Organophosphate Flame Retardants in Pregnant Women: Sources, Occurrence, and Potential Risks to Pregnancy Outcomes

Simultaneous determination of multiple endocrine disrupting chemicals in human amniotic fluid samples by solid phase extraction coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS)

Prenatal exposure to endocrine-disrupting chemicals (EDCs) may lead to immediate and long-term adverse health effects in the offspring. The occurrence levels of EDCs in amniotic fluid (AF) have significant influence on fetus prior to birth. In this study, an analytical method for simultaneous determination of a total of 59 widely concerned EDCs, including 11 bisphenols (BPs), 4 parabens, 11 phthalate metabolites (mPAEs), 7 organophosphate metabolites (mOPEs), 8 polycyclic aromatic hydrocarbons metabolites (OH-PAHs) and 18 perfluorinated compounds (PFASs), in human AF samples was developed employing solid phase extraction (SPE) coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS). Key parameters of SPE procedures were carefully investigated. The developed method enabled the determination of 59 EDCs in a low sample volume (500 μL) with LOD and LOQ values in the range of 0.02-0.2 ng/mL and 0.07-0.66 ng/mL, respectively. The recoveries (60.95 %-144.74 %) and precisions (<44 %) were obtained. To further verify the method, AF samples from Tianjin of China were collected and analyzed. The detected concentrations of BPs, parabens, mPAEs, mOsPEs, and PFASs ranged from < LOD-60.48 ng/mL, indicating satisfying performance for field samples. Furthermore, the results of AGREEprep, ComplexGAPI and BAGI exhibited good environmental friendliness and applicability of the developed method.

Association of organophosphate flame retardants exposure with liver function and the contrasting mediating roles of inflammatory and oxidative stress pathways

Organophosphate flame retardants (OPFRs) have been widely used as alternatives to traditional halogenated flame retardants, resulting in their pervasive environmental presence and significant human exposure. While animal studies using high doses of individual OPFRs have demonstrated hepatotoxicity, evidence of hepatic effects from chronic and low-dose exposure to OPFRs in humans is scarce, and the underlying mechanisms remain largely unknown. In this study, we evaluated the association between urinary metabolites of OPFRs (mOPFRs) and liver function biomarkers in a population aged 1-79 years from the Guangzhou Human Biomonitoring Program. Urinary concentrations of diphenyl phosphate exhibited a significant decreasing trend with increasing age across four age groups (≤12, 13-17, 17-59, ≥60 years), while bis(1-chloro-2-propyl) phosphate concentrations showed a significant positive association with age. Urinary mOPFRs were positively associated with alanine aminotransferase, gamma-glutamyl transferase, and aspartate aminotransferase, and negatively associated with indirect bilirubin levels. Urinary mOPFRs were significantly correlated with total bilirubin, which was consistent with that observed in the National Health and Nutrition Examination Survey database, while other associations were inconsistent. Moreover, we evaluated the roles of inflammatory and oxidative stress markers in the association between urinary mOPFRs and liver function biomarkers by mediation analysis. The results demonstrated that the mediation effects of inflammatory markers were consistent with the total and direct effects of mOPFRs on liver function biomarkers, whereas the mediation effects of oxidative stress markers were discrepant. Inflammation likely exacerbates the adverse effects of OPFRs on liver function, while oxidative stress may play a protective role. We further searched the comparative toxicogenomics database for genes associated with OPFRs and liver function biomarkers to understand the potential regulatory mechanisms.

Traditional and novel organophosphate esters in atmosphere of greenhouse covered with mulch films: Seasonal variations, partitioning and exposure risks

Mulch films play a critical role in the accumulation of organophosphate esters (OPEs) in greenhouse soils. However, their impact on the occurrence, partitioning and health risks of atmospheric OPEs is unclear. This study fully investigated multi-media distributions of eleven traditional OPEs and four novel OPEs in greenhouses covered with degradable mulch films. The atmospheric concentrations exhibited substantial variability, ranging from 539 to 14821 pg/m³ in the gas phase and from 242 to 8320 pg/m³ in the particle phase, with summer levels higher than winter levels. Significant correlations (p < 0.05) were detected between OPE concentrations in mulch films and in air, indicating mulch films as a major source. First-order kinetic model effectively characterized the release patterns of dominant congeners including triphenyl phosphate and tris(2,4-ditert-butylphenyl) phosphate from degradable films. The Li-Ma-Yang model showed superior predictive capability for gas-particle partitioning than the Harner-Bidleman model. Total concentrations of OPEs in uncoated soils were at a range of 274-955 μg/kg. Soil-air exchange behaviors of OPEs governed by inherent volatility exhibited a seasonal dependence. While non-carcinogenic risks of OPEs for greenhouse farmers via air inhalation and dermal contact were negligible, holistic health assessments should integrate other uptake pathways and consider transformation products of OPEs.

Gestational exposures to mixtures of multiple chemical classes and autism spectrum disorder in the MARBLES study

BACKGROUND

Previous epidemiologic studies on gestational chemical exposures and autism spectrum disorder (ASD) often lack analysis of chemical mixtures or are limited to investigating certain chemical classes.

OBJECTIVE

We examined the impact of multi-class chemical mixtures on ASD risk, using data from the MARBLES (Markers of Autism Risks in Babies-Learning Early Signs) cohort.

METHODS

Children were clinically assessed at age 3 and classified as ASD, typical development (TD), or non-TD with other neurodevelopmental concerns. In blood or urine from 105 pregnant mothers, we quantified 42 biomarkers across 5 chemical classes: per- and polyfluoroalkyl substances (PFAS), parabens, phenols, phthalates, and organophosphate esters (OPEs). We only analyzed 30 biomarkers detected in >50 % of the sample. After identifying clusters with similar chemical profiles via hierarchical clustering, we applied linear discriminant analysis (LDA) to compute LDA exposure summary scores. In covariate-adjusted models, we used LDA scores to assess co-adjusted, multipollutant associations (relative risk [RR]) with ASD or non-TD, via quasi-Poisson regression. We further examined overall mixture effect and chemical interactions with Bayesian kernel machine regression.

