Nrf2 induces malignant transformation of hepatic progenitor cells by inducing ß-catenin expression.

The Nrf2 signaling pathway prevents cancer initiation, but genetic mutations that activate this pathway are found in various types of cancer. The molecular mechanisms underlying this Janus-headed character are still not understood. Here, we show that sustained Nrf2 activation induces proliferation and dedifferentiation of a Wnt-responsive perivenular hepatic progenitor cell population, transforming them into metastatic cancer cells. The neoplastic lesions display many histological features known from human hepatoblastoma. We describe an Nrf2-induced upregulation of ß-catenin expression and its activation as the underlying mechanism for the observed malignant transformation. Thus, we have identified the Nrf2-ß-catenin axis promoting proliferation of hepatic stem cells and triggering tumorigenesis. These findings support the concept that different functional levels of Nrf2 control both the protection against various toxins as well as liver regeneration by activating hepatic stem cells. Activation of the hepatic stem cell compartment confers the observation that unbridled Nrf2 activation may trigger tumorigenesis.

[Effects of SARS-CoV-2 Infection on Symptoms and Therapy of Inflammatory Bowel Disease]. / Auswirkungen einer SARS-CoV-2-Infektion auf Symptomatik und Therapie chronisch-entzündlicher Darmerkrankungen.

INTRODUCTION: The influence of a SARS-CoV-2 infection on inflammatory bowel disease (IBD) has not yet been well characterized and it is unclear whether this requires an adaptation of the immunosuppressive therapy. METHODS: A national register was established for the retrospective documentation of clinical parameters and changes in immunosuppressive therapy in SARS-CoV-2 infected IBD patients. RESULTS: In total, only 3 of 185 IBD patients (1.6 %) were tested for SARS-CoV-2 infection because of abdominal symptoms. In the course of COVID-19 disease, 43.5 % developed diarrhea, abdominal pain or hematochezia (risk of hospitalization with vs. without abdominal symptoms: 20.0 % vs. 10.6 %, p < 0.01). With active IBD at the time of SARS-CoV-2 detection, there was an increased risk of hospitalization (remission 11.2 %, active IBD 23.3 % p < 0.05). IBD-specific therapy remained unchanged in 115 patients (71.4 %); the most common change was an interruption of systemic therapy (16.2 %). DISCUSSION: New abdominal symptoms often appeared in SARS-CoV-2 infected IBD patients. However, these only rarely led to SARS-CoV-2 testing. A high IBD activity at the time of SARS-CoV-2 detection was associated with an increased risk of hospitalization.

Reevaluation of Lung Injury in TNF-Induced Shock: The Role of the Acid Sphingomyelinase.

Tumor necrosis factor (TNF) is a well-known mediator of sepsis. In many cases, sepsis results in multiple organ injury including the lung with acute respiratory distress syndrome (ARDS). More than 20-year-old studies have suggested that TNF may be directly responsible for organ injury during sepsis. However, these old studies are inconclusive, because they relied on human rather than conspecific TNF, which was contaminated with endotoxin in most studies. In this study, we characterized the direct effects of intravenous murine endotoxin-free TNF on cardiovascular functions and organ injury in mice with a particular focus on the lungs. Because of the relevance of the acid sphingomyelinase in sepsis, ARDS, and caspase-independent cell death, we also included acid sphingomyelinase-deficient (ASM-/-) mice. ASM-/- and wild-type (WT) mice received 50 µg endotoxin-free murine TNF intravenously alone or in combination with the pan-caspase inhibitor carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]-fluoromethylketone (zVAD) and were ventilated at low tidal volume while lung mechanics were followed. Blood pressure was stabilized by intra-arterial fluid support, and body temperature was kept at 37°C to delay lethal shock and to allow investigation of blood gases, lung histopathology, proinflammatory mediators, and microvascular permeability 6 hours after TNF application. Besides the lungs, also the kidneys and liver were examined. TNF elicited the release of inflammatory mediators and a high mortality rate, but failed to injure the lungs, kidneys, or liver of healthy mice significantly within 6 hours. Mortality in WT mice was most likely due to sepsis-like shock, as indicated by metabolic acidosis, high procalcitonin levels, and cardiovascular failure. ASM-/- mice were protected from TNF-induced hypotension and reflex tachycardia and also from mortality. In WT mice, intravenous exogenous TNF does not cause organ injury but induces a systemic inflammatory response with cardiovascular failure, in which the ASM plays a role.

