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Schneider JS. Response to "Comment on 'Neurotoxicity and Outcomes from Developmental Lead Exposure: Persistent or Permanent?'". ENVIRONMENTAL HEALTH PERSPECTIVES 2024; 132:48002. [PMID: 38607983 PMCID: PMC11014070 DOI: 10.1289/ehp14978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 03/20/2024] [Indexed: 04/14/2024]
Affiliation(s)
- Jay S. Schneider
- Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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Schneider JS. Neurotoxicity and Outcomes from Developmental Lead Exposure: Persistent or Permanent? ENVIRONMENTAL HEALTH PERSPECTIVES 2023; 131:85002. [PMID: 37639477 PMCID: PMC10461788 DOI: 10.1289/ehp12371] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 05/08/2023] [Accepted: 08/02/2023] [Indexed: 08/31/2023]
Abstract
BACKGROUND Childhood lead poisoning remains an important public health issue in the United States, as well as elsewhere in the world. Although primary prevention is a major goal and it is critically important to keep children from getting poisoned, it is also important to explore ways to reduce the neurotoxic effects of lead in those children already poisoned. Whether lead-induced neurotoxicity and its related adverse outcomes are viewed as "permanent" or "persistent" may influence the way in which potential remediation efforts are considered for improving outcomes from childhood lead poisoning. OBJECTIVES The objective of this commentary was to discuss the ideas of permanence and persistence in relation to the direct neurotoxic effects of lead on the brain and the resulting adverse outcomes from these effects. Recent new insights regarding potential mitigation of lead-induced neurotoxic effects on brain and behavior are considered along with clinical information on neurorehabilitation to suggest potential strategies for improving cognitive/behavioral outcomes in lead-poisoned children. DISCUSSION The distinction between permanent and persistent in regard to lead-induced neurotoxicity and its resulting outcomes may have broad implications for public health policies in response to the problem of childhood lead exposure. The term permanent implies that the damage is irreversible with little chance of improvement. However, there is evidence that at least some of the adverse cognitive/behavioral outcomes from lead exposure are persistent rather than permanent and potentially amenable, under the appropriate circumstances, to some level of mitigation. This author recommends that clinical, interventional research efforts be devoted to exploring optimal neurorehabilitative and enrichment conditions to stimulate plasticity and enhance functioning to determine the extent to which promising results from preclinical studies of lead-induced brain damage and the mitigation of these effects can be successfully translated to humans. https://doi.org/10.1289/EHP12371.
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Affiliation(s)
- Jay S. Schneider
- Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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Frndak S, Barg G, Queirolo EI, Mañay N, Colder C, Yu G, Ahmed Z, Kordas K. Do Neighborhood Factors Modify the Effects of Lead Exposure on Child Behavior? TOXICS 2022; 10:517. [PMID: 36136482 PMCID: PMC9504847 DOI: 10.3390/toxics10090517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 06/16/2023]
Abstract
Lead exposure and neighborhoods can affect children’s behavior, but it is unclear if neighborhood characteristics modify the effects of lead on behavior. Understanding these modifications has important intervention implications. Blood lead levels (BLLs) in children (~7 years) from Montevideo, Uruguay, were categorized at 2 µg/dL. Teachers completed two behavior rating scales (n = 455). At one-year follow-up (n = 380), caregivers reported child tantrums and parenting conflicts. Multilevel generalized linear models tested associations between BLLs and behavior, with neighborhood disadvantage, normalized difference vegetation index (NDVI), and distance to nearest greenspace as effect modifiers. No effect modification was noted for neighborhood disadvantage or NDVI. Children living nearest to greenspace with BLLs < 2 µg/dL were lower on behavior problem scales compared to children with BLLs ≥ 2 µg/dL. When furthest from greenspace, children were similar on behavior problems regardless of BLL. The probability of daily tantrums and conflicts was ~20% among children with BLLs < 2 µg/dL compared to ~45% among children with BLLs ≥ 2 µg/dL when closest to greenspace. Furthest from greenspace, BLLs were not associated with tantrums and conflicts. Effect modification of BLL on child behavior by distance to greenspace suggests that interventions should consider both greenspace access and lead exposure prevention.
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Affiliation(s)
- Seth Frndak
- Department of Epidemiology and Environmental Health, University at Buffalo—State University of New York, New York, NY 14203, USA
| | - Gabriel Barg
- Department of Neuroscience and Learning, Catholic University of Uruguay, Montevideo 11600, Uruguay
| | - Elena I. Queirolo
- Department of Neuroscience and Learning, Catholic University of Uruguay, Montevideo 11600, Uruguay
| | - Nelly Mañay
- Faculty of Chemistry, University of the Republic of Uruguay (UDELAR), Montevideo 11600, Uruguay
| | - Craig Colder
- Department of Psychology, University at Buffalo—State University of New York, New York, NY 14214, USA
| | - Guan Yu
- Department of Biostatistics, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Zia Ahmed
- Research and Education in Energy, Environment and Water (RENEW) Institute, University at Buffalo—State University of New York, New York, NY 14260, USA
| | - Katarzyna Kordas
- Department of Epidemiology and Environmental Health, University at Buffalo—State University of New York, New York, NY 14203, USA
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Altered genome-wide hippocampal gene expression profiles following early life lead exposure and their potential for reversal by environmental enrichment. Sci Rep 2022; 12:11937. [PMID: 35879375 PMCID: PMC9314447 DOI: 10.1038/s41598-022-15861-9] [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: 08/05/2021] [Accepted: 06/30/2022] [Indexed: 12/02/2022] Open
Abstract
Early life lead (Pb) exposure is detrimental to neurobehavioral development. The quality of the environment can modify negative influences from Pb exposure, impacting the developmental trajectory following Pb exposure. Little is known about the molecular underpinnings in the brain of the interaction between Pb and the quality of the environment. We examined relationships between early life Pb exposure and living in an enriched versus a non-enriched postnatal environment on genome-wide transcription profiles in hippocampus CA1. RNA-seq identified differences in the transcriptome of enriched vs. non-enriched Pb-exposed animals. Most of the gene expression changes associated with Pb exposure were reversed by enrichment. This was also true for changes in upstream regulators, splicing events and long noncoding RNAs. Non-enriched rats also had memory impairments; enriched rats had no deficits. The results demonstrate that an enriched environment has a profound impact on behavior and the Pb-modified CA1 transcriptome. These findings show the potential for interactions between Pb exposure and the environment to result in significant transcriptional changes in the brain and, to the extent that this may occur in Pb-exposed children, could influence neuropsychological/educational outcomes, underscoring the importance for early intervention and environmental enrichment for Pb-exposed children.
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Abstract
INTRODUCTION The syndromes of mild cognitive impairment (MCI) or mild neurocognitive disorder (MiND), often prodromal to dementia (Major Neurocognitive Disorder), are characterized by acquired clinically significant changes in one or more cognitive domains despite preserved independence. Mild impairment has significant medicolegal consequences for an affected person and their care system. We review the more common etiologies of MiND and provide a systematic review of its medicolegal implications. METHODS We conducted a systematic review of the peer-reviewed English literature on medicolegal aspects of MCI or MiND using comprehensive search terms and expanding our review to include sources cited by these reports. RESULTS Impairment of memory, executive function, social cognition, judgment, insight or abstraction can alter an individual's abilities in a variety of areas that include decision making, informed consent, designation of a surrogate decision-maker such as a health care proxy, understanding and management of financial affairs, execution of a will, or safe driving. CONCLUSION Even mild cognitive impairment can have significant behavioral consequences. Clinicians can assist care partners and persons with MCI or MiND by alerting them to the medicolegal concerns that often accompany cognitive decline. Early recognition and discussion can help a care system manage medicolegal risk more effectively and promote thoughtful advance planning.
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Affiliation(s)
- Anca Bejenaru
- Department of Psychiatry and Behavioral Health, Christiana Care, Wilmington, DE, USA
| | - James M Ellison
- Department of Psychiatry and Behavioral Health, Christiana Care, Wilmington, DE, USA.,Department of Family and Community Medicine, Christiana Care, Wilmington, DE, USA.,Department of Psychiatry & Human Behavior, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
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Jacobs B, Rally H, Doyle C, O'Brien L, Tennison M, Marino L. Putative neural consequences of captivity for elephants and cetaceans. Rev Neurosci 2021; 33:439-465. [PMID: 34534428 DOI: 10.1515/revneuro-2021-0100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/02/2021] [Indexed: 12/20/2022]
Abstract
The present review assesses the potential neural impact of impoverished, captive environments on large-brained mammals, with a focus on elephants and cetaceans. These species share several characteristics, including being large, wide-ranging, long-lived, cognitively sophisticated, highly social, and large-brained mammals. Although the impact of the captive environment on physical and behavioral health has been well-documented, relatively little attention has been paid to the brain itself. Here, we explore the potential neural consequences of living in captive environments, with a focus on three levels: (1) The effects of environmental impoverishment/enrichment on the brain, emphasizing the negative neural consequences of the captive/impoverished environment; (2) the neural consequences of stress on the brain, with an emphasis on corticolimbic structures; and (3) the neural underpinnings of stereotypies, often observed in captive animals, underscoring dysregulation of the basal ganglia and associated circuitry. To this end, we provide a substantive hypothesis about the negative impact of captivity on the brains of large mammals (e.g., cetaceans and elephants) and how these neural consequences are related to documented evidence for compromised physical and psychological well-being.
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Affiliation(s)
- Bob Jacobs
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Colorado College, Colorado Springs, CO, 80903, USA
| | - Heather Rally
- Foundation to Support Animal Protection, Norfolk, VA, 23510, USA
| | - Catherine Doyle
- Performing Animal Welfare Society, P.O. Box 849, Galt, CA, 95632, USA
| | - Lester O'Brien
- Palladium Elephant Consulting Inc., 2408 Pinewood Dr. SE, Calgary, AB, T2B1S4, Canada
| | - Mackenzie Tennison
- Department of Psychology, University of Washington, Seattle, WA, 98195, USA
| | - Lori Marino
- Whale Sanctuary Project, Kanab, UT, 84741, USA
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de Lima Junior NC, Camilo JF, do Carmo PR, de Andrade MN, Braz BF, Santelli RE, de Brito Gitirana L, Ferreira ACF, de Carvalho DP, Miranda-Alves L, Dias GRM. Subacute exposure to lead promotes disruption in the thyroid gland function in male and female rats. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 274:115889. [PMID: 33223335 DOI: 10.1016/j.envpol.2020.115889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 06/11/2023]
Abstract
Exposure to heavy metals, such as lead, is a global public health problem. Lead has a long historic relation to several adverse health conditions and was recently classified as an endocrine disruptor. The aim of this study was to investigate the effects of subacute exposure to lead on the thyroid gland function. Adult male and female Wistar rats received a lead acetate solution containing 10 or 25 mg/kg, by gavage, three times a week, for 14 days. One week later, behavioral testing showed no alterations in anxiety and motor-exploratory parameters, as evaluated by Open-Field and Plus-Maze Tests, but impairment in learning and memory was found in the male 25 mg/kg lead-treated group and in both female lead-treated groups, as evaluated by the Inhibitory Avoidance Test. After one week, serum levels of tT3 were reduced in the 25 mg/kg female group and in the 10 mg∕ kg male group. However, tT4 levels were increased in the 25 mg/kg male group and in both female treated groups. TSH levels did not change and lead serum levels were undetectable. Morphologic alterations were observed in the thyroid gland, including abnormal thyroid parenchyma follicles of different sizes, epithelial stratification and vacuolization of follicular cells, decrease in colloid eosinophilia and vascular congestion, accompanied by morphometric alterations. An increase in collagen deposition was also observed. No differences were observed in TPO activity or protein expression, H2O2 generation by NADPH oxidases or hepatic D1 mRNA expression. However, thyroid NIS protein expression was considerably decreased in the male and female lead-treated groups, while TSHr expression was decreased in the 25 mg/kg female lead-treated group. These findings demonstrated that subacute exposure to lead acetate disrupts thyroid gland function in both sexes, leading to morphophysiological impairment and to changes in learning and memory abilities.
