Elevated serum aminoterminal procollagen type-III-peptide parallels collagen accumulation in rats with secondary biliary fibrosis

Mesenchymal Stromal Cell Therapy in Novel Porcine Model of Diffuse Liver Damage Induced by Repeated Biliary Obstruction

In liver surgery, biliary obstruction can lead to secondary biliary cirrhosis, a life-threatening disease with liver transplantation as the only curative treatment option. Mesenchymal stromal cells (MSC) have been shown to improve liver function in both acute and chronic liver disease models. This study evaluated the effect of allogenic MSC transplantation in a large animal model of repeated biliary obstruction followed by partial hepatectomy. MSC transplantation supported the growth of regenerated liver tissue after 14 days (MSC group, n = 10: from 1087 ± 108 (0 h) to 1243 ± 92 mL (14 days); control group, n = 11: from 1080 ± 95 (0 h) to 1100 ± 105 mL (14 days), p = 0.016), with a lower volume fraction of hepatocytes in regenerated liver tissue compared to resected liver tissue (59.5 ± 10.2% vs. 70.2 ± 5.6%, p < 0.05). Volume fraction of connective tissue, blood vessels and bile vessels in regenerated liver tissue, serum levels of liver enzymes (AST, ALT, ALP and GGT) and liver metabolites (albumin, bilirubin, urea and creatinine), as well as plasma levels of IL-6, IL-8, TNF-α and TGF-β, were not affected by MSC transplantation. In our novel, large animal (pig) model of repeated biliary obstruction followed by partial hepatectomy, MSC transplantation promoted growth of liver tissue without any effect on liver function. This study underscores the importance of translating results between small and large animal models as well as the careful translation of results from animal model into human medicine.

Methyl helicterate inhibits hepatic stellate cell activation through downregulating the ERK1/2 signaling pathway

The present study was to investigate the inhibitory effect of methyl helicterate (MH) on hepatic stellate cells (HSC-T6), primarily elucidating the underlying mechanism of MH against liver fibrosis. HSC-T6 cells were activated by platelet-derived growth factor (PDGF) stimulation, and then the effects of MH on cell viability, cytomembrane integrity, colony, migration, apoptosis, and cell cycle were detected. Moreover, the regulative mechanism of MH on HSCs was investigated by detecting the activation of the extracellular signal-regulated kinase (ERK1/2) signaling pathway. The results showed that MH significantly inhibited HSC-T6 cell viability and proliferation in a concentration-dependent manner. It notably promoted the release of lactate dehydrogenase, destroying cell membrane integrity. MH also markedly inhibited HSC-T6 cell clonogenicity and migration. Moreover, MH treatment significantly induced cell apoptosis and arrested cell cycle at the G2 phase. The further study showed that MH inhibited the expression of ERK1, ERK2, c-fos, c-myc, and Ets-1, blocking the ERK1/2 pathway. In conclusion, this study demonstrates that MH significantly inhibits HSC activation and promotes cell apoptosis via downregulation of the ERK1/2 signaling pathway.

HIF-1 α as a Key Factor in Bile Duct Ligation-Induced Liver Fibrosis in Rats

BACKGROUND

Although several studies suggested hypoxia as an important microenvironmental factor contributing to inflammation and fibrosis in chronic liver diseases, the mechanism of this process is not fully understood. We considered hypoxia inducible factor (HIF-1α) as a key transcription factor in liver fibrosis. The aim of the study was to evaluate the mechanisms of signaling pathway during bile duct ligation (BDL)-induced liver fibrosis in rats.

METHODS

BDL animal model of liver fibrosis was used in the study. Male Wistar rats were divided randomly into two experimental groups: sham group (n = 15), BDL group (n = 30). Hydroxyproline (Hyp) content as a marker of collagen accumulation in liver of rats subjected to BDL was evaluated according to the method described by Gerling B et al. Expression of signaling proteins [integrin β₁ receptor, HIF-1α, nuclear factor kappa B (NF-κB), and transforming growth factor (TGF-β)] was evaluated applying Western-immunoblot analysis. In all experiments, the mean values for six assays ± standard deviations (SD) were calculated. The results were submitted to the statistical analysis using the Student's "t" test, accepting p < 0.05 as significant.

RESULTS

Ligation of bile ducts was found to increase Hyp content in rat liver, accompanied by increase of HIF-1α expression during 10 weeks after BDL. The Hyp level was time dependent. There was not such a difference in control group (p < 0.001). Simultaneously expression of NF-κB, TGF-β, β₁-integrin receptor was significantly elevated starting from sixth week after ligation. Activity of metalloproteinases 2 and 9 in the livers were increased 1 week after surgery and remained increased until the end of the experiment.

CONCLUSIONS

The mechanism of development of liver fibrosis involves activation of Matrix metalloproteinase-2 (MMP-2) and Matrix metalloproteinase-9 (MMP-9), upregulation of HIF-1α transcriptional activity and its related factors, NF-κB and TGF-β. It suggests that they may represent targets for the treatment of the disease.

