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Moksnes MR, Hansen AF, Wolford BN, Thomas LF, Rasheed H, Simić A, Bhatta L, Brantsæter AL, Surakka I, Zhou W, Magnus P, Njølstad PR, Andreassen OA, Syversen T, Zheng J, Fritsche LG, Evans DM, Warrington NM, Nøst TH, Åsvold BO, Flaten TP, Willer CJ, Hveem K, Brumpton BM. A genome-wide association study provides insights into the genetic etiology of 57 essential and non-essential trace elements in humans. Commun Biol 2024; 7:432. [PMID: 38594418 PMCID: PMC11004147 DOI: 10.1038/s42003-024-06101-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 03/22/2024] [Indexed: 04/11/2024] Open
Abstract
Trace elements are important for human health but may exert toxic or adverse effects. Mechanisms of uptake, distribution, metabolism, and excretion are partly under genetic control but have not yet been extensively mapped. Here we report a comprehensive multi-element genome-wide association study of 57 essential and non-essential trace elements. We perform genome-wide association meta-analyses of 14 trace elements in up to 6564 Scandinavian whole blood samples, and genome-wide association studies of 43 trace elements in up to 2819 samples measured only in the Trøndelag Health Study (HUNT). We identify 11 novel genetic loci associated with blood concentrations of arsenic, cadmium, manganese, selenium, and zinc in genome-wide association meta-analyses. In HUNT, several genome-wide significant loci are also indicated for other trace elements. Using two-sample Mendelian randomization, we find several indications of weak to moderate effects on health outcomes, the most precise being a weak harmful effect of increased zinc on prostate cancer. However, independent validation is needed. Our current understanding of trace element-associated genetic variants may help establish consequences of trace elements on human health.
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Affiliation(s)
- Marta R Moksnes
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway.
| | - Ailin F Hansen
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Brooke N Wolford
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Laurent F Thomas
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- BioCore-Bioinformatics Core Facility, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- Clinic of Laboratory Medicine, St. Olav's Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Humaira Rasheed
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
- Division of Medicine and Laboratory Sciences, University of Oslo, Oslo, Norway
| | - Anica Simić
- Department of Chemistry, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Laxmi Bhatta
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Anne Lise Brantsæter
- Department of Food Safety, Division of Climate and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Ida Surakka
- Department of Internal Medicine, Division of Cardiology, University of Michigan, Ann Arbor, MI, USA
| | - Wei Zhou
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA, USA
- Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Per Magnus
- Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Pål R Njølstad
- Mohn Center for Diabetes Precision Medicine, Department of Clinical Science, University of Bergen, Bergen, Norway
- Children and Youth Clinic, Haukeland University Hospital, Bergen, Norway
| | - Ole A Andreassen
- NORMENT Centre, University of Oslo, Oslo, Norway
- Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Tore Syversen
- Department of Neuroscience, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Jie Zheng
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai Key Laboratory for Endocrine Tumor, Shanghai Digital Medicine Innovation Center, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- MRC Integrative Epidemiology Unit (IEU), Bristol Medical School, University of Bristol, Bristol, UK
| | - Lars G Fritsche
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, MI, USA
- Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - David M Evans
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Frazer Institute, The University of Queensland, Woolloongabba, QLD, Australia
- MRC Integrative Epidemiology Unit (IEU), University of Bristol, Bristol, UK
| | - Nicole M Warrington
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Frazer Institute, The University of Queensland, Woolloongabba, QLD, Australia
- MRC Integrative Epidemiology Unit (IEU), University of Bristol, Bristol, UK
| | - Therese H Nøst
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- Department of Community Medicine, UiT The Arctic University of Norway, Tromsø, Norway
| | - Bjørn Olav Åsvold
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- HUNT Research Centre, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Levanger, Norway
- Department of Endocrinology, Clinic of Medicine, St. Olav's Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Trond Peder Flaten
- Department of Chemistry, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Cristen J Willer
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Kristian Hveem
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- HUNT Research Centre, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Levanger, Norway
| | - Ben M Brumpton
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway.
- HUNT Research Centre, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Levanger, Norway.
- Clinic of Medicine, St. Olav's Hospital, Trondheim University Hospital, Trondheim, Norway.
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Syversen T, Lilleng G, Vollstad J, Hanssen BJ, Sønvisen SA. Oceanic plastic pollution caused by Danish seine fishing in Norway. Mar Pollut Bull 2022; 179:113711. [PMID: 35533619 DOI: 10.1016/j.marpolbul.2022.113711] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 03/15/2022] [Accepted: 04/25/2022] [Indexed: 06/14/2023]
Abstract
Wear and tear on fishing gear is a sparsely investigated source of microplastic pollution in the sea. In Norway, Danish seine ropes and trawls are the fishing gears that contribute most to this pollution. The main reason for this pollution is that the seine ropes are dragged along the seabed over a considerable distance, creating a friction force that results in high ropes wear. This note reports the findings after examining the wear of Danish seine ropes used in Norwegian fisheries. The results show that, in Norway alone, an average of 77 to 97 tons of plastic will be added to the sea annually due to this specific fishing gear. Aggregated to include all fly dragging, anchor seining, and pair seining globally, this number is estimated to be about 311 tons per year.
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Affiliation(s)
| | | | | | | | - Signe A Sønvisen
- SINTEF Nord, Storgata 118, 9008 Tromsø, Norway; Norwegian College of Fishery Science, The Arctic University of Norway, 9037 Tromsø, Norway
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Simić A, Hansen AF, Syversen T, Lierhagen S, Ciesielski TM, Romundstad PR, Midthjell K, Åsvold BO, Flaten TP. Trace elements in whole blood in the general population in Trøndelag County, Norway: The HUNT3 Survey. Sci Total Environ 2022; 806:150875. [PMID: 34634345 DOI: 10.1016/j.scitotenv.2021.150875] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 10/04/2021] [Accepted: 10/04/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Biomonitoring of a cohort within a large health survey can provide reliable information on trace element status. The main aims of this study were 1) to determine the concentrations of 28 trace elements in whole blood samples from the general population of the Nord-Trøndelag region, Norway, and 2) to investigate how trace element concentrations vary with geographical area, lifestyle, and socio-demographic factors. METHODS Whole blood samples were collected in the third survey of the Trøndelag Health Survey (HUNT3), a large population-based study in Norway. In total, 1011 whole blood samples from individuals aged 20-91 years were analyzed using high resolution inductively coupled plasma-mass spectrometry (HR-ICP-MS). We compared trace element concentrations (As, B, Be, Br, Ca, Cd, Cr, Cs, Cu, Ga, Au, In, Fe, Pb, Hg, Tl, Mg, Mn, Mo, Ni, Rb, Sc, Se, Ag, Sr, Sn, W and Zn) between three geographical areas (coastal, fjord/town, inland/mountain) using multivariable linear regression and assessed differences in trace element concentrations with socio-demographic and lifestyle factors using general linear models. RESULTS Trace element concentrations were generally comparable to levels reported in other recent studies and suggest low exposure to toxic trace elements in the region. We found geographical differences in concentrations of 19 trace elements. As, Br, Hg, and Se concentrations were higher on the coast compared to the fjord/town and inland/mountain areas, suggesting that the marine environment is an important source of exposure for these trace elements. In addition, socio-demographic and lifestyle characteristics, particularly age and sex, were associated with differences in trace element concentrations. CONCLUSIONS We report concentrations of 28 trace elements in the general population of a rural region with low exposure to pollution. Whole blood concentrations of trace elements varied with geographical area, the participants' lifestyle, and socio-demographic characteristics, highlighting the importance of considering these factors when evaluating trace element status in a population.
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Affiliation(s)
- Anica Simić
- Department of Chemistry, NTNU, Norwegian University of Science and Technology, Trondheim, Norway.
| | - Ailin Falkmo Hansen
- Department of Chemistry, NTNU, Norwegian University of Science and Technology, Trondheim, Norway; K.G. Jebsen Center for Genetic Epidemiology, Department of Public Health and Nursing, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Tore Syversen
- Department of Neuroscience, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Syverin Lierhagen
- Department of Chemistry, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | | | - Pål Richard Romundstad
- Department of Public Health and Nursing, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Kristian Midthjell
- HUNT Research Center, Department of Public Health and Nursing, NTNU, Norwegian University of Science and Technology, Levanger, Norway
| | - Bjørn Olav Åsvold
- Department of Chemistry, NTNU, Norwegian University of Science and Technology, Trondheim, Norway; HUNT Research Center, Department of Public Health and Nursing, NTNU, Norwegian University of Science and Technology, Levanger, Norway; Department of Endocrinology, Clinic of Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Trond Peder Flaten
- Department of Chemistry, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
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Abstract
The Nord-Trøndelag Health Study (The HUNT Study) is a large health survey population study in the county of Trøndelag, Norway. The survey has been repeated four times in about 10-year intervals. In the HUNT3 survey (2006-2008), we collected 28,000 samples for trace element analysis. Blood samples from 758 healthy persons without known occupational exposure were selected for multielement analysis of a small sample of blood (0.25 mL). The aim of the study was to determine the minimum blood volume that can be used for the analytical procedure and to compare our results with previously published results of similar surveys in healthy populations. Samples were digested and the concentration of selected trace elements was determined by ICP-MS. We report results on essential elements (B, Co, Cu, Mn, Se and Zn) as well as non-essential elements (As, Be, Br, Cd, Cs, In, La, Pb, Hg, Nd, Ni, Nb, Pd, Pt, Sm, Ta and Sn). Results are similar to previous studies on the HUNT3 population, and with a few exceptions, our data compares very well with results obtained in recent studies from other countries. We wanted to test a minimum volume of blood in a large-scale analytical program. For a number of nonessential elements, our results were below the limit of detection. We suggest that future studies using similar ICP-MS equipment as analytical tool should use at least 0.5 mL of blood.
