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Romer SH, Miller KM, Sonner MJ, Ethridge VT, Gargas NM, Rohan JG. Changes in motor behavior and lumbar motoneuron morphology following repeated chlorpyrifos exposure in rats. PLoS One 2024; 19:e0305173. [PMID: 38875300 PMCID: PMC11178230 DOI: 10.1371/journal.pone.0305173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 05/26/2024] [Indexed: 06/16/2024] Open
Abstract
Chlorpyrifos is an organophosphate pesticide associated with numerous health effects including motor performance decrements. While many studies have focused on the health effects following acute chlorpyrifos poisonings, almost no studies have examined the effects on motoneurons following occupational-like exposures. The main objective of this study was to examine the broad effects of repeated occupational-like chlorpyrifos exposures on spinal motoneuron soma size relative to motor activity. To execute our objective, adult rats were exposed to chlorpyrifos via oral gavage once a day, five days a week for two weeks. Chlorpyrifos exposure effects were assessed either three days or two months following the last exposure. Three days following the last repeated chlorpyrifos exposure, there were transient effects in open-field motor activity and plasma cholinesterase activity levels. Two months following the chlorpyrifos exposures, there were delayed effects in sensorimotor gating, pro-inflammatory cytokines and spinal lumbar motoneuron soma morphology. Overall, these results offer support that subacute repeated occupational-like chlorpyrifos exposures have both short-term and longer-term effects in motor activity, inflammation, and central nervous system mechanisms.
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Affiliation(s)
- Shannon H Romer
- Environmental Health Effects Laboratory, Naval Medical Research Unit Dayton, Wright-Patterson AFB, Dayton, OH, United States of America
- Leidos, Reston, VA, United States of America
| | - Kaitlyn M Miller
- Environmental Health Effects Laboratory, Naval Medical Research Unit Dayton, Wright-Patterson AFB, Dayton, OH, United States of America
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States of America
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, United States of America
| | - Martha J Sonner
- Environmental Health Effects Laboratory, Naval Medical Research Unit Dayton, Wright-Patterson AFB, Dayton, OH, United States of America
- Leidos, Reston, VA, United States of America
| | - Victoria T Ethridge
- Environmental Health Effects Laboratory, Naval Medical Research Unit Dayton, Wright-Patterson AFB, Dayton, OH, United States of America
- Leidos, Reston, VA, United States of America
| | - Nathan M Gargas
- Environmental Health Effects Laboratory, Naval Medical Research Unit Dayton, Wright-Patterson AFB, Dayton, OH, United States of America
| | - Joyce G Rohan
- Environmental Health Effects Laboratory, Naval Medical Research Unit Dayton, Wright-Patterson AFB, Dayton, OH, United States of America
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Pathak D, Sriram K. Molecular Mechanisms Underlying Neuroinflammation Elicited by Occupational Injuries and Toxicants. Int J Mol Sci 2023; 24:2272. [PMID: 36768596 PMCID: PMC9917383 DOI: 10.3390/ijms24032272] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/17/2023] [Accepted: 01/17/2023] [Indexed: 01/26/2023] Open
Abstract
Occupational injuries and toxicant exposures lead to the development of neuroinflammation by activating distinct mechanistic signaling cascades that ultimately culminate in the disruption of neuronal function leading to neurological and neurodegenerative disorders. The entry of toxicants into the brain causes the subsequent activation of glial cells, a response known as 'reactive gliosis'. Reactive glial cells secrete a wide variety of signaling molecules in response to neuronal perturbations and thus play a crucial role in the progression and regulation of central nervous system (CNS) injury. In parallel, the roles of protein phosphorylation and cell signaling in eliciting neuroinflammation are evolving. However, there is limited understanding of the molecular underpinnings associated with toxicant- or occupational injury-mediated neuroinflammation, gliosis, and neurological outcomes. The activation of signaling molecules has biological significance, including the promotion or inhibition of disease mechanisms. Nevertheless, the regulatory mechanisms of synergism or antagonism among intracellular signaling pathways remain elusive. This review highlights the research focusing on the direct interaction between the immune system and the toxicant- or occupational injury-induced gliosis. Specifically, the role of occupational injuries, e.g., trips, slips, and falls resulting in traumatic brain injury, and occupational toxicants, e.g., volatile organic compounds, metals, and nanoparticles/nanomaterials in the development of neuroinflammation and neurological or neurodegenerative diseases are highlighted. Further, this review recapitulates the recent advancement related to the characterization of the molecular mechanisms comprising protein phosphorylation and cell signaling, culminating in neuroinflammation.
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Affiliation(s)
| | - Krishnan Sriram
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA
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3
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Costantini E, Masciarelli E, Casorri L, Di Luigi M, Reale M. Medicinal herbs and multiple sclerosis: Overview on the hard balance between new therapeutic strategy and occupational health risk. Front Cell Neurosci 2022; 16:985943. [PMID: 36439198 PMCID: PMC9688751 DOI: 10.3389/fncel.2022.985943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 10/20/2022] [Indexed: 11/11/2022] Open
Abstract
Multiple sclerosis (MS) is an autoimmune disease characterized by demyelination and axonal loss of the central nervous system (CNS). Despite its spread throughout the world, the mechanisms that determine its onset are still to be defined. Immunological, genetic, viral, and environmental factors and exposure to chemicals may trigger MS. Many studies have highlighted the anti-inflammatory and anti-oxidant effects of medicinal herbs, which make them a natural and complementary treatment for neurodegenerative diseases. A severe reduction of several MS symptoms occurs with herbal therapy. Thus, the request for medicinal plants with potential beneficial effects, for MS patients, is constantly increasing. Consequently, a production increase needs. Unfortunately, many medicinal herbs were untested and their action mechanism, possible adverse effects, contraindications, or interactions with other drugs, are poorly or not investigated. Keeping in mind the pathological mechanisms of MS and the oxidative damages and mitochondrial dysfunctions induced by pesticides, it is important to understand if pesticides used to increase agricultural productivity and their residues in medicinal plants, may increase the risk of developing MS in both workers and consumers. Studies providing some indication about the relationship between environmental exposure to pesticides and MS disease incidence are few, fragmentary, and discordant. The aim of this article is to provide a glance at the therapeutic potential of medicinal plants and at the risk for MS onset of pesticides used by medicinal plant growers and present in medicinal herbs.
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Affiliation(s)
- Erica Costantini
- Department of Medicine and Science of Aging, G. d’Annunzio University of Chieti–Pescara, Chieti, Italy
| | - Eva Masciarelli
- Department of Technological Innovations and Safety of Plants, Products and Anthropic Settlements, National Institute for Insurance Against Accidents at Work, Rome, Italy
| | - Laura Casorri
- Department of Technological Innovations and Safety of Plants, Products and Anthropic Settlements, National Institute for Insurance Against Accidents at Work, Rome, Italy
| | - Marco Di Luigi
- Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, INAIL Research Center, National Institute for Insurance Against Accidents at Work, Rome, Italy
| | - Marcella Reale
- Department of Innovative Technologies in Medicine and Dentistry, G. d’Annunzio University of Chieti–Pescara, Chieti, Italy
- *Correspondence: Marcella Reale,
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4
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Seth E, Chopra M. Neuroprotective efficacy of berberine following developmental exposure to chlorpyrifos in F1 generation of Wistar rats: Apoptosis-autophagy interplay. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 834:155292. [PMID: 35439518 DOI: 10.1016/j.scitotenv.2022.155292] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 04/10/2022] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
Chlorpyrifos (CPF), an organophosphate insecticide commonly used in agriculture and household applications, is considered a developmental neurotoxicant. This study aimed to explain the neuroprotective role of Berberine (BBR) against CPF-induced autophagy dysfunction and apoptotic neurodegeneration in the developing hippocampus. F1 generation of Wistar rats was exposed to CPF (3 mg/kg b.wt.) and co-treated with BBR (10 mg/kg b.wt) in two different exposure regimens, gestational (GD9-12 and GD17-21) and lactational (PND1-20). Our results demonstrated that CPF intoxication instigated cognitive and neurobehavioral impairment, oxidant-antioxidant imbalance, and histomorphological alterations in CA1, CA3, and DG regions of the offsprings. Furthermore, mRNA expression of pro-apoptotic genes (caspase3 and Bax) was upregulated, and that of anti-apoptotic BCl2 was downregulated. In addition, exposure to CPF also activated the autophagy inhibitor (mTOR) transcription and subsequently downregulated the expression of autophagy markers beclin1 and LC3-II. In contrast, gestational and lactational co-treatment of BBR significantly upregulated the enzymatic anti-oxidant bar of the hippocampus and attenuated histological alterations. Moreover, BBR co-treatments reduced apoptotic neurodegeneration in the hippocampal region by regulating the expression of apoptotic genes and upregulated the levels of autophagy, confirmed by ultrastructural studies, decreased gene expression and immunostaining of mTOR and increased, and increased expression gene expression and immunostaining of LC3-II positive cells. Our results confirm that treatment with BBR induces autophagy, which plays a neuroprotective role in CPF-induced developmental neuronal apoptosis in the F1 generation of Wistar rats by regulating the balance between autophagy and apoptosis.
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Affiliation(s)
- Era Seth
- Cytogenetics Laboratory, Department of Zoology, Panjab University, Chandigarh 160014, India
| | - Mani Chopra
- Cytogenetics Laboratory, Department of Zoology, Panjab University, Chandigarh 160014, India.
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McClelland SJ, Woodley SK. Developmental Exposure to Trace Concentrations of Chlorpyrifos Results in Nonmonotonic Changes in Brain Shape and Behavior in Amphibians. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:9379-9386. [PMID: 35704902 DOI: 10.1021/acs.est.2c01039] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Despite regulations and improved design, pesticides remain ubiquitous in the environment at relatively low, trace concentrations. To understand how prolonged exposure to trace pesticide concentrations impacts vertebrate brain development and behavior, we raised larval amphibians (northern leopard frogs, Lithobates pipiens) in 0, 1, or 10 μg/L of the organophosphorus pesticide chlorpyrifos (CPF) from hatching to metamorphosis. Tadpoles exposed to 1 μg/L CPF, but not 10 μg/L CPF, had changes in relative brain mass, relative telencephalon shape, and behavioral responses to a novel visual cue. Tadpoles exposed to 10 μg/L CPF had altered behavioral responses to predator-associated olfactory cues. After metamorphosis, frogs raised in 1 μg/L CPF, but not 10 μg/L CPF, had changes in the shape of their optic tectum and medulla. Thus, we provide robust evidence that even trace, yet ecologically realistic, concentrations of CPF have neurodevelopmental and behavioral effects that carry over to later life-history stages, further emphasizing the potent effects of trace levels of CPF on vertebrate development. Also, some but not all effects were nonmonotonic, meaning that effects were evident at the lowest but not at the higher concentration of CPF.
