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Farmani R, Mehrpour O, Kooshki A, Nakhaee S. Exploring the link between toxic metal exposure and ADHD: a systematic review of pb and hg. J Neurodev Disord 2024; 16:44. [PMID: 39090571 PMCID: PMC11292919 DOI: 10.1186/s11689-024-09555-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Accepted: 07/02/2024] [Indexed: 08/04/2024] Open
Abstract
INTRODUCTION Attention-Deficit/Hyperactivity Disorder (ADHD) is a recognized neurodevelopmental disorder with a complex, multifactorial origin. Lead (Pb) and mercury (Hg) are highly toxic substances that can potentially impair brain development and have been implicated in the development of ADHD. This systematic review aims to analyze the epidemiological literature regarding the association between Pb and Hg exposure and the diagnosis of ADHD. METHODS From November 1983 to June 2, 2023, a comprehensive search was conducted in multiple databases and search engines, including PubMed, Web of Science, Scopus, and Google Scholar. Observational studies (case-control, cohort, and cross-sectional) measuring Pb and Hg levels in various biological samples (blood, hair, urine, nail, saliva, teeth, and bone) of children with ADHD or their parents and their association with ADHD symptoms were included. RESULTS Out of 2059 studies, 87 met the inclusion criteria and were included in this systematic review. Approximately two-thirds of the 74 studies investigating Pb levels in different biological samples reported associations with at least one subtype of ADHD. However, most studies examining Hg levels in various biological samples found no significant association with any ADHD subtype, although there were variations in exposure periods and diagnostic criteria. CONCLUSION The evidence gathered from the included studies supports an association between Pb exposure and the diagnosis of ADHD, while no significant association was found with Hg exposure. Importantly, even low levels of Pb were found to elevate the risk of ADHD. Further research is needed to explore the comprehensive range of risk factors for ADHD in children, considering its significance as a neurodevelopmental disorder.
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Affiliation(s)
- Reyhane Farmani
- Student Research Committee, Birjand University of Medical Sciences, Birjand, Iran
| | - Omid Mehrpour
- Michigan Poison & Drug Information Center, Wayne State University School of Medicine, Detroit, MI, USA
- Medical Toxicology and Drug Abuse Research Center (MTDRC), Birjand University of Medical Sciences, Birjand, Iran
| | - Alireza Kooshki
- Student Research Committee, Birjand University of Medical Sciences, Birjand, Iran
| | - Samaneh Nakhaee
- Medical Toxicology and Drug Abuse Research Center (MTDRC), Birjand University of Medical Sciences, Birjand, Iran.
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Klus JK, Thurston SW, Myers GJ, Watson GE, Rand MD, Love TM, Yeates AJ, Mulhern MS, McSorley EM, Strain JJ, Shamlaye CF, van Wijngaarden E. Postnatal methylmercury exposure and neurodevelopmental outcomes at 7 years of age in the Seychelles Child Development Study Nutrition Cohort 2. Neurotoxicology 2023; 99:115-119. [PMID: 37832849 PMCID: PMC10842381 DOI: 10.1016/j.neuro.2023.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/02/2023] [Accepted: 10/05/2023] [Indexed: 10/15/2023]
Abstract
BACKGROUND Consumption of fish yields many nutritional benefits, but also results in exposure to methylmercury (MeHg). The developing brain is known to be particularly susceptible to MeHg toxicity in high doses. However, the potential impact of low-level environmental exposure from fish consumption on children's neurodevelopment remains unclear. METHODS We investigated postnatal MeHg exposure at 7 years and its association with a battery of 17 neurodevelopmental outcomes in a subset of children (n = 376) from 1535 enrolled mother-child pairs in Nutrition Cohort 2 of the Seychelles Child Development Study (SCDS NC2). Each outcome was modeled in relation to postnatal MeHg exposure using linear regression, adjusting for prenatal MeHg exposure, levels of maternal polyunsaturated fatty acids (PUFA), and several other covariates known to be associated with neurodevelopmental outcomes. RESULTS Median postnatal MeHg exposure at 7 years was 2.5 ppm, while the median prenatal MeHg exposure was 3.5 ppm. We found no statistically significant associations between postnatal MeHg exposure and any of the 17 neurodevelopmental outcomes after adjusting for prenatal MeHg exposure and other covariates. CONCLUSIONS These findings are consistent with previous cross-sectional analyses of the SCDS Main Cohort. Continued follow-up of the entire NC2 cohort at later ages with repeated exposure measures is needed to further confirm these findings.
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Affiliation(s)
- Jonathan K Klus
- University of Rochester Medical Center, School of Medicine & Dentistry, Rochester, NY, USA
| | - Sally W Thurston
- University of Rochester Medical Center, School of Medicine & Dentistry, Rochester, NY, USA
| | - Gary J Myers
- University of Rochester Medical Center, School of Medicine & Dentistry, Rochester, NY, USA
| | - Gene E Watson
- University of Rochester Medical Center, School of Medicine & Dentistry, Rochester, NY, USA
| | - Matthew D Rand
- University of Rochester Medical Center, School of Medicine & Dentistry, Rochester, NY, USA
| | - Tanzy M Love
- University of Rochester Medical Center, School of Medicine & Dentistry, Rochester, NY, USA
| | - Alison J Yeates
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Northern Ireland, UK
| | - Maria S Mulhern
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Northern Ireland, UK
| | - Emeir M McSorley
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Northern Ireland, UK
| | - J J Strain
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Northern Ireland, UK
| | | | - Edwin van Wijngaarden
- University of Rochester Medical Center, School of Medicine & Dentistry, Rochester, NY, USA.
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Heng YY, Asad I, Coleman B, Menard L, Benki-Nugent S, Hussein Were F, Karr CJ, McHenry MS. Heavy metals and neurodevelopment of children in low and middle-income countries: A systematic review. PLoS One 2022; 17:e0265536. [PMID: 35358213 PMCID: PMC8970501 DOI: 10.1371/journal.pone.0265536] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 03/03/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The presence of harmful environmental exposures, which disproportionately affects low-and-middle income countries (LMICs), contributes to >25% of deaths and diseases worldwide and detrimentally affects child neurodevelopment. Few resources succinctly summarize the existing literature on this topic. Our objective is to systematically review and characterize the evidence regarding the relationship between heavy metals and neurodevelopment of children in LMICs. METHODS We conducted a medical librarian-curated search on multiple online databases to identify articles that included individuals <18 years living in a LMIC, quantitatively measured exposure to a heavy metal (either prenatal or postnatal), and used a standardized measurement of neurodevelopment (i.e. cognitive, language, motor, and behavior). Reviews, editorials, or case studies were excluded. Results were analyzed qualitatively, and quality was assessed. RESULTS Of the 18,043 screened articles, 298 full-text articles were reviewed, and 100 articles met inclusion criteria. The included studies represented data from 19 LMICs, only one of which was classified as a low-income country. Ninety-four percent of postnatal lead and all postnatal manganese studies showed a negative association with metal exposure and neurodevelopment, which were the strongest relationships among the metals studied. Postnatal exposure of mercury was associated with poor neurodevelopment in only half of studies. Limited data on postnatal arsenic and cadmium suggests an association with worse neurodevelopment. Findings were mixed for prenatal arsenic and lead, although some evidence supports that the neurotoxicity of lead was amplified in the presence of manganese. CONCLUSIONS AND POTENTIAL IMPACT We found that lead and manganese appear to consistently have a detrimental effect on the neurodevelopment of children, and more evidence is needed for mercury, arsenic, and cadmium. Better characterization of these effects can motivate and inform prioritization of much needed international policies and programs to reduce heavy metal exposures for young children within LMICs.
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Affiliation(s)
- Yi Yan Heng
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Iqra Asad
- School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, United States of America
| | - Bailey Coleman
- School of Health and Human Sciences, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, United States of America
| | - Laura Menard
- Ruth Lilly Medical Library, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Sarah Benki-Nugent
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Faridah Hussein Were
- Department of Chemistry, College of Biological and Physical Sciences of the University of Nairobi, Nairobi, Kenya
| | - Catherine J. Karr
- Department of Environmental and Occupational Health Sciences, Department of Pediatrics, University of Washington, Seattle, Washington, United States of America
| | - Megan S McHenry
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
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Kempton JW, Périssé ARS, Hofer CB, de Vasconcellos ACS, de Sousa Viana PV, de Oliveira Lima M, de Jesus IM, de Souza Hacon S, Basta PC. An Assessment of Health Outcomes and Methylmercury Exposure in Munduruku Indigenous Women of Childbearing Age and Their Children under 2 Years Old. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:10091. [PMID: 34639393 PMCID: PMC8508331 DOI: 10.3390/ijerph181910091] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 09/04/2021] [Accepted: 09/16/2021] [Indexed: 11/17/2022]
Abstract
In line with the 1000-day initiative and the Sustainable Development Goals (SDG) 2 and 3, we present a cross-sectional analysis of maternal health, infant nutrition, and methylmercury exposure within hard-to-reach indigenous communities in the state of Pará, Brazilian Amazon. We collected data from all women of childbearing age (i.e., 12-49) and their infants under two years old in three Munduruku communities (Sawré Muybu, Sawré Aboy, and Poxo Muybu) along the Tapajos River. We explored health outcomes through interviews, vaccine coverage and clinical assessment, and determined baseline hair methylmercury (H-Hg) levels. Hemoglobin, infant growth (Anthropometric Z scores) and neurodevelopment tests results were collected. We found that 62% of women of childbearing age exceeded the reference limit of 6.0 μg/g H-Hg (median = 7.115, IQR = 4.678), with the worst affected community (Sawré Aboy) registering an average H-Hg concentration of 12.67 μg/g. Half of infants aged under 24 months presented with anemia. Three of 16 (18.8%) infants presented H-Hg levels above 6.0 µg/g (median: 3.88; IQR = 3.05). Four of the 16 infants were found to be stunted and 38% of women overweight, evidencing possible nutritional transition. No infant presented with appropriate vaccination coverage for their age. These communities presented with an estimated Infant Mortality Rate (IMR) of 86.7/1000 live births. The highest H-Hg level (19.6 µg/g) was recorded in an 11-month-old girl who was found to have gross motor delay and anemia. This already vulnerable indigenous Munduruku community presents with undernutrition and a high prevalence of chronic methylmercury exposure in women of childbearing age. This dual public health crisis in the context of wider health inequalities has the potential to compromise the development, health and survival of the developing fetus and infant in the first two critical years of life. We encourage culturally sensitive intervention and further research to focus efforts.
