The Pathogenesis of Autoimmune Liver Disease

Inflammasome Molecular Insights in Autoimmune Diseases

Autoimmune diseases (AIDs) emerge due to an irregular immune response towards self- and non-self-antigens. Inflammation commonly accompanies these conditions, with inflammatory factors and inflammasomes playing pivotal roles in their progression. Key concepts in molecular biology, inflammation, and molecular mimicry are crucial to understanding AID development. Exposure to foreign antigens can cause inflammation, potentially leading to AIDs through molecular mimicry triggered by cross-reactive epitopes. Molecular mimicry emerges as a key mechanism by which infectious or chemical agents trigger autoimmunity. In certain susceptible individuals, autoreactive T or B cells may be activated by a foreign antigen due to resemblances between foreign and self-peptides. Chronic inflammation, typically driven by abnormal immune responses, is strongly associated with AID pathogenesis. Inflammasomes, which are vital cytosolic multiprotein complexes assembled in response to infections and stress, are crucial to activating inflammatory processes in macrophages. Chronic inflammation, characterized by prolonged tissue injury and repair cycles, can significantly damage tissues, thereby increasing the risk of AIDs. Inhibiting inflammasomes, particularly in autoinflammatory disorders, has garnered significant interest, with pharmaceutical advancements targeting cytokines and inflammasomes showing promise in AID management.

Fecal microbiota transplantation in autoimmune diseases - An extensive paper on a pathogenetic therapy

The role of infections in the pathogenesis of autoimmune diseases has long been recognized and reported. In addition to infectious agents, the internal composition of the "friendly" living bacteria, (microbiome) and its correlation to immune balance and dysregulation have drawn the attention of researchers for decades. Nevertheless, only recently, scientific papers regarding the potential role of transferring microbiome from healthy donor subjects to patients with autoimmune diseases has been proposed. Fecal microbiota transplantation or FMT, carries the logic of transferring microorganisms responsible for immune balance from healthy donors to individuals with immune dysregulation or more accurately for our paper, autoimmune diseases. Viewing the microbiome as a pathogenetic player allows us to consider FMT as a pathogenetic-based treatment. Promising results alongside improved outcomes have been demonstrated in patients with different autoimmune diseases following FMT. Therefore, in our current extensive review, we aimed to highlight the implication of FMT in various autoimmune diseases, such as inflammatory bowel disease, autoimmune thyroid and liver diseases, systemic lupus erythematosus, and type 1 diabetes mellitus, among others. Presenting all the aspects of FMT in more than 12 autoimmune diseases in one paper, to the best of our knowledge, is the first time presented in medical literature. Viewing FMT as such could contribute to better understanding and newer application of the model in the therapy of autoimmune diseases, indeed.

Liver fibrosis in NAFLD/NASH: from pathophysiology towards diagnostic and therapeutic strategies

Liver fibrosis, as an excess deposition of extracellular matrix (ECM) components, results from chronic liver injury as well as persistent activation of inflammatory response and of fibrogenesis. Liver fibrosis is a major determinant for chronic liver disease (CLD) progression and in the last two decades our understanding on the major molecular and cellular mechanisms underlying the fibrogenic progression of CLD has dramatically improved, boosting pre-clinical studies and clinical trials designed to find novel therapeutic approaches. From these studies several critical concepts have emerged, starting to reveal the complexity of the pro-fibrotic microenvironment which involves very complex, dynamic and interrelated interactions between different hepatic and extrahepatic cell populations. This review will offer first a recapitulation of established and novel pathophysiological basic principles and concepts by intentionally focus the attention on NAFLD/NASH, a metabolic-related form of CLD with a high impact on the general population and emerging as a leading cause of CLD worldwide. NAFLD/NASH-related pro-inflammatory and profibrogenic mechanisms will be analysed as well as novel information on cells, mediators and signalling pathways which have taken advantage from novel methodological approaches and techniques (single cell genomics, imaging mass cytometry, novel in vitro two- and three-dimensional models, etc.). We will next offer an overview on recent advancement in diagnostic and prognostic tools, including serum biomarkers and polygenic scores, to support the analysis of liver biopsies. Finally, this review will provide an analysis of current and emerging therapies for the treatment of NAFLD/NASH patients.

