Liver cirrhosis

Cannabidiol causes activated hepatic stellate cell death through a mechanism of endoplasmic reticulum stress-induced apoptosis

The major cellular event in the development and progression of liver fibrosis is the activation of hepatic stellate cells (HSCs). Activated HSCs proliferate and produce excess collagen, leading to accumulation of scar matrix and fibrotic liver. As such, the induction of activated HSC death has been proposed as a means to achieve resolution of liver fibrosis. Here we demonstrate that cannabidiol (CBD), a major non-psychoactive component of the plant Cannabis sativa, induces apoptosis in activated HSCs through a cannabinoid receptor-independent mechanism. CBD elicits an endoplasmic reticulum (ER) stress response, characterized by changes in ER morphology and the initiation of RNA-dependent protein kinase-like ER kinase-, activating transcription factor-6-, and inositol-requiring ER-to-nucleus signal kinase-1 (IRE1)-mediated signaling cascades. Furthermore, CBD induces downstream activation of the pro-apoptotic IRE1/ASK1/c-Jun N-terminal kinase pathway, leading to HSC death. Importantly, we show that this mechanism of CBD-induced ER stress-mediated apoptosis is specific to activated HSCs, as it occurs in activated human and rat HSC lines, and in primary in vivo-activated mouse HSCs, but not in quiescent HSCs or primary hepatocytes from rat. Finally, we provide evidence that the elevated basal level of ER stress in activated HSCs has a role in their susceptibility to the pro-apoptotic effect of CBD. We propose that CBD, by selectively inducing death of activated HSCs, represents a potential therapeutic agent for the treatment of liver fibrosis.

Use of stem cells for liver diseases-current scenario

End-stage liver disease and liver failure are major health problems worldwide leading to high mortality and morbidity and high healthcare costs. Currently, orthotropic liver transplantation is the only effective treatment available to the patients of end-stage liver disease. However, a serious shortage of liver donors, high cost, and risk of organ rejection are the major obstacles to liver transplantation. Because of the ability of stem cells for differentiation into any tissue type, they have huge potential in therapy of various end-stage or degenerative diseases and traumatic injuries. Stem cell therapy has the potential to provide a valuable adjunct and alternative to liver transplantation and has immense potential in the management of end stage liver disease and liver failure. Stem cell therapy can be mediated by either a direct contribution to the functional hepatocyte population with embryonic, induced pluripotent, or adult stem cells or by promotion of endogenous regenerative processes with bone marrow-derived stem cells. Initial translational studies have been encouraging and have suggested improved liver function in advanced chronic liver disease and enhanced liver regeneration after portal vein embolization and partial hepatic resection. Stem cells infusion in cirrhotic patients has improved liver parameters and could form a viable bridge to transplantation. The present review summarizes basic of stem cell biology relevant to clinicians and an update on recent advances on the management of liver diseases using stem cells.

Increased contractility of hepatic stellate cells in cirrhosis is mediated by enhanced Ca2+-dependent and Ca2+-sensitization pathways

Activation of hepatic stellate cells (HSCs) results in cirrhosis and portal hypertension due to intrahepatic resistance. Activated HSCs increase their contraction after receptor agonist stimulation; however, the signaling pathways for the regulation of contraction are not fully understood. The aim of this study was to elucidate the change in contractile mechanisms of HSCs after cirrhotic activation. The expression pattern of contractile regulatory proteins was analyzed with quantitative RT-PCR and Western blotting. The phosphorylation levels of myosin light chain (MLC), 17-kDa PKC-potentiated protein phosphatase 1 inhibitor protein (CPI-17), and MLC phosphatase targeting subunit 1 (MYPT1) after endothelin-1 (ET-1) stimulation in culture-activated HSCs were measured using phosphorylation-specific antibodies. In vivo-activated HSCs were isolated from rats subjected to bile duct ligation and repeated dimethylnitrosoamine injections. HSCs showed increased expression of not only α-smooth muscle actin, but also the contractile regulatory proteins MLC kinase (MLCK), Rho kinase 2 (ROCK2), and CPI-17 during HSC activation in vitro. In culture-activated HSCs, ET-1 increased phosphorylation of CPI-17 at Thr18, which was markedly inhibited by the PKC inhibitor Ro-31-8425. ET-1 induced phosphorylation of MYPT1 at Thr853, which was suppressed by the ROCK inhibitor Y-27632. ET-1 induced sustained phosphorylation of MLC at Thr18/Ser19, which was inhibited by both Ro-31-8425 and Y-27632. Consistent with the data obtained from the in vitro study, HSCs isolated from cirrhotic rats showed increased expression of α-smooth muscle actin, MLCK, CPI-17, and ROCK2 compared with HSCs from nontreated rats. Furthermore, MLC phosphorylation in in vivo-activated HSCs was increased, according to enhanced phosphorylation of CPI-17 and MYPT1 in the presence of ET-1. These results suggest that activated HSCs may participate in constriction of hepatic sinusoids in the cirrhotic liver through both Ca(2+)-dependent (MLCK pathway) and Ca(2+)-sensitization mechanism (CPI-17 and MYPT1 pathways).

