1
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Non-traditional stable isotopic analysis for source tracing of atmospheric particulate matter. Trends Analyt Chem 2023. [DOI: 10.1016/j.trac.2022.116866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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2
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Cecil KM. Pediatric Exposures to Neurotoxicants: A Review of Magnetic Resonance Imaging and Spectroscopy Findings. Diagnostics (Basel) 2022; 12:diagnostics12030641. [PMID: 35328193 PMCID: PMC8947432 DOI: 10.3390/diagnostics12030641] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/28/2022] [Accepted: 03/03/2022] [Indexed: 12/04/2022] Open
Abstract
Heavy metals, including lead and manganese, air pollution, pesticides, environmental tobacco smoke, and flame retardants are among the known and suspected environmental neurotoxicant exposures examined with magnetic resonance imaging (MRI)-based studies of pediatric populations. Many studies feature morphological changes associated with the exposures while others employ magnetic resonance spectroscopy, diffusion imaging, task-based, and resting state functional magnetic resonance imaging to reveal abnormal metabolic concentrations, white matter disorganization, and atypical patterns of activation. Some studies follow pregnant women and their offspring throughout the lifespan with collection of individual specimens as exposure biomarkers. Others innovatively make use of public databases to obtain relevant exposure biomarkers while taking advantage of these studies in their efforts to monitor developmental features in large, population-based, imaging cohorts. As exposures to neurotoxicants in the womb and throughout childhood have life-long impacts on health and well-being, the importance of these innovative neuroimaging investigations is ever increasing.
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Affiliation(s)
- Kim M Cecil
- Departments of Radiology and Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
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3
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Cruz GB, Vasquez MA, Cabañas E, Joseph JN, Skeen JC, Lynch KP, Ahmed I, Khairi EB, Bonitto JR, Clarke EG, Rubi S, Hameed N, Kaur S, Mathew N, Dacius TF, Jose TJ, Handford G, Wolfe S, Feher A, Tidwell K, Tobin J, Ugalde E, Fee S, Choe A, Gillenwater K, Hindi B, Pilout S, Natale NR, Domahoski N, Kent MH, Jacob JC, Lambert KG, Neuwirth LS. Developmental Lead Exposure in Rats Causes Sex-Dependent Changes in Neurobiological and Anxiety-Like Behaviors that Are Improved by Taurine Co-treatment. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1370:461-479. [DOI: 10.1007/978-3-030-93337-1_43] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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4
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Veta J, Singh KV, Bhattacharya A. Study Correlating Lead (Pb) Level Exposure and Bone Shock Absorption Capacity Based on Damping Associated With Higher Modes of Vibration. JOURNAL OF ENGINEERING AND SCIENCE IN MEDICAL DIAGNOSTICS AND THERAPY 2021; 4:034501. [PMID: 35832398 PMCID: PMC8597550 DOI: 10.1115/1.4050862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 04/08/2021] [Indexed: 06/15/2023]
Abstract
Noninvasive vibration testing is one of the tools for characterizing the biomechanical properties of bones and muscle groups in humans and animals. They present alternatives for evaluating bone health quality and may serve as early indicators for bone fragility and bone-related diseases. In recent years, a vibration-based bone shock absorption (BSA) method has shown potential to relate the damping capacity associated with the fundamental (first) vibration modes for developing dynamic bone quality indicators for osteoporosis patients. This research presents a study of early life (birth to age 78 months) lead (Pb) exposure on the damping capacity (bone fragility measures) with the bone shock absorption method. The damping ratio corresponding to few vibration modes is extracted and analyzed using clinical bone shock absorption data of patients with different Pb exposure levels. A method is developed for clustering and identifying three dominant vibration modes and their corresponding damping ratio. The statistical correlation between the damping parameters associated with higher vibration modes and Pb exposure level is presented here. This study highlights the importance of analyzing higher vibration modes and their damping capacity, which could be used to predict early diagnostics precursors of the bone- and/or muscle-related conditions or disorders.
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Affiliation(s)
- Jacob Veta
- Mechanical and Manufacturing Engineering Department, Miami University, 650 E. High Street, 056 GAR, Oxford, OH 45056
| | - Kumar V. Singh
- Mechanical and Manufacturing Engineering Department, Miami University, 650 E. High Street, 056 GAR, Oxford, OH 45056
| | - Amit Bhattacharya
- Department of Environmental Health, College of Medicine, University of Cincinnati, 160 Panzeca Way, Cincinnati, OH 45267-0056
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5
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Takeuchi H, Taki Y, Nouchi R, Yokoyama R, Kotozaki Y, Nakagawa S, Sekiguchi A, Iizuka K, Hanawa S, Araki T, Miyauchi CM, Sakaki K, Nozawa T, Ikeda S, Yokota S, Daniele M, Sassa Y, Kawashima R. Lead exposure is associated with functional and microstructural changes in the healthy human brain. Commun Biol 2021; 4:912. [PMID: 34312468 PMCID: PMC8313694 DOI: 10.1038/s42003-021-02435-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 07/06/2021] [Indexed: 02/07/2023] Open
Abstract
Lead is a toxin known to harm many organs in the body, particularly the central nervous system, across an individual's lifespan. To date, no study has yet investigated the associations between body lead level and the microstructural properties of gray matter areas, and brain activity during attention-demanding tasks. Here, utilizing data of diffusion tensor imaging, functional magnetic resonance imaging and cognitive measures among 920 typically developing young adults, we show greater hair lead levels are weakly but significantly associated with (a) increased working memory-related activity in the right premotor and pre-supplemental motor areas, (b) lower fractional anisotropy (FA) in white matter areas near the internal capsule, (c) lower mean diffusivity (MD) in the dopaminergic system in the left hemisphere and other widespread contingent areas, and (d) greater MD in the white matter area adjacent to the right fusiform gyrus. Higher lead levels were also weakly but significantly associated with lower performance in tests of high-order cognitive functions, such as the psychometric intelligence test, greater impulsivity measures, and higher novelty seeking and extraversion. These findings reflect the weak effect of daily lead level on the excitability and microstructural properties of the brain, particularly in the dopaminergic system.
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Affiliation(s)
- Hikaru Takeuchi
- grid.69566.3a0000 0001 2248 6943Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Yasuyuki Taki
- grid.69566.3a0000 0001 2248 6943Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan ,grid.69566.3a0000 0001 2248 6943Division of Medical Neuroimaging Analysis, Department of Community Medical Supports, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan ,grid.69566.3a0000 0001 2248 6943Department of Radiology and Nuclear Medicine, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Rui Nouchi
- grid.69566.3a0000 0001 2248 6943Creative Interdisciplinary Research Division, Frontier Research Institute for Interdisciplinary Science, Tohoku University, Sendai, Japan ,grid.69566.3a0000 0001 2248 6943Human and Social Response Research Division, International Research Institute of Disaster Science, Tohoku University, Sendai, Japan ,grid.69566.3a0000 0001 2248 6943Department of Advanced Brain Science, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Ryoichi Yokoyama
- grid.31432.370000 0001 1092 3077School of Medicine, Kobe University, Kobe, Japan
| | - Yuka Kotozaki
- grid.411582.b0000 0001 1017 9540Division of Clinical research, Medical-Industry Translational Research Center, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Seishu Nakagawa
- grid.69566.3a0000 0001 2248 6943Department of Human Brain Science, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan ,grid.412755.00000 0001 2166 7427Division of Psychiatry, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Atsushi Sekiguchi
- grid.69566.3a0000 0001 2248 6943Division of Medical Neuroimaging Analysis, Department of Community Medical Supports, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan ,grid.419280.60000 0004 1763 8916Department of Behavioral Medicine, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Kunio Iizuka
- grid.69566.3a0000 0001 2248 6943Department of Psychiatry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Sugiko Hanawa
- grid.69566.3a0000 0001 2248 6943Department of Human Brain Science, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | | | - Carlos Makoto Miyauchi
- grid.69566.3a0000 0001 2248 6943Department of Advanced Brain Science, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Kohei Sakaki
- grid.69566.3a0000 0001 2248 6943Department of Advanced Brain Science, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Takayuki Nozawa
- grid.32197.3e0000 0001 2179 2105Research Institute for the Earth Inclusive Sensing, Tokyo Institute of Technology, Tokyo, Japan
| | - Shigeyuki Ikeda
- grid.69566.3a0000 0001 2248 6943Department of Ubiquitous Sensing, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Susum Yokota
- grid.177174.30000 0001 2242 4849Division for Experimental Natural Science, Faculty of Arts and Science, Kyushu University, Fukuoka, Japan
| | - Magistro Daniele
- grid.12361.370000 0001 0727 0669Department of Sport Science, School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Yuko Sassa
- grid.69566.3a0000 0001 2248 6943Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Ryuta Kawashima
- grid.69566.3a0000 0001 2248 6943Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan ,grid.69566.3a0000 0001 2248 6943Department of Advanced Brain Science, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan ,grid.69566.3a0000 0001 2248 6943Department of Human Brain Science, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
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6
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Lin LF, Xie J, Sánchez OF, Bryan C, Freeman JL, Yuan C. Low dose lead exposure induces alterations on heterochromatin hallmarks persisting through SH-SY5Y cell differentiation. CHEMOSPHERE 2021; 264:128486. [PMID: 33032221 DOI: 10.1016/j.chemosphere.2020.128486] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/28/2020] [Accepted: 09/28/2020] [Indexed: 06/11/2023]
Abstract
Lead (Pb) is a commonly found heavy metal due to its historical applications. Recent studies have associated early-life Pb exposure with the onset of various neurodegenerative disease. The molecular mechanisms of Pb conferring long-term neurotoxicity, however, is yet to be elucidated. In this study, we explored the persistency of alteration in epigenetic marks that arise from exposure to low dose of Pb using a combination of image-based and gene expression analysis. Using SH-SY5Y as a model cell line, we observed significant alterations in global 5-methycytosine (5 mC) and histone 3 lysine 27 tri-methylation (H3K27me3) and histone 3 lysine 9 tri-methylation (H3K9me3) levels in a dose-dependent manner immediately after Pb exposure. The changes are partially associated with alterations in epigenetic enzyme expression levels. Long term culturing (14 days) after cease of exposure revealed persistent changes in 5 mC, partial recovery in H3K9me3 and overcompensation in H3K27me3 levels. The observed alterations in H3K9me3 and H3K27me3 are reversed after neuronal differentiation, while reduction in 5 mC levels are amplified with significant changes in patterns as identified via texture clustering analysis. Moreover, correlation analysis demonstrates a strong positive correlation between trends of 5 mC alteration after differentiation and neuronal morphology. Collectively, our results suggest that exposure to low dose of Pb prior to differentiation can result in persistent epigenome alterations that can potentially be responsible for the observed phenotypic changes. Our work reveals that Pb induced changes in epigenetic repressive marks can persist through neuron differentiation, which provides a plausible mechanism underlying long-term neurotoxicity associated with developmental Pb-exposure.
