Endoscopic Ultrasonography May Select Subjects Having Asymptomatic Chronic Pancreatic Hyperenzymemia Who Require a Stricter Follow-up.

OBJECTIVES: We have previously shown that at least 50% of patients with asymptomatic chronic pancreatic hyperenzymemia (ACPH) may develop morphological pancreatic alterations. Endoscopic ultrasonography (EUS) may detect small lesions, and its sensitivity seems to be higher than other imaging techniques. The aim of this study was to evaluate whether EUS may modify the management of patients having ACPH. METHODS: In 2 referral centers for pancreatic disease, a retrospective analysis of prospectively enrolled patients with ACPH was conducted. RESULTS: Seventy-three patients with ACPH were enrolled for the purpose of this study. Endoscopic ultrasonography was performed as the last examination in 45 subjects who resulted negative at previous imaging studies (abdominal ultrasound, computed tomography, magnetic resonance imaging associated with cholangiopancreatography). Using EUS in 7 subjects, abnormalities were found in the following: 3 branch-duct intraductal papillary mucinous neoplasms, 1 duodenal diverticulum, 1 annular pancreas, 1 findings suggestive of chronic pancreatitis, and 1 undefined cyst (<5 mm). CONCLUSIONS: Endoscopic ultrasonography is able to detect alteration not found by other imaging technique in 15.5% of patients with ACPH and may be useful to select those patients who require a more strict follow-up.

Serum Amyloid A Induces Inflammation, Proliferation and Cell Death in Activated Hepatic Stellate Cells.

Serum amyloid A (SAA) is an evolutionary highly conserved acute phase protein that is predominantly secreted by hepatocytes. However, its role in liver injury and fibrogenesis has not been elucidated so far. In this study, we determined the effects of SAA on hepatic stellate cells (HSCs), the main fibrogenic cell type of the liver. Serum amyloid A potently activated IκB kinase, c-Jun N-terminal kinase (JNK), Erk and Akt and enhanced NF-κB-dependent luciferase activity in primary human and rat HSCs. Serum amyloid A induced the transcription of MCP-1, RANTES and MMP9 in an NF-κB- and JNK-dependent manner. Blockade of NF-κB revealed cytotoxic effects of SAA in primary HSCs with signs of apoptosis such as caspase 3 and PARP cleavage and Annexin V staining. Serum amyloid A induced HSC proliferation, which depended on JNK, Erk and Akt activity. In primary hepatocytes, SAA also activated MAP kinases, but did not induce relevant cell death after NF-κB inhibition. In two models of hepatic fibrogenesis, CCl4 treatment and bile duct ligation, hepatic mRNA levels of SAA1 and SAA3 were strongly increased. In conclusion, SAA may modulate fibrogenic responses in the liver in a positive and negative fashion by inducing inflammation, proliferation and cell death in HSCs.

Small bowel diverticulitis with severe anemia and abdominal pain.

The current case report is related to a male patient with diabetes, obesity [body mass index (BMI) 33], hypertension and recurrence of anemia associated to melena and deep asthenia. M.P., a 60-year-old obese individual, was referred to our department by the primary care unit (PCU) of our hospital for severe anemia (Hemoglobin 6.5 g/dL) associated to episodes of melena and abdominal pain. In the past 5 mo the patient referred to the local hospital 3 times for episodes of melena (hemoglobin levels showed anemia 9.8 g/dL) but the main gastroenterological exams were completely negative (colonoscopy and gastroscopy). The PCU of our Hospital, after stabilization of the main parameters and blood transfusion for the low levels of hemoglobin, referred the patient to gastroenterologists: the patient was subjected to both colonoscopy and gastroscopy that were negative. Due to the condition of acute severe hemorrhage the patient, during the first 3 h from the access to the PCU, was subjected to arteriography that did not reveal any hemorrhagic foci or vascular alterations. The video capsule for the study of the small bowel showed the presence of blood beginning from the third portion of duodenum but deep gastroscopy did not reveal it. The patient was then subjected to double balloon endoscopy that revealed a severe diverticulosis of the small bowel with blood from the diverticula. The entero-tomografia computerizzata confirmed the diagnosis and revealed an extension of the diverticula for almost the entire small bowel (no diverticula in the colon). The patient was subjected to wide spectrum antibiotic therapy with resolution of the symptoms and stabilization of hemoglobin levels. The surgeon suggests no indication to surgery for the wide area involved from the disease and potential high risk of complication due to the high BMI. At home, the patient started a monthly therapy with rifaximin and probiotics associated to mesalazine. At present, after 12 mo from the last episode of hemorrhage, the patient is in good clinical condition, reduced his body weight of about 7 kg and the hemoglobin levels appear in slow progressive increase (last measurement 13.2 g/dL).

