[Acute hemorrhagic colitis induced by the neuraminidase inhibitor oseltamivir].

A 23-year-old woman had lower abdominal pain, diarrhea and bloody stool was admitted and given a diagnosis of influenza B. Her home doctor had started treatment by neuraminidase inhibitor (oseltamivir) the previous day. Colonoscopic examination revealed an area of hemorrhage and erosion in the left transverse colon. After halting oseltamivir treatment these symptoms disappeared and her colonoscopic findings improved. A drug-induced lymphocyte stimulation test was positive for oseltamivir. This case is the first reported case of acute hemorrhagic colitis induced by oseltamivir.

Repetitive and safe transgene expression in rat liver is achievable by adenoviral infusion into the common bile duct.

To examine the feasibility of adenovirus-mediated gene transfer into the liver, we examined whether adenoviral infusion into the common bile duct could induce repetitive and safe transgene expression in rat livers. Recombinant adenovirus carrying a reporter lacZ gene was repetitively infused retrogradely into the common bile duct of rats. LacZ expression in rat livers was estimated histochemically by X-gal staining and quantitatively by a chemiluminescent reporter gene assay after the first, second and third adenoviral infusion into the common bile duct. To assess the safety of repetitive adenoviral infusion into the common bile duct, various liver- and kidney-related serum parameters, and liver damage were examined biochemically and histologically, respectively. Retrograde adenoviral infusion into the common bile duct achieved sufficient and safe lacZ expression in rat livers. Although transgene expression in the liver was transient, the second and third adenoviral infusion into the common bile duct could induce the expression of the same transgene in the liver. Furthermore, repetitive adenoviral infusion into the common bile duct caused no significant reverse reactions. Because retrograde adenoviral infusion into the common bile duct is a clinically practical method by using a widely used endoscopic technique, namely endoscopic retrograde cholangiography, these results suggest that retrograde adenoviral infusion into the common bile duct is a practical gene therapy modality in clinical settings.

Combination of interferon-beta and angiotensin-converting enzyme inhibitor, perindopril, attenuates the murine liver fibrosis development.

Recent studies have revealed that both interferon (IFN) and angiotensin-converting enzyme inhibitor (ACE-I) exert an anti-fibrotic effect. The aim of this study was to examine the combined effect of the ACE-I and IFN on the murine hepatic fibrosis development. A model of CCl(4)-induced hepatic fibrosis was used to assess the effect of the clinically used ACE-I, perindopril (PE), and IFN-beta. The PE and IFN were administered after 2-week treatment with CCl(4), and the hepatic indices of fibrosis were assessed at 8 weeks. Single treatment with either PE or IFN at the clinically available comparable doses significantly attenuated liver fibrogenesis associated with suppression of the hepatic hydroxyproline and serum fibrosis markers. The number of alpha-smooth muscle actin-positive cells, and the hepatic alpha1(I)-procollagen mRNA were also markedly inhibited. The inhibitory effect of PE was more potent than IFN, and the combination treatment with PE and IFN almost completely attenuated liver fibrosis development. In vitro, the angiotensin-II (AT-II) type 1 receptor blocker and IFN suppressed the AT-II-induced proliferation and alpha1(I)-procollagen mRNA expression of the activated hepatic stellate cells. The combination treatment of the clinically used PE and IFN may provide a new strategy for anti-liver fibrosis therapy.

Involvement of the vascular endothelial growth factor receptor-1 in murine hepatocellular carcinoma development.

BACKGROUND/AIMS: The role of the vascular endothelial growth factor receptor-1 (VEGFR-1) in hepatocellular carcinoma (HCC) development has not been elucidated yet. The aim of this study was to examine the role of VEGFR-1 in VEGF-mediated HCC development and angiogenesis as compared to that of VEGFR-2. METHODS: We examined the effects of VEGFR-1, and VEGFR-2 neutralizing monoclonal antibodies (R-1mAb and R-2mAb, respectively) on VEGF-mediated HCC development both in an allograft and orthotopic models. RESULTS: In the allograft model, both R-1mAb and R-2mAb significantly attenuated the VEGF-mediated tumor development in a dose dependent manner with associated reduction of angiogenesis in the tumor. The inhibitory effect of R-2mAb was more potent than that of R-1mAb, and the combination treatment with both mAbs almost completely attenuated VEGF-mediated HCC development. Immunohistochemical analysis revealed that apoptosis increased markedly in the tumor. Furthermore, these inhibitory effects with both mAbs were achieved even on established tumors and orthotopic transplantation. CONCLUSIONS: In addition to VEGFR-2, VEGFR-1 also lies on the signal transduction pathway by which VEGF augments HCC development and angiogenesis not only at the initial stage but also in the established tumor.

