Exposure to indoor pesticides during pregnancy in a multiethnic, urban cohort

Neonicotinoid Pesticides Affect Developing Neurons in Experimental Mouse Models and in Human Induced Pluripotent Stem Cell (iPSC)-Derived Neural Cultures and Organoids

Neonicotinoids are synthetic, nicotine-derived insecticides used worldwide to protect crops and domestic animals from pest insects. The reported evidence shows that they are also able to interact with mammalian nicotine receptors (nAChRs), triggering detrimental responses in cultured neurons. Exposure to high neonicotinoid levels during the fetal period induces neurotoxicity in animal models. Considering the persistent exposure to these insecticides and the key role of nAChRs in brain development, their potential neurotoxicity on mammal central nervous system (CNS) needs further investigations. We studied here the neurodevelopmental effects of different generations of neonicotinoids on CNS cells in mouse fetal brain and primary cultures and in neuronal cells and organoids obtained from human induced pluripotent stem cells (iPSC). Neonicotinoids significantly affect neuron viability, with imidacloprid (IMI) inducing relevant alterations in synaptic protein expression, neurofilament structures, and microglia activation in vitro, and in the brain of prenatally exposed mouse fetuses. IMI induces neurotoxic effects also on developing human iPSC-derived neurons and cortical organoids. Collectively, the current findings show that neonicotinoids might induce impairment during neuro/immune-development in mouse and human CNS cells and provide new insights in the characterization of risk for the exposure to this class of pesticides.

[Disruptors of thyroid hormones: Which consequences for human health and environment?]

Endocrine disruptors (EDs) of chemical origin are the subject of numerous studies, some of which have led to measures aimed at limiting their use and their impact on the environment and human health. Dozens of hormones have been described and are common to all vertebrates (some chemically related messengers have also been identified in invertebrates), with variable roles that are not always known. The effects of endocrine disruptors therefore potentially concern all animal species via all endocrine axes. These effects are added to the other parameters of the exposome, leading to strong, multiple and complex adaptive pressures. The effects of EDs on reproductive and thyroid pathways have been among the most extensively studied over the last 30 years, in a large number of species. The study of the effects of EDs on thyroid pathways and brain development goes hand in hand with increasing knowledge of 1) the different roles of thyroid hormones at cellular or tissue level (particularly developing brain tissue) in many species, 2) other hormonal pathways and 3) epigenetic interactions. If we want to understand how EDs affect living organisms, we need to integrate results from complementary scientific fields within an integrated, multi-model approach (the so-called translational approach). In the present review article, we aim at reporting recent discoveries and discuss prospects for action in the fields of medicine and research. We also want to highlight the need for an integrated, multi-disciplinary approach to studying impacts and taking appropriate action.

Association between maternal use of spray formulations and offspring urological anomalies: The Japan Environment and Children's Study

OBJECTIVE

Concerns exist regarding the effects of maternal inhalation of household products on fetal health. This study aimed to clarify the impact of maternal exposure to household products, including spray formulations, on urological anomalies in offspring up to the age of 1 year.

METHODS

This study included data from 84 237 children from the Japan Environment and Children's Study, an ongoing nationwide cohort study. Using maternal self-report questionnaires, information on the use of organic solvents, waterproof sprays, insect-repellent sprays, insecticide sprays, and herbicides from implantation until the second or third trimester of pregnancy and data on urological anomalies were collected 1 year after delivery.

RESULTS

Urological anomalies occurred in 799 infants. Multivariate logistic regression analysis adjusted for maternal age, pregnancy body mass index, gestational diabetes, pre-existing maternal kidney disease, and preterm birth revealed no association between maternal exposure to organic solvents and the prevalence of offspring urological anomalies. Nevertheless, we observed significant associations between waterproof spray use during pregnancy and urological anomalies in boys (odds ratio [OR]: 1.28, 95% confidence interval [CI]: 1.03-1.59) and between the use of insecticide spray during pregnancy and urological anomalies in girls (OR: 1.48, 95% CI: 0.98-2.22). Sub-analysis revealed significant associations between waterproof spray use during pregnancy and vesicoureteral reflux in boys (OR: 2.14, 95% CI: 1.02-4.49) and between the use of insecticide spray during pregnancy and hydronephrosis in girls (OR: 2.23, 95% CI: 1.11-4.47).

CONCLUSION

Spray formulation use during pregnancy might increase the risk of urological anomalies in the offspring.

High-Dose Deltamethrin Induces Developmental Toxicity in Caenorhabditis elegans via IRE-1

Deltamethrin (DM), a Type II pyrethroid, is widely used worldwide in agriculture, household applications, and medicine. Recent studies have shown that DM exerts a variety of toxic effects on organs such as the kidney, heart muscle, and nerves in animals. However, little is known about the effects of high-dose DM on growth and development, and the mechanism of toxicity remains unclear. Using the Caenorhabditis elegans model, we found that high-dose DM caused a delay in nematode development. Our results showed that high-dose DM reduced the activation of the endoplasmic reticulum unfolded protein response (UPRER). Further studies revealed that high-dose DM-induced developmental toxicity and reduced capacity for UPRER activation were associated with the IRE-1/XBP-1 pathway. Our results provide new evidence for the developmental toxicity of DM and new insights into the mechanism of DM toxicity.

Gene expression profiling of nasal inflammation induced by diesel particles using an in vivo system

Korean diesel particulate matter 20 (KDP20) is a pollutant comprising a complex mixture of carbon and chemical irritants. Although particulate matter and nasal inflammation are strongly associated, the underlying molecular mechanism based on systematic transcriptome analysis remains unknown. In this study, genome-wide gene expression profiles of mouse nasal tissues were determined following exposure to KDP20 for 5 and 10 days and compared with those of the control (n = 4/group). We identified 758 significant differentially expressed genes (DEGs) and classified them as 5-day-specific, 10-day-specific, and common among groups based on their expression patterns. The terms "regulation of alpha-beta T cell differentiation," "macrophage differentiation," and "cell adhesion mediated by integrin" were significantly enriched in each group. Receiver operating characteristic analysis revealed six genes as potential predictive biomarkers. The differential expression of these six genes was validated using quantitative RT-PCR (n = 3/group). Furthermore, a possible mechanism for nasal inflammation was suggested through the binding analysis between metal ions and genes. The genes identified in this study may play important roles in regulating the mechanism of nasal inflammation induced by diesel particles, especially immune cell regulation, and may function as markers for diesel particle-induced nasal inflammation.

Variability, determinants, and associations with oxidative stress biomarkers of pentachlorophenol among Chinese pregnant women: A longitudinal study

Pentachlorophenol (PCP) is ubiquitous and moderately persistent in the environment, and it is an identified human carcinogen. Previous animal experiments indicate that toxic mechanisms of PCP include oxidative stress. However, no epidemiological study has reported the association between PCP exposure and oxidative stress; such association in pregnant women, a vulnerable population, is of particular interest. This study aimed to characterize PCP concentrations in 2304 urine samples from 768 pregnant women, explore its determinants, and evaluate the associations between PCP exposure and three oxidative stress biomarkers across three trimesters. The median concentrations of PCP (100% detected) in the first, second, and third trimester were 0.61, 0.59, and 0.48 ng/mL, respectively, with a significant decrease trend. The intraclass correlation coefficient of specific gravity (SG)-adjusted PCP was 0.26, indicating high variability for PCP across the three trimesters. PCP concentrations were significantly higher in older, pre-pregnancy overweight, multiparous, high-income, and employed women during pregnancy. Urinary PCP was markedly lower in samples collected during spring compared to other seasons. Linear mixed effect models for repeated measures revealed that ln-transformed SG-adjusted PCP was significantly associated with increased 8-hydroxy-2'-deoxyguanosine (8-OHdG; percent change [%Δ] caused by each interquartile range increase of PCP: 46.2, 95% confidence interval [CI]: 40.2, 52.5) and 8-hydroxyguanosine (8-OHG;%Δ [95% CI]: 44.8 [40.1, 49.8]), but the positive association with 4-hydroxy2-nonenal-mercapturic acid (HNE-MA) was not significant. PCP was also positively associated with increased 8-OHdG and 8-OHG in each trimester using general linear models, and its associations with HNE-MA were only significant at T1 (%Δ [95% CI]: 19.1 [1.05, 40.3]) and T2 (%Δ [95% CI]: 12.6 [0.32, 26.3]). Our findings provide valuable information about PCP exposure characteristics during pregnancy and the potential effects of PCP exposure on oxidative stress in pregnant women.

