Hepatoprotective and anti-fibrotic functions of interleukin-22: therapeutic potential for the treatment of alcoholic liver disease

Exploring the double-edged role of cellular senescence in chronic liver disease for new treatment approaches

Cellular senescence is a fundamental yet complex defense mechanism that restricts excessive proliferation, maintains cellular homeostasis under various stress conditions-such as oncogenic activation and inflammation-and serves as a dynamic stress response program involved in development, aging, and immunity. Its reversibility depends on essential maintenance components. Cellular senescence is a "double-edged sword": on one hand, it limits the malignant proliferation of damaged cells, thereby preventing tumor development. However, by retaining secretory functions, senescent cells can also induce persistent changes in the microenvironment and disrupt homeostasis, leading to tissue inflammation, fibrosis, and carcinogenesis. Senescence plays a critical role in the pathogenesis of various chronic liver diseases, including chronic viral hepatitis, liver fibrosis, and hepatocellular carcinoma. It exerts a dual influence by facilitating immune evasion and inflammation in chronic viral hepatitis, modulating hepatic stellate cell activity in fibrosis, and reshaping the tumor microenvironment to accelerate hepatocarcinogenesis. This article reviews the characteristics of cellular senescence and its role in the pathogenesis of these chronic liver diseases while exploring potential treatment and prevention strategies. The aim is to provide a comprehensive reference for future clinical and research investigations into chronic liver disease.

Immunological mechanisms and emerging therapeutic targets in alcohol-associated liver disease

Alcohol-associated liver disease (ALD) is a major global health challenge, with inflammation playing a central role in its progression. As inflammation emerges as a critical therapeutic target, ongoing research aims to unravel its underlying mechanisms. This review explores the immunological pathways of ALD, highlighting the roles of immune cells and their inflammatory mediators in disease onset and progression. We also examine the complex interactions between inflammatory cells and non-parenchymal liver cells, as well as their crosstalk with extra-hepatic organs, including the gut, adipose tissue, and nervous system. Furthermore, we summarize current clinical research on anti-inflammatory therapies and discuss promising therapeutic targets. Given the heterogeneity of ALD-associated inflammation, we emphasize the need for precision medicine to optimize treatment strategies and improve patient outcomes.

Navigating the Paradox of IL-22: Friend or Foe in Hepatic Health?

Interleukin-22 (IL-22), a cytokine from the IL-10 family produced by T cells and innate lymphoid cells, plays a crucial role in immune responses and tissue regeneration. Its association with liver disease has garnered significant attention; however, its exact impact remains controversial. This review aims to enhance the current understanding of the dual role of IL-22 in liver disease by exploring its protective and pathogenic effects. First, we provide an overview of IL-22 biology, including its source, receptors, and signaling pathways. Subsequently, we offer a comprehensive overview of the dual function of IL-22 in non-neoplastic liver disease, emphasizing its antiapoptotic and regenerative properties. We also discuss the applicability of the conclusions drawn from studies on nonalcoholic fatty liver disease to metabolic dysfunction-associated steatotic liver disease. Furthermore, we elaborate on the intricate role of IL-22 in hepatocellular carcinoma, particularly its influence on the tumor microenvironment, proliferation, and immune evasion. In conclusion, IL-22 is paradoxical in liver disease, acting as a friend and foe. It is imperative to understand this paradox to develop targeted therapies that capitalize on the beneficial effects of IL-22 while mitigating its detrimental effects.

An Update on IL-22 Therapies in Alcohol-Associated Liver Disease and Beyond

Excessive alcohol consumption drives the development of alcohol-associated liver disease (ALD), including steatohepatitis, cirrhosis, and hepatocellular carcinoma, and its associated complications, such as hepatorenal syndrome. Hepatocyte death, inflammation, and impaired liver regeneration are key processes implicated in the pathogenesis and progression of ALD. Despite extensive research, therapeutic options for ALD remain limited. IL-22 has emerged as a promising therapeutic target because of its hepatoprotective properties mediated through the activation of the STAT3 signaling pathway. IL-22 enhances hepatocyte survival by mitigating apoptosis, oxidative stress, and inflammation while simultaneously promoting liver regeneration through the proliferation of hepatocytes and hepatic progenitor cells and the up-regulation of growth factors. Additionally, IL-22 exerts protective effects on epithelial cells in various organs affected by ALD and its associated complications. Studies from preclinical models and early-phase clinical trials of IL-22 agonists, such as F-652 and UTTR1147A, have shown favorable safety profiles, good tolerability, and encouraging efficacy in reducing liver injury and promoting regeneration. However, the heterogeneity and multifactorial nature of ALD present ongoing challenges. Further research is needed to optimize IL-22-based therapies and clarify their roles within a comprehensive approach to ALD management. This review summarizes the current understanding of IL-22 biology and its role in ALD pathophysiology and ALD-associated complications along with therapeutic application of IL-22, potential benefits, and limitations.

IL-22, a vital cytokine in autoimmune diseases

Interleukin-22 (IL-22) is a vital cytokine that is dysregulated in various autoimmune conditions including rheumatoid arthritis (RA), multiple sclerosis (MS), and Alzheimer's disease (AD). As the starting point for the activation of numerous signaling pathways, IL-22 plays an important role in the initiation and development of autoimmune diseases. Specifically, imbalances in IL-22 signaling can interfere with other signaling pathways, causing cross-regulation of target genes which ultimately leads to the development of immune disorders. This review delineates the various connections between the IL-22 signaling pathway and autoimmune disease, focusing on the latest understanding of the cellular sources of IL-22 and its effects on various cell types. We further explore progress with pharmacological interventions related to targeting IL-22, describing how such therapeutic strategies promise to usher in a new era in the treatment of autoimmune disease.

Elevated serum hepatic transaminases in apical periodontitis individuals

AIM

Apical periodontitis (AP) is the chronic inflammation of the periradicular tissues in response to root canal infection. Whilst AP has been linked with systemic inflammation and noncommunicable diseases, its potential association with nonalcoholic fatty liver disease (NAFLD) is unknown. We aimed to evaluate the serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels as surrogate markers of hepatic injury, and the systemic inflammatory burden in otherwise healthy individuals with and without AP diagnosis.

METHODOLOGY

Cross-sectional study. Individuals with AP (n = 30) and healthy controls (n = 29) were recruited. The number, mean diameter (mm) and periapical index of the apical lesions of endodontic origin (ALEO) were assessed. ALT and AST levels (pg/mL) were measured through enzyme-linked immunosorbent assays. The serum levels of TNF-α, IL-4, IL-9, IL-10, IL-17A and IL-22 were evaluated by Multiplex assay. Inferential analysis was performed using t-test or Mann-Whitney tests according to data distribution and linear regression models. Data were analysed with StataV16 (p < .05).

RESULTS

ALT and AST levels were significantly higher in individuals with AP compared to controls (p < .05). Serum inflammatory biomarkers showed no significant differences between the study groups. Bivariate and multivariate analyses confirmed that AP diagnosis was independently associated with ALT and AST elevations (p < .05). Additionally, the number of ALEO positively influenced AST levels (p = .002). IL-22 on the other hand, was associated with reduced ALT levels (p = .043).

CONCLUSION

AP is associated with higher serum hepatic transaminases ALT and AST, potentially contributing to NAFLD physiopathology in young adults.

