Overexpression of endoglin modulates TGF-ß1-signalling pathways in a novel immortalized mouse hepatic stellate cell line.

Hepatic stellate cells (HSCs) play a major role in the pathogenesis of liver fibrosis. Working on primary HSCs requires difficult isolation procedures; therefore we have generated and here characterize a mouse hepatic stellate cell line expressing GFP under control of the collagen 1(I) promoter/enhancer. These cells are responsive to pro-fibrogenic stimuIi, such as PDGF or TGF-ß1, and are able to activate intracellular signalling pathways including Smads and MAP kinases. Nevertheless, due to the basal level of activation, TGF-ß1 did not significantly induce GFP expression contrasting the TGF-ß1 regulated endogenous collagen I expression. We could demonstrate that the accessory TGF-ß-receptor endoglin, which is endogenously expressed at very low levels, has a differential effect on signalling of these cells when transiently overexpressed. In the presence of endoglin activation of Smad1/5/8 was drastically enhanced. Moreover, the phosphorylation of ERK1/2 was increased, and the expression of vimentin, α-smooth muscle actin and connective tissue growth factor was upregulated. Endoglin induced a slight increase in expression of the inhibitor of differentiation-2 while the amount of endogenous collagen type I was reduced. Therefore, this profibrogenic cell line with hepatic stellate cell origin is not only a promising novel experimental tool, which can be used in vivo for cell tracing experiments. Furthermore it allows investigating the impact of various regulatory proteins (e.g. endoglin) on profibrogenic signal transduction, differentiation and hepatic stellate cell biology.

Evolution of adefovir-resistant HBV polymerase gene variants after switching to tenofovir disoproxil fumarate monotherapy.

BACKGROUND: Tenofovir disoproxil fumarate (TDF), an acyclic nucleotide analogue was shown to be effective in many HBV-infected patients with resistance to adefovir dipivoxil (ADV). This observation is intriguing because in vitro studies show that HBV mutations selected by ADV confer cross-resistance to TDF. To assess the clinical relevance of this cross-resistance, we studied the evolution of HBV polymerase gene variants in patients with genotypic resistance against ADV (rtN236T and/or rtA181V/T) during TDF treatment. METHODS: In 10 HBV-monoinfected patients (9 male, mean age 47 ±11 [range 27-67] years, 6 hepatitis B e antigen-positive) with virological breakthrough during ADV treatment associated with the mutations rtN236T and/or rtA181T/V, HBV polymerase gene variants were studied during up to 24 months of consecutive monotherapy with TDF by population sequencing, line probe assay and clonal analysis. RESULTS: In all patients, switching to TDF resulted in a continuous reduction of HBV DNA from a median of 7.6 (4.6-9.4) log(10) copies/ml to 3.3 (2-5) log(10) copies/ml, remaining in 7 patients >400 copies/ml at 12 months. ADV-resistance mutations remained detectable throughout the whole observation period in most patients. Apart from an M204Q mutation in one sample, no new HBV polymerase gene mutations were found. In two patients with low level viraemia after 72 weeks of TDF, adding lamivudine led to a complete response within a few weeks. CONCLUSIONS: ADV-resistant HBV variants may further become selected during TDF treatment, however they cause only a mild decrease in TDF susceptibility.

BASIC--a bile acid-sensitive ion channel highly expressed in bile ducts.

Brain liver intestine Na+ channel (BLINaC) is an ion channel of the DEG/ENaC gene family of unknown function. BLINaC from rats (rBLINaC) and humans (INaC) is inactive at rest, and its mode of activation has remained unclear. Here, we show that the BLINaC protein localizes to cholangiocytes, epithelial cells that line bile ducts. Moreover, we provide evidence that rBLINaC and INaC are robustly activated by bile acids, in particular chenodeoxycholic acid and hyodeoxycholic acid (EC50=2.1±0.05 mM). Thus, BLINaC appears to be an epithelial cation channel of bile ducts sensitive to physiological concentrations of bile acids. BLINaC is related to acid-sensing ion channels (ASICs) and to the epithelial Na+ channel (ENaC) and shares ligand activation with ASICs and epithelial localization with ENaC. Therefore, based on the close homology of BLINaC to ASICs and its activation by bile acids, we propose to rename BLINaC bile acid-sensitive ion channel (BASIC).

The chemokine receptor CXCR3 limits injury after acute toxic liver damage.

