Prenatal exposure to organic pollutants in northwestern Spain using non-invasive matrices (placenta and meconium)

Fetus Exposure to Drugs and Chemicals: A Holistic Overview on the Assessment of Their Transport and Metabolism across the Human Placental Barrier

BACKGROUND

The placenta exerts a crucial role in fetus growth and development during gestation, protecting the fetus from maternal drugs and chemical exposure. However, diverse drugs and chemicals (xenobiotics) can penetrate the maternal placental barrier, leading to deleterious, adverse effects concerning fetus health. Moreover, placental enzymes can metabolize drugs and chemicals into more toxic compounds for the fetus. Thus, evaluating the molecular mechanisms through which drugs and chemicals transfer and undergo metabolism across the placental barrier is of vital importance. In this aspect, this comprehensive literature review aims to provide a holistic approach by critically summarizing and scrutinizing the potential molecular processes and mechanisms governing drugs and chemical transfer and metabolism across the placental barrier, which may lead to fetotoxicity effects, as well as analyzing the currently available experimental methodologies used to assess xenobiotics placental transfer and metabolism.

METHODS

A comprehensive and in-depth literature review was conducted in the most accurate scientific databases such as PubMed, Scopus, and Web of Science by using relevant and effective keywords related to xenobiotic placental transfer and metabolism, retrieving 8830 published articles until 5 February 2024. After applying several strict exclusion and inclusion criteria, a final number of 148 relevant published articles were included.

RESULTS

During pregnancy, several drugs and chemicals can be transferred from the mother to the fetus across the placental barrier by either passive diffusion or through placental transporters, resulting in fetus exposure and potential fetotoxicity effects. Some drugs and chemicals also appear to be metabolized across the placental barrier, leading to more toxic products for both the mother and the fetus. At present, there is increasing research development of diverse experimental methodologies to determine the potential molecular processes and mechanisms of drug and chemical placental transfer and metabolism. All the currently available methodologies have specific strengths and limitations, highlighting the strong demand to utilize an efficient combination of them to obtain reliable evidence concerning drug and chemical transfer and metabolism across the placental barrier. To derive the most consistent and safe evidence, in vitro studies, ex vivo perfusion methods, and in vivo animal and human studies can be applied together with the final aim to minimize potential fetotoxicity effects.

CONCLUSIONS

Research is being increasingly carried out to obtain an accurate and safe evaluation of drug and chemical transport and metabolism across the placental barrier, applying a combination of advanced techniques to avoid potential fetotoxic effects. The improvement of the currently available techniques and the development of novel experimental protocols and methodologies are of major importance to protect both the mother and the fetus from xenobiotic exposure, as well as to minimize potential fetotoxicity effects.

Effects of DDT and DDE on placental cholinergic receptors

The placental cholinergic system; known as an important factor in intracellular metabolic activities, regulation of placental vascular tone, placental development, and neurotransmission; can be affected by persistent organic pesticides, particularly organochlorine pesticides(OCPs), which can influence various epigenetic regulations and molecular pathways. Although OCPs are legally prohibited, trace amounts of the persistent dichlorodiphenyltrichloroethane(DDT) are still found in the environment, making prenatal exposure inevitable. In this study, the effects of 2,4'-DDT and 4,4'-DDT; and its breakdown product 4,4'-DDE in the environment on placental cholinergic system were evaluated with regards to cholinergic genes. 40 human placentas were screened, where 42,50% (17 samples) were found to be positive for the tested compounds. Average concentrations were 10.44 μg/kg; 15.07 μg/kg and 189,42 μg/kg for 4,4'-DDE; 2,4'-DDT and 4,4'-DDT respectively. RNA-Seq results revealed 2396 differentially expressed genes in positive samples; while an increase in CHRM1,CHRNA1,CHRNG and CHRNA2 genes at 1.28, 1.49, 1.59 and 0.4 fold change were found(p<0028). The increase for CHRM1 was also confirmed in tissue samples with immunohistochemistry. In vitro assays using HTR8/SVneo cells; revealed an increase in mRNA expression of CHRM1, CHRM3 and CHRN1 in DDT and DDE treated groups; which was also confirmed through western blot assays. An increase in the expression of CHRM1,CHRNA1, CHRNG(p<0001) and CHRNA2(p<0,05) were found from the OCPs exposed and non exposed groups.The present study reveals that intrauterine exposure to DDT affects the placental cholinergic system mainly through increased expression of muscarinic receptors. This increase in receptor expression is expected to enhance the sensitivity of the placental cholinergic system to acetylcholine.

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.

Meconium Concentrations of Pesticides and Risk of Hypospadias: A Case-Control Study in Brittany, France

BACKGROUND

Hypospadias is a male genital tract defect for which an increase in prevalence has been documented over the last few decades. A role for environmental risk factors is suspected, including prenatal exposure to pesticides.

OBJECTIVES

To study the risk of hypospadias in association with multiple pesticide measurements in meconium samples.

