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Engraftment of human hepatocytes in the livers of rats bearing bone marrow reconstructed with immunodeficient mouse bone marrow cells
Author(s) -
Igarashi Yuka,
Tateno Chise,
Tanaka Yuka,
Tachibana Asato,
Utoh Rie,
Kataoka Miho,
Ohdan Hideki,
Asahara Toshimasa,
Yoshizato Katsutoshi
Publication year - 2008
Publication title -
xenotransplantation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.052
H-Index - 61
eISSN - 1399-3089
pISSN - 0908-665X
DOI - 10.1111/j.1399-3089.2008.00483.x
Subject(s) - bone marrow , hepatocyte , biology , severe combined immunodeficiency , microbiology and biotechnology , peripheral blood mononuclear cell , transplantation , flow cytometry , pathology , immunology , medicine , in vivo , in vitro , biochemistry
Background: Previously, we created, a chimeric mouse (humanized mouse), a severe combined immunodeficiency (SCID) mouse whose liver was >90% repopulated with human ( h )‐hepatocytes, which are useful for the testing of drug metabolism and toxicity, as well as a hepatitis B virus and hepatitis C virus‐susceptible animal model. However, their small body size and small total blood volume limited the utilization for analytical purposes, which led us to develop a method to create a chimeric rat bearing h ‐hepatocyte‐repopulated liver. Methods: F344 nude rats devoid of T cells were irradiated with X‐rays and injected with bone marrow cells (BMCs) from SCID mice ( m SCID ). The rate of replacement with m SCID ‐BMCs was evaluated by two‐color flow cytometry analysis of peripheral blood mononuclear cells (PBMCs). After m SCID ‐BMCs repopulated the host bone marrow (BM), the rats were treated with retrorsine, partially hepatectomized (PHx), and transplanted with 5 × 10 6 h ‐hepatocytes isolated from the chimeric mice. h ‐Albumin ( h ‐Alb) concentrations in the host blood and the expression levels of protein and mRNA of hepatocyte differentiation markers in the h ‐hepatocytes were evaluated by ELISA, immunostaining, and reverse transcription‐PCR, respectively. Results: The m SCID ‐BMCs successfully repopulated the rats, the percentage of mouse cells reaching 94% among host ( r nudeF344 ) PBMCs at 4 weeks after m‐ BMC transplantation. h ‐Hepatocytes isolated from the chimeric mice were transplanted to the liver of the m SCID ‐BMC‐repopulated rats. The engrafted h ‐hepatocytes expressed h ‐Alb and h ‐cytochrome P450 (CYP) subtypes and survived showing normal phenotypes until at least 3 weeks post‐ h ‐hepatocytes transplantation ( h ‐HPCT). However, the blood concentrations of h ‐Alb declined at 4 weeks post‐HPCT, concomitant with the emergence of both r nudeF344 ‐ and m SCID ‐macrophages, suggesting the rejection of h ‐hepatocytes due to the activation of macrophages. Conclusion: We developed a novel method to create a rat that bears the liver engrafted with h ‐hepatocytes, utilizing a rat with the BM composed of m SCID ‐BMCs as a host. This h ‐hepatocyte‐bearing rat will be a valuable model for studying the immunologic mechanisms involved in xenogeneic transplantation and for generating rats with higher rates of repopulation with h ‐hepatocytes.