Dual expression of matrix metalloproteinase-2 and membrane-type 1-matrix metalloproteinase in fibrotic human livers

Fibrosis and Hepatocarcinogenesis: Role of Gene-Environment Interactions in Liver Disease Progression

The liver is a complex organ that performs vital functions in the body. Despite its extraordinary regenerative capacity compared to other organs, exposure to chemical, infectious, metabolic and immunologic insults and toxins renders the liver vulnerable to inflammation, degeneration and fibrosis. Abnormal wound healing response mediated by aberrant signaling pathways causes chronic activation of hepatic stellate cells (HSCs) and excessive accumulation of extracellular matrix (ECM), leading to hepatic fibrosis and cirrhosis. Fibrosis plays a key role in liver carcinogenesis. Once thought to be irreversible, recent clinical studies show that hepatic fibrosis can be reversed, even in the advanced stage. Experimental evidence shows that removal of the insult or injury can inactivate HSCs and reduce the inflammatory response, eventually leading to activation of fibrolysis and degradation of ECM. Thus, it is critical to understand the role of gene-environment interactions in the context of liver fibrosis progression and regression in order to identify specific therapeutic targets for optimized treatment to induce fibrosis regression, prevent HCC development and, ultimately, improve the clinical outcome.

Advances in Noninvasive Molecular Imaging Probes for Liver Fibrosis Diagnosis

Liver fibrosis is a wound-healing response to chronic liver injury, which may lead to cirrhosis and cancer. Early-stage fibrosis is reversible, and it is difficult to precisely diagnose with conventional imaging modalities such as magnetic resonance imaging, positron emission tomography, single-photon emission computed tomography, and ultrasound imaging. In contrast, probe-assisted molecular imaging offers a promising noninvasive approach to visualize early fibrosis changes in vivo, thus facilitating early diagnosis and staging liver fibrosis, and even monitoring of the treatment response. Here, the most recent progress in molecular imaging technologies for liver fibrosis is updated. We start by illustrating pathogenesis for liver fibrosis, which includes capillarization of liver sinusoidal endothelial cells, cellular and molecular processes involved in inflammation and fibrogenesis, as well as processes of collagen synthesis, oxidation, and cross-linking. Furthermore, the biological targets used in molecular imaging of liver fibrosis are summarized, which are composed of receptors on hepatic stellate cells, macrophages, and even liver collagen. Notably, the focus is on insights into the advances in imaging modalities developed for liver fibrosis diagnosis and the update in the corresponding contrast agents. In addition, challenges and opportunities for future research and clinical translation of the molecular imaging modalities and the contrast agents are pointed out. We hope that this review would serve as a guide for scientists and students who are interested in liver fibrosis imaging and treatment, and as well expedite the translation of molecular imaging technologies from bench to bedside.

The Role of Macrophage Inhibitory Factor in TAA-Induced Liver Fibrosis in Mice: Modulatory Effects of Betaine

Macrophage inhibitory factor (MIF) is a multipotent cytokine, involved in the inflammatory response to infections or injuries. This study investigates the role of MIF in liver fibrosis and the modulating effect of betaine on MIF in thioacetamide (TAA)-induced liver fibrosis. The wild-type and knockout MIF-/- C57BL/6 mice were divided into the following groups: control; Bet group, which received betaine; MIF-/-; MIF-/-+Bet; TAA group, which received TAA; TAA+Bet; MIF-/-+TAA; and MIF-/-+TAA+Bet group. After eight weeks of treatment, liver tissue was collected for further analysis. The results revealed that TAA-treated MIF-deficient mice had elevated levels of hepatic TGF-β1 and PDGF-BB, as well as MMP-2, MMP-9, and TIMP-1 compared to TAA-treated wild-type mice. However, the administration of betaine to TAA-treated MIF-deficient mice reduced hepatic TGF-β1 and PDGF-BB levels and also the relative activities of MMP-2, MMP-9 and TIMP-1, albeit less effectively than in TAA-treated mice without MIF deficiency. Furthermore, the antifibrogenic effect of MIF was demonstrated by an increase in MMP2/TIMP1 and MMP9/TIMP1 ratios. The changes in the hepatic levels of fibrogenic factors were confirmed by a histological examination of liver tissue. Overall, the dual nature of MIF highlights its involvement in the progression of liver fibrosis. Its prooxidant and proinflammatory effects may exacerbate tissue damage and inflammation initially, but its antifibrogenic activity suggests a potential protective role against fibrosis development. The study showed that betaine modulates the antifibrogenic effects of MIF in TAA-induced liver fibrosis, by decreasing TGF-β1, PDGF-BB, MMP-2, MMP-9, TIMP-1, and the deposition of ECM (Coll1 and Coll3) in the liver.

Concentration-Dependent Attenuation of Pro-Fibrotic Responses after Cannabigerol Exposure in Primary Rat Hepatocytes Cultured in Palmitate and Fructose Media

Hepatic fibrosis is a consequence of liver injuries, in which the overproduction and progressive accumulation of extracellular matrix (ECM) components with the simultaneous failure of matrix turnover mechanisms are observed. The aim of this study was to investigate the concentration-dependent influence of cannabigerol (CBG, Cannabis sativa L. component) on ECM composition with respect to transforming growth factor beta 1 (TGF-β1) changes in primary hepatocytes with fibrotic changes induced by palmitate and fructose media. Cells were isolated from male Wistar rats' livers in accordance with the two-step collagenase perfusion technique. This was followed by hepatocytes incubation with the presence or absence of palmitate with fructose and/or cannabigerol (at concentrations of 1, 5, 10, 15, 25, 30 µM) for 48 h. The expression of ECM mRNA genes and proteins was determined using PCR and Western blot, respectively, whereas media ECM level was evaluated using ELISA. Our results indicated that selected low concentrations of CBG caused a reduction in TGF-β1 mRNA expression and secretion into media. Hepatocyte exposure to cannabigerol at low concentrations attenuated collagen 1 and 3 deposition. The protein and/or mRNA expressions and MMP-2 and MMP-9 secretion were augmented using CBG. Considering the mentioned results, low concentrations of cannabigerol treatment might expedite fibrosis regression and promote regeneration.

Liver resection is associated with good outcomes for hepatocellular carcinoma patients beyond the Barcelona Clinic Liver Cancer criteria: A multicenter study with the Hiroshima Surgical study group of Clinical Oncology

BACKGROUND

Liver resection for hepatocellular carcinoma beyond the Barcelona Clinic Liver Cancer criteria remains controversial. Strict candidate selection is crucial to achieve optimal results in this population. This study explored postoperative outcomes and developed a preoperative predictive formula to identify patients most likely to benefit from liver resection.

METHODS

In total, 382 patients who underwent liver resection for hepatocellular carcinoma beyond the Barcelona Clinic Liver Cancer resection criteria between 2000 and 2017 were identified from a multicenter database with the Hiroshima Surgical study group of Clinical Oncology. An overall survival prediction model was developed, and patients were classified by risk status.

RESULTS

The 5-year overall survival after curative resection was 50.0%. Overall survival multivariate analysis identified that a high a-fetoprotein level, macrovascular invasion, and high total tumor burden were independent prognostic risk factors; these factors were used to formulate risk scores. Patients were divided into low-, moderate-, and high-risk groups; the 5-year overall survival was 65.7%, 49.5%, and 17.0% (P < .001), and the 5-year recurrence-free survival was 31.3%, 26.2%, and 0%, respectively (P < .001). The model performance was good (C-index, 0.76). Both the early and extrahepatic recurrence increased with higher risk score.

CONCLUSION

The prognosis of patients with hepatocellular carcinoma beyond the Barcelona Clinic Liver Cancer resection criteria depended on a high a-fetoprotein level, macrovascular invasion, and high total tumor burden, and risk scores based on these factors stratified the prognoses. Liver resection should be considered in patients with hepatocellular carcinoma beyond the Barcelona Clinic Liver Cancer criteria with a low or moderate-risk score.

The hepatoprotective effect of silibinin after hepatic ischemia/reperfusion in a rat model is confirmed by immunohistochemistry and qRT-PCR

OBJECTIVES

We investigated the positive effect of silibinin after IV administration as silibinin-hydroxypropyl-β-cyclodextrin lyophilized product, by measuring gene expression and liver tissue protein levels of tumor necrosis factor-α, interleukin-6, monocyte chemoattractant protein-1, matrix metalloproteinases matrix metalloproteinases and tissue inhibitor of matrix metalloproteinases-2.

