Reversibility of hepatic fibrosis: from the first report of collagenase in the liver to the possibility of gene therapy for recovery

Investigation of the therapeutic effect of Yinchen Wuling Powder on CCl4-induced hepatic fibrosis in rats by 1H NMR and MS-based metabolomics analysis

Hepatic fibrosis (HF) is a typical consequence of various chronic liver diseases, and there is still no ideal drug for its treatment. Yinchen Wuling Powder (YCWLP), a famous traditional Chinese medicine prescription, is effective for the treatment of icteric hepatitis, hepatic fibrosis, non-alcoholic fatty liver disease and other liver diseases in clinical practices, however, the underlying mechanisms of YCWLP on HF is still unclear. In this study, ¹H NMR and MS-based metabolomics analysis along with body weight change, serum liver function indexes, serum liver fibrosis index and histopathological observations of liver were applied to evaluate the therapeutic effect of YCWLP on hepatic fibrosis and the mechanism associated with this. The results of the pharmacodynamics study show that YCWLP has a significant therapeutic effect on hepatic fibrosis. As for the metabolomics research, 7 metabolites in the plasma samples, 28 in the urine samples and 6 in the liver samples were significantly altered due to the protective effect of YCWLP on CCl₄-induced hepatic fibrosis. These endogenous metabolites are involved in amino acid metabolism, carbohydrate metabolism, glycerophospholipid metabolism and gut bacteria metabolism. These findings suggest that YCWLP could treat hepatic fibrosis by promoting urea circulation and reducing blood ammonia accumulation, improving carbohydrate metabolism and reducing oxidative stress, improving glycerophospholipid metabolism and protecting cell membrane, and regulating intestinal flora metabolism.

Curcumol may reverse early and advanced liver fibrogenesis through downregulating the uPA/uPAR pathway

Previous studies have suggested strong antifibrotic activity of curcumol in the liver; the underlying mechanisms of which, however, remain largely unknown. Aiming to investigate the role of curcumol in regulating early and advanced liver fibrosis, we designed a rat model with advanced liver fibrosis and cell model with an initial fibrotic stage. Model rats induced by CCl₄ and alcohol presented advanced liver fibrosis with complete fibrous septa. The administration of curcumol (25 mg/kg or 50 mg/kg) resulted in reversal of liver fibrosis. Leptin-administrated liver sinusoidal endothelial cells presented defenestration and basement membrane components deposition, including laminin (LN) and type IV collagen (Col IV), the characteristics of capillarization by scanning electron microscopy and immunofluorescence assays. After treatment with curcumol (12.5, 25, or 50 mg/L), defenestration was restored and the levels of LN and Col IV were decreased, consistent with the rat model. Quantitative polymerase chain reaction and Western blot results revealed that increased levels of urokinase plasminogen activator (uPA)/ uPA receptor (uPAR) were observed both in vivo and in vitro, curcumol significantly reduced uPA/uPAR at both the mRNA and protein levels. Reduction of uPA/uPAR may be synergistic with matrix metallopeptidase 13 to reverse liver fibrogenesis. In conclusion, curcumol protects liver from phenotypic changes in the early and advanced fibrogenesis, possibly through uPA/uPAR pathway.

Metalloproteinases in non-alcoholic fatty liver disease and their behavior in liver fibrosis

Non-alcoholic fatty liver disease (NAFLD) is a clinical entity of high prevalence in the world characterized by fatty infiltration of liver tissue in the absence of alcohol consumption. The natural history of the disease develops in successive phases reflected in different histological stages, with 10-20% of patients developing liver cirrhosis and fibrosis. Fibrosis is a basic connective tissue lesion defined by the increase of the fibrillary extracellular matrix (ECM) components in a tissue or organ. Matrix metalloproteinases (MMPs) constitute a family of endopeptidases, which are involved in ECM and basement membranes components degradation. Fibrogenic process is characterized by altered ECM composition, associated with modifications in MMPs behavior. The active cross-talk between adipose tissue and liver can be altered in pathologies associated to insulin resistance (IR), such as NAFLD. The role of adipokines on MMPs behavior in the liver could be partly responsible of liver damage during IR. The aim of this revision is to describe the behavior of MMPs in NAFLD and its role in the associated fibrosis.

Therapeutic effect of hepatocyte growth factor-secreting mesenchymal stem cells in a rat model of liver fibrosis

Bone marrow-derived mesenchymal stromal cells (MSCs) have been reported to be beneficial for the treatment of liver fibrosis. Here, we investigated the use of genetically engineered MSCs that overexpress hepatocyte growth factor (HGF) as a means to improve their therapeutic effect in liver fibrosis. Liver fibrosis was induced by intraperitoneal injection of dimethylnitrosamine. HGF-secreting MSCs (MSCs/HGF) were prepared by transducing MSCs with an adenovirus carrying HGF-encoding cDNA. MSCs or MSCs/HGF were injected directly into the spleen of fibrotic rats. Tissue fibrosis was assessed by histological analysis 12 days after stem cell injection. Although treatment with MSCs reduced fibrosis, treatment with MSCs/HGF produced a more significant reduction and was associated with elevated HGF levels in the portal vein. Collagen levels in the liver extract were decreased after MSC/HGF therapy, suggesting recovery from fibrosis. Furthermore, liver function was improved in animals receiving MSCs/HGF, indicating that MSC/HGF therapy resulted not only in reduction of liver fibrosis but also in improvement of hepatocyte function. Assessment of cell and biochemical parameters revealed that mRNA levels of the fibrogenic cytokines PDGF-bb and TGF-β1 were significantly decreased after MSC/HGF therapy. Subsequent to the decrease in collagen, expression of matrix metalloprotease-9 (MMP-9), MMP-13, MMP-14 and urokinase-type plasminogen activator was augmented following MSC/HGF, whereas tissue inhibitor of metalloprotease-1 (TIMP-1) expression was reduced. In conclusion, therapy with MSCs/HGF resulted in an improved therapeutic effect compared with MSCs alone, probably because of the anti-fibrotic activity of HGF. Thus, MSC/HGF represents a promising approach toward a cell therapy for liver fibrosis.

