TNF is a key mediator in sepsis‐induced intestinal barrier dysfunction but is independent of enterocyte NFκB

Inhibition of enterocyte NFκB augments sepsis‐induced intestinal hyperpermeability, gut apoptosis, and TNF expression. We hypothesized that TNF is a key mediator of gut barrier dysfunction and apoptosis in sepsis. Mice lacking enterocyte IKKβ (resultant NFκB inhibition) were created via Cre/lox recombination under control of the villin promoter. Wildtype (WT) and Vil ‐Cre/Ikkβ F/Ä (IKKβ −/− ) mice were injected 3 hr pre‐operatively with monoclonal anti‐TNF antibody or isotype control followed by cecal ligation and puncture (n=5–12/group). At 24 hr, intestinal permeability was assessed in vivo using FD4. Apoptosis was evaluated in crypts by active caspase‐3 staining. Blood was harvested for bacterial cultures. Anti‐TNF decreased permeability in septic WT (1832±321 vs. 4678±421 ng/ml; p<0.001) and septic IKKβ −/− mice (2528±446 vs. 6650±951 ng/ml; p<0.01). Sepsis‐induced apoptosis was decreased in both anti‐TNF treated septic WT (13±1 vs. 4±2; p<0.05) and septic IKKβ −/− mice (20±2 vs. 4±1; p<0.001). Anti‐TNF decreased bacteremia in septic WT (4×10 3 ±2×10 3 vs. 4×10 5 ±3×10 5 CFU/ml; p<0.05) and septic IKKβ −/− mice (500±500 vs. 3×10 6 ±2×10 6 CFU/ml; p<0.01). There were no differences between anti‐TNF treated groups for any parameter. TNF appears to be a key mediator in sepsis‐induced intestinal barrier dysfunction. However, this mechanism is independent of enterocyte NFκB. NIH GM66202 & GM082008.