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Affiliation(s)
- Tore Syversen
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, NTNU, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | - Lars Evje
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, NTNU, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
- Present Address: Department of Earth Science, Faculty of Mathematics and Natural Science, University of Bergen, N-5007 Bergen, Norway
| | - Susann Wolf
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, NTNU, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
- Present Address: National Institute of Occupational Health, N-0363 Oslo, Norway
| | - Trond Peder Flaten
- Department of Chemistry, Faculty of Natural Sciences, NTNU, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | - Syverin Lierhagen
- Department of Chemistry, Faculty of Natural Sciences, NTNU, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | - Anica Simic
- Department of Chemistry, Faculty of Natural Sciences, NTNU, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
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Affiliation(s)
- Tore Syversen
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Trondheim, Eirik Jarlsgt. 10, N-7030 Trondheim, Norway
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Abstract
Neurotoxicology is an exciting area of science, not only because of the importance of toxic injury to the nervous system in human disease, but also because specific toxicants have served as invaluable tools for the advancement of our knowledge of "normal" neurobiological processes. In fact, much of our understanding of the organisation and function of the nervous system is based on observations derived from the actions of neurotoxicants. This paper addresses various physiological aspects behind the exquisite sensitivity of the nervous system to toxic agents, including the privileged status of the nervous system vis-a-vis blood-brain barrier function, the extensions of the nervous system over space and the requirements of cells with such a complex geometry, and the transmission of information across extracellular space. In addition, in vitro models and their utility in the assessment of neurotoxicological outcome are discussed, with reference to both their advantages and disadvantages.
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Affiliation(s)
- Michael Aschner
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1083, USA.
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Hagness M, Foss S, Sørensen DW, Syversen T, Bakkan PA, Dahl T, Fiane A, Line P. Liver Transplant After Normothermic Regional Perfusion From Controlled Donors After Circulatory Death: The Norwegian Experience. Transplant Proc 2019; 51:475-478. [PMID: 30879571 DOI: 10.1016/j.transproceed.2019.01.066] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND In order to meet the increasing demand for donor organs, the concept of donation after circulatory death (DCD) was reintroduced in Norway, first as a pilot study, followed by the use of DCD as institutional practice. We report the current Norwegian experience with liver transplant after DCD. METHODS After acceptance from next of kin, life support was withdrawn from patients with devastating brain injury and cardiac arrest observed. After a 5-minute "no-touch" period, extracorporeal membrane oxygenation for post mortem normothermic regional perfusion (NRP) by extracorporeal membrane oxygenator circuit was established. Data from all liver transplant recipients receiving controlled DCD (cDCD) livers in Oslo were analyzed. RESULTS From 2015 to 2017, a total of 8 patients underwent liver transplant with cDCD and NRP liver grafts in Norway. Median Model for End-Stage Liver Disease score was 26 (range, 6-40). There were no cases of delayed graft function or graft loss. Seven patients have reached 1 year of follow-up, and 1 patient has reached 6 months. Two patients have recurrence of primary disease (primary sclerosing cholangitis and steatohepatitis). All patients had normalized liver function at last follow-up. Two patients underwent procedures for biliary complications. In 1 patient, leakage from the cystic duct was successfully handled endoscopically by stenting. In the other patient, a suspected stricture on magnetic resonance imaging led to an endoscopic retrograde cholangiopancreatography, which did not confirm signs of biliary stenosis. There was 1 instance of hepatic artery stenosis, which was managed with endovascular technique. CONCLUSION The results after liver transplant using cDCD with NRP are good. The rate of complications seems to be within the same range as when using conventional donation after brain death grafts.
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Affiliation(s)
- M Hagness
- Department of Transplantation Medicine, Division of Surgery, Inflammatory Medicine and Transplantation, Oslo University Hospital, Oslo, Norway.
| | - S Foss
- Department of Transplantation Medicine, Division of Surgery, Inflammatory Medicine and Transplantation, Oslo University Hospital, Oslo, Norway
| | - D W Sørensen
- Department of Intensive Care Medicine, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway
| | - T Syversen
- Department of Intensive Care Medicine, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway
| | - P A Bakkan
- Department of Transplantation Medicine, Division of Surgery, Inflammatory Medicine and Transplantation, Oslo University Hospital, Oslo, Norway
| | - T Dahl
- Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway
| | - A Fiane
- Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway; Faculty of Medicine, University of Oslo, Oslo, Norway
| | - P Line
- Department of Transplantation Medicine, Division of Surgery, Inflammatory Medicine and Transplantation, Oslo University Hospital, Oslo, Norway; Faculty of Medicine, University of Oslo, Oslo, Norway
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Simić A, Hansen AF, Åsvold BO, Romundstad PR, Midthjell K, Syversen T, Flaten TP. Trace element status in patients with type 2 diabetes in Norway: The HUNT3 Survey. J Trace Elem Med Biol 2017; 41:91-98. [PMID: 28347468 DOI: 10.1016/j.jtemb.2017.03.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 02/28/2017] [Accepted: 03/01/2017] [Indexed: 12/25/2022]
Abstract
Several epidemiological studies have indicated that a number of trace elements may play a role in type 2 diabetes (T2D). We investigated the association between prevalent T2D and the concentrations of 25 trace elements in whole blood, and the relationships between T2D duration and blood levels of the trace elements that we found to be related to T2D prevalence. In this population based case-control study, 267 patients with self-reported T2D and 609 controls (frequency matched), were selected from the third Nord-Trøndelag Health Survey. Trace element blood levels were determined by high resolution inductively coupled plasma-mass spectrometry. Multivariable conditional logistic regression and multivariable linear regression were used to estimate associations. The prevalence of T2D was positively associated with boron, calcium and silver, and inversely associated with indium, lead and magnesium (Ptrend<0.05). We found no statistical evidence for associations between blood levels of arsenic, bromine, cadmium, cesium, chromium, copper, gallium, gold, manganese, mercury, molybdenum, nickel, rubidium, selenium, strontium, tantalum, thallium, tin and zinc and T2D prevalence. After corrections for multiple testing, associations remained significant for calcium and lead (Qtrend<0.05), and borderline significant for magnesium, silver and boron. With increasing disease duration, higher calcium levels were observed (P<0.05). This study suggests an association between prevalent T2D and blood levels of boron, calcium, indium, lead, magnesium and silver.
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Affiliation(s)
- Anica Simić
- Department of Chemistry, NTNU, Norwegian University of Science and Technology, Trondheim, Norway.
| | - Ailin Falkmo Hansen
- Department of Chemistry, NTNU, Norwegian University of Science and Technology, Trondheim, Norway; Department of Circulation and Medical Imaging, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Bjørn Olav Åsvold
- Department of Endocrinology, St. Olav's Hospital, Trondheim University Hospital, Trondheim, Norway; Department of Public Health and General Practice, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Pål Richard Romundstad
- Department of Public Health and General Practice, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Kristian Midthjell
- Department of Public Health and General Practice, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Tore Syversen
- Department of Neuroscience, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Trond Peder Flaten
- Department of Chemistry, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
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Hansen AF, Simić A, Åsvold BO, Romundstad PR, Midthjell K, Syversen T, Flaten TP. Trace elements in early phase type 2 diabetes mellitus-A population-based study. The HUNT study in Norway. J Trace Elem Med Biol 2017; 40:46-53. [PMID: 28159221 DOI: 10.1016/j.jtemb.2016.12.008] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/18/2016] [Accepted: 12/19/2016] [Indexed: 01/11/2023]
Abstract
Differences in trace elements levels between individuals with type 2 diabetes and controls have been reported in several studies in various body fluids and tissues, but results have been inconsistent. In order to examine trace element levels in the early phase of type 2 diabetes, we investigated the association between whole blood levels of 26 trace elements and the prevalence of previously undiagnosed, screening-detected type 2 diabetes. The study was conducted as a case-control study nested within the third survey of the population-based Nord-Trøndelag Health Study (HUNT3 Survey). Among participants without previously known diabetes, 128 cases of type 2 diabetes were diagnosed in people with a high diabetes risk score (FINDRISC≥15), and frequency-matched for age and sex with 755 controls. Blood samples were analyzed by high resolution inductively coupled plasma mass spectrometry. Associations between trace element levels and the prevalence of previously undiagnosed type 2 diabetes were evaluated with multivariable conditional logistic regression controlling for age, sex, body mass index, waist-to-hip ratio, education, income, smoking and family history of diabetes. The prevalence of previously undiagnosed type 2 diabetes increased across tertiles/quartiles for cadmium, chromium, iron, nickel, silver and zinc, and decreased with increasing quartiles of bromine (Ptrend<0.05). After corrections for multiple testing, associations for chromium remained significant (Qtrend<0.05), while associations for iron and silver were borderline significant. No associations were found for arsenic, boron, calcium, cesium, copper, gallium, gold, indium, lead, magnesium, manganese, mercury, molybdenum, rubidium, selenium, strontium, tantalum, thallium and tin. Our results suggest a possible role of bromine, cadmium, chromium, iron, nickel, silver and zinc in the development of type 2 diabetes.