A Novel Synbiotic Alleviates Autoimmune Hepatitis by Modulating the Gut Microbiota-Liver Axis and Inhibiting the Hepatic TLR4/NF-κB/NLRP3 Signaling Pathway

Autoimmune hepatitis (AIH) is a liver disease characterized by chronic liver inflammation. The intestinal barrier and microbiome play critical roles in AIH progression. AIH treatment remains challenging because first-line drugs have limited efficacy and many side effects. Thus, there is growing interest in developing synbiotic therapies. This study investigated the effects of a novel synbiotic in an AIH mouse model. We found that this synbiotic (Syn) ameliorated liver injury and improved liver function by reducing hepatic inflammation and pyroptosis. The Syn reversed gut dysbiosis, as indicated by an increase in beneficial bacteria (e.g., Rikenella and Alistipes) and a decrease in potentially harmful bacteria (e.g., Escherichia-Shigella) and lipopolysaccharide (LPS)-bearing Gram-negative bacterial levels. The Syn maintained intestinal barrier integrity, reduced LPS, and inhibited the TLR4/NF-κB and NLRP3/Caspase-1 signaling pathway. In addition, microbiome phenotype prediction by BugBase and bacterial functional potential prediction using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) showed that Syn improved gut microbiota function involving inflammatory injury, metabolism, immune response, and pathopoiesia. Furthermore, the new Syn was as effective as prednisone against AIH. Therefore, this novel Syn could be a candidate drug for alleviating AIH through its anti-inflammatory and antipyroptosis properties that relieve endothelial dysfunction and gut dysbiosis. IMPORTANCE Synbiotics can ameliorate liver injury and improve liver function by reducing hepatic inflammation and pyroptosis. Our data indicate that our new Syn not only reverses gut dysbiosis by increasing beneficial bacteria and decreasing lipopolysaccharide (LPS)-bearing Gram-negative bacteria but also maintains intestinal barrier integrity. Thus, its mechanism might be associated with modulating gut microbiota composition and intestinal barrier function by inhibiting the TLR4/NF-κB/NLRP3/pyroptosis signaling pathway in the liver. This Syn is as effective as prednisone in treating AIH without side effects. Based on these findings, this novel Syn represents a potential therapeutic agent for AIH in clinical practice.

Dietary Polyphenols Alleviate Autoimmune Liver Disease by Mediating the Intestinal Microenvironment: Challenges and Hopes

Autoimmune liver disease is a chronic liver disease caused by an overactive immune response in the liver that imposes a significant health and economic cost on society. Due to the side effects of existing medicinal medications, there is a trend toward seeking natural bioactive compounds as dietary supplements. Currently, dietary polyphenols have been proven to have the ability to mediate gut-liver immunity and control autoimmune liver disease through modulating the intestinal microenvironment. Based on the preceding, this Review covers the many forms of autoimmune liver illnesses, their pathophysiology, and the modulatory effects of polyphenols on immune disorders. Finally, we focus on how polyphenols interact with the intestinal milieu to improve autoimmune liver disease. In conclusion, we suggest that dietary polyphenols have the potential as gut-targeted modulators for the prevention and treatment of autoimmune liver disease and highlight new perspectives and critical issues for future pharmacological applications.