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Affiliation(s)
| | - André Reynaldo Santos Périssé
- Departamento de Endemias Samuel Pessoa, Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz (ENSP/Fiocruz), Rua Leopoldo Bulhões, 1480, Manguinhos, Rio de Janeiro 21041-210, Brazil; (A.R.S.P.); (S.d.S.H.)
| | - Cristina Barroso Hofer
- Instituto de Pediatria e Puericultura Martagão Gesteira, Faculdade de Medicina, Universidade Federal do Rio de Janeiro (UFRJ), Rua Bruno Lobo, 50, Cidade Universitária, Rio de Janeiro 21941-912, Brazil;
| | - Ana Claudia Santiago de Vasconcellos
- Laboratório de Educação Profissional em Vigilância em Saúde, Escola Politécnica de Saúde Joaquim Venân-cio, Fundação Oswaldo Cruz (EPSJV/Fiocruz), Av. Brasil, 4365, Manguinhos, Rio de Janeiro 21040-900, Brazil;
| | - Paulo Victor de Sousa Viana
- Centro de Referência Professor Hélio Fraga, Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz (CRPHF/ENSP/Fiocruz), Estrada de Curicica, 2000, Curicica, Rio de Janeiro 22780-195, Brazil;
| | - Marcelo de Oliveira Lima
- Seção de Meio Ambiente, Instituto Evandro Chagas, Secretaria de Vigilância em Saúde, Ministério da Saúde (SEAMB/IEC/SVS/MS), Rodovia BR-316 km 7 s/n, Levilândia 67030-000, Brazil; (M.d.O.L.); (I.M.d.J.)
| | - Iracina Maura de Jesus
- Seção de Meio Ambiente, Instituto Evandro Chagas, Secretaria de Vigilância em Saúde, Ministério da Saúde (SEAMB/IEC/SVS/MS), Rodovia BR-316 km 7 s/n, Levilândia 67030-000, Brazil; (M.d.O.L.); (I.M.d.J.)
| | - Sandra de Souza Hacon
- Departamento de Endemias Samuel Pessoa, Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz (ENSP/Fiocruz), Rua Leopoldo Bulhões, 1480, Manguinhos, Rio de Janeiro 21041-210, Brazil; (A.R.S.P.); (S.d.S.H.)
| | - Paulo Cesar Basta
- Departamento de Endemias Samuel Pessoa, Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz (ENSP/Fiocruz), Rua Leopoldo Bulhões, 1480, Manguinhos, Rio de Janeiro 21041-210, Brazil; (A.R.S.P.); (S.d.S.H.)
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Branco V, Aschner M, Carvalho C. Neurotoxicity of mercury: an old issue with contemporary significance. ADVANCES IN NEUROTOXICOLOGY 2021; 5:239-262. [PMID: 34263092 PMCID: PMC8276940 DOI: 10.1016/bs.ant.2021.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Mercury exerts a variety of toxic effects, depending on the specific compound and route of exposure. However, neurotoxicity in virtue of its consequence to health causes the greatest concern for toxicologists. This is particularly true regarding fetal development, where neurotoxic effects are much more severe than in adults, and the toxicity threshold is lower. Here, we review the major concepts regarding the neurotoxicity of mercury compounds (mercury vapor; methylmercury and ethylmercury), from exposure routes to toxicokinetic particularities leading to brain deposition and the development of neurotoxic effects. Albeit research on the neurotoxicity of mercury compounds has significantly advanced from the second half of the twentieth century onwards, several grey areas regarding the mechanism of toxicity still exist. Thus, we emphasize research advances during the last two decades concerning the molecular interactions of mercury which cause neurotoxic effects. Highlights include the disruption of glutamate signaling and excitotoxicity resulting from exposure to mercury and the interaction with redox active residues such as cysteines and selenocysteines which are the premise accounting for the disruption of redox homeostasis caused by mercurials. We also address how immunotoxic effects at the CNS, namely microglia and astrocyte activation modulate developmental neurotoxicity, a major topic in contemporary research.
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Affiliation(s)
- Vasco Branco
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, USA
| | - Cristina Carvalho
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
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Santos-Sacramento L, Arrifano GP, Lopes-Araújo A, Augusto-Oliveira M, Albuquerque-Santos R, Takeda PY, Souza-Monteiro JR, Macchi BM, do Nascimento JLM, Lima RR, Crespo-Lopez ME. Human neurotoxicity of mercury in the Amazon: A scoping review with insights and critical considerations. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 208:111686. [PMID: 33396018 DOI: 10.1016/j.ecoenv.2020.111686] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/24/2020] [Accepted: 11/17/2020] [Indexed: 06/12/2023]
Abstract
Human exposure to mercury is a major public health concern, causing neurological outcomes such as motor and visual impairment and learning disabilities. Currently, human exposure in the Amazon is among the highest in the world. A recent systematic review (doi:10.1016/j.jtemb.2018.12.001), however, highlighted the lack of high-quality studies on mercury-associated neurotoxicity. There is, therefore, a need to improve research and much to still learn about how exposure correlates with disease. In this review, we discuss studies evaluating the associations between neurological disturbances and mercury body burden in Amazonian populations, to generate recommendations for future studies. A systematic search was performed during July 2020, in Pubmed/Medline, SCOPUS and SCIELO databases with the terms (mercury*) and (Amazon*). Four inclusion criteria were used: original article (1), with Amazonian populations (2), quantifying exposure (mercury levels) (3), and evaluating neurological outcomes (4). The extracted data included characteristics (as year or origin of authorship) and details of the research (as locations and type of participants or mercury levels and neurological assessments). Thirty-four studies, most concentrated within three main river basins (Tapajós, Tocantins, and Madeira) and related to environmental exposure, were found. Mercury body burden was two to ten times higher than recommended and main neurological findings were cognitive, vision, motor, somatosensory and emotional deficits. Important insights are described that support novel approaches to researching mercury exposure and intoxication, as well as prevention and intervention strategies. As a signatory country to the Minamata Convention, Brazil has the opportunity to play a central role in improving human health and leading the research on mercury intoxication.
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Affiliation(s)
- Leticia Santos-Sacramento
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA 66075-110, Brazil.
| | - Gabriela P Arrifano
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA 66075-110, Brazil.
| | - Amanda Lopes-Araújo
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA 66075-110, Brazil.
| | - Marcus Augusto-Oliveira
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA 66075-110, Brazil.
| | - Raquel Albuquerque-Santos
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA 66075-110, Brazil.
| | - Priscila Y Takeda
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA 66075-110, Brazil.
| | | | - Barbarella M Macchi
- Laboratório de Neuroquímica Molecular e Celular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA 66075-110, Brazil.
| | - José Luiz M do Nascimento
- Laboratório de Neuroquímica Molecular e Celular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA 66075-110, Brazil; Programa de Pós-graduação em Ciências Farmacêuticas, Departamento de Ciências Biológicas e da Saúde, Universidade Federal do Amapá (UNIFAP), 68903-419 Macapá, AP, Brazil.
| | - Rafael R Lima
- Laboratório de Biologia Estrutural e Funcional, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA 66075-110, Brazil.
| | - Maria Elena Crespo-Lopez
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA 66075-110, Brazil.
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Reuben A, Frischtak H, Berky A, Ortiz EJ, Morales AM, Hsu‐Kim H, Pendergast LL, Pan WK. Elevated Hair Mercury Levels Are Associated With Neurodevelopmental Deficits in Children Living Near Artisanal and Small-Scale Gold Mining in Peru. GEOHEALTH 2020; 4:e2019GH000222. [PMID: 32490301 PMCID: PMC7240868 DOI: 10.1029/2019gh000222] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 02/10/2020] [Accepted: 03/11/2020] [Indexed: 05/08/2023]
Abstract
Children living near artisanal and small-scale gold mining (ASGM) are at risk of exposure to mercury, a neurotoxicant. It is not certain whether such exposures are harming development, as they occur in underresourced contexts entwined with other stressors, such as malnutrition and enteric infection. This study sought to investigate the association between hair-mercury levels and visual-motor, cognitive, and physical development among children living near ASGM in the Peruvian Amazon. Total hair-mercury levels were measured in 164 children ages 5-12 living in Madre de Dios, Peru. Primary outcomes included Visual-Motor Integration assessed via the Beery-VMI Developmental Test, General Cognitive Ability assessed via the Batería-III Woodcock-Munoz (Spanish-language Woodcock-Johnson Tests of Cognitive Abilities), and Physical Health assessed via anthropometry/hemoglobin counts. Mean (SD) hair-mercury level was 2.06 (2.43) μg/g. Fifty-four children (32.9%) had hair-mercury levels above the World Health Organization reference level of 2.0 μg/g. After controlling for sex, child age, maternal education, and family socioeconomic status, each one unit increase in log hair-mercury level was associated with a 1.01 unit decrease in Visual-Motor Integration (95%CI: -2.06, 0.05, p = 0.061), a 2.59 unit decrease in General Cognitive Ability (95%CI: -4.52, -0.66, p = 0.012), and a 2.43 unit decrease in Physical Health (95%CI: -5.34, 0.49, p = 0.096). After adjustment for covariates, children with hair-mercury levels exceeding the World Health Organization reference level scored 4.68 IQ points lower in Cognitive Ability than their peers. Mercury exposures related to ASGM may be harming child development in the Peruvian Amazon. Children in this region may benefit from intervention to reach their full developmental potential.