Fibrogenesis and Carcinogenesis in Nonalcoholic Steatohepatitis (NASH): Involvement of Matrix Metalloproteinases (MMPs) and Tissue Inhibitors of Metalloproteinase (TIMPs)

Nonalcoholic steatohepatitis (NASH) is emerging worldwide because life-styles have changed to include much over-eating and less physical activity. The clinical and pathophysiological features of NASH are very different from those of HBV- and HCV-chronic liver diseases. The prognosis of NASH is worse among those with nonalcoholic fatty liver diseases (NAFLD), and some NASH patients show HCC with or without cirrhosis. In the present review we discuss fibrogenesis and the relationship between fibrosis and HCC occurrence in NASH to clarify the role of MMPs and TIMPs in both mechanisms. Previously we proposed MMP and TIMP expression in the multi-step occurrence of HCC from the literature based on viral-derived HCC. We introduce again these expressions during hepatocarcinogenesis and compare them to those in NASH-derived HCC, although the relationship with hepatic stem/progenitor cells (HPCs) invasion remains unknown. Signal transduction of MMPs and TIMPs is also discussed because it is valuable for the prevention and treatment of NASH and NASH-derived HCC.

Application of virtual touch tissue quantification to diagnose liver fibrosis in mice

AIM: To assess the application of virtual touch tissue quantification (VTQ) in the diagnosis of liver fibrosis in mice.

METHODS: Forty male mice were randomly divided into control, CCl₄-1 wk, CCl₄-4 wk and CCl₄-8 wk groups. At different time points, VTQ value was calculated, and aspartate aminotransferase (AST), alanine aminotransferase (ALT), collagen Ⅳ (Ⅳ-C), hyaluronic acid (HA) and laminin (LN) were measured. Liver tissues were taken for pathological analysis.

RESULTS: HE staining indicated that the 1-wk group showed a small amount of necrosis and inflammatory cell infiltration; the 4-wk group showed significant hepatocyte ballooning degeneration and some necrosis; the 8-wk group showed a large amount of inflammatory cell infiltration and abnormal lobular structure; and the control group had normal lobular architecture. Compared with the control group with a few collagen fibers in the vessel wall, the number of collagen fibers increased significantly in the 1-, 4- and 8-wk groups. The fibrous septa was obvious in the 4-wk group and pseudolobule formation with proliferated collagen fibers was present in the 8-wk group. Compared with the control group, AST, ALT, Ⅳ-C, LN and HA showed no significant differences in the 1-wk group (P > 0.05), but were significantly different in the 4- and 8-wk groups (P < 0.01, P < 0.001). VTQ value showed no significant difference between the control group and 1-wk group (P > 0.05), but differed significantly between the control group and 4- and 8-wk groups (P < 0.01, P < 0.001).

CONCLUSION: VTQ can be used as a new method for the diagnosis of liver fibrosis.

S-nitroso-N-acetylcysteine attenuates liver fibrosis in experimental nonalcoholic steatohepatitis

S-Nitroso-N-acetylcysteine (SNAC) is a water soluble primary S-nitrosothiol capable of transferring and releasing nitric oxide and inducing several biochemical activities, including modulation of hepatic stellate cell activation. In this study, we evaluated the antifibrotic activity of SNAC in an animal model of nonalcoholic steatohepatitis (NASH) induced in Sprague-Dawley rats fed with a choline-deficient, high trans fat diet and exposed to diethylnitrosamine for 8 weeks. The rats were divided into three groups: SNAC, which received oral SNAC solution daily; NASH, which received the vehicle; and control, which received standard diet and vehicle. Genes related to fibrosis (matrix metalloproteinases [MMP]-13, -9, and -2), transforming growth factor β-1 [TGFβ-1], collagen-1α, and tissue inhibitors of metalloproteinase [TIMP-1 and -2] and oxidative stress (heat-shock proteins [HSP]-60 and -90) were evaluated. SNAC led to a 34.4% reduction in the collagen occupied area associated with upregulation of MMP-13 and -9 and downregulation of HSP-60, TIMP-2, TGFβ-1, and collagen-1α. These results indicate that oral SNAC administration may represent a potential antifibrotic treatment for NASH.

Telmisartan plus propranolol improves liver fibrosis and bile duct proliferation in the PSC-like Abcb4-/- mouse model

BACKGROUND

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease leading to cirrhosis and cholangiocellular carcinoma. Inhibitors of the renin-angiotensin system or the sympathetic nervous system delay liver fibrogenesis in animal models.

AIMS

We investigated the antifibrotic potential of telmisartan, an angiotensin II type 1 receptor antagonist, and the β-adrenoceptor blocker propranolol in the PSC-like Abcb4 knockout mouse model.

METHODS

Sixty-five Abcb4 (-/-) mice were treated with telmisartan for 3 or 5 months (T) and with telmisartan plus propranolol for 3, 5, or 8 months (TP), or for 2 or 5 months starting with a delay of 3 months (TP delayed). Liver hydroxyproline content, inflammation, fibrosis, and bile duct proliferation were assessed; fibrosis-related molecules were analyzed by real-time polymerase chain reaction and Western blotting.

RESULTS

Compared to controls, telmisartan monotherapy had no significant influence on hydroxyproline; however, telmisartan plus propranolol reduced hydroxyproline (TP 3 months, p = 0.008), fibrosis score (TP 3 months and TP 8 months, p = 0.043 and p = 0.008, respectively; TP delayed 8 months, p < 0.0005), bile duct proliferation (TP 8 months and TP delayed 8 months, p = 0.006 and p < 0.0005, respectively), and procollagen α1(I), endothelin-1, TIMP-1 and MMP3 mRNA as well as α-SMA, CK-19, and TIMP-1 protein.

CONCLUSIONS

Telmisartan plus propranolol reduces liver fibrosis and bile duct proliferation in the PSC-like Abcb4 (-/-) mouse model, even when started at late stages of fibrosis, and may thus represent a novel therapeutic option for cholestatic liver diseases such as PSC.

