Biomedical subjects

Naoya Kobayashi

Publications and source records attributed to Naoya Kobayashi.

At least 37 records · Page 2Linked to original sources

PubMed2005

Fasudil hydrochloride hydrate, a Rho-kinase (ROCK) inhibitor, suppresses collagen production and enhances collagenase activity in hepatic stellate cells.

BACKGROUND/AIMS: The Rho-ROCK signaling pathways play an important role in the activation of hepatic stellate cells (HSCs). We investigated the effects of fasudil hydrochloride hydrate (fasudil), a Rho-kinase (ROCK) inhibitor, on cell growth, collagen production, and collagenase activity in HSCs. METHODS: Rat HSCs and human HSC-derived TWNT-4 cells were cultured for studies on stress fiber formation and alpha-smooth muscle actin (alpha-SMA) expression. Proliferation was measured by BrdU incorporation, and apoptosis by TUNEL assay. The phosphorylation states of the MAP kinases (MAPKs), extra cellular signal -regulated kinase 1/2 (ERK1/2), c-jun kinase (JNK), and p38 were evaluated by western blot analysis. Type I collagen, matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) production and gene expression were evaluated by ELISA and real-time PCR, respectively. Collagenase activity (active MMP-1) was also evaluated. RESULTS: Fasudil (100 microM) inhibited cell spreading, the formation of stress fibers, and expression of alpha-SMA with concomitant suppression of cell growth, although it did not induce apoptosis. Fasudil inhibited phosphorylation of ERK1/2, JNK, and p38. Treatment with fasudil suppressed the production and transcription of collagen and TIMP, stimulated the production and transcription of MMP-1, and enhanced collagenase activity. CONCLUSION: These findings demonstrated that fasudil not only suppresses proliferation and collagen production but also increases collagenase activity.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed2005

Epigallocatechin-3-gallate, a polyphenol component of green tea, suppresses both collagen production and collagenase activity in hepatic stellate cells.

Catechins such as epigallocatechin-3-gallate (EGCG), epicatechin-3-gallate (ECG), and epigallocatechin (EGC) are polyphenol components of green tea. EGCG is the major component and has been reported to possess a wide range of biological properties including anti-fibrogenic activity. In hepatic fibrosis, activated hepatic stellate cells (HSCs) play a central role. In this study, we investigated the effect of catechins, including EGCG, on collagen production and collagenase activity in rat primary HSCs and activated human HSC-derived TWNT-4 cells. EGCG (50 microM) suppressed type I collagen production in rat HSCs more than ECG (50 microM) did; however, EGC (50 microM) did not show suppressive effects. EGCG also inhibited both collagen production and collagenase activity (active matrix metalloproteinase-1 [MMP-1]) in a dose-dependent manner, but did not affect the tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) production in TWNT-4 cells. Real-time PCR unexpectedly revealed that EGCG enhanced the transcription of type I collagen and TIMP-1, but did not affect the transcription of alpha-smooth muscle actin (alpha-SMA), and reduced the transcription MMP-1 in TWNT-4 cells. These findings demonstrated that EGCG inhibited collagen production regardless of enhanced collagen transcription and suppressed collagenase activity, and suggested that EGCG might have therapeutic potential for liver fibrosis.

Actins↗

PubMed2004

Establishment of an immortalized human-liver endothelial cell line with SV40T and hTERT.

BACKGROUND AND AIMS: Liver endothelial cells (LECs) perform an essential role in important pathophysiologic functions in the liver. Establishment of a human LEC line facilitates advances in LEC research. Here, we present immortalization of human LECs using retroviral gene transfer of simian virus 40 large T antigen (SV40T) and human telomerase reverse transcriptase (hTERT). We also demonstrate excision of SV40T and hTERT with TAT-mediated Cre/loxP recombination and subsequent cell sorting. METHODS: First, human LECs were transduced with a retroviral vector somatostatin receptor (SSR)#69 expressing SV40T and hygromycin-resistance genes flanked by a pair of loxA recombination targets. Then, cells were retrovirally superinfected with SSR#197 encoding hTERT and green fluorescent protein (GFP) cDNAs that were intervened by two loxBs. One SV40T-and hTERT-immortalized LEC clone, TMNK-1, was established and analyzed for its biologic characteristics. RESULTS: The cells were hygromycin-resistant and uniformly positive for GFP expression. TMNK-1 expressed EC markers, including factor VIII, vascular endothelial growth factor receptors (flt-1, KDR/Flk-1), and CD34, showed uptake of Di-I-acetylated-low-density lipoprotein and angiogenic potential in Matrigel assays. After lipopolysaccharide treatment, TMNK-1 produced tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 and exhibited increased expression of intra-cellular adhesive molecule-1, vascular cellular adhesive molecule-1, and VE-cadherin. After treatment with TAT-Cre recombinase fusion protein, approximately 60% of TMNK-1 was negative for GFP expression, and subsequent cell sorting of this population for GFP allowed for collection of the reverted form of TMNK-1. CONCLUSIONS: This study demonstrates the utility and efficiency of the reversible immortalization procedure to expand primary human LECs for basic studies.

