Quality assessment by bile composition in normothermic machine perfusion of rat livers

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Item Type:	Article
Title:	Quality assessment by bile composition in normothermic machine perfusion of rat livers
Creators Name:	Muth, V., Strobl, F., Michelotto, J., Gilles, L., Kirwan, J., Eisenberger, A., Marchand, J., Roschke, N., Moosburner, S., Pratschke, J., Sauer, I.M., Raschzok, N. and Gassner, J.M.G.V.
Abstract:	BACKGROUND: The persistent challenge of organ scarcity in liver transplantation leads to an escalating dependence on organs obtained from extended criteria donors (ECD). Normothermic machine perfusion (NMP) is used for improved preservation. Due to the mimicked in vivo conditions during normothermic machine perfusion, the liver is metabolic active, which allows quality assessment during perfusion. Bile seems to be of rising interest in clinical studies since it is easily collectible for analysis. As there is currently no data on biliary bile acids during NMP, the primary objective of this study was to use our experimental rodent NMP model to assess changes in bile composition through organ damage during perfusion to inform clinical evaluation of donor organs during NMP. METHODS: 30 livers from male Sprague Dawley rats in five groups and underwent 6 hours of NMP using either erythrocyte-supplemented DMEM or Steen solution, with or without 30min of warm ischemia time (WIT). We conducted regular measurements of AST, ALT, LDH, and urea levels in the perfusate at three-hour intervals. Bile samples were analyzed for biliary pH, LDH and GGT as well as biliary bile acids via mass spectrometry and UHPLC. RESULTS: Compared to regular livers, liver injury parameters were significantly higher in our donation after circulatory death (DCD) model. Bile production was significantly reduced in livers exposed to WIT, and the bile showed a significantly more alkaline pH. This correlated with the concentration of total bile acids, which was significantly higher in livers experiencing WIT. However, regular livers produced a higher total amount of biliary bile acids during perfusion. Taurocholic acid and its metabolites were most prominent. Secondary bile acids were significantly reduced during perfusion due to the missing enterohepatic circulation. CONCLUSIONS: WIT-induced liver injury affects bile composition within our small animal NMP model. We hypothesize this phenomenon to be attributed to the energy-driven nature of bile secretion, potentially explaining why DCD livers produce less, yet more concentrated, bile. Our results may inform clinical studies, in which biliary bile acids might have a potential as a quantifiable viability marker in human NMP liver transplantation studies.
Source:	Tissue Engineering Part A
ISSN:	1937-335X
Publisher:	Mary Ann Liebert
Date:	4 June 2024
Official Publication:	https://doi.org/10.1089/ten.tea.2024.0048
PubMed:	View item in PubMed

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