Liver cirrhosis

iNOS expression in vascular resident macrophages contributes to circulatory dysfunction of splanchnic vascular smooth muscle contractions in portal hypertensive rats

Portal hypertension, a major complication of cirrhosis, is caused by both increased portal blood flow due to arterial vasodilation and augmented intrahepatic vascular resistance due to sinusoidal constriction. In this study, we examined the possible involvement of resident macrophages in the tone regulation of splanchnic blood vessels using bile duct ligated (BDL) portal hypertensive rats and an in vitro organ culture method. In BDL cirrhosis, the number of ED2-positive resident macrophages increased by two- to fourfold in the vascular walls of the mesenteric artery and extrahepatic portal vein compared with those in sham-operated rats. Many ED1-positive monocytes were also recruited into this area. The expression of inducible nitric oxide (NO) synthase (iNOS) mRNA was increased in the vascular tissues isolated from BDL rats, and accordingly, nitrate/nitrite production was increased. Immunohistochemistry revealed that iNOS was largely expressed in ED1-positive and ED2-positive cells. We further analyzed the effect of iNOS expression on vascular smooth muscle contraction using an in vitro organ culture system. iNOS mRNA expression and nitrate production significantly increased in vascular tissues (without endothelium) incubated with 1 μg/ml lipopolysaccharide (LPS) for 6 h. Immunohistochemistry indicated that iNOS was largely expressed in ED2-positive resident macrophages. α-Adrenergic-stimulated contractility of the mesenteric artery was greatly suppressed by LPS treatment and was restored by N(G)-nitro-L-arginine methyl ester (NO synthase inhibitor); in contrast, portal vein contractility was largely unaffected by LPS. Sodium nitroprusside (NO donor) and 8-bromo-cGMP showed greater contractile inhibition in the mesenteric artery than in the portal vein with decreasing myosin light chain phosphorylation. In the presence of an α-adrenergic agonist, the mesenteric artery cytosolic Ca(2+) level was greatly reduced by sodium nitroprusside; however, the portal vein Ca(2+) level was largely unaffected. These results suggest that the induction of iNOS in monocytes/macrophages contributes to a hypercirculatory state in the cirrhosis model rat in which the imbalance of the responsiveness of visceral vascular walls to NO (mesenteric artery >> portal vein) may account for the increased portal venous flow in portal hypertension.

Randomized clinical trial of splenic radiofrequency ablation versus splenectomy for severe hypersplenism

BACKGROUND

Radiofrequency ablation (RFA) is a relatively new treatment for hypersplenism. The results of a randomized clinical trial comparing RFA and splenectomy with 5 years of follow-up are reported.

METHODS

Fifty-seven patients with hypersplenism due to liver cirrhosis were assigned randomly (in a 1 : 2 ratio) to splenectomy (19 patients) or RFA (38). The RFA group was subdivided according to the percentage of the spleen ablated: less than 50 per cent (9 patients), 50-70 per cent (18) or over 70 per cent (11). Routine blood tests were performed before and after operation, and total spleen volume and ablated volume were measured by contrast-enhanced computed tomography. The primary endpoint of the trial was recurrence of hypersplenism, assessed as platelet and white cell counts, at 5 years after surgery.

RESULTS

White cell and platelet counts increased rapidly after intervention in both groups. By 36 months after operation peripheral platelet and white cell counts had decreased significantly in the RFA group compared with the splenectomy group, and declined to baseline levels by 48 months. Hypersplenism recurred after 6 months in patients with less than 50 per cent of the spleen ablated. Blood cell count in the splenectomy group and in patients with more than 50 per cent of the spleen ablated decreased with time after operation, but to levels that remained significantly higher than those before operation (P < 0·050). Splenic volume reached its nadir 12 months after RFA and then increased with time.

CONCLUSION

Splenic RFA represents an attractive alternative treatment for hypersplenism induced by liver cirrhosis, particularly when more than 50 per cent of the spleen is ablated.

Tolerability of everolimus-based immunosuppression in maintenance liver transplant recipients

BACKGROUND

The aim of this study was to evaluate the tolerability of the conversion from calcineurin inhibitor (CNI) to everolimus (ERL) in maintenance liver transplant (LT) recipients.

METHODS

From January 2005 to March 2008, ERL was introduced after LT as maintenance immunosuppressive therapy because of (i) de novo or recurrent cancer after LT, (ii) pre-existing liver carcinoma on the liver explant or (iii) CNI toxicity. CNI dosage was progressively reduced until discontinuation.

RESULTS

The study population included 94 patients, of mean age 57 ± 10. The mean delay between LT and ERL introduction was 5 ± 5 yr. After a mean follow-up of 12 ± 7 months, 70% of the patients did present at least one side effect. The mean trough level of ERL was 6 μg/L at the end of follow-up. Main side effects included hyperlipidemia (37%), dermatitis (19%), mucositis (15%), and proteinuria (18%). Biopsy-proven acute rejection occurred in 9% of patients. Global ERL discontinuation rate was 21% (16% because of side effects).

CONCLUSIONS

The results of our experience indicate that conversion to ERL is associated with adverse effects in 70% of patients leading to drug discontinuation in 16% (and amenable to dose reduction in the remainders). Longer follow-up periods are necessary to capture the impact of ERL fully on renal function and survival in cancer patients.

Hepatitis C virus genotype 3 and the risk of severe liver disease in a large population of drug users in France

Although risk factors for cirrhosis in chronic hepatitis C virus (HCV) infection have been identified, the role of HCV-genotype 3 remains controversial, and limited data are available in drug users. The aim of the study was to assess risk factors for severe liver disease (cirrhosis/hepatocellular carcinoma) in HCV-infected drug users between 2001 and 2007 in France. Patients who reported drug use and who had been referred for HCV infection to hepatology centers from a national surveillance system were identified. The severity of liver disease was assessed clinically and histologically (Metavir score). Factors associated with severe liver disease were analyzed after estimating missing values by multiple imputation (MI). Of the 4,065 drug users naive to anti-HCV treatment who were referred to the 26 participating centers, 8.0% had severe liver disease, 25.7% were infected with HCV-genotype 3. Factors associated independently with an increased risk of severe liver disease were HCV-genotype 3 (adjusted odds ratio, multiple imputation (aOR(MI)) = 1.6, [95% confidence interval, 95% CI: 1.2-2.1]), HIV infection (aOR(MI) = 1.8, [1.2-2.8]), male sex (aOR(MI) = 2.0, [1.4-2.8]), age over 40 years (aOR(MI) = 2.1, [1.6-2.9]), history of excessive alcohol consumption (aOR(MI) = 2.8, [2.1-3.7]), and duration of infection ≥18 years (aOR(MI) = 2.9, [2.0-4.3]). This analysis shows that HCV-genotype 3 is associated with severe liver disease in drug users, independently of age, sex, duration of infection, alcohol consumption, and co-infection with HIV. These results are in favor of earlier treatment for drug users infected with HCV- genotype 3 and confirm the need for concomitant care for excessive alcohol consumption.

Viral factors induce Hedgehog pathway activation in humans with viral hepatitis, cirrhosis, and hepatocellular carcinoma

Hedgehog (Hh) pathway activation promotes many processes that occur during fibrogenic liver repair. Whether the Hh pathway modulates the outcomes of virally mediated liver injury has never been examined. Gene-profiling studies of human hepatocellular carcinomas (HCCs) demonstrate Hh pathway activation in HCCs related to chronic infection with hepatitis B virus (HBV) or hepatitis C virus (HCV). Because most HCCs develop in cirrhotic livers, we hypothesized that Hh pathway activation occurs during fibrogenic repair of liver damage due to chronic viral hepatitis, and that Hh-responsive cells mediate disease progression and hepatocarciongenesis in chronic viral hepatitis. Immunohistochemistry and qRT-PCR analysis were used to analyze Hh pathway activation and identify Hh-responsive cell types in liver biopsies from 45 patients with chronic HBV or HCV. Hh signaling was then manipulated in cultured liver cells to directly assess the impact of Hh activity in relevant cell types. We found increased hepatic expression of Hh ligands in all patients with chronic viral hepatitis, and demonstrated that infection with HCV stimulated cultured hepatocytes to produce Hh ligands. The major cell populations that expanded during cirrhosis and HCC (ie, liver myofibroblasts, activated endothelial cells, and progenitors expressing markers of tumor stem/initiating cells) were Hh responsive, and higher levels of Hh pathway activity associated with cirrhosis and HCC. Inhibiting pathway activity in Hh-responsive target cells reduced fibrogenesis, angiogenesis, and growth. In conclusion, HBV/HCV infection increases hepatocyte production of Hh ligands and expands the types of Hh-responsive cells that promote liver fibrosis and cancer.