Determination of potential toxicodynamic differences of pyrethroid insecticides on native voltage-sensitive sodium channels in juvenile versus adult rat brain

Microtransplantation of neurolemma tissue fragments from mammalian brain into the plasma membrane of Xenopus laevis oocytes is a tool to examine the endogenous structure and function of various ion channels and receptors associated with the central nervous system. Microtransplanted neurolemma can originate from a variety of sources, contain ion channels and receptors in their native configuration, and are applicable to examine diseases associated with different channelopathies. Here, we examined potential age-related differences in voltage-sensitive sodium channel (VSSC) expression and concentration-dependent responses to pyrethroids following the microtransplantation of juvenile or adult rat brain tissue (neurolemma) into X. laevis oocytes. Using automated western blotting, adult neurolemma exhibited a 2.5-fold higher level of expression of VSSCs compared with juvenile neurolemma. The predominant isoform expressed in both tissues was Na_v1.2. However, adult neurolemma expressed 2.8-fold more Na_v1.2 than juvenile and expressed Na_v1.6 at a significantly higher level (2.2-fold). Microtransplanted neurolemma elicited ion currents across the plasma membrane of oocytes following membrane depolarization using two electrode voltage clamp electrophysiology. A portion of this current was sensitive to tetrodotoxin (TTX) and this TTX-sensitive current was abolished when external sodium ion was replaced by choline ion, functionally demonstrating the presence of native VSSC. Increasing concentrations of permethrin or deltamethrin exhibited concentration-dependent increases in inward TTX-sensitive current in the presence of niflumic acid from both adult and juvenile tissues following a pulsed depolarization of the oocyte plasma membrane. Concentration-dependent response curves illustrate that VSSCs associated with juvenile neurolemma were up to 2.5-fold more sensitive to deltamethrin than VSSCs in adult neurolemma. In contrast, VSSCs from juvenile neurolemma were less sensitive to permethrin than adult VSSCs at lower concentrations (0.6-0.8-fold) but were more sensitive at higher concentrations (up to 2.4-fold). Nonetheless, because the expected concentrations in human brains following realistic exposure levels are approximately 21- (deltamethrin) to 333- (permethrin) times below the threshold concentration for response in rat neurolemma-injected oocytes, age-related differences, if any, are not likely to be toxicologically relevant.

A systematic review of human biomonitoring studies of 3-phenoxybenzoic acid, a urinary biomarker pyrethroid insecticide exposure, 1997 to 2019

Pyrethroid insecticides are used, for example, in agriculture, indoor environments, and mosquito control programs, resulting in human exposure. Urinary 3-phenoxybenzoic acid (3-PBA) is a nonspecific biomarker for exposure to many pyrethroids. This systematic review identified human biomonitoring studies with 3-PBA that characterize environmental pyrethroid exposures in children and adolescents, pregnant women, and adults or occupational pyrethroid exposures relative to the National Health and Nutrition Examination Survey (NHANES) populations in the United States (US). PubMed, Embase, and SciFinder were searched for "3-phenoxybenzoic acid ", CAS No. 3739-38-6, and urine or urinary or urine level. Duplicate studies and studies meeting the exclusion criteria were removed from the search results based on predetermined exclusion criteria. This screening process identified 57 papers. Twenty-one, thirteen, twenty-two, and eleven manuscripts reported urinary 3-PBA levels in children, pregnant women, environmentally exposed adults, and occupationally exposed adults, respectively. Median 3-PBA levels ranged from 0.2 to 4.7 μg/g creatinine in children (1999-2016), 0.23-1.55 μg/g creatinine in pregnant women (1997-2014), and 0.11-3.34 μg/g creatinine in environmentally exposed adults (1999-2017). 3-PBA levels in occupationally exposed adults were significantly higher than in environmentally exposed populations, ranging from 0.43 to 14 μg/g creatinine (2004-2017). 3-PBA levels in children and adults from the general North American population increased significantly with the sampling year. A decrease in 3-PBA levels was noted in the adult cohorts from PR China and Japan. 3-PBA levels in most studies appeared to be comparable to levels in the NHANES populations; however, some smaller studies had high pyrethroid exposures. Factors contributing to higher 3-PBA levels in the general population included primarily dietary exposures and residential and agricultural pyrethroid applications. These findings demonstrate that pyrethroid exposures are near-ubiquitous worldwide and, in some regions, appear to increase over time. Thus, exposures to pyrethroid insecticides represent a continuing public health concern.

Characterization of Urinary Pesticide Metabolite Concentrations of Pregnant Women in Suriname

Prenatal exposure to pesticides and the association with adverse health outcomes have been examined in several studies. However, the characterization of pesticide exposure among Surinamese women during pregnancy has not been assessed. As part of the Caribbean Consortium of Research in Environmental and Occupational Health research program, 214 urine samples were collected from pregnant women living in three regions in Suriname with different agricultural practices: capital Paramaribo, the rice producing district Nickerie, and the tropical rainforest, the Interior. We used isotope dilution tandem mass spectrometry to quantify urinary concentrations of biomarkers of three pesticide classes, including phenoxy acid herbicides and organophosphate and pyrethroid insecticides, all of which are commonly used in agricultural and residential settings in Suriname. We observed that participants residing in Nickerie had the highest urinary metabolite concentrations of 2,4-dichlorophenoxyacetic acid and pyrethroids compared to those from Paramaribo or the Interior. Paramaribo had the highest concentrations of organophosphate metabolites, specifically dialkyl phosphate metabolites. Para-nitrophenol was detected in samples from Paramaribo and the Interior. Samples from Nickerie had higher median urinary pesticide concentrations of 2,4-dichlorophenoxyacetic acid (1.06 μg/L), and the following metabolites, 3,5,6-trichloro-2-pyridinol (1.26 μg/L), 2-isopropyl-4-methyl-6-hydroxypyrimidine (0.60 μg/L), and 3-phenoxybenzoic acid (1.34 μg/L), possibly due to residential use and heavy rice production.

Pentachlorophenol exposure in early pregnancy and gestational diabetes mellitus: A nested case-control study

Pentachlorophenol (PCP) is an endocrine-disrupting chemical that is ubiquitously found in the environment. Few studies have reported PCP exposure in pregnant women and its association with gestational diabetes mellitus (GDM). This nested case-control study aimed to determine the concentration of urinary PCP in early pregnancy and explore the association between PCP exposure and GDM risk. This study included 293 GDM cases and 586 non-GDM controls matched by fetal sex and maternal age from a birth cohort in Wuhan, China. PCP concentrations in spot urine samples collected between 8 and 16 weeks of gestation were measured by ultra-performance liquid chromatography-tandem mass spectrometry. Conditional logistic regression was used to assess the association between PCP exposure and the odds ratio of GDM. The median concentrations of specific gravity-adjusted PCP in controls and cases were 0.70 and 0.80 ng/mL, respectively, with no significant differences (P > 0.05). The multivariate-adjusted odds ratios (ORs) (95% confidence intervals) for GDM across quartiles of urinary PCP were 1 (reference), 1.63 (1.06-2.50), 1.70 (1.11-2.61), and 1.35 (0.87-2.08), respectively, showing a potential "inverted-U" shaped association. In addition, PCP levels and maternal age or fetal sex had significant interactions with GDM risk (both P for interaction < 0.05). Among older women and those carrying female fetuses, the ORs of GDM risk were higher. This study suggests that pregnant women in central China are widely exposed to PCP, and this is the first time to report that PCP exposure may increase the risk of GDM (with potential effect modifications by maternal age and fetal sex). The association observed is in agreement with PCP's "inverted-U" anti-estrogenic effect in vivo; thus, such an effect in humans at environmentally relevant doses should be studied further.

Household pesticide exposures and infant gross motor development in the MADRES cohort

BACKGROUND

The development of motor skills in infancy is a vital neurodevelopmental milestone. Although previous studies have explored the neurotoxic effects of agricultural pesticides on infants' motor development, limited research has examined early postnatal household pesticide use on infants' motor development, particularly among urban communities.

OBJECTIVE

This study examined the association between early postnatal household pesticide use and infants' gross and fine motor development at 6 months of age.

METHODS

Questionnaires were administered via telephone to 296 mother-infant dyads in the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) pregnancy cohort. Early life household pesticide use was assessed via questionnaire administered when infants turned 3 months old and gross and fine motor development was assessed by the Ages and Stages Questionnaire (ASQ-3) at 6 months old. Infant gross motor scores were reverse coded so that higher scores indicated lower gross motor performance. Negative binomial regressions were performed to assess the relationship between household pesticide use and infant gross motor development.

RESULTS

Infants were predominantly Hispanic (78.7%) and full term (gestational age at birth: 39.0 ± 1.9 weeks), with 22.3% of maternal participants reporting household use of rodent and insect pesticides. Adjusting for recruitment site, maternal age, ethnicity, household income, education, infant corrected age, infant sex, and home type, infants with maternal-reported household use of rodent and insect pesticides had 1.30 times higher expected gross motor scores (95% confiidence interval 1.05, 1.61) than infants with no reported use of household pesticides, with higher scores indicating reduced gross motor performance.

CONCLUSIONS

Our results suggest household use of rodent and insect pesticides may harm infants' gross motor development in early childhood. Future research should evaluate the impact of specific household chemicals in infant biospecimens and their associations with infant motor development to confirm these findings.

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.