PDX-1 mRNA expression in endoscopic ultrasound-guided fine needle cytoaspirate: perspectives in the diagnosis of pancreatic cancer.

BACKGROUND AND AIMS: Endoscopic ultrasound-guided fine needle aspiration is routinely used in the diagnostic work up of pancreatic cancer but has a low sensitivity. Studies showed that Pancreatic Duodenal Homeobox-1 (PDX-1) is expressed in pancreatic cancer, which is associated with a worse prognosis. We aimed to verify whether the assessment of PDX-1 in endoscopic ultrasound-guided fine needle aspiration samples may be helpful for the diagnosis of pancreatic cancer. METHODS: mRNA of 54 pancreatic cancer and 25 cystic lesions was extracted. PDX-1 expression was assessed by Real-Time PCR. RESULTS: In all but two patients with pancreatic cancer, PDX-1 was expressed and was found positive in 7 patients with pancreatic cancer in which cytology was negative. The positivity was associated with a probability of 0.98 (95% CI 0.90-1.00) of having cancer and the negativity with one of 0.08 (95% CI 0.01-0.27). The probability of cancer rose to 1.00 (95% CI 0.97-1.00) for patients positive to both PDX-1 and cytology and fell to 0.0 (95% CI 0.00-0.15) in patients negative for both. CONCLUSIONS: PDX-1mRNA is detectable in samples of pancreatic cancer. Its quantification may be helpful to improve the diagnosis of pancreatic cancer.

GIV/Girdin is a central hub for profibrogenic signalling networks during liver fibrosis.

Progressive liver fibrosis is characterized by the deposition of collagen by activated hepatic stellate cells (HSCs). Activation of HSCs is a multiple receptor-driven process in which profibrotic signals are enhanced and antifibrotic pathways are suppressed. Here we report the discovery of a signalling platform comprising G protein subunit, Gαi and GIV, its guanine exchange factor (GEF), which serves as a central hub within the fibrogenic signalling network initiated by diverse classes of receptors. GIV is expressed in the liver after fibrogenic injury and is required for HSC activation. Once expressed, GIV enhances the profibrotic (PI3K-Akt-FoxO1 and TGFß-SMAD) and inhibits the antifibrotic (cAMP-PKA-pCREB) pathways to skew the signalling network in favour of fibrosis, all via activation of Gαi. We also provide evidence that GIV may serve as a biomarker for progression of fibrosis after liver injury and a therapeutic target for arresting and/or reversing HSC activation during liver fibrosis.

Activation of the developmental pathway neurogenin-3/microRNA-7a regulates cholangiocyte proliferation in response to injury.