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Affiliation(s)
- Sara J McClelland
- Duquesne University, Pittsburgh, Pennsylvania 15217, United States
- Moravian University, Bethlehem, Pennsylvania 18018, United States
| | - Sarah K Woodley
- Duquesne University, Pittsburgh, Pennsylvania 15217, United States
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6
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Del Castilo I, Neumann AS, Lemos FS, De Bastiani MA, Oliveira FL, Zimmer ER, Rêgo AM, Hardoim CCP, Antunes LCM, Lara FA, Figueiredo CP, Clarke JR. Lifelong Exposure to a Low-Dose of the Glyphosate-Based Herbicide RoundUp ® Causes Intestinal Damage, Gut Dysbiosis, and Behavioral Changes in Mice. Int J Mol Sci 2022; 23:5583. [PMID: 35628394 PMCID: PMC9146949 DOI: 10.3390/ijms23105583] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 02/04/2023] Open
Abstract
RoundUp® (RUp) is a comercial formulation containing glyphosate (N-(phosphono-methyl) glycine), and is the world's leading wide-spectrum herbicide used in agriculture. Supporters of the broad use of glyphosate-based herbicides (GBH) claim they are innocuous to humans, since the active compound acts on the inhibition of enzymes which are absent in human cells. However, the neurotoxic effects of GBH have already been shown in many animal models. Further, these formulations were shown to disrupt the microbiome of different species. Here, we investigated the effects of a lifelong exposure to low doses of the GBH-RUp on the gut environment, including morphological and microbiome changes. We also aimed to determine whether exposure to GBH-RUp could harm the developing brain and lead to behavioral changes in adult mice. To this end, animals were exposed to GBH-RUp in drinking water from pregnancy to adulthood. GBH-RUp-exposed mice had no changes in cognitive function, but developed impaired social behavior and increased repetitive behavior. GBH-Rup-exposed mice also showed an activation of phagocytic cells (Iba-1-positive) in the cortical brain tissue. GBH-RUp exposure caused increased mucus production and the infiltration of plama cells (CD138-positive), with a reduction in phagocytic cells. Long-term exposure to GBH-RUp also induced changes in intestinal integrity, as demonstrated by the altered expression of tight junction effector proteins (ZO-1 and ZO-2) and a change in the distribution of syndecan-1 proteoglycan. The herbicide also led to changes in the gut microbiome composition, which is also crucial for the establishment of the intestinal barrier. Altogether, our findings suggest that long-term GBH-RUp exposure leads to morphological and functional changes in the gut, which correlate with behavioral changes that are similar to those observed in patients with neurodevelopmental disorders.
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Affiliation(s)
- Ingrid Del Castilo
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil; (I.D.C.); (C.P.F.)
| | - Arthur S. Neumann
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil; (A.S.N.); (F.S.L.); (F.L.O.)
| | - Felipe S. Lemos
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil; (A.S.N.); (F.S.L.); (F.L.O.)
| | - Marco A. De Bastiani
- Departamento de Farmacologia, Universidade Federal do Rio Grande do Sul, Porto Alegre 90040-193, RS, Brazil; (M.A.D.B.); (E.R.Z.)
| | - Felipe L. Oliveira
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil; (A.S.N.); (F.S.L.); (F.L.O.)
| | - Eduardo R. Zimmer
- Departamento de Farmacologia, Universidade Federal do Rio Grande do Sul, Porto Alegre 90040-193, RS, Brazil; (M.A.D.B.); (E.R.Z.)
| | - Amanda M. Rêgo
- Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro 21040-360, RJ, Brazil; (A.M.R.); (L.C.M.A.); (F.A.L.)
| | - Cristiane C. P. Hardoim
- Instituto de Biociências, Universidade Estadual Paulista, São Vicente 11380-972, SP, Brazil;
| | - Luis Caetano M. Antunes
- Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro 21040-360, RJ, Brazil; (A.M.R.); (L.C.M.A.); (F.A.L.)
- Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças de Populações Negligenciadas, Centro de Desenvolvimento Tecnológico em Saúde, Fundação Oswaldo Cruz, Rio de Janeiro 21040-361, RJ, Brazil
| | - Flávio A. Lara
- Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro 21040-360, RJ, Brazil; (A.M.R.); (L.C.M.A.); (F.A.L.)
| | - Claudia P. Figueiredo
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil; (I.D.C.); (C.P.F.)
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil; (A.S.N.); (F.S.L.); (F.L.O.)
| | - Julia R. Clarke
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil; (I.D.C.); (C.P.F.)
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil; (A.S.N.); (F.S.L.); (F.L.O.)
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Gestational exposures to organophosphorus insecticides: From acute poisoning to developmental neurotoxicity. Neuropharmacology 2020; 180:108271. [PMID: 32814088 DOI: 10.1016/j.neuropharm.2020.108271] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 07/03/2020] [Accepted: 08/10/2020] [Indexed: 11/22/2022]
Abstract
For over three-quarters of a century, organophosphorus (OP) insecticides have been ubiquitously used in agricultural, residential, and commercial settings and in public health programs to mitigate insect-borne diseases. Their broad-spectrum insecticidal effectiveness is accounted for by the irreversible inhibition of acetylcholinesterase (AChE), the enzyme that catalyzes acetylcholine (ACh) hydrolysis, in the nervous system of insects. However, because AChE is evolutionarily conserved, OP insecticides are also toxic to mammals, including humans, and acute OP intoxication remains a major public health concern in countries where OP insecticide usage is poorly regulated. Environmental exposures to OP levels that are generally too low to cause marked inhibition of AChE and to trigger acute signs of intoxication, on the other hand, represent an insidious public health issue worldwide. Gestational exposures to OP insecticides are particularly concerning because of the exquisite sensitivity of the developing brain to these insecticides. The present article overviews and discusses: (i) the health effects and therapeutic management of acute OP poisoning during pregnancy, (ii) epidemiological studies examining associations between environmental OP exposures during gestation and health outcomes of offspring, (iii) preclinical evidence that OP insecticides are developmental neurotoxicants, and (iv) potential mechanisms underlying the developmental neurotoxicity of OP insecticides. Understanding how gestational exposures to different levels of OP insecticides affect pregnancy and childhood development is critical to guiding implementation of preventive measures and direct research aimed at identifying effective therapeutic interventions that can limit the negative impact of these exposures on public health.
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8
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Pesticides, cognitive functions and dementia: A review. Toxicol Lett 2020; 326:31-51. [PMID: 32145396 DOI: 10.1016/j.toxlet.2020.03.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 03/02/2020] [Accepted: 03/03/2020] [Indexed: 12/13/2022]
Abstract
Pesticides are widely-used chemicals commonly applied in agriculture for the protection of crops from pests. Depending on the class of pesticides, the specific substances may have a specific set of adverse effects on humans, especially in cases of acute poisoning. In past years, evidence regarding sequelae of chronic, low-level exposure has been accumulating. Cognitive impairment and dementia heavily affect a person's quality of life and scientific data has been hinting towards an association between them and antecedent chronic pesticide exposure. Here, we reviewed animal and human studies exploring the association between pesticide exposure, cognition and dementia. Additionally, we present potential mechanisms through which pesticides may act neurotoxically and lead to neurodegeneration. Study designs rarely presented homogeneity and the estimation of the exposure to pesticides has been most frequently performed without measuring the synergic effects and the possible interactions between the toxicants within mixtures, and also overlooking low exposures to environmental toxicants. It is possible that a Real-Life Risk Simulation approach would represent a robust alternative for future studies, so that the safe exposure limits and the net risk that pesticides confer to impaired cognitive function can be examined. Previous studies that evaluated the effect of low dose chronic exposure to mixtures of pesticides and other chemicals intending to simulate real life exposure scenarios showed that hormetic neurobehavioral effects can appear after mixture exposure at doses considered safe for individual compounds and these effects can be exacerbated by a coexistence with specific conditions such as vitamin deficiency. However, there is an overall indication, derived from both epidemiologic and laboratory evidence, supporting an association between exposure to neurotoxic pesticides and cognitive dysfunction, dementia and Alzheimer's disease.
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Nesan D, Kurrasch DM. Gestational Exposure to Common Endocrine Disrupting Chemicals and Their Impact on Neurodevelopment and Behavior. Annu Rev Physiol 2019; 82:177-202. [PMID: 31738670 DOI: 10.1146/annurev-physiol-021119-034555] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Endocrine disrupting chemicals are common in our environment and act on hormone systems and signaling pathways to alter physiological homeostasis. Gestational exposure can disrupt developmental programs, permanently altering tissues with impacts lasting into adulthood. The brain is a critical target for developmental endocrine disruption, resulting in altered neuroendocrine control of hormonal signaling, altered neurotransmitter control of nervous system function, and fundamental changes in behaviors such as learning, memory, and social interactions. Human cohort studies reveal correlations between maternal/fetal exposure to endocrine disruptors and incidence of neurodevelopmental disorders. Here, we summarize the major literature findings of endocrine disruption of neurodevelopment and concomitant changes in behavior by four major endocrine disruptor classes:bisphenol A, polychlorinated biphenyls, organophosphates, and polybrominated diphenyl ethers. We specifically review studies of gestational and/or lactational exposure to understand the effects of early life exposure to these compounds and summarize animal studies that help explain human correlative data.
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Affiliation(s)
- Dinushan Nesan
- Department of Medical Genetics, University of Calgary, Calgary, Alberta T2N 4N1, Canada; , .,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Deborah M Kurrasch
- Department of Medical Genetics, University of Calgary, Calgary, Alberta T2N 4N1, Canada; , .,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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Abdelmalek MR, Beheiry EE, El-Shinety RM, Farag AT, Tayel SM. Scanning electron microscopic study of the effect of chlorpyrifos on the developing neural tube in comparison with Arsenic in mouse embryo. ALEXANDRIA JOURNAL OF MEDICINE 2019. [DOI: 10.1016/j.ajme.2015.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
- Miriam R.R.F. Abdelmalek
- Department of Human Anatomy and Embryology, Faculty of Medicine, University of Alexandria, Egypt
| | - Eman Elazab Beheiry
- Department of Human Anatomy and Embryology, Faculty of Medicine, University of Alexandria, Egypt
| | | | - Amina Tolba Farag
- Department of Pesticide Chemistry and toxicology, Faculty of Agriculture, University of Alexandria, Egypt
| | - Shawky Mahmoud Tayel
- Department of Human Anatomy and Embryology, Faculty of Medicine, University of Alexandria, Egypt
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11
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Leung MCK, Silva MH, Palumbo AJ, Lohstroh PN, Koshlukova SE, DuTeaux SB. Adverse outcome pathway of developmental neurotoxicity resulting from prenatal exposures to cannabis contaminated with organophosphate pesticide residues. Reprod Toxicol 2019; 85:12-18. [PMID: 30668982 DOI: 10.1016/j.reprotox.2019.01.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 11/07/2018] [Accepted: 01/14/2019] [Indexed: 01/11/2023]
Abstract
There is growing concern that increased use of medical and recreational cannabis may result in increased exposure to contaminants on the cannabis, such as pesticides. Several states are moving towards implementing robust regulation of the sales, cultivation, and manufacture of cannabis products. However, there are challenges with creating health-protective regulations in an industry that, to date, has been largely unregulated. The focus of this publication is a theoretical examination of what may happen when women are exposed pre-conceptually or during pregnancy to cannabis contaminated with pesticides. We propose an adverse outcome pathway of concomitant prenatal exposure to cannabinoids and the organophosphate pesticide chlorpyrifos by curating what we consider to be the key events at the molecular, cellular, and tissue levels that result in developmental neurotoxicity. The implications of this adverse outcome pathway underscore the need to elucidate the potential developmental neurotoxicity that may result from prenatal exposure to pesticide-contaminated cannabis.