Concentrations of urinary biomarkers and predictors of exposure to pyrethroid insecticides in young, Polish, urban-dwelling men

Pyrethroid insecticides are a class of pesticides with multiple agricultural and residential applications. However, widespread use of these chemicals may pose a threat to human health. Biomarkers of pyrethroid exposure are frequently detected in populations around the world, but some groups may be underrepresented. Moreover, there is an ongoing debate on factors contributing to pyrethroid burden in humans. To address these problems, we measured urinary biomarkers of pyrethroid exposure in urine samples from 306 young men living in urban area of Łódź, Poland, and gathered questionnaire data to identify predictors of exposure. Limit of detection (LOD) of gas chromatography-mass spectrometry (GC-MS) method was 0.1 ng/mL for all quantified pyrethroid metabolites, namely cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (cis-DCCA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (trans-DCCA), cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid (cis-DBCA), and 3-phenoxybenzoic acid (3-PBA). Detection rate ranged from 32% (cis-DBCA) to 76% (trans-DCCA). Concentrations of urinary biomarkers in studied sample were in lower range of these observed in similar studies, with unadjusted geometric means (GMs) of most prevalent biomarkers, trans-DCCA and 3-PBA, equal to 0.268 and 0.228 ng/mL, respectively. As for questionnaire data, the statistical analysis revealed that non-dietary factors, especially dog ownership and pesticide use on household pets, contribute significantly to urinary trans-DCCA and 3-PBA concentrations (p ≤ 0.009). Moreover, a few dietary sources of exposure were identified, such as seeds and nuts consumption for 3-PBA (p < 0.001) and vegetable juice intake for trans-DCCA (p = 0.015). Multivariate analyses further highlighted the importance of non-dietary factors in pyrethroid exposure. Compared to other works, our results confirm widespread exposure to pyrethroids observed in other studies and stress the role of residential pyrethroid use in pyrethroid burden in humans.

Effects of pyrethroids on brain development and behavior: Deltamethrin

Deltamethrin (DLM) is a Type II pyrethroid pesticide widely used in agriculture, homes, public spaces, and medicine. Epidemiological studies report that increased pyrethroid exposure during development is associated with neurobehavioral disorders. This raises concern about the safety of these chemicals for children. Few animal studies have explored the long-term effects of developmental exposure to DLM on the brain. Here we review the CNS effects of pyrethroids, with emphasis on DLM. Current data on behavioral and cognitive effects after developmental exposure are emphasized. Although, the acute mechanisms of action of DLM are known, how these translate to long-term effects is only beginning to be understood. But existing data clearly show there are lasting effects on locomotor activity, acoustic startle, learning and memory, apoptosis, and dopamine in mice and rats after early exposure. The most consistent neurochemical findings are reductions in the dopamine transporter and the dopamine D1 receptor. The data show that DLM is developmentally neurotoxic but more research on its mechanisms of long-term effects is needed.

The urban lead (Pb) burden in humans, animals and the natural environment

Centuries of human activities, particularly housing and transportation practices from the late 19th century through the 1980's, dispersed hundreds of millions of tons of lead into our urban areas. The urban lead burden is evident among humans, wild and domesticated animals, and plants. Animal lead exposures closely mirror and often exceed the lead exposure patterns of their human partners. Some examples: Pigeons in New York City neighborhoods mimicked the lead exposures of neighborhood children, with more contaminated areas associated with higher exposures in both species. Also, immediately following the lead in drinking water crisis in Flint MI in 2015, blood lead levels in pet dogs in Flint were 4 times higher than in surrounding towns. And combining lead's neurotoxicity with urban stress results in well-characterized aggressive behaviors across multiple species. Lead pollution is not distributed evenly across urban areas. Although average US pediatric lead exposures have declined by 90% since the 1970s, there remain well defined neighborhoods where children continue to have toxic lead exposures; animals are poisoned there, too. Those neighborhoods tend to have disproportionate commercial and industrial lead activity; a history of dense traffic; older and deteriorating housing; past and operating landfills, dumps and hazardous waste sites; and often lead contaminated drinking water. The population there tends to be low income and minority. Urban wild and domesticated animals bear that same lead burden. Soil, buildings, dust and even trees constitute huge lead repositories throughout urban areas. Until and unless we begin to address the lead repositories in our cities, the urban lead burden will continue to impose enormous costs distributed disproportionately across the domains of the natural environment. Evidence-based research has shown the efficacy and cost-effectiveness of some US public policies to prevent or reduce these exposures. We end with a series of recommendations to manage lead-safe urban environments.

Predictors of Urinary Pyrethroid and Organophosphate Compound Concentrations among Healthy Pregnant Women in New York

Our study aimed to investigate dietary and non-dietary predictors of exposure to pyrethroids, organophosphates pesticides and 2,4-D herbicide in two cohorts of pregnant women in New York City: 153 women from the Thyroid Disruption and Infant Development (TDID) cohort and 121 from the Sibling/Hermanos Cohort(S/H). Baseline data on predictors were collected from the women at time of recruitment. We used three different modeling strategies to address missing data due to biomarker values below the limit of detection (<LOD): (1) logistic regression models with biomarkers categorized as (<median, ≥median); (2) linear regression models, imputing the <LOD values with (LOD/√2); (3) regression models, considering <LOD values as left-censored. Generally, all three models identified similar predictors of exposure. We found that ethnicity, higher income and education predicted higher concentrations of most of the biomarkers in both cohorts. Mothers who consumed processed meat in the TDID cohort, and broiled, barbequed food or burgers in the S/H cohort, tended to have lower concentrations of organophosphates and 2,4-D. The choice of modeling led to a few different predictors identified, and the selection of modeling strategy should be based on the study question.

Organophosphate toxicity: updates of malathion potential toxic effects in mammals and potential treatments

Organophosphorus insecticides toxicity is still considered a major global health problem. Malathion is one of the most commonly used organophosphates nowadays, as being considered to possess relatively low toxicity compared with other organophosphates. However, widespread use may lead to excessive exposure from multiple sources. Mechanisms of MAL toxicity include inhibition of acetylcholinesterase enzyme, change of oxidants/antioxidants balance, DNA damage, and facilitation of apoptotic cell damage. Exposure to malathion has been associated with different toxicities that nearly affect every single organ in our bodies, with CNS toxicity being the most well documented. Malathion toxic effects on liver, kidney, testis, ovaries, lung, pancreas, and blood were also reported. Moreover, malathion was considered as a genotoxic and carcinogenic chemical compound. Evidence exists for adverse effects associated with prenatal and postnatal exposure in both animals and humans. This review summarizes the toxic data available about malathion in mammals and discusses new potential therapeutic modalities, with the aim to highlight the importance of increasing awareness about its potential risk and reevaluation of the allowed daily exposure level.

Phenotypic and transcriptomic changes in zebrafish (Danio rerio) embryos/larvae following cypermethrin exposure

Cypermethrin is one of the widely used type-II pyrethroid and the indiscriminate use of this pesticide leads to life threatening effects and in particular showed developmental effects in sensitive populations such as children and pregnant woman. However, the molecular mechanisms underlying cypermethrin-induced development toxicity is not well defined. To address this gap, the present study was designed to investigate the phenotypic and transcriptomic (next generation RNA-Seq method) impact of cypermethrin in zebrafish embryos as a model system. Zebrafish embryos at two time points, 24 h postfertilization (hpf) and 48 hpf were exposed to cypermethrin at a concentration of 10 μg/L. Respective control groups were maintained. Cypermethrin induced both phenotypic and transcriptomic changes in zebrafish embryos at 48 hpf. The phenotypic anomalies such as delayed hatching rate, increased heartbeat rate and deformed axial spinal curvature in cypermethrin exposed zebrafish embryos at 48 hpf as compared to its respective controls. Transcriptomic analysis indicated that cypermethrin exposure altered genes associated with visual/eye development and gene functional profiling also revealed that cypermethrin stress over a period of 48 h disrupts phototransduction pathway in zebrafish embryos. Interestingly, cypermethrin exposure resulted in up regulation of only one gene, tnnt3b, fast muscle troponin isoform 3T in 24 hpf embryos as compared to its respective controls. The present model system, cypermethrin exposed zebrafish embryos elaborates the toxic consequences of cypermethrin exposure during developmental stages, especially in fishes. The present findings paves a way to understand the visual impairment in sensitive populations such as children exposed to cypermethrin during their embryonic period and further research is warranted.

Deltamethrin induces liver fibrosis in quails via activation of the TGF-β1/Smad signaling pathway

Deltamethrin (DLM) is an important member of the pyrethroid pesticide family, and its widespread use has led to serious environmental and health problems. Exposure to DLM causes pathological changes in the liver of animals and humans and can lead to liver fibrosis. However, the mechanism of DLM-induced liver fibrosis remains unclear. Therefore, to address its potential molecular mechanisms, we used both in vivo and in vitro methods. Quails were treated in vivo by intragastric administration of different concentrations of DLM (0, 15, 30, or 45 mg kg^-1), and the chicken liver cancer cell line LMH was treated in vitro with various doses of DLM (0, 50, 200, or 800 μg mL^-1). We found that DLM treatment in vivo induced liver fibrosis in a dose-dependent manner through the promotion of oxidative stress, activation of transforming growth factor-β1 (TGF-β1) and phosphorylation of Smad2/3. Treatment of LMH cells with different concentrations of DLM similarly induced oxidative stress and also decreased cell viability. Collectively, our study demonstrates that DLM-induced liver fibrosis in quails occurs via activation of the TGF-β1/Smad signaling pathway.

