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Schrenk D, Bignami M, Bodin L, Chipman JK, del Mazo J, Grasl‐Kraupp B, Hogstrand C, (Ron) Hoogenboom L, Leblanc J, Nebbia CS, Nielsen E, Ntzani E, Petersen A, Sand S, Schwerdtle T, Wallace H, Benford D, Fürst P, Hart A, Rose M, Schroeder H, Vrijheid M, Ioannidou S, Nikolič M, Bordajandi LR, Vleminckx C. Update of the risk assessment of polybrominated diphenyl ethers (PBDEs) in food. EFSA J 2024; 22:e8497. [PMID: 38269035 PMCID: PMC10807361 DOI: 10.2903/j.efsa.2024.8497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024] Open
Abstract
The European Commission asked EFSA to update its 2011 risk assessment on polybrominated diphenyl ethers (PBDEs) in food, focusing on 10 congeners: BDE-28, -47, -49, -99, -100, -138, -153, -154, -183 and ‑209. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour and reproductive/developmental effects are the critical effects in rodent studies. For four congeners (BDE-47, -99, -153, -209) the Panel derived Reference Points, i.e. benchmark doses and corresponding lower 95% confidence limits (BMDLs), for endpoint-specific benchmark responses. Since repeated exposure to PBDEs results in accumulation of these chemicals in the body, the Panel estimated the body burden at the BMDL in rodents, and the chronic intake that would lead to the same body burden in humans. For the remaining six congeners no studies were available to identify Reference Points. The Panel concluded that there is scientific basis for inclusion of all 10 congeners in a common assessment group and performed a combined risk assessment. The Panel concluded that the combined margin of exposure (MOET) approach was the most appropriate risk metric and applied a tiered approach to the risk characterisation. Over 84,000 analytical results for the 10 congeners in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary Lower Bound exposure to PBDEs were meat and meat products and fish and seafood. Taking into account the uncertainties affecting the assessment, the Panel concluded that it is likely that current dietary exposure to PBDEs in the European population raises a health concern.
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Sayed TS, Maayah ZH, Zeidan HA, Agouni A, Korashy HM. Insight into the physiological and pathological roles of the aryl hydrocarbon receptor pathway in glucose homeostasis, insulin resistance, and diabetes development. Cell Mol Biol Lett 2022; 27:103. [PMID: 36418969 PMCID: PMC9682773 DOI: 10.1186/s11658-022-00397-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 10/25/2022] [Indexed: 11/24/2022] Open
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcriptional factor that mediates the toxicities of several environmental pollutants. Decades of research have been carried out to understand the role of AhR as a novel mechanism for disease development. Its involvement in the pathogenesis of cancer, cardiovascular diseases, rheumatoid arthritis, and systemic lupus erythematosus have long been known. One of the current hot research topics is investigating the role of AhR activation by environmental pollutants on glucose homeostasis and insulin secretion, and hence the pathogenesis of diabetes mellitus. To date, epidemiological studies have suggested that persistent exposure to environmental contaminants such as dioxins, with subsequent AhR activation increases the risk of specific comorbidities such as obesity and diabetes. The importance of AhR signaling in various molecular pathways highlights that the role of this receptor is far beyond just xenobiotic metabolism. The present review aims at providing significant insight into the physiological and pathological role of AhR and its regulated enzymes, such as cytochrome P450 1A1 (CYP1A1) and CYP1B1 in both types of diabetes. It also provides a comprehensive summary of the current findings of recent research studies investigating the role of the AhR/CYP1A1 pathway in insulin secretion and glucose hemostasis in the pancreas, liver, and adipose tissues. This review further highlights the molecular mechanisms involved, such as gluconeogenesis, hypoxia-inducible factor (HIF), oxidative stress, and inflammation.
