Neurodevelopmental Toxicity - HH-RA.org

Bibliography Tag: neurodevelopmental toxicity

Kokroko et al., 2020

Kokroko, J., Kogut, K., Harley, K., & Eskenazi, B.; “Prenatal beta-Hexachlorocyclohexane (beta-HCH) Exposure and 7-Year Child IQ in the CHAMACOS Birth Cohort;” Neurotoxicity Research, 2020, 37(3), 553-563; DOI: 10.1007/s12640-020-00160-w.

ABSTRACT:

Fetal and infant exposures to beta-hexachlorocyclohexane (beta-HCH) occur through placental and breastmilk transfers. No studies have examined the relationship between beta-HCH and child intelligence quotient (IQ). This study examined associations between in utero beta-HCH exposure and cognitive development in 7-year-old children. Data from women and children (n = 256) participating in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) birth cohort study were evaluated. We assessed exposure to beta-HCH by measuring maternal serum concentration during pregnancy. We administered the Wechsler Intelligence Scale for Children (WISC), Fourth Edition, to children at age 7. Analyses were adjusted for maternal age, country of birth, work status, parity, and other pesticide exposures, language used for child cognitive assessment, and duration of breastfeeding. Higher serum beta-HCH concentrations were associated with higher cognitive scores across all unadjusted models for the full-scale and sub-scale cognitive tests. In the adjusted models, a 10-fold increase in serum beta-HCH concentration was associated with a 4.5-point increase in Working Memory IQ score (95% CI, 0.6 to 8.3; p = 0.02). We observed no significant interaction by length of breastfeeding or sex on associations. Our findings suggest that prenatal exposure to beta-HCH is not adversely related to IQ at age 7 in a cohort of Mexican American children with fairly high exposure in utero as measured by maternal serum levels. Future research must replicate these findings in other study cohorts of women and children.

Bakian and VanDerslice, 2019

Bakian, Amanda V., & VanDerslice, James A.; “Pesticides and autism;” BMJ, 2019, 364, l1149; DOI: 10.1136/bmj.l1149.

ABSTRACT:

Not Available

FULL TEXT

Zhang et al., 2018

Zhang, M., Ma, W., Zhang, J., He, Y., & Wang, J.; “Analysis of gut microbiota profiles and microbe-disease associations in children with autism spectrum disorders in China;” Scientific Reports, 2018, 8(1), 13981; DOI: 10.1038/s41598-018-32219-2.

ABSTRACT:

Autism spectrum disorder (ASD) is a set of complex neurodevelopmental disorders. Recent studies reported that children with ASD have altered gut microbiota profiles compared with typical development (TD) children. However, few studies on gut bacteria of children with ASD have been conducted in China. Here, in order to elucidate changes of fecal microbiota in children with ASD, 16S rRNA sequencing was conducted and the 16S rRNA (V3-V4) gene tags were amplified. We investigated differences in fecal microbiota between 35 children with ASD and 6 TD children. At the phylum level, the fecal microbiota of ASD group indicated a significant increase of the Bacteroidetes/Firmicutes ratio. At the genus level, we found that the relative abundance of Sutterella, Odoribacter and Butyricimonas was much more abundant in the ASD group whereas the abundance of Veillonella and Streptococcus was decreased significantly compared to the control group. Functional analysis demonstrated that butyrate and lactate producers were less abundant in the ASD group. In addition, we downloaded the association data set of microbe-disease from human microbe-disease association database and constructed a human disease network including ASD using our gut microbiome results. In this microbe-disease network based on microbe similarity of diseases, we found that ASD is positively correlated with periodontal, negatively related to type 1 diabetes. Therefore, these results suggest that microbe-based disease analysis is able to predict novel connection between ASD and other diseases and may play a role in revealing the pathogenesis of ASD. FULL TEXT

Zhang et al., 2020

Zhang, M., Chu, Y., Meng, Q., Ding, R., Shi, X., Wang, Z., He, Y., Zhang, J., Liu, J., Zhang, J., Yu, J., Kang, Y., & Wang, J.; “A quasi-paired cohort strategy reveals the impaired detoxifying function of microbes in the gut of autistic children;” Science Advances, 2020, 6(43); DOI: 10.1126/sciadv.aba3760.