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Affiliation(s)
- Ailin Falkmo Hansen
- Department of Chemistry, NTNU, Norwegian University of Science and Technology, Trondheim, Norway; Department of Circulation and Medical Imaging, NTNU, Norwegian University of Science and Technology, Trondheim, Norway.
| | - Anica Simić
- Department of Chemistry, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Bjørn Olav Åsvold
- Department of Endocrinology, St. Olav's Hospital, Trondheim University Hospital, Trondheim, Norway; Department of Public Health and General Practice, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Pål Richard Romundstad
- Department of Public Health and General Practice, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Kristian Midthjell
- Department of Public Health and General Practice, NTNU, Norwegian University of Science and Technology, Trondheim, Norway; HUNT Research Centre, Levanger, Norway
| | - Tore Syversen
- Department of Neuroscience, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Trond Peder Flaten
- Department of Chemistry, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
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Aschner M, Syversen T, Souza DO, Rocha JBT. Metallothioneins: Mercury Species-Specific Induction and Their Potential Role in Attenuating Neurotoxicity. Exp Biol Med (Maywood) 2016; 231:1468-73. [PMID: 17018868 DOI: 10.1177/153537020623100904] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Metallothionein (MT) proteins are widespread in bacteria, fungi, plants, and eukaryotic species. They are of low molecular weight (6–7 kDa) and of the 60+ amino acid residues, 20 are cysteines. Functions attributed to MTs include the sequestration and dispersal of metal ions, primarily in zinc and copper homeostasis; regulation of the biosynthesis and activity of zinc metalloproteins, most notably zinc-dependent transcription factors; and cellular cytoprotection from reactive oxygen species, ionizing radiation, electrophilic anticancer drugs and mutagens, and metals. Observations on the abundance of MTs within the central nervous system (CNS) and the identification of a brain-specific isoform, MT-III, suggest that it might have important neurophysiological and neuromodulatory functions. Reinforced by the potential Involvement of MT-III in a number of neurodegenerative disorders, the role of MTs in the CNS has become an intense focus of scientific pursuit. This manuscript represents a survey on the ability of MTs to modulate mercury neurotoxicity, a neurotoxin that has been implied to play an etiologic role in Minamata disease, erethism, and autism, just to name a few.
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Affiliation(s)
- Michael Aschner
- Department of Pediatrics, B-3307 Medical Center North, Vanderbilt University School of Medicine, Nashville, TN 37232-2495, USA.
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Roos PM, Vesterberg O, Syversen T, Flaten TP, Nordberg M. Metal concentrations in cerebrospinal fluid and blood plasma from patients with amyotrophic lateral sclerosis. Biol Trace Elem Res 2013; 151:159-70. [PMID: 23225075 DOI: 10.1007/s12011-012-9547-x] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Accepted: 11/08/2012] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive and fatal degenerative disorder of motor neurons. The cause of this degeneration is unknown, and different causal hypotheses include genetic, viral, traumatic and environmental mechanisms. In this study, we have analyzed metal concentrations in cerebrospinal fluid (CSF) and blood plasma in a well-defined cohort (n = 17) of ALS patients diagnosed with quantitative electromyography. Metal analyses were performed with high-resolution inductively coupled plasma mass spectrometry. Statistically significant higher concentrations of manganese, aluminium, cadmium, cobalt, copper, zinc, lead, vanadium and uranium were found in ALS CSF compared to control CSF. We also report higher concentrations of these metals in ALS CSF than in ALS blood plasma, which indicate mechanisms of accumulation, e.g. inward directed transport. A pattern of multiple toxic metals is seen in ALS CSF. The results support the hypothesis that metals with neurotoxic effects are involved in the pathogenesis of ALS.
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Affiliation(s)
- Per M Roos
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
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12
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Abstract
A concentrated review on the toxicology of inorganic mercury together with an extensive review on the neurotoxicology of methylmercury is presented. The challenges of using inorganic mercury in dental amalgam are reviewed both regarding the occupational exposure and the possible health problems for the dental patients. The two remaining "mysteries" of methylmercury neurotoxicology are also being reviewed; the cellular selectivity and the delayed onset of symptoms. The relevant literature on these aspects has been discussed and some suggestions towards explaining these observations have been presented.
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Affiliation(s)
- Tore Syversen
- Norwegian University of Science and Technology, Department of Neuroscience, Trondheim, Norway.
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13
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Jensen EK, Larsen SY, Nygaard UC, Marioara CD, Syversen T. Early Combination of Material Characteristics and Toxicology Is Useful in the Design of Low Toxicity Carbon Nanofiber. Materials 2012. [PMCID: PMC5449014 DOI: 10.3390/ma5091560] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper describes an approach for the early combination of material characterization and toxicology testing in order to design carbon nanofiber (CNF) with low toxicity. The aim was to investigate how the adjustment of production parameters and purification procedures can result in a CNF product with low toxicity. Different CNF batches from a pilot plant were characterized with respect to physical properties (chemical composition, specific surface area, morphology, surface chemistry) as well as toxicity by in vitro and in vivo tests. A description of a test battery for both material characterization and toxicity is given. The results illustrate how the adjustment of production parameters and purification, thermal treatment in particular, influence the material characterization as well as the outcome of the toxic tests. The combination of the tests early during product development is a useful and efficient approach when aiming at designing CNF with low toxicity. Early quality and safety characterization, preferably in an iterative process, is expected to be efficient and promising for this purpose. The toxicity tests applied are preliminary tests of low cost and rapid execution. For further studies, effects such as lung inflammation, fibrosis and respiratory cancer are recommended for the more in-depth studies of the mature CNF product.
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Affiliation(s)
- Ellen K. Jensen
- Statoil ASA, Stavanger NO-4035, Norway
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +47-95-204-592; Fax: +47-51-990-050
| | - Sten Y. Larsen
- Elkem Carbon AS, PO Box 8040 Vaagsbygd, Kristiansand NO-4675, Norway; E-Mail:
| | - Unni C. Nygaard
- Department of Environmental Immunology, Division of Environmental Medicine, Norwegian Institute of Public Health, PO Box 4404 Nydalen, Oslo NO-0403, Norway; E-Mail:
| | - Calin D. Marioara
- Department of Synthesis and Properties, SINTEF Materials and Chemistry, Trondheim NO-7465, Norway; E-Mail:
| | - Tore Syversen
- Department of Neuroscience, Faculty of Medicine, The Norwegian University of Science and Technology, MTFS, Trondheim NO-7489, Norway; E-Mail:
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14
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Grosse S, Evje L, Syversen T. Silver nanoparticle-induced cytotoxicity in rat brain endothelial cell culture. Toxicol In Vitro 2012; 27:305-13. [PMID: 22954533 DOI: 10.1016/j.tiv.2012.08.024] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 08/01/2012] [Accepted: 08/21/2012] [Indexed: 01/18/2023]
Abstract
Silver nanoparticles (AgNPs) are among the most widely commercialised engineered nanomaterials, because of their antimicrobial properties. They are already commonly used in medical devices, household products and industry. Concerns have been raised about potential adverse health effects due to increasing dispersion of AgNPs in the environment. The present study examined the cytotoxic effects of spherical, citrate-coated AgNPs (10, 50 and 100 nm) in rat brain endothelial (RBE4) cells and investigated whether the observed effects can be explained by the intrinsic toxicity of the particles or the silver ions released from the particles. The results indicated that exposure of RBE4 cells to AgNPs lead to significant reduction in dye uptake as measured with the Neutral red (NR) assay. The effect was found to be related to particle size, surface area, dose and exposure time. In contrast, silver ions increased NR uptake (ca. 10%) in RBE4 cells after 1h, while a reduction in NR uptake was observed after 24h exposure at high concentrations (20-30 μM). Colony formation, as an indicator of proliferation ability, was completely inhibited by AgNPs at concentrations higher than 1 μg/ml. Silver ions had less effect on the colony formation of RBE4 cells than AgNPs.
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Affiliation(s)
- Susann Grosse
- Department of Neuroscience, Norwegian University of Science and Technology, PO Box 8905 MTFS, NO-7491 Trondheim, Norway
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15
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Roos PM, Lierhagen S, Flaten TP, Syversen T, Vesterberg O, Nordberg M. Manganese in cerebrospinal fluid and blood plasma of patients with amyotrophic lateral sclerosis. Exp Biol Med (Maywood) 2012; 237:803-10. [PMID: 22859739 DOI: 10.1258/ebm.2012.011396] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Neurotoxic properties of manganese (Mn) are well documented. It is less known that Mn contributes to the development of neurodegenerative disorders in the general population. This study presents Mn data from patients with amyotrophic lateral sclerosis (ALS) in a well-defined cohort diagnosed by electrophysiological methods. Cerebrospinal fluid (CSF) and plasma were collected from patients and controls. Mn concentrations were analyzed by high-resolution inductively coupled plasma mass spectrometry. Concentrations of Mn were significantly higher in ALS CSF (median 5.67 μg/L) than in CSF from controls (median 2.08 μg/L). Also, ALS CSF Mn concentrations were higher than ALS plasma Mn concentrations (median 0.91 μg/L), suggesting transport of Mn into the central nervous system. The properties of barrier systems between blood and the brain are discussed and the possibility of Mn accumulation contributing to the relentless course of ALS is introduced.