Renal and circulatory dysfunction in cirrhosis: current management and future perspectives

Chronic liver diseases are amongst the top leading causes of death in Europe as well as in other areas of the world. Chronic liver diseases are characterized by unrelenting progression of liver inflammation and fibrosis over a prolonged period of time, usually more than 20 years, which may eventually lead to cirrhosis. Advanced cirrhosis leads to a complex syndrome of chronic liver failure which involves many different organs besides the liver, including the brain, heart and systemic circulation, adrenal glands, lungs, and kidneys. The high morbidity and mortality secondary to chronic liver failure is due to complications related to the dysfunction of these organs, either alone or, more frequently, in combination. Understanding the mechanisms leading to organ dysfunction is crucial to the development of strategies for treatment and prevention of complications of cirrhosis. This article reviews our current knowledge, as well as future perspectives, on the management of circulatory and renal dysfunction in chronic liver failure.

Cardiac cirrhosis: a rare manifestation of an uncorrected primum atrial septal defect

Atrial septal defects constitute the second most common cardiac congenital abnormality. These defects when undiagnosed during childhood, present in adulthood with symptoms of right heart failure. We describe a case of uncorrected ostium primum atrial septal defect that presented as liver failure in a 43-year-old woman. The patient was found to have liver cirrhosis and a complete work-up of hepatic causes for cirrhosis was negative. Further examination revealed an atrial primum septal defect. Liver cirrhosis in this patient was thought to be secondary to chronic congestion from the right heart failure resulting from the atrial septal defect. Although right heart failure is a known cause of cirrhosis, liver cirrhosis resulting specifically from an atrial septal defect is uncommon. In fact, an ostium primum atrial septal defect presenting as liver cirrhosis has not been well described. We present such a case to highlight this manifestation of atrial septal defect and also to reiterate that cardiac causes should always be considered in the differential diagnosis whenever a patient presents with liver cirrhosis.

HIV and HCV cooperatively promote hepatic fibrogenesis via induction of reactive oxygen species and NFkappaB

HIV/HCV coinfection leads to accelerated hepatic fibrosis progression, with higher rates of cirrhosis, liver failure, and liver death than does HCV mono-infection. However, the profibrogenic role of HIV on hepatocytes and hepatic stellate cells (HSC) has not been fully clarified. We hypothesized that HIV, HCV induce liver fibrosis through altered regulation of the production of extracellular matrix and matrix metalloproteinases. We examined the fibrogenesis- and fibrolysis-related gene activity in LX2 HSC and Huh7.5.1 cells in the presence of inactivated CXCR4 and CCR5 HIV, as well as HCV JFH1 virus. The role of reactive oxygen species (ROS) upon fibrosis gene expression was assessed using the ROS inhibitor. Fibrosis-related transcripts including procollagen α1(I) (CoL1A), TIMP1, and MMP3 mRNA were measured by qPCR. TIMP1 and MMP3 protein expression were assessed by ELISA. We found that inactivated CXCR4 HIV and CCR5 HIV increased CoL1A, and TIMP1 expression in both HSC and Huh7.5.1 cells; the addition of JFH1 HCV further increased CoL1A and TIMP1 expression. CXCR4 HIV and CCR5 HIV induced ROS production in HSC and Huh7.5.1 cells which was further enhanced by JFH1 HCV. The ROS inhibitor DPI abrogated HIV-and HCV-induced CoL1A and TIMP1 expression. HIV and HCV-induced CoL1A and TIMP1 expression were also blocked by NFκB siRNA. Our data provide further evidence that HIV and HCV independently regulate hepatic fibrosis progression through the generation of ROS; this regulation occurs in an NFκB-dependent fashion. Strategies to limit the viral induction of oxidative stress are warranted to inhibit fibrogenesis.

Multivessel coronary artery disease predicts mortality, length of stay, and pressor requirements after liver transplantation

The optimal preoperative cardiac evaluation strategy for patients with end-stage liver disease (ESLD) undergoing liver transplantation remains unknown. Patients are frequently referred for cardiac catheterization, but the effects of coronary artery disease (CAD) on posttransplant mortality are also unknown. We sought to determine the contribution of CAD and multivessel CAD in particular to posttransplant mortality. We performed a retrospective study of ESLD patients undergoing cardiac catheterization before liver transplant surgery between August 1, 2004 and August 1, 2007 to determine the effects of CAD on outcomes after transplantation. Among 83 patients who underwent left heart catheterization, 47 underwent liver transplantation during the follow-up period. Twenty-one of all ESLD patients who underwent liver transplantation (45%) had CAD. Fifteen of the transplant patients with CAD (71%) had multivessel disease. Among transplant patients, the presence of multivessel CAD (versus no CAD) was predictive of mortality (27% versus 4%, P = 0.046), increased length of stay (22 versus 15 days, P = 0.050), and postoperative pressor requirements (27% versus 4%, P = 0.029). Interestingly, neither the presence of any CAD nor the severity of stenosis in any single coronary artery predicted mortality. Furthermore, none of the traditional clinical predictors (age, gender, diabetes, creatinine, ejection fraction, and Model for End-Stage Liver Disease score) were predictive of mortality among transplant recipients. In conclusion, multivessel CAD is associated with higher mortality after liver transplantation when it is documented angiographically before transplantation, even in the absence of severe coronary artery stenosis. This study provides preliminary evidence showing that there may be significant prognostic value in coronary angiography as a part of the pretransplant workup.

Biomarkers of liver injury for hepatitis clinical trials: a meta-analysis of longitudinal studies

BACKGROUND

Liver biopsy and virological end points are standard references for assessing the effect of viral hepatitis treatments. We aimed to review evidence-based published data of biomarkers that have been validated as non-invasive alternatives to biopsy as end points for HBV and HCV infection trials.

METHODS

Studies were included if there were at least two repeated estimates of fibrosis per patient using biomarkers with at least two studies and a control group. Meta-analysis of the percentage of fibrosis progression per year (pFPy) was performed.

RESULTS

Two biomarkers were included, FibroTest and liver stiffness measurement (LSM; FibroScan. A total of 1,413 patients with chronic hepatitis C (11 populations) and 772 with chronic hepatitis B (6 populations) were analysed. In a comparison of HCV patients with controls, the FibroTest pFPy was -18% (95% confidence interval [CI] -23--14; P<0.001) in treated patients and the LSM pFPy was -15% (95% CI -28--1; P=0.01), both with differences according to virological responses. In HBV patients, there was a significant decrease of the pFPy only in patients with baseline advanced fibrosis (mean difference -5% [95% CI -10--0.1]; P=0.02). In patients with advanced fibrosis, stratified by virological response, there were similar differences between pFPy estimated either using FibroTest or biopsy, both in HCV and HBV infections. Repeated LSM in HBV patients had an early variability related to necroinflammatory activity.

CONCLUSIONS

In patients with chronic hepatitis C and B, the treatment effect on fibrosis progression rate was similarly estimated using FibroTest or biopsy. The same concordance was observed for FibroScan but with a possible overestimation of the fibrosis regression during the first weeks of treatment.

A natural process of cirrhosis resolution and deceleration of liver regeneration after thioacetamide withdrawal in a rat model

Characteristics of thioacetamide (TAA)-induced liver cirrhosis in rat was observed for 120 days after TAA withdrawal as part of the radiobiological study of partial liver irradiation on TAA-induced cirrhotic rats. The natural process focused on cirrhosis and regeneration was recorded as a baseline condition for the interpretation of the outcome of the partial liver irradiation study. Cirrhosis in rats was successfully induced by drinking 0.03% TAA water orally for 29 weeks with a modeling rate of 96%. After establishment of the cirrhosis model, the rats were observed for 120 days upon TAA withdrawal to investigate the dynamic changes of cirrhosis and regeneration. The following characteristics were observed: (1) Histological changes; (2) Liver functions; (3) Cirrhosis: trichrome stain, quantification of hydroxyproline in hydrolysed liver tissue and TGF-β1; (4) Liver regeneration: liver index, hepatocyte mitotic index (MI), hepatocyte proliferation index (PI) by flow cytometry, PCNA labeling index (LI) by IHC and expression of PCNA mRNA; and (5) Growth factors: serum HGF, VEGF, TGF-α, and IL-6. After TAA withdrawal, gradual improvement in liver functions was noted with decreases of ALT, AST, and ALP, and increase of PA. The resolution of cirrhosis was evident by histological improvement with attenuation of collagen fiber and decrease of TGF-β1 IHC index, and also decrease of trichrome stain and hydroxyproline content. However, cirrhosis was still existed on 120 days after TAA withdrawal. Significant deceleration of liver regeneration was demonstrated with TAA withdrawal, evidenced by decrease of MI and PI, reduced expression of PCNA mRNA and PCNA LI. In conclusion, upon TAA withdrawal hepatic cirrhosis was continuously resolved, but persisted up to 120 days, and liver regeneration was significantly decelerated.