Intrahepatic Fat Content and Markers of Hepatic Fibrosis in Obese Children

Aim. We evaluated both direct and indirect hepatic fibrosis markers in obese children and their relationship with intrahepatic fat (IHF) content. We also aimed to investigate the possible roles of IHF and fibrosis markers in metabolic syndrome (MS). Methods. 189 obese children were divided into simple obese (SOB), simple steatosis (SS), and nonalcoholic steatohepatitis (NASH) groups according to their IHF and blood alanine transaminase (ALT) levels. They were also scored for the MS components. IHF was assessed as a continuous variable by proton magnetic resonance spectroscopy (1H-MRS). In addition, 30 nonobese children were enrolled as controls and their direct hepatic fibrosis markers and IHF were assessed. Results. Age was related to IHF, NFS, and FIB-4. Both NFS and APRI were related to IHF more significantly than the direct markers. In the estimation of liver function impairment, indirect markers had greater AUROC than direct markers. In MS, IHF and all the fibrosis markers showed similar AUROC. Conclusions. Both direct and indirect markers played a valuable role in evaluating MS. Indirect markers were more effective in distinguishing fatty hepatitis. Age is an important factor underlying hepatic steatosis and fibrosis even in children.

Effects of silymarin and pentoxifylline on matrix metalloproteinase-1 and -2 expression and apoptosis in experimental hepatic fibrosis

BACKGROUND

Many therapeutic strategies have been proposed to treat liver fibrosis, but no drugs have been proved effective. Matrix metalloproteinases (MMPs) have been reported to play a role in some cellular cascades of hepatic inflammation and fibrosis.

OBJECTIVE

The purpose of this study was to investigate whether silymarin and pentoxifylline (PTX) have hepatoprotective and antifibrotic effects in experimental hepatic fibrosis.

METHODS

Sprague-Dawley rats were divided into 4 groups: silymarin group (silymarin 4 mg/kg · d(-1) orally, common bile duct ligation [CBDL]); PTX group (PTX 2 mg/kg · d(-1) intraperitoneally, CBDL); sham group (common bile duct [CBD] exploration only); and control group (saline 1 mL/d orally, CBDL). The CBD was explored and dissected sufficiently to allow passage of a 3/0 silk suture via midline laparotomy. On day 10, all animals were euthanized via cervical dislocation. Then, 5-cm(3) liver samples from the right lobe were removed for histomorphologic evaluation and 3-mL blood samples were taken via cardiac puncture for biochemical analyses. Apoptosis was determined using the terminal deoxynucleotidyltransferase-biotin nick end-label (TUNEL) staining method. Plasma levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and γ-glutamyltransferase; total and indirect bilirubin concentration; hepatic MMP-1 and -2 and tissue inhibitor of MMP (TIMP)-l and -2 activity; and transforming-growth factor (TGF)-β1 concentration were measured. Collagen content was determined by measuring hydroxyproline in liver samples. Malondialdehyde (MDA) was used to estimate lipid peroxidation.

RESULTS

Thirty-two adult male Sprague-Dawley rats were divided into 4 groups: silymarin group (n = 7), PTX group (n = 7), sham group (n = 9), and control group (n = 9). Compared with the control group (14.6 [2.44]), mean (SD) hepatocyte apoptosis (as measured by the ratio of TUNEL-positive cells) was significantly suppressed in the silymarin group (1.2 [0.13]; P = 0.001) and the PTX group (3.8 [0.34]; P = 0.001). Mean (SD) MMP-2 activity in the silymarin group (57.35 [9.89] μg/mL; P = 0.04) and the PTX group (46.88 [9.56] μg/mL; P = 0.04) was significantly lower than that observed in the control group (232.32 [79.76] μg/mL). Compared with the control group (1.37 [0.38] μg/mL), TIMP-2 activity was significantly lower in the silymarin group (0.55 [0.13] μg/mL; P = 0.04) and the PTX group (0.42 [0.09] μg/mL; P = 0.01). Compared with the control group (909.17 [117.35] μg/mL), TGF-β1 was significantly lower in the silymarin group (518.24 [30.34] μg/mL; P = 0.01) and the PTX group (519.57 [47.27] μg/mL; P = 0.01). Histomorphologic changes were significantly greater in the sham group than in the silymarin and PTX groups: hemorrhage (2.44 [0.29] vs 1.29 [0.18] and 1.57 [0.20], respectively; both, P = 0.04); sinusoidal dilatation (2.22 [0.22] vs 1.57 [0.20] and 1.71 [0.18]; both, P = 0.04); presinusoidal polymorphonuclear cell infiltration (3-44 [0.24] vs 2.57 [0.20] and 2.14 [0.26]; P = 0.03 and P = 0.008, respectively); and inflammation (3.44 [0.24] vs 2.57 [0.20] and 2.14 [0.26]; P = 0.03 and P = 0.008, respectively). In the control group, all biochemical markers were elevated, supporting the presence of liver injury. Compared with the control group (630.00 [46.80] U/L), plasma AST activity was significantly lower in the silymarin group (443.11 [78.73]; P = 0.04) and the PTX group (349.42 [34.00]; P = 0.03). Compared with the control group (191.12 [32.93] U/L), plasma ALT activity was significantly lower in the silymarin group (86.14 [4.97]; P = 0.04) and the PTX group (84.14 [11.21]; P = 0.04). MDA concentration was significantly lower in the silymarin group compared with the control group (0.08 [0.01] vs 0.22 [0.03] nmol/mL; P = 0.004); MDA was also significantly lower in the silymarin group than in the PTX group (0.11 [0.02]; P = 0.03).

CONCLUSIONS

Silymarin and PTX were associated with lower histopathologic liver damage, hepatocyte apoptosis, and regulation of extracellular matrix proteins. Lipid peroxidation in hepatocytes was significantly lower in the silymarin group compared with the PTX group. Silymarin and PTX appeared to have hepatoprotective effects in this experimental liver fibrosis model, but further clinical and experimental studies are needed.