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Affiliation(s)
- Per M Roos
- Institute of Environmental Medicine, Karolinska Institutet, SE-171 77, Stockholm, Sweden
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16
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Hilt B, Heggland I, Aas O, Qvenild T, Svendsen K, Syversen T, Melø I, Sletvold H. Mulige senskader hos tannhelsepersonell etter kvikksølveksponering. Tidsskriftet 2012; 132:1593-4. [DOI: 10.4045/tidsskr.12.0117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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17
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Höfer T, James D, Syversen T, Bowmer T. Estimation of the Acute Inhalation Hazards of Chemicals Based on Route-to-route and Local Endpoint Extrapolation: Experience from Bulk Maritime Transport. Altern Lab Anim 2011; 39:541-56. [DOI: 10.1177/026119291103900609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Data on acute lethal inhalation toxicity from animal studies are commonly required for assessing the hazards to human health of volatile, gaseous and dusty chemicals or their mixtures. The International Maritime Organisation (IMO) made the provision of acute inhalation toxicity data a mandatory requirement for the carriage of bulk liquid chemicals transported by sea in tank ships, thereby creating the need for inhalation data on many hundreds of chemicals in bulk maritime transport. Taking note of previously published proposals for estimating acute inhalation toxicity hazards for chemicals, and the paucity of measured experimental data, an extrapolation method has been developed by the Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) to partly fulfil this need. This method should be seen as a pragmatic approach to the challenge of missing measured experimental test data, with the added benefit of reducing tests in experimental animals. The method is based on a route-to-route (i.e. between-route) extrapolation of information on acute oral and/or dermal toxicity, in combination with data on the potential for irritation and/or corrosion to skin and eyes. The validation of this method was based on the individual evaluation of inhalation toxicity studies for 330 chemicals, including mixtures and many important chemical groups, for which the IMO holds public and industry-confidential data. The authors contend that this extrapolation method offers a reliable basis for hazard evaluation in the context of bulk maritime transport, and the ‘GESAMP inhalation toxicity extrapolation method’ has become part of the IMO regulatory system for the carriage of bulk liquids (i.e. noxious liquid substances) on board tank ships.
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Affiliation(s)
- Thomas Höfer
- Federal Institute for Risk Assessment, Berlin, Germany
| | | | - Tore Syversen
- Norwegian University of Science and Technology, Department of Neuroscience, Faculty of Medicine, Trondheim, Norway
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18
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Abstract
The aim of this study was to see if dental personnel with previous exposure to metallic mercury have later developed disturbances in cognitive function. Ninety-one female participants who had been selected from a previous health survey of dental personnel were investigated neuropsychologically within the following domains: motor function, short-term memory, working memory, executive function, mental flexibility, and visual and verbal long-term memory. The scores were mainly within normal ranges. Relationships between an exposure score, the duration of employment before 1990, and previously measured mercury in urine as independent variables and the neuropsychological findings as dependent variables, were analyzed by multiple linear regression controlling for age, general ability, length of education, alcohol consumption, and previous head injuries. The only relationship that was statistically significant in the hypothesized direction was between the previously measured urine mercury values and visual long-term memory, where the urine values explained 30% of the variability. As the study had a low statistical power and also some other methodological limitations, the results have to be interpreted with caution. Even so, we think it is right to conclude that neuropsychological findings indicative of subsequent cognitive injuries are difficult to find in groups of otherwise healthy dental personnel with previous occupational exposure to mercury.
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Affiliation(s)
- Helge Sletvold
- Department of Industrial Economics and Technology Management, Norwegian University of Science and Technology, Trondheim, Norway
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19
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Kaur P, Aschner M, Syversen T. Biochemical factors modulating cellular neurotoxicity of methylmercury. J Toxicol 2011; 2011:721987. [PMID: 21941541 PMCID: PMC3177097 DOI: 10.1155/2011/721987] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Revised: 06/28/2011] [Accepted: 07/13/2011] [Indexed: 11/30/2022] Open
Abstract
Methylmercury (MeHg), an environmental toxicant primarily found in fish and seafood, poses a dilemma to both consumers and regulatory authorities, given the nutritional benefits of fish consumption versus the possible adverse neurological damage. Several studies have shown that MeHg toxicity is influenced by a number of biochemical factors, such as glutathione (GSH), fatty acids, vitamins, and essential elements, but the cellular mechanisms underlying these complex interactions have not yet been fully elucidated. The objective of this paper is to outline the cellular response to dietary nutrients, as well as to describe the neurotoxic exposures to MeHg. In order to determine the cellular mechanism(s) of toxicity, the effect of pretreatment with biochemical factors (e.g., N-acetyl cysteine, (NAC); diethyl maleate, (DEM); docosahexaenoic acid, (DHA); selenomethionine, SeM; Trolox) and MeHg treatment on intercellular antioxidant status, MeHg content, and other endpoints was evaluated. This paper emphasizes that the protection against oxidative stress offered by these biochemical factors is among one of the major mechanisms responsible for conferring neuroprotection. It is therefore critical to ascertain the cellular mechanisms associated with various dietary nutrients as well as to determine the potential effects of neurotoxic exposures for accurately assessing the risks and benefits associated with fish consumption.
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Affiliation(s)
- Parvinder Kaur
- Department of Neuroscience, Norwegian University of Science and Technology, 7489 Trondheim, Norway
| | - Michael Aschner
- Departments of Pediatrics and Pharmacology and The Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, B-3307 Medical Center North, 1162 21st Avenue, Nashville, TN 37232-2495, USA
| | - Tore Syversen
- Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and Technology, Olav Kyrres Gate 3, 7489 Trondheim, Norway
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20
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Heggland I, Irgens Å, Tollånes M, Romundstad P, Syversen T, Svendsen K, Melø I, Hilt B. Pregnancy outcomes among female dental personnel – a registry-based retrospective cohort study. Scand J Work Environ Health 2011; 37:539-546. [DOI: 10.5271/sjweh.3175] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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21
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Ni M, Li X, Yin Z, Sidoryk-Węgrzynowicz M, Jiang H, Farina M, Rocha JBT, Syversen T, Aschner M. Comparative study on the response of rat primary astrocytes and microglia to methylmercury toxicity. Glia 2011; 59:810-20. [PMID: 21351162 DOI: 10.1002/glia.21153] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 01/11/2011] [Indexed: 12/16/2022]
Abstract
As the two major glial cell types in the brain, astrocytes and microglia play pivotal but different roles in maintaining optimal brain function. Although both cell types have been implicated as major targets of methylmercury (MeHg), their sensitivities and adaptive responses to this metal can vary given their distinctive properties and physiological functions. This study was carried out to compare the responses of astrocytes and microglia following MeHg treatment, specifically addressing the effects of MeHg on cell viability, reactive oxygen species (ROS) generation and glutathione (GSH) levels, as well as mercury (Hg) uptake and the expression of NF-E2-related factor 2 (Nrf2). Results showed that microglia are more sensitive to MeHg than astrocytes, a finding that is consistent with their higher Hg uptake and lower basal GSH levels. Microglia also demonstrated higher ROS generation compared with astrocytes. Nrf2 and its downstream genes were upregulated in both cell types, but with different kinetics (much faster in microglia). In summary, microglia and astrocytes each exhibit a distinct sensitivity to MeHg, resulting in their differential temporal adaptive responses. These unique sensitivities appear to be dependent on the cellular thiol status of the particular cell type.
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Affiliation(s)
- Mingwei Ni
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
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22
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Kaur P, Evje L, Aschner M, Syversen T. The in vitro effects of Trolox on methylmercury-induced neurotoxicity. Toxicology 2010; 276:73-8. [DOI: 10.1016/j.tox.2010.07.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 07/06/2010] [Accepted: 07/07/2010] [Indexed: 10/19/2022]
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23
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Svendsen K, Syversen T, Melø I, Hilt B. Historical exposure to mercury among Norwegian dental personnel. Scand J Work Environ Health 2009; 36:231-41. [DOI: 10.5271/sjweh.2878] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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24
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Hilt B, Svendsen K, Syversen T, Aas O, Qvenild T, Sletvold H, Melø I. Occurrence of cognitive symptoms in dental assistants with previous occupational exposure to metallic mercury. Neurotoxicology 2009; 30:1202-6. [DOI: 10.1016/j.neuro.2009.04.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 04/28/2009] [Accepted: 04/29/2009] [Indexed: 11/24/2022]
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25
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Gellein K, Hoel S, Gellein K, Hoel S, Evje L, Syversen T. The colony formation assay as an indicator of carbon nanotube toxicity examined in three cell lines. Nanotoxicology 2009. [DOI: 10.1080/17435390902906811] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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26
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Heggland I, Kaur P, Syversen T. Uptake and efflux of methylmercury in vitro: Comparison of transport mechanisms in C6, B35 and RBE4 cells. Toxicol In Vitro 2009; 23:1020-7. [DOI: 10.1016/j.tiv.2009.06.018] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 06/10/2009] [Accepted: 06/15/2009] [Indexed: 10/20/2022]
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27
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Jiang GCT, Hughes S, Stürzenbaum SR, Evje L, Syversen T, Aschner M. Caenorhabditis elegans metallothioneins protect against toxicity induced by depleted uranium. Toxicol Sci 2009; 111:345-54. [PMID: 19617453 DOI: 10.1093/toxsci/kfp161] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Depleted uranium (DU) is a dense and heavy metal used in armor, ammunition, radiation shielding, and counterbalances. The military usage has led to growing public concern regarding the health effects of DU. In this study, we used the nematode, Caenorhabditis elegans, to evaluate the toxicity of DU and its effects in knockout strains of metallothioneins (MTs), which are small thiol-rich proteins that have numerous functions, such as metal sequestration, transport, and detoxification. We examined nematode viability, the accumulation of uranium, changes in MT gene expression by quantitative reverse transcription-PCR, and the induction of green fluorescent protein under the control of the MT promoters, following exposure to DU. Our results indicate that (1) DU causes toxicity in a dose-dependent manner; (2) MTs are protective against DU exposure; and (3) nematode death by DU is not solely a reflection of intracellular uranium concentration. (4) Furthermore, only one of the isoforms of MTs, metallothionein-1 (mtl-1), appears to be important for uranium accumulation in C. elegans. These findings suggest that these highly homologous proteins may have subtle functional differences and indicate that MTs mediate the response to DU.