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Affiliation(s)
- Niedson Correia de Lima Junior
- Laboratory of Endocrine Physiology Doris Rosenthal, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Postgraduate Program in Endocrinology, Faculty of Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Juliana Franco Camilo
- Laboratory of Endocrine Physiology Doris Rosenthal, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Pâmella Rodrigues do Carmo
- Laboratory of Endocrine Physiology Doris Rosenthal, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Marcelle Novaes de Andrade
- Laboratory of Endocrine Physiology Doris Rosenthal, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Postgraduate Program in Pharmacology and Medicinal Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Bernardo Ferreira Braz
- Department of Analytical Chemistry, Institute of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Ricardo Erthal Santelli
- Department of Analytical Chemistry, Institute of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Lycia de Brito Gitirana
- Laboratory of Integrative Histology, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Andrea Claudia Freitas Ferreira
- Laboratory of Endocrine Physiology Doris Rosenthal, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Postgraduate Program in Endocrinology, Faculty of Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Denise Pires de Carvalho
- Laboratory of Endocrine Physiology Doris Rosenthal, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Postgraduate Program in Endocrinology, Faculty of Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Leandro Miranda-Alves
- Laboratory of Endocrine Physiology Doris Rosenthal, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Postgraduate Program in Endocrinology, Faculty of Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Postgraduate Program in Pharmacology and Medicinal Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Glaecir Roseni Mundstock Dias
- Laboratory of Endocrine Physiology Doris Rosenthal, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Postgraduate Program in Endocrinology, Faculty of Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
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Hernández-Plata I, Rodríguez VM, Tovar-Sánchez E, Carrizalez L, Villalobos P, Mendoza-Trejo MS, Mussali-Galante P. Metal brain bioaccumulation and neurobehavioral effects on the wild rodent Liomys irroratus inhabiting mine tailing areas. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:36330-36349. [PMID: 32556984 DOI: 10.1007/s11356-020-09451-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 05/26/2020] [Indexed: 06/11/2023]
Abstract
Ecotoxicological studies are necessary in order to evaluate the effects of environmental exposure of chemicals on wild animals and their ecological consequences. Particularly, neurobehavioral effects of heavy metal elements on wild rodents have been scarcely investigated. In the present study, we analyzed the effect of metal bioaccumulation (Pb, As, Mg, Ni, and Zn) in the brain and in the liver on exploratory activity, learning, memory, and on some dopaminergic markers in the wild rodent Liomys irroratus living inside mine tailings, at Huautla, Morelos, Mexico. We found higher Pb concentration but lower Zn in striatum, nucleus accumbens, midbrain, and hippocampus in exposed animals in comparison to rodents from the reference site. Exposed rodents exhibited anxious behavior evaluated in the open field, while no alterations in learning were found. However, they displayed slight changes in the memory test in comparison to reference group. The neurochemical evaluation showed higher levels of dopamine and 5-hydroxyindolacetic acid in midbrain, while lower levels of metabolites dihydroxyphenyl acetic acid and homovanillic acid in striatum of exposed rodents. In addition, mRNA expression levels of dopaminergic D2 receptors in nucleus accumbens were lower in animals from the mining zone than in animals from the reference zone. This is the first study that shows that chronic environmental exposure to metals results in behavioral and neurochemical alterations in the wild rodent L. irroratus, a fact that may comprise the survival of the individuals resulting in long-term effects at the population level. Finally, we suggest the use of L. irroratus as a sentinel species for environmental biomonitoring of mining sites.
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Affiliation(s)
- Isela Hernández-Plata
- Laboratorio de Investigaciones Ambientales, Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, Cuernavaca, Morelos, México
| | - Verónica M Rodríguez
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Querétaro, Querétaro, 76230, México
| | - Efraín Tovar-Sánchez
- Centro de Investigación para la Biodiversidad y Conservación, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, Cuernavaca, Morelos, México
| | - Leticia Carrizalez
- Coordinación para la Innovación y Aplicación de la Ciencia y la Tecnología, Universidad Autónoma de San Luis Potosí, Av. Sierra Leona #550, Col. Lomas 2a Sección, 78210, San Luis Potosí, San Luis Potosí, México
| | - Patricia Villalobos
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Querétaro, Querétaro, 76230, México
| | - María Soledad Mendoza-Trejo
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Querétaro, Querétaro, 76230, México
| | - Patricia Mussali-Galante
- Laboratorio de Investigaciones Ambientales, Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, Cuernavaca, Morelos, México.
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Marshall AT, Betts S, Kan EC, McConnell R, Lanphear BP, Sowell ER. Association of lead-exposure risk and family income with childhood brain outcomes. Nat Med 2020; 26:91-97. [PMID: 31932788 PMCID: PMC6980739 DOI: 10.1038/s41591-019-0713-y] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 11/22/2019] [Indexed: 02/08/2023]
Abstract
Socioeconomic factors influence brain development and structure, but most studies have overlooked neurotoxic insults that impair development, such as lead exposure. Childhood lead exposure affects cognitive development at the lowest measurable concentrations, but little is known about its impact on brain development during childhood. We examined cross-sectional associations among brain structure, cognition, geocoded measures of the risk of lead exposure and sociodemographic characteristics in 9,712 9- and 10-year-old children. Here we show stronger negative associations of living in high-lead-risk census tracts in children from lower- versus higher-income families. With increasing risk of exposure, children from lower-income families exhibited lower cognitive test scores, smaller cortical volume and smaller cortical surface area. Reducing environmental insults associated with lead-exposure risk might confer greater benefit to children experiencing more environmental adversity, and further understanding of the factors associated with high lead-exposure risk will be critical for improving such outcomes in children.
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Affiliation(s)
- Andrew T Marshall
- Children's Hospital Los Angeles, and the Department of Pediatrics, University of Southern California, Los Angeles, CA, USA
| | - Samantha Betts
- Children's Hospital Los Angeles, and the Department of Pediatrics, University of Southern California, Los Angeles, CA, USA
| | - Eric C Kan
- Children's Hospital Los Angeles, and the Department of Pediatrics, University of Southern California, Los Angeles, CA, USA
| | - Rob McConnell
- Department of Preventive Medicine, University of Southern California, Los Angeles, CA, USA
| | - Bruce P Lanphear
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
| | - Elizabeth R Sowell
- Children's Hospital Los Angeles, and the Department of Pediatrics, University of Southern California, Los Angeles, CA, USA.
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Rocha A, Trujillo KA. Neurotoxicity of low-level lead exposure: History, mechanisms of action, and behavioral effects in humans and preclinical models. Neurotoxicology 2019; 73:58-80. [PMID: 30836127 PMCID: PMC7462347 DOI: 10.1016/j.neuro.2019.02.021] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 02/26/2019] [Accepted: 02/27/2019] [Indexed: 12/20/2022]
Abstract
Lead is a neurotoxin that produces long-term, perhaps irreversible, effects on health and well-being. This article summarizes clinical and preclinical studies that have employed a variety of research techniques to examine the neurotoxic effects of low levels of lead exposure. A historical perspective is presented, followed by an overview of studies that examined behavioral and cognitive outcomes. In addition, a short summary of potential mechanisms of action is provided with a focus on calcium-dependent processes. The current level of concern, or reference level, set by the CDC is 5 μg/dL of lead in blood and a revision to 3.5 μg/dL has been suggested. However, levels of lead below 3 μg/dL have been shown to produce diminished cognitive function and maladaptive behavior in humans and animal models. Because much of the research has focused on higher concentrations of lead, work on low concentrations is needed to better understand the neurobehavioral effects and mechanisms of action of this neurotoxic metal.
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MESH Headings
- Adolescent
- Adolescent Behavior/drug effects
- Adolescent Development/drug effects
- Adult
- Age Factors
- Aged
- Animals
- Brain/drug effects
- Brain/growth & development
- Child
- Child Behavior/drug effects
- Child Development/drug effects
- Child, Preschool
- Cognition/drug effects
- Dose-Response Relationship, Drug
- History, 20th Century
- History, 21st Century
- Humans
- Lead Poisoning, Nervous System, Adult/history
- Lead Poisoning, Nervous System, Adult/physiopathology
- Lead Poisoning, Nervous System, Adult/psychology
- Lead Poisoning, Nervous System, Childhood/history
- Lead Poisoning, Nervous System, Childhood/physiopathology
- Lead Poisoning, Nervous System, Childhood/psychology
- Mice
- Middle Aged
- Rats
- Risk Assessment
- Risk Factors
- Toxicity Tests
- Young Adult
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Affiliation(s)
- Angelica Rocha
- California State University San Marcos, San Marcos, CA 92069, USA.
| | - Keith A Trujillo
- California State University San Marcos, San Marcos, CA 92069, USA
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Abstract
Millions of Americans now entering midlife and old age were exposed to high levels of lead, a neurotoxin, as children. Evidence from animal-model and human observational studies suggest that childhood lead exposure may raise the risk of adult neurodegenerative disease, particularly dementia, through a variety of possible mechanisms including epigenetic modification, delayed cardiovascular and kidney disease, direct degenerative CNS injury from lead remobilized from bone, and lowered neural and cognitive reserve. Within the next ten years, the generation of children with the highest historical lead exposures, those born in the 1960s, 1970s, and 1980s, will begin to enter the age at which dementia symptoms tend to emerge. Many will also enter the age in which lead stored in the skeleton may be remobilized at greater rates, particularly for women entering menopause and men and women experiencing osteoporosis. Should childhood lead exposure prove pro-degenerative, the next twenty years will provide the last opportunities for possible early intervention to forestall greater degenerative disease burden across the aging lead-exposed population. More evidence is needed now to characterize the nature and magnitude of the degenerative risks facing adults exposed to lead as children and to identify interventions to limit long-term harm.
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Affiliation(s)
- Aaron Reuben
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
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Lee KEM, Diacovo TG, Calderon J, Byrne MW, Ing C. Outcomes Research in Vulnerable Pediatric Populations. J Neurosurg Anesthesiol 2019; 31:140-143. [PMID: 30767939 PMCID: PMC9109709 DOI: 10.1097/ana.0000000000000544] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The Pediatric Anesthesia and Neurodevelopment Assessment (PANDA) study team held its biennial symposium in April 2018 to discuss issues on anesthetic neurotoxicity in the developing brain. One of the sessions invited speakers with different areas of expertise to discuss "Outcomes Research in Vulnerable Pediatric Populations." The vulnerable populations included neonates, children with congenital heart disease, children from low socioeconomic status, and children with incarcerated parents. Each speaker presented some of the ongoing research efforts in these groups as well as the challenges encountered in studying them.
