Hepatocyte growth factor gene therapy of liver cirrhosis in rats

In vivo hepatocyte growth factor gene transfer to bladder smooth muscle after bladder outlet obstruction in the rat: a morphometric analysis

PURPOSE

We determined whether hepatocyte growth factor gene transfer after partial bladder outlet obstruction would prove effective for decreasing transforming growth factor-beta expression and consequently decreasing collagen deposition in partially obstructed rat bladders.

MATERIALS AND METHODS

Ten-week-old male Sprague-Dawley rats were divided into 3 groups of 10 each, including group 1--sham operation, group 2--bladder outlet obstruction for 4 weeks and group 3--hepatocyte growth factor gene transfer after bladder outlet obstruction. Two weeks after the onset of bladder outlet obstruction in group 3 hepatocyte growth factor-liposome complex (50 microg human hepatocyte growth factor cDNA) was injected into the smooth muscle of the rats.

RESULTS

We noted no difference between groups 2 and 3 with regard to the ratio of bladder weight to body weight. The ratio in groups 2 and 3 was significantly higher than in group 1 (p = 0.043). The mean percent of collagen area +/- SE was 36.32% +/- 1.83%, 27.90% +/- 2.66% and 8.97% +/- 3.35% in groups 1 to 3, respectively (p <0.05). Relative hepatocyte growth factor and c-met mRNA and protein expression were higher in group 3 than in groups 1 and 2. However, the expression of transforming growth factor-beta1 mRNA and protein was higher in group 2 than in groups 1 and 3.

CONCLUSIONS

These findings may imply a possible novel therapeutic strategy against bladder dysfunction arising in patients with bladder outlet obstruction.

Transforming growth factor beta-1 signalling in canine hepatic diseases: new models for human fibrotic liver pathologies

BACKGROUND/AIMS

The purpose of this study was to validate spontaneous chronic hepatitis and cirrhosis in dogs as a potential large animal model for fibrotic liver disease in humans by evaluating their molecular pathophysiology.

METHODS

Transforming growth factor-beta1 (TGF-beta1) signalling was analysed in liver samples of dogs with acute hepatitis (AH), chronic hepatitis (CH), cirrhosis (CIRR), and a specific form of cirrhosis, lobular dissecting hepatitis (LDH), in comparison with human cirrhotic samples from alcohol abuse (ALC) and hepatitis C (HC).

RESULTS

Canine samples were investigated with quantitative real-time PCR (Q-PCR) and Western blotting on TGF-beta1 signalling including Smad2/3 phosphorylation. Immunohistochemistry on collagens I and III was performed. Q-PCR showed an increase in TGF-beta1 levels and downstream effector gene products in CH, LDH, and CIRR. The same fibrotic diseases also showed an increase in phosphorylated Smad2/3 and a higher deposition of collagens I and III. In contrast, in AH neither active TGF-beta1 signalling nor collagen deposition was observed. Western blot analysis on human ALC and HC indicated a high similarity with canine samples in TGF-beta1 expression and Smad2/3 phosphorylation.

CONCLUSIONS

Our results demonstrate that fibrosis in spontaneous dog liver diseases is highly comparable to their human counterparts and might serve as models for anti-fibrotic strategies.

Reversal of fibrosis: no longer a pipe dream?

The reversal of liver fibrosis is not a new phenomenon. Treatment of the primary disease remains the most effective strategy, but new approaches to promote resolution of fibrosis are being built on the foundations that were provided by research into the basic mechanisms of fibrogenesis. A return to normal hepatic architecture from advanced fibrosis is achievable in some cases, and cirrhosis itself may be partly remediable.

Hepatic fibrosis, stellate cells, and portal hypertension

Hepatic fibrogenesis is the common result of injury to the liver. It is believed to be a critical factor that leads to hepatic dysfunction and may be important in portal hypertension. The fibrogenic response is a complex process in which accumulation of extracellular matrix proteins, tissue contraction, and alteration in blood flow are prominent. A critical event in fibrogenesis is activation of resident perisinusoidal cells that are termed "hepatic stellate cells". Stellate cell activation is characterized by many important phenotypes, including enhanced extracellular matrix synthesis and prominent contractility. Given the central role of stellate cell activation in hepatic fibrogenesis (and portal hypertension), effective therapy for hepatic fibrogenesis is most likely will be directed at this event.

Combination gene therapy of HGF and truncated type II TGF-beta receptor for rat liver cirrhosis after partial hepatectomy

BACKGROUND

In a cirrhotic liver, the regenerative ability and specific functions are impaired; a hepatic resection increases the possibility of postoperative liver failure. Hepatocyte growth factor (HGF) stimulates liver regeneration, accelerates restoration of hepatic function, and improves fibrosis. A truncated type II transforming growth factor-beta receptor (TbetaTR), which specifically inhibits TGF-beta signaling as a dominant-negative receptor, appears to prevent the progression of liver fibrosis. We demonstrated the therapeutic efficacy of adenovirus-mediated HGF and TbetaTR gene transduction after partial hepatectomy for liver cirrhosis.

METHODS

Rats were treated with dimethylnitrosamine for 3 weeks, and they all had severe cirrhosis. After partial hepatectomy (10%), we injected adenovirus expressing bacterial beta-galactosidase (AdLacZ), adenovirus expressing a truncated type II TGF-beta receptor (AdTbetaTR), adenovirus expressing hepatocyte growth factor (AdHGF), or AdTbetaTR + AdHGF into the portal vein, which was followed by an additional 2-week dimethylnitrosamine treatment.

RESULTS

On histologic examination, fibrotic tissue had decreased in the livers of the AdTbetaTR + AdHGF-treated rats compared with rats that were treated by AdLacZ, AdTbetaTR alone, and AdHGF alone. Liver function, which included serum levels of alanine aminotransferase, improved significantly in AdTbetaTR + AdHGF-treated rats compared with all other groups. The number of hepatocytes that were positive for proliferating-cell nuclear antigen was greater (P < .05) in AdHGF alone and AdTbetaTR + AdHGF-treated rat livers than in AdLacZ- and AdTbetaTR-treated rats. All AdTbetaTR + AdHGF-treated rats survived >60 days, and AdTbetaTR + AdHGF treatment markedly improved the survival rate after a partial hepatectomy.

CONCLUSION

Our results suggest that the combination of HGF and TbetaTR gene therapy may increase the possibility of hepatectomy in a cirrhotic liver by improving fibrosis, hepatic function, and hepatocyte regeneration.

Defect of Pro-Hepatocyte Growth Factor Activation by Fibroblasts in Idiopathic Pulmonary Fibrosis

RATIONALE AND OBJECTIVES

Hepatocyte growth factor (HGF) protects against lung fibrosis in several animal models. Pro-HGF activation to HGF is subjected to regulation by its activator (HGFA), a serine protease, and HGFA-specific inhibitors (HAI-1 and HAI-2). Our hypothesis was that fibroblasts from patients with idiopathic pulmonary fibrosis (IPF) had an altered capacity to activate pro-HGF in vitro compared with control fibroblasts.

METHODS

We measured the kinetics of pro-HGF activation in human lung fibroblasts from control subjects and from patients with IPF by Western blot. HGFA, HAI-1, and HAI-2 expression was evaluated by immunohistochemistry, RNA protection assay, and Western blot. We evaluated the effect of TGF-beta(1) and PGE(2) on pro-HGF activation and HGFA, HAI-1, and HAI-2 expression.

MAIN RESULTS

Lung fibroblasts activated pro-HGF in vitro. Pro-HGF activation was inhibited by serine protease inhibitors, by an anti-HGFA antibody, as well as by HAI-1 and HAI-2. Pro-HGF activation by IPF fibroblasts was reduced compared with control fibroblasts. In IPF fibroblasts, HGFA expression was lower and HAI-1 and HAI-2 expression was higher compared with control fibroblasts. PGE(2) stimulated pro-HGF activation through increased expression of HGFA and decreased expression of its inhibitor HAI-2. In contrast, TGF-beta(1) reduced the ability of lung fibroblasts to activate pro-HGF through decreased expression of HGFA and increased expression of its inhibitors.

CONCLUSIONS

IPF fibroblasts have a low capacity to activate pro-HGF in vitro via a low level of HGFA expression and high levels of HAI-1 and HAI-2 expression, and PGE(2) is able to partially correct this defect.

Angiogenic cell therapy for hepatic fibrosis

Progression of liver fibrosis has been linked with injuries associated with hypoxia and neovascularization. Neovascularization consists of angiogenesis and vasculogenesis, representing formation of blood vessels by differentiation of endothelial progenitor cells (EPCs). We investigated antifibrogenic and regenerative effects of EPC transplantation in chronic liver injury. Rat EPCs were isolated from bone marrow cells and examined in vitro for lineage markers. Recipient rats were injected intraperitoneally with dimethylnitrosamine (DMN) three times weekly for 4 weeks, plus EPC transplantation once weekly for 4 weeks. Transplanted rats showed suppression of liver fibrogenesis. Expression of growth factors promoting liver regeneration such as hepatocyte growth factor (HGF), transforming growth factor (TGF)-alpha, epidermal growth factor (EGF), and vascular endothelial growth factor (VEGF) was increased in transplanted rats, together with hepatocyte proliferation. Normal liver function parameters such as transaminase, total bilirubin, total protein, and albumin were maintained in transplanted rats. EPC transplantation is effective not only for preventing liver fibrosis but also for promoting regeneration in chronically damaged livers. Also, recently it has been reported that green fluorescent protein-positive bone marrow cells contribute to the liver tissue repair of fibrosis model rats. EPC transplantation might become an alternative if further preclinical investigation finds it to be effective in severely cirrhotic livers.

