Recently, a rinse solution, Carolina rinse, designed to minimize reperfusion injury following liver transplantation in the rat has been developed. When used to rinse cold-stored grafts prior to completion of implantation surgery, Carolina rinse improved postoperative survival dramatically. Here we report the results of studies designed to determine the key components of Carolina rinse. Livers were explanted, stored for 12 hr in cold UW solution (0-4-degrees-C), and rinsed with 15 ml of Ringer's solution immediately prior to completion of implantation surgery. In this group, 12/13 rats died within 2 days (nonsurvival conditions). In a second group, explants stored under identical conditions were rinsed with 15 ml of Carolina rinse. Carolina rinse increased average 30-day survival time significantly to over 75%. Furthermore, when grafts were rinsed with Carolina rinse lacking nicardipine or with the pH increased to 7.4, long-term survival of recipient rats was also about 75% (i.e., the modifications did not affect survival). However, Carolina rinse lost its efficacy (12% survival) when adenosine was omitted. In addition, when donor livers were rinsed with Ringer's solution containing adenosine (0.1 mM), average survival time was increased from 8% to 63%. Rinsing with Ringer's solution containing higher concentrations of adenosine (5 mM), however, did not improve survival significantly. Survival was also not improved by rinsing with Ringer's containing 0.1 mM ribose and 0.1 mM adenine, substrates for ATP synthesis that are not vasoactive. SGOT values were around 3000 U/L 1-3 days postoperatively in the nonsurviving group rinsed with Ringer's solution alone. Values were decreased over 6-fold by Carolina rinse but were not reduced significantly by Ringer's solution containing adenosine. Thus, adenosine improves survival following liver transplantation without preventing parenchymal cell injury, indicating that adenosine may work via nonhepatic mechanisms. Liver injury was also assessed by electron microscopy. After either adenosine or Ringer's rinse, sinusoidal thrombi and polymorphonuclear margination were observed together with a pattern of pericentral hepatocellular vascuolization and disruption of the sinusoidal lining characteristic of changes observed following hypoxia. With Ringer's rinse, Kupffer cells exhibited surface irregularity in pericentral regions indicative of activation. Following adenosine rinse, however, Kupffer cells appeared more flattened with less ruffling and reduced surface debris (i.e., they were less activated). Carbon uptake by Kupffer cells was also decreased significantly by Ringer's rinse when adenosine was present. Furthermore, adenosine lowered intracellular free calcium concentration in cultured Kupffer cells and improved hepatic microcirculation postoperatively. Adenosine rinse also affected extrahepatic systems: it reduced postoperative clotting time and diminished lung injury significantly. Therefore, we designed Carolina rinse solution II that contains antioxidants to minimize liver injury and adenosine to improve survival. This new formulation was as effective as the original Carolina rinse at improving survival and minimizing graft injury.
