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Mittal L, Perry CS, Blanchette AD, Proctor DM. Probabilistic risk assessment of residential exposure to electric arc furnace steel slag using Bayesian model of relative bioavailability and PBPK modeling of manganese. Risk Anal 2024. [PMID: 38622492 DOI: 10.1111/risa.14309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 01/17/2024] [Accepted: 02/14/2024] [Indexed: 04/17/2024]
Abstract
Electric arc furnace (EAF) slag is a coproduct of steel production used primarily for construction purposes. Some applications of EAF slag result in residential exposures by incidental ingestion and inhalation of airborne dust. To evaluate potential health risks, an EAF slag characterization program was conducted to measure concentrations of metals and leaching potential (including oral bioaccessibility) in 38 EAF slag samples. Arsenic, hexavalent chromium, iron, vanadium, and manganese (Mn) were identified as constituents of interest (COIs). Using a probabilistic risk assessment (PRA) approach, estimated distributions of dose for COIs were assessed, and increased cancer risks and noncancer hazard quotients (HQs) at the 50th and 95th percentiles were calculated. For the residents near slag-covered roads, cancer risk and noncancer HQs were <1E - 6 and 1, respectively. For residential driveway or landscape exposure, at the 95th percentile, cancer risks were 1E - 6 and 7E - 07 based on oral exposure to arsenic and hexavalent chromium, respectively. HQs ranged from 0.07 to 2 with the upper bound due to ingestion of Mn among children. To expand the analysis, a previously published physiologically based pharmacokinetic (PBPK) model was used to estimate Mn levels in the globus pallidus for both exposure scenarios and further evaluate the potential for Mn neurotoxicity. The PBPK model estimated slightly increased Mn in the globus pallidus at the 95th percentile of exposure, but concentrations did not exceed no-observed-adverse-effect levels for neurological effects. Overall, the assessment found that the application of EAF slag in residential areas is unlikely to pose a health hazard or increased cancer risk.
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Perry CS, Blanchette AD, Vivanco SN, Verwiel AH, Proctor DM. Use of physiologically based pharmacokinetic modeling to support development of an acute (24-hour) health-based inhalation guideline for manganese. Regul Toxicol Pharmacol 2023; 145:105518. [PMID: 37863417 DOI: 10.1016/j.yrtph.2023.105518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 10/04/2023] [Accepted: 10/18/2023] [Indexed: 10/22/2023]
Abstract
The toxicokinetics of manganese (Mn) are controlled through homeostasis because Mn is an essential element. However, at elevated doses, Mn is also neurotoxic and has been associated with respiratory, reproductive, and developmental effects. While health-based criteria have been developed for chronic inhalation exposure to ambient Mn, guidelines for short-term (24-h) environmental exposure are also needed. We reviewed US state, federal, and international health-based inhalation toxicity criteria, and conducted a literature search of recent publications. The studies deemed most appropriate to derive a 24-h guideline have a LOAEL of 1500 μg/m3 for inflammatory airway changes and biochemical measures of oxidative stress in the brain following 90 total hours of exposure in monkeys. We applied a cumulative uncertainty factor of 300 to this point of departure, resulting in a 24-h guideline of 5 μg/m3. To address uncertainty regarding potential neurotoxicity, we used a previously published physiologically based pharmacokinetic model for Mn to predict levels of Mn in the brain target tissue (i.e., globus pallidus) for exposure at 5 μg/m3 for two short-term human exposure scenarios. The PBPK model predictions support a short-term guideline of 5 μg/m3 as protective of both respiratory effects and neurotoxicity, including exposures of infants and children.
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Affiliation(s)
- Camarie S Perry
- ToxStrategies, 9390 Research Blvd, Bldg. II, Suite 100, Austin, TX, 78759, USA.
| | | | | | - Ann H Verwiel
- ToxStrategies, 1010 B Street, Suite 208, San Rafael, CA, 94901, USA.
| | - Deborah M Proctor
- ToxStrategies, 27001 La Paz Road, Suite 260, Mission Viejo, CA, 92691, USA.
