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Lee EY, Kim J, Prado-Rico JM, Du G, Lewis MM, Kong L, Yanosky JD, Eslinger P, Kim BG, Hong YS, Mailman RB, Huang X. Effects of mixed metal exposures on MRI diffusion features in the medial temporal lobe. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2023.07.18.23292828. [PMID: 37503124 PMCID: PMC10371112 DOI: 10.1101/2023.07.18.23292828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Background Environmental exposure to metal mixtures is common and may be associated with increased risk for neurodegenerative disorders including Alzheimer's disease. Objective This study examined associations of mixed metal exposures with medial temporal lobe (MTL) MRI structural metrics and neuropsychological performance. Methods Metal exposure history, whole blood metal, and neuropsychological tests were obtained from subjects with/without a history of mixed metal exposure from welding fumes (42 exposed subjects; 31 controls). MTL structures (hippocampus, entorhinal and parahippocampal cortices) were assessed by morphologic (volume, cortical thickness) and diffusion tensor imaging [mean (MD), axial (AD), radial diffusivity (RD), and fractional anisotropy (FA)] metrics. In exposed subjects, correlation, multiple linear, Bayesian kernel machine regression, and mediation analyses were employed to examine effects of single- or mixed-metal predictor(s) and their interactions on MTL structural and neuropsychological metrics; and on the path from metal exposure to neuropsychological consequences. Results Compared to controls, exposed subjects had higher blood Cu, Fe, K, Mn, Pb, Se, and Zn levels (p's<0.026) and poorer performance in processing/psychomotor speed, executive, and visuospatial domains (p's<0.046). Exposed subjects displayed higher MD, AD, and RD in all MTL ROIs (p's<0.040) and lower FA in entorhinal and parahippocampal cortices (p's<0.033), but not morphological differences. Long-term mixed-metal exposure history indirectly predicted lower processing speed performance via lower parahippocampal FA (p=0.023). Higher whole blood Mn and Cu predicted higher entorhinal diffusivity (p's<0.043) and lower Delayed Story Recall performance (p=0.007) without overall metal mixture or interaction effects. Discussion Mixed metal exposure predicted MTL structural and neuropsychological features that are similar to Alzheimer's disease at-risk populations. These data warrant follow-up as they may illuminate the path for environmental exposure to Alzheimer's disease-related health outcomes.
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Affiliation(s)
- Eun-Young Lee
- Department of Health Care and Science, Dong-A University, Busan, South-Korea
| | - Juhee Kim
- Department of Health Care and Science, Dong-A University, Busan, South-Korea
| | - Janina Manzieri Prado-Rico
- Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA
| | - Guangwei Du
- Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA
| | - Mechelle M. Lewis
- Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA
- Department of Pharmacology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA
| | - Lan Kong
- Department of Public Health Sciences, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA
| | - Jeff D. Yanosky
- Department of Public Health Sciences, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA
| | - Paul Eslinger
- Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA
| | - Byoung-Gwon Kim
- Department of Preventive Medicine, College of Medicine, Dong-A University, Busan, South Korea
| | - Young-Seoub Hong
- Department of Preventive Medicine, College of Medicine, Dong-A University, Busan, South Korea
| | - Richard B. Mailman
- Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA
- Department of Pharmacology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA
| | - Xuemei Huang
- Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA
- Department of Pharmacology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA
- Department of Radiology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA
- Department of Neurosurgery, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA
- Department of Kinesiology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA 17033, USA
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Gurol KC, Aschner M, Smith DR, Mukhopadhyay S. Role of excretion in manganese homeostasis and neurotoxicity: a historical perspective. Am J Physiol Gastrointest Liver Physiol 2022; 322:G79-G92. [PMID: 34786983 PMCID: PMC8714252 DOI: 10.1152/ajpgi.00299.2021] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The essential metal manganese (Mn) induces incurable neurotoxicity at elevated levels that manifests as parkinsonism in adults and fine motor and executive function deficits in children. Studies on Mn neurotoxicity have largely focused on the role and mechanisms of disease induced by elevated Mn exposure from occupational or environmental sources. In contrast, the critical role of excretion in regulating Mn homeostasis and neurotoxicity has received less attention although 1) studies on Mn excretion date back to the 1920s; 2) elegant radiotracer Mn excretion assays in the 1940s to 1960s established the routes of Mn excretion; and 3) studies on patients with liver cirrhosis in the 1990s to 2000s identified an association between decreased Mn excretion and the risk of developing Mn-induced parkinsonism in the absence of elevated Mn exposure. Notably, the last few years have seen renewed interest in Mn excretion largely driven by the discovery that hereditary Mn neurotoxicity due to mutations in SLC30A10 or SLC39A14 is caused, at least in part, by deficits in Mn excretion. Quite remarkably, some of the recent results on SLC30A10 and SLC39A14 provide explanations for observations made ∼40-50 years ago. The goal of the current review is to integrate the historic studies on Mn excretion with more contemporary recent work and provide a comprehensive state-of-the-art overview of Mn excretion and its role in regulating Mn homeostasis and neurotoxicity. A related goal is to discuss the significance of some of the foundational studies on Mn excretion so that these highly consequential earlier studies remain influential in the field.
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Affiliation(s)
- Kerem C. Gurol
- 1Division of Pharmacology & Toxicology, College of Pharmacy, and Institute for Neuroscience, The University of Texas at Austin, Austin, Texas
| | - Michael Aschner
- 2Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York
| | - Donald R. Smith
- 3Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California
| | - Somshuvra Mukhopadhyay
- 1Division of Pharmacology & Toxicology, College of Pharmacy, and Institute for Neuroscience, The University of Texas at Austin, Austin, Texas
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3
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Nasr P, Ignatova S, Lundberg P, Kechagias S, Ekstedt M. Low hepatic manganese concentrations in patients with hepatic steatosis - A cohort study of copper, iron and manganese in liver biopsies. J Trace Elem Med Biol 2021; 67:126772. [PMID: 34000573 DOI: 10.1016/j.jtemb.2021.126772] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/27/2021] [Accepted: 05/03/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND AND AIMS Hepatic steatosis is the most common histopathological finding on liver biopsy, with the most prevalent etiology being NAFLD. The pathogenesis of hepatic steatosis and NAFLD is multifactorial, however, studies on the importance of manganese in NAFLD are limited. We aimed to study hepatic manganese content, and other trace elements, in relation to hepatic steatosis in patients with chronic liver diseases of different etiology, mainly NAFLD. METHODS Patients with chronically elevated liver function tests underwent a diagnostic work-up, including routine blood tests and two liver biopsies. One of the biopsies was sent for histopathological evaluation, and the other for ultra-trace elemental determinations. Steatosis was graded using conventional histopathological methodology, and fat content was also quantitated in biopsy samples by measuring the steatotic area of the section using stereological point counting (SPC). Ultra-trace elemental analysis was utilized for determining manganese, iron, and copper using inductively coupled plasma sector field mass spectrometry (ICP-SFMS). RESULTS 76 patients were included in the study. Hepatic manganese concentrations in patients with steatosis were lower than in patients without hepatic steatosis (3.8 ± 1.1 vs. 6.4 ± 1.8, P < 0.001). Similar results were seen for blood manganese levels and hepatic steatosis. We found a strong inverse correlation between steatosis grade and hepatic manganese content (ρ=-0.743, P < 0.001). Also, low levels of manganese independently predicted the presence of steatosis (aOR 0.07 [95%CI: 0.01-0.63]). CONCLUSION Patients with NAFLD, or other CLD and concomitant hepatic steatosis, showed lower levels of hepatic manganese content with increasing grade of steatosis.
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Affiliation(s)
- Patrik Nasr
- Department of Gastroenterology and Hepatology, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.
| | - Simone Ignatova
- Department of Clinical Pathology and Clinical Genetics, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.
| | - Peter Lundberg
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden; Department of Radiation Physics, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.
| | - Stergios Kechagias
- Department of Gastroenterology and Hepatology, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.
| | - Mattias Ekstedt
- Department of Gastroenterology and Hepatology, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden; Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.
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Karanfilian BV, Cheung M, Dellatore P, Park T, Rustgi VK. Laboratory Abnormalities of Hepatic Encephalopathy. Clin Liver Dis 2020; 24:197-208. [PMID: 32245527 DOI: 10.1016/j.cld.2020.01.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Currently, there is no gold standard serologic or imaging modality to detect hepatic encephalopathy (HE). It is a clinical diagnosis gathered from the history and physical. Imaging is nonspecific; however, PET and MRI have shown areas of utility, but are not widely available, cost-efficient, or necessary for diagnosis. Electroencephalogram has shown promise as it can be used in conjunction with the Portal Systemic Hepatic Encephalopathy Score test to diagnose minimal HE. Further research on these techniques would need to be performed to identify strict criteria and cutoffs for diagnosing HE as well as associated sensitivities and specificities.
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Affiliation(s)
- Briette Verken Karanfilian
- Department of Internal Medicine, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ, USA; Department of Medicine, 125 Paterson Street, New Brunswick, NJ 08901, USA
| | - Maggie Cheung
- Department of Internal Medicine, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ, USA; Department of Medicine, 125 Paterson Street, New Brunswick, NJ 08901, USA
| | - Peter Dellatore
- Department of Internal Medicine, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ, USA; Department of Medicine, 125 Paterson Street, New Brunswick, NJ 08901, USA
| | - Taeyang Park
- Department of Internal Medicine, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ, USA; Department of Medicine, 125 Paterson Street, New Brunswick, NJ 08901, USA
| | - Vinod K Rustgi
- Department Gastroenterology and Hepatology, Rutgers-Robert Wood Johnson Medical School, 125 Paterson Street, Suite 5100B, New Brunswick, NJ 08901, USA.
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Sachse B, Kolbaum AE, Ziegenhagen R, Andres S, Berg K, Dusemund B, Hirsch-Ernst KI, Kappenstein O, Müller F, Röhl C, Lindtner O, Lampen A, Schäfer B. Dietary Manganese Exposure in the Adult Population in Germany-What Does it Mean in Relation to Health Risks? Mol Nutr Food Res 2019; 63:e1900065. [PMID: 31216097 DOI: 10.1002/mnfr.201900065] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 04/29/2019] [Indexed: 11/10/2022]
Abstract
Manganese is both an essential nutrient and a potential neurotoxicant. Therefore, the question arises whether the dietary manganese intake in the German population is on the low or high side. Results from a pilot total diet study in Germany presented here reveal that the average dietary manganese intake in the general population in Germany aged 14-80 years is about 2.8 mg day-1 for a person of 70 kg body weight. This exposure level is within the intake range of 2-5 mg per person and day as recommended by the societies for nutrition in Germany, Austria, and Switzerland. No information on the dietary exposure of children in Germany can be provided so far. Although reliable information on health effects related to oral manganese exposure is limited, there is no indication from the literature that these dietary intake levels are associated with adverse health effects either by manganese deficiency or excess. However, there is limited evidence that manganese taken up as a highly bioavailable bolus, for example, uptake via drinking water or food supplements, could pose a potential risk to human health-particularly in certain subpopulations-when certain intake amounts, which are currently not well defined, are exceeded.