Met-regulated expression signature defines a subset of human hepatocellular carcinomas with poor prognosis and aggressive phenotype

Identification of specific gene expression signatures characteristic of oncogenic pathways is an important step toward molecular classification of human malignancies. Aberrant activation of the Met signaling pathway is frequently associated with tumor progression and metastasis. In this study, we defined the Met-dependent gene expression signature using global gene expression profiling of WT and Met-deficient primary mouse hepatocytes. Newly identified transcriptional targets of the Met pathway included genes involved in the regulation of oxidative stress responses as well as cell motility, cytoskeletal organization, and angiogenesis. To assess the importance of a Met-regulated gene expression signature, a comparative functional genomic approach was applied to 242 human hepatocellular carcinomas (HCCs) and 7 metastatic liver lesions. Cluster analysis revealed that a subset of human HCCs and all liver metastases shared the Met-induced expression signature. Furthermore, the presence of the Met signature showed significant correlation with increased vascular invasion rate and microvessel density as well as with decreased mean survival time of HCC patients. We conclude that the genetically defined gene expression signatures in combination with comparative functional genomics constitute an attractive paradigm for defining both the function of oncogenic pathways and the clinically relevant subgroups of human cancers.

In vivo hepatic HB-EGF gene transduction inhibits Fas-induced liver injury and induces liver regeneration in mice: a comparative study to HGF

BACKGROUND/AIMS

It is unknown whether heparin-binding EGF-like growth factor (HB-EGF) can be a therapeutic agent, although previous studies suggested that HB-EGF might be a hepatotrophic factor. This study explores the potential of hepatic HB-EGF gene therapy in comparison with HGF.

METHODS

Mice received an intraperitoneal injection of the agonistic anti-Fas antibody 72 h after an intravenous injection of either adenoviral vector (1x10(11) particles) expressing human HB-EGF (Ad.HB-EGF), human HGF (Ad.HGF) or no gene (Ad.dE1.3), and were sacrificed 24 or 36 h later to assess liver injury and regeneration.

RESULTS

Exogenous HB-EGF was predominantly localized on the membrane, suggesting the initial synthesis of proHB-EGF in hepatocytes. The control Ad.dE1.3-treated mice represented remarkable increases in serum ALT and AST levels and histopathologically severe liver injuries with numerous apoptosis, but a limited number of mitogenic hepatocytes. In contrast, the liver injuries and apoptotic changes were significantly inhibited, but the mitogenic hepatocytes remarkably increased, in both the Ad.HB-EGF- and Ad.HGF-treated mice. More mitogenic hepatocytes and milder injuries were observed in the Ad.HB-EGF-treated mice.

CONCLUSIONS

HB-EGF has more potent protective and mitogenic effects for hepatocytes than HGF, at least for the present conditions. In vivo hepatic HB-EGF gene transduction is therapeutic for Fas-induced liver injury.

HGF gene therapy attenuates renal allograft scarring by preventing the profibrotic inflammatory-induced mechanisms

Inflammatory processes and tissue scarring are characteristic features of chronic allograft nephropathy. Hepatocyte growth factor (HGF) has beneficial effects on renal fibrosis and it also ameliorates renal interstitial inflammation as it has been recently described. Contrarily to protein administration, intramuscular gene electrotransfer allows sustained release of HGF. So, here we hypothesized that gene therapy with human HGF would diminish the characteristic scarring of chronic allograft nephropathy either by antagonizing tissue fibrosis mechanisms or by reducing inflammation. Lewis rats transplanted with cold preserved Fischer kidneys received vehicle (NoHGF) or intramuscular plasmid DNA encoding HGF plus electroporation either before transplantation (IniHGF, early post-transplant cytoprotection of tubular cells) or 8/10 weeks after transplantation (DelHGF, delayed prevention of chronic mechanisms). Serum creatinine and proteinuria were measured every 4 weeks for 24 weeks. Grafts at 12 or 24 weeks were evaluated for glomerulosclerosis, fibrosis inflammatory cells and mediators, cell regeneration and tubulo-interstitial damage. Nontreated animals developed renal insufficiency, progressive proteinuria and fibrosis among other characteristic histological features of chronic allograft nephropathy. Treatment with human HGF, especially when delayed until the onset of fibrogenic mechanisms, reduced renal failure and mortality, diminished tubule-interstitial damage, induced cell regeneration, decreased inflammation, NF-kappaB activation, and profibrotic markers at 12 weeks and prevented late interstitial fibrosis and glomerulosclerosis. The effectiveness of HGF-gene therapy in the prevention of renal allograft scarring is related with the halt of profibrotic inflammatory-induced mechanisms.

Hepatocyte growth factor gene transfer to alveolar septa for effective suppression of lung fibrosis

We examined therapeutic gene transfer of human hepatocyte growth factor (hHGF) to alveolar septa in mouse bleomycin-induced lung fibrosis using macroaggregated albumin-polyethylenimine complex (MAA-PEI). Intravenous administration of MAA-PEI along with 1 microg pCAG.hHGF to C57BL/6 mice increased the uptake of plasmids into alveolar capillary endothelial cells and epithelial cells, prolonged hHGF expression in the lung, and induced a level of hHGF expression equal to that seen with 10 microg of hHGF-expression plasmids alone. The exogenous source of hHGF gene expression increased the endogenous mouse HGF in the lungs and significantly decreased TNF-alpha, IL-6, and collagen synthesis after bleomycin injury. Because GFP-labeled bone marrow-derived stem cells after bleomycin injury were reduced in number by HGF, the primary mechanism of HGF is likely to be the prevention of apoptosis, as has been suggested by in vitro experiments. This novel HGF gene transfer method to alveolar septa with nonstimulatory MAA-PEI conjugates may have promising clinical applications.

Tumor necrosis factor-a antisense transfer remarkably improves hepatic graft viability

BACKGROUND

Cold ischemia/reperfusion injury of the hepatic graft, an unsolved problem in liver transplantations, is attributed to the release of inflammatory cytokines, especially the tumor necrosis factor- (TNF) alpha, from activated Kupffer cells (KC). Therefore, the specific inhibition of TNF-alpha could improve the viability of the hepatic graft upon reperfusion.

METHODS

We assessed the efficacy of TNF-alpha antisense (TNF-AS) oligodeoxynucleotides (ODNs) delivery to KC in a rodent liver transplantation model.

RESULTS

Seventy-one percent of the animals that received 6 hours preserved grafts in baths of lactated Ringer's solution (4 degrees C) and were treated with TNF-AS survived for over 14 days. Eighty percent of the animals treated with vehicle, sense ODNs, or balanced salt saline (BSS) died. Four hours after reperfusion of the liver, a significant reduction was noted in livers treated with TNF-AS in the release of cytosolic enzymes from the hepatocytes and the serum TNF-alpha (P<0.05). The expressions of TNF-alpha on KC and of intercellular adhesion molecule-1 on sinusoidal endothelial cells were completely suppressed in TNF-AS-treated livers.

CONCLUSIONS

TNF-AS delivery improves the viability of the hepatic graft, and this technique may solve hepatic graft nonfunction in a clinical setting.

Hepatocyte growth factor attenuates liver fibrosis induced by bile duct ligation

Hepatic fibrosis is a common outcome of a variety of chronic liver diseases. Here we evaluated the therapeutic efficacy of hepatocyte growth factor (HGF) on liver fibrosis induced by bile duct ligation (BDL) and investigated potential mechanisms. Mice underwent BDL, followed by intravenous injections of naked HGF expression plasmid or control vector. HGF gene therapy markedly ameliorated hepatic fibrotic lesions, as demonstrated by reduced alpha-smooth muscle actin (alphaSMA) expression, attenuated deposition of type I and type III collagen, and normalized total hydroxyproline content. HGF also suppressed transforming growth factor-beta1 (TGF-beta1) expression. Interestingly, colocalization of alphaSMA and cytokeratin-19 in bile duct epithelium was observed, suggesting the possibility of biliary epithelial to myofibroblast transition after BDL. Cells that were still positive for cytokeratin-19 but actively producing type I collagen were found in the biliary epithelia and periductal region. Laminin staining revealed an impaired basement membrane of the bile duct epithelium in diseased liver. These lesions were largely prevented by HGF administration. In vitro, treatment of human biliary epithelial cells with TGF-beta1 induced alphaSMA and fibronectin expression and suppressed cytokeratin-19. HGF abolished the phenotypic conversion of biliary epithelial cells induced by TGF-beta1. These results suggest that HGF ameliorates hepatic biliary fibrosis in part by blocking bile duct epithelial to mesenchymal transition.