Ginsenosides Regulates Innate Immunity to Affect Immune Microenvironment of AIH Through Hippo-YAP/TAZ Signaling Pathway

Autoimmune hepatitis (AIH) is characterized by chronic progressive liver inflammatory, but there is still no safe and effective medicine. Therefore, glucocorticoid remains the top choice for AIH treatment. In previous studies, it has been confirmed that ginsenosides (GSS) can produce glucocorticoid-like effects and therapeutic effects on various autoimmune diseases. However, the mechanism of GSS for AIH remains unclear. As an important part of the innate immune system, bone marrow-derived suppressor cells (MDSC) have been identified as an important driver of follow-up acquired immune response in many autoimmune diseases, including AIH. Herein, it was found out that GSS intervention can be effective in regulating the immune microenvironment and liver impairment induced by Con A in AIH mice. In vitro, the MDSCs derived from healthy mice and the T cells deried from AIH mice were co-cultured. Then, different drugs were intervened with to explore the therapeutic mechanism. Besides, the proliferation and differentiation of MDSCs and T cells were analyzed by flow cytometry, while GR, Hippo-YAP signal pathway and the expression of MDSC-related genes and proteins were detected through qRT-PCR and Western Blot. The changes in NO and ROS levels were further analyzed. The trend of related cytokines expression (IFN- γ, TGF- β, IL-10, IL-6, IL-17) was detected by ELISA. Furthermore, an analysis was conducted as to the ALT and liver pathology of mice for evaluating the liver function of mice. It was discovered that MDSCs proliferation was inhibited, and that T cells tended to differentiate into Th17 rather than Treg in AIH mice. Moreover, the intervention of GSS activated GR and Yap, in addition to promoting the proliferation of MDSCs, especially M-MDSCs. This further promoted the differentiation of Treg to enable immune tolerance, thus alleviating liver impairment. Therefore, it was proposed that GSS can alleviate AIH by modulating the innate immunity and adaptive T cell immunity, which may be the underlying mechanism for GSS to mitigate the liver impairment induced by AIH.

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.

The Microbiome in Autoimmune Liver Diseases: Metagenomic and Metabolomic Changes

Recent studies have identified the critical role of microbiota in the pathophysiology of autoimmune liver diseases (AILDs), including autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC). Metagenomic studies reveal significant decrease of gut bacterial diversity in AILDs. Although profiles of metagenomic vary widely, Veillonella is commonly enriched in AIH, PBC, and PSC. Apart from gut microbiome, the oral and bile microbiome seem to be associated with these diseases as well. The functional analysis of metagenomics suggests that metabolic pathways changed in the gut microbiome of the patients. Microbial metabolites, including short-chain fatty acids (SCFAs) and microbial bile acid metabolites, have been shown to modulate innate immunity, adaptive immunity, and inflammation. Taken together, the evidence of host–microbiome interactions and in-depth mechanistic studies needs further accumulation, which will offer more possibilities to clarify the mechanisms of AILDs and provide potential molecular targets for the prevention and treatment in the future.

Familiarity Breeds Strategy: In Silico Untangling of the Molecular Complexity on Course of Autoimmune Liver Disease-to-Hepatocellular Carcinoma Transition Predicts Novel Transcriptional Signatures

Autoimmune liver diseases (AILD) often lead to transformation of the liver tissues into hepatocellular carcinoma (HCC). Considering the drawbacks of surgical procedures in such cases, need of successful non-invasive therapeutic strategies and treatment modalities for AILD-associated-HCC still exists. Due to the lack of clear, sufficient knowledge about factors mediating AILD-to-HCC transition, an in silico approach was adopted to delineate the underlying molecular deterministic factors. Parallel enrichment analyses on two different public microarray datasets (GSE159676 and GSE62232) pinpointed the core transcriptional regulators as key players. Correlation between the expression kinetics of these transcriptional modules in AILD and HCC was found to be positive primarily with the advancement of hepatic fibrosis. Most of the regulatory interactions were operative during early (F0-F1) and intermediate fibrotic stages (F2-F3), while the extent of activity in the regulatory network considerably diminished at late stage of fibrosis/cirrhosis (F4). Additionally, most of the transcriptional targets with higher degrees of connectivity in the regulatory network (namely DCAF11, PKM2, DGAT2 and BCAT1) may be considered as potential candidates for biomarkers or clinical targets compared to their low-connectivity counterparts. In summary, this study uncovers new possibilities in the designing of novel prognostic and therapeutic regimen for autoimmunity-associated malignancy of liver in a disease progression-dependent fashion.

