Reversal of hepatic fibrosis: pathophysiological basis of antifibrotic therapies

Recent Advancements in Antifibrotic Therapies for Regression of Liver Fibrosis

Cirrhosis is a severe form of liver fibrosis that results in the irreversible replacement of liver tissue with scar tissue in the liver. Environmental toxicity, infections, metabolic causes, or other genetic factors including autoimmune hepatitis can lead to chronic liver injury and can result in inflammation and fibrosis. This activates myofibroblasts to secrete ECM proteins, resulting in the formation of fibrous scars on the liver. Fibrosis regression is possible through the removal of pathophysiological causes as well as the elimination of activated myofibroblasts, resulting in the reabsorption of the scar tissue. To date, a wide range of antifibrotic therapies has been tried and tested, with varying degrees of success. These therapies include the use of growth factors, cytokines, miRNAs, monoclonal antibodies, stem-cell-based approaches, and other approaches that target the ECM. The positive results of preclinical and clinical studies raise the prospect of a viable alternative to liver transplantation in the near future. The present review provides a synopsis of recent antifibrotic treatment modalities for the treatment of liver cirrhosis, as well as a brief summary of clinical trials that have been conducted to date.

Heterogeneous Iron Oxide/Dysprosium Oxide Nanoparticles Target Liver for Precise Magnetic Resonance Imaging of Liver Fibrosis

Challenges remain in precisely diagnosing the progress of liver fibrosis in a noninvasive way. We here synthesized small (4 nm) heterogeneous iron oxide/dysprosium oxide nanoparticles (IO-DyO NPs) as a contrast agent (CA) for magnetic resonance imaging (MRI) to precisely diagnose liver fibrosis in vivo at both 7.0 and 9.4 T field strength. Our IO-DyO NPs can target the liver and show an increased T₂ relaxivity along with an increase of magnetic field strength. At a ultrahigh magnetic field, IO-DyO NPs can significantly improve spatial/temporal image resolution and signal-to-noise ratio of the liver and precisely distinguish the early and moderate liver fibrosis stages. Our IO-DyO NP-based MRI diagnosis can exactly match biopsy (a gold standard for liver fibrosis diagnosis in the clinic) but avoid the invasiveness of biopsy. Moreover, our IO-DyO NPs show satisfactory biosafety in vitro and in vivo. This work illustrates an advanced T₂ CA used in ultrahigh-field MRI (UHFMRI) for the precise diagnosis of liver fibrosis via a noninvasive means.

Therapeutic Effects of an Inhibitor of Thioredoxin Reductase on Liver Fibrosis by Inhibiting the Transforming Growth Factor-β1/Smads Pathway

Liver fibrosis is an important stage in the progression of liver injury into cirrhosis or even liver cancer. Hepatic stellate cells (HSCs) are induced by transforming growth factor-β1 (TGF-β1) to produce α-smooth muscle actin (α-SMA) and collagens in liver fibrosis. Butaselen (BS), which was previously synthesized by our group, is an organic selenium compound that exerts antioxidant and tumor cell apoptosis–promoting effects by inhibiting the thioredoxin (Trx)/thioredoxin reductase (TrxR) system. The aim of this study was to investigate the potential effects of BS on liver fibrosis and explore the underlying molecular mechanisms of its action. Liver fibrosis models were established using male BALB/c mice through intraperitoneal injection of CCl₄. BS was administered orally once daily at a dose of 36, 90, or 180 mg/kg. Silymarin (Si), which is a drug used for patients with nonalcoholic fatty liver disease and nonalcoholic steatohepatitis, was administered at a dose of 30 mg/kg per day as a control. The action mechanisms of BS against liver fibrosis progression were examined in HSCs. The study revealed that the activity and expression levels of TrxR were elevated in the mouse liver and serum after CCl₄-induced liver fibrosis. Oral administration of BS relieved the pathological state of mice with liver fibrosis, showing significant therapeutic effects against liver fibrosis. Moreover, BS not only induced HSC apoptosis but also inhibited the production of α-SMA and collagens by HSCs by downregulating the TGF-β1 expression and blocking the TGF-β1/Smads pathway. The results of the study indicated that BS inhibited liver fibrosis by regulating the TGF-β1/Smads pathway.

Effects of Carvedilol on the Expression of TLR4 and its Downstream Signaling Pathway in the Liver Tissues of Rats with Cholestatic Liver Fibrosis

Objectives:

This study was designed to investigate the effects of carvedilol on the expression of TLR4 and its downstream signaling pathway in the liver tissues of rats with cholestatic liver fibrosis and provide experimental evidence for clinical treatment of liver fibrosis with carvedilol.

Methods:

A total of fifty male Sprague Dawley rats were randomly divided into five groups (10 rats per group): sham operation (SHAM) control group, bile duct ligation (BDL) model group, low-dose carvedilol treatment group (0.1mg·kg-1·d-1), medium-dose carvedilol treatment group (1mg·kg-1·d-1), and high-dose carvedilol treatment group (10mg·kg-1·d-1). Rat hepatic fibrosis model was established by applying BDL. Forty-eight hours after the operation, carvedilol was administered twice a day. The blood and liver were simultaneously collected under the aseptic condition for further detection in two weeks after the operation. The alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBil) and albumin (Alb) in serum were measured. HE and Masson staining were used to determine hepatic fibrosis degree. Hydroxyproline assay was employed to detect liver collagen synthesis. Western Blot was used to measure the expression of TLR4, NF-κB p65 and β-arrestin2 protein. Quantitative analysis of TLR4, MyD88, TNF-α and IL-6 mRNA was performed by Realtime-PCR.

