Complement activation induces excessive T cell cytotoxicity in severe COVID-19.

Severe COVID-19 is linked to both dysfunctional immune response and unrestrained immunopathology, and it remains unclear whether T cells contribute to disease pathology. Here, we combined single-cell transcriptomics and single-cell proteomics with mechanistic studies to assess pathogenic T cell functions and inducing signals. We identified highly activated CD16+ T cells with increased cytotoxic functions in severe COVID-19. CD16 expression enabled immune-complex-mediated, T cell receptor-independent degranulation and cytotoxicity not found in other diseases. CD16+ T cells from COVID-19 patients promoted microvascular endothelial cell injury and release of neutrophil and monocyte chemoattractants. CD16+ T cell clones persisted beyond acute disease maintaining their cytotoxic phenotype. Increased generation of C3a in severe COVID-19 induced activated CD16+ cytotoxic T cells. Proportions of activated CD16+ T cells and plasma levels of complement proteins upstream of C3a were associated with fatal outcome of COVID-19, supporting a pathological role of exacerbated cytotoxicity and complement activation in COVID-19.

Any alcohol use in NAFLD patients is associated with significant changes to the intestinal virome.

BACKGROUND AND AIMS: The prevalence of alcohol use disorder (AUD) and metabolic dysfunction-associated fatty liver disease (MAFLD) are increasing worldwide, leading to the increasing likelihood of both etiologies contributing to a patient's liver disease. However, the effects of modest alcohol use in NAFLD are controversial and more studies are needed. We compared the intestinal viromes of patients with AUD and NAFLD in order to evaluate the effect of alcohol consumption on the intestinal viromes of NAFLD patients by extracting virus-like particles and performing metagenomic sequencing. APPROACH AND RESULTS: Viral nucleic acids were extracted from fecal samples and subjected to metagenomic sequencing. We demonstrate significant differences in the intestinal viromes of NAFLD and AUD patients, and that alcohol use in NAFLD patients reclassified to MAFLD accounted for significant differences in the intestinal viromes. The relative abundance of several Lactococcus phages was more similar between AUD patients and alcohol-consuming MAFLD patients than non-alcohol-consuming MAFLD patients and control subjects, and multivariate modeling using the most discriminating Lactococcus phages could better predict alcohol use in the MAFLD population than the alcohol-associated liver disease/NAFLD Index. Significant differences in the viral composition and diversity were also seen between MAFLD patients with low and moderate alcohol consumption compared with no alcohol consumption. CONCLUSIONS: The intestinal virome of MAFLD patients who consume low to moderate amounts of alcohol are significantly different from those who do not, and many features of the intestinal virome of alcohol-consuming MAFLD patients resemble that of AUD patients.

Interleukin-18 signaling promotes activation of hepatic stellate cells in mouse liver fibrosis.

BACKGROUND AND AIMS: Nucleotide-binding oligomerization domain-like receptor-family pyrin domain-containing 3 (NLRP3) inflammasome activation has been shown to result in liver fibrosis. Mechanisms and downstream signaling remain incompletely understood. Here, we studied the role of IL-18 in hepatic stellate cells (HSCs), and its impact on liver fibrosis. APPROACH AND RESULTS: We observed significantly increased serum levels of IL-18 (128.4 pg/ml vs. 74.9 pg/ml) and IL-18 binding protein (BP; 46.50 ng/ml vs. 15.35 ng/ml) in patients with liver cirrhosis compared with healthy controls. Single cell RNA sequencing data showed that an immunoregulatory subset of murine HSCs highly expresses Il18 and Il18r1 . Treatment of cultured primary murine HSC with recombinant mouse IL-18 accelerated their transdifferentiation into myofibroblasts. In vivo , IL-18 receptor-deficient mice had reduced liver fibrosis in a model of fibrosis induced by HSC-specific NLRP3 overactivation. Whole liver RNA sequencing analysis from a murine model of severe NASH-induced fibrosis by feeding a choline-deficient, L-amino acid-defined, high fat diet showed that genes related to IL-18 and its downstream signaling were significantly upregulated, and Il18-/- mice receiving this diet for 10 weeks showed protection from fibrotic changes with decreased number of alpha smooth muscle actin-positive cells and collagen deposition. HSC activation triggered by NLRP3 inflammasome activation was abrogated when IL-18 signaling was blocked by its naturally occurring antagonist IL-18BP. Accordingly, we observed that the severe inflammatory phenotype associated with myeloid cell-specific NLRP3 gain-of-function was rescued by IL-18BP. CONCLUSIONS: Our study highlights the role of IL-18 in the development of liver fibrosis by its direct effect on HSC activation identifying IL-18 as a target to treat liver fibrosis.