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Brown JS, Diamond GL. Derivation of first-order dissolution rates to estimate particle clearance and burden in the human respiratory tract. Part Fibre Toxicol 2023; 20:17. [PMID: 37106371 PMCID: PMC10134572 DOI: 10.1186/s12989-023-00523-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 04/04/2023] [Indexed: 04/29/2023] Open
Abstract
Inhalation is a portal-of-entry for aerosols via the respiratory tract where particulate burden accumulates depending on sites of particle deposition, normal clearance mechanisms, and particle solubility. The time available for dissolution of particles is determined by the balance between the rate of particle clearance from a region and their solubility in respiratory solvents. Dissolution is a function of particle surface area divided by particle volume or mass (i.e., dissolution is inversely proportional to the physical diameter of particles). As a conservative approach, investigators commonly assume the complete and instantaneous dissolution of metals from particles depositing in the alveolar region of the respiratory tract. We derived first-order dissolution rate constants to facilitate biokinetic modeling of particle clearance, dissolution, and absorption into the blood. We then modeled pulmonary burden and total dissolution of particles over time as a function of particle size, density, and solubility. We show that assuming poorly soluble particle forms will enter the blood as quickly as highly soluble forms causes an overestimation of concentrations of the compound of interest in blood and other extrapulmonary tissues while also underestimating its pulmonary burden. We conclude that, in addition to modeling dose rates for particle deposition into the lung, physiologically based pharmacokinetic modeling of pulmonary and extrapulmonary tissues concentrations of moderately and poorly soluble materials can be improved by including estimates of lung burden and particle dissolution over time.
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Affiliation(s)
- James S Brown
- U.S. Environmental Protection Agency, Office of Research and Development, 109 TW Alexander Drive, Mail Code B243-01, Research Triangle Park, NC, 27711, USA.
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Campbell JL, Clewell HJ, Van Landingham C, Gentry PR, Keene AM, Taylor MD, Andersen ME. Incorporation of rapid association/dissociation processes in tissues into the monkey and human physiologically based pharmacokinetic models for manganese. Toxicol Sci 2022; 191:212-226. [PMID: 36453847 PMCID: PMC9936208 DOI: 10.1093/toxsci/kfac123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
In earlier physiologically based pharmacokinetic (PBPK) models for manganese (Mn), the kinetics of transport of Mn into and out of tissues were primarily driven by slow rates of association and dissociation of Mn with tissue binding sites. However, Mn is known to show rapidly reversible binding in tissues. An updated Mn model for primates, following similar work with rats, was developed that included rapid association/dissociation processes with tissue Mn-binding sites, accumulation of free Mn in tissues after saturation of these Mn-binding sites and rapid rates of entry into tissues. This alternative structure successfully described Mn kinetics in tissues in monkeys exposed to Mn via various routes including oral, inhalation, and intraperitoneal, subcutaneous, or intravenous injection and whole-body kinetics and tissue levels in humans. An important contribution of this effort is showing that the extension of the rate constants for binding and cellular uptake established in the monkey were also able to describe kinetic data from humans. With a consistent model structure for monkeys and humans, there is less need to rely on cadaver data and whole-body tracer studies alone to calibrate a human model. The increased biological relevance of the Mn model structure and parameters provides greater confidence in applying the Mn PBPK models to risk assessment. This model is also well-suited to explicitly incorporate emerging information on the role of transporters in tissue disposition, intestinal uptake, and hepatobiliary excretion of Mn.