Although acute liver failure is a rare disease, its presence is associated with high morbidity and mortality in affected patients. While a contribution of the immune system to the outcome of toxic liver failure is anticipated, functionally relevant immune cell receptors for liver cell damage need to be better defined. We here investigate the relevance of the chemokine receptor CXCR3, which is important for hepatic immune cell infiltration, in a model of experimental acute liver failure. Liver injury was induced by a single intraperitoneal injection of carbon tetrachloride (CCl(4)) in CXCR3(-/-), CCR1(-/-), CCR5(-/-) and wild-type mice. In this model, CXCR3(-/-) mice displayed augmented liver damage compared with all other mouse strains as assessed by liver histology and serum transaminases 24 and 72 h after injury. Phenotypically, CXCR3(-/-) mice had significantly reduced intrahepatic NK and NKT cells after injury at all investigated time points (all P<0.05), but strongly elevated expression levels of IL1-ß, TNF-α and IFN-γ. In line with a functional role of innate immune cells, wild-type mice depleted for NK cells with an anti-ASIALO GM1 antibody before liver injury also displayed increased liver injury after CCl(4) challenge. CXCR3(-/-) and NK cell-depleted mice show reduced apoptotic liver cells (TUNEL assay), but more necrotic hepatocytes. Functionally, the augmented liver cell necrosis in CXCR3(-/-) and NK cell-depleted mice was associated with increased expression of high mobility group 1 (HMGB1) protein and a consecutive enhanced infiltration of neutrophils into the liver. In conclusion, the results demonstrate a primarily unexpected beneficial role of CXCR3 in acute toxic liver injury. These findings should be taken into account when planning trials with CXCR3 antagonists.

Hepatocyte growth factor/c-Met signalling is important for the selection of transplanted hepatocytes.

BACKGROUND: At present hepatocyte transplantation is a promising option for cellular therapy of end-stage liver diseases. However, the underlying molecular mechanisms need to be better defined in order to translate this technique into clinical use. This study investigated the cursiv relevance of hepatocyte growth factor (HGF)/c-Met signalling for hepatocyte repopulation after transplantion. METHODS: Wild-type mice (c-Met(loxP/loxP)) and hepatocyte-specific conditional c-Met (HGF receptor) knockout (c-Met(Δhepa)) mice were used as donors and recipients for hepatocyte transplantation. RESULTS: Transplantation experiments revealed two major findings. First it was demonstrated that c-Met is indispensable in donor cells, as c-Met(Δhepa) cells did not repopulate recipient livers after transplantation. Second, genetic deletion of c-Met in recipient hepatocytes resulted in enhanced expansion of unmodified donor cells in host livers (up to 250-fold after 12 weeks). The relevant mechanisms for this observation in c-Met(Δhepa) host hepatocytes could be defined. c-Met(Δhepa) hepatocytes showed enhanced apoptosis, reduced cellular proliferation and a lack of AKT-kinase and STAT3 activation. In addition, tissue remodelling was changed in c-Met(Δhepa) recipient livers. Therefore, the lack of pro-proliferative transcription factors, increased apoptosis and changes in matrix-remodelling inhibit host cell proliferation in c-Met(Δhepa) recipient livers and thus favour repopulation of transplanted hepatocytes. Therapeutically liver repopulation could be increased through adenoviral expression of NK-4--an inhibitor of HGF signalling--in host hepatocytes. CONCLUSION: HGF/c-Met plays a crucial role in host and donor cells of the liver for the cursiv selection of transplanted hepatocytes. Modulating HGF-dependent signalling seems a promising therapeutic option to favour expansion of transplanted hepatocytes.

Adaptive immunity suppresses formation and progression of diethylnitrosamine-induced liver cancer.