Faecal Micro-RNAs in Inflammatory Bowel Diseases.

BACKGROUND AND AIMS: Faecal biomarkers are used as indicators of disease activity in inflammatory bowel diseases [IBD], which include Crohn's disease [CD] and ulcerative colitis [UC]. Micro-RNAs [miRNAs] are small non-coding RNAs detectable in extracellular fluids and can be used as clinical biomarkers. The aim of this study was to determine if faecal miRNA composition is altered in IBD. METHODS: More than 800 different human faecal miRNAs were measured in stool samples from control individuals and patients with active CD by using NanoString technology. Selected miRNAs were quantified by qRT-PCR in faeces, serum and intestinal tissue of controls [n = 23] and patients with inactive or active CD [n = 22, n = 22] or UC [n = 11, n = 24] as well as patients with Clostridium difficile infection [CDI, n = 8]. RESULTS: In total, 150 miRNAs were significantly detected in faeces from controls and patients, and multivariate analyses showed that CD patients with high disease activities had a distinct miRNA profile and that miR-223 and miR-1246 were distinct from other faecal miRNAs. In a larger cohort, active UC patients displayed significantly higher levels of miR-223 and miR-1246 than controls while patients with CDI had higher levels of faecal miR-1246 but not miR-223. No differences were noted in serum samples. CONCLUSIONS: To our knowledge, this is the first comprehensive screen of faecal miRNAs performed in IBD. Further investigation will aim to confirm these findings in a larger cohort and to understand the biological function and cellular sources of faecal miRNAs.

Fecal Eosinophil Cationic Protein Is a Diagnostic and Predictive Biomarker in Young Adults with Inflammatory Bowel Disease.

BACKGROUND AND AIMS: Fecal biomarkers are important non-invasive markers monitoring disease activity in inflammatory bowel disease (IBD). We compared the significance of fecal eosinophil cationic protein (fECP) and fecal calprotectin (fCal). METHODS: fECP and fCal were measured in patients with Crohn's disease (CD, n = 97), ulcerative colitis (UC, n = 53), Clostridioides difficile infection (CDI, n = 9), primary food allergy (PFA, n = 11), pollen-associated food allergy (n = 25) and non-inflammatory controls (n = 78). Results were correlated with clinical and endoscopic IBD activity scores. RESULTS: fECP was significantly elevated in CD, UC, CDI and PFA compared to controls. fCal was significantly increased in CD, UC and CDI. fECP had lower diagnostic accuracy than fCal (area under the curve (AUC) = 0.88) in differentiating between endoscopically active and inactive patients with IBD (AUC = 0.77, ROC analysis). In contrast to fCal, fECP correlated negatively with age and levels were also elevated in clinically and endoscopically inactive patients with IBD <45 years (endoscopically inactive IBD vs controls; AUC for fECP = 0.86; AUC for fCal = 0.62). However, in those patients with low inflammatory activity (fCal <250 mg/kg), high fECP indicated the need for treatment modification or surgery (fECP <200 µg/kg = 22%; 200-600 µg/kg = 44%; >600 µg/kg = 82%) at month 48 of follow-up. CONCLUSIONS: fECP is a diagnostic and prognostic marker in young patients with IBD in remission.

The "Aachen sings" study ("Aachen choir engagement study into GERD symptoms"): moderate singing and breathing exercises in a choir reduce reflux symptoms - a cohort study in non-specialist choristers.