Hepatocyte growth factor (HGF) inhibits collagen I and IV synthesis in hepatic stellate cells by miRNA-29 induction

Background

In chronic liver disease, hepatic stellate cells (HSC) transdifferentiate into myofibroblasts, promoting extracellular matrix (ECM) synthesis and deposition. Stimulation of HSC by transforming growth factor-β (TGF-β) is a crucial event in liver fibrogenesis due to its impact on myofibroblastic transition and ECM induction. In contrast, hepatocyte growth factor (HGF), exerts antifibrotic activities. Recently, miR-29 has been reported to be involved in ECM synthesis. We therefore studied the influence of HGF and TGF-β on the miR-29 collagen axis in HSC.

Methodology

HSC, isolated from rats, were characterized for HGF and Met receptor expression by Real-Time PCR and Western blotting during culture induced myofibroblastic transition. Then, the levels of TGF-β, HGF, collagen-I and -IV mRNA, in addition to miR-29a and miR-29b were determined after HGF and TGF-β stimulation of HSC or after experimental fibrosis induced by bile-duct obstruction in rats. The interaction of miR-29 with 3′-untranslated mRNA regions (UTR) was analyzed by reporter assays. The repressive effect of miR-29 on collagen synthesis was studied in HSC treated with miR-29-mimicks by Real-Time PCR and immunoblotting.

Principal Findings

The 3′-UTR of the collagen-1 and −4 subtypes were identified to bind miR-29. Hence, miR-29a/b overexpression in HSC resulted in a marked reduction of collagen-I and -IV synthesis. Conversely, a decrease in miR-29 levels is observed during collagen accumulation upon experimental fibrosis, in vivo, and after TGF-β stimulation of HSC, in vitro. Finally, we show that during myofibroblastic transition and TGF-β exposure the HGF-receptor, Met, is upregulated in HSC. Thus, whereas TGF-β stimulation leads to a reduction in miR-29 expression and de-repression of collagen synthesis, stimulation with HGF was definitely associated with highly elevated miR-29 levels and markedly repressed collagen-I and -IV synthesis.

Conclusions

Upregulation of miRNA-29 by HGF and downregulation by TGF-β take part in the anti- or profibrogenic response of HSC, respectively.

Effect of interferon-alpha, ribavirin, pentoxifylline, and interleukin-18 antibody on hepatitis C sera-stimulated hepatic stellate cell proliferation

Chronic hepatitis C virus (HCV) infection is a major cause of liver fibrosis ultimately leading to cirrhosis. Hepatic stellate cell (HSC) proliferation is crucial in fibrosis development. Current antiviral treatment for HCV involves interferon-alpha (IFN-alpha) and Ribavirin combination therapy. IL-18, a novel cytokine of the IL-1 family of cytokines, is involved in inflammation and may be important in HCV-related inflammation. We hypothesize that block of one of the crucial events will block fibrosis due to HCV. The effect of HCV patient sera with and without IFN-alpha, ribavirin, and IL-18 antibody on HSC proliferation was assessed by [(3)H]-thymidine incorporation assays. Western analysis was used to assess the effect of pentoxifylline (PTX) on c-Jun immediate early gene phosphorylation (p-c-Jun formation). We demonstrate that HCV patient sera-stimulated HSC proliferation. Ribavirin with or without IFN-alpha significantly decreased HCV sera-stimulated HSC proliferation by 50%. Western analysis revealed that HCV serum increased p-c-Jun levels, which were decreased with Ribavirin and PTX. ELISA results showed an elevation of IL-18 levels in HCV sera when compared to normal sera. IL-18 did not stimulate HSC proliferation. However, IL-18 antibody significantly decreased patient sera-stimulated HSC proliferation. In conclusion, Ribavirin decreased HSC proliferation and may act by decreasing p-c-Jun levels in HSCs. IL-18 alone did not stimulate HSC proliferation but IL-18 antibody decreased stimulation, suggesting that IL-18 may work in conjunction with some other factor to increase HSC proliferation.

Resolution of liver cirrhosis using vitamin A-coupled liposomes to deliver siRNA against a collagen-specific chaperone

There are currently no approved antifibrotic therapies for liver cirrhosis. We used vitamin A-coupled liposomes to deliver small interfering RNA (siRNA) against gp46, the rat homolog of human heat shock protein 47, to hepatic stellate cells. Our approach exploits the key roles of these cells in both fibrogenesis as well as uptake and storage of vitamin A. Five treatments with the siRNA-bearing vitamin A-coupled liposomes almost completely resolved liver fibrosis and prolonged survival in rats with otherwise lethal dimethylnitrosamine-induced liver cirrhosis in a dose- and duration-dependent manner. Rescue was not related to off-target effects or associated with recruitment of innate immunity. Receptor-specific siRNA delivery was similarly effective in suppressing collagen secretion and treating fibrosis induced by CCl(4) or bile duct ligation. The efficacy of the approach using both acute and chronic models of liver fibrosis suggests its therapeutic potential for reversing human liver cirrhosis.