Animals↗

PubMed2004

Establishment of a highly differentiated immortalized human cholangiocyte cell line with SV40T and hTERT.

BACKGROUND: Cholangiocytes perform an essential role in important pathophysiologic functions in the liver. Establishment of a human cholangiocyte line facilitates advances in cholangiocyte research and clinical applications for cell therapies. Here, we describe the immortalization of human cholangiocytes using serial transfection of simian virus 40 large T (SV40T) followed by human telomerase reverse transcriptase (hTERT). METHODS: SV40T-transduced human liver OUMS-21 cells were superinfected with a retroviral vector SSR#197 encoding hTERT and green fluorescent protein (GFP) cDNAs. Resulting cell lines were evaluated for gene expression, functional cholangiogenic characteristics in vitro and in vivo, and response to lipopolysaccharide (LPS). RESULTS: One of the SV40T- and hTERT-immortalized cholangiocyte clones, MMNK-1, was established. MMNK-1 expressed cholangiocyte markers, including cytokeratin (CK)-7 and -19 and exhibited cholangiogenic tubule formation in a Matrigel assay. When transplanted into the immunodeficient mice, MMNK-1 cells developed bile duct-like structures in the spleen. After LPS treatment, MMNK-1 cells produced interleukin-6 and failed to form well-developed tubular structures in Matrigel. CONCLUSION: We have established an immortalized cholangiocyte cell line, MMNK-1, using SV40T and hTERT transduction.

Animals↗

PubMed2004

A new cell-permeable peptide allows successful allogeneic islet transplantation in mice.

Calcineurin inhibitors such as cyclosporine A and FK506 have been used for transplant therapy and treatment of autoimmune diseases. However, the inhibition of calcineurin outside the immune system has a number of side effects, including hyperglycemia. In the search for safer drugs, we developed a cell-permeable inhibitor of NFAT (nuclear factor of activated T cells) using the polyarginine peptide delivery system. This peptide provided immunosuppression for fully mismatched islet allografts in mice. In addition, it did not affect insulin secretion, whereas FK506 caused a dose-dependent decrease in insulin secretion. Cell-permeable peptides can thus provide a new strategy for drug development and may eventually be useful clinically.

Animals↗

PubMed2004

Telomerase-specific replication-selective virotherapy for human cancer.

PURPOSE: Replication-selective tumor-specific viruses present a novel approach for treating neoplastic disease. These vectors are designed to induce virus-mediated lysis of tumor cells after selective viral propagation within the tumor. Telomerase activation is considered to be a critical step in carcinogenesis, and its activity is closely correlated with human telomerase reverse transcriptase (hTERT) expression. We investigated the antitumor effect of the hTERT-specific replication-competent adenovirus on human cancer cells. EXPERIMENTAL DESIGN: We constructed an adenovirus 5 vector [tumor- or telomerase-specific replication-competent adenovirus (TRAD)], in which the hTERT promoter element drives expression of E1A and E1B genes linked with an internal ribosome entry site, and we examined the selective replication and antitumor effect in human cancer cells in vitro and in vivo. RESULTS: TRAD induced selective E1A and E1B expression in human cancer cells, but not in normal cells such as human fibroblasts. TRAD replicated efficiently and induced marked cell killing in a panel of human cancer cell lines, whereas replication as well as cytotoxicity was highly attenuated in normal human fibroblasts lacking telomerase activity. In nu/nu mice carrying s.c. human lung tumor xenografts, intratumoral injection of TRAD resulted in a significant inhibition of tumor growth. No evidence of TRAD was identified in tissues outside of the tumors, despite the presence of TRAD in the circulation. Moreover, TRAD replication in the distant, noninjected tumors was demonstrated. CONCLUSIONS: Our results suggest that the hTERT promoter confers competence for selective replication of TRAD in human cancer cells, an outcome that has important implications for the treatment of human cancers.