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Affiliation(s)
- Ka-Eun M Lee
- Department of Anesthesiology, Columbia University Medical Center, Columbia University College of Physicians and Surgeons
| | - Thomas G Diacovo
- Departments of Pediatrics and Pharmacology, University of Pittsburgh Medical Center, Children's Hospital of Pittsburgh, Pittsburgh, PA
| | - Johanna Calderon
- Department of Psychiatry, Harvard Medical School, Boston Children's Hospital, Boston, MA
| | - Mary W Byrne
- Columbia University School of Nursing, Columbia University College of Physicians and Surgeons
| | - Caleb Ing
- Department of Anesthesiology and Epidemiology, Columbia University College of Physicians and Surgeons and Mailman School of Public Health, New York, NY
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Desrochers-Couture M, Oulhote Y, Arbuckle TE, Fraser WD, Séguin JR, Ouellet E, Forget-Dubois N, Ayotte P, Boivin M, Lanphear BP, Muckle G. Prenatal, concurrent, and sex-specific associations between blood lead concentrations and IQ in preschool Canadian children. ENVIRONMENT INTERNATIONAL 2018; 121:1235-1242. [PMID: 30392942 DOI: 10.1016/j.envint.2018.10.043] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 10/19/2018] [Accepted: 10/21/2018] [Indexed: 05/28/2023]
Abstract
BACKGROUND Lead exposure predicts altered neurodevelopment and lower intelligence quotient (IQ) in children, but few studies have examined this association in children who have relatively low blood lead concentrations. OBJECTIVES To test the associations between blood lead concentrations and cognitive function in Canadian preschoolers, with a possible moderation by sex. METHODS The data were gathered from 609 mother-child pairs from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study. Lead was measured in umbilical and maternal blood, and in children's venous blood at age 3-4 years. Cognitive function was measured with the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-III) at 3-4 years. We tested the relationship between WPPSI-III scores and blood lead concentrations with multiple linear regression, adding child sex as a moderator. RESULTS Median blood lead concentrations for the mother at 1st trimester and 3rd trimester of pregnancy, and for cord and child blood were 0.60 μg/dL, 0.58 μg/dL, 0.79 μg/dL and 0.67 μg/dL, respectively. We found no association between cord blood lead concentrations and WPPSI-III scores in multivariable analyses. However, cord blood lead concentrations showed a negative association with Performance IQ in boys but not in girls (B = 3.44; SE = 1.62; 95% CI: 0.82, 5.98). No associations were found between WPPSI-III scores and prenatal maternal blood or concurrent child blood lead concentrations. CONCLUSIONS Prenatal blood lead concentrations below 5 μg/dL were still associated with a decline in cognitive function in this Canadian cohort, but only for boys.
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Affiliation(s)
- Mireille Desrochers-Couture
- Centre de recherche du Centre Hospitalier Universitaire de Québec, Québec, Canada; École de psychologie, Université Laval, Quebec, Québec, Canada.
| | - Youssef Oulhote
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA, USA.
| | - Tye E Arbuckle
- Population Studies Division, Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada.
| | - William D Fraser
- Department of Obstetrics and Gynecology, Université de Sherbrooke, Centre Hospitalier Universitaire de Sherbrooke, Québec, Canada.
| | - Jean R Séguin
- CHU Sainte-Justine Research Center, Mother and Child University Hospital Center, Montreal, Québec, Canada; Department of Psychiatry, University of Montreal, Montreal, QC, Canada.
| | - Emmanuel Ouellet
- Centre de recherche du Centre Hospitalier Universitaire de Québec, Québec, Canada.
| | - Nadine Forget-Dubois
- Centre de recherche du Centre Hospitalier Universitaire de Québec, Québec, Canada; École de psychologie, Université Laval, Quebec, Québec, Canada.
| | - Pierre Ayotte
- Centre de toxicologie du Québec, Institut national de santé publique du Québec, Québec City, Québec, Canada.
| | - Michel Boivin
- École de psychologie, Université Laval, Quebec, Québec, Canada.
| | - Bruce P Lanphear
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada.
| | - Gina Muckle
- Centre de recherche du Centre Hospitalier Universitaire de Québec, Québec, Canada; École de psychologie, Université Laval, Quebec, Québec, Canada.
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14
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Calabrese EJ, Iavicoli I, Calabrese V, Cory-Slechta DA, Giordano J. Elemental mercury neurotoxicity and clinical recovery of function: A review of findings, and implications for occupational health. ENVIRONMENTAL RESEARCH 2018; 163:134-148. [PMID: 29438899 DOI: 10.1016/j.envres.2018.01.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/16/2018] [Accepted: 01/17/2018] [Indexed: 06/08/2023]
Abstract
This paper assessed approximately 30 studies, mostly involving occupationally exposed subjects, concerning the extent to which those who developed elemental mercury (Hg)-induced central and/or peripheral neurotoxicities from chronic or acute exposures recover functionality and/or performance. While some recovery occurred in the vast majority of cases, the extent of such recoveries varied considerably by individual and endpoint. Factors accounting for the extensive inter-individual variation in toxicity and recovery were not specifically assessed such as age, gender, diet, environmental enrichment, chelation strategies and dose-rate. While the data indicate that psychomotor endpoints often show substantial and relatively rapid (i.e., 2-6 months) recovery and that neuropsychological endpoints display slower and less complete recovery, generalizations are difficult due to highly variable study designs, use of different endpoints measured between studies, different Hg exposures based on blood/urine concentrations and Hg dose-rates, the poor capacity for replicating findings due to the unpredictable/episodic nature of harmful exposures to elemental Hg, and the inconsistency of the initiation of studies after induced toxicities and the differing periods of follow up during recovery periods. Finally, there is strikingly limited animal model literature on the topic of recovery/reversibility of elemental Hg toxicity, a factor which significantly contributes to the overall marked uncertainties for predicting the rate and magnitude of recovery and the factors that affect it.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, University of Massachusetts, Morrill I, N344, Amherst, MA 01003, USA.
| | - Ivo Iavicoli
- Department of Public Health, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy.
| | - Vittorio Calabrese
- Department of Biomed & Biotech Sciences, School of Medicine, University of Catania, Via Santa Sofia 97, Catania 95125, Italy.
| | - Deborah A Cory-Slechta
- Environmental Medicine, Pediatrics & Public Health Sciences, University of Rochester School of Medicine, Rochester, NY 14642, USA.
| | - James Giordano
- Department of Neurology and Biochemistry, and Neuroethics Studies Program-Pellegrino Center for Clinical Bioethics, Georgetown University Medical Center, Washington, D.C. 20057, USA.
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Zhao ZH, Zheng G, Wang T, Du KJ, Han X, Luo WJ, Shen XF, Chen JY. Low-level Gestational Lead Exposure Alters Dendritic Spine Plasticity in the Hippocampus and Reduces Learning and Memory in Rats. Sci Rep 2018; 8:3533. [PMID: 29476096 PMCID: PMC5824819 DOI: 10.1038/s41598-018-21521-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 02/05/2018] [Indexed: 11/24/2022] Open
Abstract
Lead (Pb) is known to impair children's cognitive function. It has been previously shown that developmental Pb exposure alters dendritic spine formation in hippocampal pyramidal neurons. However, the underlying mechanism has not yet been defined. In this study, a low-level gestational Pb exposure (GLE) rat model was employed to investigate the impact of Pb on the spine density of the hippocampal pyramidal neurons and its regulatory mechanism. Pb exposure resulted in impaired performance of the rats in the Morris water maze tasks, and in decreased EPSC amplitudes in hippocampal CA3-CA1 regions. With a 3D reconstruction by the Imaris software, the results from Golgi staining showed that the spine density in the CA1 region was reduced in the Pb-exposed rats in a dose-dependent manner. Decreased spine density was also observed in cultured hippocampal neurons following the Pb treatment. Furthermore, the expression level of NLGN1, a postsynaptic protein that mediates synaptogenesis, was significantly decreased following the Pb exposure both in vivo and in vitro. Up-regulation of NLGN1 in cultured primary neurons partially attenuated the impact of Pb on the spine density. Taken together, our resultssuggest that Pb exposure alters spine plasticity in the developing hippocampus by down-regulating NLGN1 protein levels.
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Affiliation(s)
- Zai-Hua Zhao
- Department of Occupational and Environmental Health and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, No 169 of West Changle Road, Xi'an, Shaanxi, 710032, China
| | - Gang Zheng
- Department of Occupational and Environmental Health and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, No 169 of West Changle Road, Xi'an, Shaanxi, 710032, China
| | - Tao Wang
- Department of Occupational and Environmental Health and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, No 169 of West Changle Road, Xi'an, Shaanxi, 710032, China
| | - Ke-Jun Du
- Department of Occupational and Environmental Health and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, No 169 of West Changle Road, Xi'an, Shaanxi, 710032, China
| | - Xiao Han
- Department of Occupational and Environmental Health and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, No 169 of West Changle Road, Xi'an, Shaanxi, 710032, China
| | - Wen-Jing Luo
- Department of Occupational and Environmental Health and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, No 169 of West Changle Road, Xi'an, Shaanxi, 710032, China
| | - Xue-Feng Shen
- Department of Occupational and Environmental Health and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, No 169 of West Changle Road, Xi'an, Shaanxi, 710032, China.
| | - Jing-Yuan Chen
- Department of Occupational and Environmental Health and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, No 169 of West Changle Road, Xi'an, Shaanxi, 710032, China.
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16
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Lewis BA, Minnes S, Min MO, Short EJ, Wu M, Lang A, Weishampel P, Singer LT. Blood lead levels and longitudinal language outcomes in children from 4 to 12 years. JOURNAL OF COMMUNICATION DISORDERS 2018; 71:85-96. [PMID: 29373108 PMCID: PMC5801000 DOI: 10.1016/j.jcomdis.2018.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 12/27/2017] [Accepted: 01/09/2018] [Indexed: 06/07/2023]
Abstract
OBJECTIVES In this study, the authors aimed to examine the association of a range of blood lead levels on language skills assessed at 4, 6, 10 and 12 years of age using a prospective longitudinal design controlling for potential confounding variables including maternal vocabulary, caregiver's psychological distress and symptomatology, child's race and prenatal drug exposure. METHODS The participants (N = 278) were a subsample of a large longitudinal study that examined the association of prenatal drug exposure on children who were followed prospectively from birth and assessed for receptive and expressive language skills at 4, 6, 10 and 12 years of age. Blood lead levels were determined at 4-years of age by atomic absorption spectrometry. A mixed model approach with restricted maximum likelihood procedures was used to assess the association of lead on language outcomes. RESULTS Longitudinal mixed model analyses suggested a negative effect of lead exposure on both receptive and expressive language, with the adverse outcomes of lead exposure appearing to become more prominent at 10 and 12 years. Higher caregiver vocabulary was positively associated with child's language scores whereas caregiver psychological distress appeared to negatively affect language scores. Prenatal drug exposure was not related to the effects of lead on language skills. CONCLUSIONS These findings suggest that elevated blood lead levels occurring early in life may be associated with poorer language skills at older ages. A language rich environment may minimize the negative influence of early lead exposure on language skills, with psychological distress seemingly exacerbating the negative outcome.
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Affiliation(s)
- Barbara A Lewis
- Department of Psychological Sciences, Case Western Reserve University, United States.
| | - Sonia Minnes
- Mandel School of Applied Social Sciences, Case Western Reserve University, United States
| | - Meeyoung O Min
- Mandel School of Applied Social Sciences, Case Western Reserve University, United States
| | - Elizabeth J Short
- Department of Psychological Sciences, Case Western Reserve University, United States
| | - Miaoping Wu
- Mandel School of Applied Social Sciences, Case Western Reserve University, United States
| | - Adelaide Lang
- Mandel School of Applied Social Sciences, Case Western Reserve University, United States
| | - Paul Weishampel
- Mandel School of Applied Social Sciences, Case Western Reserve University, United States
| | - Lynn T Singer
- Departments of Pediatrics and Environmental Health Sciences, Case Western Reserve University, United States
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17
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Jungling A, Reglodi D, Karadi ZN, Horvath G, Farkas J, Gaszner B, Tamas A. Effects of Postnatal Enriched Environment in a Model of Parkinson's Disease in Adult Rats. Int J Mol Sci 2017; 18:E406. [PMID: 28216584 PMCID: PMC5343940 DOI: 10.3390/ijms18020406] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/01/2017] [Accepted: 02/06/2017] [Indexed: 01/01/2023] Open
Abstract
Environmental enrichment is a widespread neuroprotective strategy during development and also in the mature nervous system. Several research groups have described that enriched environment in adult rats has an impact on the progression of Parkinson's disease (PD). The aim of our present study was to examine the effects of early, postnatal environmental enrichment after 6-hydroxydopamine-induced (6-OHDA) lesion of the substantia nigra in adulthood. Newborn Wistar rats were divided into control and enriched groups according to their environmental conditions. For environmental enrichment, during the first five postnatal weeks animals were placed in larger cages and exposed to intensive complex stimuli. Dopaminergic cell loss, and hypokinetic and asymmetrical signs were evaluated after inducing PD with unilateral injections of 6-OHDA in three-month-old animals. Treatment with 6-OHDA led to a significant cell loss in the substantia nigra of control animals, however, postnatal enriched circumstances could rescue the dopaminergic cells. Although there was no significant difference in the percentage of surviving cells between 6-OHDA-treated control and enriched groups, the slightly less dopaminergic cell loss in the enriched group compared to control animals resulted in less severe hypokinesia. Our investigation is the first to provide evidence for the neuroprotective effect of postnatal enriched environment in PD later in life.