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Affiliation(s)
- Maxwell C K Leung
- Department of Pesticide Regulation, California Environmental Protection Agency, Sacramento, 1001 I Street, Sacramento, CA 95812, United States.
| | - Marilyn H Silva
- Department of Pesticide Regulation, California Environmental Protection Agency, Sacramento, 1001 I Street, Sacramento, CA 95812, United States
| | - Amanda J Palumbo
- Department of Pesticide Regulation, California Environmental Protection Agency, Sacramento, 1001 I Street, Sacramento, CA 95812, United States
| | - Peter N Lohstroh
- Department of Pesticide Regulation, California Environmental Protection Agency, Sacramento, 1001 I Street, Sacramento, CA 95812, United States
| | - Svetlana E Koshlukova
- Department of Pesticide Regulation, California Environmental Protection Agency, Sacramento, 1001 I Street, Sacramento, CA 95812, United States
| | - Shelley B DuTeaux
- Department of Pesticide Regulation, California Environmental Protection Agency, Sacramento, 1001 I Street, Sacramento, CA 95812, United States
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12
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Silver MK, Shao J, Ji C, Zhu B, Xu L, Li M, Chen M, Xia Y, Kaciroti N, Lozoff B, Meeker JD. Prenatal organophosphate insecticide exposure and infant sensory function. Int J Hyg Environ Health 2019; 221:469-478. [PMID: 29402694 DOI: 10.1016/j.ijheh.2018.01.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 12/29/2017] [Accepted: 01/18/2018] [Indexed: 01/26/2023]
Abstract
BACKGROUND Occupational studies suggest that exposure to organophosphate insecticides (OPs) can lead to vision or hearing loss. Yet the effects of early-life exposure on visual and auditory function are unknown. Here we examined associations between prenatal OP exposure and grating visual acuity (VA) and auditory brainstem response (ABR) during infancy. METHODS 30 OPs were measured in umbilical cord blood using gas chromatography tandem mass spectrometry in a cohort of Chinese infants. Grating visual acuity (VA) (n = 179-200) and auditory brainstem response (ABR) (n = 139-183) were assessed at 6 weeks, 9 months, and 18 months. Outcomes included VA score, ABR wave V latency and central conduction time, and head circumference (HC). Associations between sensory outcomes during infancy and cord OPs were examined using linear mixed models. RESULTS Prenatal chlorpyrifos exposure was associated with lower 9-month grating VA scores; scores were 0.64 (95% CI: -1.22, -0.06) points lower for exposed versus unexposed infants (p = 0.03). The OPs examined were not associated with infant ABR latencies, but chlorpyrifos and phorate were both significantly inversely associated with HC at 9 months; HCs were 0.41 (95% CI: 0.75, 0.6) cm and 0.44 (95% CI: 0.88, 0.1) cm smaller for chlorpyrifos (p = 0.02) and phorate (p = 0.04), respectively. CONCLUSIONS We found deficits in grating VA and HC in 9-month-old infants with prenatal exposure to chlorpyrifos. The clinical significance of these small but statistically significant deficits is unclear. However, the disruption of visual or auditory pathway maturation in infancy could potentially negatively affect downstream cognitive development.
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Affiliation(s)
- Monica K Silver
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jie Shao
- Department of Child Health Care, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Chai Ji
- Department of Child Health Care, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Binquan Zhu
- Department of Child Health Care, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Lin Xu
- Department of Child Health Care, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Mingyan Li
- Department of Child Health Care, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Minjian Chen
- Institute of Toxicology, Nanjing Medical University, Nanjing 210029, China
| | - Yankai Xia
- Institute of Toxicology, Nanjing Medical University, Nanjing 210029, China
| | - Niko Kaciroti
- Center for Human Growth and Development, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biostatistics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Betsy Lozoff
- Center for Human Growth and Development, University of Michigan, Ann Arbor, MI 48109, USA
| | - John D Meeker
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI 48109, USA.
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Guignet M, Lein PJ. Neuroinflammation in organophosphate-induced neurotoxicity. ROLE OF INFLAMMATION IN ENVIRONMENTAL NEUROTOXICITY 2019. [DOI: 10.1016/bs.ant.2018.10.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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14
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Silver MK, Shao J, Zhu B, Chen M, Xia Y, Kaciroti N, Lozoff B, Meeker JD. Prenatal naled and chlorpyrifos exposure is associated with deficits in infant motor function in a cohort of Chinese infants. ENVIRONMENT INTERNATIONAL 2017; 106:248-256. [PMID: 28602489 PMCID: PMC5533622 DOI: 10.1016/j.envint.2017.05.015] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 05/16/2017] [Accepted: 05/17/2017] [Indexed: 05/06/2023]
Abstract
BACKGROUND Organophosphate insecticides (OPs) are used worldwide, yet despite nearly ubiquitous exposure in the general population, few have been studied outside the laboratory. Fetal brains undergo rapid growth and development, leaving them susceptible to long-term effects of neurotoxic OPs. The objective here was to investigate the extent to which prenatal exposure to OPs affects infant motor development. METHODS 30 OPs were measured in umbilical cord blood using gas chromatography tandem mass spectrometry in a cohort of Chinese infants. Motor function was assessed at 6-weeks and 9-months using Peabody Developmental Motor Scales 2nd edition (PDMS-2) (n=199). Outcomes included subtest scores: reflexes, stationary, locomotion, grasping, visual-motor integration (V-M), composite scores: gross (GM), fine (FM), total motor (TM), and standardized motor quotients: gross (GMQ), fine (FMQ), total motor (TMQ). RESULTS Naled, methamidophos, trichlorfon, chlorpyrifos, and phorate were detected in ≥10% of samples. Prenatal naled and chlorpyrifos were associated with decreased 9-month motor function. Scores were 0.55, 0.85, and 0.90 points lower per 1ng/mL increase in log-naled, for V-M (p=0.04), FM (p=0.04), and FMQ (p=0.08), respectively. For chlorpyrifos, scores were 0.50, 1.98, 0.80, 1.91, 3.49, 2.71, 6.29, 2.56, 2.04, and 2.59 points lower for exposed versus unexposed infants, for reflexes (p=0.04), locomotion (p=0.02), grasping (p=0.05), V-M (p<0.001), GM (p=0.007), FM (p=0.002), TM (p<0.001), GMQ (p=0.01), FMQ (p=0.07), and TMQ (p=0.008), respectively. Girls appeared to be more sensitive to the negative effects of OPs on 9-month motor function than boys. CONCLUSIONS We found deficits in 9-month motor function in infants with prenatal exposure to naled and chlorpyrifos. Naled is being aerially sprayed to combat mosquitoes carrying Zika virus, yet this is the first non-occupational human study of its health effects. Delays in early-motor skill acquisition may be detrimental for downstream development and cognition.
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Affiliation(s)
- Monica K Silver
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jie Shao
- Department of Child Health Care, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Binquan Zhu
- Department of Child Health Care, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Minjian Chen
- Institute of Toxicology, Nanjing Medical University, Nanjing 210029, China
| | - Yankai Xia
- Institute of Toxicology, Nanjing Medical University, Nanjing 210029, China
| | - Niko Kaciroti
- Center for Human Growth and Development, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biostatistics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Betsy Lozoff
- Center for Human Growth and Development, University of Michigan, Ann Arbor, MI 48109, USA
| | - John D Meeker
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI 48109, USA.
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Sturza J, Silver MK, Xu L, Li M, Mai X, Xia Y, Shao J, Lozoff B, Meeker J. Prenatal exposure to multiple pesticides is associated with auditory brainstem response at 9months in a cohort study of Chinese infants. ENVIRONMENT INTERNATIONAL 2016; 92-93:478-485. [PMID: 27166702 PMCID: PMC4902769 DOI: 10.1016/j.envint.2016.04.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 04/13/2016] [Accepted: 04/22/2016] [Indexed: 05/29/2023]
Abstract
BACKGROUND Pesticides are associated with poorer neurodevelopmental outcomes, but little is known about the effects on sensory functioning. METHODS Auditory brainstem response (ABR) and pesticide data were available for 27 healthy, full-term 9-month-old infants participating in a larger study of early iron deficiency and neurodevelopment. Cord blood was analyzed by gas chromatography-mass spectrometry for levels of 20 common pesticides. The ABR forward-masking condition consisted of a click stimulus (masker) delivered via ear canal transducers followed by an identical stimulus delayed by 8, 16, or 64 milliseconds (ms). ABR peak latencies were evaluated as a function of masker-stimulus time interval. Shorter wave latencies reflect faster neural conduction, more mature auditory pathways, and greater degree of myelination. Linear regression models were used to evaluate associations between total number of pesticides detected and ABR outcomes. We considered an additive or synergistic effect of poor iron status by stratifying our analysis by newborn ferritin (based on median split). RESULTS Infants in the sample were highly exposed to pesticides; a mean of 4.1 pesticides were detected (range 0-9). ABR Wave V latency and central conduction time (CCT) were associated with the number of pesticides detected in cord blood for the 64ms and non-masker conditions. A similar pattern seen for CCT from the 8ms and 16ms conditions, although statistical significance was not reached. Increased pesticide exposure was associated with longer latency. The relation between number of pesticides detected in cord blood and CCT depended on the infant's cord blood ferritin level. Specifically, the relation was present in the lower cord blood ferritin group but not the higher cord blood ferritin group. CONCLUSIONS ABR processing was slower in infants with greater prenatal pesticide exposure, indicating impaired neuromaturation. Infants with lower cord blood ferritin appeared to be more sensitive to the effects of prenatal pesticide exposure on ABR latency delay, suggesting an additive or multiplicative effect.
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Affiliation(s)
- Julie Sturza
- Center for Human Growth and Development, University of Michigan, Ann Arbor, MI, USA.
| | - Monica K Silver
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA.
| | - Lin Xu
- Department of Child Health Care, Children's Hospital Zhejiang University School of Medicine, Zhejiang, China.
| | - Mingyan Li
- Department of Child Health Care, Children's Hospital Zhejiang University School of Medicine, Zhejiang, China.
| | - Xiaoqin Mai
- Department of Psychology, Renmin University of China, Beijing, China.
| | - Yankai Xia
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing, China.
| | - Jie Shao
- Department of Child Health Care, Children's Hospital Zhejiang University School of Medicine, Zhejiang, China.
| | - Betsy Lozoff
- Center for Human Growth and Development, University of Michigan, Ann Arbor, MI, USA.
| | - John Meeker
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA.
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Fluegge KR, Nishioka M, Wilkins JR. Effects of simultaneous prenatal exposures to organophosphate and synthetic pyrethroid insecticides on infant neurodevelopment at three months of age. JOURNAL OF ENVIRONMENTAL TOXIOLOGY AND PUBLIC HEALTH 2016; 1:60-73. [PMID: 28580452 DOI: 10.5281/zenodo.218417] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Both prenatal organophosphate (OP) and pyrethroid (PYRE) insecticide exposures have been inconsistently linked with poorer neurodevelopmental outcomes. However, given that neither exposure occurs in isolation, and both classes are neurotoxic, it is important to consider both classes when evaluating these outcomes. Employing biomarkers of pesticide exposure, this research describes the effects of prenatal urinary metabolite levels of PYRE and OP insecticides, measured in both the second and third trimesters of pregnancy and postnatal urinary metabolite levels measured at 2 months of age, on child neurodevelopment at three months of age. Neurodevelopmental data were obtained by administration of the Bayley Scales of Infant Development-II (BSID-II). Generalized linear models using maximum likelihood estimation were used to evaluate the relationship between the indicators of motor and mental neurobehavioral development obtained for 118 infants and prenatal insecticide exposure, accounting for the concurrent infant insecticide exposure. Urinary measures of the PYRE metabolites 3-phenoxybenzoic acid (3PBA) and trans-3-(2,2-dichlorovinyl)-2,2 dimethylcyclopropane-1-carboxylic acid (trans-DCCA) in the third trimester of pregnancy had significant, albeit opposite, effects on mental functioning at three months of age. We observed no significant (p < 0.05) effects on motor development. These results were robust to second month infant urine measures of 3,5,6-trichloro-2-pyridinol (metabolite of OP chlorpyrifos), which independently had a significant and negative influence on mental functioning. Prenatal PYRE exposures exert heterogeneous effects by class on mental, but not motor, functioning at three months of age.
