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Treatment of hepatorenal syndromes (HRSs) is currently based on vasopressin analogs. The aim of this pilot study was to evaluate the efficacy and safety of noradrenalin (NA) in the treatment of type 1 HRS. Between 1998 and 2000, 12 consecutive patients with type 1 HRS (7 men, 5 women; mean age, 54 +/- 11 years; mean Child-Pugh score, 11.3 +/- 1.7) were treated with intravenous NA (0.5-3 mg/h), in combination with intravenous albumin and furosemide. NA was given for 10 +/- 3 days, at a mean dose of 0.8 +/- 0.3 mg/h. Reversal of HRS was observed in 10 of 12 patients (83%; 95% confidence interval, 52%-98%) after a median of 7 days (range, 5-10 days). Serum creatinine levels fell from 358 +/- 161 to 145 +/- 78 micromol/L (P

The aim of this study was to assess the usefulness of nitric oxide (NO) output measurement at multiple expiratory flow rates during diseases characterized by increased exhaled NO (FE(NO)) that could come from alveolar (liver cirrhosis) or bronchial (asthma) sources. It has been proposed that NO output measurements expressed as a function of expiratory flow allow alveolar NO concentration (FA(NO)) and maximal bronchial NO output (Qbr,max (NO)) to be computed. In 36 healthy nonsmoking subjects, we found that maximal bronchial NO output (37 +/- 3 nl/min) was correlated with the height of the subjects (p = 0.02). Alveolar NO concentration was 5.1 +/- 0.3 (SEM) ppb, which represented 31 +/- 2% and 61 +/- 3% of FE(NO) at 50 and 200 ml/s expiratory flow rate, respectively. Nonsmoking subjects with asthma (n = 28) were characterized by an increase in Qbr,max (NO) (133 +/- 14 nl/min) as compared with healthy nonsmoking subjects (p0.0001). FE(NO)50, FE(NO)200, and Qbr,max (NO) were equally efficient in differentiating subjects with asthma from healthy subjects. Patients with liver cirrhosis (n = 26, 14 smokers and 12 nonsmokers) had an increased FA(NO) compared with healthy subjects (cirrhosis: 8.3 +/- 0.9 ppb, healthy nonsmokers [n = 36] and smokers [n = 20], n = 56: 4.7 +/- 0.3 ppb, p0.05), which was correlated with the alveolar-arterial oxygen difference (p = 0.007). FA(NO) and FE(NO)200, but not FE(NO)50 values, allowed patients with liver cirrhosis to be differentiated from healthy subjects. These results suggest that a two-compartment model for NO output allows the increase in FE(NO) from alveolar sources to be differentiated from the increase from bronchial sources.

Background & Aims: Liver X receptors (LXRs) are lipid- activated nuclear receptors with important roles in cholesterol trans- port, lipogenesis, and anti-inflammatory signaling. Hepatic stellate cells activate during chronic liver injury and mediate the fibrotic response. These cells are also major repositories for lipids, but the role of lipid metabolism during stellate cell activation remains unclear. We investigated the role of LXR signaling stellate cell activa- tion and susceptibility to fibrotic liver disease. Methods: Immortalized and primary stellate cells purified from mice were treated with highly specific LXR ligands. Carbon tetrachloride and methionine/choline deficiency were used as chronic liver injury models. Reciprocal bone marrow transplants were performed to test the importance of hematopoietically derived cells to the fibrotic response. Results: LXR ligands suppressed markers of fibrosis and stellate cell activation in primary mouse stellate cells. Lxrab(� /� ) stellate cells produce increased levels of inflammatory mediators, and conditioned media from Lxrab(� /� ) cells increases the fibrogenic program of wild-type cells. Furthermore, Lxrab(� /� ) stellate cells exhibit altered lipid morphology and increased expression of fibrogenic genes, sug- gesting they are primed for activation. In vivo, Lxrab(� /� ) mice have marked susceptibility to fibrosis in two injury models. Bone marrow transplants point to altered stellate cell function, rather than hema- topoietic cell inflammation, as the primary basis for the Lxrab(� /� ) phenotype. Conclusions: These results reveal an unexpected role for LXR signal- ing and lipid metabolism in the modulation of hepatic stellate cell function.

Hepatic myofibroblasts (hMFs) play a key role in the development of liver fibrosis associated with chronic liver diseases. Apoptosis of these cells is emerging as a key process in the resolution of liver fibrosis. Here, we examined the effects of cyclopentenone prostaglandins on apoptosis of human hMFs. Cyclopentenone prostaglandins of the J series markedly reduced hMF viability, with 15-deoxy-Delta(12,14)-prostaglandin J2 (15-d-PGJ2) being the most potent. This effect was independent of peroxisome-proliferator-activated receptors (PPARs), because PPARgamma and PPARalpha agonists did not affect hMF cell viability, and PPARgamma, the nuclear receptor for 15-d-PGJ2, was not expressed in hMFs. Moreover, 15-d-PGJ2 did not act via a cell surface G protein-coupled receptor, as shown in guanosine-5'-O-(3-thiotriphosphate) binding assays. Cell death resulted from an apoptotic process, because 15-d-PGJ2-treated hMFs exhibited condensed nuclei, fragmented DNA, and elevated caspase-3 activity. Moreover, the caspase inhibitor Z-Val-Ala-Asp(OCH3)-fluoromethyl ketone blocked the cytotoxic effect of 15-d-PGJ2. The apoptotic effects of 15-d-PGJ2 were reproduced by H2O2 and blocked by the antioxidants N-acetylcysteine (NAC), N-(2-mercapto-propionyl)-glycine (NMPG) and pyrrolidine dithiocarbamate (PDTC). Accordingly, 15-d-PGJ2 generated rapid production of reactive oxygen species in hMFs, via a NAC/NMPG/PDTC-sensitive pathway. In conclusion, 15-d-PGJ2 induces apoptosis of human hMFs via a novel mechanism involving oxidative stress and unrelated to activation of its nuclear receptor PPARgamma. These data underline the antifibrogenic potential of 15-d-PGJ2.

Proliferation of hepatic myofibroblasts (hMF) is central for the development of fibrosis during liver injury, and factors that may limit their growth are potential antifibrotic agents. Sphingosine 1-phosphate (S1P) is a bioactive sphingolipid with growth-regulating properties, either via Edg receptors or through intracellular actions. In this study, we examined the effects of S1P on the proliferation of human hMF. Human hMF expressed mRNAs for the S1P receptors Edg1, Edg3, and Edg5. These receptors were functional at nanomolar concentrations and coupled to pertussis toxin-sensitive and -insensitive G proteins, as demonstrated in guanosine 5′-3-O-(thio)triphosphate binding assays. S1P potently inhibited hMF growth (IC50 = 1 μm), in a pertussis toxin-insensitive manner. Analysis of the mechanisms involved in growth inhibition revealed that S1P rapidly increased prostaglandin E2 production and in turn cAMP, two growth inhibitory messengers for hMF; C2-ceramide and sphingosine, which inhibited hMF proliferation, did not affect cAMP levels. Production of cAMP by S1P was abolished by NS-398, a selective inhibitor of COX-2. Also, S1P potently induced COX-2 protein expression. Blocking COX-2 by NS-398 blunted the antiproliferative effect of S1P. We conclude that S1P inhibits proliferation of hMF, probably via an intracellular mechanism, through early COX-2-dependent release of prostaglandin E2 and cAMP, and delayed COX-2 induction. Our results shed light on a novel role for S1P as a growth inhibitory mediator and point out its potential involvement in the negative regulation of liver fibrogenesis.