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Affiliation(s)
- Tahseen S. Sayed
- grid.412603.20000 0004 0634 1084Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, 2713, Doha, Qatar
| | - Zaid H. Maayah
- grid.412603.20000 0004 0634 1084Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, 2713, Doha, Qatar
| | - Heba A. Zeidan
- grid.498552.70000 0004 0409 8340American School of Doha, Doha, Qatar
| | - Abdelali Agouni
- grid.412603.20000 0004 0634 1084Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, 2713, Doha, Qatar
| | - Hesham M. Korashy
- grid.412603.20000 0004 0634 1084Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, 2713, Doha, Qatar
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Ou K, Song J, Zhang S, Fang L, Lin L, Lan M, Chen M, Wang C. Prenatal exposure to a mixture of PAHs causes the dysfunction of islet cells in adult male mice: Association with type 1 diabetes mellitus. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 239:113695. [PMID: 35623150 DOI: 10.1016/j.ecoenv.2022.113695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/20/2022] [Accepted: 05/22/2022] [Indexed: 06/15/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) have been detected throughout the human body. Whether exposure to PAHs is associated with the incidence of type 1 diabetes mellitus should be investigated. To this end, pregnant mice were exposed to mixed PAHs (5, 50, or 500 μg/kg) once every other day during gestation. The adult male offspring displayed impaired glucose tolerance and reduced serum levels of glucagon and insulin. Immunohistochemical staining revealed increased numbers of apoptotic β-cells and a reduced β-cell mass in these males. The downregulated expression of pancreatic estrogen receptor α, androgen receptor, and transcription factor PDX1 was responsible for impacting β-cell development. The relatively reduced α-cell area was associated with downregulated ARX expression. The transcription of Isn2 and Gcg in pancreatic tissue was downregulated, which indicated that the function of β-cells and α-cells was impaired. Methylation levels in the Isn2 promotor were significantly elevated in mice prenatally exposed to 500 µg/kg PAHs, which was consistent with the change in its mRNA levels. The number of macrophages infiltrating islets was significantly increased, indicating that prenatal PAH exposure might reduce islet cell numbers in an autoimmune manner. This study shows that prenatal exposure to PAHs may promote the pathogenesis of type 1 diabetes mellitus.
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Affiliation(s)
- Kunlin Ou
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361005, PR China
| | - Jialin Song
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361005, PR China
| | - Siqi Zhang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361005, PR China
| | - Lu Fang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361005, PR China
| | - Lesi Lin
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361005, PR China
| | - Miaolin Lan
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361005, PR China
| | - Meng Chen
- College of Environment & Ecology, Xiamen University, Xiamen, Fujian 361005, PR China.
| | - Chonggang Wang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361005, PR China.
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Florian M, Li B, Patry D, Truong J, Caldwell D, Coughlan MC, Woodworth R, Yan J, Chen Q, Petrov I, Mahemuti L, Lalande M, Li N, Chan LHM, Willmore WG, Jin X. Interplay of Obesity, Ethanol, and Contaminant Mixture on Clinical Profiles of Cardiovascular and Metabolic Diseases: Evidence from an Animal Study. Cardiovasc Toxicol 2022; 22:558-578. [PMID: 35429258 PMCID: PMC9107407 DOI: 10.1007/s12012-022-09738-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 03/28/2022] [Indexed: 11/05/2022]
Abstract
Obesity, ethanol, and contaminants are known risk factors of cardiovascular and metabolic diseases (CMD). However, their interplay on clinical profiles of these diseases remains unclear, and thus were investigated in this study. Male lean or obese JCR rats were given water or 10% ethanol and orally treated with or without a contaminant mixture (CM) dissolved in corn oil and loaded on two cookies at 0, 1.6, or 16 mg/kg BW/day dose levels for 4 weeks. The CM consisted 22 environmental contaminants found in human blood or serum of Northern populations. Over 60 parameters related to CMD were examined. The results revealed that obesity in JCR rats resembles the clinical profiles of non-alcoholic fatty liver disease in humans. Obesity was also associated with increased serum and organ retention of mercury, one of the chemical components of CM. Exposure to ethanol lightened hyperlipidemia, increased liver retention of mercury, and increased risk for hypertension in the obese rats. CM lessened hyperlipidemia and hyperenzymemia, worsened systemic inflammation and increased the risk for hypertension in the obese rats. CM markedly increased serum ethanol levels with or without ethanol exposure. Tissue total mercury contents significantly correlated with clinical parameters with altered profiles by both ethanol and obesity. These results suggest that obese individuals may be more prone to contaminant accumulation. Ethanol and CM exposure can alter clinical profiles associated with obesity, which may lead to misdiagnosis of CMD associated with obesity. CM can alter endogenous production and/or metabolism of ethanol, further complicating disease progression, diagnosis, and treatment.