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Affiliation(s)
- Aaron Reuben
- Department of Psychology and NeuroscienceDuke UniversityDurhamNCUSA
| | | | - Axel Berky
- Global Health InstituteDuke UniversityDurhamNCUSA
- Nicholas School of the EnvironmentDuke UniversityDurhamNCUSA
| | - Ernesto J. Ortiz
- Global Health InstituteDuke UniversityDurhamNCUSA
- Nicholas School of the EnvironmentDuke UniversityDurhamNCUSA
| | - Ana Maria Morales
- Centro de Estudios, Investigaciones y Servicios en Salud Publica (CENSAP)Puerto MaldonadoPeru
| | - Heileen Hsu‐Kim
- Nicholas School of the EnvironmentDuke UniversityDurhamNCUSA
| | - Laura L. Pendergast
- Department of Psychological Studies in EducationTemple UniversityPhiladelphiaPAUSA
| | - William K. Pan
- Global Health InstituteDuke UniversityDurhamNCUSA
- Nicholas School of the EnvironmentDuke UniversityDurhamNCUSA
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Abdelzaher LA, Hussein OA, Ashry IEM. The Novel Potential Therapeutic Utility of Montelukast in Alleviating Autistic Behavior Induced by Early Postnatal Administration of Thimerosal in Mice. Cell Mol Neurobiol 2020; 41:129-150. [PMID: 32303879 DOI: 10.1007/s10571-020-00841-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 04/01/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND AND AIM: Thimerosal (THIM) is a mercury-containing preservative widely used in many biological and medical products including many vaccines. It has been accused of being a possible etiological factor for some neurodevelopmental disorders such as autistic spectrum disorders (ASDs). In our study, the potential therapeutic effect of montelukast, a leukotriene receptor antagonist used to treat seasonal allergies and asthma, on THIM mice model (ASDs model) was examined. METHODOLOGY Newborn mice were randomly distributed into three groups: (Group 1) Control (Cont.) group received saline injections. (Group 2) THIM-treated (THIM) group received THIM intramuscular (IM) at a dose of 3000 μg Hg/kg on postnatal days 7, 9, 11, and 15. (Group 3) Montelukast-treated (Monte) group received THIM followed by montelukast sodium (10 mg/kg/day) intraperitoneal (IP) for 3 weeks. Mice were evaluated for growth development, social interactions, anxiety, locomotor activity, and cognitive function. Brain histopathology, alpha 7 nicotinic acetylcholine receptors (α7nAChRs), nuclear factor kappa B p65 (NF-κB p65), apoptotic factor (Bax), and brain injury markers were evaluated as well. RESULTS THIIM significantly impaired social activity and growth development. Montelukast mitigated THIM-induced social deficit probably through α7nAChRs upregulation, NF-κB p65, Bax, and brain injury markers downregulation, thus suppressing THIM-induced neuronal toxicity and inflammation. CONCLUSION Neonatal exposure to THIM can induce growth retardation and abnormal social interactions similar to those observed in ASDs. Some of these abnormalities could be ameliorated by montelukast via upregulation of α7nAChRs that inhibited NF-κB activation and significant suppression of neuronal injury and the associated apoptosis.
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Affiliation(s)
- Lobna A Abdelzaher
- Department of Pharmacology, Faculty of Medicine, Assiut University, Assiut, Egypt.
| | - Ola A Hussein
- Department of Histology, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - I E M Ashry
- Department of Pharmacology, Faculty of Medicine, Assiut University, Assiut, Egypt
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Ramos A, Dos Santos MM, de Macedo GT, Wildner G, Prestes AS, Masuda CA, Dalla Corte CL, Teixeira da Rocha JB, Barbosa NV. Methyl and Ethylmercury elicit oxidative stress and unbalance the antioxidant system in Saccharomyces cerevisiae. Chem Biol Interact 2020; 315:108867. [PMID: 31672467 DOI: 10.1016/j.cbi.2019.108867] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 10/07/2019] [Accepted: 10/21/2019] [Indexed: 11/19/2022]
Abstract
Methylmercury (MeHg) and Ethylmercury (EtHg) are toxic to the central nervous system. Human exposure to MeHg and EtHg results mainly from the consumption of contaminated fish and thimerosal-containing vaccines, respectively. The mechanisms underlying the toxicity of MeHg and EtHg are still elusive. Here, we compared the toxic effects of MeHg and EtHg in Saccharomyces cerevisiae (S. cerevisiae) emphasizing the involvement of oxidative stress and the identification of molecular targets from antioxidant pathways. Wild type and mutant strains with deleted genes for antioxidant defenses, namely: γ-glutamylcysteine synthetase, glutathione peroxidase, catalase, superoxide dismutase, mitochondrial peroxiredoxin, cytoplasmic thioredoxin, and redox transcription factor Yap1 were used to identify potential pathways and proteins from cell redox system targeted by MeHg and EtHg. MeHg and EtHg inhibited cell growth, decreased membrane integrity, and increased the granularity and production of reactive species (RS) in wild type yeast. The mutants were predominantly less tolerant of mercurial than wild type yeast. But, as the wild strain, mutants exhibited higher tolerance to MeHg than EtHg. Our results indicate the involvement of oxidative stress in the cytotoxicity of MeHg and EtHg and reinforce S. cerevisiae as a suitable model to explore the mechanisms of action of electrophilic toxicants.
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Affiliation(s)
- Angelica Ramos
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Matheus M Dos Santos
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Gabriel T de Macedo
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Guilherme Wildner
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Alessandro S Prestes
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Claudio A Masuda
- Instituto de Bioquímica Médica Leopoldo De Meis, Universidade Federal do Rio de Janeiro, RJ, Brazil
| | | | | | - Nilda V Barbosa
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
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Dórea JG. Multiple low-level exposures: Hg interactions with co-occurring neurotoxic substances in early life. Biochim Biophys Acta Gen Subj 2018; 1863:129243. [PMID: 30385391 DOI: 10.1016/j.bbagen.2018.10.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/01/2018] [Accepted: 10/19/2018] [Indexed: 12/11/2022]
Abstract
All chemical forms of Hg can affect neurodevelopment; however, low levels of organic Hg (methylmercury-MeHg and ethylmercury-EtHg in Thimerosal-containing vaccines, hereafter 'TCV') exposures during early life (pregnancy and lactation) co-occur with other environmental neurotoxic substances. These neurotoxicants may act in parallel, synergistically, or antagonistically to Hg. Nevertheless, the risks of neurotoxicity associated with multiple neuro-toxicants depend on type, time, combinations of exposure, and environmental and/or genetic-associated factors. Neurological developmental disorders, delays in cognition and behavioral outcomes associated with multiple exposures (which include Hg) may show transient or lasting outcomes depending on constitutional and/or environmental factors that can interact to neutralize, aggravate or attenuate these effects; often these studies are challenging to interpret. During pregnancy and lactation, fish-MeHg exposure is frequently confounded with the opposing effects of neuroactive nutrients (in fish) that lead to positive, negative, or no effects on neurobehavioral tests. In infancy, exposures to acute binary mixtures (TCV- EtHg and Al-adjuvants in infant immunizations) are associated with increased risks of tics and other developmental disorders. Despite the certitude that promulgates single environmental neurotoxicants, empirical comparisons of combined exposures indicate that Hg-related outcome is uneven. Hg in combination with other neurotoxic mixtures may elevate risks of neurotoxicity, but these risks arise in circumstances that are not yet predictable. Therefore, to achieve the goals of the Minamata treaty and to safeguard the health of children, low levels of mercury exposure (in any chemical form) needs to be further reduced whether the source is environmental (air- and food-borne) or iatrogenic (pediatric TCVs).
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Affiliation(s)
- José G Dórea
- Universidade de Brasília, Brasília 70919-970, DF, Brazil..
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11
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Dórea JG. Low-dose Thimerosal (ethyl-mercury) is still used in infants` vaccines: Should we be concerned with this form of exposure? J Trace Elem Med Biol 2018; 49:134-139. [PMID: 29895363 DOI: 10.1016/j.jtemb.2018.05.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 05/16/2018] [Indexed: 12/25/2022]
Abstract
In developing countries, Thimerosal-containing vaccines (TCV) are the main causes of organic Hg exposure for newborns, neonates, and infants immunized with TCV. This article addresses early-life exposure to this unique organic mercury compound (ethylmercury-EtHg) and the risks of its exposure. English language studies pertaining to Thimerosal/EtHg toxicity and exposure during early life were searched in PubMed; and, those publications judged to be relevant to the topic of this review were selected. The risk from the neurotoxic effects of pre- and post-natal Hg exposures depend, in part, on aggravating or attenuating environmental and/or genetic-associated factors. Health authorities in charge of controlling infectious disease dismiss the toxicology of mercury (immunological and subtle neurological effects as insignificant) related to low-dose Thimerosal. The review addresses the evidence that brings into question the safety of Thimerosal that is still present in vaccines given to pregnant women, infants, and children in developing countries, and recognizes the ethical imperative to extend the use of Thimerosal-free vaccines to developing countries, not just developed countries.
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Affiliation(s)
- José G Dórea
- Health Sciences, Universidade de Brasília, Brasília, 70919-970, DF, Brazil.
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12
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Sampaio GSA, Oliveira KRHM, Kauffmann N, do Nascimento JLM, Souza GS, Gomes BD, de Lima SMA, Silveira LCL, Rocha FAF, Herculano AM. Methylmercury alters the number and topography of NO-synthase positive neurons in embryonic retina: Protective effect of alpha-tocopherol. Toxicol In Vitro 2018; 53:89-98. [PMID: 30075186 DOI: 10.1016/j.tiv.2018.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 06/25/2018] [Accepted: 07/30/2018] [Indexed: 10/28/2022]
Abstract
Vertebrate retina has been shown to be an important target for mercury toxicity and very studies have shown the effect of mercury on the retinal ontogenesis. The nitrergic system plays an important role in the retinal development. The current work studied the effects of methylmercury (MeHg) exposure on the NO-synthase positive neurons (NADPH-diaphorase neurons or NADPH-d+) of the chick retinal ganglion cell layer at embryonic E15 and postnatal P1 days. Retinal flat mounts were stained for NADPH-diaphorase histochemistry and mosaic properties of NADPH-d + were studied by plotting isodensity maps and employing density recovery profile technique. It was also evaluated the protective effect of alpha-tocopherol treatment on retinal tissues exposed to MeHg. MeHg exposure decreased the density of NADPH-d + neurons and altered cell mosaic properties at E15 but had very little or no effect at P1 retinas. Alpha-tocopherol has a protective effect against MeHg exposure at E15. MeHg alterations and alpha-tocopherol protective effect in embryonic retinas were demonstrated to be at work in experimental conditions. MeHg effect in the early phases of visual system development in natural conditions might use the nitrergic pathway and supplementary diet could have a protective effect. At later stages, this mechanism seems to be naturally protected.
