Endotoxin-transport routes and kinetics in intestinal ischemia

A rat model representing segmental intestinal ischemia was used to study the absorption and transport of endotoxin from the ischemic gut. Serial quantitative analyses were made on peritoneal fluid, thoracic duct lymph and arterial and portal vein blood. Significantly increased endotoxin concentrations were found in thoracic duct lymph before transmural leakage took place. After leaking through the devitalized intestinal wall, endotoxin was transported by both lymphatic and portal routes. Kinetic analysis revealed that systemic endotoxemia paralleled the appearance of endotoxins in thoracic duct lymph, preceding a significant increase in the portal vein. The amount transported by the portal vein never exceeded the proposed endotoxin-filtrating capacity of the liver. In intestinal ischemia, consequently, systemic endotoxemia appears to be mediated mainly by lymphatic transport.