Changes in Activities of MMP in Alcohol and Thermally Oxidized Sunflower Oil-Induced Liver Damage: NAC Antioxidant Therapy

Liver fibrosis is the result of imbalance between extracellular matrix (ECM) synthesis and breakdown. Ethanol-induced increase in redox state is a sign of major change in hepatic metabolism and this inhibits tricarboxylic acid cycle activity and, fatty acid oxidation and increases fatty acid uptake, thus predisposing fatty liver. Fibrotic changes induced by alcohol are provoked by diets rich in PUFA. Heating of oils rich in PUFA produces toxic volatile and nonvolatile compounds, which aggravate liver damage. Hepatotoxicity was induced in male Wistar rats by administering alcohol (20%) and thermally oxidized sunflower oil (Delta PUFA) (15%). When N-acetyl cyteine (NAC) (150 mg/kg body weight), an ROS scavenger, was administered, there was a reversal of liver damage, which was demonstrated biochemically. Matrix metalloproteinases (MMPs), being potential biochemical indicators of fibroproliferation, were estimated in the present study, which were found to be altered in alcohol, Delta PUFA, and alcohol + Delta PUFA. The altered activities of MMPs in these groups were effectively modulated by treatment with NAC. Thus, in this study, NAC was found to modulate the effect of alcohol and Delta PUFA-induced liver damage.

Evaluation of the spontaneous reversibility of carbon tetrachloride-induced liver cirrhosis in rabbits

There is a general consensus that liver fibrosis in humans is potentially reversible, while scepticism prevails on the concept that cirrhosis can be truly reversed. The availability of suitable experimental models is fundamental for disease research. The experimental murine model of liver cirrhosis induced by carbon tetrachloride (CCl(4)) reproduces both the histological picture of the postnecrotic cirrhosis and its biochemical and clinical parameters. Normal hepatic structure is modified by formation of regeneration nodules. Fibrosis represents a morphological element of disease and an effect of hepatocyte necrosis. However, the relevance for research of this well-established model of liver cirrhosis is hampered by some spontaneous cirrhosis regression reported in mice and rats. It has been reported that CCl(4) also induces experimental liver cirrhosis in rabbits, but it is not known whether the process is reversible in this species. The aim of our study was to investigate this question. Male New Zealand White rabbits were treated intragastrically with CCl(4) or the vehicle only for 19 weeks and groups were sacrificed three and five months after treatment interruption. Cirrhotic and control livers were processed for routine light microscopy and for morphometric study of fibrosis by semiquantitative evaluation. The degree of fibrosis was based on the Knodell's scoring system.

Controlled release of matrix metalloproteinase 1 with or without skeletal myoblasts transplantation improves cardiac function of rat hearts with chronic myocardial infarction

Skeletal myoblast transplantation has been applied clinically for severe ischemic cardiomyopathy. Matrix metalloproteinase 1 (MMP-1) reduces fibrosis and prevents the progress of heart failure. We hypothesized that MMP-1 administration to the infarct area enhances the efficacy of skeletal myoblast transplantation. The controlled release of MMP-1 improved cardiac functions of rats with chronic myocardiac infarction with or without transplantation of skeletal myoblasts. Improvement in cardiac function and small fibrotic area inside the infarcted area were observed compared with those of myoblast transplantation. In conclusion, controlled release of MMP-1 was effective in cardioprotection in postmyocardial infarction although the combination with cell transplantation showed the similar effect.

Inhibition of hepatic stellate cell proliferation by heat shock protein 90 inhibitors in vitro

Hepatic stellate cells (HSCs) play an important role in the development of hepatic fibrosis. Heat shock protein 90 (Hsp90) is essential for the maturation and activity of a varied group of proteins involved in signal transduction and cell cycle regulation. In this study, we found that two Hsp90 inhibitors, VER-49009 and its analog VER-49009M, inhibited the proliferation of hepatic stellate cell line CFSC cells, and both of them induced G2 phase arrest in CFSC cells. Akt expression was decreased by the treatment of Hsp90 inhibitors in CFSC cells. Based on these findings, we propose that the inhibition of Hsp90 might be a rational approach in the prevention of liver fibrosis.

Pirfenidone inhibits carbon tetrachloride- and albumin complex-induced liver fibrosis in rodents by preventing activation of hepatic stellate cells

1. Pirfenidone (PFD; 5-methyl-1-phenyl-2(1H)-pyridone) is an effective and novel agent with antifibrotic and anti-inflammatory properties. In the present study, we investigated the antifibrotic effects of PFD on experimental liver fibrosis models in rodents and the possible underlying molecular mechanisms. 2. Liver fibrosis was induced by carbon tetrachloride (CCl(4)) in BALB/c mice. Pirfenidone (250 mg/kg) and silymarin (50 mg/kg) were given to different groups of rats by gastric gavage for 4 weeks. Pirfenidone significantly attenuated fibrosis severity, as determined by histopathological scores and hydroxyproline levels in liver tissue, by 49.8 and 44.9%, respectively, compared with the CCl(4)-treated group. The antifibrotic effects of PFD were significantly greater than those of silymarin, as indicated by a decrease of 23.5 and 24.8% in histopathological scores and hydroxyproline levels, respectively. 3. Liver fibrosis was also induced by albumin antigen-antibody complex in Wistar rats, which were then treated with the same doses of PFD and silymarin for 8 weeks. Pirfenidone significantly reduced the degree of fibrosis compared with CCl(4)-treated rats (by 45.0 and 51.0% as determined by histopathological scores and hydroxyproline levels in liver tissue, respectively). The antifibrotic effects of PFD were comparable to those of silymarin. 4. The effects of PFD on the expression of extracellular matrix-associated genes in human hepatic stellate cells (the LX-2 cell line) were measured by real-time quantitative polymerase chain reaction. LX-2 cells were treated with or without 100 micromol/L or 1 mmol/L PFD for 24 h. Pirfenidone significantly inhibited the expression of a-smooth muscle actin and Type I collagen in 8 ng/mL transforming growth factor-beta1- or 5% fetal bovine serum-activated LX-2 cells in a dose-dependent manner. 5. In conclusion, the results of the present study demonstrate that PFD is effective in ameliorating fibrogenesis induced by CCl(4) in mice and by the albumin complex in rats. These effects were mediated mainly via inhibition of the activation of hepatic stellate cells, as well as antifibrotic actions (i.e. inhibition of collagen synthesis) of PFD.