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Affiliation(s)
- Kyle R Fluegge
- Department of Agricultural, Environmental, and Development Economics, College of Food, Agriculture and Environmental Sciences.,Division of Epidemiology, College of Public Health, The Ohio State University, Columbus, OH 43210, USA.,Institute for Health and Environmental Research, Cleveland, OH 44118, USA.,Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, OH, 44106 USA (current affiliation)
| | - Marcia Nishioka
- Battelle Memorial Institute, Columbus, OH 43201.,Division of Environmental Health Sciences, College of Public Health, The Ohio State University, Columbus, OH 43210
| | - J R Wilkins
- Division of Epidemiology, College of Public Health, The Ohio State University, Columbus, OH 43210, USA
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Slotkin TA, Skavicus S, Seidler FJ. Prenatal drug exposures sensitize noradrenergic circuits to subsequent disruption by chlorpyrifos. Toxicology 2015; 338:8-16. [PMID: 26419632 DOI: 10.1016/j.tox.2015.09.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 09/11/2015] [Accepted: 09/24/2015] [Indexed: 11/20/2022]
Abstract
We examined whether nicotine or dexamethasone, common prenatal drug exposures, sensitize the developing brain to chlorpyrifos. We gave nicotine to pregnant rats throughout gestation at a dose (3mg/kg/day) producing plasma levels typical of smokers; offspring were then given chlorpyrifos on postnatal days 1-4, at a dose (1mg/kg) that produces minimally-detectable inhibition of brain cholinesterase activity. In a parallel study, we administered dexamethasone to pregnant rats on gestational days 17-19 at a standard therapeutic dose (0.2mg/kg) used in the management of preterm labor, followed by postnatal chlorpyrifos. We evaluated cerebellar noradrenergic projections, a known target for each agent, and contrasted the effects with those in the cerebral cortex. Either drug augmented the effect of chlorpyrifos, evidenced by deficits in cerebellar β-adrenergic receptors; the receptor effects were not due to increased systemic toxicity or cholinesterase inhibition, nor to altered chlorpyrifos pharmacokinetics. Further, the deficits were not secondary adaptations to presynaptic hyperinnervation/hyperactivity, as there were significant deficits in presynaptic norepinephrine levels that would serve to augment the functional consequence of receptor deficits. The pretreatments also altered development of cerebrocortical noradrenergic circuits, but with a different overall pattern, reflecting the dissimilar developmental stages of the regions at the time of exposure. However, in each case the net effects represented a change in the developmental trajectory of noradrenergic circuits, rather than simply a continuation of an initial injury. Our results point to the ability of prenatal drug exposure to create a subpopulation with heightened vulnerability to environmental neurotoxicants.
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Affiliation(s)
- Theodore A Slotkin
- Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
| | - Samantha Skavicus
- Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Frederic J Seidler
- Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
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18
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Pesticides exposure as etiological factors of Parkinson's disease and other neurodegenerative diseases—A mechanistic approach. Toxicol Lett 2014; 230:85-103. [PMID: 24503016 DOI: 10.1016/j.toxlet.2014.01.039] [Citation(s) in RCA: 254] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 12/06/2013] [Accepted: 01/27/2014] [Indexed: 12/12/2022]
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Chen XP, Chen WF, Wang DW. Prenatal organophosphates exposure alternates the cleavage plane orientation of apical neural progenitor in developing neocortex. PLoS One 2014; 9:e95343. [PMID: 24740262 PMCID: PMC3989278 DOI: 10.1371/journal.pone.0095343] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 03/25/2014] [Indexed: 11/24/2022] Open
Abstract
Prenatal organophosphate exposure elicits long-term brain cytoarchitecture and cognitive function impairments, but the mechanism underlying the onset and development of neural progenitors remain largely unclear. Using precise positioned brain slices, we observed an alternated cleavage plane bias that emerged in the mitotic neural progenitors of embryonal neocortex with diazinion (DZN) and chlorpyrifos (CPF) pretreatment. In comparison with the control, DZN and CPF treatment induced decrease of vertical orientation, increase of oblique orientation, and increase of horizontal orientation. That is, the cleavage plane orientation bias had been rotated from vertical to horizontal after DZN and CPF treatment. Meanwhile, general morphology and mitotic index of the progenitors were unchanged. Acephate (ACP), another common organophosphate, had no significant effects on the cleavage plane orientation, cell morphology and mitotic index. These results represent direct evidence for the toxicity mechanism in onset multiplication of neural progenitors.
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Affiliation(s)
- Xiao-Ping Chen
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, China
- * E-mail:
| | - Wei-Feng Chen
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, China
| | - Da-Wei Wang
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, China
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20
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Silva BA, Einarsdóttir Ó, Fink AL, Uversky VN. Biophysical Characterization of α-Synuclein and Rotenone Interaction. Biomolecules 2013; 3:703-32. [PMID: 24970188 PMCID: PMC4030960 DOI: 10.3390/biom3030703] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 09/21/2013] [Accepted: 09/23/2013] [Indexed: 11/29/2022] Open
Abstract
Previous studies revealed that pesticides interact with α-synuclein and accelerate the rate of fibrillation. These results are consistent with the prevailing hypothesis that the direct interaction of α-synuclein with pesticides is one of many suspected factors leading to α-synuclein fibrillation and ultimately to Parkinson's disease. In this study, the biophysical properties and fibrillation kinetics of α-synuclein in the presence of rotenone were investigated and, more specifically, the effects of rotenone on the early-stage misfolded forms of α-synuclein were considered. The thioflavine T (ThT) fluorescence assay studies provide evidence that early-phase misfolded α-synuclein forms are affected by rotenone and that the fibrillation process is accelerated. Further characterization by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) shows that rotenone increases the amount of ordered secondary structure in this intrinsically disordered protein. Morphological characterization by transmission electron microscopy (TEM) and atomic force microscopy (AFM) provide visualization of the differences in the aggregated α-synuclein species developing during the early kinetics of the fibrillation process in the absence and presence of rotenone. We believe that these data provide useful information for a better understanding of the molecular basis of rotenone-induced misfolding and aggregation of α-synuclein.
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Affiliation(s)
- Blanca A. Silva
- Department of Chemistry and Biochemistry, University of California, 156 High Street, Santa Cruz, CA 95064, USA; E-Mails: (B.A.S.); (Ó.E.)
| | - Ólöf Einarsdóttir
- Department of Chemistry and Biochemistry, University of California, 156 High Street, Santa Cruz, CA 95064, USA; E-Mails: (B.A.S.); (Ó.E.)
| | - Anthony L. Fink
- Department of Chemistry and Biochemistry, University of California, 156 High Street, Santa Cruz, CA 95064, USA; E-Mails: (B.A.S.); (Ó.E.)
| | - Vladimir N. Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer’s Research Institute, Morsani College of Medicine, University of South Florida; 12901 Bruce B. Downs Blvd., MDC 7, Tampa, FL 33612, USA
- Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino 142292, Moscow Region, Russia
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22
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Wang L, Ohishi T, Akane H, Shiraki A, Itahashi M, Mitsumori K, Shibutani M. Reversible effect of developmental exposure to chlorpyrifos on late-stage neurogenesis in the hippocampal dentate gyrus in mouse offspring. Reprod Toxicol 2013; 38:25-36. [DOI: 10.1016/j.reprotox.2013.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Revised: 01/17/2013] [Accepted: 02/07/2013] [Indexed: 12/20/2022]
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23
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Bozkurt A, Yardan T, Ciftcioglu E, Baydin A, Hakligor A, Bitigic M, Bilge S. Time course of serum S100B protein and neuron-specific enolase levels of a single dose of chlorpyrifos in rats. Basic Clin Pharmacol Toxicol 2012; 107:893-8. [PMID: 20456333 DOI: 10.1111/j.1742-7843.2010.00593.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Organophosphate (OP) compounds are a large class of chemicals, many of which are used as pesticides. It is suggested that OPs specifically affect glia and neurons. Effects of acute exposure to chlorpyrifos (CPF), which is a common organophosphorus pesticide used worldwide, on neuron-specific enolase (NSE) and S100B levels in rat blood during 7 days were assessed. Rats were evaluated either before (0 hr) or 2, 12, 24, 48 and 168 hr (7 days) after injection of CPF (279 mg/kg, s.c.) or vehicle (peanut oil, 2 ml/kg, s.c.) for clinical signs of toxicity. Immediately after the evaluation of toxicity, blood samples were taken for biochemical assays. CPF administration produced decreases in body-weight and temperature, which were observed for first time at 12 hr after CPF administration and continued for 168 hr (p < 0.05-0.001). Serum S100B and NSE levels were acutely increased 2 hr after CPF administration and remained high at 12 hr (p < 0.01-0.001). NSE and S100B levels were not different in either CPF or vehicle groups at following time points. Serum butyrylcholinesterase (EC 3.1.1.8; BuChE) activity was dramatically reduced at 2 hr after CPF and remained low at each time points during 7 days (p < 0.01-0.001). Our results suggest that the usefulness of serum levels of these glia- and neuron-specific marker proteins in assessing OP toxicity, specifically CPF-induced toxicity.
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Affiliation(s)
- Ayhan Bozkurt
- Department of Physiology, Ondokuz Mayıs University, School of Medicine, Samsun, Turkey.
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24
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Brain anomalies in children exposed prenatally to a common organophosphate pesticide. Proc Natl Acad Sci U S A 2012; 109:7871-6. [PMID: 22547821 DOI: 10.1073/pnas.1203396109] [Citation(s) in RCA: 296] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Prenatal exposure to chlorpyrifos (CPF), an organophosphate insecticide, is associated with neurobehavioral deficits in humans and animal models. We investigated associations between CPF exposure and brain morphology using magnetic resonance imaging in 40 children, 5.9-11.2 y, selected from a nonclinical, representative community-based cohort. Twenty high-exposure children (upper tertile of CPF concentrations in umbilical cord blood) were compared with 20 low-exposure children on cortical surface features; all participants had minimal prenatal exposure to environmental tobacco smoke and polycyclic aromatic hydrocarbons. High CPF exposure was associated with enlargement of superior temporal, posterior middle temporal, and inferior postcentral gyri bilaterally, and enlarged superior frontal gyrus, gyrus rectus, cuneus, and precuneus along the mesial wall of the right hemisphere. Group differences were derived from exposure effects on underlying white matter. A significant exposure × IQ interaction was derived from CPF disruption of normal IQ associations with surface measures in low-exposure children. In preliminary analyses, high-exposure children did not show expected sex differences in the right inferior parietal lobule and superior marginal gyrus, and displayed reversal of sex differences in the right mesial superior frontal gyrus, consistent with disruption by CPF of normal behavioral sexual dimorphisms reported in animal models. High-exposure children also showed frontal and parietal cortical thinning, and an inverse dose-response relationship between CPF and cortical thickness. This study reports significant associations of prenatal exposure to a widely used environmental neurotoxicant, at standard use levels, with structural changes in the developing human brain.
