THE EVALUATION OF THE ISOLATED-PERFUSED LIVER AS A MODEL FOR THE ASSESSMENT OF LIVER PRESERVATION

An ex vivo isolated perfused porcine liver model was tested to assess its suitability for rapid, reliable and relatively cheap testing of or gan preservation solutions for liver transplantation. The model consis ts of a machine driven recirculating system incorporating an organ cha mber, blood pump and membrane oxygenator, Autologous blood was used fo r perfusion for a period of 2 h at a temperature of 37-degrees-C. The model was tested with five groups of livers which had sustained varyin g degrees of injury ranging from minimally damaged to those known to b e incapable of sustaining life when used for liver transplantation. Th e groups of livers were: (i) controls; (ii) preserved in University of Wisconsin solution (UW) for 6 h; (iii) preserved in an albumin-based extracellular fluid (ALB) for 6 h; (iv) preserved in UW for 18 h; and (v) preserved in ALB for 18 h. Bile production was found to be a relia ble parameter of preservation damage. Changes in perfusate levels of a spartate aminotransferase, potassium, glucose and calcium also occurre d in relationship to preservation damage. In contrast, weight gain of the liver, sequestration of the white cells and platelets in the liver , urea production and oxygen consumption were unreliable predictors of liver damage. Histology of biopsy specimens revealed apparently well preserved livers in all cases after preservation but before perfusion, but serious abnormalities after perfusion in long preserved livers, w ith features in these suggestive of damage to the sinusoidal endotheli um. We believe that the model is a worthwhile adjunct to research into liver preservation.