Protective effects of total flavonoids of Bidens bipinnata L. against carbon tetrachloride-induced liver fibrosis in rats

Bidens bipinnata L. is well known in China as a traditional Chinese medicine and has been used to treat hepatitis in clinics for many years. In a previous study we found that total flavonoids of Bidens bipinnata L. (TFB) had a protective effect against carbon tetrachloride (CCl4)-induced acute liver injury in mice. Now this study was designed to investigate its therapeutic effect against CCl4-induced liver fibrosis in rats and to determine, in part, its mechanism of action. The liver fibrosis model was established by subcutaneous injection of 50% CCl4 twice a week for 18 weeks. TFB (40, 80 and 160 mg kg(-1)) was administered by gastrogavage daily from the 9th week. The results showed that TFB (80 and 160 mg kg(-1)) treatment for 10 weeks significantly reduced the elevated liver index (liver weight/body weight) and spleen index (spleen weight/body weight), elevated levels of serum transaminases (alanine aminotransferase and aspartate aminotransferase), hyaluronic acid, type III procollagen and hepatic hydroxyproline. In addition, TFB markedly inhibited CCl4-induced lipid peroxidation and enhanced the activity of the antioxidant enzymes superoxide dismutase and glutathione peroxidase. Moreover, TFB (80 and 160 mg kg(-1)) treatment improved the morphologic changes of hepatic fibrosis induced by CCl4 and suppressed nuclear factor (NF)-kappaB, alpha-smooth muscle actin (SMA) protein expression and transforming growth factor (TGF)-beta1 gene expression in the liver of liver fibrosis of rats. In conclusion, TFB was able to ameliorate liver injury and protect rats from CCl4-induced liver fibrosis by suppressing oxidative stress. This process may be related to inhibiting the induction of NF-kappaB on hepatic stellate cell activation and the expression of TGF-beta1.

Systematic review: hepatic fibrosis - regression with therapy

BACKGROUND

Hepatic fibrosis occurs in response to chronic liver injury, regardless of the cause. An impressive amount of knowledge concerning the pathogenesis and treatment of liver fibrosis has emerged over the past few years. The hallmark of this event is the activation of the hepatic stellate cell. The latter event causes accumulation of extracellular matrix and formation of scar, leading to deterioration in hepatic function.

AIM

To assess chronic liver injury, many invasive and non-invasive methods have been suggested.

METHODS

Although transient elastography, image analysis of fractal geometry and fibrotest with actitest have been used in clinical practice, liver biopsy remains the recommended choice, especially when histological staging of fibrosis or response to treatment is needed.

CONCLUSIONS

The recent advances in anti-viral therapy have resulted in many reports on fibrosis and even on cirrhosis regression, especially early and in young people. A number of new agents have been suggested for the treatment of fibrosis, with promising results in animals; however, their efficacy in humans remains to be elucidated. The investigation of heterogeneity and plasticity of hepatic stellate cells is a topic of scientific interest and may result in improvements in patient management.

Functional hepatic recovery after xenotransplantation of cryopreserved fetal liver cells or soluble cell-factor administration in a cirrhotic rat model: are viable cells necessary?

BACKGROUND AND AIM

Chronic liver failure results in the decrease of the number of functioning hepatocytes. It dictates the necessity of using exogenous viable cells or/and agents that can stimulate hepatic regenerative processes. Fetal liver contains both hepatic and hematopoietic stem cells with high proliferative potential, which may replace damaged cells. Also, immature cells produce fetal-specific factors which may support the injured liver. Our aim was to test the ability of human fetal liver cells and cell-free fetal-specific factors of non-hepatic origin to stimulate recovery processes in an experimental model of carbon tetrachloride-induced cirrhosis in rats.

METHODS

Cirrhotic rats were intrasplenically injected with fetal liver cells (1 x 10(7) cells/0.3 mL medium) or cell-free fetal-specific factors (0.3 mL/1 mg protein). Control groups received medium alone. Serum indexes, hepatic functions, and morphology were evaluated for 15 days.

RESULT

Human fetal liver cell transplantation was shown to abrogate the mortality of cirrhotic animals, to improve serum markers, and to restore liver mitochondrial function and detoxification. Morphological patterns of liver recovery were observed by histology. In comparison, an injection of fetal-specific factors produced similar functional recovery, whilst a more limited liver regeneration was observed by histology.

CONCLUSIONS

The positive effects of fetal liver cell and cell-free fetal-specific factors in experimental cirrhosis may result from the presence of stage-specific factors activating hepatocellular repair.

Effect of bicyclol on the expression of hepatic immediate early genes, TGF-β1, TIMP1 and collagen in liver tissues of mice infected with Schistosoma japonicum

AIM: To study the therapeutic effect of bicyclol on schistosome-infected mice with liver fibrosis and its mechanism.

METHODS: Eighty mice were divided into four groups. Mice in the low-dose, high-dose and experimental control groups were infected with Schistosoma japonicum. After eight weeks, the low-dose and high-dose groups were treated with bicyclol at 60 mg (kg· d) and 120 mg (kg· d), respectively, for 8 weeks. The experimental control group received no treatment. The fourth group was a normal control group. HE staining, RT-PCR and immunohistochemistry were used to observe the pathological changes in liver tissues of mice, the expression levels of hepatic c-fos and c-jun mRNAs, and the levels of hepatic transforming growth factor β1 (TGF-β1), tissue inhibitor of metalloproteinase 1 (TIMP1), and types I and III collagen, before and after treatment.