Cigarette smoke exposure, whether passive or active, carries a high disease burden worldwide [1]. In a recent comprehensive assessment of the mortality attributable to modifiable risk factors in the US adult population, tobacco use was held responsible for 467,000 deaths (approximately one out of five) in 2005 [2]. Despite the large body of evidence documenting the pluriorgan morbidity of tobacco, reports investigating the impact of cigarette smoking on pathogenesis of liver injury have long remained scant. Initial evidence arose from two retrospective studies suggesting that cigarette smoking may increase prevalence and/or severity of alcoholic [3] and HBV-related cirrhosis [4]. Accordingly, two recent studies in patients with primary biliary cirrhosis identified tobacco use as an independent predictor of advanced fibrosis at presentation [5,6]. In contrast, in patients with chronic hepatitis C, the impact of tobacco use on fibrosis progression remains controversial [7,8] and available data would suggest that cigarette smoking may aggravate necroinflammation, thereby contributing to accelerated fibrogenesis [7–10]. Finally, in line with the carcinogenic properties of tobacco in several organs, a number of studies indicate that cigarette smoking is associated with an increased incidence of hepatocellular carcinoma in cirrhotic patients [11–14]. Non-alcoholic fatty liver disease (NAFLD), the hepatic hallmark of the metabolic syndrome, is a worrisome

Matrix metalloproteinase-2 (MMP-2) is involved in extracellular matrix remodeling. It is secreted as a proenzyme and activated by membrane type-MMPs (MT-MMP), such as MT1-MMP. In liver fibrosis, MMP-2 is highly expressed in myofibroblasts and may have a profibrogenic role. The mechanisms of its activation in the liver are still unclear. The aim of this work was to show that pro-MMP-2 is efficiently activated in human fibrotic liver and to investigate the role of cell-matrix interactions in this process. Liver specimens obtained from patients with active cirrhosis were compared to normal liver specimens. Human hepatic myofibroblasts were cultured either on plastic, fibronectin, laminin, or on collagen I gels. MMP-2 activity was visualized by gelatin zymography. MMP-2 active form (59 kd) was detected in active cirrhosis but not in normal liver. Myofibroblasts cultured on plastic, fibronectin, or laminin predominantly expressed inactive pro-MMP-2 (66 kd). In contrast, myofibroblasts cultured on collagen I markedly activated the enzyme. Similar results were obtained using membrane fractions from cells previously cultured on collagen or plastic. Activation was inhibited by the tissue inhibitor of metalloproteinases-2 but not by tissue inhibitor of metalloproteinases-1, implicating a MT-MMP-mediated process. Culture on collagen I up-regulated MT1-MMP protein detected by Western blotting, but decreased MT1-MMP mRNA. This study shows that MMP-2 is activated in fibrotic liver. It suggests that interactions between collagen I and myofibroblasts promote this process through a post-translational increase of MT1-MMP expression in these cells.

During chronic liver diseases, hepatic stellate cells (HSC) acquire a myofibroblastic phenotype, proliferate, and synthetize fibrosis components. Myofibroblastic HSC (mHSC) also participate to the regulation of intrahepatic blood flow, because of their contractile properties. Here, we examined whether human mHSC express natriuretic peptide receptors (NPR). Only NPR-B mRNA was identified, which was functional as demonstrated in binding studies and by increased cGMP levels in response to C-type natriuretic peptide (CNP). CNP inhibited mHSC proliferation, an effect blocked by the protein kinase G inhibitor 8-(4 chlorophenylthio)-cGMP and by the NPR antagonist HS-142-1 and reproduced by analogs of cGMP. Growth inhibition was associated with a reduction of extracellular signal-regulated kinase and c-Jun N-terminal kinase and with a blockade of AP-1 DNA binding. CNP and cGMP analogs also blunted mHSC contraction elicited by thrombin, by suppressing calcium influx. The relaxing properties of CNP were mediated by a blockade of store-operated calcium channels, as demonstrated using a calcium-free/calcium readdition protocol. These results constitute the first evidence for a hepatic effect of CNP and identify mHSC as a target cell. Activation of NPR-B by CNP in human mHSC leads to inhibition of both growth and contraction. These data suggest that during chronic liver diseases, CNP may counteract both liver fibrogenesis and associated portal hypertension.

The cannabinoid system comprises specific G protein-coupled receptors (CB1 and CB2), exogenous (marijuana-derived cannabinoids) and endogenous (endocannabinoids) ligands, and a machinery dedicated to endocannabinoid synthesis and degradation. Studies over two decades have extensively documented the crucial role of the cannabinoid system in the regulation of a variety of pathophysiological conditions. However, its role in liver pathology has only been recently unravelled, probably given the low expression of CB1 and CB2 in the normal liver. We have recently demonstrated that CB1 and CB2 receptors display opposite effects in the regulation of liver fibrogenesis during chronic liver injury. Indeed, both receptors are up-regulated in the liver of cirrhotic patients, and expressed in liver fibrogenic cells. Moreover, CB1 receptors are profibrogenic and accordingly, the CB1 antagonist rimonabant reduces fibrosis progression in three experimental models. In keeping with these results, daily cannabis smoking is a risk factor for fibrosis progression in patients with chronic hepatitis C. In contrast, CB2 display antifibrogenic effects, by a mechanism involving reduction of liver fibrogenic cell accumulation. These results may offer new perspectives for the treatment of liver fibrosis, combining CB2 agonist and CB1 antagonist therapy.

Proliferation of myofibroblastic hepatic stellate cells (HSC) in response to growth factors is essential for the development of liver fibrosis. We have reported that prostaglandins (PG) and cyclic AMP (cAMP) inhibit growth of human HSC. This PG/cAMP pathway transduces the endothelin (ET) B-mediated antiproliferative effect of endothelin-1 (ET-1) and up-regulates ETB receptors. Here, we show that platelet-derived growth factor (PDGF)-BB and thrombin, although mitogenic, generate growth inhibitory PGE2 in myofibroblastic human HSC. The two peptides elicit early PGE2 and cAMP synthesis, and also promote delayed induction of cyclooxygenase (COX)-2. Both early and delayed production of PGE2 counteract the mitogenic effect of PDGF-BB and thrombin because: (i) pretreatment with the COX inhibitor ibuprofen markedly enhances the mitogenic effect of both peptides; (ii) blocking early synthesis of PGE2 greatly enhances extracellular signal-regulated kinase (ERK) activation by both growth factors; (iii) enhancement of DNA synthesis by ibuprofen is only lost when the inhibitor is added after COX-2 induction has occurred. Finally, PDGF-BB and thrombin raise ETB receptors through the PG pathway. Thus, ibuprofen blunts growth factor-induced increase in ETB receptors. Up-regulation of the growth inhibitory ETB receptors by both mitogens may enhance the antiproliferative effect of ET-1 and thereby establish a negative feedback of their mitogenic effect. Our results shed light on novel growth inhibitory signals evoked by two mitogenic growth factors expressed during liver injury.