Implantation and pregnancy outcome of Sprague-Dawley rats exposed to pirimiphos-methyl

OBJECTIVE

This study was designed to investigate the effect of sublethal doses (10, 60, and 120 mg/kg of pirimiphos-methyl on implantation and pregnancy in female Sprague-Dawley rats. Pirimiphos-methyl is a pesticide widely used worldwide, especially in Africa to protect food against pests and has gained widespread acceptance.

METHODS

Pregnant Sprague-Dawley rats used for this study had access to food and water ad libitum and were divided into a control group and three experimental groups based on dose of chemical given. The pregnant rats were given pirimiphos-methyl orally on days 1-5, 1-7, 7-18th day of gestation and from day 1 to term. Implantation studies were carried out on days 6 and 8 of pregnancy, while the fetal parameters were ascertained on day 19 of pregnancy and at term. Serum levels of progesterone and estradiol were measured on days 6, 8 and 19 of pregnancy.

RESULTS

Sublethal administration of pirimiphos-methyl showed decreased number of implantation sites on days 6 and 8, fetal weight, crown-to-rump length, length of umbilical cord and placenta weight (day 19), birth weight, litter size and total number (at term) in rats administered with pirimiphos-methyl when compared with control.

CONCLUSION

Administration of pirimiphos-methyl resulted in a reduced implantation rate due to decreased uterine receptivity caused by an imbalance in the level of estradiol and progesterone and impaired reproductive outcome during pregnancy.

Toxicologic evidence of developmental neurotoxicity of Type II pyrethroids cyfluthrin and alpha-cypermethrin in SH-SY5Y cells

We attempted to identify cellular mechanisms as an approach to screen chemicals for the potential to cause developmental neurotoxicity. We examine, in SH-SY5Y cells, whether apoptosis and oxidative stress via reactive oxygen species (ROS) generation, caspase 3/7 activation, gene expression (Bax, Bcl-2, Casp-3, BNIP3, p53 and Nrf2) alterations and necrosis by release of cytosolic adenylate kinase (AK), underlie direct effects of the pyrethroids cyfluthrin and alpha-cypermethrin. We also determined transcriptional alterations of genes (TUBB3, NEFL, NEFH, GAP43, CAMK2A, CAMK2B, WNT3A, WNT5A, WNT7A, SYN1 and PIK3C3) linked to neuronal development and maturation. Our results indicate that cyfluthrin and alpha-cypermethrin have the ability to elicit concentration-dependent increases in AK release, cellular ROS production, caspase 3/7 activity and gene expression of apoptosis and oxidative stress mediators. Both pyrethroids caused changes in mRNA expression of key target genes linked to neuronal development. These changes might reflect in a subsequent neuronal dysfunction. Our study shows that SH-SY5Y cell line is a valuable in vitro model for predicting development neurotoxicity. Our research provides evidence that cyfluthrin and alpha-cypermethrin have the potential to act as developmental neurotoxic compounds. Additional information is needed to improve the utility of this in vitro model and/or better understand its predictive capability.

Association of prenatal pesticide exposures with adverse pregnancy outcomes and stunting in rural Bangladesh

BACKGROUND

Pesticide exposure during pregnancy is thought to adversely affect fetal growth, which in turn may impact child growth, but results have been inconsistent across studies and few have explored these effects in developing countries.

OBJECTIVES

To quantify urinary concentrations of pesticide biomarkers in early pregnancy (<16 weeks' gestation), and to estimate the association of these concentrations with preterm birth, low birth weight, small for gestational age, and stunting at ~1 and 2 years of age.

METHODS

Eight pesticide biomarkers were quantified in urine collected from 289 pregnant women (aged 18-40 years) participating in a birth cohort study in Bangladesh. Anthropometry measurements were conducted on the index child at birth and approximately 1 and 2 years of age. A directed acyclic graph was used to identify minimal sufficient adjustment sets. Log-binomial regression was used to estimate the relative risk (RR) with 95% confidence intervals (CI).

RESULTS

3,5,6-trichloro-2-pyridinol (TCPY), a metabolite of chlorpyrifos and chlorpyrifos methyl, and 4-nitrophenol, a metabolite of parathion and methyl parathion, were detected in nearly all women with geometric mean (95% CI) values of 3.17 (2.82-3.56) and 18.66 (17.03-20.46) µg/g creatinine, respectively. 3-phenoxybenzoic acid (3-PBA), a non-specific metabolite of several pyrethroids, and 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMPY), a diazinon metabolite, were detected in 19.8% and 16.1% of women, respectively. The remaining four pesticide biomarkers were detected in <10% of women. Women in the highest quartile of 4-nitrophenol were more than 3 times more likely to deliver preterm than women in the lowest quartile: unadjusted RR (95% CI), 3.57 (1.65, 7.73). Women in the highest quartile of 4-nitrophenol were also at increased risk of having a child born small for gestational age: RR (95% CI) adjusted for household income, maternal education, and maternal total energy and meat intake, 3.81 (1.10, 13.21). Women with detectable concentrations of IMPY were at increased risk of having a child born with low birth weight compared to women with non-detectable concentrations: adjusted RR (95% CI), 2.13 (1.12, 4.08). We observed no association between any of the pesticide biomarkers and stunting at 1 or 2 years of age.

DISCUSSION

Exposure to the insecticides parathion and diazinon during early pregnancy may increase the risk of adverse birth outcomes.

Evaluation of chlorpyrifos residue in breast milk and its metabolite in urine of mothers and their infants feeding exclusively by breast milk in north of Iran

BACKGROUND

The most common method of combating insects in low-income communities and developing countries, is the use of insecticides. The use of organophosphate insecticides is increasing due to their low prices and availability on the market. Chlorpyrifos is a medium-risk insecticide for human. The widespread use of organophosphorus insecticides, especially chlorpyrifos, in residential homes has undoubtedly created many health concerns. Babies have a high sensitivity to pesticides and environmental contaminants because of their evolutionary status. On the other hand, the main source of infants' exposure who are breast-fed exclusively to environmental pollutants is through breast milk and oral contact with objects that are covered with dust and particles.

METHODS

In this cross-sectional study, the concentration of chlorpyrifos in breast milk and its metabolite in urine samples of mothers and their under six months infants, feeding exclusively by breast milk in north of Iran have been investigated. The demographic data was collected through interviewing with selected mothers and completion of prepared data collecting forms. The data were statistically analyzed to investigate the relationships between exposure of mothers and their infants to chlorpyrifos.

RESULTS

The mean concentration of chlorpyrifos and its metabolite in mothers' urine and milk samples and infant's urines were 1.3 ± 0.6, 2.1 ± 1.4 and 1.4 ± 0.7 μg/L, respectively. Also, the mean concentration of chlorpyrifos in the dust on the house floors was73.4 ± 49 ng/g. There are good correlations between the mean values of chlorpyrifos concentrations and its metabolite in mother's milk and urine (r = 0.872, p = 0.001), and the mother's milk and infant's urine (r = 0.722, p = 0.001). Also, there was a significant correlation between the concentration of chlorpyrifos in floor dust and its metabolites in the infant's urine (r = 0.554, p = 0.001).

CONCLUSION

Our study suggests that the infants are the recipient of concentrated forms of chlorpyrifos residues through breast milk and house dust and it is quite well known that OP pesticides are toxic and have different kinds of adverse health effects. However, further research needs to be done to determine what these chemicals are doing to our children.

Determination of maternal and foetal distribution of cis- and trans-permethrin isomers and their metabolites in pregnant rats by liquid chromatography tandem mass spectrometry (LC-MS/MS)

We developed a method to quantify cis-permethrin and trans-permethrin and their metabolites in several biological matrices in pregnant rats and foetuses using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The objective was to quantify cis-permethrin and trans-permethrin in faeces, kidney, mammary gland, fat and placenta in mothers and in both maternal and foetal blood, brain and liver. The metabolites cis-3-(2,2-dichlorovinyl)-2,2-dimethyl-(1-cyclopropane) carboxylic acid (cis-DCCA), trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-(1-cyclopropane) carboxylic acid (trans-DCCA) and 3-phenoxybenzoic acid (3-PBA) were measured in blood, liver and urine. Sample preparation was performed by liquid-liquid extraction. A purification step was not carried out except for the more complex biological samples (fat, mammary glands and faeces). Validation parameters including specificity, linearity, matrix effect, limits of quantification (LOQs), accuracy and precision were evaluated. The recoveries of target compounds ranged from 47 to 136%. LOQs were in the range 4 to 80 ng/mL for permethrin isomers and 4 to 800 ng/mL for their respective metabolites. Intra- and inter-batch precision and accuracy in matrix were better than 15%. The validated method was applied in a preliminary toxicokinetic study in pregnant rats with oral dosing of 50 mg/kg permethrin. In pregnant rats, permethrin isomers and their metabolites were quantified in all requested matrices except maternal liver and blood for trans-permethrin and cis-DCCA respectively. In foetuses, cis- and trans-permethrin were also quantified, demonstrating that the method is suitable for the analysis of foetal distribution of permethrin in toxicokinetic studies.