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Affiliation(s)
- Li F Lin
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Junkai Xie
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Oscar F Sánchez
- Department of Nutrition and Biochemistry, Pontificia Universidad Javeriana, Bogotá, 110231, Colombia
| | - Chris Bryan
- Department of Statistics, Purdue University, West Lafayette, IN, 47907, USA
| | - Jennifer L Freeman
- School of Health Sciences, Purdue University, West Lafayette, IN, 47907, USA; Purdue University Center for Cancer Research, West Lafayette, IN, 47907, USA
| | - Chongli Yuan
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, 47907, USA; Purdue University Center for Cancer Research, West Lafayette, IN, 47907, USA.
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7
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Naffaa V, Laprévote O, Schang AL. Effects of endocrine disrupting chemicals on myelin development and diseases. Neurotoxicology 2020; 83:51-68. [PMID: 33352275 DOI: 10.1016/j.neuro.2020.12.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/10/2020] [Accepted: 12/16/2020] [Indexed: 12/14/2022]
Abstract
In the central and peripheral nervous systems, myelin is essential for efficient conduction of action potentials. During development, oligodendrocytes and Schwann cells differentiate and ensure axon myelination, and disruption of these processes can contribute to neurodevelopmental disorders. In adults, demyelination can lead to important disabilities, and recovery capacities by remyelination often decrease with disease progression. Among environmental chemical pollutants, endocrine disrupting chemicals (EDCs) are of major concern for human health and are notably suspected to participate in neurodevelopmental and neurodegenerative diseases. In this review, we have combined the current knowledge on EDCs impacts on myelin including several persistent organic pollutants, bisphenol A, triclosan, heavy metals, pesticides, and nicotine. Besides, we presented several other endocrine modulators, including pharmaceuticals and the phytoestrogen genistein, some of which are candidates for treating demyelinating conditions but could also be deleterious as contaminants. The direct impacts of EDCs on myelinating cells were considered as well as their indirect consequences on myelin, particularly on immune mechanisms associated with demyelinating conditions. More studies are needed to describe the effects of these compounds and to further understand the underlying mechanisms in relation to the potential for endocrine disruption.
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Affiliation(s)
- Vanessa Naffaa
- Université de Paris, UMR 8038 (CiTCoM), CNRS, Faculté de Pharmacie de Paris, 4 avenue de l'Observatoire, 75006 Paris, France.
| | - Olivier Laprévote
- Université de Paris, UMR 8038 (CiTCoM), CNRS, Faculté de Pharmacie de Paris, 4 avenue de l'Observatoire, 75006 Paris, France; Hôpital Européen Georges Pompidou, AP-HP, Service de Biochimie, 20 rue Leblanc, 75015 Paris, France.
| | - Anne-Laure Schang
- Université de Paris, UMR 1153 (CRESS), Faculté de Pharmacie de Paris, 4 avenue de l'Observatoire, 75006 Paris, France.
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8
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Abstract
Millions of Americans now entering midlife and old age were exposed to high levels of lead, a neurotoxin, as children. Evidence from animal-model and human observational studies suggest that childhood lead exposure may raise the risk of adult neurodegenerative disease, particularly dementia, through a variety of possible mechanisms including epigenetic modification, delayed cardiovascular and kidney disease, direct degenerative CNS injury from lead remobilized from bone, and lowered neural and cognitive reserve. Within the next ten years, the generation of children with the highest historical lead exposures, those born in the 1960s, 1970s, and 1980s, will begin to enter the age at which dementia symptoms tend to emerge. Many will also enter the age in which lead stored in the skeleton may be remobilized at greater rates, particularly for women entering menopause and men and women experiencing osteoporosis. Should childhood lead exposure prove pro-degenerative, the next twenty years will provide the last opportunities for possible early intervention to forestall greater degenerative disease burden across the aging lead-exposed population. More evidence is needed now to characterize the nature and magnitude of the degenerative risks facing adults exposed to lead as children and to identify interventions to limit long-term harm.
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Affiliation(s)
- Aaron Reuben
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
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9
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Thomason ME, Hect JL, Rauh VA, Trentacosta C, Wheelock MD, Eggebrecht AT, Espinoza-Heredia C, Burt SA. Prenatal lead exposure impacts cross-hemispheric and long-range connectivity in the human fetal brain. Neuroimage 2019; 191:186-192. [PMID: 30739062 PMCID: PMC6451829 DOI: 10.1016/j.neuroimage.2019.02.017] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 02/05/2019] [Accepted: 02/06/2019] [Indexed: 01/21/2023] Open
Abstract
Lead represents a highly prevalent metal toxicant with potential to alter human biology in lasting ways. A population segment that is particularly vulnerable to the negative consequences of lead exposure is the human fetus, as exposure events occurring before birth are linked to varied and long-ranging negative health and behavioral outcomes. An area that has yet to be addressed is the potential that lead exposure during pregnancy alters brain development even before an individual is born. Here, we combine prenatal lead exposure information extracted from newborn bloodspots with the human fetal brain functional MRI data to assess whether neural network connectivity differs between lead-exposed and lead-naïve fetuses. We found that neural connectivity patterns differed in lead-exposed and comparison groups such that fetuses that were not exposed demonstrated stronger age-related increases in cross-hemispheric connectivity, while the lead-exposed group demonstrated stronger age-related increases in posterior cingulate cortex (PCC) to lateral prefrontal cortex (PFC) connectivity. These are the first results to demonstrate metal toxicant-related alterations in human fetal neural connectivity. Remarkably, the findings point to alterations in systems that support higher-order cognitive and regulatory functions. Objectives for future work are to replicate these results in larger samples and to test the possibility that these alterations may account for significant variation in future child cognitive and behavioral outcomes.