RESULTS

We identified four distinct clusters: PFAS (Cluster 1), OPEs (Cluster 2), parabens and triclosan (Cluster 3), and phthalates and bisphenol A (Cluster 4). Relative to TD, LDA scores for each cluster were associated with increased risk of ASD (RR [95 % CI]: 1.14 [1.03, 1.25], 1.12 [1.01, 1.24], 1.17 [1.07, 1.29], 1.17 [1.07, 1.28] for Cluster 1-4, respectively), whereas clusters 2 and 4 were associated with non-TD (1.07 [1.01, 1.14] and 1.12 [1.05, 1.19], respectively). Cumulative exposure across the four clusters was linked to increased risk of both ASD and non-TD. Potential interactions within and between clusters were observed.

CONCLUSION

This study shows that considering multiple chemical classes resulted in stronger associations with ASD and non-TD risk, compared to when investigated separately in our previous studies.

Artificial Intelligence for the Discovery of Safe and Effective Flame Retardants

Organophosphorus flame retardants (OPFRs) are important chemical additives that are used in commercial products. However, owing to increasing health concerns, the discovery of new OPFRs has become imperative. Herein, we propose an explainable artificial intelligence-assisted product design (AIPD) methodological framework for screening novel, safe, and effective OPFRs. Using a deep neural network, we established a flame retardancy prediction model with an accuracy of 0.90. Employing the SHapley Additive exPlanations approach, we have identified the Morgan 507 (P═N connected to a benzene ring) and 114 (quaternary carbon) substructures as promoting units in flame retardancy. Subsequently, approximately 600 compounds were selected as OPFR candidates from the ZINC database. Further refinement was achieved through a comprehensive scoring system that incorporated absorption, toxicity, and persistence, thereby yielding six prospective candidates. We experimentally validated these candidates and identified compound Z2 as a promising candidate, which was not toxic to zebrafish embryos. Our methodological framework leverages AIPD to effectively guide the discovery of novel flame retardants, significantly reducing both developmental time and costs.

Analogue-Specific Transplacental Transfer of Organophosphate Flame Retardants in ICR Mouse Mediated by Active Transport

Prenatal exposure to organophosphate flame retardants (OPFRs) may pose potential health risks to offspring. While prior studies have demonstrated that OPFRs can be transferred from mothers to fetuses, the mechanism underlying transplacental transfer remains unclear. The pregnant ICR mouse and JAR cell (a monolayer model), in combination with molecular docking, were used to explore the underlying mechanism. OPFRs were rapidly metabolized into diester metabolites following oral gavage in the ICR mouse, with considerable concentrations detected in maternal serum, amniotic fluid, and placenta, as well as fetus within 3 h. After 6 h, the accumulation ratios of OPFRs between the mother and fetus exhibited a parabolic relationship with log KOW. Oral exposure resulted in a decrease in interstitial cells in the decidua and an expansion of vascular systems in the labyrinthine area. RT-qPCR analysis revealed upregulated expression levels of transporter mRNA in the placenta, suggesting a protective mechanism characterized by greater efflux than influx transport efficiency. Metabolic inhibitors applied during in vitro transepithelial transport experiments using the JAR cells significantly reduced the transport efficiency, indicating that active transport facilitated the transplacental transport of aryl-OPFRs, with reductions exceeding 50%. Molecular docking analysis indicated that aryl-OPFRs exhibited greater binding affinities to placental transporters compared to other types of OPFRs, with more bonding interactions. These findings offer new insights into the potential health impacts of OPFR exposure and highlight the importance of elucidating their transplacental transport mechanisms.

PBScreen: A server for the high-throughput screening of placental barrier-permeable contaminants based on multifusion deep learning

Contaminants capable of crossing the placental barrier (PB) adversely affect female reproduction and fetal development. The rapid identification of PB-permeable contaminants is urgently needed due to the inefficiencies of conventional cell-based transwell assays for the screening of large quantities of chemicals. Herein, we construct a PBScreen server using a multifusion deep learning (DL) model for the accurate and rapid screening of PB-permeable chemicals. This model is trained using graph convolutional networks and deep neural networks algorithms. It achieves state-of-the-art performance with an accuracy of 0.927, a false negative rate of 0.074, and an area under the receiver operating characteristic curve of 0.960. The robustness and generalization of the model as assessed using the external validation set and BeWo cell-based transwell assays demonstrate its potential for diverse applications. Our study establishes an efficient high-throughput screening tool that aids in screening PB-permeable chemicals, thereby enhancing the risk assessment of contaminants associated with key public health concerns.

Legacy and emerging organophosphate flame retardants (OPFRs) in water and sediment from the Pearl River Delta to the adjacent coastal waters of the South China Sea: Spatioseasonal variations, flux estimation and ecological risk

The industrialization and urbanization along the Pearl River Delta (PRD) have exacerbated the issue of pollution in aquatic environments by organophosphate flame retardants (OPFRs). Historical cumulative pollution from legacy OPFRs, combined with newly emerging OPFRs, has increased the severity and complexity of OPFR pollution in this region. We explored the contamination profile, input flux and risk of legacy and emerging OPFRs in surface waters and in sediment samples of the PRD. The results indicated that all OPFRs we targeted were detectable in the water samples; The sum concentration of OPFRs in the water ranged from 17.35 ng/L to 673.30 ng/L, with an average level of 215.11 ng/L; In sediments it ranged from 5.68 ng/g to 802.46 ng/g dry weight (dw). Tris(2-chloroisopropyl) phosphate (TCPP, 99.58 ng/L) and Bisphenol A diphenyl phosphate (BDP, 51.09 ng/g dw) were the most abundant OPFRs in the surface water and sediment, respectively. Notably, although Tetrekis (2-chlorethyl) dichloroisopentyl-diphosphate (V6) has only been used in recent years, its relatively high concentrations and proportions, both in water and sediment samples, demonstrate its now widespread occurrence in the PRD. The estimated annual flux of ΣOPFRs from the eight estuaries to the South China Sea was 45.04 t/y. The four estuaries (Humen, Modaomen, Hengmen and Honqimen) contribute 80% of the mass loading. Triphenyl phosphate (TPHP) and Tris (2-chloroethyl) phosphate (TCEP) in water posed relatively higher ecological risks to algae, daphnia, and fish than other OPFRs. Our results provide scientific support for continuing monitoring and control of OPFR pollution in the PRD.