The significance of cytoplasmic antinuclear antibody patterns in autoimmune liver disease

We aimed to determine the significance of cytoplasmic antinuclear antibody (ANA) patterns using computer-aided immunofluorescence microscopy in patients with autoimmune liver diseases (AILD). ANA staining pattern was identified by treating cultured human epithelial type 2 (HEp-2) cells with the sera of the patients. Medical records of patients with suspected AILD who had positive cytoplasmic ANA patterns between February 2017 and November 2019 were retrospectively reviewed for clinical, laboratory, and immunological data. Cytoplasmic ANA patterns of AILD and non-AILD groups were compared. Further subgroup analysis of patients with AILD who had reticular or speckled cytoplasmic ANA patterns was conducted. We found that among the 196 patients with positive cytoplasmic ANA patterns, 113 (57.6%) were diagnosed with AILD. The percentage of reticular cytoplasmic pattern was higher in the AILD group than that in the non-AILD group (64.0% vs. 21.9%, p < 0.001). Furthermore, patients with AILD who exhibited a reticular ANA pattern demonstrated a higher positive rate for anti-mitochondrial antibodies (66.7% vs. 2.6%, p < 0.001) than those who exhibited the speckled ANA pattern. Moreover, AILD patients with the reticular ANA pattern displayed a lower positive rate for anti-smooth muscle antibodies (0% vs. 45%, p < 0.001) and nuclear ANA pattern (73.2% vs. 97.5%, p = 0.003) than those with the speckled ANA pattern. Therefore, cytoplasmic ANA patterns could be used to guide AILD characterization in suspected AILD cases, especially as the reticular ANA pattern is strongly associated with AILD. Thus, it is important to check cytoplasmic ANA patterns for AILD evaluation, even when nuclear ANA patterns are negative.

Cellular therapies for the treatment of immune-mediated GI and liver disease

INTRODUCTION

Immune-mediated liver and gastrointestinal diseases are chronic conditions that lack curative treatments. Despite advances in the understanding and treatment of these conditions, they frequently remain refractory to treatment and represent a significant unmet need. Cellular therapies are an emerging option and hold the potential to have a major impact.

DATA SOURCES

A literature review was carried out using Pubmed. Keywords used for search were 'ATMP', 'immune mediated', 'autoimmune liver disease' and 'immune mediated gastrointestinal conditions', 'cell therapy', 'MSC', 'HSCT', 'Regulatory T cells', 'GVHD', 'Coeliac disease' 'IBD', 'PSC', 'AIH', 'PBC'. No new data were generated or analysed in support of this review.

AREAS OF AGREEMENT

There is substantial evidence from clinical trials to support the use of cell therapies as a treatment for immune-mediated liver and gastrointestinal conditions. Cellular therapy products have the ability to 'reset' the dysregulated immune system and this in turn can offer a longer term remission. There are ongoing clinical trials with mesenchymal stromal cells (MSCs) and other cells to evidence their efficacy profile and fill the gaps in current knowledge. Insights gained will inform future trial designs and subsequent therapeutic applications.

AREAS OF CONTROVERSY

There remains some uncertainty around the extrapolation of results from animal studies to clinical trials. Longevity of the therapeutic effects seen after the use of cell therapy needs to be scrutinized further. Heterogeneity in the selection of cells, source, methods of productions and cell administration pose challenges to the interpretation of the data.

GROWING POINTS

MSCs are emerging as a key therapeutic cells in immune-mediated liver and gastrointestinal conditions. Ongoing trials with these cells will provide new insights and a better understanding thus informing future larger scale studies.

