Proof of Concept of Telemedicine-Assisted Abdominal Ultrasound Examinations to Improve the Quality of Patient Care in Rural Areas.

(1) Background: Unclear sonographic findings without adequate specialist expertise in abdominal ultrasound (AU) may harm patients in rural areas, due to overlooked diagnoses, unnecessary additional imaging (e.g., CT scan), and/or patient transport to referral expert centers. Appropriate telemedical sonography assistance could lead to corresponding savings. (2) Methods: The study was designed as a randomized trial. Selected study centers performed AU with the best local expertise. Patients were selected and monitored according to the indication that they required AU. The study depicted three basic scenarios. Group 1 corresponds to the telemedically assisted cohort, group 2 corresponds to the non-telemedically assisted cohort, and group 3 corresponds to a telemedically supported cohort for teaching purposes. The target case number of all three groups was 400 patients (20 calculated dropouts included). (3) Discussion: This study might help to clarify whether telemedicine-assisted ultrasound by a qualified expert is non-inferior to presence sonography concerning technical success and whether one of the interventions is superior in terms of efficacy and safety in one or more secondary endpoints. Randomization was provided, as every patient who needed an AU was included and then randomized to one of the groups. The third group consisted of a lower number of patients who were selected from group 1 or 2 for teaching purposes in case of rare diseases or findings. (4) Conclusions: The study investigates whether there are benefits of telemedical ultrasound for patients, medical staff, and the health care system.

Th2 Cell Activation in Chronic Liver Disease Is Driven by Local IL33 and Contributes to IL13-Dependent Fibrogenesis.

BACKGROUND & AIMS: Type 2 immune responses contribute to liver fibrosis in parasite infections, but their role in other liver diseases is less well understood. Here, we aimed at unravelling mechanisms involved in T helper 2 (Th2) T-cell polarization, activation, and recruitment in human liver fibrosis and cirrhosis. METHODS: Tissues, cells, and serum from human livers were analyzed using quantitative reverse-transcription polymerase chain reaction, enzyme-linked immunosorbent assay, fluorescence in situ hybridization, immunostaining, flow cytometry, and various functional in vitro assays. Cellular interactions and soluble mediators involved in T-cell polarization and recruitment were studied, as well as their effect on hepatic stellate cell (HSC) activation, proliferation, and extracellular matrix synthesis. RESULTS: In human liver fibrosis, a stage-dependent increase in Th2-related transcription factors, Th2 cytokines, and trans-acting T-cell-specific transcription factor-expressing T cells was observed, and was highest in cirrhotic livers. The alarmin interleukin (IL)33 was found to be increased in livers and sera from patients with cirrhosis, to act as a chemotactic agent for Th2 cells, and to induce type 2 polarization of CD4+ T cells. Oval cells, liver sinusoidal endothelial cells, intrahepatic macrophages, and migrating monocytes were identified as sources of IL33. IL33-activated T cells, but not IL33 alone, induced HSC activation, as shown by Ki67 and α-smooth muscle actin staining, increased collagen type I alpha 1 chain messenger RNA expression, and wound healing assays. The profibrotic effect of IL33-activated T cells was contact-independent and could be antagonized using monoclonal antibodies against IL13. CONCLUSION: In patients with chronic liver disease, the alarmin IL33 promotes the recruitment and activation of CD4+ T cells with Th2-like properties, which activate paracrine HSC in an IL13-dependent manner and promotes fibrogenesis.

Study protocol of an open-label, single arm phase II trial investigating the efficacy and safety of Trifluridine/Tipiracil combined with irinotecan as a second line therapy in patients with cholangiocarcinoma (TRITICC).