BACKGROUND: The influence of singing activities and breathing exercises on the presence of gastroesophageal reflux disease (GERD) symptoms is not clear. While an Austrian study found symptom reduction, an Italian study showed more symptoms in professional opera choristers. These contradictory results may be due to differential intensity of the singing exercises. We therefore developed a questionnaire to investigate the presence of GERD typical symptoms and defined GERD in nonprofessional choristers with moderate singing activity and breathing exercises and compared the results to those from related non-singing control persons. METHODS: 434 actively engaged lay-choir persons and 310 non-singing friends or relatives answered questions in a questionnaire regarding basic data, singing habits, GERD symptoms, and past or present diagnostic events and medications. RESULTS: Non-singing control persons experienced more frequently heartburn (1.1 ±â€Š4.1 vs. 0.5 ±â€Š1.2 episodes/week, p = 0.001) and acid regurgitation (0.9 ±â€Š4.1 vs. 0.5 ±â€Š1.3 episodes/week, p < 0.001) and had more often already received the diagnosis of GERD (16.8 % vs. 10.4 %, p = 0.011). From the persons without known GERD, members of the control cohort more often fulfilled the simplified diagnostic criteria of GERD (14.3 % vs. 5.1 %, p < 0.001). A multivariate analysis identified non-singing, high body mass index, and smoking as significant risk factors for the presence of GERD symptoms. CONCLUSION: The frequency of reflux symptoms and GERD is probably still increasing. Moderate singing activities and breathing exercises seem to be helpful in avoiding reflux symptoms such as heartburn and acid regurgitation.

Nrf2 Ameliorates DDC-Induced Sclerosing Cholangitis and Biliary Fibrosis and Improves the Regenerative Capacity of the Liver.

The Nrf2 pathway protects against oxidative stress and induces regeneration of various tissues. Here, we investigated whether Nrf2 protects from sclerosing cholangitis and biliary fibrosis and simultaneously induces liver regeneration. Diet containing 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) was fed to Nrf2-KO mice (Nrf2-/-), mice with liver-specific hyperactivated Nrf2 (HKeap1-/-) and wild-type (WT) littermates to induce cholangitis, liver fibrosis, and oval cell expansion. HKeap1-/--mice were protected from almost all DDC-induced injury compared with WT and Nrf2-/-. Liver injury in Nrf2-/- and WT mice was mostly similar, albeit Nrf2-/- suffered more from DDC diet as seen for several parameters. Nrf2 activity was especially important for the expression of the hepatic efflux transporters Abcg2 and Abcc2-4, which are involved in hepatic toxin elimination. Surprisingly, cell proliferation was more enhanced in Nrf2-/-- and HKeap1-/--mice compared with WT. Interestingly, Nrf2-/--mice failed to sufficiently activate oval cell expansion after DDC treatment and showed almost no resident oval cell population under control conditions. The resident oval cell population of untreated HKeap1-/--mice was increased and DDC treatment resulted in a stronger oval cell expansion compared with WT. We provide evidence that Nrf2 activation protects from DDC-induced sclerosing cholangitis and biliary fibrosis. Moreover, our data establish a possible role of Nrf2 in oval cell expansion.

Myeloid cells require gp130 signaling for protective anti-inflammatory functions during sepsis.

Sepsis represents a major health problem worldwide because of high mortality rates and cost-intensive therapy. Immunomodulatory strategies as a means of controlling overshooting inflammatory responses during sepsis have thus far not been effective, and there is a general paucity of new therapies. Regulatory immune cells have been shown to play important roles in limiting systemic inflammation. However, the signals inducing a regulatory phenotype in myeloid cells during infection are unknown. Here, we report that myeloid cell-intrinsic glycoprotein 130 (gp130) signals constitute a critical element for immune homeostasis during polymicrobial sepsis. We identify an essential role for gp130 signaling in myeloid cells during M2 macrophage polarization in vitro and in vivo. Myeloid cell-specific deletion of gp130 signaling leads to a defective M2 macrophage polarization followed by exacerbated inflammatory responses and increased mortality during sepsis. These data provide new insights into the molecular basis of M1 and M2 phenotypic dichotomy and identify gp130 as a key regulator of immune homeostasis during sepsis. Our study highlights the Janus-faced role of IL-6 family cytokines during inflammation, which may explain the failure of IL-6-targeted anti-inflammatory approaches in the treatment of sepsis.-Sackett, S. D., Otto, T., Mohs, A., Sander, L. E., Strauch, S., Streetz, K. L., Kroy, D. C., Trautwein, C. Myeloid cells require gp130 signaling for protective anti-inflammatory functions during sepsis.

c-Met Signaling Protects from Nonalcoholic Steatohepatitis- (NASH-) Induced Fibrosis in Different Liver Cell Types.