During chronic liver diseases, hepatic stellate cells (HSC) acquire an activated myofibroblast-like phenotype and proliferate and synthesize fibrosis components. Endothelin-1 (ET-1), which inhibited the growth of human myofibroblastic HSC, increased the formation of two NF-κB DNA binding complexes; this effect was also observed with tumor necrosis factor-α (TNF-α). The complexes were identified as the p50/p50 and p50/p65 NF-κB dimers. Activation of NF-κB was associated with the degradation of the inhibitory protein IκB-α; no IκB-β was detected. Activation of NF-κB and degradation of IκB-α were prevented by the NF-κB inhibitors sodium salicylate and MG-132. In addition to cyclooxygenase-1 (COX-1), COX-2 is also constitutively expressed in human HSC, and the use of dexamethasone and of SC-58125, a selective COX-2 inhibitor, revealed that COX-2 accounts for basal COX activity. Moreover, COX-2 mRNA and protein were up-regulated by ET-1 and TNF-α, whereas COX-1 was unaffected. Induction of COX-2 and stimulation of COX activity by ET-1 and TNF-α were prevented by sodium salicylate and MG-132, suggesting that activation of NF-κB by either factor is needed for stimulation of COX-2. Finally, SC-58125 and dexamethasone reduced the growth inhibitory effect of ET-1 and TNF-α, indicating that activation of COX-2 is required for inhibition of HSC proliferation. Taken together, our results suggest that NF-κB, by inducing COX-2 expression, may play an important role in the negative regulation of human myofibroblastic HSC proliferation.

Background/Aims: The number of perisinusoidal myofibroblasts has been shown to be increased in hepatocellular carcinoma, as compared to cirrhosis. This increase might suggest a cooperative relationship between tumour cells and myofibroblasts. To assess this relationship, we undertook: (a) a immunohistochemical study to confirm the existence of an increased number of perisinusoidal myofibroblasts in human hepatocellular carcinoma, as compared to cirrhosis with or without liver cell dysplasia, (b) an in vitro study testing the role of normal or tumoral human hepatocytes in myofibroblast proliferation. Methods: Forty explanted cirrhotic livers, including 14 with hepatocellular carcinoma and 24 with liver cell dysplasia, were studied. Myofibroblasts were detected by immunohistochemistry using an antibody directed against alpha-smooth muscle actin. Hepatic myofibroblasts in culture were obtained by outgrowth from human liver explants. Results: There was a progressive increase in the number of perisinusoidal myofibroblasts, from cirrhotic nodules without dysplasia to liver cell dysplasia and hepatocellular carcinoma. Conditioned medium from isolated normal human hepatocytes had only minor mitogenic effects on myofibroblasts, as assessed by measuring DNA synthesis and cell growth. In contrast, conditioned medium from a human hepatoma cell line (HepG2 cells) markedly stimulated the proliferation of human myofibroblasts. This mitogenic activity was stored in HepG2 cells and secreted in the extracellular medium rather than being simply released following cell lysis. Conclusion: These results suggest that the increased number of myofibroblasts in hepatocellular carcinoma might be due to a paracrine mechanism involving soluble mitogenic factor(s) secreted by tumour cells.

International audience; Liver fibrosis is the common scarring reaction associated with chronic liver injury that results from prolonged parenchymal cell injury and/or inflammation. The fibrogenic response is characterized by progressive accumulation of extracellular matrix components enriched in fibrillar collagens and a failure of matrix turnover. This process is driven by a heterogeneous population of hepatic myofibroblasts, which mainly derive from hepatic stellate cells and portal fibroblasts. Regression of fibrosis can be achieved by the successful control of chronic liver injury, owing to termination of the fibrogenic reaction following clearance of hepatic myofibroblasts and restoration of fibrolytic pathways. Understanding of the complex network underlying liver fibrogenesis has allowed the identification of a large number of antifibrotic targets, but no antifibrotic drug has as yet been approved. This review will highlight recent advances regarding the mechanisms that regulate liver fibrogenesis and fibrosis regression, with special focus on novel signaling pathways and the role of inflammatory cells. Translation of these findings to therapies will require continued efforts to develop multitarget therapeutic approaches that will improve the grim prognosis of liver cirrhosis.

Alcoholic and nonalcoholic fatty liver disease (ALD and NAFLD) are the predominant causes of liver-related mortality in Western countries. We have shown that limiting classical (M1) Kupffer cell (KC) polarization reduces alcohol-induced liver injury. Herein, we investigated whether favoring alternatively activated M2 KCs may protect against ALD and NAFLD. Ongoing alcohol drinkers and morbidly obese patients, with minimal hepatic injury and steatosis, displayed higher hepatic expression of M2 genes, as compared to patients with more severe liver lesions; individuals with limited liver lesions showed negligible hepatocyte apoptosis but significant macrophage apoptosis. Experiments in mouse models of ALD or NAFLD further showed that BALB/c or resveratrol-treated mice fed alcohol or a high-fat diet displayed preponderant M2 KC polarization, M1 KC apoptosis, and resistance to hepatocyte steatosis and apoptosis, as compared to control C57BL6/J mice. In vitro experiments in isolated KC, peritoneal, and Raw264.7 macrophages demonstrated that M1 macrophage apoptosis was promoted by conditioned medium from macrophages polarized into an M2 phenotype by either interleukin (IL)4, resveratrol, or adiponectin. Mechanistically, IL10 released from M2 cells promoted M1 death, and anti-IL10 antibodies blunted the proapoptic effects of M2-conditioned media. IL10 secreted by M2 KCs promoted selective M1 death by a mechanism involving activation of arginase in high inducible nitric oxide synthase-expressing M1 KCs. In alcohol-exposed mice, neutralization of IL10 impaired M1 apoptosis.These data uncover a novel mechanism regulating the M1/M2 balance that relies on apoptotic effects of M2 KCs towards their M1 counterparts. They suggest that promoting M2-induced M1 KC apoptosis might prove a relevant strategy to limit alcohol- and high fat-induced inflammation and hepatocyte injury.

During chronic liver diseases, hepatic stellate cells (HSC) acquire an activated myofibroblast-like phenotype, proliferate, and synthetize fibrosis components. We have shown that endothelin-1 (ET-1) inhibits the proliferation of activated human HSC via endothelin B (ETB) receptors. We now investigate the transduction pathway involved in the growth inhibitory effect of ET-1 in activated HSC. Endothelin-1 and the ETB receptor agonist, sarafotoxin-S6C, increased synthesis of PGI2 and PGE2, leading to elevation of cAMP. The cyclooxygenase inhibitor ibuprofen and the adenylyl cyclase inhibitor SQ22536 both blunted the growth inhibitory effect of ET-1. Analysis of early steps associated with growth inhibition indicated that: (a) similar to ET-1, forskolin decreased c-jun mRNA induction without affecting c-fos and krox 24 mRNA expression; (b) ET-1, sarafotoxin-S6C, as well as forskolin, reduced activation of both c-Jun kinase and extracellular signal-regulated kinase. Finally, forskolin, PGI2, and PGE2 raised by fivefold the number of ET binding sites after 6 h, and increased the proportion of ETB receptors from 50% in control cells to 80% in treated cells. In conclusion, ET-1 inhibits proliferation of activated HSC via ETB receptors, through a prostaglandin/cAMP pathway that leads to inhibition of both extracellular signal-regulated kinase and c-Jun kinase activities. Upregulation of ETB receptors by prostaglandin/cAMP raises the possibility of a positive feedback loop that would amplify the growth inhibitory response. These results suggest that ET-1 and agents that increase cAMP might be of interest to limit proliferation of activated HSC during chronic liver diseases.

N I 1988, Y~agisawa et ai. isolated a potent vasoconstricting peptide from the supematant of bovine endotheiial ceils, and named it endotbeiin1 (ET1) (1). Besides vasoregulatory effects in numerous vascular beds, ET-i and related peptides, ET-2 and ET-3, were soon shown to elicit a wide variety of biological effects, such as hormone secretion, positive ino~opism, bronchocons~ction, etc. (24). It was initially shown that the liver is a target tissue for endotheiins by demonstrating that the peptides increase portal pressure and activate giycogenoiysis (5,6). Subsequently, a flurry of papers have investigated vasocontractile effects of ET-i in the normal liver (79), while evidence has accumulated to show that the peptide may play a role in the pa~ogenesis of circulatory disorders observed during liver diseases, such as portal hypertension or ischemia/reperfusion injury (10-15). At the same time, the identification of several non-vascular hepatic effects of the peptide raised the question of their role in other facets of liver disease such as cholestasis or liver fibrogenesis (5,6,1621). This review will focus on these various aspects, after a brief overview of the general properties of endothelin peptides.