Expression of angiotensin II receptor type 1 is reduced in advanced rat liver fibrosis

In this study, we assessed the hypothesis that the expression of angiotensin II receptor type 1 (AGTR1) in liver tissue changes with increasing fibrosis, which would influence the antifibrotic efficacy of AGTR1 blockers. Rats were treated with candesartancilexetil (CAN) initiated 8 or 15 days after bile duct occlusion (BDO). Four weeks after BDO, AGTR1 mRNA and protein were decreased compared to those in sham-operated animals depending on the amount of fibrosis. Starting CAN early, but not late, reduced mRNA of profibrotic TGF-beta, MMP2, and Smad2. However, CAN had no significant effect on collagen I, fibrosis, or intrahepatic resistance. In conclusion, progression of liver fibrosis reduces AGTR1 expression. Therefore, in our model, antifibrotic effects of CAN are insufficient to improve fibrosis or intrahepatic resistance. However, if AGTR1 blockade is started early, a decrease in essential profibrotic molecules is achieved. Hence, early initiation of therapy with AGTR1 blockers may be crucial for the prevention of cirrhosis.

Preliminary study of chemical bile duct embolization to treat hepatolithiasis in rabbits

BACKGROUND

The high recurrence rate of hepatolithiasis is still a problem to be solved. The purpose of the present study was therefore to carry out a preliminary study of the practical value of chemical bile duct embolization (CBDE) to treat hepatolithiasis in rabbits.

METHODS

Chemical bile duct embolization was performed with phenol or absolute ethanol along with N-butyl-cyanoacrylate. The feasibility and effectiveness of CBDE for chemical hepatectomy was assessed by investigating histological changes, biochemistry for hydroxyproline and in situ hybridization for collagen I.

RESULTS

Histologically, the mucosal epithelia of the embolized bile ducts were entirely replaced by collagen fibers, thus effectively eradicating chronic proliferative cholangitis. Also of note, the diseased biliary duct lumens were completely filled with N-butyl-cyanoacrylate, thus effectively preventing calculus formation. The hepatocytes also disappeared completely in the periphery of the embolized lobe, demonstrating that the desired effects of chemical hepatectomy were achieved through CBDE. In a further comparison of embolizing agents, the phenol-cyanoacrylate embolized livers and bile ducts had a higher level of hydroxyproline and collagen I than those embolized with ethanol plus cyanoacrylate.

CONCLUSION

Chemical bile duct embolization is a promising approach to prevent the recurrence of hepatolithiasis and to achieve the effect of chemical hepatectomy.

Effect of Astragalus complanatus flavonoid on anti-liver fibrosis in rats

AIM: To observe the anti-liver fibrosis effect of Astragalus complanatus flavonoids (ACF) in rats.

METHODS: The liver fibrosis model in rats was established by injecting interperitoneally 0.2 mL/100 g 0.5% dimethylnitrosamine, thrice a week. Meanwhile, the rats were administered ACF (30, 60, 120 mg/kg) or colchicine (0.1 mg/kg) once a day for 1 mo. Serum N-propeptide of type I procollagen (PINP) and type III procollagen (PIIINP) was measured using ELISA. Malondialdehyde (MDA) and superoxide dismutase (SOD) in hepatic tissue were evaluated. Matrix metal protease-1 (MMP-1) mRNA expression was assayed by RT-PCR and the protein expression of tissue inhibitor of metal protease-1 (TIMP-1) was analyzed by immunohistochemistry.

RESULTS: In the ACF groups, SOD activity increased and MDA content decreased in comparison to the liver fibrosis model group. The serum PINP and PIIINP contents in ACF-2 and -3 group decreased compared to those in model group. In ACF-2 and -3 group, the expression of MMP-1 mRNA increased significantly and the protein expression of TIMP-1 decreased compared to that in model group.

CONCLUSION: The antifibrotic mechanisms of ACF are associated with its influence on lipid peroxidation and collagen synthesis and degradation.

A preliminary study of applying chemical biliary duct embolization to chemical hepatectomy in rats

The high recurrence of hepatolithiasis, together with the high operative risk of hepatectomy for specially located stones, has not been settled effectively to date. Thus, this study was designed to investigate the feasibility of applying chemical biliary duct embolization (CBDE) to chemical hepatectomy in rats. As revealed in our results, the intrahepatic biliary ducts could be partially or completely occluded by both phenol and absolute ethanol. In addition, the embolization effect was greatly enhanced by further using cyanoacrylate. Also noteworthy is that CBDE resulted in massive death of hepatocytes, which were replaced by proliferated bile ductules and collagen. More importantly, the hepatocytes disappeared completely in the periphery of the embolized lobe where chemical hepatectomy was achieved. As for the comparison of embolic agents, the combination of phenol and cyanoacrylate exhibited even better fibrogenic effects than the combination of ethanol and cyanoacrylate. In conclusion, CBDE might be a promising approach for achieving the effects of chemical hepatectomy. The combination of phenol and cyanoacrylate potentially acted as a more effective agent for biliary duct embolization.