METHODS

63 Wistar rats of age 13.24±4.40 weeks underwent ischemia/reperfusion (I/R) injury of the liver. The animals were randomized into three groups: Sham (S; n = 7); Control (C; n-28); silibinin (Si; n-28). The C and Si groups underwent 45 min ischemia. Si received silibinin-hydroxypropyl-β-cyclodextrin intravenously immediately before reperfusion at a dose of 5 mg/kg. Both groups were further divided into 4 subgroups, based on euthanasia time (i.e., 60, 120, 180 and 240 min).

KEY FINDINGS

qRT-PCR results confirmed the statistically significant reduction of the expression of the pro-inflammatory factors at 240 min after I/R injury (tumor necrosis factor-α: P < 0.05; MCR1: P < 0.05) and matrix metalloproteinases (matrix metalloproteinases 2: P < 0.05; matrix metalloproteinases 3: P < 0.05) and the increase of tissue inhibitor of matrix metalloproteinases-2 in liver tissue in the Si group. Moreover, results of immunohistochemistry levels confirmed that at 240 min pro-inflammatory factors (tumor necrosis factor-α: P < 0.05; MCR1: P < 0.05) and matrix metalloproteinases ( matrix metalloproteinases 2: P < 0.05; matrix metalloproteinases 3: P < 0.05) had a statistically significantly lower expression in the Si group while tissue inhibitor of matrix metalloproteinases-2 had a higher expression.

CONCLUSIONS

Silibinin may have a beneficial effect on the protection of the liver.

Production and activity of matrix metalloproteinases during liver fibrosis progression of chronic hepatitis C patients

BACKGROUND

Matrix metalloproteinases (MMPs) participate in the degradation of extracellular matrix compounds, maintaining the homeostasis between fibrogenesis and fibrolytic processes in the liver. However, there are few studies on the regulation of liver MMPs in fibrosis progression in humans.

AIM

To assess the production activity and regulation of matrix metalloproteinases in liver fibrosis stages in chronic hepatitis C (CHC).

METHODS

A prospective, cross-sectional, multicenter study was conducted. CHC patients were categorized in fibrosis grades through FibroTest^®and/or FibroScan^®. Serum MMP-2, -7, and -9 were determined by western blot and multiplex suspension array assays. Differences were validated by the Kruskal-Wallis and Mann-Whitney U tests. The Spearman correlation coefficient and area under the receiver operating characteristic curve were calculated. Collagenolytic and gelatinase activity was determined through the Azocoll substrate and zymogram test, whereas tissue inhibitor of metalloproteinase-1 production was determined by dot blot assays.

RESULTS

Serum concentrations of the MMPs evaluated were higher in CHC patients than in healthy subjects. MMP-7 distinguished early and advanced stages, with a correlation of 0.32 (P < 0.001), and the area under the receiver operating characteristic displayed moderate sensitivity and specificity for MMP-7 in F4 (area under the receiver operating characteristic, 0.705; 95% confidence interval: 0.605-0.805; P < 0.001). Collagenolytic activity was detected at F0 and F1, whereas gelatinase activity was not detected at any fibrosis stage. Tissue inhibitor of metalloproteinase-1 determination showed upregulation in F0 and F1 but downregulation in F2 (P < 0.001).

CONCLUSION

High concentrations of inactive MMPs were present in the serum of CHC patients, reflecting the impossibility to restrain liver fibrosis progression. MMPs could be good diagnostic candidates and therapeutic targets for improving novel strategies to reverse liver fibrosis in CHC.

Integrating Network Pharmacology and Experimental Validation to Investigate the Effects and Mechanism of Astragalus Flavonoids Against Hepatic Fibrosis

Hepatic fibrosis (HF) represents the excessive wound healing where an excess amount of connective tissues is formed within the liver, finally resulting in cirrhosis or even hepatocellular carcinoma (HCC). Therefore, it is significant to discover the efficient agents and components to treat HF, thus restraining the further progression of hepatopathy. Astragalus membranaceus (Fisch.) Bunge [also called Astragali Radix (AR)] is a famous herb in traditional Chinese medicine (TCM), which possesses a variety of biological activities and exerts good therapeutic effects in the treatment of HF. Flavonoids account for the major active ingredients related to the AR pharmacological effects. Total AR flavonoids have been proved to exert inhibitory effects on hepatic fibrosis. This study aimed to further undertake network pharmacology analysis coupled with experimental validation and molecular docking to investigate the effects and mechanism of multiple flavonoid components from AR against liver fibrosis. The results of the network pharmacology analysis showed that the flavonoids from AR exerted their pharmacological effects against liver fibrosis by modulating multiple targets and pathways. The experimental validation data showed that the flavonoids from AR were able to suppress transforming growth factor beta 1 (TGF-β1)-mediated activation of hepatic stellate cells (HSCs) and reduce extracellular matrix deposition in HSC-T6 cells via regulating the nuclear factor kappa B (NF-κB) signal transduction pathway. The results of the molecular docking study further showed that the flavonoids had a strong binding affinity for IκB kinase (IKKβ) after docking into the crystal structure. The above results indicated that, flavonoids possibly exerted the anti-inflammatory effect on treating HF by mediating inflammatory signaling pathways. The potential mechanism of these flavonoids against liver fibrosis may be related to suppression of the NF-κB pathway through effective inhibition of IKKβ. This study not only provides a scientific basis for clarifying the effects and mechanism of AR flavonoids against liver fibrosis but also suggests a novel promising therapeutic strategy for the treatment of liver fibrosis.

Transcriptional regulation of alcohol induced liver fibrosis in a translational porcine hepatocellular carcinoma model

Hepatocellular carcinoma (HCC) is the 5th most common and 2nd deadliest cancer worldwide. HCC risk factors include alcohol induced liver cirrhosis, which prompts hepatic inflammation, cell necrosis, and fibrosis deposition. As 25% of HCC cases are associated with alcohol induced liver disease, understanding the effects of the cirrhotic liver microenvironment on HCC tumor biology and therapeutic responses are critical. This study utilized the Oncopig Cancer Model-a transgenic pig model that recapitulates human HCC through induced expression of KRAS^G12D and TP53^R167H driver mutations-to investigate the molecular mechanisms underlying alcohol induced liver disease. Oncopigs (n = 5) underwent fibrosis induction via infusion of ethanol and ethiodized oil (1:3 v/v dosed at 0.75 mL/kg) into the hepatic arterial circulation. Eight-weeks post induction, liver tissue samples from fibrotic and age-matched control (n = 5) Oncopigs were collected for histological evaluation and transcriptional profiling. Increased hepatic inflammation and fibrosis was observed in fibrotic Oncopigs via pathological assessment. Transcriptional profiling (RNA-seq) resulted in the identification of 4387 differentially expressed genes between Oncopig fibrotic and control livers. GO term enrichment analysis identified pathway alterations associated with cirrhosis progression in humans, including cell proliferation, angiogenesis, extracellular matrix deposition, and oxidation-reduction. Key alterations include activation of hepatic stellate cells, increased matrix metalloproteinase production, and altered expression of ABC and SLC transporter genes involved in transport of anticancer drugs.These results demonstrate Oncopig liver fibrosis recapitulates transcriptional hallmarks of human cirrhosis, making the Oncopig an ideal model for studying the effects of the cirrhotic liver microenvironment on HCC tumor biology and therapeutic response.

Induction of synthesis of matrix metalloproteinases by interleukin-6; evidence for hepatic regeneration following hemi-hepatectomy

Aim of the study

Interleukin-6 (IL-6) can play a role in hepatic regeneration through many mechanisms, one of which is the induction of synthesis of matrix metalloproteinases (MMPs). The aim of the study is to focus on the significance and role of MMPs in the regenerative process to reveal the correlation between IL-6 and MMPs in rats following partial hepatectomy.

Material and methods

Following hemi-hepatectomy, eighty male rats were divided into a control group and a group treated with IL-6 35 µg/100 gm body weight according to a lethality study. The blood samples were drawn from all animal groups for MMP-9 serum level assessment. For the quantitative determination of MMP-9 an enzyme-linked immunosorbent assay (ELISA) was used (Cytoimmune Science Inc., MD) through the quantitative sandwich immunosorbent assay technique. A monoclonal antibody for MMP-9 was pre-coated onto microplate standards. After washing away the unbound substances, an enzyme-linked polyclonal antibody specific for cytokine was added to the wells and color developed in proportion to the amount of total cytokine (pro and/or active) bound in the initial step. The color development was stopped and the intensity of the color was measured.