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Affiliation(s)
- Moriah E Thomason
- Department of Child and Adolescent Psychiatry, New York University Medical Center, New York, USA; Department of Population Health, New York University Medical Center, New York, NY, USA; Institute for Social Research, University of Michigan, Ann Arbor, MI, USA.
| | - Jasmine L Hect
- Department of Psychology, Wayne State University, Detroit, MI, USA
| | - Virginia A Rauh
- The Heilbrunn Department of Population & Family Health, Columbia University Medical Center, New York, NY, USA
| | | | - Muriah D Wheelock
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO, USA
| | - Adam T Eggebrecht
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, MO, USA
| | - Claudia Espinoza-Heredia
- Department of Child and Adolescent Psychiatry, New York University Medical Center, New York, USA
| | - S Alexandra Burt
- Department of Psychology, Michigan State University, East Lansing, MI, USA
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10
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Sachana M, Rolaki A, Bal-Price A. Development of the Adverse Outcome Pathway (AOP): Chronic binding of antagonist to N-methyl-d-aspartate receptors (NMDARs) during brain development induces impairment of learning and memory abilities of children. Toxicol Appl Pharmacol 2018; 354:153-175. [PMID: 29524501 PMCID: PMC6095943 DOI: 10.1016/j.taap.2018.02.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 02/26/2018] [Accepted: 02/28/2018] [Indexed: 01/06/2023]
Abstract
The Adverse Outcome Pathways (AOPs) are designed to provide mechanistic understanding of complex biological systems and pathways of toxicity that result in adverse outcomes (AOs) relevant to regulatory endpoints. AOP concept captures in a structured way the causal relationships resulting from initial chemical interaction with biological target(s) (molecular initiating event) to an AO manifested in individual organisms and/or populations through a sequential series of key events (KEs), which are cellular, anatomical and/or functional changes in biological processes. An AOP provides the mechanistic detail required to support chemical safety assessment, the development of alternative methods and the implementation of an integrated testing strategy. An example of the AOP relevant to developmental neurotoxicity (DNT) is described here following the requirements of information defined by the OECD Users' Handbook Supplement to the Guidance Document for developing and assessing AOPs. In this AOP, the binding of an antagonist to glutamate receptor N-methyl-d-aspartate (NMDAR) receptor is defined as MIE. This MIE triggers a cascade of cellular KEs including reduction of intracellular calcium levels, reduction of brain derived neurotrophic factor release, neuronal cell death, decreased glutamate presynaptic release and aberrant dendritic morphology. At organ level, the above mentioned KEs lead to decreased synaptogenesis and decreased neuronal network formation and function causing learning and memory deficit at organism level, which is defined as the AO. There are in vitro, in vivo and epidemiological data that support the described KEs and their causative relationships rendering this AOP relevant to DNT evaluation in the context of regulatory purposes.
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Affiliation(s)
| | | | - Anna Bal-Price
- European Commission, Joint Research Centre, Ispra, Italy.
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11
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Sachana M, Rolaki A, Bal-Price A. Development of the Adverse Outcome Pathway (AOP): Chronic binding of antagonist to N-methyl-d-aspartate receptors (NMDARs) during brain development induces impairment of learning and memory abilities of children. Toxicol Appl Pharmacol 2018; 354:153-175. [PMID: 29524501 DOI: 10.1787/5jlsqs5hcrmq-en] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 02/26/2018] [Accepted: 02/28/2018] [Indexed: 05/20/2023]
Abstract
The Adverse Outcome Pathways (AOPs) are designed to provide mechanistic understanding of complex biological systems and pathways of toxicity that result in adverse outcomes (AOs) relevant to regulatory endpoints. AOP concept captures in a structured way the causal relationships resulting from initial chemical interaction with biological target(s) (molecular initiating event) to an AO manifested in individual organisms and/or populations through a sequential series of key events (KEs), which are cellular, anatomical and/or functional changes in biological processes. An AOP provides the mechanistic detail required to support chemical safety assessment, the development of alternative methods and the implementation of an integrated testing strategy. An example of the AOP relevant to developmental neurotoxicity (DNT) is described here following the requirements of information defined by the OECD Users' Handbook Supplement to the Guidance Document for developing and assessing AOPs. In this AOP, the binding of an antagonist to glutamate receptor N-methyl-d-aspartate (NMDAR) receptor is defined as MIE. This MIE triggers a cascade of cellular KEs including reduction of intracellular calcium levels, reduction of brain derived neurotrophic factor release, neuronal cell death, decreased glutamate presynaptic release and aberrant dendritic morphology. At organ level, the above mentioned KEs lead to decreased synaptogenesis and decreased neuronal network formation and function causing learning and memory deficit at organism level, which is defined as the AO. There are in vitro, in vivo and epidemiological data that support the described KEs and their causative relationships rendering this AOP relevant to DNT evaluation in the context of regulatory purposes.
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Affiliation(s)
| | | | - Anna Bal-Price
- European Commission, Joint Research Centre, Ispra, Italy.
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12
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Beckwith TJ, Dietrich KN, Wright JP, Altaye M, Cecil KM. Reduced regional volumes associated with total psychopathy scores in an adult population with childhood lead exposure. Neurotoxicology 2018; 67:1-26. [PMID: 29634994 PMCID: PMC6054826 DOI: 10.1016/j.neuro.2018.04.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 04/03/2018] [Accepted: 04/04/2018] [Indexed: 01/05/2023]
Abstract
Childhood lead exposure has been correlated to acts of delinquency and criminal behavior; however, little research has been conducted to examine its potential long term influence on behavioral factors such as personality, specifically psychopathic personality. Neuroimaging studies have demonstrated that the effects of childhood lead exposure persist into adulthood, with structural abnormalities found in gray and white matter regions involved in behavioral decision making. The current study examined whether measurements of adult psychopathy were associated with neuroanatomical differences in structural brain volumes for a longitudinal cohort with measured childhood lead exposure. We hypothesized that increased total psychopathy scores and increased blood lead concentration at 78 months of age (PbB78) would be inversely associated with volumetric measures of gray and white matter brain structures responsible for executive and emotional processing. Analyses did not display a direct effect between total psychopathy score and gray matter volume; however, reduced white matter volume in the cerebellum and brain stem in relation to increased total psychopathy scores was observed. An interaction between sex and total psychopathy score was also detected. Females displayed increased gray matter volume in the frontal, temporal, and parietal lobes associated with increased total psychopathy score, but did not display any white matter volume differences. Males primarily displayed reductions in frontal gray and white matter brain volume in relation to increased total psychopathy scores. Additionally, reduced gray and white matter volume was associated with increased blood lead levels in the frontal lobes; reduced white matter volume was also observed in the parietal and temporal lobes. Females demonstrated gray and white matter volume loss associated with increased PbB78 values in the right temporal lobe, as well as reduced gray matter volume in the frontal lobe. Males displayed reduced white matter volumes associated with increased PbB78 values in the frontal, temporal, and parietal lobes. Comparison of the two primary models revealed a volumetric decrease in the white matter of the left prefrontal cortex associated with increased total psychopathy scores and increased blood lead concentration in males. The results of this study suggested that increased psychopathy scores in this cohort may be attributable to the neuroanatomical abnormalities observed and that childhood lead exposure may be influential to these outcomes.
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Affiliation(s)
- Travis J Beckwith
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.
| | - Kim N Dietrich
- Department of Environmental Health, Division of Epidemiology and Biostatistics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - John P Wright
- School of Criminal Justice, University of Cincinnati, Cincinnati, OH, United States
| | - Mekibib Altaye
- Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Kim M Cecil
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States; Department of Environmental Health, Division of Epidemiology and Biostatistics, University of Cincinnati College of Medicine, Cincinnati, OH, United States; Department of Radiology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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13
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Nkomo P, Naicker N, Mathee A, Galpin J, Richter LM, Norris SA. The association between environmental lead exposure with aggressive behavior, and dimensionality of direct and indirect aggression during mid-adolescence: Birth to Twenty Plus cohort. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 612:472-479. [PMID: 28865264 DOI: 10.1016/j.scitotenv.2017.08.138] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 07/28/2017] [Accepted: 08/14/2017] [Indexed: 06/07/2023]
Abstract
Chronic lead exposure is associated with neurological ill-health including anti-social behavior such as aggressive behavior. The main aim of this study was to examine the association between lead exposure at 13years old and dimensions of aggressive behavior during mid-adolescence. The study sample included 508 males and 578 females in mid-adolescence (age 14 to 15years) from the Birth to Twenty Plus cohort in Johannesburg, South Africa. Blood samples collected at age 13years were used to measure blood lead levels. Seventeen items characterizing aggression from the Youth Self Report questionnaire were used to examine aggressive behavior. Principal Component Analysis was used to derive composite variables from the original data for aggressive behavior; and data were examined for an association between blood lead levels and dimensionality of direct and indirect aggression and disobedience during mid-adolescence. We also examined the dimensions of aggression during mid-adolescence in relation to gender and socio-demographic factors. Blood lead levels ranged from 1 to 28.1μg/dL. Seventy two percent of males and 47.7% of females in the study had blood lead levels ≥5μg/dL. There was a positive association between elevated blood lead levels and direct aggression (p<0.05). Being male was positively associated with direct aggression (p<0.001) but, negatively associated with indirect aggression (p<0.001). Maternal education and age at birth were negatively associated with direct aggression during mid-adolescence. The significant association between elevated blood lead levels and direct aggressive behavior observed in this study may shed light on a possible environmental toxicological contribution to aggressive behavior in South African youth; and most importantly the type of aggressive behavior associated to lead exposure.
