TOLERANCE BY OLD LIVERS OF PROLONGED PERIODS OF PRESERVATION IN THE RAT

To determine the tolerance of old livers to prolonged preservation, livers from aged rats (corresponding to humans in the sixth to seventh decades of life) were transplanted after specific periods of cold preservation. Male BN/BiRij rats received orthotopic, arterialized liver grafts from either young (5 month) or old (25 to 28 month) donor rats after liver storage for 12 (n=6), 24 (n=6) or 30 (n=10) hours in University of Wisconsin solution. Outcome was assessed by survival, liver enzymes after transplantation, and histology of the grafts. There were no significant differences in survival rates between recipients of old and young grafts. All rats survived after 12-hr and 24-hr preservation except one recipient of an old graft preserved for 24 hr. After 30-hr preservation recipients of old and young livers had identical survival rates (60%). There was a strong correlation between the highest postoperative AST and ALT and the duration of preservation in all groups (P<0.0001), but only in the 24-hr preservation experiments was the ALT significantly higher in recipients of old grafts than in recipients of young livers (P=0.025). Age of the donor did not significantly affect the peak AST, but there was a correlation between donor age and the highest postoperative ALT (P=0.007). Although intracellular vacuolization was a prominent histological finding in more than half of the old livers at the end of preservation, it was not associated with an increase in mortality. It is concluded that under the ideal conditions provided in the experiments, old rat livers tolerate long preservation periods with satisfactory graft survival compared with young livers.