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Affiliation(s)
- Benjamin Sachse
- German Federal Institute for Risk Assessment (BfR), Department of Food Safety, 10589, Berlin, Germany
| | - Anna Elena Kolbaum
- German Federal Institute for Risk Assessment (BfR), Department of Exposure, 12277, Berlin, Germany
| | - Rainer Ziegenhagen
- German Federal Institute for Risk Assessment (BfR), Department of Food Safety, 10589, Berlin, Germany
| | - Susanne Andres
- German Federal Institute for Risk Assessment (BfR), Department of Food Safety, 10589, Berlin, Germany
| | - Katharina Berg
- German Federal Institute for Risk Assessment (BfR), Department of Exposure, 12277, Berlin, Germany
| | - Birgit Dusemund
- German Federal Institute for Risk Assessment (BfR), Department of Food Safety, 10589, Berlin, Germany
| | - Karen Ildico Hirsch-Ernst
- German Federal Institute for Risk Assessment (BfR), Department of Food Safety, 10589, Berlin, Germany
| | - Oliver Kappenstein
- German Federal Institute for Risk Assessment (BfR), Department of Chemicals and Product Safety, 10589, Berlin, Germany
| | - Frederic Müller
- German Federal Institute for Risk Assessment (BfR), Department of Chemicals and Product Safety, 10589, Berlin, Germany
| | - Claudia Röhl
- German Federal Institute for Risk Assessment (BfR), Department of Food Safety, 10589, Berlin, Germany.,State Agency for Social Services Schleswig-Holstein (LAsD), Department of Environmental Health Protection, 24105, Kiel, Germany
| | - Oliver Lindtner
- German Federal Institute for Risk Assessment (BfR), Department of Exposure, 12277, Berlin, Germany
| | - Alfonso Lampen
- German Federal Institute for Risk Assessment (BfR), Department of Food Safety, 10589, Berlin, Germany
| | - Bernd Schäfer
- German Federal Institute for Risk Assessment (BfR), Department of Food Safety, 10589, Berlin, Germany
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6
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Abstract
Although an essential nutrient, manganese (Mn) can be toxic at high doses. There is, however, uncertainty regarding the effects of chronic low-level Mn-exposure. This review provides an overview of Mn-related brain and functional changes based on studies of a cohort of asymptomatic welders who had lower Mn-exposure than in most previous work. In welders with low-level Mn-exposure, we found: 1) Mn may accumulate in the brain in a non-linear fashion: MRI R1 (1/T1) signals significantly increased only after a critical level of exposure was reached (e.g., ≥300 welding hours in the past 90days prior to MRI). Moreover, R1 may be a more sensitive marker to capture short-term dynamic changes in Mn accumulation than the pallidal index [T1-weighted intensity ratio of the globus pallidus vs. frontal white matter], a traditional marker for Mn accumulation; 2) Chronic Mn-exposure may lead to microstructural changes as indicated by lower diffusion tensor fractional anisotropy values in the basal ganglia (BG), especially when welding years exceeded more than 30 years; 3) Mn-related subtle motor dysfunctions can be captured sensitively by synergy metrics (indices for movement stability), whereas traditional fine motor tasks failed to detect any significant differences; and 4) Iron (Fe) also may play a role in welding-related neurotoxicity, especially at low-level Mn-exposure, evidenced by higher R2* values (an estimate for brain Fe accumulation) in the BG. Moreover, higher R2* values were associated with lower phonemic fluency performance. These findings may guide future studies and the development of occupation- and public health-related polices involving Mn-exposure.
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7
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Chiapparini L, Pigatto PD, Guzzi G. Low-signal intensity on MRI in the globus pallidus in children with long-term oral manganese exposure. Neurotoxicology 2016; 58:92-93. [PMID: 27899305 DOI: 10.1016/j.neuro.2016.11.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 11/21/2016] [Accepted: 11/25/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Luisa Chiapparini
- Neuroradiology Department, Foundation IRCCS Neurological Institute Carlo Besta, Via Celoria 11, 20133, Milan, Italy; Department of Biomedical, Surgical and Dental Sciences, Unit of Oral Pathology and Medicine, IRCCS Galeazzi Hospital, University of Milan, Milan, Italy; Italian Association for Metals and Biocompatibility Research - A.I.R.M.E.B. (not-for-profit organization), Via A. Banfi 4, 20122, Milan, Italy
| | - Paolo D Pigatto
- Neuroradiology Department, Foundation IRCCS Neurological Institute Carlo Besta, Via Celoria 11, 20133, Milan, Italy; Department of Biomedical, Surgical and Dental Sciences, Unit of Oral Pathology and Medicine, IRCCS Galeazzi Hospital, University of Milan, Milan, Italy; Italian Association for Metals and Biocompatibility Research - A.I.R.M.E.B. (not-for-profit organization), Via A. Banfi 4, 20122, Milan, Italy
| | - Gianpaolo Guzzi
- Neuroradiology Department, Foundation IRCCS Neurological Institute Carlo Besta, Via Celoria 11, 20133, Milan, Italy; Department of Biomedical, Surgical and Dental Sciences, Unit of Oral Pathology and Medicine, IRCCS Galeazzi Hospital, University of Milan, Milan, Italy; Italian Association for Metals and Biocompatibility Research - A.I.R.M.E.B. (not-for-profit organization), Via A. Banfi 4, 20122, Milan, Italy.
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8
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Grover VPB, Southern L, Dyson JK, Kim JU, Crossey MME, Wylezinska‐Arridge M, Patel N, Fitzpatrick JA, Bak‐Bol A, Waldman AD, Alexander GJ, Mells GF, Chapman RW, Jones DEJ, Taylor‐Robinson SD. Early primary biliary cholangitis is characterised by brain abnormalities on cerebral magnetic resonance imaging. Aliment Pharmacol Ther 2016; 44:936-945. [PMID: 27604637 PMCID: PMC5082539 DOI: 10.1111/apt.13797] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 06/09/2016] [Accepted: 08/19/2016] [Indexed: 12/12/2022]
Abstract
BACKGROUND Brain change can occur in primary biliary cholangitis (PBC), potentially as a result of cholestatic and/or inflammatory processes. This change is linked to systemic symptoms of fatigue and cognitive impairment. AIM To identify whether brain change occurs early in PBC. If the change develops early and is progressive, it may explain the difficulty in treating these symptoms. METHODS Early disease brain change was explored in 13 patients with newly diagnosed biopsy-proven precirrhotic PBC using magnetisation transfer, diffusion-weighted imaging and 1 H magnetic resonance spectroscopy. Results were compared to 17 healthy volunteers. RESULTS Cerebral magnetisation transfer ratios were reduced in early PBC, compared to healthy volunteers, in the thalamus, putamen and head of caudate with no greater reduction in patients with greater symptom severity. Mean apparent diffusion coefficients were increased in the thalamus only. No 1 H magnetic resonance spectroscopy abnormalities were seen. Serum manganese levels were elevated in all PBC patients, but no relationship was seen with imaging or symptom parameters. There were no correlations between neuroimaging data, laboratory data, symptom severity scores or age. CONCLUSIONS This is the first study to be performed in this precirrhotic patient population, and we have highlighted that neuroimaging changes are present at a much earlier stage than previously demonstrated. The neuroimaging abnormalities suggest that the brain changes seen in PBC occur early in the pathological process, even before significant liver damage has occurred. If such changes are linked to symptom pathogenesis, this could have important implications for the timing of second-line-therapy use.
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Affiliation(s)
- V. P. B. Grover
- Liver UnitDivision of Diabetes, Endocrinology and MetabolismDepartment of MedicineImperial College LondonLondonUK,Robert Steiner MRI UnitImaging Sciences DepartmentMRC Clinical Sciences CentreImperial College LondonLondonUK
| | - L. Southern
- Liver UnitDivision of Diabetes, Endocrinology and MetabolismDepartment of MedicineImperial College LondonLondonUK
| | - J. K. Dyson
- Institute of Cellular MedicineNewcastle UniversityNewcastle‐upon‐TyneUK
| | - J. U. Kim
- Liver UnitDivision of Diabetes, Endocrinology and MetabolismDepartment of MedicineImperial College LondonLondonUK
| | - M. M. E. Crossey
- Liver UnitDivision of Diabetes, Endocrinology and MetabolismDepartment of MedicineImperial College LondonLondonUK
| | - M. Wylezinska‐Arridge
- Robert Steiner MRI UnitImaging Sciences DepartmentMRC Clinical Sciences CentreImperial College LondonLondonUK
| | - N. Patel
- Robert Steiner MRI UnitImaging Sciences DepartmentMRC Clinical Sciences CentreImperial College LondonLondonUK
| | - J. A. Fitzpatrick
- Liver UnitDivision of Diabetes, Endocrinology and MetabolismDepartment of MedicineImperial College LondonLondonUK,Robert Steiner MRI UnitImaging Sciences DepartmentMRC Clinical Sciences CentreImperial College LondonLondonUK
| | - A. Bak‐Bol
- Liver UnitDivision of Diabetes, Endocrinology and MetabolismDepartment of MedicineImperial College LondonLondonUK
| | - A. D. Waldman
- Robert Steiner MRI UnitImaging Sciences DepartmentMRC Clinical Sciences CentreImperial College LondonLondonUK
| | - G. J. Alexander
- Cambridge Hepatobiliary ServiceAddenbrookes Hospital. Hills RoadCambridgeUK
| | - G. F. Mells
- Cambridge Hepatobiliary ServiceAddenbrookes Hospital. Hills RoadCambridgeUK
| | - R. W Chapman
- Nuffield Department of MedicineOxford UniversityJohn Radcliffe HospitalOxfordUK
| | - D. E. J. Jones
- Institute of Cellular MedicineNewcastle UniversityNewcastle‐upon‐TyneUK
| | - S. D. Taylor‐Robinson
- Liver UnitDivision of Diabetes, Endocrinology and MetabolismDepartment of MedicineImperial College LondonLondonUK
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9
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Lewis MM, Lee EY, Jo HJ, Du G, Park J, Flynn MR, Kong L, Latash ML, Huang X. Synergy as a new and sensitive marker of basal ganglia dysfunction: A study of asymptomatic welders. Neurotoxicology 2016; 56:76-85. [PMID: 27373673 PMCID: PMC5729892 DOI: 10.1016/j.neuro.2016.06.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 06/20/2016] [Accepted: 06/29/2016] [Indexed: 12/29/2022]
Abstract
BACKGROUND Multi-digit synergies, a recently developed, theory-based method to quantify stability of motor action, are shown to reflect basal ganglia dysfunction associated with parkinsonian syndromes. In this study, we tested the hypothesis that multi-digit synergies may capture early and subclinical basal ganglia dysfunction. We chose asymptomatic welders to test the hypothesis because the basal ganglia are known to be most susceptible to neurotoxicity caused by welding-related metal accumulation (such as manganese and iron). METHODS Twenty right-handed welders and 13 matched controls were invited to perform single- and multi-finger pressing tasks using the fingers of the right or left hand. Unified Parkinson's Disease Rating Scale and Grooved Pegboard scores were used to gauge gross and fine motor dysfunction, respectively. High-resolution (3T) T1-weighted, T2-weighted, T1 mapping, susceptibility, and diffusion tensor MRIs were obtained to reflect manganese, iron accumulation, and microstructural changes in basal ganglia. The synergy index stabilizing total force and anticipatory synergy adjustments were computed, compared between groups, and correlated with estimates of basal ganglia manganese [the pallidal index, R1 (1/T1)], iron [R2* (1/T2*)], and microstructural changes [fractional anisotropy and mean diffusivity]. RESULTS There were no significant differences in Unified Parkinson's Disease Rating Scale (total or motor subscale) or Grooved Pegboard test scores between welders and controls. The synergy index during steady-state accurate force production was decreased significantly in the left hand of welders compared to controls (p=0.004) but did not reach statistical significance in the right hand (p=0.16). Anticipatory synergy adjustments, however, were not significantly different between groups. Among welders, higher synergy indices in the left hand were associated significantly with higher fractional anisotropy values in the left globus pallidus (R=0.731, p<0.001) but not with the pallidal index, R1, or R2* values in the basal ganglia. CONCLUSIONS These data suggest that multi-digit synergy metrics may serve as preclinical markers for basal ganglia dysfunction in welders and other populations at risk for neurodegenerative diseases involving parkinsonian symptoms. This finding may have important clinical, scientific, and public/occupational health implications.