Adenoviridae↗

PubMed2004

The current situation in human pancreatic islet transplantation: problems and prospects.

In 2000, seven cases of pancreatic islet transplantation were documented by the researchers at the University of Alberta (Edmonton, Canada). The transplantation was performed using a protocol with a novel immunosuppressive regimen later named the Edmonton Protocol. The results showed that all seven patients became free of the need for insulin therapy. The success of the Edmonton Protocol has enhanced expectations for and interest in islet transplantation all over the world. Islet transplantation seems to be an almost ideal therapy for insulin-dependent patients. In our recent participation in transplant-related conferences in Europe or the USA, we have felt great enthusiasm for islet transplantation among clinicians, researchers, as well as medical staff. In Japan, the Organ Transplant Law that allows transplants from brain-dead patients was enacted in 1997. Since the passing of the law, people's interest in tissue and organ transplantation, particularly islet transplantation, has been growing. Here we present general information on islet transplantation and discuss its problems and prospects.

Animals↗

PubMed2004

Development of a porcine model of type 1 diabetes by total pancreatectomy and establishment of a glucose tolerance evaluation method.

PURPOSE: To develop and evaluate the efficacy of diabetes-targeted cell therapies in humans, a reliable model in larger animals is highly desirable. This article reports the surgical technique of total pancreatectomy in pigs and the biochemical analysis of the characteristics of totally pancreatectomized pigs. METHODS: Surgical total pancreatectomy was conducted in 23 pigs. Blood glucose, insulin, biochemistries, activity index, and intravenous glucose tolerance test (IVGTT) were examined to assess the pathophysiological profiles of diabetic pigs. RESULTS: A total of 14 pigs successfully underwent total pancreatectomy without requiring biliary reconstruction and were analyzed in the present study. Activity index was decreased from day 5 on and the mean survival of totally pancreatectomized pigs was 7.6 +/- 2.7 days. No endogenous insulin secretion was confirmed in these pigs. Pigs which received total pancreatectomy demonstrated significantly higher levels of ketone bodies. IVGTT performed within 4 days after total pancreatectomy showed a spontaneous decrease in blood glucose levels despite an absence of endogenous insulin secretion. IVGTT on day 5 or later showed continued hyperglycemia in pigs with total pancreatectomy. Histological examination showed atrophy of hepatocytes and decreased glycogen storage in the liver and decreased mucus production of the small intestine. CONCLUSION: This article describes a porcine model of diabetes created by total pancreatectomy and it analyzes the pathophysiological profiles in the animals. The present study has suggested that IVGTT on day 5 or later after total pancreatectomy is a reliable method to evaluate the efficacy of cell therapies.

Alanine Transaminase↗

PubMed2004

Maintenance of glucose-sensitive insulin secretion of cryopreserved human islets with University of Wisconsin solution and ascorbic acid-2 glucoside.

Normal human islet cells are an ideal source for pancreas-targeted cell therapies, but the availability of human donor pancreata for islet isolation is severely limited. To effectively utilize such scarce donor organs for cell therapies, it is crucial to develop an excellent isolation, effective cryopreservation, and efficient gene transfer techniques for the transportation of isolated cells. In the present study, we investigate the effect of University of Wisconsin (UW) solution and ascorbic acid-2 glucoside (AA2G) on the cryopreservation of human islets. We also evaluate the gene transfer efficiency of a lentiviral vector expressing the E. coli LacZ gene, Lt-NLS/LacZ, in human islets. Human islets were isolated with a standard digestion method at the University of Alberta. Isolated islets were transported to Japan for 40 h and then subjected to cryopreservation experiments. The following preservation solutions were tested: UW solution with 100 micro g/mL of AA2G, UW solution, 100% fetal bovine serum (FBS), and CMRL supplemented with 10% FBS. Following three months of cryopreservation, the islets were thawed and analyzed for viability, glucose-sensitive insulin secretion, proinsulin gene expression profile, and in vivo engraftment. The islets were also subjected to monolayer formation with 804G-cell-line-derived extracellular matrix (ECM), followed by Lt-NLS/LacZ transduction. The viability, morphology, glucose-sensitive insulin secretion, proinsulin gene expression, and monolayer formation efficiency of the thawed cryopreserved islets are significantly better maintained by the use of UW solution. When AA2G (100 microg/mL) is combined with UW, such parameters are further improved. The adequate engraftment of UW + AA2G-cryopreserved human islets is achieved in the liver of nude mice. Efficient Lt-NLS/LacZ transduction is identified in monolayered islets cryopreserved with UW solution with AA2G. The present work demonstrates that the combination of UW solution with AA2G (100 microg/mL) would be a useful cryopreservation means for human islets. Human islets monolayer-cultured with 804G-derived ECM are efficiently transduced with a lentiviral vector Lt-NLS/LacZ.

