Evaluation of a new solution for hypothermic machine perfusion (HMP) of the liver. A study in the perfused rat liver in vitro

MATÍAS E. CARNEVALE; CECILIA L. BALABAN; EDGARDO E. GUIBERT; HEBE BOTTAI; JOAQUIN V. RODRIGUEZ

CRYOBIOLOGY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2012 vol. 65 p. 357 - 357

0011-2240

The present study was undertaken to develop and investigate the possible benefit of a new solution for hypothermic machine perfusion (HMP) of livers for transplants. The portal vein and bile duct of Wistar rats were cannulated, the liver excised and connected on a recirculating perfusion system with 250 mL of BES-Gluconate-Polyethylene Glycol based solution (BGP-HMP) or with Bretschneider solution (HTK) at 5 °C. HMP was performed up to 24 h at a constant pressure of 40 mmH2O (equivalent to 25% of the normothermic portal pressure). Both perfusion solutions were air equilibrated during the HMP. After 24 h of HMP, the livers were reperfused at 37 °C with Krebs?Henseleit Dextran solution (Balaban, C.L., 2011. Artif Organs 35(5), 508?515). In both procedures, portal pressure and flow rate were measured and the intrahepatic resistance (IR) was calculated. Perfusate pH oscillations and enzymes (LDH, AST, and ALT) activities were evaluated during HMP and normothermic reperfusion. Also, the O2 consumption, glucose, urea production and bile flow were measured during the normothermic reperfusion period.Liver perfusion variables and injury parameters during HMPStatistical differences in enzymes release (p < 0.05) were found between both groups (n = 5) during HMP. Enzyme activities in perfusate was (U/L.gliver): LDH, 10.01 ± 1.22 (HTK), 6.20 ± 1.03 (BGP?HMP); AST, 3.63 ± 0.62 (HTK), 1.25 ± 0.13 (BGP?HMP). In contrast, for ALT release no statistical differences were found.Liver function and viability during normothermic reperfusionThe portal flow was 1.63 ± 0.41 vs. 2.85 ± 0.59 (mL/min.gliver) with HTK and BGP?HMP respectively. The IR and enzyme release after 90 min of reperfusion showed statistical differences between both groups. HTK solution showed higher values than BGP?HMP: IR (mmHg.min.gliver/mL) 4.96 ± 1.15 vs. 2.79 ± 0.66; LDH 43.04 ± 13.2 vs. 15.1 ± 5.43; AST 8.5 ± 2.7 vs. 3.46 ± 1.02; ALT 3.72 ± 1 vs. 1.04 ± 0.5. These results indicate that BGP?HMP is able to maintain better membrane integrity of the hepatocytes and reduce the hypothermic preservation and reperfusion injuries of the livers. Also, hematoxylin/eosin stain analysis showed better integrity in livers treated with BGP?HMP than livers perfused with HTK solution. With regard to bile flow and O2 consumption, preserved livers with either solutions were able to produce bile, but the livers stored with BGP?HMP were able to uptake more O2 (μmol/min.gliver) than livers preserved with HTK: 1.08 ± 0.08 vs. 0.65 ± 0.1. So, in the setted conditions, the livers are able to keep an active metabolism with both preservation solutions, but the BGP?HMP solution enhances the graft O2 consumption capacity and reduces IR.