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Affiliation(s)
- Mechelle M Lewis
- Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, United States; Department of Pharmacology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, United States
| | - Eun-Young Lee
- Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, United States
| | - Hang Jin Jo
- Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, United States
| | - Guangwei Du
- Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, United States
| | - Jaebum Park
- Institute of Sport Science, Seoul National University, Seoul, South Korea
| | - Michael R Flynn
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, United States
| | - Lan Kong
- Department of Biostatistics, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, United States
| | - Mark L Latash
- Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, United States.
| | - Xuemei Huang
- Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, United States; Department of Pharmacology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, United States; Department of Radiology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, United States; Department of Neurosurgery, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033, United States; Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, United States.
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10
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Kobtan AA, El-Kalla FS, Soliman HH, Zakaria SS, Goda MA. Higher Grades and Repeated Recurrence of Hepatic Encephalopathy May Be Related to High Serum Manganese Levels. Biol Trace Elem Res 2016; 169:153-8. [PMID: 26129828 DOI: 10.1007/s12011-015-0405-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Accepted: 06/09/2015] [Indexed: 01/27/2023]
Abstract
Hepatic encephalopathy is a serious complication of liver failure. Until now, the precise pathophysiologic mechanisms are not fully determined. It has been demonstrated that manganese plays an important role in the pathogenesis of hepatic encephalopathy. Therefore, we studied manganese levels in serum of cirrhotic patients with hepatic encephalopathy in relation to grading and recurrence of hepatic encephalopathy. One hundred persons were enrolled in the study, 80 cirrhotic patients with or without encephalopathy and 20 healthy controls. Hepatic encephalopathy was diagnosed clinically and by laboratory findings. Serum manganese levels were measured in all participants. The grading of hepatic encephalopathy was significantly correlated to the severity of liver dysfunction. The mean serum manganese level was significantly higher in cirrhotic patients than in controls and in cirrhotic patients with encephalopathy than in those without encephalopathy. It was also significantly higher in patients with advanced grading of hepatic encephalopathy. Serum manganese level was positively correlated to number of recurrences of encephalopathy during a 6-month follow-up period. Serum manganese levels were able to predict recurrence of hepatic encephalopathy within 6 months following the episode. Serum manganese levels are positively correlated to the modified Child-Pugh score of cirrhosis as well as grading and number of recurrences of hepatic encephalopathy. Higher manganese levels seem to be related to worsening of the condition, and its measurement may be used as a predictor of repeated recurrences.
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Affiliation(s)
- Abdelrahman A Kobtan
- Tropical Medicine and Infectious Diseases Department, Faculty of Medicine, Tanta University , 1Algeish St., Tanta, Gharbiyah Governorate, 31111, Egypt.
| | - Ferial S El-Kalla
- Tropical Medicine and Infectious Diseases Department, Faculty of Medicine, Tanta University , 1Algeish St., Tanta, Gharbiyah Governorate, 31111, Egypt
| | - Hanan H Soliman
- Tropical Medicine and Infectious Diseases Department, Faculty of Medicine, Tanta University , 1Algeish St., Tanta, Gharbiyah Governorate, 31111, Egypt
| | - Soha S Zakaria
- Biochemistry Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Mohamed A Goda
- Emergency Department, Senbelawein Central Hospital, Egyptian Ministry of Health, Senbelawein, Egypt
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11
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Walter E, Alsaffar S, Livingstone C, Ashley SL. Manganese toxicity in critical care: Case report, literature review and recommendations for practice. J Intensive Care Soc 2015; 17:252-257. [PMID: 28979499 DOI: 10.1177/1751143715622216] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We present the case of a 62-year-old man on the intensive care unit with pancreatitis. Since early in his admission, and for the remainder of his prolonged stay in intensive care, he has received parenteral nutrition for intestinal failure. The whole blood manganese concentration was significantly increased after 2½ months of parenteral nutrition (PN). Three months into his stay, he developed a resting tremor and extra-pyramidal dyskinesia. In the absence of other neurological symptoms, and with no history of essential tremor, Parkinsonism or cerebral signs, hypermanganesaemia was presumed to be the cause. We review manganese metabolism and toxicity in patients who are fed with parenteral nutrition and review the current recommendations and guidelines.
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Affiliation(s)
- Edward Walter
- Department of Intensive Care, Royal Surrey County Hospital, Surrey, UK
| | - Sinan Alsaffar
- Department of Intensive Care, Royal Surrey County Hospital, Surrey, UK
| | - Callum Livingstone
- Clinical Biochemistry Department, Royal Surrey County Hospital, Surrey, UK
| | - Sarah L Ashley
- Department of Nutrition and Dietetics, Royal Surrey County Hospital, Surrey, UK
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12
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Hoet P, Roels HA. Significance and Usefulness of Biomarkers of Exposure to Manganese. MANGANESE IN HEALTH AND DISEASE 2014. [DOI: 10.1039/9781782622383-00355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Manganese (Mn) accomplishes functions essential to maintaining human health, but at the same time this trace element can be toxic at low levels of exposure and accurate estimation of internal exposure is needed. A biomarker of exposure to Mn is meaningful only if there is sufficient knowledge of the toxicokinetics determining its presence in a biological medium (e.g. whole blood, plasma, urine, hair, nail). Moreover, biological monitoring of exposure to Mn is useful only when the biomarker is sufficiently specific and sensitive to distinguish exposed from non-exposed subjects, when it is dose-related to the external exposure (current, recent, or time-integrated), and when it displays reasonable dose–effect/response relationships with the occurrence of adverse effects on the central nervous system, the critical target for Mn exposure. Human investigations in which biomarkers of Mn exposure meet all these criteria are hard to locate. Overall, the available studies report poor or no associations on an individual basis between external (Mn in air or drinking water) and internal (Mn in blood, urine, hair, or nail) Mn exposure indices. This may be to some extent explained by features inherent of the Mn metabolism (homeostatic control), the Mn biomarker's half-life with respect to the exposure window, and the variable nature of external exposure scenarios. Studies particularly dealing with Mn inhalation exposure, different or poorly described methodological approaches, or air sampling strategies may render direct comparison and interpretation of results a tedious task. Nevertheless, several studies report significant dose–effect associations between biomarkers of Mn exposure and subclinical deficits of psychomotor or neuropsychological test performances. Because directly associated with the site of toxic action and providing the magnetic resonance imaging is done no later than three months after Mn exposure ceased, the Mn T1 relaxation time is potentially the better biomarker of Mn exposure in a clinical context (e.g. after long-term parenteral nutrition, chronic liver failure, methcathinone drug abuse). Magnetic resonance imaging is, however, unpractical as a tool for biological monitoring of exposure to Mn in the occupational setting (inhalation) and in the general population (air, drinking water). In conclusion, it would be inappropriate to recommend, on the basis of the currently available evidence, a reliable well-validated biomarker of exposure to Mn, or to establish a health-based threshold value for subclinical neurotoxic effects.
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Affiliation(s)
- Perrine Hoet
- Université catholique de Louvain (UCL), Institut de Recherche Expérimentale et Clinique (IREC), Louvain Centre for Toxicology and Applied Pharmacology (LTAP) Bruxelles Belgium
| | - Harry A. Roels
- Université catholique de Louvain (UCL), Institut de Recherche Expérimentale et Clinique (IREC), Louvain Centre for Toxicology and Applied Pharmacology (LTAP) Bruxelles Belgium
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Racette BA. Manganism in the 21st century: the Hanninen lecture. Neurotoxicology 2014; 45:201-7. [PMID: 24148923 PMCID: PMC3992192 DOI: 10.1016/j.neuro.2013.09.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/27/2013] [Accepted: 09/22/2013] [Indexed: 11/24/2022]
Abstract
Since the original description of the health effects of inhaled occupational manganese (Mn) by Couper in 1837, an extensive literature details the clinical syndrome and pathophysiology of what was thought to be a rare condition. In the last decade, conventional wisdom regarding the clinicopathological effects of Mn has been challenged. Past exposures to Mn were an order of magnitude higher than modern exposures in developed countries; therefore, the clinical syndrome seen in the time of Couper is no longer typical of modern Mn exposed workers. Parkinsonism (rigidity, bradykinesia, rest tremor, and postural instability) is present in 15% of Mn-exposed workers in welding industries, and these parkinsonian signs are associated with reduced health status and quality of life. These parkinsonian signs also overlap considerably with the clinical findings seen in early stages of Parkinson's disease (PD); although, molecular imaging suggests that Mn-exposed workers have dopaminergic dysfunction in a pattern unique from PD. Furthermore, geographic information system studies demonstrate that regions of the US with high industrial Mn emissions have an increased incidence of PD and increased PD associated mortality. This review will contrast historical, descriptive human studies in Mn-exposed subjects with more recent data and will suggest a research agenda for the 21st century.
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Affiliation(s)
- Brad A Racette
- Department of Neurology, Washington University School of Medicine, 660 S. Euclid Avenue, Box 8111, St. Louis, MO 63110, USA; University of the Witwatersrand, School of Public Health, Faculty of Health Sciences, Johannesburg, South Africa.
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Martinez-Finley EJ, Gavin CE, Aschner M, Gunter TE. Manganese neurotoxicity and the role of reactive oxygen species. Free Radic Biol Med 2013; 62:65-75. [PMID: 23395780 PMCID: PMC3713115 DOI: 10.1016/j.freeradbiomed.2013.01.032] [Citation(s) in RCA: 210] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 01/25/2013] [Accepted: 01/28/2013] [Indexed: 12/21/2022]
Abstract
Manganese (Mn) is an essential dietary nutrient, but an excess or accumulation can be toxic. Disease states, such as manganism, are associated with overexposure or accumulation of Mn and are due to the production of reactive oxygen species, free radicals, and toxic metabolites; alteration of mitochondrial function and ATP production; and depletion of cellular antioxidant defense mechanisms. This review focuses on all of the preceding mechanisms and the scientific studies that support them as well as providing an overview of the absorption, distribution, and excretion of Mn and the stability and transport of Mn compounds in the body.