Efficacy of finerenone in patients with type 2 diabetes, chronic kidney disease and altered markers of liver steatosis and fibrosis: A FIDELITY subgroup analysis.

AIM: Investigating the effect of finerenone on liver function, cardiovascular and kidney composite outcomes in patients with chronic kidney disease and type 2 diabetes, stratified by their risk of liver steatosis, inflammation and fibrosis. MATERIALS AND METHODS: Post hoc analysis stratified patients (N = 13 026) by liver fibrosis and enzymes: high risk of steatosis (hepatic steatosis index >36); elevated transaminases [alanine transaminase (ALT) >33 (males) and >25 IU/L (females)]; and fibrosis-4 (FIB-4) index scores >3.25, >2.67 and >1.30. Liver enzymes were assessed by changes in ALT, aspartate aminotransferase and gamma-glutamyl transferase. Composite kidney outcome was defined as onset of kidney failure, sustained estimated glomerular filtration rate decline ≥57% from baseline over ≥4 weeks or kidney death. Composite cardiovascular outcome was defined as cardiovascular death, non-fatal myocardial infarction, non-fatal stroke or hospitalization for heart failure. RESULTS: ALT, aspartate aminotransferase and gamma-glutamyl transferase levels were consistent between treatment groups and remained stable throughout. Finerenone consistently reduced the risk of composite kidney outcome, irrespective of altered liver tests. Higher FIB-4 score was associated with higher incidence rates of composite cardiovascular outcome. Finerenone reduced the risk of composite cardiovascular outcome versus placebo in FIB-4 subgroups by 52% (>3.25), 39% (>2.67) and 24% (>1.30) (p values for interaction = .01, .13 and .03, respectively). CONCLUSIONS: Finerenone has neutral effects on liver parameters in patients with chronic kidney disease and type 2 diabetes. Finerenone showed robust and consistent kidney benefits in patients with altered liver tests, and profound cardiovascular benefits even in patients with higher FIB-4 scores who were at high risk of developing cardiovascular complications.

Management of alcoholic hepatitis: A clinical perspective.

Alcohol-associated liver disease is the primary cause of liver-related mortality worldwide and one of the most common indications for liver transplantation. Alcoholic hepatitis represents the most acute and severe manifestation of alcohol-associated liver disease and is characterized by a rapid onset of jaundice with progressive inflammatory liver injury, worsening of portal hypertension, and an increased risk for multiorgan failure in patients with excessive alcohol consumption. Severe alcoholic hepatitis is associated with a poor prognosis and high short-term mortality. During the COVID-19 pandemic, rates of alcohol-associated hepatitis have increased significantly, underscoring that it is a serious and growing health problem. However, adequate management of alcohol-associated hepatitis and its complications in everyday clinical practice remains a major challenge. Currently, pharmacotherapy is limited to corticosteroids, although these have only a moderate effect on reducing short-term mortality. In recent years, translational studies deciphering key mechanisms of disease development and progression have led to important advances in the understanding of the pathogenesis of alcoholic hepatitis. Emerging pathophysiology-based therapeutic approaches include anti-inflammatory agents, modifications of the gut-liver axis and intestinal dysbiosis, epigenetic modulation, antioxidants, and drugs targeting liver regeneration. Concurrently, evidence is increasing that early liver transplantation is a safe treatment option with important survival benefits in selected patients with severe alcoholic hepatitis not responding to medical treatment. This narrative review describes current pathophysiology and management concepts of alcoholic hepatitis, provides an update on emerging treatment options, and focuses on the need for holistic and patient-centred treatment approaches to improve prognosis.