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26
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Banks CN, Lein PJ. A review of experimental evidence linking neurotoxic organophosphorus compounds and inflammation. Neurotoxicology 2012; 33:575-84. [PMID: 22342984 DOI: 10.1016/j.neuro.2012.02.002] [Citation(s) in RCA: 152] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 01/31/2012] [Accepted: 02/01/2012] [Indexed: 01/14/2023]
Abstract
Organophosphorus (OP) nerve agents and pesticides inhibit acetylcholinesterase (AChE), and this is thought to be a primary mechanism mediating the neurotoxicity of these compounds. However, a number of observations suggest that mechanisms other than or in addition to AChE inhibition contribute to OP neurotoxicity. There is significant experimental evidence that acute OP intoxication elicits a robust inflammatory response, and emerging evidence suggests that chronic repeated low-level OP exposure also upregulates inflammatory mediators. A critical question that is just beginning to be addressed experimentally is the pathophysiologic relevance of inflammation in either acute or chronic OP intoxication. The goal of this article is to provide a brief review of the current status of our knowledge linking inflammation to OP intoxication, and to discuss the implications of these findings in the context of therapeutic and diagnostic approaches to OP neurotoxicity.
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Affiliation(s)
- Christopher N Banks
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, One Shields Ave., Davis, CA 95616, USA.
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27
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Li AA, Lowe KA, McIntosh LJ, Mink PJ. Evaluation of epidemiology and animal data for risk assessment: chlorpyrifos developmental neurobehavioral outcomes. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2012; 15:109-184. [PMID: 22401178 PMCID: PMC3386549 DOI: 10.1080/10937404.2012.645142] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Developmental neurobehavioral outcomes attributed to exposure to chlorpyrifos (CPF) obtained from epidemiologic and animal studies published before June 2010 were reviewed for risk assessment purposes. For epidemiological studies, this review considered (1) overall strength of study design, (2) specificity of CPF exposure biomarkers, (3) potential for bias, and (4) Hill guidelines for causal inference. In the case of animal studies, this review focused on evaluating the consistency of outcomes for developmental neurobehavioral endpoints from in vivo mammalian studies that exposed dams and/or offspring to CPF prior to weaning. Developmental neuropharmacologic and neuropathologic outcomes were also evaluated. Experimental design and methods were examined as part of the weight of evidence. There was insufficient evidence that human developmental exposures to CPF produce adverse neurobehavioral effects in infants and children across different cohort studies that may be relevant to CPF exposure. In animals, few behavioral parameters were affected following gestational exposures to 1 mg/kg-d but were not consistently reported by different laboratories. For postnatal exposures, behavioral effects found in more than one study at 1 mg/kg-d were decreased errors on a radial arm maze in female rats and increased errors in males dosed subcutaneously from postnatal day (PND) 1 to 4. A similar finding was seen in rats exposed orally from PND 1 to 21 with incremental dose levels of 1, 2, and 4 mg/kg-d, but not in rats dosed with constant dose level of 1 mg/kg-d. Neurodevelopmental behavioral, pharmacological, and morphologic effects occurred at doses that produced significant brain or red blood cell acetylcholinesterase inhibition in dams or offspring.
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Affiliation(s)
- Abby A Li
- Exponent Health Sciences Group, Menlo Park, California, USA.
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28
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Tilton FA, Tilton SC, Bammler TK, Beyer RP, Stapleton PL, Scholz NL, Gallagher EP. Transcriptional impact of organophosphate and metal mixtures on olfaction: copper dominates the chlorpyrifos-induced response in adult zebrafish. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2011; 102:205-15. [PMID: 21356183 PMCID: PMC3991301 DOI: 10.1016/j.aquatox.2011.01.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Revised: 01/14/2011] [Accepted: 01/27/2011] [Indexed: 05/06/2023]
Abstract
Chemical exposures in fish have been linked to loss of olfaction leading to an inability to detect predators and prey and decreased survival. However, the mechanisms underlying olfactory neurotoxicity are not well characterized, especially in environmental exposures which involve chemical mixtures. We used zebrafish to characterize olfactory transcriptional responses by two model olfactory inhibitors, the pesticide chlorpyrifos (CPF) and mixtures of CPF with the neurotoxic metal copper (Cu). Microarray analysis was performed on RNA from olfactory tissues of zebrafish exposed to CPF alone or to a mixture of CPF and Cu. Gene expression profiles were analyzed using principal component analysis and hierarchical clustering, whereas gene set analysis was used to identify biological themes in the microarray data. Microarray results were confirmed by real-time PCR on genes serving as potential biomarkers of olfactory injury. In addition, we mined our previously published Cu-induced zebrafish olfactory transcriptional response database (Tilton et al., 2008) for the purposes of discriminating pathways of olfaction impacted by either the individual agents or the CPF-Cu mixture transcriptional signatures. CPF exposure altered the expression of gene pathways associated with cellular morphogenesis and odorant binding, but not olfactory signal transduction, a known olfactory pathway for Cu. The mixture profiles shared genes from the Cu and CPF datasets, whereas some genes were altered only by the mixtures. The transcriptional signature of the mixtures was more similar to that in zebrafish exposed to Cu alone than for CPF. In conclusion, exposure to a mixture containing a common environmental metal and pesticide causes a unique transcriptional signature that is heavily influenced by the metal, even when organophosphate predominates.
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Affiliation(s)
- Fred A. Tilton
- Department of Environmental Health and Occupational Health Sciences, University of Washington, Seattle, WA
| | - Susan C. Tilton
- Department of Environmental Health and Occupational Health Sciences, University of Washington, Seattle, WA
| | - Theo K. Bammler
- Department of Environmental Health and Occupational Health Sciences, University of Washington, Seattle, WA
| | - Richard P. Beyer
- Department of Environmental Health and Occupational Health Sciences, University of Washington, Seattle, WA
| | - Patricia L. Stapleton
- Department of Environmental Health and Occupational Health Sciences, University of Washington, Seattle, WA
| | - Nathaniel L. Scholz
- NOAA Fisheries, Northwest Fisheries Science Center, 2725 Montlake Blvd. E., Seattle, WA 98112
| | - Evan P. Gallagher
- Department of Environmental Health and Occupational Health Sciences, University of Washington, Seattle, WA
- Address correspondence to: Evan P. Gallagher, Department of Environmental and Occupational Health Sciences, School of Public Health and Community Medicine, 4225 Roosevelt Way NE Suite 100, University of Washington, Seattle WA 98105-6099. Telephone: (206) 616-4739. Fax: (206) 685-4696.
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Tilton FA, Bammler TK, Gallagher EP. Swimming impairment and acetylcholinesterase inhibition in zebrafish exposed to copper or chlorpyrifos separately, or as mixtures. Comp Biochem Physiol C Toxicol Pharmacol 2011; 153:9-16. [PMID: 20692364 PMCID: PMC3034093 DOI: 10.1016/j.cbpc.2010.07.008] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 07/20/2010] [Accepted: 07/25/2010] [Indexed: 10/19/2022]
Abstract
Pesticides such as chlorpyrifos (CPF) and metals such as copper can impair swimming behavior in fish. However, the impact to swimming behavior from exposure to mixtures of neurotoxicants has received little attention. In the current study, we analyzed spontaneous swimming rates of adult zebrafish (Danio rerio) to investigate in vivo mixture interactions involving two chemical classes. Zebrafish were exposed to the neurotoxicants copper chloride (CuCl, 0.1 μM, 0.25 μM, 0.6 μM, or 6.3, 16, 40 ppb), chlorpyrifos (CPF, 0.1 μM, 0.25 μM, 0.6 μM, or 35, 88, 220 ppb) and binary mixtures for 24h to better understand the effects of Cu on CPF neurotoxicity. Exposure to CPF increased the number of animals undergoing freeze responses (an anti-predator behavior) and, at the highest CPF dose (0.6 μM), elicited a decrease in zebrafish swimming rates. Interestingly, the addition of Cu caused a reduction in the number of zebrafish in the CPF exposure groups undergoing freeze responses. There was no evidence of additive or synergistic toxicity between Cu and CPF. Although muscle AChE activity was significantly reduced by CPF, there was a relatively poor relationship among muscle AChE concentrations and swimming behavior, suggesting non-muscle AChE mechanisms in the loss of swimming behavior. In summary, we have observed a modulating effect of Cu on CPF swimming impairment that appears to involve both AChE and non-AChE mechanisms. Our study supports the utility of zebrafish in understanding chemical mixture interactions and neurobehavioral injury.
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Affiliation(s)
| | | | - Evan P. Gallagher
- Address correspondence to: Dr. Evan P. Gallagher, Department of Environmental and Occupational Health Sciences, University of Washington, 4225 Roosevelt Way Northeast, Suite 100, Seattle, WA 98105-6099, USA, Telephone: 206 616 4739; Fax: 206 685 4696,
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Huang QY, Huang L, Huang HQ. Proteomic analysis of methyl parathion-responsive proteins in zebrafish (Danio rerio) brain. Comp Biochem Physiol C Toxicol Pharmacol 2011; 153:67-74. [PMID: 20826231 DOI: 10.1016/j.cbpc.2010.08.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 08/30/2010] [Accepted: 08/30/2010] [Indexed: 12/22/2022]
Abstract
Methyl parathion (MP), an organophosphorus pesticide used worldwide, has been associated with a wide spectrum of toxic effects on organisms in the environment. This study set out to analyze the alteration of protein profiles in MP-exposed zebrafish (Danio rerio) brain and find the proteins responsive to MP toxicity. Zebrafish were subjected to 1, 3 and 5mg/L MP and the proteomic changes in their brains were revealed using two-dimensional gel electrophoresis. Six protein spots were observed to be significantly changed by MP exposure. Among these, 4 spots were down-regulated, while 2 spots were up-regulated. These altered spots were excised from the gels and identified by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry and database searching. The results indicate that these proteins were involved in binding, catalysis, regulation of energy metabolism and cell structure. These data may provide novel biomarkers for the evaluation of MP contamination and useful insights for understanding the mechanisms of MP toxicity.
