Increased gut permeability to fluorescein isothiocyanate-dextran after total parenteral nutrition in the rat

Sepsis with subsequent multiple organ failure is the commonest complication seen in the surgical intensive care unit today. A gut mucosal barrier dysfunction is assuming an increasingly important role as one possible explanation for the initiation of the septic process. It is known that the gut bacteria and endotoxins can, in the presence of a seemingly intact epithelium, translocate to extraintestinal sites, but the exact mechanism behind this process is not understood. In the present study we have approached this problem by testing the gut permeability to two macromolecules, bovine serum albumin (BSA) and fluorescein isothiocyanate (FITC)-dextran, after 7 days of enteral or parenteral nutrition in the rat. The plasma values of FITC-dextran after 4 h of marker feeding showed a significant increase in gut permeability after parenteral but not after enteral nutrition as compared with the controls. The plasma values of BSA, however, did not show any significant change in any of the groups. Thus, parenteral nutrition, with the changes occurring in the gut mucosa, may be one of the etiologic co-factors behind a gut mucosal barrier dysfunction, eventually leading to absorption of noxious agents into the systemic circulation with subsequent multiple organ failure.