A review on sustainable management strategies for navigating the piling e-waste crisis and associated environmental threats

In today's fast-paced technological era, multifaceted technological advancements in our contemporary lifestyle are surging the use of electronic devices, which are significantly piling e-waste and posing environmental concerns. This stock of e-waste is expected to keep rising up to 50 mt year-1. Formal recycling of such humongous waste is a major challenge, especially in developing nations. Mishandling of e-waste poses serious threats to human health, soil, and water ecosystem, threatening ecological and environmental sustainability. Complex matrix of resourceful materials comprising valuable metals like gold, silver, and copper, and hazardous substances such as lead, mercury, cadmium, and brominated flame retardants make its judicious management even more crucial. Potential toxic elements such as Pb, Cd, Cr, As, and Hg, as well as plastic/microplastics, nanoparticles are prevalent in components like batteries, cathode ray tubes, circuit boards, glass and plastic components which are known to cause neurological, renal, and developmental damage in humans. Effective and sustainable management of these requires a comprehensive understanding of their sources, environmental behavior, and toxicological impacts. This review explores potential approached for sustainable e-waste recycling (recycling of glass, plastic, rare earth metals, and base metals), and resource recycling through pyrometallurgy, hydrometallurgy, biometallurgy, biohydrometallurgy, bioleaching and biodegradation plastic alongside challenges and prospects.

New insights into the mechanism of triphenyl phosphate and its metabolite diphenyl phosphate in diabetic kidney disease

Diabetic kidney disease is a significant complication of diabetes mellitus, and exposure to certain chemicals may play a role in its development. Triphenyl phosphate (TPHP) is commonly used in plastics and flame retardants. This study aims to investigate the potential impact of TPHP and its metabolite diphenyl phosphate (DPHP) on diabetic kidney disease using various methods, including network toxicology, molecular docking, and cell experiments like CCK8 assay and real-time-PCR. The research examined the relationship between urinary DPHP levels and kidney function in American adults using data from the National Health and Nutrition Examination Survey (NHANES) from 2017 to March 2020. Additionally, the study explored the targets of action for TPHP and DPHP using network toxicity analysis, conducted protein interaction analysis, and explored the functional aspects of action through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis. Furthermore, the study identified key proteins involved in the action and conducted experimental verification by treating cells with TPHP and DPHP. Toxicity analysis showed that TPHP could cause dose-dependent toxicity in mouse podocyte clone 5 (MPC5) and mouse mesangial cells (MES13). The study also detected mRNA expression of core targets molecularly docked with TPHP and DPHP using real-time-PCR. The results indicated statistically significant regulation of most core targets by TPHP and DPHP in MPC5, MES13, and human kidney-2 cells.

Prenatal exposure to a mixture of organophosphate ester and organophosphorus pesticides in relation to child neurodevelopment in the Shanghai Birth Cohort

Neurotoxicity of organophosphate esters (OPEs) and organophosphorus pesticides (OPPs) has been documented in toxicological studies, though epidemiological evidence remains inconsistent. The developing fetal brain is susceptible to environmental exposures. Thus, we aim to investigate how prenatal exposure to OPEs and OPPs as mixture affects offspring neurodevelopment in preschool-aged children. In a study involving 530 mother-child dyads from the Shanghai Birth Cohort (SBC) with enrollment occurring between 2013 and 2016, 14 OPEs/OPPs metabolites were evaluated using high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS-MS) in maternal urine collected during both the first and second trimester. Child neurodevelopment was evaluated using the parent-reported Behavior Rating Inventory of Executive Function-Preschool version (BRIEF-P) and the Strengths and Difficulties Questionnaire (SDQ). We utilized multivariable linear regression and Bayesian kernel machine regression (BKMR) to estimate associations with individual and mixture component, respectively. We also investigated whether these associations varied by child sex. Of the 14 OPEs/OPPs metabolites, 6 were quantifiable in over 75 % of the samples. Higher prenatal O,O-dimethyl phosphate (DMP) concentrations in the first and second trimesters, as well as O,O-dimethyl thiophosphate (DMTP) in the second trimester, were associated with more behavioral difficulties. When stratified by child sex, the statistically significant inverse associations were observed exclusively in girls. Results from BKMR showed that the overall effect of prenatal exposure to OPEs and OPPs mixtures was associated with some neurodevelopmental domains in girls. For example, holding the mixture at the 75th percentile compared to the 50th percentile during the first trimester was associated with a 0.65 increase in SDQ total scores (95 % confidence interval: 0.03-1.26). DMP and DMTP may be the dominant contributors. Our findings add to the literature on the effect of prenatal exposure to OPEs and OPPs on offspring neurodevelopment and suggest that the effect seems to be sex-specific. Additional research is required to validate our findings and elucidate the underlying mechanisms.

Tris(2-chloroethyl) Phosphate Leads to Unbalanced Circulating Erythrocyte in Mice by Activating both Medullary and Extramedullary Erythropoiesis

Tris(2-chloroethyl) phosphate (TCEP), a prevalent organophosphorus flame retardant, has been identified in various environmental matrices and human blood samples, provoking alarm regarding its hematological toxicity, a subject that has not been thoroughly investigated. Red blood cells (RBCs), or erythrocytes, are the predominant cell type in peripheral blood and are crucial for the maintenance of physiological health. This investigation employed oral gavage to examine the effects of TCEP exposure on erythrocyte counts in mice and to clarify the underlying mechanisms. The results demonstrated a marked increase in circulating RBC counts post-TCEP exposure, concomitantly heightening the risk of polycythemia vera (PV). TCEP exposure stimulated erythropoiesis across all stages of medullary development, including the differentiation of hematopoietic stem cells into erythroid progenitors, the progression of erythrocyte development, and the maturation of erythrocyte. Moreover, TCEP potentiated extramedullary erythropoiesis in the spleen and liver. Subsequent bioinformatics analysis implied that TCEP-induced erythropoiesis was attributed to p53 downregulation. Thus, these findings indicate that TCEP disrupts erythrocyte-mediated hematological homeostasis through the enhancement of both medullary and extramedullary erythropoiesis, leading to the alteration of hematological equilibrium.