Adenosine↗

PubMed2004

Lentivirus-based gene delivery in mouse embryonic stem cells.

BACKGROUND: Embryonic stem (ES) cells are widely used in therapeutic research as an unlimited source of cell therapy. Therefore, it is of great value to find a way to efficiently manipulate ES cells. HIV-1-derived lentiviral vectors are now considered to be an efficient vehicle for delivering genes into a variety of cells. In this study, we examined the efficacy of lentivirus-based gene delivery into mouse ES (mES) cells. MATERIALS AND METHODS: Recombinant HIV-I-based lentiviral vectors Lt-GFP, expressing green fluorescent protein (GFP), and Lt-LacZ, expressing E. coli LacZ gene in conjunction with neomycin resistance gene, were generated using a FuGENE 6 transduction method and used for transducing ES cells derived from 129Sv mice. Lentiviral transduction efficacy was evaluated by GFP expression assay using flow cytometry and by X-gal staining. The in vivo potential of developing teratoma of such transduced mES cells was examined in severe combined immunodeficiency (SCID) mice. RESULTS: FuGENE 6 showed no considerable transduction-associated cytotoxicity. The expression rate of GFP and LacZ of mES cells increased on a multiplicity of infection (MOI)-dependent manner with the amount of Lt-GFP and Lt-LacZ used. Approximately 42% of mES cells were positive for GFP after infection of Lt-GFP at an MOI of 30. Notably, after G418 selection, nearly 100% of Lt-LacZ-transduced mES cells were positive for LacZ and formed teratomas in SCID mice. CONCLUSIONS: This work demonstrates that HIV-I-based lentiviral vectors are capable of transducing mES cells. Lentiviral vectors may facilitate an advance in the field of gene transfer and expression in various types of ES cells, including human ES cells.

Animals↗

PubMed2004

Transplantation of reversibly immortalized insulin-secreting human hepatocytes controls diabetes in pancreatectomized pigs.

Type 1 diabetes results from the destruction of insulin-producing pancreatic beta-cells by a beta-cell-specific autoimmune process. Although converting other cell types into insulin-producing cells may compensate for the loss of the beta-cell mass while evading beta-cell-specific T-cell responses, proof-of-principle of this approach in large animal models is lacking. This investigation was initiated to determine whether an insulin-producing human hepatocyte line can control diabetes when transplanted into totally pancreatectomized diabetic pigs. We established a reversibly immortalized human hepatocyte line, YOCK-13, by transferring a human telomerase reverse transcriptase cDNA and a drug-inducible Cre recombinase cassette, followed by cDNA for a modified insulin under the control of the L-type pyruvate kinase (L-PK) promoter. YOCK-13 cells produced small amounts of modified insulin and no detectable endogenous L-PK at low glucose concentrations, whereas they produced large amounts of both modified insulin and L-PK in response to high glucose concentrations. Xenotransplantation of YOCK-13 cells via the portal vein into immunosuppressed, totally pancreatectomized pigs decreased hyperglycemia and prolonged survival without adverse effects such as portal thrombosis, liver necrosis, pulmonary embolism, and tumor development. We suggest that this reversibly immortalized, insulin-secreting human hepatocyte line may overcome the shortage of donor pancreata for islet transplantation into patients with type 1 diabetes.

Animals↗

PubMed2004

[Liver-targeted regenerative medicine].