Results

The liver regeneration rate (%) was significantly higher in the group of rats treated with IL-6 (median value was 49.55% vs. 33.20%), p < 0.001. The MMPs’ serum level was significantly higher in the group of rats with resection and treatment (median value was 8.01).

Conclusions

These results give evidence for the vital role of MMPs in the process of hepatic regeneration, the level of which, in turn, has a close relationship with the level of IL-6. MMPs have diverse effects in promoting angiogenesis, remodeling of extracellular matrix and endothelial cell proliferation.

Matrix Metalloproteinases as Potential Biomarkers and Therapeutic Targets in Liver Diseases

Chronic liver diseases, characterized by an excessive accumulation of extracellular matrix (ECM) resulting in scar tissue formation, are a growing health problem causing increasing morbidity and mortality worldwide. Currently, therapeutic options for tissue fibrosis are severely limited, and organ transplantation is the only treatment for the end-stage liver diseases. During liver damage, injured hepatocytes release proinflammatory factors resulting in the recruitment and activation of immune cells that activate quiescent hepatic stellate cells (HSCs). Upon activation, HSCs transdifferentiate into highly proliferative, migratory, contractile and ECM-producing myofibroblasts. The disrupted balance between ECM deposition and degradation leads to the formation of scar tissue referred to as fibrosis. This balance can be restored either by reducing ECM deposition (by inhibition of HSCs activation and proliferation) or enhancing ECM degradation (by increased expression of matrix metalloproteinases (MMPs)). MMPs play an important role in ECM remodeling and represent an interesting target for therapeutic drug discovery. In this review, we present the current knowledge about ECM remodeling and role of the different MMPs in liver diseases. MMP expression patterns in different stages of liver diseases have also been reviewed to determine their role as biomarkers. Finally, we highlight MMPs as promising therapeutic targets for the resolution of liver diseases.

Pnpla3 silencing with antisense oligonucleotides ameliorates nonalcoholic steatohepatitis and fibrosis in Pnpla3 I148M knock-in mice

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) is becoming a leading cause of advanced chronic liver disease. The progression of NAFLD, including nonalcoholic steatohepatitis (NASH), has a strong genetic component, and the most robust contributor is the patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 encoding the 148M protein sequence variant. We hypothesized that suppressing the expression of the PNPLA3 148M mutant protein would exert a beneficial effect on the entire spectrum of NAFLD.

METHODS

We examined the effects of liver-targeted GalNAc3-conjugated antisense oligonucleotide (ASO)-mediated silencing of Pnpla3 in a knock-in mouse model in which we introduced the human PNPLA3 I148M mutation.

RESULTS

ASO-mediated silencing of Pnpla3 reduced liver steatosis (p = 0.038) in homozygous Pnpla3 148M/M knock-in mutant mice but not in wild-type littermates fed a steatogenic high-sucrose diet. In mice fed a NASH-inducing diet, ASO-mediated silencing of Pnpla3 reduced liver steatosis score and NAFLD activity score independent of the Pnpla3 genotype, while reductions in liver inflammation score (p = 0.018) and fibrosis stage (p = 0.031) were observed only in the Pnpla3 knock-in 148M/M mutant mice. These responses were accompanied by reduced liver levels of Mcp1 (p = 0.026) and Timp2 (p = 0.007) specifically in the mutant knock-in mice. This may reduce levels of chemokine attracting inflammatory cells and increase the collagenolytic activity during tissue regeneration.

CONCLUSION

This study provides the first evidence that a Pnpla3 ASO therapy can improve all features of NAFLD, including liver fibrosis, and suppress the expression of a strong innate genetic risk factor, Pnpla3 148M, which may open up a precision medicine approach in NASH.

Extracellular matrix components indicate remodelling activity in different fibrosis stages of human non-alcoholic fatty liver disease

AIMS

The composition of several important extracellular matrix components (ECM) has not yet been elucidated in human non-alcoholic fatty liver disease (NAFLD). We aim to investigate the proportion of hepatic stellate cells (HSCs) and activity of matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) in human NAFLD liver tissue with respect to severity of inflammation and fibrosis.

METHODS AND RESULTS

Histopathological features were quantified by NAFLD activity score and grading assignment. The collagen proportionate area (CPA) was measured. Slides were stained with alpha-smooth muscle actin (α-SMA), as a marker of activated HSCs, and α-SMA was quantified digitally. Zymography was performed to measure the proteolytic activity of MMP-2 and MMP-9. TIMP-1 and TIMP-2 protein concentration was measured with enzyme-linked immunosorbent assay (ELISA). α-SMA was higher in severe fibrosis (6.3%, interquartile range 2.9-13.1) than mild and no fibrosis (median 1.1 and 0.9%, P < 0.001) and correlated strongly with CPA (Rs = 0.870, P < 0.001). ProMMP-2 activity in severe (4.1%, IQR 2.6-16.2) and mild fibrosis (2.7%, IQR 1.9-3.9) was higher than in no fibrosis (1.5%, (IQR 0.95-2.1); P = 0.001 and P = 0.046) and showed a moderate positive correlation with CPA (Rs = 0.495, P = 0.001). TIMP-1 and TIMP-2 were significantly higher in severe fibrosis than mild or no fibrosis. Both showed moderate correlation with CPA (TIMP-1: Rs = 0.471, P = 0.002 and TIMP-2: Rs = 0.325, P = 0.036). MMP-9 correlated as the only ECM component to inflammation severity.

CONCLUSIONS

Advanced human NAFLD-fibrosis has a distinct ECM composition with increased HSCs and increased TIMP inhibition, but there is also ongoing remodelling activity of MMP-2.

Emerging insights into the role of matrix metalloproteases as therapeutic targets in fibrosis

Fibrosis is the extensive accumulation and buildup of extracellular matrix components, especially fibrillar collagens, during wound healing in response to tissue injury. During all individual stages of fibrosis ECM proteases, mainly matrix metalloproteinases, have diverse roles. The functional role of MMPs and their endogenous inhibitors are differentiated among their family members, and according to the different stages of fibrosis. MMPs levels are elevated in several inflammatory and non-inflammatory fibrotic tissues contributing to the development, progression or resolution of the disease, whereas in other tissues their expression levels can be diminished or be stable to the baseline. The biological roles of MMPs during fibrosis are not fully resolved, but they seem to differ according the specific member of the family, the affected tissue and the stage of the fibrotic response. Remarkably, some members of the family exhibit profibrotic actions while other function as antifibrotic molecules. Diverse animal models indicate that MMPs are contributing in processes related to immunity, tissue repair and ECM turnover, providing significant impact on mechanisms related to fibrosis. For that purpose, these proteases are considered as pharmacological targets and new biological drugs have been developed in order to treat fibrosis.

Matrix metalloproteinases and liver fibrosis (translational aspects)

Liver fibrosis, a reversible wound-healing response to chronic cellular injury, reflects a balance between liver repair and progressive substitution of the liver parenchyma by scar tissue. Complex mechanisms that underlie liver fibrogenesis are summarized to provide the basis for generating targeted therapies to reverse fibrogenesis and improve the outcomes of patients with chronic liver disease. This minireview presents some pathophysiological aspects of liver fibrosis as a dynamic process and elucidates matrix metalloproteinases (MMPs) and their role within as well as beyond matrix degradation. Open questions remain, whether inhibition of fibrogenesis or induction of fibrolysis is the key mechanism to resolve fibrosis. And a point of principle might be whether regeneration of liver cirrhosis is possible. Will we ever cure fibrosis?

Chemotherapy can promote liver metastasis by enhancing metastatic niche formation in mice

BACKGROUND

Some chemotherapeutic agents have been reported to promote lung metastasis. However, there have been no reports regarding chemotherapy-induced liver metastasis. We hypothesized that chemotherapy might also enhance liver metastasis. The present study aimed to create a chemotherapy-enhanced liver metastasis mouse model and investigate its mechanism.

MATERIALS AND METHODS

Mice were pretreated with cisplatin, vincristine, or saline by intraperitoneal injection. Next, B16F10 mouse melanoma cells and BE(2)-C human neuroblastoma cells were injected into the spleens of C57BL/6 and BALB/c nu/nu mice, respectively, to induce experimental liver metastasis, and the number of liver nodules was determined. We also analyzed the effect of chemotherapy on changes of the liver tissue regarding representative metastasis-promoting factors using real-time quantitative polymerase chain reaction and immunohistochemical and histological analysis.