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Affiliation(s)
- Gabriela S A Sampaio
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil
| | | | - Nayara Kauffmann
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil
| | - José Luiz M do Nascimento
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil; Universidade Ceuma, São Luís, Maranhão, Brazil
| | - Givago S Souza
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil; Núcleo de Medicina Tropical, Universidade Federal do Pará, Belém, Pará, Brazil
| | - Bruno D Gomes
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil
| | | | - Luiz Carlos L Silveira
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil; Núcleo de Medicina Tropical, Universidade Federal do Pará, Belém, Pará, Brazil; Universidade Ceuma, São Luís, Maranhão, Brazil
| | | | - Anderson M Herculano
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
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13
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Oliveira CS, Nogara PA, Ardisson-Araújo DMP, Aschner M, Rocha JBT, Dórea JG. Neurodevelopmental Effects of Mercury. ADVANCES IN NEUROTOXICOLOGY 2018; 2:27-86. [PMID: 32346667 PMCID: PMC7188190 DOI: 10.1016/bs.ant.2018.03.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The toxicology of mercury (Hg) is of concern since this metal is ubiquitously distributed in the environment, and living organisms are routinely exposed to Hg at low to high levels. The toxic effects of Hg are well studied and it is known that they may differ depending on the Hg chemical species. In this chapter, we emphasize the neurotoxic effects of Hg during brain development. The immature brain is more susceptible to Hg exposure, since all the Hg chemical forms, not only the organic ones, can harm it. The possible consequences of Hg exposure during the early stages of development, the additive effects with other co-occurring neurotoxicants, and the known mechanisms of action and targets will be addressed in this chapter.
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Affiliation(s)
- Cláudia S Oliveira
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Pablo A Nogara
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Daniel M P Ardisson-Araújo
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Laboratório de Virologia de Insetos, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, NY, USA
| | - João B T Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - José G Dórea
- Professor Emeritus, Faculdade de Ciências da Saúde, Universidade de Brasília, Brasília, DF, Brazil
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14
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The risk of neurodevelopmental disorders following Thimerosal-containing Hib vaccine in comparison to Thimerosal-free Hib vaccine administered from 1995 to 1999 in the United States. Int J Hyg Environ Health 2018; 221:677-683. [DOI: 10.1016/j.ijheh.2018.03.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 12/27/2017] [Accepted: 03/13/2018] [Indexed: 01/24/2023]
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dos Santos Freitas J, da Costa Brito Lacerda EM, da Silva Martins ICV, Rodrigues D, Bonci DMO, Cortes MIT, Corvelo TCO, Ventura DF, de Lima Silveira LC, da Conceição Nascimento Pinheiro M, da Silva Souza G. Cross-sectional study to assess the association of color vision with mercury hair concentration in children from Brazilian Amazonian riverine communities. Neurotoxicology 2018; 65:60-67. [DOI: 10.1016/j.neuro.2018.02.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/06/2018] [Accepted: 02/06/2018] [Indexed: 12/18/2022]
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Cerbino MR, Vieira JCS, Braga CP, Oliveira G, Padilha IF, Silva TM, Zara LF, Silva NJ, Padilha PM. Metalloproteomics Approach to Analyze Mercury in Breast Milk and Hair Samples of Lactating Women in Communities of the Amazon Basin, Brazil. Biol Trace Elem Res 2018; 181:216-226. [PMID: 28547667 DOI: 10.1007/s12011-017-1057-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 05/16/2017] [Indexed: 01/25/2023]
Abstract
Mercury is a potentially toxic element that is present in the environment of the Brazilian Amazon and is responsible for adverse health effects in humans. This study sought to assess possible protein biomarkers of mercury exposure in breast milk samples from lactating women in the Madeira and Negro Rivers in the Brazilian Amazon. The mercury content of hair samples of lactating women was determined, and the proteome of breast milk samples was obtained using two-dimensional electrophoresis after protein precipitation with acetone. Mercury measurements of protein spots obtained via protein fractionation were performed by graphite furnace atomic absorption spectrometry (GFAAS), and it was observed that mercury is linked to proteins with molecular masses in the range of 14-26 kDa. The total mercury concentration was also determined by GFAAS in unprocessed milk, lyophilized milk, and protein pellets, with the purpose of determining the mercury mass balance in relation to the concentration of this element in milk and pellets. Approximately 85 to 97% of mercury present in the lyophilized milk from samples of lactating women of the Madeira River is bound in the protein fraction. From lactating women of the Negro River, approximately 49% of the total mercury is bound in the protein fraction, and a difference of 51% is bound in the lipid fraction.
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Affiliation(s)
- M R Cerbino
- Pontifical Catholic University of Goiás (PUC), Goiânia, GO, Brazil
| | | | - C P Braga
- Institute of Biosciences, São Paulo State University (UNESP), Botucatu, Brazil
| | - G Oliveira
- Institute of Biosciences, São Paulo State University (UNESP), Botucatu, Brazil
| | - I F Padilha
- São Paulo State University (UNESP), São José do Rio Preto, SP, Brazil
| | - T M Silva
- College of Planaltina, University of Brasília (UnB), Brasília, Federal District, Brazil
| | - L F Zara
- College of Planaltina, University of Brasília (UnB), Brasília, Federal District, Brazil
| | - N J Silva
- Pontifical Catholic University of Goiás (PUC), Goiânia, GO, Brazil
| | - P M Padilha
- Institute of Biosciences, São Paulo State University (UNESP), Botucatu, Brazil
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17
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The Putative Role of Environmental Mercury in the Pathogenesis and Pathophysiology of Autism Spectrum Disorders and Subtypes. Mol Neurobiol 2017; 55:4834-4856. [DOI: 10.1007/s12035-017-0692-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 07/13/2017] [Indexed: 01/28/2023]
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18
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Bansa DK, Awua AK, Boatin R, Adom T, Brown-Appiah EC, Amewosina KK, Diaba A, Datoghe D, Okwabi W. Cross-sectional assessment of infants' exposure to toxic metals through breast milk in a prospective cohort study of mining communities in Ghana. BMC Public Health 2017; 17:505. [PMID: 28545513 PMCID: PMC5445457 DOI: 10.1186/s12889-017-4403-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 05/09/2017] [Indexed: 11/10/2022] Open
Abstract
Background Although breastfeeding of infants is recommended globally, the fact that maternal toxic metal stores are mobilised into breast milk implies infants, whose mothers live and work in mining communities, are at risk of multiple exposure to mining related toxic metals, such as Lead (Pb), Mercury (Hg), Cadmium (Cd) and Arsenic (As), through breast milk intake, in addition to in utero exposure. Method A total of 114 mother-baby pairs, recruited from two community hospitals servicing mining communities in two different regions in Ghana (57 each), were involved in this study. When the babies were 3 months old, the amount of breast milk intake, concentrations of selected toxic metals in the breast milk and therefore the amount of toxic metals exposure through breast milk were determined. The study also, determined the amount of these toxic metals in the hair and urine of each mother-baby pair at 3 months postpartum. Results Based on the amounts of milk intake and non-milk oral intakes (geometric mean of 0.701 (95% CL 0.59–0.81) Kg/day and median of 0.22 Kg/day respectively), 90% of the babies were determined to have been exclusively breastfed. The amounts of most of the toxic metals in breast milk were higher than the WHO set limits and for 46.4%, 33.3% and 4.4% of the babies, their intake of As, Hg and Pb respectively were above the WHO provisional tolerable daily intake (PTDI) values. Conclusion An appreciable proportion of babies living within the communities served by the Mangoasi Community Hospital in the Obuasi Municipality of the Ashanti Region and the Dompime Health Centre in the Tarkwa Municipality of the Western Region were exposed to Hg, As and Pb through breast milk in excess of what they should and these may have health implication for the infants and therefore calls for interventions.
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Affiliation(s)
- David Kwaku Bansa
- Nutrition Research Centre, Radiological and Medical Sciences Research Institute, Ghana Atomic Energy Commission, Accra, Ghana
| | - Adolf Kofi Awua
- Cellular and Clinical Research Centre, Radiological and Medical Sciences Research Institute, Ghana Atomic Energy Commission, Accra, Ghana.
| | - Rose Boatin
- Nutrition Research Centre, Radiological and Medical Sciences Research Institute, Ghana Atomic Energy Commission, Accra, Ghana
| | - Theodosia Adom
- Nutrition Research Centre, Radiological and Medical Sciences Research Institute, Ghana Atomic Energy Commission, Accra, Ghana
| | - Edward Christian Brown-Appiah
- Nutrition Research Centre, Radiological and Medical Sciences Research Institute, Ghana Atomic Energy Commission, Accra, Ghana
| | - Kennedy Kwame Amewosina
- Nutrition Research Centre, Radiological and Medical Sciences Research Institute, Ghana Atomic Energy Commission, Accra, Ghana
| | - Akusika Diaba
- Nutrition Research Centre, Radiological and Medical Sciences Research Institute, Ghana Atomic Energy Commission, Accra, Ghana
| | - Dominic Datoghe
- Nutrition Research Centre, Radiological and Medical Sciences Research Institute, Ghana Atomic Energy Commission, Accra, Ghana
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Dórea JG. Abating Mercury Exposure in Young Children Should Include Thimerosal-Free Vaccines. Neurochem Res 2017; 42:2673-2685. [PMID: 28439753 DOI: 10.1007/s11064-017-2277-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 04/11/2017] [Accepted: 04/19/2017] [Indexed: 12/27/2022]
Abstract
Pediatric immunization is essential to prevent, control and eradicate children`s infectious diseases. Newborns and infants in less developed countries have a concentrated schedule of Thimerosal-containing vaccines (TCVs); pregnant mothers are also immunized with TCVs. Metabolic changes during early development are demonstrably an important risk factor for ethylmercury (EtHg) effects on neurodevelopment, while exposure to Thimerosal sensitizes susceptible individuals to life-long contact dermatitis. Concerns regarding toxicity of Hg have moved rich nations to withdraw it from medicines and, in particular, Thimerosal from pediatric vaccines; it has been more than 20 years since rich countries started using Thimerosal-free vaccines. TCVs and Thimerosal-free vaccines show dissimilar profiles of adverse effects. Thimerosal-free vaccines have shown a decrease in contact dermatitis, while TCVs showed a significant association with increased risk of tic disorders; in some circumstances, EtHg in combination with other neurotoxic substances negatively impacted neurobehavioral tests. In studies that explored vaccines and risk of tics, Thimerosal was a necessary factor. However, when the binary exposure to organic Hg forms (TCV-EtHg and fish-MeHg) was considered, effects on neurobehavioral tests were inconsistent. CONCLUSIONS (a) The indiscriminate use of pediatric-TCVs in less developed countries carries an unjustifiable and excessive EtHg exposure with an unnecessary risk of neurotoxicity to the developing brain; (b) measurable benefits (of Thimerosal-free) and measurable risks of tic disorders have been associated with the (Thimerosal-containing) type of vaccine;
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Affiliation(s)
- José G Dórea
- Professor Emeritus, Faculty of Health Sciences, Universidade de Brasília, 70919-970, Brasília, DF, Brazil.
