Repopulation of intrahepatic bile ducts in engineered rat liver grafts

Abstract

Engineered liver grafts for transplantation with sufficient hepatic function have been developed both in small and large animal models using the whole liver engineering approach. However, repopulation of the bile ducts in the whole liver scaffolds has not been addressed yet. In this study, we show the feasibility of repopulating the bile ducts in decellularized rat livers. Biliary epithelial cells were introduced into the bile ducts of the decellularized liver scaffolds with or without hepatocytes in the parenchymal space. The recellularized grafts were cultured under perfusion for up to 2 days and histological analysis revealed that the biliary epithelial cells formed duct-like structures, with the viable hepatocyte mass residing in the parenchymal space, in an arrangement highly comparable to the native tissue. The grafts were viable and functional as confirmed by both albumin and urea assay results and the gene expression analysis of biliary epithelial cells in recellularized liver grafts. This study provides the proof-of-concept results for rat liver grafts co-populated with parenchymal and biliary epithelial cells.

Development of liver microtissues with functional biliary ductular network

“…Another approach is hepatocyte transplantation, which is restricted by the low liver-engraftment rate and low survival rate of the transplanted hepatocytes (Ibars et al, 2016 with healthy liver cells such as primary or stem-cell-derived hepatocytes and nonparenchymal cells, especially with endothelial cells (Acun et al, 2019;Wang et al, 2017). The repopulation of the IHBDs, which is a critical component of the nonparenchymal population, has not been addressed in the engineered liver grafts until recently (Chen et al, 2019). The integration of BC to the bile ducts within engineered liver tissues is yet to be shown.…”

“…The repopulation of the intrahepatic bile ducts (IHBDs), which is a critical component of the nonparenchymal population, has been largely neglected in the engineered liver grafts until recently (Chen, Devalliere, Bulutoglu, Yarmush, & Uygun, 2019). IHBD constitute the biliary network formed by the cholangiocytes, or bile duct epithelial cells, whose primary role is to modify and transport the bile formed by the hepatocytes.…”

Liver regeneration biology: Implications for liver tumour therapies

“…In the last 10 years, a variety of animal models, decellularisation techniques, repopulation routes and cell sources have been described, with promising outcomes in terms of vascular repopulation[ 118 , 129 , 130 ], hepatocyte survival[ 131 ] as well as formation of biliary duct-like structures and activation of liver detoxification enzymes[ 132 ]. One of the commonest sources of liver scaffolds is the rat[ 118 , 127 , 132 - 137 ] repopulated with rat hepatocytes (although cholangiocytes[ 136 ] and lineages from pluripotent stem cells, mesenchymal cells, and fibroblasts have also been described[ 137 ] usually via the portal vein. With regards to human tissue, Verstegen et al [ 138 ] demonstrated that decellularised human livers can be repopulated with human umbilical vein endothelial cells, leading to re-endothelialisation of the vascular tree.…”

Role of Biliary Organoids in Cholestasis Research and Regenerative Medicine

“…The use of bile duct cells was demonstrated using rat liver scaffolds first repopulated with cholangiocytes through the extrahepatic biliary tree and then with hepatocytes via portal vein perfusion. 36 3D bioprinting can also be used to recreate the spatial relationship between different cell types, thus mimicking the native tissue microarchitecture. In this technology, a 3D printer layers biomatrix, such as hydrogel, and cells upon each other to create the desired structure.…”