Measurement of hair thyroid and steroid hormone concentrations in the rat evidence endocrine disrupting potential of a low dose mixture of polycyclic aromatic hydrocarbons

Polycyclic Aromatic Hydrocarbons (PAHs) in Freshwater Systems: A Comprehensive Review of Sources, Distribution, and Ecotoxicological Impacts

This comprehensive review offers new perspectives on the distribution, sources, and ecotoxicological impacts of polycyclic aromatic hydrocarbons (PAHs) in freshwater systems. Unlike previous reviews, this work integrates recent findings on PAH dynamics within environmental matrices and emphasizes spatiotemporal variability across geographic regions. It critically examines both anthropogenic and natural sources, as well as the physical, chemical, and biological mechanisms driving PAH transport and fate. Special attention is given to the ecotoxicological effects of PAHs on freshwater organisms, including bioaccumulation, endocrine disruption, and genotoxicity. Notably, this review identifies key knowledge gaps and proposes an interdisciplinary framework to assess ecological risk and guide effective monitoring and management strategies for the protection of freshwater ecosystems.

Urinary metabolic alterations associated with occupational exposure to metals and polycyclic aromatic hydrocarbons based on non-target metabolomics

Long-term occupational exposure to metals and organics have been reported to be under great health risks. However, limited data are available on the molecular mechanism between combined exposure to metals and polycyclic aromatic hydrocarbons (PAHs) and harmful health effects. In present work, non-target metabolomics study was conducted based on urine samples from nonferrous metal smelting workers (n = 207), surrounding residents (n = 180), and the control residents (n = 187) by using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS). Differential and correlation analyses among metabolic features indicate that total 22 differential metabolites in smelting workers were associated (p < 0.05) with metal and PAH exposure. Particularly, amino acid metabolism was strongly disturbed, and other metabolic pathways, including steroid hormone biosynthesis, citrate cycle, and pantothenate and coenzyme A (CoA) biosynthesis were also perturbed. Among them, steroid hormone biosynthesis was more affected by PAH exposure than metals, especially for hydroxyphenanthrene. These altered pathways were closely associated with oxidative stress, inflammation, and energy metabolism disorder. Additionally, our results indicate that endogenous metabolism in surrounding residents were also affected by nonferrous metal smelting activities to some extent. Our work provides valuable insights into molecular mechanisms of adverse health effects probably induced by combined exposure to metals and PAHs.

Association of urinary metabolites of polycyclic aromatic hydrocarbons with urinary incontinence in adults: A cross-sectional study

This study aims to investigate the association between polycyclic aromatic hydrocarbon (PAH) metabolites and urinary incontinence (UI) in the general adult population. This study analyzed six urinary PAH metabolites in the general adult population from the 2005-2016 National Health and Nutrition Examination Survey (NHANES). UI was distinguished into stress UI (SUI), urgency UI (UUI), mixed UI (MUI), and any UI by self-reported questionnaires. Multiple logistic regression, restricted cubic spline (RCS) regression, and quantile g-computation (QG-C) were applied to assess the association between PAHs (individual and mixture exposure) and the prevalence of UI. A total of 8,136 participants were included in our study. The participants had a median age of 45.9 years, and 48.7 % of individuals were female. Most ln-transformed PAHs were positively and linearly related to the prevalence of SUI and any UI in women (P < 0.05). Increasing prevalence of SUI was associated with the highest quantiles of 3-hydroxyfluorene (3-FLU) (OR = 1.72, 95%CI = 1.27-2.33, P for trend = 0.002), 2-hydroxyfluorene (2-FLU) (OR = 1.75, 95%CI = 1.29-2.38, P for trend = 0.008), and 1-hydroxypyrene (1-PYR) (OR = 1.44, 95%CI = 1.05-1.96, P for trend = 0.012) compared with the lowest quantiles in women. The mixture of urinary PAH metabolites was significantly associated with an increased prevalence of SUI (OR = 1.09, 95%CI: 1.01-1.19, P = 0.038) in women. Urinary 2-FLU had the greatest positive contribution to the overall effect, while 2-hydroxynapthalene (2-NAP) was the major negative contributor. Our study demonstrated that mixture exposure to PAHs is associated with the prevalence of SUI in adult women, which might be primarily driven by 2-FLU.