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20
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Branco V, Caito S, Farina M, Teixeira da Rocha J, Aschner M, Carvalho C. Biomarkers of mercury toxicity: Past, present, and future trends. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2017; 20:119-154. [PMID: 28379072 PMCID: PMC6317349 DOI: 10.1080/10937404.2017.1289834] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Mercury (Hg) toxicity continues to represent a global health concern. Given that human populations are mostly exposed to low chronic levels of mercurial compounds (methylmercury through fish, mercury vapor from dental amalgams, and ethylmercury from vaccines), the need for more sensitive and refined tools to assess the effects and/or susceptibility to adverse metal-mediated health risks remains. Traditional biomarkers, such as hair or blood Hg levels, are practical and provide a reliable measure of exposure, but given intra-population variability, it is difficult to establish accurate cause-effect relationships. It is therefore important to identify and validate biomarkers that are predictive of early adverse effects prior to adverse health outcomes becoming irreversible. This review describes the predominant biomarkers used by toxicologists and epidemiologists to evaluate exposure, effect and susceptibility to Hg compounds, weighing on their advantages and disadvantages. Most importantly, and in light of recent findings on the molecular mechanisms underlying Hg-mediated toxicity, potential novel biomarkers that might be predictive of toxic effect are presented, and the applicability of these parameters in risk assessment is examined.
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Affiliation(s)
- Vasco Branco
- a Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia , Universidade de Lisboa , Lisboa , Portugal
| | - Sam Caito
- b Department of Molecular Pharmacology , Albert Einstein College of Medicine , Bronx , New York , USA
| | - Marcelo Farina
- c Departamento de Bioquímica, Centro de Ciências Biológicas , Universidade Federal de Santa Catarina , Florianópolis , Brazil
| | - João Teixeira da Rocha
- d Departamento Bioquímica e Biologia Molecular , Universidade Federal de Santa Maria , Santa Maria , RS , Brazil
| | - Michael Aschner
- b Department of Molecular Pharmacology , Albert Einstein College of Medicine , Bronx , New York , USA
| | - Cristina Carvalho
- a Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia , Universidade de Lisboa , Lisboa , Portugal
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Dórea JG. Low-dose Thimerosal in pediatric vaccines: Adverse effects in perspective. ENVIRONMENTAL RESEARCH 2017; 152:280-293. [PMID: 27816865 DOI: 10.1016/j.envres.2016.10.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 10/26/2016] [Accepted: 10/27/2016] [Indexed: 06/06/2023]
Abstract
Vaccines are prophylactics used as the first line of intervention to prevent, control and eradicate infectious diseases. Young children (before the age of six months) are the demographic group most exposed to recommended/mandatory vaccines preserved with Thimerosal and its metabolite ethylmercury (EtHg). Particularly in the less-developed countries, newborns, neonates, and young children are exposed to EtHg because it is still in several of their pediatric vaccines and mothers are often immunized with Thimerosal-containing vaccines (TCVs) during pregnancy. While the immunogenic component of the product has undergone more rigorous testing, Thimerosal, known to have neurotoxic effects even at low doses, has not been scrutinized for the limit of tolerance alone or in combination with adjuvant-Al during immaturity or developmental periods (pregnant women, newborns, infants, and young children). Scientific evidence has shown the potential hazards of Thimerosal in experiments that modeled vaccine-EtHg concentrations. Observational population studies have revealed uncertainties related to neurological effects. However, consistently, they showed a link of EtHg with risk of certain neurodevelopment disorders, such as tic disorder, while clearly revealing the benefits of removing Thimerosal from children's vaccines (associated with immunological reactions) in developed countries. So far, only rich countries have benefited from withdrawing the risk of exposing young children to EtHg. Regarding Thimerosal administered to the very young, we have sufficient studies that characterize a state of uncertainty: the collective evidence strongly suggests that Thimerosal exposure is associated with adverse neurodevelopmental outcomes. It is claimed that the continued use of Thimerosal in the less-developed countries is due to the cost to change to another preservative, such as 2-phenoxyethanol. However, the estimated cost increase per child in the first year of life is lower than estimated lifetime cost of caring for a child with a neurodevelopmental disorder, such tic disorder. The evidence indicates that Thimerosal-free vaccine options should be made available in developing countries.
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Affiliation(s)
- José G Dórea
- Professor Emeritus, Faculty of Health Sciences, Universidade de Brasilia, 70919-970 Brasilia, DF, Brazil.
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22
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Geier DA, Kern JK, Homme KG, Geier MR. Abnormal Brain Connectivity Spectrum Disorders Following Thimerosal Administration: A Prospective Longitudinal Case-Control Assessment of Medical Records in the Vaccine Safety Datalink. Dose Response 2017; 15:1559325817690849. [PMID: 28539852 PMCID: PMC5433557 DOI: 10.1177/1559325817690849] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Autism spectrum disorder (ASD), tic disorder (TD), and hyperkinetic syndrome of childhood (attention deficit disorder [ADD]/attention deficit hyperactivity disorder [ADHD]) are disorders recently defined as abnormal connectivity spectrum disorders (ACSDs) because they show a similar pattern of abnormal brain connectivity. This study examines whether these disorders are associated with exposure to thimerosal, a mercury (Hg)-based preservative. METHODS A hypothesis testing case-control study evaluated the Vaccine Safety Datalink for the potential dose-dependent odds ratios (ORs) for diagnoses of ASD, TD, and ADD/ADHD compared to controls, following exposure to Hg from thimerosal-containing Haemophilus influenzae type b vaccines administrated within the first 15 months of life. Febrile seizures, cerebral degeneration, and unspecified disorders of metabolism, which are not biologically plausibly linked to thimerosal, were examined as control outcomes. RESULTS On a per 25 μg Hg basis, cases diagnosed with ASD (OR = 1.493), TD (OR = 1.428), or ADD/ADHD (OR = 1.503) were significantly (P < .001) more likely than controls to have received increased Hg exposure. Similar relationships were observed when separated by gender. Cases diagnosed with control outcomes were no more likely than controls to have received increased Hg exposure. CONCLUSION The results suggest that Hg exposure from thimerosal is significantly associated with the ACSDs of ASD, TD, and ADD/ADHD.
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Affiliation(s)
- David A. Geier
- Department of Research, The Institute of Chronic Illnesses, Inc, Silver Spring, MD, USA
- CoMeD, Inc, Silver Spring, MD, USA
| | - Janet K. Kern
- Department of Research, The Institute of Chronic Illnesses, Inc, Silver Spring, MD, USA
- CoMeD, Inc, Silver Spring, MD, USA
- CONEM US Autism Research Group, Allen, TX, USA
| | - Kristin G. Homme
- International Academy of Oral Medicine and Toxicology, ChampionsGate, FL, USA
| | - Mark R. Geier
- Department of Research, The Institute of Chronic Illnesses, Inc, Silver Spring, MD, USA
- CoMeD, Inc, Silver Spring, MD, USA
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23
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Yin L, Yu K, Lin S, Song X, Yu X. Associations of blood mercury, inorganic mercury, methyl mercury and bisphenol A with dental surface restorations in the U.S. population, NHANES 2003-2004 and 2010-2012. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 134P1:213-225. [PMID: 27639196 DOI: 10.1016/j.ecoenv.2016.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 08/30/2016] [Accepted: 09/01/2016] [Indexed: 05/09/2023]
Abstract
The potential adverse health effects of mercury from amalgam and bisphenol A (BPA) from composite resin have been significant concerns. It is unclear whether dental restorative materials significantly contribute to mercury or BPA levels. The purpose of this study is to use NHANES data including 14,703 subjects (2003-2004: n=7514; 2011-2012: n=7189) to examine the association between Dental Surface Restorations (DSR) and blood total mercury (THg), inorganic mercury (IHg), methyl mercury (MeHg) and urinary BPA through the stratification of covariates and multivariate analysis. Subjects were divided into three groups based on the number of dental surface restorations (DSRs, 0, 1-8, >8). Blood THg and IHg in 2003-2004 were significantly higher in the subjects with DSR (geometric mean of 0.48, 0.69 and 1.17μg/l for THg; 0.32, 0.33 and 0.39μg/l for IHg with DSR 0, 1-8 and >8). Similarly, increases of THg, IHg and MeHg were also observed in 2013-2014 (geometric mean of 0.51, 0.69 and 0.99μg/l for THg; 0.40, 0.49 and 0.66μg/l for MeHg; 0.20, 0.22 and 0.29μg/l for IHg with DSR 0, 1-8 and >8). Linear regression model analysis revealed blood THg and IHg in 2003-2004 and THg, IHg and MeHg in 2011-2012 were quantitatively associated with the number of DSRs. A dramatic decrease in urinary BPA from 2003 to 2004-2011-2012 was observed, but no significant increase with DSRs in either period of study. In conclusion, significant increases in blood THg, IHg, and MeHg in the subjects with DSRs are confirmed in a nationally representative population, a critical step in assessing the potential risk of adverse effects from dental restorative materials, but no association between dental fillings and urinary BPA was found.
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Affiliation(s)
- Lei Yin
- Department of Environmental Health Science, University of Georgia, Athens, GA, USA
| | - Kevin Yu
- Department of Environmental Health Science, University of Georgia, Athens, GA, USA
| | - Simon Lin
- The Center for Pediatric Dentistry, University of Washington, USA
| | - Xiao Song
- Department of Epidemiology and Biostatistics, University of Georgia, Athens, GA, USA
| | - Xiaozhong Yu
- Department of Environmental Health Science, University of Georgia, Athens, GA, USA.