Nonalcoholic steatohepatitis (NASH) is the most common chronic, progressive liver disease in Western countries. The significance of cellular interactions of the HGF/c-Met axis in different liver cell subtypes and its relation to the oxidative stress response remains unclear so far. Hence, the present study is aimed at investigating the role of c-Met and the interaction with the oxidative stress response during NASH development in mice and humans. Conditional c-Met knockout (KO) lines (LysCre for Kupffer cells/macrophages, GFAPCre for α-SMA+ and CK19+ cells and MxCre for bone marrow-derived immune cells) were fed chow and either methionine-choline-deficient diet (MCD) for 4 weeks or high-fat diet (HFD) for 24 weeks. Mice lacking c-Met either in Kupffer cells, α-SMA+ and CK19+ cells, or bone marrow-derived immune cells displayed earlier and faster progressing steatohepatitis during dietary treatments. Severe fatty liver degeneration and histomorphological changes were accompanied by an increased infiltration of immune cells and a significant upregulation of inflammatory cytokine expression reflecting an earlier initiation of steatohepatitis development. In addition, animals with a cell-type-specific deletion of c-Met exhibited a strong generation of reactive oxygen species (ROS) by dihydroethidium (hydroethidine) (DHE) staining showing a significant increase in the oxidative stress response especially in LysCre/c-Metmut and MxCre/c-Metmut animals. All these changes finally lead to earlier and stronger fibrosis progression with strong accumulation of collagen within liver tissue of mice deficient for c-Met in different liver cell types. The HGF/c-Met signaling pathway prevents from steatosis development and has a protective function in the progression to steatohepatitis and fibrosis. It conveys an antifibrotic role independent on which cell type c-Met is missing (Kupffer cells/macrophages, α-SMA+ and CK19+ cells, or bone marrow-derived immune cells). These results highlight a global protective capacity of c-Met in NASH development and progression.

Inhibition of Caspase-8 does not protect from alcohol-induced liver apoptosis but alleviates alcoholic hepatic steatosis in mice.

Hepatic apoptosis is involved in the progression of alcoholic liver disease (ALD). Caspase-8, the apical initiator in death receptor-mediated apoptosis, has been implicated in acute liver injury and in non-alcoholic steatohepatitis. However, the relevance of Caspase-8 in the pathogenesis of ALD remains unclear. In the present study, we investigated the impact of Caspase-8 in human and murine alcohol-induced apoptosis and in ALD. We investigated human samples from ALD patients, primary mouse hepatocytes, and hepatocyte-specific Caspase-8 knockout (Casp8Δhepa) mice in acute and chronic models of ethanol (EtOH) administration. Caspase-8 activation was detected in liver biopsies from ALD patients, as well as in livers of wild-type (WT) mice after chronic ethanol feeding for 8 weeks using the Lieber-DeCarli model. Lack of Caspase-8 expression in Casp8Δhepa animals failed to prevent alcohol-induced liver damage and apoptosis. Instead, inhibition of Caspase-8 shifted the ethanol-induced death signals towards pronounced activation of the intrinsic, mitochondria-dependent apoptosis pathway in Casp8Δhepa livers involving enhanced release of cytochrome c, stronger Caspase-9 activation and specific morphological changes of mitochondria. In vitro and in vivo intervention using a pan-caspase inhibitor markedly attenuated alcohol-induced hepatocyte damage in a Caspase-8-independent manner. Surprisingly, EtOH-fed Casp8Δhepa mice displayed significantly attenuated steatosis and reduced hepatic triglyceride and free fatty acids content. Caspase-8 is dispensable for alcohol-induced apoptosis, but plays an unexpected role for alcohol-dependent fat metabolism. We provide evidence that simultaneous inhibition of extrinsic and intrinsic apoptosis signaling using pan-caspase inhibitors in vivo might be an optimal approach to treat alcohol-induced liver injury.

[Leptomeningeal carcinomatosis as a rare metastatic spreading of BRAF-mutated microsatellite stable colon cancer]. / Meningeosis carcinomatosa als seltener Metastasierungsweg eines BRAF-mutierten Mikrosatelliten-stabilen Kolonkarzinoms.