Clinical characteristics of patients with non-alcoholic fatty liver disease (NAFLD) in Germany - First data from the German NAFLD-Registry.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) affects more than 18 million individuals in Germany. Real-world data help to better characterize the natural history of disease and standard of care. METHODS: The German NAFLD-Registry is a prospective non-interventional study initiated by the German Liver Foundation and aims to describe clinical characteristics and observe outcomes in patients with NAFLD recruited in secondary and tertiary care. RESULTS: From this ongoing study, baseline data of the first 501 patients (mean age 54 years, 48% women) were analysed. 13 % of the study population had a high risk for advanced fibrosis (FIB-4 ≥2.67), approximately one-third had a liver stiffness value ≥9.6kPa measured by transient elastography, and the clinical diagnosis of liver cirrhosis was present in 10%. Typical comorbidities were more prevalent in high risk as compared to low risk patients (FIB-4 <1.3) including arterial hypertension (85 vs. 42%), hypercholesterolemia (39 vs. 16%), and type 2 diabetes mellitus (T2DM) (69 vs. 26%). Patients with T2DM (192/501) had a higher NAFLD disease burden as shown by liver stiffness values ≥9.6 kPa (51%) and clinical diagnosis of cirrhosis (20%). Statins were used in 22% of the main population, while in diabetic patients, metformin, GLP-1 agonists, and SGLT2 inhibitors were used in 65, 17, and 17%, respectively. Uptake of life-style interventions such as physical exercise or nutritional counselling was generally low. CONCLUSION: First data of the German NAFLD registry show that approximately every 10th patient has advanced NAFLD, highlights T2DM patients as a high-risk group and gives insights in the use of comedication and life-style interventions in secondary and tertiary care.

The fecal mycobiome in non-alcoholic fatty liver disease.

BACKGROUND & AIMS: Studies investigating the gut-liver axis have largely focused on bacteria, whereas little is known about commensal fungi. We characterized fecal fungi in patients with non-alcoholic fatty liver disease (NAFLD) and investigated their role in a fecal microbiome-humanized mouse model of Western diet-induced steatohepatitis. METHODS: We performed fungal internal transcribed spacer 2 sequencing using fecal samples from 78 patients with NAFLD, 16 controls and 73 patients with alcohol use disorder. Anti-Candida albicans (C. albicans) IgG was measured in blood samples from 17 controls and 79 patients with NAFLD. Songbird, a novel multinominal regression tool, was used to investigate mycobiome changes. Germ-free mice were colonized with feces from patients with non-alcoholic steatohepatitis (NASH), fed a Western diet for 20 weeks and treated with the antifungal amphotericin B. RESULTS: The presence of non-obese NASH or F2-F4 fibrosis was associated with a distinct fecal mycobiome signature. Changes were characterized by an increased log-ratio for Mucor sp./Saccharomyces cerevisiae (S. cerevisiae) in patients with NASH and F2-F4 fibrosis. The C. albicans/S. cerevisiae log-ratio was significantly higher in non-obese patients with NASH when compared with non-obese patients with NAFL or controls. We observed a different fecal mycobiome composition in patients with NAFLD and advanced fibrosis compared to those with alcohol use disorder and advanced fibrosis. Plasma anti-C. albicans IgG was increased in patients with NAFLD and advanced fibrosis. Gnotobiotic mice, colonized with human NASH feces and treated with amphotericin B were protected from Western diet-induced steatohepatitis. CONCLUSIONS: Non-obese patients with NAFLD and more advanced disease have a different fecal mycobiome composition to those with mild disease. Antifungal treatment ameliorates diet-induced steatohepatitis in mice. Intestinal fungi could be an attractive target to attenuate NASH. LAY SUMMARY: Non-alcoholic fatty liver disease is one of the most common chronic liver diseases and is associated with changes in the fecal bacterial microbiome. We show that patients with non-alcoholic fatty liver disease and more severe disease stages have a specific composition of fecal fungi and an increased systemic immune response to Candida albicans. In a fecal microbiome-humanized mouse model of Western diet-induced steatohepatitis, we show that treatment with antifungals reduces liver damage.

