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Schrenk D, Bignami M, Bodin L, Chipman JK, del Mazo J, Grasl‐Kraupp B, Hogstrand C, Hoogenboom L(R, Leblanc J, Nebbia CS, Nielsen E, Ntzani E, Petersen A, Sand S, Schwerdtle T, Vleminckx C, Marko D, Oswald IP, Piersma A, Routledge M, Schlatter J, Baert K, Gergelova P, Wallace H. Risk assessment of aflatoxins in food. EFSA J 2020; 18:e06040. [PMID: 32874256 PMCID: PMC7447885 DOI: 10.2903/j.efsa.2020.6040] [Citation(s) in RCA: 115] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
EFSA was asked to deliver a scientific opinion on the risks to public health related to the presence of aflatoxins in food. The risk assessment was confined to aflatoxin B1 (AFB1), AFB2, AFG1, AFG2 and AFM1. More than 200,000 analytical results on the occurrence of aflatoxins were used in the evaluation. Grains and grain-based products made the largest contribution to the mean chronic dietary exposure to AFB1 in all age classes, while 'liquid milk' and 'fermented milk products' were the main contributors to the AFM1 mean exposure. Aflatoxins are genotoxic and AFB1 can cause hepatocellular carcinomas (HCCs) in humans. The CONTAM Panel selected a benchmark dose lower confidence limit (BMDL) for a benchmark response of 10% of 0.4 μg/kg body weight (bw) per day for the incidence of HCC in male rats following AFB1 exposure to be used in a margin of exposure (MOE) approach. The calculation of a BMDL from the human data was not appropriate; instead, the cancer potencies estimated by the Joint FAO/WHO Expert Committee on Food Additives in 2016 were used. For AFM1, a potency factor of 0.1 relative to AFB1 was used. For AFG1, AFB2 and AFG2, the in vivo data are not sufficient to derive potency factors and equal potency to AFB1 was assumed as in previous assessments. MOE values for AFB1 exposure ranged from 5,000 to 29 and for AFM1 from 100,000 to 508. The calculated MOEs are below 10,000 for AFB1 and also for AFM1 where some surveys, particularly for the younger age groups, have an MOE below 10,000. This raises a health concern. The estimated cancer risks in humans following exposure to AFB1 and AFM1 are in-line with the conclusion drawn from the MOEs. The conclusions also apply to the combined exposure to all five aflatoxins.
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Benkerroum N. Chronic and Acute Toxicities of Aflatoxins: Mechanisms of Action. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E423. [PMID: 31936320 PMCID: PMC7013914 DOI: 10.3390/ijerph17020423] [Citation(s) in RCA: 173] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/23/2019] [Accepted: 12/29/2019] [Indexed: 01/01/2023]
Abstract
There are presently more than 18 known aflatoxins most of which have been insufficiently studied for their incidence, health-risk, and mechanisms of toxicity to allow effective intervention and control means that would significantly and sustainably reduce their incidence and adverse effects on health and economy. Among these, aflatoxin B1 (AFB1) has been by far the most studied; yet, many aspects of the range and mechanisms of the diseases it causes remain to be elucidated. Its mutagenicity, tumorigenicity, and carcinogenicity-which are the best known-still suffer from limitations regarding the relative contribution of the oxidative stress and the reactive epoxide derivative (Aflatoxin-exo 8,9-epoxide) in the induction of the diseases, as well as its metabolic and synthesis pathways. Additionally, despite the well-established additive effects for carcinogenicity between AFB1 and other risk factors, e.g., hepatitis viruses B and C, and the hepatotoxic algal microcystins, the mechanisms of this synergy remain unclear. This study reviews the most recent advances in the field of the mechanisms of toxicity of aflatoxins and the adverse health effects that they cause in humans and animals.