Acute Exposure to Permethrin Modulates Behavioral Functions, Redox, and Bioenergetics Parameters and Induces DNA Damage and Cell Death in Larval Zebrafish

Permethrin (PM) is a synthetic pyrethroid insecticide widely used as domestic repellent. Damage effects to nontarget organisms have been reported, particularly in the early stages of development. Studies indicate redox unbalance as secondary PM effect. Therefore, our goal was to investigate the acute PM effects on larval zebrafish. Larvae (6 days postfertilization) were exposed to PM (25–600 μg/L) during 24 hours, and 50% lethal concentration was estimated. For subsequent assays, the sublethal PM concentrations of 25 and 50 μg/L were used. PM increased anxiety-like behaviors according to the Novel Tank and Light-Dark tests. At the molecular level, PM induced increased ROS, which may be related to the increased lipid peroxidation, DNA damage, and apoptosis detected in PM-exposed organisms. In parallel, upregulation of the antioxidant system was detected after PM exposure, with increased superoxide dismutase, glutathione S-transferase and glutathione reductase activities, and thiol levels. The increased of Nrf2 target genes and the activation of an electrophile response element-driven reporter Tg(EPRE:LUC-EGFP) suggest that the Nrf2 pathway can mediate a fast response to PM, leading to antioxidant amplification. By using high-resolution respirometry, we found that exposure to PM decreased the oxygen consumption in all respiratory stages, disrupting the oxidative phosphorylation and inhibiting the electron transfer system, leading to decrease in bioenergetics capacity. In addition, PM led to increases of residual oxygen consumption and changes in substrate control ratio. Glucose metabolism seems to be affected by PM, with increased lactate dehydrogenase and decreased citrate synthase activities. Taken together, our results demonstrated the adverse effects of acute sublethal PM concentrations during larval development in zebrafish, causing apparent mitochondrial dysfunction, indicating a potential mechanism to redox unbalance and oxidative stress, which may be linked to the detected cell death and alterations in normal behavior patterns caused by acute PM exposure.

Urinary metabolites of organophosphate and pyrethroid pesticides in children from an Italian cohort (PHIME, Trieste)

Urinary metabolites of organophosphate (OP) and pyrethroid (PYR) pesticides from seven years old children of a birth cohort study (n=199; PHIME cohort of Trieste, Italy) have been measured. Six OP and two PYR metabolites have been investigated, 2-diethylamino-6-methylpyrimidin-4-ol (DEAMPY, pirimiphos metabolite) was the one found at higher concentrations, median 3.4 ng/mL specific gravity adjusted (SG adjusted), followed by 4-nitrophenol (PNP, median 1.4 ng/mL SG adjusted) and 3,5,6-trichloro-2-pyridinol (TCPY, median 0.36 ng/mL SG adjusted), parathion and chlorpyriphos metabolites, respectively. TCPY concentrations were low in comparison to other distributions of OP metabolites in children from other studies. Accordingly, the PHIME cohort showed a distinct OP metabolite distribution with high concentrations of pirimiphos and parathion. Another specific characteristic of this cohort was the high concentration of 3-phenoxybenzoic acid (3-BPA, median 0.36 ng/mL SG adjusted), a general metabolite of PYR pesticides. Evaluation of anthropometric and socio-demographic characteristics of children and families only showed a positive association between family educational level and urinary concentrations of DEAMPY metabolite (p<0.05), which could reflect distinct dietary habits depending on the educational level. Estimated daily intakes were evaluated, all studied metabolites were found within safe levels.

Deltamethrin promotes adipogenesis via AMPKα and ER stress-mediated pathway in 3T3- L1 adipocytes and Caenorhabditis elegans

Previous research has shown that deltamethrin, a Type-II pyrethroid, increases fat accumulation in adipocytes and Caenorhabditis elegans. The underlying mechanisms on how deltamethrin promotes fat accumulation, however, are unknown. The aim of the current study was therefore to determine the possible mechanisms through which deltamethrin increases fat accumulation in mouse 3T3-L1 adipocytes and C. elegans. Deltamethrin (10 μM) significantly increased fat accumulation, and the expression of adipogenic regulators, such as CCAAT/enhancer-binding protein (C/EBPα) and fatty acid synthase (FAS). Deltamethrin significantly decreased the phosphorylation of AMP-activated kinase α (AMPKα), while it increased protein expression of endoplasmic reticulum (ER) stress markers in 3T3-L1 adipocytes and C. elegans. The activation of AMPK with 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) or the inhibition of ER stress with 4-phenylbutyrate (4-PBA) abolished the effects of deltamethrin on adipogenesis. Further study reveals that 4-PBA recovered the decreased AMPK phosphorylation induced by deltamethrin. These results suggest that deltamethrin promotes adipogenesis through an ER stress-AMPKα mediated pathway.

[Thyroid disruptors and their consequences on brain development and behavior]

An increase in the prevalence of many diseases affecting the nervous system in both children and adults has been reported. Some of these diseases are related to endocrine dysfunction, notably of the thyroid axis. Examples in children are attention deficit/hyperactivity disorders and Autism Spectrum Disorders, diagnosed but most often affecting the whole life, and multiple sclerosis or Alzheimer's disease in adults. It is becoming increasingly clear that embryonic exposure to thyroid hormone disruptors can lead to short- and long-term consequences, that often escape conventional neonatal diagnosis. Endocrine disruptors comprise a wide range of molecules, plasticizers, some pesticides, surfactants, flame-retardants, etc., many of which can interfere with thyroid hormone synthesis or their actions. We here report briefly the history of endocrine disruptors, their properties and the consequences on neuronal development of embryonic exposure to some of them.

Pyrethroid pesticide exposure and hematological cancer: epidemiological, biological and molecular evidence

Pyrethroid insecticides are commonly used worldwide. The chronic effects of these compounds are of concern given that epidemiological studies have suggested an association with hematological cancer, particularly in children. However, the biological evidence at molecular and cellular levels is limited. A review on the molecular and cellular effects of pyrethroids is helpful to guide the study of the biological plausibility of the association of pyrethroids with hematological cancer. We reviewed studies suggesting that pyrethroids are genotoxic, induce genetic rearrangements, alter gene expression and modify DNA. All of these biological modifications could potentially contribute to the carcinogenic process in hematopoietic cells.

A Neurodevelopmental Model of Combined Pyrethroid and Chronic Stress Exposure

Attention-deficit hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders of childhood and previous studies indicate the dopamine system plays a major role in ADHD pathogenesis. Two environmental exposures independently associated with dopaminergic dysfunction and ADHD risk include exposure to deltamethrin, a pyrethroid insecticide, and chronic stress. We hypothesized that combined neurodevelopmental exposure to both deltamethrin and corticosterone (CORT), the major stress hormone in rodents, would result in additive changes within the dopamine system. To study this, we developed a novel dual exposure paradigm and exposed pregnant C57BL/6 dams to 3 mg/kg deltamethrin through gestation and weaning, and their offspring to 25 μg/mL CORT dissolved in the drinking water through adulthood. Midbrain RNA expression as well as striatal and cortical protein expression of key dopaminergic components were investigated, in addition to ADHD-like behavioral tasks and electrochemical dopamine dynamics via fast-scan cyclic voltammetry. Given the well-described sexual dimorphism of ADHD, males and females were assessed separately. Males exposed to deltamethrin had significantly decreased midbrain Pitx3 expression, decreased cortical tyrosine hydroxylase (TH) expression, increased activity in the Y maze, and increased dopamine uptake rate in the dorsal striatum. These effects did not occur in males exposed to CORT only, or in males exposed to both deltamethrin and CORT, suggesting that CORT may attenuate these effects. Additionally, deltamethrin- and CORT-exposed females did not display these dopaminergic features, which indicates these changes are sex-specific. Our results show dopaminergic changes from the RNA through the functional level. Moreover, these data illustrate the importance of testing multiple environmental exposures together to better understand how combined exposures that occur in certain vulnerable populations could affect similar neurodevelopmental systems, as well as the importance of studying sex differences of these alterations.

The relationship of urinary 3-phenoxybenzoic acid concentrations in utero and during childhood with adiposity in 4-year-old children

BACKGROUND

Pyrethroid pesticides are reported to be the most commonly used residential insecticides worldwide. We aimed to investigate the relationship between prenatal and postnatal 3-phenoxybenzoic acid (3-PBA) concentrations, and growth and adiposity parameters in 4-year-old children.

METHOD

We obtained data from 578 children who participated in the prospective Environment and Development of Children (EDC) study at around 4 years of age (45-55 months) between August 2008 and July 2011. Anthropometric measurements were obtained at age 4 years. Prenatal and postnatal urinary 3-PBA concentration was measured in maternal urine samples at around 20 weeks of gestation, and in the 4-year-old children, respectively.

RESULT

The detection frequency of urinary 3-PBA (geometric mean concentration) was 98-99% (0.98 μg/g Cr) in maternal urine, and almost 99-100% (1.34 μg/g Cr) in 4-year-old children. Prenatal urinary3-PBA concentration was not associated with height, weight, or body mass index (BMI) z-scores at 4 years of age, regardless of sex. Postnatal urinary3-PBA concentration was not related to height z-scores, but was positively associated with weight z-scores with marginal significance among only girls (p = 0.058). Analyzed by sex, there was a significant relationship between postnatal urinary 3-PBA concentration and BMI z-scores (p = 0.015) among girls, after adjusting for covariates.