Leptomeningeal carcinomatosis is a rare but serious complication of solid tumors such as melanoma, breast and lung cancer, as well as gastrointestinal carcinomas. Its clinical manifestation is highly variable, presenting as radicular pain with or without neurological deficits, as well as with headaches and hallucinatory irritation symptoms. Leptomeningeal carcinomatosis is often misdiagnosed, which delays treatment. Here we report a rare case of a patient with BRAF-mutated microsatellite stable colon carcinoma with lymphatic and skeletal metastases, who developed neurological symptoms one month after the initial diagnosis of malignancy. Based on the cytological detection of tumor cells in the cerebrospinal fluid, a leptomeningeal carcinomatosis was diagnosed, despite normal findings on MRI. Intrathecal chemotherapy with methotrexate, combined with intensive systemic immunochemotherapy, resulted in a good partial remission of the underlying malignant disease. However, approximately 8 months after the start of therapy, the patient developed progressive leptomeningeal carcinomatosis and died a few weeks later.

Genetic Nrf2 Overactivation Inhibits the Deleterious Effects Induced by Hepatocyte-Specific c-met Deletion during the Progression of NASH.

We have recently shown that hepatocyte-specific c-met deficiency accelerates the progression of nonalcoholic steatohepatitis in experimental murine models resulting in augmented production of reactive oxygen species and accelerated development of fibrosis. The aim of this study focuses on the elucidation of the underlying cellular mechanisms driven by Nrf2 overactivation in hepatocytes lacking c-met receptor characterized by a severe unbalance between pro-oxidant and antioxidant functions. Control mice (c-metfx/fx), single c-met knockouts (c-metΔhepa), and double c-met/Keap1 knockouts (met/Keap1Δhepa) were then fed a chow or a methionine-choline-deficient (MCD) diet, respectively, for 4 weeks to reproduce the features of nonalcoholic steatohepatitis. Upon MCD feeding, met/Keap1Δhepa mice displayed increased liver mass albeit decreased triglyceride accumulation. The marked increase of oxidative stress observed in c-metΔhepa was restored in the double mutants as assessed by 4-HNE immunostaining and by the expression of genes responsible for the generation of free radicals. Moreover, double knockout mice presented a reduced amount of liver-infiltrating cells and the exacerbation of fibrosis progression observed in c-metΔhepa livers was significantly inhibited in met/Keap1Δhepa. Therefore, genetic activation of the antioxidant transcription factor Nrf2 improves liver damage and repair in hepatocyte-specific c-met-deficient mice mainly through restoring a balance in the cellular redox homeostasis.

ß7-Integrin and MAdCAM-1 play opposing roles during the development of non-alcoholic steatohepatitis.

BACKGROUND & AIMS: Non-alcoholic steatohepatitis (NASH) is a leading cause of chronic liver disease in Western countries. It is unclear how infiltrating leukocytes affect NASH-development. Our study aims to investigate the role of the homing/receptor, pair mucosal addressin cell adhesion molecule-1 (MAdCAM-1)/ß7-Integrin, on immune cell recruitment and disease progression in a steatohepatitis model. METHODS: Constitutive ß7-Integrin deficient (ß7-/-) and MAdCAM-1 deficient (MAdCAM-1-/-) mice were fed a high fat diet (HFD) for 26weeks or methionine-choline-deficient-diet (MCD) for 4weeks. RESULTS: ß7-/- mice displayed earlier and more progressive steatohepatitis during HFD- and MCD-treatment, while MAdCAM-1-/- mice showed less histomorphological changes. The anti-oxidative stress response was significantly weaker in ß7-/- mice as reflected by a significant downregulation of the transcription factors nuclear-factor(erythroid-derived 2)-like 2 (Nrf2) and heme-oxigenase-1 (HO-1). Additionally, stronger dihydroethidium-staining revealed an increased oxidative stress response in ß7-/- animals. In contrast, MAdCAM-1-/- mice showed an upregulation of the anti-oxidative stress response. ß7-/- animals exhibited stronger hepatic infiltration of inflammatory cells, especially neutrophils, reflecting earlier steatohepatitis initiation. Expression of regulatory T cell (TReg) markers as well as numbers of anti-inflammatory macrophages was significantly enhanced in MAdCAM-1-/- mice. Those changes finally resulted in earlier and stronger collagen accumulation in ß7-/- mice, whereas MAdCAM-1-/- mice were protected from fibrosis initiation. CONCLUSIONS: Adhesion molecule mediated effector cell migration contributes to the outcome of steatohepatitis in the HFD- and the MCD model. While MAdCAM-1 promotes steatohepatitis, ß7-Integrin unexpectedly exerts protective effects. ß7-/- mice show earlier steatohepatitis initiation and significantly stronger fibrosis progression. Accordingly, the interaction of ß7-Integrins and their receptor MAdCAM-1 provide novel targets for therapeutic interventions in steatohepatitis. LAY SUMMARY: The mucosal addressin cell adhesion molecule 1 (MAdCAM-1) is expressed in livers upon diet-induced non-alcoholic steatohepatitis (NASH). Loss of MAdCAM-1 has beneficial effects regarding the development of NASH - manifested by reduced hepatic oxidative stress and decreased inflammation. In contrast, ß7-Integrin-deficiency results in increased steatohepatitis.