RESULTS

Cisplatin increased the number of nodules by 4.7-fold in the B16F10 liver metastasis model. Vincristine increased the number of nodules by 3.8-fold in the BE(2)-C liver metastasis model. Cisplatin increased mRNA levels of matrix-metalloproteinase (MMP)-2 and periostin, while vincristine increased MMP-9 and S100A8/9 levels in liver tissues. Cisplatin induced fibrosis, whereas vincristine induced neutrophil recruitment in liver tissues according to histological and immunohistochemical analysis.

CONCLUSIONS

We concluded that cisplatin or vincristine could enhance liver metastasis of mouse melanoma cells or human neuroblastoma cells, respectively. In addition, the mRNA expression of MMP-2 and periostin, or MMP-9 and S100A8/9 is increased by cisplatin or vincristine pretreatment, possibly resulting in fibrosis or neutrophil recruitment, respectively. These niche factors might be associated with increased liver metastasis.

Matrix metalloproteinase functions in hepatic injury and fibrosis

Liver fibrosis is the most common final outcome for chronic liver diseases. The complex pathogenesis includes hepatic parenchymal damage as a result of a persistent noxe, activation and recruitment of immune cells, activation of hepatic stellate cells, and the synthesis of fibrotic extracellular matrix (ECM) components leading to scar formation. Clinical studies and animal models demonstrated that fibrosis can be reversible. In this regard matrix metalloproteinases (MMPs) have been focused as therapeutic targets due to their ability to modulate tissue turnover during fibrogenesis as well as regeneration and, of special interest, due to their influence on cellular behavior like proliferation, gene expression, and apoptosis that, in turn, impact fibrosis and regeneration. The current review aims to summarize and update the knowledge about expression pattern and the central roles of MMPs in hepatic fibrosis.

Evaluating the antifibrotic potency of galunisertib in a human ex vivo model of liver fibrosis

BACKGROUND AND PURPOSE

Liver fibrosis is a major cause of liver-related mortality and, so far, no effective antifibrotic drug is available. Galunisertib, a TGF-β receptor type I kinase inhibitor, is a potential candidate for the treatment of liver fibrosis. Here, we evaluated the potency of galunisertib in a human ex vivo model of liver fibrosis.

EXPERIMENTAL APPROACH

Antifibrotic potency and associated mechanisms were studied ex vivo, using both healthy and cirrhotic human precision-cut liver slices. Fibrosis-related parameters, both transcriptional and translational level, were assessed after treatment with galunisertib.

KEY RESULTS

Galunisertib showed a prominent antifibrotic potency. Phosphorylation of SMAD2 was inhibited, while that of SMAD1 remained unchanged. In healthy and cirrhotic human livers, spontaneous transcription of numerous genes encoding collagens, including collagen type I, α 1, collagen maturation, non-collageneous extracellular matrix (ECM) components, ECM remodelling and selected ECM receptors was significantly decreased. The reduction of fibrosis-related transcription was paralleled by a significant inhibition of procollagen I C-peptide released by both healthy and cirrhotic human liver slices. Moreover, galunisertib showed similar antifibrotic potency in human and rat lives.

CONCLUSIONS AND IMPLICATIONS

Galunisertib is a drug that deserves to be further investigated for the treatment of liver fibrosis. Inhibition of SMAD2 phosphorylation is probably a central mechanism of action. In addition, blocking the production and maturation of collagens and promoting their degradation are related to the antifibrotic action of galunisertib.

PNPLA3 overexpression results in reduction of proteins predisposing to fibrosis

Liver fibrosis is a pathological scarring response to chronic hepatocellular injury and hepatic stellate cells (HSCs) are key players in this process. PNPLA3 I148M is a common variant robustly associated with liver fibrosis but the mechanisms underlying this association are unknown. We aimed to examine a) the effect of fibrogenic and proliferative stimuli on PNPLA3 levels in HSCs and b) the role of wild type and mutant PNPLA3 overexpression on markers of HSC activation and fibrosis.

Here, we show that PNPLA3 is upregulated by the fibrogenic cytokine transforming growth factor-beta (TGF-β), but not by platelet-derived growth factor (PDGF), and is involved in the TGF-β-induced reduction in lipid droplets in primary human HSCs. Furthermore, we show that retinol release from human HSCs ex vivo is lower in cells with the loss-of-function PNPLA3 148M compared with 148I wild type protein. Stable overexpression of PNPLA3 148I wild type, but not 148M mutant, in human HSCs (LX-2 cells) induces a reduction in the secretion of matrix metallopeptidase 2 (MMP2), tissue inhibitor of metalloproteinase 1 and 2 (TIMP1 and TIMP2), which is mediated by retinoid metabolism. In conclusion, we show a role for PNPLA3 in HSC activation in response to fibrogenic stimuli. Moreover, we provide evidence to indicate that PNPLA3-mediated retinol release may protect against liver fibrosis by inducing a specific signature of proteins involved in extracellular matrix remodelling.

Lipopolysaccharides induce Smad2 phosphorylation through PI3K/Akt and MAPK cascades in HSC-T6 hepatic stellate cells

AIMS

Endotoxemia and its pro-fibrogenic signaling play a significant role in the development of hepatic fibrosis. This study investigated whether lipopolysaccharide (LPS) directly activate cultured HSC-T6 hepatic stellate cells (HSCs) through triggering Smad-dependent pro-fibrogenic signaling pathway.

MAIN METHODS

Direct cell counting and assays for cell proliferation and migration were used to measure the effects of LPS on HSC behaviors. Quantitative PCR, Western blot, and gelatin zymography were used to quantify the molecular effects of LPS on expression of HSC activation markers and signaling activity.

KEY FINDINGS

Long-term exposure to LPS exhibited moderately stimulatory effect on HSC cell growth. A wound-healing cell migration assay showed that LPS suppressed HSC-T6 cell migration. qPCR and Western blotting detection indicated that LPS treatment induced upregulation of type I and IV collagens, α-smooth muscle actin (α-SMA), and matrix metalloproteinase-9 (MMP-9). Gelatin zymography confirmed that LPS elevated MMP-9, but not MMP-2 gelatinolytic activity. Moreover, LPS immediately stimulated Akt, EKR1/2, JNK, p38 MAPK, and Smad2 hyperphosphorylation, supporting that LPS directly triggers pro-fibrogenic Smad signaling cascade without TGF-β1 stimulation. Kinase blockade experiments demonstrated the involvement of PI3K/Akt, JNK, p38 MAPK, but not ERK1/2 signaling activation in the LPS-elicited Smad2 phosphorylation as well as the overexpression of type I collagen and α-SMA in HSC-T6 cells.

SIGNIFICANCE

These findings demonstrate that LPS exerts pro-fibrogenic effect through activation and transformation of HSCs. The tissue-remodeling effect of LPS may be attributable to its ability to activate non-canonical Smad pathway through PI3K/Akt and MAPK signaling cascades.

The Contribution of Matrix Metalloproteinase-1 Genotypes to Hepatocellular Carcinoma Susceptibility in Taiwan

BACKGROUND/AIM

Metalloproteinases (MMPs) are a family of proteases which have been shown to be overexpressed in various types of cancers. However, the contribution of MMP1 genotype to hepatocellular carcinoma (HCC) has not been well studied. This study aimed to evaluate the contribution of MMP1 promoter 1607 genotype to the risk of HCC in Taiwan, where HCC incidence is relatively high in the world.

MATERIALS AND METHODS

In this case-control study, MMP1 genotype and its interaction with consumption of cigarettes and alcohol in determining HCC risk was investigated among 298 HCC patients and 889 age- and gender-matched healthy controls.

RESULTS

The percentages of ever smokers and ever alcohol drinkers were much higher in the case group than in the control group. The percentages of 2G/2G, 1G/2G and 1G/1G for MMP1 promoter 1607 genotype were 37.2%, 38.3% and 24.5% in the HCC group and 34.8%, 44.0% and 21.2% in the control group, respectively (p for trend=0.2048). The allelic frequency distribution analysis showed the variant 1G allele of MMP1 promoter 1607 conferred similar HCC susceptibility as the wild-type 2G allele (odds ratio (OR)=1.01, 95% confidence interval (CI)=0.84-1.22, p=0.8735). As for the gene-lifestyle interaction, there was an obvious protective effect of MMP1 promoter 1607 1G allele on the risk of HCC among non-smokers, but not non-smokers, even alcohol drinkers or non-drinkers.

CONCLUSION

The 1G allele of MMP1 promoter 1607 may have a protective effect on HCC risk for non-smokers in Taiwan and further validations are needed in other population groups.