Management of Dyslipidemia in Patients with Non-Alcoholic Fatty Liver Disease.

PURPOSE OF REVIEW: Patients with non-alcoholic fatty liver disease (NAFLD), often considered as the hepatic manifestation of the metabolic syndrome, represent a population at high cardiovascular risk and frequently suffer from atherogenic dyslipidemia. This article reviews the pathogenic interrelationship between NAFLD and dyslipidemia, elucidates underlying pathophysiological mechanisms and focuses on management approaches for dyslipidemic patients with NAFLD. RECENT FINDINGS: Atherogenic dyslipidemia in patients with NAFLD results from hepatic and peripheral insulin resistance along with associated alterations of hepatic glucose and lipoprotein metabolism, gut dysbiosis, and genetic factors. Since atherogenic dyslipidemia and NAFLD share a bi-directional relationship and are both major driving forces of atherosclerotic cardiovascular disease (ASCVD) development, early detection and adequate treatment are warranted. Thus, integrative screening and management programs are urgently needed. A stepwise approach for dyslipidemic patients with NAFLD includes (i) characterization of dyslipidemia phenotype, (ii) individual risk stratification, (iii) definition of treatment targets, (iv) lifestyle modification, and (v) pharmacotherapy if indicated.

Real-life experiences with bulevirtide for the treatment of hepatitis delta-48 weeks data from a German centre.

In July 2020, the entry inhibitor bulevirtide was approved in the European Union for the treatment of chronic hepatitis delta virus (HDV) infection. We describe the first 48 weeks of bulevirtide therapy in eight patients (n = 7 male, n = 1 female; n = 3 compensated cirrhosis) treated at our centre. Median ALT values declined from 82 to 34 U/L after 48 weeks. Median HDV RNA dropped from 13 380 000 to 3135 copies/ml. One patient showed no significant response and was discontinued at week 16. Overall, we observed a favourable safety profile and a marked biochemical and virological response in the majority of our patients.

Non-alcoholic fatty liver disease (NAFLD) is associated with an increased incidence of osteoporosis and bone fractures.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) and osteoporosis are common diseases with a rising incidence worldwide. Both diseases occur in similar patient populations, however, data on their mutual influence are conflicting. Here, we aimed to evaluate the impact of NAFLD on the incidence of osteoporosis and fractures by using the Disease Analyzer database featuring data on diagnoses, prescriptions, and demographic aspects of 7.49 million cases followed in general practices in Germany. METHODS: A total of 50,689 patients with NAFLD diagnosed between 2000 and 2015 were matched by age, sex, index year, and 3 comorbidities (obesity, diabetes mellitus, and vitamin D/calcium deficiency) to a cohort of equal size without NAFLD. Incidence of osteoporosis and bone fractures were compared between both groups within 10 years from the index date. RESULTS: Within the observation period, the incidence of osteoporosis was significantly higher in the NAFLD group (6.4%) compared to patients without NAFLD (5.1%; log-rank, p < 0.001). Similar results were observed for bone fractures (12.6 vs. 10.3 %; log-rank p < 0.001). The difference was more pronounced in women compared to men and observed in all age groups >50 years of age. CONCLUSION: Our data show that NAFLD is significantly associated with osteoporosis as well as bone fractures in a large cohort of patients followed in German general practices. This finding suggests that NAFLD patients might benefit from improved monitoring for the occurrence of bone demineralization and osteoporosis, which in turn could trigger preventive therapeutic measures.

Perinatal Obesity Induces Hepatic Growth Restriction with Increased DNA Damage Response, Senescence, and Dysregulated Igf-1-Akt-Foxo1 Signaling in Male Offspring of Obese Mice.