Results:

Compared with the SHAM group, the BDL group showed obvious liver injury, increased levels of inflammatory factors, and continued progression of liver fibrosis. The above changes in the BDL group were alleviated in the carvedilol treatment groups. The improvement effects augmented as dosages increased. In addition, compared with the BDL group, the reduction of the expressions of TLR4, MyD88 and NF-κB p65 in liver tissues and the increase of the expression of β -arrestin2 in the high-dose carvedilol group were more significant.

Conclusions:

Carvedilol can reduce the release of inflammatory mediators by downregulating TLR4 expression and inhibiting its downstream signaling pathway, thus playing a potential therapeutic role in cholestatic liver fibrosis.

WITHDRAWN: Effects of carvedilol on expression of TLR4 and its downstream signaling pathway in liver tissue of rats with cholestatic liver fibrosisjaundice

Ahead of Print article withdrawn by publisher.

OBJECTIVES

This study was designed to investigate the effects of carvedilol on the expression of TLR4 and its downstream signaling pathway in liver tissue of rats with cholestatic liver fibrosis, and provided experimental evidence for clinical treatment of liver fibrosis with carvedilol.?

METHODS

A total of fifty male Sprague Dawley rats were randomly divided into five groups (10 rats per group): sham surgery control group, bile duct ligation (BDL) model group, low-dose carvedilol treatment group (0.1mgkg-1d-1), medium-dose carvedilol treatment group (1mgkg-1d-1), high-dose carvedilol treatment group (10mgkg-1d-1). Rat hepatic fibrosis model was established by applying BDL. Forty-eight hours after the operation, carvedilol was administered twice a day. The blood and liver were simultaneously collected under the aseptic condition for further detection in two weeks after operation.?

RESULTS

Compared with the sham group, the BDL group showed obvious liver injury, increased levels of inflammatory factors, and continued progression of liver fibrosis. Carvedilol could alleviate the above changes. The improvement effects were augmenting as dosages increasing. In addition, compared with the BDL group, carvedilol can reduce the expressions of TLR4, MyD88 and NF-?B p65 in liver tissue and increase the expression of ?-arrestin2, and the effect in the high dose group was more obvious.

CONCLUSIONS

Carvedilol can reduce the release of inflammatory mediators by down-regulating TLR4 expression and inhibiting its downstream signaling pathway, thus playing a therapeutic role in cholestatic liver fibrosis.

Hepatic Stellate Cells and Hepatocarcinogenesis

Hepatic stellate cells (HSCs) are a significant component of the hepatocellular carcinoma (HCC) tumor microenvironment (TME). Activated HSCs transform into myofibroblast-like cells to promote fibrosis in response to liver injury or chronic inflammation, leading to cirrhosis and HCC. The hepatic TME is comprised of cellular components, including activated HSCs, tumor-associated macrophages, endothelial cells, immune cells, and non-cellular components, such as growth factors, proteolytic enzymes and their inhibitors, and other extracellular matrix (ECM) proteins. Interactions between HCC cells and their microenvironment have become topics under active investigation. These interactions within the hepatic TME have the potential to drive carcinogenesis and create challenges in generating effective therapies. Current studies reveal potential mechanisms through which activated HSCs drive hepatocarcinogenesis utilizing matricellular proteins and paracrine crosstalk within the TME. Since activated HSCs are primary secretors of ECM proteins during liver injury and inflammation, they help promote fibrogenesis, infiltrate the HCC stroma, and contribute to HCC development. In this review, we examine several recent studies revealing the roles of HSCs and their clinical implications in the development of fibrosis and cirrhosis within the hepatic TME.

Tanshinone IIA alters the transforming growth factor-1/Smads pathway in angiotensin II-treated rat hepatic stellate cells

Objective

To investigate the effects of tanshinone IIA on the transforming growth factor-β1 (TGF-β1)/Smads signaling pathway in angiotensin II-treated hepatic stellate cells (HSCs).

Methods

HSCs were cultured and treated with angiotensin II (10 μM) or angiotensin II (10 μM) plus tanshinone IIA (3, 10, or 30 μM). Cells were incubated for 48 hours and proliferation was determined with the Cell Counting Kit-8. The relative mRNA expression of TGF-β1, Smad4, and Smad7 was measured by quantitative real-time PCR, and the relative protein expression levels were investigated by western blotting.

Results

After angiotensin II treatment, cell proliferation was significantly accelerated. Furthermore, both the mRNA and protein expression of TGF-β1 and Smad4 was significantly up-regulated, while the mRNA and protein expression of Smad7 was significantly down-regulated compared with the control cells. Tanshinone IIA inhibited the observed effects of angiotensin II in a concentration-dependent manner, with significant inhibition exerted by tanshinone IIA at 10 and 30 μM.

Conclusions

Angiotensin II promotes the proliferation of HSCs, possibly by regulating the expression of components along the TGF-β1/Smads signaling pathway. Tanshinone IIA inhibits the angiotensin II-induced activation of this pathway, and may, therefore, have preventive and therapeutic effects in liver fibrosis.