Assessment of hepatic fibrosis by analysis of the dynamic behaviour of microbubbles during contrast ultrasonography

BACKGROUND/AIMS

Microbubble behaviour from the portal vein to the liver parenchyma may reflect haemodynamic changes because of hepatic fibrosis. The aim of this study was to determine the efficacy of contrast-enhanced ultrasound (US) with Sonazoid™ for the assessment of the grade of hepatic fibrosis.

METHODS

This prospective study evaluated 117 patients with chronic liver disease (chronic hepatitis 85; cirrhosis 32) and 34 controls. All subjects received both contrast-enhanced US with Sonazoid™ for 1 min after the agent injection and subsequent liver biopsy. Flow velocity and flow volume in the right portal vein, onset time of contrast enhancement in the right hepatic artery and right portal vein, maximum intensity ratio between the intra-hepatic portal vein and liver parenchyma, and time interval between the onset time and the time of maximum intensity ratio were compared with the pathological findings.

RESULTS

Among the evaluated parameters, time interval between the onset time and the time of maximum intensity ratio showed the closest relationship with the grade of hepatic fibrosis: 4.21 ± 1.32 for controls (n=34), 5.58 ± 1.39 for F1 (n=31), 6.79 ± 1.77 for F2 (n=28), 8.85 ± 1.97 for F3 (n=26) and 14.3 ± 3.49 for cirrhosis (n=32); controls vs. F2, P=0.0004; F1 vs. F3, P<0.0001; F2 vs. F3, P=0.0177; F3 vs. cirrhosis, P<0.0001. The areas under the receiver operating characteristic curves of the time interval were 0.94, 0.96 and 0.98 for the diagnosis of marked fibrosis (≥F2), advanced fibrosis (≥F3) and cirrhosis respectively.

CONCLUSIONS

Contrast-enhanced US with Sonazoid™ may be a promising method for the indirect evaluation of hepatic fibrosis.

Diabetes mellitus and hepatocellular carcinoma: Comparison of Chinese patients with and without HBV-related cirrhosis

AIM: To determine the role of diabetes mellitus (DM) and other associated factors in Chinese hepatocellular carcinoma (HCC) patients with cirrhosis, compared with those HCC patients without cirrhosis, in the single setting of hepatitis B virus (HBV) infection, after other known concomitant diseases were excluded.

METHODS: A total of 482 patients, treated at the China-Japan Friendship Hospital, Ministry of Health (Beijing, China), in the period January 2003 to June 2009, and with a hospital discharge diagnosis of HCC, were included. Demographic, clinical, laboratory, metabolic and instrumental features were analyzed.

RESULTS: Of the total, 310 patients were diagnosed with HBV infection and, following the inclusion and exclusion criteria, 224 were analyzed, including 122 patients (54.5%) with cirrhosis (the case group) and 102 patients without cirrhosis (the control group). Twenty-seven patients (12.1%) were diabetic, including 19 in the case group and 8 in the control group (19/122 = 15.6% vs 8/102 = 7.8%, P = 0.077). Thirty-one possible relevant parameters were compared by univariate analysis, and 9 variables were selected for multivariable analysis, including DM (P = 0.077), past history of HBV infection (P = 0.005), total bilirubin (P < 0.001), albumin level (P < 0.001), international normalized ratio (INR) (P < 0.001), alanine aminotransferase (P = 0.050), platelet (P < 0.001), total cholesterol (P = 0.047), and LDL cholesterol (P = 0.002) levels. Diabetes showed a statistical difference by multivariable analysis [odds ratio (OR) 4.88, 95% confidence interval (CI): 1.08-21.99, P = 0.039], although no significant difference was found in univariate analysis. In addition, three cirrhosis-related parameters remained statistically different, including INR (OR 117.14, 95% CI: 4.19-3272.28, P = 0.005), albumin (OR 0.89, 95% CI: 0.80-0.99, P = 0.027), and platelet count (OR 0.992, 95% CI: 0.987-0.999, P = 0.002).

CONCLUSION: Besides the three cirrhosis-related parameters, DM was found to be the sole independent factor associated with HCC in patients with HBV-related cirrhosis, compared with those without cirrhosis.

Antifibrotic effect of hepatocyte growth factor-expressing mesenchymal stem cells in small-for-size liver transplant rats

Ischemia-reperfusion and chronic injuries associated with small-for-size liver transplantation (SFSLT) impair the regeneration of liver graft and induce liver fibrosis. Mesenchymal stem cells (MSCs) can prevent the development of liver fibrosis, and hepatocyte growth factor (HGF) can also attenuate liver cirrhosis. Our previous studies have demonstrated that higher occurrence of liver fibrosis existed in rats post-SFSLT, and that implantation of HGF/MSCs, the human HGF (hHGF)-expressing MSCs, can improve liver regeneration, reduce mortality of rats, as well as have the potent antifibrotic effect in this SFSLT model. In the present study, we implanted HGF/MSCs into liver grafts via the portal vein and investigated their role in antifibrosis effect, using a 30% SFSLT rat model. Fibrosis indexes, including laminin (LN), hyaluronic acid (HA) levels in serum and hydroxyproline (Hyp) content in the liver grafts, the expression of transforming growth factor-beta1 (TGF-beta(1)), rat HGF (rHGF), alpha-smooth muscle actin (alpha-SMA) in hepatic stellate cells (HSCs), alanine aminotransferase (ALT), total bilirubin (BIL), and albumin (ALB) levels in serum, in rats in different treatment groups were assessed at different time points. We found that HGF/MSCs significantly inhibited the formation of liver fibrosis in rats undergoing SFSLT, while MSCs and HGF had synergistic effects in the process. The antifibrosis effect of HGF/MSCs may have contributed in modulating the activation and apoptosis of HSCs, elevating the rHGF expression level, and decreasing the TGF-beta(1) secretion of activated HSCs. These studies suggest that HGF/MSCs may be a novel therapeutic option for the treatment of liver fibrosis after SFSLT.

Morphological and molecular pathology of CCL4-induced hepatic fibrosis in connexin43-deficient mice

Gap junction channels, formed by connexins (Cx), are involved in the maintenance of tissue homeostasis, cell growth, differentiation, and development. Several studies have shown that Cx43 is involved in the control of wound healing in dermal tissue. However, it remains unknown whether Cx43 plays a role in the control of liver fibrogenesis. Our study investigated the roles of Cx43 heterologous deletion on carbon tetrachloride (CCl(4))-induced hepatic fibrosis in mice. We administered CCl(4) to both Cx43-deficient (Cx43(+/-)) and wild-type mice and examined hepatocellular injury and collagen deposition by histological and ultrastructural analyses. Serum biochemical analysis was performed to quantify liver injury. Hepatocyte proliferation was analyzed immunohistochemically. Protein and messenger RNA (mRNA) expression of liver connexins were evaluated using immunohistochemistry as well as immunoblotting analysis and quantitative real-time PCR. We demonstrated that Cx43(+/-) mice developed excessive liver fibrosis compared with wild-type mice after CCl(4) -induced chronic hepatic injury, with thick and irregular collagen fibers. Histopathological evaluation showed that Cx43(+/-) mice present less necroinflammatory lesions in liver parenchyma and consequent reduction of serum aminotransferase activity. Hepatocyte cell proliferation was reduced in Cx43(+/-) mice. There was no difference in Cx32 and Cx26 protein or mRNA expression in fibrotic mice. Protein expression of Cx43 increased in CCl(4)-treated mice, although with aberrant protein location on cytoplasm of perisinusoidal cells. Our results demonstrate that Cx43 plays an important role in the control and regulation of hepatic fibrogenesis.