Reduction of fibrogenesis by selective delivery of a Rho kinase inhibitor to hepatic stellate cells in mice

One of the pathways activated during liver fibrosis is the Rho kinase pathway, which regulates activation, migration, and contraction of hepatic stellate cells (HSC). Inhibition of this kinase by the Rho kinase inhibitor Y27632 [(+)-(R)-trans- 4-(1-aminoethyl)-N-(4-pyridyl)cyclohexanecarboxamide dihydrochloride] has been shown to reduce fibrosis in animal models. However, kinase expression is ubiquitous, so any inhibitor may affect many cell types. We hypothesize that cell-specific delivery of a kinase inhibitor will be beneficial. Therefore, we conjugated Y27632 to the carrier mannose-6-phosphate (M6P) human serum albumin (HSA), which is taken up specifically in activated HSC through the M6P/insulin-like growth factor II receptor. This conjugate decreased protein expression of phosphorylated myosin light chain 2 (pMLC2) and vinculin, downstream of Rho kinase, in activated primary HSC and decreased the migration and contraction of HSC. In an ex vivo model, free Y27632 decreased contractility of rat aortas, whereas the Y27-conjugate did not, showing that the Y27-conjugate does not affect nontarget tissue. In chronic CCl(4)-induced liver fibrosis, both free drug and conjugate reduced HSC activation; however, only the Y27-conjugate significantly reduced collagen deposition. Treatment with the Y27-conjugate, but not with free drug, reduced pMLC2 expression in livers 24 h after injection, demonstrating prolonged inhibition of the Rho kinase pathway. The Rho kinase inhibitor Y27632 can be specifically targeted to HSC using M6PHSA, decreasing its effects in nontarget tissues. The targeted drug effectively reduced fibrotic parameters in vivo via the inhibition of the Rho kinase pathway.

Management of liver cirrhosis between primary care and specialists

This article discusses a practical, evidence-based approach to the diagnosis and management of liver cirrhosis by focusing on etiology, severity, presence of complications, and potential home-managed treatments. Relevant literature from 1985 to 2010 (PubMed) was reviewed. The search criteria were peer-reviewed full papers published in English using the following MESH headings alone or in combination: "ascites", "liver fibrosis", "cirrhosis", "chronic hepatitis", "chronic liver disease", "decompensated cirrhosis", "hepatic encephalopathy", "hypertransaminasemia", "liver transplantation" and "portal hypertension". Forty-nine papers were selected based on the highest quality of evidence for each section and type (original, randomized controlled trial, guideline, and review article), with respect to specialist setting (Gastroenterology, Hepatology, and Internal Medicine) and primary care. Liver cirrhosis from any cause represents an emerging health issue due to the increasing prevalence of the disease and its complications worldwide. Primary care physicians play a key role in early identification of risk factors, in the management of patients for improving quality and length of life, and for preventing complications. Specialists, by contrast, should guide specific treatments, especially in the case of complications and for selecting patient candidates for liver transplantation. An integrated approach between specialists and primary care physicians is essential for providing better outcomes and appropriate home care for patients with liver cirrhosis.