BACKGROUND: Hepatocellular carcinoma (HCC) is a typical inflammation-associated cancer, but may also provoke antitumour immune responses whose significance and underlying mechanisms are incompletely understood. OBJECTIVE: To characterise immune responses in the diethylnitrosamine (DEN)-liver cancer mouse model. DESIGN: Tumour development and immune cell functions upon DEN treatment were compared between C57BL/6 wild-type (WT), chemokine scavenging receptor D6-deficient, B cell- (Igh6), CD4 T cell- (MHC-II) and T-/B cell-deficient (Rag1) mice. Relevance for human HCC was tested by comparing gene array results from 139 HCC tissues. RESULTS: The induction of premalignant lesions after 24 weeks and of HCC-like tumours after 42 weeks by DEN in mice was accompanied by significant leucocyte infiltration in the liver and upregulation of distinct intrahepatic chemokines (CCL2, CCL5, CXCL9). Macrophages and CD8 (cytotoxic) T cells were most prominently enriched in tumour-bearing livers, similar to samples from human HCC. Myeloid-derived suppressor cells (MDSC) increased in extrahepatic compartments of DEN-treated mice (bone marrow, spleen). The contribution of immune cell subsets for DEN-induced hepatocarcinogenesis was functionally dissected. In D6(-/-) mice, which lack the chemokine scavenging receptor D6, hepatic macrophage infiltration was significantly increased, but tumour formation and progression did not differ from that of WT mice. In contrast, progression of hepatic tumours (numbers, diameters, tumour load) was strikingly enhanced in T-/B cell-deficient Rag1(-/-) mice upon DEN treatment. When mice deficient for B cells (Igh6(-/-), µMT) or major histocompatibility complex II were used, the data indicated that T cells prevent initial tumour formation, while B cells critically limit growth of established tumours. Accordingly, in tumour-bearing mice antibody production against liver-related model antigen was enhanced, indicating tumour-associated B cell activation. In agreement, T and B cell pathways were differentially regulated in gene array analyses from 139 human HCC tissues and significantly associated with patients' survival. CONCLUSIONS: Distinct axes of the adaptive immune system, which are also prognostic in human HCC, actively suppress DEN-induced hepatocarcinogenesis by controlling tumour formation and progression.

Soluble urokinase plasminogen activator receptor is associated with progressive liver fibrosis in hepatitis C infection.

BACKGROUND: Progressive liver fibrosis is the main predictor of disease outcome in chronic hepatitis C viral (HCV) infection. Although the importance of the coagulation cascade has been suggested in liver fibrogenesis, the role of the fibrinolytic pathway is yet unclear. GOAL: We evaluated the association of serum levels of the fibrinolysis-associated soluble urokinase plasminogen activator receptor (suPAR) with the severity of liver fibrosis in HCV infection. STUDY: suPAR serum levels were assessed in 146 chronically HCV-infected patients of 2 independent cohorts (64 subjects in the screening cohort, 82 in the validation cohort) by enzyme-linked immunosorbent assay and correlated with biopsy-proven histologic stage of liver fibrosis and noninvasive liver fibrosis markers (aspartate transaminase to platelets ratio index score, transient elastography). RESULTS: suPAR serum levels were strongly associated with the histologic stage of liver fibrosis in both cohorts (P<0.0001). Although mean suPAR levels in patients with F1 and F2 fibrosis were not different from healthy control subjects, they were significantly increased at higher stages of liver fibrosis (F3 and F4, P<0.0001). suPAR values had a high diagnostic specificity and sensitivity to differentiate mild/moderate fibrosis (F1/F2) from severe fibrosis (F3/F4) with an area under curve of 0.774 (P=0.0001) and for the differentiation of noncirrhosis from cirrhosis (F1/F2/F3 vs. F4, area under curve 0.791, P=0.0001). SuPAR serum levels were also strongly correlated to the noninvasive fibrosis markers aspartate transaminase to platelets ratio index score (r=0.52) and transient elastography (r=0.44, both P<0.0001). CONCLUSIONS: Serum suPAR levels were robust markers of liver fibrosis in 2 cohorts with a comparable diagnostic accuracy for prediction of severe liver fibrosis as established noninvasive marker.

A 7-gene signature of the recipient predicts the progression of fibrosis after liver transplantation for hepatitis C virus infection.

Fibrosis recurrence after liver transplantation (LT) for hepatitis C virus (HCV) is a universal event and strongly determines a patient's prognosis. The recipient risk factors for fibrosis recurrence are still poorly defined. Here we assess a genetic risk score as a predictor of fibrosis after LT. The cirrhosis risk score (CRS), which comprises allele variants in 7 genes (adaptor-related protein complex 3 S2, aquaporin 2, antizyme inhibitor 1, degenerative spermatocyte homolog 1 lipid desaturase, syntaxin binding protein 5-like, toll-like receptor 4, and transient receptor potential cation channel M5), was calculated for 137 patients who underwent LT for HCV infection and experienced HCV reinfection of the graft. The patients were stratified into 3 CRS categories: <0.5, 0.5 to 0.7, and >0.7. All patients underwent protocol biopsy after LT (median follow-up = 5 years), and liver fibrosis was assessed according to the Desmet and Scheuer score. The data were analyzed with univariate and multivariate analyses. The results showed that the highest CRS category was strongly associated with the presence of F2 or F3 fibrosis in protocol biopsy samples 1, 3, and 5 years after LT (P = 0.006, P = 0.001, and P = 0.02, respectively). Overall, 75.0% of the patients with a CRS > 0.7 developed at least F2 fibrosis, whereas 51.5% developed F3 fibrosis during follow-up. The predictive value of the CRS for fibrosis progression was independent of known clinical risk factors, including the age of the donor, the sex of the recipient, and the occurrence of acute rejection. A Kaplan-Meier analysis confirmed the prognostic value of the CRS with respect to the recurrence of severe liver fibrosis in HCV-infected patients after LT (log rank = 6.23, P = 0.03). In conclusion, the genetic signature of the recipient predicts the likelihood of severe liver fibrosis in the graft after HCV recurrence. The CRS might help with early clinical decision making (eg, the selection of patients for antiviral therapy after LT).