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Affiliation(s)
- Ebany J Martinez-Finley
- Division of Clinical Pharmacology and Pediatric Toxicology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37240, USA; Center in Molecular Toxicology, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | | | - Michael Aschner
- Division of Clinical Pharmacology and Pediatric Toxicology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37240, USA; Center in Molecular Toxicology, Vanderbilt University Medical Center, Nashville, TN 37240, USA; Center for Molecular Neuroscience, Vanderbilt University Medical Center, Nashville, TN 37240, USA; The Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, TN 37240, USA.
| | - Thomas E Gunter
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
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Abstract
Manganese (Mn) is an essential trace metal that is pivotal for normal cell function and metabolism. Its homeostasis is tightly regulated; however, the mechanisms of Mn homeostasis are poorly characterized. While a number of proteins such as the divalent metal transporter 1, the transferrin/transferrin receptor complex, the ZIP family metal transporters ZIP-8 and ZIP-14, the secretory pathway calcium ATPases SPCA1 and SPCA2, ATP13A2, and ferroportin have been suggested to play a role in Mn transport, the degree that each of them contributes to Mn homeostasis has still to be determined. The recent discovery of SLC30A10 as a crucial Mn transporter in humans has shed further light on our understanding of Mn transport across the cell. Although essential, Mn is toxic at high concentrations. Mn neurotoxicity has been attributed to impaired dopaminergic (DAergic), glutamatergic and GABAergic transmission, mitochondrial dysfunction, oxidative stress, and neuroinflammation. As a result of preferential accumulation of Mn in the DAergic cells of the basal ganglia, particularly the globus pallidus, Mn toxicity causes extrapyramidal motor dysfunction. Firstly described as "manganism" in miners during the nineteenth century, this movement disorder resembles Parkinson's disease characterized by hypokinesia and postural instability. To date, a variety of acquired causes of brain Mn accumulation can be distinguished from an autosomal recessively inherited disorder of Mn metabolism caused by mutations in the SLC30A10 gene. Both, acquired and inherited hypermanganesemia, lead to Mn deposition in the basal ganglia associated with pathognomonic magnetic resonance imaging appearances of hyperintense basal ganglia on T1-weighted images. Current treatment strategies for Mn toxicity combine chelation therapy to reduce the body Mn load and iron (Fe) supplementation to reduce Mn binding to proteins that interact with both Mn and Fe. This chapter summarizes our current understanding of Mn homeostasis and the mechanisms of Mn toxicity and highlights the clinical disorders associated with Mn neurotoxicity.
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Affiliation(s)
- Karin Tuschl
- Clinical and Molecular Genetics Unit, UCL Institute of Child Health, London, United Kingdom.
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17
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Perazzo JC, Tallis S, Delfante A, Souto PA, Lemberg A, Eizayaga FX, Romay S. Hepatic encephalopathy: An approach to its multiple pathophysiological features. World J Hepatol 2012; 4:50-65. [PMID: 22489256 PMCID: PMC3321490 DOI: 10.4254/wjh.v4.i3.50] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2011] [Revised: 11/19/2011] [Accepted: 02/24/2012] [Indexed: 02/06/2023] Open
Abstract
Hepatic encephalopathy (HE) is a neuropsychiatric complex syndrome, ranging from subtle behavioral abnormalities to deep coma and death. Hepatic encephalopathy emerges as the major complication of acute or chronic liver failure. Multiplicity of factors are involved in its pathophysiology, such as central and neuromuscular neurotransmission disorder, alterations in sleep patterns and cognition, changes in energy metabolism leading to cell injury, an oxidative/nitrosative state and a neuroinflammatory condition. Moreover, in acute HE, a condition of imminent threat of death is present due to a deleterious astrocyte swelling. In chronic HE, changes in calcium signaling, mitochondrial membrane potential and long term potential expression, N-methyl-D-aspartate-cGMP and peripheral benzodiazepine receptors alterations, and changes in the mRNA and protein expression and redistribution in the cerebral blood flow can be observed. The main molecule indicated as responsible for all these changes in HE is ammonia. There is no doubt that ammonia, a neurotoxic molecule, triggers or at least facilitates most of these changes. Ammonia plasma levels are increased two- to three-fold in patients with mild to moderate cirrhotic HE and up to ten-fold in patients with acute liver failure. Hepatic and inter-organ trafficking of ammonia and its metabolite, glutamine (GLN), lead to hyperammonemic conditions. Removal of hepatic ammonia is a differentiated work that includes the hepatocyte, through the urea cycle, converting ammonia into GLN via glutamine synthetase. Under pathological conditions, such as liver damage or liver blood by-pass, the ammonia plasma level starts to rise and the risk of HE developing is high. Knowledge of the pathophysiology of HE is rapidly expanding and identification of focally localized triggers has led the development of new possibilities for HE to be considered. This editorial will focus on issues where, to the best of our knowledge, more research is needed in order to clarify, at least partially, controversial topics.
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Affiliation(s)
- Juan Carlos Perazzo
- Juan Carlos Perazzo, Silvina Tallis, Amalia Delfante, Pablo Andrés Souto, Abraham Lemberg, Francisco Xavier Eizayaga, Salvador Romay, Laboratory of Portal Hypertension and Hepatic Encephalopathy, Pathophysiology, School of Pharmacy and Biochemistry, University of Buenos Aires, Junin 950, CP 1113, Buenos Aires, Argentina
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Abstract
Manganese-induced parkinsonism has been recognized since 1837. It has been reported primarily in miners, grinders, and smelters since that time. More recently, isolated case reports involving welders have appeared in the medical literature. Manganism can be distinguished from other forms of parkinsonism by clinical presentation with support from laboratory and radiologic findings. The controversy regarding the risk of parkinsonism in welders is reviewed.
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Affiliation(s)
- Brent Furbee
- Indiana Poison Center, Indiana University School of Medicine, B408 Methodist Hospital, Indianapolis, IN 46206, USA.
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Kang JH, Tsai MC, Lin CC, Lin HL, Lin HC. Increased risk of Parkinsonism among patients with cirrhosis: a 7-year follow-up study. Liver Int 2011; 31:685-91. [PMID: 21457440 DOI: 10.1111/j.1478-3231.2010.02432.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND/AIMS Previous studies have suggested that hepatic (toxic-metabolic) encephalopathy, the major complication of cirrhosis, is a neuropsychiatric disorder typically seen in patients with liver dysfunction after exclusion of other known brain disease. This study aims to investigate the risk for parkinsonism during a 7-year follow-up period after a diagnosis of cirrhosis. METHODS In total, 1361 patients with cirrhosis and 6805 comparison patients without cirrhosis were included in this study. Each patient was then individually tracked for 7 years from the time of their initial diagnosis of cirrhosis to identify those who developed parkinsonism during the follow-up period. Stratified Cox proportional hazard regressions were conducted to calculate the hazard of parkinsonism for the two groups during the follow-up period, after adjusting for patient's age, monthly income, level of urbanization and geographic location. RESULTS Of the total 8166 sampled patients, 141 (1.7%) developed parkinsonism during the follow-up period, 48 from the study group (3.5% of the patients with cirrhosis) and 93 from the comparison group (1.4% of patients in the comparison group). Stratified Cox proportional hazard regressions show that the hazard for parkinsonism for patients with cirrhosis was 2.65 times as high (95% confidence interval=1.85-3.80, P<0.001) as the patients in the comparison group over the 7-year follow-up period, after adjusting for patient's age, monthly income, level of urbanization and the geographic location of the community in which the patient resided. CONCLUSIONS We concluded that cirrhosis significantly increased the risk of parkinsonism.
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Affiliation(s)
- Jiunn-Horng Kang
- Neuroscience Research Center, Taipei Medical University Hospital, Taipei, Taiwan
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20
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Effects of manganese on tyrosine hydroxylase (TH) activity and TH-phosphorylation in a dopaminergic neural cell line. Toxicol Appl Pharmacol 2011; 254:65-71. [PMID: 21310168 DOI: 10.1016/j.taap.2010.03.023] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 03/17/2010] [Accepted: 03/17/2010] [Indexed: 11/23/2022]
Abstract
Manganese (Mn) exposure causes manganism, a neurological disorder similar to Parkinson's disease. However, the cellular mechanism by which Mn impairs the dopaminergic neurotransmitter system remains unclear. We previously demonstrated that caspase-3-dependent proteolytic activation of protein kinase C delta (PKCδ) plays a key role in Mn-induced apoptotic cell death in dopaminergic neurons. Recently, we showed that PKCδ negatively regulates tyrosine hydroxylase (TH), the rate-limiting enzyme in dopamine synthesis, by enhancing protein phosphatase-2A activity in dopaminergic neurons. Here, we report that Mn exposure can affect the enzymatic activity of TH, the rate-limiting enzyme in dopamine synthesis, by activating PKCδ-PP2A signaling pathway in a dopaminergic cell model. Low dose Mn (3-10μM) exposure to differentiated mesencephalic dopaminergic neuronal cells for 3h induced a significant increase in TH activity and phosphorylation of TH-Ser40. The PKCδ specific inhibitor rottlerin did not prevent Mn-induced TH activity or TH-Ser40 phosphorylation. On the contrary, chronic exposure to 0.1-1 μM Mn for 24h induced a dose-dependent decrease in TH activity. Interestingly, chronic Mn treatment significantly increased PKCδ kinase activity and protein phosphatase 2A (PP2A) enzyme activity. Treatment with the PKCδ inhibitor rottlerin almost completely prevented chronic Mn-induced reduction in TH activity, as well as increased PP2A activity. Neither acute nor chronic Mn exposures induced any cytotoxic cell death or altered TH protein levels. Collectively, these results demonstrate that low dose Mn exposure impairs TH activity in dopaminergic cells through activation of PKCδ and PP2A activity.
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21
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Fitsanakis VA, Zhang N, Avison MJ, Erikson KM, Gore JC, Aschner M. Changes in dietary iron exacerbate regional brain manganese accumulation as determined by magnetic resonance imaging. Toxicol Sci 2010; 120:146-53. [PMID: 21177776 DOI: 10.1093/toxsci/kfq376] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Manganese (Mn) is an essential metal required for normal homeostasis. Humans chronically exposed to high Mn levels, however, may exhibit psychomotor signs secondary to increased brain Mn. As Mn and iron (Fe) share several cellular membrane transporters, decreased Fe levels resulting from Fe deficiency or anemia lead to increased brain Mn deposition. Conversely, decreased Mn levels are associated with abnormal brain Fe accumulation. To reduce potential Mn toxicity resulting from brain Mn accumulation, we proposed that increased dietary Fe would attenuate brain Mn deposition. To test this hypothesis, three groups of Sprague-Dawley rats were injected weekly (14 weeks) with Mn (3 mg/kg) and fed normal Fe (TX), Fe-supplemented (FeS), or Fe-deficient (FeD) chow. Control (CN) rats received normal dietary Fe and saline injections. Using magnetic resonance imaging, rats were imaged biweekly for 14 weeks to qualitatively monitor brain Mn and Fe accumulation. Both FeS and FeD had greater brain Mn deposition than TX rats. By week 3, R(1) values, which correlate with Mn deposition, were statistically significantly increased (p < 0.05) in brain stem, cerebellum, cortex, midbrain, and striatum compared with CN or TX animals. By week 14, R(1) values for all brain regions in FeS and FeD animals were statistically significantly increased (p < 0.05). By the end of the study, similar results were obtained for R(2) values, a marker of Fe accumulation. These data suggest that Fe supplementation does not effectively protect and may even exacerbate brain Mn accumulation in mammals subchronically exposed to Mn.