UNLABELLED: The activation of the biliary stem-cell signaling pathway hairy and enhancer of split 1/pancreatic duodenal homeobox-1 (Hes-1/PDX-1) in mature cholangiocytes determines cell proliferation. Neurogenin-3 (Ngn-3) is required for pancreas development and ductal cell neogenesis. PDX-1-dependent activation of Ngn-3 initiates the differentiation program by inducing microRNA (miR)-7 expression. Here we investigated the role Ngn-3 on cholangiocyte proliferation. Expression levels of Ngn-3 and miR-7 isoforms were tested in cholangiocytes from normal and cholestatic human livers. Ngn-3 was knocked-down in vitro in normal rat cholangiocytes by short interfering RNA (siRNA). In vivo, wild-type and Ngn-3-heterozygous (+/-) mice were subjected to 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) feeding (a model of sclerosing cholangitis) or bile duct ligation (BDL). In the liver, Ngn-3 is expressed specifically in cholangiocytes of primary sclerosing cholangitis (PSC) patients and in mice subjected to DDC or BDL, but not in normal human and mouse livers. Expression of miR-7a-1 and miR-7a-2 isoforms, but not miR-7b, was increased in DDC cholangiocytes compared to normal ones. In normal rat cholangiocytes, siRNA against Ngn-3 blocked the proliferation stimulated by exendin-4. In addition, Ngn-3 knockdown neutralized the overexpression of insulin growth factor-1 (IGF1; promitotic effector) observed after exposure to exendin-4, but not that of PDX-1 or VEGF-A/C. Oligonucleotides anti-miR-7 inhibited the exendin-4-induced proliferation in normal rat cholangiocytes, but did not affect Ngn-3 synthesis. Biliary hyperplasia and collagen deposition induced by DDC or BDL were significantly reduced in Ngn-3(+/-) mice compared to wild-type. CONCLUSION: Ngn-3-dependent activation of miR-7a is a determinant of cholangiocyte proliferation. These findings indicate that the reacquisition of a molecular profile typical of organ development is essential for the biological response to injury by mature cholangiocytes.

HCC development is associated to peripheral insulin resistance in a mouse model of NASH.

UNLABELLED: NAFLD is the most common liver disease worldwide but it is the potential evolution to NASH and eventually to hepatocellular carcinoma (HCC), even in the absence of cirrhosis, that makes NAFLD of such clinical importance. AIM: we aimed to create a mouse model reproducing the pathological spectrum of NAFLD and to investigate the role of possible co-factors in promoting HCC. METHODS: mice were treated with a choline-deficient L-amino-acid-defined-diet (CDAA) or its control (CSAA diet) and subjected to a low-dose i.p. injection of CCl4 or vehicle. Insulin resistance was measured by the euglycemic-hyperinsulinemic clamp method. Steatosis, fibrosis and HCC were evaluated by histological and molecular analysis. RESULTS: CDAA-treated mice showed peripheral insulin resistance at 1 month. At 1-3 months, extensive steatosis and fibrosis were observed in CDAA and CDAA+CCl4 groups. At 6 months, equal increase in steatosis and fibrosis was observed between the two groups, together with the appearance of tumor. At 9 months of treatment, the 100% of CDAA+CCl4 treated mice revealed tumor versus 40% of CDAA mice. Insulin-like Growth Factor-2 (IGF-2) and Osteopontin (SPP-1) were increased in CDAA mice versus CSAA. Furthermore, Immunostaining for p-AKT, p-c-Myc and Glypican-3 revealed increased positivity in the tumors. CONCLUSIONS: the CDAA model promotes the development of HCC from NAFLD-NASH in the presence of insulin resistance but in the absence of cirrhosis. Since this condition is increasingly recognized in humans, our study provides a model that may help understanding mechanisms of carcinogenesis in NAFLD.

The role of LDH serum levels in predicting global outcome in HCC patients treated with sorafenib: implications for clinical management.

BACKGROUND: In many tumour types serumlactate dehydrogenase (LDH) levels proved to represent an indirect marker of tumour hypoxia, neo-angiogenesis and worse prognosis. As we previously reported LDH is an important predictive factor in hepatocellular carcinoma (HCC) patients undergoing transarterial chemoembolization (TACE). Sorafenib represents the therapeutic stronghold in advanced HCC patients. As a tyrosine kinase inhibitor (TKI) mainly directed against the angiogenetic pathway, the correlation of sorafenib administration with markers of hypoxia could be an important tool in patients management. Aim of our analysis was to evaluate the role of LDH pre-treatment levels and its variation during treatment in HCC patients receiving sorafenib. METHODS: 78 patients were available for our analysis. For all patients LDH values were collected within one month before the start of treatment and after the end of therapy. For study purposes we divided our patients into two groups, according to LDH pre-treatment levels, cut-off levels was determined with ROC curve analysis. Patients were, also, classified according to the variation in LDH serum levels pre- and post-treatment (increased vs decreased). RESULTS: Patients proved homogeneous for all clinical characteristics analyzed. In patients with LDH values under the cut-off median progression free survival (PFS) was 6.7 months, whereas it was 1.9 months in patients above the cut-off (p = 0.0002). Accordingly median overall survival (OS) was 13.2 months and 4.9 months (p = 0.0006). In patients with decreased LDH values after treatment median PFS was 6.8 months, and median OS was 21.0 months, whereas PFS was 2.9 months and OS 8.6 months in patients with increased LDH levels (PFS: p = 0.0087; OS: p = 0.0035). CONCLUSIONS: In our experience, LDH seemed able to predict clinical outcome in terms of PFS and OS for HCC patients treated with sorafenib. Given the correlation between LDH levels and tumour angiogenesis we can speculate that patients with high LDH pretreatment levels may be optimal candidates for other emerging therapeutic agents or strategies targeting different molecular pathways.