ABSTRACT:

Growing evidence suggests that autism spectrum disorder (ASD) is strongly associated with dysbiosis in the gut microbiome, with the exact mechanisms still unclear. We have proposed a novel analytic strategy-quasi-paired cohort-and applied it to a metagenomic study of the ASD microbiome. By comparing paired samples of ASD and neurotypical subjects, we have identified significant deficiencies in ASD children in detoxifying enzymes and pathways, which show a strong correlation with biomarkers of mitochondrial dysfunction. Diagnostic models based on these detoxifying enzymes accurately distinguished ASD individuals from controls, and the dysfunction score inferred from the model increased with the clinical rating scores of ASD. In summary, our results suggest a previously undiscovered potential role of impaired intestinal microbial detoxification in toxin accumulation and mitochondrial dysfunction, a core component of ASD pathogenesis. These findings pave the way for designing future therapeutic strategies to restore microbial detoxification capabilities for patients with ASD. FULL TEXT

Ruden and Grandjean, 2018

Mie, A., Ruden, C., & Grandjean, P.; “Safety of Safety Evaluation of Pesticides: developmental neurotoxicity of chlorpyrifos and chlorpyrifos-methyl;” Environmental Health, 2018, 17(1), 77; DOI: 10.1186/s12940-018-0421-y.

ABSTRACT:

Authorization of pesticides for market release requires toxicity testing on animals, typically performed by test laboratories on contract with the pesticide producer. The latter provides the results and summary to the regulatory authorities. For the commonly used pesticide chlorpyrifos, an industry-funded toxicity study concludes that no selective effects on neurodevelopment occur even at high exposures. In contrast, the evidence from independent studies points to adverse effects of current exposures on cognitive development in children. We reviewed the industry-funded developmental neurotoxicity test data on chlorpyrifos and the related substance chlorpyrifos-methyl. We noted treatment-related changes in a brain dimension measure for chlorpyrifos at all dose levels tested, although not been reported in the original test summary. We further found issues which inappropriately decrease the ability of the studies to reveal true effects, including a dosage regimen that resulted in too low exposure of the nursing pups for chlorpyrifos and possibly for chlorpyrifos-methyl, and a failure to detect any neurobehavioral effects of lead nitrate used as positive control in the chlorpyrifos study. Our observations thus suggest that conclusions in test reports submitted by the producer may be misleading. This discrepancy affects the ability of regulatory authorities to perform a valid and safe evaluation of these pesticides. The difference between raw data and conclusions in the test reports indicates a potential existence of bias that would require regulatory attention and possible resolution. FULL TEXT

Pellizzari et al., 2019

Pellizzari, E. D., Woodruff, T. J., Boyles, R. R., Kannan, K., Beamer, P. I., Buckley, J. P., Wang, A., Zhu, Y., & Bennett, D. H.; “Identifying and Prioritizing Chemicals with Uncertain Burden of Exposure: Opportunities for Biomonitoring and Health-Related Research;” Environmental Health Perspectives, 2019, 127(12), 126001; DOI: 10.1289/EHP5133.

ABSTRACT:

BACKGROUND: The National Institutes of Health’s Environmental influences on Child Health Outcomes (ECHO) initiative aims to understand the impact of environmental factors on childhood disease. Over 40,000 chemicals are approved for commercial use. The challenge is to prioritize chemicals for biomonitoring that may present health risk concerns.

OBJECTIVES: Our aim was to prioritize chemicals that may elicit child health effects of interest to ECHO but that have not been biomonitored nationwide and to identify gaps needing additional research.

METHODS: We searched databases and the literature for chemicals in environmental media and in consumer products that were potentially toxic. We selected chemicals that were not measured in the National Health and Nutrition Examination Survey. From over 700 chemicals, we chose 155 chemicals and created eight chemical panels. For each chemical, we compiled biomonitoring and toxicity data, U.S. Environmental Protection Agency exposure predictions, and annual production usage. We also applied predictive modeling to estimate toxicity. Using these data, we recommended chemicals either for biomonitoring, to be deferred pending additional data, or as low priority for biomonitoring.

RESULTS: For the 155 chemicals, 97 were measured in food or water, 67 in air or house dust, and 52 in biospecimens. We found in vivo endocrine, developmental, reproductive, and neurotoxic effects for 61, 74, 47, and 32 chemicals, respectively. Eighty-six had data from high-throughput in vitro assays. Positive results for endocrine, developmental, neurotoxicity, and obesity were observed for 32, 11, 35, and 60 chemicals, respectively. Predictive modeling results suggested 90% are toxicants. Biomarkers were reported for 76 chemicals. Thirty-six were recommended for biomonitoring, 108 deferred pending additional research, and 11 as low priority for biomonitoring.

