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Teru Okitsu

Publications and source records attributed to Teru Okitsu.

At least 37 records · Page 2Linked to original sources

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↗

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↗

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↗

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↗

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↗

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↗

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↗

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↗

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↗

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↗

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↗

Maintenance of cold-preserved porcine hepatocyte function with UW solution and ascorbic acid-2 glucoside.

Normal human hepatocytes are an ideal source of liver-targeted cell therapies, such as hepatocyte transplantation and bioartificial livers, but availability of human donor livers for liver cell isolation is severely limited. To effectively utilize scarce donor organs for cell therapies, it is of extreme importance to establish an efficient isolation technique and an effective cold preservation solution for transportation of isolated cells. A lateral segment of the liver was surgically resected from pigs weighing 10 kg and a four-step collagenase and dispase digestion was conducted. Isolated hepatocytes were subjected to 8-h cold storage on ice. The following preservation solutions were tested: 1) University of Wisconsin (UW) solution, 2) UW with 100 microg/ml of ascorbic acid-2 glucoside (AA2G), 3) 100% fetal bovine serum (FBS), and 4) Dulbecco's modified Eagle's medium (DMEM) supplemented with 100% FBS. The mean viability of porcine hepatocytes was 95.5 +/- 2.5% when isolated in three independent experiments. Viability, plating efficiency, membrane stability, and ammonia metabolic capacity of cold-preserved hepatocytes were significantly better maintained by the use of UW solution. When AA2G (100 microg/ml) was combined with UW solution, such parameters were further improved. It was explained by inhibition of caspase-3 activation and retention of ATP at high levels of hepatocytes preserved with UW solution containing AA2G. The present work demonstrates that a combination of UW solution with AA2G (100 microg/ml) would be a useful cold preservation means for the development of cell therapies.

Adenosine↗

Cryopreservation of primarily isolated porcine hepatocytes with UW solution.

Development of liver-targeted cell therapies, such as hepatocyte transplantation and bioartificial livers, requires a large amount of functional hepatocytes as needed. To achieve this development, establishing an excellent cryopreservation method of hepatocytes is an extremely important issue. Therefore, we performed a comparative review of cryoprotective effects of various cryopreservation solutions using primarily isolated porcine hepatocytes. Porcine hepatocytes were isolated with a four-step dispase and collagenase perfusion method. The obtained hepatocytes with the initial viabilities of 76%, 84%, and 96% were assigned to the following four groups for cryopreservation at -80 degrees C: Dulbecco's modified Eagle's medium (DMEM) + 10% fetal bovine serum (FBS) + 12% dimethyl sulfoxide (DMSO) (group A), University of Wisconsin (UW) solution + 12% DMSO (group B), Cell Banker 1 (group C), and Cell Banker 2 (group D). The hepatocytes in each group were thawed at 3 days, 10 days, and 5 months of cryopreservation and subjected to comparative analyses, including viability, plating efficiency, LDH release, ammonia removal test, and lentiviral gene transfer. These parameters were the most favorable in the hepatocytes cryopreserved with UW solution. Approximately 5% of thawed cryopreserved porcine hepatocytes expressed LacZ activity after lentiviral transduction. Intrasplenic transplantation of UW solution-cryopreserved hepatocytes improved the survival of rats treated with D-galactosamine. UW solution maintained the functions of cryopreserved porcine hepatocytes.

Adenosine↗

Controlled expansion of human endothelial cell populations by Cre-loxP-based reversible immortalization.

Endothelial cells (ECs) play multiple physiological functions and are central to many pathological processes. Various biological studies as well as cell and gene therapy applications would benefit substantially from a procedure that would result in the expansion in culture of large numbers of highly differentiated human ECs. Here, we report the amplification in vitro of human EC populations, which occurred during the first phase of reversible immortalization resulting from the retroviral transfer of an oncogene that was subsequently excised by Cre-loxP-mediated site-specific recombination. Human umbilical vein endothelial cells (HUVECs) and human liver sinusoidal endothelial cells (HLSECs) were transduced with a retroviral vector that expresses the simian virus 40 large T (SV40T) gene flanked by positive and negative selectable markers and a pair of loxP recombination targets. Transduced HUVECs and HLSECs yielded clones with greatly extended life spans, referred to as HNNT-1 and HNNT-2 cells, respectively. HNNT-1 and HNNT-2 cells showed morphological characteristics of ECs and were maintained in culture up to population doubling level (PDL) 80 for HNNT-1 and PDL 65 for HNNT-2 cells. HNNT-1 and HNNT-2 cells were not tumorigenic when transplanted into severe combined immunodeficiency mice and were sensitive to ganciclovir as well as G418. Both cell clones expressed EC markers, which include factor VIII, VEGF receptors (Flt-1 and KDR/Flk-1), and CD34, and endocytosed acetylated low-density lipoproteins. Formation of capillary-like structures in a Matrigel assay was observed with HNNT-1 and HNNT-2 cells until at least PDL 50. Complete elimination of the transferred SV40T gene was achieved in virtually 100% of HNNT-1 and HNNT-2 cells after infection with a recombinant adenovirus expressing the Cre recombinase fused to a nuclear localization signal and subsequent selection with G418. Reverted cells maintained their differentiated EC phenotype. This study extends the utility of the reversible immortalization procedure and provides a means to expand primary human ECs of various sources for basic studies and possible cell and gene therapies.

Animals↗

UW solution: a promising tool for cryopreservation of primarily isolated rat hepatocytes.