Residual levels of dietary deltamethrin interfere with growth and intestinal health in Litopenaeus vannamei

To date, few study explored the damage of chronic dietary exposure to the lipophilic pesticide deltamethrin (DM) in aquatic animals, and it remains unclear whether its toxicity and residue levels would be affected by dietary lipid levels. Therefore, the present study aimed to elucidate the interactions between dietary lipid levels and DM levels in the Pacific white shrimp, focusing on growth performance, antioxidant capacity, and intestinal microbiota. DM has excellent insecticidal activity and has been used worldwide. Previous research has shown that environmental DM poses toxicity risks to aquatic animals. Six different diets were formulated to feed shrimp for 6 weeks with two lipid levels (6.96 %, 10.88 %) and three DM levels (0.2 mg·kg-1, 1 mg·kg-1, 5 mg·kg-1), namely LF0.2, LF1, LF5, HF0.2, HF1, HF5, respectively. Each diet was assigned to three net cages with a total of 18 cages (40 shrimp per tank, average weight (0.382±0.001 g), of which 0.2 mg·kg-1, are grouped in environmental DM control groups. The growth of shrimp was reduced as the dietary DM levels increased. When shrimp were fed a diet containing a high dose of DM, a reduction in their antioxidant capacity was also observed. Enzyme activity and gene expression related to lipid metabolism in hepatopancreas and hemolymph indicated a significant interaction between dietary lipid levels and DM in the lipid metabolism of shrimp. The terms of detoxification-related genes (gst, sult, cyp1a1) were upregulated in shrimp fed the high-dose DM. Additionally, the presence of DM in the diet severely harmed the hepatopancreas and intestinal histological morphology. DM in the diet increased the susceptibility of shrimp to pathogens and induced intestine microbiota dysbiosis, disrupting the balance of inter-species interactions. DM was not detected in the muscle and hepatopancreas of the shrimp after six weeks of exposure. In conclusion, the presence of DM in feed reduced the growth performance and antioxidant capacity of shrimp, damaging intestinal health. DM was rapidly metabolized by shrimp.

Comparison of hair steroid levels among Wistar rats exposed to different environmental enrichment settings

Background and Aim

Environmental enrichment (EE) is a pivotal tool for creating ideal housing conditions that allow animals to fully display their ethograms. At the micro-environmental level, they should elicit cognitive and social responses and increase physical activities. Hair steroids may be among the best biomarkers to evaluate the effects of prolonged exposure to different enrichments because they are non-invasive and provide information regarding a longer period. This study aimed to compare the hair steroid profiles, specifically corticosterone, cortisol, and dehydroepiandrosterone (DHEA), of Wistar rats exposed to two different EE settings.

Materials and Methods

Twenty (n = 20) outbred Wistar rats were enrolled in this study. First hair collection (T0) was performed 3 days before weaning (at 28 days of life), and then Wistar rats were randomly divided into two equal groups with a sex ratio of 1:1: standard EE group, provided with one rat tunnel, and extra EE group, provided with an additional tunnel hanging from the top of the cage. Environmental conditions were 20°C-24°C, 45%-65% relative humidity, and a 12:12 dark/light cycle, with water and pelleted diet ad libitum. The rats were housed in ventilated cages with poplar bedding and nesting material. Hair was sampled again after 3 months (T1). Steroids were quantified using radioimmunoassay or enzyme-linked immunosorbent assay after methanol extraction.

Results

Cortisol was not quantifiable, while corticosterone and DHEA were. After 3 months of exposure (T1), no differences were noted between the experimental groups. On data categorization per sex, females showed higher levels of all steroids than males. In males, the extra EE group had higher corticosterone levels.

Conclusion

This study showed that corticosterone and DHEA are quantifiable in rats' hair, yet bigger datasets are needed to better understand the physiological levels of these hormones in such a matrix. Different enrichment settings induced differences between and within sex.