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Affiliation(s)
- George C-T Jiang
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
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28
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Burton NC, Schneider JS, Syversen T, Guilarte TR. Effects of chronic manganese exposure on glutamatergic and GABAergic neurotransmitter markers in the nonhuman primate brain. Toxicol Sci 2009; 111:131-9. [PMID: 19520674 DOI: 10.1093/toxsci/kfp124] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The neurological sequelae of chronic Mn exposure include psychiatric, cognitive, and motor deficits, suggesting the potential involvement of multiple neurotransmitter systems and brain regions. Available evidence in rodents suggests that Mn causes dysregulation of glutamatergic and gamma-aminobutyric acidergic (GABAergic) neurotransmitter systems. However, this has never been studied comprehensively in the nonhuman primate brain. Cynomolgus macaques were given weekly i.v. injections of 3.3-5.0 mg Mn/kg, 5.0-6.7 mg Mn/kg, or 8.3-10.0 mg Mn/kg for 7-59 weeks. Total glutamate, glycine, and GABA concentrations were measured by high performance liquid chromatography (HPLC) with fluorescence detection in 13 brain areas in Mn-treated and control monkeys. Neurotransmitter concentrations did not change with chronic Mn exposure. Quantitative autoradiography of the N-methyl-D-aspartate receptor, the GABAa receptor, and glutamate transporters was used to assess their regional distribution. Each of these neurotransmitter receptors remained almost universally unchanged with Mn treatment. Immunohistochemical analysis of glutamine synthetase (GS) demonstrated a selective Mn-induced decrease in the globus pallidus, which could potentially alter synaptic and/or astrocytic levels of glutamate. This study shows that in nonhuman primates with previous documentation of Mn-induced brain pathology, the glutamatergic and GABAergic systems appear to be mostly unaffected by chronic Mn exposure with the exception of reduced GS expression in the globus pallidus.
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Affiliation(s)
- Neal C Burton
- Department of Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205, USA
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29
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Helmcke KJ, Syversen T, Miller DM, Aschner M. Characterization of the effects of methylmercury on Caenorhabditis elegans. Toxicol Appl Pharmacol 2009; 240:265-72. [PMID: 19341752 DOI: 10.1016/j.taap.2009.03.013] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 03/11/2009] [Accepted: 03/23/2009] [Indexed: 11/19/2022]
Abstract
The rising prevalence of methylmercury (MeHg) in seafood and in the global environment provides an impetus for delineating the mechanism of the toxicity of MeHg. Deleterious effects of MeHg have been widely observed in humans and in other mammals, the most striking of which occur in the nervous system. Here we test the model organism, Caenorhabditis elegans (C. elegans), for MeHg toxicity. The simple, well-defined anatomy of the C. elegans nervous system and its ready visualization with green fluorescent protein (GFP) markers facilitated our study of the effects of methylmercuric chloride (MeHgCl) on neural development. Although MeHgCl was lethal to C. elegans, induced a developmental delay, and decreased pharyngeal pumping, other traits including lifespan, brood size, swimming rate, and nervous system morphology were not obviously perturbed in animals that survived MeHgCl exposure. Despite the limited effects of MeHgCl on C. elegans development and behavior, intracellular mercury (Hg) concentrations (<or=3 ng Hg/mg protein) in MeHgCl-treated nematodes approached levels that are highly toxic to mammals. If MeHgCl reaches these concentrations throughout the animal, this finding indicates that C. elegans cells, particularly neurons, may be less sensitive to MeHgCl toxicity than mammalian cells. We propose, therefore, that C. elegans should be a useful model for discovering intrinsic mechanisms that confer resistance to MeHgCl exposure.
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Affiliation(s)
- Kirsten J Helmcke
- Pharmacology Department, Vanderbilt University Medical Center, Nashville, TN 37232-0414, USA
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30
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Schneider JS, Decamp E, Clark K, Bouquio C, Syversen T, Guilarte TR. Effects of chronic manganese exposure on working memory in non-human primates. Brain Res 2009; 1258:86-95. [PMID: 19133246 PMCID: PMC2659542 DOI: 10.1016/j.brainres.2008.12.035] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Revised: 12/10/2008] [Accepted: 12/12/2008] [Indexed: 10/21/2022]
Abstract
Human exposure to manganese (Mn) has been associated with a variety of cognitive deficits including learning and memory deficits. However, results from epidemiological studies have been inconsistent in describing the nature of such cognitive deficits. The present study was conducted to evaluate the effects of chronic Mn exposure on memory functioning in non-human primates and to correlate behavioral outcome with brain Mn levels in an attempt to explain outcome variability seen in prior studies. Cynomolgus macaque monkeys were trained to perform memory-related tasks (spatial working memory, non-spatial working memory, reference memory) and exposed to manganese sulfate (15-20 mg/kg/week) over an exposure period lasting 227.5+/-17.3 days. Blood manganese levels were in the upper range of levels reported for human environmental, medical or occupational exposures. By the end of the manganese exposure period, animals developed mild deficits in spatial working memory, more significant deficits in non-spatial working memory and no deficits in reference memory. Linear regression analyses showed that for most brain regions sampled, there was a significant inverse relationship between working memory task performance and brain Mn concentration. These results suggest that chronic exposure to levels of manganese achieved in this study may have detrimental effects on working memory and that Mn levels achieved in several brain regions are inversely related to working memory performance.
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Affiliation(s)
- J S Schneider
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, 1020 Locust Street, 521 JAH, Philadelphia, PA 19107, USA.
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31
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Yin Z, Albrecht J, Syversen T, Jiang H, Summar M, Rocha JBT, Farina M, Aschner M. Comparison of alterations in amino acids content in cultured astrocytes or neurons exposed to methylmercury separately or in co-culture. Neurochem Int 2009; 55:136-42. [PMID: 19428818 DOI: 10.1016/j.neuint.2009.01.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 01/20/2009] [Accepted: 01/21/2009] [Indexed: 10/21/2022]
Abstract
Methylmercury (MeHg) is an environmental toxicant that induces enduring neuropsychological deficits in humans. Although the mechanisms associated with MeHg-induced neurotoxicity have not yet been fully elucidated, some lines of evidence point out to excitatory amino acids dyshomeostasis as an important outcome of MeHg exposure. The present study was designed to characterize the effects of MeHg on amino acid content in co-cultured astrocytes and neurons or in each cell type under solitary conditions. The results showed that glutamate concentrations significantly decreased in neurons, but not in astrocyte cultures exposed to 10 microM MeHg. The decrease in neurons was fully reversed when these cells were co-cultured with astrocytes. The content of other amino acids (aspartate, alanine, glycine and serine) decreased upon exposure to 10 microM MeHg in both neurons and astrocytes cultured in solitary conditions, although the effect was generally smaller in astrocytes than in neurons. However, the content of these amino acids in each of the cell types was indistinguishable from controls when co-cultures were treated with MeHg. Overall, the results indicate that astrocytes, which are more resistant to amino acid modulation by MeHg, can (i) mitigate the effects of MeHg that occur in neurons cultured in solitary conditions and (ii) become themselves more MeHg resistant in the presence of neurons. Delineating the mechanisms underlying the mutual neuroprotective effects of astrocytes and neurons in co-culture to MeHg-induced amino acid imbalance requires further investigation.
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Affiliation(s)
- Zhaobao Yin
- Department of Pediatrics, and the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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32
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Slørdahl TS, Hov H, Holt RU, Baykov V, Syversen T, Sundan A, Waage A, Børset M. Mn2+regulates myeloma cell adhesion differently than the proadhesive cytokines HGF, IGF-1, and SDF-1α. Eur J Haematol 2008; 81:437-47. [DOI: 10.1111/j.1600-0609.2008.01148.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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33
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Kaur P, Heggland I, Aschner M, Syversen T. Docosahexaenoic acid may act as a neuroprotector for methylmercury-induced neurotoxicity in primary neural cell cultures. Neurotoxicology 2008; 29:978-87. [DOI: 10.1016/j.neuro.2008.06.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Revised: 06/02/2008] [Accepted: 06/09/2008] [Indexed: 10/21/2022]
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Guilarte TR, Burton NC, McGlothan JL, Verina T, Zhou Y, Alexander M, Pham L, Griswold M, Wong DF, Syversen T, Schneider JS. Impairment of nigrostriatal dopamine neurotransmission by manganese is mediated by pre-synaptic mechanism(s): implications to manganese-induced parkinsonism. J Neurochem 2008; 107:1236-47. [PMID: 18808452 DOI: 10.1111/j.1471-4159.2008.05695.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The long-term consequences of chronic manganese (Mn) exposure on neurological health is a topic of great concern to occupationally-exposed workers and in populations exposed to moderate levels of Mn. We have performed a comprehensive assessment of Mn effects on dopamine (DA) synapse markers using positron emission tomography (PET) in the non-human primate brain. Young male Cynomolgus macaques were given weekly i.v. injections of 3.3-5.0 mg Mn/kg (n = 4), 5.0-6.7 mg Mn/kg (n = 5), or 8.3-10.0 mg Mn/kg (n = 3) for 7-59 weeks and received PET studies of various DA synapse markers before (baseline) and at one or two time points during the course of Mn exposure. We report that amphetamine-induced DA release measured by PET is markedly impaired in the striatum of Mn-exposed animals. The effect of Mn on DA release was present in the absence of changes in markers of dopamine terminal integrity determined in post-mortem brain tissue from the same animals. These findings provide compelling evidence that the effects of Mn on DA synapses in the striatum are mediated by inhibition of DA neurotransmission and are responsible for the motor deficits documented in these animals.