Prenatal Triphenyl Phosphate Exposure and Hyperlipidemia in Offspring: Role of Trophoblast-Derived Extracellular Vesicle PPARγ

Triphenyl phosphate (TPhP) is a widely used organophosphate flame retardant, the health risks of TPhP are a global concern. In this study, we found that prenatal TPhP exposure at human relevant concentration induced hyperlipidemia in male offspring, it increased serum levels of triglyceride, total cholesterol, and low-density lipoprotein cholesterol. Placental trophoblast-derived extracellular vesicles (T-EVs) could transport to the fetus through maternal-fetal circulation. TPhP significantly upregulated the protein level of peroxisome proliferator activated receptor γ (PPARγ) in T-EVs. Similar to TPhP, gestational exposure to T-EVs isolated from TPhP exposed mice placentae induced the same effects. While, gestational intervention with GW9662 (PPARγ inhibitor) or GW4869 (EVs secretion inhibitor) would alleviate the disturbed lipid metabolism induced by TPhP. Meanwhile, in vitro experiments verified that TPhP upregulated PPARγ in HTR8/SVneo cells derived EVs, and these EVs promoted adipogenesis in preadipocyte 3T3-L1 cells. Knock down of PPARγ in HTR8/SVneo could alleviate the adipogenensis effects of EVs derived from TPhP exposed HTR8/SVneo cells. These results demonstrate that TPhP exposure induces hyperlipidemia in male offspring by upregulating PPARγ in T-EVs. Our study provides new insights into the metabolic disruptive effects of TPhP, and emphasizes the mediating effects of placental T-EVs on gestational environmental stress in fetal development.

Gestational exposure to organophosphate esters and autism spectrum disorder and other non-typical development in a cohort with elevated familial likelihood

BACKGROUND

Gestational exposure to organophosphate esters (OPEs) is known to affect offspring neurodevelopment in animal studies. However, epidemiological evidence is inconsistent.

METHODS

Participants were 277 mother-child pairs from MARBLES (Markers of Autism Risk in Babies - Learning Early Signs), a cohort with elevated familial likelihood of autism spectrum disorder (ASD). Nine OPE biomarker concentrations were quantified in maternal urine collected during the 2nd or 3rd trimesters of pregnancy. At age 3 years, children underwent clinical assessment for ASD and were classified into ASD, other non-typical development (non-TD), or typical development (TD). Multinomial logistic regression was used to estimate associations between each OPE biomarker and relative risk ratios for ASD and non-TD compared to TD. We examined effect modification by child sex and socioeconomic status. We also conducted a secondary analysis by using a continuous measure of ASD symptom severity as an outcome. Quantile-based g-computation was performed to examine the associations for an OPE mixture.

RESULTS

Overall, no significant association was observed between the concentrations of each OPE biomarker or their mixture and relative risk for either ASD or non-TD. Effect modifications by child sex and maternal education were not observed. When the analysis was stratified by homeownership, among non-homeowners, ASD likelihood was increased with increased levels of bis(1-chloro-2-propyl) phosphate, bis(butoxyethyl) phosphate, and sum of di-n-butyl phosphate and di-iso-butyl phosphate (DBUP/DIBP) (pint < 0.10). Higher DBUP/DIBP were associated with increased ASD symptom severity scores.

CONCLUSION

There was no clear evidence of gestational OPE exposure in association with relative risk for ASD; however, potential effect modification by homeownership was observed. Although our cohort includes children with elevated familial likelihood of ASD, this is the first study investigating the association between gestational OPE exposure and clinically-diagnosed ASD. Further research is needed to confirm our findings in the general population.

Identification and seasonal variation of PM2.5-bound organophosphate flame retardants from industrial parks and the associated human health risk

Organophosphate flame retardants (OPFRs) have become pervasive environmental pollutants. However, there is a lack of information available regarding PM2.5-bound OPFRs emitted from industrial parks dedicated to the manufacturing and processing of metal-related products. In this study, 15 OPFRs in PM2.5 were identified from two industrial parks specializing in aluminum products and the deep processing of metals, respectively. The seasonal variations and health risks of OPFRs were investigated. The PM2.5 and OPFR concentrations were 26.0-203 μg/m3 and 12.4-6.38 × 104 pg/m3, respectively. The OPFRs concentrations in the aluminum-processing industrial park exceeded those found in the metal-fabrication industrial park. Among the chloro-, aryl-, and alkyl-substituted OPFRs (i.e., Cl-OPFRs, aryl-OPFRs, and alkyl-OPFRs), Cl-OPFRs were the predominant homologues in the two parks (69.3% and 51.4%) and the control site. Tetraethyl diphosphate and tris(2-chloroethyl) phosphate were the most commonly occurring homologues in the aluminum and metal-fabrication industrial parks, respectively. Seasonal variations of the target OPFRs were observed, although there were slightly different concentrations between the sites. The correlation and principal component analyses with multiple linear regression identified metal waste disposal as the leading source of OPFRs in metal parks (68.0%), followed by traffic emissions (25.3%), adhesives and flame retardants in construction-related substances (3.82%), and mechanical emissions (2.85%). The health risk assessment showed that the hazard quotients for non-carcinogenic risk were <1, and the carcinogenic risks were <10-6, which indicated that PM2.5-bound OPFRs presented no obvious non-carcinogenic or carcinogenic risks. Comparatively, the notably elevated noncarcinogenic and carcinogenic risks associated with Cl-OPFRs highlighted the importance of enforcing strict emission regulations during the disposal of metal waste.

Occupational exposure to traditional and emerging organophosphate esters: A comparison of levels across different sources and blood distribution

Currently, there is limited knowledge regarding occupational exposure of traditional and emerging organophosphate esters (OPEs) from e-waste and automobile dismantling activities, and their distribution within the human blood. In the present study, we collected dust and urine samples from e-waste (ED) (n = 91 and 130, respectively) and automobile dismantling (AD) plants (n = 93 and 94, respectively), as well as serum-plasma-whole blood samples (sets from 128 participants) within ED areas for analyzing traditional and emerging organophosphate tri-esters (tri-OPEs) and organophosphate di-esters (di-OPEs). Median concentration of ∑tri-OPEs and ∑di-OPEs in dust (37,400 and 9,000 ng/g in ED, and 27,000 and 14,700 ng/g in AD areas, respectively) and urine samples (11.8 and 21.9 ng/mL in ED areas, and 17.2 and 15.0 ng/mL in AD areas, respectively) indicated that both e-waste and automobile dismantling activities served as important pollution source for OPEs. Dust ingestion has been evidenced to be the main exposure pathway compared to dermal absorption and inhalation. The median concentration (ng/mL) of OPEs in blood matrices descended order as follow: whole blood (13.1) > serum (11.6) > plasma (10.4) for ∑tri-OPEs, and plasma (3.51) > serum (0.36) > whole blood (0.23) for ∑di-OPEs. Concentration ratios of OPEs varied across blood matrices, depending on the compounds, suggesting that the essentiality of appropriate biomonitoring matrix for conducting comprehensive exposure assessments.