METHODS

The Brittany Registry of Congenital Anomalies (France) conducted a case-control study between 2012 and 2018. Cases were hypospadias, ascertained by a pediatrician and a pediatric surgeon, excluding genetic conditions, following European Surveillance of Congenital Anomalies guidelines (N = 69). Controls (N = 135) were two male infants without congenital anomaly born after each case in the same maternity unit. Mothers in the maternity units completed a self-administered questionnaire, we collected medical data from hospital records, and medical staff collected meconium samples. We performed chemical analysis of 38 pesticides (parent compound and/or metabolite) by UHPLC/MS/MS following strict quality assurance/quality control criteria and blind to case-control status. We carried out logistic regression accounting for frequency-matching variables and major risk factors.

RESULTS

Among the 38 pesticides measured, 16 (42%) were never detected in the meconium samples, 18 (47%) were in <5% of samples, and 4 (11%) in ≥5% of the samples. We observed an association between the detection of fenitrothion in meconium and the risk of hypospadias (OR = 2.6 [1.0-6.3] with n cases = 13, n controls = 21), but not the other pesticides.

CONCLUSIONS

Our small study provides a robust assessment of fetal exposure. Fenitrothion's established antiandrogenic activities provide biologic plausibility for our observations. Further studies are needed to confirm this hypothesis.

Multiclass Determination of Endocrine-Disrupting Chemicals in Meconium: First Evidence of Perfluoroalkyl Substances in This Biological Compartment

Major concerns have been raised about human exposure to endocrine-disrupting chemicals (EDCs) during pregnancy. Effective methodologies for the assessment of this exposure are needed to support the implementation of preventive measures and the prediction of negative health effects. Meconium has proven a valuable non-invasive matrix for evaluating cumulative exposure to xenobiotics during the last two trimesters of pregnancy. The study objective was to develop a novel method to determine the presence in meconium of perfluoroalkyl substances (PFASs), bisphenols, parabens, and benzophenones, EDCs that are widely used in the manufacture of numerous consumer goods and personal care products, including cosmetics. Ten PFASs, two bisphenols, four parabens, and four benzophenones were measured in meconium samples prepared by using a combination of Captiva Enhanced Matrix Removal (EMR) lipid cartridges with salt-assisted liquid-liquid extraction (SALLE) and dispersive liquid-liquid microextraction (DLLME) before the application of liquid chromatography-tandem mass spectrometry (LC-MS/MS). Experimental parameters were optimized by applying different chemometric techniques. Limits of detection ranged from 0.05 to 0.1 ng g-1, and between-day variabilities (relative standard deviations) ranged from 6.5% to 14.5%. The method was validated by matrix-matched standard calibration followed by a recovery assay with spiked samples, obtaining percentage recoveries of 89.9% to 114.8%. The method was then employed to measure compounds not previously studied in this matrix in 20 meconium samples. The proposed analytical procedure yields information on cumulative in utero exposure to selected EDCs.

Exposure levels and determinants of placental polybrominated diphenyl ethers in Chinese pregnant women

BACKGROUND

Polybrominated diphenyl ethers (PBDEs) are a group of widely used chemicals and humans are exposed to them in their daily life. PBDEs exposure during pregnancy may have adverse effects on pregnant women and their fetuses. Nevertheless, limited information is available on the levels and determinants of PBDEs exposure in Chinese pregnant women.

METHODS

The internal exposure levels of eight PBDEs (BDE-28, 47, 99, 100, 153, 154, 183, and 209) in placental samples of 1280 pregnant women from Zunyi birth cohort were analyzed using gas chromatography tandem mass spectrometry. All PBDEs concentrations were lipid adjusted (ng/g lw). Determinants of exposure were assessed by multivariable logistic regression model.

RESULTS

Eight PBDE homologues were quantifiable in more than 70% of the samples. The highest median concentrations were found for BDE-209 (2.78 ng/g lw), followed by BDE-153 (1.00 ng/g lw) and BDE-183 (0.93 ng/g lw). The level of ΣPBDEs ranged from 0.90 to 308.78 ng/g lw, with a median concentration of 10.02 ng/g lw. Multivariate logistic regression analysis showed that maternal age older than 30 years old (OR: 1.59; 95% CI: 1.14, 2.23), pre-pregnancy obesity (1.51; 1.08, 2.10), home renovation within 2 years (1.43; 1.08, 1.91), spending more time outdoors during pregnancy (0.70; 0.55, 0.89), high consumption of fish/seafood (1.46; 1.13, 1.90) and eggs (1.44; 1.04, 2.00), male infant sex (1.69; 1.18, 2.42) were associated with PBDEs exposure.

CONCLUSION

The study population is generally exposed to PBDEs, of which BDE-209 is the dominant congener, indicating extensive application of products containing deca-BDE mixtures. Maternal age, pre-pregnancy BMI, home decoration, average outdoor time during pregnancy, fish, seafood, eggs consumption, and fetal sex were exposure-determinning factors. This study contributes to the knowledge on region-specific PBDEs contamination in pregnant women and related risk factors.

Placental concentrations of xenoestrogenic organochlorine pesticides and polychlorinated biphenyls and assessment of their xenoestrogenicity in the PA-MAMI mother-child cohort

BACKGROUND

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCB), they have contributed to the exposure of women to persistent organic pollutants (POPs). These compounds can cross the placental barrier and interfere with the hormonal system of newborns.