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Affiliation(s)
- Palesa Nkomo
- Environment & Health Research Unit, Medical Research Council (MRC), South Africa; MRC/Wits Developmental Pathways for Health Research Unit, Department of Paediatrics, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - Nisha Naicker
- Environment & Health Research Unit, Medical Research Council (MRC), South Africa; School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Environmental Health Department, Faculty of Health Sciences, University of Johannesburg, South Africa.
| | - Angela Mathee
- Environment & Health Research Unit, Medical Research Council (MRC), South Africa; School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Environmental Health Department, Faculty of Health Sciences, University of Johannesburg, South Africa.
| | - Jacky Galpin
- School of Statistics, The Witwatersrand University, Johannesburg, South Africa.
| | - Linda M Richter
- MRC/Wits Developmental Pathways for Health Research Unit, Department of Paediatrics, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; DST-NRF Centre of Excellence in Human Development, University of the Witwatersrand, Johannesburg, South Africa.
| | - Shane A Norris
- MRC/Wits Developmental Pathways for Health Research Unit, Department of Paediatrics, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; DST-NRF Centre of Excellence in Human Development, University of the Witwatersrand, Johannesburg, South Africa.
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The Neurodevelopmental Toxicity of Lead: History, Epidemiology, and Public Health Implications. LINKING ENVIRONMENTAL EXPOSURE TO NEURODEVELOPMENTAL DISORDERS 2018. [DOI: 10.1016/bs.ant.2018.03.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Nkomo P, Mathee A, Naicker N, Galpin J, Richter LM, Norris SA. The association between elevated blood lead levels and violent behavior during late adolescence: The South African Birth to Twenty Plus cohort. ENVIRONMENT INTERNATIONAL 2017; 109:136-145. [PMID: 28916132 DOI: 10.1016/j.envint.2017.09.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 09/01/2017] [Accepted: 09/02/2017] [Indexed: 06/07/2023]
Abstract
Epidemiological studies have shown the adverse neuro-behavioral health effects of lead exposure among children, in particular. However, there is lack evidence in this regard from developing countries. The main aim of this study was to assess the association between blood lead levels (BLLs) during early adolescence and violent behavior in late adolescence. Our study sample from the Birth to Twenty Plus cohort in Soweto-Johannesburg, South Africa included 1332 study participants (684 females). BLLs were measured using blood samples collected at age 13years. Violent behavior was evaluated using data collected at ages 15 to 16years using the Youth Self Report questionnaire. First, bivariate analysis was used to examine data for an association between lead exposure in early adolescence and violent behavior items during late adolescence. Principal Component Analysis (PCA) was used for dimensionality reduction and six violent behavior components were derived. Data were further analyzed for an association between BLLs at age 13years and violent behavior using PCA derived components; to determine the specific type(s) of violent behavior associated with lead exposure. Median whole BLLs were 5.6μg/dL (p<0.001). Seventy five percent of males and 50% of females had BLLs≥5μg/dL. BLLs ranging from 5 to 9.99μg/dL were associated with physical violence (p=0.03) and BLLs≥10μg/dL were associated physical violence and fighting (p=0.02 and p=0.01, respectively). When data were analyzed using continuous BLLs physical violence was associated with lead exposure (p<0.0001). Furthermore, males were more likely to be involved in violence using a weapon (p=0.01), physical violence (p<0.0001), and robbing others (p<0.05) compared to females. The results from this study show the severe nature of violent behavior in late adolescence associated with childhood lead exposure. They highlight the urgent need for preventive measures against lead exposure among children in low or middle income countries such as South Africa.
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Affiliation(s)
- Palesa Nkomo
- Environment & Health Research Unit, Medical Research Council, South Africa; MRC/Wits Developmental Pathways for Health Research Unit, Department of Paediatrics, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - Angela Mathee
- Environment & Health Research Unit, Medical Research Council, South Africa; School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Environmental Health Department, Faculty of Health Sciences, University of Johannesburg, South Africa.
| | - Nisha Naicker
- Environment & Health Research Unit, Medical Research Council, South Africa; School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Environmental Health Department, Faculty of Health Sciences, University of Johannesburg, South Africa.
| | - Jacky Galpin
- School of Statistics and Actuarial Science, University of the Witwatersrand, Johannesburg, South Africa.
| | - Linda M Richter
- DST-NRF Centre of Excellence in Human Development, University of the Witwatersrand, Johannesburg, South Africa.
| | - Shane A Norris
- MRC/Wits Developmental Pathways for Health Research Unit, Department of Paediatrics, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; DST-NRF Centre of Excellence in Human Development, University of the Witwatersrand, Johannesburg, South Africa.
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Yu SY, Paul S, Hwang SY. Application of the emerging technologies in toxicogenomics: An overview. BIOCHIP JOURNAL 2016. [DOI: 10.1007/s13206-016-0405-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Biofluid metabotyping of occupationally exposed subjects to air pollution demonstrates high oxidative stress and deregulated amino acid metabolism. Sci Rep 2016; 6:35972. [PMID: 27767182 PMCID: PMC5073280 DOI: 10.1038/srep35972] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 10/10/2016] [Indexed: 12/31/2022] Open
Abstract
Occupational exposure to air pollution induces oxidative stress and prolonged exposure increases susceptibility to cardiovascular and respiratory diseases in several working groups. Biofluid of these subjects may reflect perturbed metabolic phenotypes. In this study we carried out a comparative molecular profiling study using parallel biofluids collected from subjects (n = 85) belonging to auto rickshaw drivers (ARD), traffic cops (TC) and office workers (OW). Higher levels of oxidative stress and inflammation markers in serum of ARD subjects were observed as compared to OW and TC. Uni and multivariate analyses of metabolites identified in urine by 1H NMR revealed 11 deregulated molecules in ARD subjects and involved in phenylalanine, histidine, arginine and proline metabolism. Despite contribution of confounding factors like exposure period, dietary factors including smoking and alcohol status, our results demonstrate existence of exposure specific metabotypes in biofluids of ARD, OW and TC groups. Monitoring serum oxidative stress and inflammation markers and urine metabolites by NMR may be useful to characterize perturbed metabolic phenotypes in populations exposed to urban traffic air pollution.
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Abstract
Metabolic imaging enhances understanding of disease metabolisms and holds great potential as a measurement tool for evaluating disease prognosis and treatment effectiveness. Advancement of techniques, such as magnetic resonance spectroscopy, positron emission tomography, and mass spectrometry, allows for improved accuracy for quantification of metabolites and present unique possibilities for use in clinic. This article reviews and discusses literature reports of metabolic imaging in humans published since 2010 according to disease type, including cancer, degenerative disorders, psychiatric disorders, and others, as well as the current application of the various related techniques.
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Affiliation(s)
- Taylor L. Fuss
- Departments of Radiology and Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, 02114 USA
| | - Leo L. Cheng
- Departments of Radiology and Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, 02114 USA
- Corresponding Author: Leo L. Cheng, PhD, 149 13 Street, CNY-6, Charlestown, MA 02129, Ph.617-724-6593, Fax.617-726-5684,
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Eid A, Zawia N. Consequences of lead exposure, and it’s emerging role as an epigenetic modifier in the aging brain. Neurotoxicology 2016; 56:254-261. [DOI: 10.1016/j.neuro.2016.04.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 04/06/2016] [Accepted: 04/07/2016] [Indexed: 12/14/2022]
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Rogers JT, Venkataramani V, Washburn C, Liu Y, Tummala V, Jiang H, Smith A, Cahill CM. A role for amyloid precursor protein translation to restore iron homeostasis and ameliorate lead (Pb) neurotoxicity. J Neurochem 2016; 138:479-94. [PMID: 27206843 DOI: 10.1111/jnc.13671] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 03/31/2016] [Accepted: 04/08/2016] [Indexed: 12/30/2022]
Abstract
Iron supplementation ameliorates the neurotoxicity of the environmental contaminant lead (Pb); however, the mechanism remains undefined. Iron is an essential nutrient but high levels are toxic due to the catalytic generation of destructive hydroxyl radicals. Using human neuroblastoma SH-SY5Y cells to model human neurons, we investigated the effect of Pb on proteins of iron homeostasis: the Alzheimer's amyloid precursor protein (APP), which stabilizes the iron exporter ferroportin 1; and, the heavy subunit of the iron-storage protein, ferritin (FTH). Lead (Pb(II) and Pb(IV) inhibited APP translation and raised cytosolic iron(II). Lead also increased iron regulatory protein-1 binding to the cognate 5'untranslated region-specific iron-responsive element (IRE) of APP and FTH mRNAs. Concurrent iron treatment rescued cells from Pb toxicity by specifically restoring APP synthesis, i.e. levels of the APP-related protein, APLP-2, were unchanged. Significantly, iron/IRE-independent over-expression of APP695 protected SH-SY5Y cells from Pb toxicity, demonstrating that APP plays a key role in maintaining safe levels of intracellular iron. Overall, our data support a model of neurotoxicity where Pb enhances iron regulatory protein/IRE-mediated repression of APP and FTH translation. We propose novel treatment options for Pb poisoning to include chelators and the use of small molecules to maintain APP and FTH translation. We propose the following cascade for Lead (Pb) toxicity to neurons; by targeting the interaction between Iron regulatory protein-1 and Iron-responsive elements, Pb caused translational repression of proteins that control intracellular iron homeostasis, including the Alzheimer's amyloid precursor protein (APP) that stabilizes the iron exporter ferroportin, and the ferroxidase heavy subunit of the iron-storage protein, ferritin. When unregulated, IRE-independent over-expression of APP695 protected SH-SY5Y neurons from Pb toxicity. There is a novel and key role for APP in maintaining safe levels of intracellular iron pertinent to lead toxicity.