Associations of Co-Exposure to Polycyclic Aromatic Hydrocarbons and Heavy Metals with Sex Steroid Hormones among Children Aged 6-19 Years

INTRODUCTION

Polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) are endocrine-disrupting chemicals (EDCs) that may have a combined effect on sex hormone levels in children. This study investigated the correlations between co-exposure to PAHs and HMs and levels of sex steroid hormones in children.

METHODS

We employed the data from the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2016, including 1,167 participants aged 6-19 years. Sex hormone indicators include testosterone (TT), estradiol (E2), sex hormone-binding globulin (SHBG), free androgen index (FAI), and the TT/E2 ratio. Weighted multivariate linear regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) were used to analyze the associations between co-exposure to PAHs and HMs and sex steroid hormone levels.

RESULTS

Co-exposure to PAHs and HMs was associated with a 16.2% reduction (95% CI [-0.321, -0.004]) in SHBG level among prepubertal males and a 16% reduction (95% CI [-0.30, -0.03]) in E2 level among pubertal males by the WQS regression, and cadmium (Cd) and mercury (Hg) contributed the highest weight, respectively. In the Bayesian kernel machine regression (BKMR) model, co-exposure to PAHs and HMs was positively associated with TT/E2 in pubertal males and negatively correlated with FAI in pubertal females, and 1-hydroxypyrene (1-PYR) and Cd were the most important components, respectively.

CONCLUSIONS

Co-exposure to PAHs and HMs was associated with sex hormone levels in children. These findings highlight the necessity for preventing the effects of these chemicals on sex hormones.

Cross-Sectional Examination of Thyroid Hormones and Environmental Exposure to Multiclass Pesticides in Women of Reproductive Age in China

BACKGROUND

Some pesticides have been shown to interfere with thyroid functions through changes in thyroid hormone (TH) levels. However, few human studies have explored associations between TH levels and environmental exposure to currently used pesticides, including neonicotinoids, phenylpyrazoles, phenoxy acids, and azoles. Moreover, such studies often measure biomarkers of exposure in urine or blood, and thus reveal only recent exposure. In contrast, hair has been demonstrated to be a suitable matrix for assessing chronic exposure to both persistent and nonpersistent organic pollutants.

OBJECTIVES

We investigated 54 biomarkers of pollutant exposure in relation to tetraiodothyronine (T4), 3,3',5-triiodothyronine (T3), 3,3',5'-triiodothyronine (rT3), and 3,3'-diiodothyronine (T2).

METHODS

In a cross-sectional study of 196 healthy Chinese women of reproductive age (25-45 years of age), concentrations of both pollutants and THs were analyzed in the first 12 cm (starting from the scalp) of the hair matrix, collected in 2016. Associations between pollutants and TH levels were explored using stability-enhanced least absolute shrinkage and selection operator (lasso) by regressing all exposures against each outcome of interest, adjusted for age, body mass index, and city.

RESULTS

Each TH was associated with the mixture of at least eight of the examined pesticides. We found associations of β -HCH, PCP, DMP, DETP, 3Me4NP, carbofuran, ClCF 3 CA , imidacloprid, 2,4-D, metolachlor, difenoconazole, and tebuconazole with THs. For example, a 2-standard deviation (SD) increase in log 10 -transformed hair DMP concentration was associated with lower hair T4 concentration [- 15.0 % (95% CI: - 26.1 , - 2.21 % )] and higher hair T3 concentration [8.16% (95% CI: 1.73, 15.0%)] in the adjusted unpenalized regression models. We also found associations of some pesticides with T3/T4, rT3/T4, and rT3/T3 molar ratios, including PCP, DMP, 2,4-D, metolachlor, difenoconazole, and tebuconazole.

DISCUSSION

Our results suggest that exposure to the low levels of pesticides examined here may disrupt thyroid homeostasis in humans. Further studies are needed to confirm our results and to evaluate the long-term consequences of these subtle interferences. https://doi.org/10.1289/EHP14378.

