6. Normothermic perfusion of porcine ex vivo livers to study hepatic pharmacokinetic processes

L.J. Stevens, J. Dubbeld, J.B. Doppenberg, B. van Hoek, C.A.J. Knibbe, W.H.J. Vaes, E. van de Steeg, I.P.J. Alwayn

Wednesday 4 march 2020

0:00 - 0:00h at Toon Hermans Foyer

Parallel session: Postersessie 2 – Basale abstracts

Background: Good prediction of human pharmacokinetics during preclinical drug development is hampered by the lack of translational in vitro and in vivo models, especially regarding prediction of hepatic clearance and biliary excretion. On top of this, an increasing number of newly developed drugs are subjective to enterohepatic circulation, enhancing the difficulty to predict plasma profiles after oral and intravenous administration, also since these drugs are more prone to cause a drug-drug interaction. We therefore aim to develop a preclinical model to investigate hepatic clearance, biliary excretion and DDI by utilizing normothermic machine perfusion (NMP) on porcine livers.

Methods: Porcine livers were procured from a slaughterhouse. Two livers underwent NMP using the LiverAssist machine. Blood gas analyses were performed hourly. A bolus of atorvastatin was administered at t=0 and at t=120 minutes a subsequent bolus of atorvastatin was co-administered with rifampicin. Samples from the perfusate and bile were taken at prespecified times and bilirubin as endogenous marker for OATP1B1/B3 function was measured. After 360 minutes, indocyanine green (ICG) was administered to study the liver functionality.

Results: Warm and cold ischemia times were 16±4 min and 142±23 min respectively. In both livers atorvastatin was rapidly cleared within 30 min from circulation after the first dose with a Cmax of 38.9 ± 3.54 ng/mL. Upon co-administration with rifampicin, the atorvastatin plasma levels increased showing a Cmax of 230.0 and 56.7 ng/mL and the area under the curve ratio (AUCR) was 6.8 and 1.7, respectively, indicating DDI. We hypothesize that the discrepancy in Cmax and AUCR can be attributed to measured differences in flow, resistance and genetic differences in transport and metabolism of the pigs. In both livers, upon administration of rifampicin, the biliary bilirubin concentration decreased while bilirubin in the circulation increased, suggesting inhibition of the OATP1B1/B3 transporters. At the end of the experiment, in both livers, ICG was rapidly cleared (t½ 6 min) from the circulation and excreted in the bile demonstrating good functionality and viability of the porcine liver after 6 h of NMP.

Conclusions: We have demonstrated the feasibility of applying NMP of porcine livers to study hepatic clearance, biliary excretion and DDI, and will further explore the potential of this model by studying other drugs and DDIs in comparison to clinical data.