Arterialisation of the portal vein as a model for the induction of hepatic fibrosis: description of microsurgical models in the rat

Within the framework of liver transplantation, arterialisation of the portal vein in the case of non-recanalisable thrombosis has been reactivated. However, one of the consequences of this vascular reconstruction is the development of hepatic fibrosis. Clinical experience has shown that the development of fibrosis can be avoided by reducing portal inflow. We present, as a model for the induction of hepatic fibrosis, techniques of PVA, including transplantation. For PVA, several different techniques were used: the first with reduction of the portal inflow over a stent inserted in the right renal artery (PVA-B), the second with unrestricted flow using an aortic-portal segment (PVA-APS). The third technique was orthotopic liver transplantation with unrestricted portal arterialisation (OLTx-APS). Portal blood flow was measured with an ultrasonic flow probe. To determine the degree of hepatic fibrosis the amount of hydroxyproline was measured. Quantification of relative transcript levels of procollagen I was effected with real-time PCR using the TaqMan technology on a lightcycler instrument. The extracellular matrix was visualised with picro-sirius staining. Measurements with the ultrasonic probe showed a significant increase in flow rates, both with reduced (PVA-B) and unrestricted inflow (PVA-APS; OLTx-APS). The lowest survival rate (58%) was found in the group with unrestricted portal inflow. The reason for this was a high rate of thrombosis in the in the portal vascular tree (4 out of 12). In the OLTx-APS group four animals died within the first 3 postoperative days (69%), as a result of protracted postoperative shock. The overall survival rate was the highest (85%) in the group undergoing PVA with reduction of the portal inflow. PVA with unrestricted inflow was followed by a significant increase in extracellular collagen, which showed a clear correlation with the increase in the amount of hydroxyproline, the level of the mRNA for procollagen I and picro-sirius staining. With the operative PVA techniques presented herein, different arterial flow rates in the portal vein can be investigated. In our opinion these techniques represent an excellent animal model for studying the genesis of fibrosis and antifibrotic substances. By regulating the blood flow in the arterialised portal vein hepatic fibrosis can be reduced or even avoided. After a brief period of learning the microsurgical techniques, the surgeon can limit clamping times and achieve good results with these techniques.

The role of TGF-beta 1 and cytokines in the modulation of liver fibrosis by Sho-saiko-to in rat's bile duct ligated model

Liver fibrosis is an over-accumulation of extra-cellular matrix (ECM) and the hepatic stellate cell (Ito cell) play a central role in the pathogenesis of liver fibrosis. There are a lot of growth factors and cytokines involved in the activation of hepatic stellate cell, including of transforming growth factor (TGF-alpha, TGF-beta1), platelet-derived growth factor (PDGF), interleukin (IL-1alpha,beta, IL-6) and tumor necrosis factor (TNF-alpha). Sho-saiko-to (TJ-9; Xiao-Chai-Hu-Tang in Chinese) was the most popular herbal medicine for the treatment of chronic liver disease in Chinese and Japanese. Our aim of the current study was to examine whether TJ-9 regulated the growth factors and cytokines in the fibrogenesis of bile duct ligated model. Therefore, we assessed the TJ-9's potential in regulating TGF-beta1, PDGF mRNA expression, the amount of IL-1alpha, IL-1beta, IL-6, TNF-alpha and the fibrotic marker "PIII NP" in the serum. Then, using the immunohistochemical stain to observe the TGF-beta1 expression in the tissue. Our results showed that TJ-9 at a dose of 0.5 g/(kgday) significantly reduced the serum level of PIII NP, the mRNA expression of TGF-beta1 and PDGF. For the cytokines involved in the activation of Ito cell, TJ-9 at a dose of 0.5 g/(kgday) significantly suppressed the increasing tendency of IL-1beta and enhanced the production of TNF-alpha. Finally, we concluded that: (1) TJ-9 at a dose of 0.5g/(kgday) significantly reduced the serum fibrotic marker PIII NP in the bile duct ligated model, and its mechanism was partly by means of downregulating the mRNA of TGF-beta1 and PDGF. These results also confirmed by the immunohistochemical staining of TGF-beta1. (2) TJ-9 at a dose of 0.5 g/(kgday) suppressed the increasing tendency of IL-1beta and stimulated the production of TNF-alpha to inhibit Ito cell proliferation and collagen formation.

Sho-saiko-to prevents liver fibrosis induced by bile duct ligation in rats

Hepatic fibrosis is an over-accumulation of extracellular matrix (ECM). It is a result of an imbalance between collagen synthesis and degradation. Matrix metalloproteinase (MMP) has degradative activity against collagen, but tissue inhibitors of metalloproteinase (TIMP) control the active forms of MMP by blocking the active site of MMP. In our study, we established the bile duct ligated model (BDL) in rats to evaluate anti-fibrotic potential of Chinese medicine sho-saiko-to (TJ-9). We assessed the drug's potential in inhibiting collagen accumulation, suppressing procollagen alpha1 types (I) and (III), and TIMP-1 mRNA expression. After administration of TJ-9, hyperbilirubinemia reduced approximately four-fold when compared with BDL-untreated group. TJ-9 also significantly reduced the collagen content and fibrogenic score, as well as downregulated elevated procollagen alpha1 types (I) and (III) and TIMP-1 mRNA level. Finally, we concluded that (1) TJ-9 significantly reduced cholestasis in rats with BDL, (2) TJ-9 markedly reduced the collagen content by 50%, and (3) TJ-9 exerted its antifibrogenic effect by downregulation of the mRNA expression of procollagen alpha1 types (I) and (III), and TIMP-1 in liver tissue.

Effects of Portal Vein Arterialization on Regeneration and Morphology in Liver Transplantation: Investigations Using the Rat Model

BACKGROUND

Portal vein arterialization (PVA) has been proposed as a technical variant in liver transplantation in the case of non-recanalizable thrombosis. The present study investigates the effects of the arterialized portal vein on the function, morphology, and regenerative behavior of the liver.