Using bioactive compounds to mitigate the formation of typical chemical contaminants generated during the thermal processing of different food matrices

With rising consumer awareness of health and wellness, the demand for enhanced food safety is rapidly increasing. The generation of chemical contaminants during the thermal processing of food materials, including polycyclic aromatic hydrocarbons, heterocyclic aromatic amines, and acrylamide happens every day in every kitchen all around the world. Unlike extraneous chemical contaminants (e.g., pesticides, herbicides, and chemical fertilizers), these endogenic chemical contaminants occur during the cooking process and cannot be removed before consumption. Therefore, much effort has been invested in searching for ways to reduce such thermally induced chemical contaminants. Recently, the addition of bioactive compounds has been found to be effective and promising. However, no systematic review of this practical science has been made yet. This review aims to summarize the latest applications of bioactive compounds for the control of chemical contaminants during food thermal processing. The underlying generation mechanisms and the toxic effects of these chemical contaminants are discussed in depth to reveal how and why they are suppressed by the addition of certain bioactive ingredients. Examples of specific bioactive compounds, such as phenolic compounds and organic acids, as well as their application scenarios, are outlined. In the end, outlooks and expectations for future development are provided based on a comprehensive summary and reflection of references.

Hair-Derived Exposome Exploration of Cardiometabolic Health: Piloting a Bayesian Multitrait Variable Selection Approach

Cardiometabolic health is complex and characterized by an ensemble of correlated and/or co-occurring conditions including obesity, dyslipidemia, hypertension, and diabetes mellitus. It is affected by social, lifestyle, and environmental factors, which in-turn exhibit complex correlation patterns. To account for the complexity of (i) exposure profiles and (ii) health outcomes, we propose to use a multitrait Bayesian variable selection approach and identify a sparse set of exposures jointly explanatory of the complex cardiometabolic health status. Using data from a subset (N = 941 participants) of the nutrition, environment, and cardiovascular health (NESCAV) study, we evaluated the link between measurements of the cumulative exposure to (N = 33) pollutants derived from hair and cardiometabolic health as proxied by up to nine measured traits. Our multitrait analysis showed increased statistical power, compared to single-trait analyses, to detect subtle contributions of exposures to a set of clinical phenotypes, while providing parsimonious results with improved interpretability. We identified six exposures that were jointly explanatory of cardiometabolic health as modeled by six complementary traits, of which, we identified strong associations between hexachlorobenzene and trifluralin exposure and adverse cardiometabolic health, including traits of obesity, dyslipidemia, and hypertension. This supports the use of this type of approach for the joint modeling, in an exposome context, of correlated exposures in relation to complex and multifaceted outcomes.

Association between Environmental Exposure to Multiclass Organic Pollutants and Sex Steroid Hormone Levels in Women of Reproductive Age

Organic pollutant exposure may alter sex steroid hormone levels in both animals and humans, but studies on mixture effects have been lacking and mainly limited to persistent organic pollutants, with few hormones being investigated. Moreover, measurements from a single blood or urine sample may not be able to reflect long-term status. Using hair analysis, here, we evaluated the relationship between multiclass organic pollutants and sex steroid hormones in 196 healthy Chinese women aged 25-45 years. Associations with nine sex steroid hormones, including progesterone, androstenedione (AD), testosterone (T), estrone (E1), and 17β-estradiol (E2), and eight related hormone ratios were explored on 54 pollutants from polychlorinated biphenyl (PCB), pesticide, and bisphenol families using stability-based Lasso regression analysis. Our results showed that each hormone was associated with a mixture of at least 10 examined pollutants. In particular, hair E2 concentration was associated with 19 pollutants, including γ-hexachlorocyclohexane, propoxur, permethrin, fipronil, mecoprop, prochloraz, and carbendazim. There were also associations between pollutants and hormone ratios, with pentachlorophenol, dimethylthiophosphate, 3-phenoxybenzoic acid, and flusilazole being related to both E1/AD and E2/T ratios. Our results suggest that exposure to background levels of pesticides PCB180 and bisphenol S may affect sex steroid hormone homeostasis among women of reproductive age.