AREAS TIMELY FOR DEVELOPING RESEARCH

Larger scale clinical trials to build on the evidence from small studies regarding safety and efficacy of cellular therapy are still needed before cellular therapies can become off the shelf treatments. Alignment of academia and industry to standardize the processes involved in cell selection, manipulation and expansion and subsequent use in clinical trials is an important avenue to explore further.

Intrahepatic biliary strictures after liver transplantation are morphologically similar to primary sclerosing cholangitis but immunologically distinct

OBJECTIVE

Biliary strictures are an important cause of morbidity and mortality in primary hepatic disease and after liver transplantation (LT). We aimed to characterize inflammatory cytokines in biliary fluids in biliary strictures to investigate their immunological origin.

METHODS

We conducted a retrospective study on 72 patients with strictures after LT, eight patients with primary sclerosing cholangitis (PSC) and 15 patients with secondary sclerosing cholangitis (SSC). We measured cytokines interleukin (IL)-2, -4, -6, -10, -17, monocyte chemoattractant protein (MCP)-1, fibroblast growth factor (FGF)-2 and interferon (IFN)-γ as well as biochemical components such as protein and phospholipids in biliary fluid obtained from endoscopic retrograde cholangiography (ERC). Cell viability assays were performed on human cholangiocytes (H69) after being treated with IL-6, IL-4 and IFN-γ.

RESULTS

Bile of patients with diffuse strictures after LT or due to SSC showed low values of all measured cytokines except for IL-6 levels, which were largely elevated in patients with diffuse strictures after LT. Patients high in biliary IL-6 showed an increase in profibrotic markers FGF-2 and MCP-1. In contrast, PSC bile was dominated by a Th1/Th17 profile with elevated IL-2, IL-17 and IFN-γ. In LT patients with biliary strictures, biliary IL-6 negatively predicted retransplantation-free survival after ERC.

CONCLUSION

PSC patients showed a biliary Th1/Th17 cytokine profile, while SSC and diffuse strictures showed low values of cytokines except IL-6. In diffuse intrahepatic strictures after LT, biliary IL-6 is strongly associated with retransplantation-free survival after ERC.

Ubiquitin-Like Post-Translational Modifications (Ubl-PTMs): Small Peptides with Huge Impact in Liver Fibrosis

Liver fibrosis is characterized by the excessive deposition of extracellular matrix proteins including collagen that occurs in most types of chronic liver disease. Even though our knowledge of the cellular and molecular mechanisms of liver fibrosis has deeply improved in the last years, therapeutic approaches for liver fibrosis remain limited. Profiling and characterization of the post-translational modifications (PTMs) of proteins, and more specifically NEDDylation and SUMOylation ubiquitin-like (Ubls) modifications, can provide a better understanding of the liver fibrosis pathology as well as novel and more effective therapeutic approaches. On this basis, in the last years, several studies have described how changes in the intermediates of the Ubl cascades are altered during liver fibrosis and how specific targeting of particular enzymes mediating these ubiquitin-like modifications can improve liver fibrosis, mainly in in vitro models of hepatic stellate cells, the main fibrogenic cell type, and in pre-clinical mouse models of liver fibrosis. The development of novel inhibitors of the Ubl modifications as well as novel strategies to assess the modified proteome can provide new insights into the overall role of Ubl modifications in liver fibrosis.

Association of Autoimmune Hepatitis and Cardiovascular Disease

BACKGROUND

Autoimmune Hepatitis is a chronic liver disease while Cardiovascular Disease is seen in inflammatory states. This study sought to determine if Cardiovascular Disease was associated with Autoimmune Hepatitis.

METHODS

The National Inpatient Sample selected patients with a primary diagnosis of Autoimmune Hepatitis and secondary diagnosis of Cardiovascular Disease in 2014. The primary outcome was the association of Autoimmune Hepatitis with Cardiovascular Disease. Secondary outcomes evaluated the hospital burden with Cardiovascular Disease.