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Extrapyramidal signs predict the development of overt hepatic encephalopathy in patients with liver cirrhosis. Eur J Gastroenterol Hepatol 2010; 22:519-25. [PMID: 20010298 DOI: 10.1097/meg.0b013e328333df0f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND/AIMS The long-term evolution of cirrhotic patients with extrapyramidal signs has not yet been studied. We have investigated the influence of extrapyramidal signs on the prognosis, evolution, and quality of life of patients with liver cirrhosis. METHODS Forty-six patients with cirrhosis were followed up and 18 of them were reevaluated, a mean of 45 months later. Cognitive impairment was measured with psychometric tests (Trail-Making Test part A, Grooved-Pegboard, Block-Design, Oral Symbol Digit and Stroop Test). Extrapyramidal signs were evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS). Health-related quality of life was measured using the SF-36 scale and the Chronic Liver Disease Questionnaire. RESULTS Eleven of the 46 patients who were followed up developed overt hepatic encephalopathy (HE) during the follow-up. The presence of extrapyramidal signs was the unique factor that predicted overt HE and patients with basal higher score in the part 3 of the UPDRS developed overt HE more frequently [hazard ratio=1.29; 95% confidence interval (1.04-1.60) P=0.023]. In the 18 reevaluated patients, there was an increase in the score of the UPDRS part 3 after follow-up. There was a worsening in the score values of the block design and the Number Connection Test. In health-related quality of life scales, patients scored better in the area of mental health of the SF-36 scale. Patients with extrapyramidal signs persisted with worse scores in several items of the SF-36 scale and the Chronic Liver Disease Questionnaire. CONCLUSION The presence of extrapyramidal signs in patients with liver cirrhosis predicts the development of overt HE. These signs increased along the follow-up, and remain a bad influence on quality of life.
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Andersen ME, Dorman DC, Clewell HJ, Taylor MD, Nong A. Multi-dose-route, multi-species pharmacokinetic models for manganese and their use in risk assessment. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2010; 73:217-234. [PMID: 20077292 DOI: 10.1080/15287390903340849] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Manganese (Mn) is an essential element that may be toxic in conditions of overexposure. Nearly 10 years ago, some of the authors of this article published a proposed methodology to perform a tissue-dose-based risk assessment and a detailed list of data needs necessary to perform the assessment. Since that time, a substantial body of Mn pharmacokinetic (PK) data has been generated in rats and nonhuman primates, allowing for the construction of physiologically based pharmacokinetic (PBPK) models for Mn. This study reviews the development of the Mn PBPK models, reassesses the previously identified data needs, and details potential uses of these models in risk assessment of Mn. Based upon numerous animal experiments, pharmacokinetic (PK) models have effectively simulated tissue kinetics of Mn from both inhaled and oral Mn intake. PK models achieve this by incorporating homeostatic control processes, saturable tissue binding capacities, and preferential fluxes in various tissue regions. While minor data gaps still exist, the models captured the main dose-dependent characteristics of Mn disposition in rodents and monkeys and provide a structure to parameterize an equivalent PK description in humans. These models are organized to contribute to a tissue-dose based risk assessment of Mn that simultaneously considers ingestion and inhalation kinetics of Mn along with homeostatic control of Mn.
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Affiliation(s)
- Melvin E Andersen
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709-2137, USA
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24
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Are there common biochemical and molecular mechanisms controlling manganism and parkisonism. Neuromolecular Med 2009; 11:281-96. [PMID: 19757210 DOI: 10.1007/s12017-009-8088-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Accepted: 08/25/2009] [Indexed: 02/08/2023]
Abstract
Over the past several decades there has been considerable progress in our basic knowledge as to the mechanisms and factors regulating Mn toxicity. The disorder known as manganism is associated with the preferential accumulation of Mn in the globus pallidus of the basal ganglia which is generally considered to be the major and initial site of injury. Because the area of the CNS comprising the basal ganglia is very complex and dependent on the precise function and balance of several neurotransmitters, it is not surprising that symptoms of manganism often overlap with that of Parkinson's disease. The fact that neurological symptoms and onset of Mn toxicity are quite broad and can vary unpredictably probably reflects specific genetic variance of the physiological and biochemical makeup within the basal ganglia in any individual. Differences in response to Mn overexposure are, thus, likely due to underlying genetic variability which ultimately presents in deviations in both susceptibility as well as the characteristics of the neurological lesions and symptoms expressed. Although chronic exposure to Mn is not the initial causative agent provoking Parkinsonism, there is evidence suggesting that persistent exposure can predispose an individual to acquire dystonic movements associated with Parkinson's disease. As noted in this review, there appears to be common threads between the two disorders, as mutations in the genes, parkin and ATP13A2, associated with early onset of Parkinsonism, may also predispose an individual to develop Mn toxicity. Mutations in both genes appear to effect transport of Mn into the cell. These genetic difference coupled with additional environmental or nutritional factors must also be considered as contributing to the severity and onset of manganism.
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Long LL, Li XR, Huang ZK, Jiang YM, Fu SX, Zheng W. Relationship between changes in brain MRI and (1)H-MRS, severity of chronic liver damage, and recovery after liver transplantation. Exp Biol Med (Maywood) 2009; 234:1075-85. [PMID: 19546351 DOI: 10.3181/0903-rm-118] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Magnetic resonance imaging (MRI) and (1)H magnetic resonance spectroscopy ((1)H-MRS) have been used in clinics for diagnosis of chronic liver diseases. This study was designed to investigate the relationship between MRI/MRS outcomes and the severity of liver damage. Of 50 patients examined, the MRI signal intensity in the globus pallidus as determined by pallidus index (PI) increased as the disease severity (scored by Child Pugh ranking) worsened (r = 0.353, P < 0.05). The changes in PI values were also linearly associated with Mn concentrations in whole blood (MnB) (r = 0.814, P < 0.01). MRS analysis of four major brain metabolites (i.e., Cho, mI, Glx, and NAA) revealed that the ratios of Cho/Cr and mI/Cr in cirrhosis and CHE patients were significantly decreased in comparison to controls (P < 0.05), whereas the ratio of Glx/Cr was significantly increased (P < 0.05). The Child Pugh scores significantly correlated with mI/Cr (-0.484, P < 0.01) and Glx (0.369, P < 0.05), as well as MnB (0.368, P < 0.05), but not with other brain metabolites. Three patients who received a liver transplant experienced normalization of brain metabolites within 3 months of post-transplantation; the MR imaging of Mn in the globus pallidus completely disappeared 5 months after the surgery. Taken together, this clinical study, which combined MRI/MRS analysis, autopsy exam and liver transplant, clearly demonstrates that liver injury-induced brain Mn accumulation can reversibly alter the homeostasis of brain metabolites Cho, mI and Glx. Our data further suggest that liver transplantation can restore normal brain Mn levels.
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Affiliation(s)
- Li-Ling Long
- Department of Radiology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, China
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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] [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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27
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Aissi M, Nifle C, Roussin Bretagne S, Hubert C, Cordoliani YS, Pico F. [Brain MRI associated with chronic hepatic failure and hypermanganism]. Rev Neurol (Paris) 2009; 166:248-52. [PMID: 19497604 DOI: 10.1016/j.neurol.2009.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 04/08/2009] [Accepted: 04/21/2009] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Hypermanganism is primarily linked to inhalation exposure. Several observations of exogenous manganese poisoning have been reported associating neuropsychiatric symptoms, parkinsonian syndrome and hyperintensities of the two pallida on T1 weighted sequences on brain MRI. Recently, similar neurological and radiological signs have been described without exogenous exposure to manganese but in the framework of endogenous poisoning particularly in chronic hepatic failure. CASE REPORT We report the case of a 41-year-old HIV-positive and HVC-positive man who presented psychomotor impairment associated with bipallidal T1 hyperintensities on the brain MRI. The diagnosis of a hypermanganesemia was made on blood samples. We present a literature review on exogenous and endogenous hypermanganesemia and discuss differential diagnosis in the radiological setting of bipallidal T1 hyperintensities. CONCLUSION Bipallidal T1 hyperintensities on brain MRI may suggest hypermanganism even in the clinical setting of a non-specific neurological disorder such as psychomotor impairment.
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Affiliation(s)
- M Aissi
- Service de neurologie, unité neurovasculaire, centre hospitalier de Versailles, hôpital André-Mignot, université de Versailles Saint-Quentin-en-Yvelines, 1, rue Richaud, 78000 Versailles, France
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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] [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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29
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Sitburana O, Ondo WG. Brain magnetic resonance imaging (MRI) in parkinsonian disorders. Parkinsonism Relat Disord 2008; 15:165-74. [PMID: 19059803 DOI: 10.1016/j.parkreldis.2008.04.033] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 04/10/2008] [Accepted: 04/20/2008] [Indexed: 01/06/2023]
Abstract
Magnetic resonance imaging (MRI) is increasingly integrated into neurological diagnostics. In addition to functional MRI, a large number of sequences (T1W, T2W, PD, T2W gradient echo, diffusion-weighted imaging (DWI), and diffusion tensor imaging (DTI)), investigate CNS abnormalities. Objective quantification techniques (T1W voxel-based morphometry) can also discern subtle anatomical differences. Parkinsonian conditions such as Parkinson's disease, multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration and manganese-induced parkinsonism can clinically overlap, yet have very different prognoses and treatments. Relatively little radiographic interest has focused on movement disorders. Nevertheless in the past decade, a variety of findings, often subtle and routinely overlooked, have emerged to help the clinician differentiate these conditions. This review will summarize and discuss MRI findings in parkinsonian conditions. Most data concern either structural abnormalities or the imaging sequelae of abnormal iron deposition, common in some parkinsonian conditions.
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Affiliation(s)
- Oraporn Sitburana
- Neurology Center, Bumrungrad International Hospital, 33 Sukhumvit 3, Bangkok 10110, Thailand.
