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Ke T, Rajoo A, Tinkov AA, Skalny AV, Tizabi Y, Rocha JBT, Bowman AB, Aschner M. Intestinal microbiota protects against methylmercury-induced neurotoxicity. Biometals 2024; 37:561-576. [PMID: 37973679 DOI: 10.1007/s10534-023-00554-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 10/14/2023] [Indexed: 11/19/2023]
Abstract
Methylmercury (MeHg) remains a global public health issue because of its frequent presence in human food sources obtained from the water. The excretion of MeHg in humans occurs slowly with a biological half-time of 32-47 days. Short-term MeHg exposure may cause long-lasting neurotoxicity. The excretion through feces is a major route in the demethylation of MeHg. Accumulating evidence suggests that the intestinal microbiota plays an important role in the demethylation of MeHg, thereby protecting the host from neurotoxic effects. Here, we discuss recent developments on the role of intestinal microbiota in MeHg metabolism, based on in vitro cell culture experiments, experimental animal studies and human investigations. Demethylation by intestinal bacteria is the rate-limiting step in MeHg metabolism and elimination. The identity of bacteria strains responsible for this biotransformation is currently unknown; however, the non-homogenous distribution of intestinal microbiota may lead to different demethylation rates in the intestinal tract. The maintenance of intestinal barrier function by intestinal microbiota may afford protection against MeHg-induced neurotoxicity, which warrant future investigations. We also discuss studies investigating the effects of MeHg exposure on the population structural stability of intestinal microbiota in several host species. Although this is an emerging area in metal toxicity, current research suggests that a change in certain phyla in the intestinal microbiota may indicate MeHg overexposure.
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Affiliation(s)
- Tao Ke
- Department of Biological Sciences, University of Delaware, Newark, DE, 19716, USA
| | - André Rajoo
- Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, FL, 33458, USA
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Alexey A Tinkov
- IM Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia, 119991
- Yaroslavl State University, Yaroslavl, Russia, 150003
- Institute of Cellular and Intracellular Symbiosis, Russian Academy of Sciences, Orenburg, Russia, 460000
| | - Anatoly V Skalny
- IM Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia, 119991
- Department of Medical Elementology, Peoples' Friendship University of Russia (RUDN University), Moscow, Russia, 117198
| | - Yousef Tizabi
- Department of Pharmacology, Howard University College of Medicine, Washington, DC, 20059, USA
| | - Joao B T Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, 97105900, RS, Brazil
| | - Aaron B Bowman
- School of Health Sciences, Purdue University, West Lafayette, IN, 47907-2051, USA
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue Forchheimer Building, Room 209, Bronx, NY, 10461, USA.
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Rodríguez-Viso P, Domene A, Sánchez A, Vélez D, Monedero V, Devesa V, Zúñiga M. Challenges and strategies for preventing intestinal damage associated to mercury dietary exposure. Toxicology 2023; 494:153580. [PMID: 37328091 DOI: 10.1016/j.tox.2023.153580] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/02/2023] [Accepted: 06/12/2023] [Indexed: 06/18/2023]
Abstract
Food represents the major risk factor for exposure to mercury in most human populations. Therefore, passage through the gastrointestinal tract plays a fundamental role in its entry into the organism. Despite the intense research carried out on the toxicity of Hg, the effects at the intestinal level have received increased attention only recently. In this review we first provide a critical appraisal of the recent advances on the toxic effects of Hg at the intestinal epithelium. Next, dietary strategies aimed to diminish Hg bioavailability or modulate the epithelial and microbiota responses will be revised. Food components and additives, including probiotics, will be considered. Finally, limitations of current approaches to tackle this problem and future lines of research will be discussed.
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Affiliation(s)
| | - Adrián Domene
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Paterna, Spain
| | - Alicia Sánchez
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Paterna, Spain
| | - Dinoraz Vélez
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Paterna, Spain
| | - Vicente Monedero
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Paterna, Spain
| | - Vicenta Devesa
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Paterna, Spain
| | - Manuel Zúñiga
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Paterna, Spain.
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3
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Rodríguez-Viso P, Domene A, Vélez D, Devesa V, Monedero V, Zúñiga M. Oral exposure to inorganic mercury or methylmercury elicits distinct pro-inflammatory and pro-oxidant intestinal responses in a mouse model system. Food Chem Toxicol 2023; 177:113801. [PMID: 37137463 DOI: 10.1016/j.fct.2023.113801] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 04/14/2023] [Accepted: 04/23/2023] [Indexed: 05/05/2023]
Abstract
Humans are mainly exposed to mercury (Hg) through contaminated foodstuffs. However, the effects of Hg on the intestinal tract have received little attention. We performed a subchronic exposure to inorganic mercury or methylmercury in mice through drinking water (1, 5 or 10 mg/L for four months) to evaluate their intestinal impact. Histological, biochemical and gene expression analyses showed that both Hg species induced oxidative stress in small intestine and colon, while inflammation was mainly detected in the colon. Increased fecal albumin content indicated a compromised epithelial barrier. Mucus production was possibly also affected, as an increase in Muc2 expression was detected. However, differential effects were detected between both Hg species. Activation of p38 MAPK and increased crypt depth were detected in colon only with MeHg. Minor differences in microbiota composition were detected between unexposed and exposed mice. Although significant differences were detected between both Hg species at 10 mg/L, only the relative abundances of low abundance taxa were affected. Concentrations of microbial-derived short-chain fatty acids were decreased, suggesting an effect on microbial metabolism or increased demand by the intestinal epithelium. Results obtained confirm previous in vitro studies and highlights the intestinal mucosa as an initial target of Hg.