Resveratrol and liver disease: from bench to bedside and community

Liver diseases incorporate several maladies, which can range from benign histological changes to serious life-threatening conditions. These may include inborn metabolic disease, primary and metastatic cancers, alcoholic cirrhosis, viral hepatitis and drug-induced hepatotoxicity. Liver disease remains a major cause of morbidity and mortality with significant economic and social costs. Several novel approaches are currently being studied which may provide a better therapeutic outcome. The use of naturally occurring phytochemicals, some of them obtained from dietary sources, in the amelioration of illness have recently gained considerable popularity. These agents, having anti-oxidant and anti-inflammatory properties, provide a safe and effective means of ameliorating chronic disease. Resveratrol, a grape polyphenol, has shown considerable promise as a therapeutic agent in the treatment of the aforementioned liver ailments. Several studies have highlighted the hepatoprotective properties of resveratrol. Resveratrol has been shown to prevent hepatic damage because of free radicals and inflammatory cytokines, induce anti-oxidant enzymes and elevate glutathione content. Resveratrol has also been shown to modulate varied signal transduction pathways implicated in liver diseases. This review critically examines the current preclinical in vitro and in vivo studies on the preventive and therapeutic effects of resveratrol in liver diseases. The review highlights the pharmacological mechanisms involved in mediating the aforementioned effects. Toxicity, pharmacokinetics and clinical bioavailability of resveratrol are also reviewed in this article. The challenges involved, future directions and novel approaches such as site-specific drug delivery in the use of resveratrol for the prevention and treatment of liver disease are also discussed.

Course of disease and survival after onset of decompensation in hepatitis B virus-related cirrhosis

BACKGROUND

Data regarding the outcome of hepatitis B virus (HBV)-related cirrhosis after the onset of decompensation is scanty.

METHOD

From January 1998 to December 2008, a retrospective-prospective inception cohort study involving HBV-related decompensated cirrhotics was performed. Predictors of death and clinical events after the onset of decompensation were evaluated. Patients with co-infection with hepatitis C virus and/or human immunodeficiency virus, alcohol consumption to any degree and diabetes diagnosed before the detection of liver disease were excluded.

RESULT AND ANALYSIS

Two hundred and fifty-three patients (231 males, 139 e-negative), including 102 untreated patients, were analysed. The mean (+/-SD) age was 43.0 (+/-12.0) years. The mean (+/-SD) follow-up period was 47 (+/-47) months. Decompensation was the first presentation of liver disease in 210 (83%) patients. Ascites (70%) and variceal bleed (28%) were predominant modes of decompensation. Forty-three (17%) patients died (22 vs 14% in untreated and treated cohort, respectively; P=0.002). Type 2 hepato-renal syndrome was the commonest cause of death (32%). Survival was independent of e-antigen status. In the total cohorts, predictors of death were occurrence of sepsis with systemic inflammatory response (SIRS), ascites as the initial mode of decompensation, absence of antiviral therapy and events of high-grade hepatic encephalopathy [hazards ratios (HR) of 4.4, 3.6, 2.2 and 1.7 respectively]. In the untreated cohort, initial decompensation with ascites and development of sepsis with SIRS were independent predictors of death (HR 8.5 and 2.3 respectively), while 5-year survival was higher in patients having initial decompensation with variceal bleed vs ascites (29 vs 16%, respectively, P=0.002).

CONCLUSION

Decompensation with ascites and sepsis with SIRS predict reduced survival. Antiviral therapy beyond 6 months improves outcome.

Evolving challenges in hepatic fibrosis

Continued elucidation of the mechanisms of hepatic fibrosis has yielded a comprehensive and nuanced portrait of fibrosis progression and regression. The paradigm of hepatic stellate cell (HSC) activation remains the foundation for defining events in hepatic fibrosis and has been complemented by progress in a number of new areas. Cellular sources of extracellular matrix beyond HSCs have been identified. In addition, the role of chemokine, adipokine, neuroendocrine, angiogenic and NAPDH oxidase signaling in the pathogenesis of hepatic fibrosis has been uncovered, as has the contribution of extracellular matrix stiffness to fibrogenesis. There is also increased awareness of the contribution of innate immunity and greater understanding of the complexity of gene regulation in HSCs and myofibroblasts. Finally, both apoptosis and senescence have been recognized as orchestrated programs that eliminate fibrogenic cells during resolution of liver fibrosis. Ironically, the progress that has been made has highlighted the growing disparity between advances in the experimental setting and their translation into new diagnostic tools and treatments. As a result, focus is shifting towards overcoming key translational challenges in order to accelerate the development of new therapies for patients with chronic liver disease.

Accuracy of ultrasound to identify chronic liver disease

AIM: To identify and assess studies reporting the diagnostic performance of ultrasound imaging for identifying chronic liver disease (CLD) in a high risk population.

METHODS: A search was performed to identify studies investigating the diagnostic accuracy of ultrasound imaging for CLD. Two authors independently used the quality assessment of diagnostic accuracy studies (QUADAS) checklist to assess the methodological quality of the selected studies. Inter-observer reliability of the QUADAS tool was assessed by measuring the degree of agreement (percent agreement, κ statistic) between the reviewers for each assessment prior to a consensus meeting. The characteristics of each study population, sensitivity and specificity results for the index tests, and results of any testing for observer agreement were extracted from the reports. Receiver Operator Characteristic plots were generated using Microsoft Excel 2003 software and used to graphically display the diagnostic performance data and to explore the relationships between the reported ultrasound techniques and study characteristics, and methodology quality.

RESULTS: Twenty-one studies published between 1991 and 2009 were retained for data extraction, analysis and assessment for methodological quality. Assessment of methodology quality was performed on the 21 selected studies by two independent reviewers (RA & KT) using the QUADAS assessment tool. Across all studies the mean number of responses within the QUADAS assessment tool was 10 (range 7-13) for “Yes”, 1 (range 0-3) for “No” and 3 (range 0-6) for “unclear”. Inter-rater agreement for assessment of methodology quality was significantly greater than chance when assessing for representative spectrum, clear selection criteria, appropriate delay between reference and index tests, adequate descriptions of the index and reference tests, reference and index test blinding, and if relevant clinical information was provided. Seven studies reported moderate to high observer agreement for ultrasound techniques. Studies which clearly reported blinding performed better than the other studies for diagnostic accuracy, and lower diagnostic accuracy was evident for populations with lower prevalence of disease. Assessment of the liver surface using ultrasound consistently had moderate diagnostic accuracy across studies which demonstrated good research methodology. Other techniques demonstrated variable or poor to fair diagnostic accuracy.

CONCLUSION: Ultrasound of the liver surface is a useful diagnostic tool in patients at risk of CLD when assessing whether they should undergo a liver biopsy.

Embryonic and induced pluripotent stem cells as a model for liver disease

Induced pluripotent stem (iPS) cells are human somatic cells that have been reprogrammed to a pluripotent state. Through several elegant technologies, we are now able to generate human iPS cells with disease genotypes that could serve as invaluable tools for human disease modeling. This could lead to an understanding of the root causes of a disease and to the development of effective prophylactic and therapeutic strategies for it. However, we are still far from generating fully functional liver cells from stem cells, including iPS cells, on in vitro culture systems. Tissue-engineering techniques have opened the window to inducing a functional fate for differentiated cells by providing a microenvironment that allows the maintenance of signals similar to those found in the natural microenvironment. Here we review the current technology to establish iPS cells and discuss strategies to generate human liver disease modeling using iPS cell technology in concert with bioengineering approaches.

The challenge of developing novel pharmacological therapies for non-alcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) is an umbrella term for a series of hepatic pathologies that begin with relatively benign steatosis and can, with appropriate triggers, lead to the serious entity of non-alcoholic steatohepatitis (NASH). This sets the stage for liver fibrosis and finally the development of cirrhosis in up to 20% of patients with NASH. NAFLD, already among the most common diseases in industrialized countries, is increasing in prevalence and roughly affects 30% of US adults and 10% of US children alone. NAFLD is strongly associated with insulin resistance (IR) and represents the hepatic manifestation of the metabolic syndrome. Indeed, treatments aimed at reducing IR are the current mainstay of therapeutic approaches to NAFLD. While lifestyle interventions may produce limited degrees of success, there remains an urgent need for improved pharmacological therapies. Emerging diagnostic and therapeutic opportunities as well as future developments in NAFLD, NASH and liver fibrosis were discussed by a panel of experts and are presented herein. Promising novel therapeutic targets include inhibitors of dipeptidyl peptidase 4 and the renin-angiotensin system. However, improved non-invasive technologies to diagnose and stage NAFLD are needed. Combined with a better understanding of the pathophysiological processes that underlie the mechanisms of hepatic fibrogenesis in NASH, rapid clinical validation of novel therapies is expected.

