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Hassan R, Gerdemann A, Cramer B, Hobloss Z, Myllys M, González D, Albrecht W, Veerkamp J, Friebel A, Hoehme S, Esselen M, Degen GH, Humpf HU, Hengstler JG, Ghallab A. Integrated data from intravital imaging and HPLC-MS/MS analysis reveal large interspecies differences in AFB 1 metabolism in mice and rats. Arch Toxicol 2024; 98:1081-1093. [PMID: 38436695 DOI: 10.1007/s00204-024-03688-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 01/23/2024] [Indexed: 03/05/2024]
Abstract
Large interspecies differences between rats and mice concerning the hepatotoxicity and carcinogenicity of aflatoxin B1 (AFB1) are known, with mice being more resistant. However, a comprehensive interspecies comparison including subcellular liver tissue compartments has not yet been performed. In this study, we performed spatio-temporal intravital analysis of AFB1 kinetics in the livers of anesthetized mice and rats. This was supported by time-dependent analysis of the parent compound as well as metabolites and adducts in blood, urine, and bile of both species by HPLC-MS/MS. The integrated data from intravital imaging and HPLC-MS/MS analysis revealed major interspecies differences between rats and mice: (1) AFB1-associated fluorescence persisted much longer in the nuclei of rat than mouse hepatocytes; (2) in the sinusoidal blood, AFB1-associated fluorescence was rapidly cleared in mice, while a time-dependent increase was observed in rats in the first three hours after injection followed by a plateau that lasted until the end of the observation period of six hours; (3) this coincided with a far stronger increase of AFB1-lysine adducts in the blood of rats compared to mice; (4) the AFB1-guanine adduct was detected at much higher concentrations in bile and urine of rats than mice. In both species, the AFB1-glutathione conjugate was efficiently excreted via bile, where it reached concentrations at least three orders of magnitude higher compared to blood. In conclusion, major differences between mice and rats were observed, concerning the nuclear persistence, formation of AFB1-lysine adducts, and the AFB1-guanine adducts.
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Affiliation(s)
- Reham Hassan
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystraße 67, 44139, Dortmund, Germany
- Department of Forensic Medicine and Toxicology, Faculty of Veterinary Medicine, South Valley University, Qena, 83523, Egypt
| | - Andrea Gerdemann
- Institute of Food Chemistry, University of Münster, Corrensstraße 45, 48149, Munster, Germany
| | - Benedikt Cramer
- Institute of Food Chemistry, University of Münster, Corrensstraße 45, 48149, Munster, Germany
| | - Zaynab Hobloss
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystraße 67, 44139, Dortmund, Germany
| | - Maiju Myllys
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystraße 67, 44139, Dortmund, Germany
| | - Daniela González
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystraße 67, 44139, Dortmund, Germany
| | - Wiebke Albrecht
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystraße 67, 44139, Dortmund, Germany
| | - Jannik Veerkamp
- Institute of Food Chemistry, University of Münster, Corrensstraße 45, 48149, Munster, Germany
| | - Adrian Friebel
- Institute of Computer Science and Saxonian Incubator for Clinical Research (SIKT), University of Leipzig, Haertelstraße 16-18, 04107, Leipzig, Germany
| | - Stefan Hoehme
- Institute of Computer Science and Saxonian Incubator for Clinical Research (SIKT), University of Leipzig, Haertelstraße 16-18, 04107, Leipzig, Germany
| | - Melanie Esselen
- Institute of Food Chemistry, University of Münster, Corrensstraße 45, 48149, Munster, Germany
| | - Gisela H Degen
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystraße 67, 44139, Dortmund, Germany
| | - Hans-Ulrich Humpf
- Institute of Food Chemistry, University of Münster, Corrensstraße 45, 48149, Munster, Germany.
| | - Jan G Hengstler
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystraße 67, 44139, Dortmund, Germany.
| | - Ahmed Ghallab
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystraße 67, 44139, Dortmund, Germany.
- Department of Forensic Medicine and Toxicology, Faculty of Veterinary Medicine, South Valley University, Qena, 83523, Egypt.
