Heat shock protein 72 normothermic ischemia, and the impact of congested portal blood reperfusion on rat liver.

Abstract

From the technical aspect of liver surgery, control of bleeding during hepatic parenchymal resection is one of the most important procedures in hepatectomy. Pringle's maneuver, a temporary cross-clamping of the hepatoduodenal ligament, has often been used for this purpose[1]. This is the simplest and useful technique to reduce intraoperative blood loss. Unfortunately, this method has resulted in normothermic ischemia-reperfusion injury of the liver. Many clinical observations indicate that prolonged intraoperative normothermic ischemia and succeeding reperfusion of the liver are the most significant disadvantages of Pringle's manever, and may cause postoperative functional disorder of the liver[2-6]. Although the process of ischemia-reperfusion injury of the liver is complicated, it consists of three pathologic components: hepatic ischemia, portal congestion, and reinflow of arterial and congested portal blood. Ischemia-reperfusion injury is not merely an ischemic injury but is also related to reperfusion of blood. Moreover, it has been revealed that reactive oxygen radicals and some chemical mediators activated during recirculation play an important role in the development of liver injury after ischemia[7-11]. Because portal congestion is an extremely harmful factor that can induce bacterial translocation, generation of chemical mediators, and reactive oxygen radicals in the portal flow, it is conceivable that reinflow of congested portal blood containing activated pathogens may play a role in the development of ischemia-reperfusion injury of the liver. However, the influence of portal congestion on the development of liver injury during ischemia-reperfusion injury has not been well researched. Only a few authors have described the significance of the reperfusion of congested portal blood[12]. Heat shock protein 72 (HSP72) is produced in the liver after normothermic ischemia and reperfusion[13-15]. HSP72 is now being intensively investigated as one of the most fundamental stress proteins. The protein is produced in response to a variety of stress-induced stimuli and is considered to be an important factor which helps to maintain cellular homeostasis and increase the chance of pateint survival[16-23]. In the present study, we investigated the induction of HSP72 in the liver tissue after 15-min Pringle's maneuver with or without portosystemic shunt in the rat model, to determine the influence of congested portal blood on the development of ischemia-reperfusion injury in liver.