Serum chemokine receptor CXCR3 ligands are associated with progression, organ dysfunction and complications of chronic liver diseases.

BACKGROUND: Chemokines are chemotactic mediators that are implicated in liver diseases. In viral hepatitis and primary biliary cirrhosis, a predominant chemokine receptor expressed in the liver is CXCR3, suggesting that its specific ligands are important in the progression of chronic liver diseases across different aetiologies. METHODOLOGY/PRINCIPAL FINDINGS: We analysed the serum concentrations of the CXCR3 ligands, CXCL9 (monokine induced by interferon-γ), CXCL10 (interferon-γ-inducible protein 10) and CXCL11 (interferon-inducible T cell α chemo-attractant) in healthy controls (n=53), subjects with histologically determined liver fibrosis (n=109) and patients with different stages of cirrhosis (n=153) of various disease aetiologies. Chemokine concentrations were determined by cytometric bead assay or ELISA respectively. Serum concentrations of all three chemokines were significantly increased in patients with chronic liver diseases compared with healthy controls (P<0.001). In the biopsied fibrosis cohort, CXCL9 and CXCL10 were positively associated with the severity of liver fibrosis (histology and serum markers), while CXCL11 was not. In cirrhotic patients, CXCL9 was increased in early Child-Pugh stages, while CXCL11 was elevated only in Child B and C patients and CXCL10 across all stages. Notably, CXCR3 chemokines were also associated with the development of clinical complications of cirrhosis, especially portal hypertension. All chemokines significantly correlated with serum levels of the hepatoprotective cytokines interleukin (IL)-6 and IL-10, suggesting their involvement in a counter-regulatory response during the progression of liver disease, shedding new light on their involvement in the pathophysiology of chronic liver diseases. CONCLUSIONS: CXCR3 chemokines are differentially expressed during chronic liver diseases across different disease stages and aetiologies. Their association with portal hypertension and hepatoprotective cytokines implies biological functions beyond immune cell recruitment, thereby provoking new diagnostic and therapeutic concepts.

Severe gastric variceal haemorrhage due to splenic artery thrombosis and consecutive arterial bypass.

BACKGROUND: Upper gastrointestinal haemorrhage is mainly caused by ulcers. Gastric varicosis due to portal hypertension can also be held responsible for upper gastrointestinal bleeding. Portal hypertension causes the development of a collateral circulation from the portal to the caval venous system resulting in development of oesophageal and gastric fundus varices. Those may also be held responsible for upper gastrointestinal haemorrhage. CASE PRESENTATION: In this study, we describe the case of a 69-year-old male with recurrent severe upper gastrointestinal bleeding caused by arterial submucosal collaterals due to idiopathic splenic artery thrombosis. The diagnosis was secured using endoscopic duplex ultrasound and angiography. The patient was successfully treated with a laparoscopic splenectomy and complete dissection of the short gastric arteries, resulting in the collapse of the submucosal arteries in the gastric wall. Follow-up gastroscopy was performed on the 12th postoperative week and showed no signs of bleeding and a significant reduction in the arterial blood flow within the gastric wall. Subsequent follow-up after 6 months also showed no further gastrointestinal bleeding as well as subjective good quality of life for the patient. CONCLUSION: Submucosal arterial collaterals must be excluded by endosonography via endoscopy in case of recurrent upper gastrointestinal bleeding. Laparoscopic splenectomy provides adequate treatment in preventing any recurrent bleeding, if gastric arterial collaterals are caused by splenic artery thrombosis.

Assessment of inflammatory and fibrotic stenoses in patients with Crohn's disease using contrast-enhanced ultrasound and computerized algorithm: a pilot study.