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Gerdemann A, Cramer B, Degen GH, Veerkamp J, Günther G, Albrecht W, Behrens M, Esselen M, Ghallab A, Hengstler JG, Humpf HU. Comparative metabolism of aflatoxin B 1 in mouse, rat and human primary hepatocytes using HPLC-MS/MS. Arch Toxicol 2023; 97:3179-3196. [PMID: 37794256 PMCID: PMC10567917 DOI: 10.1007/s00204-023-03607-z] [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: 07/03/2023] [Accepted: 09/14/2023] [Indexed: 10/06/2023]
Abstract
Aflatoxin B1 (AFB1) is a highly hepatotoxic and carcinogenic mycotoxin produced by Aspergillus species. The compound is mainly metabolized in the liver and its metabolism varies between species. The present study quantified relevant AFB1- metabolites formed by mouse, rat, and human primary hepatocytes after treatment with 1 µM and 10 µM AFB1. The use of liquid chromatographic separation coupled with tandem mass spectrometric detection enabled the selective and sensitive determination of phase I and phase II metabolites of AFB1 over incubation times of up to 24 h. The binding of AFB1 to macromolecules was also considered. The fastest metabolism of AFB1 was observed in mouse hepatocytes which formed aflatoxin P1 as a major metabolite and also its glucuronidated form, while AFP1 occurred only in traces in the other species. Aflatoxin M1 was formed in all species and was, together with aflatoxin Q1 and aflatoxicol, the main metabolite in human cells. Effective epoxidation led to high amounts of DNA adducts already 30 min post-treatment, especially in rat hepatocytes. Lower levels of DNA adducts and fast DNA repair were found in mouse hepatocytes. Also, protein adducts arising from reactive intermediates were formed rapidly in all three species. Detoxification via glutathione conjugation and subsequent formation of the N-acetylcysteine derivative appeared to be similar in mice and in rats and strongly differed from human hepatocytes which did not form these metabolites at all. The use of qualitative reference material of a multitude of metabolites and the comparison of hepatocyte metabolism in three species using advanced methods enabled considerations on toxification and detoxification mechanisms of AFB1. In addition to glutathione conjugation, phase I metabolism is strongly involved in the detoxification of AFB1.
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Affiliation(s)
- Andrea Gerdemann
- Institute of Food Chemistry, University of Münster, Corrensstraße 45, 48149 Münster, Germany
| | - Benedikt Cramer
- Institute of Food Chemistry, University of Münster, Corrensstraße 45, 48149 Münster, Germany
| | - Gisela H. Degen
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystraße 67, 44139 Dortmund, Germany
| | - Jannik Veerkamp
- Institute of Food Chemistry, University of Münster, Corrensstraße 45, 48149 Münster, Germany
| | - Georgia Günther
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystraße 67, 44139 Dortmund, Germany
| | - Wiebke Albrecht
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystraße 67, 44139 Dortmund, Germany
| | - Matthias Behrens
- Institute of Food Chemistry, University of Münster, Corrensstraße 45, 48149 Münster, Germany
| | - Melanie Esselen
- Institute of Food Chemistry, University of Münster, Corrensstraße 45, 48149 Münster, Germany
| | - Ahmed Ghallab
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystraße 67, 44139 Dortmund, Germany
- Department of Forensic Medicine and Toxicology, Faculty of Veterinary Medicine, South Valley University, Qena, 83523 Egypt
| | - Jan G. Hengstler
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystraße 67, 44139 Dortmund, Germany
| | - Hans-Ulrich Humpf
- Institute of Food Chemistry, University of Münster, Corrensstraße 45, 48149 Münster, Germany
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3
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Owumi SE, Ajakaiye B, Akinwunmi AO, Nwozo SO, Oyelere AK. The Hydrophobic Extract of Sorghum bicolor (L. Moench) Enriched in Apigenin-Protected Rats against Aflatoxin B1-Associated Hepatorenal Derangement. Molecules 2023; 28:molecules28073013. [PMID: 37049776 PMCID: PMC10095839 DOI: 10.3390/molecules28073013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 03/30/2023] Open
Abstract