Background & Aims: During liver fibrogenesis, myofibroblastic liver cells proliferate and synthesize components of fibrosis. Fibroblast growth factor 2 (FGF-2) is expressed in vivo in myofibroblastic liver cells (MFLCs) during fibrogenesis, and exogenous FGF-2 is mitogenic for MFLCs. The aim of this study was to study the expression and role of endogenous FGF-2 in cultured human MFLCs. Methods: FGF-2 and FGF-2 receptors were studied using immunoblotting. All RNA studies used ribonuclease protection. Growth of MFLCs was studied using [ 3 H]thymidine incorporation and direct cell counting. Results: MFLCs expressed FGF-2 and its receptors FGF receptor 1 and FGF receptor 2. An antibody to FGF-2 blocked the mitogenic effect of transforming growth factor β1 (TGF-β1) for MFLCs but not TGF-β1-induced increase in cellular fibronectin messenger RNA (mRNA). TGF-β1 increased levels of FGF-2 and FGF receptor mRNAs in MFLCs. We have previously shown that TGF-β1 also increased platelet-derived growth factor (PDGF) A chain mRNA in these cells and that anti-PDGF antibody blunted the mitogenic effect of TGF-β1. The present results show that anti-FGF-2 and anti-PDGF-AA are not additive and that FGF-2 and PDGF-AA are not sequentially induced by TGF-β1. Conclusions: FGF-2 mediates the mitogenic but not the profibrogenic effect of TGF-β1 for human MFLCs, and autocrine FGF-2 and PDGF-A interact in the mediation of the mitogenic effect of TGF-β1.

Antihepatitis C virus (HCV) IgM antibodies were found in patients with both acute and chronic hepatitis C. The aims of the study were to determine the significance, in terms of liver disease and virological parameters, of anti-HCV core IgM antibodies in the serum of patients with chronic hepatitis C, and the possible relationship between the presence of these antibodies before treatment and biochemical and virological responses to interferon therapy. Sixty-one patients with chronic hepatitis C were studied. Tests for serum anti-HCV core IgM antibodies were carried out before treatment. The patients received 3 mega units of interferon alpha-2a subcutaneously thrice weekly for at least 3 months (6 months when alanine aminotransferase activity was normal at month 3). A biochemical response to interferon therapy was defined as normal alanine aminotransferase activity at the end of treatment (month 6: biochemical response) and 6 months later (month 12: sustained biochemical response). A sustained virological response was defined as serum HCV RNA negativity by a polymerase chain reaction-based detection method (PCR) in patients with normal alanine aminotransferase at month 12. Anti-HCV core IgM antibodies were detected in 28 of the 61 patients (46%). The prevalence of these antibodies was significantly higher in patients infected with HCV genotype 1 (including subtypes 1a and 1b) than in patients infected with other genotypes (including 2a and 3a) (57% vs. 17%; P < 0.01). No significant difference was found between IgM-positive and IgM-negative patients as regards the mean age, sex ratio, serum alanine aminotransferase and gamma-glutamyl transpeptidase activities, the prevalence of cirrhosis in liver biopsy specimens, detection of HCV RNA by PCR, and quantitation by branched DNA assay. At month 6 of interferon therapy, normal alanine aminotransferase activity was significantly more frequent in IgM-negative than in IgM-positive patients (52% vs. 21%, respectively; P < 0.02). At month 12, normal alanine aminotransferase activity and PCR negativity were significantly more frequent in IgM-negative than in IgM-positive patients (18% vs. 0%, P < 0.04). It is concluded that anti-HCV core IgM antibodies in serum are significantly more frequent in patients infected by HCV type 1 than by other types. This suggests that their overall prevalence in patients with chronic hepatitis C in industrialized countries, where HCV type 1 accounts for the majority of infections, would be of the order of 50%, that anti-HCV core IgM antibodies are not associated with characteristic features of liver disease, and that their presence before treatment is associated with a failure of interferon alpha therapy to clear the virus.

During human fibrogenesis, myofibroblastlike cells proliferate and are the main source of fibrosis components. We have used cultured myofibroblastlike cells obtained by outgrowth from explants of human liver to study the expression of extracellular matrix (ECM) components and matrix-metalloproteinase-2 (MMP-2) These cells contained types I, III, IV, and V procollagen messenger RNAs (mRNAs). They also expressed mRNAs for laminin B1 chain and for cellular and plasma fibronectin. The corresponding proteins were detected by immunocytochemistry. MMP-2 expression was shown by Northern blot and gelatin zymography. Because transforming growth factor beta 1 (TGF beta 1) is considered an important mediator in liver fibrogenesis, we examined its effect on expression of ECM components by cultural human myofibroblastlike cells. TGF beta 1 increased collagen mRNAs steady-state levels and total collagen secretion in the culture medium. It also increased fibronectin mRNA levels but had no effect on laminin mRNA or MMP-2 expression. In summary, cultured human myofibroblastlike cells express those ECM components that accumulate during hepatic fibrogenesis, indicating the usefulness of this model to study mechanisms of human liver fibrogenesis. In addition to the mitogenic effect of TGF beta 1 on human myofibroblastlike cells, we now demonstrate its stimulation of ECM accumulation in these cells, thus emphasizing the central role of TGF beta 1 and myofibroblastlike cells in the pathophysiology of human hepatic fibrosis.

Interleukin (IL)-17 is a proinflammatory and fibrogenic cytokine mainly produced by T-helper (Th)17 lymphocytes, together with the hepatoprotective and antifibrogenic cytokine, IL-22. Cannabinoid receptor 2 (CB2) is predominantly expressed in immune cells and displays anti-inflammatory and antifibrogenic effects. In the present study, we further investigated the mechanism underlying antifibrogenic properties of CB2 receptor and explored its effect on the profibrogenic properties of IL-17. After bile duct ligation (BDL), the hepatic expression of Th17 markers and IL-17 production were enhanced in CB2(-/-) mice, as compared to wild-type (WT) counterparts, and correlated with increased fibrosis in these animals. In contrast, IL-22-induced expression was similar in both animal groups. Inhibition of Th17 differentiation by digoxin lowered Th17 marker gene expression and IL-17 production and strongly reduced liver fibrosis in CB2(-/-) BDL mice. In vitro, differentiation of CD4(+) naïve T cells into Th17 lymphocytes was decreased by the CB2 agonist, JWH-133, and was associated with reduced Th17 marker messenger RNA expression and IL-17 production, without modification of IL-22 release. The inhibitory effect of JWH-133 on IL-17 production relied on signal transducer and activator of transcription (STAT)5 phosphorylation. Indeed, STAT5 phosphorylation and translocation into the nucleus was enhanced in JWH133-treated Th17 lymphocytes, and the addition of a STAT5 inhibitor reversed the inhibitory effect of the CB2 agonist on IL-17 production, without affecting IL-22 levels. Finally, in vitro studies also demonstrated that CB2 receptor activation in macrophages and hepatic myofibroblasts blunts IL-17-induced proinflammatory gene expression.These data demonstrate that CB2 receptor activation decreases liver fibrosis by selectively reducing IL-17 production by Th17 lymphocytes via a STAT5-dependent pathway, and by blunting the proinflammatory effects of IL-17 on its target cells, while preserving IL-22 production.