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Affiliation(s)
- Adel Jungling
- Department of Anatomy, University of Pecs Medical School, Pecs 7624, Hungary.
| | - Dora Reglodi
- Department of Anatomy, University of Pecs Medical School, Pecs 7624, Hungary.
| | | | - Gabor Horvath
- Department of Anatomy, University of Pecs Medical School, Pecs 7624, Hungary.
| | - Jozsef Farkas
- Department of Anatomy, University of Pecs Medical School, Pecs 7624, Hungary.
| | - Balazs Gaszner
- Department of Anatomy, University of Pecs Medical School, Pecs 7624, Hungary.
| | - Andrea Tamas
- Department of Anatomy, University of Pecs Medical School, Pecs 7624, Hungary.
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18
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Hubbs-Tait L, Nation JR, Krebs NF, Bellinger DC. Neurotoxicants, Micronutrients, and Social Environments. Psychol Sci Public Interest 2016; 6:57-121. [DOI: 10.1111/j.1529-1006.2005.00024.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
SUMMARY—Systematic research evaluating the separate and interacting impacts of neurotoxicants, micronutrients, and social environments on children's cognition and behavior has only recently been initiated. Years of extensive human epidemiologic and animal experimental research document the deleterious impact of lead and other metals on the nervous system. However, discrepancies among human studies and between animal and human studies underscore the importance of variations in child nutrition as well as social and behavioral aspects of children's environments that mitigate or exacerbate the effects of neurotoxicants. In this monograph, we review existing research on the impact of neurotoxic metals, nutrients, and social environments and interactions across the three domains. We examine the literature on lead, mercury, manganese, and cadmium in terms of dispersal, epidemiology, experimental animal studies, effects of social environments, and effects of nutrition. Research documenting the negative impact of lead on cognition and behavior influenced reductions by the Center for Disease Control in child lead-screening guidelines from 30 micrograms per deciliter (μg/dL) in 1975 to 25 μg/dL in 1985 and to 10 μg/dL in 1991. A further reduction is currently being considered. Experimental animal research documents lead's alteration of glutamate-neurotransmitter (particularly N-methyl-D-aspartate) activity vital to learning and memory. In addition, lead induces changes in cholinergic and dopaminergic activity. Elevated lead concentrations in the blood are more common among children living in poverty and there is some evidence that socioeconomic status influences associations between lead and child outcomes. Micronutrients that influence the effects of lead include iron and zinc. Research documenting the negative impact of mercury on children (as well as adults) has resulted in a reference dose (RfD) of 0.1 microgram per kilogram of body weight per day (μg/kg/day). In animal studies, mercury interferes with glutamatergic, cholinergic, and dopaminergic activity. Although evidence for interactions of mercury with children's social contexts is minimal, researchers are examining interactions of mercury with several nutrients. Research on the effects of cadmium and manganese on child cognition and behavior is just beginning. Experimental animal research links cadmium to learning deficits, manganese to behaviors characteristic of Parkinson's disease, and both to altered dopaminergic functioning. We close our review with a discussion of policy implications, and we recommend interdisciplinary research that will enable us to bridge gaps within and across domains.
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Affiliation(s)
- Laura Hubbs-Tait
- Department of Human Development and Family Science, Oklahoma State University
| | | | - Nancy F. Krebs
- Department of Pediatrics, University of Colorado School of Medicine
| | - David C. Bellinger
- Department of Neurology, Harvard Medical School; Department of Environmental Health, Harvard School of Public Health; and Children's Hospital Boston
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19
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Bertozzi B, Tosti V, Fontana L. Beyond Calories: An Integrated Approach to Promote Health, Longevity, and Well-Being. Gerontology 2016; 63:13-19. [PMID: 27173125 DOI: 10.1159/000446346] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 04/21/2016] [Indexed: 11/19/2022] Open
Abstract
In 1948, the World Health Organization defined health as 'a state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity'. Detractors claim that this definition of health is utopian and unrealistic. However, accumulating evidence from experimental studies suggests that aging is not inevitably linked with the development of chronic diseases, and the age-associated accumulation of molecular damage can be prevented or greatly delayed by dietary and genetic manipulations that downregulate key cellular nutrient-sensing pathways. Nonetheless, to obtain a state of complete physical, mental, and social well-being, we as human beings need to go beyond nutrition or pharmacological treatments and implement a combination of interventions that enhance not only our metabolic health but also our psychological, emotional, intellectual and spiritual development, our social relationships and cultural well-being. This perspective highlights a range of scientific research-based interventions that can potentially be used to promote human health and longevity. We will also briefly address the importance of environmental health in achieving this goal.
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Affiliation(s)
- Beatrice Bertozzi
- Division of Geriatrics and Nutritional Science, Washington University, St. Louis, Mo., USA
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20
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Brunst KJ, Baccarelli AA, Wright RJ. Integrating mitochondriomics in children's environmental health. J Appl Toxicol 2015; 35:976-91. [PMID: 26046650 PMCID: PMC4714560 DOI: 10.1002/jat.3182] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 04/23/2015] [Indexed: 12/18/2022]
Abstract
The amount of scientific research linking environmental exposures and childhood health outcomes continues to grow; yet few studies have teased out the mechanisms involved in environmentally-induced diseases. Cells can respond to environmental stressors in many ways: inducing oxidative stress/inflammation, changes in energy production and epigenetic alterations. Mitochondria, tiny organelles that each retains their own DNA, are exquisitely sensitive to environmental insults and are thought to be central players in these pathways. While it is intuitive that mitochondria play an important role in disease processes, given that every cell of our body is dependent on energy metabolism, it is less clear how environmental exposures impact mitochondrial mechanisms that may lead to enhanced risk of disease. Many of the effects of the environment are initiated in utero and integrating mitochondriomics into children's environmental health studies is a critical priority. This review will highlight (i) the importance of exploring environmental mitochondriomics in children's environmental health, (ii) why environmental mitochondriomics is well suited to biomarker development in this context, and (iii) how molecular and epigenetic changes in mitochondria and mitochondrial DNA (mtDNA) may reflect exposures linked to childhood health outcomes.
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Affiliation(s)
- Kelly J. Brunst
- Kravis Children’s Hospital, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Andrea A. Baccarelli
- Department of Environmental Health, Laboratory of Environmental Epigenetics, Exposure Epidemiology and Risk Program, Harvard T. H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA
| | - Rosalind J. Wright
- Kravis Children’s Hospital, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, 1428 Madison Avenue, New York, NY 10029, USA
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21
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Liu F, Xue Z, Li N, Huang H, Ying Y, Li J, Wang L, Li W. Effects of lead exposure on the expression of amyloid β and phosphorylated tau proteins in the C57BL/6 mouse hippocampus at different life stages. J Trace Elem Med Biol 2014; 28:227-232. [PMID: 24582137 DOI: 10.1016/j.jtemb.2014.01.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 01/10/2014] [Accepted: 01/17/2014] [Indexed: 01/26/2023]
Abstract
The objective of this study was to investigate the effects of lead exposure on spatial learning and memory capacity and the expression of amyloid β and phosphorylated tau proteins in the mouse hippocampus. A total of 24 adult C57BL/6 mice (12 of each sex) were mated at a 1:1 ratio. After delivery, the litters were normalised to 6 pups per litter. During the lactation period, the pups were randomly separated into four groups: control, early exposure, late exposure, or long-term exposure. These groups were not exposed to lead, exposed to lead from birth to week 24, exposed to lead from week 24 to week 48, or exposed to lead from birth to 48 weeks of age, respectively. Lead exposure was induced by providing Pb-contaminated drinking water at a concentration of 0.1%. All of the pups were fed until 72 weeks of age, at which time their spatial learning and memory capacity was evaluated via the Morris water maze test. Then, the lead levels in their blood and hippocampus were measured via graphite furnace atomic absorption spectrometry. The protein expression of amyloid β and phosphorylated tau in the hippocampus was detected via Western blot. The results revealed that the hippocampal and blood lead levels were significantly higher in all of the groups exposed to lead than the control group (P<0.05). The spatial learning and memory performances of the lead-exposed groups were much poorer than those of the control group (P<0.05). The expression levels of amyloid β and phosphorylated tau proteins were increased in the lead-exposed groups compared to the control group (P<0.05). The enhanced expressions of amyloid β and phosphorylated tau proteins might contribute to the impairment in spatial learning and memory in the lead-exposed mice.
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Affiliation(s)
- Fangli Liu
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China; Institute of Public Health, Henan University, Kaifeng 475004, China
| | - Zhenfei Xue
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China
| | - Ning Li
- Food Science Technology College of Henan Agricultural University, Zhengzhou 450002, China
| | - Hui Huang
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China
| | - Yanyan Ying
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China
| | - Jin Li
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China
| | - Lin Wang
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China
| | - Wenjie Li
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China.
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Mychasiuk R, Muhammad A, Kolb B. Environmental enrichment alters structural plasticity of the adolescent brain but does not remediate the effects of prenatal nicotine exposure. Synapse 2014; 68:293-305. [PMID: 24616009 DOI: 10.1002/syn.21737] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 01/15/2014] [Indexed: 12/20/2022]
Abstract
Exposure to both drugs of abuse and environmental enrichment (EE) are widely studied experiences that induce large changes in dendritic morphology and synaptic connectivity. As there is an abundance of literature using EE as a treatment strategy for drug addiction, we sought to determine whether EE could remediate the effects of prenatal nicotine (PN) exposure. Using Golgi-Cox staining, we examined eighteen neuroanatomical parameters in four brain regions [medial prefrontal cortex (mPFC), orbital frontal cortex (OFC), nucleus accumben, and Par1] of Long-Evans rats. EE in adolescence dramatically altered structural plasticity in the male and female brain, modifying 60% of parameters investigated. EE normalized three parameters (OFC spine density and dendritic branching and mPFC dendritic branching) in male offspring exposed to nicotine prenatally but did not remediate any measures in female offspring. PN exposure interfered with adolescent EE-induced changes in five neuroanatomical measurements (Par1 spine density and dendritic branching in both male and female offspring, and mPFC spine density in male offspring). And in four neuroanatomical parameters examined, PN exposure and EE combined to produce additive effects [OFC spine density in females and mPFC dendritic length (apical and basilar) and branching in males]. Despite demonstrated efficacy in reversing drug addiction, EE was not able to reverse many of the PN-induced changes in neuronal morphology, indicating that modifications in neural circuitry generated in the prenatal period may be more resistant to change than those generated in the adult brain.
