Concentrations of organochlorine pesticides in cord serum of newborns in Wuhan, China

Urinary biomarkers of exposure to organophosphate, pyrethroid, neonicotinoid insecticides and oxidative stress: A repeated measurement analysis among pregnant women

Exposure to insecticides may be associated with increased oxidative stress (OS), but few studies have assessed the associations of OS biomarkers (OSBs) with exposure to multiple insecticides and their mixture, especially in pregnant women who are a vulnerable population. In the present study, 1,094 Chinese pregnant women were recruited and a total of 3,282 urine samples were collected at their three trimesters to measure eight metabolites of organophosphates, three metabolites of pyrethroids, nine typical neonicotinoids/their metabolites, and three OSBs of DNA damage (8-OHdG), RNA damage (8-OHG), and lipid peroxidation (HNE-MA). Among the twenty target insecticide metabolites, sixteen of them were frequently detected; thirteen of them were detected in over 86% of all the urine samples except for imidacloprid (IMI, detection frequency: 72.9%), desnitro-imidacloprid (DN-IMI, 70.0%), and clothianidin (CLO, 79.6%). The reproducibility of their concentrations across the three trimesters was poor to fair (intraclass correlation coefficients <0.50). Multiparity and warm season were related to higher urinary levels of some insecticide metabolites, while higher education level and inadequate weight gain during pregnancy were significantly associated with lower concentrations of certain insecticide metabolites. Linear mixed model analyses suggested that almost all the frequently detected insecticide metabolites [other than 3-phenoxybenzoic acid (3-PBA)] were significantly associated with elevated levels of the three OSBs (8-OHdG, 8-OHG, and HNE-MA), where the percent change (Δ%) ranged 8.10-36.0% for 8-OHdG, 8.49-34.7% for 8-OHG, and 5.92-182% for HNE-MA, respectively, with each interquartile ratio (IQR)-fold increase in the concentrations of the individual exposure biomarkers. Weighted quantile sum models demonstrated that the insecticide metabolite mixture was positively associated with the three OSBs. Overall, urinary desmethyl-clothianidin (DM-CLO) and 3,5,6-trichloro-2-pyridinol (TCPy) were the top insecticide exposure biomarkers contributing to the association with 8-OHdG and 8-OHG levels, while PNP contributed the most to the association with HNE-MA levels. These findings suggested that gestational exposure to organophosphates, pyrethroids, neonicotinoids, their transformation products, and their mixture may increase oxidative damage to lipids, RNA, and DNA during pregnancy.

Comparative in vitro and in silico study on the estrogenic effects of 2,2-bis(4-chlorophenyl)ethanol, 4,4'-dichlorobenzophenone and DDT analogs

DDT and its transformation products (DDTs) are frequently detected in environmental and biological media. Research suggests that DDT and its primary metabolites (DDD and DDE) could induce estrogenic effects by disturbing estrogen receptor (ER) pathways. However, the estrogenic effects of DDT high-order transformation products, and the exact mechanisms underlying the differences of responses in DDT and its metabolites (or transformation products) still remain unknown. Here, besides DDT, DDD and DDE, we selected two DDT high-order transformation products, 2,2-bis(4-chlorophenyl) ethanol (p,p'-DDOH) and 4,4'-dichlorobenzophenone (p,p'-DCBP). We aim to explore and reveal the relation between DDTs activity and their estrogenic effects by receptor binding, transcriptional activity, and ER-mediated pathways. Fluorescence assays showed that the tested 8 DDTs bound to the two isoforms (ERα and ERβ) of ER directly. Among them, p,p'-DDOH exhibited the highest binding affinity, with IC₅₀ values of 0.43 μM and 0.97 μM to ERα and ERβ, respectively. Eight DDTs showed different agonistic activity toward ER pathways, with p,p'-DDOH exhibiting the strongest potency. In silico studies revealed that the eight DDTs bound to either ERα or ERβ in a similar manner to 17β-estradiol, in which specific polar and non-polar interactions and water-mediated hydrogen bonds were involved. Furthermore, we found that 8 DDTs (0.0008-5 μM) showed distinct pro-proliferative effects on MCF-7 cells in an ER-dependent manner. Overall, our results revealed not only for the first time the estrogenic effects of two DDT high-order transformation products by acting on ER-mediated pathways, but also the molecular basis for differential activity of 8 DDTs.