Angiogenic and antifibrotic actions of hepatocyte growth factor improve cardiac dysfunction in porcine ischemic cardiomyopathy

Impairment of cardiac function in ischemic cardiomyopathy has been postulated to be due to the decrease in blood flow and increase in collagen synthesis. Therefore, an approach to alter them directly by means of a growth factor may open up a new therapeutic concept in ischemic cardiomyopathy. From this viewpoint, hepatocyte growth factor (HGF) is a unique growth factor with angiogenic and antifibrotic effects. Thus, we examined the feasibility of gene therapy using HGF plasmid DNA for ischemic cardiomyopathy. Human HGF plasmid DNA at a dose of 0.4 or 4 mg was injected into ischemic myocardium of pigs induced by ameroid constrictor with the NOGA system. At 1 month after injection, the ischemic area was significantly reduced in the HGF group, accompanied by a significant increase in capillary density and regional myocardial perfusion in the ischemic area (P<0.01). In contrast, a significant decrease in fibrotic area was observed in the HGF group, associated with a significant decrease in collagen I, III and TGF-beta synthesis as compared to the control group (P<0.01). Consistently, cardiac function was significantly improved in the 4 mg HGF group as compared to the control group (P<0.05). Overall, the present in vivo experiments demonstrated that intramyocardial injection of human HGF plasmid DNA in ischemic cardiomyopathy resulted in a significant improvement in cardiac function through an increase in blood flow and decrease in fibrosis. These favorable outcomes suggest potential utility to treat patients with ischemic heart disease using HGF gene transfer. Currently, a phase I study using human HGF plasmid DNA is ongoing to test the validity of this concept.

Mammalian Target of Rapamycin Pathway Blockade Slows Progression of Diabetic Kidney Disease in Rats

Recent data suggest that the phosphatidylinositol 3-kinase (PI3-K)/Akt/mammalian target of rapamycin (mTOR) pathway is important in diabetic nephropathy. The effect of mTOR blockade by sirolimus (SRL) in diabetic kidney disease in rats was investigated. Diabetes was induced by streptozotocin in male Sprague-Dawley rats. Sixteen weeks later, diabetic animals were divided into the following groups: diabetes (D; n = 8), diabetes + SRL at 1 mg/kg per d, SRL trough level 2.3 +/- 0.25 ng/ml (D+SRL; n = 7); and diabetes + normoglycemia maintained by insulin implants (D+NG; n = 5). There was an age-matched nondiabetic group (ND; n = 6). All animals were followed for 4 wk. The D group showed glomerular hypertrophy (mean glomerular volume 5.0 +/- 0.4 in D versus 3.3 +/- 0.2 10(6) mu(3) in ND; P < 0.05) without renal hyperplasia (calculated by reverse transcription-PCR of proliferative cell nuclear antigen) and albuminuria (29 +/- 4 in D versus 1.4 +/- 1.5 mg/24 h in ND; P < 0.05). Both D+NG and D+SRL groups had a significant reduction of albuminuria, although glomerular hypertrophy was still present. SRL treatment did not modify the number of infiltrating renal ED1(+) cells. Diabetic animals had greater expression of p-Akt and mTOR, unlike ND rats. NG and SRL treatment reduced p-Akt and normalized mTOR. It is interesting that D+SRL was associated with a significant reduction of renal TGF-beta1 and glomerular connective tissue growth factor. SRL treatment reduced glomerular alpha-smooth muscle actin overexpression and reduced significantly the mesangial matrix accumulation that is characteristic of diabetic nephropathy. In conclusion, mTOR blockade by low-dose SRL has a beneficial effect in diabetic kidney disease, suggesting that the mTOR pathway has an important pathogenic role in diabetic nephropathy.

Mechanisms of alcohol-induced hepatic fibrosis: a summary of the Ron Thurman Symposium

This report is a summary of Ron Thurman Symposium on the Mechanisms of Alcohol-Induced Hepatic Fibrosis which was organized by The National Institutes of Health in Santa Barbara, California, June 25, 2005. The Symposium and this report highlight the unique aspects by which drinking alcoholic beverages may result in hepatic fibrosis. Acetaldehyde, the first metabolite of ethanol, can upregulate transcription of collagen I directly as well as indirectly by upregulating the synthesis of transforming growth factor-beta 1 (TGF-beta1). Reactive oxygen species (ROS) generated in hepatocytes by alcohol metabolism can activate collagen production in hepatic stellate cells (HSCs) in a paracrine manner. Alcohol-induced hepatocyte apoptotic bodies can be phagocytosed by HSCs and Kupffer cells and result in increased expression of TGF-beta1 and subsequent HSC activation. Kupffer cells may contribute to the activation of HSCs by releasing ROS and TGF- beta1. Innate immunity may suppress hepatic fibrosis by killing activated HSCs and blocking TGF-beta1 signaling. In patients infected with hepatitis C virus (HCV), alcohol may promote hepatic fibrosis by suppressing innate immunity. HCV core and non-structural proteins contribute to HCV-induced hepatic fibrosis. Alcohol and HCV together may promote hepatic fibrosis through increased oxidative stress and upregulation of fibrogenic cytokines. The inactive aldehyde dehydrogenase (ALDH2) and the super-active alcohol dehydrogenase (ADH2) alleles may promote hepatic fibrosis through increased accumulation of acetaldehyde in the liver. Hepatic fibrosis can be reversed by inducing selective apoptosis or necrosis of activated HSCs, or by reverse trans-differentiation of activated HSCs into the quiescent phenotype.

Diagnostic accuracy of serum biochemical fibrosis markers in children with chronic hepatitis B evaluated by receiver operating characteristics analysis

AIM

To investigate the diagnostic accuracy of potent serum biochemical fibrosis markers in children with chronic hepatitis B evaluated by receiver operating characteristics (ROC) analysis.

METHODS

We determined the serum level of apolipoprotein A-I (APO A-I), haptoglobin (HPT) and a-2 macroglobulin (A2M) with an automatic nephelometer in 63 children (age range 4-17 years, mean 10 years) with biopsy-verified chronic HBeAg-positive hepatitis B. Fibrosis stage and inflammation grade were assessed in a blinded fashion according to Batts and Ludwig. We defined mild liver fibrosis as a score < or =2 and advanced fibrosis as a score equal to 3. ROC analysis was used to calculate the power of the assays to detect advanced liver fibrosis (AccuROC, Canada).

RESULTS

Serum concentrations of APO A-I, HPT and A2M were not significantly different in patients with chronic hepatitis B compared to controls. However, APO A-I level of 1.19 ng/L had a sensitivity of 85.7% and a specificity of 60.7% (AUC = 0.7117, P = 0.035) to predict advanced fibrosis. All other serum biochemical markers and their combination did not allow a useful prediction. None of these markers was a good predictor of histologic inflammation.

CONCLUSION

Apolipoprotein A-I may be a suitable serum marker to predict advanced liver fibrosis in children with chronic hepatitis B.

Hepatocyte Growth Factor Gene Therapy Slows Down the Progression of Diabetic Nephropathy in db/db Mice

BACKGROUND

Effect of hepatocyte growth factor (HGF) has scarcely been determined on diabetic nephropathy.

METHODS

Adenovirus encoding human HGF gene or LacZ gene (as the control) was injected into the hindlimb muscles of the C57BL/KsJ-db/db (db/db) mice at the age of 12 weeks, a model of genetic diabetes. Diabetic nephropathy was then evaluated at the age of 24 weeks.

RESULTS

The urine volume and albumin excretion progressively decreased in the control, whereas they remained unchanged in the HGF-treated group during the 12-week follow-up. The HGF gene therapy did not affect glucose metabolism. However, it resulted in a better renal function as evaluated by creatinine clearance (Ccr) than the control; Ccr was progressively worsened in controls (0.14 +/- 0.02 liters/day) whereas unchanged in the HGF gene-treated group (0.38 +/- 0.09 liters/day, p < 0.05). Kidneys of the HGF gene-treated mice showed glomeruli with greater area and cell population, smaller glomerular sclerotic index, and less fibrosis in both glomeruli and renal tubules, where apoptotic rate of glomerular endothelial cells and that of tubular epithelial cells were significantly decreased. TGF-beta1 expression was significantly decreased in kidneys of the HGF gene-treated group. Finally, the HGF treatment significantly improved the long-term survival of db/db mice.

CONCLUSIONS

The HGF gene delivery thus appeared to slow down the aggravation of diabetic nephropathy in db/db mice by attenuating progression from the hyperfiltration phase into the sclerotic phase through antiapoptotic and antifibrotic actions. The present findings suggest that the HGF gene delivery can be a novel therapeutic approach against diabetic nephropathy.

Modulation of hepatocyte growth factor plasma levels in relation to the dose of exogenous heparin administered: an experimental study in rats

INTRODUCTION

Partial liver transplantation has been consolidated to be a valid treatment option. We sought to understand the factors that modulate and may be harnessed to accelerate hepatocyte regeneration. We sought to determine the impact of heparin on m-hepatocyte growth factor (HGF) plasma concentrations.

MATERIALS AND METHODS

Sixteen rats were assigned to four groups of four animals each: group A, without heparin; group B, 600 IU/kg; group C, 1000 IU/kg, group D, 1400 IU/kg. Blood samples (0.5 mL) were obtained from each rat at baseline and at 30, 60, 120, and 240 minutes. After the samples were centrifuged to separate supernates from the cell phase they were stored at -20 degrees C in the m-HGF reagent and subsequently tested using enzyme-linked immunosorbent assay. Results were analyzed using SPSS 11.5 statistical software.