International audience; BACKGROUND & AIMS: The aim of this study was to generate an improved prognostic model for predicting recurrence in liver transplant candidates with hepatocellular carcinoma (HCC). METHODS: Predictors of recurrence were tested by a Cox model analysis in a training cohort of 537 patients transplanted for HCC. A prognostic score was developed and validated in a national cohort of 435 patients followed up prospectively. RESULTS: α-Fetoprotein (AFP) independently predicted tumor recurrence and correlated with vascular invasion and differentiation. At a Cox score threshold of 0.7 (area under the receiver operating characteristic curve, 0.701; 95% confidence interval, 0.63-0.76; accuracy, 75.8%), a model combining log(10) AFP, tumor size, and number was highly predictive of tumor recurrence and death. By using a simplified version of the model, with untransformed AFP values, a cut-off value of 2 was identified. In the validation cohort, a score greater than 2 predicted a marked increase in 5-year risk of recurrence (50.6% ± 10.2% vs 8.8% ± 1.7%; P < .001) and decreased survival (47.5% ± 8.1% vs 67.8% ± 3.4%; P = .002) as compared with others. Among patients exceeding Milan criteria, a score of 2 or lower identified a subgroup of patients with AFP levels less than 100 ng/mL with a low 5-year risk of recurrence (14.4% ± 5.3% vs 47.6% ± 11.1%; P = .006). Among patients within Milan criteria, a score greater than 2 identified a subgroup of patients with AFP levels greater than 1000 ng/mL at high risk of recurrence (37.1% ± 8.9% vs 13.3% ± 2.0%; P < .001). Net reclassification improvement showed that predictability of the AFP model was superior to Milan criteria. CONCLUSIONS: Prediction of tumor recurrence is improved significantly by a model that incorporates AFP. We propose the adoption of new selection criteria for HCC transplant candidates, taking into account AFP.

Ethanol undergoes gastric first pass metabolism by alcohol dehydrogenase (ADH). We have shown that cimetidine and famotidine both cause competitive inhibition of human gastric ADH in vitro. However, in a randomized 4-way cross-over study in 12 healthy subjects a 7-day course of treatment with cimetidine (800 mg day-1), ranitidine (300 mg day-1) or famotidine (40 mg day-1), did not modify the pharmacokinetics of ethanol given as a post-prandial 0.3 g kg-1 dose. We conclude that gastric mucosal concentrations of histamine H2-receptor blockers achieved after oral dosing are probably too low to cause significant inhibition of gastric ADH in vivo.

Liver stiffness measurement (LSM) by transient elastography (TE) (FibroScan) is a validated method of quantifying liver fibrosis in non-transplanted patients with hepatitis C virus (HCV). It could be useful in follow-up after liver transplantation (LT). The aim of this study was to assess the diagnostic accuracy of LSM in evaluating liver fibrosis after LT in patients with and without recurrent HCV.Forty-three patients (mean age 57.6 ± 9.9 years), 28 (65.1%) HCV-positive patients and 15 (34.9%) HCV-negative patients underwent gold standard liver biopsy and TE 55.8 ± 4.9 months after transplantation. Liver fibrosis was scored on biopsy specimens according to METAVIR (F0-F4). Accuracy of TE and optimal stiffness cut-off values for fibrosis staging were determined by a receiver-operating characteristics (ROC) curve analysis.Median stiffness values were significantly different for METAVIR score less than 2 (5.8 kPa) vs. METAVIR score greater to equal to 2 (9.6 kPa) (P0.001). The area under the ROC curve was 0.83 for METAVIR score greater to equal to 2 (95%CI: 0.71-0.95). The optimal stiffness cut-off value was 7 kPa for METAVIR scores greater to equal to 2. The results were similar whether the patients had recurrent HCV infection or not.These results indicate that transient elastography accurately identifies LT recipients with significant fibrosis, irrespective of HCV status. It is a promising non-invasive tool to assess graft fibrosis progression after LT in patients with HCV recurrence, as well as for screening of late graft fibrosis of other etiologies. Transient elastography could reduce the use of invasive protocol biopsies.

Background Rapalogs are emerging as promising targeted anticancer drugs. Activation of the PI3K/Akt/mTOR pathway has been observed in 15–50% of hepatocellular carcinomas. Methods In this phase II study, patients with advanced hepatocellular carcinoma and underlying cirrhosis received sirolimus (20 mg/week for 1 month then 30 mg/week). Tumour response was assessed every 8 weeks. The primary endpoint was the objective tumour response rate according to the Response Evaluation Criteria in Solid Tumours criteria. Secondary endpoints included the objective response according to the modified Response Evaluation Criteria in Solid Tumours criteria, safety, and pharmacokinetic parameters. Results Twenty-five patients received sirolimus for a median of 20.6 weeks. Two patients had an objective response (8%, 95CI: 0.98–26.03), including one complete response, and 8 patients had stable disease. There were 2 cases of grade 5 toxicity (infections) and 5 cases of grade 3 toxicity. The main grade 1/2 toxicity was mild transient fatigue (76%). Median time to radiological progression and overall survival were 15.3 weeks (range: 8.2–173.9) and 26.4 weeks (range: 8.2–173.9) respectively. Use of the modified Response Evaluation Criteria in Solid Tumours criteria did not identify any further responders. Conclusion These data suggest that first-line sirolimus shows antitumoural efficacy in advanced hepatocellular carcinoma. Larger trials with Child A patients are needed.

Aliment Pharmacol Ther 2011; 34: 656–663 Summary Background Transient elastography measures liver stiffness, which correlates with the hepatic fibrosis stage and has excellent accuracy for the diagnosis of cirrhosis in patients with chronic hepatitis C. Aim To assess prospectively the kinetics of liver stiffness in treated patients with chronic hepatitis C and compare them with the viral kinetics on treatment and with the final outcome of therapy. Methods 91 patients with chronic hepatitis C with significant fibrosis (>7.0 kPa) at baseline were included. They received therapy with pegylated interferon-α and ribavirin. The kinetics of liver stiffness were characterized during therapy and thereafter by means of Fibroscan, and compared with the virological responses at weeks 4, 12, 24, end of treatment and 12 and 24 weeks after. Results A significant liver stiffness decrease was observed during therapy, which continued after treatment only in patients who achieved a sustained virological response. In this group, the median intra-patient decrease relative to baseline at the end of follow-up was −3.4 kPa, vs−1.8 kPa in the patients who did not achieve an SVR. Similar dynamics were observed in cirrhotic and non-cirrhotic patients. In multivariate analysis, only the SVR was associated with long-term improvement of liver stiffness (odds ratio: 3.10; 95% confidence interval: 1.20–8.02, P = 0.019). Conclusions In patients with advanced fibrosis at the start of therapy, liver stiffness is significantly reduced during treatment, but improvement continues off treatment only in patients who achieve a sustained virological response. Liver stiffness assessment earlier than 6 months after the end of therapy does not appear to be clinically meaningful.