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Affiliation(s)
- Jerry L Campbell
- To whom correspondence should be addressed at Ramboll US Corporation, 3214 Charles B. Root Wynd, Suite 130, Raleigh, NC 27612, USA. E-mail:
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Jensen N, Terrell R, Ramoju S, Shilnikova N, Farhat N, Karyakina N, Cline BH, Momoli F, Mattison D, Krewski D. Magnetic resonance imaging T1 indices of the brain as biomarkers of inhaled manganese exposure. Crit Rev Toxicol 2022; 52:358-370. [PMID: 36412542 DOI: 10.1080/10408444.2022.2128719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Excessive exposure to manganese (Mn) is linked to its accumulation in the brain and adverse neurological effects. Paramagnetic properties of Mn allow the use of magnetic resonance imaging (MRI) techniques to identify it in biological tissues. A critical review was conducted to evaluate whether MRI techniques could be used as a diagnostic tool to detect brain Mn accumulation as a quantitative biomarker of inhaled exposure. A comprehensive search was conducted in MEDLINE, EMBASE, and PubMed to identify potentially relevant studies published prior to 9 May 2022. Two reviewers independently screened identified references using a two-stage process. Of the 6452 unique references identified, 36 articles were retained for data abstraction. Eligible studies used T1-weighted MRI techniques and reported direct or indirect T1 measures to characterize Mn accumulation in the brain. Findings demonstrate that, in subjects exposed to high levels of Mn, deposition in the brain is widespread, accumulating both within and outside the basal ganglia. Available evidence indicates that T1 MRI techniques can be used to distinguish Mn-exposed individuals from unexposed. Additionally, T1 MRI may be useful for semi-quantitative evaluation of inhaled Mn exposure, particularly when interpreted along with other exposure indices. T1 MRI measures appear to have a nonlinear relationship to Mn exposure duration, with R1 signal only increasing after critical thresholds. The strength of the association varied depending on the regions of interest imaged and the method of exposure measurement. Overall, available evidence suggests potential for future clinical and risk assessment applications of MRI as a diagnostic tool.
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Affiliation(s)
- N Jensen
- Risk Sciences International, Ottawa, Canada.,School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - R Terrell
- Risk Sciences International, Ottawa, Canada.,School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - S Ramoju
- Risk Sciences International, Ottawa, Canada
| | - N Shilnikova
- Risk Sciences International, Ottawa, Canada.,McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, Canada
| | - N Farhat
- Risk Sciences International, Ottawa, Canada.,School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada.,School of Mathematics and Statistics, Carleton University, Ottawa, Canada
| | - N Karyakina
- Risk Sciences International, Ottawa, Canada.,McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, Canada
| | - B H Cline
- International Manganese Institute, Paris, France
| | - F Momoli
- Risk Sciences International, Ottawa, Canada.,School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - D Mattison
- Risk Sciences International, Ottawa, Canada.,School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada.,Arnold School of Public Health, University of South Carolina, Columbia, SC, USA
| | - D Krewski
- Risk Sciences International, Ottawa, Canada.,School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada.,McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, Canada.,School of Mathematics and Statistics, Carleton University, Ottawa, Canada
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Borgert CJ, Fuentes C, Burgoon LD. Principles of dose-setting in toxicology studies: the importance of kinetics for ensuring human safety. Arch Toxicol 2021; 95:3651-3664. [PMID: 34623454 PMCID: PMC8536606 DOI: 10.1007/s00204-021-03155-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 09/02/2021] [Indexed: 01/11/2023]
Abstract
Regulatory toxicology seeks to ensure that exposures to chemicals encountered in the environment, in the workplace, or in products pose no significant hazards and produce no harm to humans or other organisms, i.e., that chemicals are used safely. The most practical and direct means of ensuring that hazards and harms are avoided is to identify the doses and conditions under which chemical toxicity does not occur so that chemical concentrations and exposures can be appropriately limited. Modern advancements in pharmacology and toxicology have revealed that the rates and mechanisms by which organisms absorb, distribute, metabolize and eliminate chemicals-i.e., the field of kinetics-often determine the doses and conditions under which hazard, and harm, are absent, i.e., the safe dose range. Since kinetics, like chemical hazard and toxicity, are extensive properties that depend on the amount of the chemical encountered, it is possible to identify the maximum dose under which organisms can efficiently metabolize and eliminate the chemicals to which they are exposed, a dose that has been referred to as the kinetic maximum dose, or KMD. This review explains the rationale that compels regulatory toxicology to embrace the advancements made possible by kinetics, why understanding the kinetic relationship between the blood level produced and the administered dose of a chemical is essential for identifying the safe dose range, and why dose-setting in regulatory toxicology studies should be informed by estimates of the KMD rather than rely on the flawed concept of maximum-tolerated toxic dose, or MTD.
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Affiliation(s)
- C J Borgert
- Applied Pharmacology and Toxicology, Inc., Gainesville, FL, USA.