RESULTS

Among the 16 rats, one died at 110 minutes, just prior to the last extraction. The remaining rats were sacrificed. Mean weight was: 466 +/- 64.24 g with no intergroup differences (P = .149). The comparative results (using Student t test) were: baseline A(1-4) versus A(1-4) 30 minutes: P < .05; baseline A(1-4) versus A(1-4) 60 minutes: P < .05; baseline A(1-4) versus A(1-4) 120 minutes: P = .10 (NS); baseline A(1-4) versus A(1-4) 240 minutes: P = .15 (NS). No significant differences were found among group B: baseline C(1-4) versus C(1-4) 30 minutes and 60 minutes: NS; baseline C(1-4) versus C(1-4) 120 minutes: P < .001; baseline C(1-4) versus C(1-4) 240 minutes: P < .10 (NS). Finally, the results in group D were: baseline D(1-4) versus D(1-4) 30 minutes: NS; baseline D(1-4) versus D(1-4) 60 minutes and 120 minutes: P < .05; baseline D(1-4) versus D(1-4) 240 minutes: P < .0005. When we compared group A to C and D, we detected differences (albeit not when compared to B) with P values = .01. Peak values were obtained at 120 and 240 minutes (225.21 pg/mL and 221.78 pg/mL) among groups C and D.

CONCLUSION

Heparin has a positive effect to increase serum HGF concentrations among rats. The effect was dependent on the administered dose and the time elapsed.

Critical role of plasminogen activator inhibitor-1 in cholestatic liver injury and fibrosis

Plasminogen activator inhibitor-1 (PAI-1) is an acute phase protein known to correlate with hepatic fibrosis. However, whether or not PAI-1 plays a causal role in this disease process had not been directly tested. Therefore, wild-type or PAI-1 knockout (PAI-1(-/-)) mice underwent bile duct ligation. Mice were sacrificed either 3 or 14 days after surgery for assessment of early (i.e., inflammation) and late (i.e., fibrosis) changes caused by bile duct ligation. Liver injury was determined by histopathology and plasma enzymes. Accumulation of extracellular matrix was evaluated by Sirius red staining and by measuring hydroxyproline content. Hepatic expression of PAI-1 was increased approximately 9-fold by bile duct ligation in wild-type mice. Furthermore, early liver injury and inflammation due to bile duct ligation was significantly blunted in PAI-1(-/-) mice in comparison with wild-type mice. Although PAI-1(-/-) mice were significantly protected against the accumulation of extracellular matrix caused by bile duct ligation, increases in expression of indices of stellate cell activation and collagen synthesis caused by bile duct ligation were not attenuated. Protection did, however, correlate with an elevation in hepatic activities of plasminogen activator and matrix metalloprotease activities. In contrast, the increase in tissue inhibitor of metalloproteases-1 protein, a major inhibitor of matrix metalloproteases, caused by bile duct ligation was not altered in PAI-1(-/-) mice compared with the wild-type strain. The increase in hepatic activity of urokinase-type plasminogen activator was also accompanied by more activation of the hepatocyte growth factor receptor c-Met. Taken together, these data suggest that PAI-1 plays a causal role in mediating fibrosis during cholestasis.

Anti-TGF-beta strategies for the treatment of chronic liver disease

Permanent alcohol abuse may lead to chronic liver injury with deleterious sequelae such as liver cirrhosis and hepatocellular carcinoma. Mechanisms of fibrogenesis encompass recruitment of inflammatory cells at the site of injury and cytokine mediated activation of hepatic stellate cells (HSC) with accumulation of interstitial collagens. HSC transdifferentiation and accompanying apoptosis result in destruction of liver architecture and are therefore key steps of disease progression. TGF-beta represents the main profibrogenic cytokine in liver fibrosis and other fibroproliferative disorders by inducing extracellular matrix deposition as part of the wound healing response. In parallel, TGF-beta triggers hepatocytes that are strongly responsive for this cytokine, to undergo apoptosis, thereby providing space for HSC proliferation and generation of a collagenous matrix. Anti TGF-beta approaches were established and successfully utilized for the treatment of experimental fibrogenesis. Dominant negative TGF-beta receptors (TbetaR), generated by fusing the Fc domain of human IgG and the N-terminal (extracellular) fragment of TbetaRII (Fc:TbetaRII) were applied to suppress fibrosis. Similarly TGF-beta binding proteins like decorin, antagonistic cytokines such as bone morphogenetic protein-7, hepatocyte growth factor, IL-10, or IFN-gamma were as efficient as camostat mesilate, a protease inhibitor that possibly abrogated proteolytic activation of TGF-beta. Further, our group recently overexpressed Smad7 in bile duct ligation induced liver fibrosis and achieved efficient inhibition of intracellular TGF-beta signaling, thereby counteracting profibrogenic effects in cultured HSC and in vivo. A direct link between the effect of alcohol and TGF-beta exists through reactive oxygen species that are generated in liver cells by alcohol metabolism and represent activators of TGF-beta signaling. Thus, soluble TbetaRII expression reduced experimental fibrogenesis in vitro and in vivo partially by decreasing intracellular ROS and inhibiting NADH oxidase. Approaches that specifically target profibrogenic TGF-beta signaling are promising to treat alcoholic liver disease in the future. However, to ensure safety for the patients to be treated, approaches with strong specificity need to be established. Therefore, it is essential to delineate the profibrogenic actions of TGF-beta and the influence of alcohol abuse in molecular detail.

Attenuation of mouse acute colitis by naked hepatocyte growth factor gene transfer into the liver

BACKGROUND

Hepatocyte growth factor (HGF) has multiple biological effects on a wide variety of cells. It modulates intestinal epithelial proliferation and migration, and critically regulates intestinal wound healing.

AIMS

To investigate the therapeutic effect of HGF gene transfer, we introduced the HGF gene into the liver of mice with acute colitis.

METHODS

The rat HGF expression plasmid vector, pCAGGS-HGF, was injected via the tail vein into C57BL/6 mice, followed by dosing with dextran sulfate sodium in distilled water. Firstly, the HGF gene was injected once on day 0. Secondly, the HGF gene was injected on day 0 and again on day 2.

RESULTS

Injection of the HGF gene ameliorated colitis with inhibition of both loss of body weight and shortening of colon length. It protected the colon from epithelial erosions and cellular infiltration. Expression of mRNAs for IFN-gamma, IL18, and TNF-alpha was reduced in the colon. In contrast, expression of mRNA for IL-10 was increased. The numbers of BrdU-positive intestinal epithelial cells were increased, and the numbers of TUNEL-positive apoptotic cells were decreased. Furthermore, a second injection prolonged the elevation of serum HGF levels, and ameliorated the symptoms better than a single injection. The empty pCAGGS plasmid did not ameliorate acute colitis.

CONCLUSIONS

HGF gene transfer attenuated acute colitis by facilitating intestinal wound repair as well as inhibiting inflammation, suggesting a new strategy for treatment of IBD.

Emerging therapies for liver fibrosis

Liver fibrosis occurs as a result of a wide range of injurious processes and in its end-stage results in cirrhosis. This gross disruption of liver architecture is associated with impaired hepatic function, portal hypertension and significant resultant morbidity and mortality. Indeed, liver fibrosis and cirrhosis represent a major worldwide healthcare burden. Recent progress in liver transplantation, the management of portal hypertension and the treatment of chronic viral hepatitis have had an important impact. However, these approaches are not without their limitations - in particular, issues regarding organ availability for transplantation - and serve to highlight the urgent requirement to influence pharmacologically the underlying fibrotic process in many patients. Liver fibrosis has been shown to be a bidirectional process and increasing data from laboratory and clinical studies reveal that even advanced fibrosis and cirrhosis are potentially reversible. Exploration of the molecular mechanisms underlying this bi-directionality will lead to char acterisation of the essential attributes of an antifibrotic therapy. In this review, these mechanisms are highlighted and the growing number of emerging antifibrotic agents discussed.

Antifibrotic agents for liver disease

Complications from chronic hepatitis C (HCV) and recurrent HCV post-transplant are responsible for significant morbidity and mortality in the United States and Europe. Current antiviral therapies are at best, effective in up to 50% of patients in the pre-transplant setting, and in the post-transplant setting are associated with more limited efficacy and increased toxicity. With this reduced efficacy of antiviral strategies in the post-transplant setting, new approaches are urgently needed. Substantial progress has been made in understanding the pathogenesis of hepatic fibrosis over the last 20 years, which has yielded potential new therapeutic targets. The prospect of antifibrotic therapies is nearing reality in order to reduce progression to cirrhosis, thereby reducing morbidity, mortality and the need for re-transplantation. Current and evolving approaches primarily target the activated hepatic stellate cells, which are the main source of extracellular matrix, along with related fibrogenic cell types. Key issues yet to be clarified include the optimal duration of antifibrotic therapies, endpoints of clinical trials, indications in clinical practice and whether combination therapies might yield synergistic activity.