Review of the potential value of serum interleukin levels as prognostic biomarkers of liver failure

Liver failure (LF) is prevalent in China and is characterized by complex pathogenesis, challenging clinical management, poor prognosis, and rising incidence and mortality rates. The immune status is an important factor affecting LF prognosis. Interleukins (Ils) are a type of cytokine that act and interact with multiple cells, including immune cells. These signaling molecules play important roles in intercellular information transmission, including the regulation of immune cells; mediation of the activation, proliferation, and differentiation of T and B cells; and orchestration of the inflammatory response. To date, many studies have explored the correlation between IL expression and liver disease prognosis, but few studies have evaluated Ils as the prognostic biomarkers of LF. This article reviews the potential use of Ils as the prognostic biomarkers of LF. Particularly, it evaluates the predictive values of IL-21, IL-22, and IL-31, the three often overlooked yet promising prognostic biomarkers, in predicting susceptibility to LF. Harnessing biomarkers for early prognostic insights can facilitate tailored treatment strategies and enhance patient survival. Thus, this article focuses on the identification of IL-21, IL-22, and IL-33 as biomarkers in preclinical and clinical studies on LF and reviews their role as biomarkers in the pathogenesis and diagnosis of LF.

Role of Neutrophils in the Development of Steatotic Liver Disease

This review explores the biological aspects of neutrophils, their contributions to the development of steatotic liver disease, and their potential as therapeutic targets for the disease. Although alcohol-associated and metabolic dysfunction-associated liver diseases originate from distinct etiological factors, the two diseases frequently share excessive lipid accumulation as a common contributor to their pathogenesis, thereby classifying them as types of steatotic liver disease. Dysregulated lipid deposition in the liver induces hepatic injury, triggering the activation of the innate immunity, partially through neutrophil recruitment. Traditionally recognized for their role in microbial clearance, neutrophils have recently garnered attention for their involvement in sterile inflammation, a pivotal component of steatotic liver disease pathogenesis. In conclusion, technological innovations, including single-cell RNA sequencing, have gradually disclosed the existence of various neutrophil subsets; however, how the distinct subsets of neutrophil population contribute differentially to the development of steatotic liver disease remains unclear.

Ovarian fibrosis: molecular mechanisms and potential therapeutic targets

Ovarian fibrosis, characterized by the excessive proliferation of ovarian fibroblasts and the accumulation of extracellular matrix (ECM), serves as one of the primary causes of ovarian dysfunction. Despite the critical role of ovarian fibrosis in maintaining the normal physiological function of the mammalian ovaries, research on this condition has been greatly underestimated, which leads to a lack of clinical treatment options for ovarian dysfunction caused by fibrosis. This review synthesizes recent research on the molecular mechanisms of ovarian fibrosis, encompassing TGF-β, extracellular matrix, inflammation, and other profibrotic factors contributing to abnormal ovarian fibrosis. Additionally, we summarize current treatment approaches for ovarian dysfunction targeting ovarian fibrosis, including antifibrotic drugs, stem cell transplantation, and exosomal therapies. The purpose of this review is to summarize the research progress on ovarian fibrosis and to propose potential therapeutic strategies targeting ovarian fibrosis for the treatment of ovarian dysfunction.

RAS-activated PI3K/AKT signaling sustains cellular senescence via P53/P21 axis in experimental models of psoriasis

BACKGROUND

Psoriasis is a chronic immune-mediated skin disease in which upper epidermal keratinocytes exhibit a senescent-like phenotype. In psoriatic skin, a variety of inflammatory cytokines can activate intracellular pathways including phosphatidylinositol 3-kinase (PI3K)/AKT signaling and RAS effectors. AKT and RAS participate to cellular senescence, but currently their role in senescence responses occurring in psoriasis have not yet been investigated.

OBJECTIVE

The role of AKT molecular axis and RAS activation was evaluated in the context of cellular senescence in psoriasis disease.

METHODS

RAS/AKT involvement in senescence was analyzed in psoriatic keratinocytes cultures subjected to multiple passages to promote senescence in vitro, as well as in skin lesions of patients affected by psoriasis. The impact of pharmacological inhibition of PI3K/AKT pathway on senescence and inflammation responses was tested in senescent psoriatic keratinocytes and in a psoriasiform dermatitis murine model induced by RAS overexpression in the upper epidermis of mice.

RESULTS

We found AKT hyperactivation associated to the upregulation of senescence markers, in senescent psoriatic keratinocyte cultures, as well as in skin lesions of psoriatic patients. AKT-induced senescence was sustained by constitutive RAS activation, and down-stream responses were mediated by P53/P21 axis. PI3K/AKT inhibition contrasted senescence processes induced by cytokines in psoriatic keratinocytes. Additionally, RAS-induced psoriasis-like dermatitis in mice was accompanied by AKT upregulation, increase of senescence marker expression and by skin inflammation. In this model, both senescence and inflammation were significantly reduced by selective AKT inhibition.

CONCLUSION

Therefore, targeting RAS-AKT pathway could be a promising novel strategy to counteract multiple psoriasis symptoms.

Inflammation and Neurodegeneration in Glaucoma: Isolated Eye Disease or a Part of a Systemic Disorder? - Serum Proteomic Analysis

Introduction

Glaucoma is the most common optic neuropathy and the leading cause of irreversible blindness worldwide, which affects 3.54% of the population aged 40-80 years. Despite numerous published studies, some aspects of glaucoma pathogenesis, serum biomarkers, and their potential link with other diseases remain unclear. Recent articles have proposed that autoimmune, oxidative stress and inflammation may be involved in the pathogenesis of glaucoma.

Methods

We investigated the serum expression of 92 inflammatory and neurotrophic factors in glaucoma patients. The study group consisted of 26 glaucoma patients and 192 healthy subjects based on digital fundography.

Results

Patients with glaucoma had significantly lower serum expression of IL-2Rβ, TWEAK, CX3CL1, CD6, CD5, LAP TGF-beta1, LIF-R, TRAIL, NT-3, and CCL23 and significantly higher expression of IL-22Rα1.

Conclusion

Our results indicate that patients with glaucoma tend to have lower levels of neuroprotective proteins and higher levels of neuroinflammatory proteins, similar to those observed in psychiatric, neurodegenerative and autoimmune diseases, indicating a potential link between these conditions and glaucoma pathogenesis.

Cellular Senescence in Liver Cancer: How Dying Cells Become "Zombie" Enemies

Liver cancer represents the fourth leading cause of cancer-associated death worldwide. The heterogeneity of its tumor microenvironment (TME) is a major contributing factor of metastasis, relapse, and drug resistance. Regrettably, late diagnosis makes most liver cancer patients ineligible for surgery, and the frequent failure of non-surgical therapeutic options orientates clinical research to the investigation of new drugs. In this context, cellular senescence has been recently shown to play a pivotal role in the progression of chronic inflammatory liver diseases, ultimately leading to cancer. Moreover, the stem-like state triggered by senescence has been associated with the emergence of drug-resistant, aggressive tumor clones. In recent years, an increasing number of studies have emerged to investigate senescence-associated hepatocarcinogenesis and its derived therapies, leading to promising results. In this review, we intend to provide an overview of the recent evidence that unveils the role of cellular senescence in the most frequent forms of primary and metastatic liver cancer, focusing on the involvement of this mechanism in therapy resistance.

The Origin and Fate of Liver Myofibroblasts

Liver fibrosis of different etiologies is a serious health problem worldwide. There is no effective therapy available for liver fibrosis except the removal of the underlying cause of injury or liver transplantation. Development of liver fibrosis is caused by fibrogenic myofibroblasts that are not present in the normal liver, but rather activate from liver resident mesenchymal cells in response to chronic toxic or cholestatic injury. Many studies indicate that liver fibrosis is reversible when the causative agent is removed. Regression of liver fibrosis is associated with the disappearance of activated myofibroblasts and resorption of the fibrous scar. In this review, we discuss the results of genetic tracing and cell fate mapping of hepatic stellate cells and portal fibroblasts, their specific characteristics, and potential phenotypes. We summarize research progress in the understanding of the molecular mechanisms underlying the development and reversibility of liver fibrosis, including activation, apoptosis, and inactivation of myofibroblasts.