PURPOSE: The development of stenosis is a typical complication of Crohn's disease and represents a serious diagnostic and therapeutic challenge. The aim of the present study was to define objective quantitative measures of stricture characteristics (fibrostenotic/cicartricial vs. inflammatory) using contrast-enhanced ultrasound (CEUS) in patients with stenotic Crohn's disease. MATERIALS AND METHODS: During a period of 18 months, 18 consecutive patients with Crohn's disease and manifestation of a localized significant small bowel stenosis were prospectively recruited. Standardized ultrasound (US) examination, color-coded duplex sonography and CEUS using SonoVue® were performed. Quantitative measurements of bowel wall vascularity were determined using computerized algorithms (Bracco QONTRAST software). The quality of stenosis (fibrostenotic vs. inflammatory) was classified in a 4-point scale, and the diagnostic/prognostic power of the US and clinical tests upon initial presentation were compared. RESULTS: We established a novel standardized CEUS procedure using computerized algorithms to quantitatively examine stenoses in Crohn's disease. An inflammatory origin of stenosis correlated significantly with a high Crohn's Disease Activity Index (CDAI) (p < 0.01), the length of stenosis (p < 0.01) as well as the Limberg score (p < 0.01). There was no correlation between the type of stenosis and quantitative results of CEUS. CONCLUSION: Although bowel wall vascularity can be quantitatively assessed in stenotic areas by CEUS, this analysis does not improve the diagnostic power for the objective determination of the quality of stenosis at a single measurement. Semiquantitative analysis of bowel wall vascularity, length of stenosis, and CDAI may help to discriminate the origin of small bowel stenosis in Crohn's disease.

Serum chemokine CXC ligand 10 (CXCL10) predicts fibrosis progression after liver transplantation for hepatitis C infection.

UNLABELLED: The recurrence of liver fibrosis after liver transplantation (LT) for hepatitis C virus (HCV) infection is responsible for graft loss and patient mortality. Although the contribution of the immune system to fibrosis recurrence is anticipated, systematic studies evaluating immune parameters as predictive markers of allograft fibrosis are lacking. The infiltration of immune cells into the graft is governed by chemokines. Here we assessed the predictive value of serum levels of chemokines [chemokine (C-X-C motif) ligand 9 (CXCL9), CXCL10, CXCL11, and chemokine (C-C motif) ligand 2 (CCL2)] with respect to fibrosis recurrence after LT in 90 HCV-infected organ recipients. Chemokines were determined within the first and third years after LT and were correlated with histological fibrosis progression in protocol biopsy samples at 1, 3, 5, and 7 years (median follow-up = 3 years). The association of chemokines with fibrosis progression was assessed by univariate and multivariate analyses and by Cox regression analysis. The results for the analyzed chemokines showed that CXCL10 levels in the first year after LT were strongly associated with early fibrosis recurrence (P = 0.005) independently of risk confounders (including the donor age, HCV viral load, HCV genotype, acute rejection, and inflammatory activity). As assessed by Cox regression analysis, a CXCL10 serum level ≤ 140 pg/mL was significantly predictive of the absence of F2 fibrosis (P = 0.001), whereas a level ≤ 220 pg/mL early after LT predicted the absence of F3 fibrosis during follow-up (P = 0.035). CONCLUSION: CXCL10 is an independent biomarker of the recurrence of significant fibrosis after LT for HCV infection. These results might guide patients' care after transplantation and help us to select optimal candidates for antiviral therapy post-LT.

The fractalkine receptor CX3CR1 protects against liver fibrosis by controlling differentiation and survival of infiltrating hepatic monocytes.