Design of a Gene Panel to Expose the Versatile Role of Hepatic Stellate Cells in Human Liver Fibrosis

The pivotal cell involved in the pathogenesis of liver fibrosis, i.e., the activated hepatic stellate cell (HSC), has a wide range of activities during the initiation, progression and even regression of the disease. These HSC-related activities encompass cellular activation, matrix synthesis and degradation, proliferation, contraction, chemotaxis and inflammatory signaling. When determining the in vitro and in vivo effectivity of novel antifibrotic therapies, the readout is currently mainly based on gene and protein levels of α-smooth muscle actin (α-SMA) and the fibrillar collagens (type I and III). We advocate for a more comprehensive approach in addition to these markers when screening potential antifibrotic drugs that interfere with HSCs. Therefore, we aimed to develop a gene panel for human in vitro and ex vivo drug screening models, addressing each of the HSC-activities with at least one gene, comprising, in total, 16 genes. We determined the gene expression in various human stellate cells, ranging from primary cells to cell lines with an HSC-origin, and human liver slices and stimulated them with two key profibrotic factors, i.e., transforming growth factor β (TGFβ) or platelet-derived growth factor BB (PDGF-BB). We demonstrated that freshly isolated HSCs showed the strongest and highest variety of responses to these profibrotic stimuli, in particular following PDGF-BB stimulation, while cell lines were limited in their responses. Moreover, we verified these gene expression profiles in human precision-cut liver slices and showed similarities with the TGFβ- and PDGF-BB-related fibrotic responses, as observed in the primary HSCs. With this study, we encourage researchers to get off the beaten track when testing antifibrotic compounds by including more HSC-related markers in their future work. This way, potential compounds will be screened more extensively, which might increase the likelihood of developing effective antifibrotic drugs.

Downregulation of miR-152 contributes to the progression of liver fibrosis via targeting Gli3 in vivo and in vitro

The Gli family is known to be required for the activation of hedgehog signalling, which participates in the pathogenesis of liver fibrosis. The aim of the present study was to identify the association between microRNA (miR)-152 and GLI family zinc finger 3 (Gli3) and their roles in liver fibrosis. In a carbon tetrachloride (CCl₄)-treated rat model, fibrogenesis-associated indexes, including hydroxyproline content, collagen deposition, and α-smooth muscle actin (α-SMA) and albumin expression, were examined in in vivo and in vitro models. The expression of miR-152 and Gli3 in cells and tissues was determined by reverse transcription quantitative polymerase chain reaction and western blot analysis. The interaction of Gli3 and miR-152 was evaluated by bioinformatical analysis and a dual-luciferase reporter assay. The results demonstrated that miR-152 was significantly downregulated in serum samples from clinical patients, liver tissues from CCl₄-treated rats and activated LX2 cells. Furthermore, at the cellular level, the mRNA and protein expression levels of α-SMA and albumin were increased and decreased, respectively, in LX2 cells. Nevertheless, following transfection with an miR-152 mimic, the expression levels of α-SMA and albumin were reversed, and Gli3 expression was notably decreased in LX2 cells. Additionally, the target interaction between miR-152 and Gli3 was demonstrated. Finally, an miR-152 mimic was introduced into the rat model and additionally demonstrated that the changes in α-SMA, albumin and Gli3 expression levels were similar to the expression pattern in LX2 cells following miR-152 mimic transfection. These data provided insight into the potential function of miR-152 as an anti-fibrotic therapy through the modulation of Gli3.

Current Perspectives Regarding Stem Cell-Based Therapy for Liver Cirrhosis

Liver cirrhosis is a major cause of mortality and a common end of various progressive liver diseases. Since the effective treatment is currently limited to liver transplantation, stem cell-based therapy as an alternative has attracted interest due to promising results from preclinical and clinical studies. However, there is still much to be understood regarding the precise mechanisms of action. A number of stem cells from different origins have been employed for hepatic regeneration with different degrees of success. The present review presents a synopsis of stem cell research for the treatment of patients with liver cirrhosis according to the stem cell type. Clinical trials to date are summarized briefly. Finally, issues to be resolved and future perspectives are discussed with regard to clinical applications.

Swertiamarin Attenuates Experimental Rat Hepatic Fibrosis by Suppressing Angiotensin II-Angiotensin Type 1 Receptor-Extracellular Signal-Regulated Kinase Signaling

The rennin-angiotensin system (RAS) is crucial in hepatic fibrosis development, and therapies targeting this system may be a promising treatment for hepatic fibrosis. In this study, we investigated the effects of swertiamarin (Swe), an ethanol extract of Gentiana manshurica Kitag, on hepatic fibrosis and its underlying mechanisms through regulating RAS. Primary rat hepatic stellate cells (HSCs) were isolated and treated with angiotensin II (Ang II) with or without Swe and losartan. The proliferation and activation of HSCs were measured. Rat hepatic fibrosis was induced by intraperitoneal dimethylnitrosamine (DMN) injection for 4 weeks. Rats were treated with Swe or losartan from the third week until the end of the experiment. Hydroxyproline content in liver tissue was assayed with Jamall's method, and liver collagen deposition was visualized using Sirius red staining. RAS components were analyzed by Western blot, immunofluorescent staining, and real-time reverse-transcription polymerase chain reaction. The results showed that Swe significantly inhibited Ang II-induced HSC proliferation and activation. Swe also significantly suppressed DMN-induced α-smooth muscle actin production in rat livers and improved liver function. Swe partially inhibited Ang II-induced angiotensin type 1 receptor (AT1R) up-regulation and suppressed Ang II-induced extracellular signal-regulated kinase (ERK) and c-jun phosphorylation in HSCs. In the DMN-treated rats, Swe treatment significantly inhibited the plasma Ang II levels. DMN-induced AT1R up-regulation, and phosphorylation of ERK and c-jun in rat liver were also inhibited by Swe. In conclusion, Swe may attenuate hepatic fibrosis through inhibiting HSC activation by regulating the RAS.

Identifying Novel Targets for Treatment of Liver Fibrosis: What Can We Learn from Injured Tissues which Heal Without a Scar?