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Affiliation(s)
- Richelle Mychasiuk
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
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23
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Sutton P, Woodruff TJ. Risk communication and decision tools for children's health protection. ACTA ACUST UNITED AC 2014; 99:45-9. [PMID: 23723171 DOI: 10.1002/bdrc.21029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 03/06/2013] [Indexed: 11/11/2022]
Abstract
Scientific discovery linking the environment to beneficial and adverse health children's health outcomes is rapidly expanding, leading scientists and health professionals to call for timely action to prevent harm and secure benefits. A robust method to synthesize what is known about the environmental drivers of health is a foundational step to making the science actionable by individuals and decision-makers. To meet this need, a methodology called the Navigation Guide was crafted by a collaboration of 22 clinical and environmental health scientists. The Navigation Guide proceeds from methods of research synthesis used in clinical settings but accounts for differences between environmental and clinical health sciences related to the evidence-base and decision-context. The methodology can be used to develop evidence profiles that provide simple, transparent summaries, such as practice guidelines or other evidence-based recommendations for prevention. Establishing proof-of-concept of the method is underway. Development of the Navigation Guide is extremely timely as it coincides with growing recognition of the need for updated methods in risk assessment. The costs in 2008 to the US healthcare system for treatment of childhood illnesses linked to toxic environmental exposures is conservatively estimated to be over $76 billion, and it is anticipated that US healthcare policy decisions will increasingly rely on systematic reviews of the evidence. The Navigation Guide is poised to provide a methodological bridge to link healthcare decision-making to efforts to reduce toxic environmental exposures. The institutionalization of the Navigation Guide would provide a concrete mechanism for linking science to action to protect children's health.
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Affiliation(s)
- Patrice Sutton
- Department of Obstetrics, Gynecology and Reproductive Sciences, Program on Reproductive Health and the Environment, University of California, San Francisco, Oakland, California 94162, USA.
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Geng F, Mai X, Zhan J, Xu L, Shao J, Meeker J, Lozoff B. Low-level prenatal lead exposure alters auditory recognition memory in 2-month-old infants: an event-related potentials (ERPs) study. Dev Neuropsychol 2014; 39:516-28. [PMID: 25350757 PMCID: PMC4212318 DOI: 10.1080/87565641.2014.959172] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
This study used event-related potentials (ERPs) to assess effects of low-level prenatal lead exposure on auditory recognition memory in 2-month-old infants. Infants were divided into four groups according to cord-blood lead concentration: (1) <2.00 μ g/dL, (2) 2.00-2.99 μ g/dL, (3) 3.0-3.7 μ g/dL, and (4) ≥3.7 μ g/dL. The first group showed the normally expected differences in P2, P750, and late slow wave (LSW) amplitudes elicited by mothers' and strangers' voices. These differences were not observed for one or more ERP components in the other groups. Thus, there was electrophysiological evidence of poorer auditory recognition memory at 2 months with cord-blood lead ≥2.00 μ g/dL.
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Affiliation(s)
- Fengji Geng
- Center for Human Growth and Development, University of Michigan, Ann Arbor, Michigan
| | - Xiaoqin Mai
- Department of Psychology, Renmin University, Beijing, China
| | - Jianying Zhan
- Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lin Xu
- Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jie Shao
- Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - John Meeker
- School of Public Research, University of Michigan, Ann Arbor, Michigan
| | - Betsy Lozoff
- Center for Human Growth and Development, University of Michigan, Ann Arbor, Michigan
- Department of Pediatrics and Communicable Diseases, University of Michigan
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Environmental enrichment decreases asphyxia-induced neurobehavioral developmental delay in neonatal rats. Int J Mol Sci 2013; 14:22258-73. [PMID: 24232451 PMCID: PMC3856064 DOI: 10.3390/ijms141122258] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Revised: 10/18/2013] [Accepted: 10/28/2013] [Indexed: 01/01/2023] Open
Abstract
Perinatal asphyxia during delivery produces long-term disability and represents a major problem in neonatal and pediatric care. Numerous neuroprotective approaches have been described to decrease the effects of perinatal asphyxia. Enriched environment is a popular strategy to counteract nervous system injuries. The aim of the present study was to investigate whether enriched environment is able to decrease the asphyxia-induced neurobehavioral developmental delay in neonatal rats. Asphyxia was induced in ready-to-deliver mothers by removing the pups by caesarian section after 15 min of asphyxia. Somatic and neurobehavioral development was tested daily and motor coordination weekly. Our results show that rats undergoing perinatal asphyxia had a marked developmental delay and worse performance in motor coordination tests. However, pups kept in enriched environment showed a decrease in the developmental delay observed in control asphyctic pups. Rats growing up in enriched environment did not show decrease in weight gain after the first week and the delay in reflex appearance was not as marked as in control rats. In addition, the development of motor coordination was not as strikingly delayed as in the control group. Short-term neurofunctional outcome are known to correlate with long-term deficits. Our results thus show that enriched environment could be a powerful strategy to decrease the deleterious developmental effects of perinatal asphyxia.
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Horvath G, Reglodi D, Vadasz G, Farkas J, Kiss P. Exposure to enriched environment decreases neurobehavioral deficits induced by neonatal glutamate toxicity. Int J Mol Sci 2013; 14:19054-66. [PMID: 24065102 PMCID: PMC3794820 DOI: 10.3390/ijms140919054] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 08/08/2013] [Accepted: 08/14/2013] [Indexed: 12/30/2022] Open
Abstract
Environmental enrichment is a popular strategy to enhance motor and cognitive performance and to counteract the effects of various harmful stimuli. The protective effects of enriched environment have been shown in traumatic, ischemic and toxic nervous system lesions. Monosodium glutamate (MSG) is a commonly used taste enhancer causing excitotoxic effects when given in newborn animals. We have previously demonstrated that MSG leads to a delay in neurobehavioral development, as shown by the delayed appearance of neurological reflexes and maturation of motor coordination. In the present study we aimed at investigating whether environmental enrichment is able to decrease the neurobehavioral delay caused by neonatal MSG treatment. Newborn pups were treated with MSG subcutaneously on postnatal days 1, 5 and 9. For environmental enrichment, we placed rats in larger cages, supplemented with different toys that were altered daily. Normal control and enriched control rats received saline treatment only. Physical parameters such as weight, day of eye opening, incisor eruption and ear unfolding were recorded. Animals were observed for appearance of reflexes such as negative geotaxis, righting reflexes, fore- and hindlimb grasp, fore- and hindlimb placing, sensory reflexes and gait. In cases of negative geotaxis, surface righting and gait, the time to perform the reflex was also recorded daily. For examining motor coordination, we performed grid walking, footfault, rope suspension, rota-rod, inclined board and walk initiation tests. We found that enriched environment alone did not lead to marked alterations in the course of development. On the other hand, MSG treatment caused a slight delay in reflex development and a pronounced delay in weight gain and motor coordination maturation. This delay in most signs and tests could be reversed by enriched environment: MSG-treated pups kept under enriched conditions showed no weight retardation, no reflex delay in some signs and performed better in most coordination tests. These results show that environmental enrichment is able to decrease the neurobehavioral delay caused by neonatal excitotoxicity.
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Affiliation(s)
- Gabor Horvath
- Department of Anatomy, PTE-MTA Lendulet PACAP Research Team, University of Pecs, Pécs 7624, Hungary.
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Gender-dependent effects of enriched environment and social isolation in ischemic retinal lesion in adult rats. Int J Mol Sci 2013; 14:16111-23. [PMID: 23921682 PMCID: PMC3759902 DOI: 10.3390/ijms140816111] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 07/10/2013] [Accepted: 07/17/2013] [Indexed: 12/17/2022] Open
Abstract
Exposure to an enriched environment has been shown to have many positive effects on brain structure and function. Numerous studies have proven that enriched environment can reduce the lesion induced by toxic and traumatic injuries. Impoverished environment, on the other hand, can have deleterious effects on the outcome of neuronal injuries. We have previously shown that enriched conditions have protective effects in retinal injury in newborn rats. It is well-known that the efficacy of neuroprotective strategies can depend on age and gender. The aim of the present study, therefore, was to examine the effects of environmental enrichment and social isolation in retinal ischemia. We used bilateral common carotid artery occlusion to induce retinal hypoperfusion in adult Wistar rats of both genders. Groups were housed in standard, enriched or impoverished conditions. Impoverished environment was induced by social isolation. Retinas were processed for histological analysis after two weeks of survival. In the present study, we show that (1) enriched environment has protective effects in adult ischemic retinal lesion, while (2) impoverished environment further increases the degree of ischemic injury, and (3) that these environmental effects are gender-dependent: females are less responsive to the positive effects of environmental enrichment and more vulnerable to retinal ischemia in social isolation. In summary, our present study shows that the effects of both positive and negative environmental stimuli are gender-dependent in ischemic retinal lesions.
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Chiu YHM, Bellinger DC, Coull BA, Anderson S, Barber R, Wright RO, Wright RJ. Associations between traffic-related black carbon exposure and attention in a prospective birth cohort of urban children. ENVIRONMENTAL HEALTH PERSPECTIVES 2013; 121:859-64. [PMID: 23665743 PMCID: PMC3701996 DOI: 10.1289/ehp.1205940] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 05/01/2013] [Indexed: 05/17/2023]
Abstract
BACKGROUND Ambient air pollution may have neurotoxic effects in children. Data examining associations between traffic-related air pollution and attention domains remain sparse. OBJECTIVES We examined associations between black carbon (BC), a marker of traffic particles, and attention measures ascertained at 7-14 years of age among 174 children in a birth cohort based in the Boston, Massachusetts, area. METHODS We estimated BC levels using a validated spatial-temporal land-use regression model based on residence during children's lifetime. Children completed the Conner's Continuous Performance Test (CPT) measuring omission errors, commission errors, and hit reaction time (HRT), with higher scores indicating increased errors or slower reaction time. Multivariable-adjusted linear regression analyses were used to examine associations between BC and each attention outcome. RESULTS Children were primarily Hispanic (56%) and Caucasian (41%); 53% were boys. We found a positive association between higher BC levels with increased commission errors and slower HRT, adjusting for child IQ, age, sex, blood lead level, maternal education, pre- and postnatal tobacco smoke exposure, and community-level social stress. Notably, the association was weaker, though still positive, for the highest BC quartile relative to the middle two quartiles. Sex-stratified analysis demonstrated statistically significant associations between BC and both commission errors and HRT in boys, but BC was not significantly associated with any of the CPT outcomes in girls. CONCLUSIONS In this population of urban children, we found associations between BC exposure and higher commission errors and slower reaction time. These associations were overall more apparent in boys than girls.
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Cory-Slechta DA, Weston D, Liu S, Allen JL. Brain hemispheric differences in the neurochemical effects of lead, prenatal stress, and the combination and their amelioration by behavioral experience. Toxicol Sci 2013; 132:419-30. [PMID: 23358193 DOI: 10.1093/toxsci/kft015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Brain lateralization, critical to mediation of cognitive functions and to "multitasking," is disrupted in conditions such as attention deficit disorder and schizophrenia. Both low-level lead (Pb) exposure and prenatal stress (PS) have been associated with mesocorticolimbic system-mediated executive-function cognitive and attention deficits. Mesocorticolimbic systems demonstrate significant laterality. Thus, altered brain lateralization could play a role in this behavioral toxicity. This study examined laterality of mesocorticolimbic monoamines (frontal cortex, nucleus accumbens, striatum, midbrain) and amino acids (frontal cortex) in male and female rats subjected to lifetime Pb exposure (0 or 50 ppm in drinking water), PS (restraint stress on gestational days 16-17), or the combination with and without repeated learning behavioral experience. Control males exhibited prominent laterality, particularly in midbrain and also in frontal cortex and striatum; females exhibited less laterality, and this was primarily striatal. Lateralized Pb ± PS induced neurotransmitter changes were assessed only in males because of limited sample sizes of Pb + PS females. In males, Pb ± PS changes occurred in left hemisphere of frontal cortex and right hemisphere of midbrain. Behavioral experience modified the laterality of Pb ± PS-induced neurotransmitter changes in a region-dependent manner. Notably, behavioral experience eliminated Pb ± PS neurotransmitter changes in males. These findings underscore the critical need to evaluate both sexes and brain hemispheres for the mechanistic understanding of sex-dependent differences in neuro- and behavioral toxicity. Furthermore, assessment of central nervous system mechanisms in the absence of behavioral experience, shown here for males, may constitute less relevant models of human health effects.
