Arch Toxicol DOI 10.1007/s00204-015-1546-1
TOXICOKINETICS AND METABOLISM
Impact of dextran sulphate sodium‑induced colitis on the intestinal transport of the colon carcinogen PhIP Petra Nicken1 · Anne von Keutz1 · Ina Willenberg1 · Annika I. Ostermann1 · Nils Helge Schebb1,2 · Samoa Giovannini3 · Olivia Kershaw3 · Gerhard Breves4 · Pablo Steinberg1
Received: 11 February 2015 / Accepted: 3 June 2015 © Springer-Verlag Berlin Heidelberg 2015
Abstract Colorectal cancer is one of the most frequent cancers in Western countries. Chronic intestinal diseases such as Crohn’s disease and ulcerative colitis, in which the intestinal barrier is massively disturbed, significantly raise the risk of developing a colorectal tumour. 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a genotoxic heterocyclic aromatic amine that is formed after strongly heating fish and meat. In this study, the hypothesis that PhIP uptake in the gut is increased during chronic colitis was tested. Chronic colitis was induced by oral administration of dextran sulphate sodium (DSS) to Fischer 344 rats. The transport of PhIP in eight different rat intestinal segments was examined in Ussing chambers. The tissues were incubated with 10 µM PhIP for 90 min, and the concentration of PhIP was determined in the mucosal and serosal compartments of the Ussing chambers as well as in the clamped tissues by LC-MS. Although chronic colitis was clearly induced in the rats, no differences in the intestinal transport of PhIP were observed between control and DSS-treated animals. The hypothesis that in the course of chronic colitis more PhIP is taken up by the intestinal
* Pablo Steinberg pablo.steinberg@tiho‑hannover.de 1
Institute for Food Toxicology and Analytical Chemistry, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173 Hannover, Germany
2
Institute of Food Chemistry, University of Wuppertal, 42119 Wuppertal, Germany
3
Department of Veterinary Pathology, Freie Universität Berlin, 14163 Berlin, Germany
4
Department of Physiology, University of Veterinary Medicine Hannover, Foundation, 30173 Hannover, Germany
epithelium, thereby increasing the risk of developing colorectal cancer, could not be confirmed in the present report. Keywords 2-Amino-1-methyl-6-phenylimidazo[4,5-b] pyridine · Chronic colitis · Colorectal cancer · Dextran sulphate sodium · Heterocyclic aromatic amines · Ussing chamber
Introduction In Western countries, colorectal cancer is a major cause of death (Siegel et al. 2011). Obese people, smokers and alcohol consumers, as well as patients suffering from chronic intestinal inflammatory diseases (IBD) such as Crohn’s disease and ulcerative colitis are at a higher risk of developing a colorectal tumour (Janakiram and Rao 2014). The incidence of colorectal cancer correlates with the consumption of well-done meat (Chao et al. 2005; Norat et al. 2005; Cross et al. 2010). During the cooking of meat at high temperatures for a long time or over an open fire, heterocyclic aromatic amines (HCAs) are formed (Shioya et al. 1987). The most abundantly formed HCA is 2-amino-1-methyl6-phenylimidazo[4,5-b]pyridine (PhIP) (Layton et al. 1995). The International Agency for Research on Cancer (IARC) classified PhIP as a carcinogen in the category 2B (i.e. possibly carcinogenic to humans). Following its metabolic activation, PhIP forms DNA adducts and is mutagenic in bacterial as well as mammalian cell-based genotoxicity assays (Thompson et al. 1987; Frandsen et al. 1992; Schut and Herzog 1992; Friesen et al. 1994; Dragsted et al. 1995). PhIP induces carcinomas in the large intestine of rats (Ito et al. 1991; Hasegawa et al. 1993), but the PhIP doses fed in these studies (100–400 ppm) were very high and far beyond the human-relevant PhIP dose range
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TOXICOKINETICS AND METABOLISM
Impact of dextran sulphate sodium‑induced colitis on the intestinal transport of the colon carcinogen PhIP Petra Nicken1 · Anne von Keutz1 · Ina Willenberg1 · Annika I. Ostermann1 · Nils Helge Schebb1,2 · Samoa Giovannini3 · Olivia Kershaw3 · Gerhard Breves4 · Pablo Steinberg1
Received: 11 February 2015 / Accepted: 3 June 2015 © Springer-Verlag Berlin Heidelberg 2015
Abstract Colorectal cancer is one of the most frequent cancers in Western countries. Chronic intestinal diseases such as Crohn’s disease and ulcerative colitis, in which the intestinal barrier is massively disturbed, significantly raise the risk of developing a colorectal tumour. 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a genotoxic heterocyclic aromatic amine that is formed after strongly heating fish and meat. In this study, the hypothesis that PhIP uptake in the gut is increased during chronic colitis was tested. Chronic colitis was induced by oral administration of dextran sulphate sodium (DSS) to Fischer 344 rats. The transport of PhIP in eight different rat intestinal segments was examined in Ussing chambers. The tissues were incubated with 10 µM PhIP for 90 min, and the concentration of PhIP was determined in the mucosal and serosal compartments of the Ussing chambers as well as in the clamped tissues by LC-MS. Although chronic colitis was clearly induced in the rats, no differences in the intestinal transport of PhIP were observed between control and DSS-treated animals. The hypothesis that in the course of chronic colitis more PhIP is taken up by the intestinal
* Pablo Steinberg pablo.steinberg@tiho‑hannover.de 1
Institute for Food Toxicology and Analytical Chemistry, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173 Hannover, Germany
2
Institute of Food Chemistry, University of Wuppertal, 42119 Wuppertal, Germany
3
Department of Veterinary Pathology, Freie Universität Berlin, 14163 Berlin, Germany
4
Department of Physiology, University of Veterinary Medicine Hannover, Foundation, 30173 Hannover, Germany
epithelium, thereby increasing the risk of developing colorectal cancer, could not be confirmed in the present report. Keywords 2-Amino-1-methyl-6-phenylimidazo[4,5-b] pyridine · Chronic colitis · Colorectal cancer · Dextran sulphate sodium · Heterocyclic aromatic amines · Ussing chamber
Introduction In Western countries, colorectal cancer is a major cause of death (Siegel et al. 2011). Obese people, smokers and alcohol consumers, as well as patients suffering from chronic intestinal inflammatory diseases (IBD) such as Crohn’s disease and ulcerative colitis are at a higher risk of developing a colorectal tumour (Janakiram and Rao 2014). The incidence of colorectal cancer correlates with the consumption of well-done meat (Chao et al. 2005; Norat et al. 2005; Cross et al. 2010). During the cooking of meat at high temperatures for a long time or over an open fire, heterocyclic aromatic amines (HCAs) are formed (Shioya et al. 1987). The most abundantly formed HCA is 2-amino-1-methyl6-phenylimidazo[4,5-b]pyridine (PhIP) (Layton et al. 1995). The International Agency for Research on Cancer (IARC) classified PhIP as a carcinogen in the category 2B (i.e. possibly carcinogenic to humans). Following its metabolic activation, PhIP forms DNA adducts and is mutagenic in bacterial as well as mammalian cell-based genotoxicity assays (Thompson et al. 1987; Frandsen et al. 1992; Schut and Herzog 1992; Friesen et al. 1994; Dragsted et al. 1995). PhIP induces carcinomas in the large intestine of rats (Ito et al. 1991; Hasegawa et al. 1993), but the PhIP doses fed in these studies (100–400 ppm) were very high and far beyond the human-relevant PhIP dose range
13
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