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Marques RC, Abreu L, Bernardi JVE, Dórea JG. Neurodevelopment of Amazonian children exposed to ethylmercury (from Thimerosal in vaccines) and methylmercury (from fish). ENVIRONMENTAL RESEARCH 2016; 149:259-265. [PMID: 26774584 DOI: 10.1016/j.envres.2015.12.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 12/15/2015] [Accepted: 12/19/2015] [Indexed: 05/24/2023]
Abstract
Few studies have addressed co-occurring methylmercury (MeHg) from maternal origin and ethylmercury (EtHg) from Thimerosal-containing vaccines (TCVs) during infant's neurodevelopment. We studied children (n=1139) from the Western Amazon based on combined (low, intermediate, and high) exposure to chronic MeHg from fish consumption and acute TCV- EtHg. Neurodevelopment outcomes were age of walking and age of talking, and the Bayley Scale of Infant Development (BSID). The Mental Developmental Index (MDI) and Psychomotor Developmental Index (PDI) were measured at six and 24 months of age. Median hair-Hg (HHg) at birth was 6.4µgg(-1) in mothers, and 1.94µgg(-1) in newborns; total (pregnancy and infancy) EtHg exposure ranged from 0 to 187.5µg. The combined (MeHg+EtHg) exposure showed significant differences for MDI but not for PDI; however, there was a significant decrease in both MDI and PDI scores at 24 months. The increase in BSID delays (scores <80) between six and 24 months was not discernible with regards to EtHg or MeHg exposure. We found a statistically significant increase in neurodevelopmental (BSID) delays related to the combined exposure to Hg (MeHg>EtHg). Neurodevelopment delays due to low-doses of organic mercury (albeit undiscernible) are not predictable but can be avoided by choosing low-Hg fish and providing Thimerosal-free vaccines.
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Affiliation(s)
- Rejane C Marques
- Universidade Federal do Rio de Janeiro, Rio de Janeiro CEP 27930-560, RJ, Brazil.
| | | | | | - José G Dórea
- Universidade de Brasília, Brasília, 7 0919-970, DF, Brazil.
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Souza-Araujo J, Giarrizzo T, Lima MO, Souza MBG. Mercury and methyl mercury in fishes from Bacajá River (Brazilian Amazon): evidence for bioaccumulation and biomagnification. JOURNAL OF FISH BIOLOGY 2016; 89:249-263. [PMID: 27241551 DOI: 10.1111/jfb.13027] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 04/18/2016] [Indexed: 06/05/2023]
Abstract
This study assessed total mercury (THg) and methyl mercury (MeHg) concentrations, bioaccumulation and biomagnification of THg through the food web in fishes consumed by indigenous communities of Bacajá River, the largest tributary of the right bank of Xingu River. In total, 496 fish (22 species) were sampled. Nine species had THg concentrations above the limit recommended by the World Health Organisation (0·5 µg g(-1) wet mass), and one exceeded the recommended level for Hg in predatory fishes by Brazilian law (1·0 µg g(-1) ). The average concentration of THg increased significantly with trophic guild (herbivorous to piscivorous) and trophic level, with higher accumulation in fishes with greater total length. Ninety-six per cent of all mercury was methylated. These results suggest that feeding habits determine THg concentrations in fishes and that Hg elimination rate is slow during growth, which allows greater accumulation. These findings show that fishes in the Bacajá River contain high concentrations of THg and MeHg.
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Affiliation(s)
- J Souza-Araujo
- Aquatic Ecology Group, Federal University of Pará, Avenida Perimetral 2651, Terra Firme, 66040170, Belém, PA, Brazil
| | - T Giarrizzo
- Aquatic Ecology Group, Federal University of Pará, Avenida Perimetral 2651, Terra Firme, 66040170, Belém, PA, Brazil
| | - M O Lima
- Evandro Chagas Institute, Environment Section, Rodovia BR-316, km 7, S/N, Levilândia, 67030000, Ananindeua, PA, Brazil
| | - M B G Souza
- Tractebel Engineering-LEME Engineering, Avenida dos Andradas 3000, Santa Efigênia, 30260070, Belo Horizonte, MG, Brazil
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Abstract
CONTEXT Environmental mercury in the Amazon mostly originates from geochemical sources with some from artisanal gold mining (AGM). Geochemical-originated methylmercury (MeHg) reaches the aquatic food chain, ending up in fish. Inorganic Hg used in AGM is responsible for localised environmental contamination and occupational exposure of adults. In addition to this, iatrogenic ethylmercury (EtHg) derived from Thimerosal-containing vaccines (TCVs) exposes immunised infants. OBJECTIVE To understand Hg exposure in the Amazon in relation to environmental fish-MeHg exposure, occupational AGM activities and low-doses of TCV-EtHg. METHODS Medline and Thomson-Reuter Web of Science were searched to retrieve and select papers addressing Hg exposure and human health. RESULTS AND CONCLUSION Environmental-Hg studies addressed health effects associated with birth weight, infant linear growth and neurodevelopment, while, in adults, environmental and occupational studies addressed immune and neurological issues. No widespread clinical toxicity was reported due to fish-MeHg. However, mixed results associated with Hg exposure can be found. Reducing children's exposure to EtHg is possible using Thimerosal-free vaccines, but it is difficult to interfere with fish consumption without consequences to riverine subsistence populations. Policies to diminish Hg exposure should focus on controlling and/or curbing widespread use of Hg (in gold amalgamation) and promotion of Thimerosal-free vaccines for pregnant women and young children.
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Affiliation(s)
- José G Dórea
- a Universidade de Brasília , Brasília , DF , Brasil
| | - Rejane C Marques
- b Universidade Federal do Rio de Janeiro , Rio de Janeiro , RJ, Brasil
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Milhomem Filho EO, Oliveira CSBD, Silveira LCDL, Cruz TM, Souza GDS, Costa Junior JMF, Pinheiro MDCN. The intake of fish and the mercury concentration of fishing families at the city of Imperatriz (MA), Brazil. REVISTA BRASILEIRA DE EPIDEMIOLOGIA 2016; 19:14-25. [PMID: 27167645 DOI: 10.1590/1980-5497201600010002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 12/14/2015] [Indexed: 11/21/2022] Open
Abstract
INTRODUCTION Significant levels of mercury exposure associated with fish intake have been demonstrated in riverine populations living in areas of mineral exploration as the basin of Tapajós and Madeira. In the Tocantins region, although few studies, there is no evidence of human exposure through food. OBJECTIVE To assess the levels of exposure to mercury in resident fishermen families in the riverside area of the middle Tocantins and to quantify the levels in fish consumed by these families. METHODS We conducted a cross sectional study involving families of Beira Rio community fishermen, located on the Tocantins riverbanks in the city of Imperatriz, Maranhão. Brazil. Data were collected from socio demographic and food profile, as well as samples of fish and hair, which were analyzed by atomic absorption spectrophotometry. RESULTS The socio demographic profile of families studied was common to the local population located in other basins. The food profile did not run the default rule, with the fish being the primary dietary protein source. The species of piscivorous and zooplancton habits had the highest mercury concentrations, and the mean values were 0.2775 µg/g in fish dog and 0.1360 µg/g in mapará. Among the 25 families evaluated, the lowest average concentration of family was 0.186 ± 0.043 µg/g and the higher was 5.477 ± 2.896 µg/g. CONCLUSION Fishing families have low mercury exposure levels in the same order of magnitude, probably because of the food consumption of fish, including piscivorous species, which were found to be below the safe upper limit for human consumption established by Brazilian standards. This serves as a reference for other studies.
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Mohamed FEB, Zaky EA, El-Sayed AB, Elhossieny RM, Zahra SS, Salah Eldin W, Youssef WY, Khaled RA, Youssef AM. Assessment of Hair Aluminum, Lead, and Mercury in a Sample of Autistic Egyptian Children: Environmental Risk Factors of Heavy Metals in Autism. Behav Neurol 2015; 2015:545674. [PMID: 26508811 PMCID: PMC4609793 DOI: 10.1155/2015/545674] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 08/24/2015] [Accepted: 09/02/2015] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND AND AIMS The etiological factors involved in the etiology of autism remain elusive and controversial, but both genetic and environmental factors have been implicated. The aim of this study was to assess the levels and possible environmental risk factors and sources of exposure to mercury, lead, and aluminum in children with autism spectrum disorder (ASD) as compared to their matched controls. METHODS One hundred ASD children were studied in comparison to 100 controls. All participants were subjected to clinical evaluation and measurement of mercury, lead, and aluminum through hair analysis which reflects past exposure. RESULTS The mean Levels of mercury, lead, and aluminum in hair of the autistic patients were significantly higher than controls. Mercury, lead, and aluminum levels were positively correlated with maternal fish consumptions, living nearby gasoline stations, and the usage of aluminum pans, respectively. CONCLUSION Levels of mercury, lead, and aluminum in the hair of autistic children are higher than controls. Environmental exposure to these toxic heavy metals, at key times in development, may play a causal role in autism.
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Affiliation(s)
| | - Eman Ahmed Zaky
- Pediatrics Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | | | | | - Sally Soliman Zahra
- Pediatrics Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt
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29
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Marques RC, Bernardi JVE, Abreu L, Dórea JG. Neurodevelopment outcomes in children exposed to organic mercury from multiple sources in a tin-ore mine environment in Brazil. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2015; 68:432-441. [PMID: 25425160 DOI: 10.1007/s00244-014-0103-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 11/03/2014] [Indexed: 06/04/2023]
Abstract
Methylmercury (from fresh-water fish) and ethylmercury [from thimerosal-containing vaccines (TCVs)] are the most prevalent source of neurotoxic exposure during early life in families consuming fish and using these vaccines. But children living in Amazonian mining environments are exposed to additional toxic metals in waste materials. We studied mercury (Hg) exposure and neurodevelopment in 294 children (105 boys and 189 girls) from Bom Futuro (Rondonia, Brazil), the epicenter of a tin-ore open-pit mine. Hair-Hg (HHg) concentrations and total ethylmercury (from TCVs) were taken from infants and respective mothers during pregnancy. We used bivariate analysis to determine the effect of sex and linear mixed models to assess the association of prenatal and postnatal organic Hg exposures with children's Bayley Scales of Infant Development (BSID) as psychomotor developmental index and mental developmental index (MDI) at 6 and 24 months of age as well as milestones achievements (age of walking and age of talking). Significant differences between boys and girls were observed for both MDI score (p = 0.0073) and MDI score (p = 0.0288) at 6 months but not at 24 months. Regression analysis showed that only in boys was there a significant interaction between MDI score with family income (β = 0.288, p = 0.018) and with birth weight (β = -0.216, p = 0.036) at 6 months; at 24 months, however, only boys showed a significant association of both MDI score (β = -0.222, p = 0.045) and MDI score (β = -0.222, p = 0.045) with neonatal HHg. In boys, age of walking was associated with HHg (β = 0.188, p = 0.019) and breastfeeding (β = -0.282, p = 0.000), whereas for girls, age of walking was only associated with breastfeeding (β = -0.275, p = 0.001). In this mining environment, with only a weak association for prenatal Hg exposure, there was a significant sex difference in neurodevelopment, with boys showing more sensitivity related to BSID delays.