Cellular senescence in liver diseases: From mechanisms to therapies

Cellular senescence is an irreversible state of cell cycle arrest, characterized by a gradual decline in cell proliferation, differentiation, and biological functions. Cellular senescence is double-edged for that it can provoke organ repair and regeneration in physiological conditions but contribute to organ and tissue dysfunction and prime multiple chronic diseases in pathological conditions. The liver has a strong regenerative capacity, where cellular senescence and regeneration are closely involved. Herein, this review firstly introduces the morphological manifestations of senescent cells, the major regulators (p53, p21, and p16), and the core pathophysiologic mechanisms underlying senescence process, and then specifically generalizes the role and interventions of cellular senescence in multiple liver diseases, including alcoholic liver disease, nonalcoholic fatty liver disease, liver fibrosis, and hepatocellular carcinoma. In conclusion, this review focuses on interpreting the importance of cellular senescence in liver diseases and summarizes potential senescence-related regulatory targets, aiming to provide new insights for further researches on cellular senescence regulation and therapeutic developments for liver diseases.

Emerging Pharmacotherapies in Alcohol-Associated Hepatitis

The incidence of alcoholic-associated hepatitis (AH) is increasing. The treatment options for severe AH (sAH) are scarce and limited to corticosteroid therapy which showed limited mortality benefit in short-term use only. Therefore, there is a dire need for developing safe and effective therapies for patients with sAH and to improve their high mortality rates.This review article focuses on the current novel therapeutics targeting various mechanisms in the pathogenesis of alcohol-related hepatitis. Anti-inflammatory agents such as IL-1 inhibitor, Pan-caspase inhibitor, Apoptosis signal-regulating kinase-1, and CCL2 inhibitors are under investigation. Other group of agents include gut-liver axis modulators, hepatic regeneration, antioxidants, and Epigenic modulators. We describe the ongoing clinical trials of some of the new agents for alcohol-related hepatitis.

CONCLUSION

A combination of therapies was investigated, possibly providing a synergistic effect of drugs with different mechanisms. Multiple clinical trials of novel therapies in AH remain ongoing. Their result could potentially make a difference in the clinical course of the disease. DUR-928 and granulocyte colony-stimulating factor had promising results and further trials are ongoing to evaluate their efficacy in the large patient sample.

Therapeutic targets in alcohol-associated liver disease: progress and challenges

Alcohol-associated liver disease (ALD) is a complex disease with rapidly increasing prevalence. Although there are promising therapeutic targets on the horizon, none of the newer targets is currently close to an Food and Drug Administration approval. Strategies are needed to overcome challenges in study designs and conducting clinical trials and provide impetus to the field of drug development in the landscape of ALD and alcoholic hepatitis. Management of ALD is complex and should include therapies to achieve and maintain alcohol abstinence, preferably delivered by a multidisciplinary team. Although associated with clear mortality benefit in select patients, the use of early liver transplantation still requires refinement to create uniformity in selection protocols across transplant centers. There is also a need for reliable noninvasive biomarkers for prognostication. Last but not the least, strategies are urgently needed to implement integrated multidisciplinary care models for treating the dual pathology of alcohol use disorder and of liver disease for improving the long-term outcomes of patients with ALD.

Cellular Senescence in Hepatocellular Carcinoma: The Passenger or the Driver?

With the high morbidity and mortality, hepatocellular carcinoma (HCC) represents a major yet growing burden for our global community. The relapse-prone nature and drug resistance of HCC are regarded as the consequence of varying intracellular processes and extracellular interplay, which actively participate in tumor microenvironment remodeling. Amongst them, cellular senescence is regarded as a fail-safe program, leading to double-sword effects of both cell growth inhibition and tissue repair promotion. Particularly, cellular senescence serves a pivotal role in the progression of chronic inflammatory liver diseases, ultimately leading to carcinogenesis. Given the current challenges in improving the clinical management and outcome of HCC, senescence may exert striking potential in affecting anti-cancer strategies. In recent years, an increasing number of studies have emerged to investigate senescence-associated hepatocarcinogenesis and its derived therapies. In this review, we intend to provide an up-to-date understanding of liver cell senescence and its impacts on treatment modalities of HCC.

Metabolic Injury of Hepatocytes Promotes Progression of NAFLD and AALD

Nonalcoholic liver disease is a component of metabolic syndrome associated with obesity, insulin resistance, and hyperlipidemia. Excessive alcohol consumption may accelerate the progression of steatosis, steatohepatitis, and fibrosis. While simple steatosis is considered a benign condition, nonalcoholic steatohepatitis with inflammation and fibrosis may progress to cirrhosis, liver failure, and hepatocellular cancer. Studies in rodent experimental models and primary cell cultures have demonstrated several common cellular and molecular mechanisms in the pathogenesis and regression of liver fibrosis. Chronic injury and death of hepatocytes cause the recruitment of myeloid cells, secretion of inflammatory and fibrogenic cytokines, and activation of myofibroblasts, resulting in liver fibrosis. In this review, we discuss the role of metabolically injured hepatocytes in the pathogenesis of nonalcoholic steatohepatitis and alcohol-associated liver disease. Specifically, the role of chemokine production and de novo lipogenesis in the development of steatotic hepatocytes and the pathways of steatosis regulation are discussed.

Human Umbilical Cord Blood Mononuclear Cells Ameliorate CCl4-Induced Acute Liver Injury in Mice via Inhibiting Inflammatory Responses and Upregulating Peripheral Interleukin-22

Background: Human umbilical cord blood mononuclear cells (hUCBMNCs) show therapeutic effects on many inflammatory diseases. The deterioration of acute liver injury is attributed to excessive inflammatory responses triggered by damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs). Whether hUCBMNCs treatment is a promising strategy for acute liver injury/failure needs to be investigated.

Methods: Liver injury mice induced by PAMPs, DAMPs, or DAMPs plus PAMPs were developed. DAMPs included CCl4 (carbon tetrachloride), APAP (acetaminophen), and ConA (Concanavalin A). PAMPs included Klebsiella pneumoniae (K.P.) and Salmonella typhimurium (S. Typhimurium). DAMP plus PAMP-induced liver injury was developed by sequential CCl4 and K.P. administration. hUCBMNCs were injected intravenously.

Results: hUCBMNCs significantly prolonged mice survival time in DAMP plus PAMP-induced liver failure but had no benefit in bacteria-infected mice. hUCBMNCs significantly alleviated hepatic necrosis post CCl4/ConA insult. In CCl4-induced acute liver injury, peripheral levels of interleukin (IL)-22 were upregulated and liver regeneration was enhanced after treating with hUCBMNCs at 48h. The levels of p62 and LC3B-II, autophagy markers, were also upregulated in the hUCBMNC-treated group.

Conclusion: hUCBMNCs as a kind of cell therapeutic strategy could attenuate acute liver injury in mice, which is executed by enhancing autophagy and regeneration in the liver via inhibiting inflammatory responses and upregulating peripheral IL-22.

Emerging Evidence of Noncoding RNAs in Bleb Scarring after Glaucoma Filtration Surgery

PURPOSE

To conduct a narrative review of research articles on the potential anti- and pro-fibrotic mechanisms of noncoding RNAs following glaucoma filtration surgery.

METHODS

Keyword searches of PubMed, and Medline databases were conducted for articles discussing post-glaucoma filtration surgeries and noncoding RNA. Additional manual searches of reference lists of primary articles were performed.