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30
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Huda A, Gupta R, Rajakumar N, Thomas M. Role of Magnetic Resonance in Understanding the Pathogenesis of Hepatic Encephalopathy. MAGNETIC RESONANCE INSIGHTS 2008; 2:109-122. [PMID: 20890387 PMCID: PMC2947384 DOI: 10.4137/mri.s973] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A spectrum of neuropsychiatric abnormalities caused by portosystemic venous shunting occurs in hepatic encephalopathy (HE) patients with or without liver dysfunction. It is not completely clear how the astrocyte swelling leads to glial-neuronal dysfunction, and how the symptoms are manifested in HE. A major goal of this work is to review the current status of information available from the existing magnetic resonance (MR) modalities including MR imaging (MRI) and MR Spectroscopy (MRS) as well as other modalities in the understanding the pathogenesis of HE. First, we discuss briefly neuron-histopathology, neurotoxins, neuropsychological and neurophysiological tests. A short review on the progress with single-photon emission computed tomography (SPECT) and positron emission tomography (PET) is then presented. In the remaining part of the manuscript, the following topics pertinent to understanding the pathogenesis of HE are discussed: MRI, diffusion tensor imaging (DTI), one-dimensional MRS based single- and multi-voxel based spectroscopic imaging techniques and two-dimensional MRS.
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Affiliation(s)
- A. Huda
- Department of Physics, California State University, Fresno, CA 93740
- Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - R.K. Gupta
- Department of Radiology, Sanjay Gandhi Post-Graduate Institute of Medical Sciences, Lucknow, India
| | - N. Rajakumar
- Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - M.A. Thomas
- Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
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31
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Bouchard M, Mergler D, Baldwin M, Panisset M, Bowler R, Roels HA. Neurobehavioral functioning after cessation of manganese exposure: a follow-up after 14 years. Am J Ind Med 2007; 50:831-40. [PMID: 17096374 DOI: 10.1002/ajim.20407] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Little is known on the long-term course of early manganese (Mn) neurotoxic effects. Mn alloy workers were examined in a follow-up study 14 years after exposure ceased at a Canadian facility. METHODS The same battery of neurofunctional tests used in the initial examination in 1990 was administered to 77 Mn-workers and 81 referents in 2004. RESULTS Manganese-workers had poorer scores compared to referents both in the initial and follow-up examinations for several motor tasks of the Luria Motor Scale. At follow-up, older Mn-workers (>45 years at cessation of exposure) had poorer scores than referents for tests of cognitive flexibility. Cumulated exposure was associated with poorer test scores for certain neuromotor and cognitive tests and on a mood scale. Differences on certain tests observed at initial examination were not present at follow-up. CONCLUSIONS Manganese exposure was associated with persistent deficits for certain neuromotor functions, cognitive flexibility, and adVerse mood states, while recovery occurred for other functions.
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Affiliation(s)
- M Bouchard
- CINBIOSE, Université du Québec à Montréal, Montréal, Canada
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32
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Walsh MP. The global experience with lead in gasoline and the lessons we should apply to the use of MMT. Am J Ind Med 2007; 50:853-60. [PMID: 17567827 DOI: 10.1002/ajim.20483] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
As leaded gasoline is on the verge of being eliminated from all gasoline worldwide another neurotoxin has been put on the market as a lead substitute. Initial concerns regarding the potential adverse health impacts of this additive have emerged and some evidence indicates that its use could damage pollution controls on advance gasoline fueled vehicles. This paper attempts to draw upon the experience with lead in gasoline to see what lessons we should have learned and how these lessons should apply to the use of the new additive, methylcyclopentadienyl manganese tricarbonyl (MMT). Based on the global experience with lead, the question is whether we have sufficient information to conclude that the precautionary principle should apply to the use of MMT; this would require the developer of the additive to demonstrate conclusively that it is safe before it is sold around the world.
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Affiliation(s)
- Michael P Walsh
- International Consultant, 3105 North Dinwiddie Street, Arlington, VA 22207, USA.
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Abstract
Manganese is an essential trace metal that is widely used in industry, particularly in the manufacture of steel. Exposure to high levels of manganese can cause neurotoxicity with the development of a form of parkinsonism known as manganism. It has recently been hypothesized that manganese exposure might also cause or accelerate the development of Parkinson disease (PD). This article is a review of the pathologic studies that have been reported in patients with manganism and in primates experimentally intoxicated with manganese. They demonstrate a consistent pattern characterized by damage to the globus pallidus (particularly the internal segment) with sparing of the substantia nigra pars compacta and the absence of Lewy bodies. This finding contrasts with what is seen in PD, in which there is preferential degeneration of dopamine neurons in the substantia nigra pars compacta coupled with Lewy bodies and preservation of the pallidum. These pathologic findings do not support the notion that manganese causes PD but rather argues that manganese-induced parkinsonism and PD are distinct and separate disease entities.
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Affiliation(s)
- Daniel P Perl
- Department of Pathology, Mount Sinai School of Medicine, New York, NY 10029-6574, USA.
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Grover VPB, Dresner MA, Forton DM, Counsell S, Larkman DJ, Patel N, Thomas HC, Taylor-Robinson SD. Current and future applications of magnetic resonance imaging and spectroscopy of the brain in hepatic encephalopathy. World J Gastroenterol 2006; 12:2969-78. [PMID: 16718775 PMCID: PMC4124369 DOI: 10.3748/wjg.v12.i19.2969] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatic encephalopathy (HE) is a common neuro-psychiatric abnormality, which complicates the course of patients with liver disease and results from hepatocellular failure and/or portosystemic shunting. The manifestations of HE are widely variable and involve a spectrum from mild subclinical disturbance to deep coma. Research interest has focused on the role of circulating gut-derived toxins, particularly ammonia, the development of brain swelling and changes in cerebral neurotransmitter systems that lead to global CNS depression and disordered function. Until recently the direct investigation of cerebral function has been difficult in man. However, new magnetic resonance imaging (MRI) techniques provide a non-invasive means of assessment of changes in brain volume (coregistered MRI) and impaired brain function (fMRI), while proton magnetic resonance spectroscopy (1H MRS) detects changes in brain biochemistry, including direct measurement of cerebral osmolytes, such as myoinositol, glutamate and glutamine which govern processes intrinsic to cellular homeostasis, including the accumulation of intracellular water. The concentrations of these intracellular osmolytes alter with hyperammonaemia. MRS-detected metabolite abnormalities correlate with the severity of neuropsychiatric impairment and since MR spectra return towards normal after treatment, the technique may be of use in objective patient monitoring and in assessing the effectiveness of various treatment regimens.
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Affiliation(s)
- V-P Bob Grover
- Hepatology Section, Division of Medicine A, St Mary's Campus, Faculty of Medicine, Imperial College London, South Wharf Street, London W2 1NY, United Kingdom.
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35
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Ostiguy C, Asselin P, Malo S. The emergence of manganese-related health problems in Quebec: An integrated approach to evaluation, diagnosis, management and control. Neurotoxicology 2006; 27:350-6. [PMID: 16337003 DOI: 10.1016/j.neuro.2005.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Accepted: 11/02/2005] [Indexed: 01/02/2023]
Abstract
This paper describes the strategy developed in Quebec to deal with an emerging problem: manganism in welders. Only two cases of manganism had been reported to the Commission de la santé et de la sécurité du travail (CSST, Workers Compensation Board in Quebec) before 2000. In the fall of 2001, the CSST was informed of a possible cluster of manganism and received 20 compensation claims from one plant. Action was rapidly taken to understand and tackle this emerging problem. Under the leadership of the CSST, a coordinating working group implemented medical and environmental subcommittees involving representatives of the different partners of the prevention network. After a literature review to document the health risks associated with manganese and the lack of some important information, a panel of international experts was formed to try to reach agreement on the parameters to consider in the diagnosis and management of manganism. The CSST compensation management policies would be adjusted accordingly. Simultaneously, all the available industrial hygiene data were analyzed to estimate where and at what levels workers were exposed to manganese. To complete these data, the exposure of workers in more than 50 industrial plants was evaluated and existing control measures were documented. All these data have been presented for a revision of the Quebec permissible exposure limit (PEL). In this integrated approach, the next step targets the formation of neurologists and neuropsychologists for a standardized medical evaluation, to complete workplace evaluation in the high risk sectors, inform workers and employers and recommend control measures where required, based on a revised PEL. Many strategies will be used to inform the prevention network (about 1000 people), employers and employees of the risks of overexposure to manganese and of the measures to control exposure in all the plants where workers are susceptible to be exposed to manganese.
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Affiliation(s)
- Claude Ostiguy
- Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), 505 De Maisonneuve Boulevard West, Montréal, Que., Canada H3A 3C2.
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36
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Abstract
Neuroimaging such as magnetic resonance imaging (MRI), positron emission tomography (PET), and single-photon emission computed tomography (SPECT) have been used in the last decade for investigating the neurotoxicolgy of manganese (Mn). Increased signal intensities on a T1-weighted image may reflect increased Mn deposits (e.g., due to exposure to Mn) but not necessarily manganism. In a biologically based dose-response model, our recent results strongly suggest that signal intensities in T1-weighted MRI reflect a target site dose. However, the threshold of signal intensity associated with clinical symptoms of manganism remains to be solved. Functional neuroimaging such as PET or SPECT examines the integrity of the nigrostriatal dopaminergic system, and thus is very important for the differential diagnosis of manganism. However, neuroimaging research should also aim at developing specific and sensitive parameters for manganism in Mn-exposed individuals.
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Affiliation(s)
- Yangho Kim
- Department of Occupational and Environmental Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, #290-3 Cheonha-Dong, Dong-Ku Ulsan 682-060, South Korea.
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37
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Dorman DC, Struve MF, Wong BA, Dye JA, Robertson ID. Correlation of brain magnetic resonance imaging changes with pallidal manganese concentrations in rhesus monkeys following subchronic manganese inhalation. Toxicol Sci 2006; 92:219-27. [PMID: 16638924 DOI: 10.1093/toxsci/kfj209] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
High-dose manganese exposure is associated with parkinsonism. Because manganese is paramagnetic, its relative distribution within the brain can be examined using magnetic resonance imaging (MRI). Herein, we present the first comprehensive study to use MRI, pallidal index (PI), and T(1) relaxation rate (R1) in concert with chemical analysis to establish a direct association between MRI changes and pallidal manganese concentration in rhesus monkeys following subchronic inhalation of manganese sulfate (MnSO(4)). Monkeys exposed to MnSO(4) at > or = 0.06 mg Mn/m(3) developed increased manganese concentrations in the globus pallidus, putamen, olfactory epithelium, olfactory bulb, and cerebellum. Manganese concentrations within the olfactory system of the MnSO(4)-exposed monkeys demonstrated a decreasing rostral-caudal concentration gradient, a finding consistent with olfactory transport of inhaled manganese. Marked MRI signal hyperintensities were seen within the olfactory bulb and the globus pallidus; however, comparable changes could not be discerned in the intervening tissue. The R1 and PI were correlated with the pallidal manganese concentration. However, increases in white matter manganese concentrations in MnSO(4)-exposed monkeys confounded the PI measurement and may lead to underestimation of pallidal manganese accumulation. Our results indicate that the R1 can be used to estimate regional brain manganese concentrations and may be a reliable biomarker of occupational manganese exposure. To our knowledge, this study is the first to provide evidence of direct olfactory transport of an inhaled metal in a nonhuman primate. Pallidal delivery of manganese, however, likely arises primarily from systemic delivery and not directly from olfactory transport.