VEGF and VEGFR genotyping in the prediction of clinical outcome for HCC patients receiving sorafenib: the ALICE-1 study.

Although new treatment modalities changed the global approach to hepatocellular carcinoma (HCC), this disease still represents a medical challenge. Currently, the therapeutic stronghold is sorafenib, a tyrosine kinase inhibitor (TKI) directed against the vascular endothelial growth factor (VEGF) family. Previous observations suggested that polymorphisms of VEGF and its receptor (VEGFR) genes may regulate angiogenesis and lymphangiogenesis and thus tumour growth control. The aim of our study was to evaluate the role of VEGF and VEGFR polymorphisms in determining the clinical outcome of HCC patients receiving sorafenib. From a multicentre experience 148 samples (tumour or blood samples) of HCC patients receiving sorafenib were tested for VEGF-A, VEGF-C and VEGFR-1,2,3 single nucleotide polymorphisms (SNPs). Patients' progression-free survival (PFS) and overall survival (OS) were analysed. At univariate analysis VEGF-A alleles C of rs25648, T of rs833061, C of rs699947, C of rs2010963, VEGF-C alleles T of rs4604006, G of rs664393, VEGFR-2 alleles C of rs2071559, C of rs2305948 were significant predictors of PFS and OS. At multivariate analysis rs2010963, rs4604006 and BCLC (Barcelona Clinic Liver Cancer) stage resulted to be independent factors influencing PFS and OS. Once prospectively validated, the analysis of VEGF and VEGFR SNPs may represent a clinical tool to better identify HCC patients more likely to benefit from sorafenib. On the other hand, the availability of more accurate predictive factors could help avoiding unnecessary toxicities to potentially resistant patients who may be optimal candidates for different treatments interfering with other tumour molecular pathways.

Semaphorin 7A contributes to TGF-ß-mediated liver fibrogenesis.

Semaphorin7A (SEMA7A) is a membrane-anchored protein involved in immune and inflammatory responses, exerting an effect on pulmonary fibrosis. Thus, we aimed to investigate the role of SEMA7A in hepatic fibrosis. Liver injury was induced in vivo by carbon tetrachloride i.p. injection or bile duct ligation in wild-type and SEMA7A knockout (KO) mice. Human and mouse liver samples and primary mouse hepatic cell populations were used for Western blot analysis, quantitative real-time RT-PCR, and immunohistochemistry. SEMA7A is highly expressed in hepatic stellate cells (HSCs). The expression of SEMA7A and its receptor ß1-integrin subunit increase during liver injury and in activated HSCs. Transforming growth factor ß-stimulated HSCs showed increased expression of SEMA7A in a SMAD2/3-independent manner, leading to increased expression of fibrogenic and inflammation markers. This pattern was significantly blunted in SEMA7A KO HSCs. Overexpression of SEMA7A in HSCs showed increased fibrogenic and inflammation markers expression. In vivo, SEMA7A KO mice treated with carbon tetrachloride and bile duct ligation developed reduced fibrosis versus wild-type mice. Moreover, SEMA7A expression increased in liver samples of patients with fibrosis versus healthy controls. SEMA7A was expressed in the liver and was increased in the course of liver fibrosis, both in mice and in humans. SEMA7A was mainly expressed in HSCs with respect to other cell types in the liver and plays a critical role in regulating fibrosis.

Hepatic macrophages but not dendritic cells contribute to liver fibrosis by promoting the survival of activated hepatic stellate cells in mice.