Aflatoxin B1 (AFB1) is a recalcitrant metabolite produced by fungi species, and due to its intoxications in animals and humans, it has been classified as a Group 1 carcinogen in humans. Preserving food products with Sorghum bicolor sheath can minimise the contamination of agricultural products and avert ill health occasioned by exposure to AFB1. The current study investigated the ameliorating effect of Sorghum bicolor sheath hydrophobic extract (SBE-HP) enriched in Apigenin (API) on the hepatorenal tissues of rats exposed to AFB1. The SBE-HP was characterised using TLC and LC-MS and was found to be enriched in Apigenin and its methylated analogues. The study used adult male rats divided into four experimental cohorts co-treated with AFB1 (50 µg/kg) and SBE-HP (5 and 10 mg/kg) for 28 days. Biochemical, enzyme-linked immunosorbent assays (ELISA) and histological staining were used to examine biomarkers of hepatorenal function, oxidative status, inflammation and apoptosis, and hepatorenal tissue histo-architectural alterations. Data were analysed using GraphPad Prism 8.3.0, an independent t-test, and a one-way analysis of variance. Co-treatment with SBE-HP ameliorated an upsurge in the biomarkers of hepatorenal functionality in the sera of rats, reduced the alterations in redox balance, resolved inflammation, inhibited apoptosis, and preserved the histological features of the liver and kidney of rats exposed to AFB1. SBE-HP-containing API is an excellent antioxidant regiment. It can amply prevent the induction of oxidative stress, inflammation, and apoptosis in the hepatorenal system of rats. Therefore, supplementing animal feeds and human foods with SBE-HP enriched in Apigenin may reduce the burden of AFB1 intoxication in developing countries with a shortage of effective antifungal agents.
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Affiliation(s)
- Solomon E. Owumi
- Cancer Research and Molecular Biology Laboratories, Department of Biochemistry, Faculty of Basic Medical Sciences, University of Ibadan, Ibadan 200005, Nigeria
- Correspondence: (S.E.O.); (A.K.O.)
| | - Blessing Ajakaiye
- Nutrition and Industrial Biochemistry Laboratories, Department of Biochemistry, Faculty of Basic Medical Sciences, University of Ibadan, Ibadan 200005, Nigeria
| | - Adenike O. Akinwunmi
- Department of Chemistry, Ekiti State University, Ado-Ekiti, Ekiti 360001, Nigeria
| | - Sarah O. Nwozo
- Nutrition and Industrial Biochemistry Laboratories, Department of Biochemistry, Faculty of Basic Medical Sciences, University of Ibadan, Ibadan 200005, Nigeria
| | - Adegboyega K. Oyelere
- School of Chemistry & Biochemistry, Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Correspondence: (S.E.O.); (A.K.O.)
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4
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Purar B, Djalovic I, Bekavac G, Grahovac N, Krstović S, Latković D, Janić Hajnal E, Živančev D. Changes in Fusarium and Aspergillus Mycotoxin Content and Fatty Acid Composition after the Application of Ozone in Different Maize Hybrids. Foods 2022; 11:2877. [PMID: 36141007 PMCID: PMC9498628 DOI: 10.3390/foods11182877] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 11/24/2022] Open
Abstract
Mycotoxins in maize represent a great threat to human health. For this reason, novel technics such as ozone treatment are used to reduce the content of maize mycotoxins. However, there is little knowledge about the effect of ozone treatment on maize quality parameters. This study investigated the changes in Fusarium and Aspergillus mycotoxins and the changes in fatty acids during the ozone treatment of maize samples. Sixteen maize hybrids were visually tested for the naturally occurring ear rot severity and treated with three different concentrations of ozone (40, 70, and 85 mg/L). Mycotoxin content in maize samples was determined using a high-performance liquid chromatography (HPLC) system, whereas dominant fatty acids were determined using gas chromatography coupled with a flame ionization detector (GC-FID). Ozone treatments could be successfully applied to reduce the content of mycotoxins in maize below the detection limit. Ozone treatments increased the content of monounsaturated fatty acids (MUFAs) and decreased the content of polyunsaturated fatty acids (PUFAs), i.e., linoleic acid (36.7% in relation to the lowest applied ozone concentration), which negatively affected the nutritional value of maize.