Peginterferon Therapy in Children With Chronic Hepatitis C: A Nationwide, Multicenter Study in Japan, 2004-2013

OBJECTIVES

The aim of the present study was to review the medical treatment of Japanese children and adolescents with chronic hepatitis C in the past 10 years.

METHODS

This nationwide, multicenter study evaluated patients who were younger than 18 years of age when diagnosed with chronic hepatitis C virus (HCV) infection and were treated with pegylated interferon (PEG-IFN) monotherapy or PEG-IFN/ribavirin (RBV) combination therapy between 2004 and 2013. The subjects' median age was 10 (3-18) years, with a male to female ratio of 52:50 and a genotype-1 to genotype-2 ratio of 45:57. Among the 102 patients, 18 received PEG-IFN monotherapy and 84 received PEG-IFN/RBV combination therapy. The IL28B genotype polymorphism was analyzed in patients infected with genotype-1.

RESULTS

In patients with HCV genotype-1 infections, sustained virological response (SVR) rates obtained by PEG-IFN monotherapy and by PEG-IFN/RBV combination therapy were 100% (2/2) and 72% (31/43), respectively. In patients with HCV genotype-2 infections, SVRs were 75% (12/16) and 100% (41/41), respectively. In 32 genotype-1 patients available for the IL28B genotype (rs8099917), SVR was achieved in more patients in the IL28B major allele group than in the minor allele group (15/17 vs 7/15, P = 0.021) after PEG-IFN/RBV combination therapy. The frequencies of adverse events were similar between the treatment regimens.

CONCLUSIONS

Overall, both therapies showed encouraging results, and were reasonably safe in children and adolescents with chronic hepatitis C. The IL28B genotype was useful for predicting the treatment response to PEG-IFN/RBV combination therapy in this cohort.

Basement membrane fragments in the context of the epithelial-to-mesenchymal transition

The epithelial-to-mesenchymal transition (EMT) enables cells of epithelial phenotype to become motile and change to a migratory mesenchymal phenotype. EMT is known to be a fundamental requisite for tissue morphogenesis, and EMT-related pathways have been described in cancer metastasis and tissue fibrosis. Epithelial structures are marked by the presence of a sheet-like extracellular matrix, the basement membrane, which is assembled from two major proteins, laminin and collagen type IV. This specialized matrix is essential for tissue function and integrity, and provides an important barrier to the potential pathogenic migration of cells. The profound phenotypic transition in EMT involves the epithelial cells disrupting the basement membrane. Matrix metalloproteinases (MMPs) are known to cleave components of basement membranes, but MMP-basement membrane crosstalk during EMT in vivo is poorly understood. However, MMPs have been reported to play a role in EMT-related processes and a variety of basement membrane fragments have been shown to be released by specific MMPs in vitro and in vivo exhibiting distinct biological activities. This review discusses general considerations regarding the basement membrane in the context of EMT, a possible role for specific MMPs in EMT and highlights biologically active basement membrane fragments liberated by MMPs.

Pigment epithelium-derived factor and matrix metalloproteinase-9 in liver cirrhosis

BACKGROUND/AIM

The aim of this study was to assess the role of serum pigment epithelium-derived factor (PEDF) and matrix metalloproteinase-9 (MMP-9) in progression of liver cirrhosis and development of hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

Serum levels of PEDF and MMP-9 were tested in 212 patients with liver cirrhosis and in a control group of 30 healthy volunteers. HCC was diagnosed in 45 of the 212 patients studied (21%).

RESULTS

Serum PEDF and MMP-9 were higher in the study group than that in the control group (P < 0.001). In patients with alcoholic or mixed (alcoholic and viral hepatitis-related) cirrhosis, serum PEDF was higher than that in other patients (13970.2 ± 13406.9 ng/ml vs. 8563.5 ± 9602.7 ng/ml, P = 0.008). In patients with viral hepatitis-related cirrhosis, significantly higher PEDF levels were recorded in those with HCC (13429.1 ± 12045.8) than that in patients without HCC (6660.1 ± 7927.1; P = 0.04). There was a trend for higher serum MMP-9 in patients with HCC (5778.7 ± 12426.6 vs. 1389.8 ± 1944.7 in those without HCC; P = 0.07). Significant negative correlation between serum MMP-9 and serum alpha-fetoprotein in patients with HCC was observed (r = -0.54; P = 0.04).

CONCLUSION

Serum PEDF and MMP-9 could be auxiliary markers in diagnosis of HCC, especially in patients with low alpha-fetoprotein level. Alcohol consumption can affect serum PEDF.

Plasma levels of matrix metalloproteinase-2 and -9 in male and female patients with cirrhosis of different aetiologies

BACKGROUND

Liver fibrosis and cirrhosis may be reversible in some circumstances. Reliable diagnostic tests are necessary for monitoring hepatic fibrogenesis. Matrix metalloproteinase (MMP)-2 and MMP-9 are two of the major MMPs in the circulation and may be most relevant to hepatic fibrosis. The behaviour of MMPs may be significantly different in men and women and may also differ in cases of cirrhosis of various aetiologies.

AIMS

To evaluate the manifestations of MMP-2 and MMP-9 in liver cirrhosis of different aetiologies in men and women and to compare these patterns with those of healthy controls.

METHODS

We measured MMP-2 and MMP-9 levels in plasma samples from 112 patients with cirrhosis and 112 age- and gender-matched healthy controls. We then correlated these MMP levels with gender and disease aetiology.

RESULTS

Plasma MMP-2 concentrations in patients showed a trend towards increasing values with cirrhosis severity and were markedly increased in patients regardless of gender and aetiology compared with healthy controls (p<0.0001). Plasma mean MMP-9 levels were comparable in patients with cirrhosis and controls, but increased with disease severity. They were significantly lower in patients (130.5 ng/mL), female patients (85.4 ng/mL) and male patients (150.4 ng/mL) with mild cirrhosis than in controls (163.2 ng/mL), female controls (162.5 ng/mL) and male controls (163.3 ng/mL) (p=0.001, 0.041 and 0.009, respectively). MMP-2 and MMP-9 concentrations were not significantly different between genders among controls and among various patient subgroups.

CONCLUSIONS

Plasma MMP-2 level may be a useful diagnostic marker for monitoring hepatic fibrogenesis in patients with disease of different aetiologies.

The interplay between hepatic stellate cells and hepatocytes in an in vitro model of NASH

BACKGROUND & AIM

A complex interplay exists between hepatocytes and hepatic stellate cells (HSC) in hepatic fibrogenesis. The activation of HSCs after liver injury leads to production of extracellular matrix (ECM). Co-culture models could be useful to mimic the liver microenvironment. This study evaluates the effect of free fatty acids (FFA) on HSC cells and the interplay with hepatocytes via both soluble-mediator and cell-cell contact.

METHODS

The human hepatocyte cell line (HuH7) and HSC cells (LX2) were exposed to FFA for 24 h in 3 different experimental set-ups: (A) monoculture of HSC; (B) Transwell® system (effect of soluble mediators); and (C) Simultaneous Co-Culture (SCC) (cell-to-cell connections). Intracellular FFA accumulation was assessed qualitatively (microscopy) and quantitatively (flow cytometry); the activation of HSC (alpha smooth muscle actin, α-SMA) expression of ECM components were quantified by RT-PCR.

RESULTS

FFA exposure induces intracellular fat accumulation in all the experimental set-up but the expression of α-SMA was significantly increased only in SCC. On the contrary, the expression of ECM was substantially decreased in the transwell® system.

CONCLUSIONS

The HSC activation is independent of FFA accumulation but requires cell-to-cell interaction with hepatocyte. On the contrary, the gene regulation of ECM components seems to occur through paracrine mediators.

Therapeutic potential of amniotic-fluid-derived stem cells on liver fibrosis model in mice

OBJECTIVE

Liver fibrosis results from the wound healing response to chronic liver damage. Advanced liver fibrosis results in cirrhosis and liver failure, and liver transplantation is often the only option for effective therapy; however, the shortage of available donor livers limits this treatment. Thus, new therapies for advanced liver fibrosis are essential.