AIM

To determine concentrations of OCPs and PCBs and their xenoestrogenic activity in placentas of women from the PA-MAMI cohort of Panama.

METHODS

Thirty-nine placenta samples from women in the Azuero peninsula (Panama) were analyzed. Five OCPs [p-p'-dichlorodiphenyldichloroethylene (p-p'-DDE), beta-hexachlorohexane (β-HCH), γ-hexachlorohexane (lindane), hexachlorobenzene (HCB) and mirex] and three PCB congeners (PCB-138, PCB-153 and PCB-180) were quantified in placenta extracts. The xenoestrogenic activity of extracts was assessed with the E-Screen bioassay to estimate the total effective xenoestrogen burden (TEXB).

RESULTS

All placental samples were positive for at least three POP residues and >70% for at least six. The frequencies of quantified OCPs ranged from 100% for p,p'-DDE and HCB to 30.8% for β-HCH. The highest median concentration was for lindane (380.0 pg/g placenta), followed by p,p'-DDE (280.0 pg/g placenta), and HCB (90.0 pg/g placenta). Exposure to p,p'-DDE was associated with greater meat consumption, suggesting that animal fat is a major source of exposure to DDT metabolites. The frequency of detected PCBs ranged between 70 and 90%; the highest median concentration was for PCB 138 (17.0 pg/g placenta), followed by PCB 153 (16.0 pg/g placenta). All placentas were positive in the estrogenicity bioassay with a median TEXB-α of 0.91 pM Eeq/g of placenta. Exposure to lindane was positively associated with the xenoestrogenicity of TEXB- α, whereas this association was negative in the case of exposure to PCB 153.

CONCLUSIONS

To our best knowledge, this study contributes the first evidence on the presence of POPs and xenoestrogenic burden in placentas from Latin-American women. Given concerns about the consequences of prenatal exposure to these compounds on children's health, preventive measures are highly recommended to eliminate or minimize the risk of OCP exposure during pregnancy.

Update of the risk assessment of polybrominated diphenyl ethers (PBDEs) in food

The European Commission asked EFSA to update its 2011 risk assessment on polybrominated diphenyl ethers (PBDEs) in food, focusing on 10 congeners: BDE-28, -47, -49, -99, -100, -138, -153, -154, -183 and ‑209. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour and reproductive/developmental effects are the critical effects in rodent studies. For four congeners (BDE-47, -99, -153, -209) the Panel derived Reference Points, i.e. benchmark doses and corresponding lower 95% confidence limits (BMDLs), for endpoint-specific benchmark responses. Since repeated exposure to PBDEs results in accumulation of these chemicals in the body, the Panel estimated the body burden at the BMDL in rodents, and the chronic intake that would lead to the same body burden in humans. For the remaining six congeners no studies were available to identify Reference Points. The Panel concluded that there is scientific basis for inclusion of all 10 congeners in a common assessment group and performed a combined risk assessment. The Panel concluded that the combined margin of exposure (MOET) approach was the most appropriate risk metric and applied a tiered approach to the risk characterisation. Over 84,000 analytical results for the 10 congeners in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary Lower Bound exposure to PBDEs were meat and meat products and fish and seafood. Taking into account the uncertainties affecting the assessment, the Panel concluded that it is likely that current dietary exposure to PBDEs in the European population raises a health concern.

Non-invasive biomonitoring of infant exposure to environmental organic pollutants in north-western Spain based on hair analysis. Identification of potential sources

Recent years have seen growing interest in hair sample analysis to detect organic pollutants (OPs). This biological matrix can be analysed non-invasively for biomonitoring of OPs over a wide exposure window. Obtaining hair sample amounts that meet the needs of the analytical methodology required for the determination of the POs of interest can be challenging, especially in infants. As a result, studies assessing organic pollutants in infant hair have been very scarce. We quantified levels of about 60 OPs, including persistent organic pollutants (POPs), in 110 hair samples from a patient cohort (60 mothers and 50 infants) from Santiago de Compostela (north-western Spain). For each participant we examined relationship between OP levels and corresponding epidemiological parameters using correlations, principal component analysis (PCA), hierarchical cluster analysis, and Multivariate analysis of variance (MANOVA). For many OPs we observed significant correlations with place of residence, parity, and maternal age, as well as pet ownership. Evaluation of dietary habits showed significant associations between levels some OPs and the consumption of fish, molluscs, and cereal. There were significant associations between chlorpyrifos and deltamethrin levels and infant birth characteristics such as birthweight and head circumference. Relations between OP levels in the hair of mothers and their infants were also examined, revealing common sources of exposure for dioxin-like polychlorinated biphenyls (DLPCBs), non-dioxin-like polychlorinated biphenyls (NDLPCBs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs). Levels of fluoranthene (F), pyrene (P), endrin, and some PBDEs in maternal hair were significantly correlated with those in infant hair. Our findings identified common sources of exposure to OPs of distinct chemical classes.

