Preservation injury of the distal extrahepatic bile duct of donor livers is representative for injury of the intrahepatic bile ducts
Authors: Negin Karimian, Pepijn D. Weeder, Fernanda Bomfati, Annette S.H. Gouw, Robert J. Porte
Journal: Journal of Hepatology (2015)

We recently published an article in the Journal of Hepatology describing the histology of biopsies taken from the distal end of the extrahepatic bile duct of donor livers at the time of transplantation [[1]Op den Dries S. Westerkamp A.C. Karimian N. Gouw A.S. Bruinsma B.G. Markmann J.F. et al.Injury to peribiliary glands and vascular plexus before liver transplantation predicts formation of non-anastomotic biliary strictures.J Hepatol. 2014; 60: 1172-1179Abstract Full Text Full Text PDF PubMed Scopus (143) Google Scholar]. This study demonstrated the presence of severe biliary injury, characterized by loss of the lining biliary epithelium, mural stroma necrosis, as well as injury of the peribiliary glands (PBG) and peribiliary vasculature. Injury of deep PBG and peribiliary vasculature was identified as significant predictors of later development of non-anastomotic biliary strictures (NAS) after transplantation [[1]Op den Dries S. Westerkamp A.C. Karimian N. Gouw A.S. Bruinsma B.G. Markmann J.F. et al.Injury to peribiliary glands and vascular plexus before liver transplantation predicts formation of non-anastomotic biliary strictures.J Hepatol. 2014; 60: 1172-1179Abstract Full Text Full Text PDF PubMed Scopus (143) Google Scholar]. Severe injury and loss of the lining biliary epithelium is almost universally found in over 90% of donor extrahepatic bile duct biopsies taken at the time of transplantation [2Hansen T. Hollemann D. Pitton M.B. Heise M. Hoppe-Lotichius M. Schuchmann M. et al.Histological examination and evaluation of donor bile ducts received during orthotopic liver transplantation – A morphological clue to ischemic-type biliary lesion?.Virchows Arch. 2012; 461: 41-48Crossref PubMed Scopus (84) Google Scholar, 3Brunner S.M. Junger H. Ruemmele P. Schnitzbauer A.A. Doenecke A. Kirchner G.I. et al.Bile duct damage after cold storage of deceased donor livers predicts biliary complications after liver transplantation.J Hepatol. 2013; 58: 1133-1139Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar]. The observation that the degree of injury of PBG and vascular plexus correlates strongly with the development of NAS after transplantation suggests that insufficient regeneration of biliary epithelial lining after liver transplantation, due to destruction of the progenitor cell niche (i.e. the PBGs) and insufficient blood supply to bile ducts, is a critical component in the pathogenesis of NAS [1Op den Dries S. Westerkamp A.C. Karimian N. Gouw A.S. Bruinsma B.G. Markmann J.F. et al.Injury to peribiliary glands and vascular plexus before liver transplantation predicts formation of non-anastomotic biliary strictures.J Hepatol. 2014; 60: 1172-1179Abstract Full Text Full Text PDF PubMed Scopus (143) Google Scholar, 4Karimian N. Op den Dries S. Porte R.J. The origin of biliary strictures after liver transplantation: is it the amount of epithelial injury or insufficient regeneration that counts?.J Hepatol. 2013; 58: 1065-1067Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar]. In our previous study, as well as two other studies on bile duct histology of donor livers, biopsies could only be obtained from the distal end of the donor extrahepatic bile duct [2Hansen T. Hollemann D. Pitton M.B. Heise M. Hoppe-Lotichius M. Schuchmann M. et al.Histological examination and evaluation of donor bile ducts received during orthotopic liver transplantation – A morphological clue to ischemic-type biliary lesion?.Virchows Arch. 2012; 461: 41-48Crossref PubMed Scopus (84) Google Scholar, 3Brunner S.M. Junger H. Ruemmele P. Schnitzbauer A.A. Doenecke A. Kirchner G.I. et al.Bile duct damage after cold storage of deceased donor livers predicts biliary complications after liver transplantation.J Hepatol. 2013; 58: 1133-1139Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar]. It is, however, unknown whether the degree of injury at this level is representative for the degree of injury in the rest of the biliary tree, including intrahepatic bile ducts. To investigate whether histological injury detected in biopsies taken from the distal end of a donor liver bile duct is representative for the degree of injury of more proximal and intrahepatic large bile ducts, we have performed a study in nine donor livers that were declined for transplantation for various reasons (Table 1). Livers were collected after informed consent for research was obtained from donor relatives. All livers were procured in a standard fashion and preserved by cold flush out and storage in University of Wisconsin solution. After a median static cold storage time of 6.7 h biopsies were taken from the distal end of the extrahepatic bile duct as well as intrahepatic bile ducts at two different levels of sectoral ducts and segmental ducts (Fig. 1A). Injury of the bile ducts was assessed using a systematic histological scoring system as described previously [1Op den Dries S. Westerkamp A.C. Karimian N. Gouw A.S. Bruinsma B.G. Markmann J.F. et al.Injury to peribiliary glands and vascular plexus before liver transplantation predicts formation of non-anastomotic biliary strictures.J Hepatol. 2014; 60: 1172-1179Abstract Full Text Full Text PDF PubMed Scopus (143) Google Scholar, 2Hansen T. Hollemann D. Pitton M.B. Heise M. Hoppe-Lotichius M. Schuchmann M. et al.Histological examination and evaluation of donor bile ducts received during orthotopic liver transplantation – A morphological clue to ischemic-type biliary lesion?.Virchows Arch. 2012; 461: 41-48Crossref PubMed Scopus (84) Google Scholar] and were compared as matched pairs.Table 1Donor characteristics and surgical variables.