Association of exposure to polycyclic aromatic hydrocarbons with thyroid hormones in adolescents and adults, and the influence of the iodine status

Some studies of endocrine-disrupting polycyclic aromatic hydrocarbon (PAH) exposure and thyroid hormones (THs) are inconclusive. To assess the associations between PAHs and THs, and the influence of the iodine status on PAHs-THs, we employed 648 adolescents (12-19 years old) and 2691 adults from the National Health and Nutrition Examination Survey 2007-2008 and 2011-2012. PAH metabolites [1-hydroxynaphthalene (1-NAP), 2-NAP, 1-hydroxyphenanthrene (1-PHE), 2-PHE, 3-PHE, 2-hydroxyfluorene (2-FLU), 3-FLU, 9-FLU, and 1-hydroxypyrene (1-PYR)], THs [total and free thyroxine (TT4 and FT4), total and free triiodothyronine (TT3 and FT3), thyroid stimulating hormone (TSH), and thyroglobulin (Tg)], peripheral deiodinase activity (GD) and thyroid's secretory capacity (GT) were involved. Multiple linear regression and weighted quantile sum (WQS) regression models were used to assess PAH-TH associations and the interaction between PAHs and the iodine status. Stratification analyses were conducted based on sex, smoking and iodine status. For adolescents, in a multivariable-adjusted regression model (β; 95% CI), 1-PHE (4.08%; 1.01%, and 7.25%), 2-PHE (3.98%; 0.70%, and 7.25%) and 9-FLU (3.77%; 1.10%, 7.47%) were positively correlated with TT3; 3-PHE and 1-PYR interacted with the iodine status (P-int < 0.05); 9-FLU was positively correlated with GD in both sexes. Combined exposure to PAHs was positively associated with Tg (0.137; 0.030, and 0.243), and negatively correlated with TSH (-0.087; -0.166, and -0.008). For adults, 2-NAP was positively correlated with FT3 (0.90%; 0.20%, and 1.61%), FT4 (1.82%; 0.70%, and 2.94%), TT3 (1.31%; 0.10%, and 2.63%), TT4 (2.12%; 0.90%, and 3.36%) and GT (2.22%; 1.01%, and 3.46%), but negatively correlated with TSH (-4.97%; -8.33%, and -1.49%); 1-NAP interacted with the iodine status (P-int < 0.05); 1-PHE was inversely correlated with TT3 in males; 2-PHE was positively correlated with TT3 in females. Combined exposure to PAHs was positively associated with FT3 (0.008; 0.001, and 0.014). Combined exposure to PAHs was positively associated with FT3, TT3 and GD, and negatively correlated with FT4, TT4 and GT in non-smoking adults; but positively associated with Tg (β = 0.140; 95% CI: 0.042, 0.237) in smoking adults. Our results indicated that combined and individual PAH exposure might be related to THs, and the iodine status had an influence on PAH-TH associations. These associations were not identical between adolescents and adults, and there were sex and smoking status differences.

Association of polycyclic aromatic hydrocarbon internal exposure and urinary iodine concentration with thyroid volume in children

Thyroid volume was proposed as a factor for malignancy in evaluating thyroid nodules. Previous studies have demonstrated the endocrine disrupting effect of polycyclic aromatic hydrocarbons (PAHs), but studies on the association between internal exposure of PAHs and thyroid volume are still scarce. In this work, we evaluated the association of polycyclic aromatic hydrocarbon internal exposure and urinary iodine concentration with thyroid volume in 590 school-age children without thyroid disease in Guangzhou, China. Urinary hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs), urinary iodine concentrations, and thyroid volumes were measured. The mean concentrations of urinary iodine and ΣOH-PAHs were 271.1 μg/L and 3.27 μg/L, respectively, and the mean thyroid volume was 2.4 mL. The associations of urinary iodine and OH-PAH concentrations with thyroid volume were investigated by multivariable linear regression and the Bayesian kernel machine regression models. Urinary ΣOH-PAHs were observed to be significantly positively associated with thyroid volume in multivariable linear regression models. The increase in each unit in the log-transformed concentration of ΣOH-PAHs caused 3.88% change in thyroid volume. The Bayesian kernel machine regression model demonstrated a positive joint effect of increased urinary ΣOH-PAHs on thyroid volume. Moreover, urinary ΣOH-PAHs were statistically significant linked to urinary iodine, and iodine mediated the relationship between urinary OH-PAHs and thyroid volume with the mediated proportions of 15.2.