- Center for Environmental and Human Toxicology (CEHT), Department of Physiological Sciences, University of Florida College of Veterinary Medicine, Gainesville, FL, USA.
| | - C Fuentes
- Department of Statistics, Oregon State University, Corvallis, OR, USA
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Edmondson DA, Ma RE, Yeh CL, Ward E, Snyder S, Azizi E, Zauber SE, Wells EM, Dydak U. Reversibility of neuroimaging markers influenced by lifetime occupational manganese exposure. Toxicol Sci 2019; 172:181-190. [PMID: 31388678 PMCID: PMC6813746 DOI: 10.1093/toxsci/kfz174] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 05/24/2019] [Accepted: 07/08/2019] [Indexed: 11/13/2022] Open
Abstract
Manganese (Mn) is a neurotoxicant that many workers are exposed to daily. There is limited knowledge about how changes in exposure levels impact measures in magnetic resonance imaging (MRI). We hypothesized that changes in Mn exposure would be reflected by changes in the MRI relaxation rate R1 and thalamic γ-aminobutyric acid (GABAThal). As part of a prospective cohort study, 17 welders were recruited and imaged on two separate occasions approximately two years apart. MRI relaxometry was used to assess changes of Mn accumulation in the brain. Additionally, GABA was measured using magnetic resonance spectroscopy (MRS) in the thalamic and striatal regions of the brain. Air Mn exposure ([Mn]Air) and cumulative exposure indexes of Mn (Mn-CEI) for the past three months (Mn-CEI3M), past year (Mn-CEI12M), and lifetime (Mn-CEILife) were calculated using personal air sampling and a comprehensive work history, while toenails were collected for analysis of internal Mn body burden. Finally, welders' motor function was examined using the Unified Parkinson's Disease Rating Scale (UPDRS). Median exposure decreased for all exposure measures between the first and second scan. ΔGABAThal was significantly correlated with ΔMn-CEI3M (ρ = 0.66, adjusted p = 0.02), ΔMn-CEI12M (ρ = 0.70, adjusted p = 0.006) , and Δ[Mn]Air (ρ = 0.77, adjusted p = 0.002). ΔGABAThal significantly decreased linearly with ΔMn-CEI3M (quantile regression, β = 15.22, p = 0.02) as well as Δ[Mn]Air (β = 1.27, p = 0.04). Finally, Mn-CEILife interacted with Δ[Mn]Air in the substantia nigra where higher Mn-CEILife lessened the ΔR1 per Δ[Mn]Air (F-test, p = 0.005). While R1 and GABA changed with Mn exposure, UPDRS was unaffected. In conclusion, our study shows that effects from changes in Mn exposure are reflected in thalamic GABA levels and brain Mn levels, as measured by R1, in most brain regions.
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Affiliation(s)
- David A Edmondson
- School of Health Sciences, Purdue University, West Lafayette, IN.,Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN
| | - Ruoyun E Ma
- School of Health Sciences, Purdue University, West Lafayette, IN.,Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN.,Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN
| | - Chien-Lin Yeh
- School of Health Sciences, Purdue University, West Lafayette, IN.,Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN
| | - Eric Ward
- School of Health Sciences, Purdue University, West Lafayette, IN
| | - Sandy Snyder
- School of Health Sciences, Purdue University, West Lafayette, IN
| | - Elham Azizi
- Department of Neurology, Ochsner Medical Center, Kenner, LA
| | - S Elizabeth Zauber
- Department of Neurology, Indiana University School of Medicine, Indianapolis, IN
| | - Ellen M Wells
- School of Health Sciences, Purdue University, West Lafayette, IN.,Public Health Graduate Program, Purdue University, West Lafayette, IN
| | - Ulrike Dydak
- School of Health Sciences, Purdue University, West Lafayette, IN.,Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN
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9
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Cortez-Lugo M, Riojas-Rodríguez H, Moreno-Macías H, Montes S, Rodríguez-Agudelo Y, Hernández-Bonilla D, Catalán-Vázquez M, Díaz-Godoy R, Rodríguez-Dozal S. Evaluation of the effect of an environmental management program on exposure to manganese in a mining zone in Mexico. Neurotoxicology 2018; 64:142-151. [DOI: 10.1016/j.neuro.2017.08.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 08/31/2017] [Accepted: 08/31/2017] [Indexed: 12/19/2022]
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10
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Bailey LA, Beck BD. Comment on "Environmental exposure to manganese in air: Associations with tremor and motor function" by Bowler et al. (2016). Sci Total Environ 2017; 595:839-841. [PMID: 28411567 DOI: 10.1016/j.scitotenv.2017.03.277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/29/2017] [Accepted: 03/30/2017] [Indexed: 06/07/2023]
Affiliation(s)
- Lisa A Bailey
- Gradient, 20 University Road, Cambridge, MA 02138, USA.
