Extrahepatic Bile Duct Organoids as a Model to Study Ischemia/Reperfusion Injury during Liver Transplantation

Introduction Biliary complications are still a major cause for morbidity and mortality after liver transplantation. Ischemia/reperfusions injury (IRI) leads to disruption of the biliary epithelium. Yet little is known about the underlying molecular mechanism. We introduce a novel model to study the effect of IRI on human cholangiocytes using extrahepatic cholangiocyte organoids (ECOs).

Method Extrahepatic bile duct tissue was collected during liver transplantation at static cold storage and after reperfusion (n=15). Gallbladder tissue was used as control (n=5). ECOs (n=9) were cultured from extrahepatic biliary tissue. Multiplex immunofluorescence, in-situ hybridization and qRT-PCR were performed to study programmed cell death. IRI was induced in ECOs by introducing cells to a hypoxic chamber for 48h, followed by reoxygenation.

Results After reperfusion an activation of programmed cell death was observed (p=0.002). Cultured ECOs formed circular structures recreating a tubular structure similar to that found in the bile duct. Analysis revealed a cholangiocyte phenotype of the ECOs. After hypoxia ECOs showed increased expression of ACSL4 (p<0.0001) and VEGF- A (p<0.0001). HIF1-α expression was increased after reoxygenation (p<0.0001). Expression patterns were similar to those found in the bile duct biopsies at static cold storage.

Discussion ECOs are in-vitro cellular systems that self-organize through mechanisms like those found in-vivo. They recapitulate the structure and exhibit similar patterns of ACSL4, VEGF- A and HIF1-α expression as extrahepatic bile duct during liver transplantation and thus provide a suitable model to study IRI in choanocytes after liver transplantation.

 

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Publication History

Article published online:
18 January 2023