UNLABELLED: Chemokines modulate inflammatory responses that are prerequisites for organ fibrosis upon liver injury. Monocyte-derived hepatic macrophages are critical for the development, maintenance, and resolution of hepatic fibrosis. The specific role of monocyte-associated chemokine (C-X3-C motif) receptor 1 (CX3CR1) and its cognate ligand fractalkine [chemokine (C-X3-C motif) ligand 1)] in liver inflammation and fibrosis is currently unknown. We examined 169 patients with chronic liver diseases and 84 healthy controls; we found that CX3CL1 is significantly up-regulated in the circulation upon disease progression, whereas CX3CR1 is down-regulated intrahepatically in patients with advanced liver fibrosis or cirrhosis. To analyze the functional relevance of this pathway, two models of experimental liver fibrosis were applied to wild-type (WT) and CX3CR1-deficient mice. Fractalkine expression was induced upon liver injury in mice, primarily in hepatocytes and hepatic stellate cells. CX3CR1(-/-) animals developed greater hepatic fibrosis than WT animals with carbon tetrachloride-induced and bile duct ligation-induced fibrosis. CX3CR1(-/-) mice displayed significantly increased numbers of monocyte-derived macrophages within the injured liver. Chimeric animals that underwent bone marrow transplantation revealed that CX3CR1 restricts hepatic fibrosis progression and monocyte accumulation through mechanisms exerted by infiltrating immune cells. In the absence of CX3CR1, intrahepatic monocytes develop preferentially into proinflammatory tumor necrosis factor-producing and inducible nitric oxide synthase-producing macrophages. CX3CR1 represents an essential survival signal for hepatic monocyte-derived macrophages by activating antiapoptotic bcl2 expression. Monocytes/macrophages lacking CX3CR1 undergo increased cell death after liver injury, which then perpetuates inflammation, promotes prolonged inflammatory monocyte infiltration into the liver, and results in enhanced liver fibrosis. CONCLUSION: CX3CR1 limits liver fibrosis in vivo by controlling the differentiation and survival of intrahepatic monocytes. The opposing regulation of CX3CR1 and fractalkine in patients suggests that pharmacological augmentation of this pathway may represent a possible therapeutic antifibrotic strategy.

Antagonism of the chemokine Ccl5 ameliorates experimental liver fibrosis in mice.

Activation of hepatic stellate cells in response to chronic inflammation represents a crucial step in the development of liver fibrosis. However, the molecules involved in the interaction between immune cells and stellate cells remain obscure. Herein, we identify the chemokine CCL5 (also known as RANTES), which is induced in murine and human liver after injury, as a central mediator of this interaction. First, we showed in patients with liver fibrosis that CCL5 haplotypes and intrahepatic CCL5 mRNA expression were associated with severe liver fibrosis. Consistent with this, we detected Ccl5 mRNA and CCL5 protein in 2 mouse models of liver fibrosis, induced by either injection of carbon tetrachloride (CCl4) or feeding on a methionine and choline-deficient (MCD) diet. In these models, Ccl5-/- mice exhibited decreased hepatic fibrosis, with reduced stellate cell activation and immune cell infiltration. Transplantation of Ccl5-deficient bone marrow into WT recipients attenuated liver fibrosis, identifying infiltrating hematopoietic cells as the main source of Ccl5. We then showed that treatment with the CCL5 receptor antagonist Met-CCL5 inhibited cultured stellate cell migration, proliferation, and chemokine and collagen secretion. Importantly, in vivo administration of Met-CCL5 greatly ameliorated liver fibrosis in mice and was able to accelerate fibrosis regression. Our results define a successful therapeutic approach to reduce experimental liver fibrosis by antagonizing Ccl5 receptors.

Cavitating mesenteric lymph node syndrome: a rare complication of refractory celiac disease.

Celiac disease is an immune-mediated enteropathy characterized by mucosal inflammation and villous atrophy of the small bowel upon exposure to ingested gluten. Refractory celiac disease (RCD), defined as persisting villous atrophy with crypt hyperplasia despite strict gluten-free diet, is a rare form of celiac disease with poor prognosis due to a higher rate of severe complications such as life-threatening malnutrition or the development of intestinal T-cell lymphoma. The cavitating mesenteric lymph node syndrome (CMLNS) represents a rare complication of celiac disease with unknown pathogenesis which is associated with but not restricted to RCD and not necessarily associated with a malignant course. We here report a 64-year-old patient who was referred to us with a history of refractory celiac disease. During further diagnostic work-up multiple intraabdominal cystic structures were detected by a computed tomography scan and magnetic resonance imaging. A laparotomy was performed to exclude T-cell lymphoma. Histology of the intraabdominal cysts revealed the diagnosis of cavitating mesenteric lymph node syndrome as the underlying cause of the masses. Steroid therapy was initiated which led to complete regression of diarrhoea but did not induce a diminution of mesenteric lymph nodes. Three years after the diagnosis of CMLNS, the patient presented with an acute abdomen due to a small bowel perforation caused by an enteropathy associated T-cell lymphoma. We discuss the differential diagnoses of intraabdominal masses in celiac disease and review the current literature on CMLNS.

Lack of interleukin-6/glycoprotein 130/signal transducers and activators of transcription-3 signaling in hepatocytes predisposes to liver steatosis and injury in mice.