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Guo J, Zhang Y, Li B, Wang C. In utero exposure to phenanthrene induced islet cell dysfunction in adult mice: Sex differences in the effects and potential causes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 770:145295. [PMID: 33513515 DOI: 10.1016/j.scitotenv.2021.145295] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/08/2021] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
Epidemiological studies show that the burden of polycyclic aromatic hydrocarbons in human body is associated with the occurrence of insulin resistance and diabetes. In the present study, pregnant mice were exposed to phenanthrene (Phe) at doses of 0, 60 and 600 μg/kg body weight of by gavage once every 3 days. The female F1 mice at 120 days of age showed no change in their fasting glucose levels (FGLs) but exhibited significantly decreased homeostasis model assessment (HOMA) β-cell (49% and 43%) and significantly downregulated pancreatic proinsulin gene (ins2) transcription. The downregulation of transcription factors, such as PDX1, PAX4 and FGF21, indicated impaired development and function of β-cells. The significantly reduced α-cell mass in 60 and 600 μg/kg groups, and the significantly downregulated expression of proglucagon gene gcg and ARX in the 600 μg/kg group suggested that the development and function of α-cells had been impacted. The males exhibited significantly increased FGLs (1.14- and 1.15-fold) in Phe exposed treatments and significantly elevated HOMA β-cell (3.15-fold) in the 600 μg/kg group. Upregulated ins2 transcription and FGF21 protein in male mice prenatally exposed to 600 μg/kg Phe suggested that these animals appeared compensatory enhancement in β-cell function. The reduced serum estradiol levels and downregulated pancreatic estrogen receptor α and β were responsible for the dysfunction of β-cells in the females. In the males, the significantly elevated androgen levels in the 600 μg/kg group might be related to the upregulated ins2 transcription, and the increased expression of pancreatic FGF21 further demonstrated the enhancement of β-cell potential. The results will be helpful for assessing the risk of developing diabetes in adulthood after prenatal exposure to phenanthrene.
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Affiliation(s)
- Jiaojiao Guo
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, PR China
| | - Ying Zhang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, PR China
| | - Bingshui Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, PR China
| | - Chonggang Wang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, PR China.
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Hoyeck MP, Blair H, Ibrahim M, Solanki S, Elsawy M, Prakash A, Rick KRC, Matteo G, O'Dwyer S, Bruin JE. Long-term metabolic consequences of acute dioxin exposure differ between male and female mice. Sci Rep 2020; 10:1448. [PMID: 31996693 PMCID: PMC6989671 DOI: 10.1038/s41598-020-57973-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 12/23/2019] [Indexed: 12/04/2022] Open
Abstract
Epidemiological studies have consistently shown an association between exposure to environmental pollutants and diabetes risk in humans. We have previously shown that direct exposure of mouse and human islets (endocrine pancreas) to the highly persistent pollutant TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) causes reduced insulin secretion ex vivo. Furthermore, a single high-dose of TCDD (200 µg/kg) suppressed both fasting and glucose-induced plasma insulin levels and promoted beta-cell apoptosis after 7 days in male mice. The current study investigated the longer-term effects of a single high-dose TCDD injection (20 µg/kg) on glucose metabolism and beta cell function in male and female C57Bl/6 mice. TCDD-exposed males displayed modest fasting hypoglycemia for ~4 weeks post-injection, reduced fasting insulin levels for up to 6 weeks, increased insulin sensitivity, decreased beta cell area, and increased delta cell area. TCDD-exposed females also had long-term suppressed basal plasma insulin levels, and abnormal insulin secretion for up to 6 weeks. Unlike males, TCDD did not impact insulin sensitivity or islet composition in females, but did cause transient glucose intolerance 4 weeks post-exposure. Our results show that a single exposure to dioxin can suppress basal insulin levels long-term in both sexes, but effects on glucose homeostasis are sex-dependent.