RESULTS

16,375 patients with Autoimmune Hepatitis were included in the study. There was a decreased association between Autoimmune Hepatitis and Cardiovascular Disease (aOR 0.77, 95% CI 0.69-0.85, p < 0.00), Coronary Artery Disease, (aOR 0.75, 95% CI 0.67-0.85, p < 0.00), and Peripheral Vascular Disease (aOR 0.75, 95% CI 0.60-0.93, p = 0.01). Moreover, Coronary Artery Disease comprises 84% of the overall Cardiovascular Disease cohort and did not demonstrate significantly increased length of stay (aOR -0.53, 95% CI -1.16 to 0.12, p = 0.11) or hospitalization cost (aOR -6711, 95% CI -14336 to 912, p = 0.08).

DISCUSSION

The decreased association between Autoimmune Hepatitis and Cardiovascular Disease is likely multifactorial in etiology. Consequently, this observation requires further examination with prospective trials.

Gut Microbiota and IL-17A: Physiological and Pathological Responses

IL-17A is a cytokine which is produced by several immune and non-immune cells. The cytokine plays dual roles from protection from microbes and protection from pro-inflammatory based diseases to induction of the pro-inflammatory based diseases. The main mechanisms which lead to the controversial roles of IL-17A are yet to be clarified. Gut microbiota (GM) are the resident probiotic bacteria in the gastrointestinal tracts which have been introduced as a plausible regulator of IL-17A production and functions. This review article describes the recent information regarding the roles played by GM in determination of IL-17A functions outcome.

ERK Pathway in Activated, Myofibroblast-Like, Hepatic Stellate Cells: A Critical Signaling Crossroad Sustaining Liver Fibrosis. Int J Mol Sci. 2019;20. [PMID: 31159366 PMCID: PMC6600376 DOI: 10.3390/ijms20112700]

Fibrogenic progression of chronic liver disease, whatever the etiology, is characterized by persistent chronic parenchymal injury, chronic activation of inflammatory response, and sustained activation of liver fibrogenesis, and of pathological wound healing response. A critical role in liver fibrogenesis is played by hepatic myofibroblasts (MFs), a heterogeneous population of α smooth-muscle actin—positive cells that originate from various precursor cells through a process of activation and transdifferentiation. In this review, we focus the attention on the role of extracellular signal-regulated kinase (ERK) signaling pathway as a critical one in modulating selected profibrogenic phenotypic responses operated by liver MFs. We will also analyze major therapeutic antifibrotic strategies developed in the last two decades in preclinical studies, some translated to clinical conditions, designed to interfere directly or indirectly with the Ras/Raf/MEK/ERK signaling pathway in activated hepatic MFs, but that also significantly increased our knowledge on the biology and pathobiology of these fascinating profibrogenic cells.

The Antidepressant Mirtazapine Inhibits Hepatic Innate Immune Networks to Attenuate Immune-Mediated Liver Injury in Mice

Activation of the innate immune system, including tissue macrophages and associated neutrophil infiltration, is an important driver of subsequent adaptive immune responses in many autoimmune diseases, including autoimmune hepatitis (AIH). The antidepressant mirtazapine has a unique complex pharmacology, altering signaling through a number of serotonin and histamine receptors that can impact macrophage function; an effect potentially influencing AIH outcome. In the mouse model of concanavalin A (Con A) induced liver injury (mimics many aspects of human AIH), in which early innate immune activation (i.e., stimulated hepatic macrophages/monocytes recruit neutrophils and additional monocytes to the liver) critically drives immune-mediated hepatitis induction, mirtazapine strikingly and dose-dependently inhibited Con A-induced liver injury. This inflammation-suppressing effect of mirtazapine was linked to an attenuation of Con A-stimulated early innate immune responses within the liver, including inhibition of hepatic macrophage/monocyte activation, decreased hepatic macrophage/monocyte-derived pro-inflammatory cytokine (e.g., TNFα) and chemokine (e.g., CXCL1 and CXCL2) production, suppression of Con A-induced increases in the hepatic expression of the neutrophil relevant endothelial cell adhesion molecule ICAM-1, with the resultant significant reduction in neutrophil recruitment into the liver. Consistent with our findings in the Con A model, mirtazapine also significantly reduced activation-induced release of cytokine/chemokine mediators from human CD14⁺ monocytes in vitro. Conclusion: Our data suggest that mirtazapine can attenuate hepatic innate immune responses that critically regulate the subsequent development of autoimmune liver injury. Therefore, given that it is a safe and widely used medication, mirtazapine may represent a novel therapeutic approach to autoimmune liver disease.