International audience; BACKGROUND & AIMS: In patients with chronic hepatitis C who failed to respond to standard therapy, high-dose pegylated interferon (IFN)-α and/or ribavirin could induce a stronger antiviral response and prevent treatment failure and HCV resistance when combined with direct-acting antivirals. The influence of genetic determinants in this context remains unknown. METHODS: Eighty-three patients infected with HCV genotype 1 who were nonresponsive to standard therapy received pegylated IFN-α2a (360 μg once per week or 180 μg twice per week) with ribavirin (1.0-1.2 or 1.2-1.6 g/d) for up to 72 weeks. Virological responses were assessed at different time points, and the influence of the IL-28B genotype was studied. RESULTS: At weeks 12 and 24, respectively, 47 (56.6%) and 50 (60.2%) patients achieved a ≥2-Log(10) decrease of HCV RNA levels; 8 (9.6%) and 21 (25.3%) patients had undetectable HCV RNA after 12 and 24 weeks of treatment, respectively. Patients with a CT IL-28B genotype responded significantly better and earlier than those with a TT genotype. In multivariate analysis, the IL-28B genotype was an independent predictor of the virological responses at weeks 4, 12, and 24. CONCLUSIONS: High-dose pegylated IFN-α with standard or high doses of ribavirin induces a potent antiviral response in a substantial number of patients who did not respond to standard therapy. The IL-28B genotype is an independent predictor of the antiviral response. High-dose pegylated IFN-α in combination with ribavirin and protease inhibitors appears as an attractive option for future study in this population.

Sickle cell disease (SCD) frequently affects the liver; if acute liver failure (ALF) develops, the only potentially effective therapeutic option is liver transplantation (LT). Only 12 patients for whom LT was performed for SCD-related ALF have been described so far. We report a retrospective series of 6 adult patients with SCD (3 men and 3 women, median age = 40.1 years) who underwent emergency LT. The indication for LT was ALF complicating cirrhosis in 5 patients (hepatitis C/iron overload-induced cirrhosis in 3 and iron overload-induced cirrhosis in 2); one patient had autoimmune hepatitis. The median follow-up was 52.7 months (0.5-123 months). The 1-, 3-, 5-, and 10-year survival rates were 83.3%, 66.7%, 44.4%, and 44.4%, respectively. One patient died of hepatocellular failure precipitated by hyperacute allograft rejection on post-LT day 10. Soon after LT, 2 patients developed seizures; in 1 case, the seizures were a complication of early calcineurin inhibitor-induced leukoencephalopathy. Four long-term survivors benefited from specific management of SCD; specifically, the hemoglobin S fraction was maintained below 30% and the total hemoglobin level was maintained between 8 and 10 g/dL. Two patients had mild vaso-occlusive crises. Three patients experienced a recurrence of hepatitis C virus (HCV) infection; 2 of these patients experienced reversible neurological complications while they were receiving antiviral treatment. Carefully selected patients with SCD may benefit from emergency LT. However, such patients seem to be particularly susceptible to neurological complications after LT. In contrast, severe SCD-related crises do not seem to recur if specific management is provided. Outcomes may be improved if the neurological complications can be minimized; for example, the administration of a calcineurin inhibitor can be delayed, and the management of HCV infection recurrence can be improved.

We assessed the effect of transforming growth factor-beta 1 on the proliferation of human Ito cells. Ito cells in their myofibroblastlike phenotype were grown from explants of human liver and were characterized with electron microscopy and positive immunostaining for desmin and smooth muscle alpha-actin. Transforming growth factor-beta 1 was mitogenic for human Ito cells whatever the culture conditions, although it was, as previously described, inhibitory of growth for rat Ito cells. The mitogenic effect of transforming growth factor-beta 1 was likely due to induction of autocrine platelet-derived growth factor chain secretion by Ito cells themselves because (a) the mitogenic effect of transforming growth factor-beta 1 was blocked by specific platelet-derived growth factor antibodies, (b) transforming growth factor-beta 1 increased platelet-derived growth factor-A chain messenger RNA expression and platelet-derived growth factor-AA secretion by human Ito cells and (c) human Ito cells expressed the alpha-type platelet-derived growth factor-A receptor messenger RNA. Exogenous platelet-derived growth factor-AA was also mitogenic for human Ito cells, mimicking the effect of transforming growth factor-beta 1. Our data suggest that results obtained with rat Ito cells must be extrapolated with caution to human ones. The mitogenic effect of transforming growth factor-beta 1 on human Ito cells probably has pathophysiological relevance because transforming growth factor-beta 1 has been demonstrated in vivo at sites of active liver fibrogenesis.

International audience; The cannabinoid receptor 2 (CB2) plays a pleiotropic role in innate immunity and is a crucial mediator of liver disease. In this study, we investigated the impact of CB2 receptors on the regenerative process associated with liver injury. Following acute hepatitis induced by carbon tetrachloride (CCl(4)), CB2 was induced in the nonparenchymal cell fraction and remained undetectable in hepatocytes. Administration of CCl(4) to CB2(-/-) mice accelerated liver injury, as shown by increased alanine/aspartate aminotransferase levels and hepatocyte apoptosis, and delayed liver regeneration, as reflected by a retarded induction of hepatocyte proliferating cell nuclear antigen expression; proliferating cell nuclear antigen induction was also delayed in CB2(-/-) mice undergoing partial hepatectomy. Conversely, following treatment with the CB2 agonist JWH-133, CCl(4)-treated WT mice displayed reduced liver injury and accelerated liver regeneration. The CCl(4)-treated CB2(-/-) mice showed a decrease in inducible nitric oxide synthase and tumor necrosis factor-alpha expression, and administration of the nitric oxide donor moldomine (SIN-1) to these animals reduced hepatocyte apoptosis, without affecting liver regeneration. Impaired liver regeneration was consecutive to an interleukin-6 (IL-6)-mediated decrease in matrix metalloproteinase 2 (MMP-2) activity. Indeed, CCl(4)-treated CB2(-/-) mice displayed lower levels of hepatic IL-6 messenger RNA and increased MMP-2 activity. Administration of IL-6 to these mice decreased MMP-2 activity and improved liver regeneration, without affecting hepatocyte apoptosis. Accordingly, administration of the MMP inhibitor CTTHWGFTLC to CCl(4)-treated CB2(-/-) mice improved liver regeneration. Finally, in vitro studies demonstrated that incubation of hepatic myofibroblasts with JWH-133 increased tumor necrosis factor-alpha and IL-6 and decreased MMP-2 expressions. CONCLUSION: CB2 receptors reduce liver injury and promote liver regeneration following acute insult, via distinct paracrine mechanisms involving hepatic myofibroblasts. These results suggest that CB2 agonists display potent hepatoprotective properties, in addition to their antifibrogenic effects.

The endocannabinoid system comprises receptors, CB1 and CB2, their endogenous lipidic ligands and machinery dedicated to endocannabinoid synthesis and degradation. An overactive endocannabinoid system appears to contribute to the pathogenesis of several diseases, including liver diseases. With the increasing incidence of non-alcoholic fatty liver disease (NAFLD) in parallel with the obesity epidemic, the development of effective therapies is gaining considerable interest. Several recent experimental lines of evidence identify CB receptors as potential novel therapeutic targets in the management of NAFLD. Endogenous activation of peripheral CB1 receptors is a key mediator of insulin resistance and enhances liver lipogenesis in experimental models of NAFLD. Moreover, we have shown that adipose tissue CB2 receptors are markedly upregulated and promote fat inflammation, thereby contributing to insulin resistance and liver steatosis. Data from our group also indicate that tonic activation of CB1 receptors is responsible for progression of liver fibrosis, whereas CB2 receptors display anti-fibrogenic properties. The clinical relevance of these findings is supported by studies in patients with chronic hepatitis C indicating that daily cannabis use is an independent predictor of both fibrosis and steatosis severity. Moreover, preliminary data derived from clinical trials strongly suggest that selective CB1 antagonism improves insulin resistance and reduces liver fat. Tempering these promises, the first generation of CB1 antagonists raised concern due to an alarming rate of mood disorders and the development program of these molecules was suspended. Current research efforts are therefore focused on developing formulations of CB1 antagonists that do not enter the central nervous system, and preliminary experimental data obtained with such molecules are encouraging.