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Affiliation(s)
- Myriam P Hoyeck
- Department of Biology & Institute of Biochemistry, Carleton University, Ottawa, ON, Canada
| | - Hannah Blair
- Department of Biology & Institute of Biochemistry, Carleton University, Ottawa, ON, Canada
| | - Muna Ibrahim
- Laboratory of Molecular and Cellular Medicine, Department of Cellular & Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Shivani Solanki
- Department of Biology & Institute of Biochemistry, Carleton University, Ottawa, ON, Canada
| | - Mariam Elsawy
- Department of Biology & Institute of Biochemistry, Carleton University, Ottawa, ON, Canada
| | - Arina Prakash
- Department of Biology & Institute of Biochemistry, Carleton University, Ottawa, ON, Canada
| | - Kayleigh R C Rick
- Department of Biology & Institute of Biochemistry, Carleton University, Ottawa, ON, Canada
| | - Geronimo Matteo
- Department of Biology & Institute of Biochemistry, Carleton University, Ottawa, ON, Canada
| | - Shannon O'Dwyer
- Laboratory of Molecular and Cellular Medicine, Department of Cellular & Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Jennifer E Bruin
- Department of Biology & Institute of Biochemistry, Carleton University, Ottawa, ON, Canada.
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MacFarlane EM, Bruin JE. Human Pluripotent Stem Cells: A Unique Tool for Toxicity Testing in Pancreatic Progenitor and Endocrine Cells. Front Endocrinol (Lausanne) 2020; 11:604998. [PMID: 33542706 PMCID: PMC7851047 DOI: 10.3389/fendo.2020.604998] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/27/2020] [Indexed: 12/18/2022] Open
Abstract
Diabetes prevalence is increasing worldwide, and epidemiological studies report an association between diabetes incidence and environmental pollutant exposure. There are >84,000 chemicals in commerce, many of which are released into the environment without a clear understanding of potential adverse health consequences. While in vivo rodent studies remain an important tool for testing chemical toxicity systemically, we urgently need high-throughput screening platforms in biologically relevant models to efficiently prioritize chemicals for in depth toxicity analysis. Given the increasing global burden of obesity and diabetes, identifying chemicals that disrupt metabolism should be a high priority. Pancreatic endocrine cells are key regulators of systemic metabolism, yet often overlooked as a target tissue in toxicology studies. Immortalized β-cell lines and primary human, porcine, and rodent islets are widely used for studying the endocrine pancreas in vitro, but each have important limitations in terms of scalability, lifespan, and/or biological relevance. Human pluripotent stem cell (hPSC) culture is a powerful tool for in vitro toxicity testing that addresses many of the limitations with other β-cell models. Current in vitro differentiation protocols can efficiently generate glucose-responsive insulin-secreting β-like cells that are not fully mature, but still valuable for high-throughput toxicity screening in vitro. Furthermore, hPSCs can be applied as a model of developing pancreatic endocrine cells to screen for chemicals that influence endocrine cell formation during critical windows of differentiation. Given their versatility, we recommend using hPSCs to identify potential β-cell toxins, which can then be prioritized as chemicals of concern for metabolic disruption.
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Ibrahim M, MacFarlane EM, Matteo G, Hoyeck MP, Rick KRC, Farokhi S, Copley CM, O'Dwyer S, Bruin JE. Functional cytochrome P450 1A enzymes are induced in mouse and human islets following pollutant exposure. Diabetologia 2020; 63:162-178. [PMID: 31776611 PMCID: PMC6890627 DOI: 10.1007/s00125-019-05035-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 08/30/2019] [Indexed: 02/08/2023]
Abstract
AIMS/HYPOTHESIS Exposure to environmental pollution has been consistently linked to diabetes incidence in humans, but the potential causative mechanisms remain unclear. Given the critical role of regulated insulin secretion in maintaining glucose homeostasis, environmental chemicals that reach the endocrine pancreas and cause beta cell injury are of particular concern. We propose that cytochrome P450 (CYP) enzymes, which are involved in metabolising xenobiotics, could serve as a useful biomarker for direct exposure of islets to pollutants. Moreover, functional CYP enzymes in islets could also impact beta cell physiology. The aim of this study was to determine whether CYP1A enzymes are activated in islets following direct or systemic exposure to environmental pollutants. METHODS Immortalised liver (HepG2) and rodent pancreatic endocrine cell lines (MIN6, βTC-6, INS1, α-TC1, α-TC3), as well as human islets, were treated in vitro with known CYP1A inducers 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 3-methylcholanthrene (3-MC). In addition, mice were injected with either a single high dose of TCDD or multiple low doses of TCDD in vivo, and islets were isolated 1, 7 or 14 days later. RESULTS CYP1A enzymes were not activated in any of the immortalised beta or alpha cell lines tested. However, both 3-MC and TCDD potently induced CYP1A1 gene expression and modestly increased CYP1A1 enzyme activity in human islets after 48 h. The induction of CYP1A1 in human islets by TCDD was prevented by cotreatment with a cytokine mixture. After a systemic single high-dose TCDD injection, CYP1A1 enzyme activity was induced in mouse islets ~2-fold, ~40-fold and ~80-fold compared with controls after 1, 7 and 14 days, respectively, in vivo. Multiple low-dose TCDD exposure in vivo also caused significant upregulation of Cyp1a1 in mouse islets. Direct TCDD exposure to human and mouse islets in vitro resulted in suppressed glucose-induced insulin secretion. A single high-dose TCDD injection resulted in lower plasma insulin levels, as well as a pronounced increase in beta cell death. CONCLUSIONS/INTERPRETATION Transient exposure to TCDD results in long-term upregulation of CYP1A1 enzyme activity in islets. This provides evidence for direct exposure of islets to lipophilic pollutants in vivo and may have implications for islet physiology.
