Total parenteral nutrition and bowel rest result in change of cecal flora but no increased bacterial translocation

The etiology of hepatic complications due to total parenteral nutrition (TPN) is poorly understood. Recently, bacterial translocation and the release of a hepatotoxic substance were considered as possible etiology of TPN-associated liver function derangement. We studied bacterial translocation in mesenteric lymph nodes, liver and spleen; cecal flora; and liver fat, cholesterol and triglycerides in 28 rats with implanted intravenous catheters receiving either glucose-based TPN or normal rat chow for 7-9 days. No bacterial translocation or liver function derangements were detected in normal free-feeding controls or following a 72 hour fast. Despite similar rates of bacterial translocation in the TPN and free-feeding groups we detected a significantly increased (p < 0.001) accumulation of fat, triglycerides and cholesterol in liver tissue of TPN rats. Cultures of the cecum revealed significantly (p < 0.01) increased concentrations of aerobic and facultative anaerobic Gram negative bacteria in TPN rats compared with controls. It thus seems as if translocation cannot explain the liver function derangement during TPN, which can, however, be explained by the abundance of Gram negative bacteria in the cecum of TPN rats. this overgrowth of Gram negative bacteria might be responsible for the release of a hepatoxic substance like endotoxin or possibly TNF.