The significance of tissue-type plasminogen activator for pretransplant assessment of liver graft viability: analysis of effluent from the graft in rats

Abstract

We studied the significance of tissue-type plasminogen activator (tPA) on the pretransplant assessment of liver graft viability in rats. The liver grafts were excised from the rats and then divided into two groups. Group 1 consisted of grafts preserved for 4 h in chilled, lactated Ringer's solution (4 degrees C) and group 2 consisted of grafts preserved for 6 h in the same solution. After preservation, the liver grafts were flushed out through the portal vein using 5 ml of chilled, lactated Ringer's solution (4 degrees C). The entire effluent from the hepatic veins was then collected and analyzed for tPA, ammonia, lactate, pyruvate, glutamic oxaloacetic transaminase, and lactate dehydrogenase. The tPA concentration of effluent in group 2 was significantly higher than that in group 1 (0.80 +/- 0.23 ng/ml vs 0.42 +/- 0.08 ng/ml, P < 0.05). The lactate, pyruvate, and ammonia levels in group 2 were also higher than those in group 1 (134 +/- 13 mg/dl vs 120 +/- 2 mg/dl, 0.34 +/- 0.40 mg/dl vs 0.09 +/- 0.01 mg/dl, and 183 +/- 79 micrograms/dl vs 102 +/- 40 micrograms/dl, respectively). However, the discriminative power of tPA was stronger than that of the other parameters. Histological findings revealed a higher number of trypan blue-stained sinusoidal lining cells that were detached and swollen in group 2. We conclude that the amount of tPA in the effluent flushed from the graft can serve as a sensitive and reliable indicator of cold-preserved liver grafts in rats.