Acute and chronic liver failing is a highly prevalent medical condition with high morbidity and mortality. injury. This allows selective expansion of human hepatocytes upon transplantation. Human hepatocytes are typically injected at 1 month after birth. Given the young age of the animals, the transplantation procedure is stressful, and animals only tolerate cell doses of about 5 105C1 106 cells. Moreover, only homozygous uPA-SCID recipients allow for efficient and stable engraftment of exogenous 56390-09-1 hepatocytes, hence strongly reducing the number of experimentally available pups within one litter. Tateno at al. developed the so-called cDNA-uPA-SCID model, a mouse model expressing the cDNA of (instead of the whole gene), which allows repopulation of human hepatocytes in hemizygous animals [13]. In addition, uPA overexpressing mice can be backcrossed with immunodeficient mouse strains other than SCID mice, like [14,15] and [16]. A second mouse model, the fumaryl acetoacetate hydrolase ((FRG) mouse, is based on the genetic knockout of the gene. FAH is essential in the tyrosine catabolic pathway and absence of the protein results in the accumulation of fumaryl acetoacetate in the murine hepatocytes, leading to hepatic damage. This can be prevented by treating the mice with 2-(2-nitro- 4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC), which blocks the accumulation of fumaryl acetoacetate by inhibiting 4-hydroxyphenylpyruvate-dioxygenase. Withdrawal of NTBC typically results in demise of the animal within 4C8 weeks. Even after transplantation of healthy hepatocytes, 56390-09-1 animals should be provided with NTBC intermittently, before donor cells possess repopulated the liver organ to aid hepatic features [17 sufficiently,18]. As managed administration of NTBC will keep the pets alive and damage could be induced at at any time by withdrawal from the medication, older pets and, consequently, higher cell dosages (up till 5 106) could be used. Just like overexpressing mice, FRG mice could be backcrossed with pets of different immunological backgrounds, e.g., the nonobese diabetic (NOD) stress (FRGN Mouse monoclonal to Caveolin 1 mice) as 56390-09-1 well as the severe-combined immunodeficiency (SCID) stress (FRGS mice) [19,20,21]. Extra transgenic mouse versions have been created, which the thymidine kinase TK-NOG [22,23] as well as the AFC8 [24,25] mouse versions will be the most common. TK-NOG mice are immunodeficient mice that communicate herpes simplex type 1 thymidine kinase in hepatocytes pursuing ganciclovir administration, which in turn causes hepatotoxicity [22,23]. Nevertheless, repopulation in TK-NOG mice can be less effective than in uPA-SCID mice [22]. The AFC8 mouse consists of an FK506 binding protein-Caspase 8 fusion gene in order from the albumin promoter. When dimerizer ligand AP20187 can be given, the fusion proteins dimerizes, resulting in apoptosis from the hepatocytes [24,25]. The AFC8 model, produced by Washburn et al., in BALB/c mice, was the 1st humanized dual chimeric mouse model with both a humanized liver organ and immune system. However as for TK-NOG mice, repopulation of human hepatocytes in AFC8 mice has been reported to be less efficient than in uPA-SCID and FRG mice [24]. 2.1.4. Additional Methods to Improve Engraftment Efficiency Additional methods to improve liver repopulation potential in rodents have been investigated. This includes the use of additional immunosuppression, such as administration of the Natural Killer Cell inhibitor, anti-asialo-GM1, or an inhibitor of human complement activation, Futhan [13,26,27]. Mice have also been treated with JO2, a mouse CD95 antibody that increases apoptosis of mouse liver cells and enhances human hepatocyte engraftment. Alternatively, 56390-09-1 it might also be possible to enhance the engraftment efficiency of the grafted hepatocytes by treatment with, e.g., XMU-MP-1, an inhibitor of pro-apoptotic MST1/2, or the 5D5 antibody, an agonist of the c-Met receptor and therefore an inducer of hepatocyte.