BACKGROUND: The prognosis of patients with advanced biliary tract cancer (BTC) who have progressed on gemcitabine plus cisplatin is dismal. Trifluridine/tipiracil (FTD/TPI) and irinotecan have proven efficacy in different gastrointestinal malignancies. We therefore hypothesized that this combination might improve the therapeutic outcome in patients with BTC after failure of first line treatment. METHODS: TRITICC is an interventional, prospective, open-label, non-randomised, exploratory, multicentre, single-arm phase IIA clinical trial done in 6 sites with expertise in managing biliary tract cancer across Germany. A total of 28 adult patients (aged ≥ 18 years) with histologically verified locally advanced or metastatic biliary tract cancer (including cholangiocarcinoma and gallbladder or ampullary carcinoma) with documented radiological disease progression to first-line gemcitabine based chemotherapy will be included to receive a combination of FTD/TPI plus irinotecan according to previously published protocols. Study treatment will be continued until disease progression according to RECIST 1.1 criteria or occurrence of unacceptable toxicity. The effect of FTD/TPI plus irinotecan on progression-free survival will be analyzed as primary endpoint. Safety (according to NCI-CTCAE), response rates and overall survival are secondary endpoints. In addition, a comprehensive translational research program is part of the study and might provide findings about predictive markers with regard to response, survival periods and resistance to treatment. DISCUSSION: The aim of TRITICC is to evaluate the safety and efficacy of FTD/TPI plus irinotecan in patients with biliary tract cancer refractory to previous Gemcitabine based treatment. TRIAL REGISTRATION: EudraCT 2018-002936-26; NCT04059562.

BISCIT: Biliary interventions in critically ill patients with secondary sclerosing cholangitis-a study protocol for a multicenter, randomized, controlled parallel group trial.

BACKGROUND: Progress of cholangitis to cholangiosepsis is a frequent observation in patients with secondary sclerosing cholangitis in critically ill patients (SSC-CIP). Adequate biliary drainage may reduce episodes of cholangiosepsis and therefore stabilize liver function and improve survival. The primary objective of the BISCIT study is to demonstrate that scheduled biliary interventions will reduce incidence of cholangiosepsis, liver transplantation, or death in patients with SSC-CIP. METHODS: A total of 104 patients will be randomized at ten study sites. Patients with SSC-CIP, confirmed by endoscopic retrograde cholangiography (ERC), will be randomized 1:1 either in the intervention group which will be treated with scheduled biliary interventions (i.e., therapeutic ERC) every 8 weeks for 6 months or in the control group which will receive standard of care. The randomization will be stratified by center. The composite primary efficacy endpoint is defined as (1) occurrence of death, (2) necessity of liver transplantation, or (3) occurrence of cholangiosepsis within 6 months following randomization. DISCUSSION: Prospective evaluation of endoscopic treatment procedures is urgently needed to establish an evidence-based therapeutic treatment algorithm in SSC-CIP. A positive trial result could change the current standard of care for patients with SSC-CIP. The results of this study will be disseminated through presentations at international congresses, workshops, and peer-reviewed publications. TRIAL REGISTRATION: The trial was registered at ClinicalTrials.gov (NCT05396755, date of registration: May 31, 2022, last update: May 31, 2022).

Atezolizumab plus bevacizumab in unresectable hepatocellular carcinoma: Results from a German real-world cohort.

BACKGROUND AND AIMS: Phase III trials have established atezolizumab plus bevacizumab as the novel standard of care for patients with unresectable hepatocellular carcinoma (HCC). However, these trials raised concerns regarding treatment efficacy in non-viral HCC, and it remains unclear whether combination immunotherapy is safe and effective in patients with advanced cirrhosis. METHODS: One hundred patients with unresectable HCC initiated therapy with atezolizumab plus bevacizumab at our centre between January 2020 and March 2022. The control cohort consisted of 80 patients with advanced HCC who received either sorafenib (n = 43) or lenvatinib (n = 37) as systemic treatment. RESULTS: Overall survival (OS) and progression-free survival (PFS) were significantly longer within the atezolizumab/bevacizumab group and comparable to phase III data. The benefits in terms of increased objective response rate (ORR), OS and PFS were consistent across subgroups, including non-viral HCC (58%). The ROC-optimised neutrophil-to-lymphocyte ratio (NLR) cut-off of 3.20 was the strongest independent predictor of ORR and PFS. In patients with advanced cirrhosis Child-Pugh B, liver function was significantly better preserved with immunotherapy. Patients with Child-Pugh B cirrhosis showed similar ORR but shorter OS and PFS compared to patients with preserved liver function. CONCLUSIONS: Atezolizumab plus bevacizumab showed good efficacy and safety in patients with unresectable HCC and partially advanced liver cirrhosis in a real-world setting. Moreover, the NLR was able to predict response to atezolizumab/bevacizumab treatment and may guide patient selection.