Recently, much attention has been drawn to liver-targeted regenerative medicine for the treatment of liver failure. Researchers in various fields consider that the following cells can be used for such therapy: human embryonic stem (ES) cells, somatic stem cells, hepatic stem cells, small hepatocytes, bone marrow- and cord blood-derived hepatic progenitor cells, and human hepatocyte cell lines. The Cre/loxP-based reversible immortalization of human hepatocytes is also introduced in this review article. Here we describe the candidates that can contribute to hepatic regeneration. This reversible immortalization system allows us to establish a highly safe human hepatocyte line that is capable of differentiation at a lower cost and on a larger scale.

Cell Transplantation↗

PubMed2004

Arg-Gly-Asp (RGD) peptide ameliorates carbon tetrachloride-induced liver fibrosis via inhibition of collagen production and acceleration of collagenase activity.

Liver cirrhosis is caused by a relative imbalance between synthesis and degradation of collagens. Arg-Gly-Asp (RGD) peptide is a major adhesive domain of several extracellular matrix (ECM) components, such as that involved in the binding of fibronectin to the alpha5beta1 integrin receptor. We previously reported that RGD peptide increased the expression of matrix metalloproteinase in hepatic stellate cells (HSCs) which play a major role in hepatic fibrosis. We evaluated whether RGD-peptides inhibit the progression of liver fibrosis in an animal model of carbon tetrachloride-induced hepatotoxicity. RGD peptide (GRGDS) (1 mg/kg body weight) was injected intraperitoneally (i.p.) 3 times a week for one month. The group treated with control peptide (GRGES) showed pathologically typical hepatic fibrosis, while the RGD-treated group showed minimal fibrotic changes. The liver contents of collagen and hydroxyproline in the RGD-treated group was significantly lower than that of the control group. Collagenase activity measured in liver homogenates was significantly higher in the treated group than in the control group. In an in vitro study using TWNT-4 cells derived from human HSCs, RGD peptide (100 mug/ml) reduced the expression of type I collagen and tissue inhibitor of matrix metalloproteinase-1, and increased that of matrix metalloproteinase-1. These results indicated that RGD peptides inhibited liver fibrosis associated with both decreased collagen production and increased collagenase acitivity, and suggested that RGD peptide might be useful for the therapy of hepatic fibrosis.

Animals↗

PubMed2003

Establishment of immortalized human hepatic stellate scavenger cells to develop bioartificial livers.

BACKGROUND: Maintenance of liver-specific functions has been shown to be stabilized by co-cultivation of hepatocytes with hepatic stellate cells (HSC). Because the limited lifespan of human HSC is a major hurdle to their use, the authors report here the amplification of human HSC populations in vitro by retroviral transfer of human telomerase reverse transcriptase (hTERT). METHODS: Human HSC strain LI 90 cells were transduced with a retroviral vector SSR#197 expressing hTERT and green fluorescent protein (GFP) cDNA flanked by a pair of loxP. TWNT-1, one of SSR#197-immortalized HSC, was characterized. Differentiated liver functions were evaluated in an immortalized human hepatocyte NKNT-3-TWNT-1 co-culture system. RESULTS: TWNT-1 cells showed differential functions of HSC, including uptake of acetylated low-density lipoproteins and synthesis of collagen type I and hepatocyte growth factor. Efficient excision of the retrovirally transferred hTERT and GFP cDNAs was achieved by TAT-mediated expression of the Cre recombinase and subsequent GFP-negative cell sorting. When co-cultured with TWNT-1 cells, NKNT-3 increased protein expression of the detoxifying cytochrome P450-associated protein isoenzymes 3A4 and 2C9 and urea synthesis. CONCLUSIONS: TWNT-1 cells could be valuable in the study of integrated liver functions and contribute to the optimization of liver cell therapies and bioartificial livers.

Acetylation↗

PubMed2003

Hybrid bioartificial liver: establishing a reversibly immortalized human hepatocyte line and developing a bioartificial liver for practical use.