RESULTS: Bicyclol treatment at a high dosage significantly relieved the degree of hepatic fibrosis compared with the experimental control group. The mRNA expression levels of c-fos and c-jun in liver tissue were significantly reduced in the high-dose group compared with the experimental control and low-dose groups (c-fos mRNA: 0.6511 ± 0.0551 vs 0.7844 ± 0.0852, 0.8072 ± 0.0923; c-jun mRNA: 0.6803 ± 0.0712 vs 0.7982 ± 0.0902, 0.8289 ± 0.094). The levels of hepatic TGF-β1, TIMP1 and types I and III collagen in the high-dose bicyclol treated group (integral light density: 0.1815 ± 0.0231, 0.2324 ± 0.0536, 0.1811 ± 0.0514, 0.1543 ± 0.0603) were significantly lower than those in the experimental control group (0.2139 ± 0.0134, 0.2648 ± 0.0361, 0.2140 ± 0.0271, 0.1862 ± 0.0217), but were still higher than those in the normal control group.

CONCLUSION: The effect of bicyclol on liver fibrosis due to Schistosoma japonicum infection depend on its dosage. The anti-fibrotic effect of high-dose bicyclol treatment may be due to its inhibition on the expression of immediate early genes, which may lead to reduced synthesis of TGFβ and TIMP1.

Modified synthetic siRNA targeting tissue inhibitor of metalloproteinase-2 inhibits hepatic fibrogenesis in rats

BACKGROUND/AIMS

Fibrosis occurs in most chronic liver injuries and results from changes in the balance between synthesis and degradation of extracellular matrix (ECM) components. Matrix metalloproteinases (MMPs) and their endogenous inhibitors (TIMPs) are known to regulate the ECM turnover. We investigate the effect of modified synthetic small interfering RNA (siRNA) targeting TIMP-2 in rat model of liver fibrosis.

METHODS

Rat hepatic fibrosis was induced by CCl4 for 8 weeks. After the 2-week CCl4 injection period, rats in the three siRNA groups simultaneously received a different dosage (0.05, 0.1 and 0.2 mg.kg(-1), respectively) of modified synthetic siRNA targeting TIMP-2 via the tail vein every 3 days for 6 weeks. The pathological changes in liver tissues were observed by light microscopy and transmission electron microscopy. Portal vein pressure and proliferating cell nuclear antigen were measured. Expression of TIMP-2, MMP-2, MT1-MMP, MMP-13, hepatocyte growth factor, collagen type I, collagen type III and alpha-SMA were evaluated by quantitative real-time polymerase chain reaction or Western blotting or gelatin zymography.

RESULTS

Modified synthetic siRNA targeting TIMP-2 induced a dose-dependent inhibition of the TIMP-2 expression in the rat model of liver fibrosis with a similar trend in MMP-2 and MT1-MMP, but an increase in MMP-13. Rats administered siRNA targeting TIMP-2 showed promotion of ECM degradation, reduction in activated hepatic stellate cells and enhancement of hepatocyte regeneration. Furthermore, portal hypertension was also ameliorated after treatment with siRNA targeting TIMP-2.

CONCLUSIONS

Knock-down of TIMP-2 expression attenuates CCl4-induced liver fibrosis and is a potential pharmacological target for gene therapy in liver fibrosis.

Inhibitory effects of saikosaponin-d on CCl4-induced hepatic fibrogenesis in rats

AIM: To investigate the suppressive effect of saikosaponin-d (SSd) on hepatic fibrosis in rats induced by CCl₄ injections in combination with alcohol and high fat, low protein feeding and its relationship with the expression of nuclear factor-κB (NF-κB), tumor necrosis factor-alpha (TNF-α) and interleukins-6 (IL-6).

METHODS: Hepatic fibrosis models were induced by subcutaneous injection of CCl₄ at a dosage of 3 mL/kg in rats. At the same time, rats in treatment groups were injected intraperitoneally with SSd at different doses (1.0, 1.5 and 2.0 mg/kg) once daily for 6 wk in combination with CCl₄, while the control group received olive oil instead of CCl₄. At the end of the experiment, rats were anesthetized and killed (except for 8 rats which died during the experiment; 2 from the model group, 3 in high-dose group, 1 in medium-dose group and 2 in low-dose group). Hematoxylin and eosin (HE) staining and Van Gieson staining were used to examine the changes in liver pathology. The levels of alanine aminotransferase (ALT), triglyeride (TG), albumin (ALB), globulin (GLB), hyaluronic acid (HA) and laminin (LN) in serum and the content of hydroxyproline (HYP) in liver were measured by biochemical examinations and radioimmuneoassay, respectively. In addition, the expression of TNF-α and IL-6 in liver homogenate was evaluated by enzyme-linked immunosorbent assay (ELISA) and the levels of NF-κBp65 and I-κBα in liver tissue were analyzed by Western blotting.

RESULTS: Both histological examination and Van Gieson staining demonstrated that SSd could attenuate the area and extent of necrosis and reduce the scores of liver fibrosis. Similarly, the levels of ALT, TG, GLB, HA, and LN in serum, and the contents of HYP, TNF-α and IL-6 in liver were all significantly increased in model group in comparison with those in control group. Whereas, the treatment with SSd markedly reduced all the above parameters compared with the model group, especially in the medium group (ALT: 412 ± 94.5 IU/L vs 113.76 ± 14.91 IU/L, TG: 0.95 ± 0.16 mmol/L vs 0.51 ± 0.06 mmol/L, GLB: 35.62 ± 3.28 g/L vs 24.82 ± 2.73 g/L, HA: 42.15 ± 8.25 ng/mL vs 19.83 ± 3.12 ng/mL, LN: 27.56 ± 4.21 ng/mL vs 13.78 ± 2.57 ng/mL, HYP: 27.32 ± 4.32 μg/mg vs 16.20 ± 3.12 μg/mg, TNF-α: 4.38 ± 0.76 ng/L vs 1.94 ± 0.27 ng/L, IL-6: 28.24 ± 6.37 pg/g vs 12.72 ± 5.26 pg/g, respectively, P < 0.01). SSd also decreased ALB in serum (28.49 ± 4.93 g/L vs 37.51 ± 3.17 g/L, P < 0.05). Moreover, the expression of NF-κB p65 in the liver of treated groups was lower than that in model groups while the expression of I-κBα was higher in treated group than in model group (P < 0.01). The expression of NF-κBp65 and TNF-α had a positive correlation with the level of HA in serum of rats after treatment with CCl₄ (r = 0.862, P < 0.01; r = 0.928, P < 0.01, respectively).