RESULTS

Fifteen primary research articles were identified. Four of the included papers used microarrays and qRT-PCR to identify up- or down-regulated microRNA (miRNA, miR) profiles and direct further study, with the remainder focusing on miRNAs or long noncoding RNAs (lncRNAs) based on previous work in other organs or disease processes. The results of the reviewed papers identified miR-26a, -29b, -139, -155, and -200a as having anti-fibrotic effects. In contrast, miRs-200b and -216b may play pro-fibrotic roles in filtration surgery fibrosis. lncRNAs including H19, NR003923, and 00028 have demonstrated pro-fibrotic effects.

CONCLUSIONS

Noncoding RNAs including miRNAs and lncRNAs are emerging and promising therapeutic targets in the prevention of post-glaucoma filtration surgery fibrosis.

Crosstalk between Oxidative Stress and Inflammatory Liver Injury in the Pathogenesis of Alcoholic Liver Disease

Alcoholic liver disease (ALD) is characterized by the injury, inflammation, and scarring in the liver owing to excessive alcohol consumption. Currently, ALD is a leading cause for liver transplantation. Therefore, extensive studies (in vitro, in experimental ALD models and in humans) are needed to elucidate pathological features and pathogenic mechanisms underlying ALD. Notably, oxidative changes in the liver have been recognized as a signature trait of ALD. Progression of ALD is linked to the generation of highly reactive free radicals by reactions involving ethanol and its metabolites. Furthermore, hepatic oxidative stress promotes tissue injury and, in turn, stimulates inflammatory responses in the liver, forming a pathological loop that promotes the progression of ALD. Accordingly, accumulating further knowledge on the relationship between oxidative stress and inflammation may help establish a viable therapeutic approach for treating ALD.

Therapeutic potential of targeting regulatory mechanisms of hepatic stellate cell activation in liver fibrosis

Hepatic fibrosis is a manifestation of different etiologies of liver disease with the involvement of multiple mediators in complex network interactions. Activated hepatic stellate cells (aHSCs) are the central driver of hepatic fibrosis, given their potential to induce connective tissue formation and extracellular matrix (ECM) protein accumulation. Therefore, identifying the cellular and molecular pathways involved in the activation of HSCs is crucial in gaining mechanistic and therapeutic perspectives to more effectively target the disease. In addition to a comprehensive summary of our current understanding of the role of HSCs in liver fibrosis, we also discuss here the proposed therapeutic strategies based on targeting HSCs.

Emerging Therapies for Alcoholic Hepatitis

The incidence of alcoholic hepatitis is increasing while the mortality rate remains high. The single current available therapy for severe alcoholic hepatitis is administration of corticosteroids for patients with severe alcoholic hepatitis, which has demonstrated limited benefits, providing a short-term mortality benefit with a marginal response rate. There is a need for developing safe and effective therapies. This article reviews novel therapies targeting various mechanisms in the pathogenesis of alcoholic hepatitis, such as the gut-liver axis, inflammatory cascade, oxidative stress, and hepatic regeneration. Current ongoing clinical trials for alcoholic hepatitis also are described.

The good and the bad about separation anxiety: roles of IL-22 and IL-22BP in liver pathologies

The human liver fulfills several vital tasks daily and possesses an impressive ability to self-regenerate. However, the capacity of this self-healing process can be exhausted by a variety of different liver diseases, such as alcoholic liver damage, viral hepatitis, or hepatocellular carcinoma. Over time, all these diseases generally lead to progressive liver failure that can become fatal if left untreated. Thus, a great effort has been directed towards the development of innovative therapies. The most recently discovered therapies often involve modifying the patient's immune system to enhance a beneficial immune response. Current data suggest that, among others, the cytokine IL-22 might be a promising therapeutical candidate. IL-22 and its endogenous antagonist, IL-22BP, have been under thorough scientific investigation for nearly 20 years. While IL-22 is mainly produced by TH22 cells, ILC3s, NKT cells, or γδ T cells, sources of IL-22BP include dendritic cells, eosinophils, and CD4+ cells. In many settings, IL-22 was shown to promote regenerative potential and, thus, could protect tissues from pathogens and damage. However, the effects of IL-22 during carcinogenesis are more ambiguous and depend on the tumor entity and microenvironment. In line with its capabilities of neutralizing IL-22 in vivo, IL-22BP possesses often, but not always, an inverse expression pattern compared to its ligand. In this comprehensive review, we will summarize past and current findings regarding the roles of IL-22 and IL-22BP in liver diseases with a particular focus on the leading causes of advanced liver failure, namely, liver infections, liver damage, and liver malignancies.

Indole-3-Carboxaldehyde Restores Gut Mucosal Integrity and Protects from Liver Fibrosis in Murine Sclerosing Cholangitis

Primary sclerosing cholangitis (PSC) is a long-term liver disease characterized by a progressive course of cholestasis with liver inflammation and fibrosis. Intestinal barrier dysfunction has been implicated in the pathogenesis of PSC. According to the "leaky gut" hypothesis, gut inflammation alters the permeability of the intestinal mucosa, with the translocation of gut-derived products that enter the enterohepatic circulation and cause hepatic inflammation. Thus, the administration of molecules that preserve epithelial barrier integrity would represent a promising therapeutic strategy. Indole-3-carboxaldehyde (3-IAld) is a microbial-derived product working at the interface between the host and the microbiota and is able to promote mucosal immune homeostasis in a variety of preclinical settings. Herein, by resorting to a murine model of PSC, we found that 3-IAld formulated for localized delivery in the gut alleviates hepatic inflammation and fibrosis by modulating the intestinal microbiota and activating the aryl hydrocarbon receptor-IL-22 axis to restore mucosal integrity. This study points to the therapeutic potential of 3-IAld in liver pathology.

Nonalcoholic Steatohepatitis and HCC in a Hyperphagic Mouse Accelerated by Western Diet

BACKGROUND & AIMS

How benign liver steatosis progresses to nonalcoholic steatohepatitis (NASH), fibrosis, and hepatocellular carcinoma (HCC) remains elusive. NASH progression entails diverse pathogenic mechanisms and relies on complex cross-talk between multiple tissues such as the gut, adipose tissues, liver, and the brain. Using a hyperphagic mouse fed with a Western diet (WD), we aimed to elucidate the cross-talk and kinetics of hepatic and extrahepatic alterations during NASH-HCC progression, as well as regression.

METHODS

Hyperphagic mice lacking a functional Alms1 gene (Foz/Foz) and wild-type littermates were fed WD or standard chow for 12 weeks for NASH/fibrosis and for 24 weeks for HCC development. NASH regression was modeled by switching back to normal chow after NASH development.

RESULTS

Foz+WD mice were steatotic within 1 to 2 weeks, developed NASH by 4 weeks, and grade 3 fibrosis by 12 weeks, accompanied by chronic kidney injury. Foz+WD mice that continued on WD progressed to cirrhosis and HCC within 24 weeks and had reduced survival as a result of cardiac dysfunction. However, NASH mice that were switched to normal chow showed NASH regression, improved survival, and did not develop HCC. Transcriptomic and histologic analyses of Foz/Foz NASH liver showed strong concordance with human NASH. NASH was preceded by an early disruption of gut barrier, microbial dysbiosis, lipopolysaccharide leakage, and intestinal inflammation. This led to acute-phase liver inflammation in Foz+WD mice, characterized by neutrophil infiltration and increased levels of several chemokines/cytokines. The liver cytokine/chemokine profile evolved as NASH progressed, with subsequent predominance by monocyte recruitment.

CONCLUSIONS

The Foz+WD model closely mimics the pathobiology and gene signature of human NASH with fibrosis and subsequent HCC. Foz+WD mice provide a robust and relevant preclinical model of NASH, NASH-associated HCC, chronic kidney injury, and heart failure.