UNLABELLED: Although it is well established that hepatic macrophages play a crucial role in the development of liver fibrosis, the underlying mechanisms remain largely elusive. Moreover, it is not known whether other mononuclear phagocytes such as dendritic cells (DCs) contribute to hepatic stellate cell (HSC) activation and liver fibrosis. We show for the first time that hepatic macrophages enhance myofibroblast survival in a nuclear factor kappa B (NF-κB)-dependent manner and thereby promote liver fibrosis. Microarray and pathway analysis revealed no induction of HSC activation pathways by hepatic macrophages but a profound activation of the NF-κB pathway in HSCs. Conversely, depletion of mononuclear phagocytes during fibrogenesis in vivo resulted in suppressed NF-κB activation in HSCs. Macrophage-induced activation of NF-κB in HSCs in vitro and in vivo was mediated by interleukin (IL)-1 and tumor necrosis factor (TNF). Notably, IL-1 and TNF did not promote HSC activation but promoted survival of activated HSCs in vitro and in vivo and thereby increased liver fibrosis, as demonstrated by neutralization in coculture experiments and genetic ablation of IL-1 and TNF receptor in vivo. Coculture and in vivo ablation experiments revealed only a minor contribution to NF-κB activation in HSCs by DCs, and no contribution of DCs to liver fibrosis development, respectively. CONCLUSION: Promotion of NF-κB-dependent myofibroblast survival by macrophages but not DCs provides a novel link between inflammation and fibrosis.

From NAFLD to NASH and HCC: pathogenetic mechanisms and therapeutic insights.

NAFLD is the most common liver disease worldwide but it is the potential evolution to cirrhosis and hepatocellular carcinoma (HCC) that makes NAFLD of such clinical importance. The current work provides an overview of the main mechanims and potential therapeutical insights involved in NAFLD, NASH, fibrosis and HCC progression.

New insights in hepatocellular carcinoma: from bench to bedside.

Hepatocarcinogenesis is a multistep process involving different genetic alterations that ultimately lead to malignant transformation of the hepatocyte. The liver is one of the main targets for different metastatic foci, but it represents an important and frequent locus of degeneration in the course of chronic disease. In fact, Hepatocellular carcinoma (HCC) represents the outcome of the natural history of chronic liver diseases, from the condition of fibrosis, to cirrhosis and finally to cancer. HCC is the sixth most common cancer in the world, some 630,000 new cases being diagnosed each year. Furthermore, about the 80% of people with HCC, have seen their clinical history developing from fibrosis, to cirrhosis and finally to cancer. The three main causes of HCC development are represented by HBV, HCV infection and alcoholism. Moreover, metabolic disease [starting from Non Alcoholic Fatty Liver Disease (NAFLD), Non Alcoholic Steatohepatitis (NASH)] and, with reduced frequency, some autoimmune disease may lead to HCC development. An additional rare cause of carcinogenetic degeneration of the liver, especially developed in African and Asian Countries, is represented by aflatoxin B1. The mechanisms by which these etiologic factors may induce HCC development involve a wide range of pathway and molecules, currently under investigation. In summary, the hepatocarcionogenesis results from a multifactorial process leading to the common condition of genetic changes in mature hepatocytes mainly characterized by uncontrolled proliferation and cell death. Advances in understanding the mechanism of action are fundamental for the development of new potential therapies and results primarily from the association of the research activities coming from basic and clinical science. This review article analyzes the current models used in basic research to investigate HCC activity, and the advances obtained from a basic and clinical point of view.

Liver carcinogenesis: rodent models of hepatocarcinoma and cholangiocarcinoma.

Hepatocellular carcinoma and cholangiocarcinoma are primary liver cancers, both represent a growing challenge for clinicians due to their increasing morbidity and mortality. In the last few years a number of in vivo models of hepatocellular carcinoma and cholangiocarcinoma have been developed. The study of these models is providing a significant contribution in unveiling the pathophysiology of primary liver malignancies. They are also fundamental tools to evaluate newly designed molecules to be tested as new potential therapeutic agents in a pre-clinical set. Technical aspects of each model are critical steps, and they should always be considered in order to appropriately interpret the findings of a study or its planning. The purpose of this review is to describe the technical and experimental features of the most significant rodent models, highlighting similarities or differences between the corresponding human diseases. The first part is dedicated to the discussion of models of hepatocellular carcinoma, developed using toxic agents, or through dietary or genetic manipulations. In the second we will address models of cholangiocarcinoma developed in rats or mice by toxin administration, genetic manipulation and/or bile duct incannulation or surgery. Xenograft or syngenic models are also proposed.

