A comparison of bile composition from heart-beating and non-heart-beating rabbit organ donors during normothermic extracorporeal liver perfusion: experimental evaluation using proton magnetic resonance spectroscopy.

Background: Organs retrieved from marginal and non-heart-beating donors (NHBDs) have sustained variable degrees of preretrieval damage that result in an increased incidence of complications. Normothermic extracorporeal liver perfusion (NELP) provides an opportunity to evaluate and resuscitate such organs. The aim of this study was to identify markers of ischemic injury in bile during perfusion of livers from heart-beating donors (HBDs) and NHBDs.

Methods: Livers were retrieved from New Zealand white rabbits. The HBD group (n=4) had no in situ warm ischemia before retrieval and the NHBD group (n=4), 45 minutes of in situ warm ischemia before liver retrieval. After 40 minutes of postretrieval cold ischemia, all livers were dual vessel reperfused, normothermically with oxygenated buffer solution supplemented with rabbit red blood cells, for 6 hours. Bile was collected and examined with 1HMRS.

Results: Perfusion bile from HBD group showed an increased concentration of bile acids, lactate, glucose, and phosphatidylcholine, but a decreased concentration of acetate as compared to retrieval bile. This trend was further enhanced in NHBD group. The mean +/- SD (in micromol/L) were bile acids (10.48 +/- 2.8 vs 26.05 +/- 12.1 vs 44.5 +/- 44.5), lactate (10.66 +/- 4.5 vs 14.66 +/- 5.2 vs 13.22 +/- 1.8), glucose (5.37 +/- 2 vs 21.2 +/- 5.0 vs 29.09 +/- 15.3), phosphatidylcholine (0.21 +/- 0.02 vs 5.57 +/- 1.7 vs 6.42 +/- 0.3), and acetate (1.8 +/- 0.5 vs 0.39 +/- 0.1 vs 0.38 +/- 0.09) for retrieval bile, HBD perfusion bile, and NHBD perfusion bile, respectively. One animal from each group did not produce any bile during perfusion.

Conclusions: 1HMRS of biliary constituents revealed differences with the type of ischemia. These indices may be potential markers of the extent of warm ischemic injury and the functional activity of an extracorporeally perfused liver.