Gut Origin Sepsis, Macrophage Function, and Oxygen Extraction Associated with Acute Pancreatitis in the Rat

Abstract

It has been suggested that the gut plays a role in the development of bacterial complications, which are important contributors to morbidity and mortality in patients with acute pancreatitis. The present study evaluated the enteric bacterial translocation, bacterial homeostasis, and reticuloendothelial system function in experimental acute pancreatitis induced by intraductal injection of 5% sodium taurodeoxycholate in the rat. The incidence of bacterial translocation from the gut to mesenteric lymph nodes (MLNs) and lungs significantly increased after 12 hours and to the systemic circulation, ascites, and pancreas at 24 hours. The number of anaerobic bacteria and lactobacilli decreased in the colon and distal ileum from 6 or 12 hours, whereas the number of Escherichia coli increased from 12 hours. The systemic uptake rate of radiolabeled bacteria decreased from 6 hours after induction of acute pancreatitis. The uptake of radiolabeled bacteria by Kupffer cells decreased from 6 hours, whereas the uptake by macrophages from blood, lungs, and the intestine increased. A decrease in macrophage killing capacity was noted, reflected by an increase in the number of cultured viable bacteria from isolated macrophages. The whole-body oxygen extraction rate increased 4 to 24 hours after induction of pancreatitis, whereas the gut oxygen extraction rate decreased at 2 and 4 hours, followed by an increase at 12 to 24 hours. These data show that translocation of enteric bacteria occurs during the early stage of acute pancreatitis and that the MLN–thoracic duct–circulation may be a major route of bacterial dissemination. Compromised gut oxygen metabolism, overexaggerated intestinal macrophages, and impaired host immune function may be involved in the development of infectious complications associated with acute pancreatitis.