Recently, much attention has been attracted by a novel therapy for liver failure using a hybrid bioartificial liver (BAL) support device that incorporates living liver cells. Researchers in various fields have considered the following cells for potential use in BALs: human embryonic stem (ES) cells; somatic stem cells; differentiated tissue cells; and cells derived from tissues of different animal species, particularly from the pig. With their pluripotency, human ES cells are extremely useful, and many research groups are joining the race to develop BALs. One such effort involves the breeding of transgenic pigs to overcome interspecies barriers. Recent reports suggest, however, that porcine endogenous retrovirus may infect human tissues, and clinical application of transgenic pigs has become a controversial issue. To avoid such risks, we recommend that researchers adopt a reversible immortalization system that uses the Cre-loxP site-specific recombination reaction targeting human hepatocytes in their final differentiated state. This system has allowed us to establish a safe human hepatocyte line that is capable of differentiation at low cost and on a large scale. We are also designing and developing an artificial liver module made of a combination of hollow fibers and nonwoven fabrics. The objective of this review article is to report our therapeutic strategy, which aims at the earliest possible introduction of the treatment of liver failure using BALs.

Animals↗

PubMed2003

Cell choice for bioartificial livers.

It is unlikely that human hepatocytes can be isolated on a scale sufficient to treat more than a fraction of the patients who need bioartificial liver (BAL) treatment. The use of animal cells results in the concerns related to the transmission of infectious pathogens and immunologic and physiologic incompatibilities between the donor and humans. Human embryonic stem cells and bone marrow multipotent adult progenitor cells have received great attention as a possible source for BALs. The use of tightly regulated clonal hepatocyte cell lines would be attractive. Such cell lines grow economically in tissue culture and provide the advantage of uniformity, sterility, and freedom of pathogens. In this paper, the authors review the choice of cells for BALs and discuss our reversible immortalization system of human liver cells using a retroviral transfer of immortalizing genes and subsequent Cre/loxP-mediated site-specific recombination.

Animals↗

PubMed2003

Establishment of an immortalized human hepatic stellate cell line to develop antifibrotic therapies.

Because human hepatic stellate cells (HSCs) perform a crucial role in the progress of hepatic fibrosis, it is of great value to establish an immortalized human cell line that exhibits HSC characteristics and grows well in tissue cultures for the development of antifibrotic therapies. Thus, we engineered an immortalized human hepatic stellate cell (HSC) line TWNT-4 by retrovirally inducing human telomerase reverse transcriptase (hTERT) into LI 90 cells established from a human liver mesenchymal tumor. Parental LI 90 entered replicative senescence, whereas TWNT-4 showed telomerase activity and proliferated for more than population doubling level (PDL) 200 without any crisis. TWNT-4 expressed platelet-derived growth factor-beta receptor (PDGF-betaR), alpha-smooth muscle actin (alpha-SMA), and type I collagen (alpha1) and was considered to be an activated form of HSCs. Treatment of TWNT-4 cells with either 100 U/ml of IFN-gamma or 1 ng/ml of rapamycin (Rapa) for 14 days led to lower expression of type I collagen (alpha1) at RNA and protein levels. Exposure of TWNT-4 cells to both of IFN-gamma (10 U/ml) and Rapa (0.1 ng/ml) for 14 days effectively decreased the expression of type I collagen (alpha1), PDGF-betaR, and alpha-SMA expression and suppressed TGF-beta1 secretion of TWNT-4 cells. We successfully induced apoptosis by transducing TNF-related apoptosis-inducing ligand (TRAIL) into TWNT-4 cells using adenovirus vectors Ad/GT-TRAIL and Ad/PGK-GV-17. These findings suggested that immortalized activated HSC line TWNT-4 would be a useful means to develop antifibrotic therapies.

Actins↗

PubMed2003

Hepatocyte isolation and transplantation in the pig.

Hepatocyte transplantation (HTX) has received great expectation for the treatment of a wide spectrum of liver diseases. Considering the severe shortage of human livers for hepatocyte isolation, porcine hepatocytes are an attractive alternative to normal human hepatocytes. To develop such therapy, establishment of an efficient hepatocyte isolation and transplantation model that enables accurate assessment of safety and efficacy of HTX is extremely important. Porcine hepatocytes were isolated from a surgically removed liver segment with a four-step retrograde perfusion using dispase and collagenase. The resultant hepatocytes of > 84% viability were used for transplantation experiment in a pig model of acute liver failure induced by intravenous administration of D-galactosamine (D-gal) (0.5 mg/kg). Twenty-four hours after D-gal injection, transplantation of freshly isolated porcine hepatocytes (1 x 10(9)) was safely conducted and prolonged the survival of D-gal-treated pigs. We describe an efficient porcine hepatocyte isolation and subsequent cell transplantation in pigs with D-gal-induced liver failure.

Animals↗