Portal Hyperperfusion Causes Disturbance of Microcirculation and Increased Rate of Hepatocellular Apoptosis: Investigations in Heterotopic Rat Liver Transplantation With Portal Vein Arterialization

In group II, the average portal blood flow after reperfusion was significantly elevated (group II: 6.4 ± 1.5; group I: 1.7 ± 0.4 mL/min/g of liver weight; P < .001). The sinusoidal diameter after reperfusion was significantly greater in group II (9.8 ± 0.5 μm) than in group I (5.5 ± 0.2 μm; P < .001). Red blood cell velocity in the dilated sinusoids was significantly lower in group II (171 ± 18 μm/s) than in group I (252 ± 13 μm/s). Stasis of erythrocytes occurred; consequently, the functional sinusoidal density was significantly reduced in group II (38 ± 7%) compared with group I (50 ± 3%; P < .01). Two hours after reperfusion of the portal vein, the number of apoptotic hepatocytes was significantly higher in group II than in group I (I: 0 ± 0 vs II: 7 ± 9 M30-positive hepatocytes/10 high-power fields). The 6-week survival rate was 9 of 11 in both groups. In group II, 6 of 9 grafts showed massive hepatocellular necroses after 6 weeks, whereas in group I, only 1 of 9 presented a slight hepatocellular necrosis. Finally, our results demonstrate negative effects of portal hyperperfusion in transplanted livers, which are correctable by adequate flow regulation.