Prenatal exposure to organochlorine pesticides and infant growth: A longitudinal study

BACKGROUND

The association between exposure to organochlorine pesticides (OCPs) and infant growth has been reported contradictorily in previous studies. Few studies have investigated the effects of prenatal exposure to OCPs on infant growth assessed longitudinally at multiple time points.

OBJECTIVES

The purpose of the study was to examine the associations between prenatal exposure to OCPs and infant growth at birth, 6, 12 and 24 months of age, and further to explore the potential sex-specific effects.

METHODS

The study population included 1039 mother-infant pairs who participated in a birth cohort study in Wuhan, China. The weight, length and body mass index (BMI) z-score of infants were measured and calculated at birth, 6, 12 and 24 months of age. The overweight status was defined as BMI z-score ≥ 85th percentile according to the standard of World Health Organization. The concentrations of OCPs were measured in cord serum, including hexachlorocyclohexanes (HCHs, consisted of α-HCH, β-HCH, and γ-HCH), p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) and its metabolites: p,p'-dichlorodiphenyldichloroethane (p,p'-DDD), and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE). Generalized linear models were applied to estimate the associations of cord OCPs with infant growth parameters. A group-based semiparametric mixture model was used to estimate growth patterns of infants. Linear-mixed growth curve models were used to examine relationships between predicted growth trajectories and prenatal exposure to OCPs. Weighted quantile sum regression (WQSR) analyses were used to estimate the mixture effects of OCPs on infant growth.

RESULTS

Higher cord serum β-HCH concentrations were associated with higher BMI z-score at 12 [β = 0.07, 95%CI: 0.01, 0.13] and 24 months of age [β = 0.08, 95% CI: 0.02, 0.14]. Similar patterns were observed for relationships of γ-HCH [β = 0.04, 95%CI: 0.01, 0.07] and p,p'-DDT [β = 0.03, 95% CI: 0.00, 0.06] with BMI z-score at 6 and 12 months of age, respectively. However, higher cord serum p,p'-DDE concentrations were associated with a reduction of BMI z-score at 6 months of age [β = -0.07, 95% CI: -0.12, -0.01]. Cord serum β-HCH was also positively associated with the risk of overweight at 12 months of age [RR = 1.16, 95% CI (1.02, 1.33), for the medium vs the lowest tertile]. Among girls, the effects of β-HCH on BMI z-score and overweight status were stronger than boys at 12 and 24 months of age. No statistically significant relationships of other OCPs with infant growth were observed.

CONCLUSIONS

Prenatal exposure to β-HCH was associated with increased BMI z-score and higher risk of overweight status in infants especially at 12 and 24 months of age, which seemed to be stronger in girls.

Occurrence of Organochlorine Pesticides in Human Tissues Assessed Using a Microextraction Procedure and Gas Chromatography-Mass Spectrometry

This work focuses on the development, validation and application of an analytical method for the determination of twenty organochlorine pesticides (OCPs) in human tissues using salting-out liquid-liquid extraction and dispersive liquid-liquid microextraction for sample preparation and gas chromatography-mass spectrometry to analyze the obtained extracts. Measurement of the concentration levels of these toxics in tissues can be used to assess the risk of the population to exposure. The linearity of the proposed method was verified in the 10-1,000 ng/g range. The sensitivity was evaluated calculating the limits of detection (LODs) for 20 OCPs (α-, β-, γ- and δ-hexachlorocyclohexane (HCH), α- and β-endosulfan, endosulfan sulfate, aldrin, dieldrin, endrin, endrin ketone, endrin aldehyde, α- and γ-chlordane, 4,4'-dichlorodiphenyltrichloroethane, 4,4'-dichlorodiphenyldichloroethylene (DDE), 4,4'-dichlorodiphenyldichloroethane, heptachlor, heptachlor epoxide and methoxychlor), most of them being found between 1.0 and 16 ng/g. The intra- and interday precisions were <12% for relative standard deviation values. The accuracy of the method was evaluated by recovery studies, which gave recovery percentages in the 85-109% range. Seven different tissues (liver, kidney, heart, spleen, lung, brain and abdominal fat) from eight autopsies were analyzed, and only three cases were seen to have β-HCH and 4,4'-DDE in abdominal fat, while 4,4'-DDE was also detected in the heart of one case. The rest of the samples were free of the studied OCPs at least above the corresponding LODs.