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Affiliation(s)
- Noreddine Benkerroum
- Department of Food Science and Agricultural Chemistry MacDonald Campus, McGill University, 21111 Lakeshore, Ste Anne de Bellevue, QC H9X 3V9, Canada
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Wangia RN, Tang L, Wang JS. Occupational exposure to aflatoxins and health outcomes: a review. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2019; 37:215-234. [PMID: 31512547 DOI: 10.1080/10590501.2019.1664836] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Aflatoxins [AFs] are secondary metabolites of the fungus species Aspergillus spp. Both animal and epidemiological studies provided sufficient evidence on the carcinogenic, immunotoxic, mutagenic, and genotoxic potential of AFs. While ingestion is the main route of exposure for AFs through consumption of contaminated food products, agricultural workers and personnel who handle AF-contaminated grains are also at higher risk of exposure via inhalation. The main objective of the review is to provide a comprehensive overview of past scientific studies on occupational exposure to AFs, high-risk occupations, and disease outcomes. A search of peer-reviewed articles was done on PubMed and Web of Science Databases. A total of 164 papers was identified and 61 journal articles were selected for further review. High risk occupations include animal husbandry and processing of grain cereals and/or animal feed. Primary liver cancer and respiratory cancers were the most reported as a result of occupational exposure to AFs. For future studies, improved study designs, better characterization of AFs exposure in an occupational setting, and use of biomarkers are recommended in order to promote better understanding of occupational exposure to AFs and the resulting disease burden among workers.
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Affiliation(s)
- Ruth Nabwire Wangia
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, Georgia, USA
| | - Lili Tang
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, Georgia, USA
| | - Jia-Sheng Wang
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, Georgia, USA
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Jiang Y, Hansen PJ, Xiao Y, Amaral TF, Vyas D, Adesogan AT. Aflatoxin compromises development of the preimplantation bovine embryo through mechanisms independent of reactive oxygen production. J Dairy Sci 2019; 102:10506-10513. [PMID: 31521360 DOI: 10.3168/jds.2019-16839] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 07/11/2019] [Indexed: 01/12/2023]
Abstract
Aflatoxin is a potent carcinogen often found in animal feedstuffs. Although it reportedly impairs development of the preimplantation pig embryo, it is not known whether it adversely affects development of the preimplantation bovine embryo. We conducted 3 experiments to investigate this possibility and determine whether deleterious effects of aflatoxin were caused by increased production of reactive oxygen species (ROS). Experiments were conducted with embryos produced in vitro and cultured after fertilization with various concentrations of aflatoxin. For experiment 1, embryos were treated with 0 (control), 40, 400, or 4,000 µg/L of aflatoxin B1 (AFB1). Treatment at all concentrations of AFB1 tended to reduce cleavage rate, with the 2 highest concentrations having significant effects. As compared with the control, 40 µg/L AFB1 reduced the percentage of oocytes becoming blastocysts and the percentage of cleaved embryos becoming blastocysts (19.7 vs. 8.1% and 30.3 vs. 14.3%, respectively). Complete inhibition of blastocyst formation occurred at concentrations of 400 and 4,000 µg/L of AFB1. Experiments 2 and 3 involved a 2 × 2 factorial design with effects of AFB1 (0 and 40 µg/L), the antioxidant Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid, a water-soluble analog of vitamin E; 0 and 5 µM), and their interaction on production of ROS in putative zygotes (experiment 2) and development to the blastocyst stage (experiment 3). Production of ROS was increased by AFB1, and this effect was reversed by Trolox. However, Trolox did not prevent the reduction in development to the blastocyst stage caused by AFB1. Thus, the anti-developmental effects of AFB1 are not caused solely by increased ROS production. Rather, other underlying mechanisms exist for the adverse effects of aflatoxin on embryonic development. Overall, results indicate the potential for feeding aflatoxin-contaminated feed to cause embryonic loss in cattle.
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Affiliation(s)
- Y Jiang
- Department of Animal Sciences, University of Florida, Gainesville 32611
| | - P J Hansen
- Department of Animal Sciences, University of Florida, Gainesville 32611
| | - Y Xiao
- Department of Animal Sciences, University of Florida, Gainesville 32611
| | - T F Amaral
- Department of Animal Sciences, University of Florida, Gainesville 32611
| | - D Vyas
- Department of Animal Sciences, University of Florida, Gainesville 32611
| | - A T Adesogan
- Department of Animal Sciences, University of Florida, Gainesville 32611.