DISCUSSION: The 108 deferred chemicals included those lacking biomonitoring methods or toxicity data, representing an opportunity for future research. Our evaluation was, in general, limited by the large number of unmeasured or untested chemicals. FULL TEXT

Buckley et al., 2020

Buckley, J. P., Barrett, E. S., Beamer, P. I., Bennett, D. H., Bloom, M. S., Fennell, T. R., Fry, R. C., Funk, W. E., Hamra, G. B., Hecht, S. S., Kannan, K., Iyer, R., Karagas, M. R., Lyall, K., Parsons, P. J., Pellizzari, E. D., Signes-Pastor, A. J., Starling, A. P., Wang, A., Watkins, D. J., Zhang, M., Woodruff, T. J., & program collaborators for, Echo; “Opportunities for evaluating chemical exposures and child health in the United States: the Environmental influences on Child Health Outcomes (ECHO) Program;” Journal of exposure science & environmental epidemiology, 2020, 30(3), 397-419; DOI: 10.1038/s41370-020-0211-9.

ABSTRACT:

The Environmental Influences on Child Health Outcomes (ECHO) Program will evaluate environmental factors affecting children’s health (perinatal, neurodevelopmental, obesity, respiratory, and positive health outcomes) by pooling cohorts composed of >50,000 children in the largest US study of its kind. Our objective was to identify opportunities for studying chemicals and child health using existing or future ECHO chemical exposure data. We described chemical-related information collected by ECHO cohorts and reviewed ECHO-relevant literature on exposure routes, sources, and environmental and human monitoring. Fifty-six ECHO cohorts have existing or planned chemical biomonitoring data for mothers or children. Environmental phenols/parabens, phthalates, metals/metalloids, and tobacco biomarkers are each being measured by ≥15 cohorts, predominantly during pregnancy and childhood, indicating ample opportunities to study child health outcomes. Cohorts are collecting questionnaire data on multiple exposure sources and conducting environmental monitoring including air, dust, and water sample collection that could be used for exposure assessment studies. To supplement existing chemical data, we recommend biomonitoring of emerging chemicals, nontargeted analysis to identify novel chemicals, and expanded measurement of chemicals in alternative biological matrices and dust samples. ECHO’s rich data and samples represent an unprecedented opportunity to accelerate environmental chemical research to improve the health of US children. FULL TEXT

Berkowitz et al., 2004

Berkowitz, G. S., Wetmur, J. G., Birman-Deych, E., Obel, J., Lapinski, R. H., Godbold, J. H., Holzman, I. R., & Wolff, M. S.; “In utero pesticide exposure, maternal paraoxonase activity, and head circumference;” Environmental Health Perspectives, 2004, 112(3), 388-391; DOI: 10.1289/ehp.6414.

ABSTRACT:

Although the use of pesticides in inner-city homes of the United States is of considerable magnitude, little is known about the potentially adverse health effects of such exposure. Recent animal data suggest that exposure to pesticides during pregnancy and early life may impair growth and neurodevelopment in the offspring. To investigate the relationship among prenatal pesticide exposure, paraoxonase (PON1) polymorphisms and enzyme activity, and infant growth and neurodevelopment, we are conducting a prospective, multiethnic cohort study of mothers and infants delivered at Mount Sinai Hospital in New York City. In this report we evaluate the effects of pesticide exposure on birth weight, length, head circumference, and gestational age among 404 births between May 1998 and May 2002. Pesticide exposure was assessed by a prenatal questionnaire administered to the mothers during the early third trimester as well as by analysis of maternal urinary pentachlorophenol levels and maternal metabolites of chlorpyrifos and pyrethroids. Neither the questionnaire data nor the pesticide metabolite levels were associated with any of the fetal growth indices or gestational age. However, when the level of maternal PON1 activity was taken into account, maternal levels of chlorpyrifos above the limit of detection coupled with low maternal PON1 activity were associated with a significant but small reduction in head circumference. In addition, maternal PON1 levels alone, but not PON1 genetic polymorphisms, were associated with reduced head size. Because small head size has been found to be predictive of subsequent cognitive ability, these data suggest that chlorpyrifos may have a detrimental effect on fetal neurodevelopment among mothers who exhibit low PON1 activity. FULL TEXT

Dechartres et al., 2019

Dechartres, J., Pawluski, J. L., Gueguen, M. M., Jablaoui, A., Maguin, E., Rhimi, M., & Charlier, T. D.; “Glyphosate and glyphosate-based herbicide exposure during the peripartum period affects maternal brain plasticity, maternal behaviour and microbiome;” Journal of Neuroendocrinology, 2019, 31(9), e12731; DOI: 10.1111/jne.12731.

