Oral exposure to PAH: bioactivation processes in the human gut

摘要

We used the Simulator of the Human Intestinal Microbial Ecosystem (SHIME) to perform in vitro stomach, small intestine and colon digestion experiments on polycyclic aromatic hydrocarbons (PAH) as pure compounds or from contaminated environmental samples entering the gastrointestinal tract. To screen for possible toxicological aspects, two yeast bioassays were used on the digests. Binding of PAHs to the human aryl hydrocarbon receptor (hAR) and binding of probable PAH biotransformation products to the human estrogen receptor (hER) was evaluated in the aryl yeast and estrogen yeast assay, respectively. Upon incubation with colon microbiota, positive signals in the estrogen receptor test were observed. PAHs as such are not estrogenic, leading to our hypothesis that biotransformation reactions had occurred during incubation with colon micro-biota in the SHIME reactor. The production of intermediates that have already been described to have estrogenic or genotoxic properties, was confirmed by the detection of 1-hydroxypyrene and 7-hydroxybenzo(a)pyrene using LC-ESI-MS.