CONCLUSION: SSd attenuates CCl₄-induced hepatic fibrosis in rats, which may be related to its effects of hepato-protective and anti-inflammation properties, the down-regulation of liver TNF-α, IL-6 and NF-κBp65 expression and the increased I-κBα activity in liver.

Expression pattern of matrix metalloproteinases in alcohol- and thermally oxidized sunflower oil-induced toxicity: protective role of an aminothiazole derivative

The matrix metalloproteinases (MMPs) are a family of secreted and membrane-bound zinc endopeptidases. Collectively, these enzymes can degrade all of the components of the extracellular matrix including collagen, fibronectin, laminin, and basement membrane glycoproteins. Regulation in expression and activation of proteinases is one of the most important mechanisms in organ morphogenesis. Fibrosis is a dynamic pathological process with a net accumulation of extracellular matrix proteins. In the present communication, we have investigated the changes that occur in the activity of liver MMPs in normal and in pathological conditions. The activity of MMPs was increased in thermally oxidized sunflower oiland alcohol-treated groups, whereas the activity was decreased in the thermally oxidized oil + alcohol-fed group when compared with the normal control group. The activity was positively modulated when dendrodoine analogue [4-amino-5-benzoyl- 2(4-methoxyphenylamino)thiazole] was administered along with ethanol and thermally oxidized oil, which indicates the protective effect of this drug.

Gene expression profile analysis of spontaneous reversion of CCl4-induced hepatic fibrosis in rats

AIM: To screen the differentially expressed gene in the spontaneous reversion of hepatic fibrosis induced by carbon tetrachloride (CCl₄), and to reveal the gene expression profile in this process.

METHODS: Animal model of hepatic fibrosis with spontaneous reversion was created in SD rats by injection of carbon tetrachloride (CCl₄) for 8 weeks and then withdrawing for 6 weeks. The mRNA of liver tissues was extracted at different time spots in the process of reversion. Then cDNA microarray was used to screen the differentially expressed genes. Finally the products were subjected to hierarchical clustering and confirmed by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) of α-synuclein, A-raf, presenilin-2 and β-actin.

RESULTS: Hepatic fibrosis was progressively reversed after stopping injection of CCl₄. All together, there were 254 (21.59%) genes that changed at the transcription level. Meanwhile, 54, 85, 97 and 132 genes were identified differentially expressed in the 8^th, 10^th, 12^th and 14^th week, respectively. After confirmed by RT-PCR, the differentially expressed were associated with metabolic enzymes, ion channels, transcription factors, gastrointestinal hormones and their receptors, mitogen-activated protein kinase (MAPK) and PI3k/Akt signaling pathway.

CONCLUSION: The gene expression profile is significantly changed in the spontaneous recovery of CCl₄-induced hepatic fibrosis. Genes closely related to the spontaneous recovery are associated with metabolic enzymes, transporter/symporter proteins, gastrointestinal hormones/receptors, lipoprotein/fatty acid binding proteins, transcription factor/nuclear factors, and MAPK signal pathway.

Effect of Chinese drug compound Ganzhifu on liver fibrosis in rats

AIM: To investigate the effect of compound Ganzhifu on experimental hepatic fibrosis and its possible mechanism.

METHODS: Forty-five Wistar rats were randomly divided into four groups: normal (N) group, Ganzhifu (G) group, colchicine (C) group and model (M) group. All the rats, except those in N group, were given CCl₄ by subcutaneous injection and alcohol (10%) by oral administration to establish the model of hepatic fibrosis. At the same time, the rats in G, C or M group were treated through stomach irrigation with Ganzhifu, colchicine or saline, respectively. Blood was collected for the examination of liver function and serum fibrosis markers. Hydroxyproline (Hyp), malondial dehyde (MDA) content, and superoxide disumutase (SOD) activity were determined in liver tissues. HE, Masson and Gorden-Sweet staining were used to examine the pathological changes in liver tissue sections. Inflammation and fibrosis were evaluated by semi-quantitative scoring system (SSS). In addition, The expression of typeI, III, IV collagens was detected by immunohistochemistry.

RESULTS: Compared with that in M group, liver function was improved remarkably in G group, and there were significant decreases in the liver fibrosis markers (Hyp: 1.52±0.35 mg/g vs 1.12±0.29 mg/g, P<0.05; MDA: 16.3±6.0 mmol/g vs

8.8±2.1 mmol/g, P<0.01). However, the SOD activity was notably elevated (86.33±17.74 nkat/g vs 122.01±19.12 nkat/g, P<0.01). Less inflammation, lower degree of fibrosis and reduced content of typeI, III, IV collagens were observed in G group than in M group. No significant difference was found between the effects of Ganzhifu and colchicines against fibrosis.

CONCLUSION: Ganzhifu can protect liver from fibrosis and the mechanism may be related to its anti-oxidative effect.

Dynamic changes in the expression of matrix metalloproteinases and their inhibitors, TIMPs, during hepatic fibrosis induced by alcohol in rats

AIM: To determine the dynamic changes in the expression of matrix metalloproteinases (MMPs) and the endogenous tissue inhibitors of MMPs inhibitors (TIMPs) during hepatic fibrosis induced by alcohol.

METHODS: Male Sprague-Dawley rats were randomly divided into normal, 4 d, 2 wk, 4 wk, 9 wk and 11 wk groups, and the model rats were fed with a mixture of alcohol by gastric infusion at the designed time, respectively, then decollated and their livers were harvested for the examination of MMP-2, MMP-3, MMP-9, MMP-13, TIMP-1 and TIMP-2 by immunoh-istochemistry, zymograghy and Western blotting, respectively.

