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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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Bjørklund G, Crisponi G, Nurchi VM, Cappai R, Buha Djordjevic A, Aaseth J. A Review on Coordination Properties of Thiol-Containing Chelating Agents Towards Mercury, Cadmium, and Lead. Molecules 2019; 24:E3247. [PMID: 31489907 PMCID: PMC6767255 DOI: 10.3390/molecules24183247] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 08/26/2019] [Accepted: 08/31/2019] [Indexed: 11/17/2022] Open
Abstract
The present article reviews the clinical use of thiol-based metal chelators in intoxications and overexposure with mercury (Hg), cadmium (Cd), and lead (Pb). Currently, very few commercially available pharmaceuticals can successfully reduce or prevent the toxicity of these metals. The metal chelator meso-2,3-dimercaptosuccinic acid (DMSA) is considerably less toxic than the classical agent British anti-Lewisite (BAL, 2,3-dimercaptopropanol) and is the recommended agent in poisonings with Pb and organic Hg. Its toxicity is also lower than that of DMPS (dimercaptopropane sulfonate), although DMPS is the recommended agent in acute poisonings with Hg salts. It is suggested that intracellular Cd deposits and cerebral deposits of inorganic Hg, to some extent, can be mobilized by a combination of antidotes, but clinical experience with such combinations are lacking. Alpha-lipoic acid (α-LA) has been suggested for toxic metal detoxification but is not considered a drug of choice in clinical practice. The molecular mechanisms and chemical equilibria of complex formation of the chelators with the metal ions Hg2+, Cd2+, and Pb2+ are reviewed since insight into these reactions can provide a basis for further development of therapeutics.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine, N-8610 Mo i Rana, Norway.
| | - Guido Crisponi
- Cittadella Universitaria, University of Cagliari, 09042 Cagliari, Italy.
| | - Valeria Marina Nurchi
- Department of Life and Environmental Sciences, University of Cagliari, 09042 Cagliari, Italy.
| | - Rosita Cappai
- Department of Life and Environmental Sciences, University of Cagliari, 09042 Cagliari, Italy.
| | - Aleksandra Buha Djordjevic
- Department of Toxicology "Akademik Danilo Soldatović", Faculty of Pharmacy, University of Belgrade, 11000 Belgrade, Serbia.
| | - Jan Aaseth
- Research Department, Innlandet Hospital, N-2380 Brumunddal, Norway.
- Inland Norway University of Applied Sciences, N-2411 Elverum, Norway.
- IM Sechenov First Moscow State Medical University (Sechenov University), 119146 Moscow, Russia.
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Steckling N, Bose-O’Reilly S, Pinheiro P, Plass D, Shoko D, Drasch G, Bernaudat L, Siebert U, Hornberg C. The burden of chronic mercury intoxication in artisanal small-scale gold mining in Zimbabwe: data availability and preliminary estimates. Environ Health 2014; 13:111. [PMID: 25495641 PMCID: PMC4290131 DOI: 10.1186/1476-069x-13-111] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 12/04/2014] [Indexed: 05/24/2023]
Abstract
BACKGROUND Artisanal small-scale gold mining (ASGM) is a poverty-driven activity practiced in over 70 countries worldwide. Zimbabwe is amongst the top ten countries using large quantities of mercury to extract gold from ore. This analysis was performed to check data availability and derive a preliminary estimate of disability-adjusted life years (DALYs) due to mercury use in ASGM in Zimbabwe. METHODS Cases of chronic mercury intoxication were identified following an algorithm using mercury-related health effects and mercury in human specimens. The sample prevalence amongst miners and controls (surveyed by the United Nations Industrial Development Organization in 2004 and the University of Munich in 2006) was determined and extrapolated to the entire population of Zimbabwe. Further epidemiological and demographic data were taken from the literature and missing data modeled with DisMod II to quantify DALYs using the methods from the Global Burden of Disease (GBD) 2004 update published by the World Health Organization (WHO). While there was no disability weight (DW) available indicating the relative disease severity of chronic mercury intoxication, the DW of a comparable disease was assigned by following the criteria 1) chronic condition, 2) triggered by a substance, and 3) causing similar health symptoms. RESULTS Miners showed a sample prevalence of 72% while controls showed no cases of chronic mercury intoxication. Data availability is very limited why it was necessary to model data and make assumptions about the number of exposed population, the definition of chronic mercury intoxication, DW, and epidemiology. If these assumptions hold, the extrapolation would result in around 95,400 DALYs in Zimbabwe's total population in 2004. CONCLUSIONS This analysis provides a preliminary quantification of the mercury-related health burden from ASGM based on the limited data available. If the determined assumptions hold, chronic mercury intoxication is likely to have been one of the top 20 hazards for population health in Zimbabwe in 2004 when comparing with more than 130 categories of diseases and injuries quantified in the WHO's GBD 2004 update. Improving data quality would allow more accurate estimates. However, the results highlight the need to reduce a burden which could be entirely avoided.
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Affiliation(s)
- Nadine Steckling
- />Department Environment & Health, Bielefeld University, School of Public Health, Universitätsstraße 25, D-33615 Bielefeld, Germany
- />University Hospital Munich, Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, WHO Collaborating Centre for Occupational Health, Workgroup Paediatric Environmental Epidemiology, Ziemssenstr. 1, D-80336 Munich, Germany
- />UMIT - University for Health Sciences, Medical Informatics and Technology, Department of Public Health and Health Technology Assessment, Institute of Public Health, Medical Decision Making and Health Technology Assessment, Eduard Wallnoefer Center I, A-6060 Hall i.T., Austria
| | - Stephan Bose-O’Reilly
- />University Hospital Munich, Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, WHO Collaborating Centre for Occupational Health, Workgroup Paediatric Environmental Epidemiology, Ziemssenstr. 1, D-80336 Munich, Germany
- />UMIT - University for Health Sciences, Medical Informatics and Technology, Department of Public Health and Health Technology Assessment, Institute of Public Health, Medical Decision Making and Health Technology Assessment, Eduard Wallnoefer Center I, A-6060 Hall i.T., Austria
| | - Paulo Pinheiro
- />Bielefeld University, Faculty of Educational Sciences, Universitätsstraße 25, D-33615 Bielefeld, Germany
| | - Dietrich Plass
- />Federal Environment Agency, Section Exposure Assessment and Environmental Health Indicators, Corrensplatz 1, D-14195 Berlin, Germany
| | - Dennis Shoko
- />Tailjet Consultancy Services, 4 Tor Road, Vainona, Borrowdale, Harare Zimbabwe
| | - Gustav Drasch
- />Institute of Forensic Medicine, Department of Forensic Toxicology, University of Munich - LMU, Nussbaumstr. 26, D-80336 Munich, Germany
| | - Ludovic Bernaudat
- />United Nations Industrial Development Organization, Vienna International Centre, P.O. Box 300, A-1400 Vienna, Austria
| | - Uwe Siebert
- />UMIT - University for Health Sciences, Medical Informatics and Technology, Department of Public Health and Health Technology Assessment, Institute of Public Health, Medical Decision Making and Health Technology Assessment, Eduard Wallnoefer Center I, A-6060 Hall i.T., Austria
- />Harvard Medical School, Massachusetts General Hospital, Institute for Technology Assessment and Department of Radiology, Boston, USA
- />Harvard School of Public Health, Department of Health Policy and Management, Center for Health Decision Science, Boston, USA
| | - Claudia Hornberg
- />Department Environment & Health, Bielefeld University, School of Public Health, Universitätsstraße 25, D-33615 Bielefeld, Germany
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