Investigations about liver regeneration after partial liver resection

Die Leberresektion stellt eine wesentliche kurative Therapie für Tumor-Erkrankungen bzw. Metastasen anderer Karzinome innerhalb der Leber dar. Hierbei ist die grundsätzliche Abfolge von zellulärer Aktivierung, Zytokinausschüttung und Produktion von Wachstumsfaktoren bis hin zur Proliferation der verschiedenen Leberzelltypen bekannt. In der vorliegenden Arbeit sollten die bisherigen Erkenntnisse erweitert werden, wobei untersucht wurde: • der Einfluss des Umfangs einer Leberresektion auf den klinischen Verlauf; • der Beitrag verschiedener Transkriptionsfaktoren und wesentlicher Signalwege, z.B. des angeborenen Immunsystems (TLR-System), vor allem in Bezug auf die Initiierung der Regeneration; • die Möglichkeiten der medikamentösen bzw. pharmakologischen Intervention nach Leberteilresektion, um z.B. in steatotischen oder anderweitig vorgeschädigten Lebern regenerative Prozesse zu unterstützen. Zunächst wurde der Einfluss des Resektionsumfangs auf die Leberregeneration mittels 70%igen sowie 90%igen Hepatektomien im Tiermodell ermittelt. Weiterhin wurde im Modell der 90%igen Leberresektion Glycin als mögliches Supplement evaluiert. Schließlich wurde der Proteasominhibitor Bortezomib, zugelassen zur Therapie des multiplen Myeloms und des Mantelzelllymphoms, sowohl in murinen KC als auch humanen Hepatozyten und im Modell der 70%igen Hepatektomie eingesetzt. Die Wirkung von Bortezomib auf die TLR-4-vermittelte Signalgebung in vitro sowie auf den postoperativen Verlauf in vivo wurde analysiert. Es zeigte sich, dass der Resektionsumfang in der Tat einen Einfluss auf den postoperativen Verlauf und die zu Grunde liegenden molekularen Mechanismen hatte. Messbar war dies durch verschlechterte Regeneration, verstärkten Gewebeschaden, verringerte Expression wesentlicher Zytokine und Wachstumsfaktoren sowie veränderter NF-kappaB-Kernlokalisation nach 90%iger Hepatektomie verglichen mit 70%iger Leberteilresektion. Zuvor war gezeigt worden, dass Fütterung einer Glycin-reichen Diät zu einem deutlich verminderten Leberschaden nach 90%iger Leberresektion führte. Diese Daten konnten in der vorliegenden Arbeit ergänzt werden, wobei eine reduzierte Zelltod-Rate und insbesondere eine abgeschwächte STAT3-Phosphorylierung beobachtet wurden, die als wesentlich für regenerative Prozesse angesehen wird. Eine pharmakologische Verbesserung des klinischen Verlaufs durch Einflussnahme auf molekulare Prozesse nach partieller Hepatektomie mittels oraler Glycin-Gabe ist möglich. Die in-vitro-Behandlung muriner KC und humaner Hepatozyten durch Bortezomib reduzierte bzw. modulierte die TLR-4-induzierte Zytokinproduktion. Hierdurch konnte gezeigt werden, dass die Proteasominhibition den NF-kappaB-Signalweg blockiert. Daher wurde Bortezomib eingesetzt, um im Tiermodell der Leberresektion TLR-4-vermittelte NF-kappaB-Aktivität zu beeinflussen. In Verbindung mit Hepatektomien erwies sich eine Bortezomib-Applikation als letal. Während die NF-kappaB-Kernlokalisation nach Leberresektion eine hohe Varianz aufwies, änderte sich die Expression von Zytokinen und Wachstumsfaktoren, die für die Regeneration relevant sind, nur geringfügig. Auch eine vermehrte Zelltod- bzw. Apoptose-Rate war nicht zu beobachten. HIF1-alpha oder eine generelle Hypoxieschädigung erscheint nach den vorliegenden Daten ebenfalls nicht oder in geringem Ausmaß an der hohen Letalität beteiligt zu sein. Die gezeigten Daten erweitern die Kenntnisse über bekannte molekulare Mechanismen der Leberregeneration und zeigen mögliche Ansatzpunkte für weiterführende Untersuchungen auf

Circulating microRNAs: promising candidates serving as novel biomarkers of acute hepatitis