Alcoholic and Non-Alcoholic Liver Diseases: Promising Molecular Drug Targets and their Clinical Development

Alcoholic and non-alcoholic fatty liver diseases have become a serious concern worldwide. Both these liver diseases have an identical pathology, starting from simple steatosis to cirrhosis and, ultimately to hepatocellular carcinoma. Treatment options for alcoholic liver disease (ALD) are still the same as they were 50 years ago which include corticosteroids, pentoxifylline, antioxidants, nutritional support and abstinence; and for non-alcoholic fatty liver disease (NAFLD), weight loss, insulin sensitizers, lipid-lowering agents and anti-oxidants are the only treatment options. Despite broad research in understanding the disease pathophysiology, limited treatments are available for clinical use. Some therapeutic strategies based on targeting a specific molecule have been developed to lessen the consequences of disease and are under clinical investigation. Therefore, focus on multiple molecular targets will help develop an efficient therapeutic strategy. This review comprises a brief overview of the pathogenesis of ALD and NAFLD; recent molecular drug targets explored for ALD and NAFLD that may prove to be effective for multiple therapeutic regimens and also the clinical status of these promising drug targets for liver diseases.

Synergistic effect of the TLR5 agonist CBLB502 and its downstream effector IL-22 against liver injury

The toll-like receptor 5 (TLR5) agonist, CBLB502/Entolimod, is a peptide derived from bacterial flagellin and has been shown to protect against radiation-induced tissue damage in animal models. Here we investigated the protective mechanism of CBLB502 in the liver using models of ischemia-reperfusion injury and concanavalin A (ConA) induced immuno-hepatitis. We report that pretreatment of mice with CBLB502 provoked a concomitant activation of NF-κB and STAT3 signaling in the liver and reduced hepatic damage in both models. To understand the underlying mechanism, we screened for cytokines in the serum of CBLB502 treated animals and detected high levels of IL-22. There was no transcriptional upregulation of IL-22 in the liver, rather it was found in extrahepatic tissues, mainly the colon, mesenteric lymph nodes (MLN), and spleen. RNA-seq analysis on isolated hepatocytes demonstrated that the concomitant activation of NF-κB signaling by CBLB502 and STAT3 signaling by IL-22 produced a synergistic cytoprotective transcriptional signature. In IL-22 knockout mice, the loss of IL-22 resulted in a decrease of hepatic STAT3 activation, a reduction in the cytoprotective signature, and a loss of hepatoprotection following ischemia-reperfusion-induced liver injury. Taken together, these findings suggest that CBLB502 protects the liver by increasing hepatocyte resistance to acute liver injury through the cooperation of TLR5-NF-κB and IL-22-STAT3 signaling pathways.

Hydrogen-rich water protects against liver injury in nonalcoholic steatohepatitis through HO-1 enhancement via IL-10 and Sirt 1 signaling

Nonalcoholic steatohepatitis (NASH) could progress to hepatic fibrosis in the absence of effective control. The purpose of our experiment was to investigate the protective effect of drinking water with a high concentration of hydrogen, namely, hydrogen-rich water (HRW), on mice with nonalcoholic fatty liver disease to elucidate the mechanism underlying the therapeutic action of molecular hydrogen. The choline-supplemented, l-amino acid-defined (CSAA) or the choline-deficient, l-amino acid-defined (CDAA) diet for 20 wk was used to induce NASH and fibrosis in the mice model and simultaneously treated with the high-concentration 7-ppm HRW for different periods (4 wk, 8  wk, and 20 wk). Primary hepatocytes were stimulated by palmitate to mimic liver lipid metabolism during fatty liver formation. Primary hepatocytes were cultured in a closed vessel filled with 21% O₂ + 5% CO₂ + 3.8% H₂ and N₂ as the base gas to verify the response of primary hepatocytes in a high concentration of hydrogen gas in vitro. Mice in the CSAA + HRW group had lower serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and milder histological damage. The inflammatory cytokines were expressed at lower levels in the HRW group than in the CSAA group. Importantly, HRW reversed hepatocyte fatty acid oxidation and lipogenesis as well as hepatic inflammation and fibrosis in preexisting hepatic fibrosis specimens. Molecular hydrogen inhibits the lipopolysaccharide-induced production of inflammation cytokines through increasing heme oxygenase-1 (HO-1) expression. Furthermore, HRW improved hepatic steatosis in the CSAA + HRW group. Sirtuin 1 (Sirt1) induction by molecular hydrogen via the HO-1/adenosine monophosphate activated protein kinase (AMPK)/peroxisome proliferator-activated receptor α (PPARα)/peroxisome proliferator-activated receptor γ (PPAR-γ) pathway suppresses palmitate-mediated abnormal fat metabolism. Orally administered HRW suppressed steatosis induced by CSAA and attenuated fibrosis induced by CDAA, possibly by reducing oxidative stress and the inflammation response.NEW & NOTEWORTHY The mRNA expression of inflammatory cytokines in the HRW group was lower than in the CSAA group. HRW reversed hepatocyte apoptosis as well as hepatic inflammation and fibrosis in NASH specimens. Molecular hydrogen inhibits LPS-induced inflammation via an HO-1/interleukin 10 (IL-10)-independent pathway. HRW improved hepatic steatosis in the CSAA + HRW group. Sirt1 induction by molecular hydrogen via the HO-1/AMPK/PPARα/PPARγ pathway suppresses palmitate-mediated abnormal fat metabolism.

Molecular and cellular mechanisms of liver fibrosis and its regression

Chronic liver injury leads to liver inflammation and fibrosis, through which activated myofibroblasts in the liver secrete extracellular matrix proteins that generate the fibrous scar. The primary source of these myofibroblasts are the resident hepatic stellate cells. Clinical and experimental liver fibrosis regresses when the causative agent is removed, which is associated with the elimination of these activated myofibroblasts and resorption of the fibrous scar. Understanding the mechanisms of liver fibrosis regression could identify new therapeutic targets to treat liver fibrosis. This Review summarizes studies of the molecular mechanisms underlying the reversibility of liver fibrosis, including apoptosis and the inactivation of hepatic stellate cells, the crosstalk between the liver and the systems that orchestrate the recruitment of bone marrow-derived macrophages (and other inflammatory cells) driving fibrosis resolution, and the interactions between various cell types that lead to the intracellular signalling that induces fibrosis or its regression. We also discuss strategies to target hepatic myofibroblasts (for example, via apoptosis or inactivation) and the myeloid cells that degrade the matrix (for example, via their recruitment to fibrotic liver) to facilitate fibrosis resolution and liver regeneration.

Interleukin-24 protects against liver injury in mouse models

Background

Interleukin-24 (IL-24) binds to two kinds of receptor complexes, namely IL-20R1/IL-20R2 and IL-20R2/IL-22R1, which are also bound by IL-20. IL-20 plays a detrimental role in liver fibrosis. Due to the sharing of receptor complexes, we aimed to determine whether IL-24 also participates in liver fibrosis.

Methods

Clinical biopsy specimens from various stages of liver fibrosis were used to analyze IL-24 expression. IL-24 protein was administered to mice with thioacetamide (TAA)-induced liver injury. The direct effects of IL-24 on mouse primary hepatocytes or hepatic stellate cells (HSCs) were analyzed. Wild-type, IL-20R1-, and IL20R2-deficient mice were used to establish a model of acute TAA-induced liver injury.