AT1R-CB₁R heteromerization reveals a new mechanism for the pathogenic properties of angiotensin II

The mechanism of G protein-coupled receptor (GPCR) signal integration is controversial. While GPCR assembly into hetero-oligomers facilitates signal integration of different receptor types, cross-talk between Gαi- and Gαq-coupled receptors is often thought to be oligomerization independent. In this study, we examined the mechanism of signal integration between the Gαi-coupled type I cannabinoid receptor (CB(1)R) and the Gαq-coupled AT1R. We find that these two receptors functionally interact, resulting in the potentiation of AT1R signalling and coupling of AT1R to multiple G proteins. Importantly, using several methods, that is, co-immunoprecipitation and resonance energy transfer assays, as well as receptor- and heteromer-selective antibodies, we show that AT1R and CB(1)R form receptor heteromers. We examined the physiological relevance of this interaction in hepatic stellate cells from ethanol-administered rats in which CB(1)R is upregulated. We found a significant upregulation of AT1R-CB(1)R heteromers and enhancement of angiotensin II-mediated signalling, as compared with cells from control animals. Moreover, blocking CB(1)R activity prevented angiotensin II-mediated mitogenic signalling and profibrogenic gene expression. These results provide a molecular basis for the pivotal role of heteromer-dependent signal integration in pathology.

Noninvasive tools to assess liver disease

PURPOSE OF REVIEW

To improve understanding of recent developments in the noninvasive assessment of fibrosis and their potential clinical application to a range of chronic liver diseases.

RECENT FINDINGS

Many noninvasive tests have evolved from their primary validation in chronic hepatitis C virus (HCV) infection to integration into clinical management algorithms for chronic liver disease of varying cause. Recent studies consider the use of these techniques in sequence or in combination, and compare the performance of serum and imaging-based noninvasive techniques to identify patients with significant fibrosis, or those at most risk of clinical sequelae from advanced-stage disease. Methods developed in chronic hepatitis C have now been applied in different chronic liver diseases, including nonalcoholic fatty liver disease, alcoholic liver disease, HIV/HCV co-infection and primary biliary cirrhosis. A number of new management algorithms have been developed to facilitate the integration of noninvasive techniques into clinical practice.

SUMMARY

Noninvasive tools to assess liver diseases continue to evolve. New imaging technologies have been developed. Existing biomarkers and imaging modalities have been better integrated into clinical practice algorithms, and applied to different chronic liver diseases. Noninvasive techniques will likely continue to be refined and play an important role in the future management of patients with chronic liver disease.

Tissue transglutaminase does not affect fibrotic matrix stability or regression of liver fibrosis in mice

BACKGROUND & AIMS

The ubiquitous cross-linking enzyme tissue transglutaminase (TG2) has been implicated in irreversible collagen stabilization in liver fibrosis, although functional evidence is lacking. We studied the contribution of TG2 to hepatic fibrotic matrix stability, as well as liver fibrosis progression and regression in TG2-deficient mice.

METHODS

Advanced liver fibrosis was induced by carbon tetrachloride or thioacetamide in TG2(-/-) mice and their wild-type littermates to study fibrosis progression and its spontaneous regression for up to 36 weeks. Pattern and extent of fibrosis were analyzed by histology and hepatic hydroxyproline quantification. Dynamic changes in hepatic matrix cross-linking were assessed by stepwise collagen extraction. Expression of 7 TGs and fibrosis-related genes was determined by quantitative reverse-transcription polymerase chain reaction.

RESULTS

Transglutaminase activity was increased in fibrosis, and the level of TG2 messenger RNA correlated with the expression of fibrosis-related genes. Biochemical analysis revealed progressive collagen stabilization, with an up to 6-fold increase in the highly cross-linked, pepsin-insoluble fraction (26%). In TG2(-/-) mice, hepatic TG activity was significantly decreased, but chronic administration of carbon tetrachloride or thioacetamide led to a comparable extent and pattern of liver fibrosis, as in wild-type mice. In TG2(-/-) mice, the composition of hepatic collagen fractions and levels of fibrosis-related transcripts were unchanged, and fibrosis reversal was not facilitated.

CONCLUSIONS

TG2 and TG activity are up-regulated during hepatic fibrosis progression, but do not contribute to fibrogenesis or stabilization of the collagen matrix. TG2 deletion does not promote regression of liver fibrosis. TG2-independent collagen cross-linking is a remarkable feature of progressing hepatic fibrosis and represents an important therapeutic target for liver fibrosis.