Acute liver failure as life threatening condition comprises a difficult diagnostic situation to evaluate potential outcomes and therapeutic options. Thus, prognostic indicators are urgently needed for evaluation of progression of liver injury, clinical outcome, prognosis, and for therapeutic response. Recently, circulating microRNA, in particular miR-122, was described as a potential biomarker of acute liver injury after intoxication of mice. Circulating microRNA (miRNA) molecules are very stable and RNase-resistant due to protein aggregation and vesicle enclosure. Since miRNA species are known to be associated with chronic liver damage or with liver cancer, circulating miRNA patterns are suggested to serve also as reporters for progression of acute liver failure. miRNA profiling analyses using PCR arrays or next generation sequencing, may achieve identification of miRNA species that are linked to the rapid progression of acute liver injury, to the outcome of liver failure, or to the therapeutic response. Therefore, circulating miRNAs are promising, non-invasive biomarkers of future diagnostic approaches. However, normalisation of circulating miRNA levels is essential and further standardisation of miRNA quantification assays is needed

Hepatokines and adipokines in NASH-related hepatocellular carcinoma

Summary The incidence of hepatocellular carcinoma (HCC) is increasing in industrialised societies; this is likely secondary to the increasing burden of non-alcoholic fatty liver disease (NAFLD), its progressive form non- alcoholic steatohepatitis (NASH), and the metabolic syndrome. Cumulative studies suggest that NAFLD- related HCC may also develop in non-cirrhotic livers. However, prognosis and survival do not differ between NAFLD- or virus-associated HCC. Thus, research has increasingly focused on NAFLD-related risk factors to better understand the biology of hepatocarcinogenesis and to develop new diagnostic, pre- ventive, and therapeutic strategies. One important aspect thereof is the role of hepatokines and adipo- kines in NAFLD/NASH-related HCC. In this review, we compile current data supporting the use of hepatokines and adipokines as potential markers of disease progression in NAFLD or as early markers of NAFLD-related HCC. While much work must be done to elucidate the mechanisms and interactions underlying alterations to hepatokines and adipokines, current data support the possible utility of these factors – in particular, angiopoietin-like proteins, fi broblast growth factors, and apelin – for detection or even as therapeutic targets in NAFLD-related HCC.Supported by the German Research Foundation (DFG CA267/13-3; CA267/14-1) and the Wilhelm Laupitz Foundation (A.C. and O.K.)

Significance of Simple Steatosis: An Update on the Clinical and Molecular Evidence

Non-alcoholic fatty liver disease (NAFLD) is defined clinicopathologically by the accumulation of lipids in >5% of hepatocytes and the exclusion of secondary causes of fat accumulation. NAFLD encompasses a wide spectrum of liver damage, extending from simple steatosis or non-alcoholic fatty liver (NAFL) to non-alcoholic steatohepatitis (NASH)-the latter is characterized by inflammation and hepatocyte ballooning degeneration, in addition to the steatosis, with or without fibrosis. NAFLD is now the most common cause of chronic liver disease in Western countries and affects around one quarter of the general population. It is a multisystem disorder, which is associated with an increased risk of type 2 diabetes mellitus as well as liver- and cardiovascular-related mortality. Although earlier studies had suggested that NAFL is benign (i.e., non-progressive), cumulative evidence challenges this dogma, and recent data suggest that nearly 25% of those with NAFL may develop fibrosis. Importantly, NAFLD patients are more susceptible to the toxic effects of alcohol, drugs, and other insults to the liver. This is likely due to the functional impairment of steatotic hepatocytes, which is virtually undetectable by current clinical tests. This review provides an overview of the current evidence on the clinical significance of NAFL and discusses the molecular basis for NAFL development and progression.This research was funded by the German Research Foundation (DFG CA267/13-3; CA267/14-1 to A.C.) and by the Wilhelm Laupitz Foundation (A.C. and O.K.)