UNLABELLED: A deregulated cytokine balance is involved in triggering the sequence from steatosis to nonalcoholic steatohepatitis, ultimately leading to liver fibrosis and cancer. To better define the role of proinflammatory interleukin-6 (IL-6)-type cytokines in hepatocytes we investigated the role of IL-6 and its shared receptor, glycoprotein 130 (gp130), in a mouse model of steatohepatitis. IL-6(-/-) mice were fed a choline-deficient, ethionine-supplemented (CDE) diet. Conditional gp130 knockout and knockin mice were used to achieve hepatocyte-specific deletion of gp130 (gp130(Deltahepa)), gp130-dependent rat sarcoma (Ras)-(gp130(DeltahepaRas)), and signal transducers and activators of transcription (STAT)-(gp130(DeltahepaSTAT)) activation. CDE-treated IL-6(-/-) mice showed a significant hepatic steatosis at 2 weeks after feeding. The mice rapidly developed elevated fasting blood glucose, insulin serum levels, and transaminases. To better define IL-6-dependent intracellular pathways, specifically in hepatocytes, we next treated gp130(Deltahepa) mice with a CDE diet. These animals also developed a marked steatosis with hyperglycemia and displayed elevated insulin serum levels. Additionally, gp130(Deltahepa) animals showed an imbalanced inflammatory response with increased hepatic tumor necrosis factor-alpha and decreased adiponectin messenger RNA levels. Dissecting the hepatocyte-specific gp130-dependent pathways revealed a similar disease phenotype in gp130(DeltahepaSTAT) mice, whereas gp130(DeltahepaRas) animals were protected. In CDE-treated mice lack of gp130-STAT3 signaling was associated with immune-cell-infiltration, jun kinase-activation, a blunted acute-phase-response, and elevated transaminases. Furthermore, gp130(Deltahepa) and gp130(DeltahepaSTAT) mice showed beginning signs of liver fibrosis compared to gp130(DeltahepaRas) mice and controls. CONCLUSION: During CDE treatment mice lacking IL-6 and gp130-STAT signaling in hepatocytes are prone to hepatic metabolic changes and inflammation. This ultimately leads to progressive steatohepatitis with signs of liver remodeling. Thus, the presented model allows one to further dissect the role of IL-6/gp130-type signaling in hepatocytes during fatty liver degeneration to define new therapeutic targets in metabolic liver diseases.

The chemokine scavenging receptor D6 limits acute toxic liver injury in vivo.

The chemokine decoy receptor D6 is a promiscuous chemokine receptor lacking classical signaling functions. It negatively regulates inflammation by targeting CC chemokines to cellular internalization and degradation. Here we analyze the function of D6 in acute CCl(4)-induced liver damage in constitutive D6(-/-) and wild-type mice. The degree of liver injury was assessed by liver histology, serum transaminases, IL-6, and TNFalpha mRNA expression. Protein levels of D6 ligands (CCL2, CCL3, CCL5) and the non-D6-ligand CXCL9 within the livers were determined by ELISAs. The intrahepatic infiltration of immune cells was characterized by FACS. Genetic deletion of D6 led to prolonged liver damage after acute CCl(4) administration. The augmented liver damage in D6(-/-) mice was associated with increased protein levels of intrahepatic inflammatory chemokines CCL2, CCL3, and CCL5 after 48 h, whereas CXCL9 was not different between knockout and wild-type mice. Functionally, increased intra-hepatic CC chemokine concentrations led to increased infiltration of CD45(+) leukocytes, which were mainly identified as T and NK cells. In conclusion, the chemokine scavenger receptor D6 has a non-redundant role in acute toxic liver injury in vivo. These results support the importance of post-translational chemokine regulation and describe a new mechanism of immune modulation within the liver.

c-Met confers protection against chronic liver tissue damage and fibrosis progression after bile duct ligation in mice.