A Critical Review on the Opportunity to Use Placenta and Innovative Biomonitoring Methods to Characterize the Prenatal Chemical Exposome

Adverse effects associated with chemical exposures during pregnancy include several developmental and reproductive disorders. However, considering the tens of thousands of chemicals present on the market, the effects of chemical mixtures on the developing fetus is still likely underestimated. In this critical review, we discuss the potential to apply innovative biomonitoring methods using high-resolution mass spectrometry (HRMS) on placenta to improve the monitoring of chemical exposure during pregnancy. The physiology of the placenta and its relevance as a matrix for monitoring chemical exposures and their effects on fetal health is first outlined. We then identify several key parameters that require further investigations before placenta can be used for large-scale monitoring in a robust manner. Most critical is the need for standardization of placental sampling. Placenta is a highly heterogeneous organ, and knowledge of the intraplacenta variability of chemical composition is required to ensure unbiased and robust interindividual comparisons. Other important variables include the time of collection, the sex of the fetus, and mode of delivery. Finally, we discuss the first applications of HRMS methods on the placenta to decipher the chemical exposome and describe how the use of placenta can complement biofluids collected on the mother or the fetus.

Effects of polycyclic aromatic hydrocarbons (PAHs) on pregnancy, placenta, and placental trophoblasts

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants that are carcinogenic, mutagenic, endocrine-toxic, and immunotoxic. PAHs can be found in maternal and fetal blood and in the placenta during pregnancy. They may thus affect placental and fetal development. Therefore, the exposure levels and toxic effects of PAHs in the placenta deserve further study and discussion. This review aims to summarize current knowledge on the effects of PAHs and their metabolites on pregnancy and birth outcomes and on placental trophoblast cells. A growing number of epidemiological studies detected PAH-DNA adducts as well as the 16 high-priority PAHs in the human placenta and showed that placental PAH exposure is associated with adverse fetal outcomes. Trophoblasts are important cells in the placenta and are involved in placental development and function. In vitro studies have shown that exposure to either PAH mixtures, benzo(a)pyrene (BaP) or BaP metabolite benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE) affected trophoblast cell viability, differentiation, migration, and invasion through various signaling pathways. Furthermore, similar effects of BPDE on trophoblast cells could also be observed in BaP-treated mouse models and were related to miscarriage. Although the current data show that PAHs may affect placental trophoblast cells and pregnancy outcomes, further studies (population studies, in vitro studies, and animal studies) are necessary to show the specific effects of different PAHs on placental trophoblasts and pregnancy outcomes.

Development of a Methodology for Determination of Dioxins and Dioxin-like PCBs in Meconium by Gas Chromatography Coupled to High-Resolution Mass Spectrometry (GC-HRMS)

An analytical strategy was applied to investigate polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dl-PCBs) in newborn meconium samples. The methodology includes extraction by selective pressurized liquid extraction (SPLE), followed by a clean-up multicolumn step. The samples were injected by gas chromatography coupled to a high-resolution mass spectrometer (GC-HRMS). The surrogate recoveries ranged from 68% to 95%, and the average of the limit of quantification (LOQ) ranged from 0.03 to 0.08 pg g^-1 wet weight (ww) for PCDD/Fs and 0.2 to 0.88 pg g^-1 ww for dl-PCBs. The strategy was applied to 10 samples collected in Valencia (Spain) in 2022. In total, 18 out of 29 analysed congeners were detected in at least one sample, whereas 6 of them were detected in all the samples (OCDD, PCB-123, PCB-118, PCB-105, PCB-167, and PCB-156). The levels for the sum of the 17 congeners of PCDD/Fs and 12 congeners of dl-PCBs in the upper-bound (UB), expressed as picograms of toxic equivalency quantity (TEQ) per gram of ww, ranged from 0.19 to 0.31 pg TEQ g^-1 ww.

Pesticides exposure in pregnant Argentinian women: Potential relations with the residence areas and the anthropometric neonate parameters

Intrauterine environment is the first chemical exposure scenario in life, through transplacental transfer. In this study, the aim was to determine concentrations of organochlorine pesticides (OCPs) and selected current use pesticides in the placentas of pregnant women from Argentina. Socio-demographic information, the mother's lifestyle and neonatal characteristics were also analysed and related to pesticides residue concentrations. Thus, 85 placentas were collected at birth, from an area of intensive fruit production for the international market, in Patagonia Argentina. Concentrations of 23 pesticides including, trifluralin (herbicide), the fungicides chlorothalonil and HCB, and the insecticides chlorpyrifos, HCHs, endosulfans, DDTs, chlordanes, heptachlors, drins and metoxichlor, were determined by GC-ECD and GC-MS. Results were first analysed all together and then grouped by their residential settings, in urban and rural groups. Total mean pesticide concentration was 582.6 ± 1034.4 ng/g lw, where DDTs (325.9 ± 950.3 ng/g lw) and chlorpyrifos (188.4 ± 365.4 ng/g lw) showed a high contribution. Pesticide levels found exceeded those reported in low, middle and high income countries from Europe, Asia and Africa. In general, pesticides concentrations were not associated with neonatal anthropometric parameters. When the results were analysed by residence place, significantly higher concentrations of total pesticides and chlorpyrifos (Mann Whitney test p = 0.0003 and p = 0.032, respectively) were observed in placentas collected from mothers living in rural settings compared to urban areas. Rural pregnant women presented the highest pesticide burden (5.9 μg), where DDTs and chlorpyrifos were the major constituents. These results suggested that all pregnant women are highly exposed to complex pesticide mixtures, including banned OCPs and the widely used chlorpyrifos. Based on the pesticide concentrations found, our results warn of possible health impacts from prenatal exposure through transplacental transfer. This is one of the first reports of both chlorpyrifos and chlorothalonil concentrations in placental tissue, and contributes to the knowledge of current pesticide exposure in Argentina.