Significance of Simple Steatosis: An Update on the Clinical and Molecular Evidence

Non-alcoholic fatty liver disease (NAFLD) is defined clinicopathologically by the accumulation of lipids in >5% of hepatocytes and the exclusion of secondary causes of fat accumulation. NAFLD encompasses a wide spectrum of liver damage, extending from simple steatosis or non-alcoholic fatty liver (NAFL) to non-alcoholic steatohepatitis (NASH)-the latter is characterized by inflammation and hepatocyte ballooning degeneration, in addition to the steatosis, with or without fibrosis. NAFLD is now the most common cause of chronic liver disease in Western countries and affects around one quarter of the general population. It is a multisystem disorder, which is associated with an increased risk of type 2 diabetes mellitus as well as liver- and cardiovascular-related mortality. Although earlier studies had suggested that NAFL is benign (i.e., non-progressive), cumulative evidence challenges this dogma, and recent data suggest that nearly 25% of those with NAFL may develop fibrosis. Importantly, NAFLD patients are more susceptible to the toxic effects of alcohol, drugs, and other insults to the liver. This is likely due to the functional impairment of steatotic hepatocytes, which is virtually undetectable by current clinical tests. This review provides an overview of the current evidence on the clinical significance of NAFL and discusses the molecular basis for NAFL development and progression.Fil: Mazzolini Rizzo, Guillermo Daniel. Universidad Austral. Facultad de Ciencias Biomédicas. Instituto de Investigaciones en Medicina Traslacional. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Medicina Traslacional; ArgentinaFil: Sowa, Jan Peter. Ruhr Universität Bochum; AlemaniaFil: Atorrasagasti, María Catalina. Universidad Austral. Facultad de Ciencias Biomédicas. Instituto de Investigaciones en Medicina Traslacional. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Medicina Traslacional; ArgentinaFil: Kücükoglu, Özlem. Otto-von-Guericke-Universität Magdeburg; AlemaniaFil: Syn, Wing Kin. Universidad del País Vasco; España. Medical University of South Carolina; Estados Unidos. University of the Basque Country; EspañaFil: Canbay, Ali. Ruhr Universität Bochum; Alemani

SPARC expression is associated with hepatic injury in rodents and humans with non-alcoholic fatty liver disease

Mechanisms that control progression from simple steatosis to steato-hepatitis and fibrosis in patients with non-alcoholic fatty liver disease (NAFLD) are unknown. SPARC, a secreted matricellular protein, is over-expressed in the liver under chronic injury. Contribution of SPARC accumulation to disease severity is largely unknown in NAFLD. We assessed the hypothesis that SPARC is increased in livers with more necrosis and inflammation and could be associated with more fibrosis. qrt-PCR, immunohistochemistry, and ELISA were employed to localize and quantify changes in SPARC in 62 morbidly obese patients with NAFLD/NASH and in a mouse model of diet-induced-NASH. Results were correlated with the severity of NAFLD/NASH. In obese patients 2 subgroups were identified with either high SPARC expression (n = 16) or low SPARC expression (n = 46) in the liver, with a cutoff of 1.2 fold expression. High expression of SPARC paralleled hepatocellular damage and increased mRNA expression of pro-fibrogenic factors in the liver. In line with these findings, in the NASH animal model SPARC knockout mice were protected from inflammatory injury, and showed less inflammation and fibrosis. Hepatic SPARC expression is associated with liver injury and fibrogenic processes in NAFLD. SPARC has potential as preventive or therapeutic target in NAFLD patients.Fil: Mazzolini Rizzo, Guillermo Daniel. Universidad Austral. Facultad de Ciencias Biomédicas. Instituto de Investigaciones en Medicina Traslacional. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Medicina Traslacional; ArgentinaFil: Atorrasagasti, María Catalina. Universidad Austral. Facultad de Ciencias Biomédicas. Instituto de Investigaciones en Medicina Traslacional. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Medicina Traslacional; ArgentinaFil: Onorato, Agostina Mariana. Universidad Austral. Facultad de Ciencias Biomédicas. Instituto de Investigaciones en Medicina Traslacional. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Medicina Traslacional; ArgentinaFil: Peixoto, Estanislao. Universidad Austral. Facultad de Ciencias Biomédicas. Instituto de Investigaciones en Medicina Traslacional. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Medicina Traslacional; ArgentinaFil: Schlattjan, Martin. Universitat Essen; AlemaniaFil: Sowa, Jan Peter. Universitat Essen; AlemaniaFil: Sydor, Svenja. Universitat Essen; AlemaniaFil: Gerken, Guido. Universitat Essen; AlemaniaFil: Canbay, Ali. Universitat Essen; Alemani

Self-Reports on Symptoms of Alcohol Abuse: Liver Transplant Patients versus Rehabilitation Therapy Patients

