Congestive Preconditioning by Portal Venous Clamping: A Novel Preventive Concept for Small Intestinal Congestive Re-Outflow Injury.

BACKGROUND Congestion of the small intestine, which induces mucosal damage via apoptosis, is a common pathophysiological change in hepato-biliary-pancreatic surgery, including liver transplantation. Small intestinal mucosal damage can trigger postoperative complications via various pathways. Therefore, we investigated the efficacy of intermittent portal venous clamping, which we named congestive preconditioning (CPC), for decreasing congestive re-outflow injury (CRoI) of the small intestine. MATERIAL AND METHODS Small intestinal CRoI was induced in rats by clamping the portal vein (PV) for 30 min, followed by re-outflow. The CPC group underwent 3 episodes of 5 min PV clamping and 5 min re-outflow before CRoI. The Control group underwent CRoI after 30 min simple laparotomy without any preconditioning. Survival and histological changes in the small intestine after CRoI were analyzed. The histological changes were compared CPC group to Control group using a scoring system that expressed histopathological severity. Also, small intestinal apoptosis and expression of apoptosis-related genes were analyzed by immunohistochemistry. RESULTS The survival rate of the CPC group was significantly higher than Control group. Histological scoring of small intestinal damage was significantly lower in the CPC group after 6 h of CRoI. Expression of anti-apoptotic gene, Bcl-xL was significantly increased, but pro-apoptotic gene caspase-3 and apoptotic cells did not differ significantly between the CPC group and Control group. CONCLUSIONS Induction of CPC for small intestinal CRoI was effective, which suggests that an anti-apoptotic pathway is involved in the beneficial mechanism.