Biomonitoring of organic pollutants in pet dog plasma samples in North-Western Spain

Most of organic pollutants (OPs) have the ability to interfere with biological systems causing negative effects in living beings, including humans. In the last decades, pets have been used as bioindicators of human exposure because they share the same habitat with their homeowners. We sought to determine levels of approximately 70 OPs, including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated biphenyl ethers (PBDEs), organophosphate pesticides (OPPs), polycyclic aromatic hydrocarbons (PAHs) and pyrethroids (PYRs) in plasma samples from 39 pet dogs from Ourense (north-western Spain). The results revealed that PAHs were the dominant OPs (mean value 175 ± 319 ng/g lipid weight (lw)), followed by PYRs (132 ± 352 ng/g lw), PCBs (122 ± 96 ng/g lw), OCPs (33 ± 17 ng/g lw), PBDEs (19 ± 18 ng/g lw) and OPPs (2.1 ± 2.7 ng/g lw) in plasma samples. We have previously detected the target OPs in hair samples of pets, collected simultaneously and similar trend of some OPs has been observed. Moreover, pyrene and chrysene showed correlations between levels detected in both matrices.

Postnatal exposure to organic pollutants in maternal milk in north-western Spain

Evaluation of postnatal exposure to organic pollutants is especially important for suckling infants during breastfeeding, a crucial perinatal growth period when organs and hormonal systems develop. We determined levels of 60 pollutants, including organochlorine pesticides (OCPs), organophosphorus pesticides (OPPs), pyrethroids (PYRs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and polybrominated diphenyl ethers (PBDEs), in 81 breast milk samples from breastfeeding mothers from Santiago de Compostela (north-western Spain). For most detected organic pollutants, levels were correlated with the season of milk sampling, maternal age at delivery, and place of residence. Dietary consumption habits (eggs, molluscs, and vegetable oils) were also correlated with OCP, OPP, PCB, PBDE and PYR levels. We also assessed the risk to infant health of exposure to organic pollutants in breast milk. PAHs, OCPs, OPPs, and PYRs accounted for almost 95% of the targeted organic pollutants in the samples analysed.

Fetal exposure to organic contaminants revealed by infant hair: A preliminary study in south China

Fetal exposure to multiple organic contaminants (OCs) is a public concern because of the adverse effects of OCs on early life development. Infant hair has the potential to be used as an alternative matrix to identify susceptible fetuses, owing to its reliability, sensitivity, and advantages associated with sampling, handling, and ethics. However, the applicability of infant hair for assessing in utero exposure to OCs is still limited. In this study, 57 infant hair samples were collected in Guangzhou, South China, to evaluate the levels and compositions of typical OCs in the fetus. Most of the target OCs were detected in infant hair, with medians of 144 μg/g, 17.7 μg/g, 192 ng/g, 46.9 ng/g, and 1.36 ng/g for phthalate esters (PAEs), alternative plasticizers (APs), organophosphorus flame retardants (OPFRs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCPs), respectively. Meanwhile, paired maternal hair (0-9 cm from the scalp) was collected to examine the associations between maternal and infant hair for individual compounds. Low-brominated PBDEs tended to deposit in infant hair, with median concentrations approximately two times higher than those in maternal samples. Levels of PBDEs and 4,4'-dichlorodiphenyldichloroethylene (p,p'-DDE) in paired maternal and infant hair showed strong positive correlations (p < 0.05), while most plasticizers (PAEs and APs) were poorly correlated between paired hair samples. Exposure sources were responsible for the variation in correlation between OC levels in the paired infant and maternal samples. Crude relationships between fetal exposure to OCs and birth size were examined using the Bayesian kernel machine regression (BKMR) model. BDE-28 was found to be adversely associated with the birth size. This study provides referential information for evaluating in utero exposure to OCs and their health risks based on infant hair.

Live in same region, respond differently: Canine and human response to pollutants in placental accumulation

Polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs) are endocrine-disrupting chemicals (EDCs). Their presence in the environment is particularly concerning in cases of fetal exposure, which is the most vulnerable period of life for both human and animals who share the same environment. Placenta, as a sample collected using noninvasive methods to screen EDCs, is a good indicator for potential fetal exposure. Although recent studies indicate that companion animal may correspond to human exposure, species-specific anatomo-morphological and metabolic differences are controversial. In this study, placenta samples of 60 women and 25 dogs living and giving birth within the same region were evaluated for the presence of PCB, OCP, PBDE, and PAH residues; where, socio-demographic factors were also assessed to identify the possible sources. Gas chromatography-mass spectrometry method was validated for the matrix, and among 45 screened and targeted pollutants, only 18 were found in human placentas. While the most frequently detected pollutants were DDTs, followed by PAHs and PCBs in decreasing order, the pollutants with the highest concentrations were PAHs, followed by PCBs and DDTs. Only five of the target contaminants were detected in the dog placentas. These results indicate that; as dogs have different bioaccumulation capacities and higher excretion rates than humans, the life-long effects of exposure to endocrine compound and possible consequences related to adverse health outcomes are expected to vary and concentrations cannot be directly correlated.