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.

NLRP3 activation in neutrophils induces lethal autoinflammation, liver inflammation, and fibrosis.

Sterile inflammation is a central element in liver diseases. The immune response following injurious stimuli involves hepatic infiltration of neutrophils and monocytes. Neutrophils are major effectors of liver inflammation, rapidly recruited to sites of inflammation, and can augment the recruitment of other leukocytes. The NLRP3 inflammasome has been increasingly implicated in severe liver inflammation, fibrosis, and cell death. In this study, the role of NLRP3 activation in neutrophils during liver inflammation and fibrosis was investigated. Mouse models with neutrophil-specific expression of mutant NLRP3 were developed. Mutant mice develop severe liver inflammation and lethal autoinflammation phenocopying mice with a systemic expression of mutant NLRP3. NLRP3 activation in neutrophils leads to a pro-inflammatory cytokine and chemokine profile in the liver, infiltration by neutrophils and macrophages, and an increase in cell death. Furthermore, mutant mice develop liver fibrosis associated with increased expression of pro-fibrogenic genes. Taken together, the present work demonstrates how neutrophils, driven by the NLRP3 inflammasome, coordinate other inflammatory myeloid cells in the liver, and propagate the inflammatory response in the context of inflammation-driven fibrosis.

Inflammatory Cytokines Associated with Diagnosis, Tumor Grade and Prognosis in Patients with Neuroendocrine Tumors.

Background and aims: Inflammatory cytokines represent diagnostic and prognostic biomarkers in manifold cancers. Recent data suggest a pivotal role of these cytokines in different biological processes involved in the development of neuroendocrine tumors (NETs). However, their role as biomarkers in NETs is only poorly understood. Methods: We analyzed serum concentrations of 13 inflammation-related cytokines at different time points in 43 patients with well-differentiated gastroenteropancreatic NETs (G1/G2) treated at Charité Berlin and compared them to 40 healthy controls. The results were correlated with clinical records. Results: Serum concentrations (Median (Interquartile Range (IQR)) in pg/mL) of IL-1ß (124 (82) vs. 68 (61) pg/mL; p = 0.0003), IL-6 (111(122) vs. 88 (32) pg/mL; p = 0.0086), IL-8 (1058 (768) vs. 210 (90) pg/mL; p < 0.0001), IL-18 (2936 (1723) vs. 1590 (704) pg/mL; p < 0.0001), and TNF (271 (260) vs. 42 (25) pg/mL; p < 0.0001) were significantly elevated in NET patients, whereas IL-10 (43 (44) vs. 105 (48) pg/mL; p < 0.0001) showed lower concentrations in NETs when compared to controls. Cytokine levels significantly correlated with tumor grade (IL-6; p = 0.0070), prevalence of distant metastasis (IL-18; p = 0.0313), and disease progression over time (IL-10; p = 0.0033) but not tumor location. Chromogranin A (CgA) and the NETest are currently used to monitor treatment response. A more accurate prediction could possibly be achieved by employing a subset of cytokines. Our data clearly warrants further functional investigation into the role of the immune response and cytokine release in NETs. Conclusion: A biologically plausible panel of cytokines might be added to the diagnostic and prognostic tools currently employed in patients with NETs. Combining different markers into a score would elevate diagnostic accuracy compared to single markers.

Liver Transplantation for Metamizole induced Acute Liver Failure.

Metamizole, or dipyrone, is a frequently prescribed analgetic drug that can cause drug-induced liver injury (DILI). Still, there are only a few metamizole-associated DILI cases (n = 61, including our study) described in the literature. So far liver transplantation has been reported in 6 patients with metamizole-induced acute liver failure. In 2020, a German group described a bigger cohort (n = 23) of metamizole-related DILI. Shortly thereafter, this issue gained wider attention as the German Federal Institute for Drugs and Medical Devices published a Direct Healthcare Professional Communication, emphasizing DILI as a potential adverse event caused by metamizole. We herein report 2 patients that were admitted to our liver transplant center due to acute liver failure (ALF) in April and May 2021. Both patients reported intake of metamizole as pain medication over a few weeks. After ruling out alternative reasons for ALF and fulfilling the King's College criteria both patients received emergency liver transplantations in our center. Pathology assessment of both explants were consistent with metamizole-associated DILI. As illustrated by our 2 cases of metamizole-induced liver failure with subsequent liver transplantation, this rare but presumably often overlooked adverse drug effect of metamizole should be considered as differential diagnosis in cases of cryptogenic liver failure.

