title: Potential of an in vitro toolbox combined with exposure data as a first step for the risk assessment of dietary chemical contaminants.
abstract: In vitro risk assessment of dietary contaminants has become a priority in human food safety. This paper proposes an in vitro approach associating different complementary tools in an original toolbox and aims to improve the assessment of the toxicological impact of dietary contaminants at realistic human exposure levels, with a special focus on the intestinal compartment. The system is based on the use of four complementary cellular tools, namely stress gene induction in transgenic strains of Escherichia coli, modulation of the activity of key biotransformation enzymes (cytochrome P-450 (CYP) 1A1 and 3A4) in a human intestinal cell line, and activation of aryl hydrocarbon receptor (AhR) and oestrogenic receptor (ER)-dependent genes in agonistic and antagonistic assays with luciferase reporter cells. It was applied to four chosen model molecules: ochratoxin A (OTA) and deoxynivalenol (DON), two common food-borne mycotoxins, and imazalil (IMA) and benomyl (BEN), two fungicides widely occurring in foodstuffs. All these assays were performed at or around a realistic intestinal concentration, determined through a deterministic approach based on the calculation of a theoretical maximum daily intake (TMDI). Using the four model molecules, it is clearly highlighted that induction of CYP1A1 activity and inhibition of CYP3A4 activity occurred in Caco-2 cells at a realistic intestinal concentration of IMA. Furthermore, some bacterial stress genes were induced in a range of realistic concentrations, following exposure to DON and IMA. In addition, BEN clearly provoked an ER agonistic activity in a human oestrogen sensitive reporter cell line. All these results are in accordance with the literature, suggesting that the in vitro toolbox constitutes an interesting approach in order to obtain a first 'fingerprint' of dietary contaminants at realistic human exposure for further risk assessment.
authors.affiliation: Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 2/8 and 5/3, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: L
authors.initials: L
authors.lastname: Ribonnet
authors.forename: E
authors.initials: E
authors.lastname: van der Heiden
authors.forename: I
authors.initials: I
authors.lastname: Nobels
authors.forename: A
authors.initials: A
authors.lastname: Chaumont
authors.forename: A-S
authors.initials: AS
authors.lastname: Remacle
authors.forename: S
authors.initials: S
authors.lastname: De Saeger
authors.forename: Y-J
authors.initials: YJ
authors.lastname: Schneider
authors.forename: M-L
authors.initials: ML
authors.lastname: Scippo
authors.forename: R
authors.initials: R
authors.lastname: Blust
authors.forename: L
authors.initials: L
authors.lastname: Pussemier
authors.forename: Y
authors.initials: Y
authors.lastname: Larondelle
mesh_terms: D000818:Animals; D001542:Benomyl / Q000633:toxicity; D045744:Cell Line, Tumor; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D005504:Food Analysis / Q000379:methods*; D005506:Food Contamination; D005659:Fungicides, Industrial / Q000633:toxicity; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007093:Imidazoles / Q000633:toxicity*; D009793:Ochratoxins / Q000633:toxicity*; D030781:Organisms, Genetically Modified; D051381:Rats; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism; D018570:Risk Assessment; D013312:Stress, Physiological; D014255:Trichothecenes / Q000633:toxicity*
chemical_list: D005659:Fungicides, Industrial; D007093:Imidazoles; D009793:Ochratoxins; D011960:Receptors, Estrogen; D014255:Trichothecenes; C025589:ochratoxin A; C017435:enilconazole; D003577:Cytochrome P-450 Enzyme System; C007262:deoxynivalenol; D001542:Benomyl