Constitutional telomerase mutations are genetic risk factors for cirrhosis

Some patients with liver disease progress to cirrhosis, but the risk factors for cirrhosis development are unknown. Dyskeratosis congenita, an inherited bone marrow failure syndrome associated with mucocutaneous anomalies, pulmonary fibrosis, and cirrhosis, is caused by germline mutations of genes in the telomerase complex. We examined whether telomerase mutations also occurred in sporadic cirrhosis. In all, 134 patients with cirrhosis of common etiologies treated at the Liver Research Institute, University of Arizona, between May 2008 and July 2009, and 528 healthy subjects were screened for variation in the TERT and TERC genes by direct sequencing; an additional 1,472 controls were examined for the most common genetic variation observed in patients. Telomere length of leukocytes was measured by quantitative polymerase chain reaction. Functional effects of genetic changes were assessed by transfection of mutation-containing vectors into telomerase-deficient cell lines, and telomerase activity was measured in cell lysates. Nine of the 134 patients with cirrhosis (7%) carried a missense variant in TERT, resulting in a cumulative carrier frequency significantly higher than in controls (P = 0.0009). One patient was homozygous and eight were heterozygous. The allele frequency for the most common missense TERT variant was significantly higher in patients with cirrhosis (2.6%) than in 2,000 controls (0.7%; P = 0.0011). One additional patient carried a TERC mutation. The mean telomere length of leukocytes in patients with cirrhosis, including six mutant cases, was shorter than in age-matched controls (P = 0.0004).

CONCLUSION

Most TERT gene variants reduced telomerase enzymatic activity in vitro. Loss-of-function telomerase gene variants associated with short telomeres are risk factors for sporadic cirrhosis.

A fibronectin-independent mechanism of collagen fibrillogenesis in adult liver remodeling

BACKGROUND & AIMS

Fibrosis is an abnormal extension of the wound healing process that follows tissue damage; it is involved in pathogenesis in a variety of chronic diseases. The formation of extracellular matrix is an essential response in wound healing. Although it has been proposed that collagen organization and assembly depend on the fibronectin matrix in culture, the contribution of fibronectin to these processes remains to be defined in vivo.

METHODS

We generated a conditional, fibronectin-deficient mouse model of liver injury and explored whether fibronectin would be a suitable target for preventing extensive collagen deposits and scar formation that could lead to liver fibrosis.

RESULTS

The lack of fibronectin did not interfere with reconstruction of collagen fibril organization in response to liver injury. Signaling by transforming growth factor-β and type V collagen were required for collagen fibrillogenesis during remodeling of adult liver tissue.

CONCLUSIONS

Transforming growth factor-β and type V collagen are targets for regulating the initial fibrogenic response to liver damage.

Occlusive portal vein thrombosis as a new marker of decompensated cirrhosis

Natural history of liver cirrhosis is divided into compensated and decompensated stage. Traditionally, the markers of decompensated cirrhosis include ascites, variceal hemorrhage, hepatic encephalopathy and jaundice. The clinical importance of portal vein thrombosis (PVT) is increasingly recognized in patients with liver cirrhosis. The presence of PVT is not only an independent predictor of failure to control active variceal bleeding and prevent variceal rebleeding, but also significantly associated with increased mortality in patients with liver cirrhosis. Besides, it greatly influences the technical success and outcome of endovascular interventional treatment and liver transplantation for liver cirrhosis and its secondary portal hypertension. Thus, we hypothesize that PVT should be regarded as a critical marker of decompensated cirrhosis, whether clinical events such as the development of ascites, encephalopathy, and variceal bleeding occur or not. Our hypothesis adds PVT into the definition of decompensated cirrhosis and reminds clinicians and investigators that PVT plays a vital role in natural history of liver cirrhosis. Further, it is essential to construct a new system of preventing and treating liver cirrhosis in the presence of PVT.