Increased plasma malondialdehyde in patients with viral cirrhosis and its relationships to plasma nitric oxide, endotoxin, and portal pressure

BACKGROUND AND AIM

Increased oxidative stress is involved in the development of portal hypertension in cirrhosis. Our study aimed to assess the relationship between oxidative stress and hemodynamic parameters in cirrhotic patients.

METHODS

Forty-two patients with viral cirrhosis and 24 normal controls were enrolled. Measurements of plasma levels of malondialdehyde (MDA), nitrite/nitrate (NOx), endotoxin, and activities of superoxide dismutase (SOD) were carried out in all subjects. Systemic and splanchnic hemodynamic measurements were carried out in cirrhotic patients.

RESULTS

Plasma levels of MDA, endotoxin, and NOx were significantly higher in cirrhotic patients than in normal controls (900 +/- 751 versus 226 +/- 16 nM, P < 0.01; 62.0 +/- 26.0 versus 14.8 +/- 4.1 pg/mL, P < 0.01; 50.5 +/- 22.6 versus 15.0 +/- 9.2 nM, P < 0.01, respectively). Activities of SOD were significantly decreased in cirrhotic patients compared with in normal controls (2.62 +/- 0.7 versus 6.8 +/- 0.4 U/mL). Further, plasma levels of MDA in cirrhotic patients were significantly positively associated with hepatic venous pressure gradient (HVPG) (r = 0.35; P = 0.025), wedge hepatic venous pressure (WHVP) (r = 0.42; P = 0.007), and hepatic sinusoid resistance (HSR) (r = 0.33; P = 0.033). Plasma MDA levels also correlated positively with plasma endotoxin (r = 0.71, P < 0.001) and NOx (r = 0.55, P < 0.001) levels in the cirrhotic patients. Multiregression analysis showed that the independent and strongest factors to predict HVPG, WHVP, and HSR are plasma levels of NOx, MDA, and endotoxin, respectively.

CONCLUSION

This study suggests a close interaction among MDA, endotoxin, and NOx and that these substances are also associated with hemodynamic derangement in cirrhosis.

Broad-spectrum matrix metalloproteinase inhibition curbs inflammation and liver injury but aggravates experimental liver fibrosis in mice

Background

Liver fibrosis is characterized by excessive synthesis of extracellular matrix proteins, which prevails over their enzymatic degradation, primarily by matrix metalloproteinases (MMPs). The effect of pharmacological MMP inhibition on fibrogenesis, however, is largely unexplored. Inflammation is considered a prerequisite and important co-contributor to fibrosis and is, in part, mediated by tumor necrosis factor (TNF)-α-converting enzyme (TACE). We hypothesized that treatment with a broad-spectrum MMP and TACE-inhibitor (Marimastat) would ameliorate injury and inflammation, leading to decreased fibrogenesis during repeated hepatotoxin-induced liver injury.

Methodology/Principal Findings

Liver fibrosis was induced in mice by repeated carbon tetrachloride (CCl4) administration, during which the mice received either Marimastat or vehicle twice daily. A single dose of CCl₄ was administered to investigate acute liver injury in mice pretreated with Marimastat, mice deficient in Mmp9, or mice deficient in both TNF-α receptors. Liver injury was quantified by alanine aminotransferase (ALT) levels and confirmed by histology. Hepatic collagen was determined as hydroxyproline, and expression of fibrogenesis and fibrolysis-related transcripts was determined by quantitative reverse-transcription polymerase chain reaction. Marimastat-treated animals demonstrated significantly attenuated liver injury and inflammation but a 25% increase in collagen deposition. Transcripts related to fibrogenesis were significantly less upregulated compared to vehicle-treated animals, while MMP expression and activity analysis revealed efficient pharmacologic MMP-inhibition and decreased fibrolysis following Marimastat treatment. Marimastat pre-treatment significantly attenuated liver injury following acute CCl₄-administration, whereas Mmp9 deficient animals demonstrated no protection. Mice deficient in both TNF-α receptors exhibited an 80% reduction of serum ALT, confirming the hepatoprotective effects of Marimastat via the TNF-signaling pathway.

Conclusions/Significance

Inhibition of MMP and TACE activity with Marimastat during chronic CCl₄ administration counterbalanced any beneficial anti-inflammatory effect, resulting in a positive balance of collagen deposition. Since effective inhibition of MMPs accelerates fibrosis progression, MMP inhibitors should be used with caution in patients with chronic liver diseases.

Neuropilin-1 promotes cirrhosis of the rodent and human liver by enhancing PDGF/TGF-beta signaling in hepatic stellate cells

PDGF-dependent hepatic stellate cell (HSC) recruitment is an essential step in liver fibrosis and the sinusoidal vascular changes that accompany this process. However, the mechanisms that regulate PDGF signaling remain incompletely defined. Here, we found that in two rat models of liver fibrosis, the axonal guidance molecule neuropilin-1 (NRP-1) was upregulated in activated HSCs, which exhibit the highly motile myofibroblast phenotype. Additionally, NRP-1 colocalized with PDGF-receptor beta (PDGFRbeta) in HSCs both in the injury models and in human and rat HSC cell lines. In human HSCs, siRNA-mediated knockdown of NRP-1 attenuated PDGF-induced chemotaxis, while NRP-1 overexpression increased cell motility and TGF-beta-dependent collagen production. Similarly, mouse HSCs genetically modified to lack NRP-1 displayed reduced motility in response to PDGF treatment. Immunoprecipitation and biochemical binding studies revealed that NRP-1 increased PDGF binding affinity for PDGFRbeta-expressing cells and promoted downstream signaling. An NRP-1 neutralizing Ab ameliorated recruitment of HSCs, blocked liver fibrosis in a rat model of liver injury, and also attenuated VEGF responses in cultured liver endothelial cells. In addition, NRP-1 overexpression was observed in human specimens of liver cirrhosis caused by both hepatitis C and steatohepatitis. These studies reveal a role for NRP-1 as a modulator of multiple growth factor targets that regulate liver fibrosis and the vascular changes that accompany it and may have broad implications for liver cirrhosis and myofibroblast biology in a variety of other organ systems and disease conditions.

Paediatric chronic liver diseases: how to investigate and follow up? Role of imaging in the diagnosis of fibrosis

Chronic liver diseases are rare in children, but encompass a wide spectrum of disorders that may all be complicated by liver fibrosis and therefore by portal hypertension. They may be classified according to the level of portal flow obstruction: prehepatic, intrahepatic or suprahepatic. Most of them, except presinusoidal diseases, may progress to cirrhosis that carries additional risks of impaired liver function and development of hepatocellular carcinoma. Imaging plays an important role in guiding the diagnosis and biopsy and for follow-up during treatment. US, with high-frequency transducers and Doppler, is the first modality of choice, directs the rest of the investigations and guides interventional radiology. MDCT has made great progress and has replaced angiography for diagnostic purposes. MRI is indicated for parenchyma and nodule characterization and for biliary tract evaluation. To avoid liver biopsy, several elasticity imaging techniques have been developed and have to be evaluated for accuracy and convenience in children. The role of each modality with main imaging findings is described in extrahepatic portal vein obstruction, hepatoportal sclerosis, congenital hepatic fibrosis, cirrhosis and Budd-Chiari syndrome.

Intrahepatic peripheral cholangiocarcinoma in cirrhosis patients may display a vascular pattern similar to hepatocellular carcinoma on contrast-enhanced ultrasound

The aim of this study was to describe the imaging features by contrast-enhanced ultrasound (CEUS) of intrahepatic cholangiocarcinoma (ICC) in cirrhosis patients. We registered the CEUS images of cirrhosis patients with histologically confirmed ICC. In all cases magnetic resonance imaging (MRI) was done to confirm the diagnosis and/or staging purposes. A total of 21 patients met all the criteria to be included in the study. The median nodule size was 32 mm. All nodules showed contrast enhancement at arterial phase; in 10 cases it was homogeneous and in 11 cases peripheral (rim-like). All nodules displayed washout during the venous phases; it appeared during the first 60 seconds in 10 nodules, between 60-120 seconds in five cases, and in six cases after 2 minutes. Ten nodules (five larger than 2 cm) displayed homogeneous contrast uptake followed by washout and they correspond to the specific pattern of hepatocellular carcinoma according to the American Association for the Study of Liver Diseases criteria. However, none of these lesions displayed washout on MRI.

