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Therapeutic efficacy of human hepatocyte transplantation in a SCID/uPA mouse model with inducible liver disease.

Douglas DN, Kawahara T, Sis B, Bond D, Fischer KP, Tyrrell DL, Lewis JT, Kneteman NM - PLoS ONE (2010)

Bottom Line: In vitro experiments demonstrated efficient killing of vTK expressing hepatoma cells after GCV treatment.Surprisingly, vTK/GCV-dependent apoptosis and mitochondrial aberrations were also localized to bystander vTK-negative HH.Functional support by engrafted HH may be secured by strategies aimed at limiting this bystander effect.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery, University of Alberta, Edmonton, Alberta, Canada. donnad@ualberta.ca

ABSTRACT

Background: Severe Combined Immune Deficient (SCID)/Urokinase-type Plasminogen Activator (uPA) mice undergo liver failure and are useful hosts for the propagation of transplanted human hepatocytes (HH) which must compete with recipient-derived hepatocytes for replacement of the diseased liver parenchyma. While partial replacement by HH has proven useful for studies with Hepatitis C virus, complete replacement of SCID/uPA mouse liver by HH has never been achieved and limits the broader application of these mice for other areas of biomedical research. The herpes simplex virus type-1 thymidine kinase (HSVtk)/ganciclovir (GCV) system is a powerful tool for cell-specific ablation in transgenic animals. The aim of this study was to selectively eliminate murine-derived parenchymal liver cells from humanized SCID/uPA mouse liver in order to achieve mice with completely humanized liver parenchyma. Thus, we reproduced the HSVtk (vTK)/GCV system of hepatic failure in SCID/uPA mice.

Methodology/principal findings: In vitro experiments demonstrated efficient killing of vTK expressing hepatoma cells after GCV treatment. For in vivo experiments, expression of vTK was targeted to the livers of FVB/N and SCID/uPA mice. Hepatic sensitivity to GCV was first established in FVB/N mice since these mice do not undergo liver failure inherent to SCID/uPA mice. Hepatic vTK expression was found to be an integral component of GCV-induced pathologic and biochemical alterations and caused death due to liver dysfunction in vTK transgenic FVB/N and non-transplanted SCID/uPA mice. In SCID/uPA mice with humanized liver, vTK/GCV caused death despite extensive replacement of the mouse liver parenchyma with HH (ranging from 32-87%). Surprisingly, vTK/GCV-dependent apoptosis and mitochondrial aberrations were also localized to bystander vTK-negative HH.

Conclusions/significance: Extensive replacement of mouse liver parenchyma by HH does not provide a secure therapeutic advantage against vTK/GCV-induced cytotoxicity targeted to residual mouse hepatocytes. Functional support by engrafted HH may be secured by strategies aimed at limiting this bystander effect.

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Histopathological changes induced by vTK/GCV in chimeric SCID/uPA mice.Engrafted human hepatocytes (HH, bordered by dashed line) in paraffin embedded liver sections from experimental mice (Table 2) were identified by hybridization with fluoresceinated Alu probe (top). Serial sections were analyzed by H& E staining (bottom). MH; mouse hepatoctyes. Original magnification ×100.
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pone-0009209-g009: Histopathological changes induced by vTK/GCV in chimeric SCID/uPA mice.Engrafted human hepatocytes (HH, bordered by dashed line) in paraffin embedded liver sections from experimental mice (Table 2) were identified by hybridization with fluoresceinated Alu probe (top). Serial sections were analyzed by H& E staining (bottom). MH; mouse hepatoctyes. Original magnification ×100.

Mentions: Diffuse cytoplasmic and nuclear enlargement were readily detected in the MH populations of chimeric livers from vTK+ SCID/uPA mice that received GCV but had normal histology in chimeric livers from vTK− SCID/uPA (despite 100 mg/kg GCV dosing, Fig. 9). Increased apoptotic and acidophilic bodies were detected in both MH and HH populations of chimeric livers from vTK+ SCID/uPA that received GCV compared to those from mice that did not receive GCV and vTK− SCID/uPA mice (not shown). Serial Alu and TUNEL staining revealed TUNEL-positive apoptotic nuclei in both MH and HH populations of chimeric liver from vTK+ mice that received GCV (Fig. 10). By contrast, TUNEL-positive cells were rarely seen in chimeric livers from vTK+ SCID/uPA mice that did not receive GCV and vTK− chimeric mice (15% versus 1%, respectively, not shown).