Anti-food and anti-microbial IgG subclass antibodies in inflammatory bowel disease.

OBJECTIVES: Inflammatory bowel disease (IBD), particularly Crohn's disease (CD), is associated with increased microbial-specific IgG and IgA antibodies, whereas alterations of anti-food antibodies are still disputed. The knowledge about IgG subclass antibodies in IBD is limited. In this study we analysed IgG subclass antibodies specific for nutritional and commensal antigens in IBD patients and controls. METHODS: Serum IgG1, IgG2, IgG3 and IgG4 specific for wheat and milk extracts, purified ovalbumin, Escherichia coli and Bacteroides fragilis lysates and mannan from Saccharomyces cerevisiae were analysed by ELISA in patients with CD (n = 56), ulcerative colitis (UC; n = 29), acute gastroenteritis/colitis (n = 12) as well as non-inflammatory controls (n = 62). RESULTS: Anti-Saccharomyces cerevisiae antibodies (ASCA) of all IgG subclasses and anti-B. fragilis IgG1 levels were increased in CD patients compared to UC patients and controls. The discriminant validity of ASCA IgG2 and IgG4 was comparable with that of ASCA pan-IgG and IgA, whereas it was inferior for ASCA IgG1/IgG3 and anti-B. fragilis IgG1. Complicated CD defined by the presence of perianal, stricturing or penetrating disease phenotypes was associated with increased ASCA IgG1/IgG3/IgG4, anti-B. fragilis IgG1 and anti-E. coli IgG1 levels. Anti-food IgG subclass levels were not different between IBD patients and controls and did not correlate with food intolerance. In contrast to anti-microbial Abs, food-specific IgG responses were predominately of the IgG4 isotype and all food-specific IgG subclass levels correlated negatively with age. CONCLUSION: Our study supports the notion that the adaptive immune recognition of food and commensal antigens are differentially regulated.

Hepatocyte-specific Keap1 deletion reduces liver steatosis but not inflammation during non-alcoholic steatohepatitis development.

Generation of reactive oxygen species (ROS) in response to fatty acids accumulation has been classically proposed as a possible "second hit" triggering progression from simple steatosis to non-alcoholic steatohepatitis (NASH). In this study we challenged hepatocyte-specific Keap1 knockout mice (Keap1(Δhepa)) and littermate Cre- controls (Keap1(fx/fx)) with two different diet models of NASH in order to evaluate the effects of the anti-oxidant transcription factor Nrf2 over-activation on hepatic metabolism and disease progression. After 4 weeks of MCD diet the liver/body weight ratio of Keap1(Δhepa) mice was significantly higher compared to littermate controls with no differences in total body weight. Strikingly, liver histology revealed a dramatic reduction of lipid droplets confirmed by a decreased content of intra-hepatic triglycerides in Keap1(Δhepa) compared to controls. In parallel to reduced expression of genes involved in lipid droplet formation, protein expression of Liver X Receptor (LXRα/ß) and Peroxisome proliferator-activated receptor α (PPARα) was significantly decreased. In contrast, genes involved in mitochondrial lipid catabolism were markedly up-regulated in Keap1(Δhepa) livers. A similar phenotype characterized by inhibition of lipogenesis in favor of increased mitochondrial catabolic activity was also observed after 13 weeks of western diet administration. MCD-induced apoptosis was significantly dampened in Keap1(Δhepa) compared to Keap1(fx/fx) as detected by TUNEL, cleaved caspase-3 and Bcl-2 protein expression analyses. However, no differences in inflammatory F4/80- and CD11b-positive cells and pro-fibrogenic genes were detected between the two groups. Although hepatic lack of Keap1 did not ameliorate inflammation, the resulting constitutive Nrf2 over-activation in hepatocytes strongly reduced hepatic steatosis via enhanced lipid catabolism and repressed de novo lipogenesis during murine NASH development.