The severity of chronic hepatitis C (CHC) is modulated by host and environmental factors. Several reports suggest that caffeine intake exerts hepatoprotective effects in patients with chronic liver disease. The aim of this study was to evaluate the impact of caffeine consumption on activity grade and fibrosis stage in patients with CHC.A total of 238 treatment-naïve patients with histologically-proven CHC were included in the study. Demographic, epidemiological, environmental, virological, and metabolic data were collected, including daily consumption of alcohol, cannabis, tobacco, and caffeine during the six months preceding liver biopsy. Daily caffeine consumption was estimated as the sum of mean intakes of caffeinated coffee, tea, and caffeine-containing sodas. Histological activity grade and fibrosis stage were scored according to Metavir. Patients (154 men, 84 women, mean age: 45±11 years) were categorized according to caffeine consumption quartiles: group 1 (225 mg/day, n=59), group 2 (225-407 mg/day, n=57), group 3 (408-678 mg/day, n=62), and group 4 (678 mg/day, n=60).There was a significant inverse relationship between activity grade and daily caffeine consumption: activity gradeA2 was present in 78%, 61%, 52%, and 48% of patients in group 1, 2, 3, and 4, respectively (p0.001). By multivariate analysis, daily caffeine consumption greater than 408 mg/day was associated with a lesser risk of activity gradeA2 (OR=0.32 (0.12-0.85). Caffeine intake showed no relation with fibrosis stage.Caffeine consumption greater than 408 mg/day (3 cups or more) is associated with reduced histological activity in patients with CHC. These findings support potential hepatoprotective properties of caffeine in chronic liver diseases.

In Zajdela hepatoma cells (ZHC) the plasma membrane Ca2+ pump displayed no sensitivity to glucagon (19-29) (mini-glucagon), whereas in hepatocyte this metabolite of glucagon evoked a biphasic regulation of the Ca2+ pump system via a cholera toxin-sensitive G protein. Analysis of G protein subunits in ZHC membranes indicated the presence of cholera toxin-sensitive Gs alpha and G beta gamma proteins, whose functionality was manifested by GTP and NaF stimulation of adenylylcyclase activity, and pertussis toxin-catalyzed ADP-ribosylation of Gi alpha, respectively. However, immunoblotting experiments suggested a lower content in beta gamma subunits in ZHC as compared with hepatocyte plasma membranes. Complementation of ZHC or hepatocyte plasma membranes with purified beta gamma subunits from transducin (T beta gamma) caused inhibition of the basal activity of the Ca2+ pump at 10 and 300 ng/ml, respectively, and revealed (in ZHC) or increased (in hepatocytes) sensitivity of the system to mini-glucagon. After cholera toxin treatment of ZHC, T beta gamma no longer reconstituted the response of the Ca2+ pump to mini-glucagon, suggesting that the mechanism of beta gamma action is dependent on an association with the alpha subunit of a cholera toxin-sensitive G protein. It is concluded that G beta gamma subunits control both the basal activity of the plasma membrane Ca2+ pump and its inhibition by mini-glucagon.

Background/Purpose: Liver transplantation (LT) is the best theoretical treatment of hepatocellular carcinoma (HCC) fulfilling the Milan criteria (TNM stages 1-2). However, LT is limited by organ availability and tumor progression on the waiting list. Liver resection (LR) may represent an alternative in these patients. The aim of this study is to report the results of LR in transplantable patients. Patients: From 1990 to 2007, 274 patients underwent liver resection for HCC. Sixty-seven (24%) met the Milan criteria on pathologic study of the specimen. Ten were TNM stage 1 and 57 stage 2 and all had chronic liver disease. There were 56 men and 11 women with a mean age of 63. LR included 12 major hepatectomies, 14 bisegmentectomies, 14 segmentectomies, and 27 nonanatomic resections. Thirty-seven resections were performed through a laparoscopic approach and there were only 8 open resections since 1998. Results: Three patients died postoperatively (4.5%), none after laparoscopic resection. Morbidity rate was 34%. After a mean follow-up of 4.8 years, 36 patients (54%) developed intrahepatic tumor recurrence. Twenty-eight (77%) were again transplantable of which 16 (44%) were transplanted. Two additional patients underwent pre-emptive LT (ie before recurrence). When considering 44 patients

Despite recent advances in the understanding of mechanisms underlying the pathogenesis of liver diseases, therapeutic agents are still needed in several instances such as nonalcoholic fatty liver disease, alcoholic liver disease or fibrogenesis associated with chronic liver injury. Over the past decades, cannabinoid receptors have emerged as critical mediators of acute and chronic liver injury, and pharmacological modulation of these receptors has demonstrated efficacy in preclinical models of nonalcoholic and alcoholic fatty liver, fibrosis, liver ischemia reperfusion and of complications of cirrhosis, including cirrhotic portal hypertension, cirrhotic cardiomyopathy and hepatic encephalopathy. Moreover, CB(1) antagonists have entered clinical trials for the management of nonalcoholic steatohepatitis. This review will depict the pleiotropic functions of cannabinoid receptors in liver disease and highlight potential therapeutic applications, some of which may be available in the near future.

International audience; BACKGROUND: Obesity-associated inflammation is of critical importance in the development of insulin resistance and non-alcoholic fatty liver disease. Since the cannabinoid receptor CB2 regulates innate immunity, the aim of the present study was to investigate its role in obesity-induced inflammation, insulin resistance and fatty liver. METHODOLOGY: Murine obesity models included genetically leptin-deficient ob/ob mice and wild type (WT) mice fed a high fat diet (HFD), that were compared to their lean counterparts. Animals were treated with pharmacological modulators of CB2 receptors. Experiments were also performed in mice knock-out for CB2 receptors (Cnr2 -/-). PRINCIPAL FINDINGS: In both HFD-fed WT mice and ob/ob mice, Cnr2 expression underwent a marked induction in the stromal vascular fraction of epididymal adipose tissue that correlated with increased fat inflammation. Treatment with the CB2 agonist JWH-133 potentiated adipose tissue inflammation in HFD-fed WT mice. Moreover, cultured fat pads isolated from ob/ob mice displayed increased Tnf and Ccl2 expression upon exposure to JWH-133. In keeping, genetic or pharmacological inactivation of CB2 receptors decreased adipose tissue macrophage infiltration associated with obesity, and reduced inductions of Tnf and Ccl2 expressions. In the liver of obese mice, Cnr2 mRNA was only weakly induced, and CB2 receptors moderately contributed to liver inflammation. HFD-induced insulin resistance increased in response to JWH-133 and reduced in Cnr2 -/- mice. Finally, HFD-induced hepatic steatosis was enhanced in WT mice treated with JWH-133 and blunted in Cnr2 -/- mice. CONCLUSION/SIGNIFICANCE: These data unravel a previously unrecognized contribution of CB2 receptors to obesity-associated inflammation, insulin resistance and non-alcoholic fatty liver disease, and suggest that CB2 receptor antagonists may open a new therapeutic approach for the management of obesity-associated metabolic disorders.

International audience; Prevalence of non-alcoholic steatohepatitis (NASH) rises steadily in Western countries with the obesity epidemic. NASH is associated with activation of liver fibrogenesis and predisposes to cirrhosis and associated morbi-mortality. The cannabinoid system is increasingly emerging as a crucial mediator of acute and chronic liver injury. Recent experimental and clinical data indicate that peripheral activation of cannabinoid CB1 receptors promotes insulin resistance and liver steatogenesis, two key steps in the pathogenesis of non-alcoholic fatty liver disease. Moreover, CB1 receptors enhance progression of liver fibrogenesis. These findings provide a strong rationale for the use of CB1 antagonists in the management of NASH.