BACKGROUND & AIMS: The hepatocyte growth factor (HGF)/mesenchymal-epithelial transition factor (c-Met) system is an essential inducer of hepatocyte growth and proliferation. Although a fundamental role for the HGF receptor c-Met has been shown in acute liver regeneration, its cell-specific role in hepatocytes during chronic liver injury and fibrosis progression has not been determined. METHODS: Hepatocyte-specific c-Met knockout mice (c-Met(Delta hepa)) using the Cre-loxP system were studied in a bile duct ligation (BDL) model. Microarray analyses were performed to define HGF/c-Met-dependent gene expression. RESULTS: Two strategies for c-Met deletion in hepatocytes to generate hepatocyte-specific c-Met knockout mice were tested. Early deletion during embryonic development was lethal, whereas post-natal Cre expression was successful, leading to the generation of viable c-Met(Delta hepa) mice. BDL in these mice resulted in extensive necrosis and lower proliferation rates of hepatocytes. Gene array analysis of c-Met(Delta hepa) mice revealed a significant reduction of anti-apoptotic genes in c-Met-deleted hepatocytes. These findings could be tested functionally because c-Met(Delta hepa) mice showed a stronger apoptotic response after BDL and Jo-2 stimulation. The phenotype was associated with increased expression of proinflammatory cytokines (tumor necrosis factor-alpha and interleukin-6) and an enhanced recruitment of neutrophils. Activation of these mechanisms triggered a stronger profibrogenic response as evidenced by increased transforming growth factor-beta(1), alpha-smooth muscle actin, collagen-1alpha messenger RNA expression, and enhanced collagen-fiber staining in c-Met(Delta hepa) mice. CONCLUSIONS: Our results show that deletion of c-Met in hepatocytes leads to more liver cell damage and fibrosis in a chronic cholestatic liver injury model because c-Met triggers survival signals important for hepatocyte recovery.

Longitudinal monocyte human leukocyte antigen-DR expression is a prognostic marker in critically ill patients with decompensated liver cirrhosis.

BACKGROUND: Critical illness in cirrhotic patients is associated with a poor prognosis and increased susceptibility to infections. Monocyte HLA-DR expression is decreased in cirrhotic patients, but its prognostic value has not been investigated prospectively. METHODS: Thirty-eight critically ill patients with decompensated liver cirrhosis were included in this prospective study. On admission to the intensive care unit (ICU), inflammatory parameters (C-reactive protein, procalcitonin and lipopolysaccharide-binding protein), interleukin (IL)-10, interferon (IFN)-gamma serum levels, tumour necrosis factor (TNF)-alpha ex vivo stimulation (whole blood assay) and HLA-DR expression on monocytes (FACS analysis) were determined. Immune parameters were furthermore measured every third day until discharge from the ICU or death of the patients. RESULTS: Intensive care unit mortality of the cirrhotic patients was 34.2%. During admission, TNF ex vivo, IFN-gamma and HLA-DR expression were lower in non-survivors (all P<0.05), while IL-10 levels were increased in non-survivors compared with survivors (P=0.001). However, individual values clearly overlapped between groups. Prospective analysis revealed that monocyte HLA-DR expression remained stable or increased in survivors, but decreased in non-survivors (P=0.002). A decrease in HLA-DR expression between admission and day 3 was strongly associated with decreased IFN-gamma levels and increased ICU mortality (hazard ratio 3.36, P=0.008), mostly owing to late sepsis. This association was independent of the sequential organ failure assessment and model for end-stage liver disease score. CONCLUSIONS: Here we establish the relative HLA-DR expression (admission/day 3) as a prognostic marker for ICU mortality in critically ill cirrhotic patients. These results may guide the evaluation of immune-modulating therapies in these patients.

The Marburg I variant (G534E) of the factor VII-activating protease determines liver fibrosis in hepatitis C infection by reduced proteolysis of platelet-derived growth factor BB.

UNLABELLED: Genetic risk factors play an important role for the progression of liver fibrosis in chronic hepatitis C virus (HCV) infection, but functional data on specific alleles and their related proteins are limited. Platelet-derived growth factor BB (PDGF-BB) is one of the strongest mitogens for hepatic stellate cells and is considered as a critical soluble mediator of liver fibrosis in vitro and in vivo. The biological activity of PDGF-BB is dependent on its degradation by the factor VII-activating protease (FSAP). Here, we demonstrate that a coding polymorphism (G534E) in the gene for FSAP is significantly associated with severe HCV-induced liver fibrosis (odds ratio, 2.59; P = 0.017), which is independent of age, gender, and presence of diabetes in multivariate analysis. These genetic findings were replicated in a cohort of patients with liver transplantation due to HCV-induced cirrhosis (OR, 2.56; P = 0.011). Functional dissection of the association demonstrates that the single amino acid change encoded by G534E in the FSAP protein does not influence PDGFbeta receptor or alpha-smooth muscle actin expression but completely abrogates FSAP-mediated inhibition of PDGF-BB-induced proliferation of primary stellate cells in vitro. CONCLUSION: The G534E variant of FSAP is a risk locus for HCV-induced liver fibrosis and cirrhosis by determining PDGF-BB-mediated hepatic stellate cell proliferation through a single amino acid substitution in FSAP. FSAP G534E might be useful for risk stratification in patients with HCV infection.