Diagnosis and Management of Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a chronic, cholestatic, autoimmune disease with a variable progressive course. PBC can cause debilitating symptoms including fatigue and pruritus and, if left untreated, is associated with a high risk of cirrhosis and related complications, liver failure, and death. Recent changes to the PBC landscape include a name change, updated guidelines for diagnosis and treatment as well as new treatment options that have recently become available. Practicing clinicians face many unanswered questions when managing PBC. To assist these healthcare providers in managing patients with PBC, the American College of Gastroenterology (ACG) Institute for Clinical Research & Education, in collaboration with the Chronic Liver Disease Foundation (CLDF), organized a panel of experts to evaluate and summarize the most current and relevant peer-reviewed literature regarding PBC. This, combined with the extensive experience and clinical expertise of this expert panel, led to the formation of this clinical guidance on the diagnosis and management of PBC.

Liver fibrosis: Pathophysiology, pathogenetic targets and clinical issues. Mol Aspects Med. 2019;65:37-55. [PMID: 30213667 DOI: 10.1016/j.mam.2018.09.002]

The progression of chronic liver diseases (CLD), irrespective of etiology, involves chronic parenchymal injury, persistent activation of inflammatory response as well as sustained activation of liver fibrogenesis and wound healing response. Liver fibrogenesis, is a dynamic, highly integrated molecular, cellular and tissue process responsible for driving the excess accumulation of extracellular matrix (ECM) components (i.e., liver fibrosis) sustained by an eterogeneous population of hepatic myofibroblasts (MFs). The process of liver fibrogenesis recognizes a number of common and etiology-independent mechanisms and events but it is also significantly influenced by the specific etiology, as also reflected by peculiar morphological patterns of liver fibrosis development. In this review we will analyze the most relevant established and/or emerging pathophysiological issues underlying CLD progression with a focus on the role of critical hepatic cell populations, mechanisms and signaling pathways involved, as they represent potential therapeutic targets, to finally analyze selected and relevant clinical issues.

Potential triggering factors of acute liver failure as a first manifestation of autoimmune hepatitis-a single center experience of 52 adult patients

AIM

To investigate potential triggering factors leading to acute liver failure (ALF) as the initial presentation of autoimmune hepatitis (AIH).

METHODS

A total of 565 patients treated at our Department between 2005 and 2017 for histologically-proven AIH were retrospectively analyzed. However, 52 patients (9.2%) fulfilled the criteria for ALF defined by the "American Association for the Study of the Liver (AASLD)". According to this definition, patients with "acute-on-chronic" or "acute-on-cirrhosis" liver failure were excluded. Following parameters with focus on potential triggering factors were evaluated: Patients' demographics, causation of liver failure, laboratory data (liver enzymes, MELD-score, autoimmune markers, virus serology), liver histology, immunosuppressive regime, and finally, outcome of our patients.