Maternal and fetal tissue distribution of α-cypermethrin and permethrin in pregnant CD-1 mice

Pyrethroid insecticides are widely used throughout agriculture and household products. Recent studies suggest that prenatal exposure to these insecticides may adversely affect fetal development; however, little is known about the distribution of these chemicals in pregnant animals. The present study aimed to address this gap in knowledge by investigating the distribution of two commonly used pyrethroid insecticides, permethrin and α-cypermethrin, in maternal and fetal tissues of pregnant CD-1 mice. Dams were dosed from gestational days 6 to 16 via oral gavage with permethrin (1.5, 15, and 50 mg/kg), α-cypermethrin (0.3, 3, and 10 mg/kg), or corn oil vehicle. Pyrethroid levels were determined in gestational day 16 tissues collected 90 min after the final dose was administered. Across maternal tissues, levels of both pyrethroids were the highest in maternal ovaries, followed by liver and brain, respectively. In addition, levels of both pyrethroids in maternal tissues and placenta were significantly higher than those in the fetal body and amniotic fluid, suggesting that these compounds may exhibit low transfer across the mouse placenta. While additional toxicokinetic studies are needed to verify the time course of pyrethroids in the fetal compartment, these findings support investigation into indirect modes of action relevant to the effects of pyrethroids on mammalian fetal development.

Pesticides analysis in alternative biological matrices

This review aims to bring together the works on pesticide analysis in alternative biological matrices, such as hair, breast milk, meconium, and placenta. Much is known about the harmful effects of the use and indirect consumption of pesticides; however, the assessment of long-term contamination is still unclear. In this sense, the use of hair as an alternative biological matrix has some advantages, such as segmentation, which makes it possible to assess the presence of xenobiotics to which individuals have been exposed over the years, and possibly relate this exposure to symptoms or diseases that may affect them. Complementarily, the other matrices discussed are able to provide information about the exposure of mothers and newborn children, who may have been indistinctly exposed to pesticides while in the womb. Through the analysis of studies already performed, it can be observed that organochlorine pesticides (OCPs) are the most likely to be found within the biological matrices discussed here, due to the lipophilic characteristics of these compounds. For the other classes, biotransformation products are more easily detected.

A narrative review of converging evidence addressing developmental toxicity of pyrethroid insecticides

Pyrethroid insecticides are broadly used in agriculture and household products throughout the world. Exposure to this class of insecticides is widespread, and while generally believed to be safe for use, there is increasing concern regarding their effects on neurodevelopment. Due to the critical roles that molecular targets of pyrethroids play in the regulation of neurodevelopment, particular focus has been placed on evaluating the effects of in utero and childhood pyrethroid exposure on child cognition and behavior. As such, this narrative review synthesizes an assessment of converging study types; we review reports of neonatal pyrethroid levels together with current epidemiological literature that convergently address the risk for developmental toxicity linked to exposure to pyrethroid insecticides. We first address studies that assess the degree of direct fetal exposure to pyrethroids in utero through measurements in cord blood, meconium, and amniotic fluid. We then focus on the links between prenatal exposure to these insecticides and child neurodevelopment, fetal growth, and other adverse birth outcomes. Furthermore, we assess the effects of postnatal exposure on child neurodevelopment through a review of the data on pediatric exposures and child cognitive and behavioral outcomes. Study quality was evaluated individually, and the weight of evidence was assessed broadly to characterize these effects. Overall, while definitive conclusions cannot be reached from the currently available literature, the available data suggest that the potential links between pyrethroid exposure and child neurodevelopmental effects deserve further investigation.

Associations Between Polybrominated Diphenyl Ethers Concentrations in Human Placenta and Small for Gestational Age in Southwest China

BACKGROUND

Prenatal exposures to polybrominated diphenyl ethers (PBDEs) may affect fetal growth. Small for gestational age (SGA) is a measure based on birth weight and gestational age at birth and represents a good indicator of fetal growth but it has been used only in a small number of studies. The present study aimed to examine the associations between PBDEs exposure and the risk of SGA among participants from a birth cohort in Southwest China.

METHODS

The concentrations of eight common PBDE congeners (BDE-28, BDE47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209) in 996 human placental samples collected between May to October 2020 were determined. A questionnaire survey was administered regarding maternal characteristics. The outcome data of the newborns were obtained from the medical record. The Mann-Whitney U test and binomial logistic regression analysis were used to assess associations between PBDEs concentrations (as a continuous or categorical variable) and SGA.

RESULTS

All PBDE congeners were detected in more than 73% of samples. The median concentrations of ΣPBDEs were 10.08 ng/g lipid weight (lw). BDE-209 was the most abundant PBDE congener, contributed 28% to ΣPBDEs. There were 114 (11.4%) SGA infants. The levels of BDE-99, BDE-100, BDE-209, and the total levels of ΣPBDEs in the SGA group were significantly higher than those in the controls. When classifying the PBDEs concentrations as two categories: low and high, high level of ΣPBDEs was associated with increased risk of SGA [odds ratio (OR): 2.203, 95% confidence interval (CI): 1.453-3.340] after adjusting for potential covariates. The association remained significant when stratifying the data by gender of the newborn (OR: 2.572, 95% CI: 1.337-4.947 for boys; OR: 2.385, 95% CI: 1.315-4.325 for girls).