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Affiliation(s)
- Pilar Rodríguez-Viso
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain.
| | - Adrián Domene
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain.
| | - Dinoraz Vélez
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain.
| | - Vicenta Devesa
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain.
| | - Vicente Monedero
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain.
| | - Manuel Zúñiga
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain.
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4
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Gut as the target tissue of mercury and the extraintestinal effects. Toxicology 2023; 484:153396. [PMID: 36521575 DOI: 10.1016/j.tox.2022.153396] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 12/09/2022] [Accepted: 12/09/2022] [Indexed: 12/15/2022]
Abstract
Mercury (Hg) is harmful to the environment and human health. The gut plays important roles as the biological, chemical, mechanical, and immune barriers in animals and human beings. It has been known that Hg can be absorbed and methylated/demethylated in the gut, on the other hand, the impacts of Hg to the gut (especially the gut microbiota) is less studied. This review paper summarizes the impacts of inorganic Hg (IHg) and methyl Hg (MeHg) on gut barriers and the extraintestinal effects (damage to other organs such as the liver and brain). Both IHg and MeHg were found to cause intestinal microbial disorders, abnormal metabolites production, tight junction damage, and immune responses in the gut. The damage to the gut also contributed to the extraintestinal effects like the hepatotoxicity by IHg and the neurotoxicity by MeHg. In all, it is proposed that the gut should be considered as an important target tissue of Hg exposure, and the regulation of gut microbiota may have the potential for the prevention and control of the toxicity of Hg.
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Chanihoon GQ, Afridi HI, Unar A, Talpur FN, Kalochi HB, Nassani R, Laghari N, Uddin N, Ghulam A, Chandio AUR. Selenium and mercury concentrations in biological samples from patients with COVID-19. J Trace Elem Med Biol 2022; 73:127038. [PMID: 35863260 PMCID: PMC9288246 DOI: 10.1016/j.jtemb.2022.127038] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 06/26/2022] [Accepted: 07/13/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND Coronavirus disease 2019 (COVID-19) is a systemic disease affecting multiple organs. Furthermore, viral infection depletes several trace elements and promotes complex biochemical reactions in the body. Smoking has been linked to the incidence of COVID-19 and associated mortality, and it may impact clinical effects, viral and bacterial conversion, and treatment outcomes. OBJECTIVES To study the relationship between severe acute respiratory syndrome coronavirus type 2 and the elemental concentrations of selenium (Se) and mercury (Hg) in biological samples from smokers and nonsmokers infected with the virus and in healthy individuals. METHOD We evaluated changes in the concentrations of essential (Se) and toxic (Hg) elements in biological samples (blood, nasal fluid, saliva, sputum, serum, and scalp hair) collected from male smokers and nonsmokers (aged 29-59 years) infected with COVID-19 and from healthy men in the same age group. The patients lived in different cities in Sindh Province, Pakistan. The Se and Hg concentrations were determined using atomic absorption spectrophotometry. RESULTS Se concentrations in all types of biological samples from smokers and nonsmokers with COVID-19 were lower than those of healthy smokers and nonsmokers. Hg concentrations were elevated in both smokers and nonsmokers with COVID-19. CONCLUSIONS In the current study, persons infected with COVID-19 had higher concentrations of toxic Hg, which could cause physiological disorders, and low concentrations of essential Se, which can also cause weakness. COVID-19 infection showed positive correlations with levels of mercury and selenium. Thus, additional clinical and experimental investigations are essential.
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Affiliation(s)
- Ghulam Qadir Chanihoon
- National Centre of Excellence in Analytical Chemistry, University of Sindh Jamshoro, Sindh, 76080, Pakistan
| | - Hassan Imran Afridi
- National Centre of Excellence in Analytical Chemistry, University of Sindh Jamshoro, Sindh, 76080, Pakistan.
| | - Ahsanullah Unar
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China.