The liver is unique in that it is able to regenerate. This regeneration occurs without formation of a scar in the case of non-iterative hepatic injury. However, when the liver is exposed to chronic liver injury, the purely regenerative process fails and excessive extracellular matrix proteins are deposited in place of normal liver parenchyma. While much has been discovered in the past three decades, insights into fibrotic mechanisms have not yet lead to effective therapies; liver transplant remains the only cure for advanced liver disease. In an effort to broaden the collection of possible therapeutic targets, this review will compare and contrast the liver wound healing response to that found in two types of wound healing: scarless wound healing of fetal skin and oral mucosa and scar-forming wound healing found in adult skin. This review will examine wound healing in the liver and the skin in relation to the role of humoral and cellular factors, as well as the extracellular matrix, in this process. While several therapeutic targets are similar between fibrotic liver and adult skin wound healing, others are unique and represent novel areas for hepatic anti-fibrotic research. In particular, investigations into the role of hyaluronan in liver fibrosis and fibrosis resolution are warranted.

Noninvasive Markers to Assess Liver Fibrosis

Chronic liver disease represents a major public health problem, accounting for significant morbidity and mortality worldwide. Their prognosis and management greatly depends on the amount and progression of liver fibrosis with time and the risk of development of cirrhosis. Historically, liver biopsy was considered to be the gold standard for the detection of fibrosis. Nevertheless, liver biopsy is an invasive procedure that has limitations in terms of patient acceptance, risk-benefit ratio, cost-effectiveness, and its availability in various geographic regions. Moreover, it is a questionable gold standard due to significant sampling error and intraobserver and interobserver variability. These limitations have led to the development of noninvasive techniques for assessing the presence and the degree of liver fibrosis. This review aims to revise the most recent data from the literature about noninvasive methods useful in the evaluation of liver fibrosis.

Age-dependent development of liver fibrosis in Glmp (gt/gt) mice

Background

Mice lacking glycosylated lysosomal membrane protein (Glmp^gt/gt mice) have liver fibrosis as the predominant phenotype due to chronic liver injury. The Glmp^gt/gt mice grow and reproduce at the same rate as their wild-type siblings. Life expectancy is around 18 months.

Methods

Wild-type and Glmp^gt/gt mice were studied between 1 week and 18 months of age. Livers were analyzed using histological, immunohistochemical, biochemical, and qPCR analyses.

Results

It was shown that Glmp^gt/gt mice were not born with liver injury; however, it appeared shortly after birth as indicated by excess collagen expression, deposition of fibrous collagen in the periportal areas, and increased levels of hydroxyproline in Glmp^gt/gt liver. Liver functional tests indicated a chronic, mild liver injury. Markers of inflammation, fibrosis, apoptosis, and modulation of extracellular matrix increased from an early age, peaking around 4 months of age and followed by attenuation of these signals. To compensate for loss of hepatocytes, the oval cell compartment was activated, with the highest activity of the oval cells detected at 3 months of age, suggesting insufficient hepatocyte proliferation in Glmp^gt/gt mice around this age. Although constant proliferation of hepatocytes and oval cells maintained adequate hepatic function in Glmp^gt/gt mice, it also resulted in a higher frequency of liver tumors in older animals.

Conclusions

The Glmp^gt/gt mouse is proposed as a model for slowly progressing liver fibrosis and possibly as a model for a yet undescribed human lysosomal disorder.

Electronic supplementary material

The online version of this article (doi:10.1186/s13069-016-0042-4) contains supplementary material, which is available to authorized users.

Differential effects of hyaluronan synthase 3 deficiency after acute vs chronic liver injury in mice

Background

Hyaluronan (HA) is a ubiquitous extracellular matrix (ECM) glycosaminoglycan synthesized by three different enzymes, hyaluronan synthase (HAS)1, 2, and 3. HA synthesis mediated by HAS3 promotes inflammation and is pathogenic in animal models of human lung and intestinal disease. Liver fibrosis is a common endpoint to chronic liver injury and inflammation for which there is no cure. Although plasma HA is a commonly used biomarker for liver disease, if and how HA contributes to disease pathogenesis remains unclear. Here, we tested the hypothesis that HA synthesized by HAS3 enhances inflammation and fibrosis. To test this hypothesis, we exposed wild-type or Has3−/− mice to carbon tetrachloride (CCl₄) once (acute) or ten (chronic) times.

Results

HAS3-deficient mice exhibited increased hepatic injury and inflammatory chemokine production 48 h after acute CCl₄; this was associated with a threefold reduction in plasma HA levels and alterations in the proportions of specific molecular weight HA polymer pools. Hepatic accumulation of fibrosis-associated transcripts was also greater in livers from HAS3-deficient mice compared to controls after acute CCl₄ exposure. Surprisingly, fibrosis was not different between genotypes. Hepatic matrix metalloproteinase (MMP)13 mRNA and MMP13 activity was greater in livers from Has3-null mice after chronic CCl₄; this was prevented by a MMP13-specific inhibitor. Collectively, these data suggest that Has3, or more likely HA produced by HAS3, limits hepatic inflammation after acute injury and attenuates MMP13-mediated matrix metabolism after chronic injury.

Conclusions

These data suggest that HA should be investigated further as a novel therapeutic target for acute and chronic liver disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s13069-016-0041-5) contains supplementary material, which is available to authorized users.

Role of interleukin-1 and its antagonism of hepatic stellate cell proliferation and liver fibrosis in the Abcb4-/- mouse model

AIM: To study the interleukin-1 (IL-1) pathway as a therapeutic target for liver fibrosis in vitro and in vivo using the ATP-binding cassette transporter b4^-/- (Abcb4^-/-) mouse model.