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11
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Gentry PR, Van Landingham C, Fuller WG, Sulsky SI, Greene TB, Clewell HJ, Andersen ME, Roels HA, Taylor MD, Keene AM. A tissue dose-based comparative exposure assessment of manganese using physiologically based pharmacokinetic modeling-The importance of homeostatic control for an essential metal. Toxicol Appl Pharmacol 2017; 322:27-40. [PMID: 28237878 DOI: 10.1016/j.taap.2017.02.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 02/17/2017] [Accepted: 02/20/2017] [Indexed: 01/27/2023]
Abstract
A physiologically-based pharmacokinetic (PBPK) model (Schroeter et al., 2011) was applied to simulate target tissue manganese (Mn) concentrations following occupational and environmental exposures. These estimates of target tissue Mn concentrations were compared to determine margins of safety (MOS) and to evaluate the biological relevance of applying safety factors to derive acceptable Mn air concentrations. Mn blood concentrations measured in occupational studies permitted verification of the human PBPK models, increasing confidence in the resulting estimates. Mn exposure was determined based on measured ambient air Mn concentrations and dietary data in Canada and the United States (US). Incorporating dietary and inhalation exposures into the models indicated that increases in target tissue concentrations above endogenous levels only begin to occur when humans are exposed to levels of Mn in ambient air (i.e. >10μg/m3) that are far higher than those currently measured in Canada or the US. A MOS greater than three orders of magnitude was observed, indicating that current Mn air concentrations are far below concentrations that would be required to produce the target tissue Mn concentrations associated with subclinical neurological effects. This application of PBPK modeling for an essential element clearly demonstrates that the conventional application of default factors to "convert" an occupational exposure to an equivalent continuous environmental exposure, followed by the application of safety factors, is not appropriate in the case of Mn. PBPK modeling demonstrates that the relationship between ambient Mn exposures and dose-to-target tissue is not linear due to normal tissue background levels and homeostatic controls.
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Affiliation(s)
- P Robinan Gentry
- Ramboll Environ US Corporation, 3701 Armand St., Monroe, LA 71201, United States.
| | | | - William G Fuller
- Ramboll Environ US Corporation, 3701 Armand St., Monroe, LA 71201, United States
| | | | - Tracy B Greene
- Ramboll Environ US Corporation, 3701 Armand St., Monroe, LA 71201, United States
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Ramoju SP, Mattison DR, Milton B, McGough D, Shilnikova N, Clewell HJ, Yoon M, Taylor MD, Krewski D, Andersen ME. The application of PBPK models in estimating human brain tissue manganese concentrations. Neurotoxicology 2017; 58:226-237. [PMID: 27989617 DOI: 10.1016/j.neuro.2016.12.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 12/01/2016] [Accepted: 12/01/2016] [Indexed: 01/16/2023]
Affiliation(s)
- Siva P Ramoju
- Risk Sciences International, 55 Metcalfe Street, Suite 700, K1P 6L5, Ottawa, Canada.