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Affiliation(s)
- Qing-Yu Huang
- Department of Biochemistry and Biotechnology, School of Life Sciences, Xiamen University, Xiamen 361005, China
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31
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Diazinon oxon interferes with differentiation of rat C6 glioma cells. Toxicol In Vitro 2009; 23:1548-52. [DOI: 10.1016/j.tiv.2009.07.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 06/12/2009] [Accepted: 07/06/2009] [Indexed: 11/22/2022]
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Saulsbury MD, Heyliger SO, Wang K, Johnson DJ. Chlorpyrifos induces oxidative stress in oligodendrocyte progenitor cells. Toxicology 2009; 259:1-9. [DOI: 10.1016/j.tox.2008.12.026] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Revised: 12/08/2008] [Accepted: 12/24/2008] [Indexed: 11/30/2022]
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Bjørling-Poulsen M, Andersen HR, Grandjean P. Potential developmental neurotoxicity of pesticides used in Europe. Environ Health 2008; 7:50. [PMID: 18945337 PMCID: PMC2577708 DOI: 10.1186/1476-069x-7-50] [Citation(s) in RCA: 205] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Accepted: 10/22/2008] [Indexed: 05/18/2023]
Abstract
Pesticides used in agriculture are designed to protect crops against unwanted species, such as weeds, insects, and fungus. Many compounds target the nervous system of insect pests. Because of the similarity in brain biochemistry, such pesticides may also be neurotoxic to humans. Concerns have been raised that the developing brain may be particularly vulnerable to adverse effects of neurotoxic pesticides. Current requirements for safety testing do not include developmental neurotoxicity. We therefore undertook a systematic evaluation of published evidence on neurotoxicity of pesticides in current use, with specific emphasis on risks during early development. Epidemiologic studies show associations with neurodevelopmental deficits, but mainly deal with mixed exposures to pesticides. Laboratory experimental studies using model compounds suggest that many pesticides currently used in Europe--including organophosphates, carbamates, pyrethroids, ethylenebisdithiocarbamates, and chlorophenoxy herbicides--can cause neurodevelopmental toxicity. Adverse effects on brain development can be severe and irreversible. Prevention should therefore be a public health priority. The occurrence of residues in food and other types of human exposures should be prevented with regard to the pesticide groups that are known to be neurotoxic. For other substances, given their widespread use and the unique vulnerability of the developing brain, the general lack of data on developmental neurotoxicity calls for investment in targeted research. While awaiting more definite evidence, existing uncertainties should be considered in light of the need for precautionary action to protect brain development.
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Affiliation(s)
- Marina Bjørling-Poulsen
- Department of Environmental Medicine, University of Southern Denmark, Winslowparken 17, 5000 Odense, Denmark
| | - Helle Raun Andersen
- Department of Environmental Medicine, University of Southern Denmark, Winslowparken 17, 5000 Odense, Denmark
| | - Philippe Grandjean
- Department of Environmental Medicine, University of Southern Denmark, Winslowparken 17, 5000 Odense, Denmark
- Department of Environmental Health, Harvard School of Public Health, Landmark Building 3E-110, 401 Park Drive, Boston, MA 02215, USA
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Eaton DL, Daroff RB, Autrup H, Bridges J, Buffler P, Costa LG, Coyle J, McKhann G, Mobley WC, Nadel L, Neubert D, Schulte-Hermann R, Spencer PS. Review of the Toxicology of Chlorpyrifos With an Emphasis on Human Exposure and Neurodevelopment. Crit Rev Toxicol 2008; 38 Suppl 2:1-125. [PMID: 18726789 DOI: 10.1080/10408440802272158] [Citation(s) in RCA: 422] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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35
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Slotkin TA, Ryde IT, Levin ED, Seidler FJ. Developmental neurotoxicity of low dose diazinon exposure of neonatal rats: effects on serotonin systems in adolescence and adulthood. Brain Res Bull 2008; 75:640-7. [PMID: 18355640 PMCID: PMC2322865 DOI: 10.1016/j.brainresbull.2007.10.008] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Revised: 10/15/2007] [Accepted: 10/17/2007] [Indexed: 11/17/2022]
Abstract
The developmental neurotoxicity of organophosphate pesticides targets serotonin (5HT) systems, which are involved in emotional and appetitive behaviors. We exposed neonatal rats to daily doses of diazinon on postnatal days 1-4, using doses (0.5 or 2mg/kg) spanning the threshold for barely-detectable cholinesterase inhibition. We then evaluated the effects on 5HT(1A) and 5HT(2) receptors, and on the 5HT transporter in cerebral cortical regions and the brainstem in adolescence through adulthood. Diazinon evoked a lasting deficit in 5HT(1A) receptors in males only, whereas it caused a small but significant increase in 5HT transporters in females; neither effect showed a significant regional selectivity. This pattern differed substantially from that seen in earlier work with another organophosphate, chlorpyrifos, which at pharmacodynamically similar doses spanning the threshold for cholinesterase inhibition, evoked a much more substantial, global upregulation of 5HT receptor expression; with chlorpyrifos, effects on receptors were seen in females, albeit to a lesser extent than in males, and were also regionally distinct. The effects of diazinon were nonmonotonic, showing larger alterations at the lower dose, likely reflecting positive trophic effects of cholinergic stimulation once the threshold for cholinesterase inhibition is exceeded. Our results reinforce the idea that different organophosphates have fundamentally distinct effects on the developmental trajectories of specific neurotransmitter systems, unrelated to their shared action as cholinesterase inhibitors. The effects on 5HT circuits expand the scope of behavioral endpoints that need to be considered in evaluating the developmental neurotoxicity of organophosphates.
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Affiliation(s)
- Theodore A Slotkin
- Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
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36
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Sachana M, Flaskos J, Sidiropoulou E, Yavari CA, Hargreaves AJ. Inhibition of extension outgrowth in differentiating rat C6 glioma cells by chlorpyrifos and chlorpyrifos oxon: effects on microtubule proteins. Toxicol In Vitro 2008; 22:1387-91. [PMID: 18417317 DOI: 10.1016/j.tiv.2008.02.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Revised: 02/19/2008] [Accepted: 02/27/2008] [Indexed: 11/29/2022]
Abstract
The aim of this work was to assess the toxic effects of the phosphorothionate insecticide chlorpyrifos (CPF) and its major in vivo metabolite chlorpyrifos oxon (CPO) on differentiating rat C6 glioma cells. At sublethal concentrations (1-10 microM), both compounds were able to inhibit the development of extensions from C6 cells induced to differentiate by sodium butyrate. Western blot analysis of C6 cell lysates revealed that 4 h exposure to CPF was associated with decreased levels of the cytoskeletal protein MAP1B compared to controls, whereas the levels of the cytoskeletal proteins tubulin and MAP2c were not significantly affected. Western blot analysis of extracts of cells treated with CPO showed a significant, concentration-dependent decrease in the levels of tubulin after 24 h. MAP-1B levels were also significantly decreased. The above changes were not temporally related to acetylcholinesterase (AChE) inhibition. These results suggest that both CPF and CPO can exert toxic effects directly on glial cell differentiation and that the latter compound has a potent effect on the microtubule network.
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Affiliation(s)
- M Sachana
- Laboratory of Biochemistry and Toxicology, School of Veterinary Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
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Abou-Donia MB, Goldstein LB, Bullman S, Tu T, Khan WA, Dechkovskaia AM, Abdel-Rahman AA. Imidacloprid induces neurobehavioral deficits and increases expression of glial fibrillary acidic protein in the motor cortex and hippocampus in offspring rats following in utero exposure. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2008; 71:119-30. [PMID: 18080902 DOI: 10.1080/15287390701613140] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Imidacloprid, a neonicotinoid, is one of the fastest growing insecticides in use worldwide because of its selectivity for insects. The potential for neurotoxicity following in utero exposure to imidacloprid is not known. Timed pregnant Sprague-Dawley rats (300-350 g) on d 9 of gestation were treated with a single intraperitoneal injection (i.p.) of imidacloprid (337 mg/kg, 0.75 x LD50, in corn oil). Control rats were treated with corn oil. On postnatal day (PND) 30, all male and female offspring were evaluated for (a) acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activity, (b) ligand binding for nicotinic acetylcholine receptors (nAChR) and muscarinic acetylcholine receptors (m2 mAChR), (c) sensorimotor performance (inclined plane, beam-walking, and forepaw grip), and (d) pathological alterations in the brain (using cresyl violet and glial fibrillary acidic protein [GFAP] immunostaining). The offspring of treated mothers exhibited significant sensorimotor impairments at PND 30 during behavioral assessments. These changes were associated with increased AChE activity in the midbrain, cortex and brainstem (125-145% increase) and in plasma (125% increase). Ligand binding densities for [3H]cytosine for alpha4beta2 type nAchR did not show any significant change, whereas [3H]AFDX 384, a ligand for m2mAChR, was significantly increased in the cortex of offspring (120-155% increase) of imidacloprid-treated mothers. Histopathological evaluation using cresyl violet staining did not show any alteration in surviving neurons in various brain regions. On the other hand, there was a rise in GFAP immunostaining in motor cortex layer III, CA1, CA3, and the dentate gyrus subfield of the hippocampus of offspring of imidacloprid-treated mothers. The results indicate that gestational exposure to a single large, nonlethal, dose of imidacloprid produces significant neurobehavioral deficits and an increased expression of GFAP in several brain regions of the offspring on PND 30, corresponding to a human early adolescent age. These changes may have long-term adverse health effects in the offspring.
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Affiliation(s)
- Mohamed B Abou-Donia
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.
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38
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Slotkin TA, Seidler FJ. Comparative developmental neurotoxicity of organophosphates in vivo: transcriptional responses of pathways for brain cell development, cell signaling, cytotoxicity and neurotransmitter systems. Brain Res Bull 2007; 72:232-74. [PMID: 17452286 PMCID: PMC1945108 DOI: 10.1016/j.brainresbull.2007.01.005] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Revised: 12/15/2006] [Accepted: 01/09/2007] [Indexed: 11/17/2022]
Abstract
Organophosphates affect mammalian brain development through a variety of mechanisms beyond their shared property of cholinesterase inhibition. We used microarrays to characterize similarities and differences in transcriptional responses to chlorpyrifos and diazinon, assessing defined gene groupings for the pathways known to be associated with the mechanisms and/or outcomes of chlorpyrifos-induced developmental neurotoxicity. We exposed neonatal rats to daily doses of chlorpyrifos (1mg/kg) or diazinon (1 or 2mg/kg) on postnatal days 1-4 and evaluated gene expression profiles in brainstem and forebrain on day 5; these doses produce little or no cholinesterase inhibition. We evaluated pathways for general neural cell development, cell signaling, cytotoxicity and neurotransmitter systems, and identified significant differences for >60% of 252 genes. Chlorpyrifos elicited major transcriptional changes in genes involved in neural cell growth, development of glia and myelin, transcriptional factors involved in neural cell differentiation, cAMP-related cell signaling, apoptosis, oxidative stress, excitotoxicity, and development of neurotransmitter synthesis, storage and receptors for acetylcholine, serotonin, norepinephrine and dopamine. Diazinon had similar effects on many of the same processes but also showed major differences from chlorpyrifos. Our results buttress the idea that different organophosphates target multiple pathways involved in neural cell development but also that they deviate in key aspects that may contribute to disparate neurodevelopmental outcomes. Equally important, these pathways are compromised at exposures that are unrelated to biologically significant cholinesterase inhibition and its associated signs of systemic toxicity. The approach used here demonstrates how planned comparisons with microarrays can be used to screen for developmental neurotoxicity.
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Affiliation(s)
- Theodore A Slotkin
- Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
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Weselak M, Arbuckle TE, Foster W. Pesticide exposures and developmental outcomes: the epidemiological evidence. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2007; 10:41-80. [PMID: 18074304 DOI: 10.1080/10937400601034571] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Since the advent of DDT as an insecticide in the late 1930s, billions of kilograms of pesticide active ingredient have been sold in North America and around the world. In recent years, there has been a heightened public awareness of pesticides and child health and a number of epidemiologic studies linked pre- and postnatal exposures to pesticides to a number of adverse developmental outcomes, including fetal death, intrauterine growth restriction, preterm birth, and birth defects. Given this, it was felt prudent to critically appraise the evidence for periconceptual pesticide exposures and developmental outcomes. The epidemiological evidence for specific pesticide classes, families, and active ingredients were examined and summarized and recommendations were made for how to improve future studies in order to address the current pitfalls and gaps in the studies in this area. Many of the studies suffered from poor exposure estimation, relying on job title only and/or the exposure category "any pesticide" as a measure of exposure, and there was limited or inadequate evidence to support causality for all associations examined.