Findings

Among patients with more severe liver fibrosis, there was a reduced IL-24/IL-20 ratio. Administration of IL-24 protein protected mice from TAA-induced liver injury and reduction of liver inflammation by antioxidant effects. IL-24 protected hepatocytes from TAA-induced apoptosis and prevented liver fibrosis through the inhibition of the HSCs activation. The protective role of IL-24 acted on liver cells were mainly IL-20R1-independent. IL-20R2-deficient mice exhibited more severe liver injury upon TAA treatment, thus confirming the protective role of IL-24.

Interpretation

IL-24 plays a key protective role in the progression of liver injury and has therapeutic potential for treating liver injuries.

Funding

This work was supported by the Ministry of Science and Technology of Taiwan (MOST 106–2320-B-006–024) and Taiwan Liver Disease Prevention & Treatment Research Foundation.

Role of Neutrophils in the Pathogenesis of Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) includes a spectrum of liver disorders, from fatty liver to nonalcoholic steatohepatitis (NASH), cirrhosis, and hepatocellular carcinoma. Compared with fatty liver, NASH is characterized by increased liver injury and inflammation, in which liver-infiltrating immune cells, with neutrophil infiltration as a hallmark of NASH, play a critical role in promoting the progression of fatty liver to NASH. Neutrophils are the first responders to injury and infection in various tissues, establishing the first line of defense through multiple mechanisms such as phagocytosis, cytokine secretion, reactive oxygen species production, and neutrophil extracellular trap formation; however, their roles in the pathogenesis of NASH remain obscure. The current review summarizes the roles of neutrophils that facilitate the progression of fatty liver to NASH and their involvement in inflammation resolution during NASH pathogenesis. The notion that neutrophils are potential therapeutic targets for the treatment of NASH is also discussed.

Role of N-acetyl Cysteine in Post-transarterial Chemoembolization Transaminitis in Hepatocellular Carcinoma: A Single-center Experience

BACKGROUND

Transarterial chemoembolization (TACE) is the most common locoregional therapy for hepatocellular carcinoma (HCC). Postembolization syndrome is not an uncommon complication. At present, there is no specific treatment for management of this complication. We aimed to study the role of N-acetyl cysteine (NAC), an antioxidant, in management of this complication.

METHODS

In a prospective observational study, consecutive patients with HCC undergoing TACE from January 2016 to January 2017 were included. Patients with postembolization syndrome, defined as an elevation of transaminase levels more than 3-4 times the upper limit of normal, were administered intravenous NAC for 72 h (150 mg/kg for 1 h, then 12.5 mg/kg/h for 4 h, and continuous infusion 6.25 mg/h for the remaining 67 h). The other group received only supportive standard of care. The primary end point was reduction in post-TACE transaminitis.

RESULTS

Of 112 patients with HCC, 53 (47.3%) received NAC. The majority were cirrhotics in both the groups. Both groups were well matched in demographic, laboratory, and tumor characteristics. In the NAC group, there was significant reduction in Aspartate transaminase (AST) and Alanine transaminase (ALT) levels from day 1 to day 3 (p = 0.000) compared with the non-NAC group, with no significant change in bilirubin or international normalized ratio levels. The duration of hospital stay was similar in both the groups. None had any major adverse events to NAC.

CONCLUSION

This is a prospective, single-center experience, showing that early initiation of N-acetyl cysteine in those with post-TACE embolization syndrome reduces the transaminase level significantly.

Abnormal Innate Immunity in Acute-on-Chronic Liver Failure: Immunotargets for Therapeutics

Acute-on-chronic liver failure (ACLF) is a severe life-threatening condition with high risk of multiorgan failure, sepsis, and mortality. ACLF activates a multifaceted interplay of both innate and adaptive immune response in the host which governs the overall outcome. Innate immune cells recognize the conserved elements of microbial and viral origin, both to extort instant defense by transforming into diverse modules of effector responses and to generate long-lasting immunity but can also trigger a massive intrahepatic immune inflammatory response. Acute insult results in the activation of innate immune cells which provokes cytokine and chemokine cascade and subsequently initiates aggressive systemic inflammatory response syndrome, hepatic damage, and high mortality in ACLF. Dysregulated innate immune response not only plays a critical role in disease progression but also potentially correlates with clinical disease severity indices including Child-Turcotte-Pugh, a model for end-stage liver disease, and sequential organ failure assessment score. A better understanding of the pathophysiological basis of the disease and precise immune mechanisms associated with liver injury offers a novel approach for the development of new and efficient therapies to treat this severely ill entity. Immunotherapies could be helpful in targeting immune-mediated organ damage which may constrain progression toward liver failure and eventually reduce the requirement for liver transplantation. Here, in this review we discuss the defects of different innate immune cells in ACLF which updates the current knowledge of innate immune response and provide potential targets for new therapeutic interventions.

A Double Edged Sword Role of Interleukin-22 in Wound Healing and Tissue Regeneration

Wound healing and tissue regeneration is an intricate biological process that involves repair of cellular damage and maintenance of tissue integrity. Cascades involved in wound healing and tissue regeneration highly overlap with cancer causing pathways. Usually, subsequent tissue damage events include release of a number of cytokines to accomplish post-trauma restoration. IL-22 is one of the cytokines that are immediately produced to initiate immune response against several tissue impairments. IL-22 is a fundamental mediator in inflammation, mucous production, protective role against pathogens, wound healing, and tissue regeneration. However, accumulating evidence suggests pivotal role of IL-22 in instigation of various cancers due to its pro-inflammatory and tissue repairing activity. In this review, we summarize how healing effects of IL-22, when executed in an uncontrollable fashion can lead to carcinogenesis.

An Open-Label, Dose-Escalation Study to Assess the Safety and Efficacy of IL-22 Agonist F-652 in Patients With Alcohol-associated Hepatitis

BACKGROUND AND AIMS

Interleukin-22 has beneficial effects on inflammation and impaired hepatic regeneration that characterize alcohol-associated hepatitis (AH). F-652 is a recombinant fusion protein of human interleukin-22 and immunoglobulin G2 fragment crystallizable. This study aims to assess the safety and efficacy signals of F-652 in patients with moderate and severe AH.

APPROACH AND RESULTS

A phase-2 dose-escalating study was carried out. F-652 (10 μg/kg, 30 μg/kg, or 45 μg/kg) administered on days 1 and 7 was tested in 3 patients each with moderate (Model for End-Stage Liver Disease [MELD] scores: 11-20) and severe AH (MELD scores: 21-28). Safety was defined by absence of serious adverse events and efficacy was assessed by Lille score, changes in MELD score, and serum bilirubin and aminotransferases at days 28 and 42. Three independent propensity-matched comparator patient cohorts were used. Plasma extracellular vesicles and multiplex serum cytokines were measured to assess inflammation and hepatic regeneration. Eighteen patients (9 moderate and 9 severe AH) were enrolled, 66% were male, and the mean age was 48 years. The half-life of F-652 following the first dose was 61-85 hours. There were no serious adverse events leading to discontinuation. The MELD score and serum aminotransferases decreased significantly at days 28 and 42 from baseline (P < 0.05). Day-7 Lille score was 0.45 or less in 83% patients as compared with 6%, 12%, and 56% among the comparator cohorts. Extracellular vesicle counts decreased significantly at day 28 (P < 0.013). Cytokine inflammatory markers were down-regulated, and regeneration markers were up-regulated at days 28 and 42.

CONCLUSIONS

F-652 is safe in doses up to 45 μg/kg and associated with a high rate of improvement as determined by Lille and MELD scores, reductions in markers of inflammation and increases in markers of hepatic regeneration. This study supports the need for randomized placebo-controlled trials to test the efficacy of F-652 in AH.

