Enterotoxic effect of the vacuolating toxin produced by Helicobacter pylori in Caco-2 cells |
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Authors: | A Guarino M Bisceglia RB Canani MC Boccia G Mallardo E Bruzzese P Massari R Rappuoli J Telford |
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Affiliation: | Department of Pediatrics, University Federico II, Naples, Italy. alfguari@cds.unina.it |
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Abstract: | Preliminary clinical evidence suggests that Helicobacter pylori may be associated with diarrhea through its vacuolating toxin (VacA). To establish whether VacA induces intestinal secretion, epithelial damage, or both, purified pH-activated VacA was added to Caco-2 cell monolayers mounted in Ussing chambers, and electrical parameters were monitored. Mucosal addition of VacA induced an increase in short circuit current, consistent with enterotoxic effect. The effect was time- and dose-dependent and saturable. It was not found if the toxin was not pH-activated, added to the serosal side, or preheated. In cells preloaded with the Ca2+ buffering compound BAPTA/AM or with the Cl- channel inhibitor 5-nitro-2-3-(3-phenylpropylamino)benzoic acid, short circuit current did not change, indicating that VacA induces activation of Ca2+-dependent Cl- channels. VacA did not show cytopathic effects, as judged by tissue resistance. These results support the hypothesis that H. pylori may be associated with diarrhea through production of VacA. |
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