Organophosphorus Flame Retardants and Metabolic Disruption: An in Silico, in Vitro, and in Vivo Study Focusing on Adiponectin Receptors

BACKGROUND

Environmental chemical exposures have been associated with metabolic outcomes, and typically, their binding to nuclear hormone receptors is considered the molecular initiating event (MIE) for a number of outcomes. However, more studies are needed to understand the influence of such exposures on cell membrane-bound adiponectin receptors (AdipoRs), which are critical metabolic regulators.

OBJECTIVE

We aimed to clarify the potential interactions between AdipoRs and environmental chemicals, specifically organophosphorus flame retardants (OPFRs), and the resultant effects.

METHODS

Employing in silico simulation, cell thermal shift, and noncompetitive binding assays, we screened eight OPFRs for interactions with AdipoR1 and AdipoR2. We tested two key events underlying AdipoR modulation upon OPFR exposure in a liver cell model. The Toxicological Prioritization Index (ToxPi)scoring scheme was used to rank OPFRs according to their potential to disrupt AdipoR-associated metabolism. We further examined the inhibitory effect of OPFRs on AdipoR signaling activation in mouse models.

RESULTS

Analyses identified pi-pi stacking and pi-sulfur interactions between the aryl-OPFRs 2-ethylhexyl diphenyl phosphate (EHDPP), triphenyl phosphate (TPhP), and tricresyl phosphate (TCP) and the transmembrane cavities of AdipoR1 and AdipoR2. Cell thermal shift assays showed a > 3 ° C rightward shift in the AdipoR proteins' melting curves upon exposure to these three compounds. Although the binding sites differed from adiponectin, results suggest that aryl-OPFRs noncompetitively inhibited the binding of the endogenous peptide ligand ADP355 to the receptors. Analyses of key events underlying AdipoR modulation revealed that glucose uptake was notably lower, whereas lipid content was higher in cells exposed to aryl-OPFRs. EHDPP, TCP, and TPhP were ranked as the top three disruptors according to the ToxPi scores. A noncompetitive binding between these aryl-OPFRs and AdipoRs was also observed in wild-type (WT) mice. In db/db mice, the finding of lower blood glucose levels after ADP355 injection was diminished in the presence of a typical aryl-OPFR (TCP). WT mice exposed to TCP demonstrated lower AdipoR1 signaling, which was marked by lower phosphorylated AMP-activated protein kinase (pAMPK) and a higher expression of gluconeogenesis-related genes. Moreover, WT mice exposed to ADP355 demonstrated higher levels of pAMPK protein and peroxisome proliferator-activated receptor-α messenger RNA. This was accompanied by higher glucose disposal and by lower levels of long-chain fatty acids and hepatic triglycerides; these metabolic improvements were negated upon TCP co-treatment.

CONCLUSIONS

In silico, in vitro, and in vivo assays suggest that aryl-OPFRs act as noncompetitive inhibitors of AdipoRs, preventing their activation by adiponectin, and thus function as antagonists to these receptors. Our study describes a novel MIE for chemical-induced metabolic disturbances and highlights a new pathway for environmental impact on metabolic health. https://doi.org/10.1289/EHP14634.

Partitioning of an Enzyme-Polymer Surfactant Nanocomplex into Lipid-Rich Cellular Compartments Drives In Situ Hydrolysis of Organophosphates

Most organophosphates (OPs) are hydrophobic, and after exposure, can sequester into lipophilic regions within the body, such as adipose tissue, resulting in long term chronic effects. Consequently, there is an urgent need for therapeutic agents that can decontaminate OPs in these hydrophobic regions. Accordingly, an enzyme-polymer surfactant nanocomplex is designed and tested comprising chemically supercharged phosphotriesterase (Agrobacterium radiobacter; arPTE) electrostatically conjugated to amphiphilic polymer surfactant chains ([cat.arPTE][S-]). Experimentally-derived structural data are combined with molecular dynamics (MD) simulations to provide atomic level detail on conformational ensembles of the nanocomplex using dielectric constants relevant to aqueous and lipidic microenvironments. These show the formation of a compact admicelle pseudophase surfactant corona under aqueous conditions, which reconfigures to yield an extended conformation at a low dielectric constant, providing insight into the mechanism underpinning cell membrane binding. Significantly, it demonstrated that [cat.arPTE][S-] spontaneously binds to human mesenchymal stem cell membranes (hMSCs), resulting in on-cell OP hydrolysis. Moreover, the nanoconstruct can endocytose and partition into the intracellular fatty vacuoles of adipocytes and hydrolyze sequestered OP.

Analysis of the evolution of placental oxidative stress research from a bibliometric perspective

Background

Research on placental oxidative stress is pivotal for comprehending pregnancy-related physiological changes and disease mechanisms. Despite recent advancements, a comprehensive review of current status, hotspots, and trends remains challenging. This bibliometric study systematically analyzes the evolution of placental oxidative stress research, offering a reference for future studies.

Objective

To conduct a comprehensive bibliometric analysis of the literature on placental oxidative stress to identify research hotspots, trends, and key contributors, thereby providing guidance for future research.

Methods

Relevant data were retrieved from the Web of Science Core Collection database and analyzed using VOSviewer, CiteSpace, and the bibliometrix package. An in-depth analysis of 4,796 publications was conducted, focusing on publication year, country/region, institution, author, journal, references, and keywords. Data collection concluded on 29 April 2024.

Results

A total of 4,796 papers were retrieved from 1,173 journals, authored by 18,835 researchers from 4,257 institutions across 103 countries/regions. From 1991 to 2023, annual publications on placental oxidative stress increased from 7 to 359. The United States (1,222 publications, 64,158 citations), the University of Cambridge (125 publications, 13,562 citations), and Graham J. Burton (73 publications, 11,182 citations) were the most productive country, institution, and author, respectively. The journal Placenta had the highest number of publications (329) and citations (17,152), followed by the International Journal of Molecular Sciences (122 publications). The most frequent keywords were "oxidative stress," "expression," "pregnancy," "preeclampsia," and "lipid peroxidation." Emerging high-frequency keywords included "gestational diabetes mellitus," "health," "autophagy," "pathophysiology," "infection," "preterm birth," "stem cell," and "inflammation."