RESULTS

The majority of patients with ALF were female (84.6%) and mean age was 43.6 ± 14.9 years. Interestingly, none of the patients with ALF was positive for anti-liver kidney microsomal antibody (LKM). We could identify potential triggering factors in 26/52 (50.0%) of previously healthy patients presenting ALF as their first manifestation of AIH. These were drug-induced ALF (57.7%), virus-induced ALF (30.8%), and preceding surgery in general anesthesia (11.5%), respectively. Unfortunately, 6 out of 52 patients (11.5%) did not survive ALF and 3 patients (5.7%) underwent liver transplantation (LT). Comparing data of survivors and patients with non-recovery following treatment, MELD-score (P < 0.001), age (P < 0.05), creatinine (P < 0.01), and finally, ALT-values (P < 0.05) reached statistical significance.

CONCLUSION

Drugs, viral infections, and previous surgery may trigger ALF as the initial presentation of AIH. Advanced age and high MELD-score were associated with lethal outcome.

Pathophysiology of liver fibrosis and the methodological barriers to the development of anti-fibrogenic agents

Liver fibrosis and cirrhosis resulting from long-standing liver damage represents a major health care burden worldwide. To date, there is no anti-fibrogenic agent available, making liver transplantation the only curative treatment for decompensated cirrhotic liver disease. Liver fibrosis can result from different underlying chronic liver disease, such as chronic viral infection, excessive alcohol consumption, fatty liver disease or autoimmune liver diseases. It is becoming increasingly recognised that as a result from different pathogenic mechanisms liver fibrosis must be considered as many different diseases for which individual treatment strategies need to be developed. Moreover, the pathogenic changes of both liver architecture and vascularisation in cirrhotic livers, as well as the lack of "true-to-life" in vitro models have impeded the development of an effective anti-fibrogenic drug. Thus, in order to identify an efficient anti-fibrogenic compound, novel in-vitro models mimicking the interplay between pro-fibrogenic cell populations, immune cells and, importantly, the extracellular matrix need to be developed.

Primary sclerosing cholangitis and the management of uncertainty and complexity

Primary sclerosing cholangitis (PSC) is a rare chronic autoimmune disease with no effective therapy and a large unmet need for new treatments. Patients require significant healthcare resources over their lifetime with high rates of hospital admission, malignancy, liver transplantation and death. As a rare disease, expertise in management can be limited to large referral liver transplant programmes, and even then there is frequently variation in practice. In this case-based review, we aim to discuss common clinical dilemmas encountered by clinicians managing patients with PSC and address related competencies in the 2010 Gastroenterology Curriculum.

Lactation-Based Maternal Educational Immunity Crosses MHC Class I Barriers and Can Impart Th1 Immunity to Th2-Biased Recipients

We have previously demonstrated lactational transfer of T cell-based immunity from dam to foster pup. In the short term, a significant part of transferred immunity is passive cellular immunity. However, as time progresses, this is replaced by what we have described as maternal educational immunity such that by young adulthood, all immune cells responding to a foster dam immunogen are the product of the foster pup's thymus. To reduce confounding factors, this original demonstration used congenic/syngeneic dam and foster pup pairs. In this study, we investigated lactational transfer of immunity to Mycobacterium tuberculosis in MHC class I-mismatched animals, as well as from Th1-biased dams to Th2-biased foster pups. Using immunized C57BL/6J dams, lactational transfer to nonimmunized BALB/cJ foster pups resulted in much greater immunity than direct immunization in 5-wk-old pups (ex vivo assay of pup splenocytes). At this age, 82% of immunogen-responding cells in the pup spleen were produced through maternal educational immunity. FVB/NJ nonimmunized foster recipients had a greater number of maternal cells in the spleen and thymus but a much larger percentage was Foxp3⁺, resulting in equivalent immunity to direct immunization. Depletion of maternal Foxp3⁺ cells from pup splenocytes illustrated a substantial role for lactationally transferred dam regulatory T cells in suppression of the ex vivo response in FVB/NJ, but not BALB/cJ, recipients. We conclude that lactational transfer of immunity can cross MHC class I barriers and that Th1 immunity can be imparted to Th2-biased offspring; in some instances, it can be greater than that achieved by direct immunization.