Alterations of epithelial permeability by Helicobacter and IL-1 beta in vitro - Protective effect of rebamipide

Infection with Helicobacter increases the transcellular passage of macromol ecules across the epithelium, and this effect can be prevented by a gastrop rotective agent rebamipide, The aim was to gain insight into the mechanisms involved. The HT29-19A intestinal epithelial cells grown on microporous fi lters as monolayers were incubated in the presence or absence of rebamipide (1 or 2 mM) with: (1) suspension of a wild H. pylori strain, (2) IL-1 beta (0.5 ng/ml) + IFN-gamma (2 units/ml). After incubation, the monolayers wer e submitted to evaluation of apoptosis by using the apoptotic cell death de tection ELISA kit and to assessment of epithelial permeability in Ussing ch amber where the ionic conductance (G), fluxes of mannitol (J(Man)) and of h orseradish peroxidase in both intact (J(HRPi))- and degraded (J(D)) form, w ere measured. H, pylori increased the intact HRP fluxes across the barrier (J(HRPi) = 17 +/- 20 vs 97 +/- 70 ng/hr/cm, P < 0.007), an effect prevented by rebamipide (J(HRPi) 33 +/- 34 ng/hr/cm(2), P < 0.006). IL-1 beta increa sed the ionic conductance (G = 5.5 +/- 1.0 and 21.0 +/- 7.0 mS/cm(2), P < 0 .006), the intact HRP fluxes (J(HRPi) = 18 +/- 15 and 476 +/- 344 ng/hr/cm( 2), P < 0.006), and the apoptotic index of the cells (AI = 1 +/- 0 vs 3.7 /- 0.8), all effects prevented by rebamipide (G = 12 +/- 4.9 mS/cm(2), J(HR Pi) = 79 +/- 38, AI = 1.6 +/- 0.6, P < 0.03 as compared to IL-beta -treated cells). In basal conditions, rebamipide increased the integrity of the bar rier (G = 7.5 +/- 2.3 vs 6.0 +/- 1.8 mS/cm(2) for controls, P < 0.007). In conclusion, H. pylori as well as IL-1 beta, may alter epithelial permeabili ty and rebamipide may exert its protective effect on gastric mucosa by rein forcing the epithelial barrier in normal conditions and by counteracting th e deleterious effect of Helicobacter pylori and IL-1 beta on macromolecular permeability.