Cell-specific Deletion of NLRP3 Inflammasome Identifies Myeloid Cells as Key Drivers of Liver Inflammation and Fibrosis in Murine Steatohepatitis.

BACKGROUND & AIMS: Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease worldwide. The NLRP3 inflammasome, a platform for caspase-1 activation and release of interleukin 1ß, is increasingly recognized in the induction of inflammation and liver fibrosis during NAFLD. However, the cell-specific contribution of NLRP3 inflammasome activation in NAFLD remains unknown. METHODS: To investigate the role of NLRP3 inflammasome activation in hepatocytes, hepatic stellate cells (HSCs) and myeloid cells, a conditional Nlrp3 knock-out mouse was generated and bred to cell-specific Cre mice. Both acute and chronic liver injury models were used: lipopolysaccharide/adenosine-triphosphate to induce in vivo NLRP3 activation, choline-deficient, L-amino acid-defined high-fat diet, and Western-type diet to induce fibrotic nonalcoholic steatohepatitis (NASH). In vitro co-culture studies were performed to dissect the crosstalk between myeloid cells and HSCs. RESULTS: Myeloid-specific deletion of Nlrp3 blunted the systemic and hepatic increase in interleukin 1ß induced by lipopolysaccharide/adenosine-triphosphate injection. In the choline-deficient, L-amino acid-defined high-fat diet model of fibrotic NASH, myeloid-specific Nlrp3 knock-out but not hepatocyte- or HSC-specific knock-out mice showed significant reduction in inflammation independent of steatosis development. Moreover, myeloid-specific Nlrp3 knock-out mice showed ameliorated liver fibrosis and decreased HSC activation. These results were validated in the Western-type diet model. In vitro co-cultured studies with human cell lines demonstrated that HSC can be activated by inflammasome stimulation in monocytes, and this effect was significantly reduced if NLRP3 was downregulated in monocytes. CONCLUSIONS: The study provides new insights in the cell-specific role of NLRP3 in liver inflammation and fibrosis. NLRP3 inflammasome activation in myeloid cells was identified as crucial for the progression of NAFLD to fibrotic NASH. These results may have implications for the development of cell-specific strategies for modulation of NLRP3 activation for treatment of fibrotic NASH.

Shear wave elastography-based liver fibrosis assessment in patients with chronic hepatitis E displays elevated liver stiffness regardless of previous antiviral therapy.

Background: Hepatitis E virus (HEV) infection especially in immunocompromised individuals can lead to chronic hepatitis. Aggressive courses of chronic hepatitis E leading to liver cirrhosis in a short period of time have been described, but evidence on the degree of liver involvement in chronic hepatitis E is rare. We therefore aimed to quantify liver fibrosis in patients with chronic active hepatitis E compared to patients with sustained virological response after ribavirin (RBV) treatment using 2D-shear wave elastography (2D-SWE) to measure liver stiffness. Methods: Patients with chronic hepatitis E underwent 2D-SWE, B-mode and Doppler ultrasound and laboratory testing in order to assess severity of liver involvement. Results: In this cross-sectional study, we included 14 patients of whom 8 had ongoing chronic hepatitis E and 6 patients had been successfully treated for chronic hepatitis E. The most frequent cause for immunosuppression was prior kidney transplantation (n=12), one patient was a multivisceral transplant recipient, one had been treated for lymphoma. Five patients cleared HEV after RBV therapy, one patient reached viral clearance after reduction of his immunosuppressive medication. Using 2D-SWE measurement, 71.4% displayed increased stiffness indicative of liver fibrosis: 57.1% classified as significant fibrosis and 14.3% as severe fibrosis. Liver stiffness did not differ between patients with active chronic hepatitis E and in patients who had cleared HEV (1.59 and 1.54 m/s respectively). Compared with a control group of kidney transplant recipients without hepatitis E (1.44 m/s), the patients with a history of hepatitis E displayed a significantly higher liver stiffness (P=0.04). Conclusions: In our cohort of chronic hepatitis E patients, elevated liver stiffness indicating liver fibrosis was common and significantly higher than in controls. This is consistent with prior sparse reports of the presence of liver fibrosis or cirrhosis in chronic hepatitis E and emphasizes the need for HEV testing, therapy and research on new therapeutic options. As elevated liver stiffness was also present in patients after HEV treatment, continuous liver surveillance including elastography and ultrasound should be considered.