RESULTS: Normal rats had moderate expression of MMP-2, which was decreased in the model rats except in the 11 wk group, where MMP-2 expression slightly increased. MMP-3 had the similar changing pattern to MMP-2 despite weaker expression. MMP-9 expression decreased in the 4 d and 2 wk groups, rose in the 4 wk group, decreased again in the 9 wk group and returned to normal levels in the 11 wk group. MMP-13 expression decreased in the 4 d and 2 wk groups, and returned to normal levels in the 4 wk, 9 wk and 11 wk groups. TIMP-1 expression decreased in the 4 d and 2 wk groups, but sharply increased in the 4 wk group and sustained at a high level even after modeling was stopped for 2 wk. In normal rats TIMP-2 expression was strong. However, it decreased as soon as modeling began, and then gradually rose, but remained to a level lower than that in normal rats even after modeling was stopped for 2 wk.

CONCLUSION: MMP-2 may not always expresses at a high level during hepatic fibrosis. MMP-13 and MMP-3 are acutely affected by TIMP-1. In this model TIMP-1 is the most powerful factor imposed on capillarization and peri-sinusoidal fibrosis. TIMP-2 is the most effective regulator on the metabolism of type IV collagen located in the basement of sinus.

Pathological comparison of hepatic-fibrosis models induced by porcine serum and carbon tetrachloride in rats

AIM: To compare liver pathological changes between two different hepatic-fibrosis models induced by porcine serum and carbon tetrachloride in rats.

METHODS: Hepatic fibrosis was induced in rats by biweekly intraperitoneal injection of porcine serum (0.5 mL) or 400 mL/L carbon tetrachloride (2 mL/kg) for 7 weeks. Five rats were randomly selected from the survivals in each group. Liver tissue was removed, fixed, sliced and stained with hematoxylin and esosin for routine light-microscopy, Masson trichrome for collagen, Jame's double ammoniated siver solution for reticulin, and then subjected to semiquantitative evaluation by pathological image analyzer. Another portion of liver tissue was prepared for electron microscopy.

RESULTS: Liver tissue in rats receiving pig serum displayed narrow fibrotic sepatae including obvious collagen deposition and more mesenchymal constituents, and collagen was confined to the septae. Hepatocellular injury is rare. In contrast, in the livers from rats treated with CCl₄, the fibrotic septae were coarse, more cellular and diffuse. The parenchymal damage was more severe and extensive. The fatty metamorphosis of hepatocytes was evident. Semiquantitative analyses suggested that quantity of collagenic fibers and reticular fibers in CCl₄ group were significantly higher than those in porcine serum group.

CONCLUSION: Hepatic fibrosis in rats induced by CCl₄ is more severe than that induced by porcine serum.

Gene expression profiling of alcoholic liver disease in the baboon (Papio hamadryas) and human liver

The molecular pathogenesis of alcoholic liver disease (ALD) is not well understood. Gene expression profiling has the potential to identify new pathways and altered molecules in ALD. Gene expression profiles of ALD in a baboon model and humans were compared using DNA arrays. Reverse transcriptase-polymerase chain reaction and immunohistochemistry were used for downstream analysis of array results. cDNA array analysis revealed differential expression of several novel genes and pathways in addition to genes known to be involved in ALD pathogenesis. Overall gene expression profiles were similar in both species, with a majority of genes involved with fibrogenesis and xenobiotic metabolism, as well as inflammation, oxidant stress, and cell signaling. Genes associated with stellate cell activation (collagens, matrix metalloproteinases, tissue inhibitors of matrix metalloproteinase) were up-regulated in humans. Decreased expression of several metallothioneins was unexpected. Fourteen molecules related to the annexin family were up-regulated, including annexin A1 and A2. Immunofluorescence revealed a marked overexpression of annexin A2 in proliferating bile duct cells, hepatocyte cell surface, and selective co-localization with CD14-positive cells in human ALD. The gene expression profile of ALD is dominated by alcohol metabolism and inflammation and differs from other liver diseases. Annexins may play a role in the progression of fibrosis in ALD.

Diagnostic value of platelet derived growth factor-BB, transforming growth factor-β1, matrix metalloproteinase-1, and tissue inhibitor of matrix metalloproteinase-1 in serum and peripheral blood mononuclear cells for hepatic fibrosis

AIM: Noninvasive diagnosis of hepatic fibrosis has become the focus because of the limited biopsy, especially in the surveillance of treatment and in screening hepatic fibrosis. Recently, regulatory elements involved in liver fibrosis, such as platelet derived growth factor-BB (PDGF-BB), transforming growth factor-β₁ (TGF-β₁), matrix metalloproteinase-1 (MMP-1), and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), have been studied extensively. To determine whether these factors or enzymes could be used as the indices for the diagnosis of hepatic fibrosis, we investigated them by means of receiver operating characteristic (ROC) curve.

METHODS: Serum samples from sixty patients with chronic viral hepatitis B and twenty healthy blood donors were assayed to determine the level of PDGF-BB, TGF-β₁, MMP-1, and TIMP-1 with ELISA, and HA, PCIII, C-IV, and LN level with RIA. The message RNA (mRNA) expression of TIMP-1 and MMP-1 in peripheral blood mononuclear cells (PBMCs) was detected by RT-PCR and Northern blot hybridization. Liver biopsy was performed in all patients. The biopsy samples were histopathologically examined. The trial was double-blind controlled.

