Development of the Isolated Dual Perfused Rat Liver Model as an Improved Reperfusion Model for Transplantation Research

Abstract

The Isolated Perfused Liver (IPL) model is a widely used and appreciated in vitro method to demonstrate liver viability and metabolism. Reperfusion is performed in a controlled setting, however, via the portal vein only. To study transplant related questions concerning bile and transport of bile, the in vitro Isolated dual Perfused Liver model is revisited. The IdPL is an in vitro reperfusion model, using both portal vein and hepatic artery. Livers from 12 Wistar rats were flushed with University of Wisconsin-organ preservation solution, procured and reperfused in either the conventional IPL-model (n=6) or the new IdPL-model (n=6). Liver injury, assessed by the release of aspartate amino transferase and lactate dehydrogenase, showed similar levels during both IPL and IdPL reperfusion, only alanine amino transferase showed an improvement. Cumulative bile production showed an improvement: 176.3 ± 8.4 in the IdPL compared to 126.1 ± 12.2 μg/g-liver in the IPL (p<0.05). Clearance of phenol red (PR) and taurocholic acid (TC) remained similar. At 90 minutes reperfusion the PR clearance showed 0.11 ± 0.01 and 0.11 ± 0.02 mg/30min/g-liver and the TC clearance 1.01 ± 0.10 and 1.01 ± 0.07 μmol/ml/30min/g-liver in the IPL and IdPL, respectively. Increasing the reperfusion time beyond the normally used 90 minutes resulted in a significant increase in transaminases and LDH and a decrease in bile production, liver morphology remained intact and glycogen content was appropriate. In conclusion, the IdPL-model showed similar or better results than the IPL-model, but the liver could not endure an extended reperfusion time using the IdPL.