Shear wave elastography and shear wave dispersion imaging in primary biliary cholangitis-a pilot study.

BACKGROUND: Primary biliary cholangitis (PBC) is a chronic liver disease that can lead to liver fibrosis and cirrhosis. Two-dimensional shear wave elastography (2D-SWE) is a modern technique for fibrosis assessment. However, data regarding its performance in PBC is sparse. We aimed to characterize severity of liver disease in PBC patients using non-invasive 2D-SWE and the new methods of attenuation imaging (ATI) and shear wave dispersion imaging (SWD). METHODS: Twenty two PBC patients were examined with 2D-SWE, SWD and ATI, alongside established non-invasive fibrosis and steatosis assessment methods as well as liver function tests. RESULTS: Median 2D-SWE values were 1.48 m/s (range, 1.14-2.13 m/s) and 6.7 kPa (range, 3.8-14.7 kPa), respectively. Median SWD, ATI, transient elastography (TE) and controlled attenuation parameter (CAP) values were 13.9 m/s/kHz (range, 11.6-21 m/s/kHz), 0.57 dB/cm/MHz (range, 0.5-0.68 dB/cm/MHz), 7 kPa (range, 3.7-14.6 kPa), and 208 dB/m (range, 107-276 dB/m), respectively. 2D-SWE displayed a significant correlation with spleen length, platelet count, non-invasive fibrosis scores (FIB-4, APRI) and with TE. SWD correlated with alkaline phosphatase (ALP) levels, which is a prognostic marker in PBC. CONCLUSIONS: Our findings add further evidence that 2D-SWE is a reliable method for fibrosis assessment in PBC. Even though the cohort size was small, the correlation of SWD with the prognostic marker ALP suggests a potentially valuable role of this new non-invasive method in evaluating liver disease activity in PBC.

NOD-like receptor protein 3 activation causes spontaneous inflammation and fibrosis that mimics human NASH.

BACKGROUND AND AIMS: The NOD-like receptor protein 3 (NLRP3) inflammasome is a central contributor to human acute and chronic liver disease, yet the molecular and cellular mechanisms by which its activation precipitates injury remain incompletely understood. Here, we present single cell transcriptomic profiling of livers from a global transgenic tamoxifen-inducible constitutively activated Nlrp3A350V mutant mouse, and we investigate the changes in parenchymal and nonparenchymal liver cell gene expression that accompany inflammation and fibrosis. APPROACH AND RESULTS: Our results demonstrate that NLRP3 activation causes chronic extramedullary myelopoiesis marked by myeloid progenitors that differentiate into proinflammatory neutrophils, monocytes, and monocyte-derived macrophages. We observed prominent neutrophil infiltrates with increased Ly6gHI and Ly6gINT cells exhibiting transcriptomic signatures of granulopoiesis typically found in the bone marrow. This was accompanied by a marked increase in Ly6cHI monocytes differentiating into monocyte-derived macrophages that express transcriptional programs similar to macrophages of NASH models. NLRP3 activation also down-regulated metabolic pathways in hepatocytes and shifted hepatic stellate cells toward an activated profibrotic state based on expression of collagen and extracellular matrix regulatory genes. CONCLUSIONS: These results define the single cell transcriptomes underlying hepatic inflammation and fibrosis precipitated by NLRP3 activation. Clinically, our data support the notion that NLRP3-induced mechanisms should be explored as therapeutic target in NASH-like inflammation.

Pyroptosis in Steatohepatitis and Liver Diseases.