∗Donor warm ischemia was defined from the moment of cardiac arrest after planned withdrawal of life support until cold flush out. DCD, donation after circulatory death; DBD, donation after brain death. Open table in a new tab ∗Donor warm ischemia was defined from the moment of cardiac arrest after planned withdrawal of life support until cold flush out. DCD, donation after circulatory death; DBD, donation after brain death. Biliary epithelial loss of >50% of the bile duct lumen was observed in all different levels of the biliary tree (Fig. 1B). The degree of mural stroma necrosis was not different among extrahepatic and intrahepatic bile ducts (Fig. 1B and C). There was minimal injury of peribiliary vascular plexus (<50% vascular changes) in 92.5% of all the biopsies and there was no significant difference among extrahepatic and intrahepatic bile ducts (Fig. 1D and E). No signs of microthrombi were found in the peribiliary vascular plexus and only minimal intramural bleeding (<50% of the bile duct) was observed in 5% of all biopsies. The degree of injury detected in periluminal PBG as well as in deep PBG was not significantly different among the various levels of the biliary tree (Fig. 1F–I). Severe injury (>50% epithelial loss) of the periluminal PBG was found in 40% of the livers, while severe injury of deep PBG was observed in only 6.6% (p <0.0001; χ2 test). This is the first study describing the degree of histological injury of donor liver bile ducts at different levels of the biliary tree, including larger intrahepatic bile ducts. In accordance with previous studies [2Hansen T. Hollemann D. Pitton M.B. Heise M. Hoppe-Lotichius M. Schuchmann M. et al.Histological examination and evaluation of donor bile ducts received during orthotopic liver transplantation – A morphological clue to ischemic-type biliary lesion?.Virchows Arch. 2012; 461: 41-48Crossref PubMed Scopus (84) Google Scholar, 3Brunner S.M. Junger H. Ruemmele P. Schnitzbauer A.A. Doenecke A. Kirchner G.I. et al.Bile duct damage after cold storage of deceased donor livers predicts biliary complications after liver transplantation.J Hepatol. 2013; 58: 1133-1139Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar], histological examination of bile ducts of donor livers after static cold preservation revealed signs of extensive injury. The current study adds important new information to the existing knowledge on biliary preservation injury obtained from studies describing the degree of injury in distal extrahepatic bile duct biopsies of donor livers [2Hansen T. Hollemann D. Pitton M.B. Heise M. Hoppe-Lotichius M. Schuchmann M. et al.Histological examination and evaluation of donor bile ducts received during orthotopic liver transplantation – A morphological clue to ischemic-type biliary lesion?.Virchows Arch. 2012; 461: 41-48Crossref PubMed Scopus (84) Google Scholar, 3Brunner S.M. Junger H. Ruemmele P. Schnitzbauer A.A. Doenecke A. Kirchner G.I. et al.Bile duct damage after cold storage of deceased donor livers predicts biliary complications after liver transplantation.J Hepatol. 2013; 58: 1133-1139Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar]. A limitation of this study is that the donor liver grafts used were declined for transplantation by centers within Eurotransplant regions. However, the type and degree of bile duct injury observed at the level of distal extrahepatic bile duct was similar to that described before in our previous study including 128 liver grafts that were used for transplantation [2Hansen T. Hollemann D. Pitton M.B. Heise M. Hoppe-Lotichius M. Schuchmann M. et al.Histological examination and evaluation of donor bile ducts received during orthotopic liver transplantation – A morphological clue to ischemic-type biliary lesion?.Virchows Arch. 2012; 461: 41-48Crossref PubMed Scopus (84) Google Scholar, 3Brunner S.M. Junger H. Ruemmele P. Schnitzbauer A.A. Doenecke A. Kirchner G.I. et al.Bile duct damage after cold storage of deceased donor livers predicts biliary complications after liver transplantation.J Hepatol. 2013; 58: 1133-1139Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar], as well as an experimental study using a porcine donation after circulatory death model [[5]Op den Dries S. Sutton M.E. Karimian N. de Boer M.T. Wiersema-Buist J. Gouw A.S. et al.Hypothermic oxygenated machine perfusion prevents arteriolonecrosis of the peribiliary plexus in pig livers donated after circulatory death.PLoS One. 2014; 9: e88521Crossref PubMed Scopus (95) Google Scholar]. Moreover, due to the nature of this study, which included collection of biopsies from larger intrahepatic bile ducts, there is no possibility to perform such a study in donor livers that are accepted for transplantation. Another limitation of this study is the small number of liver grafts used. Unfortunately, human livers are not available for research in large numbers. In conclusion, the degree of histological injury detected at distal end of extrahepatic bile duct of a donor liver is also representative for the degree of injury in the proximal parts of the biliary tree, including larger intrahepatic bile ducts. This study indicates that the biopsies taken from the distal end of the donor extrahepatic bile ducts are a valuable tool in research focusing on preservation injury of donor bile ducts during liver transplantation. The authors who have taken part in this letter to the editor declared that they do not have anything to disclose regarding funding or conflict of interest with respect to this manuscript. NK: Initiated the study, participated in the research design, performance of the research, data analysis and wrote the first draft of the paper. PDW: Participated in the performance of the research and writing of the paper. FB: Participated in the performance of the research and writing of the paper. ASHG: Participated in the performance of the research, histological analyses and writing of the paper. RJP: Initiated the study, participated in the research design, performance of the research, data analysis and writing of the paper. We are thankful to Prof. Ton Lisman and Dr. Sanna op den Dries for their scientific support. Furthermore, we are appreciative to Janneke Wiersema-Buist for her technical support in preparation of the samples.