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Affiliation(s)
- Božana Purar
- Institute of Field and Vegetable Crops, National Institute of the Republic of Serbia, Maxim Gorki 30, 21000 Novi Sad, Serbia
| | - Ivica Djalovic
- Institute of Field and Vegetable Crops, National Institute of the Republic of Serbia, Maxim Gorki 30, 21000 Novi Sad, Serbia
| | - Goran Bekavac
- Institute of Field and Vegetable Crops, National Institute of the Republic of Serbia, Maxim Gorki 30, 21000 Novi Sad, Serbia
| | - Nada Grahovac
- Institute of Field and Vegetable Crops, National Institute of the Republic of Serbia, Maxim Gorki 30, 21000 Novi Sad, Serbia
| | - Saša Krstović
- Faculty of Agriculture, University of Novi Sad, Sq. D. Obradovic 8, 21000 Novi Sad, Serbia
| | - Dragana Latković
- Faculty of Agriculture, University of Novi Sad, Sq. D. Obradovic 8, 21000 Novi Sad, Serbia
| | - Elizabet Janić Hajnal
- Institute of Food Technology, University of Novi Sad, Bul. Cara Lazara 1, 21000 Novi Sad, Serbia
| | - Dragan Živančev
- Institute of Field and Vegetable Crops, National Institute of the Republic of Serbia, Maxim Gorki 30, 21000 Novi Sad, Serbia
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5
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Gilbert‐Sandoval I, Wesseling S, Rietjens IMCM. Predicting the Acute Liver Toxicity of Aflatoxin B1 in Rats and Humans by an In Vitro-In Silico Testing Strategy. Mol Nutr Food Res 2020; 64:e2000063. [PMID: 32421213 PMCID: PMC7379280 DOI: 10.1002/mnfr.202000063] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 05/01/2020] [Indexed: 11/14/2022]
Abstract
SCOPE High-level exposure to aflatoxin B1 (AFB1) is known to cause acute liver damage and fatality in animals and humans. The intakes actually causing this acute toxicity have so far been estimated based on AFB1 levels in contaminated foods or biomarkers in serum. The aim of the present study is to predict the doses causing acute liver toxicity of AFB1 in rats and humans by an in vitro-in silico testing strategy. METHODS AND RESULTS Physiologically based kinetic (PBK) models for AFB1 in rats and humans are developed. The models are used to translate in vitro concentration-response curves for cytotoxicity in primary rat and human hepatocytes to in vivo dose-response curves using reverse dosimetry. From these data, the dose levels at which toxicity would be expected are obtained and compared to toxic dose levels from available rat and human case studies on AFB1 toxicity. The results show that the in vitro-in silico testing strategy can predict dose levels causing acute toxicity of AFB1 in rats and human. CONCLUSIONS Quantitative in vitro in vivo extrapolation (QIVIVE) using PBK modeling-based reverse dosimetry can predict AFB1 doses that cause acute liver toxicity in rats and human.