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Affiliation(s)
- Rejane C Marques
- Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 27930-560, Brazil,
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30
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Geier DA, King PG, Hooker BS, Dórea JG, Kern JK, Sykes LK, Geier MR. Thimerosal: Clinical, epidemiologic and biochemical studies. Clin Chim Acta 2015; 444:212-20. [DOI: 10.1016/j.cca.2015.02.030] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 02/06/2015] [Accepted: 02/14/2015] [Indexed: 10/24/2022]
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Dórea JG. Exposure to mercury and aluminum in early life: developmental vulnerability as a modifying factor in neurologic and immunologic effects. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:1295-313. [PMID: 25625408 PMCID: PMC4344667 DOI: 10.3390/ijerph120201295] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 01/20/2015] [Indexed: 01/15/2023]
Abstract
Currently, ethylmercury (EtHg) and adjuvant-Al are the dominating interventional exposures encountered by fetuses, newborns, and infants due to immunization with Thimerosal-containing vaccines (TCVs). Despite their long use as active agents of medicines and fungicides, the safety levels of these substances have never been determined, either for animals or for adult humans—much less for fetuses, newborns, infants, and children. I reviewed the literature for papers reporting on outcomes associated with (a) multiple exposures and metabolism of EtHg and Al during early life; (b) physiological and metabolic characteristics of newborns, neonates, and infants relevant to xenobiotic exposure and effects; (c) neurobehavioral, immunological, and inflammatory reactions to Thimerosal and Al-adjuvants resulting from TCV exposure in infancy. Immunological and neurobehavioral effects of Thimerosal-EtHg and Al-adjuvants are not extraordinary; rather, these effects are easily detected in high and low income countries, with co-exposure to methylmercury (MeHg) or other neurotoxicants. Rigorous and replicable studies (in different animal species) have shown evidence of EtHg and Al toxicities. More research attention has been given to EtHg and findings have showed a solid link with neurotoxic effects in humans; however, the potential synergic effect of both toxic agents has not been properly studied. Therefore, early life exposure to both EtHg and Al deserves due consideration.
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Affiliation(s)
- José G Dórea
- Department of Nutrition, Faculty of Health Sciences, Universidade de Brasilia, 70919-970 DF Brasilia, Brazil.
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32
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Geier DA, Kern JK, Hooker BS, King PG, Sykes LK, Geier MR. Thimerosal-containing hepatitis B vaccination and the risk for diagnosed specific delays in development in the United States: a case-control study in the vaccine safety datalink. NORTH AMERICAN JOURNAL OF MEDICAL SCIENCES 2014; 6:519-31. [PMID: 25489565 PMCID: PMC4215490 DOI: 10.4103/1947-2714.143284] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background: Within the first 3 years of life, the brain develops rapidly. Its development is characterized by critical developmental periods for speech, vision, hearing, language, balance, etc.; and alteration in any of the processes occurring in those critical periods can lead to specific delays in development. Aims: The present study evaluated the potential toxic effects of organic-mercury exposure from Thimerosal (49.55% mercury by weight) in childhood vaccines and its hypothesized possible relationship with specific delays in development. Materials and Methods: A hypothesis testing case-control study was undertaken to evaluate the relationship between exposure to Thimerosal-containing hepatitis B vaccines administered at specific intervals in the first 6 months among cases diagnosed with specific delays in development and controls born between 1991-2000, utilizing data in the Vaccine Safety Datalink database. Results: Cases were significantly more likely than controls to have received increased organic-mercury from Thimerosal-containing hepatitis B vaccine administered in the first, second, and sixth month of life. Conclusion: Though routine childhood vaccination may be an important public health tool to reduce the morbidity and mortality associated with infectious diseases, the present study supports an association between increasing organic-mercury exposure from Thimerosal-containing childhood vaccines and the subsequent risk of specific delays in development among males and females.
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Affiliation(s)
- David A Geier
- Institute of Chronic Illnesses, Inc, Silver Spring, Maryland, USA
| | - Janet K Kern
- Institute of Chronic Illnesses, Inc, Silver Spring, Maryland, USA ; Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Brian S Hooker
- Biology Department, Simpson University, Redding, California, USA
| | | | | | - Mark R Geier
- Institute of Chronic Illnesses, Inc, Silver Spring, Maryland, USA
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Gibb H, O'Leary KG. Mercury exposure and health impacts among individuals in the artisanal and small-scale gold mining community: a comprehensive review. ENVIRONMENTAL HEALTH PERSPECTIVES 2014; 122:667-72. [PMID: 24682486 PMCID: PMC4080518 DOI: 10.1289/ehp.1307864] [Citation(s) in RCA: 210] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 03/26/2014] [Indexed: 05/20/2023]
Abstract
BACKGROUND Mercury (Hg) is used in gold mining to extract gold from ore by forming "amalgam"-a mixture composed of approximately equal parts mercury and gold. Approximately 15 million people, including approximately 3 million women and children, participate in artisanal small-scale gold mining (ASGM) in developing countries. Thirty-seven percent of global air emissions of Hg are produced by ASGM. The recently adopted Minamata Convention calls for nations to gather health data, train health-care workers, and raise awareness in regard to ASGM activity. OBJECTIVE The purpose of our review was to evaluate the current literature regarding the health effects of Hg among those working and/or living in or near ASGM communities. METHODS We searched PubMed, ScienceDirect, and Google Scholar for studies relating to health effects and biomarkers of Hg exposure in ASGM communities. Articles published from 1990 through December 2012 were evaluated for relevance. DISCUSSION Studies reporting health assessments, kidney dysfunction, neurological disorders and symptoms, and immunotoxicity/autoimmune dysfunction in individuals living in or near an ASGM community were identified. More than 60 studies that measured biomarkers of Hg exposure in individuals living in or near ASGM communities were also identified. These studies, conducted in 19 different countries in South America, Asia, and Africa, demonstrated that hair and urine concentrations are well above World Health Organization health guidance values in ASGM communities. CONCLUSIONS ASGM workers and their families are exposed to Hg vapor, and workers, workers' families, and residents of nearby and downstream communities are consuming fish heavily contaminated with methylmercury.
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Affiliation(s)
- Herman Gibb
- Tetra Tech Sciences, Arlington, Virginia, USA
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34
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Methodological issues and evidence of malfeasance in research purporting to show thimerosal in vaccines is safe. BIOMED RESEARCH INTERNATIONAL 2014; 2014:247218. [PMID: 24995277 PMCID: PMC4065774 DOI: 10.1155/2014/247218] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 05/12/2014] [Indexed: 11/21/2022]
Abstract
There are over 165 studies that have focused on Thimerosal, an organic-mercury (Hg) based compound, used as a preservative in many childhood vaccines, and found it to be harmful. Of these, 16 were conducted to specifically examine the effects of Thimerosal on human infants or children with reported outcomes of death; acrodynia; poisoning; allergic reaction; malformations; auto-immune reaction; Well's syndrome; developmental delay; and neurodevelopmental disorders, including tics, speech delay, language delay, attention deficit disorder, and autism. In contrast, the United States Centers for Disease Control and Prevention states that Thimerosal is safe and there is “no relationship between [T]himerosal[-]containing vaccines and autism rates in children.” This is puzzling because, in a study conducted directly by CDC epidemiologists, a 7.6-fold increased risk of autism from exposure to Thimerosal during infancy was found. The CDC's current stance that Thimerosal is safe and that there is no relationship between Thimerosal and autism is based on six specific published epidemiological studies coauthored and sponsored by the CDC. The purpose of this review is to examine these six publications and analyze possible reasons why their published outcomes are so different from the results of investigations by multiple independent research groups over the past 75+ years.
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Sheehan MC, Burke TA, Navas-Acien A, Breysse PN, McGready J, Fox MA. Global methylmercury exposure from seafood consumption and risk of developmental neurotoxicity: a systematic review. Bull World Health Organ 2014; 92:254-269F. [PMID: 24700993 PMCID: PMC3967569 DOI: 10.2471/blt.12.116152] [Citation(s) in RCA: 169] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 10/15/2013] [Accepted: 11/12/2013] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE To examine biomarkers of methylmercury (MeHg) intake in women and infants from seafood-consuming populations globally and characterize the comparative risk of fetal developmental neurotoxicity. METHODS A search was conducted of the published literature reporting total mercury (Hg) in hair and blood in women and infants. These biomarkers are validated proxy measures of MeHg, a neurotoxin found primarily in seafood. Average and high-end biomarkers were extracted, stratified by seafood consumption context, and pooled by category. Medians for average and high-end pooled distributions were compared with the reference level established by a joint expert committee of the Food and Agriculture Organization (FAO) and the World Health Organization (WHO). FINDINGS Selection criteria were met by 164 studies of women and infants from 43 countries. Pooled average biomarkers suggest an intake of MeHg several times over the FAO/WHO reference in fish-consuming riparians living near small-scale gold mining and well over the reference in consumers of marine mammals in Arctic regions. In coastal regions of south-eastern Asia, the western Pacific and the Mediterranean, average biomarkers approach the reference. Although the two former groups have a higher risk of neurotoxicity than the latter, coastal regions are home to the largest number at risk. High-end biomarkers across all categories indicate MeHg intake is in excess of the reference value. CONCLUSION There is a need for policies to reduce Hg exposure among women and infants and for surveillance in high-risk populations, the majority of which live in low-and middle-income countries.