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Affiliation(s)
- M Weselak
- OMNI Research Group, Ottawa Hospital Research Institute, Ottawa, Ontaria.
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Mense SM, Sengupta A, Lan C, Zhou M, Bentsman G, Volsky DJ, Whyatt RM, Perera FP, Zhang L. The common insecticides cyfluthrin and chlorpyrifos alter the expression of a subset of genes with diverse functions in primary human astrocytes. Toxicol Sci 2006; 93:125-35. [PMID: 16790487 DOI: 10.1093/toxsci/kfl046] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Given the widespread use of insecticides in the environment, it is important to perform studies evaluating their potential effects on humans. Organophosphate insecticides, such as chlorpyrifos, are being phased out; however, the use of pyrethroids in household pest control is increasing. While chlorpyrifos is relatively well studied, much less is known about the potential neurotoxicity of cyfluthrin and other pyrethroids. To gain insights into the neurotoxicity of cyfluthrin, we compared and evaluated the toxicity profiles of chlorpyrifos and cyfluthrin in primary human fetal astrocytes. We found that at the same concentrations, cyfluthrin exerts as great as, or greater toxic effects on the growth, survival, and proper functioning of human astrocytes. By using microarray gene expression profiling, we systematically identified and compared the potential molecular targets of chlorpyrifos and cyfluthrin, at a genome-wide scale. We found that chlorpyrifos and cyfluthrin affect a similar number of transcripts. These targets include molecular chaperones, signal transducers, transcriptional regulators, transporters, and those involved in behavior and development. Further computational and biochemical analyses show that cyfluthrin and chlorpyrifos upregulate certain targets of the interferon-gamma and insulin-signaling pathways and that they increase the protein levels of activated extracellular signal-regulated kinase 1/2, a key component of insulin signaling; interleukin 6, a key inflammatory mediator; and glial fibrillary acidic protein, a marker of inflammatory astrocyte activation. These results suggest that inflammatory activation of astrocytes might be an important mechanism underlying neurotoxicity of both chlorpyrifos and cyfluthrin.
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Affiliation(s)
- Sarah M Mense
- Department of Environmental Health Sciences, Columbia University, Mailman School of Public Health, New York, New York 10032, USA
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41
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Betancourt AM, Burgess SC, Carr RL. Effect of developmental exposure to chlorpyrifos on the expression of neurotrophin growth factors and cell-specific markers in neonatal rat brain. Toxicol Sci 2006; 92:500-6. [PMID: 16675515 DOI: 10.1093/toxsci/kfl004] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Chlorpyrifos (CPS), a known neurotoxicant, is a widely used agricultural organophosphorus insecticide. The effects of postnatal exposure to CPS on the expression of mRNA for two factors critical to brain development, nerve growth factor (NGF) and reelin, were investigated in the forebrain of rats. In addition, the expression of mRNA for the muscarinic acetylcholine receptor (mAChR) M(1) subtype and cell-specific markers for developing neurons (beta-III tubulin), astrocytes (glial fibrillary acidic protein, GFAP), and oligodendrocytes (myelin-associated glycoprotein, MAG) was also investigated. Oral administration of CPS (1.5 or 3.0 mg/kg) or the corn oil vehicle was performed daily from postnatal days (PNDs) 1 through 6. No signs of overt toxicity or of cholinergic hyperstimulation were observed after CPS administration. Body weight was significantly different from controls on PND7 in both males and females exposed to 3.0 mg/kg CPS. Quantitative PCR was performed on the forebrain. The expression of NGF, reelin, and M(1) mAChR mRNA was significantly reduced with both dosages of CPS in both sexes. beta-III Tubulin mRNA expression remained unchanged after exposure, whereas MAG mRNA expression was significantly decreased with both dosages of CPS in both sexes, suggesting effects on the developing oligodendrocytes. In contrast, GFAP mRNA levels were significantly increased with both dosages of CPS in both sexes, suggesting increased astrocyte reactivity. Our findings indicate that dosages of CPS which cause significant cholinesterase inhibition but do not exert overt toxicity can adversely affect the expression levels of critical genes involved in brain development during the early postnatal period in the rat.
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Affiliation(s)
- Angela M Betancourt
- Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, 39762, USA
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42
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Abou-Donia MB, Khan WA, Dechkovskaia AM, Goldstein LB, Bullman SL, Abdel-Rahman A. In utero exposure to nicotine and chlorpyrifos alone, and in combination produces persistent sensorimotor deficits and Purkinje neuron loss in the cerebellum of adult offspring rats. Arch Toxicol 2006; 80:620-31. [PMID: 16482470 DOI: 10.1007/s00204-006-0077-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Accepted: 12/23/2005] [Indexed: 10/25/2022]
Abstract
This study was carried out to investigate the effect of in utero exposure to the cholinotoxicants, nicotine and chlorpyrifos, alone or in combination on neurobehavioral alterations and neuronal morphology latter in adult age. In the present study, 90 days old (corresponding to a human adult age) male and female offspring rats were evaluated for neurobehavioral, and neuropathological alterations following maternal, gestational exposure to nicotine and chlorpyrifos (O,O-diethyl-O-3,5,6-trichloro-2-pyridinyl phosphorothioate), alone and in combination. Female Sprague-Dawley rats (300-350 g) with timed-pregnancy were treated with nicotine (3.3 mg/kg/day, in bacteriostatic water via s.c. implantation of mini osmotic pump), chlorpyrifos (1.0 mg/kg, daily, dermal, in 75% ethanol, 1.0 ml/kg) or a combination of both chemicals, on gestational days (GD) 4-20. Control animals received bacteriostatic water via s.c. implantation of mini osmotic pump and dermal application of 70% ethanol. The offspring at postnatal day (PND) 90 were evaluated for neurobehavioral performance, changes in the activity of plasma butyrylcholinesterase (BChE) and acetylcholinesterase (AChE), and neuropathological alterations in the brain. Neurobehavioral evaluations included beam-walk score, beam-walk time, incline plane performance and forepaw grip time. Male and female offspring from mothers treated with nicotine and CPF, alone or in combination showed impairments in the performance of neurobehavioral tests, indicating sensorimotor deficits. Female offspring from mothers treated with a combination of nicotine and chlorpyrifos showed significant increase in plasma BChE activity. Brain regional AChE activity showed differential increases in male and female offspring. Brainstem and cerebellum of female offspring from mothers treated with nicotine or chlorpyrifos, alone or in combination showed increased AChE activity, whereas brainstem of male offspring from mothers treated with nicotine alone or a combination of nicotine and chlorpyrifos showed increase in AChE activity. Also, male offspring exposed in utero to nicotine exhibited increased AChE activity. Histopathological evaluations using cresyl violet staining showed a decrease in surviving Purkinje neurons in the cerebellum in offspring of all treatments groups. An increase in glial fibrillary acidic protein (GFAP) immuno-staining was observed in cerebellum white matter as well as granular cell layer (GCL) of cerebellum following all exposures. These results indicate that in utero exposure to nicotine and chlorpyrifos, alone and in combination produced significant sensorimotor deficits in male and female offspring, differential increase in brain AChE activity, a decrease in the surviving neurons and an increased expression of GFAP in cerebellum in adult offspring rats at a corresponding human adult age. Collectively, this study demonstrates that maternal exposure to environmental neurotoxic chemicals, i.e., nicotine and chlorpyrifos leads to developmental abnormalities in the offspring that persist latter into adulthood.
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Affiliation(s)
- Mohamed B Abou-Donia
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
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43
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Colborn T. A case for revisiting the safety of pesticides: a closer look at neurodevelopment. ENVIRONMENTAL HEALTH PERSPECTIVES 2006; 114:10-7. [PMID: 16393651 PMCID: PMC1332649 DOI: 10.1289/ehp.7940] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The quality and quantity of the data about the risk posed to humans by individual pesticides vary considerably. Unlike obvious birth defects, most developmental effects cannot be seen at birth or even later in life. Instead, brain and nervous system disturbances are expressed in terms of how an individual behaves and functions, which can vary considerably from birth through adulthood. In this article I challenge the protective value of current pesticide risk assessment strategies in light of the vast numbers of pesticides on the market and the vast number of possible target tissues and end points that often differ depending upon timing of exposure. Using the insecticide chlorpyrifos as a model, I reinforce the need for a new approach to determine the safety of all pesticide classes. Because of the uncertainty that will continue to exist about the safety of pesticides, it is apparent that a new regulatory approach to protect human health is needed.
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Affiliation(s)
- Theo Colborn
- University of Florida, Gainesville, Florida, and TEDX (The Endocrine Disruption Exchange) Inc., Paonia, Colorado 81428, USA.
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44
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Malkiewicz K, Koteras M, Folkesson R, Brzezinski J, Winblad B, Szutowski M, Benedikz E. Cypermethrin alters Glial Fibrillary Acidic Protein levels in the rat brain. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2006; 21:51-55. [PMID: 21783638 DOI: 10.1016/j.etap.2005.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Accepted: 06/18/2005] [Indexed: 05/31/2023]
Abstract
Pyrethroids, widely used insecticides, are biologically active in neurons. Whether they act on the non-neuronal brain cells remains an open question. Thus, the aim of this study was to examine whether Cypermethrin intoxication affects astroglial cells in the rat brain. The levels of Glial Fibrillary Acidic Protein (GFAP) in different brain regions were measured by ELISA following oral treatment with 5 or 10% of LD(50) of Cypermethrin per day for 6 days. A significant decrease of GFAP was observed in different brain regions of treated animals. The cerebral cortex showed the most pronounced effect with GFAP levels reduced to 81% of the controls 2 days after treatment and 77% 21 days after treatment. Although we did not find profound changes in the morphology of astrocytes in Cypermethrin treated animals, the decrease in GFAP suggests that astrocytes were affected by low doses of pyrethroids. The possible consequences were discussed.
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Affiliation(s)
- Katarzyna Malkiewicz
- Department of Toxicology, Medical University of Warsaw, Pharmaceutical Faculty, Warsaw, Poland; Karolinska Institutet, Neurotec, Section of Experimental Geriatrics, KFC, Novum, 141 86 Stockholm, Sweden
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45
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Guizzetti M, Pathak S, Giordano G, Costa LG. Effect of organophosphorus insecticides and their metabolites on astroglial cell proliferation. Toxicology 2005; 215:182-90. [PMID: 16102884 DOI: 10.1016/j.tox.2005.07.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2005] [Revised: 06/23/2005] [Accepted: 07/06/2005] [Indexed: 11/15/2022]
Abstract
Though little attention has been given to the possibility that glial cells may represent a target for the developmental neurotoxicity of organophosphorus (OP) insecticides, recent evidence, obtained in particular with chlorpyrifos (CP), suggests that developmental exposure to this compound may indeed target astrocytes. To substantiate and expand these observations, we carried out a series of in vitro studies utilizing fetal rat astrocytes and a human astrocytoma cell line, 1321N1 cells, to investigate the effect of the OPs CP, diazinon (DZ) and parathion (P), their oxygen analogs chlorpyrifos oxon (CPO), diazoxon (DZO) and paraoxon (PO), and their metabolites 3,5,6-trichloro-2-pyridinol (TCP), 2-isopropyl-6-methyl-4-pyrimidol (IMP) and para-nitrophenol (PNP), on cell proliferation. In fetal rat astrocytes and astrocytoma cells maintained in serum, CP, DZ, P, CPO, DZO, and PO induced a concentration-dependent inhibition in [(3)H]thymidine incorporation with a very similar potency (IC(50) between 45 and 57 microM). Among the other metabolites, PNP was the most potent (IC(50)=70-80 microM), while TCP and IMP were much less effective (IC(50)>100 microM). Cytotoxicity appears to account only for a small part of the effect on DNA synthesis. OP insecticides and their oxons were three- to six-fold more potent in inhibiting [(3)H]thymidine incorporation when cells were synchronized in the G(0)/G(1) phase of the cell cycle and re-stimulated by carbachol or epidermal growth factor. These results suggest that OP insecticides and their oxons affect astroglial cell proliferation and that the transition from the G(0)/G(1) to the S/G(2) phase of the cell cycle may be particularly sensitive to the action of these compounds.