METHODS: Female and male Abcb4^-/- mice from 6 to 13 mo of age were analysed for the degree of cholestasis (liver serum tests), extent of liver fibrosis (hydroxyproline content and Sirius red staining) and tissue-specific activation of signalling pathways such as the IL-1 pathway [quantitative polymerase chain reaction (qPCR)]. For in vivo experiments, murine hepatic stellate cells (HSCs) were isolated via pronase-collagenase perfusion followed by density gradient centrifugation using female mice. Murine HSCs were stimulated with up to 1 ng/mL IL-1β with or without 2.5 μg/mL Anakinra, an IL-1 receptor antagonist, respectively. The proliferation of murine HSCs was assessed via the BrdU assay. The toxicity of Anakinra was evaluated via the fluorescein diacetate hydrolysis (FDH) assay. In vivo 8-wk-old Abcb4^-/- mice with an already fully established hepatic phenotype were treated with Anakinra (1 mg/kg body-weight daily intraperitoneally) or vehicle and liver injury and liver fibrosis were evaluated via serum tests, qPCR, hydroxyproline content and Sirius red staining.

RESULTS: Liver fibrosis was less pronounced in males than in female Abcb4^-/- animals as defined by a lower hydroxyproline content (274 ± 64 μg/g vs 436 ± 80 μg/g liver, respectively; n = 13-15; P < 0.001; Mann-Whitney U-test) and lower mRNA expression of the profibrogenic tissue inhibitor of metalloproteinase-1 (TIMP) (1 ± 0.41 vs 0.66 ± 0.33 fold, respectively; n = 13-15; P < 0.05; Mann-Whitney U-test). Reduced liver fibrosis was associated with significantly lower levels of F4/80 mRNA expression (1 ± 0.28 vs 0.71 ± 0.41 fold, respectively; n = 12-15; P < 0.05; Mann-Whitney U-test) and significantly lower IL-1β mRNA expression levels (1 ± 0.38 vs 0.44 ± 0.26 fold, respectively; n = 13-15; P < 0.001; Mann-Whitney U-test). No gender differences in the serum liver parameters [bilirubin; alanine aminotransferase (ALT); aspartate aminotransferase and alkaline phosphatase (AP)] were found. In vitro, the administration of IL-1β resulted in a significant increase in HSC proliferation [0.94 ± 0.72 arbitrary units (A.U.) in untreated controls, 1.12 ± 0.80 A.U. at an IL-1β concentration of 0.1 ng/mL and 1.18 ± 0.73 A.U. at an IL-1β concentration of 1 ng/mL in samples from n = 6 donor animals; P < 0.001; analyses of variance (ANOVA)]. Proliferation was reduced significantly by the addition of 2.5 μg/mL Anakinra (0.81 ± 0.60 A.U. in untreated controls, 0.92 ± 0.68 A.U. at an IL-1β concentration of 0.1 ng/mL, and 0.91 ± 0.69 A.U. at an IL-1β concentration of 1 ng/mL; in samples from n = 6 donor animals; P < 0.001; ANOVA) suggesting an anti-proliferative effect of this clinically approved IL-1 receptor antagonist. The FDH assay showed this dose to be non-toxic in HSCs. In vivo, Anakinra had no effect on the hepatic hydroxyproline content, liver serum tests (ALT and AP) and pro-fibrotic (collagen 1α1, collagen 1α2, transforming growth factor-β, and TIMP-1) and anti-fibrotic [matrix metalloproteinase 2 (MMP2), MMP9 and MMP13] gene expression after 4 wk of treatment. Furthermore, the hepatic IL-1β and F4/80 mRNA expression levels were unaffected by Anakinra treatment.

CONCLUSION: IL-1β expression is associated with the degree of liver fibrosis in Abcb4^-/- mice and promotes HSC proliferation. IL-1 antagonism shows antifibrotic effects in vitro but not in Abcb4^-/- mice.

Ultrasonography for diagnosis of alcoholic cirrhosis in people with alcoholic liver disease

BACKGROUND

Heavy alcohol consumption causes alcoholic liver disease and is a causal factor of many types of liver injuries and concomitant diseases. It is a true systemic disease that may damage the digestive tract, the nervous system, the heart and vascular system, the bone and skeletal muscle system, and the endocrine and immune system, and can lead to cancer. Liver damage in turn, can present as multiple alcoholic liver diseases, including fatty liver, steatohepatitis, fibrosis, alcoholic cirrhosis, and hepatocellular carcinoma, with presence or absence of hepatitis B or C virus infection. There are three scarring types (fibrosis) that are most commonly found in alcoholic liver disease: centrilobular scarring, pericellular fibrosis, and periportal fibrosis. When liver fibrosis progresses, alcoholic cirrhosis occurs. Hepatocellular carcinoma occurs in 5% to 15% of people with alcoholic cirrhosis, but people in whom hepatocellular carcinoma has developed are often co-infected with hepatitis B or C virus.Abstinence from alcohol may help people with alcoholic disease in improving their prognosis of survival at any stage of their disease; however, the more advanced the stage, the higher the risk of complications, co-morbidities, and mortality, and lesser the effect of abstinence. Being abstinent one month after diagnosis of early cirrhosis will improve the chance of a seven-year life expectancy by 1.6 times. Liver transplantation is the only radical method that may change the prognosis of a person with alcoholic liver disease; however, besides the difficulties of finding a suitable liver transplant organ, there are many other factors that may influence a person's survival.Ultrasound is an inexpensive method that has been used for years in clinical practice to diagnose alcoholic cirrhosis. Ultrasound parameters for assessing cirrhosis in people with alcoholic liver disease encompass among others liver size, bluntness of the liver edge, coarseness of the liver parenchyma, nodularity of the liver surface, size of the lymph nodes around the hepatic artery, irregularity and narrowness of the inferior vena cava, portal vein velocity, and spleen size.Diagnosis of cirrhosis by ultrasound, especially in people who are asymptomatic, may have its advantages for the prognosis, motivation, and treatment of these people to decrease their alcohol consumption or become abstinent.Timely diagnosis of alcoholic cirrhosis in people with alcoholic liver disease is the cornerstone for evaluation of prognosis or choosing treatment strategies.