CONCLUSION

Childhood urinary 3-PBA concentration measured at 4 years of age was positively associated with BMI z-scores in 4-year-old girls, but prenatal urinary 3-PBA concentration at midterm pregnancy exhibited no association.

Determinants of Exposure to Pyrethroid Insecticides in the VHEMBE Cohort, South Africa

Exposure to pyrethroid insecticides has been linked to adverse health effects, and can originate from several sources, including indoor residual spraying (IRS) for malaria control, home pest control, food contamination, and occupational exposure. We aimed to explore the determinants of urinary pyrethroid metabolite concentrations in a rural population with high pesticide use. The Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) is a birth cohort of 752 mother-child pairs in Limpopo, South Africa. We measured pyrethroid metabolites in maternal urine and collected information on several factors possibly related to pesticide exposure, including IRS, home pesticide use, and maternal factors (e.g., dietary habits and body composition). We performed statistical analysis using both conventional bivariate regressions and Bayesian variable selection methods. Urinary pyrethroid metabolites are consistently associated with pesticide factors around homes, including pesticide application in yards and food stocks, and IRS in the home during pregnancy, while more distant factors such as village spraying are not. High fat intake is associated with higher metabolite concentrations, and women from homes drawing water from wells or springs had marginally higher levels. Home pesticide use is the most consistent correlate of pyrethroid metabolite concentrations, but IRS, dietary habits, and household water source may also be important exposure determinants.

Mechanisms of organophosphorus pesticide toxicity in the context of airway hyperreactivity and asthma

Numerous epidemiologic studies have identified an association between occupational exposures to organophosphorus pesticides (OPs) and asthma or asthmatic symptoms in adults. Emerging epidemiologic data suggest that environmentally relevant levels of OPs may also be linked to respiratory dysfunction in the general population and that in utero and/or early life exposures to environmental OPs may increase risk for childhood asthma. In support of a causal link between OPs and asthma, experimental evidence demonstrates that occupationally and environmentally relevant OP exposures induce bronchospasm and airway hyperreactivity in preclinical models. Mechanistic studies have identified blockade of autoinhibitory M2 muscarinic receptors on parasympathetic nerves that innervate airway smooth muscle as one mechanism by which OPs induce airway hyperreactivity, but significant questions remain regarding the mechanism(s) by which OPs cause neuronal M2 receptor dysfunction and, more generally, how OPs cause persistent asthma, especially after developmental exposures. The goals of this review are to 1) summarize current understanding of OPs in asthma; 2) discuss mechanisms of OP neurotoxicity and immunotoxicity that warrant consideration in the context of OP-induced airway hyperreactivity and asthma, specifically, inflammatory responses, oxidative stress, neural plasticity, and neurogenic inflammation; and 3) identify critical data gaps that need to be addressed in order to better protect adults and children against the harmful respiratory effects of low-level OP exposures.

Urinary levels of pyrethroid pesticides and determinants in pregnant French women from the Elfe cohort

Pyrethroids are insecticides which are widely used for agricultural and domestic purposes. The general population can be exposed to them. Given the suspected effects of pesticides on the development of the foetus, exposure to pyrethroids during pregnancy is a major public health concern. The objective of this paper is to describe the urinary levels of the following five pyrethroid metabolites and their associated determinants among pregnant French women in 2011 enrolled in the Elfe cohort (n = 1077): a) 3-phenoxy benzoic (3-PBA), b) 4‑fluoro‑3‑phenoxy benzoic acid (4-F-3-PBA), c) Cis‑3‑(2,2dibromovinyl)‑2,2‑dimethyl cyclopropane-carboxylic acid (Cis-DBCA); d) Cis‑3‑(2,2dichlorovinyl)‑2,2‑dimethyl cyclopropane-carboxylic acid (Cis-DCCA) and e) Trans-3‑(2,2dichlorovinyl)‑2,2‑dimethyl cyclopropane-carboxylic acid (Trans-DCCA). The distribution levels were estimated for each pyrethroid metabolite. Multivariable analyses helped determine the predictors of these levels. All metabolites except 4-F-3-PBA were detected in all the urine samples. The mean urinary concentration of the sum of the metabolites (3-PBA, Cis-DBCA, Cis-DCCA, Trans-DCCA) was 1.18 μg/L, with the highest concentrations observed for 3-PBA. A comparison of these levels with other studies showed that pregnant French women tend to be more exposed to pyrethroids than their American counterparts, less exposed than Chinese and Caribbean mothers, and have similar exposure to Japanese mothers. In our study, urinary levels of pyrethroid metabolites were positively related to smoking during pregnancy, consuming fish and alcohol, domestic pesticide use and living in the vicinity of crops during pregnancy. These findings highlight the importance of non-dietary pathways when evaluating exposure to pyrethroids.

Early Life Characteristics and Neurodevelopmental Phenotypes in the Mount Sinai Children's Environmental Health Center

Neurodevelopmental outcomes including behavior, executive functioning, and IQ exhibit complex correlational structures, although they are often treated as independent in etiologic studies. We performed a principal components analysis of the behavioral assessment system for children, the behavior rating inventory of executive functioning, and the Wechsler scales of intelligence in a prospective birth cohort, and estimated associations with early life characteristics. We identified seven factors: (1) impulsivity and externalizing, (2) executive functioning, (3) internalizing, (4) perceptual reasoning, (5) adaptability, (6) processing speed, and (7) verbal intelligence. Prenatal fish consumption, maternal education, preterm birth, and the home environment were important predictors of various neurodevelopmental factors. Although maternal smoking was associated with more adverse externalizing, executive functioning, and adaptive composite scores in our sample, of the orthogonally-rotated factors, smoking was only associated with the impulsivity and externalizing factor ([Formula: see text] - 0.82, 95% CI - 1.42, - 0.23). These differences may be due to correlations among outcomes that were accounted for by using a phenotypic approach. Dimension reduction may improve upon traditional approaches by accounting for correlations among neurodevelopmental traits.

Variability of urinary pesticide metabolite concentrations during pregnancy in the MARBLES Study

BACKGROUND

Variability of short-lived urinary pesticide metabolites during pregnancy raises challenges for exposure assessment.

OBJECTIVES

For urinary metabolite concentrations 3-phenoxybenzoic acid (3-PBA) and 3,5,6-trichloro-2-pyridinol (TCPy), we assessed: (1) temporal variability; (2) variation of two urine specimens within a trimester; (3) reliability for pesticide concentrations from a single urine specimen to classify participants into exposure tertiles; and (4) seasonal or year variations.

METHODS

Pregnant mothers (N = 166) in the MARBLES (Markers of Autism Risk in Babies-Learning Early Signs) Study provided urine specimens (n = 528). First morning void (FMV), pooled, and 24-h specimens were analyzed for 3-PBA and TCPy. For 9 mothers (n = 88 specimens), each urine specimen was analyzed separately (not pooled) to estimate within- and between-person variance components expressed as intraclass correlation coefficients (ICC). Pesticide concentrations from two specimens within a trimester were also assessed using ICC's. Agreement for exposure classifications was assessed with weighted Cohen's kappa statistics. Longitudinal mixed effect models were used to assess seasonal or year variations.

RESULTS

Urinary pesticide metabolites were detected in ≥ 93% of specimens analyzed. The highest ICC from repeated individual specimens was from specific gravity-corrected FMV specimens for 3-PBA (ICC=0.13). Despite high within-person variability, the median concentrations did not differ across trimesters. Concentrations from pooled specimens had substantial agreement predicting exposure categories for TCPy (K = 0.67, 95% CI (0.59, 0.76)) and moderate agreement for 3-PBA (K = 0.59, 95% CI (0.49, 0.69)). TCPy concentrations significantly decreased from 2007 to 2014.

CONCLUSIONS

Pooled specimens may improve exposure classification and reduce laboratory costs for compounds with short biological half-lives in epidemiological studies.

Effect of titanium dioxide nanoparticles on the bioavailability and neurotoxicity of cypermethrin in zebrafish larvae

In aquatic environment, the presence of nanoparticles (NPs) has been reported to modify the bioavailability and toxicity of the organic toxicants. Nevertheless, the combined toxicity of NPs and the pesticides that were used world-widely still remains unclear. Cypermethrin (CYP), a synthetic pyrethroid insecticide, is commonly used for controlling agricultural and indoor pests. Therefore, the effects of titanium dioxide NPs (nTiO₂) on CYP bioconcentration and its effects on the neuronal development in zebrafish were investigated in our study. Zebrafish embryos (2- hour-post-fertilization, hpf) were exposed to CYP (0, 0.4, 2 and 10 μg/L) alone or co-exposed with nTiO₂ (1 mg/L) until 120-hpf. nTiO₂ is taken up by zebrafish larvae and also it can adsorb CYP. The zebrafish body burdens of CYP was observed and CYP uptake was increased by nTiO₂, indicating that the nTiO₂ could accelerate the bioaccumulation of CYP in larvae. Co-exposure of nTiO₂ and CYP induced the generation of reactive oxygen species. Exposure to CYP alone significantly decreased the mRNA expression of genes, including glial fibrillary acidic protein (gfap), α1-tubulin, myelin basic protein (mbp) and growth associated protein (gap-43). Besides, reductions of serotonin, dopamine and GABA concentrations were observed in zebrafish and the larval locomotion was significantly decreased in response to the lower level of the neurotransmitters. Moreover, co-exposure of nTiO₂ and CYP caused further significantly decreased in the locomotion activity, and enhanced the down-regulation of the mRNA expression of specific genes and the neurotransmitters levels. The results demonstrated that nTiO₂ increased CYP accumulation and enhanced CYP-induced developmental neurotoxicity in zebrafish.