ABSTRACT:

Glyphosate is found in a large array of non-selective herbicides such as Roundup(R) (Monsanto, Creve Coeur, MO, USA) and is by far the most widely used herbicide. Recent work in rodent models suggests that glyphosate-based herbicides during development can affect neuronal communication and result in altered behaviours, albeit through undefined mechanisms of action. To our knowledge, no study has investigated the effects glyphosate or its formulation in herbicide on maternal behaviour and physiology. In the present study, relatively low doses of glyphosate (5 mg kg(-1) d(-1) ), Roundup(R) (5 mg kg(-1) d(-1) glyphosate equivalent), or vehicle were administered by ingestion to Sprague-Dawley rats from gestational day (GD) 10 to postpartum day (PD)22. The treatments significantly altered licking behaviour toward pups between PD2 and PD6. We also show in the dams at PD22 that Roundup exposure affected the maturation of doublecortin-immunoreactive new neurones in the dorsal dentate gyrus of the hippocampus of the mother. In addition, the expression of synaptophysin was up-regulated by glyphosate in the dorsal and ventral dentate gyrus and CA3 regions of the hippocampus, and down-regulated in the cingulate gyrus. Although a direct effect of glyphosate alone or its formulation on the central nervous system is currently not clear, we show that gut microbiota is significantly altered by the exposure to the pesticides, with significant alteration of the phyla Bacteroidetes and Firmicutes. This is the first study to provide evidence that glyphosate alone or in formulation (Roundup) differentially affects maternal behaviour and modulates neuroplasticity and gut microbiota in the mother. FULL TEXT

Meftaul et al.; 2020

Meftaul, I. M., Venkateswarlu, K., Dharmarajan, R., Annamalai, P., Asaduzzaman, M., Parven, A., & Megharaj, M.; “Controversies over human health and ecological impacts of glyphosate: Is it to be banned in modern agriculture?;” Environmental Pollution, 2020, 263(Pt A), 114372; DOI: 10.1016/j.envpol.2020.114372.

ABSTRACT:

Glyphosate, introduced by Monsanto Company under the commercial name Roundup in 1974, became the extensively used herbicide worldwide in the last few decades. Glyphosate has excellent properties of fast sorption in soil, biodegradation and less toxicity to nontarget organisms. However, glyphosate has been reported to increase the risk of cancer, endocrine-disruption, celiac disease, autism, effect on erythrocytes, leaky-gut syndrome, etc. The reclassification of glyphosate in 2015 as ‘probably carcinogenic’ under Group 2A by the International Agency for Research on Cancer has been broadly circulated by anti-chemical and environmental advocacy groups claiming for restricted use or ban of glyphosate. In contrast, some comprehensive epidemiological studies involving farmers with long-time exposure to glyphosate in USA and elsewhere coupled with available toxicological data showed no correlation with any kind of carcinogenic or genotoxic threat to humans. Moreover, several investigations confirmed that the surfactant, polyethoxylated tallow amine (POEA), contained in the formulations of glyphosate like Roundup, is responsible for the established adverse impacts on human and ecological health. Subsequent to the evolution of genetically modified glyphosate-resistant crops and the extensive use of glyphosate over the last 45 years, about 38 weed species developed resistance to this herbicide. Consequently, its use in the recent years has been either restricted or banned in 20 countries. This critical review on glyphosate provides an overview of its behaviour, fate, detrimental impacts on ecological and human health, and the development of resistance in weeds and pathogens. Thus, the ultimate objective is to help the authorities and agencies concerned in resolving the existing controversies and in providing the necessary regulations for safer use of the herbicide. In our opinion, glyphosate can be judiciously used in agriculture with the inclusion of safer surfactants in commercial formulations sine POEA, which is toxic by itself is likely to increase the toxicity of glyphosate. FULL TEXT

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