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Affiliation(s)
- Ixchel Gilbert‐Sandoval
- Division of ToxicologyWageningen University and ResearchStippeneng 4Wageningen6708 WEThe Netherlands
| | - Sebastiaan Wesseling
- Division of ToxicologyWageningen University and ResearchStippeneng 4Wageningen6708 WEThe Netherlands
| | - Ivonne M. C. M. Rietjens
- Division of ToxicologyWageningen University and ResearchStippeneng 4Wageningen6708 WEThe Netherlands
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6
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Gupta P, Gramatke A, Einspanier R, Schütte C, von Kleist M, Sharbati J. In silico cytotoxicity assessment on cultured rat intestinal cells deduced from cellular impedance measurements. Toxicol In Vitro 2017; 41:179-188. [PMID: 28263893 DOI: 10.1016/j.tiv.2017.02.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 02/16/2017] [Accepted: 02/27/2017] [Indexed: 11/16/2022]
Abstract
Early and reliable identification of chemical toxicity is of utmost importance. At the same time, reduction of animal testing is paramount. Therefore, methods that improve the interpretability and usability of in vitro assays are essential. xCELLigence's real-time cell analyzer (RTCA) provides a novel, fast and cost effective in vitro method to probe compound toxicity. We developed a simple mathematical framework for the qualitative and quantitative assessment of toxicity for RTCA measurements. Compound toxicity, in terms of its 50% inhibitory concentration IC50 on cell growth, and parameters related to cell turnover were estimated on cultured IEC-6 cells exposed to 10 chemicals at varying concentrations. Our method estimated IC50 values of 113.05, 7.16, 28.69 and 725.15 μM for the apparently toxic compounds 2-acetylamino-fluorene, aflatoxin B1, benzo-[a]-pyrene and chloramphenicol in the tested cell line, in agreement with literature knowledge. IC50 values of all apparent in vivo non-toxic compounds were estimated to be non-toxic by our method. Corresponding estimates from RTCA's in-built model gave false positive (toxicity) predictions in 5/10 cases. Taken together, our proposed method reduces false positive predictions and reliably identifies chemical toxicity based on impedance measurements. The source code for the developed method including instructions is available at https://git.zib.de/bzfgupta/toxfit/tree/master.
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Affiliation(s)
- P Gupta
- Department of Mathematics and Informatics, Freie Universität Berlin, Arnimallee 6, Berlin 14195, Germany; Department of Mathematics for Life and Materials Sciences, Zuse Institute Berlin, Takustrasse 7, Berlin 14195, Germany.
| | - A Gramatke
- Department of Veterinary Biochemistry, Freie Universität Berlin, Oertzenweg 19b, Building 12, Berlin 14163, Germany.
| | - R Einspanier
- Department of Veterinary Biochemistry, Freie Universität Berlin, Oertzenweg 19b, Building 12, Berlin 14163, Germany.
| | - C Schütte
- Department of Mathematics and Informatics, Freie Universität Berlin, Arnimallee 6, Berlin 14195, Germany; Department of Mathematics for Life and Materials Sciences, Zuse Institute Berlin, Takustrasse 7, Berlin 14195, Germany.
| | - M von Kleist
- Department of Mathematics and Informatics, Freie Universität Berlin, Arnimallee 6, Berlin 14195, Germany.
| | - J Sharbati
- Department of Veterinary Biochemistry, Freie Universität Berlin, Oertzenweg 19b, Building 12, Berlin 14163, Germany.
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7
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Abstract
The expression of gamma-glutamyl transpeptidase (GGT) is essential to maintaining cysteine levels in the body. GGT is a cell surface enzyme that hydrolyzes the gamma-glutamyl bond of extracellular reduced and oxidized glutathione, initiating their cleavage into glutamate, cysteine (cystine), and glycine. GGT is normally expressed on the apical surface of ducts and glands, salvaging the amino acids from glutathione in the ductal fluids. GGT in tumors is expressed over the entire cell membrane and provides tumors with access to additional cysteine and cystine from reduced and oxidized glutathione in the blood and interstitial fluid. Cysteine is rate-limiting for glutathione synthesis in cells under oxidative stress. The induction of GGT is observed in tumors with elevated levels of intracellular glutathione. Studies in models of hepatocarcinogenesis show that GGT expression in foci of preneoplastic hepatocytes provides a selective advantage to the cells during tumor promotion with agents that deplete intracellular glutathione. Similarly, expression of GGT in tumors enables cells to maintain elevated levels of intracellular glutathione and to rapidly replenish glutathione during treatment with prooxidant anticancer therapy. In the clinic, the expression of GGT in tumors is correlated with drug resistance. The inhibitors of GGT block GGT-positive tumors from accessing the cysteine in extracellular glutathione. They also inhibit GGT activity in the kidney, which results in the excretion of GSH in the urine and a rapid decrease in blood cysteine levels, leading to depletion of intracellular GSH in both GGT-positive and GGT-negative tumors. GGT inhibitors are being developed for clinical use to sensitize tumors to chemotherapy.
