RT Journal Article SR Electronic T1 Bacteroides fragilis toxin 2 damages human colonic mucosa in vitro JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 504 OP 510 DO 10.1136/gut.44.4.504 VO 44 IS 4 A1 M Riegler A1 M Lotz A1 C Sears A1 C Pothoulakis A1 I Castagliuolo A1 C C Wang A1 R Sedivy A1 T Sogukoglu A1 E Cosentini A1 G Bischof A1 W Feil A1 B Teleky A1 G Hamilton A1 J T LaMont A1 E Wenzl YR 1999 UL http://gut.bmj.com/content/44/4/504.abstract AB BACKGROUND Strains ofBacteroides fragilis producing a 20 kDa protein toxin (B fragilis toxin (BFT) or fragilysin) are associated with diarrhoea in animals and humans. Although in vitro results indicate that BFT damages intestinal epithelial cells in culture, the effects of BFT on native human colon are not known.AIMS To examine the electrophysiological and morphological effects of purified BFT-2 on human colonic mucosa in vitro.METHODS For resistance (R) measurements, colonic mucosa mounted in Ussing chambers was exposed to luminal or serosal BFT-2 (1.25–10 nM) and after four hours morphological damage was measured on haematoxylin and eosin stained sections using morphometry. F actin distribution was assessed using confocal microscopy.RESULTS Serosal BFT-2 for four hours was four-, two-, seven-, and threefold more potent than luminal BFT-2 in decreasing resistance, increasing epithelial3H-mannitol permeability, and damaging crypt and surface colonocytes, respectively (p<0.05). Confocal microscopy showed reduced colonocyte F actin staining intensity after exposure to BFT-2.CONCLUSIONS BFT-2 increases human colonic permeability and damages human colonic epithelial cells in vitro. These effects may be important in the development of diarrhoea and intestinal inflammation caused by B fragilis in vivo.BFTBacteroides fragilis toxinETBFenterotoxigenicBacteroides fragilisIscshort circuit currentPDpotential differenceRresistance