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Affiliation(s)
- Deborah A Cory-Slechta
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, New York 14642, USA.
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30
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Fares RP, Belmeguenai A, Sanchez PE, Kouchi HY, Bodennec J, Morales A, Georges B, Bonnet C, Bouvard S, Sloviter RS, Bezin L. Standardized environmental enrichment supports enhanced brain plasticity in healthy rats and prevents cognitive impairment in epileptic rats. PLoS One 2013; 8:e53888. [PMID: 23342033 PMCID: PMC3544705 DOI: 10.1371/journal.pone.0053888] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 12/04/2012] [Indexed: 12/23/2022] Open
Abstract
Environmental enrichment of laboratory animals influences brain plasticity, stimulates neurogenesis, increases neurotrophic factor expression, and protects against the effects of brain insult. However, these positive effects are not constantly observed, probably because standardized procedures of environmental enrichment are lacking. Therefore, we engineered an enriched cage (the Marlau™ cage), which offers: (1) minimally stressful social interactions; (2) increased voluntary exercise; (3) multiple entertaining activities; (4) cognitive stimulation (maze exploration), and (5) novelty (maze configuration changed three times a week). The maze, which separates food pellet and water bottle compartments, guarantees cognitive stimulation for all animals. Compared to rats raised in groups in conventional cages, rats housed in Marlau™ cages exhibited increased cortical thickness, hippocampal neurogenesis and hippocampal levels of transcripts encoding various genes involved in tissue plasticity and remodeling. In addition, rats housed in Marlau™ cages exhibited better performances in learning and memory, decreased anxiety-associated behaviors, and better recovery of basal plasma corticosterone level after acute restraint stress. Marlau™ cages also insure inter-experiment reproducibility in spatial learning and brain gene expression assays. Finally, housing rats in Marlau™ cages after severe status epilepticus at weaning prevents the cognitive impairment observed in rats subjected to the same insult and then housed in conventional cages. By providing a standardized enriched environment for rodents during housing, the Marlau™ cage should facilitate the uniformity of environmental enrichment across laboratories.
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MESH Headings
- Adaptation, Psychological/physiology
- Animals
- Anxiety/complications
- Body Weight
- Brain/cytology
- Brain/pathology
- Brain/physiology
- Brain/physiopathology
- CA1 Region, Hippocampal/cytology
- CA1 Region, Hippocampal/pathology
- CA1 Region, Hippocampal/physiology
- CA1 Region, Hippocampal/physiopathology
- Cognition
- Eating
- Exploratory Behavior/physiology
- Health
- Housing, Animal/standards
- Lipid Metabolism
- Male
- Neurogenesis/genetics
- Neuronal Plasticity
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Reference Standards
- Reproducibility of Results
- Restraint, Physical/psychology
- Status Epilepticus/pathology
- Status Epilepticus/physiopathology
- Status Epilepticus/psychology
- Stress, Psychological/complications
- Stress, Psychological/pathology
- Stress, Psychological/physiopathology
- Synapses/pathology
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Affiliation(s)
- Raafat P. Fares
- Université de Lyon, Lyon, France
- Université Lyon 1, Villeurbanne, France
- Inserm, Institut National de la Santé et de la Recherche Médicale, U1028, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- CNRS, Centre National de la Recherche Scientifique, UMR5292, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- IDÉE, Institut Des ÉpilepsiEs, Lyon, France
- IRBA, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France
| | - Amor Belmeguenai
- Université de Lyon, Lyon, France
- Université Lyon 1, Villeurbanne, France
- Inserm, Institut National de la Santé et de la Recherche Médicale, U1028, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- CNRS, Centre National de la Recherche Scientifique, UMR5292, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- IDÉE, Institut Des ÉpilepsiEs, Lyon, France
| | - Pascal E. Sanchez
- Université de Lyon, Lyon, France
- Université Lyon 1, Villeurbanne, France
- Inserm, Institut National de la Santé et de la Recherche Médicale, U1028, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- CNRS, Centre National de la Recherche Scientifique, UMR5292, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- IDÉE, Institut Des ÉpilepsiEs, Lyon, France
| | - Hayet Y. Kouchi
- Université de Lyon, Lyon, France
- Université Lyon 1, Villeurbanne, France
- Inserm, Institut National de la Santé et de la Recherche Médicale, U1028, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- CNRS, Centre National de la Recherche Scientifique, UMR5292, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- IDÉE, Institut Des ÉpilepsiEs, Lyon, France
| | - Jacques Bodennec
- Université de Lyon, Lyon, France
- Université Lyon 1, Villeurbanne, France
- Inserm, Institut National de la Santé et de la Recherche Médicale, U1028, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- CNRS, Centre National de la Recherche Scientifique, UMR5292, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- IDÉE, Institut Des ÉpilepsiEs, Lyon, France
| | - Anne Morales
- Université de Lyon, Lyon, France
- Université Lyon 1, Villeurbanne, France
- Inserm, Institut National de la Santé et de la Recherche Médicale, U1028, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- CNRS, Centre National de la Recherche Scientifique, UMR5292, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- IDÉE, Institut Des ÉpilepsiEs, Lyon, France
| | - Béatrice Georges
- Université de Lyon, Lyon, France
- Université Lyon 1, Villeurbanne, France
- Inserm, Institut National de la Santé et de la Recherche Médicale, U1028, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- CNRS, Centre National de la Recherche Scientifique, UMR5292, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- IDÉE, Institut Des ÉpilepsiEs, Lyon, France
| | - Chantal Bonnet
- Université de Lyon, Lyon, France
- Université Lyon 1, Villeurbanne, France
- Inserm, Institut National de la Santé et de la Recherche Médicale, U1028, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- CNRS, Centre National de la Recherche Scientifique, UMR5292, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- IDÉE, Institut Des ÉpilepsiEs, Lyon, France
| | - Sandrine Bouvard
- Université de Lyon, Lyon, France
- Université Lyon 1, Villeurbanne, France
- Inserm, Institut National de la Santé et de la Recherche Médicale, U1028, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- CNRS, Centre National de la Recherche Scientifique, UMR5292, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- IDÉE, Institut Des ÉpilepsiEs, Lyon, France
| | - Robert S. Sloviter
- Department of Neurobiology, Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, United States of America
| | - Laurent Bezin
- Université de Lyon, Lyon, France
- Université Lyon 1, Villeurbanne, France
- Inserm, Institut National de la Santé et de la Recherche Médicale, U1028, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- CNRS, Centre National de la Recherche Scientifique, UMR5292, Lyon Neuroscience Research Center, Tiger Team, Lyon, France
- IDÉE, Institut Des ÉpilepsiEs, Lyon, France
- * E-mail:
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Anderson DW, Mettil WA, Schneider JS. Rearing environment, sex and developmental lead exposure modify gene expression in the hippocampus of behaviorally naïve animals. Neurochem Int 2013; 62:510-20. [PMID: 23318674 DOI: 10.1016/j.neuint.2013.01.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 12/06/2012] [Accepted: 01/04/2013] [Indexed: 10/27/2022]
Abstract
Developmental lead (Pb) exposure impairs various cognitive processes and behaviors in both humans and animals. In particular, specific deficits in spatial learning and memory have been described in Pb-exposed rats. It is also known that rearing environment (i.e., non-enriched vs. enriched) can have significant influences on cognitive performance and that rearing environment and sex may modify the influence of Pb exposure on learning and memory processes. It is also known that behavioral testing can alter hippocampal gene expression and interactive effects of environment. Little is known however about the molecular correlates of developmental Pb-exposure on expression of key sets of cognition-relevant genes in the hippocampus and how sex and environmental rearing condition may modify these effects. The present study examined expression profiles of neurobiologically-relevant genes (i.e., neurotrophic factors, NMDA receptors, metabotropic glutamate receptors, synaptic function/plasticity, and transcription/gene regulation) in behaviorally naïve rats with perinatal exposure (i.e., gestation through weaning) to different levels of Pb (250, 750 and 1,500 ppm Pb acetate) in males and females raised in a non-enriched environment (standard housing without toys) or an enriched environment (large cage containing toys changed twice weekly). Unlike previous studies identifying gene changes following behavioral testing, which alters expression analysis, we identified both sex and environmental related changes in hippocampal genes following Pb exposure alone. The gene expression changes described may be associated with learning and memory and may pre-determine how cognitive profiles develop following Pb exposure.
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Affiliation(s)
- D W Anderson
- Dept. of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States.
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Block ML, Elder A, Auten RL, Bilbo SD, Chen H, Chen JC, Cory-Slechta DA, Costa D, Diaz-Sanchez D, Dorman DC, Gold DR, Gray K, Jeng HA, Kaufman JD, Kleinman MT, Kirshner A, Lawler C, Miller DS, Nadadur SS, Ritz B, Semmens EO, Tonelli LH, Veronesi B, Wright RO, Wright RJ. The outdoor air pollution and brain health workshop. Neurotoxicology 2012; 33:972-84. [PMID: 22981845 PMCID: PMC3726250 DOI: 10.1016/j.neuro.2012.08.014] [Citation(s) in RCA: 347] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 08/15/2012] [Accepted: 08/30/2012] [Indexed: 12/14/2022]
Abstract
Accumulating evidence suggests that outdoor air pollution may have a significant impact on central nervous system (CNS) health and disease. To address this issue, the National Institute of Environmental Health Sciences/National Institute of Health convened a panel of research scientists that was assigned the task of identifying research gaps and priority goals essential for advancing this growing field and addressing an emerging human health concern. Here, we review recent findings that have established the effects of inhaled air pollutants in the brain, explore the potential mechanisms driving these phenomena, and discuss the recommended research priorities/approaches that were identified by the panel.
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Affiliation(s)
- Michelle L Block
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Campus, Richmond, VA, USA.
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Toxic environmental chemicals: the role of reproductive health professionals in preventing harmful exposures. Am J Obstet Gynecol 2012; 207:164-73. [PMID: 22405527 DOI: 10.1016/j.ajog.2012.01.034] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 01/24/2012] [Accepted: 01/24/2012] [Indexed: 11/24/2022]
Abstract
Every pregnant woman in the United States is exposed to many and varied environmental chemicals. Rapidly accumulating scientific evidence documents that widespread exposure to environmental chemicals at levels that are encountered in daily life can impact reproductive and developmental health adversely. Preconception and prenatal exposure to environmental chemicals are of particular importance because they may have a profound and lasting impact on health across the life course. Thus, prevention of developmental exposures to environmental chemicals would benefit greatly from the active participation of reproductive health professionals in clinical and policy arenas.