Conclusion

Over the past 3 decades, research has concentrated on oxidative stress processes, antioxidant mechanisms, pregnancy-related diseases, and gene expression regulation. Current research frontiers involve exploring pathophysiology and mechanisms, assessing emerging risk factors and environmental impacts, advancing cell biology and stem cell research, and understanding the complex interactions of inflammation and immune regulation. These studies elucidate the mechanisms of placental oxidative stress, offering essential scientific evidence for future intervention strategies, therapeutic approaches, and public health policies.

Identification of Primary Organophosphate Esters Contributing to Enhanced Risk of Gestational Diabetes Mellitus Based on a Case-Control Study

Epidemiological studies on associations of organophosphate ester (OPE) exposure and gestational diabetes mellitus (GDM) risk, which remain rare and inconclusive, were carried out with a case-control population comprising 287 GDM and 313 non-GDM pregnant women recruited from Tianjin. The GDM group suffered distinctly higher serum concentrations of tri-n-butyl phosphate (TNBP), tri(2-butoxyethyl) phosphate (TBOEP), triphenyl phosphate (TPHP), tri-iso-propyl phosphate (TIPP), and tri(1-chloro-2-propyl) phosphate (TCIPP) than the healthy control group (p < 0.001). Traditional analysis methods employed for either individual or mixture effects found positive correlations (p < 0.05) between the concentrations of five OPEs (i.e., TNBP, TBOEP, TPHP, TIPP, and TCIPP) and the incidence of GDM, while 2-ethylhexyl diphenyl phosphate, tri(1-chloro-2-propyl) phosphate, and bis(2-ethylhexyl) phosphate exhibited opposite effects. Three machine learning methods considering the concurrence of OPE mixture exposure and population characteristics were applied to clarify their relative importance to GDM risk, among which random forest performed the best. Several OPEs, particularly TNBP and TBOEP ranking at the top, made greater contributions than some demographical characteristics, such as prepregnancy body mass index and family history of diabetes, to the occurrence of GDM. This was further validated by another independent case-control population obtained from Hangzhou.

Prenatal triphenyl phosphate exposure impairs placentation and induces preeclampsia-like symptoms in mice

Triphenyl phosphate (TPhP) is an organophosphate flame retardant that is widely used in many commercial products. The United States Environmental Protection Agency has listed TPhP as a priority compound that requires health risk assessment. We previously found that TPhP could accumulate in the placentae of mice and impair birth outcomes by activating peroxisome proliferator-activated receptor gamma (PPARγ) in the placental trophoblast. However, the underlying mechanism remains unknown. In this study, we used a mouse intrauterine exposure model and found that TPhP induced preeclampsia (PE)-like symptoms, including new on-set gestational hypertension and proteinuria. Immunofluorescence analysis showed that during placentation, PPARγ was mainly expressed in the labyrinth layer and decidua of the placenta. TPhP significantly decreased placental implantation depth and impeded uterine spiral artery remodeling by activating PPARγ. The results of the in vitro experiments confirmed that TPhP inhibited extravillous trophoblast (EVT) cell migration and invasion by activating PPARγ and inhibiting the PI3K-AKT signaling pathway. Overall, our data demonstrated that TPhP could activate PPARγ in EVT cells, inhibit cell migration and invasion, impede placental implantation and uterine spiral artery remodeling, then induce PE-like symptom and impair birth outcomes. Although the exposure doses used in this study was several orders of magnitude higher than human daily intake, our study highlights the placenta as a potential target organ of TPhP worthy of further research.

Emerging N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and 6PPD quinone in paired human plasma and urine from Tianjin, China: Preliminary assessment with demographic factors

With increasing concerns about N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and 6PPD-quinone (6PPD-Q), relevant environmental investigations and toxicological research have sprung up in recent years. However, limited information could be found for human body burden assessment. This work collected and analyzed 200 samples consisting of paired urine and plasma samples from participants (50 male and 50 female) in Tianjin, China. Low detection frequencies (DF, <15 %) were found except for urinary 6PPD-Q (86 %), which suggested the poor residue tendency of 6PPD and 6PPD-Q in blood. The low DFs also lead to no substantial association between two chemicals. Data analysis based on urinary 6PPD-Q showed a significant difference between males and females (p < 0.05). No significant correlation was found for other demographic factors (Body Mass Index (BMI), age, drinking, and smoking). The mean values of daily excretion (ng/kg bw/day) calculated using urinary 6PPD-Q for females and males were 7.381 ng/kg bw/day (female) and 3.360 ng/kg bw/day (male), and apparently female suffered higher daily exposure. Further analysis with daily excretion and ALT (alanine aminotransferase)/TSH (thyroid stimulating hormone)/ blood cell analysis indicators found a potential correlation with 6PPD-Q daily excretion and liver/immune functions. Considering this preliminary assessment, systematic research targeting the potential organs at relevant concentrations is required.

Biotransformation, Bioaccumulation, and Bioelimination of Triphenyl Phosphate and Its Dominant Metabolite Diphenyl Phosphate In Vivo

Aryl phosphorus flame retardants (aryl-PFRs), such as triphenyl phosphate (TPHP) and diphenyl phosphate (DPHP), are widely used worldwide. Understanding the fates of aryl-PFRs in vivo is crucial to assessing their toxicity and the risks they pose. Seven TPHP metabolites, including Phase I hydrolysis and hydroxylation and Phase II glucuronidation products, were identified in C57BL/6J male mice following subacute dietary exposure to aryl-PFRs (70 μg/kg body weight (bw)/day) for 7 days. TPHP was almost completely metabolized by mice (∼97%), with DPHP the major metabolite formed (34%-58%). In addition, mice were exposed to aryl-PFRs (7 μg/kg bw/day) for 12 weeks. Both TPHP and DPHP occurred at higher concentrations in the digestive tract (intestine and stomach), liver and heart. The total concentration of DPHP in all organs was 3.55-fold greater than that of TPHP. Recovery analysis showed that the rate of TPHP elimination from mouse organs reached 38%, while only 3%-5% of DPHP was removed, suggesting that the rates of degradation and elimination of DPHP were slower than TPHP and its bioaccumulation potential was higher. These results highlight the critical role of DPHP in the biotransformation, bioaccumulation, and bioelimination of TPHP, providing valuable insights into the fate of aryl-PFRs in vivo.