CONCLUSION

CEUS should not be used as the sole imaging technique for conclusive hepatocellular carcinoma diagnosis and if the MRI does not display the diagnostic vascular pattern, a confirmatory biopsy is mandatory.

Liver stiffness: a novel parameter for the diagnosis of liver disease

The noninvasive quantitation of liver stiffness (LS) by ultrasound based transient elastography using FibroScan® has revolutionized the diagnosis of liver diseases, namely liver cirrhosis. Alternative techniques such as acoustic radiation impulse frequency imaging or magnetic resonance elastography are currently under investigation. LS is an excellent surrogate marker of advanced fibrosis (F3) and cirrhosis (F4) outscoring all previous noninvasive approaches to detect cirrhosis. LS values below 6 kPa are considered as normal and exclude ongoing liver disease. LS of 8 and 12.5 kPa represent generally accepted cut-off values for F3 and F4 fibrosis. LS highly correlates with portal pressure, and esophageal varices are likely at values >20 kPa. Many other factors may also increase LS such as hepatic infiltration with tumor cells, mast cells (mastocytosis), inflammatory cells (all forms of hepatitis) or amyloidosis. In addition, LS is directly correlated with the venous pressure (eg, during liver congestion) and is increased during mechanic cholestasis. Thus, LS should always be interpreted in the context of clinical, imaging and laboratory findings. Finally, LS has helped to better understand the molecular mechanisms underlying liver fibrosis. The novel pressure-stiffness-fibrosis sequence hypothesis is introduced.

What is the best alternative to inulin clearance to estimate GFR in patients with decompensated alcoholic cirrhosis?

BACKGROUND

Accurate evaluation of the glomerular filtration rate (GFR) in patients awaiting liver transplantation is important because they have a greater risk of impaired renal function. A major percentage of these patients have alcoholic cirrhosis, and the accuracy of bedside used GFR estimates have not been specifically evaluated in this group. The aim of this study was to evaluate the validity of the simplified Modification of Diet in Renal Diseases (MDRD) and Cockcroft and Gault (CG) formulas in patients with decompensated alcoholic cirrhosis in comparison to inulin clearance as the reference method.

METHODS

GFR estimated by the simplified MDRD and CG formulas were retrospectively compared to the true GFR measured by inulin clearance in a single-centre cohort of 148 patients with decompensated alcoholic cirrhosis.

RESULTS

Mean ± standard deviation of age, body mass index, inulin clearance and MDRD and CG estimates were 54.4 ± 6.9 years, 26.5 ± 4.7 kg/m(2), 76.9 ± 28.0 mL/min per 1.73 m(2), 99.4 ± 34.0 mL/min per 1.73 m(2) and 98.7 ± 32.0 mL/min per 1.73 m(2), respectively; 70% of the patients had a GFR, measured by inulin clearance, below 90 mL/min per 1.73 m(2). The difference between estimated GFR and true GFR were 23 ± 23 mL/min per 1.73 m(2) for MDRD and 22 ± 20 mL/min per 1.73 m(2) for Cockcroft and Gault.

CONCLUSIONS

The simplified MDRD and CG formulas largely overestimated GFR in patients with decompensated alcoholic cirrhosis. Results of such bedside formulas should be interpreted with caution in these patients.

Capsule endoscopy in portal hypertension

Since the introduction of small bowel capsule endoscopy, and more recently of esophageal capsule endoscopy, these diagnostic tools have become available for the evaluation of the consequences of portal hypertension in the esophagus, stomach, and small intestine. The main advantage of the esophageal and the small bowel capsule is the relatively less invasiveness that could potentially increase patients' adherence to endoscopic screening/surveillance programs. When esophageal capsule endoscopy was compared with traditional gastroscopy, it showed good sensitivity and specificity in recognizing the presence and the size of esophageal varices. However, the results are not consistent among studies, and more data are needed.

Circulating markers of liver fibrosis progression

INTRODUCTION

Fibrogenesis is a typical reaction of the liver to injury. In the case of overstimulation of fibrogenesis clinically significant fibrosis and, eventually, cirrhosis occur. Treatment of liver cirrhosis is limited, therefore it is important to screen and monitor patients at risk of cirrhosis. Noninvasive parameters are ideal for this purpose due to their risk profile and repeatability.

METHODS

Systematic review of literature.

RESULTS

Among large number of proposed biomarkers, there is a distinct difference between two groups or classes. Class I biomarkers are associated with the process of fibrogenesis, their presence in the serum is the result of the increased turnover of extracellular matrix. Class II biomarkers and their combinations are mostly markers of liver function or structural damage. We have identified 27 Class I and 13 Class II biomarkers that have been proposed in the literature. We have evaluated in detail those which reached limited clinical application.

CONCLUSION

General clinical acceptance of these biomarkers is low because of various drawbacks. Simple and readily available biomarkers have low accuracy in predicting liver fibrosis and more advanced markers have low cost-benefit ratio. Therefore liver biopsy remains the "gold standard" for diagnosis of fibrosis. However potential noninvasive alternatives exist and their implementation could be valuable.

Administration of a low dose of sildenafil for 1 week decreases intrahepatic resistance in rats with biliary cirrhosis: the role of NO bioavailability

Increasing NO bioavailability improves hepatic endothelial dysfunction, which ameliorates intrahepatic resistance and portal hypertension. Acute administration of sildenafil increases hepatic production of NO with a reduction in hepatic sinusoid resistance in cirrhotic patients and enhances the vasorelaxation response to NO in cirrhotic rat livers. However, the mechanisms were still unclear. Therefore, our present study aims to evaluate the effects and mechanisms of administration of sildenafil for 1 week on the hepatic microcirculation of cirrhotic rats. Cirrhosis was induced by bile duct ligation with sham-operated rats serving as normal controls. Intrahepatic resistance was evaluated by in situ liver perfusion. Expression of phospho-eNOS (endothelial NO synthase), iNOS (inducible NO synthase), phospho-Akt, PDE-5 (phosphodiesterase-5) and sGC (soluble guanylate cyclase) were determined by Western blot analysis. Biosynthesis of BH4 (tetrahydrobiopterin) and GTPCH-I (GTP cyclohydrolase I) activity were examined by HPLC. Intravital microscopy was used to observe the direct change in hepatic microcirculation. In cirrhotic rat livers, sildenafil treatment increased hepatic sinusoid volumetric flow, NO bioavailability, BH4, GTPCH-I activity, and the protein expression of phospho-Akt, phospho-eNOS and sGC. These events were associated with reduced protein expression of PDE-5, portal perfusion pressure and portal vein pressure. In contrast, sham rats did not produce any significant change in these measurements. In conclusion, sildenafil treatment improves endothelial dysfunction by augmenting NO bioavailability in the hepatic microcirculation.

Serotonin promotes tumor growth in human hepatocellular cancer

In addition to its function as a neurotransmitter and vascular active molecule, serotonin is also a mitogen for hepatocytes and promotes liver regeneration. A possible role in hepatocellular cancer has not yet been investigated. Human hepatocellular cancer cell lines Huh7 and HepG2 were used to assess the function of serotonin in these cell lines. Characteristics of autophagy were detected with transmission electron microscopy, immunoblots of microtubule-associated protein light chain 3(LC3) and p62 (sequestosome 1). Immunoblots of the mammalian target of rapamycin (mTOR) and its downstream targets p70S6K and 4E-BP1 were used to investigate signaling pathways of serotonin. Two different animal models served as principle of proof of in vitro findings. Clinical relevance of the experimental findings was evaluated with a tissue microarray from 168 patients with hepatocellular carcinoma. Serotonin promotes tumor growth and survival in starved hepatocellular carcinoma cells. During starvation hepatocellular carcinoma cells exhibited characteristics of autophagy, which disappeared in serotonin-treated cells. Rapamycin, an inhibitor of mTOR, is known to induce autophagy. Serotonin could override rapamycin by an mTOR-independent pathway and activate common downstream signals such as p70S6K and 4E-BP1. In two tumor models of the mouse, inhibition of serotonin signaling consistently impaired tumor growth. Human biopsies revealed expression of the serotonin receptor HTR2B, correlating with downstream signals, e.g., phosphorylated p70S6K and proliferation.