Halting the interaction between vascular endothelial growth factor and its receptors attenuates liver carcinogenesis in mice.

It has been shown that angiogenesis plays an important role not only in tumor growth, but also in early carcinogenesis. The expression of a potent angiogenic factor, vascular endothelial growth factor (VEGF), increased during the early stage of carcinogenesis. In this study, the effects of the neutralizing monoclonal antibodies R1 mAb and R2 mAb of the VEGF receptors Flt-1 (VEGFR-1) and KDR/Flk-1 (VEGFR-2), respectively, on murine hepatocarcinogenesis induced by diethylnitrosamine (DEN) were examined. The effects of R1 mAb and R2 mAb on spontaneous lung metastasis from hepatocellular carcinoma (HCC) were also investigated. VEGF expression and neovascularization in the tumor increased stepwise during hepatocarcinogenesis. Treatment with both R1 mAb and R2 mAb markedly inhibited the development of HCC and adenoma in the liver. The inhibitory effect of R2 mAb was more potent than that of R1 mAb, and the combination treatment with both mAbs almost completely attenuated hepatocarcinogenesis. Both R1 mAb and R2 mAb treatment significantly suppressed the development of angiogenesis in HCC. The suppressive effects against angiogenesis R1 mAb and R2 mAb were similar in magnitude to their inhibitory effects against hepatocarcinogenesis. Furthermore, spontaneous lung metastasis from HCC was also significantly suppressed by R1 mAb and R2 mAb treatment. In conclusion, these results suggest that VEGF and receptor interaction plays an important role in hepatocarcinogenesis and in spontaneous lung metastasis from HCC.

Combination of interferon-beta and the angiotensin-converting enzyme inhibitor, perindopril, attenuates murine hepatocellular carcinoma development and angiogenesis.

PURPOSE: Angiogenesis is now recognized as a crucial step in the development of tumors, including hepatocellular carcinoma (HCC). The aim of this study was to elucidate the combined effect of the clinically used angiotensin I-converting enzyme (ACE) inhibitor, perindopril (PE), and IFN-beta on the development and angiogenesis of murine HCC at clinically comparable low doses. EXPERIMENTAL DESIGN: PE and IFN were administered at doses of 2 mg/kg/day and 1 x 10(4) IU/twice a week, respectively. RESULTS: Both PE and IFN significantly suppressed HCC development and inhibited neovascularization in the tumor, although the effect of low-dose IFN was weaker than that of PE. A combination regimen of PE plus IFN was effective; IFN significantly augmented the tumoricidal effect of PE. These inhibitory effects of PE plus IFN could be detected even on established tumors. The potent angiogenic factor, vascular endothelial growth factor, was markedly suppressed by combined treatment with PE and IFN, whereas these agents produced a marked increase of apoptosis in the tumor. The in vitro studies exhibited that PE and IFN inhibited endothelial cell tubular formation. IFN also suppressed endothelial cell proliferation, whereas neither IFN nor PE showed any inhibitory effect on proliferation of HCC cells. CONCLUSION: The combination treatment of PE and IFN at clinically comparable low doses could inhibit HCC development and angiogenesis and suppress vascular endothelial growth factor as well. Because both agents are widely used in clinical practice, this combination regimen may represent a potential new strategy for HCC therapy in the future.

Angiotensin-II induces the tissue inhibitor of metalloproteinases-1 through the protein kinase-C signaling pathway in rat liver fibrosis development.