| | - Donald R Mattison
- Risk Sciences International, 55 Metcalfe Street, Suite 700, K1P 6L5, Ottawa, Canada; Samuel R. McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, 850 Peter Morand Crescent, Room 119, University of Ottawa, Ottawa, K1G 3Z7, Canada
| | - Brittany Milton
- Risk Sciences International, 55 Metcalfe Street, Suite 700, K1P 6L5, Ottawa, Canada
| | - Doreen McGough
- International Manganese Institute, 17 rue Duphot, 75001 Paris, France
| | - Natalia Shilnikova
- Risk Sciences International, 55 Metcalfe Street, Suite 700, K1P 6L5, Ottawa, Canada; Samuel R. McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, 850 Peter Morand Crescent, Room 119, University of Ottawa, Ottawa, K1G 3Z7, Canada
| | - Harvey J Clewell
- ScitoVation, 6 Davis Drive, PO Box 110566, Research Triangle Park, NC 27709,United States
| | - Miyoung Yoon
- ScitoVation, 6 Davis Drive, PO Box 110566, Research Triangle Park, NC 27709,United States
| | - Michael D Taylor
- Nickel Producers Environmental Research Association (NiPERA), 2525 Meridian Parkway, Suite 240, Durham, NC 27713, United States
| | - Daniel Krewski
- Risk Sciences International, 55 Metcalfe Street, Suite 700, K1P 6L5, Ottawa, Canada; Samuel R. McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, 850 Peter Morand Crescent, Room 119, University of Ottawa, Ottawa, K1G 3Z7, Canada
| | - Melvin E Andersen
- ScitoVation, 6 Davis Drive, PO Box 110566, Research Triangle Park, NC 27709,United States
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Hernández-Bonilla D, Escamilla-Núñez C, Mergler D, Rodríguez-Dozal S, Cortez-Lugo M, Montes S, Tristán-López LA, Catalán-Vázquez M, Schilmann A, Riojas-Rodriguez H. Effects of manganese exposure on visuoperception and visual memory in schoolchildren. Neurotoxicology 2016; 57:230-240. [PMID: 27737811 DOI: 10.1016/j.neuro.2016.10.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 10/08/2016] [Accepted: 10/08/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Manganese (Mn) is an essential metal involved in multiple physiological functions. Environmental exposure to airborne Mn is associated with neurocognitive deficits in humans. Children, whose nervous system is in development, are particularly susceptible to Mn neurotoxicity. OBJECTIVE The objective of this study was to assess the association between Mn environmental exposure, and effects on visuoperception and visual memory in schoolchildren. METHODS We assessed schoolchildren between 7 and 11 years old, with similar socioeconomic status, from the mining district of Molango (n=148) and Agua Blanca (n=119, non-mining area) in Hidalgo state, Mexico. The Rey-Osterrieth Complex Figure (ROCF) test was used to assess visuoperception and short-term visual memory. Hair manganese (MnH) concentrations were determined. Linear regression models were constructed to estimate the associations between MnH and ROCF scores, adjusted for potential confounders. RESULTS The geometric mean MnH was nine times higher in schoolchildren from the Mn mining area (5.25μg/g) than in schoolchildren from the non-mining area (0.55μg/g). For the ROCF Copy trial, MnH was significantly associated with an increase in distortion errors (tangency, closure), angle errors, overtracing (partial overtracing). In the Immediate Recall trial, MnH was significantly associated with increased overtracing (partial overtracing) and omissions, and negatively associated with the number of perceptual drawn units, total score and percentage immediate recall. CONCLUSIONS MnH is associated with alterations in visuoperception and short-term visual memory in schoolchildren exposed to airborne Mn.
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Affiliation(s)
- D Hernández-Bonilla
- National Institute of Public Health, Environmental Health Department, Cuernavaca, Morelos, CP 62100, Mexico.
| | - C Escamilla-Núñez
- National Institute of Public Health, Environmental Health Department, Cuernavaca, Morelos, CP 62100, Mexico.
| | - D Mergler
- Centre for Interdisciplinary Research on Health and Well-being, Society and Environment (CINBIOSE), Université du Québec à Montréal, Montreal, Canada.
| | - S Rodríguez-Dozal
- National Institute of Public Health, Environmental Health Department, Cuernavaca, Morelos, CP 62100, Mexico.
| | - M Cortez-Lugo
- National Institute of Public Health, Environmental Health Department, Cuernavaca, Morelos, CP 62100, Mexico.
| | - S Montes
- National Institute of Neurology and Neurosurgery, Neurochemistry Department, Manuel Velasco Suárez, Mexico City, CP 14269, Mexico.