Low Interleukin-22 Binding Protein Is Associated With High Mortality in Alcoholic Hepatitis and Modulates Interleukin-22 Receptor Expression

INTRODUCTION

In alcoholic hepatitis (AH), high interleukin (IL)-22 production is associated with disease improvement, purportedly through enhanced infection resistance and liver regeneration. IL-22 binding protein (BP) binds and antagonizes IL-22 bioactivity, but data on IL-22BP in liver disease suggest a complex interplay. Despite the scarcity of human data, IL-22 is in clinical trial as treatment of AH. We, therefore, in patients with AH, described the IL-22 system focusing on IL-22BP and associations with disease course, and mechanistically pursued the human associations in vitro.

METHODS

We prospectively studied 41 consecutive patients with AH at diagnosis, days 7 and 90, and followed them for up to 1 year. We measured IL-22 pathway proteins in liver biopsies and blood and investigated IL-22BP effects on IL-22 in hepatocyte cultures.

RESULTS

IL-22BP was produced in the gut and was identifiable in the patients with AH' livers. Plasma IL-22BP was only 50% of controls and the IL-22/IL-22BP ratio thus elevated. Consistently, IL-22-inducible genes were upregulated in AH livers at diagnosis. Low plasma IL-22BP was closely associated with high 1-year mortality. In vitro, IL-22 stimulation reduced IL-22 receptor (R) expression, but coincubation with IL-22BP sustained IL-22R expression. In the AH livers, IL-22R mRNA expression was similar to healthy livers, although IL-22R liver protein was higher at diagnosis.

DISCUSSION

Plasma IL-22BP was associated with an adverse disease course, possibly because its low level reduces IL-22R expression so that IL-22 bioactivity was reduced. This suggests the IL-BP interplay to be central in AH pathogenesis, and in future treatment trials (see Visual abstract, Supplementary Digital Content 5, http://links.lww.com/CTG/A338).

Interleukin 22 in Liver Injury, Inflammation and Cancer

Interleukin 22(IL-22), a member of the IL-10 cytokine family and is an emerging CD4+Th cytokine that plays an important role in anti-microbial defense, homeostasis and tissue repair. We are interested in IL-22 as it has the double function of suppressing or encouraging inflammation in various disease models including hepatic inflammation. As a survival factor for hepatocytes, IL-22 plays a protective role in many kinds of liver diseases, such as hepatitis, liver fibrosis, or hepatocellular carcinoma (HCC) by binding to the receptors IL-22R1 and IL-10R2. Overexpression of IL-22 reduces liver fibrosis by attenuating the activation of hepatic stellate cell (the main cell types involved in hepatic fibrosis), and down-regulating the levels of inflammatory cytokines. Administration of exogenous IL-22 increases the replication of hepatocytes by inhibiting cell apoptosis and promoting mitosis, ultimately plays a contributing role in liver regeneration. Furthermore, treatment with IL-22 activates hepatic signal transducer and activator of transcription 3 (STAT3), ameliorates hepatic oxidative stress and alcoholic fatty liver, effectively alleviate the liver damage caused by alcohol and toxicant. In conclusion, the hepatoprotective functions and liver regeneration promoting effect of IL-22 suggests the therapeutic potential of IL-22 in the treatment of human hepatic diseases.

Interleukin-22 acts as a mitochondrial protector

Interleukin (IL)-22 has been increasingly recognized as a promising therapeutic option for various types of diseases. This commentary summarizes the novel mechanistic aspects of IL-22 for the treatment of liver diseases including the study by Chen et al. published in the recent issue of the Theranostics that elucidated the novel function of IL-22 as a mitochondrial protector for the adaptive defense against liver injury.

Fibroblast Growth Factor-21 ameliorates hepatic encephalopathy by activating the STAT3-SOCS3 pathway to inhibit activated hepatic stellate cells

Neurological dysfunction, one of the consequences of acute liver failure (ALF), and also referred to as hepatic encephalopathy (HE), contributes to mortality posing challenges for clinical management. FGF21 has been implicated in the inhibition of cognitive decline and fibrogenesis. However, the effects of FGF21 on the clinical and molecular presentations of HE has not been elucidated. HE was induced by fulminant hepatic failure using thioacetamide (TAA) in male C57BL/6J mice while controls were injected with saline. For two consecutive weeks, mice were treated intraperitoneally with FGF21 (3 mg/kg) while controls were treated with saline. Cognitive, neurological, and activity function scores were recorded. Serum, liver, and brain samples were taken for analysis of CCL5 and GABA by ELISA, and RT qPCR was used to measure the expressions of fibrotic and pro-inflammatory markers. We report significant improvement in both cognitive and neurological scores by FGF21 treatment after impairment by TAA. GABA and CCL5, key factors in the progression of HE were also significantly reduced in the treatment group. Furthermore, the expression of fibrotic markers such as TGFβ and Col1 were also significantly downregulated after FGF21 treatment. TNFα and IL-6 were significantly reduced in the liver while in the brain, TNFα and IL-1 were downregulated. However, both in the liver and the brain, IL-10 was significantly upregulated. FGF21 inhibits CXCR4/CCL5 activation and upregulates the production of IL-10 in the damaged liver stimulating the production pro-inflammatory cytokines and apoptosis of hepatic stellate cells through the STAT3-SOCS3 pathway terminating the underlying fibrosis in HE.

Liver regeneration and alcoholic liver disease

Alcoholic liver diseases (ALD) are a wide spectrum of liver diseases caused by excessive alcohol consumption, from steatosis to cirrhosis. The pathogenesis of ALD is insufficiently understood, but mainly involves oxidative stress, inflammation, bacterial translocation, cell death, and impaired regeneration. Despite numerous attempts to improve patient prognosis, the treatment of advanced ALD is still based on abstinence, brief exposure to corticosteroids, or liver transplantation. However, poor response to corticosteroids and the shortage of liver donors leaves patients helpless towards the end stages. Advances in basic research have contributed to a better understanding of ALD pathophysiology, which offers new options for treatment. In recent years, several therapies related to liver regeneration have been tested with promising prospects, including molecule-induced liver regeneration, stem cell transplantation, and full-function 3D artificial liver assembly. This review discusses mechanisms underlying ALD that can be considered therapeutic targets for regeneration-based treatments.

Recent advances in alcohol-related liver disease (ALD): summary of a Gut round table meeting

Alcohol-related liver disease (ALD), which includes a range of disorders of different severity and is one of the most prevalent types of liver disease worldwide, has recently regained increased attention. Among other reasons, the realisation that any alcohol intake, regardless of type of beverage represents a health risk, and the new therapeutic strategies tested in recently published or undergoing clinical trials spur scientific interest in this area.In April 2019, Gut convened a round table panel of experts during the European Association for the Study of the Liver International Liver Congress in Vienna to discuss critical and up-to-date issues and clinical trial data regarding ALD, its epidemiology, diagnosis, management, pathomechanisms, possible future treatments and prevention. This paper summarises the discussion and its conclusions.

Reparative T lymphocytes in organ injury

Acute organ injuries such as acute cerebrovascular accidents, myocardial infarction, acute kidney injury, acute lung injury, and others are among the leading causes of death worldwide. Dysregulated or insufficient organ repair mechanisms limit restoration of homeostasis and contribute to chronic organ failure. Studies reveal that both humans and mice harness potent non-stem cells that are capable of directly or indirectly promoting tissue repair. Specific populations of T lymphocytes have emerged as important reparative cells with context-specific actions. These T cells can resolve inflammation and secrete reparative cytokines and growth factors as well as interact with other immune and stromal cells to promote the complex and active process of tissue repair. This Review focuses on the major populations of T lymphocytes known to mediate tissue repair, their reparative mechanisms, and the diseases in which they have been implicated. Elucidating and harnessing the mechanisms that promote the reparative functions of these T cells could greatly improve organ dysfunction after acute injury.