| | - Farah Naz Talpur
- National Centre of Excellence in Analytical Chemistry, University of Sindh Jamshoro, Sindh, 76080, Pakistan
| | - Hadi Bakhsh Kalochi
- National Centre of Excellence in Analytical Chemistry, University of Sindh Jamshoro, Sindh, 76080, Pakistan
| | - Rayan Nassani
- Center for Computational Biology, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Nazia Laghari
- National Centre of Excellence in Analytical Chemistry, University of Sindh Jamshoro, Sindh, 76080, Pakistan
| | - Najam Uddin
- National Centre of Excellence in Analytical Chemistry, University of Sindh Jamshoro, Sindh, 76080, Pakistan
| | - Ali Ghulam
- Computerization and Network Section, Sindh Agriculture University, Sindh, Pakistan
| | - Anees Ur Rahman Chandio
- National Centre of Excellence in Analytical Chemistry, University of Sindh Jamshoro, Sindh, 76080, Pakistan
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Aragão WAB, Bittencourt LO, Lima LADO, de Souza MPC, Nogueira LS, Dionizio A, Buzalaf MAR, de Oliveira EHC, Crespo-Lopez ME, Lima RR. DNA Damage and Proteomic Profile Changes in Rat Salivary Glands After Chronic Exposure to Inorganic Mercury. Biol Trace Elem Res 2022; 200:3983-3995. [PMID: 35013890 DOI: 10.1007/s12011-021-02986-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/20/2021] [Indexed: 11/02/2022]
Abstract
Mercury (Hg) is a toxic metal that became a public health problem due to environmental contamination caused by anthropogenic activity. In this sense, oral homeostasis can undergo changes due to the toxic effects of metal on the salivary glands. Therefore, our objective was to investigate the proteomic and genotoxic changes in salivary glands after exposure to inorganic mercury (IHg). Forty Wistar rats that were divided into a control group, which received distilled water, and an exposed group, which received 0.375 mg/kg of mercury chloride for 45 days via orogastric gavage. After that, the animals were euthanized, and the parotid and submandibular glands were collected for analysis of the genotoxic effects, using the comet assay and proteome global profile assessment. The results showed that IHg promoted damage to cellular DNA associated with proteomic changes that showed events such as oxidative stress, mitochondrial dysfunction, changes in the cytoskeleton, and apoptosis. Therefore, these findings show a profile of molecular changes due to the interactions of IHg with several proteins and mechanisms inherent to the cell, which consequently may result in dysfunction of the salivary glands and impaired homeostasis of the oral cavity.
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Affiliation(s)
- Walessa Alana Bragança Aragão
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Augusto Corrêa Street, n. 01, Guamá, Belém, 66075-110, Brazil
| | - Leonardo Oliveira Bittencourt
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Augusto Corrêa Street, n. 01, Guamá, Belém, 66075-110, Brazil
| | - Leidiane Alencar de Oliveira Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Augusto Corrêa Street, n. 01, Guamá, Belém, 66075-110, Brazil
| | | | - Lygia Sega Nogueira
- Laboratory of Cell Culture and Cytogenetics, Environment Section, Evandro Chagas Institute, Ananindeua, Brazil
| | - Aline Dionizio
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil
| | | | | | - Maria Elena Crespo-Lopez
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Pará, Belém, Brazil
| | - Rafael Rodrigues Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Augusto Corrêa Street, n. 01, Guamá, Belém, 66075-110, Brazil.
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7
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Rodríguez-Viso P, Domene A, Vélez D, Devesa V, Monedero V, Zúñiga M. Mercury toxic effects on the intestinal mucosa assayed on a bicameral in vitro model: Possible role of inflammatory response and oxidative stress. Food Chem Toxicol 2022; 166:113224. [PMID: 35700822 DOI: 10.1016/j.fct.2022.113224] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/18/2022] [Accepted: 06/06/2022] [Indexed: 11/18/2022]
Abstract
Exposure to mercury (Hg) mostly occurs through diet, where it is mainly found as inorganic Hg [Hg(II)] or methylmercury (MeHg). In vivo studies have linked its exposure with neurological and renal diseases, however, its toxic effects upon the gastrointestinal tract are largely unknown. In order to evaluate the effect of Hg on intestinal mucosa, a bicameral system was employed with co-cultures of Caco-2 and HT29-MTX intestinal epithelial cells and THP-1 macrophages. Cells were exposed to Hg(II) and MeHg (0.1, 0.5, 1 mg/L) during 11 days. The results evidenced a greater pro-inflammatory response in cells exposed to Hg with increments of IL-8 (15-126%) and IL-1β release (39-63%), mainly induced by macrophages which switched to a M1 phenotype. A pro-oxidant response was also observed in both cell types with an increase in ROS/RNS levels (44-140%) and stress proteins expression. Intestinal cells treated with Hg displayed structural abnormalities, hypersecretion of mucus and defective tight junctions. An increased paracellular permeability (123-170%) at the highest concentrations of Hg(II) and MeHg and decreased capacity to restore injuries in the cell monolayer were also observed. All these toxic effects were governed by various inflammatory signalling pathways (p38 MAPK, JNK and NF-κB).
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Affiliation(s)
- Pilar Rodríguez-Viso
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain.
| | - Adrián Domene
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain.
| | - Dinoraz Vélez
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain.
| | - Vicenta Devesa
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain.
| | - Vicente Monedero
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain.
| | - Manuel Zúñiga
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Agustín Escardino 7, 46980, Paterna, Valencia, Spain.