Regenerative and fibrotic pathways in canine hepatic portosystemic shunt and portal vein hypoplasia, new models for clinical hepatocyte growth factor treatment

Background

We analyzed two spontaneous dog diseases characterized by subnormal portal perfusion and reduced liver growth: (i) congenital portosystemic shunts (CPSS) without fibrosis and (ii) primary portal vein hypoplasia (PPVH), a disease associated with fibrosis. These pathologies, that lack inflammation or cholestasis, may represent simplified models to study liver growth and fibrosis. To investigate the possible use of those models for hepatocyte growth factor (HGF) treatment, we studied the functionality of HGF signaling in CPSS and PPVH dogs and compared this to aged-matched healthy controls.

Results

We used quantitative real-time polymerase chain reaction (Q-PCR) to analyze the mRNA expression of HGF, transforming growth factor β1 (TGF-β1), and relevant mediators in liver biopsies from cases with CPSS or PPVH, in comparison with healthy control dogs. CPSS and PPVH were associated with a decrease in mRNA expression of HGF and of MET proto-oncogene (c-MET). Western blot analysis confirmed the Q-PCR results and showed that intracellular signaling components (protein kinase B/Akt, ERK1/2, and STAT3) were functional. The TGF-β1 mRNA levels were unchanged in CPSS whereas there was a 2-fold increase in PPVH indicating an active TGF-β1 pathway, consistent with the observation of fibrosis seen in PPVH. Western blots on TGF-β1 and phosphorylated Smad2 confirmed an activated pro-fibrotic pathway in PPVH. Furthermore, Q-PCR showed an increase in the amount of collagen I present in PPVH compared to CPSS and control, which was confirmed by Western blot analysis.

Conclusion

The pathophysiological differences between CPSS and PPVH can adequately be explained by the Q-PCR measurements and Western blots. Although c-MET levels were reduced, downstream signaling seemed to be functional and provides a rational for HGF-supplementation in controlled studies with CPSS and PPVH. Furthermore both diseases may serve as simplified models for comparison with more complex chronic inflammatory diseases and cirrhosis.

A novel role of hepatocyte growth factor as an immune regulator through suppressing dendritic cell function

Hepatocyte growth factor (HGF) plays an important role in many biological events such as angiogenesis, cell proliferation, anti-fibrosis and antiapoptosis. It is well known that HGF promotes tumor progression and suppresses development of fibrosis after tissue injury. In contrast, its role in immune-mediated disorders has not been fully clarified. In the present study, we examined the role of HGF in Ag-specific immune response using in vitro studies and an experimental model of allergic airway inflammation. We first confirmed that dendritic cells (DCs) expressed the receptor for HGF, c-met, which was not expressed in T cells. Treatment with HGF both in vitro and in vivo potently suppressed DC functions such as Ag-presenting capacity, thus down-regulating Ag-induced Th1- and Th2-type immune responses. Exogenous administration of the HGF expression plasmid into Ag-primed mice markedly suppressed the development of airway eosinophilia and airway hyperresponsiveness, which was induced by Ag inhalation, with suppression of the Ag-presenting capacity of DCs in the lung. HGF exhibited these immunosuppressive effects without up-regulation of IL-10 or TGF-beta. We also found that expression of endogenous HGF in the lung significantly increased following Ag sensitization and inhalation challenges. Finally, neutralization of endogenous HGF in vivo significantly increased airway eosinophilia and airway hyperresponsiveness with up-regulation of the Ag-presenting capacity of DCs in the lung. These results demonstrated a novel, significant, and possibly therapeutic role of HGF as a potent regulator in immune-mediated disorders such as asthma.

Gene transfection of hepatocyte growth factor attenuates the progression of cardiac remodeling in the hypertrophied heart

OBJECTIVES

Hepatocyte growth factor plays a significant role in angiogenesis, anti-apoptosis, and anti-transforming growth factor-beta1-mediated fibrosis in several organs. In this study, we investigated the effect of transfection of the hepatocyte growth factor gene in attenuation of cardiac remodeling in the hypertrophied heart.

METHODS

Two weeks after banding the ascending aorta of male Sprague-Dawley rats, a hemagglutinating virus of Japan-liposome complex with (H group) or without (C group) human hepatocyte growth factor cDNA was transfected into the left ventricle wall by direct injection. The hepatocyte growth factor, c-Met, and transforming growth factor-beta1 mRNA levels in the left ventricle were then analyzed by real-time quantitative reverse-transcriptase polymerase chain reaction.

RESULTS

Two weeks after transfection, the expression of transforming growth factor-beta1 mRNA was significantly attenuated in the H group compared with the C group (P < .01). Myocardial collagen content after 4 weeks of banding was significantly lower in the H group (5.0 +/- 0.6 mg/g tissue) than in the C group (7.4 +/- 0.5 mg/g tissue, P < .01). Left ventricular diastolic function (E/A ratios quantified by Doppler echocardiography) showed a significant increase in the H group (1.9 +/- 0.1) compared with the C group (1.1 +/- 0.1, P < .01).

CONCLUSIONS

Our results demonstrated that gene transfection of hepatocyte growth factor attenuated left ventricular diastolic dysfunction and cardiac fibrosis in association with a decrease in transforming growth factor-beta1 in the rat heart subjected to pressure overload. Thus, the transfection of the hepatocyte growth factor gene into the hypertrophied heart may be a strategy for the hypertrophied and failing heart even for cardiac surgery.

Transcriptional profiling after bile duct ligation identifies PAI-1 as a contributor to cholestatic injury in mice

Extrahepatic cholestasis leads to complex injury and repair processes that result in bile infarct formation, neutrophil infiltration, cholangiocyte and hepatocyte proliferation, extracellular matrix remodeling, and fibrosis. To identify early molecular mechanisms of injury and repair after bile duct obstruction, microarray analysis was performed on liver tissue 24 hours after bile duct ligation (BDL) or sham surgery. The most upregulated gene identified encodes plasminogen activator inhibitor 1 (PAI-1, Serpine 1), a protease inhibitor that blocks urokinase plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) activity. Because PAI-1, uPA, and tPA influence growth factor and cytokine processing as well as extracellular matrix remodeling, we evaluated the role of PAI-1 in cholestatic liver injury by comparing the injury and repair processes in wild-type (WT) and PAI-1-deficient (PAI-1-/-) mice after BDL. PAI-1-/- mice had fewer and smaller bile infarcts, less neutrophil infiltration, and higher levels of cholangiocyte and hepatocyte proliferation than WT animals after BDL. Furthermore, PAI-1-/- mice had higher levels of tPA activation and mature hepatocyte growth factor (HGF) after BDL than WT mice, suggesting that PAI-1 effects on HGF activation critically influence cholestatic liver injury. This was further supported by elevated levels of c-Met and Akt phosphorylation in PAI-1-/- mice after BDL. In conclusion, PAI-1 deficiency reduces liver injury after BDL in mice. These data suggest that inhibiting PAI-1 might attenuate liver injury in cholestatic liver diseases.

Hepatocyte growth factor contributes to fracture repair by upregulating the expression of BMP receptors

Hepatocyte growth factor (HGF) is activated and the expression of BMP receptors (BMPRs) is induced around the fracture site during the early phase of fracture repair. HGF facilitates the expression of BMPRs in mesenchymal cells. This study suggests that HGF contributes to fracture repair by inducing the expression of BMPRs.

INTRODUCTION

The precise mechanisms that control the upregulation of BMP, BMPRs, and other molecules involved in bone repair are not completely understood. In this study, we hypothesized that HGF, activated through the action of thrombin on the HGF activator, may enhance BMP action through the local induction of BMP or BMPRs.

MATERIALS AND METHODS

Callus samples from tibial fractures in mice were harvested for immunohistochemical analysis of HGF and phosphorylated c-Met, for in situ hybridization of BMPRs, and for real-time RT-PCR analysis for the expression of HGF, c-Met, and BMPRs. To study the changes in gene expression of BMPRs in response to HGF, C3H10T1/2 cells were cultured with or without HGF and harvested for real-time RT-PCR and for Western blot analysis. To evaluate the contribution of HGF to the biological action of BMP2, C3H10T1/2 cells and primary muscle-derived mesenchymal cells were precultured with HGF and cultured with BMP2. In addition, the expression of the luciferase gene linked to the Id1 promoter containing the BMP responsive element and alkaline phosphatase (ALP) activity were assayed.

RESULTS

Positive immunostaining of HGF and phosphorylated c-Met was detected around the fracture site at 1 day after the fracture was made. mRNA expression of BMPRs was increased 1 day after fracture and localized in mesenchymal cells at the fracture site. From an in vitro study, the expression of mRNA for BMPRs was elevated by treatment with HGF, but the expression of BMP4 did not change. Western blot analysis also showed the upregulation of BMPR2 by HGF treatment. The results from the luciferase and ALP assays indicated increased responsiveness to BMPs by treating with HGF.

CONCLUSIONS

This study indicates that HGF is activated and expressed at the fracture site and that HGF induces the upregulation of BMPRs in mesenchymal cells. Furthermore, HGF may facilitate BMP signaling without altering the expression of BMP molecules.