CONCLUSION

The present study adds to the literature by using placenta to measure PBDEs exposure during pregnancy, and provides evidence that prenatal exposure to PBDEs may be associated with the risk of SGA, at least at the levels of exposure in our population.

The role of adipose tissue analysis on Environmental Pollutants Biomonitoring in women: The European scenario

Humans are exposed every day to assorted environmental pollutants namely, polychlorinated biphenyls (PCB), organochlorine pesticides (OCP), brominated flame-retardants (BFR), polycyclic aromatic hydrocarbons (PAH), synthetic musks, heavy metals (e.g. cadmium) and plastic additives (e.g. bisphenol A, BPA). Besides environmental persistence, biomagnification and bioaccumulative properties, these pollutants are classified as endocrine disruptors (EDs), metabolic disruptors, neurologic disruptors. These compounds affect the normal function of several mechanisms in the human body being linked to human health issues as cancer development (e.g. breast, uterine and endometrial), miscarriage, birth defects, premature delivery and infertility. In order to prevent future health issue of women and possible progeny, the assessment of EDs accumulated is essential, particularly in adipose tissue. These samples have been referred as the ideal matrix to establish over time accumulation and long-term exposure of persistent and non-persistent lipophilic EDs. However, the invasive sample collection procedure and methodology processing discourages the usage of this matrix for biomonitoring studies. In this review, a Web of Science search without any publishing year restriction on the analysis in adipose tissue of PCB, OCP, BPA, cadmium, BFR and synthetic musks was performed. A total of 313 studies were found, 158 were European studies from which the studies with data on women EDs accumulation were selected for detailed analysis (n = 90). The results were structured and presented in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The present paper is an overview on the existent EDs analytical methods and levels accumulated in women adipose tissue, with the correspondent health implications across Europe. The limits of detection and quantification were compared and a discussion with results obtained about the presence of ED was performed.

Fetoplacental vasculature as a model to study human cardiovascular endocrine disruption

Increasing evidence has associated the exposure of endocrine-disrupting chemicals (EDCs) with the cardiovascular (CV) system. This exposure is particularly problematic in a sensitive window of development, pregnancy. Pregnancy exposome can affect the overall health of the pregnancy by dramatic changes in vascular physiology and endocrine activity, increasing maternal susceptibility. Moreover, fetoplacental vascular function is generally altered, increasing the risk of developing pregnancy complications (including cardiovascular diseases, CVD) and predisposing the foetus to adverse health risks later in life. Thus, our review summarizes the existing literature on exposures to EDCs during pregnancy and adverse maternal health outcomes, focusing on the human placenta, vein, and umbilical artery associated with pregnancy complications. The purpose of this review is to highlight the role of fetoplacental vasculature as a model for the study of human cardiovascular endocrine disruption. Therefore, we emphasize that the placenta, together with the umbilical arteries and veins, allows a better characterization of the pregnant woman's exposome. Consequently, it contributes to the protection of the mother and foetus against CV disorders in life.

Determination of organic pollutants in meconium and its relationship with fetal growth. Case control study in Northwestern Spain

OBJECTIVES

Antenatal exposure to organic pollutants is a leading public health problem. Meconium is a unique matrix to perform prenatal studies because it enables us to retrospectively evaluate fetal exposure accumulated during the second and third trimester. The aim of the present study was to evaluate associations between organic pollutant levels in meconium and birth weight in NW Spain.

METHODS

In this study, we quantify the concentrations of 50 organic pollutants together with the total values of the most important chemical groups in meconium using gas chromatography coupled to tandem mass spectrometry.

RESULTS

Organochlorine pesticides, polychlorinated biphenyls and polybrominated diphenyl ethers were detected with the highest levels in meconium from small for gestational age newborns. It was estimated that several congeners were statistically significant (p<0.05). However, organophosphorus pesticides attained higher concentrations in newborns with an appropriate weight.

CONCLUSIONS

The occurrence of transplacental transfer can be confirmed. Prenatal exposure to organic pollutants was associated with a decrease in birth weight and, therefore, organic pollutants could have an impact on fetal growth. Nevertheless, these results need validation in larger sample sized studies.