An oestrogen receptor ß-selective agonist exerts anti-neoplastic effects in experimental intrahepatic cholangiocarcinoma.

BACKGROUND: Cholangiocarcinoma cells over-express oestrogen receptor-ß, which displays anti-proliferative and pro-apoptotic effects. AIM: To evaluate the effects of a newly developed and highly selective oestrogen receptor-ß agonist (KB9520) on experimental intrahepatic cholangiocarcinoma. METHODS: In vitro, the effects of KB9520 on apoptosis and proliferation of HuH-28 cells, HuH-28 cells with selective oestrogen receptor-ß silencing (by small interfering RNA), HepG2 cells (oestrogen receptor-α and oestrogen receptor-ß negative) and HepER3 cells (HepG2 cells transformed to stably express oestrogen receptor-α) were evaluated. In vivo, the effects of KB9520 on experimental intrahepatic cholangiocarcinoma, induced by thioacetamide administration were tested. RESULTS: In vitro, KB9520 induced apoptosis and inhibited proliferation of HuH-28 cells. KB9520 effects were absent in cells lacking oestrogen receptor-α and ß (HepG2) and in cells expressing only oestrogen receptor-α (HepER3); its pro-apoptotic effect was impaired in cells where oestrogen receptor-ß expression was decreased by specific small interfering RNA. In vivo, KB9520 inhibited experimental intrahepatic cholangiocarcinoma development in thioacetamide-treated rats and promoted tumour regression in rats where tumour was already established. In treated animals, tumour areas showed reduced proliferation but increased apoptosis. CONCLUSIONS: KB9520 induced apoptosis in cholangiocarcinoma by selectively acting on oestrogen receptor-ß, suggesting that oestrogen receptor-ß selective agonists may be a novel and effective therapeutic option for the medical treatment of intrahepatic cholangiocarcinoma.

Glucagon-like peptide-1 receptor activation stimulates hepatic lipid oxidation and restores hepatic signalling alteration induced by a high-fat diet in nonalcoholic steatohepatitis.

BACKGROUND/AIMS: High-fat dietary intake and low physical activity lead to insulin resistance, nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Recent studies have shown an effect of glucagon-like peptide-1 (GLP-1) on hepatic glucose metabolism, although GLP-1 receptors (GLP-1r) have not been found in human livers. The aim of this study was to investigate the presence of hepatic GLP-1r and the effect of exenatide, a GLP-1 analogue, on hepatic signalling. METHODS: The expression of GLP-1r was evaluated in human liver biopsies and in the livers of high-fat diet-treated rats. The effect of exenatide (100 nM) was evaluated in hepatic cells of rats fed 3 months with the high-fat diet. RESULTS: GLP-1r is expressed in human hepatocytes, although reduced in patients with NASH. Similarly, in rats with NASH resulted from 3 months of the high-fat diet, we found a decreased expression of GLP-1r and peroxisome proliferator-activated receptor γ (PPARγ), and reduced peroxisome proliferator-activated receptor α (PPARα) activity. Incubation of hepatocytes with exenatide increased PPARγ expression, which also exerted an insulin-sensitizing action by reducing JNK phosphorylation. Moreover, exenatide increased protein kinase A (PKA) activity, Akt and AMPK phosphorylation and determined a PKA-dependent increase of PPARα activity. CONCLUSIONS: GLP-1 has a direct effect on hepatocytes, by activating genes involved in fatty acid ß-oxidation and insulin sensitivity. GLP-1 analogues could be a promising treatment approach to improve hepatic insulin resistance in patients with NAFLD/NASH.

Role and cellular source of nicotinamide adenine dinucleotide phosphate oxidase in hepatic fibrosis.