Oral exposure of deltamethrin and/or lipopolysaccharide (LPS) induced activation of the pulmonary immune system in Swiss albino mice

The deltamethrin, a synthetic pyrethroid, is used worldwide and has been linked with several type of acute toxicity. However, effect of low level of deltamethrin alone or in combination with the microbial antigen on pulmonary system is not understood. Lipopolysaccharide (LPS) was used as antigen which is a key inflammatory component of gram-negative bacteria, which induces a distinctive pattern of cytokine release that regulates inflammation. The aim was to determine whether chronic exposure to a low level of deltamethrin alone or in combination with LPS impair the lung response in adult male Swiss albino mice. The mice were orally exposed to different doses of deltamethrin (0.1, 0.05, 0.005, 0.001 mg/kg bwt) and then immunized with LPS at the 60th day. None of the treatment groups contained residues of deltamethrin above the limits of quantification. Deltamethrin combined with LPS challenge caused significant lymphocytosis and neutropenia in group 1 (0.1 mg/kg) mice (P < 0.05). The highest dose of deltamethrin exposure (0.1 mg/kg bwt) alone altered the total cell count significantly in blood and total leukocyte count (TLC) and macrophage count in bronchoalveolar lavage fluid. Microscopic pulmonary damage was evaluated by H&E staining and EM which indicated that two higher doses of deltamethrin, i.e., 0.1 and 0.05 mg/kg bwt, distinctly increased inflammatory cell infiltration and caused alveolar septa thickening and leukocyte infiltration into the alveolar septum (septal cell infiltration) in the lungs. Deltamethrin exposure alone and/or with endotoxin revealed different degrees of immunopositive reaction for Toll-like receptor 4 (TLR4) and pro-inflammatory cytokine-like tumor necrosis factor-alpha (TNFα) in different parts of the lungs. The expression of TLR4 and TNFα in the lung tissue was more pronounced in two higher dose groups. Thus, chronic low-level deltamethrin exposure may impair the main pro-inflammatory response in the lungs which is more pronounced in combination with LPS. Further research is required in direction of the mechanism of action of deltamethrin on the immune cell lineage and their differentiation.

Effects of pyrethroid pesticide cis-bifenthrin on lipogenesis in hepatic cell line

Mounting evidence suggests there is a link between exposure to synthetic pyrethroids (SPs) and the development of obesity. The information presented in this study suggests that cis-bifenthrin (cis-BF) could activate pregnane X receptor (PXR) mediated pathway and lead to the lipid accumulation of human hepatoma (HepG2) cells. Cells were incubated in the control or different concentrations of cis-BF for 24 h. The 1 × 10^-7 M and 1 × 10^-6 M cis-BF exposure were found to induce cellular triglyceride (TG) accumulation significantly. This phenomenon was further supported by Oil Red O Staining assay. The cis-BF exposure caused upregulation of PXR gene and protein. Correspondingly, we also observed the increased expression of downstream genes involved in lipid formation and the inhibition of the expression of β-oxidation. As chiral pesticide，cis-BF was further conformed to behave enantioselectivity in the lipid metabolism. Rather than 1R-cis-BF, HepG2 cells incubated with 1S-cis-BF exhibited a significant TG accumulation. 1S-cis-BF also showed a higher binding level, of which the KD value was 9.184 × 10^-8 M in the SPR assay, compared with 1R-cis-BF (3.463 × 10^-6 M). In addition, the molecular docking simulation analyses correlated well with the KD values measured by the SPR, indicating that 1S-cis-BF showed a better binding affinity with PXR. The results in this study also elucidates the differences between the two enantiomers of pyrethroid-induced toxicity in lipid metabolism of non-target organism.

Sublethal chronic effects of oral dietary exposure to deltamethrin in Swiss albino mice

The hazards of dietary exposure to environmentally relevant levels of deltamethrin are poorly understood though studies enunciate the acute toxicity hazards. In this study, prolonged exposure to low levels of deltamethrin in mice was investigated. The mice were exposed daily via gavage method for 60 days. Four doses (0.1, 0.05, 0.01, and 0.005 mg/kg bwt/d) were selected, which are equal to or less than the maximum residue limits for deltamethrin permitted in animal food/feed. Liver, kidney, lungs, spleen, and testes were collected on day 61 for histology, residue, and biochemical analysis (aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALKP), total bilirubin (TBIL), total proteins (TPs), cholesterol (CHOL), urea, and creatinine). No significant changes were observed in body weight gain in all treatment groups ( p > 0.05). The gas chromatography analysis indicated that none of the tissue samples contained deltamethrin residues above the limits of quantification. The significant differences in biochemical profile (AST, ALT, TBIL, and creatinine) reported in animals exposed to 0.1 and 0.05 mg/kg bwt/d deltamethrin ( p < 0.05) suggest respective tissue injury and lipid peroxidation; however, few significant changes in urea and CHOL were also reported in doses 0.01 and 0.005 mg/kg bwt. No significant differences in TP and ALKP were observed ( p > 0.05). The target organs for deltamethrin toxicity showed prominent histopathological changes in concentrations of 0.1 and 0.05 mg/kg bwt. Other two doses showed no or sporadic changes. Our findings suggest that chronic exposure to environmentally relevant levels of deltamethrin can have detrimental effects on vital organs in the circumstances allowing daily exposure, in congruence with available literature.

Prenatal exposure to organophosphorus pesticides and childhood neurodevelopmental phenotypes

Prenatal exposure to organophosphorus pesticides (OPs) has been associated with different neurodevelopmental outcomes across different cohorts. A phenotypic approach may address some of these differences by incorporating information across scales and accounting for the complex correlational structure of neurodevelopmental outcomes. Additionally, Bayesian hierarchical modeling can account for confounding by collinear co-exposures. We use this framework to examine associations between prenatal exposure to OPs and behavior, executive functioning, and IQ assessed at age 6-9 years in a cohort of 404 mother/infant pairs recruited during pregnancy. We derived phenotypes of neurodevelopment with a factor analysis, and estimated associations between OP metabolites and these phenotypes in Bayesian hierarchical models for exposure mixtures. We report seven factors: 1) Impulsivity and Externalizing, 2) Executive Functioning, 3) Internalizing, 4) Perceptual Reasoning, 5) Adaptability, 6) Processing Speed, and 7) Verbal Intelligence. These, along with the Working Memory Index, were standardized and scaled so that positive values reflected positive attributes and negative values represented adverse outcomes. Standardized dimethylphosphate metabolites were negatively associated with Internalizing factor scores (β^ - 0.13, 95% CI - 0.26, 0.00) but positively associated with Executive Functioning factor scores (β^ 0.18, 95% CI 0.04, 0.31). Standardized diethylphosphate metabolites were negatively associated with the Working Memory Index (β^ - 0.17, 95% CI - 0.33, - 0.03). Associations with factor scores were generally stronger and more precise than associations with individual instrument-specific items. Factor analysis of outcomes may provide some advantages in etiological studies of childhood neurodevelopment by incorporating information across scales to reduce dimensionality and improve precision.

Prenatal exposure to pyrethroid pesticides and childhood behavior and executive functioning

Several previous studies of pyrethroid biomarkers and behavior have reported associations between concurrent pyrethroid levels and adverse behavioral problems in children. One geospatial study reported associations between prenatal exposure to pyrethroids and autism. However, the association between prenatal pyrethroid biomarkers and childhood behavior is unknown. The Mount Sinai Children's Environmental Health Center is a prospective birth cohort with urinary pyrethroid biomarkers during pregnancy and behavioral measurements at 4, 6, and 7-9 years of age. Primiparous women were enrolled between 1998 and 2002. 162 mother/child pairs with complete exposure and behavioral outcomes data were used to investigate associations between detectable levels of prenatal pyrethroid metabolites and scores on the Behavioral Assessment System for Children and the Behavior Rating Inventory of Executive Function. Overall, detection frequencies of pyrethroid metabolites were low (<30%). In longitudinal mixed models, detectable levels of 3-PBA during pregnancy were associated with worse Internalizing (β -4.50, 95% CI -8.05, -0.95), Depression (β -3.21, 95% CI -6.38, -0.05), Somatization (β -3.22, 95% CI -6.38, -0.06), Behavioral Regulation (β -3.59, 95% CI -6.97, -0.21), Emotional Control (β -3.35, 95% CI -6.58, -0.12), Shifting (β -3.42, 95% CI -6.73, -0.11), and Monitoring (β -4.08, 95% CI -7.07, -1.08) scales. Detectable levels of cis-DCCA were associated with worse Externalizing (β -4.74, 95% CI -9.37, -0.10), Conduct Problems (β -5.35, 95% CI -9.90, -0.81), Behavioral Regulation (β -6.42, 95% CI -11.39, -1.45), and Inhibitory Control (β -7.20, 95% CI -12.00, -2.39). Although detection frequencies of pyrethroid metabolites were low, we found suggestive evidence that prenatal exposure to 3-PBA and cis-DCCA may be associated with a variety of behavioral and executive functioning deficits.

