24 Hours of Hypothermic Machine Perfusion of Rat Livers. Effects on Bile Composition

CARNEVALE M.E.; MÉJICO G.; BALABAN C.L.; GUIBERT E.E.; RODRIGUEZ J.V.

Viña del Mar

Workshop; 3° Workshop de Biomateriais, Engenharia de Tecidos e Orgãos Artificiais (4°OBI); 2013

Sociedad Latinoamericana de Órganos Artificiales, Biomateriales e Ingeniería de Tejidos

The continuous hypothermic perfusion system to preserve livers prior to transplantation represents an alternative strategy for the rescuing of marginal liver donors and it is barely used in clinic transplantation. The ideal hypothermic perfusion setting to apply in livers has not yet been really defined, but one key question that has remained is the effect of composition solution on the maintenance of liver viability and function during normothermic reperfusion. The present study was undertaken to analyse bile flow and bile composition after 24 h rat liver hypothermic perfusion machine (HMP), using a new solution (BGP-HMP) for HMP of livers for transplant. The portal vein and bile duct of Wistar rats were cannulated, the liver excised, washed and connected on a recirculating perfusion system with 250 mL of BES-Gluconate-Polyethylene Glycol based solution (BGP-HMP) at 5C and a flow rate of 5mL/min (Carnevale M, Cryobiology 65:357, 2013) up to 24 h at a constant pressure of 40 mmH2O (equivalent to 25 % of the normothermic portal pressure). Reperfusion at 37°C was accomplished in an ex vivo system (IPRL) with Krebs-Henseleit Dextran solution (Balaban CL, Artif Organs 35(5):508-15, 2011). Liver functionality, tissue injury and bile composition were evaluated during the HMP and reperfusion in 2 experimental groups: I- Fresh harvested livers reperfused 90 min in IPRL; II- 24 h HMP of livers + reperfusion in IPRL. In both procedures, portal pressure and flow rate were measured and the intrahepatic resistance (IR) was calculated. Perfusate pH oscillations and enzyme (LDH) activity were evaluated during HMP and normothermic reperfusion. Also, the O2 consumption and bile flow were measured. Bile samples were collected in pre-weighed tubes during 90 min of reperfusion. Bile flow and bile excretion rate (BER) of electrolytes (Na+, K+, Cl-), cholesterol (CHO), phospholipids (Pi) and taurocholic acid (TC) were evaluated. Also the phospholipid bile composition was analyzed by thin layer chromatography. Liver function and viability during normothermic reperfusion: The portal flow and IR did not show differences between groups. The LDH released after 90 min of reperfusion showed statistical differences between both groups, HMP solution showed higher values than group I. With regard to O2 consumption, the livers that suffered HMP were able to uptake more O2 than livers from group I. HMP treatment produces a diminished bile flow respect to group I (I: 1.170.09, n=5; II: 0.42 ± 0.25 L/min/g.liver, p