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Affiliation(s)
- David C Dorman
- CIIT Centers for Health Research, 6 Davis Drive, Research Triangle Park, NC 27709-2137, USA.
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38
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Fitsanakis VA, Zhang N, Avison MJ, Gore JC, Aschner JL, Aschner M. The use of magnetic resonance imaging (MRI) in the study of manganese neurotoxicity. Neurotoxicology 2006; 27:798-806. [PMID: 16620989 DOI: 10.1016/j.neuro.2006.03.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2005] [Revised: 03/01/2006] [Accepted: 03/02/2006] [Indexed: 12/30/2022]
Abstract
Manganese (Mn), an element found in many foods, is an important and essential nutrient for proper health and maintenance. It is toxic in high doses, however, and exposure to excessive levels can result in the onset of a neurological disorder similar to, but distinct from, Parkinson's disease. Historically, Mn neurotoxicity was most commonly associated with various occupations, such as Mn mining, welding and steel production. More recently, increases in both blood and brain Mn levels have been observed in persons with liver disease or those receiving prolonged parenteral nutrition. Additionally, rodent data suggest that iron deficiency and anemia may be risk factors for Mn neurotoxicity. Clinically, brain Mn accumulation can be monitored in vivo using non-invasive magnetic resonance imaging (MRI) due to the paramagnetic nature of this element. Indeed, MRI has been used in a variety of settings to evaluate the brain Mn deposition in various populations. This review focuses on the use of MRI technology in studies related specifically to Mn neurotoxicity. Thus, we will examine reports using MRI to confirm brain Mn accumulation in human populations, and conclude with data from non-human primate and rodent models of Mn neurotoxicity.
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Affiliation(s)
- Vanessa A Fitsanakis
- Department of Pediatrics, Vanderbilt University Medical Center, 465 21st Avenue South, Nashville, TN 37232, USA
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Fitsanakis VA, Au C, Erikson KM, Aschner M. The effects of manganese on glutamate, dopamine and gamma-aminobutyric acid regulation. Neurochem Int 2006; 48:426-33. [PMID: 16513220 DOI: 10.1016/j.neuint.2005.10.012] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Accepted: 10/13/2005] [Indexed: 10/25/2022]
Abstract
Exposure to high levels of manganese (Mn) results in a neurological disorder, termed manganism, which shares a similar phenotype to Parkinson's disease due to the involvement of the basal ganglia circuitry in both. The initial symptoms of manganism are likely due to the involvement of the globus pallidus, a region rich in gamma-aminobutyric acid (GABA) projections, while those of Parkinson's disease are related to the degeneration of the substantia nigra, a dopaminergic nucleus. Additionally, it is known that glutamate regulation is affected by increases in brain Mn levels. As Mn predominantly accumulates in the basal ganglia, it potentially could affect the regulation and interactions of all three neurotransmitters. This review will focus on the circuitry of these neurotransmitters within the basal ganglia and address potential sites for, as well as the temporal relationship, between Mn exposure and changes in the levels of these neurotransmitters. While most research has focused on perturbations in the dopaminergic system, there is evidence to support that early consequences of manganism also include disturbances in GABA regulation as well as glutamatergic-related excitotoxicity. Finally, we suggest that current research focus on the interdependence of these basal ganglial neurochemicals, with a greater emphasis on the GABAergic and glutamatergic systems.
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Affiliation(s)
- Vanessa A Fitsanakis
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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Binesh N, Huda A, Thomas MA, Wyckoff N, Bugbee M, Han S, Rasgon N, Davanzo P, Sayre J, Guze B, Martin P, Fawzy F. Hepatic encephalopathy: a neurochemical, neuroanatomical, and neuropsychological study. J Appl Clin Med Phys 2006; 7:86-96. [PMID: 16518320 PMCID: PMC5722484 DOI: 10.1120/jacmp.v7i1.2151] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2005] [Accepted: 08/19/2005] [Indexed: 11/23/2022] Open
Abstract
Hepatic encephalopathy (HE) is normally diagnosed by neuropsychological (NP) tests, which are not very specific and do not reveal the underlying pathology. Magnetic resonance imaging (MRI) and spectroscopy (MRS) of the brain offer alternative and possibly more specific markers for HE. These methods were applied in conjunction with NP testing in order to determine their usefulness in the identification of HE and to understand the pathogenesis of HE more clearly. MR imaging and spectroscopy examinations, in addition to a battery of 15 NP tests, were administered to investigate 31 patients awaiting liver transplantation and 23 healthy controls. MR image intensities from the globus pallidus region were calculated and normalized to those of the thalamus. Absolute concentrations and ratios with respect to creatine (Cr) of several metabolites were computed from MR spectra. The MR data were correlated with the results of NP tests. The patients showed impairment in NP tests of attention and visuospatial and verbal fluency. In T1-weighted MRI, the relative intensity of the globus pallidus with respect to that of the thalamus region was significantly elevated in patients and correlated(negatively) with three NP tests (Hooper, FAS, and Trails B). The absolute concentrations of myo-inositol (mI) and choline (Ch) were significantly reduced in three brain regions. In addition, the absolute concentrations of glutamine (Gln) and combined glutamate and glutamine (Glx) were increased in all three locations, with Gln increase being significant in all areas while that of Glx only in the occipital white matter. In summary, this study partially confirms a hypothesized mechanism of HE pathogenesis, an increased synthesis of glutamine by brain glutamate in astrocytes due to excessive blood ammonia, followed by a compensatory loss of myo-inositol to maintain astrocyte volume homeostasis. It also indicates that the hyperintensity observed in globus pallidus could be used as complementary to the NP test scores in evaluating the mental health of HE patients.
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Affiliation(s)
- Nader Binesh
- Departments of Radiological SciencesUniversity of CaliforniaLos AngelesCalifornia90095
| | - Amir Huda
- Departments of Radiological SciencesUniversity of CaliforniaLos AngelesCalifornia90095
- Department of PhysicsCalifornia State UniversityFresnoCalifornia93740U.S.A.
| | - M. Albert Thomas
- Departments of Radiological SciencesUniversity of CaliforniaLos AngelesCalifornia90095
- Departments of PsychiatryUniversity of CaliforniaLos AngelesCalifornia90095
| | - Nathaniel Wyckoff
- Departments of Radiological SciencesUniversity of CaliforniaLos AngelesCalifornia90095
| | - Mary Bugbee
- Departments of Radiological SciencesUniversity of CaliforniaLos AngelesCalifornia90095
| | - Steven Han
- Departments of HepatologyUniversity of CaliforniaLos AngelesCalifornia90095
| | - Natalie Rasgon
- Departments of PsychiatryUniversity of CaliforniaLos AngelesCalifornia90095
| | - Pablo Davanzo
- Departments of PsychiatryUniversity of CaliforniaLos AngelesCalifornia90095
| | - James Sayre
- Departments of Radiological SciencesUniversity of CaliforniaLos AngelesCalifornia90095
| | - Barry Guze
- Departments of PsychiatryUniversity of CaliforniaLos AngelesCalifornia90095
| | - Paul Martin
- Departments of HepatologyUniversity of CaliforniaLos AngelesCalifornia90095
| | - Fawzy Fawzy
- Departments of PsychiatryUniversity of CaliforniaLos AngelesCalifornia90095
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Abstract
Manganese is an essential mineral that is found at low levels in virtually all diets. Manganese ingestion represents the principal route of human exposure, although inhalation also occurs, predominantly in occupational cohorts. Regardless of intake, animals generally maintain stable tissue manganese levels as a result of homeostatic mechanisms that tightly regulate the absorption and excretion of this metal. However, high-dose exposures are associated with increased tissue manganese levels, causing adverse neurological, reproductive and respiratory effects. In humans, manganese-induced neurotoxicity is associated with a motor dysfunction syndrome, commonly referred to as manganism or Parkinsonism, which is of paramount concern and is considered to be one of the most sensitive endpoints. This article focuses on the dosimetry of manganese with special focus on transport mechanisms of manganese into the CNS. It is not intended to be an exhaustive review of the manganese literature; rather it aims to provide a useful synopsis of contemporary studies from which the reader may progress to other research citations as desired. Specific emphasis is directed towards recent published literature on manganese transporters' systemic distribution of manganese upon inhalation exposure as well as the utility of magnetic resonance imaging in quantifying brain manganese distribution.
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Affiliation(s)
- Michael Aschner
- Department of Pediatrics, Pharmacology, and the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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42
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Elsner RJF, Spangler JG. Neurotoxicity of inhaled manganese: public health danger in the shower? Med Hypotheses 2005; 65:607-16. [PMID: 15913899 DOI: 10.1016/j.mehy.2005.01.043] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Accepted: 01/26/2005] [Indexed: 10/25/2022]
Abstract
CONTEXT Manganese (Mn) is an essential trace element but is neurotoxic at high doses. Showering with Mn-laden water has never been evaluated as a central nervous system (CNS) delivery vector for Mn, even though intranasally administered Mn in laboratory animals circumvents the blood-brain barrier and passes directly into the brain via olfactory pathways. OBJECTIVE To review the literature on Mn and attempt to quantify potential human CNS exposure to manganese from showering. DATA SOURCES We systematically searched Medline 11/9/02 and again on 3/9/04. The following search terms were used: manganese, water, drinking water, shower, showering, bath, bathing and inhalation, then combined with "water or drinking water or showering or shower or bathing or inhalation." STUDY SELECTION Animal experimental investigations, human epidemiological studies, and consensus and governmental reports were utilized. DATA EXTRACTION Data were extracted by both authors and extrapolations to humans were calculated by one of us (JGS) controlling for age, length of exposure and known respiratory differences between rats and humans. DATA SYNTHESIS During a decade of showering in Mn-contaminated water, models for children and adults show higher doses of aerosolized Mn (3-fold and 112-fold greater, respectively) than doses reported to cause Mn brain deposition in rats. CONCLUSIONS Long-term shower exposure to Mn-laden water may pose a significant risk for CNS neurotoxicity via olfactory uptake in up to 8.7 million Americans. If our results are confirmed, regulatory agencies must rethink existing Mn drinking water standards.
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Affiliation(s)
- Robert J F Elsner
- Wake Forest University School of Medicine, Department of Family and Community Medicine, Medical Center Blvd., Winston-Salem, NC 27157-1084, USA
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43
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Abstract
Research into the causes of Parkinson disease (PD) has accelerated recently with the discovery of novel gene mutations. The majority of PD cases, however, remain idiopathic and in those cases environmental causes should be considered. Several recent reports have focused on welding and manganese toxicity as potential risk factors for parkinsonism and some have even proposed that welding is a risk factor for PD. The controversy has stimulated this review, the primary aim of which is to critically and objectively examine the evidence or lack of evidence for a relationship among welding, manganese, parkinsonism, and PD.
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Affiliation(s)
- Joseph Jankovic
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA.
