An in vitro method for comparing the efficacy of two preservation solutions in one canine liver using the 5‘-nucleotidase assay

Abstract

Abstract. The activity and localization of the plasma membrane-bound enzyme 5‘-nucleotidase (5’-NT) in liver tissue are sensitive parameters of ischemic damage. The value of 5‘-NT as a marker of liver graft viability was studied in relation to liver preservation. In six mongrel dogs, the main right and left branches of the portal vein were cannulated and flushed separately in situ with cold University of Wisconsin (UW) solution and Euro-Collins (EC) solution, respectively. After hepatectomy, the right and left liver lobes were split and stored at 5oC in either of the two solutions. 5’-NT activity was demonstrated in cryostat sections of liver tissue using the lead salt method. After 48 h of storage in EC solution, the 5‘-NT score had decreased to 31 ± 16 % (n = 6), whereas in UW solution the 5’-NT score was 76%± 10% (n=6). Significantly (P < 0·05) higher 5‘-NT scores were also found after 24-h and 72-h preservation times in UW versus EC solutions. This result is in keeping with the higher preservation tolerance of liver grafts preserved in UW solution. The 5’-NT assay was studied in relation to graft function in orthotopic liver transplantation experiments in dogs. All dogs with liver grafts preserved in UW solution for 24 h (n= 4) and 48 h (n= 3) survived (> 5 days). Pretransplant 5‘-NT scores ranged from 61% to 100%. The 72-h-preserved livers (n= 5) did not show life-supporting function. Pretransplant 5’-NT scores (33%± 12%, n = 5) were significantly (P < 0·05) decreased. The 5‘-NT score pretransplantation was a more reliable indicator of graft function than peak SGOT values post-transplantation. In conclusion, the 5’-NT assay, in conjunction with the double flush method through the portal vein, provides a simple and rapid “in vitro” method to test solutions for liver preservation.