A review of hazardous chemical toxicity studies utilizing genetically-modified animals--their applications for risk assessment

Studies on the mechanisms of chemical toxicity carried out using knockout mice lacking genes of enzymes for drug metabolism or nuclear receptor proteins were reviewed, and the studies were compared with the respective conventional mechanistic studies. While the toxicity of many hazardous chemicals was observed only in wild-type or knockout mice, which clearly showed that their toxicity was involved in the enzyme or receptor, some chemicals exhibited the same degree of toxicity in two genotypes, i.e., in both the wild strain and knockout mice, demonstrating that the enzymes or receptors are not involved in their toxicity. The use of genetically-modified animals presents not only the advantage of simultaneous evaluation of toxicity endpoints and mechanisms, but also suggests significant benefits over conventional methods using several chemicals to elucidate toxicity mechanisms. Elucidation of the mechanism of toxicity will provide useful information for risk assessment, and the use of genetically-modified animals for this purpose will lead to the advancement of this assessment.

Nonviral HVJ (hemagglutinating virus of Japan) liposome-mediated retrograde gene transfer of human hepatocyte growth factor into rat nervous system promotes functional and histological recovery of the crushed nerve

Hepatocyte growth factor (HGF) is well known to be involved in many biological functions, such as organ regeneration and angiogenesis, and to exert neurotrophic effects on motor, sensory, and parasympathetic neurons. In this study, we gave repeated intramuscular injections of the human HGF gene, using nonviral HVJ (hemagglutinating virus of Japan) liposome method, to examine whether transfection of the rat nervous system with this gene is able to exert neurotrophic effects facilitating recovery of a crushed nerve. The expression of HGF protein and HGF mRNA indicated that gene transfer into the nervous system did occur via retrograde axonal transport. At 4 weeks after crush, electrophysiological examination of the crushed nerve showed a significantly shorter mean latency and a significantly greater mean maximum M-wave amplitude with repeated injections of HGF gene. Furthermore, histological findings showed that the mean diameter of the axons, the axon number and the axon population were significantly larger in the group with repeated injections of HGF gene. The above results show that repeated human HGF gene transfer into the rat nervous system is able to promote crushed-nerve recovery, both electrophysiologically and histologically, and suggest that HGF gene transfer has potential for the treatment of crushed nerve.

Usefulness of granular BCAA after hepatectomy for liver cancer complicated with liver cirrhosis

OBJECTIVE

Nutritional disturbances such as ascites and hypoalbuminemia frequently arise after hepatectomy for liver cancer with liver cirrhosis. We examined the possibility of maintaining a favorable state of nutrition by outpatient administration of branched-chain amino acid (BCAA) granules.

METHODS

Forty-three patients who had gross liver cirrhosis complicated by liver cancer and underwent surgery up to May 2002 were given BCAA granules (n = 21, BCAA group) or no granules (n = 22, control group).

RESULTS

1) Background details such as age, sex, surgical technique, blood loss, and duration of surgery showed no significant differences. 2) Among objective findings, improvement of ascites and edema tended to occur sooner in the BCAA group, but without a significant difference. 3) Although serum albumin recovered its preoperative value 9 mo after surgery in the control group, only 6 mo was required for recovery in the BCAA group. Total protein showed similar changes, but neither group showed any difference in changes of aspartate aminotransferase, alanine transferase, or platelets. 4) One year postoperatively, the change from the preoperative indocyanine green retention rate at 15 min after intravenous administration tended to be worse in the control group, but not significantly so. 5) In the BCAA group, hyaluronic acid and type IV collagen 7S improved significantly sooner than in the control group.

CONCLUSIONS

BCAA supplementation after hepatectomy promotes rapid improvement in protein metabolism and inhibits progression to liver cirrhosis. Administration of BCAA after hepatectomy is considered beneficial to a patient's nutritional state.

Amelioration of pulmonary emphysema by in vivo gene transfection with hepatocyte growth factor in rats

BACKGROUND

Hepatocyte growth factor (HGF) is an important mitogen and morphogen that contributes to the repair process after lung injury. The goal of the present study was to characterize its role in pulmonary emphysema, which may lead to the development of new treatment strategies with HGF.

METHODS AND RESULTS

HGF mRNA and protein levels in lung tissue and plasma from elastase-induced emphysema rats transiently increased, then declined significantly to below the basal level in a time-dependent manner (P<0.01). Furthermore, changes in HGF were correlated with histologically progressive emphysematous changes and deterioration in pulmonary physiology. Use of the HVJ (hemagglutinating virus of Japan) envelope method resulted in successful transfection of cDNA encoding human HGF, as demonstrated by an efficient expression of HGF in alveolar endothelial and epithelial cells. Transfection of HGF resulted in a more extensive pulmonary vasculature and inhibition of alveolar wall cell apoptosis, and those effects led to improved exercise tolerance and gas exchange (P<0.05), which persisted for more than 1 month.

CONCLUSIONS

Decreased HGF expression due to a failure in sustained endogenous production after injury was associated with emphysema-related histopathologic and physiological changes in the present rat model. In addition, induction of HGF expression by a gene-transfection method resulted in improved pulmonary function via inhibition of alveolar cell apoptosis, enhancement of alveolar regeneration, and promotion of angiogenesis.

Mechanisms of liver fibrosis

Liver fibrosis represents a significant health problem worldwide of which no acceptable therapy exists. The most characteristic feature of liver fibrosis is excess deposition of type I collagen. A great deal of research has been performed to understand the molecular mechanisms responsible for the development of liver fibrosis. The activated hepatic stellate cell (HSC) is the primary cell type responsible for the excess production of collagen. Following a fibrogenic stimulus, HSCs change from a quiescent to an activated, collagen-producing cell. Numerous changes in gene expression are associated with HSC activation including the induction of several intracellular signaling cascades, which help maintain the activated phenotype and control the fibrogenic and proliferative state of the cell. Detailed analyses in understanding the molecular basis of collagen gene regulation have revealed a complex process offering the opportunity for multiple potential therapeutic strategies. However, further research is still needed to gain a better understanding of HSC activation and how this cell maintains its fibrogenic nature. In this review we describe many of the molecular events that occur following HSC activation and collagen gene regulation that contribute to the fibrogenic nature of these cells and provide a review of therapeutic strategies to treat this disease.

HIP/PAP accelerates liver regeneration and protects against acetaminophen injury in mice

Human hepatocarcinoma-intestine-pancreas/pancreatic-associated protein HIP/PAP is a secreted C-type lectin belonging to group VII, according to Drickamer's classification. HIP/PAP is overexpressed in liver carcinoma; however, its functional role remains unclear. In this study, we demonstrate that HIP/PAP is a paracrine hepatic growth factor promoting both proliferation and viability of liver cells in vivo. First, a low number of implanted hepatocytes deriving from HIP/PAP-transgenic mice (<1:1,000) was sufficient to stimulate overall recipient severe combined immunodeficiency liver regeneration after partial hepatectomy. After a single injection of HIP/PAP protein, the percentages of bromodeoxyuridine-positive nuclei and mitosis were statistically higher than after saline injection, indicating that HIP/PAP acts as a paracrine mitogenic growth factor for the liver. Comparison of the early events posthepatectomy in control and transgenic mice indicated that HIP/PAP accelerates the accumulation/degradation of nuclear phospho-signal transducer activator transcription factor 3 and tumor necrosis factor alpha level, thus reflecting that HIP/PAP accelerates liver regeneration. Second, we showed that 80% of the HIP/PAP-transgenic mice versus 25% of the control mice were protected against lethal acetaminophen-induced fulminate hepatitis. A single injection of recombinant HIP/PAP induced a similar cytoprotective effect, demonstrating the antiapoptotic effect of HIP/PAP. Comparison of Cu/Zn superoxide dismutase activity and glutathione reductase-like effects in control and transgenic liver mice indicated that HIP/PAP exerts an antioxidant activity and prevents reactive oxygen species-induced mitochondrial damage by acetaminophen overdose. In conclusion, the present data offer new insights into the biological functions of C-type lectins. In addition, HIP/PAP is a promising candidate for the prevention and treatment of liver failure.

Targeted treatments for cirrhosis

The causes of hepatic scarring (fibrosis) are protean but, unchecked, all result in a common fate--the development of cirrhosis--with gross disruption of the normal liver architecture. Subsequent liver cell dysfunction and portal hypertension give rise to major systemic complications and premature death. Cirrhosis and its sequelae represent a huge, and global, healthcare burden. The success of liver transplantation and the development of efficacious antiviral regimens for hepatitis B and C should not be underestimated, but they also serve to highlight our current inability to manipulate the underlying fibrotic process in many patients with liver disease. Moreover, transplantation as a treatment is limited by organ availability, among other factors. The development of antifibrotic therapies is urgently needed and for this we require a mechanistic and evidence-based approach. Accumulating data from clinical and laboratory studies demonstrate that even advanced fibrosis and cirrhosis are potentially reversible. The hepatic stellate cells have been identified as the pivotal effector cells orchestrating the fibrotic process and, furthermore, reversibility appears to hinge upon their elimination. This review draws on recent scientific advances, and highlights emerging therapeutic interventions in liver fibrosis.

Effect of IL-10 on the expression of HSC growth factors in hepatic fibrosis rat

AIM: To study the effect of IL-10 on the expression of growth factors - transforming growth factor-β1 (TGF-β1), epidermal growth factor (EGF), hepatocyte growth factor (HGF)and platelet-derived growth factor (PDGF) of hepatic stellate cells (HSCs) of hepatic fibrosis rat and the anti-fibrogenic role of exogenous IL-10.