Therapeutic efficacy of human hepatocyte transplantation in a SCID/uPA mouse model with inducible liver disease.

Douglas DN, Kawahara T, Sis B, Bond D, Fischer KP, Tyrrell DL, Lewis JT, Kneteman NM - PLoS ONE (2010)

Histopathological changes induced by vTK/GCV in chimeric SCID/uPA mice.Engrafted human hepatocytes (HH, bordered by dashed line) in paraffin embedded liver sections from experimental mice (Table 2) were identified by hybridization with fluoresceinated Alu probe (top). Serial sections were analyzed by H& E staining (bottom). MH; mouse hepatoctyes. Original magnification ×100.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2823785&req=5

pone-0009209-g009: Histopathological changes induced by vTK/GCV in chimeric SCID/uPA mice.Engrafted human hepatocytes (HH, bordered by dashed line) in paraffin embedded liver sections from experimental mice (Table 2) were identified by hybridization with fluoresceinated Alu probe (top). Serial sections were analyzed by H& E staining (bottom). MH; mouse hepatoctyes. Original magnification ×100.
Mentions: Diffuse cytoplasmic and nuclear enlargement were readily detected in the MH populations of chimeric livers from vTK+ SCID/uPA mice that received GCV but had normal histology in chimeric livers from vTK− SCID/uPA (despite 100 mg/kg GCV dosing, Fig. 9). Increased apoptotic and acidophilic bodies were detected in both MH and HH populations of chimeric livers from vTK+ SCID/uPA that received GCV compared to those from mice that did not receive GCV and vTK− SCID/uPA mice (not shown). Serial Alu and TUNEL staining revealed TUNEL-positive apoptotic nuclei in both MH and HH populations of chimeric liver from vTK+ mice that received GCV (Fig. 10). By contrast, TUNEL-positive cells were rarely seen in chimeric livers from vTK+ SCID/uPA mice that did not receive GCV and vTK− chimeric mice (15% versus 1%, respectively, not shown).

Bottom Line: In vitro experiments demonstrated efficient killing of vTK expressing hepatoma cells after GCV treatment.Surprisingly, vTK/GCV-dependent apoptosis and mitochondrial aberrations were also localized to bystander vTK-negative HH.Functional support by engrafted HH may be secured by strategies aimed at limiting this bystander effect.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery, University of Alberta, Edmonton, Alberta, Canada. donnad@ualberta.ca

ABSTRACT

Background: Severe Combined Immune Deficient (SCID)/Urokinase-type Plasminogen Activator (uPA) mice undergo liver failure and are useful hosts for the propagation of transplanted human hepatocytes (HH) which must compete with recipient-derived hepatocytes for replacement of the diseased liver parenchyma. While partial replacement by HH has proven useful for studies with Hepatitis C virus, complete replacement of SCID/uPA mouse liver by HH has never been achieved and limits the broader application of these mice for other areas of biomedical research. The herpes simplex virus type-1 thymidine kinase (HSVtk)/ganciclovir (GCV) system is a powerful tool for cell-specific ablation in transgenic animals. The aim of this study was to selectively eliminate murine-derived parenchymal liver cells from humanized SCID/uPA mouse liver in order to achieve mice with completely humanized liver parenchyma. Thus, we reproduced the HSVtk (vTK)/GCV system of hepatic failure in SCID/uPA mice.

Methodology/principal findings: In vitro experiments demonstrated efficient killing of vTK expressing hepatoma cells after GCV treatment. For in vivo experiments, expression of vTK was targeted to the livers of FVB/N and SCID/uPA mice. Hepatic sensitivity to GCV was first established in FVB/N mice since these mice do not undergo liver failure inherent to SCID/uPA mice. Hepatic vTK expression was found to be an integral component of GCV-induced pathologic and biochemical alterations and caused death due to liver dysfunction in vTK transgenic FVB/N and non-transplanted SCID/uPA mice. In SCID/uPA mice with humanized liver, vTK/GCV caused death despite extensive replacement of the mouse liver parenchyma with HH (ranging from 32-87%). Surprisingly, vTK/GCV-dependent apoptosis and mitochondrial aberrations were also localized to bystander vTK-negative HH.

Conclusions/significance: Extensive replacement of mouse liver parenchyma by HH does not provide a secure therapeutic advantage against vTK/GCV-induced cytotoxicity targeted to residual mouse hepatocytes. Functional support by engrafted HH may be secured by strategies aimed at limiting this bystander effect.

Show MeSH
Related in: MedlinePlus