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Affiliation(s)
- Muna Ibrahim
- Laboratory of Molecular and Cellular Medicine, Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Erin M MacFarlane
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Geronimo Matteo
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Myriam P Hoyeck
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Kayleigh R C Rick
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Salar Farokhi
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Catherine M Copley
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Shannon O'Dwyer
- Laboratory of Molecular and Cellular Medicine, Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Jennifer E Bruin
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.
- Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.
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Prevalence of heart attack and stroke and associated risk factors among Inuit in Canada: A comparison with the general Canadian population. Int J Hyg Environ Health 2019; 222:319-326. [DOI: 10.1016/j.ijheh.2018.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 12/08/2018] [Accepted: 12/11/2018] [Indexed: 11/18/2022]
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Singh K, Chan HM. Persistent organic pollutants and diabetes among Inuit in the Canadian Arctic. ENVIRONMENT INTERNATIONAL 2017; 101:183-189. [PMID: 28202225 DOI: 10.1016/j.envint.2017.02.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/02/2017] [Accepted: 02/03/2017] [Indexed: 05/26/2023]
Abstract
Type 2 diabetes is a chronic metabolic disease that is of increasing concern in Inuit communities. Behavioural factors such as physical inactivity and poor diet are well-known risk factors. Exposure to persistent organic pollutants (POPs) has emerged as an additional factor in the pathogenesis of diabetes. In this study, association between polychlorinated biphenyls (PCBs) and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) with diabetes in Canadian Inuit was examined. Data from the Adult Inuit Health Survey (2007-2008) of Inuit participants from the Canadian Arctic were analyzed. Self-reported diabetes (excluding gestational diabetes) and clinical measurement of fasting glucose were examined as outcomes. Association with individual PCB congeners, sum of dioxin-like PCBs (∑DL-PCB), non-dioxin-like PCBs (∑NDL-PCB), total PCBs (∑PCB), and p,p'-DDE were investigated using multiple regression models adjusted for confounding factors. Using different methods to incorporate serum lipids, highest vs. lowest quartile exposures to PCB-105, PCB-118, PCB-153, PCB-156, PCB-170, PCB-180, PCB-183, ∑PCB, and p,p'-DDE were associated with increased risk of diabetes. For these PCBs, odds ratios (ORs) ranged from 1.9-3.5 (lower 95% CI: 0.8-1.4, upper 95% CI: 4.4-9.0) and for p,p'-DDE the OR was 2.5 (lower 95% CI: 1.1-1.2, upper 95% CI: 5.9-6.0). The highest vs. lowest quartile exposure to most PCBs and p,p'-DDE were associated with an increase of fasting glucose by 3-7%. PCBs and p,p'-DDE were associated with increased risk of diabetes and higher fasting glucose level in a cross-sectional survey of Canadian Inuit. Cause-effect relationships of PCBs and p,p'-DDE with diabetes and diabetes-related outcomes need to be further investigated in a cohort study.