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Aschner M, Erikson KM, Dorman DC. Manganese dosimetry: species differences and implications for neurotoxicity. Crit Rev Toxicol 2005; 35:1-32. [PMID: 15742901 DOI: 10.1080/10408440590905920] [Citation(s) in RCA: 223] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Manganese (Mn) is an essential mineral that is found at low levels in food, water, and the air. Under certain high-dose exposure conditions, elevations in tissue manganese levels can occur. Excessive manganese accumulation can result in adverse neurological, reproductive, and respiratory effects in both laboratory animals and humans. In humans, manganese-induced neurotoxicity (manganism) is the overriding concern since affected individuals develop a motor dysfunction syndrome that is recognized as a form of parkinsonism. This review primarily focuses on the essentiality and toxicity of manganese and considers contemporary studies evaluating manganese dosimetry and its transport across the blood-brain barrier, and its distribution within the central nervous system (CNS). These studies have dramatically improved our understanding of the health risks posed by manganese by determining exposure conditions that lead to increased concentrations of this metal within the CNS and other target organs. Most individuals are exposed to manganese by the oral and inhalation routes of exposure; however, parenteral injection and other routes of exposure are important. Interactions between manganese and iron and other divalent elements occur and impact the toxicokinetics of manganese, especially following oral exposure. The oxidation state and solubility of manganese also influence the absorption, distribution, metabolism, and elimination of manganese. Manganese disposition is influenced by the route of exposure. Rodent inhalation studies have shown that manganese deposited within the nose can undergo direct transport to the brain along the olfactory nerve. Species differences in manganese toxicokinetics and response are recognized with nonhuman primates replicating CNS effects observed in humans while rodents do not. Potentially susceptible populations, such as fetuses, neonates, individuals with compromised hepatic function, individuals with suboptimal manganese or iron intake, and those with other medical states (e.g., pre-parkinsonian state, aging), may have altered manganese metabolism and could be at greater risk for manganese toxicity.
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Latchoumycandane C, Anantharam V, Kitazawa M, Yang Y, Kanthasamy A, Kanthasamy AG. Protein Kinase Cδ Is a Key Downstream Mediator of Manganese-Induced Apoptosis in Dopaminergic Neuronal Cells. J Pharmacol Exp Ther 2004; 313:46-55. [PMID: 15608081 DOI: 10.1124/jpet.104.078469] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Manganese (Mn) exposure causes manganism, a neurological disorder similar to Parkinson's disease. However, the cellular mechanism by which Mn induces dopaminergic neuronal cell death remains unclear. In the present study, we sought to investigate the key downstream apoptotic cell signaling events that contribute to Mn-induced cell death in mesencephalic dopaminergic neuronal (N27) cells. Mn exposure induced a dose-dependent increase in neuronal cell death in N27 cells. The cell death was accompanied by sequential activation of mitochondrial-dependent proapoptotic events, including cytochrome c release, caspase-3 activation, and DNA fragmentation, but not caspase-8 activation, indicating that the mitochondrial-dependent apoptotic cascade primarily triggers Mn-induced apoptosis. Notably, Mn treatment proteolytically activated protein kinase Cdelta (PKCdelta), a member of a novel class of protein kinase C. The caspase-3 specific inhibitor benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethylketone (Z-DEVD-FMK) significantly blocked PKCdelta cleavage and its kinase activity, indicating that caspase-3 mediates the proteolytic activation. Cotreatment with the PKCdelta inhibitor rottlerin or the caspase-3 inhibitor Z-DEVD-FMK almost completely blocked Mn-induced DNA fragmentation. Additionally, N27 cells expressing a catalytically inactive PKCdelta(K376R) protein (PKCdelta dominant negative mutant) or a caspase cleavage resistant PKCdelta(D327A) protein (PKCdelta cleavage resistant mutant) were found to be resistant to Mn-induced apoptosis. To further establish the proapoptotic role of PKCdelta, RNA interference-mediated gene knockdown was performed. Small interfering RNA suppression of PKCdelta expression protected N27 cells from Mn-induced apoptotic cell death. Collectively, these results suggest that caspase-3-dependent proteolytic activation of PKCdelta plays a key role in Mn-induced apoptotic cell death.
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Affiliation(s)
- Calivarathan Latchoumycandane
- Parkinson's Disorder Research Laboratory, Department of Biomedical Sciences, 2008 Veterinary Medicine Bldg., Iowa State University, Ames, IA 50011-1250, USA
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Abstract
It has long been appreciated that manganese exposure can cause neurotoxicity and a neurologic syndrome that resembles Parkinson's disease (PD). Current evidence indicates that manganese-induced parkinsonism can be differentiated from PD because of its predilection to accumulate in and damage the pallidum and striatum rather than the SNc. The clinical syndrome, response to levodopa, imaging studies with MRI and PET, and pathologic features all help to distinguish these two conditions and permit the correct diagnosis to be established. This is of particular relevance in differentiating patients with parkinsonism due to manganese intoxication from patients with idiopathic PD who have incidental manganese exposure.
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Affiliation(s)
- C W Olanow
- Department of Neurology, Mount Sinai School of Medicine, New York, New York 10029, USA.
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Park NH, Park JK, Choi Y, Yoo CI, Lee CR, Lee H, Kim HK, Kim SR, Jeong TH, Park J, Yoon CS, Kim Y. Whole blood manganese correlates with high signal intensities on T1-weighted MRI in patients with liver cirrhosis. Neurotoxicology 2004; 24:909-15. [PMID: 14637385 DOI: 10.1016/s0161-813x(03)00111-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We examined whole blood (MnB), plasma (MnP) and urinary Mn (MnU) concentrations in 33 cirrhotics and 11 healthy controls to clarify: (1) whether, in chronic liver diseases, MnB or MnP reflects pallidal signal intensities in magnetic resonance imaging (MRI); and (2) which factors in chronic liver diseases correlate with pallidal signal intensities in T1-weighted MRI. Increased signal intensity in the pallidum was observed in 27 (81.8%) of 33 patients with liver cirrhosis in T1-weighted MRI. There was a significant correlation between MnB and pallidal index (PI) (gamma = 0.559, P < 0.01) in the patients. However, no significant correlation was observed between MnP and PI (gamma = 0.353, P > 0.05). According to a multiple linear regression, MnB reflected the signal intensities of T1-weighted MRI better than MnP or MnU. Child/Pugh score and total bilirubin level also correlated with PI. However, the hemoglobin level did not correlate with PI significantly.
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Affiliation(s)
- Neung Hwa Park
- Department of Internal Medicine, Ulsan University Hospital, #290-3 Cheonha-Dong, Dong-Ku, Ulsan 682-060, South Korea
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Roth JA, Garrick MD. Iron interactions and other biological reactions mediating the physiological and toxic actions of manganese. Biochem Pharmacol 2003; 66:1-13. [PMID: 12818360 DOI: 10.1016/s0006-2952(03)00145-x] [Citation(s) in RCA: 158] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Chronic exposure to the divalent heavy metals, such as iron, lead, manganese (Mn), and chromium, has been linked to the development of severe, often irreversible neurological disorders and increased vulnerability to developing Parkinson's disease. Although the mechanisms by which these metals elicit or facilitate neuronal cell death are not well defined, neurotoxicity is limited by the extent to which they are transported across the blood-brain barrier and their subsequent uptake within targeted neurons. Once inside the neuron, these heavy metals provoke a series of biochemical and molecular events leading to cell death induced by either apoptosis and/or necrosis. The toxicological properties of Mn have been studied extensively in recent years because of the potential health risk created by increased atmospheric levels owing to the impending use of the gas additive methylcyclopentadienyl manganese tricarbonyl. Individuals exposed to high environmental levels of Mn, which include miners, welders, and those living near ferroalloy processing plants, display a syndrome known as manganism, best characterized by debilitating symptoms resembling those of Parkinson's disease. Mn disposition in vivo is influenced by dietary iron intake and stores within the body since the two metals compete for the same binding protein in serum (transferrin) and subsequent transport systems (divalent metal transporter, DMT1). There appear to be two distinct carrier-mediated transport systems for Mn and ferrous ion: a transferrin-dependent and a transferrin-independent pathway, both of which utilize DMT1 as the transport protein. Accordingly, this commentary focuses on the biochemical and molecular processes responsible for the cytotoxic actions of Mn and the role that cellular transport plays in mediating the physiological as well as the toxicological actions of this metal.
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Affiliation(s)
- Jerome A Roth
- Department of Pharmacology and Toxicology, 102 Farber Hall, University at Buffalo, Buffalo, NY 14214, USA.
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Montes S, Alcaraz-Zubeldia M, Muriel P, Rios C. Role of manganese accumulation in increased brain glutamine of the cirrhotic rat. Neurochem Res 2003; 28:911-7. [PMID: 12718445 DOI: 10.1023/a:1023279527545] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cirrhosis promotes increases of both manganese and glutamine in brain. Manganese is a modulator and glutamine is the product of glutamine synthetase. This work studies the relationship between manganese and glutamine synthetase in a model of cirrhosis in the rat. We administered manganese (1 g/L) in the drinking water of sham-operated and bile-duct obstructed rats. We evaluated the manganese and glutamine accumulation and the glutamine synthetase activity in frontal cortex, striatum, and pallidum after 2, 4, and 6 weeks of biliary obstruction or sham surgery. Cirrhotic rats receiving manganese increased their brain content of metal about 400%-600% after 4 weeks of treatment (P < .05) and also remarkably accumulated glutamine through time in the three regions studied (P < .05 at week 6). Interestingly, bile-duct obstructed rats treated with manganese showed no effect on glutamine synthetase activity. Results from this study suggest that manganese induces increases of brain glutamine independently of its synthesis.
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Affiliation(s)
- Sergio Montes
- Departamento de Neuroquímica, Instituto Nacional de Neurología y, Neurocirugía "Manuel Velasco Suárez", Mexico
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Sassine MP, Mergler D, Bowler R, Hudnell HK. Manganese accentuates adverse mental health effects associated with alcohol use disorders. Biol Psychiatry 2002; 51:909-21. [PMID: 12022965 DOI: 10.1016/s0006-3223(01)01350-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
BACKGROUND A population-based study on early neurotoxic effects of environmental exposure to manganese (Mn) enabled us to investigate the relation between blood Mn levels (MnB), alcohol consumption, and risk for alcohol use disorders (AUD) on mental health. METHODS Participants were selected using a random stratified sampling procedure. Self-administered questionnaires provided data on alcohol consumption, sociodemographics, medical history, and lifestyle. Mood states were assessed with the Brief Symptom Inventory (BSI), and risk for AUD was surveyed using a behavioral screening questionnaire and categorized into no, low, and high risk. Of 297 participants, 253 current drinkers who had responded to all questions on alcohol use were retained. RESULTS Psychologic distress increased with risk for AUD and alcohol consumption > or = 420 g/week. Higher MnB levels (> or =7.5 microg/L) intensified the relation between risk for AUD and BSI scale scores. The Prevalence odd ratios for positive cases of psychologic distress with risk for AUD, 1.98 [1.13-3.46], differed when divided by MnB strata: lower MnB: 1.34 [0.64-2.85]; higher MnB: 4.22 [1.65-10.77]. CONCLUSIONS These findings suggest that higher levels of blood manganese significantly increase neuropsychiatric symptoms associated with risk for alcohol use disorders.
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