Cannabinoid receptors (CB1 and CB2) and their endogenous ligands (endocannabinoids) have recently emerged as novel mediators of liver diseases. Endogenous activation of CB1 receptors promotes nonalcoholic fatty liver disease (NAFLD) and progression of liver fibrosis associated with chronic liver injury; in addition, CB1 receptors contribute to the pathogenesis of portal hypertension and cirrhotic cardiomyopathy. CB2 receptor-dependent effects are also increasingly characterized, including antifibrogenic effects and regulation of liver inflammation during ischemia-reperfusion and NAFLD. It is likely that the next few years will allow us to delineate whether molecules targeting CB1 and CB2 receptors are useful therapeutic agents for the treatment of chronic liver diseases.

Sphingosine 1-phosphate (S1P) is a bioactive sphingolipid produced by sphingosine kinase (SphK1 and 2). We previously showed that S1P receptors (S1P1, S1P2, and S1P3) are expressed in hepatic myofibroblasts (hMF), a population of cells that triggers matrix remodeling during liver injury. Here we investigated the function of these receptors in the wound healing response to acute liver injury elicited by carbon tetrachloride, a process that associates hepatocyte proliferation and matrix remodeling. Acute liver injury was associated with the induction of S1P2, S1P3, SphK1, and SphK2 mRNAs and increased SphK activity, with no change in S1P1 expression. Necrosis, inflammation, and hepatocyte regeneration were similar in S1P2(-/-) and wild-type (WT) mice. However, compared with WT mice, S1P2(-/-) mice displayed reduced accumulation of hMF, as shown by lower induction of smooth muscle alpha-actin mRNA and lower induction of TIMP-1, TGF-beta1, and PDGF-BB mRNAs, overall reflecting reduced activation of remodeling in response to liver injury. The wound healing response was similar in S1P3(-/-) and WT mice. In vitro, S1P enhanced proliferation of cultured WT hMF, and PDGF-BB further enhanced the mitogenic effect of S1P. In keeping with these findings, PDGF-BB up-regulated S1P2 and SphK1 mRNAs, increased SphK activity, and S1P2 induced PDGF-BB mRNA. These effects were blunted in S1P2(-/-) cells, and S1P2(-/-) hMF exhibited reduced mitogenic and comitogenic responses to S1P. These results unravel a novel major role of S1P2 in the wound healing response to acute liver injury by a mechanism involving enhanced proliferation of hMF.--Serriere-Lanneau, V., Teixeira-Clerc, F., Li, L., Schippers, M., de Wries, W., Julien, B., Tran-Van-Nhieu, J., Manin, S., Poelstra, K., Chun, J., Carpentier, S., Levade, T., Mallat, A., Lotersztajn, S. The sphingosine 1-phosphate receptor S1P2 triggers hepatic wound healing.

Chronic liver injury exposes the patient to liver fibrosis and its end stage, cirrhosis, is a major public health problem worldwide. In western countries, prevailing causes of cirrhosis include chronic alcohol consumption, hepatitis C virus infection and non-alcoholic steatohepatitis. Current treatment of hepatic fibrosis is limited to withdrawal of the noxious agent. Nevertheless, suppression of the cause of hepatic injury is not always feasible and numerous efforts are directed at the development of liver-specific antifibrotic therapies. Along these lines, the authors recently demonstrated that the endocannabinoid system shows promise as a novel target for antifibrotic therapy during chronic liver injury. Indeed, cannabinoid receptors CB1 and CB2 promote dual pro- and antifibrogenic effects, respectively. Therefore, endocannabinoid-based therapies, combining CB2 agonists and CB1 antagonists may open novel therapeutic perspectives for the treatment of chronic liver diseases.

The antifungal drug terbinafine has infrequently been incriminated in the occurrence of acute liver injury. We report a case of prolonged cholestasis that occurred in a 75-year-old woman, following terbinafine administration. Jaundice followed by pruritus appeared after four weeks of therapy and was associated with mixed hepatocellular and cholestatic liver tests abnormalities. Following drug withdrawal, serum bilirubin returned to normal values within three months, but anicteric cholestasis persisted for over six months. A liver biopsy performed after six months showed centrilobular cholestasis, discrete portal fibrosis, and a reduction in the number of interlobular biliary ducts. Terbinafine should be added to the list of drugs that can cause reduction in interlobular bile ducts.

Hepatic fibrosis, the common response associated with chronic liver diseases, ultimately leads to cirrhosis, a major public health problem worldwide. We recently showed that activation of hepatic cannabinoid CB2 receptors limits progression of experimental liver fibrosis. We also found that during the course of chronic hepatitis C, daily cannabis use is an independent predictor of fibrosis progression. Overall, these results suggest that endocannabinoids may drive both CB2-mediated antifibrogenic effects and CB2-independent profibrogenic effects. Here we investigated whether activation of cannabinoid CB1 receptors (encoded by Cnr1) promotes progression of fibrosis. CB1 receptors were highly induced in human cirrhotic samples and in liver fibrogenic cells. Treatment with the CB1 receptor antagonist SR141716A decreased the wound-healing response to acute liver injury and inhibited progression of fibrosis in three models of chronic liver injury. We saw similar changes in Cnr1-/- mice as compared to wild-type mice. Genetic or pharmacological inactivation of CB1 receptors decreased fibrogenesis by lowering hepatic transforming growth factor (TGF)-beta1 and reducing accumulation of fibrogenic cells in the liver after apoptosis and growth inhibition of hepatic myofibroblasts. In conclusion, our study shows that CB1 receptor antagonists hold promise for the treatment of liver fibrosis.

▪ Abstract Liver fibrosis is the common response to chronic liver injury, ultimately leading to cirrhosis and its complications, portal hypertension, liver failure, and hepatocellular carcinoma. Efficient and well-tolerated antifibrotic drugs are currently lacking, and current treatment of hepatic fibrosis is limited to withdrawal of the noxious agent. Efforts over the past decade have mainly focused on fibrogenic cells generating the scarring response, although promising data on inhibition of parenchymal injury and/or reduction of liver inflammation have also been obtained. A large number of approaches have been validated in culture studies and in animal models, and several clinical trials are underway or anticipated for a growing number of molecules. This review highlights recent advances in the molecular mechanisms of liver fibrosis and discusses mechanistically based strategies that have recently emerged.

Background/Aims Hepatic myofibroblasts are central in liver fibrogenesis associated with chronic liver diseases. We previously showed that heme-oxygenase-1 (HO-1) displays antifibrogenic properties in human hepatic myofibroblasts. Here, we further investigated the mechanisms regulating HO-1 expression. Methods Expression of HO-1 was assayed in cultured human hepatic myofibroblasts by Northern and Western blot. Functional studies were also performed in cultured human hepatic myofibroblasts. Results 15-Deoxy-Δ 12,14 -prostaglandin J2 (15-d-PGJ2) elicited inhibition of proliferation and of α1(I) collagen mRNA expression. These effects were reproduced by the glutathione depletor diethyl maleate and blunted by the glutathione precursor N -acetyl cysteine, indicating the involvement of oxidative stress. Two consecutive events mediated inhibition of proliferation and of α1(I) collagen mRNA expression by 15-d-PGJ2: (i) mild oxidative stress characterized by a transient GSH decrease and (ii) activation of p38 MAPK, resulting in increased HO-1 mRNA stability. Conclusions Our results provide new insights into the regulatory mechanisms governing HO-1 expression in human hepatic myofibroblasts and identify mild oxidative stress and p38 MAPK as two consecutive early signals promoting HO-1 induction that are crucial for its antifibrogenic properties, namely inhibition of growth and extracellular matrix gene expression.