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Cory-Slechta DA, Merchant-Borna K, Allen JL, Liu S, Weston D, Conrad K. Variations in the nature of behavioral experience can differentially alter the consequences of developmental exposures to lead, prenatal stress, and the combination. Toxicol Sci 2012; 131:194-205. [PMID: 22930682 DOI: 10.1093/toxsci/kfs260] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Behavioral experience (BE) can critically influence later behavior and brain function, but the central nervous system (CNS) consequences of most developmental neurotoxicants are examined in the absence of any such context. We previously demonstrated marked differences in neurotransmitter changes produced by developmental lead (Pb) exposure ± prenatal stress (PS) depending upon whether or not rats had been given BE (Cory-Slechta, D. A., Virgolini, M. B., Rossi-George, A., Weston, D., and Thiruchelvam, M. (2009). The current study examined the hypothesis that the nature of the BE itself would be a critical determinant of outcome in mice that had been continually exposed to 0 or 100 ppm Pb acetate in drinking water alone or in combination with prenatal restraint stress. Half of the offspring in each of the four resulting groups/gender were exposed to positively reinforced (food-rewarded Fixed Interval schedule-controlled behavior) or negatively reinforced (inescapable forced swim) BE. Brain monoamines and amino acids differed significantly in relation to BE, even in control animals, as did the trajectory of effects of Pb ± PS, particularly in frontal cortex, hippocampus (both genders), and midbrain (males). In males, Pb ± PS-related changes in neurotransmitters correlated with behavioral performance. These findings suggest that CNS consequences of developmental toxicants studied in the absence of a broader spectrum of BEs may not necessarily be predictive of human outcomes. Evaluating the role of specific BEs as a modulator of neurodevelopmental insults offers the opportunity to determine what specific BEs may ameliorate the associated impacts and can assist in establishing underlying neurobiological mechanisms.
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Affiliation(s)
- Deborah A Cory-Slechta
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
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35
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Sex and rearing condition modify the effects of perinatal lead exposure on learning and memory. Neurotoxicology 2012; 33:985-95. [PMID: 22542453 DOI: 10.1016/j.neuro.2012.04.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 04/01/2012] [Accepted: 04/12/2012] [Indexed: 11/20/2022]
Abstract
Developmental lead (Pb) exposure is associated with cognitive impairments in humans and rodents alike. In particular, impaired spatial learning and memory, as assessed using the Morris water maze (MWM), has been noted in developmentally Pb-exposed rats. Although sex and rearing environment can influence MWM performance in normal animals, the interactions of sex and rearing environment on the impact of developmental Pb exposure on hippocampal-dependent processes has not been well characterized. The present study examined the effects of perinatal exposure (i.e., gestation through weaning) to different levels of Pb (250, 750 and 1500 ppm Pb acetate in food) in males and females raised in a non-enriched environment (standard cage with 3 animals and no toys) or an enriched environment (large cage containing a variety of toys that were changed twice weekly). Testing in the MWM began at postnatal day 55. Behavioral outcomes were influenced by sex and rearing environment, with complex interactions with Pb exposure. In non-Pb exposed control animals, beneficial effects of environmental enrichment on spatial learning and memory were observed in males and females, with greater effects in females. Pb exposure in females mitigated at least some of the benefits of enrichment on learning, particularly at the lowest and highest exposure levels. In males, enrichment conferred a modest learning advantage and for the most part, Pb exposure did not affect this. However, in males with the highest Pb exposure, enrichment did help to overcome detrimental effects of Pb on learning. In females, any potential benefit to reference memory contributed by enrichment was muted by exposure to Pb and for the most part, this was not reproduced in males. Thus, there are complex interactions between sex, environment, and Pb exposure on spatial learning and memory. Environmental manipulation is a potential risk modifier of developmental Pb exposure and interacts with other factors including sex and amount of Pb exposure to affect the functional influences of Pb on the brain.
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Parental enrichment and offspring development: Modifications to brain, behavior and the epigenome. Behav Brain Res 2012; 228:294-8. [DOI: 10.1016/j.bbr.2011.11.036] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Revised: 11/24/2011] [Accepted: 11/26/2011] [Indexed: 11/22/2022]
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37
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Schneider JS, Mettil W, Anderson DW. Differential effect of postnatal lead exposure on gene expression in the hippocampus and frontal cortex. J Mol Neurosci 2011; 47:76-88. [PMID: 22160880 DOI: 10.1007/s12031-011-9686-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 11/24/2011] [Indexed: 11/29/2022]
Abstract
Although developmental lead exposure is known to have detrimental effects on a variety of cognitive functions that depend on the integrity of the hippocampus and frontal cortex, little is known about how low levels of lead exposure affect expression of key families of genes in these structures. The present study examined the effects of exposure to environmentally relevant levels of lead during the sensitive early post-weaning period in the rat on the expression profiles of a select number of neurobiologically relevant genes (i.e., genes for neurotrophic factors, NMDA receptors, metabotropic glutamate receptors, synaptic function/plasticity, cell signaling, and transcription/regulation) in the rat hippocampus and frontal cortex. Exposure to lead (180 and 375-ppm lead acetate in food for 30 days) significantly increased blood lead levels (5.8 to 10.3 μg/dl) and significantly affected expression of many of the genes examined. In many instances, lead exposure had different effects on the same gene depending on the brain region in which the expression of that gene was examined. Gene expression in the frontal cortex was often more sensitive to modification than gene expression in the hippocampus. These results suggest that even past infancy, exposures to low levels of lead can have significant effects on gene expression in the frontal cortex and the hippocampus with the potential to exert long-term effects on behavior and cognition.
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Affiliation(s)
- J S Schneider
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, 1020 Locust Street, 521 JAH, Philadelphia, PA 19107, USA.
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Schwartz J, Bellinger D, Glass T. Exploring potential sources of differential vulnerability and susceptibility in risk from environmental hazards to expand the scope of risk assessment. Am J Public Health 2011; 101 Suppl 1:S94-101. [PMID: 22021315 DOI: 10.2105/ajph.2011.300272] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Genetic factors, other exposures, individual disease states and allostatic load, psychosocial stress, and socioeconomic position all have the potential to modify the response to environmental exposures. Moreover, many of these modifiers covary with the exposure, leading to much higher risks in some subgroups. These are not theoretical concerns; rather, all these patterns have already been demonstrated in studies of the effects of lead and air pollution. However, recent regulatory impact assessments for these exposures have generally not incorporated these findings. Therefore, differential risk and vulnerability is a critically important but neglected area within risk assessment, and should be incorporated in the future.
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Affiliation(s)
- Joel Schwartz
- Department of Environmental Health and Epidemiology, Harvard School of Public Health, and Harvard Center for Risk Analysis, Harvard University, Boston, MA 02215, USA.
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Effects of increased opportunity for physical exercise and learning experiences on recognition memory and brain-derived neurotrophic factor levels in brain and serum of rats. Neuroscience 2011; 199:284-91. [PMID: 21854836 DOI: 10.1016/j.neuroscience.2011.08.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 07/19/2011] [Accepted: 08/04/2011] [Indexed: 01/29/2023]
Abstract
Studies with animal models showed that cellular, structural, and behavioral changes induced by environmental enrichment are related to increased levels of brain-derived neurotrophic factor (BDNF) in the brain. These evidence suggest that BDNF could be an interesting biomarker of the effects of lifestyle on cognition and other behavioral parameters in humans, mainly if the BDNF alterations in brain are accompanied by correspondent peripheral modifications, since human studies depend basically on the evaluation of this neurotrophin in serum or plasma. To test this hypothesis, we analyzed the effects of environmental enrichment on long-term memory for object recognition and on BDNF levels of hippocampus, frontal cortex, and serum of rats exposed to an experimental protocol that could be more easily translated to human intervention studies. Animals were maintained for 10 weeks in a social (standard laboratory conditions) or enriched (increased opportunity for physical exercise and learning experiences) condition. In the 7th week, they were submitted to behavioral testing (open field and novel object memory task), and at the end of the 10th week, they were killed and BDNF levels were analyzed. Animals maintained in the enriched condition showed enhanced performance on the memory task in the absence of any significant alteration in central or peripheral BDNF levels. The results of this study are important to highlight the need to develop experimental protocols using animal models that more closely resemble the characteristics of studies with humans and motivate more investigations to determine the conditions under which BDNF could be a biomarker of the effects of environment enrichment.
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Lewis AS, Sax SN, Wason SC, Campleman SL. Non-chemical stressors and cumulative risk assessment: an overview of current initiatives and potential air pollutant interactions. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2011; 8:2020-73. [PMID: 21776216 PMCID: PMC3138011 DOI: 10.3390/ijerph8062020] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/24/2011] [Accepted: 05/20/2011] [Indexed: 12/30/2022]
Abstract
Regulatory agencies are under increased pressure to consider broader public health concerns that extend to multiple pollutant exposures, multiple exposure pathways, and vulnerable populations. Specifically, cumulative risk assessment initiatives have stressed the importance of considering both chemical and non-chemical stressors, such as socioeconomic status (SES) and related psychosocial stress, in evaluating health risks. The integration of non-chemical stressors into a cumulative risk assessment framework has been largely driven by evidence of health disparities across different segments of society that may also bear a disproportionate risk from chemical exposures. This review will discuss current efforts to advance the field of cumulative risk assessment, highlighting some of the major challenges, discussed within the construct of the traditional risk assessment paradigm. Additionally, we present a summary of studies of potential interactions between social stressors and air pollutants on health as an example of current research that supports the incorporation of non-chemical stressors into risk assessment. The results from these studies, while suggestive of possible interactions, are mixed and hindered by inconsistent application of social stress indicators. Overall, while there have been significant advances, further developments across all of the risk assessment stages (i.e., hazard identification, exposure assessment, dose-response, and risk characterization) are necessary to provide a scientific basis for regulatory actions and effective community interventions, particularly when considering non-chemical stressors. A better understanding of the biological underpinnings of social stress on disease and implications for chemical-based dose-response relationships is needed. Furthermore, when considering non-chemical stressors, an appropriate metric, or series of metrics, for risk characterization is also needed. Cumulative risk assessment research will benefit from coordination of information from several different scientific disciplines, including, for example, toxicology, epidemiology, nutrition, neurotoxicology, and the social sciences.
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Affiliation(s)
- Ari S. Lewis
- Gradient, 20 University Road, Cambridge, MA 02138, USA; E-Mail:
| | - Sonja N. Sax
- Gradient, 20 University Road, Cambridge, MA 02138, USA; E-Mail:
| | - Susan C. Wason
- Department of Environmental Health, Harvard School of Public Health, 401 Park Drive, Boston, MA 02215, USA; E-Mail:
| | - Sharan L. Campleman
- Electric Power Research Institute, 3420 Hillview Ave., Palo Alto, CA 94304, USA; E-Mail:
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Low Lead Exposure During Foetal and Early Postnatal Life Impairs Passive Avoidance Learning in Adulthood in Rats. Arh Hig Rada Toksikol 2011; 62:147-53. [DOI: 10.2478/10004-1254-62-2011-2070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Low Lead Exposure During Foetal and Early Postnatal Life Impairs Passive Avoidance Learning in Adulthood in RatsThis follow-up study investigated the effects of low-level lead exposure during prenatal and early postnatal period on learning and memory in rats immediately after exposure has ceased at weaning and later in their adulthood. Male Wistar-derived rats were exposed to lead (as 0.2 % lead acetate solution) through their mothers during pregnancy and lactation until they were weaned. Mothers of control rats were given tap water during pregnancy and lactation. All pups were weaned on tap water at 21 days of age and were followed up until 120 days old. Low-level lead exposure did not affect their body weight at any time during the experiment. Blood lead in the exposed rats was significantly higher on postnatal day 22 and dropped to control values by day 120. Passive avoidance test showed impaired memory retention in the exposed rats on postnatal days 25 and 120. This suggests that exposure to low-lead levels during foetal and early postnatal development of brain tissue can cause memory impairment that lasts into adulthood.
