Irene H. Straatsburg

Decrease in core liver temperature with 10°C by in situ hypothermic perfusion under total hepatic vascular exclusion reduces liver ischemia and reperfusion injury during partial hepatectomy in pigs

OBJECTIVE We attempted to assess liver ischemia/reperfusion injury under a mild decrease in core liver temperature of 10 degrees C by in situ hypothermic perfusion during ischemia. METHODS Liver ischemia was induced in pigs by total hepatic vascular exclusion with concomitant in situ perfusion with hypothermic (4 degrees C) Ringer-glucose (cold perfused group, core liver temperature maintained at 28 degrees C), with normothermic (38 degrees C) Ringer-glucose (warm perfused group) or without in situ perfusion (control group). RESULTS In the cold perfused, warm perfused, and control groups, 24-hour survival was 5/5, 0/5, and 3/5, respectively. Hemodynamic parameters in the cold perfused group remained stable, whereas pigs in both other groups required circulatory support. Plasma AST and interleukin-6 levels were lower in the cold perfused group than in both other groups. Hepatocellular function was best preserved in the cold perfused group as indicated by complete recovery of bile production during reperfusion and no loss of indocyanine green clearance capacity. In both other groups, bile production and indocyanine green clearance capacity were reduced significantly. The hyaluronic acid uptake capacity of pigs in the cold perfused group or control group did not differ, indicating preserved sinusoidal endothelial cell function. Histopathologic injury scores during reperfusion were significantly lower in the cold perfused group when compared to both other groups. CONCLUSIONS A mild decrease in core liver temperature of 10 degrees C by in situ hypothermic liver perfusion during ischemia protects the liver from ischemia/reperfusion injury. This protection appears to be related to cooling of the liver rather than to the washout of blood during perfusion.

Evaluation of rat liver apoptotic and necrotic cell death after cold storage using Uw, Htk, and celsior

Background. The benefit of Celsior in liver graft preservation is controversial. In the isolated perfused rat liver model, we compared the effects of Celsior, University of Wisconsin (UW), and histidine-tryptophan-ketoglutarate (HTK) preservation solutions on liver cell death. Methods. Rat livers were stored at 4°C for 0, 8, 16, or 24 hr in either Celsior, UW, or HTK and reperfused for 90 min (37°C). Bile secretion and perfusate levels of liver enzymes and histone-associated DNA fragments were measured. Apoptosis and oncotic necrosis were analyzed in biopsies by DNA gel electrophoresis, hematoxylin and eosin histology, and enzyme histochemistry for lactate dehydrogenase (LDH) and 5′-nucleotidase (5′-NT). Results. Perfusate flow rate through the liver during perfusion did not significantly differ among preservation solutions. Bile secretion was best preserved in UW livers after 16-hr (versus HTK livers) and 24-hr storage (versus HTK and Celsior livers). Enzyme leakage from UW livers was lower compared with HTK livers after 8-hr storage (serum glutamic oxaloacetic transaminase [SGOT], LDH) and with Celsior and HTK livers after 16-hr (SGOT, LDH) and 24-hr storage (SGOT, serum glutamic pyruvic transaminase, LDH, purine nucleoside phosphorylase). In situ LDH and 5′-NT activities were best preserved in UW livers (up to 24 hr), whereas enzyme activities declined remarkably in HTK livers (after 8 hr) and Celsior livers (after 16 hr of cold storage). Although perfusate DNA fragment levels were repeatedly lowest from Celsior livers, apoptotic DNA laddering and the number of fragmented nuclei in hematoxylin and eosin sections was not different among livers after 8, 16, or 24 hr of storage. Conclusions. Celsior and UW are equally effective in preventing rat liver cell death after 0–16 hr of cold preservation as compared with the less effective HTK solution. After 24-hr cold storage, rat livers were best preserved in UW. Furthermore, there was no significant difference in mode of cell death (apoptosis or oncotic necrosis) after storage in any of the three solutions.

Lesion progression with time and the effect of vascular occlusion following radiofrequency ablation of the liver

The effectiveness of radiofrequency ablation (RFA) under selective vascular occlusion and its effects on architecture and viability of normal liver parenchyma was studied in a porcine model.