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8
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Zahouani T, Pultorak K, Pay F, Medina AE, El-Metwally DE. Heavy metals from donor blood and breast milk products in the NICU. Pediatr Res 2022; 91:474-476. [PMID: 33824456 DOI: 10.1038/s41390-021-01501-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 01/12/2021] [Accepted: 03/12/2021] [Indexed: 11/09/2022]
Affiliation(s)
- Tarik Zahouani
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Katherine Pultorak
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Fulden Pay
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Pediatrics, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Alexandre E Medina
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Dina E El-Metwally
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, USA.
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Bolan S, Seshadri B, Keely S, Kunhikrishnan A, Bruce J, Grainge I, Talley NJ, Naidu R. Bioavailability of arsenic, cadmium, lead and mercury as measured by intestinal permeability. Sci Rep 2021; 11:14675. [PMID: 34282255 PMCID: PMC8289861 DOI: 10.1038/s41598-021-94174-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 06/25/2021] [Indexed: 12/17/2022] Open
Abstract
In this study, the intestinal permeability of metal(loid)s (MLs) such as arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) was examined, as influenced by gut microbes and chelating agents using an in vitro gastrointestinal/Caco-2 cell intestinal epithelium model. The results showed that in the presence of gut microbes or chelating agents, there was a significant decrease in the permeability of MLs (As-7.5%, Cd-6.3%, Pb-7.9% and Hg-8.2%) as measured by apparent permeability coefficient value (Papp), with differences in ML retention and complexation amongst the chelants and the gut microbes. The decrease in ML permeability varied amongst the MLs. Chelating agents reduce intestinal absorption of MLs by forming complexes thereby making them less permeable. In the case of gut bacteria, the decrease in the intestinal permeability of MLs may be associated to a direct protection of the intestinal barrier against the MLs or indirect intestinal ML sequestration by the gut bacteria through adsorption on bacterial surface. Thus, both gut microbes and chelating agents can be used to decrease the intestinal permeability of MLs, thereby mitigating their toxicity.
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Affiliation(s)
- Shiv Bolan
- Global Centre for Environmental Remediation, University of Newcastle, Callaghan, NSW, Australia
- Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, University of Newcastle, Callaghan, NSW, Australia
| | - Balaji Seshadri
- Global Centre for Environmental Remediation, University of Newcastle, Callaghan, NSW, Australia
- Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, University of Newcastle, Callaghan, NSW, Australia
| | - Simon Keely
- Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - Anitha Kunhikrishnan
- Global Centre for Environmental Remediation, University of Newcastle, Callaghan, NSW, Australia
| | - Jessica Bruce
- Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - Ian Grainge
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia
| | - Nicholas J Talley
- Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - Ravi Naidu
- Global Centre for Environmental Remediation, University of Newcastle, Callaghan, NSW, Australia.
- Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, University of Newcastle, Callaghan, NSW, Australia.
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Novo JP, Martins B, Raposo RS, Pereira FC, Oriá RB, Malva JO, Fontes-Ribeiro C. Cellular and Molecular Mechanisms Mediating Methylmercury Neurotoxicity and Neuroinflammation. Int J Mol Sci 2021; 22:ijms22063101. [PMID: 33803585 PMCID: PMC8003103 DOI: 10.3390/ijms22063101] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 03/06/2021] [Accepted: 03/15/2021] [Indexed: 02/06/2023] Open
Abstract
Methylmercury (MeHg) toxicity is a major environmental concern. In the aquatic reservoir, MeHg bioaccumulates along the food chain until it is consumed by riverine populations. There has been much interest in the neurotoxicity of MeHg due to recent environmental disasters. Studies have also addressed the implications of long-term MeHg exposure for humans. The central nervous system is particularly susceptible to the deleterious effects of MeHg, as evidenced by clinical symptoms and histopathological changes in poisoned humans. In vitro and in vivo studies have been crucial in deciphering the molecular mechanisms underlying MeHg-induced neurotoxicity. A collection of cellular and molecular alterations including cytokine release, oxidative stress, mitochondrial dysfunction, Ca2+ and glutamate dyshomeostasis, and cell death mechanisms are important consequences of brain cells exposure to MeHg. The purpose of this review is to organize an overview of the mercury cycle and MeHg poisoning events and to summarize data from cellular, animal, and human studies focusing on MeHg effects in neurons and glial cells. This review proposes an up-to-date compendium that will serve as a starting point for further studies and a consultation reference of published studies.
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Affiliation(s)
- João P. Novo
- Institute for Clinical and Biomedical Research (iCBR), Center for Innovative Biomedicine and Biotechnology (CIBB), and Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.P.N.); (B.M.); (R.S.R.); (F.C.P.)
| | - Beatriz Martins
- Institute for Clinical and Biomedical Research (iCBR), Center for Innovative Biomedicine and Biotechnology (CIBB), and Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.P.N.); (B.M.); (R.S.R.); (F.C.P.)
| | - Ramon S. Raposo
- Institute for Clinical and Biomedical Research (iCBR), Center for Innovative Biomedicine and Biotechnology (CIBB), and Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.P.N.); (B.M.); (R.S.R.); (F.C.P.)