Gene-environment interactions between GSTs polymorphisms and targeted epigenetic alterations in hepatocellular carcinoma following organochlorine pesticides (OCPs) exposure

Exposure to environmental pollutant organochlorine pesticides (OCPs) and the role of tumour suppressor GSTs gene polymorphisms as well as epigenetic alterations have all been well reported in hepatocarcinogenesis. However, the interplay between environmental risk factors and polymorphic tumour suppressor genes or epigenetic factors in hepatocellular carcinoma (HCC) development remains ambiguous. Herein, we investigated the relationship of three GSTs polymorphisms (GSTT1 deletion, GSTM1 deletion, GSTP1 rs1695) as well as GSTP1 promoter region DNA methylation and HCC risk with a particular focus on the interaction with OCPs exposure among 90 HCC cases and 99 controls in a Chinese population. Serum samples were analysed for OCPs exposure employing gas chromatography coupled with mass selective detector (GC-MS). GSTs polymorphisms and epigenetic alterations were determined using high-resolution melting PCR (HRM PCR) and DNA sequencing. After adjusting for confounders (HBV infection, smoking, alcohol consumption, BMI, age, gender), OCPs exposure and GSTP1 methylation is significantly associated with elevated risk of HCC, while no significance is observed for GSTs polymorphisms. Moreover, the effects of OCPs exposure on HCC risk are more pronounced amongst GSTP1 (Ile/Val + Val/Val) and GSTP1 promoter methylation subjects than those who were GSTP1 (Ile/Ile) and unmethylated subjects. The interactions between OCPs exposure and GSTP1 genotype as well as GSTP1 epigenetic status are statistically significant. The current study demonstrates the importance of gene-environment interactions in the multifactorial development of HCC.

Effective biodegradation of pentachloronitrobenzene by a novel strain Peudomonas putida QTH3 isolated from contaminated soil

To eliminate pentachloronitrobenzene (PCNB) residue in PCNB-contaminated environment, the degradation potential of Pseudomonas putida QTH3 to PCNB was evaluated in this study. Peudomonas putida QTH3 could grow well in mineral salt medium (MSM) containing PCNB as sole carbon and was able to degrade PCNB efficiently, whereas the degradation rate of P. putida QTH3 to PCNB increased gradually, and reached 49.84% in 35 days. The degradation rates of P. putida QTH3 to 13 tested organochlorine compounds found to be 10.85%-42.51% after 14 days. The metabolites during PCNB biodegradation by P. putida QTH3 were identified as catechol, 2, 3, 5, 6-tetrachloroaniline (TCA), 2, 3, 4, 5- TCA, 2, 3, 4, 5, 6-pentachloroaniline (PCA) and pentachlorothioanisole (PCTAs). Furthermore, possible degradation pathway of PCNB by P. putida QTH3 was proposed. The degradation rates of intracellular enzyme and extracellular enzyme were 44.73% and 8.93% after incubation with 100 mg L^-1 PCNB for 30 min, respectively. Thus, intracellular enzyme is a major enzyme responsible for PCNB degradation. The results indicate that P. putida QTH3 can be a suitable organism for the degradation of PCNB, and facilitate its potential for the bioremediation of the environments contaminated with major organochlorine compounds used during this study.

Pectin reduces environmental pollutant-induced obesity in mice through regulating gut microbiota: A case study of p,p'-DDE

BACKGROUND

The prevalence of obesity has raised global concerns. Environmental pollutants are one of the main causes of obesity. Many studies have demonstrated that dietary fiber could reduce obesity induced by high-fat diets, but whether environmental pollutant-induced obesity can be reversed is still unknown.