Pyroptosis is an inflammatory form of regulated cell death, which functions in the clearance of intracellularly replicating pathogens by cell lysis in order to induce further immune response. Since the discovery of the gasdermin (GSDM) family, pyroptosis has attracted attention in a wide range of inflammatory diseases such as nonalcoholic steatohepatitis and other liver diseases. Due to the cleavage of GSDMs by different caspases, the amino-terminal GSDM fragments form membrane pores essential for pyroptosis that facilitate the release of inflammatory cytokines by loss of ionic gradient and membrane rupture. In this review, we address the key molecular and cellular processes that induce pyroptosis in the liver and its significance in the pathogenesis of common liver diseases in different human and experimental mice studies.

Bile Acids Activate NLRP3 Inflammasome, Promoting Murine Liver Inflammation or Fibrosis in a Cell Type-Specific Manner.

Bile acids (BA) as important signaling molecules are considered crucial in development of cholestatic liver injury, but there is limited understanding on the involved cell types and signaling pathways. The aim of this study was to evaluate the inflammatory and fibrotic potential of key BA and the role of distinct liver cell subsets focusing on the NLRP3 inflammasome. C57BL/6 wild-type (WT) and Nlrp3-/- mice were fed with a diet supplemented with cholic (CA), deoxycholic (DCA) or lithocholic acid (LCA) for 7 days. Additionally, primary hepatocytes, Kupffer cells (KC) and hepatic stellate cells (HSC) from WT and Nlrp3-/- mice were stimulated with aforementioned BA ex vivo. LCA feeding led to strong liver damage and activation of NLRP3 inflammasome. Ex vivo KC were the most affected cells by LCA, resulting in a pro-inflammatory phenotype. Liver damage and primary KC activation was both ameliorated in Nlrp3-deficient mice or cells. DCA feeding induced fibrotic alterations. Primary HSC upregulated the NLRP3 inflammasome and early fibrotic markers when stimulated with DCA, but not LCA. Pro-fibrogenic signals in liver and primary HSC were attenuated in Nlrp3-/- mice or cells. The data shows that distinct BA induce NLRP3 inflammasome activation in HSC or KC, promoting fibrosis or inflammation.

The Role of miRNA in the Pathophysiology of Neuroendocrine Tumors.

Neuroendocrine tumors (NETs) represent a tumor group that is both rare and heterogeneous. Prognosis is largely determined by the tumor grading and the site of the primary tumor and metastases. Despite intensive research efforts, only modest advances in diagnostic and therapeutic approaches have been achieved in recent years. For patients with non-respectable tumor stages, prognosis is poor. In this context, the development of novel diagnostic tools for early detection of NETs and prediction of tumor response to therapy as well as estimation of the overall prognosis would greatly improve the clinical management of NETs. However, identification of novel diagnostic molecules is hampered by an inadequate understanding of the pathophysiology of neuroendocrine malignancies. It has recently been demonstrated that microRNA (miRNA), a family of small RNA molecules with an established role in the pathophysiology of quite different cancer entities, may also play a role as a biomarker. Here, we summarize the available knowledge on the role of miRNAs in the development of NET and highlight their potential use as serum-based biomarkers in the context of this disease. We discuss important challenges currently preventing their use in clinical routine and give an outlook on future directions of miRNA research in NET.

The Role of Microbiota in Primary Sclerosing Cholangitis and Related Biliary Malignancies.

Primary sclerosing cholangitis (PSC) is an immune-related cholangiopathy characterized by biliary inflammation, cholestasis, and multifocal bile duct strictures. It is associated with high rates of progression to end-stage liver disease as well as a significant risk of cholangiocarcinoma (CCA), gallbladder cancer, and colorectal carcinoma. Currently, no effective medical treatment with an impact on the overall survival is available, and liver transplantation is the only curative treatment option. Emerging evidence indicates that gut microbiota is associated with disease pathogenesis. Several studies analyzing fecal and mucosal samples demonstrate a distinct gut microbiome in individuals with PSC compared to healthy controls and individuals with inflammatory bowel disease (IBD) without PSC. Experimental mouse and observational human data suggest that a diverse set of microbial functions may be relevant, including microbial metabolites and bacterial processing of pharmacological agents, bile acids, or dietary compounds, altogether driving the intrahepatic inflammation. Despite critical progress in this field over the past years, further functional characterization of the role of the microbiota in PSC and related malignancies is needed. In this review, we discuss the available data on the role of the gut microbiome and elucidate important insights into underlying pathogenic mechanisms and possible microbe-altering interventions.