Context— Self-report measures often underestimate the severity of symptoms of alcohol abuse. It is generally supposed that patients who abuse alcohol tend to minimize their drinking behavior. However, the validity of self-reports also can be influenced by external factors such as the setting. Objective— To investigate how the setting influences self-reporting on symptoms of alcohol abuse in patients with alcoholic liver disease. Design, Setting and Participants— Cross-sectional study in patients before liver transplant (n = 40) and patients in rehabilitation therapy (n = 44). Main Outcome Measure— Scores on the Munich Alcoholism Test, which consists of a self-report-scale and an expert-rating scale. Results— The discrepancy in scores on the self-report scale and the expert-rating scale differed significantly between patients before liver transplant and patients in rehabilitation therapy. Furthermore, patients in the rehabilitation therapy group reported higher alcoholism scores on the self-report questionnaire than did patients before liver transplant, but the groups did not differ in the expert evaluation value. Conclusion— The transplant setting seems to evoke minimizing in self-reports in patients with alcohol abuse. Minimizing or denying symptoms of alcohol abuse does not seem to be a specific characteristic of persons with alcohol abuse, as it is also caused by the circumstances. In the transplant setting, more attention should be given to the psychologically difficult situation for patients with potential alcohol abuse. Implementation of psychoeducational interventions in the treatment process before transplant could be a first step toward reaching this goal

Liver Injury Indicating Fatty Liver but Not Serologic NASH Marker Improves under Metformin Treatment in Polycystic Ovary Syndrome

Objective. Polycystic ovary syndrome (PCOS) is associated with obesity and insulin resistance (IR), key features of nonalcoholic steatohepatitis (NASH). Cytokeratin 18 fragments (M30) have been established as a serum marker for NASH. The insulin sensitizer metformin improves hepatic IR. This study evaluates the influence of MF on serologic NASH (sNASH) in patients with PCOS. Patients and Methods. In 89 patients, metabolic parameters, liver injury indicating fatty liver (LIFL), and M30 were assessed at baseline and after metformin treatment. Patients with initial IR were subdivided into dissolved (PCOS-exIR) and persistent IR (PCOS-PIR) after treatment and compared to an initially insulin sensitive PCOS group (PCOS-C). Results. Improvement of LIFL prevalence could be seen in PCOS-C and PCOS-exIR compared to PCOS-PIR (−19.4, resp., −12.0% versus 7.2%, Chi2 = 29.5, P<0.001) without change in sNASH prevalence. In PCOS-PIR, ALT levels increased significantly accompanied by a nominal, nonsignificant M30 increase. Conclusions. Metformin improves LIFL in subgroups of patients with PCOS without influencing sNASH. This could either indicate a missing effect of metformin on NAFLD or slowed disease progression. Further studies are needed to elucidate NAFLD in the context of PCOS and potential therapeutic options

Joint analysis of stressors and ecosystem services to enhance restoration effectiveness

With increasing pressure placed on natural systems by growing human populations, both scientists and resource managers need a better understanding of the relationships between cumulative stress from human activities and valued ecosystem services. Societies often seek to mitigate threats to these services through large-scale, costly restoration projects, such as the over one billion dollar Great Lakes Restoration Initiative currently underway. To help inform these efforts, we merged high-resolution spatial analyses of environmental stressors with mapping of ecosystem services for all five Great Lakes. Cumulative ecosystem stress is highest in near-shore habitats, but also extends offshore in Lakes Erie, Ontario, and Michigan. Variation in cumulative stress is driven largely by spatial concordance among multiple stressors, indicating the importance of considering all stressors when planning restoration activities. In addition, highly stressed areas reflect numerous different combinations of stressors rather than a single suite of problems, suggesting that a detailed understanding of the stressors needing alleviation could improve restoration planning. We also find that many important areas for fisheries and recreation are subject to high stress, indicating that ecosystem degradation could be threatening key services. Current restoration efforts have targeted high-stress sites almost exclusively, but generally without knowledge of the full range of stressors affecting these locations or differences among sites in service provisioning. Our results demonstrate that joint spatial analysis of stressors and ecosystem services can provide a critical foundation for maximizing social and ecological benefits from restoration investments. www.pnas.org/lookup/suppl/doi:10.1073/pnas.1213841110/-/DCSupplementa