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Affiliation(s)
- Jack T Rogers
- Neurochemistry Laboratory, Department of Psychiatry-Neuroscience, Massachusetts General Hospital (East), Harvard Medical School, Charlestown, Massachusetts, USA
| | - Vivek Venkataramani
- Department of Hematology and Medical Oncology, University Medical Center, Goettingen, Germany
| | - Cecilia Washburn
- Neurochemistry Laboratory, Department of Psychiatry-Neuroscience, Massachusetts General Hospital (East), Harvard Medical School, Charlestown, Massachusetts, USA
| | - Yanyan Liu
- Neurochemistry Laboratory, Department of Psychiatry-Neuroscience, Massachusetts General Hospital (East), Harvard Medical School, Charlestown, Massachusetts, USA
| | - Vinusha Tummala
- Neurochemistry Laboratory, Department of Psychiatry-Neuroscience, Massachusetts General Hospital (East), Harvard Medical School, Charlestown, Massachusetts, USA
| | - Hong Jiang
- State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China
| | - Ann Smith
- School of Biological Sciences, University of Missouri-K.C., Kansas City, Missouri, USA
| | - Catherine M Cahill
- Neurochemistry Laboratory, Department of Psychiatry-Neuroscience, Massachusetts General Hospital (East), Harvard Medical School, Charlestown, Massachusetts, USA
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Rauh VA, Margolis AE. Research Review: Environmental exposures, neurodevelopment, and child mental health - new paradigms for the study of brain and behavioral effects. J Child Psychol Psychiatry 2016; 57:775-93. [PMID: 26987761 PMCID: PMC4914412 DOI: 10.1111/jcpp.12537] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/05/2016] [Indexed: 12/23/2022]
Abstract
BACKGROUND Environmental exposures play a critical role in the genesis of some child mental health problems. METHODS We open with a discussion of children's vulnerability to neurotoxic substances, changes in the distribution of toxic exposures, and cooccurrence of social and physical exposures. We address trends in prevalence of mental health disorders, and approaches to the definition of disorders that are sensitive to the subtle effects of toxic exposures. We suggest broadening outcomes to include dimensional measures of autism spectrum disorders, attention-deficit hyperactivity disorder, and child learning capacity, as well as direct assessment of brain function. FINDINGS We consider the impact of two important exposures on children's mental health: lead and pesticides. We argue that longitudinal research designs may capture the cascading effects of exposures across biological systems and the full-range of neuropsychological endpoints. Neuroimaging is a valuable tool for observing brain maturation under varying environmental conditions. A dimensional approach to measurement may be sensitive to subtle subclinical toxic effects, permitting the development of exposure-related profiles and testing of complex functional relationships between brain and behavior. Questions about the neurotoxic effects of chemicals become more pressing when viewed through the lens of environmental justice. CONCLUSIONS Reduction in the burden of child mental health disorders will require longitudinal study of neurotoxic exposures, incorporating dimensional approaches to outcome assessment, and measures of brain function. Research that seeks to identify links between toxic exposures and mental health outcomes has enormous public health and societal value.
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Affiliation(s)
- Virginia A Rauh
- Heilbrunn Department of Population and Family Health, Mailman School of Public Health, Columbia University, New York, NY, USA
- Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Amy E Margolis
- Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, New York, NY, USA
- Department of Child and Adolescent Psychiatry, Columbia University, New York, NY, USA
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Nigg JT, Elmore AL, Natarajan N, Friderici KH, Nikolas MA. Variation in an Iron Metabolism Gene Moderates the Association Between Blood Lead Levels and Attention-Deficit/Hyperactivity Disorder in Children. Psychol Sci 2015; 27:257-69. [PMID: 26710823 DOI: 10.1177/0956797615618365] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 10/29/2015] [Indexed: 12/12/2022] Open
Abstract
Although attention-deficit/hyperactivity disorder (ADHD) is a heritable neurodevelopmental condition, there is also considerable scientific and public interest in environmental modulators of its etiology. Exposure to neurotoxins is one potential source of perturbation of neural, and hence psychological, development. Exposure to lead in particular has been widely investigated and is correlated with neurodevelopmental outcomes, including ADHD. To investigate whether this effect is likely to be causal, we used a Mendelian randomization design with a functional gene variant. In a case-control study, we examined the association between ADHD symptoms in children and blood lead level as moderated by variants in the hemochromatosis (HFE) gene. The HFE gene regulates iron uptake and secondarily modulates lead metabolism. Statistical moderation was observed: The magnitude of the association of blood lead with symptoms of ADHD was altered by functional HFE genotype, which is consistent with a causal hypothesis.
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Affiliation(s)
- Joel T Nigg
- Department of Psychiatry, Oregon Health & Science University Department of Behavioral Neuroscience, Oregon Health & Science University
| | - Alexis L Elmore
- Department of Psychological & Brain Sciences, University of Iowa
| | - Neil Natarajan
- Department of Psychiatry, Oregon Health & Science University
| | - Karen H Friderici
- Department of Microbiology and Molecular Genetics, Michigan State University
| | - Molly A Nikolas
- Department of Microbiology and Molecular Genetics, Michigan State University
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Occupation and the risk of chronic toxic leukoencephalopathy. HANDBOOK OF CLINICAL NEUROLOGY 2015; 131:73-91. [PMID: 26563784 DOI: 10.1016/b978-0-444-62627-1.00006-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Among the hundreds of environmental insults capable of inducing nervous system injury, a small number can produce clinically significant damage to the brain white matter. The use of magnetic resonance imaging (MRI) in affected individuals has greatly illuminated this previously obscure area of neurotoxicology. Toxic leukoencephalopathy has acute and chronic forms, in both of which cognitive dysfunction is the major clinical manifestation. Chronic toxic leukoencephalopathy (CTL) has been most thoroughly described in individuals with intense and prolonged exposure to leukotoxins, but the consequences of lesser degrees of exposure are not well understood. Rare cases of CTL have been reported in workers exposed to culpable leukotoxins, but study of this syndrome is hindered by many confounds such as uncertain level of toxin exposure, the presence of multiple toxins, vague dose-response relationship, comorbid medical or neurologic disorders, psychiatric illness, and legal issues. The risk of CTL in workers is low, although it is not possible to determine quantitative risk estimates. More knowledge can be expected with the application of advanced MRI techniques to the assessment of workers who may have been exposed to known or potential leukotoxins. Preventive measures for avoiding workplace CTL will be informed by clinical assessment involving the use of advanced neuroimaging and neuropsychologic evaluation in combination with accurate measurement of leukotoxin exposure.
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Lindquist DM, Beckwith T, Cecil KM, Sánchez-Martín FJ, Landero-Figueroa J, Puga A. Prenatal and early postnatal lead exposure in mice: neuroimaging findings. Quant Imaging Med Surg 2015; 5:511-8. [PMID: 26435914 DOI: 10.3978/j.issn.2223-4292.2015.07.01] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND Childhood lead exposure has been linked to adult gray matter loss accompanied by changes in myelination and neurochemistry noninvasively revealed by magnetic resonance imaging (MRI) methods. However, the extent, duration and timing of lead exposure required to produce such imaging changes in humans are difficult to ascertain. METHODS To determine if such changes are related to early exposure to low levels of lead, we treated mouse dams with 0, 3, or 30 ppm of lead acetate in drinking water for 2 months prior to mating through gestation until weaning of the offspring at post-natal day 21. Two male and two female pups from each litter were imaged at post-natal day 60. Volumetric, diffusion tensor imaging and magnetic resonance spectroscopy (MRS) measurements were obtained using a seven Tesla Bruker animal MRI scanner. RESULTS Postnatal blood lead levels were identical between groups at the time of imaging. No effects of lead exposure were detected in the volumetric or MRS data. Mean diffusivity in the hippocampus showed significant effects of lead exposure and gender. CONCLUSIONS These data suggest that low-level, gestational lead exposure in a mouse model produces minimal changes observed by MRI.