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Burke MG, Miller MD. Practical guidelines for evaluating lead exposure in children with mental health conditions: molecular effects and clinical implications. Postgrad Med 2011; 123:160-8. [PMID: 21293095 DOI: 10.3810/pgm.2011.01.2256] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Children in the United States are exhibiting extremely high levels of attentional and learning disabilities. Although lead has been eliminated from many industrial products, children continue to come into contact with it, such as in toys and cosmetics. Lead exposure occurs most commonly in poor, urban populations, and can exacerbate psychiatric disorders associated with stress. We present 1) an overview of lead exposure; 2) a detailed summary of current research on the molecular synergy of toxicity caused by lead and stress; 3) a review of human studies that appear to correlate with these molecular findings, including understanding nutrition, environmental enrichment, and caregiving as risk modifiers; and 4) a systematic approach for mental health practitioners in managing children presenting with multiple symptoms and risk factors for mental health conditions. In this article, we review some of the clinical and scientific challenges that relate to the assessment and treatment of children presenting for mental health care who may have potential lead exposure.
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Affiliation(s)
- Mary G Burke
- Sutter Pacific Medical Foundation, Greenbrae, CA 94904, USA.
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Kiss P, Atlasz T, Szabadfi K, Horvath G, Griecs M, Farkas J, Matkovits A, Toth G, Lubics A, Tamas A, Gabriel R, Reglodi D. Comparison between PACAP- and enriched environment-induced retinal protection in MSG-treated newborn rats. Neurosci Lett 2010; 487:400-5. [PMID: 21050880 DOI: 10.1016/j.neulet.2010.10.065] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 10/25/2010] [Accepted: 10/27/2010] [Indexed: 10/18/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) and its receptors occur throughout the nervous system, including the retina. PACAP exerts diverse actions in the eye: it influences ocular blood flow, contraction of the ciliary muscle, and has retinoprotective effects. This effect has been proven in different models of retinal degeneration. We have previously shown that PACAP protects against monosodium-glutamate (MSG)-induced damage in neonatal rats. The beneficial effects of enriched environment, another neuroprotective strategy, have long been known. Environmental enrichment has been shown to decrease different neuronal injuries. It also influences the development of the visual system. We have recently demonstrated that significant neuroprotection can be achieved in MSG-induced retinal degeneration in animals kept in an enriched environment. Combination of neuroprotective strategies often results in increased protection. Therefore, the aim of the present study was to compare the two neuroprotective strategies alone and in combination therapy. We found that both PACAP and environmental enrichment led to a similar degree of retinal protection, but the two treatments together did not lead to increased protection: their effects were not additive.
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Affiliation(s)
- Peter Kiss
- Department of Anatomy, University of Pecs, 7624 Pecs, Szigeti u 12, Hungary.
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Cory-Slechta DA, Stern S, Weston D, Allen JL, Liu S. Enhanced learning deficits in female rats following lifetime pb exposure combined with prenatal stress. Toxicol Sci 2010; 117:427-38. [PMID: 20639260 DOI: 10.1093/toxsci/kfq221] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Pb (lead) exposure and stress are co-occurring risk factors (particularly in low socioeconomic communities) that also act on common biological substrates and produce common adverse outcomes, including cognitive impairments. This study sought to determine whether lifetime Pb exposure combined with prenatal stress would enhance the cognitive deficits independently associated with each of these risk factors and to explore associated mechanisms of any observed impairments. Learning was evaluated using a multiple schedule of repeated learning and performance in female rats subjected to lifetime Pb exposure (0 or 50 ppm Pb in drinking water beginning in dams 2 months prior to breeding; blood Pb levels ∼10 μg/dl), to prenatal restraint stress on gestational days 16 and 17, or to both. Blood Pb, corticosterone levels, brain monoamines, and hippocampal nerve growth factor levels were also measured. Sequence-specific learning deficits produced by Pb, particularly the number of responses to correctly learn response sequences, were further enhanced by stress, whereas performance measures were unimpaired. Statistical analyses indicated significant relationships among corticosterone levels, frontal cortex dopamine (DA), nucleus accumbens dopamine turnover, and total responses required to learn sequences. This study demonstrates that Pb and stress can act together to produce selective and highly condition-dependent deficits in learning in female rats that may be related to glucocorticoid-mediated interactions with mesocorticolimbic regions of brain. These findings also underscore the critical need to evaluate toxicants in the context of other risk factors pertinent to human diseases and disorders.
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Affiliation(s)
- Deborah A Cory-Slechta
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
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Bostrom N, Sandberg A. Cognitive enhancement: methods, ethics, regulatory challenges. SCIENCE AND ENGINEERING ETHICS 2009; 15:311-341. [PMID: 19543814 DOI: 10.1007/s11948-009-9142-5] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2006] [Accepted: 03/25/2009] [Indexed: 05/27/2023]
Abstract
Cognitive enhancement takes many and diverse forms. Various methods of cognitive enhancement have implications for the near future. At the same time, these technologies raise a range of ethical issues. For example, they interact with notions of authenticity, the good life, and the role of medicine in our lives. Present and anticipated methods for cognitive enhancement also create challenges for public policy and regulation.
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Affiliation(s)
- Nick Bostrom
- Future of Humanity Institute, Faculty of Philosophy & James Martin 21st Century School, Oxford University, Littlegate House, Oxford OX1 1PT, UK.
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Miranda ML, Kim D, Reiter J, Overstreet Galeano MA, Maxson P. Environmental contributors to the achievement gap. Neurotoxicology 2009; 30:1019-24. [PMID: 19643133 DOI: 10.1016/j.neuro.2009.07.012] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 07/07/2009] [Accepted: 07/20/2009] [Indexed: 11/29/2022]
Abstract
Extensive research shows that blacks, those of low socioeconomic status, and other disadvantaged groups continue to exhibit poorer school performance compared with middle and upper-class whites in the United States' educational system. Environmental exposures may contribute to the observed achievement gap. In particular, childhood lead exposure has been linked to a number of adverse cognitive outcomes. In previous work, we demonstrated a relationship between early childhood lead exposure and end-of-grade (EOG) test scores on a limited dataset. In this analysis, data from the North Carolina Childhood Lead Poisoning Prevention Program surveillance registry were linked to educational outcomes available through the North Carolina Education Research Data Center for all 100 counties in NC. Our objectives were to confirm the earlier study results in a larger population-level database, determine whether there are differences in the impact of lead across the EOG distribution, and elucidate the impact of cumulative childhood social and environmental stress on educational outcomes. Multivariate and quantile regression techniques were employed. We find that early childhood lead exposure is associated with lower performance on reading EOG test scores in a clear dose-response pattern, with the effects increasingly more pronounced in moving from the high end to the low end of the test score distribution. Parental educational attainment and family poverty status also affect EOG test scores, in a similar dose-response fashion, with the effects again most pronounced at the low end of the EOG test score distribution. The effects of environmental and social stressors (especially as they stretch out the lower tail of the EOG distribution) demonstrate the particular vulnerabilities of socioeconomically and environmentally disadvantaged children. Given the higher average lead exposure experienced by African American children in the United States, lead does in fact explain part of the achievement gap.
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Affiliation(s)
- Marie Lynn Miranda
- Children's Environmental Health Initiative, Nicholas School of the Environment, Duke University, Durham, NC 27708, USA.
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Experimental manipulations blunt time-induced changes in brain monoamine levels and completely reverse stress, but not Pb+/-stress-related modifications to these trajectories. Behav Brain Res 2009; 205:76-87. [PMID: 19631235 DOI: 10.1016/j.bbr.2009.06.040] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 05/30/2009] [Accepted: 06/04/2009] [Indexed: 12/13/2022]
Abstract
This study sought to further understand how environmental conditions influence the outcomes of early developmental insults. It compared changes in monoamine levels in frontal cortex, nucleus accumbens and striatum of male and female Long-Evans rat offspring subjected to maternal Pb exposure (0, 50 or 150ppm in drinking water from 2 months pre-breeding until pup weaning)+/-prenatal (PS) (restraint on GD16-17) or PS+offspring stress (OS; three variable stress challenges to young adults) determined at 2 months of age and at 6 months of age in littermates subsequently exposed either to experimental manipulations (EM: daily handling and performance on an operant fixed interval (FI) schedule of food reward), or to no experience (NEM; time alone). Time alone (NEM conditions), even in normal (control) animals, modified the trajectory of neurochemical changes between 2 and 6 months across brain regions and monoamines. EM significantly modified the NEM trajectories, and except NE and striatal DA, which increased, blunted the changes in monoamine levels that occurred over time alone. Pb+/-stress modified the trajectory of monoamine changes in both EM and NEM conditions, but these predominated under NEM conditions. Stress-associated modifications, occurring mainly with NEM OS groups, were fully reversed by EM procedures, while reversals of Pb+/-stress-associated modifications occurred primarily in nucleus accumbens, a region critical to mediation of FI response rates. These results extend the known environmental conditions that modify developmental Pb+/-stress insults, which is critical to ultimately understanding whether early insults lead to adaptive or maladaptive behavior and to devising behavioral therapeutic strategies. That time alone and a set of EM conditions typically used as outcome measures in intervention studies can themselves invoke neurochemical changes, moreover, has significant implications for experimental design of such studies.
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Healey N. Lead toxicity, vulnerable subpopulations and emergency preparedness. RADIATION PROTECTION DOSIMETRY 2009; 134:143-151. [PMID: 19398444 DOI: 10.1093/rpd/ncp068] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
This paper reviews some evidence of the toxic effects of lead (Pb) in the context of vulnerable subpopulations and emergency preparedness. Pb is ubiquitous in the environment and is used in many building materials. Environmental Pb concentrations and body burdens of Pb have been shown to increase following disasters. Pb is a systemic toxicant with no known beneficial biological function and, for several endpoints, no identified threshold of toxicity. The fetus, children, pregnant and elderly are particularly susceptible to some of the toxic effects of Pb. Pb exposures in infancy have been shown in vivo to produce an equal degree of neurobehavioural impairment as exposures of much longer duration at equivalent doses during adolescence. Evidence from animal bioassays indicates that the carcinogenic potency of perinatal Pb exposure may be about 3-fold higher than adult lifetime exposure at an equivalent dose. Animal assays show up to a 12-fold difference between fetal, neonatal and adult life stages in sensitivity to the immunological effects of Pb. Pb exposure is associated with increased risk of cardiovascular and cerebrovascular morbidity and mortality--health endpoints for which the elderly are at increased risk. Finally, endogenous and exogenous variables, such as psychological and physiological stress, dietary deficiencies and concomitant exposure to other chemical, biological and radiological hazards, can also potentially modify or potentiate the toxic effects of Pb. Because of the potential for concurrent influence of these modifying variables in a post-disaster environment, emergency response planners are encouraged to consider disaster victims and responders, as a whole, as a potentially vulnerable subpopulation.
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Affiliation(s)
- Norm Healey
- Azimuth Consulting Group Inc., Vancouver, BC, Canada.
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Abstract
PURPOSE OF REVIEW Although traditional disciplinary research theory and methods have focused separately on how social and physical environmental factors affect children's health, evolving research underscores important integrated effects. RECENT FINDINGS This review outlines the specific reasons why social determinants should be considered mainstream in children's environmental health research with particular focus on interactive effects between social and physical hazards. These include sensitivity of overlapping physiological systems, via epigenesis, programming, and plasticity to social and physical environmental moderation that may impact health across the life span; ways in which social environmental vulnerabilities moderate the effects of physical environmental factors, providing specific examples related to respiratory health and neurodevelopment; overlapping exposure distribution profiles; and relevance to pediatric health disparities. SUMMARY Because of the covariance across exposures, and evidence that social stress and other environmental toxins (e.g., pollutants, tobacco smoke) may influence common physiological pathways (e.g., oxidative stress, proinflammatory immune pathways, autonomic disruption), understanding the potential synergistic effects promises to more completely inform children's environmental health risk. Although this discussion focuses around the respiratory and neurological systems, these concepts extend more broadly to children's psychological and physical development.
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Affiliation(s)
- Rosalind J Wright
- The Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 181 Longwood Avenue, Boston, MA 02067, USA.
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