Biliary secretion of extracorporeal porcine: Livers with single and dual vessel perfusion

Background Hepatic support systems that provide detoxification without bili ary secretion (i.e., isolated hepatocyte systems) are sufficient to improve encephalopathy and bridge patients to transplantation. However, biliary se cretion may be critical when hepatic support attempts to restore function a nd regeneration of the host liver. The purpose of these studies was to opti mize the support liver secretory response to bile acid by either single-ves sel (portal vein; PV) or dual-vessel (hepatic artery [HA] + PV) perfusions during extracorporeal porcine liver perfusion. Methods. Extracorporeal porcine liver perfusion of anesthetized pigs was de veloped using support porcine livers perfused through the PV (n = 4) alone and through the HA + PV (n = 4) via a venovenous circuit. Support livers we re provoked with taurocholate (TC) to enhance bile aqueous and hydrophobic outputs. Results. After cold preservation and reperfusion, both PV and HA + PV liver s had initial 1-hr bile aqueous outputs < 15% of in vivo flow, with cholest erol (C) and phospholipid (PC) outputs <25% of in vive flow. Bile flow was significantly greater for recovered HA + PV livers (3.0 +/- 0.01 ml/15 min) than PV livers (1.9 +/- 0.01 ml/15 min). Despite this, PC output was signi ficantly greater for PV than HA + PV livers. The C/PC ratio of PV livers wa s twice that of HA + PV livers. TC infusion (48 mu mol/kg/15 min) of HA + P V livers demonstrated significantly greater increments in bile flow, PC out put, and C output than PV livers. Conclusion. In the unstimulated state, porcine support livers with dual-ves sel perfusion generated greater aqueous and C outputs despite diminished PC output than in those with single-vessel perfusion. TC stimulation increase d bile flow, PC output, and C output in dual-perfused livers more than in P V livers. HA + PV perfusion of support livers is the preferred technique fo r removing hydrophobic compounds that require PC transport for excretion or exist in the aqueous phase.