METHODS

Different PVA techniques, including orthotopic liver transplantation, were used in a rat model. Portal blood flow was measured using a ultrasonic flowmeter. The regeneration capacity was determined on the basis of the increase of liver weight and the proliferating cell nuclear antigen index. The amount of hydroxyproline and the transcript levels of procollagen I were measured to determine the degree of fibrosis. The extracellular matrix was visualized with Picro-Sirius staining.

RESULTS

The measurements obtained with an ultrasonic probe revealed a significant increase in portal blood flow after PVA. The regeneration capacity in the groups after PVA with no flow reduction was comparable to that of the control. Liver transplantation and PVA with no flow reduction was followed by a significant increase (four- to sixfold) in the amount of hydroxyproline and the level of the mRNA for procollagen I. In the Picro-Sirius staining, periportal and perivascular fibrosis with incipient formation of septa was seen. After reduction of the portal blood flow, these effects were significantly less pronounced.

CONCLUSIONS

These operative techniques represent an excellent small animal model for studying the mechanism of liver regeneration and the genesis of fibrosis in liver and vessel tissue. The presenting findings indicate that the negative effects of "overarterialization" may be largely avoided by reducing portal blood flow. This implies that permanent PVA in clinical liver transplantation should be performed only in conjunction with a down-regulation of portal flow.

Integration of clinical and gene expression endpoints to explore furan-mediated hepatotoxicity

Molecular techniques, such as cDNA microarrays, are being used to aid in the elucidation of the mechanisms of toxicity of a variety of compounds. In this study, we evaluate the molecular effects of furan in the rat liver. Sprague-Dawley rats were exposed to 4 or 40 mg/kg furan for up to 14 days. Furan induced an initial degenerative and necrotic phenotype that was followed by inflammation and fibrosis, consistent with previous observations for this compound. RNA was harvested from each lobe of the liver at several time points to observe whether lobe-specific gene expression effects occurred. Similar gene expression changes were observed in all lobes, however the magnitude of gene expression change was more pronounced in the right lobe. Finally, to help determine the correlation between gene expression changes and liver pathology, we applied traditional microarray visualization tools to the assessment of clinical chemistry and pathology parameters.

Histological improvements after a three-year lamivudine therapy in patients with chronic hepatitis B in whom YMDD mutants did not or did develop

OBJECTIVE

The long-term effects of lamivudine and the influence of YMDD mutants on the histology of chronic hepatitis B are not known.

METHODS

3-year lamivudine therapy was given to 16 patients with chronic hepatitis B. YMDD mutants did not develop in 9 patients (group A), while they appeared in the remaining 7 patients (group B).

RESULTS

Biochemical and virological responses were invariably achieved in the 9 patients without YMDD mutants, while virological breakthroughs with or without biochemical relapses occurred in all 7 patients with such mutants. All 16 patients accomplished histological improvement, with the total histology activity index (HAI) score decreasing from 11.3 +/- 3.0 to 4.1 +/- 1.7 (p < 0.001). The total HAI score decreased from 11.6 +/- 3.8 to 3.4 +/- 1.3 in the 9 patients in group A (p < 0.001). Although to a significantly lesser extent (p < 0.02), the total HAI score also decreased in the 7 patients in group B from 10.9 +/- 1.0 to 5.0 +/- 1.7 (p < 0.001).

CONCLUSION

The results obtained indicate that 3-year lamivudine therapy can induce histological improvements, regardless of the appearance of YMDD mutants accompanied by virological breakthroughs and biochemical relapses.

Selective Na+/H+ exchange inhibition by cariporide reduces liver fibrosis in the rat

The aim of this study was to evaluate the effect of cariporide, a selective Na(+)/H(+) exchange inhibitor, on isolated and cultured hepatic stellate cells (HSCs) and in 2 in vivo models of rat liver fibrosis. Platelet-derived growth factor (PDGF)-induced HSC proliferation, evaluated by measuring the percentage of bromodeoxyuridine-positive cells, was significantly inhibited by cariporide, with a maximal effect at 10 micromol/L. Incubation with cariporide did not inhibit PDGF-induced extracellular-regulated kinase 1/2 (ERK1/2), Akt (a downstream component of the phosphatidylinositol [PI]-3 kinase pathway), and protein kinase C (PKC) activation but reduced PDGF-induced activation of the Na(+)/H(+) exchanger, with a maximal effect at 10 micromol/L. Rats treated with dimethylnitrosamine (DMN; 10 mg/kg) for 1 and 5 weeks received a diet with or without 6 ppm cariporide. Treatment with cariporide reduced the degree of liver injury, as determined by alanine aminotransferase (ALT) values, also when administered after the induction of hepatic damage. This was associated with reduced HSC activation and proliferation and reduced collagen deposition, as determined by morphometric evaluation of alpha-smooth muscle actin (SMA)/proliferating cell nuclear antigen-positive cells and percentage of Sirius red-positive parenchyma, respectively. Moreover, cariporide was also able to reduce alpha(1)I procollagen messenger RNA (mRNA) expression. Similar effects were observed in bile duct-ligated (BDL) rats. In conclusion, selective inhibition of the Na(+)/H(+) exchanger by cariporide may represent an effective therapeutic strategy in the treatment of hepatic fibrosis.