OBJECTIVES

To determine the diagnostic accuracy of ultrasonography for detecting the presence or absence of cirrhosis in people with alcoholic liver disease compared with liver biopsy as reference standard.To determine the diagnostic accuracy of any of the ultrasonography tests, B-mode or echo-colour Doppler ultrasonography, used singly or combined, or plus ultrasonography signs, or a combination of these, for detecting hepatic cirrhosis in people with alcoholic liver disease compared with liver biopsy as a reference standard, irrespective of sequence.

SEARCH METHODS

We performed searches in The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Hepato-Biliary Group Diagnostic Test Accuracy Studies Register, The Cochrane Library (Wiley), MEDLINE (OvidSP), EMBASE (OvidSP), and the Science Citation Index Expanded to 8 January 2015. We applied no language limitations.We screened study references of the retrieved studies to identify other potentially relevant studies for inclusion in the review and read abstract and poster publications.

SELECTION CRITERIA

Three review authors independently identified studies for possible inclusion in the review. We excluded references not fulfilling the inclusion criteria of the review protocol. We sent e-mails to study authors.The included studies had to evaluate ultrasound in the diagnosis of hepatic cirrhosis using only liver biopsy as the reference standard.The maximum time interval of investigation with liver biopsy and ultrasonography should not have exceeded six months. In addition, ultrasonography could have been performed before or after liver biopsy.

DATA COLLECTION AND ANALYSIS

We followed the Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy.

MAIN RESULTS

The review included two studies that provided numerical data regarding alcoholic cirrhosis in 205 men and women with alcoholic liver disease. Although there were no applicability concerns in terms of participant selection, index text, and reference standard, we judged the two studies at high risk of bias. Participants in both studies had undergone both liver biopsy and ultrasonography investigations. The studies shared only a few comparable clinical signs and symptoms (index tests).We decided to not perform a meta-analysis due to the high risk of bias and the high degree of heterogeneity of the included studies.

AUTHORS' CONCLUSIONS

As the accuracy of ultrasonography in the two included studies was not informative enough, we could not recommend the use of ultrasonography as a diagnostic tool for liver cirrhosis in people with alcoholic liver disease. In order to be able to answer the review questions, we need diagnostic ultrasonography prospective studies of adequate sample size, enrolling only participants with alcoholic liver disease.The design and report of the studies should follow the Standards for Reporting of Diagnostic Accuracy. The sonographic features, with validated cut-offs, which may help identify clinical signs used for diagnosis of fibrosis in alcoholic liver disease, should be carefully selected to achieve maximum diagnostic accuracy on ultrasonography.

Sirtuin 3 (SIRT3) Regulates α-Smooth Muscle Actin (α-SMA) Production through the Succinate Dehydrogenase-G Protein-coupled Receptor 91 (GPR91) Pathway in Hepatic Stellate Cells

Sirtuin 3 (SIRT3) is an NAD(+)-dependent protein deacetylase. Recent studies have shown that SIRT3 expression is decreased in nonalcoholic fatty liver disease (NAFLD). Moreover, SIRT3 is a key regulator of succinate dehydrogenase (SDH), which catalyzes the oxidation of succinate to fumarate. Increased succinate concentrations and the specific G protein-coupled receptor 91 (GPR91) are involved in the activation of hepatic stellate cells (HSCs). In this study, we aimed to establish whether SIRT3 regulated the SDH activity, succinate, and GPR91 expression in HSCs and an animal model of NAFLD. Our goal was also to determine whether succinate released from hepatocytes regulated HSC activation. Inhibiting SIRT3 using SIRT3 siRNA exacerbated HSC activation via the SDH-succinate-GPR91 pathway, and SIRT3 overexpression or honokiol treatment attenuated HSC activation in vitro In isolated liver and HSCs from methionine- and choline-deficient (MCD) diet-induced NAFLD, the expression of SIRT3 and SDH activity was decreased, and the succinate concentrations and GPR91 expression were increased. Moreover, we found that GPR91 knockdown or resveratrol treatment improved the steatosis in MCD diet-fed mice. This investigation revealed a novel mechanism of the SIRT3-SDH-GPR91 cascade in MCD diet-induced HSC activation in NAFLD. These findings highlight the biological significance of novel strategies aimed at targeting SIRT3 and GPR91 in HSCs with the goal of improving NAFLD treatment.

Assessment of fibrotic tissue and microvascular architecture by in-line phase-contrast imaging in a mouse model of liver fibrosis

PURPOSE

To explore the value of in-line phase-contrast imaging with computed tomography (ILPCI-CT) by synchrotron radiation (SR) for liver fibrosis.

MATERIALS AND METHODS

Liver fibrosis models were set up in 13 BALB/c mice by peritoneal injections of thioacetamide and evaluated by ILPCI-CT. Histological staging was used to categorize liver fibrosis into normal, mild fibrosis and advanced fibrosis groups. Microvessel density (MVD), the ratio of total vessel length to volume (L/V), the ratio of total number of branching points to liver volume (P/V) and the distribution of vessel diameter were assessed.