MATERIALS AND METHODS

Amniotic fluid contains an abundance of stem cells, which are derived from all three germ layers of the developing fetus. These cells do not induce teratomas in vivo and do not pose any ethical concerns. To generate liver fibrosis models, male ICR mice were treated with CCl4 via oral gavage for 4 weeks, and the serum levels of glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, and albumin were higher than in the control group following chemical induction. To assess the potential of amniotic-fluid-derived stem cells (mAFSCs) to ameliorate liver fibrosis in vivo, mAFSCs were isolated from amniotic fluid of 13.5-day-old transgenic mice, which globally express the fluorescent protein, enhanced green fluorescent protein (EGFP), for tracing purposes (EGFP-mAFSCs). Single cells were injected via the mesentery (1 × 10(6) cells/mouse) of transplanted mice with liver fibrosis.

RESULTS

Four weeks after EGFP-mAFSC transplantation, the serum glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, and albumin levels of recipient mice in the EGFP-mAFSC-injected group were significantly decreased when compared with mice in the saline-injected group. Additionally, fibrotic tissues were evaluated using Masson's trichrome staining 4 weeks after cell transplantation. Shrinkage of the fibrotic area was observed in the EGFP-mAFSC-injected group. The tissue-repair effects were also confirmed by hydroxyproline content analysis.

CONCLUSION

The possible repair mechanism from our data revealed that EGFP-mAFSCs may fuse with the recipient liver cells. Overall, EGFP-mAFSCs can ameliorate liver fibrosis in mice, thus providing insight into the future development of regenerative medicine.

Fibronectin localization and fibrillization are affected by the presence of serum in culture media

In vitro models of fibrotic phenomena are often based on the fibroblast-myofibroblast transition as the contraction-triggering cellular event. There are, however, multiple sources of concern regarding the appropriateness of such models; a first and widely investigated issue is the often inappropriate nature of the interactions between mesenchymal cells and surrounding/underlying matrix/substrate. A second set of problems concerns the composition of the fluid phase, which includes both dispersed/dissolved paracrine messengers and matrix elements. In this study, we have focused on the effects that serum may generate. We have observed that A) serum causes high variability in the expression of typical markers of myofibroblast differentiation (ED-A fibronectin and α-Smooth Muscle Actin) upon treatment with TGF-β1; this is probably due to intrinsic variability of cytokine concentrations in different batches of serum. B) the fibrillization of endogenous fibronectin is partially hampered and its localization changed from ventral (on the substrate) to dorsal (upper surface); the latter morphology appears to be largely overlooked in literature, even though it may have a significant role in terms of mechanotransductive signaling. This quite dramatic change possibly occurs as a result of competition with serum proteins, although our data seem to rule out a direct role of serum fibronectin.

Matrix metalloproteinases in liver injury, repair and fibrosis

The liver is a large highly vascularized organ with a central function in metabolic homeostasis, detoxification, and immunity. Due to its roles, the liver is frequently exposed to various insults which can cause cell death and hepatic dysfunction. Alternatively, the liver has a remarkable ability to self-repair and regenerate after injury. Liver injury and regeneration have both been linked to complex extracellular matrix (ECM) related pathways. While normal degradation of ECM components is an important feature of tissue repair and remodeling, irregular ECM turnover contributes to a variety of liver diseases. Matrix metalloproteinases (MMPs) are the main enzymes implicated in ECM degradation. MMPs not only remodel the ECM, but also regulate immune responses. In this review, we highlight some of the MMP-attributed roles in acute and chronic liver injury and emphasize the need for further experimentation to better understand their functions during hepatic physiological conditions and disease progression.

Anti-fibrotic effect of PF2401-SF, a standardized fraction of Salvia miltiorrhiza, in thioacetamide-induced experimental rats liver fibrosis

We previously reported the in vitro and in vivo hepatoprotective and anti-fibrotic effects of PF2401-SF, a standardized fraction of Salvia miltiorrhiza, against acute and subacute liver injury. The aim of this study was to investigate the effect of PF2401-SF on liver fibrosis induced by thioacetamide (TAA), a chronic liver injury model (12 weeks) that closely resembles fibrosis and cirrhosis in humans. Hepatoprotective activity was indicated by low serum levels of the markers aspartate amino transferase and alanine amino transferase .In addition, compared to the TAA-group livers, the PF2401-SF-treated liver tissues showed no fibrous tissue deposition in the portal areas, hepatocyte morphology more closely resembling normal tissue morphology, and significantly reduced collagen deposition. Furthermore, downregulation of collagen 1(α) and tissue inhibitor of metalloproteinase (TIMP)1 protein and mRNA expression also supports PF2401-SF's anti-fibrotic effect. We also observed reduced expression of α-smooth muscle actin (α-SMA), an important marker of hepatic stellate cells (HSCs) activation. From these results, we conclude that PF2401-SF's anti-fibrotic mechanism in the TAA model involves reduced HSC activation, and may be mediated by downregulation of central markers of fibrosis, including collagen 1(α), TIMP1, and α-SMA.

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.

Hepatic inflammation and progressive liver fibrosis in chronic liver disease

Chronic liver inflammation drives hepatic fibrosis, and current immunosuppressive, anti-inflammatory, and anti-viral therapies can weaken this driver. Hepatic fibrosis is reversed, stabilized, or prevented in 57%-79% of patients by conventional treatment regimens, mainly by their anti-inflammatory actions. Responses, however, are commonly incomplete and inconsistently achieved. The fibrotic mechanisms associated with liver inflammation have been clarified, and anti-fibrotic agents promise to improve outcomes as adjunctive therapies. Hepatitis C virus and immune-mediated responses can activate hepatic stellate cells by increasing oxidative stress within hepatocytes. Angiotensin can be synthesized by activated hepatic stellate cells and promote the production of reactive oxygen species. Anti-oxidants (N-acetylcysteine, S-adenosyl-L-methionine, and vitamin E) and angiotensin inhibitors (losartin) have had anti-fibrotic actions in preliminary human studies, and they may emerge as supplemental therapies. Anti-fibrotic agents presage a new era of supplemental treatment for chronic liver disease.

Clinical and prognostic role of circulating MMP-2 and its inhibitor TIMP-2 in HCC patients prior to and after trans-hepatic arterial chemo-embolization

BACKGROUND AND AIMS

Trans-hepatic arterial chemo-embolization is the most commonly used treatment for unresectable hepatocellular carcinoma. The prognostic impact of tumor biomarkers has not therefore been evaluated in this treatment. Imbalance between matrix metalloproteinase-2 and tissue inhibitor metalloproteinase-2 is considered to play an important role in extracellular matrix remodeling and degradation. Higher serum levels of MMP-2 have been shown to predict a poor prognosis and shorter overall survival in HCC after TACE. The objective of this study was to evaluate the serum levels of MMP-2 and TIMP-2 in HCC patients before and after TACE to evaluate their clinical significance and usefulness as prognostic biomarkers.

METHODS

MMP-2 and TIMP-2 levels were measured by ELISA in 75 HCC patients and 30 healthy controls. Sera MMP-2 and TIMP-2 were correlated with clinico-pathological features.

RESULTS

The mean serum MMP-2 and TIMP-2 levels of HCC patients before TACE were 1700±71ng/mL and 89±45ng/mL respectively, significantly higher than that of the control group: 771±60ng/mL (p<0.0001, t-test) and 25.7±20ng/mL respectively (p<0.0001, t-test). A significant decrease of MMP-2 levels after 1 and 3months compared to baseline time was observed (p<0.0001), while with TIMP-2 a gradual increase in serum before and after TACE (p<0.01) was detected. No significant correlation between serum MMP-2 levels and other clinico-pathological features was observed. Patients with serum MMP-2 >1500ng/mL (median value) had worse overall and recurrence-free survival compared with those with serum MMP-2 levels <1500ng/mL before treatment.

CONCLUSION

Higher serum MMP-2 levels and MMP-2/TIMP-2 ratio could predict poor prognosis after TACE, suggesting prognostic role of these biomarkers in HCC.

Hepatocyte polarity

Hepatocytes, like other epithelia, are situated at the interface between the organism's exterior and the underlying internal milieu and organize the vectorial exchange of macromolecules between these two spaces. To mediate this function, epithelial cells, including hepatocytes, are polarized with distinct luminal domains that are separated by tight junctions from lateral domains engaged in cell-cell adhesion and from basal domains that interact with the underlying extracellular matrix. Despite these universal principles, hepatocytes distinguish themselves from other nonstriated epithelia by their multipolar organization. Each hepatocyte participates in multiple, narrow lumina, the bile canaliculi, and has multiple basal surfaces that face the endothelial lining. Hepatocytes also differ in the mechanism of luminal protein trafficking from other epithelia studied. They lack polarized protein secretion to the luminal domain and target single-spanning and glycosylphosphatidylinositol-anchored bile canalicular membrane proteins via transcytosis from the basolateral domain. We compare this unique hepatic polarity phenotype with that of the more common columnar epithelial organization and review our current knowledge of the signaling mechanisms and the organization of polarized protein trafficking that govern the establishment and maintenance of hepatic polarity. The serine/threonine kinase LKB1, which is activated by the bile acid taurocholate and, in turn, activates adenosine monophosphate kinase-related kinases including AMPK1/2 and Par1 paralogues has emerged as a key determinant of hepatic polarity. We propose that the absence of a hepatocyte basal lamina and differences in cell-cell adhesion signaling that determine the positioning of tight junctions are two crucial determinants for the distinct hepatic and columnar polarity phenotypes.