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Affiliation(s)
- Tomás R Guilarte
- Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, USA.
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Yin Z, Jiang H, Syversen T, Rocha JBT, Farina M, Aschner M. The methylmercury-L-cysteine conjugate is a substrate for the L-type large neutral amino acid transporter. J Neurochem 2008; 107:1083-90. [PMID: 18793329 DOI: 10.1111/j.1471-4159.2008.05683.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Methylmercury (MeHg) is a potent neurotoxin. The mechanism(s) that governs MeHg transport across the blood-brain barrier and other biological membranes remains unclear. This study addressed the role of the L-type large neutral amino acid transporter, LAT1, in MeHg transport. Studies were carried out in CHO-k1 cells. Over-expression of LAT1 in these cells was associated with enhanced uptake of [(14)C]-MeHg when treated with L-cysteine, but not with the D-cysteine conjugate. In the presence of excess L-methionine, a substrate for LAT1, L-cysteine-conjugated [(14)C]-MeHg uptake was significantly attenuated. Treatment of LAT-1 over-expressing CHO-k1 cells with L-cysteine-conjugated MeHg was also associated with increased leakage of lactate dehydrogenase into the media as well as reduced cell viability measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assay. In contrast, knock-down of LAT1 decreased the uptake of l-cysteine-conjugated MeHg and attenuated the effects of MeHg on lactate dehydrogenase leakage and CHO-k1 cell viability. These results indicate that the MeHg-L-cysteine conjugate is a substrate for the neutral amino acid transporter, LAT1, which actively transports MeHg across membranes.
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Affiliation(s)
- Zhaobao Yin
- Department of Pediatrics, Kennedy Center for Research on human Development, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
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36
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Kaur P, Schulz K, Heggland I, Aschner M, Syversen T. The use of fluorescence for detecting MeHg-induced ROS in cell cultures. Toxicol In Vitro 2008; 22:1392-8. [DOI: 10.1016/j.tiv.2008.01.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 01/23/2008] [Accepted: 01/31/2008] [Indexed: 11/16/2022]
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37
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Gellein K, Syversen T, Steinnes E, Nilsen TIL, Dahl OP, Mitrovic S, Duraj D, Flaten TP. Trace elements in serum from patients with Parkinson's disease — a prospective case-control study. Brain Res 2008; 1219:111-5. [DOI: 10.1016/j.brainres.2008.05.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Revised: 04/30/2008] [Accepted: 05/01/2008] [Indexed: 10/22/2022]
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Gellein K, Skogholt JH, Aaseth J, Thoresen GB, Lierhagen S, Steinnes E, Syversen T, Flaten TP. Trace elements in cerebrospinal fluid and blood from patients with a rare progressive central and peripheral demyelinating disease. J Neurol Sci 2008; 266:70-8. [PMID: 17900623 DOI: 10.1016/j.jns.2007.08.042] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Revised: 08/28/2007] [Accepted: 08/30/2007] [Indexed: 10/22/2022]
Abstract
A hereditary neurological disease in a family in Norway has been reported recently. The disease, which we refer to as Skogholt's disease, is a demyelinating disorder of both the central and the peripheral nervous system with adult onset. We investigated whether changes in trace element concentrations could play a role in Skogholt's disease. Using high resolution inductively coupled plasma mass spectrometry, we determined 31 elements in cerebrospinal fluid (CSF), blood plasma and whole blood from these patients, multiple sclerosis patients and a control group. More than threefold increased levels of Cu and Fe, and a twofold increase in Zn were found in the CSF of Skogholt patients compared to controls. Several other significant differences in trace element levels were also found. The increased levels of Cu and Fe in CSF may indicate an active role of these metals in the pathogenesis of Skogholt's disease. Apparently, these metal ions are transferred into the CSF through their protein chelation, as raised protein levels were also seen. We suggest that redistribution of metals from transport proteins into vulnerable sites in the central (and peripheral) nervous system may initiate critical lesions.
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Affiliation(s)
- Kristin Gellein
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
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Gellein K, Flaten TP, Erikson KM, Aschner M, Syversen T. Leaching of trace elements from biological tissue by formalin fixation. Biol Trace Elem Res 2008; 121:221-5. [PMID: 17952381 DOI: 10.1007/s12011-007-8051-1] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Accepted: 09/25/2007] [Indexed: 11/26/2022]
Abstract
In studies of trace elements in biological tissue, it is imperative that sample handling does not substantially change element concentrations. In many cases, fresh tissue is not available for study, but formalin-fixed tissue is. Formalin fixation has the potential to leach elements from the tissue, but few studies have been published in this area. The concentrations of 19 elements were determined by high-resolution inductively coupled plasma mass spectrometry in formalin in which human and rat brain samples had been stored for different time durations ranging from weeks up to several years. Additional analysis was carried out in fixed brain samples. There was substantial leaching of elements from the tissue into the formalin, and the leaching varied considerably between different elements. For example, formalin concentrations of As, Cd, Mg, Rb, and Sb increased more than 100-fold upon long-term (years) storage, while for Ni and Cr, the leaching was negligible. The degree of leaching was strongly time-dependent. In conclusion, formalin fixation and storage of biological tissue has the potential to leach substantial fractions of several trace elements from the tissue. The potential of leaching must be critically considered when using formalin-fixed biological tissue in trace metal analysis.
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Affiliation(s)
- Kristin Gellein
- Department of Chemistry, Norwegian University of Science and Technology, Trondheim, Norway
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40
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Guilarte TR, Burton NC, Verina T, Prabhu VV, Becker KG, Syversen T, Schneider JS. Increased APLP1 expression and neurodegeneration in the frontal cortex of manganese-exposed non-human primates. J Neurochem 2008; 105:1948-59. [PMID: 18284614 DOI: 10.1111/j.1471-4159.2008.05295.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Chronic manganese (Mn) exposure produces a neurological syndrome with psychiatric, cognitive, and parkinsonian features. Gene expression profiling in the frontal cortex of Cynomologous macaques receiving 3.3-5.0 mg Mn/kg weekly for 10 months showed that 61 genes were increased and four genes were decreased relative to controls from a total of 6766 genes. Gene changes were associated with cell cycle regulation, DNA repair, apoptosis, ubiquitin-proteasome system, protein folding, cholesterol homeostasis, axonal/vesicular transport, and inflammation. Amyloid-beta (Abeta) precursor-like protein 1, a member of the amyloid precursor protein family, was the most highly up-regulated gene. Immunohistochemistry confirmed increased amyloid precursor-like protein 1 protein expression and revealed the presence of diffuse Abeta plaques in Mn-exposed frontal cortex. Cortical neurons and white matter fibers from Mn-exposed animals accumulated silver grains indicative of on-going degeneration. Cortical neurons also exhibited nuclear hypertrophy, intracytoplasmic vacuoles, and apoptosis stigmata. p53 immunolabeling was increased in the cytoplasm of neurons and in the nucleus and processes of glial cells in Mn-exposed tissue. In summary, chronic Mn exposure produces a cellular stress response leading to neurodegenerative changes and diffuse Abeta plaques in the frontal cortex. These changes may explain the subtle cognitive deficits previously demonstrated in these same animals.
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Affiliation(s)
- Tomás R Guilarte
- Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205, USA.
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41
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Gellein K, Lierhagen S, Brevik PS, Teigen M, Kaur P, Singh T, Flaten TP, Syversen T. Trace element profiles in single strands of human hair determined by HR-ICP-MS. Biol Trace Elem Res 2008; 123:250-60. [PMID: 18286238 DOI: 10.1007/s12011-008-8104-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Accepted: 01/21/2008] [Indexed: 11/24/2022]
Abstract
Trace element analysis of human hair has the potential to reveal retrospective information about an individual's nutritional status and exposure. As trace elements are incorporated into the hair during the growth process, longitudinal segments of the hair may reflect the body burden during the growth period. We have evaluated the potential of human hair to indicate exposure or nutritional status over time by analysing trace element profiles in single strands of human hair. The hair strands from five healthy and occupationally unexposed subjects were cut into 1-cm long segments starting from the scalp. By using high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS), we achieved profiles of 12 elements in single strands of human hair, namely, Ag, As, Au, Cd, Cu, Hg, Fe, Pb, Se, Sr, U and Zn. We have shown that trace element analysis along single strands of human hair can yield information about essential and toxic elements, and for some elements, can be correlated with seasonal changes in diet and exposure. The information obtained from the trace element profiles of human hair in this study substantiates the potential of hair as a biomarker.
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Affiliation(s)
- Kristin Gellein
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491, Trondheim, Norway.