| | - L A Tristán-López
- National Institute of Neurology and Neurosurgery, Neurochemistry Department, Manuel Velasco Suárez, Mexico City, CP 14269, Mexico.
| | - M Catalán-Vázquez
- National Institute of Respiratory Diseases, Clinical Epidemiology Department, Mexico City, CP 14080, Mexico.
| | - A Schilmann
- National Institute of Public Health, Environmental Health Department, Cuernavaca, Morelos, CP 62100, Mexico.
| | - Horacio Riojas-Rodriguez
- National Institute of Public Health, Environmental Health Department, Cuernavaca, Morelos, CP 62100, Mexico.
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Mattison DR, Milton B, Krewski D, Levy L, Dorman DC, Aggett PJ, Roels HA, Andersen ME, Karyakina NA, Shilnikova N, Ramoju S, McGough D. Severity scoring of manganese health effects for categorical regression. Neurotoxicology 2016; 58:203-216. [PMID: 27637608 DOI: 10.1016/j.neuro.2016.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 08/24/2016] [Accepted: 09/04/2016] [Indexed: 11/29/2022]
Abstract
Characterizing the U-shaped exposure response relationship for manganese (Mn) is necessary for estimating the risk of adverse health from Mn toxicity due to excess or deficiency. Categorical regression has emerged as a powerful tool for exposure-response analysis because of its ability to synthesize relevant information across multiple studies and species into a single integrated analysis of all relevant data. This paper documents the development of a database on Mn toxicity designed to support the application of categorical regression techniques. Specifically, we describe (i) the conduct of a systematic search of the literature on Mn toxicity to gather data appropriate for dose-response assessment; (ii) the establishment of inclusion/exclusion criteria for data to be included in the categorical regression modeling database; (iii) the development of a categorical severity scoring matrix for Mn health effects to permit the inclusion of diverse health outcomes in a single categorical regression analysis using the severity score as the outcome variable; and (iv) the convening of an international expert panel to both review the severity scoring matrix and assign severity scores to health outcomes observed in studies (including case reports, epidemiological investigations, and in vivo experimental studies) selected for inclusion in the categorical regression database. Exposure information including route, concentration, duration, health endpoint(s), and characteristics of the exposed population was abstracted from included studies and stored in a computerized manganese database (MnDB), providing a comprehensive repository of exposure-response information with the ability to support categorical regression modeling of oral exposure data.
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Affiliation(s)
- Donald R Mattison
- Risk Sciences International, 55 Metcalfe Street, Suite 700, K1P 6L5, Ottawa, Canada; R. Samuel McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, University of Ottawa, 118-850 Peter Morand Drive, Canada.
| | - Brittany Milton
- Risk Sciences International, 55 Metcalfe Street, Suite 700, K1P 6L5, Ottawa, Canada
| | - Daniel Krewski
- Risk Sciences International, 55 Metcalfe Street, Suite 700, K1P 6L5, Ottawa, Canada; R. Samuel McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, University of Ottawa, 118-850 Peter Morand Drive, Canada
| | - Len Levy
- Institute of Environment and Health, Cranfield University, College Road, Cranfield MK43 0AL, Bedfordshire, United Kingdom
| | - David C Dorman
- College of Veterinary Medicine, North Carolina State University, 1060 William Moore Drive, Raleigh, NC 27607, USA
| | - Peter J Aggett
- School of Medicine and Health, Lancaster University, Bailrigg, Lancaster, LA1 4YW, United Kingdom
| | - Harry A Roels
- Louvain Centre for Toxicology and Applied Pharmacology (LTAP), Université catholique de Louvain, Avenue Mounier 53.02, 1200 Brussels, Belgium
| | - Melvin E Andersen
- ScitoVation, 6 Davis Drive, PO Box 110566, Research Triangle Park, NC, 27709-2137, USA
| | - Nataliya A Karyakina
- Risk Sciences International, 55 Metcalfe Street, Suite 700, K1P 6L5, Ottawa, Canada; R. Samuel McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, University of Ottawa, 118-850 Peter Morand Drive, Canada
| | - Natalia Shilnikova
- Risk Sciences International, 55 Metcalfe Street, Suite 700, K1P 6L5, Ottawa, Canada; R. Samuel McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, University of Ottawa, 118-850 Peter Morand Drive, Canada
| | - Siva Ramoju
- Risk Sciences International, 55 Metcalfe Street, Suite 700, K1P 6L5, Ottawa, Canada
| | - Doreen McGough
- International Manganese Institute, 17 rue Duphot, 75001 Paris, France.
