Assembly and Function of a Bioengineered Human Liver for Transplantation Generated Solely from Induced Pluripotent Stem Cells

Abstract

The availability of an autologous transplantable auxiliary liver would dramatically affect the treatment of liver disease. Assembly and function in vivo of a bioengineered human liver derived from induced pluripotent stem cells (iPSCs) has not been previously described. By improving methods for liver decellularization, recellularization, and differentiation of different liver cellular lineages of human iPSCs in an organ-like environment, we generated functional engineered human mini livers and performed transplantation in a rat model. Whereas previous studies recellularized liver scaffolds largely with rodent hepatocytes, we repopulated not only the parenchyma with human iPSC-hepatocytes but also the vascular system with human iPS-endothelial cells, and the bile duct network with human iPSC-biliary epithelial cells. The regenerated human iPSC-derived mini liver containing multiple cell types was tested in vivo and remained functional for 4 days after auxiliary liver transplantation in immunocompromised, engineered (IL2rg À/À ) rats.

Insulin/Glucose-Responsive Cells Derived from Induced Pluripotent Stem Cells: Disease Modeling and Treatment of Diabetes

“…Pancreatic progenitor cells express a group of transcription factors, of which PDX1 and NKX6.1 are critical markers for β-cell maturation and functionality (for more detail see [ 69 , 70 ]). PDX1 + /NKX6.1 + progenitors differentiate into monohormonal β-cells, while PDX1 + /NKX6.1 − progenitors differentiate into polyhormonal cells [ 71 , 72 ]. The differentiation efficiency of iPSCs to PDX1 + /NKX6.1 + progenitors is high under optimized conditions [ 70 , 71 , 73 ]; the PDX1 + /NKX6.1 − population is further increased when duration of the posterior foregut stage is prolonged [ 71 ].…”

“…At this stage, differentiated hepatoblasts display expression of FOXA1, FOXA2, CCAAT enhancer-binding protein alpha (CEBPα), peroxisome proliferator-activated receptor alpha (PPARα), alpha-fetoprotein (AFP), and cytokeratin (KRT)-18 and -19 [ 72 , 140 , 141 , 142 , 143 ]. After treatment with HGF, cells begin to express the adult isoforms of HNF1α and HNF4α, liver X receptor (LXR), ATP-binding cassette transporter A1 (ABCA1), alpha-1-antitrypsin (A1AT), albumin, as well as liver-specific microRNAs miR122, miR148a, and miR194 [ 72 ]. In addition, expression of retinoid X receptor (RXR) and vascular endothelial growth factor receptor (VEGFR) is increased and then declines progressively towards the final stages of differentiation [ 72 ].…”

“…After treatment with HGF, cells begin to express the adult isoforms of HNF1α and HNF4α, liver X receptor (LXR), ATP-binding cassette transporter A1 (ABCA1), alpha-1-antitrypsin (A1AT), albumin, as well as liver-specific microRNAs miR122, miR148a, and miR194 [ 72 ]. In addition, expression of retinoid X receptor (RXR) and vascular endothelial growth factor receptor (VEGFR) is increased and then declines progressively towards the final stages of differentiation [ 72 ].…”

“…Oncostatin M which belongs to interleukin (IL)-6 group of cytokines is produced by hematopoietic cells. In addition, various chemical compounds and small molecules such as dimethylsulfoxide (DMSO), dexamethasone, hydrocortisone-21- hemisuccinate and Ile-(6) aminohexanoic amide (dihexa) are used for iPSC differentiation from definitive endoderm to mature hepatocytes [ 72 , 140 , 141 , 143 ]. These molecules regulate specific target(s) in signaling and epigenetic mechanisms, as well as manipulate cell fate without genetic alterations.…”

Bioengineered Mini Human Livers for Transplantation

“…Incorporating liver decellularization/recellularization technology and harnessing the ability to differentiate iPSC into multiple liver cell lineages, Takeishi et al ( 4 ) recently generated functional bioengineered human livers. These mini livers, when transplanted into immunocompromised rats, maintained functionality for 4 days.…”