Cryopreserved hepatocytes are a ready source of metabolic and synthetic functions for hepatocyte transplantation and bioartificial livers. In this study, we evaluated a cytoprotective effect of University of Wisconsin (UW) solution during cryopreservation of rat hepatocytes. We also investigated the feasibility of lentivirus-based gene transfer into thawed hepatocytes after cryopreservation. Primary rat hepatocytes were isolated using a two-step collagenase perfusion technique, and the resulting hepatocytes with more than 85% viability assessed by a trypan blue exclusion test were subjected to the present study. These cells were subjected to the present study. Cells were cryopreserved with UW solution containing 10% fetal bovine serum (FBS) with 12% dimethylsulfoxide (DMSO) (group 1, G1), Cellbanker solution (group 2, G2), and 10% FBS-containing Dulbecco modified Eagle medium (DMEM) with 12% DMSO (group 3, G3). After thawing the cryopreserved hepatocytes, cell viability, plating efficiency, morphological appearance, and ammonia clearance activity were determined for each group. The efficacy of lentivirus-mediated Escherichia coli LacZ gene delivery was evaluated. Hepatocyte viabilities after 3- and 7-day cryopreservation were 73.2% and 62.5% for G1, 57.5% and 46.5% for G2, and 57.3% and 41.5% for G3, respectively. Plating efficiency and ammonia clearance activity were improved in G1 hepatocytes compared to G2 and G3 cells. Lentiviral transfer of a LacZ gene was confirmed in the thawed hepatocytes after cryopreservation by an X-gal stain assay.

Adenosine↗

Transduction of immortalized human hepatocytes with p21 to enhance differentiated phenotypes.

We previously constructed an immortal human hepatocyte line NKNT-3 with a simian virus 40 T antigen (SV40T) to develop cell-based biological therapies. p21 is a molecule that regulates the transition from the G1 phase to the S phase of the cell cycle. Investigators have demonstrated that overexpression of p21 induces differentiation in various cell lines. In the current study we examined the effect of p21 on differentiated phenotypes of SV40T-immortalized NKNT-3 cells. A replication-deficient adenovirus vector expressing a human wild-type p21 cDNA under the control of the CMV promoter (Ad5CMVp21) and a human wild-type p21 protein fused to the protein transduction domain from the human immunodeficiency virus (HIV) TAT protein (TAT/p21) were utilized to achieve efficient delivery of p21 into NKNT-3 cells. Morphological alterations, cell cycle progression, and expression of albumin and p-450 associated enzymes (CYPs) 3A4 and 2C9 were evaluated in NKNT-3 cells treated with Ad5CMVp21 and TAT/p21. Efficient adenovirus-based p21 transfer and TAT-mediated p21 protein delivery were confirmed in NKNT-3 cells in an immunofluorescence study and Western blotting analysis. Transduction of NKNT-3 cells with p21 predominantly arrested the cell cycle at the G1 checkpoint, resulting in differentiated hepatic phenotypes in morphology and improvement in protein expression of albumin, CYP 3A4, and CYP C29. We here show that exogenous expression of p21 augments cellular differentiation in immortalized human NKNT-3 cells.

Albumins↗

Lentiviral transfer of the LacZ gene into human endothelial cells and human bone marrow mesenchymal stem cells.

Because one of the attractive characteristics of human immunodeficiency virus type 1 (HIV-1)-based lentiviral vectors is that it can infect even nondividing cells, a lentivirus-mediated gene delivery system is currently being paid a great deal of attention as an innovative tool for gene transfer into target cells. The purpose of the work was to investigate the efficacy of lentiviral transfer of the LacZ gene into human umbilical vein endothelial cells (HUVECs) and human bone marrow mesenchymal stem cells (HMSCs) in vitro. For the present study, a vesicular stomatitis virus G-protein (VSV-G)-pseudotyped lentiviral vector encoding the E. coli LacZ gene tagged with nuclear localization signal (NLS) was generated in 293T cells by means of the three-plasmid system. The resulting lentiviral vector, LtV-NLS/LacZ, was allowed to infect HUVECs and HMSCs. Approximately 70% of HUVECs were positive for LacZ expression and 50% of HMSCs showed LacZ activity. There was no significant difference in transduction efficacy between early and late-passage phases in both cells. LtV-NLS/LacZ-transduced HUVECs showed gene expression of endothelial markers including CD34 and flt-1 and KDR/flk-1 of vascular endothelial growth factor (VEGF) receptors and had angiogenic potential as efficiently as primarily cultured HUVECs in a Matrigel assay. These findings provide evidence that lentiviral vectors are efficient tools for gene transfer and expression in human endothelial cells and stem cells that could be useful for tissue engineering.

Animals↗

Insulin independence after living-donor distal pancreatectomy and islet allotransplantation.

Rising demand for islet transplantation will lead to severe donor shortage in the near future, especially in countries where cadaveric organ donation is scarce. We undertook a successful transplantation of living-donor islets for unstable diabetes. The recipient was a 27-year-old woman who had had brittle, insulin-dependent diabetes mellitus for 12 years. The donor, who was a healthy 56-year-old woman and mother of the recipient, underwent a distal pancreatectomy. After isolation, 408 114 islet equivalents were transplanted immediately. The transplants functioned immediately and the recipient became insulin-independent 22 days after the operation. The donor had no complications and both women showed healthy glucose tolerance. Transplantation of living-donor islets from the distal pancreas can be sufficient to reverse brittle diabetes.

Adult↗