to obesity in US adults: NHANES 2013-2016

Background

Obesity and metabolic syndrome pose significant health challenges in the United States (US), with connections to disruptions in sex hormone regulation. The increasing prevalence of obesity and metabolic syndrome might be associated with exposure to phthalates (PAEs). Further exploration of the impact of PAEs on obesity is crucial, particularly from a sex hormone perspective.

Methods

A total of 7780 adult participants in the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2016 were included in the study. Principal component analysis (PCA) coupled with multinomial logistic regression was employed to elucidate the association between urinary PAEs metabolite concentrations and the likelihood of obesity. Weighted quartiles sum (WQS) regression was utilized to consolidate the impact of mixed PAEs exposure on sex hormone levels (total testosterone (TT), estradiol and sex hormone-binding globulin (SHBG)). We also delved into machine learning models to accurately discern obesity status and identify the key variables contributing most to these models.

Results

Principal Component 1 (PC1), characterized by mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) as major contributors, exhibited a negative association with obesity. Conversely, PC2, with monocarboxyononyl phthalate (MCNP), monocarboxyoctyl phthalate (MCOP), and mono(3-carboxypropyl) phthalate (MCPP) as major contributors, showed a positive association with obesity. Mixed exposure to PAEs was associated with decreased TT levels and increased estradiol and SHBG. During the exploration of the interrelations among obesity, sex hormones, and PAEs, models based on Random Forest (RF) and eXtreme Gradient Boosting (XGBoost) algorithms demonstrated the best classification efficacy. In both models, sex hormones exhibited the highest variable importance, and certain phthalate metabolites made significant contributions to the model's performance.

Conclusions

Individuals with obesity exhibit lower levels of TT and SHBG, accompanied by elevated estradiol levels. Exposure to PAEs disrupts sex hormone levels, contributing to an increased risk of obesity in US adults. In the exploration of the interrelationships among these three factors, the RF and XGBoost algorithm models demonstrated superior performance, with sex hormones displaying higher variable importance.

A high-affinity fluorescent probe for human uridine-disphosphate glucuronosyltransferase 1A9 function monitoring under environmental pollutant exposure

Uridine-disphosphate glucuronosyltransferase 1A9 (UGT1A9), an important detoxification and inactivation enzyme for toxicants, regulates the exposure level of environmental pollutants in the human body and induces various toxicological consequences. However, an effective tool for high-throughput monitoring of UGT1A9 function under exposure to environmental pollutants is still lacking. In this study, 1,3-dichloro-7-hydroxy-9,9-dimethylacridin-2(9H)-one (DDAO) was found to exhibit excellent specificity and high affinity towards human UGT1A9. Remarkable changes in absorption and fluorescence signals after reacting with UGT1A9 were observed, due to the intramolecular charge transfer (ICT) mechanism. Importantly, DDAO was successfully applied to monitor the biological functions of UGT1A9 in response to environmental pollutant exposure not only in microsome samples, but also in living cells by using a high-throughput screening method. Meanwhile, the identified pollutants that disturb UGT1A9 functions were found to significantly influence the exposure level and retention time of bisphenol S/bisphenol A in living cells. Furthermore, the molecular mechanism underlying the inhibition of UGT1A9 by these pollutant-derived disruptors was elucidated by molecular docking and molecular dynamics simulations. Collectively, a fluorescent probe to characterize the responses of UGT1A9 towards environmental pollutants was developed, which was beneficial for elucidating the health hazards of environmental pollutants from a new perspective.

Are the new phthalates safe? Evaluation of Diisononilphtalate (DINP) effects in porcine ovarian cell cultures

Phthalates are plasticizing chemicals, widely used in packaging materials and consumer products for several decades. These molecules have raised concerns because of their toxicity and their use have been restricted in several countries. Therefore, novel phthalates have been introduced. Among these, diisononilphtalate (DINP) is widely employed. However, its safety has not been properly addressed. Therefore, using a well validated granulosa cell model, collected from swine ovaries with a translational value, we studied potential DINP effects on important cellular functional parameters. In particular, we studied cell growth, steroidogenesis and redox status. Collected data showed that DINP stimulates (p < 0.05) cell growth, increases estrogen and inhibits progesterone production (p < 0.05), disrupts redox balance stimulating free radicals (p < 0.05) while reducing scavenger activities (p< 0.05). Taken together, DINP's impact on cultured swine granulosa cells provides cause for concern regarding its potential adverse effects on reproductive and endocrine functions.