- Experimental Biology Core, University of Fortaleza, Health Sciences, Fortaleza 60110-001, Brazil
| | - Frederico C. Pereira
- Institute for Clinical and Biomedical Research (iCBR), Center for Innovative Biomedicine and Biotechnology (CIBB), and Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.P.N.); (B.M.); (R.S.R.); (F.C.P.)
| | - Reinaldo B. Oriá
- Laboratory of Tissue Healing, Ontogeny and Nutrition, Department of Morphology and Institute of Biomedicine, School of Medicine, Federal University of Ceará, Fortaleza 60430-270, Brazil;
| | - João O. Malva
- Institute for Clinical and Biomedical Research (iCBR), Center for Innovative Biomedicine and Biotechnology (CIBB), and Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.P.N.); (B.M.); (R.S.R.); (F.C.P.)
- Correspondence: (J.O.M.); (C.F.-R.)
| | - Carlos Fontes-Ribeiro
- Institute for Clinical and Biomedical Research (iCBR), Center for Innovative Biomedicine and Biotechnology (CIBB), and Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.P.N.); (B.M.); (R.S.R.); (F.C.P.)
- Correspondence: (J.O.M.); (C.F.-R.)
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11
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Raposo RDS, Pinto DV, Moreira R, Dias RP, Fontes Ribeiro CA, Oriá RB, Malva JO. Methylmercury Impact on Adult Neurogenesis: Is the Worst Yet to Come From Recent Brazilian Environmental Disasters? Front Aging Neurosci 2020; 12:591601. [PMID: 33328968 PMCID: PMC7719787 DOI: 10.3389/fnagi.2020.591601] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 10/15/2020] [Indexed: 12/11/2022] Open
Abstract
Worldwide environmental tragedies of anthropogenic origin causing massive release of metals and other pollutants have been increasing considerably. These pollution outbreaks affect the ecosystems and impact human health. Among those tragedies, recent large-scale environmental disasters in Brazil strongly affected riverside populations, leading to high-risk exposure to methylmercury (MeHg). MeHg is highly neurotoxic to the developing brain. This toxicant causes neural stem cell dysfunction and neurodevelopmental abnormalities. However, less is known about the effects of MeHg in the postnatal neurogenic niche, which harbors neural stem cells and their progeny, in the adult brain. Therefore, taking in consideration the impact of MeHg in human health it is urgent to clarify possible associations between exposure to mercury, accelerated cognitive decline, and neurodegenerative diseases. In this perspectives paper, we discuss the neurotoxic mechanisms of MeHg on postnatal neurogenesis and the putative implications associated with accelerated brain aging and early-onset cognitive decline in populations highly exposed to this environmental neurotoxicant.
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Affiliation(s)
- Ramon da Silva Raposo
- Faculty of Medicine, Center for Innovative Biomedicine and Biotechnology (CIBB) and Institute of Pharmacology and Experimental Therapeutics, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, Coimbra, Portugal
- Experimental Biology Core, Health Sciences Center, University of Fortaleza, Fortaleza, Brazil
| | - Daniel Vieira Pinto
- Laboratory of Tissue Healing, Ontogeny and Nutrition, Department of Morphology, School of Medicine, Institute of Biomedicine, Federal University of Ceara, Fortaleza, Brazil
| | - Ricardo Moreira
- Faculty of Medicine, Center for Innovative Biomedicine and Biotechnology (CIBB) and Institute of Pharmacology and Experimental Therapeutics, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, Coimbra, Portugal
| | - Ronaldo Pereira Dias
- Laboratory of Tissue Healing, Ontogeny and Nutrition, Department of Morphology, School of Medicine, Institute of Biomedicine, Federal University of Ceara, Fortaleza, Brazil
| | - Carlos Alberto Fontes Ribeiro
- Faculty of Medicine, Center for Innovative Biomedicine and Biotechnology (CIBB) and Institute of Pharmacology and Experimental Therapeutics, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, Coimbra, Portugal
| | - Reinaldo Barreto Oriá
- Laboratory of Tissue Healing, Ontogeny and Nutrition, Department of Morphology, School of Medicine, Institute of Biomedicine, Federal University of Ceara, Fortaleza, Brazil
| | - João Oliveira Malva
- Faculty of Medicine, Center for Innovative Biomedicine and Biotechnology (CIBB) and Institute of Pharmacology and Experimental Therapeutics, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, Coimbra, Portugal
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Skalny AV, Lima TRR, Ke T, Zhou JC, Bornhorst J, Alekseenko SI, Aaseth J, Anesti O, Sarigiannis DA, Tsatsakis A, Aschner M, Tinkov AA. Toxic metal exposure as a possible risk factor for COVID-19 and other respiratory infectious diseases. Food Chem Toxicol 2020; 146:111809. [PMID: 33069759 PMCID: PMC7563920 DOI: 10.1016/j.fct.2020.111809] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/25/2020] [Accepted: 10/01/2020] [Indexed: 01/08/2023]
Abstract
Multiple medical, lifestyle, and environmental conditions, including smoking and particulate pollution, have been considered as risk factors for COronaVIrus Disease 2019 (COVID-19) susceptibility and severity. Taking into account the high level of toxic metals in both particulate matter (PM2.5) and tobacco smoke, the objective of this review is to discuss recent data on the role of heavy metal exposure in development of respiratory dysfunction, immunotoxicity, and severity of viral diseases in epidemiological and experimental studies, as to demonstrate the potential crossroads between heavy metal exposure and COVID-19 severity risk. The existing data demonstrate that As, Cd, Hg, and Pb exposure is associated with respiratory dysfunction and respiratory diseases (COPD, bronchitis). These observations corroborate laboratory findings on the role of heavy metal exposure in impaired mucociliary clearance, reduced barrier function, airway inflammation, oxidative stress, and apoptosis. The association between heavy metal exposure and severity of viral diseases, including influenza and respiratory syncytial virus has been also demonstrated. The latter may be considered a consequence of adverse effects of metal exposure on adaptive immunity. Therefore, reduction of toxic metal exposure may be considered as a potential tool for reducing susceptibility and severity of viral diseases affecting the respiratory system, including COVID-19.