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Affiliation(s)
- Marie H Hanigan
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
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8
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LIU RENRONG, XU LING, QIU XUEMEI, CHEN XINGLONG, DENG SHENGLIANG, LAI WEIHUA, XU YANG. AN IMMUNOASSAY FOR DETERMINING AFLATOXIN B1 USING A RECOMBINANT PHAGE AS A NONTOXIC COATING CONJUGATE. J Food Saf 2012. [DOI: 10.1111/j.1745-4565.2012.00383.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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9
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Mattes WB, Daniels KK, Summan M, Xu ZA, Mendrick DL. Tissue and species distribution of the glutathione pathway transcriptome. Xenobiotica 2007; 36:1081-121. [PMID: 17118919 DOI: 10.1080/00498250600861793] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The goal of this study was to compare and contrast the basal gene expression levels of the various enzymes involved in glutathione metabolism among tissues and genders of the rat, mouse and canine. The approach taken was to use Affymetrix GeneChip microarray data for rat, mouse and canine tissues, comparing intensity levels for individual probes between tissues and genders. As was hypothesized, the relative expression in liver, lung, heart, kidney and testis varied from gene to gene, with differences of expression between tissues sometimes greater than a 1000-fold. The pattern of differential expression was usually similar between male and female animals, but varied greatly between the three species. Gstp1 appears to be expressed at high levels in male mouse liver, reasonable levels in canine liver, but very low levels in male rat liver. In all species examined, Gstp1 expression was below detectable levels in testis. Gsta3/Yc2 expression appeared high in rodent liver and female canine liver, but not male canine liver. Finally, Mgst1 and Gpx3 expression appeared to be lower in canine heart and testis than seen in rodents. Given the critical role of the glutathione pathway in the detoxification of many drugs and xenobiotics, the observed differences in basal tissue distribution among mouse, rat and canine has far-reaching implications in comparing responses of these species in safety testing.
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Affiliation(s)
- W B Mattes
- Department of Toxicogenomics Services, Gene Logic Inc, Gaithersburg, MD, USA.
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10
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Busbee DL, Norman JO, Ziprin RL. Comparative uptake, vascular transport, and cellular internalization of aflatoxin-B1 and benzo(a)pyrene. Arch Toxicol 1990; 64:285-90. [PMID: 2117431 DOI: 10.1007/bf01972988] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Studies of the uptake of benzo(a)pyrene (BaP) and aflatoxin-B1 (AFB1) after gastric instillation showed that BaP was absorbed via the intestinal lymphatic drainage and transported to the vascular circulation sequestered within lipoproteins in thoracic duct lymph, while AFB1 was absorbed with water soluble compounds into the gastrointestinal venous drainage and was not transported in association with lipoproteins. BaP was taken up into plasma lipoproteins over a broad concentration range, while AFB1 was not sequestered within lipoproteins over the same concentration range. Low density lipoproteins (LDL) facilitated BaP uptake into fibroblasts and impeded BaP uptake into hepatocytes. High density lipoproteins (HDL) facilitated BaP uptake into hepatocytes and impeded BaP uptake into fibroblasts. The uptake of AFB1 into either fibroblasts or hepatocytes was not affected by lipoproteins.
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Affiliation(s)
- D L Busbee
- Department of Anatomy, College of Veterinary Medicine, Texas A&M University, College Station 77843
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11
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Abstract
The development and evaluation of in vitro systems from target organs for preliminary assessments of the potential for systemic toxic effects has been receiving increased attention. This review presents a synopsis of progress made in developing toxicity screens for three common target organs and identifies further work needed for more complete validation.