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Abstract
The central nervous system's extrapyramidal system provides involuntary motor control to the muscles of the head, neck, and limbs. Toxicants that affect the extrapyramidal system are generally clinically characterized by impaired motor control, which is usually the result of basal ganglionic dysfunction. A variety of extrapyramidal syndromes are recognized in humans and include Parkinson's disease, secondary parkinsonism, other degenerative diseases of the basal ganglia, and clinical syndromes that result in dystonia, dyskinesia, essential tremor, and other forms of tremor and chorea. This chapter briefly reviews the anatomy of the extrapyramidal system and discusses several naturally occurring and experimental models that target the mammalian (nonhuman) extrapyramidal system. Topics discussed include extrapyramidal syndromes associated with antipsychotic drugs, carbon monoxide, reserpine, cyanide, rotenone, paraquat, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and manganese. In most cases, animals are used as experimental models to improve our understanding of the toxicity and pathogenesis of these agents. Another agent discussed in this chapter, yellowstar thistle poisoning in horses, however, represents an important spontaneous cause of parkinsonism that naturally occurs in animals. The central focus of the chapter is on animal models, especially the concordance between clinical signs, neurochemical changes, and neuropathology between animals and people.
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Affiliation(s)
- David Dorman
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
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16
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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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17
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Singh SP, Kumari M, Kumari SI, Rahman MF, Kamal SK, Mahboob M, Grover P. Genotoxicity of nano- and micron-sized manganese oxide in rats after acute oral treatment. Mutation Research/Genetic Toxicology and Environmental Mutagenesis 2013; 754:39-50. [DOI: 10.1016/j.mrgentox.2013.04.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/10/2013] [Accepted: 04/15/2013] [Indexed: 01/08/2023]
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18
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Singh SP, Kumari M, Kumari SI, Rahman MF, Mahboob M, Grover P. Toxicity assessment of manganese oxide micro and nanoparticles in Wistar rats after 28 days of repeated oral exposure. J Appl Toxicol 2013; 33:1165-79. [DOI: 10.1002/jat.2887] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 03/22/2013] [Accepted: 03/23/2013] [Indexed: 12/18/2022]
Affiliation(s)
- Shailendra Pratap Singh
- Toxicology Unit, Biology Division; Indian Institute of Chemical Technology; Hyderabad; 500 007; Andhra Pradesh; India
| | - Monika Kumari
- Toxicology Unit, Biology Division; Indian Institute of Chemical Technology; Hyderabad; 500 007; Andhra Pradesh; India
| | - Srinivas I. Kumari
- Toxicology Unit, Biology Division; Indian Institute of Chemical Technology; Hyderabad; 500 007; Andhra Pradesh; India
| | - Mohammed F. Rahman
- Toxicology Unit, Biology Division; Indian Institute of Chemical Technology; Hyderabad; 500 007; Andhra Pradesh; India
| | - M. Mahboob
- Toxicology Unit, Biology Division; Indian Institute of Chemical Technology; Hyderabad; 500 007; Andhra Pradesh; India
| | - Paramjit Grover
- Toxicology Unit, Biology Division; Indian Institute of Chemical Technology; Hyderabad; 500 007; Andhra Pradesh; India
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19
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Deo AK, Theil FP, Nicolas JM. Confounding Parameters in Preclinical Assessment of Blood–Brain Barrier Permeation: An Overview With Emphasis on Species Differences and Effect of Disease States. Mol Pharm 2013; 10:1581-95. [DOI: 10.1021/mp300570z] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Anand K. Deo
- UCB Pharma S.A., Chemin du Foriest, B-1420 Braine-l’Alleud,
Belgium
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