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42
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Abstract
The effect of docosahexaenoic acid (DHA) in modulating methylmercury (MeHg)-induced neurotoxicity was investigated in C6-glial and B35-neuronal cell lines. Gas chromatography measurements indicated increased DHA content in both the cell lines after 24 h supplementation. Mitochondrial activity evaluated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5 diphenyltetrazolium bromide (MTT) reduction indicated that 10 microM MeHg treatment for 50 min led to a significant (p < 0.001) and similar decrease in MTT activity in both the cell lines. However, DHA pretreatment led to more pronounced depletion (p < 0.05) in the MTT activity in C6 cells as compared to B35 cells. The depletion of glutathione (GSH) content measured with the fluorescent indicator monochlorobimane was more apparent (p < 0.001) in C6 cells treated with DHA and MeHg. The amount of reactive oxygen species (ROS) detected with the fluorescent indicator -- chloromethyl derivative of dichloro dihydro fluorescein diacetate (CMH(2)DCFDA) -- indicated a fourfold increase in C6 cells (p < 0.001) as compared to twofold increase in B35 cells (p < 0.001) upon DHA and MeHg exposure. However, the cell-associated MeHg measurement using (14)C-labeled MeHg indicated a decrease (p < 0.05) in MeHg accumulation upon DHA exposure in both the cell lines. These findings provide experimental evidence that although pretreatment with DHA reduces cell-associated MeHg, it causes an increased ROS (p < 0.001) and GSH depletion (p < 0.05) in C6 cells.
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Affiliation(s)
- Parvinder Kaur
- Department of Neuroscience, Norwegian University of Science and Technology, N-7489, Trondheim, Norway.
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43
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Gellein K, Roos PM, Evje L, Vesterberg O, Flaten TP, Nordberg M, Syversen T. Separation of proteins including metallothionein in cerebrospinal fluid by size exclusion HPLC and determination of trace elements by HR-ICP-MS. Brain Res 2007; 1174:136-42. [PMID: 17868660 DOI: 10.1016/j.brainres.2007.08.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Revised: 08/02/2007] [Accepted: 08/02/2007] [Indexed: 11/23/2022]
Abstract
A method to study the protein binding patterns of trace elements in human cerebrospinal fluid (CSF) is described. Proteins in CSF samples were separated by size exclusion chromatography combined with high performance liquid chromatography (SEC-HPLC). The column was calibrated to separate proteins in the molecular weight range 6-70 kDa. Fractions were then analyzed off-line for trace elements using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). We were able to accurately determine more than 10 elements of clinical interest in the CSF fractions. Results are presented for Cd, Mn, Fe, Pb, Cu and Zn. The total concentrations of 16 trace elements in human plasma and CSF are also presented. The method was able to differentiate the relative contribution of metallothionein and other proteins towards metal binding in human CSF.
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Affiliation(s)
- Kristin Gellein
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
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44
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Aschner M, Syversen T, Souza DO, Rocha JBT, Farina M. Involvement of glutamate and reactive oxygen species in methylmercury neurotoxicity. Braz J Med Biol Res 2007; 40:285-91. [PMID: 17334523 DOI: 10.1590/s0100-879x2007000300001] [Citation(s) in RCA: 223] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Accepted: 01/16/2007] [Indexed: 01/08/2023] Open
Abstract
This review addresses the mechanisms of methylmercury (MeHg)-induced neurotoxicity, specifically examining the role of oxidative stress in mediating neuronal damage. A number of critical findings point to a central role for astrocytes in mediating MeHg-induced neurotoxicity as evidenced by the following observations: a) MeHg preferentially accumulates in astrocytes; b) MeHg specifically inhibits glutamate uptake in astrocytes; c) neuronal dysfunction is secondary to disturbances in astrocytes. The generation of reactive oxygen species (ROS) by MeHg has been observed in various experimental paradigms. For example, MeHg enhances ROS formation both in vivo (rodent cerebellum) and in vitro (isolated rat brain synaptosomes), as well as in neuronal and mixed reaggregating cell cultures. Antioxidants, including selenocompounds, can rescue astrocytes from MeHg-induced cytotoxicity by reducing ROS formation. We emphasize that oxidative stress plays a significant role in mediating MeHg-induced neurotoxic damage with active involvement of the mitochondria in this process. Furthermore, we provide a mechanistic overview on oxidative stress induced by MeHg that is triggered by a series of molecular events such as activation of various kinases, stress proteins and other immediate early genes culminating in cell damage.
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Affiliation(s)
- M Aschner
- Departments of Pediatrics and Pharmacology, Vanderbilt University Medical Center, B3307 Medical Center North, Nashville, TN 37232, USA.
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Kaur P, Aschner M, Syversen T. Role of glutathione in determining the differential sensitivity between the cortical and cerebellar regions towards mercury-induced oxidative stress. Toxicology 2007; 230:164-77. [PMID: 17169475 DOI: 10.1016/j.tox.2006.11.058] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Revised: 11/06/2006] [Accepted: 11/09/2006] [Indexed: 11/25/2022]
Abstract
Certain discrete areas of the CNS exhibit enhanced sensitivity towards MeHg. To determine whether GSH is responsible for this particular sensitivity, we investigated its role in MeHg-induced oxidative insult in primary neuronal and astroglial cell cultures of both cerebellar and cortical origins. For this purpose, ROS and GSH were measured with the fluorescent indicators, CMH(2)DCFDA and MCB. Cell associated-MeHg was measured with (14)C-radiolabeled MeHg. The intracellular GSH content was modified by pretreatment with NAC or DEM. For each of the dependent variables (ROS, GSH, and MTT), there was an overall significant effect of cellular origin, MeHg and pretreatment in all the cell cultures. A trend towards significant interaction between originxMeHgxpretreatment was observed only for the dependent variable, ROS (astrocytes p=0.056; neurons p=0.000). For GSH, a significant interaction between originxMeHg was observed only in astrocytes (p=0.030). The cerebellar cell cultures were more vulnerable (astrocytes(mean)=223.77; neurons(mean)=138.06) to ROS than the cortical cell cultures (astrocytes(mean)=125.18; neurons(mean)=107.91) for each of the tested treatments. The cell associated-MeHg increased when treated with DEM, and the cerebellar cultures varied significantly from the cortical cultures. Non-significant interactions between originxMeHgxpretreatment for GSH did not explain the significant interactions responsible for the increased amount of ROS produced in these cultures. In summary, although GSH modulation influences MeHg-induced toxicity, the difference in the content of GSH in cortical and cerebellar cultures fails to account for the increased ROS production in cerebellar cultures. Hence, different approaches for the future studies regarding the mechanisms behind selectivity of MeHg have been discussed.
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Affiliation(s)
- Parvinder Kaur
- Department of Neuroscience, Norwegian University of Science and Technology, N-7489 Trondheim, Norway
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46
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Yin Z, Milatovic D, Aschner JL, Syversen T, Rocha JB, Souza DO, Sidoryk M, Albrecht J, Aschner M. Methylmercury induces oxidative injury, alterations in permeability and glutamine transport in cultured astrocytes. Brain Res 2006; 1131:1-10. [PMID: 17182013 PMCID: PMC1847599 DOI: 10.1016/j.brainres.2006.10.070] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Revised: 10/09/2006] [Accepted: 10/26/2006] [Indexed: 01/12/2023]
Abstract
The neurotoxicity of high levels of methylmercury (MeHg) is well established both in humans and experimental animals. Astrocytes accumulate MeHg and play a prominent role in mediating MeHg toxicity in the central nervous system (CNS). Although the precise mechanisms of MeHg neurotoxicity are ill-defined, oxidative stress and altered mitochondrial and cell membrane permeability appear to be critical factors in its pathogenesis. The present study examined the effects of MeHg treatment on oxidative injury, mitochondrial inner membrane potential, glutamine uptake and expression of glutamine transporters in primary astrocyte cultures. MeHg caused a significant increase in F(2)-isoprostanes (F(2)-IsoPs), lipid peroxidation biomarkers of oxidative damage, in astrocyte cultures treated with 5 or 10 microM MeHg for 1 or 6 h. Consistent with this observation, MeHg induced a concentration-dependant reduction in the inner mitochondrial membrane potential (DeltaPsi(m)), as assessed by the potentiometric dye, tetramethylrhodamine ethyl ester (TMRE). Our results demonstrate that DeltaPsi(m) is a very sensitive endpoint for MeHg toxicity, since significant reductions were observed after only 1 h exposure to concentrations of MeHg as low as 1 microM. MeHg pretreatment (1, 5 and 10 microM) for 30 min also inhibited the net uptake of glutamine ((3)H-glutamine) measured at 1 min and 5 min. Expression of the mRNA coding the glutamine transporters, SNAT3/SN1 and ASCT2, was inhibited only at the highest (10 microM) MeHg concentration, suggesting that the reduction in glutamine uptake observed after 30 min treatment with lower concentrations of MeHg (1 and 5 microM) was not due to inhibition of transcription. Taken together, these studies demonstrate that MeHg exposure is associated with increased mitochondrial membrane permeability, alterations in glutamine/glutamate cycling, increased ROS formation and consequent oxidative injury. Ultimately, MeHg initiates multiple additive or synergistic disruptive mechanisms that lead to cellular dysfunction and cell death.