RESULTS: The serum level of PDGF-BB, TIMP-1, the ratio of TIMP-1 and MMP-1 (TIMP-1/MMP-1), mRNA expression of TIMP-1 (TIMP-1mRNA), and the ratio of TIMP-1mRNA and MMP-1mRNA (TIMP-1mRNA/MMP-1mRNA) in patients was significantly higher than those in the healthy blood donors (t = 2.514-11.435, P = 0.000-0.016). The serum level of PDGF-BB, TIMP-1, TIMP-1/MMP-1, and TIMP-1mRNA was positively correlated with fibrosis stage and inflammation grade (r = 0.239-0.565, P = 0.000-0.033), while the serum level of MMP-1 was negatively correlated with fibrosis stage and inflammation grade, and TIMP-1mRNA/MMP-1mRNA was positively correlated with inflammation grade. Through the analysis by ROC curve, serum PDGF-BB was the most valuable marker, and its sensitivity was the highest among the nine indices. The markers with the highest specificity were TIMP-1mRNA and TIMP-1mRNA/MMP-1mRNA in PBMCs. The area under the curve (AUC) of PDGF-BB, TIMP-1mRNA, TIMP-1mRNA/MMP-1mRNA, TIMP-1/MMP-1, HA, PCIII, TIMP-1, C-IV, and LN was 0.985, 0.876, 0.792, 0.748, 0.728, 0.727, 0.726, 0.583, and 0.463, respectively. The sensitivity and the specificity in the parallel test was 99.0% and 95.0% when serum PDGF-BB, TIMP-1mRNA and TIMP-1mRNA/MMP-1mRNA was detected simultaneously.

CONCLUSION: Serum level of PDGF-BB, TIMP-1mRNA, TIMP-1mRNA/MMP-1mRNA in PBMCs, and serum level of TIMP-1 and TIMP-1/MMP-1 can be used as the indices for the diagnosis of hepatic fibrosis, but the former three are more useful. The combination of serum PDGF-BB, TIMP-1mRNA and TIMP-1mRNA/MMP-1mRNA in PBMCs is even more efficient in screening liver fibrosis.

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Effect of Oxymatrine on experimental liver fibrosis

AIM: To study the effect of Oxymatrine on liver fibrosis in immunogenic liver fibrosis rat model.

METHODS: Rat liver fibrosis model was induced by human serum albumin (HSA), 60 Wistar rats were randomly divided into 5 groups, control group without any treatment, liver fibrosis model group, oxymatrine preventive group, oxymatrine therapeutic group, and cochicine therapeutic group. The pathological changes of liver were observed by HE and Von-Gieson staining. The expressions of mRNA and proteins of collagen I/III in liver were determined by in situ hybridization and immunohistochemistry.

RESULTS: The liver fibrosis degree and level of mRNA and proteins of collagen I/III in the liver were significantly reduced in the decreasing order in oxymatrine preventive group, oxymatrine therapeutic group, and cochicine therapeutic group.

CONCLUSION: Oxymatrine may inhibit hepatic inflammation and hepatic synthesis of collagen I/III, and thus prevent and inhibit hepatic fibrosis.

Effect of Chinese herb Shuangjiawuling on expression of TIMPs in rat with liver fibrosis

AIM: To explore the effect of Chinese herb Shuangjiawuling in preventing hepatic fibrosis in rat with liver fibrosis.

METHODS: Rat immunogenic liver fibrosis model was induced by administration human serum albumin (HSA 200 g/L) intravenously, 80 rats were randomly divided into 5 groups. Shuangjiawuling was taken orally simultaneously with (group A), immediately after (group B), or 3 months after (group C) administration of HAS intravenously. Colchine tablets were taken orally with the administration of HAS (group D), normal rats were used as control (Group E). The pathological changes of liver tissue were observed by HE and Von-Gieson staining. The hepatic mRNA and protein of TIMP-1 and TIMP-2 were analyzed by in site hybridization and immunohistochemistry.

RESULTS: Hepatic fibrosis developed gradually and became obviously on the third month after administration of HAS. And strong expressions of TIMP-1 and TIMP-2 were observed, however, its expression and hepatic fibrosis were reduced dramatically following administration of Shuangjiawuling and colchine tablets. The effect of Shuangjiawuling in preventing fibrosis was superior to that of colchine tablets (P<0.05), and its effect in group A, B, and C decreased in order.

CONCLUSION: Chinese herb Shuangjiawuling can inhibit the development of hepatic fibrosis and the expression of TIMPs, and promoted the effect of the degradation of the extracellular matrix.

Effects of pentoxifylline on the hepatic content of TGF-β1 and collagen in Schistosomiasis japonica mice with liver fibrosis

AIM: To study the effects of pentoxifylline (PTX) on the content of hepatic TGF-β1, type I and type III collagen in schistosomiasis japonica mice with liver fibrosis and its mechanism of anti-fibrosis.

METHODS: Forty mice with schistosomiasis were divided into four groups: one group as control without any treatment, other three were treated with Praziquantel 500 mg/(kg·d)for 2 d, high dose PTX 360 mg/(kg·d) for 8 wk, and low dose PTX 180 mg/(kg·d) for 8 wk respectively. Immunohistochemical technique and multimedia color pathographic analysis system were applied to observe the content change of hepatic TGF-β1, type I and type III collagen in schistosomiasis japonica mice with liver fibrosis before and after PTX treatment.

RESULTS: Effects of PTX on the content change of hepatic TGF-β1, type I and type III collagen in schistosomiasis japonica mice with liver fibrosis were related to the dosage of PTX, high dose PTX treated group could significantly reduce the content of TGF-β1 (0.709 ± 0.111), type I (0.644 ± 0.108) and type III (0.654 ± 0.152) collagen compared with those of control group (0.883 ± 0.140, 0.771 ± 0.156, 0.822 ± 0.129) with statistical significance (P < 0.05). Low dose PTX could also reduce the hepatic content of TGF-β1 (0.752 ± 0.152), type I (0.733 ± 0.117) and type III (0.788 ± 0.147) collagen, but without statistical significance (P > 0.05). Both high dose and low dose PTX groups have significant differences on the content of TGF-β1, type I and type III collagen (P < 0.05, P < 0.05, P < 0.01, respectively).

CONCLUSION: High dose of PTX treatment could reduce the content of hepatic TGF-β1, type I and type III collagen significantly in schistosomiasis japonica mice with liver fibrosis, and thus plays its role of antifibrosis.