OBJECTIVES

This study aimed to investigate the effects of pectin on obesity induced by a typical environmental pollutant p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and explore the underlying mechanism by which pectin reversed p,p'-DDE-induced obesity.

METHODS

p,p'-DDE was used to induce obesity in C57BL/6J mice and pectin was supplied during and after cessation of p,p'-DDE exposure. Body and fat weight gain, plasma lipid profile and insulin resistance of mice were assessed. Gut microbiota composition and the levels of short-chain fatty acids (SCFAs) as well as the receptor proteins and hormones in the SCFAs-related signaling pathway were analyzed. Moreover, p,p'-DDE levels in various tissues of mice were detected.

RESULTS

Pectin supplementation reversed body and fat weight gain, dyslipidemia, hyperglycemia and insulin resistance in p,p'-DDE-exposed mice. Furthermore, pectin apparently altered the p,p'-DDE-induced microbial composition and then promoted the levels of SCFAs in colonic feces as well as the expression of G-protein coupled receptors and the concentration of hormone peptide YY (PYY) and glucagon like peptide-1 (GLP-1). Pectin treatment also significantly reduced p,p'-DDE accumulation in mice tissues during p,p'-DDE exposure but did not change p,p'-DDE metabolism after termination of p,p'-DDE exposure.

CONCLUSIONS

Pectin had a good effect on reducing p,p'-DDE-induced obesity through regulating gut microbiota and provided a potential strategy for the treatment of environmental pollutant-caused health problems.

Association of in utero hexachlorocyclohexane exposure with gestational age

As endocrine disrupting chemicals, hexachlorocyclohexane (HCH) isomers were reported to impair the intrauterine growth. Although the findings of HCHs with preterm birth were well established, the associations with gestational age were limited. In the present study, we examined whether exposure to HCHs would influence gestational age. The study population included 1028 pregnant women and their offspring who were born in 2014-2015 from a birth cohort in Wuhan, China. Associations of the cord serum HCH levels with gestational age were estimated using generalized linear models. We found higher HCH levels in pregnant women, who were elder, had higher body mass index (BMI) before pregnancy, received higher education, or were exposed to smoking passively. For term birth, the 3rd tertiles of α-HCH and γ-HCH were significantly associated with shorter gestational age [crude β = -1.017, confidence interval (CI): - 2.017, - 0.018 for α-HCH, crude β = -1.068, CI: - 2.067, - 0.070 for γ-HCH], and relationships were similar after adjusted by covariates. Stratified analysis showed positive associations between α-HCH and gestational age for mothers younger than 25 years old (adjusted β = 0.610, CI: 0.061, 1.158), while showing negative relationships for mothers elder than 35 years old (adjusted β = -1.365, CI: -2.414, -0.317). In summary, our results indicated cord serum levels of HCHs were associated with gestational age at birth.

Association of prenatal exposure to organochlorine pesticides and birth size

There has been substantial evidence showing the adverse effects of organochlorine pesticide (OCP) exposure on human, but studies focused on the prenatal exposure effects at low OCP levels on infant birth size were scarce and controversial. In this study, cord serum samples were collected at the delivery from 1028 pairs of mothers and newborns in Wuhan, China and investigated the associations of prenatal exposure to OCPs and birth size. The prenatal exposure of hexachlorocyclohexane isomers (HCHs), p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) and its metabolites were analyzed. The associations between birth size and prenatal OCP exposure were examined by multiple linear regressions. A sex-specific relationship between the OCP exposure and birth size was observed. β-HCH was negatively associated with birth weight and ponderal index for boys [adjusted β = -28.61; 95% confidence interval (CI): -54.84, -4.37 and adjusted β = -0.17; 95% CI: -0.32, -0.01, respectively], whilst no significant associations with prenatal exposure of OCPs were found among girls. The inverse association of prenatal exposure to low levels of β-HCH was shown sex-specific difference, which was only observed significantly in boys. The findings strengthened the evidence that the fetal development was influenced by prenatal exposure to certain OCPs and the effects might be different in the newborn sex.