Intrasplenic transplantation of syngenic hepatocytes modified by IFN-gamma gene ameliorates hepatic fibrosis in rats

Transplanted hepatocytes are ideal carriers for exogenous genes in liver gene therapy. The present study investigated the anti-fibrogenic effects of intrasplenically transplanted hepatocytes modified with interferon gamma (IFN-gamma) gene on cirrhotic rats. Hepatocytes isolated from normal Sprague-Dawley (SD) rats were transfected with an adenoviral vector encoding human IFN-gamma gene (AdCMVhIFN-gamma) and transplanted into the spleens of syngenic recipients with ongoing liver fibrosis induced by carbon tetrachloride (CCl(4)). Histology was assessed, and liver hydroxyproline was detected. Additionally, serum procollagen type III (PIIINP) levels and hepatic collagenase activity were measured to determine hepatic collagen synthesis and degradation. Transplantation with AdCMVhIFN-gamma transfected hepatocytes ameliorated the histological outcome of liver fibrosis by reducing liver collagen content and decreasing hepatic hydroxyproline. Additionally, IFN-gamma transfected hepatocytes reduced serum PIIINP levels and increased hepatic collagenase activity. Our data suggest that transplantation of IFN-gamma transfected hepatocytes may reduce the pace of liver fibrosis by inhibiting the synthesis and enhancing the degradation of hepatic collagen.

Modulation of collagen XVIII/endostatin expression in lobular and biliary rat liver fibrogenesis

BACKGROUND/AIMS

The liver is the major source of collagen XVIII (C18), the precursor of the angiogenesis inhibitor endostatin. In human liver C18 is mainly expressed by hepatocytes. However, its quantitative and temporospatial expression patterns during liver fibrogenesis are unknown.

METHODS

We used RNA quantification and in situ hybridization combined with cell-specific markers to study C18 compared to procollagen alpha1(I) and tissue inhibitor of metalloproteinases-1 (TIMP-1) mRNA expression in acute (single dose of CCl4) and chronic (biliary) rat liver fibrogenesis.

RESULTS

C18 transcripts were only found in hepatocytes and bile duct epithelia of normal and fibrotic livers, and occasionally in arterial myocytes and hepatic stellate cells. 72 h after CCl4 injection, C18 mRNA levels remained unchanged, while procollagen alpha1(I) mRNA was increased at 72 h and TIMP-1 mRNA peaked at 12 h (P < 0.05). In biliary fibrosis C18 mRNA levels increased 1.8-fold, contrasting with 20- and 4-fold elevated procollagen alpha1(I) and TIMP-1 transcript levels, respectively.

CONCLUSIONS

Hepatocytes and bile duct epithelia are the predominant sources of C18 in normal and fibrotic rat liver. Contrary to procollagen alpha1(I) and TIMP-1, C18 expression remains constant in acute fibrogenesis and is upregulated in biliary fibrosis. Modulation of epithelial C18 expression and its processing to endostatin could allow a liver-specific anticancer therapy.

Antifibrotic effect of silymarin in rat secondary biliary fibrosis is mediated by downregulation of procollagen alpha1(I) and TIMP-1

BACKGROUND/AIMS

Silymarin reduces hepatic collagen accumulation by 35% in rats with secondary biliary cirrhosis. The aim of the present study was to explore its antifibrotic mechanism.

METHODS

Thirty female adult Wistar rats were allocated to (1) bile duct occlusion, (2) bile duct occlusion and oral silymarin at 50 mg/kg per day, and (3) sham operation and oral silymarin at 50 mg/kg per day. Steady-state mRNA levels for procollagen alpha1(I), tissue inhibitor of metalloproteinases-1 (TIMP-1), and transforming growth factor (TGF) beta1 were determined by multi-probe ribonuclease protection assay.

RESULTS

After 6 weeks of bile duct occlusion, liver collagen content was increased 12-fold, when compared with the sham-operated controls. These animals displayed 17-, 6.5- and 16-fold higher transcript levels for procollagen alpha1(I), TIMP-1 and TGFbeta1 (P < 0.01). Silymarin downregulated elevated procollagen alpha1(I), TIMP-1 and TGFbeta1 mRNA levels by 40-60% (P < 0.01). These lowered hepatic profibrogenic transcript levels correlated with decreased serum levels of the aminoterminal propeptide of procollagen type III.

CONCLUSIONS

Silymarin suppresses expression of profibrogenic procollagen alpha1(I) and TIMP-1 most likely via downregulation of TGFbeta1 mRNA in rats with biliary fibrosis. The serum procollagen type III propeptide level mirrors profibrogenic mRNA expression in the liver.

An oral endothelin-A receptor antagonist blocks collagen synthesis and deposition in advanced rat liver fibrosis

BACKGROUND & AIMS

Endothelin 1 induces contraction, proliferation, and collagen synthesis of hepatic stellate cells in vitro, which may be mediated via the endothelin A receptor. It is unknown if specific blockade of the endothelin A receptor inhibits hepatic fibrosis in vivo.

METHODS

Groups of 10-20 rats with bile duct occlusion were treated with the nonpeptide endothelin-A receptor antagonist LU 135252 at 80 mg. kg(-1). day(-1) from week 1-6 or from week 4-6, or with LU at 10 mg. kg(-1). day(-1) from week 1-6. Animals with bile duct occlusion alone and sham-operated rats without or with LU at 80 mg. kg(-1). day(-1) over 6 weeks served as controls. After 6 weeks, parameters of fibrogenesis were determined.