Impact of dust exposure on mixed bacterial cultures and during eukaryotic cell co-culture infections

On a daily basis, humans, and their colonizing microbiome, are exposed to both indoor and outdoor dust, containing both deleterious organic and inorganic contaminants, through dermal contact, inhalation, and ingestion. Recent studies evaluating the dust exposure responses of opportunistic pathogens, such as Escherichia coli and Pseudomonas aeruginosa, revealed significant increases in biofilm formation following dust exposure. In this study, the effects of dust exposure on mixed bacterial cultures as well as HT-29 co-cultures were evaluated. As it was observed in pure, single bacterial cultures earlier, neither indoor nor outdoor dust exposure (at concentrations of 100 μg/mL) influenced the growth of mixed bacterial liquid cultures. However, when in paired mixed cultures, dust exposure increased sensitivity to oxidative stress and significantly enhanced biofilm formation (outdoor dust). More specifically, mixed cultures (E. coli-Klebsiella pneumoniae, K. pneumoniae-P. aeruginosa, and E. coli-P. aeruginosa) exhibited increased sensitivity to 20 and 50 mM of H₂O₂ in comparison to their pure, single bacterial culture counterparts and significantly enhanced biofilm production for each mixed culture. Finally, bacterial proliferation during a eukaryotic gut cell (HT29) co-culture was significantly more robust for both K. pneumoniae and P. aeruginosa when exposed to both house and road dust; however, E. coli only experienced significantly enhanced proliferation, in HT29 co-culture, when exposed to road dust. Taken together, our findings demonstrate that bacteria respond to dust exposure differently when in the presence of multiple bacterial species or when in the presence of human gut epithelial cells, than when grown in isolation.

"Exposure to the insecticides permethrin and malathion induces leukemia and lymphoma-associated gene aberrations in vitro"

Epidemiological studies have associated the exposure to permethrin and malathion with increased risk of leukemia and lymphoma. The aim of this study was to evaluate whether in vitro exposure to permethrin and malathion induces aberrations in genes involved in the etiology of these hematological malignancies. Genetic abnormalities in the IGH, KMT2A (MLL), ETV6 and RUNX1 genes, and aneuploidy induced by the in vitro exposure to permethrin and malathion (200μM, 24h), were analyzed by FISH in peripheral blood mononuclear cells (PBMCs). The gene fusions IGH-BCL2, KMT2A-AFF1 and ETV6-RUNX1 were further analyzed with nested RT-PCR in PBMCs, and in K562 cells exposed to acute and chronic treatments (0.1μM, 24h or every third day for two weeks) of insecticides. FISH analysis revealed that permethrin induces aneuploidy and structural alterations in IGH and KMT2A genes, and malathion induces breaks in KMT2A. RT-PCR detected ETV6-RUNX1 fusion in PBMCs acutely exposed to permethrin. Permethrin also induced ETV6-RUNX1 and IGH-BCL2 fusions in K562 cells, and malathion induced KMT2A-AFF1 and ETV6-RUNX1 fusions. Overall, we identified that both insecticides induce breaks and fusions in the studied genes, and permethrin induces aneuploidy. This study presents evidence of damage in cancer genes caused by these insecticides.

Prenatal Residential Proximity to Agricultural Pesticide Use and IQ in 7-Year-Old Children

BACKGROUND

Residential proximity to agricultural pesticide use has been associated with neural tube defects and autism, but more subtle outcomes such as cognition have not been studied.

OBJECTIVES

We evaluated the relationship between prenatal residential proximity to agricultural use of potentially neurotoxic pesticides and neurodevelopment in 7-year-old children.

METHODS

Participants included mothers and children (n=283) living in the agricultural Salinas Valley of California enrolled in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study. We estimated agricultural pesticide use within 1 km of maternal residences during pregnancy using a geographic information system, residential location, and California’s comprehensive agricultural Pesticide Use Report data. We used regression models to evaluate prenatal residential proximity to agricultural use of five potentially neurotoxic pesticide groups (organophosphates, carbamates, pyrethroids, neonicotinoids, and manganese fungicides) and five individual organophosphates (acephate, chlorpyrifos, diazinon, malathion, and oxydemeton-methyl) and cognition in 7-year-old children. All models included prenatal urinary dialkyl phosphate metabolite concentrations.

RESULTS

We observed a decrease of 2.2 points [95% confidence interval (CI): −3.9, −0.5] in Full-Scale IQ and 2.9 points (95% CI: −4.4, −1.3) in Verbal Comprehension for each standard deviation increase in toxicity-weighted use of organophosphate pesticides. In separate models, we observed similar decrements in Full-Scale IQ with each standard deviation increase of use for two organophosphates (acephate and oxydemeton-methyl) and three neurotoxic pesticide groups (pyrethroids, neonicotinoids, and manganese fungicides).

CONCLUSIONS

This study identified potential relationships between maternal residential proximity to agricultural use of neurotoxic pesticides and poorer neurodevelopment in children. https://doi.org/10.1289/EHP504.

Distributions and determinants of urinary biomarkers of organophosphate pesticide exposure in a prospective Spanish birth cohort study

BACKGROUND

Prenatal exposure to organophosphate pesticides (OPs) has been associated with impaired child development. Pesticide exposure determinants need to be studied in order to identify sources and pathways of pesticide exposure. The aim of this paper is to describe prenatal exposure to OPs and evaluate the associated factors in pregnant women.

METHODS

The study population consisted of pregnant women (n = 573) who participated in the INMA birth cohort study in Valencia (Spain, 2003-2006). OP metabolites were analyzed in maternal urine at the 32nd week of gestation using a liquid chromatography-high resolution mass spectrometry method. The analysis included non-specific (diethyl phosphate [DEP], diethyl thiophosphate [DETP], dimethyl thiophosphate [DMTP], dimethyl dithiophosphate [DMDTP]) and specific metabolites (2-diethylamino-6-methyl-4-pyrimidinol [DEAMPY], 2-isopropyl-4-methyl-6-hydroxypyrimidine [IMPY], para-nitrophenol [PNP], and 3,5,6-trichloro-2-pyridinol [TCPY]). Information about the sociodemographic, environmental, and dietary characteristics was obtained by questionnaire. The association between log-transformed OPs and covariates was analyzed using multivariable interval censored regression.

RESULTS

The detection frequencies were low, DMTP and TCPY being the most frequently detected metabolites (53.8% and 39.1%, respectively). All the OP metabolites were positively associated with maternal intake of fruits and vegetables. Other maternal characteristics related to the OPs were body mass index (BMI) before pregnancy and smoking habit during pregnancy. Women with lower BMI and those who did not smoke presented higher OP concentrations. Moreover, mothers who had a yard or garden with plants at home or who lived in an urban area were also more exposed to OPs.

CONCLUSIONS

The OP detection frequencies and the concentrations observed in our study population were low, compared with most of the previously published studies. Given the high vulnerability of the fetus to neurotoxicant exposure, further research on the determinants of the body burden of OPs during pregnancy would be necessary. The knowledge gained from such studies would enhance the effectiveness of public health control and future recommendations in order to reduce the risk to both the health of pregnant women and the health and development of their children.

Transcriptome analysis of zebrafish embryos exposed to deltamethrin

Deltamethrin (DTM), a type II pyrethroid, is one of the most commonly used insecticides. The increased use of pyrethroid leads to potential adverse effects, particularly in sensitive populations such as children and pregnant women. None of the related studies was focused on the transcriptome responses in zebrafish embryos after treatment with DTM; therefore, RNA-seq, a high-throughput method, was performed to analyze the global expression of differential expressed genes (DEGs) in zebrafish embryos treated with DTM (40 and 80 μg/L) from fertilization to 48 h postfertilization (hpf) as compared with that in the control group (without DTM treatment). Two cDNA libraries were generated from treated embryos and one cDNA library from nontreated embryos, respectively. Over 92% of reads mapped to the reference in these three libraries. It was observed that many differential genes were expressed in comparison with embryos before and after DTM. The 20 most differentially expressed upregulated or downregulated genes were majorly involved in the signaling transduction. Validation of selected nine genes expression using qRT-PCR confirmed RNA-seq results. The transcriptome sequences were further subjected to gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, showing G-protein-coupled receptor signaling pathway and neuroactive ligand-receptor interaction, respectively, were most enriched. The data from this study contributed to a better understanding of the potential consequences of fish exposed to DTM, to an evaluation of the potential threat of DTM to fish populations in aquatic environments. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1548-1557, 2017.