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Affiliation(s)
- Diana M Lindquist
- 1 Imaging Research Center, Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA ; 2 Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA ; 3 Metallomics Center of the Americas, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, USA
| | - Travis Beckwith
- 1 Imaging Research Center, Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA ; 2 Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA ; 3 Metallomics Center of the Americas, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, USA
| | - Kim M Cecil
- 1 Imaging Research Center, Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA ; 2 Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA ; 3 Metallomics Center of the Americas, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, USA
| | - Francisco Javier Sánchez-Martín
- 1 Imaging Research Center, Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA ; 2 Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA ; 3 Metallomics Center of the Americas, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, USA
| | - Julio Landero-Figueroa
- 1 Imaging Research Center, Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA ; 2 Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA ; 3 Metallomics Center of the Americas, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, USA
| | - Alvaro Puga
- 1 Imaging Research Center, Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA ; 2 Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA ; 3 Metallomics Center of the Americas, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, USA
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Goodman JE, Petito Boyce C, Sax SN, Beyer LA, Prueitt RL. Rethinking Meta-Analysis: Applications for Air Pollution Data and Beyond. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2015; 35:1017-39. [PMID: 25969128 PMCID: PMC4690509 DOI: 10.1111/risa.12405] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Meta-analyses offer a rigorous and transparent systematic framework for synthesizing data that can be used for a wide range of research areas, study designs, and data types. Both the outcome of meta-analyses and the meta-analysis process itself can yield useful insights for answering scientific questions and making policy decisions. Development of the National Ambient Air Quality Standards illustrates many potential applications of meta-analysis. These applications demonstrate the strengths and limitations of meta-analysis, issues that arise in various data realms, how meta-analysis design choices can influence interpretation of results, and how meta-analysis can be used to address bias and heterogeneity. Reviewing available data from a meta-analysis perspective can provide a useful framework and impetus for identifying and refining strategies for future research. Moreover, increased pervasiveness of a meta-analysis mindset-focusing on how the pieces of the research puzzle fit together-would benefit scientific research and data syntheses regardless of whether or not a quantitative meta-analysis is undertaken. While an individual meta-analysis can only synthesize studies addressing the same research question, the results of separate meta-analyses can be combined to address a question encompassing multiple data types. This observation applies to any scientific or policy area where information from a variety of disciplines must be considered to address a broader research question.
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26
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The Role of Heavy Metal Pollution in Neurobehavioral Disorders: a Focus on Autism. REVIEW JOURNAL OF AUTISM AND DEVELOPMENTAL DISORDERS 2014. [DOI: 10.1007/s40489-014-0028-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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27
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Searle AK, Baghurst PA, van Hooff M, Sawyer MG, Sim MR, Galletly C, Clark LS, McFarlane AC. Tracing the long-term legacy of childhood lead exposure: a review of three decades of the port Pirie cohort study. Neurotoxicology 2014; 43:46-56. [PMID: 24785378 DOI: 10.1016/j.neuro.2014.04.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 03/28/2014] [Accepted: 04/21/2014] [Indexed: 11/17/2022]
Abstract
Several prospective cohort studies have demonstrated that childhood lead levels show small but statistically significant adjusted associations with subsequent development in later childhood and adolescence. The Port Pirie Cohort study is one of the few prospective cohort studies to follow participants into adulthood. This paper reviews all childhood and adulthood findings of the Port Pirie Cohort study to date. Cohort members (initially, 723 infants born in/around the lead-smelting town of Port Pirie) showed a wide range of childhood blood lead levels, which peaked around 2 years old (M=21.3μg/dL, SD=1.2). At all childhood assessments, postnatal lead levels - particularly those reflecting cumulative exposure - showed small significant associations with outcomes including cognitive development, IQ, and mental health problems. While associations were substantially attenuated after adjusting for several childhood covariates, many remained statistically significant. Furthermore, average childhood blood lead showed small significant associations with some adult mental health problems for females, including anxiety problems and phobia, though associations only approached significance following covariate adjustment. Overall, there did not appear to be any age of greatest vulnerability or threshold of effect, and at all ages, females appeared more susceptible to lead-associated deficits. Together, these findings suggest that the associations between early childhood lead exposure and subsequent developmental outcomes may persist. However, as the magnitude of these effects was small, they are not discernible at the individual level, posing more of a population health concern. It appears that the combination of multiple early childhood factors best predicts later development. As such, minimising lead exposure in combination with improving other important early childhood factors such as parent-child interactions may be the best way to improve developmental outcomes.
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Affiliation(s)
- Amelia K Searle
- Centre for Traumatic Stress Studies, School of Population Health, University of Adelaide, South Australia 5000, Australia.
| | - Peter A Baghurst
- Discipline of Public Health, University of Adelaide, South Australia 5000, Australia; Discipline of Paediatrics, University of Adelaide, South Australia 5000, Australia
| | - Miranda van Hooff
- Centre for Traumatic Stress Studies, School of Population Health, University of Adelaide, South Australia 5000, Australia
| | - Michael G Sawyer
- Discipline of Paediatrics, University of Adelaide, South Australia 5000, Australia; Research and Evaluation Unit, Women's and Children's Health Network, South Australia 5000, Australia
| | - Malcolm R Sim
- Department of Epidemiology & Preventive Medicine, Monash University, Victoria 3004, Australia
| | - Cherrie Galletly
- Discipline of Psychiatry, University of Adelaide, South Australia 5000, Australia
| | - Levina S Clark
- Psychology Clinic, Flinders University, South Australia 5000, Australia
| | - Alexander C McFarlane
- Centre for Traumatic Stress Studies, School of Population Health, University of Adelaide, South Australia 5000, Australia
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Abstract
PURPOSE OF REVIEW The prevalence of childhood neurodevelopmental disorders has been increasing over the last several decades. Prenatal and early childhood exposure to environmental toxicants is increasingly recognized as contributing to the growing rate of neurodevelopmental disorders. Very little information is known about the mechanistic processes by which environmental chemicals alter brain development. We review the recent advances in brain imaging modalities and discuss their application in epidemiologic studies of prenatal and early childhood exposure to environmental toxicants. RECENT FINDINGS Neuroimaging techniques (volumetric and functional MRI, diffusor tensor imaging, and magnetic resonance spectroscopy) have opened unprecedented access to study the developing human brain. These techniques are noninvasive and free of ionization radiation making them suitable for research applications in children. Using these techniques, we now understand much about structural and functional patterns in the typically developing brain. This knowledge allows us to investigate how prenatal exposure to environmental toxicants may alter the typical developmental trajectory. SUMMARY MRI is a powerful tool that allows in-vivo visualization of brain structure and function. Used in epidemiologic studies of environmental exposure, it offers the promise to causally link exposure with behavioral and cognitive manifestations and ultimately to inform programs to reduce exposure and mitigate adverse effects of exposure.
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Influence of prenatal exposure to environmental pollutants on human cord blood levels of glutamate. Neurotoxicology 2013; 40:102-10. [PMID: 24361731 DOI: 10.1016/j.neuro.2013.12.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 12/09/2013] [Accepted: 12/10/2013] [Indexed: 11/21/2022]
Abstract
Some chemicals released into the environment, including mercury and some organochlorine compounds (OCs), are suspected to have a key role on subclinical brain dysfunction in childhood. Alteration of the glutamatergic system may be one mechanistic pathway. We aimed to determine whether mercury and seven OCs, including PCBs 138, 153, and 180, DDT and DDE, hexachlorobenzene (HCB), and beta-hexachlorocyclohexane (β-HCH) influence the cord levels of two excitatory amino acids, glutamate and aspartate. Second, we evaluated if this association was mediated by glutamate uptake measured in human placental membranes. The study sample included 40 newborns from a Spanish cohort selected according to cord mercury levels. We determined the content of both amino acids in cord blood samples by means of HPLC and assessed their associations with the contaminants using linear regression analyses, and the effect of the contaminants on glutamate uptake by means of [(3)H]-aspartate binding in human placenta samples. PCB138, β-HCH, and the sum of the three PCBs and seven OCs showed a significant negative association with glutamate levels (decrease of 51, 24, 56 and 54%, respectively, in glutamate levels for each 10-fold increase in the contaminant concentration). Mercury did not show a significant correlation neither with glutamate nor aspartate levels in cord blood, however a compensatory effect between T-Hg and both PCB138, and 4,4'-DDE was observed. The organo-metallic derivative methylmercury completely inhibited glutamate uptake in placenta while PCB138 and β-HCH partially inhibited it (IC50 values: 4.9±0.8 μM, 14.2±1.2 nM and 6.9±2.9 nM, respectively). We conclude that some environmental toxicants may alter the glutamate content in the umbilical cord blood, which might underlie alterations in human development.