RESULTS

LU treatment led to improved histology, paralleled by a dose-dependence up to 60% reduction of liver collagen, even when administered at an advanced fibrosis stage. This was accompanied by a decreased messenger RNA of hepatic procollagen alpha1(I) and tissue inhibitor of metalloproteinase 1, 2 major effectors of fibrosis, and of serum procollagen type III, a surrogate marker of liver fibrogenesis.

CONCLUSIONS

Selective endothelin-A receptor blockade can dramatically reduce collagen accumulation in rat secondary biliary fibrosis, a model refractory to most potential antifibrotic agents. Endothelin-A receptor antagonists are promising antifibrotic agents in chronic liver disease.

Enzyme-linked immunosorbent assay for serum procollagen type III peptide in rats with hepatic fibrosis

The process of hepatic fibrosis, and the changes in contents of hepatic hyproxyproline (HYP) and serum procollagen type III peptide (PIIINP) were examined in two rat models for hepatic fibrosis, i.e. bile duct ligation/scission (BDL/s)- and dimethylnitrosamine (DMN)-induced models. In addition, an expression of type III collagen mRNA in the liver of BDL/s model was also examined. In BDL/s model, hepatic fibrosis started at 2 weeks after operation (WAO) and cirrhosis with prominent bile duct hyperplasia was detected at and after 5 WAO. Serum PIIINP content measured using a modified double armed inhibition enzyme-linked immunosorbent assay (ELISA) method proposed by us started to increase at 1 WAO and continued to increase thereafter. Hepatic HYP content measured colorimetrically started to increase at 3 WAO and it continued to increase until 7 WAO. An expression of type III collagen mRNA in the liver was enhanced at and after 2 WAO, especially at 4 and 5 WAO. In DMN model, marked hepatic fibrosis was detected at 1 week after the last DMN administration (WAA), and the degree of fibrosis was apparently reduced at 4 WAA. Serum PIIINP content prominently increased at 1 WAA and decreased at and after 3 WAA. Hepatic HYP content showed a marked increase at 1 WAA and decreased thereafter. The present results indicated that the sequences of hepatic fibrosis, hepatic HYP content and serum PIIINP content were well correlated with each other in both BDL/s and DMN models. In conclusion, ELISA system for the detection of serum PIINP content is considered to be reliable method for assessment of cirrhotic liver, and the present two rat models for liver fibrosis/cirrhosis seems to be a good tool for researching antifibrotic agents.

Chronic hepatitis C: T-helper1/T-helper2 imbalance could cause virus persistence in peripheral blood

Interferon gamma (IFN gamma) and interleukin 4, 10 and 12 (IL-4, -10, -12) production was measured in whole peripheral blood (WPB) and peripheral blood mononuclear cells (PBMC) of 10 chronic hepatitis C (CHC) patients. The level of IFN gamma in supernatants in mitogen-activated WPB was lower than in healthy donors. IL-10 served as a possible downregulative factor for IFN gamma, since its spontaneous IL-10 production was enhanced in CHC. Neutralization of IL-10 partly restored IFN gamma response in CHC patients. Recombinant IL-12 (rIL-12) also enhanced IFN gamma of CHC patients, but IL-12 production was decreased in CHC. Thus, IFN gamma production deficiency in CHC patients is secondary to blockage by high levels of IL-10-impaired IL-12 production.

Effects of simvastatin, pentoxifylline and spironolactone on hepatic fibrosis and portal hypertension in rats with bile duct ligation

AIMS/METHODS

Our aim was to study the antifibrotic and hemodynamic effects of simvastatin (SMV), pentoxifylline (PTX) and spironolactone (SPN), three drugs which may have antifibrotic and/or portal hypotensive properties, in a model of hepatic fibrosis and portal hypertension induced in rats by bile duct ligation. A blind study was performed in five groups of 53 Sprague-Dawley rats: sham, placebo (PL), SMV (2.5 mg x kg(-1) x J(-1)), PTX (50 mg x kg(-1) x J(-1)) and SPN (100 mg x kg(-1) x J(-1)). Drugs were administered by daily gavage over a 4-week period as soon as bile duct ligation was performed. At day 28, the following parameters were evaluated: area of hepatic fibrosis by image analysis after staining collagen with picrosirius and plasma concentrations of hyaluronate, splanchnic and systemic hemodynamics (radiolabeled microspheres).

RESULTS

Portal venous pressure (PL: 15.5+/-1.5, SMV: 15.8+/-2.5, PTX: 15.9+/-1.8, SPN: 13.5+/-2.1 mmHg, p<0.05) and porto-systemic shunts (PL: 30+/-31, SMV: 18+/-27, PTX: 25+/-24, SPN: 5+/-4%, p<0.05) were significantly reduced in the SPN group; other hemodynamic parameters were not significantly altered. There was a significant correlation between portosystemic shunts and portal pressure (r(s)=0.47, p<0.01). The area of fibrosis was not significantly different among the four groups of bile duct ligated rats (PL: 8.7+/-3.9, SMV: 7.1+/-3.6, PTX: 7.8+/-2.7, SPN: 6.6+/-3.3%) but was higher than in sham rats (1.5+/-0.5%, p<0.001). Hyaluronate was significantly higher in bile duct ligated rats (from 374+/-162 to 420+/-131 microg/l, among the four groups) than in sham rats (52+/-16 microg/l, p<0.0001).

CONCLUSIONS

In this model, none of the drugs prevented hepatic fibrosis. On the other hand, spironolactone decreased portal pressure and prevented porto-systemic shunts. Therefore, this drug may have beneficial effects in patients with early portal hypertension.