METHODS: Hepatic fibrosis was induced by CCl4 administration intra-peritoneally. Sixty clean male Sprague-Dawley (SD) rats were randomly divided into three groups: normal control group (GN, 8 rats), hepatic fibrosis model group (GC, 28 rats) and IL-10 treated group (GI, 24 rats). At the beginning of the 7^th and 11^th wk, rats in each group were routinely perfused with pronase E and type IV collag-enase through a portal vein catheter and the suspension obtained from the liver was spun by centrifugation with 11% Nycodenz density gradient to isolate HSCs. Histological examination was used to determine the degree of hepatic fibrosis. RT-PCR was employed to analyze mRNA expression from freshly isolated cells. Immunocytochemistry was performed to detect protein expression in primary cultured HSCs.

RESULTS: Rat hepatic fibrosis was developed with the increase of injection frequency of CCl4, and HSCs were successfully isolated. At the 7^th and 11^th wk, TGF-β1, EGF, and HGF mRNA in GC increased obviously compared with GN (P = 0.001/0.042, 0.001/0.001, 0.001/0.001) and GI (P = 0.001/0.007, 0.002/0.001, 0.001/0.001). For TGF-β1, no difference was observed between GI and GN. For EGF, mRNA level in GI increased compared with GN during the 7^th wk (P = 0.005) and 11^th wk (P = 0.049). For HGF, mRNA level in GI decreased compared with GN at the 7^th wk (P = 0.001) and 11^th wk (P = 0.021). Between these two time points, TGF-β1 expression at the 7^th wk was higher than that of the 11^th wk (P = 0.049), but for EGF, the former was lower than the latter (P = 0.022). As for PDGF mRNA, there was no significant difference between these groups, but difference seemed to exist in protein levels. Results by immunocytochemistry of TGF-β1 and EGF were paralleled with the above findings.

CONCLUSION: The expression of TGF-β1, EGF and HGF increased in HSC of hepatic fibrosis rat and decreased after treatment with IL-10. IL-10 plays an anti-fibrogenic role by suppressing growth factors expression.

Treatment of experimental hepatic fibrosis by combinational delivery of urokinase-type plasminogen activator and hepatocyte growth factor genes

PURPOSE

To investigate the effect of combinational delivery of urokinase-type plasminogen activator (uPA) and hepatocyte growth factor (HGF) genes on hepatic fibrosis.

METHODS

Replication-deficient adenoviral vectors expressing either human HGF (AdHGF) or uPA (AduPA) were generated. HGF gene was transferred into primary cultured hepatocytes and uPA gene to hepatic stellate cell (HSC) to investigate the effect on the biological character of cells. Combinational adenoviruses were infused into hepatic fibrosis rats. Serum markers as well as histological and immunohistochemical examination were carried out to test the reversal of hepatic fibrosis.

RESULTS

Transfection of exogenous HGF gene induced expression of c-met/HGF receptor and stimulated hepatocyte proliferation. uPA gene delivered into HSC decreased the amount of collagen types I and III accompanied with the increased expression of matrix metalloproteinase-2. In vivo, the area of extracellular matrix in the fibrotic liver decreased to 72% in AdHGF-treated rats (P<0.01), 64% in the AduPA-treated group (P<0.01), and 51% in bi-genes transfection (P<0.01), compared with that of the controls. Moreover, immunohistochemical staining of collagen types I and III revealed that combinational genes delivery exerted more effect on reversal of hepatic fibrosis than mono-gene transfection.

CONCLUSIONS

Our study indicated that simultaneous delivery of two antifibrotic genes could confer synergistic effect on hepatic fibrosis.

Evaluation of serum concentrations of human hepatocyte growth factor during interferon therapy for chronic hepatitis C

In this study, the serum concentrations of human hepatocyte growth factor (HGF) were examined to clarify the relationship between HGF and interferon (IFN) therapy for hepatitis C. The subjects were 94 patients with chronic hepatitis C who underwent liver biopsy at our institution from 1994 through 1996. These patients were treated with natural IFN-alpha, IFNalpha(2a) and IFNalpha(2b) for periods varying from 12 to 26 weeks. Serum levels of HGF were determined in individual patients just before and after the administration of IFN and at 6 months and 1 year thereafter. The serum concentration of HGF was evaluated using enzyme-linked immunosorbent assay kits. The intra-hepatic location of HGF was explored using an immunoperoxidase-staining method. A positive correlation was found between the degree of HGF expression in the liver and the serum HGF concentrations. The degree of HGF expression in the liver decreased in the virologically sustained responders (SVRs) following IFN therapy. The serum HGF concentrations immediately after IFN therapy were lower than those before therapy in 83% of the patients. The concentrations gradually rose thereafter in about 45% of the non-responders, while it remained low or declined further in about half of the patients in this group. In the SVRs, the serum HGF concentrations declined in 88% of patients immediately after IFN therapy. Thereafter, it remained equally low or declined further in 60% of the SVRs. The serum HGF concentrations at 6 months and 1 year after IFN therapy were significantly lower in the SVRs than in the non-responders. In conclusions, serum HGF concentrations declined following IFN treatment regardless of the virological outcome of treatment. The decrease in serum HGF concentrations results from a decrease in the number of mesenchymal cells producing HGF. Consequently, evaluation of the serum HGF concentration is of clinical value for assessing changes in liver tissues after IFN therapy.

Signal transduction in alcohol-related diseases

This article summarizes the proceedings of a symposium presented at the 12th World Congress on Biomedical Alcohol Research, organized by the International Society for Biomedical Research on Alcoholism, held at the University of Heidelberg in Mannheim, Germany, in September and October 2004. The organizers and chairpersons were Manfred V. Singer and Stephen J. Pandol. The presentations were (1) Ethanol‐induced acinar cell injury, by Minoti V. Apte; (2) Oxidants and antioxidants: signal transduction and alcohol, by Thomá Zima; (3) Anti–TGF‐β strategies for the treatment of chronic liver disease, by Steven Dooley; (4) Immune mechanisms in alcohol‐induced liver disease, by Sören V. Siegmund; and (5) Alcoholic pancreatitis: insights from animal models, by Steven J. Pandol.

Ribozymes against TGFbeta1 reverse character of activated hepatic stellate cells in vitro and inhibit liver fibrosis in rats

BACKGROUND/AIMS

Transforming growth factor beta (TGFbeta1) is considered the key mediator in the process of liver fibrosis. The purpose of this investigation was to evaluate the activity of ribozymes against TGFbeta1 in a cell-free system and activated hepatic stellate cells (HSCs), and antifibrotic effect in activated HSCs in vitro and in rats.

METHODS

Three ribozymes targeting against TGFbeta1 mRNA were designed, and then cloned into the U1 snRNA expression cassette. The chimeric ribozymes were selected for the analysis of their performances in activated HSCs through the detection of their cleavage activities in a cell-free system. After ribozyme-encoding plasmids had been transfected into HSC-T6 cells, the effects of ribozymes on activated HSCs were evaluated through the analysis of proliferation, activation and collagen deposition of HSC-T6. The adenoviral vector expressing the ribozymes was constructed, and then delivered into rat models of hepatic fibrosis induced by carbon tetrachloride.

RESULTS

TGFbeta1 expression was efficiently down-regulated in activated HSCs by U1 snRNA chimeric ribozymes which possessed perfect cleavage activity in a cell-free system. Further studies demonstrated that U1 snRNA chimeric ribozymes inhibited the synthesis of collagen I, reduced deposition of collagen I, suppressed BrdU incorporation, but had no effect on desmin and alpha-SMA expression in transfected HSC-T6 cells. Histological analysis demonstrated that the adenoviral vector expressing ribozyme (Rz803) could alleviate fibrotic pathology in rats treated with carbon tetrachloride.

CONCLUSIONS

The anti-TGFbeta1 ribozymes could reverse the character of activated HSCs in vitro and improve fibrotic pathology in vivo. It indicated that TGFbeta1 could be considered as a novel candidate for a therapeutic agent against hepatic fibrosis.

Matrix metalloproteinase-1 up-regulation by hepatocyte growth factor in human dermal fibroblasts via ERK signaling pathway involves Ets1 and Fli1

In this study, we clarified the molecular mechanism(s) underlying the regulation of matrix metalloproteinase (MMP)-1 gene by hepatocyte growth factor (HGF) in cultured human dermal fibroblasts. HGF induced MMP-1 protein as well as mRNA at a transcriptional level via extracellular signal-regulated kinase (ERK) signaling pathway. The region in the MMP-1 promoter mediating the inducible responsiveness to HGF, defined by the transient transfection analysis of the serial 5′ deletion constructs, contained an Ets binding site. Mutation of this Ets binding site abrogated the HGF-inducible promoter activity. Ets1 up-regulated the expression of MMP-1 promoter activity, whereas Fli1 had antagonistic effects on them. After HGF treatment, the protein level and the binding activity of Ets1 was increased and those of Fli1 was decreased, which were canceled by PD98059. These results suggest that HGF up-regulates MMP-1 expression via ERK signaling pathway through the balance of Ets1 and Fli1, which may be a novel mechanism of regulating MMP-1 gene expression.