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Affiliation(s)
- Anatoly V Skalny
- IM Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia; Federal Research Centre of Biological Systems and Agro-technologies of the Russian Academy of Sciences, Orenburg, Russia.
| | - Thania Rios Rossi Lima
- São Paulo State University - UNESP, Center for Evaluation of Environmental Impact on Human Health (TOXICAM), Botucatu, SP, Brazil; Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Tao Ke
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Ji-Chang Zhou
- School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong Province, China
| | - Julia Bornhorst
- Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Wuppertal, Germany
| | - Svetlana I Alekseenko
- I.I. Mechnikov North-Western State Medical University, St. Petersburg, Russia; K.A. Rauhfus Children's City Multidisciplinary Clinical Center for High Medical Technologies, St. Petersburg, Russia
| | - Jan Aaseth
- IM Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia; Research Department, Innlandet Hospital Trust, Brumunddal, Norway
| | - Ourania Anesti
- Laboratory of Toxicology, Medical School, University of Crete, Voutes, Heraklion, Crete, Greece; HERACLES Research Center on the Exposome and Health, Center for Interdisciplinary Research and Innovation, Aristotle University of Thessaloniki, Thermi, Greece
| | - Dimosthenis A Sarigiannis
- HERACLES Research Center on the Exposome and Health, Center for Interdisciplinary Research and Innovation, Aristotle University of Thessaloniki, Thermi, Greece; University School of Advanced Studies IUSS, Pavia, Italy
| | - Aristides Tsatsakis
- IM Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia; Laboratory of Toxicology, Medical School, University of Crete, Voutes, Heraklion, Crete, Greece
| | - Michael Aschner
- IM Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia; Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
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13
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Cabezas-Sanchez P, Rainieri S, Conlledo N, Barranco A, Sanz-Landaluze J, Camara C, Luque-Garcia JL. Impact of selenium co-administration on methylmercury exposed eleutheroembryos and adult zebrafish (Danio rerio): Changes in bioaccumulation and gene expression. CHEMOSPHERE 2019; 236:124295. [PMID: 31319311 DOI: 10.1016/j.chemosphere.2019.07.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 06/10/2023]
Abstract
Mercury still represents one of the most hazardous threats for the aquatic ecosystem due to its high toxicity, and the fact that it can be easily incorporated into the food chain by accumulation in fish as MeHg. On the other hand, selenium is a micronutrient that is part of different antioxidant enzymes that regulate the cellular redox state, and whose complex interaction with Hg has been extensively studied from a toxicological point of view. In order to evaluate the protective effect of Se(IV) co-administration against MeHg accumulation and toxicity, we have selected an in-vivo model at two developmental stages: zebrafish eleutheroembryos and adult fish. Embryos were exposed during 48 h to MeHg (5 or 25 μg/l) and a concentration of Se (IV) representing a molar ratio close to one (2.5 or 12.5 μg/l), while adult zebrafish were exposed during 72 h to either 25 μg/l of MeHg alone or co-exposed with 12.5 μg/l of Se (IV). A significant decrease in MeHg bioaccumulation factor was observed in eleutheroembryos co-exposed to Se(IV). A time-dependent accumulation of MeHg was observed in all the analyzed organs and tissues of adult fish, which was significantly reduced in the muscular tissue and the intestine by Se(IV) co-administration. However, such protection against MeHg bioaccumulation was not maintained in the brain and liver. The data derived from the gene expression analysis also demonstrated the protective effect of Se(IV) against MeHg-induced oxidative stress and the activation of different defense mechanisms by Se(IV) co-administration.