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Affiliation(s)
- C A Tyson
- SRI International, Menlo Park, California
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12
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Müller N, Petzinger E. Hepatocellular uptake of aflatoxin B1 by non-ionic diffusion. Inhibition of bile acid transport by interference with membrane lipids. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 938:334-44. [PMID: 3126815 DOI: 10.1016/0005-2736(88)90131-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Aflatoxin B1 permeates isolated rat hepatocytes by non-ionic diffusion. Its uptake is neither saturable nor influenced by metabolic energy and not inhibited by treatment of cells with proteases. The initial rate of aflatoxin B1 uptake measured at 7 degrees C is between 40 and 50% compared to that at 37 degrees C. However, after an incubation period of 7 minutes identical equilibrium uptake is reached at both temperatures. The apparent activation energies, calculated for aflatoxin B1 uptake by Arrhenius diagrams ranged between 1.69 and 4.5 kcal/mol. A Q10 value of 1.34 was calculated for a temperature interval of 7-17 degrees C but decreased to 1.05 for the interval of 27-37 degrees C. Liposomes or lipoproteins added to the cell suspension inhibited the aflatoxin B1 uptake into hepatocytes. Liposomes mainly composed of unsaturated fatty acids bind twice as much aflatoxin B1 as those composed of saturated ones, indicating that the lipophilicity of the mycotoxin is crucial in the determination of its uptake into liver cells. At concentrations above 5 micrograms/ml, aflatoxin B1 inhibited the carrier-mediated uptake of cholic acid and of phalloidin into hepatocytes. This effect was reversible and abolished by washing the cells after preincubation with aflatoxin. In concentrations below 5 micrograms/ml the uptake of phallotoxin and cholic acid was however stimulated by 15-25%. These results indicate, that a carrier-mediated uptake into hepatocytes via the multispecific bile salt transporter is not responsible for the organoselective clearance of aflatoxins by the liver. On the other hand, the cholestatic effect of aflatoxin B1 results at least partially from the inhibition of the multispecific bile acid transport system. This inhibition may arise from affinity of aflatoxins to lipid domains of the cell membrane.
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Affiliation(s)
- N Müller
- Institut für Pharmakologie und Toxikologie, Justus Liebig Universität Giessen, F.R.G
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13
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Madle E, Korte A, Beek B. Species differences in mutagenicity testing: I. Micronucleus and SCE tests in rats, mice, and Chinese hamsters with aflatoxin B1. TERATOGENESIS, CARCINOGENESIS, AND MUTAGENESIS 1986; 6:1-13. [PMID: 2874633 DOI: 10.1002/tcm.1770060102] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Three animal species used in in vivo mutagenicity testing--rats, mice and Chinese hamsters--were compared with respect to their mutagenic response to the mycotoxin aflatoxin B1 (AFB1). The micronucleus test and the SCE test with bone marrow cells were chosen as test methods, employing similar protocols for all species. The mutagenic potential of AFB1 was detected with rats and mice but not with Chinese hamsters. Rats were more susceptible to the mutagenic action of AFB1 than mice with regard to the effective dose. A difference in sensitivity between males and females was evident in rats and mice: male animals exhibited higher induced micronucleus frequencies than females, and a clear SCE-inducing effect was only detectable in male animals. These results are in agreement with those of in vitro and carcinogenicity studies. They may be due to metabolic differences between the species and sexes, predominantly differences in glutathione conjugation of the reactive AFB1 epoxide and in the formation of the metabolite aflatoxicol. Furthermore, it could be demonstrated that AFB1 seems to be a more potent inducer of micronuclei than of SCE. Since our results obtained with rats and mice were clearly positive, but with the Chinese hamster the mutagenic potential of AFB1 was not detectable with the test systems used, it can be concluded that the choice of an "inappropriate" test species may lead to a false negative judgment on the genotoxic potential of a test compound.
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Mohapatra NK, Roberts JF. In vitro effect of aflatoxin B1 on rat liver macrophages (Kuffer cells). Toxicol Lett 1985; 29:177-81. [PMID: 2418540 DOI: 10.1016/0378-4274(85)90039-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The effect of aflatoxin B1 on the uptake and incorporation of [3H]leucine and [3H]uridine and on phagocytosis of latex particles was studied using cultures of rat liver macrophages (Kuffer cells). Aflatoxin B1 inhibited the incorporation of both isotopes, but inhibition of uridine incorporation was greater than that of leucine, suggesting that RNA synthesis was a major site of inhibition. Aflatoxin B1 also inhibited phagocytosis of latex particles in a time- and dose-dependent manner.
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