Maternal obesity predisposes for hepato-metabolic disorders early in life. However, the underlying mechanisms causing early onset dysfunction of the liver and metabolism remain elusive. Since obesity is associated with subacute chronic inflammation and accelerated aging, we test the hypothesis whether maternal obesity induces aging processes in the developing liver and determines thereby hepatic growth. To this end, maternal obesity was induced with high-fat diet (HFD) in C57BL/6N mice and male offspring were studied at the end of the lactation [postnatal day 21 (P21)]. Maternal obesity induced an obese body composition with metabolic inflammation and a marked hepatic growth restriction in the male offspring at P21. Proteomic and molecular analyses revealed three interrelated mechanisms that might account for the impaired hepatic growth pattern, indicating prematurely induced aging processes: (1) Increased DNA damage response (γH2AX), (2) significant upregulation of hepatocellular senescence markers (Cdnk1a, Cdkn2a); and (3) inhibition of hepatic insulin/insulin-like growth factor (IGF)-1-AKT-p38-FoxO1 signaling with an insufficient proliferative growth response. In conclusion, our murine data demonstrate that perinatal obesity induces an obese body composition in male offspring with hepatic growth restriction through a possible premature hepatic aging that is indicated by a pathologic sequence of inflammation, DNA damage, senescence, and signs of a possibly insufficient regenerative capacity.

Intestinal Virome Signature Associated With Severity of Nonalcoholic Fatty Liver Disease.

BACKGROUND & AIMS: Alterations in the gut microbiome have been associated with the severity of nonalcoholic fatty liver disease (NAFLD). Previous studies focused exclusively on the bacteria in the microbiome; we investigated changes in the viral microbiome (virome) in patients with NAFLD. METHODS: In a prospective, cross-sectional, observational study, we extracted RNA and DNA virus-like particles from fecal samples from 73 patients with NAFLD: 29 patients had an NAFLD Activity Score (NAS) of 0-4, 44 patients had an NAS of 5-8 or liver cirrhosis (LCI), 37 patients had F0-F1 fibrosis, and 36 patients had F2-F4 fibrosis. As controls, 9 individuals without liver disease and 13 patients with mild primary biliary cholangitis were included in the analysis. We performed shotgun metagenomic sequencing of virus-like particles. RESULTS: Patients with NAFLD and NAS 5-8/LCI had a significant decrease in intestinal viral diversity compared with patients with NAFLD and NAS 0-4 or control individuals. The presence of more advanced NAFLD was associated with a significant reduction in the proportion of bacteriophages compared with other intestinal viruses. Using multivariate logistic regression analysis with leave-1-out cross validation, we developed a model, including a viral diversity index and simple clinical variables, that identified patients with NAS 5-8/LCI with an area under the curve of 0.95 (95% confidence interval, 0.91-0.99) and F2-F4 fibrosis with an area under the curve of 0.88 (95% confidence interval, 0.80-0.95). Addition of data on viral diversity significantly improved multivariate models, including those based on only clinical parameters or bacterial diversity. CONCLUSIONS: In a study of fecal viromes from patients with NAFLD and control individuals, we associated histologic markers of NAFLD severity with significant decreases in viral diversity and proportion of bacteriophages. We developed a model based on fecal viral diversity and clinical data that identifies patients with severe NAFLD and fibrosis more accurately than models based only on clinical or bacterial data.

Models of Gastroenteropancreatic Neuroendocrine Neoplasms: Current Status and Future Directions.

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are a rare, heterogeneous group of tumors that originate from the endocrine system of the gastrointestinal tract and pancreas. GEP-NENs are subdivided according to their differentiation into well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). Since GEP-NENs represent rare diseases, only limited data from large prospective, randomized clinical trials are available, and recommendations for treatment of GEP-NEN are in part based on data from retrospective analyses or case series. In this context, tractable disease models that reflect the situation in humans and that allow to recapitulate the different clinical aspects and disease stages of GEP-NET or GEP-NEC are urgently needed. In this review, we highlight available data on mouse models for GEP-NEN. We discuss how these models reflect tumor biology of human disease and whether these models could serve as a tool for understanding the pathogenesis of GEP-NEN and for disease modeling and pharmacosensitivity assays, facilitating prediction of treatment response in patients. In addition, open issues applicable for future developments will be discussed.