UNLABELLED: Reactive oxygen species (ROS) generated by nicotinamide adenine dinucleotide phosphate oxidase (NOX) is required for liver fibrosis. This study investigates the role of NOX in ROS production and the differential contribution of NOX from bone marrow (BM)-derived and non-BM-derived liver cells. Hepatic fibrosis was induced by bile duct ligation (BDL) for 21 days or by methionine-choline-deficient (MCD) diet for 10 weeks in wild-type (WT) mice and mice deficient in p47phox (p47phox knockout [KO]), a component of NOX. The p47phox KO chimeric mice were generated by the combination of liposomal clodronate injection, irradiation, and BM transplantation of p47phox KO BM into WT recipients and vice versa. Upon BDL, chimeric mice with p47phox KO BM-derived cells, including Kupffer cells, and WT endogenous liver cells showed a ∼25% reduction of fibrosis, whereas chimeric mice with WT BM-derived cells and p47phox KO endogenous liver cells, including hepatic stellate cells, showed a ∼60% reduction of fibrosis. In addition, p47phox KO compared to WT mice treated with an MCD diet showed no significant changes in steatosis and hepatocellular injury, but a ∼50% reduction in fibrosis. Cultured WT and p47phox KO hepatocytes treated with free fatty acids had a similar increase in lipid accumulation. Free fatty acids promoted a 1.5-fold increase in ROS production both in p47phox KO and in WT hepatocytes. CONCLUSION: NOX in both BM-derived and non-BM-derived cells contributes to liver fibrosis. NOX does not play a role in experimental steatosis and the generation of ROS in hepatocytes, but exerts a key role in fibrosis.

Clinical implications of novel aspects of biliary pathophysiology.

Cholangiocytes are the epithelial cells that line the biliary tree; they are the target of chronic diseases termed cholangiopathies, which represent a daily challenge for clinicians, since definitive medical treatments are not available yet. It is generally accepted that the progression of injury in the course of cholangiopathies, and promotion and progression of cholangiocarcinoma are at least in part due to the failure of the cholangiocytes' mechanisms of adaptation to injury. Recently, several studies on the pathophysiology of the biliary epithelium have shed some light on the mechanisms that govern cholangiocyte response to injury. These studies provide novel information to help interpret some of the clinical aspects of cholangiopathies and cholangiocarcinoma; the purpose of this review is thus to describe some of these novel findings, focusing on their significance from a clinical perspective.

c-Jun N-terminal kinase-1 from hematopoietic cells mediates progression from hepatic steatosis to steatohepatitis and fibrosis in mice.

BACKGROUND & AIMS: c-Jun N-terminal kinase (JNK) plays a pivotal role in the development of the metabolic syndrome including nonalcoholic fatty liver disease. However, the mechanism underlying the contribution of JNK to the progression from simple steatosis to steatohepatitis and liver fibrosis is unresolved. METHODS: Hepatic steatosis, inflammation, and fibrosis were examined in wild-type, jnk1(-/-), or jnk2(-/-) mice fed a choline-deficient L-amino acid-defined (CDAA) diet for 20 weeks. The functional contribution of JNK isoforms in Kupffer cells was assessed in vitro and in vivo using chimeric mice in which the hematopoietic compartment including Kupffer cells was replaced by wild-type, jnk1(-/-), or jnk2(-/-) cells. RESULTS: CDAA diet induced significantly less hepatic inflammation and less liver fibrosis despite a similar level of hepatic steatosis in jnk1(-/-) mice as compared with wild-type or jnk2(-/-) mice. CDAA diet-induced hepatic inflammation was chronic and mediated by Kupffer cells. Pharmacologic inhibition of JNK or gene deletion of jnk1 but not jnk2 repressed the expression of inflammatory and fibrogenic mediators in primary Kupffer cells. In vivo, CDAA diet induced less hepatic inflammation and liver fibrosis despite an equivalent level of hepatic steatosis in chimeric mice with jnk1(-/-) hematopoietic cells as compared with chimeric mice with wild-type or jnk2(-/-) hematopoietic cells. CONCLUSIONS: jnk1(-/-) mice are resistant to diet-induced steatohepatitis and liver fibrosis. JNK1 in hematopoietic cells, especially in Kupffer cells, contributes to the development of liver fibrosis by inducing chronic inflammation.