Inhibition of classical complement activation attenuates liver ischaemia and reperfusion injury in a rat model.

Activation of the complement system contributes to the pathogenesis of ischaemia/reperfusion (I/R) injury. We evaluated inhibition of the classical pathway of complement using C1‐inhibitor (C1‐inh) in a model of 70% partial liver I/R injury in male Wistar rats (n = 35). C1‐inh was administered at 100, 200 or 400 IU/kg bodyweight, 5 min before 60 min ischaemia (pre‐I) or 5 min before 24 h reperfusion (end‐I). One hundred IU/kg bodyweight significantly reduced the increase of plasma levels of activated C4 as compared to albumin‐treated control rats and attenuated the increase of alanine aminotransferase (ALT). These effects were not better with higher doses of C1‐inh. Administration of C1‐inh pre‐I resulted in lower ALT levels and higher bile secretion after 24 h of reperfusion than administration at end‐I. Immunohistochemical assessment indicated that activated C3, the membrane attack complex C5b9 and C‐reactive protein (CRP) colocalized in hepatocytes within midzonal areas, suggesting CRP is a mediator of I/R‐induced, classical complement activation in rats. Pre‐ischaemic administration of C1‐inh is an effective pharmacological intervention to protect against liver I/R injury.

Experimental Model of Obstructive, Chronic Pancreatitis in Pigs

Background: We aimed to develop a reproducible, experimental model of obstructive pancreatitis for future analysis of surgical interventions, and characterized this model using functional, histological and biochemical parameters. Animals and Methods: In 10 female pigs the pancreatic duct (PD) was ligated. After 4, 6 or 8 weeks the animals were sacrificed. Before and after ligation, glucose tolerance and intraductal pressure were measured, and pancreatic juice was collected after stimulation with cholecystokinin and secretin. Amylase and lipase activities were analyzed in plasma and juice. Pancreatic tissue was collected for histochemical analysis. Results: Within 4 weeks of ligation, the pancreas appeared atrophic. Intraductal pressure had risen significantly. Acinar-to-ductal metaplasia was accompanied by strong proliferation of stellate cells and increased collagen deposition. Islets of Langerhans appeared smaller and more numerous. Blood amylase and lipase levels were normal and glucose tolerance was unaffected. Pancreatic juice volume and amylase and lipase activities were significantly lower. Conclusion: Ligation of the PD in pigs resulted in a marked fibrosing obstructive pancreatitis within 4 weeks, similar to human chronic pancreatitis in regard to clinical, functional, histological and biochemical parameters.

Effect of in situ hypothermic perfusion on intrahepatic pO2 and reactive oxygen species formation after partial hepatectomy under total hepatic vascular exclusion in pigs

Abstract: Aim:  This study examined attenuation of ischemia and reperfusion (I/R) induced liver injury during liver resections by hypothermic perfusion of the liver under total hepatic vascular exclusion (THVE). Method: Reactive oxygen species (ROS) formation, microcirculatory integrity and endothelial cell damage were investigated. Left hemihepatectomy (LHX) was performed without in situ perfusion (control‐LHX, n = 5) or with concomitant in situ perfusion with hypothermic (4 °C) Ringer‐glucose (cold‐LHX, n = 5) or normothermic (38 °C) Ringer‐glucose (warm‐LHX, n = 5). Glutathione (GSH) and malondialdehyde (MDA) concentrations, tissue pO2 levels and hyaluronic acid (HA) uptake capacity were determined. Results: After cold, warm and control‐LHX, 24 h survival was 5/5, 0/5 and 3/5, respectively. GSH levels were best preserved after cold‐LHX during reperfusion. MDA levels increased in all groups without significant differences between the groups during reperfusion. Tissue pO2 levels increased after cold‐LHX whereas after warm‐LHX and control‐LHX, pO2 levels decreased during reperfusion. HA uptake capacity remained normal after cold‐LHX. After warm‐LHX and control‐LHX, HA uptake capacity decreased after 6 h of reperfusion but recovered after 24 h of reperfusion in the control‐LHX group. Conclusion: Moderate hypothermic perfusion protects the liver from I/R injury during LHX under THVE. This protective effect depended on maintenance of liver microcirculation rather than a reduction in ROS formation.