Antifibrotic properties of transarterial oncolytic VSV therapy for hepatocellular carcinoma in rats with thioacetamide-induced liver fibrosis

Recombinant vesicular stomatitis virus (VSV) shows promise for the treatment of hepatocellular carcinoma (HCC), but its safety and efficacy when administered in a setting of hepatic fibrosis, which occurs in the majority of clinical cases, is unknown. We hypothesized that VSV could provide a novel benefit to the underlying fibrosis, due to its ability to replicate and cause cell death specifically in activated hepatic stellate cells. In addition to the ability of VSV to produce a significant oncolytic response in HCC-bearing rats in the background of thioacetamide-induced hepatic fibrosis without signs of hepatotoxicity, we observed a significant downgrading of fibrosis stage, a decrease in collagen content in the liver, and modulation of gene expression in favor of fibrotic regression. Together, this work suggests that VSV is not only safe and effective for the treatment of HCC with underlying fibrosis, but it could potentially be developed for clinical application as a novel antifibrotic agent.

Fasting reduces liver fibrosis in a mouse model for chronic cholangiopathies

Chronic cholangiopathies often lead to fibrosis, as a result of a perpetuated wound healing response, characterized by increased inflammation and excessive deposition of proteins of the extracellular matrix. Our previous studies have shown that food deprivation suppresses the immune response, which led us to postulate its beneficial effects on pathology in liver fibrosis driven by portal inflammation. We investigated the consequences of fasting on liver fibrosis in Abcb4(-/-) mice that spontaneously develop it due to a lack of phospholipids in bile. The effect of up to 48h of food deprivation was studied by gene expression profiling, (immuno)histochemistry, and biochemical assessments of biliary output, and hepatic and plasma lipid composition. In contrast to increased biliary output in the wild type counterparts, bile composition in Abcb4(-/-) mice remained unchanged with fasting and did not influence the attenuation of fibrosis. Markers of inflammation, however, dramatically decreased in livers of Abcb4(-/-) mice already after 12h of fasting. Reduced presence of activated hepatic stellate cells and actively increased tissue remodeling further propelled a decrease in parenchymal fibrosis in fasting. This study is the first to show that food deprivation positively influences liver pathology in a fibrotic mouse model for chronic cholangiopathies, opening a door for new strategies to improve liver regeneration in chronic disease.

Markers in nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD), the most common liver disorder worldwide, encompasses a spectrum of abnormal liver histology ranging from simple steatosis to nonalcoholic steatohepatitis (NASH) and cirrhosis. Population studies show that NAFLD is strongly associated with insulin resistance, obesity, type 2 diabetes mellitus, and lipid abnormalities. In the context of hepatic steatosis, factors that promote cell injury, inflammation, and fibrosis include oxidative stress, early mitochondrial dysfunction, endoplasmic reticulum stress, iron accumulation, apoptosis, adipocytokines, and stellate cell activation. The exact NASH prevalence is unknown because of the absence of simple noninvasive diagnostic tests. Although liver biopsy is the "gold standard" for the diagnosis of NASH, other tests are needed to facilitate the diagnosis and greatly reduce the requirement for invasive liver biopsy. In addition, the development of new fibrosis markers in NASH is needed to facilitate the assessment of its progression and the effectiveness of new therapies. The aim of this chapter, which is overview of biomarkers in NASH, is to establish a systematic approach to laboratory findings of the disease.

Matrix metalloproteinase-9 contributes to the mobilization of bone marrow cells in the injured liver

Effective mobilization of hematopoietic stem cells (HSCs) in injured organs has not been established. Matrix metalloproteinase-9 (MMP-9) is known to release HSCs from bone marrow (BM) into the peripheral blood, but its role in the recruitment of HSCs to injured organs is unclear. In this study we tried to clarify the role of the host MMP-9 in trafficking of HSCs toward the injured liver, especially the relation of MMP-9 with the chemokine receptor 4 (CXCR4)-chemokine ligand 12 (CXCL12) axis, and to examine whether MMP-9 deficiency affects BM cell trafficking to the injured liver in mice. In vitro, we investigated the effect of MMP-9 on migration activity and CXCR4 expression on lineage-negative (Lin(-)) BM cells. In vivo, we induced acute and chronic liver injury in MMP-9 knockout (KO) and control mice by inoculation of carbon tetrachloride, followed by transplantation of Lin(-) BM cells obtained from enhanced green fluorescent protein (EGFP)-transgenic mice, and counted the BM cells mobilized in the injured liver. In a migration assay, active MMP-9, but not proMMP-9, increased the number of migrated Lin(-) BM cells, which was inhibited by tissue inhibitor of metalloproteinase-1 or a MMP inhibitor. This chemoattractant function by MMP-9 was synergistic when cotreated with CXCL12. CXCR4 expression on Lin(-) BM cells was dose- and time-dependently increased by active MMP-9. At the same time, treatment with MMP-9 enhanced CXCL12 expression, and CXCL12 reciprocally increased MMP-9 expression in BM cells. In in vivo studies, many EGFP(+) cells were seen in control recipient mice. In contrast, few EGFP(+) cells were observed in MMP-9 KO mice. BM cells tended to differentiate into desmin(+) cells. In conclusion, MMP-9 contributes to the mobilization of BM cells in the injured liver by upregulating the expression of CXCR4 on Lin(-) BM cells and attracting BM cells along its gradient of CXCL12. Therefore, host MMP-9 plays an important role in BM cell migration in the injured liver.

Anti-inflammatory/anti-fibrotic effects of the hepatoprotective silymarin and the schistosomicide praziquantel against Schistosoma mansoni-induced liver fibrosis

BACKGROUND

Praziquantel (PZQ) is an isoquinoline derivative (2-cyclohexylcarbonyl-1, 2, 3, 6, 7, 11b-hexahydro-4H-pyrazino{2,1-a}-isoquinoline-4-one), and is currently the drug of choice for all forms of schistosomiasis. Silymarin, a standardized milk thistle extract, of which silibinin is the main component, is known for its hepatoprotective, anti-inflammatory, antioxidant activities, and hepatocyte regeneration. This study investigates the anti-inflammatory/anti-fibrotic effects of silymarin and/or PZQ on schistosomal hepatic fibrosis.

METHODS

Schistosoma mansoni-infected mice were divided into two large groups (I & II), each with four subgroups and were run in parallel. (i) Infected untreated; (ii) treated with silymarin, starting from the 4th (3 weeks before PZQ therapy) or 12th (5 weeks after PZQ therapy) weeks post infection (PI); (iii) treated with PZQ in the 7th week PI; and (iv) treated with silymarin, as group (ii) plus PZQ as group (iii). Comparable groups of uninfected mice run in parallel with the infected groups. Mice of groups I and II were killed 10 and 18 weeks PI, respectively. Hepatic content of hydroxyproline (HYP), serum levels and tissue expression of matrix metalloproteinase-2 (MMP-2), transforming growth factor-β1 (TGF-β1) and number of mast cells were determined. In addition, parasitological, biochemical and histological parameters that reflect disease severity and morbidity were examined.

RESULTS

Silymarin caused a partial decrease in worm burden; hepatic tissue egg load, with an increase in percentage of dead eggs; modulation of granuloma size, with significant reduction of hepatic HYP content; tissue expression of MMP-2, TGF-β1; number of mast cells, with conservation of hepatic reduced glutathione (GSH). PZQ produced complete eradication of worms, eggs and alleviated liver inflammation and fibrosis. The best results were obtained, in most parameters studied, in groups of mice treated with silymarin in addition to PZQ.

CONCLUSIONS

Our results point to silymarin as a promising anti-inflammatory and anti-fibrotic agent; it could be introduced as a therapeutic tool with PZQ in the treatment of schistosomal liver fibrosis, but further studies on mechanisms of silymarin and PZQ in chronic liver diseases may shed light on developing therapeutic methods in clinical practice.