Combined analysis of gut microbiota, diet and PNPLA3 polymorphism in biopsy-proven non-alcoholic fatty liver disease.

BACKGROUND AND AIMS: Non-alcoholic fatty liver disease (NAFLD) is a global health burden. Risk factors for disease severity include older age, increased body mass index (BMI), diabetes, genetic variants, dietary factors and gut microbiota alterations. However, the interdependence of these factors and their individual impact on disease severity remain unknown. METHODS: In this cross-sectional study, we performed 16S gene sequencing using fecal samples, collected dietary intake, PNPLA3 gene variants and clinical and liver histology parameters in a well-described cohort of 180 NAFLD patients. Principal component analyses were used for dimensionality reduction of dietary and microbiota data. Simple and multiple stepwise ordinal regression analyses were performed. RESULTS: Complete data were available for 57 NAFLD patients. In the simple regression analysis, features associated with the metabolic syndrome had the highest importance regarding liver disease severity. In the multiple regression analysis, BMI was the most important factor associated with the fibrosis stage (OR per kg/m2 : 1.23, 95% CI 1.10-1.37, P < .001). The PNPLA3 risk allele had the strongest association with the histological grade of steatosis (OR 5.32, 95% CI 1.56-18.11, P = .007), followed by specific dietary patterns. Low abundances of Faecalibacterium, Bacteroides and Prevotella and high abundances of Gemmiger were associated with the degree of inflammation, ballooning and stages of fibrosis, even after taking other cofactors into account. CONCLUSIONS: BMI had the strongest association with histological fibrosis, but PNPLA3 gene variants, gut bacterial features and dietary factors were all associated with different histology features, which underscore the multifactorial pathogenesis of NAFLD.

From Liver Cirrhosis to Cancer: The Role of Micro-RNAs in Hepatocarcinogenesis.

In almost all cases, hepatocellular carcinoma (HCC) develops as the endpoint of a sequence that starts with chronic liver injury, progresses to liver cirrhosis, and finally, over years and decades, results in liver cancer. Recently, the role of non-coding RNA such as microRNA (miRNA) has been demonstrated in the context of chronic liver diseases and HCC. Moreover, data from a phase II trial suggested a potential role of microRNAs as therapeutics in hepatitis-C-virus infection, representing a significant risk factor for development of liver cirrhosis and HCC. Despite progress in the clinical management of chronic liver diseases, pharmacological treatment options for patients with liver cirrhosis and/or advanced HCC are still limited. With their potential to regulate whole networks of genes, miRNA might be used as novel therapeutics in these patients but could also serve as biomarkers for improved patient stratification. In this review, we discuss available data on the role of miRNA in the transition from liver cirrhosis to HCC. We highlight opportunities for clinical translation and discuss open issues applicable to future developments.

Cytolysin-positive Enterococcus faecalis is not increased in patients with non-alcoholic steatohepatitis.

Several studies show associations between gut bacterial dysbiosis and chronic liver diseases, but causative mechanisms are largely unclear. We recently identified cytolysin, a bacterial exotoxin expressed and secreted by Enterococcus faecalis to cause liver damage in the setting of alcohol-related liver disease. Cytolysin was increased and highly correlated with liver disease severity and mortality in alcoholic hepatitis patients. In this study, we investigated if faecal cytolysin-positivity can be linked to non-alcoholic fatty liver disease, a highly prevalent disease where new biomarkers and treatment targets are urgently needed. In contrast to what we observed in alcoholic hepatitis, only seven out of 96 non-alcoholic fatty liver disease patients were cytolysin-positive, and these patients did not have increased liver disease activity compared with cytolysin-negative patients. These results indicate that the association of cytolysin carriage with worse clinical outcome might be specific for alcoholic hepatitis.

Hepatocellular carcinoma surveillance with liver imaging is not associated with improved survival.