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Minko IG, Vartanian VL, Tozaki NN, Linde OK, Jaruga P, Coskun SH, Coskun E, Qu C, He H, Xu C, Chen T, Song Q, Jiao Y, Stone MP, Egli M, Dizdaroglu M, McCullough AK, Lloyd RS. Characterization of rare NEIL1 variants found in East Asian populations. DNA Repair (Amst) 2019; 79:32-39. [PMID: 31100703 DOI: 10.1016/j.dnarep.2019.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 04/30/2019] [Accepted: 05/01/2019] [Indexed: 10/26/2022]
Abstract
The combination of chronic dietary exposure to the fungal toxin, aflatoxin B1 (AFB1), and hepatitis B viral (HBV) infection is associated with an increased risk for early onset hepatocellular carcinomas (HCCs). An in-depth knowledge of the mechanisms driving carcinogenesis is critical for the identification of genetic risk factors affecting the susceptibility of individuals who are HBV infected and AFB1 exposed. AFB1-induced mutagenesis is characterized by G to T transversions. Hence, the DNA repair pathways that function on AFB1-induced DNA adducts or base damage from HBV-induced inflammation are anticipated to have a strong role in limiting carcinogenesis. These pathways define the mutagenic burden in the target tissues and ultimately limit cellular progression to cancer. Murine data have demonstrated that NEIL1 in the DNA base excision repair pathway was significantly more important than nucleotide excision repair relative to elevated risk for induction of HCCs. These data suggest that deficiencies in NEIL1 could contribute to the initiation of HCCs in humans. To investigate this hypothesis, publicly-available data on variant alleles of NEIL1 were analyzed and compared with genome sequencing data from HCC tissues derived from individuals residing in Qidong County (China). Three variant alleles were identified and the corresponding A51V, P68H, and G245R enzymes were characterized for glycosylase activity on genomic DNA containing a spectrum of oxidatively-induced base damage and an oligodeoxynucleotide containing a site-specific AFB1-formamidopyrimidine guanine adduct. Although the efficiency of the P68H variant was modestly decreased, the A51V and G245R variants showed nearly wild-type activities. Consistent with biochemical findings, molecular modeling of these variants demonstrated only slight local structural alterations. However, A51V was highly temperature sensitive suggesting that its biological activity would be greatly reduced. Overall, these studies have direct human health relevance pertaining to genetic risk factors and biochemical pathways previously not recognized as germane to induction of HCCs.
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Affiliation(s)
- Irina G Minko
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97239, United States
| | - Vladimir L Vartanian
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97239, United States
| | - Naoto N Tozaki
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97239, United States
| | - Oskar K Linde
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97239, United States
| | - Pawel Jaruga
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, United States
| | - Sanem Hosbas Coskun
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, United States
| | - Erdem Coskun
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, United States
| | - Chunfeng Qu
- State Key Lab of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 100021, Beijing, China
| | - Huan He
- State Key Lab of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 100021, Beijing, China
| | - Chungui Xu
- State Key Lab of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 100021, Beijing, China
| | - Taoyang Chen
- Qidong Liver Cancer Institute & Qidong People's Hospital, Qidong, 226200, Jiangsu Province, China
| | - Qianqian Song
- State Key Lab of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 100021, Beijing, China
| | - Yuchen Jiao
- State Key Lab of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 100021, Beijing, China
| | - Michael P Stone
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, United States
| | - Martin Egli
- Department of Biochemistry, Vanderbilt University, Nashville, TN, 37232, United States
| | - Miral Dizdaroglu
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, United States
| | - Amanda K McCullough
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97239, United States; Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, 97239, United States
| | - R Stephen Lloyd
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97239, United States; Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, 97239, United States; Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, 97239, United States.
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