Nrf2 in health and disease: current and future clinical implications.

The transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2) is a major regulator of oxidative stress defence in the human body. As Nrf2 regulates the expression of a large battery of cytoprotective genes, it plays a crucial role in the prevention of degenerative disease in multiple organs. Thus it has been the focus of research as a pharmacological target that could be used for prevention and treatment of chronic diseases such as multiple sclerosis, chronic kidney disease or cardiovascular diseases. The present review summarizes promising findings from basic research and shows which Nrf2-targeting therapies are currently being investigated in clinical trials and which agents have already entered clinical practice.

The Anti-Microbial Peptide LL-37/CRAMP Is Elevated in Patients with Liver Diseases and Acts as a Protective Factor during Mouse Liver Injury.

BACKGROUND: Antimicrobial peptides (AMP) are an important defense mechanism of the innate immune system and can modulate the course of various diseases. However, their significance during liver pathogenesis is currently not well defined. METHODS: Patients with liver diseases were analyzed for LL-37/CRAMP, human beta-defensin-2 (hBD2), and complement 5a (C5a) serum levels. Mice deficient in CRAMP (Cathelicidin-related Antimicrobial Peptide), the mouse homolog for human LL-37, were fed with a methionine- and choline-deficient diet (MCD) and underwent bile-duct ligation (BDL). RESULTS: First, serum samples from patients with chronic liver diseases were investigated. Therefore, significantly enhanced levels for LL-37, hBD2, and complement C5a were detected, all of which comprise antimicrobial properties. Next, CRAMP-knockout (CRAMP-KO) mice were investigated, to better define a functional role of LL-37/CRAMP in animal models of liver diseases. MCD feeding and bile-duct ligation of CRAMP-KO mice resulted in an enhanced degree of liver injury during the early treatment phase. MCD feeding in CRAMP-KO mice led to stronger intrahepatic fat accumulation and significantly enhanced matrix remodeling, whereas BDL caused more extensive liver necrosis. At the late 28 days time point, MCD-fed CRAMP-KO mice displayed a higher intrahepatic fat load. Long-term changes in bile-duct-ligated mice included higher collagen content as a sign of enhanced fibrosis progression if CRAMP was absent. CONCLUSION: The study shows a clear correlation of antimicrobial peptide serum levels in patients with chronic liver diseases. Furthermore, we were able to demonstrate protective functions of LL-37/CRAMP in two independent mouse models of chronic liver injury.

Immunoregulation by lipids during the development of non-alcoholic steatohepatitis.

Non-alcoholic fatty liver disease (NAFLD) represents the most common liver disorder in western countries and it is commonly associated with obesity and progression of the metabolic syndrome. Comprehending a wide spectrum of pathologic features, it is currently well recognized that a key point for the integrity of hepatocyte functionality in NAFLD is the progression from simple steatosis to non-alcoholic steatohepatitis (NASH). Indeed, activation of the innate immune system in response to hepatic metabolic stresses represents a central process that determines the evolution and the reversibility of liver damage. Despite of the burden of studies published in recent years, it is still intriguingly unclear how accumulation of lipids in hepatocytes triggers the activation of the inflammatory response leading to the recruitment of infiltrating cells of extra-hepatic origins. In this review we offer a general view on recent advances pointing out how different classes of lipids are able to specifically affect hepatocytes functionality and survival, thus differently influencing the organization of the hepatic immune response. On the other hand, we gathered recent studies intending to illustrate the basic mechanisms through which several non-parenchymal hepatic and extra-hepatic cell populations get activated in response to lipids. Finally, we indicate latter findings proposing how the immune system majorly contributes to the progression of NASH.