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Affiliation(s)
- Marina Guizzetti
- Department of Environmental and Occupational Health Sciences, University of Washington, 4225 Roosevelt Way N.E. 100, Seattle, WA 98105, USA.
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Searles Nielsen S, Mueller BA, De Roos AJ, Viernes HMA, Farin FM, Checkoway H. Risk of brain tumors in children and susceptibility to organophosphorus insecticides: the potential role of paraoxonase (PON1). ENVIRONMENTAL HEALTH PERSPECTIVES 2005; 113:909-13. [PMID: 16002382 PMCID: PMC1257655 DOI: 10.1289/ehp.7680] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2004] [Accepted: 03/17/2005] [Indexed: 05/03/2023]
Abstract
Prior research suggests that childhood brain tumors (CBTs) may be associated with exposure to pesticides. Organophosphorus insecticides (OPs) target the developing nervous system, and until recently, the most common residential insecticides were chlorpyrifos and diazinon, two OPs metabolized in the body through the cytochrome P450/paraoxonase 1 (PON1) pathway. To investigate whether two common PON1 polymorphisms, C-108T and Q192R, are associated with CBT occurrence, we conducted a population-based study of 66 cases and 236 controls using DNA from neonatal screening archive specimens in Washington State, linked to interview data. The risk of CBT was nonsignificantly increased in relation to the inefficient PON1 promoter allele [per PON1(-108T) allele, relative to PON1(-108CC): odds ratio (OR) = 1.4; 95% confidence interval (CI), 1.0-2.2; p-value for trend = 0.07]. Notably, this association was strongest and statistically significant among children whose mothers reported chemical treatment of the home for pests during pregnancy or childhood (per PON1(-108T) allele: among exposed, OR = 2.6; 95% CI, 1.2-5.5; among unexposed, OR = 0.9; 95% CI, 0.5-1.6) and for primitive neuroectodermal tumors (per PON1(-108T) allele: OR = 2.4; 95% CI, 1.1-5.4). The Q192R polymorphism, which alters the structure of PON1 and influences enzyme activity in a substrate-dependent manner, was not associated with CBT risk, nor was the PON1(C-108T/Q192R) haplotype. These results are consistent with an inverse association between PON1 levels and CBT occurrence, perhaps because of PON1's ability to detoxify OPs common in children's environments. Larger studies that measure plasma PON1 levels and incorporate more accurate estimates of pesticide exposure will be required to confirm these observations.
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Affiliation(s)
- Susan Searles Nielsen
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA.
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Slotkin TA, Oliver CA, Seidler FJ. Critical periods for the role of oxidative stress in the developmental neurotoxicity of chlorpyrifos and terbutaline, alone or in combination. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2005; 157:172-80. [PMID: 15963356 DOI: 10.1016/j.devbrainres.2005.04.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2005] [Revised: 04/04/2005] [Accepted: 04/04/2005] [Indexed: 10/25/2022]
Abstract
The developmental neurotoxicity of chlorpyrifos (CPF) involves mechanisms other than inhibition of cholinesterase. In the current study, we examined the ability of CPF to evoke lipid peroxidation in the developing brain of fetal and neonatal rats. CPF given to pregnant rats on gestational days 17-20 or to neonatal rats on postnatal days 1-4, failed to elicit increases in thiobarbituric acid-reactive species (TBARS) in brain regions even when the dose was raised above the threshold for systemic toxicity and hepatic damage. In contrast, CPF administration during the second postnatal week, the peak period of neuronal cell differentiation and synaptogenesis, did evoke significant increases in TBARS even at a dose devoid of systemic toxicity. Terbutaline, which is chemically unrelated to CPF and which stimulates neuronal cell metabolism through direct actions on beta-adrenoceptors, also elicited oxidative damage in the developing brain with greater sensitivity in the second postnatal week. These results indicate that diverse compounds can exert convergent effects on brain development through their shared potential to elicit oxidative stress, and that the net outcome is dependent upon specific developmental stages in which metabolic demand is especially high. Furthermore, given the common use of terbutaline in the therapy of preterm labor, and the nearly ubiquitous exposure of the human population to organophosphorus pesticides, the combined oxidative burden of exposure to both agents may contribute to the worsened neurodevelopmental outcomes noted in animal models of such dual exposures.
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Affiliation(s)
- Theodore A Slotkin
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
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48
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Zhao Q, Gadagbui B, Dourson M. Lower birth weight as a critical effect of chlorpyrifos: A comparison of human and animal data. Regul Toxicol Pharmacol 2005; 42:55-63. [PMID: 15896443 DOI: 10.1016/j.yrtph.2005.01.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Revised: 01/14/2005] [Accepted: 01/23/2005] [Indexed: 10/25/2022]
Abstract
Chlorpyrifos is an irreversible inhibitor of cholinesterase (ChE), and inhibition of ChE is believed to be the most sensitive effect in all animal species evaluated and in humans. Recent epidemiology studies reported associations between umbilical cord plasma chlorpyrifos levels and fetal birth weight decreases among minority women living in New York City during pregnancy. These associations raise questions whether impaired fetal development is the critical effect rather than the inhibition of ChE as is currently believed so. We analyze the available information from epidemiology studies and animal studies in order to identify the relative sensitivity of decreased birth weight and inhibition of ChE from exposure to chlorpyrifos. We find that the positive associations from some epidemiology studies are different from other epidemiology investigations. Moreover, a direct comparison of experimental animal neonatal information shows that cholinesterase inhibition is a more sensitive indicator of adverse effect than reduced body weight, and that neonates are equally, or perhaps less sensitive to cholinesterase inhibition than their maternal parent. Based on a review of human studies and comparison of human cord blood chlorpyrifos concentrations with blood chlorpyrifos concentrations that in animals caused effects with good dose-response, it appears unlikely that the exposure level encountered by the population reported in [Whyatt, R.M., Rauh, V., Barr, D.B., Camann, D.E., Andrews, H.F., Garfinkel, R., Hoepner, L.A., Diaz, D., Dietrich, J., Reyes, A., Tang, D., Kinney, P.L., Perera, F.P., 2004. Prenatal insecticide exposures and birth weight and length among an urban minority cohort. Environ. Health Perspect. 112, 1125-1132.] study would cause any fetal developmental effect. Moreover, the critical effect for chlorpyrifos still appears to be cholinesterase inhibition.
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Affiliation(s)
- Qiyu Zhao
- Toxicology Excellence for Risk Assessment (TERA), 2300 Montana Ave., Suite 409, Cincinnati, OH 45211, USA
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Abdel-Rahman A, Dechkovskaia AM, Sutton JM, Chen WC, Guan X, Khan WA, Abou-Donia MB. Maternal exposure of rats to nicotine via infusion during gestation produces neurobehavioral deficits and elevated expression of glial fibrillary acidic protein in the cerebellum and CA1 subfield in the offspring at puberty. Toxicology 2005; 209:245-61. [PMID: 15795061 DOI: 10.1016/j.tox.2004.12.037] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Revised: 12/21/2004] [Accepted: 12/30/2004] [Indexed: 11/23/2022]
Abstract
Maternal smoking during pregnancy is known to be a significant contributor to developmental neurological health problems in the offspring. In animal studies, nicotine treatment via injection during gestation has been shown to produce episodic hypoxia in the developing fetus. Nicotine delivery via mini osmotic pump, while avoiding effects due to hypoxia-ischemia, it also provides a steady level of nicotine in the plasma. In the present study timed-pregnant Sprague-Dawley rats (300-350 g) were treated with nicotine (3.3 mg/kg, in bacteriostatic water via s.c. implantation of mini osmotic pump) from gestational days (GD) 4-20. Control animals were treated with bacteriostatic water via s.c. implantation of mini osmotic pump. Offspring on postnatal day (PND) 30 and 60, were evaluated for changes in the ligand binding for various types of nicotinic acetylcholine receptors and neuropathological alterations. Neurobehavioral evaluations for sensorimotor functions, beam-walk score, beam-walk time, incline plane and grip time response were carried out on PND 60 offspring. Beam-walk time and forepaw grip time showed significant impairments in both male and female offspring. Ligand binding densities for [3H]epibatidine, [3H]cytisine and [3H]alpha-bungarotoxin did not show any significant changes in nicotinic acetylcholine receptors subtypes in the cortex at PND 30 and 60. Histopathological evaluation using cresyl violet staining showed significant decrease in surviving Purkinje neurons in the cerebellum and a decrease in surviving neurons in the CA1 subfield of hippocampus on PND 30 and 60. An increase in glial fibrillary acidic protein (GFAP) immuno-staining was observed in cerebellum white matter as well as granular cell layer of cerebellum and the CA1 subfield of hippocampus on PND 30 and 60 of both male and female offspring. These results indicate that maternal exposure to nicotine produces significant neurobehavioral deficits, a decrease in the surviving neurons and an increased expression of GFAP in cerebellum and CA1 subfield of hippocampus of the offspring on PND 30 and 60. The results show that although 60-day-old male and female rat offspring of mothers exposed to nicotine during gestation did not differ from control in body weight gain or nicotinic acetylcholine receptors ligand binding, they exhibited significant sensorimotor deficits that were consistent with the neuropathological alterations seen in the brain. These neurobehavioral and pathological deficits indicate that maternal nicotine exposure may produce long-term adverse health effects in the offspring.
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Affiliation(s)
- Ali Abdel-Rahman
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
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Brimijoin S. Can cholinesterase inhibitors affect neural development? ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2005; 19:429-432. [PMID: 21783508 DOI: 10.1016/j.etap.2004.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Accumulating evidence supports the view that acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) can influence the proliferation and differentiation of nerve cells. AChE in particular has been found to promote neurite outgrowth in a variety of model systems, possibly by serving as an adhesion molecule. Thus one might suspect that cholinesterase inhibitors would disturb neuronal development, with long-term implications for structure and function in the central and peripheral nervous systems. The actual picture is more complex because AChE's effects on neurite outgrowth may reflect protein-protein interactions that are not directly related to catalytic function but are nonetheless influenced by ligands with special structural features. The putative structural interactions have not yet been rigorously defined, but they are likely to involve enzyme regions at or near the peripheral anionic site. In addition to such effects, some organophosphorus anticholinesterases have been reported to act by still other mechanisms to depress macromolecule synthesis and cell survival in the developing brain. Taken together, this emerging information highlights the potential importance of anticholinesterase agents in developmental neurotoxicology.
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Affiliation(s)
- Stephen Brimijoin
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, 200 First Street, S.W., Rochester, MN 55905, USA
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