Toxic effects of 2,4,4'- trichlorobiphenyl (PCB-28) on growth, photosynthesis characteristics and antioxidant defense system of Lemna minor L

Polychlorinated biphenyls (PCBs) are a common category of persistent man-made organic pollutants that are widespread in the ambient environment. Although Lemna minor L. is an extensively applied plant for aquatic remediation in ecotoxicology research worldwide, little is known regarding its responses to the potentially toxic effects of PCBs. For this study, a 14-day dissolved exposure was conducted to explore the effects of 2,4,4'- trichlorobiphenyl (PCB-28) on the growth, photosynthesis characteristics and antioxidant defense system of L. minor plants. We found that 100 and 200 μg/L of PCB-28 decreased the fresh weight, chlorophyll and protein content, and activities of superoxide dismutase, peroxidase, glutathione S-transferase, and nitroreductase, whereas plasma membrane permeability, and the malondialdehyde and reactive oxygen species concentrations were increased. However, it was observed that 5 and 20 μg/L of PCB-28 had no significant effects on these physiological indices. The ultra-structure of chloroplast demonstrated that 100 and 200 μg/L PCB-28 severely damaged the chloroplast structures. Moreover, correlation analysis revealed that the content of reactive oxygen species had negative correlations with the fresh weight, chlorophyll and protein content, as well as the activities of superoxide dismutase, peroxidase, glutathione S-transferase, and nitroreductase, but had positive correlations with the malondialdehyde content and plasma membrane permeability. This work provides valuable data toward elucidating the physiology and biochemistry of PCBs induced phytotoxicity.

Perinatal effects of persistent organic pollutants on thyroid hormone concentration in placenta and breastmilk

Thyroid hormones (TH) are known to play a critical role in regulating many biological processes including growth and development, energy homeostasis, thermogenesis, lipolysis and metabolism of cholesterol. Severe TH deficiency especially during fetal development results in cretinism, but can also lead to an imbalance in metabolism with, among others, an alteration in body weight composition. Over the past two decades, increasing evidence has shown that certain persistent organic pollutants (POP) can interfere with the endocrine system. These POP referred to as "endocrine disrupting chemicals" are widely present in the environment and populations are exposed globally. Moreover, epidemiological studies have shown that a particularly sensitive period is the pre- and postnatal time. Indeed, perinatal exposure to such chemicals could lead to the onset diseases in later life. It is known, that, maternal thyroid hormones are transported by the placenta to the fetus from 6 weeks of gestation and it seems that during the first trimester, and part of the second, the fetus is entirely dependent on maternal TH supply for its development. Interferences in the TH-network as a consequence of the exposure to such pollutants could cause variations in TH concentration. Only small changes in maternal thyroid hormone levels in early stages of pregnancy can influence fetal neurological and cardiovascular development, as well as according to recent studies, have effect on childhood body composition. With this review, we will report the most recent and important studies concerning the association between thyroid hormone concentration and POP levels measured during the perinatal period. We will mostly focus on the data recently reported on placenta and breastmilk as main sources for understanding the potential consequences of exposure. The possible link between exposure to pollutants, TH dysregulation and possible adverse outcome will also be briefly discussed. From our literature search, several studies support the hypothesis that pre- and postnatal exposure to different pollutants might play a role in causing variation in thyroid hormone concentration. However, few research papers have so far studied the relationship linking exposure to pollutants, TH concentration and possible health consequences. Therefore, this review highlights the need for further research in this direction.

A sensitive bio-barcode immunoassay based on bimetallic Au@Pt nanozyme for detection of organophosphate pesticides in various agro-products

Organophosphate pesticides (OPs) are often used as insecticides and acaricides in agriculture, thus improving yields. OP residues may pose a serious threat, duetoinhibitionof the enzymeacetylcholinesterase(AChE). Therefore, a competitive bio-barcode immunoassay was designed for simultaneous quantification of organophosphate pesticide residues using AuNP signal amplification technology and Au@Pt catalysis. The AuNP probes were labelled with antibodies and corresponding bio-barcodes (ssDNAs), MNP probes coated with ovalbumin pesticide haptens and Au@Pt probes functionalized with the complementary ssDNAs were then prepared. Subsequently, pesticides competed with MNP probes to bind the AuNP probes. The recoveries of the developed assay were ranged from 71.26 to 117.47% with RSDs from 2.52 to 14.52%. The LODs were 9.88, 3.91, and 1.47 ng·kg^-1, for parathion, triazophos, and chlorpyrifos, respectively. The assay was closely correlated with the data obtained from LC-MS/MS. Therefore, the developed method has the potential to be used as an alternative approach for detection of multiple pesticides.

Association between placenta concentrations polybrominated and polychlorinated biphenyls and gestational diabetes mellitus: a case-control study in northwestern Spain

Exposure to persistent organic pollutants begins in uterine life. The study was conducted to evaluate associations between gestational diabetes mellitus and the presence of persistent organic pollutants in placenta samples. They were derived from a birth cohort study in Ourense (NW Spain). Selective pressurized liquid extraction methodologies were used to determine targeted persistent organic pollutants in placenta samples. Cleanup of extracts was performed by solid-phase extraction using EZ-POP cartridges and detection by gas chromatography coupled to tandem mass spectrometry. Statistical calculations were performed by comparing the values obtained in the case and control groups. Statistical significance was considered as p < 0.050. Results: The concentrations of several congeners of polybrominated diphenyl ethers (PBDE) and polychlorinated biphenyls (PCB) presented lower levels in the placentas of expectant mothers with gestational diabetes mellitus when comparing them to the control cohort. This difference was statistically significant. It was revealed that this association was independent of obesity, age, parity, amenorrhoea at birth, or a family history of diabetes mellitus. To the best of our knowledge, this paper reported an inverse relationship between PBDE and PCB levels in placenta and gestational diabetes mellitus for the first time. We believe this may open a door to future studies in this field.