Embryonic Exposure to Organophosphate Flame Retardants (OPFRs) Differentially Induces Cardiotoxicity in Rare Minnow (Gobiocypris rarus)

Organophosphorus flame retardants (OPFRs) such as triphenyl phosphate (TPHP) and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) were reported to impair cardiac function in fish. However, limited information is available regarding their cardiotoxic mechanisms. Using rare minnow (Gobiocypris rarus) as a model, we found that both TPHP and TDCIPP exposures decreased heart rate at 96 h postfertilization (hpf) in embryos. Atropine (an mAChR antagonist) can significantly attenuate the bradycardia caused by TPHP, but only marginally attenuated in TDCIPP treatment, suggesting that TDCIPP-induced bradycardia is independent of mAChR. Unlike TDCIPP, although TPHP-induced bradycardia could be reversed by transferring larvae to a clean medium, the inhibitory effect of AChE activity persisted compared to 96 hpf, indicating the existence of other bradycardia regulatory mechanisms. Transcriptome profiling revealed cardiotoxicity-related pathways in treatments at 24 and 72 hpf in embryos/larvae. Similar transcriptional alterations were also confirmed in the hearts of adult fish. Further studies verified that TPHP and TDCIPP can interfere with Na+/Ca2+ transport and lead to disorders of cardiac excitation-contraction coupling in larvae. Our findings provide useful clues for unveiling the differential cardiotoxic mechanisms of OPFRs and identifying abnormal Na+/Ca2+ transport as one of a select few known factors sufficient to impair fish cardiac function.

Association of co-exposure to organophosphate esters and per- and polyfluoroalkyl substances and mixture with cardiovascular-kidney-liver-metabolic biomarkers among Chinese adults

BACKGROUND

Organophosphate esters (OPEs) and Per- and polyfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants with common exposure sources, leading to their widespread presence in human body. However, evidence on co-exposure to OPEs and PFAS and its impact on cardiovascular-kidney-liver-metabolic biomarkers remains limited.

METHODS

In this cross-sectional study, 467 adults were enrolled from January to May 2022 during physical visits in Shijiazhuang, Hebei province. Eleven types of OPEs and twelves types of PFAS were detected, among which eight OPEs and six PFAS contaminants were detected in more than 60% of plasma samples. Seventeen biomarkers were assessed to comprehensively evaluate the cardiovascular-kidney-liver-metabolic function. Multiple linear regression, multipollutant models with sparse partial least squares, and Bayesian kernel machine regression (BKMR) models were applied to examine the associations of individual OPEs and PFAS and their mixtures with organ function and metabolism, respectively.

RESULTS

Of the over 400 exposure-outcome associations tested when modelling, we observed robust results across three models that perfluorohexanoic acid (PFHxS) was significantly positively associated with alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), and indirect bilirubin (IBIL). Perfluorononanoic acid was significantly associated with decreased AST/ALT and increased very-low-density lipoprotein cholesterol levels. Besides, perfluorodecanoic acid was correlated with increased high lipoprotein cholesterol and perfluoroundecanoic acid was consistently associated with lower glucose level. BKMR analysis showed that OPEs and PFAS mixtures were positively associated with IBIL and TBIL, among which PFHxS was the main toxic chemicals.

CONCLUSIONS

Our findings suggest that exposure to OPEs and PFAS, especially PFHxS and PFNA, may disrupt organ function and metabolism in the general population, providing insight into the potential pathophysiological mechanisms of OPEs and PFAS co-exposure and chronic diseases.

Potential Adverse Outcome Pathways of Chlorinated Organophosphate Flame Retardants

What is already known about this topic?

Chlorinated organophosphate flame retardants (Cl-OPFRs) are frequently detected chemicals in the environment and biological samples, yet there is a lack of systematic evaluation regarding the adverse effects and toxicological mechanisms of Cl-OPFRs.

What is added by this report?

This study utilizes the adverse outcome pathway (AOP) framework to assess the health implications and mechanisms of Cl-OPFRs, identifying multi-system toxicity, with a particular emphasis on reproductive issues and the possible toxic mechanisms.

What are the implications for public health practice?

These results enhance knowledge of the health hazards linked to Cl-OPFRs, supporting the creation of focused risk evaluations and suitable regulatory actions.

Microplastics in maternal amniotic fluid and their associations with gestational age

Microplastics (MPs) pollution is a growing global concern due to its potential threat to human health, particularly concerning fetal health. Nevertheless, few studies have examined the sources of fetal MPs exposure and its impact on fetal development. In this study, MPs levels in maternal amniotic fluid (AF) and their associations with measures of fetal growth were investigated. Specifically, 40 human AF samples were collected to determine the presence and characteristics of MPs using laser direct infrared (LD-IR) spectroscopy. MPs were found in 32 out of 40 AF samples, with an average abundance of 2.01 ± 4.19 particles/g. Polyethylene (PE, 38.80 %) and chlorinated polyethylene (CPE, 26.98 %) were the most prevalent polymers. The majority of MPs (87.56 %) were 20-100 μm in size, and fragments (71.23 %) evidently prevailed in morphology. Additionally, a questionnaire was designed to explore the associations between MPs levels in the AF and maternal dietary habits, aiming at unveiling the potential sources of MPs in AF. The MPs levels in the AF were positively associated with the frequency of seafood consumption (r = 0.781, P < 0.001) and bottled water intake (r = 0.386, P = 0.014). Moreover, the associations between MPs levels in maternal AF and measures of fetal growth were evaluated. The abundance of total MPs in maternal AF were significantly negatively associated with gestational age (β = -0.44, 95 % CI, -0.83, -0.05). This study confirms the presence of MPs in human AF and provides compelling evidence linking them to gestational age, while highlighting the potential risks associated with dietary habits. These findings underscore the need for further investigation into the mechanisms of MPs transmission from mother to fetus and the potential health implications during fetal development, offering valuable insights for future policies aimed at safeguarding maternal and fetal health.