It has been shown that tissue inhibitor of metalloproteinases-1 (TIMP-1) plays an important role in the progression of liver fibrosis. TIMP-1 gene expression is regulated by several factors in vivo. Among them, angiotensin-II (AT-II) induces TIMP-1 in endothelial cells (EC) in vitro, however, the interaction between these molecules in liver fibrogenesis has not yet been elucidated. The aim of this study was to examine a possible association between TIMP-1 and AT-II both in vitro and in vivo using the clinically available angiotensin-I converting enzyme (ACE) inhibitor, perindopril (PE), and the AT-II type 1 receptor blocker (ARB), candesartan (CA). In cultured activated hepatic stellate cells (HSC), AT-II increased TIMP-1 in a dose- and time-dependent manner. CA and LY 333531, the protein kinase C (PKC) inhibitor, blocked this augmentation in a dose-dependent manner. In the CCl(4)- and pig serum-induced rat liver fibrosis model, a clinically comparable low dose of PE and CA significantly suppressed liver fibrosis development associated with the suppression of TIMP-1 expression in the liver. AT-II induces TIMP-1 via type 1 receptor and PKC as an intracellular signaling pathway in activated HSC. These results suggested that the AT-II-induced TIMP-1 plays an important role in liver fibrosis development.

The copper-chelating agent, trientine, attenuates liver enzyme-altered preneoplastic lesions in rats by angiogenesis suppression.

It has been shown that angiogenesis plays an important role not only in tumor growth, but also in carcinogenesis. We previously reported that the copper-chelating agent, trientine dihydrochloride (trientine), exerted strong anti-angiogenic activity and inhibited hepatocellular carcinoma (HCC) tumor growth. The aim of the current study was to elucidate the effect of trientine on liver enzyme-altered preneoplastic lesions in rats, especially in conjunction with angiogenesis alteration in the liver. In a diethylnitrosamine (DEN)-induced rat hepatocarcinogenesis model, trientine treatment, even at a clinically comparable low dose, significantly suppressed glutathione S-transferase placental form (GST-P)-positive preneoplastic lesions associated with a decrease in copper content in the liver. Trientine also markedly suppressed neovascularization in the liver to a similar level as that of development of the preneoplastic lesions. On the contrary, the proliferative cell nuclear antigen (PCNA)-positive cells were not altered with or without trientine treatment. These results suggested that the copper-chelating agent, trientine, exerted chemopreventive effects against rat liver carcinogenesis due to the suppression of angiogenesis, and suggest that it might be useful clinically as a chemopreventive agent of HCC.

Extracellular matrix remodeling may predominate over hepatocyte injury in hepatocellular carcinoma development.

It has been suggested that both extracellular matrix (ECM) remodeling and persistent hepatocyte injury play important roles in liver carcinogenesis process. It is, however, still controversial which factor plays a predominant role. The aim of the present study was to examine the role of each factor in the liver enzyme-altered preneoplastic lesions, focusing on the relationship between the hepatocyte injury and fibrosis extension. The effects of two similar herbal medicines (Sho-saiko-to and Saiko-keishi-to: TJ-9 and TJ-10, respectively) were elucidated on the hepatocyte injury, fibrosis and preneoplastic lesions development using a choline-deficient-L-amino acid-defined (CDAA) diet rat liver carcinogenesis model. TJ-9 prevented fibrosis and glutathione S-transferase placental form (GST-P)-positive preneoplastic lesion development without reducing the hepatocyte injury as indicated by the serum markers. TJ-10 significantly protected against the hepatocyte injury. However, it did not exert any inhibitory effect on fibrosis and the development of preneoplastic lesions. Our in vitro study revealed that TJ-9 markedly suppressed the hepatic stellate cell activation whereas TJ-10 did not. These results suggested that the ECM remodeling plays a more important role than the persistent hepatocyte injury in the liver enzyme-altered preneoplastic lesion development in the rat.

Tissue inhibitor of metalloproteinases-1 (TIMP-1) inhibits tumor growth and angiogenesis in the TIMP-1 transgenic mouse model.

The tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) has been recognized as a multifunctional protein. The role of TIMPs in cancer remains the subject of conflicting reports with an antitumor activity or a tumor growth stimulation activity by several mechanisms. The aim of our study is to investigate the effect of ectopic TIMP-1 overexpression on the primary transplanted tumor growth. We employed transgenic mice overexpressing the human TIMP-1 (hTIMP-1) in the liver under control of the albumin promoter/enhancer (TIMP-Tg-mice) and producing high serum levels of TIMP-1. We used the transplantable Ehrlich tumor cells in the current study. The allograft study revealed that the tumor growth in the TIMP-Tg-mice was more significantly inhibited than control (Cont) mice by associated suppression of neovascularization in the tumor. The in vitro studies showed that the recombinant TIMP-1 (rTIMP-1) did not affect the proliferation of the endothelial cells (ECs) and tumor cells, suggesting that the tumor suppressive effect of TIMP-1 was not due to cytotoxicity. TIMP-1 significantly inhibited EC tubular formation in vitro. Furthermore, TIMP-1 treatment did not affect the levels of matrix metalloproteinase (MMP)-2 and MMP-9 mRNA in the Ehrlich tumor cells in vitro, although these expressions in the tumor were markedly suppressed in the TIMP-Tg-mice, compared to the Cont-mice at the end of the experiment. These results suggested that the ectopically overexpressed TIMP-1 inhibited the tumor growth by angiogenesis suppression.

Development of hepatocytes from ES cells after transfection with the HNF-3beta gene.

We have attempted to generate embryonic stem (ES) cell-derived hepatocytes expressing liver-specific functional properties by use of ES cell technology. It was found that ES cells are allowed to differentiate into hepatocytes possessing high metabolic activities when hepatocyte nuclear factor (HNF)-3beta-transfected ES cells are cultured in alpha-MEM medium supplemented with 10% fetal bovine serum (FBS) and fibroblast growth factor (FGF)-2 in the three-dimensional cell culture system at 5% CO2. The differentiated cells induced albumin, triacylglycerol, urea, and glycogen synthesis as well as further expression of metabolic proteins and serum factors as markers of hepatocytic differentiation for at least 4 months. The cells differentiated from HNF-3beta-transfected ES cells also had hepatocyte-like ultrastructural characteristics, including several endoplasmic reticula, mitochondrion, and glycogen. Our findings indicate that generation of hepatocytes maintaining high metabolic functions developed from mouse ES cells will facilitate the study of the basic mechanism for hepatogenesis and will certainly provide new opportunities for tissue transplantation.

Tissue inhibitor of metalloproteinases-1 attenuates spontaneous liver fibrosis resolution in the transgenic mouse.

It has been suggested that the tissue inhibitor of metalloproteinases-1 (TIMP-1) is involved in spontaneous resolution of liver fibrosis. The aim of this study was to investigate whether TIMP-1 altered spontaneous resolution of liver fibrosis in conjunction with matrix metalloproteinases (MMP) inhibition and hepatic stellate cell (HSC) activation. The livers of liver-targeted TIMP-1 transgenic (TIMP-Tg) and control hybrid (Cont) mice were harvested at 0, 3, 7, and 28 days following spontaneous recovery from CCl(4)-induced liver fibrosis. The extent of fibrosis resolution, MMP expression, alpha-smooth-muscle actin (alpha-SMA) positive cells, and procollagen-(I) messenger RNA (mRNA) in the liver were assessed at the respective periods in both groups. We also examined the effect of TIMP-1 on HSC apoptosis. The TIMP-Tg mice showed significantly attenuated resolution of spontaneous liver fibrosis compared with the Cont mice. The hydroxyproline content, number of alpha-SMA positive cells, and procollagen-(I) mRNA rapidly decreased with time in the Cont mice, whereas these markers were little changed in TIMP-Tg mice. The level of the active form of metalloproteinases-2 (MMP-2) in the TIMP-Tg mice was less than that in the Cont mice. TIMP-1 markedly decreased the nonparenchyma apoptotic cells in the liver fibrosis resolution model, and it also inhibited HSC apoptosis associated with suppression of caspase-3 activity in vitro. In conclusion, TIMP-1 significantly attenuated spontaneous resolution of liver fibrosis by the combination of a net reduction of the MMP activity and suppression of apoptosis in HSC.