Distinct patterns of IgG and IgA against food and microbial antigens in serum and feces of patients with inflammatory bowel diseases.

BACKGROUND: Inflammatory bowel disease (IBD) is associated with a defective intestinal barrier and enhanced adaptive immune responses against commensal microbiota. Immune responses against food antigens in IBD patients remain poorly defined. METHODS: IgG and IgA specific for food and microfloral antigens (wheat and milk extracts; purified ovalbumin; Escherichia coli and Bacteroides fragilis lysates; mannan from Saccharomyces cerevisiae) were analyzed by ELISA in the serum and feces of patients with Crohn's disease (CD; n = 52 for serum and n = 20 for feces), ulcerative colitis (UC; n = 29; n = 17), acute gastroenteritis/colitis (AGE; n = 12; n = 9) as well as non-inflammatory controls (n = 61; n = 39). RESULTS: Serum anti-Saccharomyces cerevisiae antibodies (ASCA) and anti-B. fragilis IgG and IgA levels were increased in CD patients whereas antibody (Ab) levels against E. coli and food antigens were not significantly different within the patient groups and controls. Subgroup analysis revealed that CD patients with severe diseases defined by stricturing and penetrating lesions have slightly higher anti-food and anti-microbial IgA levels whereas CD and UC patients with arthropathy have decreased anti-food IgG levels. Treatment with anti-TNF-α Abs in CD patients was associated with significantly decreased ASCA IgG and IgA and anti-E. coli IgG. In the feces specific IgG levels against all antigens were higher in CD and AGE patients while specific IgA levels were higher in non-IBD patients. Anti-food IgG and IgA levels did not correlate with food intolerance. SUMMARY: In contrast to anti-microbial Abs, we found only minor changes in serum anti-food Ab levels in specific subgroups of IBD patients. Fecal Ab levels towards microbial and food antigens show distinct patterns in controls, CD and UC patients.

Hepatic tissue environment in NEMO-deficient mice critically regulates positive selection of donor cells after hepatocyte transplantation.

BACKGROUND: Hepatocyte transplantation (HT) is a promising alternative treatment strategy for end-stage liver diseases compared with orthotopic liver transplantation. A limitation for this approach is the low engraftment of donor cells. The deletion of the I-kappa B kinase-regulatory subunit IKKγ/NEMO in hepatocytes prevents nuclear factor (NF)-kB activation and triggers spontaneous liver apoptosis, chronic hepatitis and the development of liver fibrosis and hepatocellular carcinoma. We hypothesized that NEMOΔhepa mice may therefore serve as an experimental model to study HT. METHODS: Pre-conditioned NEMOΔhepa mice were transplanted with donor-hepatocytes from wildtype (WT) and mice deficient for the pro-apoptotic mediator Caspase-8 (Casp8Δhepa). RESULTS: Transplantation of isolated WT-hepatocytes into pre-conditioned NEMOΔhepa mice resulted in a 6-7 fold increase of donor cells 12 weeks after HT, while WT-recipients showed no liver repopulation. The use of apoptosis-resistant Casp8Δhepa-derived donor cells further enhanced the selection 3-fold after 12-weeks and up to 10-fold increase after 52 weeks compared with WT donors. While analysis of NEMOΔhepa mice revealed strong liver injury, HT-recipient NEMOΔhepa mice showed improved liver morphology and decrease in serum transaminases. Concomitant with these findings, the histological examination elicited an improved liver tissue architecture associated with significantly lower levels of apoptosis, decreased proliferation and a lesser amount of liver fibrogenesis. Altogether, our data clearly support the therapeutic benefit of the HT procedure into NEMOΔhepa mice. CONCLUSION: This study demonstrates the feasibility of the NEMOΔhepa mouse as an in vivo tool to study liver repopulation after HT. The improvement of the characteristic phenotype of chronic liver injury in NEMOΔhepa mice after HT suggests the therapeutic potential of HT in liver diseases with a chronic inflammatory phenotype and opens a new door for the applicability of this technique to combat liver disease in the human clinic.