First Insight into Fetal Exposure to Legacy and Emerging Plasticizers Revealed by Infant Hair and Meconium: Occurrence, Biotransformation, and Accumulation

Epidemiological studies have demonstrated the embryonic and developmental toxicity of plasticizers. Thus, understanding the in utero biotransformation and accumulation of plasticizers is essential to assessing their fate and potential toxicity in early life. In the present study, 311 infant hair samples and 271 paired meconium samples were collected at birth in Guangzhou, China, to characterize fetal exposure to legacy and emerging plasticizers and their metabolites. Results showed that most of the target plasticizers were detected in infant hair, with medians of 9.30, 27.6, and 0.145 ng/g for phthalate esters (PAEs), organic phosphate ester (OPEs), and alternative plasticizers (APs), and 1.44, 0.313, and 0.066 ng/g for the metabolites of PAEs, OPEs, and APs, respectively. Positive correlations between plasticizers and their corresponding primary metabolites, as well as correlations among the oxidative metabolites of bis(2-ethylhexyl) phthalate (DEHP) and 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH), were observed, indicating that infant hair retained the major phase-I metabolism of the target plasticizers. While no positive correlations were found in parent compounds or their primary metabolites between paired infant hair and meconium, significant positive correlations were observed among secondary oxidative metabolites of DEHP and DINCH in hair and meconium, suggesting that the primary metabolites in meconium come from hydrolysis of plasticizers in the fetus but most of the oxidative metabolites come from maternal-fetal transmission. The parent compound/metabolite ratios in infant hair showed a decreasing trend across pregnancy, suggesting in utero accumulation and deposition of plasticizers. To the best of our knowledge, this study is the first to report in utero exposure to both parent compounds and metabolites of plasticizers by using paired infant hair and meconium as noninvasive biomonitoring matrices and provides novel insights into the fetal biotransformation and accumulation of plasticizers across pregnancy.

Effects of uptake pathways on the accumulation, translocation, and metabolism of OPEs in rice: An emphasis on foliar uptake

The often-overlooked importance of foliar absorption on the plant uptake of organic pollutants was investigated by an exposure chamber test. Rice seedlings were exposed to organophosphate esters (OPEs) through 8 scenarios arranged from 3 major uptake pathways: root uptake via solution, foliar uptake via gas, and foliar uptake via particles, to identify the contributions of these 3 uptake pathways and their influences on the translocation and metabolism of OPEs in rice. The concentration of OPEs in rice tissues showed an "additive effect" with the increase of exposure pathways. OPEs in rice shoots mainly originated from foliar uptake through particle (29.6 %-63.5 %) and gaseous (28.5 %-49.4 %) absorptions rather than root uptake (7.86 %-24.2 %) under the exposure condition. In comparison with stomal absorption, wax layer penetration was the main pathway for most OPEs to enter into leaves, especially for those compounds with high octanol-air partition coefficients. Although the subcellular distributions of OPEs in the rice tissues of the foliar exposure were slightly different from those of the root exposure, hydrophobic OPEs were mainly stored in the cell wall with hydrophilic OPEs mainly in the cytosol. The translocation of OPEs from the exposed tissue to the unexposed tissue were significantly negatively correlated with their octanol-water partition coefficients, but their basipetal translocation were limited. The result suggested that the translocation of OPEs within rice is prioritized over their degradation. This study deepens our understanding of the processes behind OPE uptake by rice and highlights the importance of foliar uptake, especially for those via particle absorption.

Multigenerational effects and mutagenicity of three flame retardants on germ cells in Caenorhabditis elegans

Flame retardants (FRs) have raised public concerns because of their environmental persistence and negative impacts on human health. Recent evidence has revealed that many FRs exhibit reproductive toxicities and transgenerational impacts, whereas the toxic effects of FRs on germ cells remain barely explored. Here we investigated the multigenerational effects of three flame retardants (TBBPA, TCEP and TCPP) on germ cell development in Caenorhabditis elegans, and examined the germ cell mutagenicity of these FRs by using whole genome sequencing. Parental exposure to three FRs markedly increased germ cell apoptosis, and impeded oogenesis in F1-F6 offspring. In addition, the double-increased mutation frequencies observed in progeny genomes uncover the mutagenic actions of FRs on germ cells. Analysis of mutation spectra revealed that these FRs predominantly induced point mutations at A:T base pairs, whereas both small and large indels were almost unaffected. These results revealed the long-term effects of FRs on development and genomic stability of germ cells, which may pose risks to environmental organisms and human reproductive health. Taken together, our findings suggest that germ cell mutagenicity should be carefully examined for the environmental risk assessment of FRs and other emerging pollutants.

Synthetic Antioxidants as Contaminants of Emerging Concern in Indoor Environments: Knowns and Unknowns

Synthetic antioxidants, including synthetic phenolic antioxidants (SPAs), amine antioxidants (AAs), and organophosphite antioxidants (OPAs), are essential additives for preventing oxidative aging in various industrial and consumer products. Increasing attention has been paid to the environmental contamination caused by these chemicals, but our understanding of synthetic antioxidants is generally limited compared to other emerging contaminants such as plasticizers and flame retardants. Many people spend a significant portion (normally greater than 80%) of their time indoors, meaning that they experience widespread and persistent exposure to indoor contaminants. Thus, this Perspective focuses on the problem of synthetic antioxidants as indoor environmental contaminants. The wide application of antioxidants in commercial products and their demonstrated toxicity make them an important family of indoor contaminants of emerging concern. However, significant knowledge gaps still need to be bridged: novel synthetic antioxidants and their related transformation products need to be identified in indoor environments, different dust sampling strategies should be employed to evaluate human exposure to these contaminants, geographic scope and sampling scope of research on indoor contamination should be broadened, and the partition coefficients of synthetic antioxidants among different media need to be investigated.

Toxicity assessment of organophosphate flame retardant triphenyl phosphate (TPHP) on intestines in mice

Triphenyl phosphate (TPHP), one widely used organophosphate flame retardant, has attracted accumulating attention due to its high detection rate in human biological samples. Up to date, the effects of TPHP exposure on intestinal health remain unexplored. In this study, BALB/c mice were used as a model and exposed to TPHP at dose of 2, 10, or 50 mg/kg body weight for 28 days. We observed Crohn's disease-like features in ileum and ulcerative colitis disease-like features in colon, such as shorter colon length, ileum/colon structure impairment, intestinal epithelial cell apoptosis, enrichment of proinflammatory cytokines and immune cells, and disruption of tight junction. Furthermore, we found that TPHP induced production of reactive oxygen species and apoptosis in intestinal epithelial Caco-2 cells, accompanied by disruption of tight junction between cells. To understand the molecular mechanism underlying TPHP-induced changes in intestines, we build the adverse outcome pathway (AOP) framework based on Comparative Toxicogenomics and GeneCards database. The AOP framework revealed that PI3K/AKT and FoxO signaling pathway might be associated with cellular apoptosis, an increase in ROS production, and increased inflammation response in mouse ileum and colon tissues challenged with TPHP. These results identified that TPHP induced IBD-like features and provided new perspectives for toxicity evaluation of TPHP.