Inhibition of renin-angiotensin system attenuates liver enzyme-altered preneoplastic lesions and fibrosis development in rats.

BACKGROUND/AIMS: It is suggested that the renin-angiotensin system (RAS) is involved in tumor development and fibrogenesis. The aim of the present study was to examine the effect of RAS inhibition on the liver enzyme-altered preneoplastic lesions and fibrosis development. METHODS: The effects of the clinically used angiotensin-I converting enzyme inhibitor (ACE-I), perindopril (PE), on two different rat model of liver carcinogenesis models induced separately by diethylnitrosamine (DEN) and a choline-deficient L-amino acid-defined (CDAA) diet were studied. This CDAA model was also used to elucidate the effect of PE on liver fibrosis development. RESULTS: The immunohistochemical evaluation revealed that the glutathione S-transferase placental form (GST-P), and gamma-glutamyltransferase (GGT)-positive preneoplastic foci significantly decreased in the livers of the PE-treated groups. In CDAA-induced liver fibrosis model, PE revealed a marked inhibitory effect of liver fibrosis development. The hepatic hydroxyproline, serum fibrosis markers, alpha-smooth muscle actin (alpha-SMA) immunopositive cells in number, and alpha-(III) pro-collagen mRNA expression were significantly suppressed by PE treatment. These inhibitory effects of PE were achieved even at a clinically comparable dose (2 mg/kg per day). CONCLUSIONS: These results suggested that the RAS is involved in liver carcinogenesis and fibrosis development.

Suppression of the renin-angiotensin system attenuates vascular endothelial growth factor-mediated tumor development and angiogenesis in murine hepatocellular carcinoma cells.

Angiotensin-II (AT-II), which is produced mainly by the renin-angiotensin system (RAS), has been shown to stimulate neovascularization. AT-II induces vascular endothelial growth factor (VEGF), which plays a pivotal role in tumor angiogenesis. The role of AT-II, however, in VEGF-mediated tumor development has not yet been elucidated. We examined the effect of RAS inhibition by angiotensin-I converting enzyme (ACE) inhibitor on VEGF-mediated tumor development and angiogenesis in a murine experimental model using a retroviral tetracycline-regulated (Retro-Tet) gene expression system. This system allows VEGF gene expression to be manipulated in vivo by providing tetracycline in the drinking water. In an allograft study, the ACE inhibitor, perindopril (PE) significantly attenuated VEGF-mediated tumor development accompanying the suppression of neovascularization in the tumor at a clinically comparable low dose. In vitro study showed that perindoprilat, which is an active form of PE, inhibited VEGF-induced endothelial cell migration. These results suggested that RAS played an important role in VEGF-mediated tumor development and angiogenesis.

Synergistic effect of basic fibroblast growth factor and vascular endothelial growth factor in murine hepatocellular carcinoma.

The growth of any solid tumor depends on angiogenesis. Among the known angiogenic factors, basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF), are potent and representative factors involved in tumor development. It has been reported that bFGF and VEGF showed a synergistic effect in both in vitro and in vivo angiogenesis. However, the interaction of these factors on tumor development and angiogenesis, including hepatocellular carcinoma (HCC), has not yet been elucidated. In this study, we examined the combined effect of bFGF and VEGF overexpression by means of a combination of a retroviral tetracycline (tet)-regulated (Retro-Tet) gene expression system, which can manipulate the gene expression in vivo by providing tet in the drinking water, and a conventional plasmid gene expression system. In an allograft study, bFGF and VEGF overexpression synergistically increased tumor growth and angiogenesis in the murine HCC cells. This synergistic effect also was found in established tumors. VEGF messenger RNA (mRNA) expression in the tumor was increased 3.1-fold by bFGF-overexpression, and the bFGF-induced tumor development was significantly attenuated by treatment with KDR/Flk-1 neutralizing monoclonal antibody. In conclusion, these results suggest that bFGF synergistically augments VEGF-mediated HCC development and angiogenesis at least partly by induction of VEGF through KDR/Flk-1.