RESULTS

The CT images showed slightly high-density shadows around the portal tracts in the fibrosis group. Three-dimensional reconstruction can detect vascular and nodular changes on the surface of fibrotic livers. The MVDs between the three groups were significantly different (P = 0.024). L/V was significantly different between the three groups (P = 0.014). There was a positive correlation between MVD and P/V.

CONCLUSION

Fibrous material can be detected by ILPCI-CT even in the early stage of fibrosis. MVD, L/V, P/V and the distribution of vessel diameter were consistent with fibrosis-related angiogenesis progress. Three-dimensional reconstruction is a promising method to visualize morphological changes of the fibrotic liver.

KEY POINTS

• ILPCI-CT can detect fibrous material even in the early stage of liver fibrosis. • MVD, L/V, P/V, and the distribution of vascular diameter reflect pathological angiogenesis. • 3D reconstruction could be a promising approach for detecting liver fibrosis.

Inhibition of liver fibrosis using vitamin A-coupled liposomes to deliver matrix metalloproteinase-2 siRNA in vitro

Hepatic fibrosis is a common form of wound healing in response to chronic liver injuries and can lead to more serious complications, including mortality. It is well-established that hepatic stellate cells (HSCs) are central mediators of hepatic fibrosis, and matrix metalloproteinase-2 (MMP-2) is important in the formation of liver fibrosis. In addition, HSCs are the primary cells secreting MMP-2 and extracellular matrix, therefore, there has been increasing interest in developing agents with high selectivity towards HSCs. However, no clinical drugs based on MMP-2, directed against HSCs, have been used to prevent fibrosis. Following consideration of the abundant vitamin A (VitA) receptors expressed on the cellular membrane of HSCs, the present study constructed VitA-coupled liposomes (VitA-lips) using dicyclohexylcarbodiimide-1, 3-diaminopentane condensation, rotatory film processing and ultrasonic oscillation. The results revealed that the liposomes exhibited low cytotoxicity and a suitable binding ability to MMP-2 small interference (si)RNA. Furthermore, the liposomes effectively delivered MMP-2 siRNA to the HSC-T6 cells. When HSCs were treated with the liposomes carrying MMP-2 siRNA (VitA-lip-MMP-2 siRNA), the mRNA expression and activity of MMP-2, and the protein expression levels of α-smooth muscle actin and type I collagen were significantly reduced. These results suggested that inhibition of the expression of MMP-2 in HSC-T6 cells may contribute to preventing hepatic fibrosis, and provided experimental support to the development of specific drugs against MMP-2 to prevent fibrogenesis in chronic liver disease.

Transient elastography for diagnosis of stages of hepatic fibrosis and cirrhosis in people with alcoholic liver disease

BACKGROUND

The presence and progression of hepatic (liver) fibrosis into cirrhosis is a prognostic variable having impact on survival in people with alcoholic liver disease. Liver biopsy, although an invasive method, is the recommended 'reference standard' for diagnosis and staging of hepatic fibrosis in people with liver diseases. Transient elastography is a non-invasive method for assessing and staging hepatic fibrosis.

OBJECTIVES

To determine the diagnostic accuracy of transient elastography for diagnosis and staging hepatic fibrosis in people with alcoholic liver disease when compared with liver biopsy. To identify the optimal cut-off values for differentiating the five stages of hepatic fibrosis.

SEARCH METHODS

The Cochrane Hepato-Biliary Group Controlled and Diagnostic Test Accuracy Studies Registers, The Cochrane Library, MEDLINE (OvidSP), EMBASE (OvidSP), and the Science Citation Index Expanded (last search August 2014).

SELECTION CRITERIA

Diagnostic cohort and diagnostic case-control study designs that assessed hepatic fibrosis in participants with alcoholic liver disease with transient elastography and liver biopsy, irrespective of language or publication status. The study participants could be of any sex and ethnic origin, above 16 years old, hospitalised or managed as outpatients. We excluded participants with viral hepatitis, autoimmunity, metabolic diseases, and toxins.

DATA COLLECTION AND ANALYSIS

We followed the guidelines in the draft Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy.

MAIN RESULTS

Five retrospective and nine prospective cohort studies with 834 participants provided data for the review analyses. Authors of seven of those studies sent us individual participant data. The risk of bias in the included studies was high in all but three studies. We could identify no serious concerns regarding the applicability of the studies in answering the main study question of our review, namely to use transient elastography to diagnose hepatic fibrosis. We could not identify the optimal cut-off values for the fibrosis stages. The definition of the diagnosis of alcoholic liver disease was not provided in one study and was not clearly defined in two studies, but it was clear in the remaining 11 studies. The study authors used different liver stiffness cut-off values of transient elastography for the hepatic fibrosis stages.There was only one study (103 participants) with data on hepatic fibrosis stage F1 or worse, with a cut-off of 5.9 kPa, and reporting sensitivity of 0.83 (95% confidence interval (CI) 0.74 to 0.90) and specificity of 0.88 (95% CI 0.47 to 1.00). The summary sensitivity and specificity of transient elastography for F2 or worse (seven studies with 338 participants and with cut-offs around 7.5 kPa (range 7.00 to 7.8 kPa)) were 0.94 and 0.89 with LR+ 8.2 and LR- 0.07, which suggests that transient elastography could be useful to rule out the presence of significant hepatic fibrosis, thus avoiding liver biopsy.Due to the wide range of cut-off values (from 8.0 to 17.0 kPa) found in the 10 studies with 760 participants with hepatic fibrosis F3 or worse, we fitted a hierarchical summary receiver operating characteristic (HSROC) model and estimated a summary ROC (SROC) curve. The sensitivity of the 10 studies varied from 72% to 100% and the specificity from 59% to 89%. We performed an additional analysis by including the studies with a cut-off value of around and equal to 9.5 kPa (range 8.0 to 11.0 kPa). The summary sensitivity and specificity of transient elastography (eight studies with 564 participants) were 0.92 and 0.70 with LR+ 3.1 and LR- 0.11, which suggests that transient elastography could also be useful to rule out the presence of severe hepatic fibrosis (F3 or worse), avoiding liver biopsy. We carried out a sensitivity analysis by considering only the studies with a cut-off value equal to 9.5 kPa and the result did not differ.We performed an HSROC analysis and reported an SROC curve for hepatic fibrosis stage F4 (cirrhosis). The HSROC analysis suggested that when the cut-off value changes, there is a wide variation in specificity and a more limited variation in sensitivity. We performed an additional analysis with the studies with the most commonly used cut-off value of 12.5 kPa. The summary sensitivity and specificity of transient elastography (seven studies with 330 participants) were 0.95 and 0.71 with LR+ 3.3 and LR- 0.07, which again suggests that transient elastography could be useful to rule out the presence of cirrhosis, avoiding liver biopsy.