Current status of novel antifibrotic therapies in patients with chronic liver disease

Fibrosis accumulation is a dynamic process resulting from a wound-healing response to acute or chronic liver injury of all causes. The cascade starts with hepatocyte necrosis and apoptosis, which instigate inflammatory signaling by chemokines and cytokines, recruitment of immune cell populations, and activation of fibrogenic cells, culminating in the deposition of extracellular matrix. These key elements, along with pathways of transcriptional and epigenetic regulation, represent fertile therapeutic targets. New therapies include drugs specifically designed as antifibrotics, as well as drugs already available with well-established safety profiles, whose mechanism of action may also be antifibrotic. At the same time, the development of noninvasive fibrogenic markers, and techniques (e.g. fibroscan), as well as combined scoring systems incorporating serum and clinical features will allow improved assessment of therapy response. In aggregate, the advances in the elucidation of the biology of fibrosis, combined with improved technologies for assessment will provide a comprehensive framework for design of antifibrotics and their analysis in well-designed clinical trials. These efforts may ultimately yield success in halting the progression of, or reversing, liver fibrosis.

Non-invasive markers for hepatic fibrosis

With great advancements in the therapeutic modalities used for the treatment of chronic liver diseases, the accurate assessment of liver fibrosis is a vital need for successful individualized management of disease activity in patients. The lack of accurate, reproducible and easily applied methods for fibrosis assessment has been the major limitation in both the clinical management and for research in liver diseases. However, the problem of the development of biomarkers capable of non-invasive staging of fibrosis in the liver is difficult due to the fact that the process of fibrogenesis is a component of the normal healing response to injury, invasion by pathogens, and many other etiologic factors. Current non-invasive methods range from serum biomarker assays to advanced imaging techniques such as transient elastography and magnetic resonance imaging (MRI). Among non-invasive methods that gain strongest clinical foothold are FibroScan elastometry and serum-based APRI and FibroTest. There are many other tests that are not yet widely validated, but are none the less, promising. The rate of adoption of non-invasive diagnostic tests for liver fibrosis differs from country to country, but remains limited. At the present time, use of non-invasive procedures could be recommended as pre-screening that may allow physicians to narrow down the patients' population before definitive testing of liver fibrosis by biopsy of the liver. This review provides a systematic overview of these techniques, as well as both direct and indirect biomarkers based approaches used to stage fibrosis and covers recent developments in this rapidly advancing area.

Graft fibrosis in patients with biliary atresia after pediatric living-related liver transplantation

Although an LDLT can successfully treat biliary atresia (BA), some patients develop liver fibrosis or inflammation. To study the incidence and risk factors associated with these complications, we performed serial protocol biopsies. Twenty-four patients with BA who received a pediatric LDLT underwent protocol biopsies. All patients received standard tacrolimus-based immunosuppression and steroids. The last available biopsies were assessed. The mean age at the time of transplant was 4.8yr and the follow-up period ranged from 1.2 to 12.3yr. The GRWR ranged from 0.8% to 4.5%. The mean time from transplantation to the latest biopsy was 4.7yr. No complications occurred with the biopsy protocol. The last available biopsies for 13 (54%) and 4 (17%) patients indicated grade 1 and grade 2 portal fibrosis, respectively, and 14 patients (54%) had inflammation. No ductopenia was detected. A younger age at LDLT was significantly correlated with graft fibrosis (p=0.036). These results indicate that biopsy-proven fibrosis can be detected in patients with BA after LDLT, even in the context of normal liver function blood tests. Therefore, a serial biopsy is a safe and effective follow-up procedure for pediatric LDLT.

The use of pentoxifylline as adjuvant therapy with praziquantel downregulates profibrogenic cytokines, collagen deposition and oxidative stress in experimental schistosomiasis mansoni

This study investigates the possible use of pentoxifylline (PTX), with antifibrotic and anti-inflammatory properties, as adjuvant in treatment of schistosomal liver fibrosis through determination of some profibrogenic cytokines, oxidative stress and collagen deposition. Animals were classified into seven groups: normal control (i), Schistosoma mansoni-infected untreated (ii), infected treated with praziquantel (PZQ) curative, 1000mg/kg (iii) or sub curative, 200mg/kg dose (iv), infected treated with PTX alone (10mg/kg/day; 5days/wk) for 8weeks starting from the 2nd to the 10th week post infection (v), or in addition to curative (vi) or sub curative dose of PZQ (vii). Serum transforming growth factor-β1 (TGF-β1), tumor necrosis factor-α (TNF-α), matrix metalloproteinases-2 (MMP-2) and hepatic hydroxyproline (Hyp) content, glutathione related antioxidant enzymes and malondialdehyde (MDA) were determined. Results showed that S. mansoni infection produced remarkable elevations in the serum levels of TGF-β1, TNF-α, MMP-2 and the hepatic contents of Hyp, glutathione reductase (GR), MDA with significant reduction in reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and superoxide dismutase (SOD) when compared with their corresponding normal controls. Treatment of infected mice with PTX in addition to PZQ curative rather than its sub curative dose produced the best results evidenced by complete normalization in the previously mentioned serum and hepatic parameters.

CONCLUSION

PTX could attenuate liver fibrosis in early stages of S. mansoni infection through downregulation of profibrogenic cytokines, oxidative stress and collagen deposition.

Downregulation of matrix metalloproteinase-9 by melatonin during prevention of alcohol-induced liver injury in mice

Matrix metalloproteinases (MMPs) have been implicated in inflammatory and degradative processes in several diseases. The study aims to explore the mechanism of MMP-9 regulation in alcohol-induced acute liver injury and its protection by melatonin in mice. Alcohol-induced acute liver injury was induced in female Balb/C mice by ethanol administration and protection studies were carried out with a well-known antioxidant molecule, melatonin. Degree of liver injury was monitored by histological and biochemical analysis of liver tissues. Oral administration of ethanol in mouse caused significant increase in alanine amino transferase (ALT) activity in serum. Depletion of glutathione and enhancement of lipid peroxidation as well as protein oxidation was observed in liver tissues following ethanol treatment. However, melatonin exhibited potent hepatoprotective activity by inhibiting ALT activity and oxidative stress. Additionally, MMP-9 expression was increased by ethanol in a dose and time dependent manner in liver tissue and serum. Increased secretion of proMMP-9 was strongly correlated with the expression of proinflammatory cytokines e.g., tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL6. Melatonin showed hepatoprotective role by downregulation of MMP-9 and upregulation of tissue inhibitor of metalloproteases (TIMP-1) expression in liver tissue. Nuclear factor (NF)-κB, plays an important role in inducing inflammatory genes during oxidative stress, thus the role of NF-κB in ethanol-induced liver injury was investigated. Ethanol induced nuclear translocation of NF-κB and increased degradation of inhibitor of NF-κB (IκBα) in liver tissues. Moreover, ethanol-induced NF-κB translocation into nucleus was inhibited significantly by melatonin. This is the first study to elucidate the induction of MMP-9 expression by NF-κB-dependent pathway in ethanol-induced acute liver injury in mice. This study also identifies the novel role of melatonin in hepatoprotection via MMP-9 down regulation.

Advances in the regulation of liver regeneration

Liver regeneration is known to be a process involving highly organized and ordered tissue growth triggered by the loss of liver tissue, and remains a fascinating topic. A large number of genes are involved in this process, and there exists a sequence of stages that results in liver regeneration, while at the same time inhibitors control the size of the regenerated liver. The initiation step is characterized by priming of quiescent hepatocytes by factors such as TNF-α, IL-6 and nitric oxide. The proliferation step is the step during which hepatocytes enter into the cell cycle's G1 phase and are stimulated by complete mitogens including HGF, TGF-α and EGF. Hepatic stimulator substance, glucagon, insulin, TNF-α, IL-1 and IL-6 have also been implicated in regulating the regeneration process. Inhibitors and stop signals of hepatic regeneration are not well known and only limited information is available. Furthermore, the effects of other factors such as VEGF, PDGF, hypothyroidism, proliferating cell nuclear antigen, heat shock proteins, ischemic-reperfusion injury, steatosis and granulocyte colony-stimulating factor on liver regeneration are also systematically reviewed in this article. A tissue engineering approach using isolated hepatocytes for in vitro tissue generation and heterotopic transplantation of liver cells has been established. The use of stem cells might also be very attractive to overcome the limitation of donor liver tissue. Liver-specific differentiation of embryonic, fetal or adult stem cells is currently under investigation.