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McFarlane AC, Searle AK, Van Hooff M, Baghurst PA, Sawyer MG, Galletly C, Sim MR, Clark LS. Prospective associations between childhood low-level lead exposure and adult mental health problems: The Port Pirie cohort study. Neurotoxicology 2013; 39:11-7. [DOI: 10.1016/j.neuro.2013.08.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 08/06/2013] [Accepted: 08/06/2013] [Indexed: 10/26/2022]
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Rai NK, Ashok A, Rai A, Tripathi S, Nagar GK, Mitra K, Bandyopadhyay S. Exposure to As, Cd and Pb-mixture impairs myelin and axon development in rat brain, optic nerve and retina. Toxicol Appl Pharmacol 2013; 273:242-58. [DOI: 10.1016/j.taap.2013.05.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 04/13/2013] [Accepted: 05/03/2013] [Indexed: 01/25/2023]
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Sánchez-Martín FJ, Fan Y, Lindquist DM, Xia Y, Puga A. Lead induces similar gene expression changes in brains of gestationally exposed adult mice and in neurons differentiated from mouse embryonic stem cells. PLoS One 2013; 8:e80558. [PMID: 24260418 PMCID: PMC3834098 DOI: 10.1371/journal.pone.0080558] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Accepted: 10/15/2013] [Indexed: 12/22/2022] Open
Abstract
Exposure to environmental toxicants during embryonic life causes changes in the expression of developmental genes that may last for a lifetime and adversely affect the exposed individual. Developmental exposure to lead (Pb), an ubiquitous environmental contaminant, causes deficits in cognitive functions and IQ, behavioral effects, and attention deficit hyperactivity disorder (ADHD). Long-term effects observed after early life exposure to Pb include reduction of gray matter, alteration of myelin structure, and increment of criminal behavior in adults. Despite growing research interest, the molecular mechanisms responsible for the effects of lead in the central nervous system are still largely unknown. To study the molecular changes due to Pb exposure during neurodevelopment, we exposed mice to Pb in utero and examined the expression of neural markers, neurotrophins, transcription factors and glutamate-related genes in hippocampus, cortex, and thalamus at postnatal day 60. We found that hippocampus was the area where gene expression changes due to Pb exposure were more pronounced. To recapitulate gestational Pb exposure in vitro, we differentiated mouse embryonic stem cells (ESC) into neurons and treated ESC-derived neurons with Pb for the length of the differentiation process. These neurons expressed the characteristic neuronal markers Tubb3, Syp, Gap43, Hud, Ngn1, Vglut1 (a marker of glutamatergic neurons), and all the glutamate receptor subunits, but not the glial marker Gafp. Importantly, several of the changes observed in Pb-exposed mouse brains in vivo were also observed in Pb-treated ESC-derived neurons, including those affecting expression of Ngn1, Bdnf exon IV, Grin1, Grin2D, Grik5, Gria4, and Grm6. We conclude that our ESC-derived model of toxicant exposure during neural differentiation promises to be a useful model to analyze mechanisms of neurotoxicity induced by Pb and other environmental agents.
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Affiliation(s)
- Francisco Javier Sánchez-Martín
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati, College of Medicine, Cincinnati, Ohio, United States of America
| | - Yunxia Fan
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati, College of Medicine, Cincinnati, Ohio, United States of America
| | - Diana M. Lindquist
- Cincinnati Children's Hospital Medical Center, Department of Radiology, Cincinnati, Ohio, United States of America
| | - Ying Xia
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati, College of Medicine, Cincinnati, Ohio, United States of America
| | - Alvaro Puga
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati, College of Medicine, Cincinnati, Ohio, United States of America
- * E-mail:
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Prenatal Exposures to Environmental Chemicals and Children's Neurodevelopment: An Update. Saf Health Work 2013; 4:1-11. [PMID: 23515885 PMCID: PMC3601292 DOI: 10.5491/shaw.2013.4.1.1] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/06/2013] [Accepted: 02/06/2013] [Indexed: 01/17/2023] Open
Abstract
This review surveys the recent literature on the neurodevelopmental impacts of chemical exposures during pregnancy. The review focuses primarily on chemicals of recent concern, including phthalates, bisphenol-A, polybrominated diphenyl ethers, and perfluorinated compounds, but also addresses chemicals with longer histories of investigation, including air pollutants, lead, methylmercury, manganese, arsenic, and organophosphate pesticides. For some chemicals of more recent concern, the available literature does not yet afford strong conclusions about neurodevelopment toxicity. In such cases, points of disagreement among studies are identified and suggestions provided for approaches to resolution of the inconsistencies, including greater standardization of methods for expressing exposure and assessing outcomes.
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Zahran S, Mielke HW, Weiler S, Hempel L, Berry KJ, Gonzales CR. Associations between standardized school performance tests and mixtures of Pb, Zn, Cd, Ni, Mn, Cu, Cr, Co, and V in community soils of New Orleans. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2012; 169:128-35. [PMID: 22705504 DOI: 10.1016/j.envpol.2012.05.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 05/09/2012] [Accepted: 05/12/2012] [Indexed: 05/06/2023]
Abstract
In New Orleans a strong inverse association was previously identified between community soil lead and 4th grade school performance. This study extends the association to zinc, cadmium, nickel, manganese, copper, chromium, cobalt, and vanadium in community soil and their comparative effects on 4th grade school performance. Adjusting for poverty, food security, racial composition, and teacher-student ratios, regression results show that soil metals variously reduce and compress student scores. Soil metals account for 22%-24% while food insecurity accounts for 29%-37% of variation in school performance. The impact on grade point averages were Ni > Co > Mn > Cu ~ Cr ~ Cd > Zn > Pb, but metals are mixtures in soils. The quantities of soil metal mixtures vary widely across the city with the largest totals in the inner city and smallest totals in the outer city. School grade point averages are lowest where the soil metal mixtures and food insecurity are highest.
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Affiliation(s)
- Sammy Zahran
- Department of Economics, Colorado State University, Fort Collins, CO 80523-1771, USA.
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Mielke HW, Zahran S. The urban rise and fall of air lead (Pb) and the latent surge and retreat of societal violence. ENVIRONMENT INTERNATIONAL 2012; 43:48-55. [PMID: 22484219 DOI: 10.1016/j.envint.2012.03.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 03/06/2012] [Accepted: 03/08/2012] [Indexed: 05/22/2023]
Abstract
We evaluate air Pb emissions and latent aggravated assault behavior at the scale of the city. We accomplish this by regressing annual Federal Bureau of Investigation aggravated assault rate records against the rise and fall of annual vehicle Pb emissions in Chicago (Illinois), Indianapolis (Indiana), Minneapolis (Minnesota), San Diego (California), Atlanta (Georgia), and New Orleans (Louisiana). Other things held equal, a 1% increase in tonnages of air Pb released 22 years prior raises the present period aggravated assault rate by 0.46% (95% CI, 0.28 to 0.64). Overall our model explains 90% of the variation in aggravated assault across the cities examined. In the case of New Orleans, 85% of temporal variation in the aggravated assault rate is explained by the annual rise and fall of air Pb (total=10,179 metric tons) released on the population of New Orleans 22 years earlier. For every metric ton of Pb released 22 years prior, a latent increase of 1.59 (95% CI, 1.36 to 1.83, p<0.001) aggravated assaults per 100,000 were reported. Vehicles consuming fuel containing Pb additives contributed much larger quantities of Pb dust than generally recognized. Our findings along with others predict that prevention of children's lead exposure from lead dust now will realize numerous societal benefits two decades into the future, including lower rates of aggravated assault.
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Affiliation(s)
- Howard W Mielke
- Department of Pharmacology, Tulane School of Medicine, New Orleans, LA 70112, USA.