AUTHORS' CONCLUSIONS

We identified a small number of studies with a few participants and were unable to include several studies, which raises the risk of outcome reporting bias. With these caveats in mind, transient elastography may be used as a diagnostic method to rule out liver cirrhosis (F4) in people with alcoholic liver disease when the pre-test probability is about 51% (range 15% to 79%). Transient elastography may also help in ruling out severe fibrosis (F3 or worse). Liver biopsy investigation remains an option if the certainty to rule in or rule out the stage of hepatic fibrosis or cirrhosis remains insufficient after a clinical follow-up or any other non-invasive test considered useful by the clinician.The proposed cut-off values for the different stages of hepatic fibrosis may be used in clinical practice, but caution is needed, as those values reported in this review are only the most common cut-off values used by the study authors. The best cut-off values for hepatic fibrosis in people with alcoholic liver disease could not be established yet.In order to diagnose correctly the stage of hepatic fibrosis in people with alcoholic liver disease using transient elastography assessment, the studies should consider a single aetiology. Hepatic fibrosis should be diagnosed with both transient elastography and liver biopsy and in this sequence, and transient elastography cut-off values should be pre-specified and validated. The time interval between the two investigations should not exceed three months, which is the interval mainly valid for people without cirrhosis, and assessment of results should be properly blinded. Only studies with low risk of bias, fulfilling the Standards for Reporting of Diagnostic Accuracy may answer the review question.

Use of mesenchymal stem cells to treat liver fibrosis: Current situation and future prospects

Progressive liver fibrosis is a major health issue for which no effective treatment is available, leading to cirrhosis and orthotopic liver transplantation. However, organ shortage is a reality. Hence, there is an urgent need to find alternative therapeutic strategies. Cell-based therapy using mesenchymal stem cells (MSCs) may represent an attractive therapeutic option, based on their immunomodulatory properties, their potential to differentiate into hepatocytes, allowing the replacement of damaged hepatocytes, their potential to promote residual hepatocytes regeneration and their capacity to inhibit hepatic stellate cell activation or induce their apoptosis, particularly via paracrine mechanisms. The current review will highlight recent findings regarding the input of MSC-based therapy for the treatment of liver fibrosis, from in vitro studies to pre-clinical and clinical trials. Several studies have shown the ability of MSCs to reduce liver fibrosis and improve liver function. However, despite these promising results, some limitations need to be considered. Future prospects will also be discussed in this review.

Nogo-B: A potential indicator for hepatic cirrhosis and regulator in hepatic stellate cell activation

AIM

To evaluate plasma Nogo-B levels in liver cirrhotic patients and declare a novel molecular basis by which Nogo-B modulates hepatic stellate cell (HSC) activation.

METHODS

Plasma Nogo-B levels from liver cirrhotic patients were detected by enzyme-linked immunosorbent assay. Rat primary HSC were culture activated or stimulated with transforming growth factor (TGF)-β. Activated HSC were transfected for 48 h with Nogo-B shRNA to inhibit Nogo-B expression. Gene expressions of Nogo-B, α-smooth muscle actin (SMA), collagen type I, TGF-β, endoplasmic reticulum (ER) stress key molecules, including C/EBP homologous protein (CHOP), glucose-regulated protein 78 (GRP78), activating transcription factor (ATF)4, ATF6, X-box binding protein 1 (Xbp-1) and calnexin, and the marker of autophagy beclin 1, were detected by quantitative reverse transcription polymerase chain reaction. The protein expressions of Nogo-B, α-SMA, collagen type I, CHOP, GRP78 and the marker of autophagy LC3B were evaluated by western blot.

RESULTS

Liver cirrhotic patients showed a much higher level of plasma Nogo-B compared with the healthy controls. Nogo-B expression and ER stress could be induced during the process of cultured HSC activation. TGF-β treatment increased Nogo-B expression time- and dose-dependently. Knockdown of Nogo-B in HSC reduced the activation of HSC. After Nogo-B gene knockdown, there was a decline of expression of ER stress markers and autophagic markers. Agonist or antagonist of ER stress could regulate autophagy level.

CONCLUSION

Circulating Nogo-B may be an effective indicator for liver cirrhosis. Nogo-B inhibition could diminish HSC activation, in which alleviating ER stress may be one of the mechanisms, suggesting a potential approach to interference Nogo-B in liver fibrosis.