Transplanting human primary fetal liver cells and human hepatic stem cells into Alb-TRECK/SCID mice with fulminant hepatic failure. (A) Experimental protocols. Forty-eight hours after the intraperitoneal injection of diphtheria toxin (DT), mouse serum was collected for the aspartate aminotransferase (AST) assay, and mice livers (n = 5) were sampled for histological analyses. The human donor cells were then transplanted into mice livers (n = 54/group) on the same day. A human albumin enzyme-linked immunosorbent assay was performed after 50 days of transplantation (n = 6/group). On day 60 after transplantation, drug metabolism was examined in mice (n = 4 or more/group), and over 20 mice per group were used for the survival tracing. Mice that survived for more than 120 days were sacrificed for liver tissue sampling. (B) Kaplan–Meier survival curves of Alb-TRECK/SCID after transplantation with human primary fetal liver cells (FLCs) and human hepatic stem cells (HpSCs). (Numbers of transplanted mice in each group are indicated in the figure.) *P < 0.05, **P < 0.01. (C) Macroscopic views (left panels) and histology (hematoxylin and eosin (H&E) staining, right two panels) of humanized livers with human primary FLCs (upper panel) and human HpSCs (lower panel) at 6 weeks after transplantation. CV, central vein; PV, portal vein; m, mouse liver region; h, human donor cell-derived human region. Scale bars = 100 μm.