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Affiliation(s)
- Mary C Sheehan
- Risk Sciences and Public Policy Institute, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, United States of America (USA)
| | - Thomas A Burke
- Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
| | - Ana Navas-Acien
- Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
| | - Patrick N Breysse
- Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
| | - John McGready
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
| | - Mary A Fox
- Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
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36
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Dórea JG, Marques RC, Abreu L. Milestone achievement and neurodevelopment of rural Amazonian toddlers (12 to 24 months) with different methylmercury and ethylmercury exposure. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2014; 77:1-13. [PMID: 24555642 DOI: 10.1080/15287394.2014.861335] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Neurological outcomes (Gesell development schedules [GDS]), age of walking, and age of talking were studied in 299 toddlers (12 to 24 mo) in relation to environmental (fish consumption and tin mining) exposure. Exposure to fish methylmercury (MeHg) consumption and iatrogenic ethylmercury (EtHg) in Thimerosal-containing vaccines (TCV) was quantified in toddlers from two rural villages (n = 91, Itapuã; n = 218, Bom Futuro) respectively populated by fishers and cassiterite miners. Median total hair Hg (HHg) concentrations of infants from Itapuã (3.5 μg/g) were significantly higher than those of infants from Bom Futuro (2.2 μg/g). Median EtHg exposure from TCV was also significantly higher in toddlers from Itapuã (137.5 μg) than in those from Bom Futuro (112.5 μg). There were no significant differences between groups for any of the Gesell schedules; however, there were proportionally more compromised toddlers (GDS < 70) in Itapuã than Bom Futuro. Median age of talking was not statistically different but median age of walking was significantly higher in Bom Futuro. In toddlers from both villages, of fishers and miners, HHg concentrations were significantly correlated with family fish consumption. A logistic regression model was applied to all infants after classification into two groups: above or below the median Gesell schedules. Overall, there was no distinctive pattern of neurodevelopment associated with either HHg or EtHg exposure; however, nutritional status was significantly associated with GDS. In conclusion, milestone achievement was delayed in toddlers from tin-ore mining communities. Despite significantly higher exposure to both forms of organic Hg (MeHg from maternal fish consumption, and EtHg from TCV) in toddlers from the fishing village, significant differences were seen only among the proportions of most severely affected toddlers (GDS < 70).
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Affiliation(s)
- José G Dórea
- a Department of Nutrition , Universidade de Brasília , Brasília , Brazil
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Kern JK, Haley BE, Geier DA, Sykes LK, King PG, Geier MR. Thimerosal exposure and the role of sulfation chemistry and thiol availability in autism. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:3771-800. [PMID: 23965928 PMCID: PMC3774468 DOI: 10.3390/ijerph10083771] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/10/2013] [Accepted: 07/11/2013] [Indexed: 01/22/2023]
Abstract
Autism spectrum disorder (ASD) is a neurological disorder in which a significant number of the children experience a developmental regression characterized by a loss of previously acquired skills and abilities. Typically reported are losses of verbal, nonverbal, and social abilities. Several recent studies suggest that children diagnosed with an ASD have abnormal sulfation chemistry, limited thiol availability, and decreased glutathione (GSH) reserve capacity, resulting in a compromised oxidation/reduction (redox) and detoxification capacity. Research indicates that the availability of thiols, particularly GSH, can influence the effects of thimerosal (TM) and other mercury (Hg) compounds. TM is an organomercurial compound (49.55% Hg by weight) that has been, and continues to be, used as a preservative in many childhood vaccines, particularly in developing countries. Thiol-modulating mechanisms affecting the cytotoxicity of TM have been identified. Importantly, the emergence of ASD symptoms post-6 months of age temporally follows the administration of many childhood vaccines. The purpose of the present critical review is provide mechanistic insight regarding how limited thiol availability, abnormal sulfation chemistry, and decreased GSH reserve capacity in children with an ASD could make them more susceptible to the toxic effects of TM routinely administered as part of mandated childhood immunization schedules.
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Affiliation(s)
- Janet K. Kern
- Institute of Chronic Illnesses, Inc., Silver Spring, MD 20905, USA; E-Mails: (D.A.G.); (M.R.G.)
| | - Boyd E. Haley
- Department of Chemistry, University of Kentucky, Lexington, KY 40506, USA; E-Mail:
| | - David A. Geier
- Institute of Chronic Illnesses, Inc., Silver Spring, MD 20905, USA; E-Mails: (D.A.G.); (M.R.G.)
| | - Lisa K. Sykes
- CoMeD, Inc., Silver Spring, MD 20905, USA; E-Mails: (L.K.S.); (P.G.K.)
| | - Paul G. King
- CoMeD, Inc., Silver Spring, MD 20905, USA; E-Mails: (L.K.S.); (P.G.K.)
| | - Mark R. Geier
- Institute of Chronic Illnesses, Inc., Silver Spring, MD 20905, USA; E-Mails: (D.A.G.); (M.R.G.)
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Rudgalvyte M, VanDuyn N, Aarnio V, Heikkinen L, Peltonen J, Lakso M, Nass R, Wong G. Methylmercury exposure increases lipocalin related (lpr) and decreases activated in blocked unfolded protein response (abu) genes and specific miRNAs in Caenorhabditis elegans. Toxicol Lett 2013; 222:189-96. [PMID: 23872261 DOI: 10.1016/j.toxlet.2013.07.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/10/2013] [Accepted: 07/10/2013] [Indexed: 01/15/2023]
Abstract
Methylmercury (MeHg) is a persistent environmental and dietary contaminant that causes serious adverse developmental and physiologic effects at multiple cellular levels. In order to understand more fully the consequences of MeHg exposure at the molecular level, we profiled gene and miRNA transcripts from the model organism Caenorhabditis elegans. Animals were exposed to MeHg (10 μM) from embryo to larval 4 (L4) stage and RNAs were isolated. RNA-seq analysis on the Illumina platform revealed 541 genes up- and 261 genes down-regulated at a cutoff of 2-fold change and false discovery rate-corrected significance q < 0.05. Among the up-regulated genes were those previously shown to increase under oxidative stress conditions including hsp-16.11 (2.5-fold), gst-35 (10.1-fold), and fmo-2 (58.5-fold). In addition, we observed up-regulation of 6 out of 7 lipocalin related (lpr) family genes and down regulation of 7 out of 15 activated in blocked unfolded protein response (abu) genes. Gene Ontology enrichment analysis highlighted the effect of genes related to development and organism growth. miRNA-seq analysis revealed 6-8 fold down regulation of mir-37-3p, mir-41-5p, mir-70-3p, and mir-75-3p. Our results demonstrate the effects of MeHg on specific transcripts encoding proteins in oxidative stress responses and in ER stress pathways. Pending confirmation of these transcript changes at protein levels, their association and dissociation characteristics with interaction partners, and integration of these signals, these findings indicate broad and dynamic mechanisms by which MeHg exerts its harmful effects.
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Affiliation(s)
- Martina Rudgalvyte
- A. I. Virtanen Institute for Molecular Sciences, Department of Neurobiology, University of Eastern Finland, Kuopio, Finland.
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Vaccine adverse events reported during the first ten years (1998-2008) after introduction in the state of Rondonia, Brazil. BIOMED RESEARCH INTERNATIONAL 2013; 2013:853083. [PMID: 23509790 PMCID: PMC3586457 DOI: 10.1155/2013/853083] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 01/07/2013] [Accepted: 01/11/2013] [Indexed: 02/01/2023]
Abstract
Despite good safety records, vaccines given to young children can cause adverse events. We investigated the reported adverse events following immunization (AEFI) of vaccines given to children of less than seven years of age during the first ten years (1998 to 2008) in the state of Rondonia, Brazil. We worked with the events related to BCG (Bacillus Calmett-Guérin), HB (hepatitis B), DTwP/Hib (diphtheria-tetanus-pertussis+Hemophillus influenza b), DTP (diphtheria-tetanus-pertussis), MMR (mumps, measles, rubella), and YF (yellow fever) vaccines because they were part of the recommended scheme. The number of doses of vaccines given was 3,231,567 with an average of AEFI of 57.2/year during the studied period. DTwP/Hib was responsible for 298 (57.8%), DTP 114 (22.9%), HB 31 (6%), MMR 28 (5.4%), BCG 24 (4.7%), and YF 20 (3.9%) of the reported AEFI. The combination of the AEFI for DTwP/Hib vaccines showed the highest number of systemic (61.4%) and local events (33.8%). Young children (≤1-year old) were more susceptible to AEFI occurring in the 6 hours (54.2%) following vaccine uptake. This study suggests significant differences in reactogenicity of vaccines and that despite limitations of the AEFI Brazilian registry system we cannot ignore underreporting and should use the system to expand our understanding of adverse events and effects.
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Dórea JG, Farina M, Rocha JBT. Toxicity of ethylmercury (and Thimerosal): a comparison with methylmercury. J Appl Toxicol 2013; 33:700-11. [PMID: 23401210 DOI: 10.1002/jat.2855] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 12/10/2012] [Accepted: 12/11/2012] [Indexed: 12/18/2022]
Abstract
Ethylmercury (etHg) is derived from the metabolism of thimerosal (o-carboxyphenyl-thio-ethyl-sodium salt), which is the most widely used form of organic mercury. Because of its application as a vaccine preservative, almost every human and animal (domestic and farmed) that has been immunized with thimerosal-containing vaccines has been exposed to etHg. Although methylmercury (meHg) is considered a hazardous substance that is to be avoided even at small levels when consumed in foods such as seafood and rice (in Asia), the World Health Organization considers small doses of thimerosal safe regardless of multiple/repetitive exposures to vaccines that are predominantly taken during pregnancy or infancy. We have reviewed in vitro and in vivo studies that compare the toxicological parameters among etHg and other forms of mercury (predominantly meHg) to assess their relative toxicities and potential to cause cumulative insults. In vitro studies comparing etHg with meHg demonstrate equivalent measured outcomes for cardiovascular, neural and immune cells. However, under in vivo conditions, evidence indicates a distinct toxicokinetic profile between meHg and etHg, favoring a shorter blood half-life, attendant compartment distribution and the elimination of etHg compared with meHg. EtHg's toxicity profile is different from that of meHg, leading to different exposure and toxicity risks. Therefore, in real-life scenarios, a simultaneous exposure to both etHg and meHg might result in enhanced neurotoxic effects in developing mammals. However, our knowledge on this subject is still incomplete, and studies are required to address the predictability of the additive or synergic toxicological effects of etHg and meHg (or other neurotoxicants).
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Affiliation(s)
- José G Dórea
- Department of Nutrition, Faculty of Health Sciences, Universidade de Brasilia, 70919-970, Brasilia, DF, Brazil.
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Dórea JG. Re: "prenatal exposure to mercury and infant neurodevelopment in a multicenter cohort in Spain: study of potential modifiers". Am J Epidemiol 2012; 176:1194-5; author reply 1195-6. [PMID: 23161896 DOI: 10.1093/aje/kws386] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Dórea JG. Neurotoxic metal coexposures and neurodevelopment. ENVIRONMENTAL HEALTH PERSPECTIVES 2012; 120:A226; author reply A226-7. [PMID: 22659231 PMCID: PMC3385458 DOI: 10.1289/ehp.1205004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
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