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Affiliation(s)
- Kavita Singh
- Department of Biology, University of Ottawa, Ontario K1N 6N5, Canada.
| | - Hing Man Chan
- Department of Biology, University of Ottawa, Ontario K1N 6N5, Canada.
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Desaulniers D, Cummings-Lorbetskie C, Li N, Xiao GH, Marro L, Khan N, Leingartner K. Sodium bisulfite pyrosequencing revealed that developmental exposure to environmental contaminant mixtures does not affect DNA methylation of DNA repeats in Sprague-Dawley rats. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2016; 80:32-52. [PMID: 27905861 DOI: 10.1080/15287394.2016.1231644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 08/29/2016] [Indexed: 06/06/2023]
Abstract
Hypomethylation of DNA repeats has been linked to diseases and cancer predisposition. Human studies suggest that higher blood concentrations of environmental contaminants (EC) correlate with levels of hypomethylation of DNA repeats in blood. The objective of this study was to examine the effect of in utero and/or lactational exposure to EC on the methylation of DNA repeats (LINE-1 and identifier element) in Sprague-Dawley rat pups at birth, at postnatal day (PND) 21, and in adulthood (PND78-86). From gestation day 0 to PND20, dams were exposed to a mixture "M" of polychlorinated biphenyls (PCB), pesticides, and methylmercury (MeHg), at 0.5 or 1 mg/kg/d (0.5M and M). At birth, some control (C) and M litters were cross-fostered to create the following in utero/postnatal exposure groups: C/C, M/C, C/M, M/M. Additional dams received 1.8 ng/kg/d of a mixture of aryl-hydrocarbon receptor (AhR) agonists (non-ortho-PCB, PC-dibenzodioxins, and PC-dibenzofurans) without or with 0.5M (0.5MAhR). Measurements of EC residue levels confirmed differences in their accumulation across treatments, age, and tissues. Although induction of hepatic detoxification enzyme activities (cytochrome P-450) demonstrated biological effects of treatments, the assessment of methylation in DNA repeats by sodium bisulfite pyrosequencing of liver, spleen, and thymus samples revealed no marked treatment-related effects but significant tissue- and age-related methylation differences. Further studies are required to determine whether absence of significant observable treatment effects on methylation of DNA repeats in the rat relate to tissue, strain, or species differences.
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Affiliation(s)
- Daniel Desaulniers
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Cathy Cummings-Lorbetskie
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Nanqin Li
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Gong-Hua Xiao
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Leonora Marro
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Nasrin Khan
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Karen Leingartner
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
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12
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Food contaminants and programming of type 2 diabetes: recent findings from animal studies. J Dev Orig Health Dis 2016; 7:505-512. [PMID: 27292028 DOI: 10.1017/s2040174416000210] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
It is now accepted that the way our health evolves with aging is intimately linked to the quality of our early life. The present review highlights the emerging data of Developmental Origins of Health and Disease field on developmental disruption by toxicants and their subsequent effect on type 2 diabetes. We report adverse neonatal effects of several food contaminants during pregnancy and lactation, among them bisphenol A, chlorpyrifos, perfluorinated chemicals on pancreas integrity and functionality in later life. The described alterations, in conjunction with disruption of β cell mass in early life, can lead to dysregulation of glucose metabolism, insulin synthesis, which facilitates the development of insulin resistance and progression of diabetes in the adult. Despite limited and often inconclusive epidemiologic and experimental data, more recent data clearly show that infants appear to be at increased risk of type 2 diabetes in later life. This may be a result of continued exposure to chemical food contaminants during the critical window of pancreas development. In societies already burdened with increased incidence of non-communicable chronic diseases, there is a clear need for information regarding the potential harmful effects of chemical food contaminants on adult health diseases.
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Robledo CA, Romano ME, Alonso-Magdalena P. Review of Current Evidence on the Impact of Environmental Chemicals on Gestational Diabetes Mellitus. CURR EPIDEMIOL REP 2016. [DOI: 10.1007/s40471-016-0070-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Mailloux RJ, Yumvihoze E, Chan HM. Superoxide produced in the matrix of mitochondria enhances methylmercury toxicity in human neuroblastoma cells. Toxicol Appl Pharmacol 2015; 289:371-80. [DOI: 10.1016/j.taap.2015.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 10/28/2015] [Accepted: 11/02/2015] [Indexed: 01/08/2023]
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