CONCLUSION

This study provides evidence that serotonin is involved in tumor growth of hepatocellular cancer by activating downstream targets of mTOR, and therefore serotonin-related pathways might represent a new treatment strategy.

Skeletal muscle-derived stem cells differentiate into hepatocyte-like cells and aid in liver regeneration

The liver is unique for its ability to regenerate after injury, however, critical injuries or disease cause it to lose this quality. Stem cells have been explored as a possibility to restore the function of seriously damaged livers, based on their self-renewability and multiple differentiation capacity. These experiments examine the ability of muscle derived stem cells (MDSCs) to differentiate into hepatocyte-like cells in vitro and acquire functional liver attributes for repairing damaged livers. In vitro experiments were performed using MDSCs from postnatal mice and mouse hepatocyte cell lines. Our data revealed that MDSCs differentiated into hepatocyte-like cells and expressed liver cell markers, albumin, hepatocyte nuclear factor 4 α, and alpha feto-protein, both at the RNA and protein level. Additionally, in vivo studies showed successful engraftment of MDSCs into hepatectomized mouse livers of mice. These results provide evidence suggesting that MDSCs have the capacity to differentiate into liver cell-like cells and may serve as potential candidates to aid in liver regeneration.

Risk factor analysis in patients with liver cirrhosis undergoing cardiovascular operations

BACKGROUND

Variable outcomes of cardiac operations have been reported in cirrhotic patients, but no definitive predictive prognostic factors have been established. This retrospective study assessed operative results to identify risk factors associated with morbidity after cardiovascular operations in cirrhotic patients.

METHODS

The study comprised 42 cirrhotic patients who underwent cardiovascular operations from January 1991 to January 2009. Thirty patients were Child-Turcotte-Pugh class A, and 12 were class B. Hospital morbidity occurred in 13 patients (31.0%; M group), including 4 who died in-hospital. Patients without severe complications (N group) were compared with the M group patients. The Model for End-Stage Liver Disease (MELD) score was evaluated in 25 patients.

RESULTS

Significant differences in hospital morbidity between the M vs N groups were identified for platelet count (8.7 +/- 3.8 vs 12.1 +/- 4.2 x 10(4)/microL), MELD score (17.8 +/- 5.3 vs 9.8 +/- 4.9), operation time (370 +/- 88 vs 313 +/- 94 minutes), and cardiopulmonary bypass time (174 +/- 46 vs 149 +/- 53 minutes) in univariate analyses (p < 0.005). Platelet count, operation time, and age were significantly associated with hospital morbidity in multivariate analyses (p < 0.005). Platelet count of 9.6 x 10(4)/microL and MELD score of 13 were cutoff values for hospital morbidity.

CONCLUSIONS

Careful consideration of operative indications and methods are necessary in cirrhotic patients with low platelet counts or high MELD scores. A high incidence of hospital morbidity is predicted in patients with platelet counts of less than 9.6 x 10(4)/microL or MELD scores exceeding 13.

Mesenchymal stem cells as therapeutic tools and gene carriers in liver fibrosis and hepatocellular carcinoma

Mesenchymal stem (stromal) cells (MSCs) are a source of circulating progenitors that are able to generate cells of all mesenchymal lineages and to cover cellular demands of injured tissues. The extent of their transdifferentiation plasticity remains controversial. Cells with MSC properties have been obtained from diverse tissues after purification and expansion in vitro. These cellular populations are heterogeneous and under certain conditions show pluripotent-like properties. MSCs present immunosuppressive and anti-inflammatory features and high migratory capacity toward inflamed or remodeling tissues. In this study we review available data regarding factors and signaling axes involved in the chemoattraction and engraftment of MSCs to an injured tissue or to a tissue undergoing active remodeling. Moreover, experimental evidence in support of uses of MSCs as vehicles of therapeutic genes is discussed. Because of its regenerative capacity and its particular immune properties, the liver is a good model to analyze the potential of MSC-based therapies. Finally, the potential application of MSCs and genetically modified MSCs in liver fibrosis and hepatocellular carcinoma (HCC) is proposed in view of available evidence.

Macrophage-mediated phagocytosis of apoptotic cholangiocytes contributes to reversal of experimental biliary fibrosis

Studies have suggested the reversibility of liver fibrosis, but the mechanisms of fibrosis reversal are poorly understood. We investigated the possible functional link between apoptosis, macrophages, and matrix turnover in rat liver during reversal of fibrosis secondary to bile duct ligation (BDL). Biliary fibrosis was induced by BDL for 4 wk. After Roux-en-Y (RY)-bilio-jejunal-anastomosis, resolution of fibrosis was monitored for up to 12 wk by hepatic collagen content, matrix metalloproteinase (MMP) expression and activities, and fibrosis-related gene expression. MMP expression and activities were studied in macrophages after engulfment of apoptotic cholangiocytes in vitro. Hepatic collagen decreased to near normal at 12 wk after RY-anastomosis. During reversal, profibrogenic mRNA declined, whereas expression of several profibrolytic MMPs increased. Fibrotic septa showed fragmentation at week 4 and disappeared at week 12. Peak histological remodeling at week 4 was characterized by massive apoptosis of cytokeratin 19+ cholangiocytes, >90% in colocalization with CD68+ macrophages, and a 2- to 7.5-fold increase in matrix-degrading activities. In vitro, phagocytosis of apoptotic cholangiocytes induced matrix-degrading activities and MMP-3, -8, and -9 in rat peritoneal macrophages. We concluded that reconstruction of bile flow after BDL leads to an orchestrated fibrolytic program that results in near complete reversal of advanced fibrosis. The peak of connective tissue remodeling and fibrolytic activity is associated with massive apoptosis of cholangiocytes and their phagocytic clearance by macrophages in vivo. Macrophages upregulate MMPs and become fibrolytic effector cells upon apoptotic cholangiocyte engulfment in vitro, suggesting that phagocytosis-associated MMP induction in macrophages significantly contributes to biliary fibrosis reversal.

Hepatotrophic factors reduce hepatic fibrosis in rats

CONTEXT: Hepatic fibrosis occurs in response to several aggressive agents and is a predisposing factor in cirrhosis. Hepatotrophic factors were shown to stimulate liver growth and to restore the histological architecture of the liver. They also cause an improvement in liver function and accelerate the reversion of fibrosis before it progresses to cirrhosis. OBJECTIVE: To test the effects of hepatic fibrosis solution composed by amino acids, vitamins, glucose, insulin, glucagon and triiodothyronine on hepatic fibrosis in rats. METHODS: Fibrosis was induced in rats by gastric administration of dimethylnitrosamine (10 mg/kg) for 5 weeks. After liver biopsy, the rats received either hepatotrophic factors solution (40 mg/kg/day) or saline solution for 10 days by intraperitoneal injection. Blood samples and liver fragments were collected for hepatic function analysis, standard histopathology evaluation, and morphometric collagen quantification. RESULTS: Rats in the hepatotrophic factors group showed a decrease of the histopathological components of fibrosis and an increase of their hepatic mass (12.2%). There was no development of neoplasic lesions in both groups. Compared with the saline group, the hepatotrophic factors group also had a decrease of blood levels of hepatic-lesion markers (AST, ALT) and a decrease of collagen content in the portal spaces (31.6%) and perisinusoidal spaces (42.3%), as well as around the hepatic terminal vein (57.7%). Thus, hepatotrophic factors administration in the portal blood promoted a regenerative hepatic response, with an overall reduction of the volumetric density of collagen, improved hepatic function, and a general improvement in the histopathological aspects of fibrosis. CONCLUSION: Taken together, these results suggest the potential therapeutic use of this hepatotrophic factors solution to treat chronic liver diseases.