Objective: International guidelines recommend hepatocellular carcinoma (HCC) surveillance with ultrasound in high-risk patients with chronic liver diseases. However, there is low-strength evidence about the effects on mortality. The aim of our study was to assess the impact of surveillance on the clinical course and survival of HCC patients seen at a tertiary referral center in Germany.Material and methods: We retrospectively evaluated the data of 401 HCC patients, who presented to our clinic between 1997 and 2015. Two groups were compared regarding patient and disease outcomes: one group included patients who received at least two ultrasound examinations for surveillance purposes prior to first diagnosis (n = 111). The other group consisted of patients with HCC at first presentation without foregoing HCC surveillance (n = 290).Results: Median follow-up in the surveillance group was 76 months (range 4-310 months). Patients in the surveillance group had smaller median tumor sizes (3.5 cm vs. 4.5 cm; p < .001), fulfilled more often Milan criteria (64% vs. 42%; p < .001) and received more often liver transplantation (27% vs. 9%, p < .001) when compared with the non-surveillance group. However, HCC surveillance was not associated with an improved survival (14 months in the surveillance group vs. 12 months in the non-surveillance group, p = .375), hazard ratio regarding overall mortality for the surveillance group: 0.80 (95% CI: 0.62-1.04, p = .09).Conclusions: HCC surveillance with ultrasound led to the detection of earlier disease stages but was not significantly associated with improved survival. Further prospective and long-term studies are needed to clarify benefits and harms of HCC surveillance programs on mortality.

Phenotyping non-alcoholic fatty liver disease by the gut microbiota: Ready for prime time?

BACKGROUND AND AIM: Several studies observed alterations in the gut microbiota in patients with non-alcoholic fatty liver disease (NAFLD). However, analyzed patient populations and methods strongly differ among these studies. The aim of this study was to prove the reproducibility of published results and to provide a detailed overview of all findings in our NAFLD cohort using next generation sequencing methods. METHODS: The individual taxonomic microbiota composition of fecal samples from 90 NAFLD patients and 21 healthy controls was analyzed using 16S rRNA gene sequencing. Study participants were grouped according to their disease stage and compared regarding their gut microbiota composition. Studies were identified from PubMed listed publications, and the results were compared with the findings in our cohort. RESULTS: Results from 13 identified studies were compared with our data. A decreased abundance of the Bacteroidetes and Ruminococcaceae as well as an increased abundance of Lactobacillaceae and Veillonellaceae and Dorea were the most frequently reported changes among NAFLD patients in 4/13, 5/13, 4/13, 2/13, and 3/13 studies, respectively. Even though these alterations in the gut microbiota composition were also observed in our patient cohort, the majority of published differences could not be reproduced, neither in our own nor in other NAFLD cohort studies. CONCLUSION: Despite repeatedly reproduced abundance patterns of specific bacteria, the heterogeneous study results did not reveal a consistent disease specific gut microbiota signature. Further prospective studies with homogenous patient cohorts and standardized methods are necessary to phenotype NAFLD by the gut microbiota.

In Vivo Models for Cholangiocarcinoma-What Can We Learn for Human Disease?

Cholangiocarcinoma (CCA) comprises a heterogeneous group of primary liver tumors. They emerge from different hepatic (progenitor) cell populations, typically via sporadic mutations. Chronic biliary inflammation, as seen in primary sclerosing cholangitis (PSC), may trigger CCA development. Although several efforts were made in the last decade to better understand the complex processes of biliary carcinogenesis, it was only recently that new therapeutic advances have been achieved. Animal models are a crucial bridge between in vitro findings on molecular or genetic alterations, pathophysiological understanding, and new therapeutic strategies for the clinic. Nevertheless, it is inherently difficult to recapitulate simultaneously the stromal microenvironment (e.g., immune-competent cells, cholestasis, inflammation, PSC-like changes, fibrosis) and the tumor biology (e.g., mutational burden, local growth, and metastatic spread) in an animal model, so that it would reflect the full clinical reality of CCA. In this review, we highlight available data on animal models for CCA. We discuss if and how these models reflect human disease and whether they can serve as a tool for understanding the pathogenesis, or for predicting a treatment response in patients. In addition, open issues for future developments will be discussed.