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Affiliation(s)
- Pablo Cabezas-Sanchez
- Department of Analytical Chemistry, Faculty of Chemistry, Complutense University of Madrid, Ciudad Universitaria, 28040, Madrid, Spain
| | - Sandra Rainieri
- Food Research Division, AZTI, Parque Tecnológico de Bizkaia, Astondo Bidea 609, 48160, Derio, Spain
| | - Nadia Conlledo
- Food Research Division, AZTI, Parque Tecnológico de Bizkaia, Astondo Bidea 609, 48160, Derio, Spain
| | - Alejandro Barranco
- Food Research Division, AZTI, Parque Tecnológico de Bizkaia, Astondo Bidea 609, 48160, Derio, Spain
| | - Jon Sanz-Landaluze
- Department of Analytical Chemistry, Faculty of Chemistry, Complutense University of Madrid, Ciudad Universitaria, 28040, Madrid, Spain
| | - Carmen Camara
- Department of Analytical Chemistry, Faculty of Chemistry, Complutense University of Madrid, Ciudad Universitaria, 28040, Madrid, Spain
| | - Jose L Luque-Garcia
- Department of Analytical Chemistry, Faculty of Chemistry, Complutense University of Madrid, Ciudad Universitaria, 28040, Madrid, Spain.
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14
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Li W, Wang WX. Inter-species differences of total mercury and methylmercury in farmed fish in Southern China: Does feed matter? THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 651:1857-1866. [PMID: 30317173 DOI: 10.1016/j.scitotenv.2018.10.095] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 10/07/2018] [Accepted: 10/07/2018] [Indexed: 06/08/2023]
Abstract
China is now the largest producer of marine farmed fish and there is a considerable concern of seafood safety due to potential mercury contamination. We analyzed both the total mercury (THg) and methylmercury (MeHg) concentrations in nine species of commercial fish from two marine-cage farms in Southern China. 13C and 15N stable isotopes were concurrently analyzed to identify the artificial feed sources and the trophic levels of farmed fish. Mercury concentrations of all species were much lower than the human health screening values and safety limits established by different countries. Mercury levels in artificial pellets were the main determinants of Hg accumulation in fish between two sites, while somatic growth dilution and size also played an important role. Among the different fish tissues, muscle was a major reservoir for Hg and contained the highest ratio of MeHg/THg, and liver was the second important organ for Hg accumulation in most fish species. Intestine was a critical organ for Hg biotransformation with its %MeHg differing greatly among different fish species. δ15N analysis could not be used to determine the trophic levels in culturing systems where artificial practices were involved. Based on the δ13C signatures, five species of fish were identified to solely feed on the artificial pellets, yet the Hg bioaccumulation differed significantly among these species. We therefore concluded that Hg bioaccumulation in different fish species may be dependent on their internal Hg biotransformation as well as their biokinetics.
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Affiliation(s)
- Wanze Li
- Marine Environmental Laboratory, HKUST Shenzhen Research Institute, Shenzhen 518057, China; Department of Ocean Science, Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong
| | - Wen-Xiong Wang
- Marine Environmental Laboratory, HKUST Shenzhen Research Institute, Shenzhen 518057, China; Department of Ocean Science, Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong.
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Eaton AD, Zimmermann C, Delaney B, Hurley BP. Primary human polarized small intestinal epithelial barriers respond differently to a hazardous and an innocuous protein. Food Chem Toxicol 2017; 106:70-77. [PMID: 28533127 DOI: 10.1016/j.fct.2017.05.038] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 05/17/2017] [Accepted: 05/18/2017] [Indexed: 02/08/2023]
Abstract
An experimental platform employing human derived intestinal epithelial cell (IEC) line monolayers grown on permeable Transwell® filters was previously investigated to differentiate between hazardous and innocuous proteins. This approach was effective at distinguishing these types of proteins and perturbation of monolayer integrity, particularly transepithelial electrical resistance (TEER), was the most sensitive indicator. In the current report, in vitro indicators of monolayer integrity, cytotoxicity, and inflammation were evaluated using primary (non-transformed) human polarized small intestinal epithelial barriers cultured on Transwell® filters to compare effects of a hazardous protein (Clostridium difficile Toxin A [ToxA]) and an innocuous protein (bovine serum albumin [BSA]). ToxA exerted a reproducible decrease on barrier integrity at doses comparable to those producing effects observed from cell line-derived IEC monolayers, with TEER being the most sensitive indicator. In contrast, BSA, tested at concentrations substantially higher than ToxA, did not cause changes in any of the tested variables. These results demonstrate a similarity in response to certain proteins between cell line-derived polarized IEC models and a primary human polarized small intestinal epithelial barrier model, thereby reinforcing the potential usefulness of cell line-derived polarized IECs as a valid experimental platform to differentiate between hazardous and non-hazardous proteins.
