Fate of hepatocyte and sinusoidal lining cell function and kinetics after extended cold preservation and transplantation of the rat liver

We investigated the chronological profile of graft damage and recovery after liver cold ischemia-reperfusion (I/R) injury, with particular attention to the role of apoptosis on hepatocyte and sinusoidal endothelial cell (SEC) damage. Male Lewis rats underwent rearterialized orthotopic liver transplantation using grafts subjected to a short (University of Wisconsin [UW] solution for 1 hour [UW1h]) and prolonged period (UW16h) of cold preservation. Experiments were performed immediately after preservation and 4 hours, 24 hours, 3 days, and 7 days after reperfusion. At each time, graft function, incidence of apoptotic cells, expression of the epitope recognized by a monoclonal antibody specific to rat SECs (SE-1), and incidence of proliferating cells were estimated. In the UW16h group, the proportion of apoptotic SECs was markedly elevated at 4 hours. The incidence of hepatocyte apoptosis was very low, although massive hepatocyte necrosis was evident at 24 hours. The incidence of proliferating hepatocytes and SECs peaked at 3 days, then returned to normal by 7 days. SE-1 expression was reduced immediately after preservation, followed by a marked reduction at 4 and 24 hours after reperfusion, and expression returned to normal by 7 days. Although SEC apoptosis was induced in the early phase of cold I/R injury, hepatocyte damage developed without the occurrence of apoptosis. Regeneration of both hepatocytes and SECs after cold I/R injury peaked at 3 days and was complete by 7 days, whereas functional recovery of these cell populations was complete 3 days after reperfusion.