title: An investigation of the effect of gastrointestinal microbial activity on oral arsenic bioavailability.
abstract: In vitro gastrointestinal (GI) microbial activity in the colon compartment facilitates the arsenic release from soils into simulated GI fluids. Consequentially, it is possible that in vitro models that neglect to include microbial activity underestimate arsenic bioaccessibility when calculating oral exposure. However, the toxicological relevance of increased arsenic release due to microbial activity is contingent upon the subsequent absorption of arsenic solubilized in the GI lumen. The objectives of this research are to: (1) assess whether microbes in the in vitro small intestine affect arsenic solubilization from soils, (2) determine whether differences in the GI microbial community result in differences in the oral bioavailability of soil-borne arsenic. In vitro GI microbial activity in the distal small intestine increased arsenic release from soils; however, these effects were unlikely to be relevant since they were transient and demonstrated small effect sizes. In vivo arsenic absorption for juvenile swine was unaffected by antibiotic treatment. Therefore, it appears that microbial effects on arsenic release do not result in increased arsenic bioavailability. However, it remains to be seen whether the results for the limited set of soils described herein can be extrapolated to arsenic contaminated sites in general.
authors: University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors: Brian D
authors: BD
authors: Laird
authors: Kyle J
authors: KJ
authors: James
authors: Tom R
authors: TR
authors: Van de Wiele
authors: Matt
authors: M
authors: Dodd
authors: Stan W
authors: SW
authors: Casteel
authors: Mark
authors: M
authors: Wickstrom
authors: Steven D
authors: SD
authors: Siciliano
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use; D001151:Arsenic / Q000493:pharmacokinetics* / Q000652:urine; D001682:Biological Availability; D016000:Cluster Analysis; D003198:Computer Simulation; D041981:Gastrointestinal Tract / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008954:Models, Biological; D012989:Soil Pollutants / Q000493:pharmacokinetics* / Q000652:urine; D013552:Swine
chemical_list: D000900:Anti-Bacterial Agents; D012989:Soil Pollutants; D001151:Arsenic