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MESH Headings
- Amino Acid Transport Systems, Neutral/genetics
- Animals
- Animals, Newborn
- Astrocytes/drug effects
- Astrocytes/metabolism
- Astrocytes/pathology
- Cell Membrane Permeability/drug effects
- Cell Membrane Permeability/physiology
- Cells, Cultured
- Central Nervous System/drug effects
- Central Nervous System/metabolism
- Central Nervous System/physiopathology
- Dose-Response Relationship, Drug
- Glutamic Acid/metabolism
- Glutamine/metabolism
- Lipid Peroxidation/drug effects
- Lipid Peroxidation/physiology
- Membrane Potential, Mitochondrial/drug effects
- Membrane Potential, Mitochondrial/physiology
- Mercury Poisoning, Nervous System/metabolism
- Mercury Poisoning, Nervous System/physiopathology
- Methylmercury Compounds/toxicity
- Mitochondria/drug effects
- Mitochondria/metabolism
- Mitochondria/pathology
- Mitochondrial Membranes/drug effects
- Mitochondrial Membranes/metabolism
- Mitochondrial Membranes/pathology
- Oxidative Stress/drug effects
- Oxidative Stress/physiology
- RNA, Messenger/drug effects
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Reactive Oxygen Species/metabolism
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Affiliation(s)
- Zhaobao Yin
- Department of Pediatrics, Pharmacology, and the Kennedy Center, Norwegian University of Science and Technology, Trondheim, Norway
| | - Dejan Milatovic
- Department of Pediatrics, Pharmacology, and the Kennedy Center, Norwegian University of Science and Technology, Trondheim, Norway
| | - Judy L. Aschner
- Department of Pediatrics, Pharmacology, and the Kennedy Center, Norwegian University of Science and Technology, Trondheim, Norway
| | - Tore Syversen
- Department of Clinical Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway
| | - Joao B.T. Rocha
- Departamento de Análises Clínicas e Toxicológicas, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Brazil
| | - Diogo O. Souza
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Marta Sidoryk
- Department of Neurotoxicology, Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Jan Albrecht
- Department of Neurotoxicology, Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Michael Aschner
- Department of Pediatrics, Pharmacology, and the Kennedy Center, Norwegian University of Science and Technology, Trondheim, Norway
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47
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Schneider JS, Decamp E, Koser AJ, Fritz S, Gonczi H, Syversen T, Guilarte TR. Effects of chronic manganese exposure on cognitive and motor functioning in non-human primates. Brain Res 2006; 1118:222-31. [PMID: 16978592 PMCID: PMC1892239 DOI: 10.1016/j.brainres.2006.08.054] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Revised: 08/04/2006] [Accepted: 08/08/2006] [Indexed: 11/16/2022]
Abstract
Acute exposure to manganese is associated with complex behavioral/psychiatric signs that may include Parkinsonian motor features. However, little is known about the behavioral consequences of chronic manganese exposures. In this study, cynomolgus macaque monkeys were exposed to manganese sulfate (10-15 mg/kg/week) over an exposure period lasting 272+/-17 days. Prior to manganese exposure, animals were trained to perform tests of cognitive and motor functioning and overall behavior was assessed by ratings and by videotaped analyses. By the end of the manganese exposure period, animals developed subtle deficits in spatial working memory and had modest decreases in spontaneous activity and manual dexterity. In addition, stereotypic or compulsive-like behaviors such as compulsive grooming increased in frequency by the end of the manganese exposure period. Blood manganese levels measured at the end of the manganese exposure period ranged from 29.4 to 73.7 micro g/l (mean=55.7+/-10.8 (compared to levels of 5.1-14.2 micro g/l at baseline (mean=9.2+/-2.7)), placing them within the upper range of levels reported for human environmental, medical or occupational exposures. These results suggest that chronic exposure to levels of manganese achieved in this study may have detrimental effects on behavior, cognition and motor functioning.
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Affiliation(s)
- Jay S Schneider
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, 521 JAH, Philadelphia, PA 19107, USA.
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48
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Garcia SJ, Gellein K, Syversen T, Aschner M. Iron deficient and manganese supplemented diets alter metals and transporters in the developing rat brain. Toxicol Sci 2006; 95:205-14. [PMID: 17060373 DOI: 10.1093/toxsci/kfl139] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Manganese (Mn) neurotoxicity in adults can result in psychological and neurological disturbances similar to Parkinson's disease, including extrapyramidal motor system defects and altered behaviors. Iron (Fe) deficiency is one of the most prevalent nutritional disorders in the world, affecting approximately 2 billion people, especially pregnant and lactating women, infants, toddlers, and adolescents. Fe deficiency can enhance brain Mn accumulation even in the absence of excess Mn in the environment or the diet. To assess the neurochemical interactions of dietary Fe deficiency and excess Mn during development, neonatal rats were exposed to either a control diet, a low-Fe diet (ID), or a low-Fe diet supplemented with Mn (IDMn) via maternal milk during the lactation period (postnatal days [PN] 4-21). In PN21 pups, both the ID and IDMn diets produced changes in blood parameters characteristic of Fe deficiency: decreased hemoglobin (Hb) and plasma Fe, increased plasma transferrin (Tf), and total iron binding capacity (TIBC). Treated ID and IDMn dams also had decreased Hb throughout lactation and ID dams had decreased plasma Fe and increased Tf and TIBC on PN21. Both ID and IDMn pups had decreased Fe and increased copper brain levels; in addition, IDMn pups also had increased brain levels of several other essential metals including Mn, chromium, zinc, cobalt, aluminum, molybdenum, and vanadium. Concurrent with altered concentrations of metals in the brain, transport proteins divalent metal transporter-1 and transferrin receptor were increased. No significant changes were determined for the neurotransmitters gamma aminobutyric acid and glutamate. The results of this study confirm that there is homeostatic relationship among several essential metals in the brain and not simply between Fe and Mn.
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Affiliation(s)
- Stephanie J Garcia
- Department of Physiology & Pharmacology, Wake Forest University Health Sciences, Winston Salem, North Carolina 27157, USA
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Guilarte TR, McGlothan JL, Degaonkar M, Chen MK, Barker PB, Syversen T, Schneider JS. Evidence for cortical dysfunction and widespread manganese accumulation in the nonhuman primate brain following chronic manganese exposure: a 1H-MRS and MRI study. Toxicol Sci 2006; 94:351-8. [PMID: 16968886 DOI: 10.1093/toxsci/kfl106] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Exposure to high levels of manganese (Mn) is known to produce a complex neurological syndrome with psychiatric disturbances, cognitive impairment, and parkinsonian features. However, the neurobiological basis of chronic low-level Mn exposure is not well defined. We now provide evidence that exposure to levels of Mn that results in blood Mn concentrations in the upper range of environmental and occupational exposures and in certain medical conditions produces widespread Mn accumulation in the nonhuman primate brain as visualized by T1-weighted magnetic resonance imaging. Analysis of regional brain Mn distribution using a "pallidal index equivalent" indicates that this approach is not sensitive to changing levels of brain Mn measured in postmortem tissue. Evaluation of longitudinal 1H-magnetic resonance spectroscopy data revealed a significant decrease (p = 0.028) in the N-acetylaspartate (NAA)/creatine (Cr) ratio in the parietal cortex and a near significant decrease (p = 0.055) in frontal white matter (WM) at the end of the Mn exposure period relative to baseline. Choline/Cr or myo-Inositol/Cr ratios did not change at any time during Mn exposure. This indicates that the changes in the NAA/Cr ratio in the parietal cortex are not due to changes in Cr but in NAA levels. In summary, these findings suggest that during chronic Mn exposure a significant amount of the metal accumulates not only in the basal ganglia but also in WM and in cortical structures where it is likely to produce toxic effects. This is supported by a significantly decreased, in the parietal cortex, NAA/Cr ratio suggestive of ongoing neuronal degeneration or dysfunction.
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Affiliation(s)
- Tomás R Guilarte
- Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, USA.
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Guilarte TR, Chen MK, McGlothan JL, Verina T, Wong DF, Zhou Y, Alexander M, Rohde CA, Syversen T, Decamp E, Koser AJ, Fritz S, Gonczi H, Anderson DW, Schneider JS. Nigrostriatal dopamine system dysfunction and subtle motor deficits in manganese-exposed non-human primates. Exp Neurol 2006; 202:381-90. [PMID: 16925997 DOI: 10.1016/j.expneurol.2006.06.015] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Revised: 06/23/2006] [Accepted: 06/30/2006] [Indexed: 10/24/2022]
Abstract
We tested the hypothesis that movement abnormalities induced by chronic manganese (Mn) exposure are mediated by dysfunction of the nigrostriatal dopamine system in the non-human primate striatum. Motor function and general activity of animals was monitored in parallel with chronic exposure to Mn and Positron Emission Tomography (PET) studies of in vivo dopamine release, dopamine transporters and dopamine receptors in the striatum. Analysis of metal concentrations in whole blood and brain was obtained and post-mortem analysis of brain tissue was used to confirm the in vivo PET findings. Chronic Mn exposure resulted in subtle motor function deficits that were associated with a marked decrease of in vivo dopamine release in the absence of a change in markers of dopamine (DA) terminal integrity or dopamine receptors in the striatum. These alterations in nigrostriatal DA system function were observed at blood Mn concentrations within the upper range of environmental, medical and occupational exposures in humans. These findings show that Mn-exposed non-human primates that exhibit subtle motor function deficits have an apparently intact but dysfunctional nigrostriatal DA system and provide a novel mechanism of Mn effects on the dopaminergic system.
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Affiliation(s)
- Tomás R Guilarte
- Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
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