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Affiliation(s)
- A D Eaton
- Department of Pediatrics, Mucosal Immunology & Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | | | - B P Hurley
- Department of Pediatrics, Mucosal Immunology & Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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Hurley BP, Eaton AD, Zimmermann C, Delaney B. Polarized monolayer cultures of human intestinal epithelial cell lines exposed to intractable proteins - In vitro hazard identification studies. Food Chem Toxicol 2016; 98:262-268. [DOI: 10.1016/j.fct.2016.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/04/2016] [Accepted: 11/05/2016] [Indexed: 12/01/2022]
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17
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Pierozan P, Biasibetti H, Schmitz F, Ávila H, Fernandes CG, Pessoa-Pureur R, Wyse ATS. Neurotoxicity of Methylmercury in Isolated Astrocytes and Neurons: the Cytoskeleton as a Main Target. Mol Neurobiol 2016; 54:5752-5767. [DOI: 10.1007/s12035-016-0101-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 09/05/2016] [Indexed: 01/16/2023]
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18
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Hurley BP, Pirzai W, Eaton AD, Harper M, Roper J, Zimmermann C, Ladics GS, Layton RJ, Delaney B. An experimental platform using human intestinal epithelial cell lines to differentiate between hazardous and non-hazardous proteins. Food Chem Toxicol 2016; 92:75-87. [DOI: 10.1016/j.fct.2016.04.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 04/01/2016] [Accepted: 04/04/2016] [Indexed: 10/22/2022]
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19
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Toxic trace elements at gastrointestinal level. Food Chem Toxicol 2015; 86:163-75. [PMID: 26482641 DOI: 10.1016/j.fct.2015.10.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 10/08/2015] [Accepted: 10/11/2015] [Indexed: 11/22/2022]
Abstract
Many trace elements are considered essential [iron (Fe), zinc (Zn), copper (Cu)], whereas others may be harmful [lead (Pb), cadmium (Cd), mercury (Hg), arsenic (As)], depending on their concentration and chemical form. In most cases, the diet is the main pathway by which they enter our organism. The presence of toxic trace elements in food has been known for a long time, and many of the food matrices that carry them have been identified. This has led to the appearance of legislation and recommendations concerning consumption. Given that the main route of exposure is oral, passage through the gastrointestinal tract plays a fundamental role in their entry into the organism, where they exert their toxic effect. Although the digestive system can be considered to be of crucial importance in their toxicity, in most cases we do not know the events that occur during the passage of these elements through the gastrointestinal tract and of ascertaining whether they may have some kind of toxic effect on it. The aim of this review is to summarize available information on this subject, concentrating on the toxic trace elements that are of greatest interest for organizations concerned with food safety and health: Pb, Cd, Hg and As.
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Frye RE, Rose S, Slattery J, MacFabe DF. Gastrointestinal dysfunction in autism spectrum disorder: the role of the mitochondria and the enteric microbiome. MICROBIAL ECOLOGY IN HEALTH AND DISEASE 2015; 26:27458. [PMID: 25956238 PMCID: PMC4425813 DOI: 10.3402/mehd.v26.27458] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Revised: 04/09/2015] [Accepted: 04/10/2015] [Indexed: 12/26/2022]
Abstract
Autism spectrum disorder (ASD) affects a significant number of individuals worldwide with the prevalence continuing to grow. It is becoming clear that a large subgroup of individuals with ASD demonstrate abnormalities in mitochondrial function as well as gastrointestinal (GI) symptoms. Interestingly, GI disturbances are common in individuals with mitochondrial disorders and have been reported to be highly prevalent in individuals with co-occurring ASD and mitochondrial disease. The majority of individuals with ASD and mitochondrial disorders do not manifest a primary genetic mutation, raising the possibility that their mitochondrial disorder is acquired or, at least, results from a combination of genetic susceptibility interacting with a wide range of environmental triggers. Mitochondria are very sensitive to both endogenous and exogenous environmental stressors such as toxicants, iatrogenic medications, immune activation, and metabolic disturbances. Many of these same environmental stressors have been associated with ASD, suggesting that the mitochondria could be the biological link between environmental stressors and neurometabolic abnormalities associated with ASD. This paper reviews the possible links between GI abnormalities, mitochondria, and ASD. First, we review the link between GI symptoms and abnormalities in mitochondrial function. Second, we review the evidence supporting the notion that environmental stressors linked to ASD can also adversely affect both mitochondria and GI function. Third, we review the evidence that enteric bacteria that are overrepresented in children with ASD, particularly Clostridia spp., produce short-chain fatty acid metabolites that are potentially toxic to the mitochondria. We provide an example of this gut–brain connection by highlighting the propionic acid rodent model of ASD and the clinical evidence that supports this animal model. Lastly, we discuss the potential therapeutic approaches that could be helpful for GI symptoms in ASD and mitochondrial disorders. To this end, this review aims to help better understand the underlying pathophysiology associated with ASD that may be related to concurrent mitochondrial and GI dysfunction.
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Affiliation(s)
- Richard E Frye
- Autism Research Program, Arkansas Children's Hospital Research Institute, Little Rock, AR, USA.,Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA;
| | - Shannon Rose
- Autism Research Program, Arkansas Children's Hospital Research Institute, Little Rock, AR, USA.,Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - John Slattery
- Autism Research Program, Arkansas Children's Hospital Research Institute, Little Rock, AR, USA.,Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Derrick F MacFabe
- Kilee Patchell-Evans Autism Research Group, Division of Developmental Disabilities, Departments of Psychology and Psychiatry, University of Western Ontario, London, ON, Canada
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