Direct electrotransfer of hHGF gene into kidney ameliorates ischemic acute renal failure

In the early phase of kidney transplantation, the transplanted kidney is exposed to insults like ischemia/reperfusion, which is a leading cause of acute renal failure (ARF). ARF in the context of renal transplantation predisposes the graft to developing chronic damage and to long-term graft loss. Hepatocyte growth factor (HGF) has been suggested to support the intrinsic ability of the kidney to regenerate in response to injury by its morphogenic, mitogenic, motogenic and antiapoptotic activities. In the present paper, we examine whether human HGF (hHGF) gene electrotransfer helps in the recovery from ARF in a model of rat renal warm ischemia. We also assess the advantages of this form of gene therapy by direct electroporation of the kidney, given that transplantation offers the possibility of manipulating the organ in vivo. We have compared the therapeutic efficiency of two electroporation methodologies in a rat ARF model. Although they both targeted the same organ, the two methods were applied to different parts of the animal: muscle and kidney. Kidney direct electrotransfer was shown to be more efficient not only in pharmacokinetic but also in therapeutic terms, so it may become a clinically practical alternative in renal transplantation.

Bone marrow-derived mesenchymal stem cells protect against experimental liver fibrosis in rats

AIM: Recent reports have shown the capacity of mesenchymal stem cells (MSCs) to differentiate into hepatocytes in vitro and in vivo. MSCs administration could repair injured liver, lung, or heart through reducing inflammation, collagen deposition, and remodeling. These results provide a clue to treatment of liver fibrosis. The aim of this study was to investigate the effect of infusion of bone marrow (BM)-derived MSCs on the experimental liver fibrosis in rats.

METHODS: MSCs isolated from BM in male Fischer 344 rats were infused to female Wistar rats induced with carbon tetrachloride (CCl₄) or dimethylnitrosamine (DMN). There were two random groups on the 42^nd d of CCl₄:CCl₄/MSCs, to infuse a dose of MSCs alone; CCl₄/saline, to infuse the same volume of saline as control. There were another three random groups after exposure to DMN: DMN10/MSCs, to infuse the same dose of MSCs on d 10; DMN10/saline, to infuse the same volume of saline on d 10; DMN20/MSCs, to infuse the same dose of MSCs on d 20. The morphological and behavioral changes of rats were monitored everyday. After 4-6 wk of MSCs administration, all rats were killed and fibrosis index were assessed by histopathology and radioimmunoassay. Smooth muscle alpha-actin (alpha-SMA) of liver were tested by immunohistochemistry and quantified by IBAS 2.5 software. Male rats sex determination region on the Y chromosome (sry) gene were explored by PCR.

RESULTS: Compared to controls, infusion of MSCs reduced the mortality rates of incidence in CCl₄-induced model (10% vs 20%) and in DMN-induced model (20-40% vs 90%).The amount of collagen deposition and alpha-SMA staining was about 40-50% lower in liver of rats with MSCs than that of rats without MSCs. The similar results were observed in fibrosis index. And the effect of the inhibition of fibrogenesis was greater in DMN10/MSCs than in DMN20/MSCs. The sry gene was positive in the liver of rats with MSCs treatment by PCR.

CONCLUSION: MSCs treatment can protect against experimental liver fibrosis in CCl₄-induced or DMN-induced rats and the mechanisms of the anti-fibrosis by MSCs will be studied further.

An inhibitor of cyclin-dependent kinase, stress-induced p21Waf-1/Cip-1, mediates hepatocyte mito-inhibition during the evolution of cirrhosis

During the evolution of cirrhosis, there is a relative decrease in volume percentage of hepatocytes and a relative increase in biliary epithelial cells and myofibroblasts. This is recognized histopathologically as a ductular reaction and leads to gradual distortion of the normal hepatic architecture. The final or decompensated stage of cirrhosis is characterized by a further decline in hepatocyte proliferation and loss of functional liver mass that manifests clinically as ascites, encephalopathy, and other signs of liver failure. In this report, we tested the hypothesis that p21-mediated hepatocyte mito-inhibition accelerates the evolution of cirrhosis using an established mouse model of decompensated biliary cirrhosis, p21-deficient mice, and liver tissue from humans awaiting liver replacement. Despite the same insult of long-term (12-week) bile duct ligation, mice prone to decompensation showed significantly more oxidative stress and hepatocyte nuclear p21 expression, which resulted in less hepatocyte proliferation, an exaggerated ductular reaction, and more advanced disease compared with compensation-prone controls. Mice deficient in p21 were better able than wild-type controls to compensate for long-term bile duct ligation because of significantly greater hepatocyte proliferation, which led to a larger liver mass and less architectural distortion. Mito-inhibitory hepatocyte nuclear p21 expression in humans awaiting liver replacement directly correlated with pathological disease stage and model of end-stage liver disease scoring. In conclusion, stress-induced upregulation of hepatocyte p21 inhibits hepatocyte proliferation during the evolution of cirrhosis. These findings have implications for understanding the evolution of cirrhosis and associated carcinogenesis. Supplementary material for this article can be found on the HEPATOLOGY website (http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html).

Aqueous extract of Anoectochilus formosanus attenuate hepatic fibrosis induced by carbon tetrachloride in rats

The aim of this study was to investigate the effects of aqueous extract of Anoectochilus formosanus (AFE) on liver fibrogenesis in carbon tetrachloride (CCl4)-induced cirrhosis. Fibrosis was induced in rats by oral administration of CCl4 (20%, 0.5 ml/rat, p.o.) twice a week for 8 weeks. AFE (0.5 and 2.0 g/kg, p.o., daily for 8 weeks) was administered to rats simultaneously. AFE showed reducing actions on the elevated levels of GOT and GPT caused by CCl4. Liver fibrosis in rats induced by CCl4 led to the drop of serum albumin concentration; the AFE increased the albumin concentration. The CCl4-induced liver fibrosis markedly caused liver atrophy and splenomegalia, while AFE increased the liver weight, and decreased the spleen weight. The CCl4-induced liver fibrosis decreased the protein content, and increased collagen contents in rat's liver. AFE significantly increased the contents of protein and reduced the amount of collagen in the liver. In CCl4-treated rats, glutathione concentrations of liver were not affected. AFE significantly increased liver glutathione concentrations. All these results clearly demonstrate that AFE can reduce the liver fibrogensis in rats induced by CCl4.

Hepatocyte growth factor prevents tissue fibrosis, remodeling, and dysfunction in cardiomyopathic hamster hearts

Structural remodeling of the myocardium, including myocyte hypertrophy, myocardial fibrosis, and dilatation, drives functional impairment in various forms of acquired and hereditary cardiomyopathy. Using cardiomyopathic Syrian hamsters with a genetic defect in delta-sarcoglycan, we investigated the potential involvement of hepatocyte growth factor (HGF) in the pathophysiology and therapeutics related to dilated cardiomyopathy, because HGF has previously been shown to be cytoprotective and to have benefits in acute heart injury. Late-stage TO-2 cardiomyopathic hamsters showed severe cardiac dysfunction and fibrosis, accompanied by increases in myocardial expression of transforming growth factor-beta1 (TGF-beta1), a growth factor responsible for tissue fibrosis. Conversely, HGF was downregulated in late-stage myopathic hearts. Treatment with recombinant human HGF for 3 wk suppressed cardiac fibrosis, accompanied by a decreased expression of TGF-beta1 and type I collagen. Suppression of TGF-beta1 and type I collagen by HGF was also shown in cultured cardiac myofibroblasts. Likewise, HGF suppressed myocardial hypertrophy, apoptosis in cardiomyocytes, and expression of atrial natriuretic polypeptide, a molecular marker of hypertrophy. Importantly, downregulation of the fibrogenic and hypertrophic genes by HGF treatment was associated with improved cardiac function. Thus the decrease in endogenous HGF levels may participate in the susceptibility of cardiac tissue to hypertrophy and fibrosis, and exogenous HGF led to therapeutic benefits in case of dilated cardiomyopathy in this model, even at the late-stage treatment.

Gene therapy of liver diseases

Many liver diseases lack satisfactory treatment and alternative therapeutic options are urgently needed. Gene therapy is a new mode of treatment for both inherited and acquired diseases, based on the transfer of genetic material to the tissues. Genes are incorporated into appropriate vectors in order to facilitate their entrance and function inside the target cells. Gene therapy vectors can be constructed on the basis of viral or non-viral molecular structures. Viral vectors are frequently used, due to their higher transduction efficiency. Both the type of vector and the expression cassette determine the duration, specificity and inducibility of gene expression. A considerable number of preclinical studies indicate that a great variety of liver diseases, including inherited metabolic defects, chronic viral hepatitis, liver cirrhosis and primary and metastatic liver cancer, are amenable to gene therapy. Gene transfer to the liver can also be used to convert this organ into a factory of secreted proteins needed to treat conditions that do not affect the liver itself. Clinical trials of gene therapy for the treatment of inherited diseases and liver cancer have been initiated but human gene therapy is still in its infancy. Recent progress in vector technology and imaging techniques, allowing in vivo assessment of gene expression, will facilitate the development of clinical applications of gene therapy.