Increased liver uptake and reduced hepatic stellate cell activation with a cell-specific conjugate of the Rho-kinase inhibitor Y27632

Purpose

Rho-kinase regulates activation of hepatic stellate cells (HSC) during liver fibrosis, but the ubiquitous presence of this kinase may hinder examination of its exact role and the therapeutic use of inhibitors. We therefore coupled the Rho-kinase inhibitor Y27632 to a drug carrier that binds the mannose-6-phosphate insulin-like growth factor II (M6P/IGFII)-receptor which is upregulated on activated HSC.

Methods

Y27632 was coupled to mannose-6-phosphate human serum albumin (M6PHSA), and in vitro experiments were performed on primary rat HSC. Biodistribution and effect studies were performed in an acute CCl₄ model in mice.

Results

Y27-conjugate remained stable in serum, while drug was efficiently released in liver homogenates. Receptor-blocking studies revealed that it was specifically taken up through the M6P/IGFII-receptor on fibroblasts, and it inhibited expression of fibrotic markers in activated HSC. In vivo, liver drug levels were significantly higher after injection of Y27-conjugate as compared to Y27632, and the conjugate accumulated specifically in HSC. After acute CCl₄-induced liver injury, Y27-conjugate reduced the local activation of HSC, whereas an equimolar dose of free drug did not.

Conclusions

We conclude that specific targeting of a Rho-kinase inhibitor to HSC leads to enhanced accumulation of the drug in HSC, reducing early fibrogenesis in the liver.

Electronic Supplementary Material

The online version of this article (doi:10.1007/s11095-011-0430-9) contains supplementary material, which is available to authorized users.

Stem cells in clinical practice: applications and warnings

Stem cells are a relevant source of information about cellular differentiation, molecular processes and tissue homeostasis, but also one of the most putative biological tools to treat degenerative diseases. This review focuses on human stem cells clinical and experimental applications. Our aim is to take a correct view of the available stem cell subtypes and their rational use in the medical area, with a specific focus on their therapeutic benefits and side effects. We have reviewed the main clinical trials dividing them basing on their clinical applications, and taking into account the ethical issue associated with the stem cell therapy.

Human T cell microparticles circulate in blood of hepatitis patients and induce fibrolytic activation of hepatic stellate cells

Microparticles (MPs) are small cell membrane vesicles that are released from cells during apoptosis or activation. Although circulating platelet MPs have been studied in some detail, the existence and functional role of T cell MPs remain elusive. We show that blood from patients with active hepatitis C (alanine aminotransferase [ALT] level >100 IU/mL) contains elevated numbers of T cell MPs compared with patients with mild hepatitis C (ALT <40 IU/mL) and healthy controls. T cell MPs fuse with cell membranes of hepatic stellate cells (HSCs), the major effector cells for excess matrix deposition in liver fibrosis and cirrhosis. MP uptake is partly intercellular adhesion molecule 1-dependent and leads to activation of nuclear factor kappa B and extracellular signal-regulated kinases 1 and 2 and subsequent up-regulation of fibrolytic genes in HSCs, down-regulation of procollagen α1(I) messenger RNA, and blunting of profibrogenic activities of transforming growth factor β1. Ex vivo, the induced fibrolytic activity is evident in MPs derived from activated CD4+ T cells and is highest in MPs derived from activated and apoptotic CD8+ T cells. Mass spectrometry, fluorescence-activated cell sorting analysis, and function blocking antibodies revealed CD147/Emmprin as a candidate transmembrane molecule in HSC fibrolytic activation by CD8+ T cell MPs.

CONCLUSION

Circulating T cell MPs are a novel diagnostic marker for inflammatory liver diseases, and in vivo induction of T cell MPs may be a novel strategy to induce regression of liver fibrosis.

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.

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.

[Hepatocellular carcinoma and cholangiocarcinoma]

Hepatocellular carcinoma and cholangiocarcinoma are relatively rare tumors of the gastrointestinal tract in western Europe but their incidence has been increased in recent years. Newly diagnosed intrahepatic lesions or intrahepatic cholestasis require extensive laboratory tests and imaging studies in order to confirm the diagnosis of hepatocellular carcinoma, intrahepatic or extrahepatic cholangiocarcinoma. The treatment options range from liver resection or liver transplantation to conservative measures (in cases of non-resectable lesions). This review article aims to provide an overview on the diagnostic options and the subsequent treatment.

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.

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.

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.

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.

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.

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.

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.

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.