Safety, pharmacokinetics, and biomarkers of F-652, a recombinant human interleukin-22 dimer, in healthy subjects

F-652 is a recombinant fusion protein consisting of two human interleukin-22 (IL-22) molecules linked to an immunoglobulin constant region (IgG2-Fc). IL-22 plays critical roles in promoting tissue repair and suppressing bacterial infection. The safety, pharmacokinetics (PK), tolerability, and biomarkers of F-652 were evaluated following a single dose in healthy male volunteers in a randomized, double-blind, placebo-controlled study. Following single-dose subcutaneous (SC) injection of F-652 at 2.0 µg/kg into healthy subjects, six out of six subjects experienced delayed injection site reactions, which presented as erythematous and/or discoid eczematous lesions 10 to 17 days post-dosing. F-652 was then administered to the healthy subjects via an intravenous (IV) infusion at 2.0, 10, 30, and 45 µg/kg. No severe adverse event (SAE) was observed during the study. Among the IV-dosed cohorts, eye and skin treatment emergent adverse events (TEAEs) were observed in the 30 and 45 µg/kg cohorts. F-652 IV dosing resulted in linear increases in Cmax and AUC(0-t), and the T1/2 ranged from 39.4 to 206 h in the cohorts. An IV injection of F-652 induced dose-dependent increases in serum marker serum amyloid A, C-reactive protein, and FIB, and decreased serum triglycerides. The serum levels of 36 common pro-inflammatory cytokines/chemokines were not altered by the treatment of F-652 at 45 μg/kg. In conclusion, IV administration of F-652 to healthy male volunteers is safe and well-tolerated and demonstrates favorable PK and pharmacodynamic properties. These results warrant further clinical development of F-652 to treat inflammatory diseases.

Blueberry, combined with probiotics, alleviates non-alcoholic fatty liver disease via IL-22-mediated JAK1/STAT3/BAX signaling

Non-alcoholic fatty liver disease (NAFLD) is one of the most prevalent diseases worldwide. Blueberry, combined with probiotics (BP), might be a potential candidate for NAFLD treatment, due to its anti-inflammatory and anti-apoptotic properties. Here, we investigated whether the anti-inflammatory cytokine, IL-22, was involved in the therapeutic process of BP, using cell and rat models of NAFLD. Results indicated that BP significantly reduced lipid droplets and triglyceride (TG) accumulation in NAFLD cells. However, when IL-22 was deficient, the lipid droplets and TG content were significantly increased. In vivo, the serum parameters and pathological degree of NAFLD rats were significantly improved by BP, while IL-22 silencing significantly abolished the BP effect. Immunohistochemistry, immunofluorescence, qRT-PCR, and western blotting showed that the NAFLD group expressed significantly lower levels of IL-22, JAK1, and STAT3, and higher levels of BAX, than the normal group. Furthermore, BP significantly elevated the levels of IL-22, JAK1 and STAT3, and reduced the level of BAX in NAFLD, while IL-22 silencing prevented BP from restoring the expression of JAK1, STAT3, and BAX. We conclude that IL-22 is vital for the therapeutic effect of BP, and acts via activation of JAK1/STAT3 signaling and inhibition of the apoptosis factor BAX, which makes IL-22 a promising target for therapy of NAFLD.

Zhuang Gu Guan Jie Wan: Reasonable Application Can Alleviate the Liver Injury for Osteoarthritis Treatment

The potential toxicity of herbal drugs, particularly drug-induced liver injury (DILI), has received extensive attention as the use of Chinese herbal medicine has rapidly increased globally. As a classic Chinese patent medicine, Zhuang Gu Guan Jie Wan (ZGGJW) has been brought into focus recently because of its satisfactory therapeutic effects on osteoarthritis (OA) as well as its unanticipated side effects. This study aimed to decipher the puzzling phenomenon of liver injury developing in response to ZGGJW that varies by the subtype of OA. Normal, anterior cruciate ligament transaction (ACLT) and partial medial meniscectomy (MMx) induced OA and ovariectomy combined with ACLT and partial MMx induced rat models were used and treated orally with ZGGJW or distilled water for 30 days. The results from histopathology, biochemistry, and immunohistochemistry showed that ZGGJW induced liver injury, increased the level of malondialdehyde (MDA), and decreased the levels of total antioxidation capability (T-AOC), superoxide dismutase (SOD), interleukin-22 (IL-22), and signal transducer and activator of transcription factor 3 (STAT3) in the liver of normal rats, while liver injury was alleviated and showed different tendencies in the above markers for ACLT and partial MMx induction rats and ovariectomy combined with ACLT and partial MMx induction rats after ZGGJW treatment. In the OA disease states, hepatic injury induced by ZGGJW could be associated with an impairment in antioxidant capacity and the high levels of IL-22 and STAT3 after ZGGJW treatment may be responsible for the slight hepatic injury of ZGGJW based on the subtype of OA. This study provides a novel approach to better understanding of the risks and limitations when using potentially toxic Chinese patent medicine in clinical applications.

Alcoholic liver disease: A current molecular and clinical perspective

Heavy alcohol use is the cause of alcoholic liver disease (ALD). The ALD spectrum ranges from alcoholic steatosis to steatohepatitis, fibrosis, and cirrhosis. In Western countries, approximately 50% of cirrhosis-related deaths are due to alcohol use. While alcoholic cirrhosis is no longer considered a completely irreversible condition, no effective anti-fibrotic therapies are currently available. Another significant clinical aspect of ALD is alcoholic hepatitis (AH). AH is an acute inflammatory condition that is often comorbid with cirrhosis, and severe AH has a high mortality rate. Therapeutic options for ALD are limited. The established treatment for AH is corticosteroids, which improve short-term survival but do not affect long-term survival. Liver transplantation is a curative treatment option for alcoholic cirrhosis and AH, but patients must abstain from alcohol use for 6 months to qualify. Additional effective therapies are needed. The molecular mechanisms underlying ALD are complex and have not been fully elucidated. Various molecules, signaling pathways, and crosstalk between multiple hepatic and extrahepatic cells contribute to ALD progression. This review highlights established and emerging concepts in ALD clinicopathology, their underlying molecular mechanisms, and current and future ALD treatment options.

Enhanced Regeneration and Hepatoprotective Effects of Interleukin 22 Fusion Protein on a Predamaged Liver Undergoing Partial Hepatectomy

Liver ischemia-reperfusion injury (IRI) and regeneration deficiency are two major challenges for surgery patients with chronic liver disease. As a survival factor for hepatocytes, interleukin 22 (IL-22) plays an important role in hepatoprotection and the promotion of regeneration after hepatectomy. In this study, we aim to investigate the roles of an interleukin 22 fusion protein (IL-22-FP) in mice with a predamaged liver after a two-third partial hepatectomy (PHx). Predamaged livers in mice were induced by concanavalin A (ConA)/carbon tetrachloride (CCl4) following PHx with or without IL-22-FP treatment. A hepatic IRI mouse model was also used to determine the hepatoprotective effects of IL-22-FP. In the ConA/CCl4 model, IL-22-FP treatment alleviated liver injury and accelerated hepatocyte proliferation. Administration of IL-22-FP activated the hepatic signal transducer and activator of transcription 3 (STAT3) and upregulated the expression of many mitogenic proteins. IL-22-FP treatment prior to IRI effectively reduced liver damage through decreased aminotransferase and improved liver histology. In conclusion, IL-22-FP promotes liver regeneration in mice with predamaged livers following PHx and alleviates IRI-induced liver injury. Our study suggests that IL-22-FP may represent a promising therapeutic drug against regeneration deficiency and liver IRI in patients who have undergone PHx.