The histogenesis of regenerative nodules in human liver cirrhosis

Here, we investigate the clonality and cells of origin of regenerative nodules in human liver cirrhosis using mitochondrial DNA (mtDNA) mutations as markers of clonal expansion. Mutated cells are identified phenotypically by deficiency in the entirely mtDNA encoded cytochrome c oxidase (CCO) enzyme by histochemical and immunohistochemical methods. Nodules were classified as either CCO-deficient or CCO-positive, and among 526 nodules from 10 cases, 18% were homogeneously CCO-deficient, whereas only 3% had a mixed phenotype. From frozen sections, hepatocytes were laser-capture microdissected from several sites within individual CCO-deficient nodules. Mutations were identified by polymerase chain reaction sequencing of the entire mtDNA genome. In all cases except for one, the nodules were monoclonal in nature, possessing up to four common mutations in all hepatocytes in a given nodule. Moreover, the identification of identical mutations in hepatic progenitor cells abutting CCO-deficient nodules proves that nodules can have their origins from such cells.

CONCLUSION

These data support a novel pathway for the monoclonal derivation of human cirrhotic regenerative nodules from hepatic progenitor cells.

MR imaging of liver fibrosis: current state of the art

Chronic liver disease is a major public health problem worldwide. Liver fibrosis, a common feature of almost all causes of chronic liver disease, involves the accumulation of collagen, proteoglycans, and other macromolecules within the extracellular matrix. Fibrosis tends to progress, leading to hepatic dysfunction, portal hypertension, and ultimately cirrhosis. Liver biopsy, the standard of reference for diagnosing liver fibrosis, is invasive, costly, and subject to complications and sampling variability. These limitations make it unsuitable for diagnosis and longitudinal monitoring in the general population. Thus, development of a noninvasive, accurate, and reproducible test for diagnosis and monitoring of liver fibrosis would be of great value. Conventional cross-sectional imaging techniques have limited capability to demonstrate liver fibrosis. In clinical practice, imaging studies are usually reserved for evaluation of the presence of portal hypertension or hepatocellular carcinoma in cases that have progressed to cirrhosis. In response to the rising prevalence of chronic liver diseases in Western nations, a number of imaging-based methods including ultrasonography-based transient elastography, computed tomography-based texture analysis, and diverse magnetic resonance (MR) imaging-based techniques have been proposed for noninvasive diagnosis and grading of hepatic fibrosis across its entire spectrum of severity. State-of-the-art MR imaging-based techniques in current practice and in development for noninvasive assessment of liver fibrosis include conventional contrast material-enhanced MR imaging, double contrast-enhanced MR imaging, MR elastography, diffusion-weighted imaging, and MR perfusion imaging.

MR imaging of liver fibrosis: current state of the art

Chronic liver disease is a major public health problem worldwide. Liver fibrosis, a common feature of almost all causes of chronic liver disease, involves the accumulation of collagen, proteoglycans, and other macromolecules within the extracellular matrix. Fibrosis tends to progress, leading to hepatic dysfunction, portal hypertension, and ultimately cirrhosis. Liver biopsy, the standard of reference for diagnosing liver fibrosis, is invasive, costly, and subject to complications and sampling variability. These limitations make it unsuitable for diagnosis and longitudinal monitoring in the general population. Thus, development of a noninvasive, accurate, and reproducible test for diagnosis and monitoring of liver fibrosis would be of great value. Conventional cross-sectional imaging techniques have limited capability to demonstrate liver fibrosis. In clinical practice, imaging studies are usually reserved for evaluation of the presence of portal hypertension or hepatocellular carcinoma in cases that have progressed to cirrhosis. In response to the rising prevalence of chronic liver diseases in Western nations, a number of imaging-based methods including ultrasonography-based transient elastography, computed tomography-based texture analysis, and diverse magnetic resonance (MR) imaging-based techniques have been proposed for noninvasive diagnosis and grading of hepatic fibrosis across its entire spectrum of severity. State-of-the-art MR imaging-based techniques in current practice and in development for noninvasive assessment of liver fibrosis include conventional contrast material-enhanced MR imaging, double contrast-enhanced MR imaging, MR elastography, diffusion-weighted imaging, and MR perfusion imaging.

Alpha-lipoic acid inhibits hepatic PAI-1 expression and fibrosis by inhibiting the TGF-beta signaling pathway

Accumulating evidence suggests that plasminogen activator inhibitor (PAI)-1 plays an important role in the development of hepatic fibrosis via its involvement in extracellular matrix remodeling. We previously reported that alpha-lipoic acid (ALA), a naturally occurring thiol antioxidant, prevents hepatic steatosis by inhibiting the expression of sterol regulatory element binding protein-1c. The aim of the present study was to determine whether ALA prevents hepatic PAI-1 expression and fibrosis through the inhibition of multiple TGF-beta-mediated molecular mediators. We investigated whether ALA inhibited the development of hepatic fibrosis in mice following bile duct ligation (BDL), an established animal model of liver fibrosis. We found that ALA markedly inhibited BDL-induced hepatic fibrosis and PAI-1 expression. We also found that ALA attenuated TGF-beta-stimulated PAI-1 mRNA expression, and inhibited PAI-1 promoter activity in liver cells; this effect was mediated by Smads and the JNK and ERK pathways. The results of the present study indicate that ALA inhibits hepatic PAI-1 expression through inhibition of TGF-beta-mediated molecular mediators, including Smad3, AP1, and Sp1, and prevents the development of BDL-induced hepatic fibrosis. These findings suggest that ALA may have a clinical application in preventing the development and progression of hepatic fibrosis.

Laparoscopic splenectomy may be a superior supportive intervention for cirrhotic patients with hypersplenism

BACKGROUND AND AIMS

To evaluate and compare laparoscopic splenectomy and partial splenic embolization as supportive intervention for cirrhotic patients with hypersplenism to overcome peripheral cytopenia before the initiation of and during interferon therapy or anticancer therapy for hepatocellular carcinoma.

METHODS

Between December 2000 and April 2008, 43 Japanese cirrhotic patients with hypersplenism underwent either laparoscopic splenectomy or partial splenic embolization as a supportive intervention to facilitate the initiation and completion of either interferon therapy or anticancer therapy for hepatocellular carcinoma. We reviewed the peri- and post-intervention outcomes and details of the subsequent planned main therapies. For interferon therapy, the rate of completion, the rate of treatment cessation and virological responses were evaluated. Anti-cancer therapies for hepatocellular carcinoma included liver resection, ablation therapy, intra-arterial chemotherapy, and transarterial chemoembolization.

RESULTS

All patients tolerated the operations well with no significant complications. The platelet count was significantly higher in the laparoscopic splenectomy group than in the partial splenic embolization group at 1 and 2 weeks after the intervention. Interferon therapy was stopped in two patients in the partial splenic embolization group due to recurrent thrombocytopenia whereas all patients in the laparoscopic splenectomy group completed interferon therapy. The planned anticancer therapies were performed in all patients, and were completed in all patients without any problems or major complications.

CONCLUSION

Laparoscopic splenectomy may be superior to partial splenic embolization as a supportive intervention for cirrhotic patients with hypersplenism. Future prospective, randomized controlled patient studies are required to confirm these findings.

Role of the receptor for advanced glycation end products in hepatic fibrosis

AIM: To study the role of advanced glycation end products (AGE) and their specific receptor (RAGE) in the pathogenesis of liver fibrogenesis.

METHODS: In vitro RAGE expression and extracellular matrix-related gene expression in both rat and human hepatic stellate cells (HSC) were measured after stimulation with the two RAGE ligands, advanced glycation end product-bovine serum albumin (AGE-BSA) and N^ε-(carboxymethyl) lysine (CML)-BSA, or with tumor necrosis factor-α (TNF-α). In vivo RAGE expression was examined in models of hepatic fibrosis induced by bile duct ligation or thioacetamide. The effects of AGE-BSA and CML-BSA on HSC proliferation, signal transduction and profibrogenic gene expression were studied in vitro.

RESULTS: In hepatic fibrosis, RAGE expression was enhanced in activated HSC, and also in endothelial cells, inflammatory cells and activated bile duct epithelia. HSC expressed RAGE which was upregulated after stimulation with AGE-BSA, CML-BSA, and TNF-α. RAGE stimulation with AGE-BSA and CML-BSA did not alter HSC proliferation, apoptosis, fibrogenic signal transduction and fibrosis- or fibrolysis-related gene expression, except for marginal upregulation of procollagen α1(I) mRNA by AGE-BSA.

CONCLUSION: Despite upregulation of RAGE in activated HSC, RAGE stimulation by AGE does not alter their fibrogenic activation. Therefore, RAGE does not contribute directly to hepatic fibrogenesis.