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Boucher O, Burden MJ, Muckle G, Saint-Amour D, Ayotte P, Dewailly É, Nelson CA, Jacobson SW, Jacobson JL. Response inhibition and error monitoring during a visual go/no-go task in inuit children exposed to lead, polychlorinated biphenyls, and methylmercury. ENVIRONMENTAL HEALTH PERSPECTIVES 2012; 120:608-15. [PMID: 22142904 PMCID: PMC3339450 DOI: 10.1289/ehp.1103828] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 12/05/2011] [Indexed: 05/18/2023]
Abstract
BACKGROUND Lead (Pb) and polychlorinated biphenyls (PCBs) are neurotoxic contaminants that have been related to impairment in response inhibition. OBJECTIVES In this study we examined the neurophysiological correlates of the response inhibition deficits associated with these exposures, using event-related potentials (ERPs) in a sample of school-age Inuit children from Arctic Québec exposed through their traditional diet. METHODS In a prospective longitudinal study, we assessed 196 children (mean age, 11.3 years) on a visual go/no-go response inhibition paradigm. Pb, PCB, and mercury (Hg) concentrations were analyzed in cord and current blood samples. Hierarchical multiple regression analyses were conducted to examine the associations of contaminant levels to go/no-go performance (mean reaction time, percent correct go, percent correct no-go) and five ERPs [N2, P3, error-related negativity, error positivity (Pe), and correct response positivity (Pc)] after control for confounding variables. RESULTS Current blood Pb concentrations were associated with higher rates of false alarms and with decreased P3 amplitudes to go and no-go trials. Current plasma PCB-153 concentrations were associated with slower reaction times and with reduced amplitudes of the Pe and Pc response-related potentials. Hg concentrations were not related to any outcome on this task but showed significant interactions with other contaminants on certain outcomes. CONCLUSIONS These results suggest that Pb exposure during childhood impairs the child's ability to allocate the cognitive resources needed to correctly inhibit a prepotent response, resulting in increased impulsivity. By contrast, postnatal PCB exposure appears to affect processes associated with error monitoring, an aspect of behavioral regulation required to adequately adapt to the changing demands of the environment, which results in reduced task efficiency.
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Affiliation(s)
- Olivier Boucher
- Centre de recherche du Centre Hospitalier Universitaire de Québec, Québec, Canada
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Maugans TA, Farley C, Altaye M, Leach J, Cecil KM. Pediatric sports-related concussion produces cerebral blood flow alterations. Pediatrics 2012; 129:28-37. [PMID: 22129537 PMCID: PMC3255471 DOI: 10.1542/peds.2011-2083] [Citation(s) in RCA: 257] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
OBJECTIVES The pathophysiology of sports-related concussion (SRC) is incompletely understood. Human adult and experimental animal investigations have revealed structural axonal injuries, decreases in the neuronal metabolite N-acetyl aspartate, and reduced cerebral blood flow (CBF) after SRC and minor traumatic brain injury. The authors of this investigation explore these possibilities after pediatric SRC. PATIENTS AND METHODS Twelve children, ages 11 to 15 years, who experienced SRC were evaluated by ImPACT neurocognitive testing, T1 and susceptibility weighted MRI, diffusion tensor imaging, proton magnetic resonance spectroscopy, and phase contrast angiography at <72 hours, 14 days, and 30 days or greater after concussion. A similar number of age- and gender-matched controls were evaluated at a single time point. RESULTS ImPACT results confirmed statistically significant differences in initial total symptom score and reaction time between the SRC and control groups, resolving by 14 days for total symptom score and 30 days for reaction time. No evidence of structural injury was found on qualitative review of MRI. No decreases in neuronal metabolite N-acetyl aspartate or elevation of lactic acid were detected by proton magnetic resonance spectroscopy. Statistically significant alterations in CBF were documented in the SRC group, with reduction in CBF predominating (38 vs 48 mL/100 g per minute; P = .027). Improvement toward control values occurred in only 27% of the participants at 14 days and 64% at >30 days after SRC. CONCLUSIONS Pediatric SRC is primarily a physiologic injury, affecting CBF significantly without evidence of measurable structural, metabolic neuronal or axonal injury. Further study of CBF mechanisms is needed to explain patterns of recovery.
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Affiliation(s)
- Todd A. Maugans
- Division of Neurosurgery, Department of Surgery, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio,Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Chad Farley
- Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Mekibib Altaye
- Division of Epidemiology and Biostatistics,Department of Pediatrics
| | - James Leach
- Department of Pediatrics,,Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Kim M. Cecil
- Department of Pediatrics,,Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
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Bellinger DC. The protean toxicities of lead: new chapters in a familiar story. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2011; 8:2593-628. [PMID: 21845148 PMCID: PMC3155319 DOI: 10.3390/ijerph8072593] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 06/17/2011] [Accepted: 06/20/2011] [Indexed: 12/11/2022]
Abstract
Many times in the history of lead toxicology the view that "the problem" has been solved and is no longer a major health concern has prevailed, only to have further research demonstrate the prematurity of this judgment. In the last decade, an extraordinary amount of new research on lead has illustrated, all too clearly, that "the problem" has not disappeared, and that, in fact, it has dimensions never before considered. Recent risk assessments have concluded that research has yet to identify a threshold level below which lead can be considered "safe." Although children's intelligence has traditionally been considered to be the most sensitive endpoint, and used as the basis for risk assessment and standard setting, increased lead exposure has been associated with a wide variety of other morbidities both in children and adults, in some cases at biomarker levels comparable to those associated with IQ deficits in children. In adults, these endpoints include all-cause mortality and dysfunctions in the renal, cardiovascular, reproductive, central nervous systems. In children, IQ deficits are observed at blood lead levels well below 10 μg/dL, and the dose-effect relationship appears to be supra-linear. Other health endpoints associated with greater early-life lead exposure in children include ADHD, conduct disorder, aggression and delinquency, impaired dental health, and delayed sexual maturation. Studies employing neuroimaging modalities such as volumetric, diffusion tensor, and functional MRI are providing insights into the neural bases of the cognitive impairments associated with greater lead exposure.
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Affiliation(s)
- David C Bellinger
- Children's Hospital Boston, Farley Basement Box 127, 300 Longwood Avenue, Boston, MA 02115, USA.
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Mazumdar M, Bellinger DC, Gregas M, Abanilla K, Bacic J, Needleman HL. Low-level environmental lead exposure in childhood and adult intellectual function: a follow-up study. Environ Health 2011; 10:24. [PMID: 21450073 PMCID: PMC3072933 DOI: 10.1186/1476-069x-10-24] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 03/30/2011] [Indexed: 05/21/2023]
Abstract
BACKGROUND Early life lead exposure might be a risk factor for neurocognitive impairment in adulthood. OBJECTIVES We sought to assess the relationship between early life environmental lead exposure and intellectual function in adulthood. We also attempted to identify which time period blood-lead concentrations are most predictive of adult outcome. METHODS We recruited adults in the Boston area who had participated as newborns and young children in a prospective cohort study that examined the relationship between lead exposure and childhood intellectual function. IQ was measured using the Wechsler Abbreviated Scale of Intelligence (WASI). The association between lead concentrations and IQ scores was examined using linear regression. RESULTS Forty-three adults participated in neuropsychological testing. Childhood blood-lead concentration (mean of the blood-lead concentrations at ages 4 and 10 years) had the strongest relationship with Full-Scale IQ (β = -1.89 ± 0.70, p = 0.01). Full-scale IQ was also significantly related to blood-lead concentration at age 6 months (β = -1.66 ± 0.75, p = 0.03), 4 years (β = -0.90 ± 0.41, p = 0.03) and 10 years (β = -1.95 ± 0.80, p = 0.02). Adjusting for maternal IQ altered the significance of the regression coefficient. CONCLUSIONS Our study suggests that lead exposure in childhood predicts intellectual functioning in young adulthood. Our results also suggest that school-age lead exposure may represent a period of increased susceptibility. Given the small sample size, however, the potentially confounding effects of maternal IQ cannot be excluded and should be evaluated in a larger study.
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Affiliation(s)
- Maitreyi Mazumdar
- Department of Neurology, Children's Hospital Boston, 300 Longwood Avenue, Boston, MA USA
- Department of Environmental Health, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA USA
| | - David C Bellinger
- Department of Neurology, Children's Hospital Boston, 300 Longwood Avenue, Boston, MA USA
- Department of Environmental Health, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA USA
| | - Matthew Gregas
- Department of Neurology, Children's Hospital Boston, 300 Longwood Avenue, Boston, MA USA
- Clinical Research Program, Children's Hospital Boston, 300 Longwood Avenue, Boston, MA USA
| | - Kathleen Abanilla
- Department of Neurology, Children's Hospital Boston, 300 Longwood Avenue, Boston, MA USA
| | - Janine Bacic
- Clinical Research Program, Children's Hospital Boston, 300 Longwood Avenue, Boston, MA USA
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