ABSTRACT: Alcoholic liver disease (ALD) is a major cause of morbidity and mortality worldwide. In developed countries, ALD is a major cause of end-stage liver disease that requires transplantation. The spectrum of ALD includes simple steatosis, alcoholic hepatitis, ?brosis, cirrhosis, and hepatocellular carcinoma. Alcohol abstinence is the most effective therapy for ALD. However, targeted therapies are urgently needed for patients with severe ALD (i.e., alcoholic hepatitis) or those who do not abstain from alcohol. The lack of studies and the availability of animal models that do not reflect all the features of this disease in humans inhibit the development of new drugs for ALD. In ALD-associated fibrosis, hepatic stellate cells are the principal cell type responsible for extracellular matrix production. Although the mechanisms underlying fibrosis in ALD are largely similar to those observed in other chronic liver diseases, oxidative stress, methionine metabolism abnormalities, hepatocyte apoptosis, and endotoxin lipopolysaccharides that activate Kupffer cells may play unique roles in disease-related fibrogenesis. Lipogenesis during the early stages of ALD has recently been implicated as a risk factor for the progression of cirrhosis. Other topics include osteopontin, interleukin-1 signaling, and genetic polymorphism. In this review, we discuss the basic pathogenesis of ALD and focus on liver fibrogenesis.
Project description:Alcoholic liver disease (ALD) represents a spectrum of injury, ranging from simple steatosis to alcoholic hepatitis to cirrhosis. Regular alcohol use results in fatty changes in the liver which can develop into inflammation, fibrosis and ultimately cirrhosis with continued, excessive drinking. Alcoholic hepatitis (AH) is an acute hepatic inflammation associated with significant morbidity and mortality that can occur in patients with steatosis or underlying cirrhosis. The pathogenesis of ALD is multifactorial and in addition to genetic factors, alcohol-induced hepatocyte damage, reactive oxygen species, gut-derived microbial components result in steatosis and inflammatory cell (macrophage and neutrophil leukocyte) recruitment and activation in the liver. Continued alcohol and pro-inflammatory cytokines induce stellate cell activation and result in progressive fibrosis. Other than cessation of alcohol use, medical therapy of AH is limited to prednisolone in a subset of patients. Given the high mortality of AH and the progressive nature of ALD, there is a major need for new therapeutic intervention for this underserved patient population.
Project description: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.
Project description:Alcoholic liver disease (ALD) is a leading cause of morbidity and mortality worldwide. Alcoholic fatty liver disease can progress to steatohepatitis, alcoholic hepatitis, fibrosis, and cirrhosis. Patients with alcohol abuse show quantitative and qualitative changes in the composition of the intestinal microbiome. Furthermore, patients with ALD have increased intestinal permeability and elevated systemic levels of gut-derived microbial products. Maintaining eubiosis, stabilizing the mucosal gut barrier, or preventing cellular responses to microbial products protect from experimental ALD. Therefore, intestinal dysbiosis and pathological bacterial translocation appear fundamental for the pathogenesis of ALD. This review highlights causes for intestinal dysbiosis and pathological bacterial translocation, their relationship, and consequences for ALD. We also discuss how the liver affects the intestinal microbiota.
Project description:The following review article presents clinical and experimental features of alcohol-induced liver disease (ALD). Basic aspects of alcohol metabolism leading to the development of liver hepatotoxicity are discussed. ALD includes fatty liver, acute alcoholic hepatitis with or without liver failure, alcoholic steatohepatitis (ASH) leading to fibrosis and cirrhosis, and hepatocellular cancer (HCC). ALD is fully attributable to alcohol consumption. However, only 10-20% of heavy drinkers (persons consuming more than 40 g of ethanol/day) develop clinical ALD. Moreover, there is a link between behaviour and environmental factors that determine the amount of alcohol misuse and their liver disease. The range of clinical presentation varies from reversible alcoholic hepatic steatosis to cirrhosis, hepatic failure, and hepatocellular carcinoma. We aimed to (1) describe the clinico-pathology of ALD, (2) examine the role of immune responses in the development of alcoholic hepatitis (ASH), (3) propose diagnostic markers of ASH, (4) analyze the experimental models of ALD, (5) study the role of alcohol in changing the microbiota, and (6) articulate how findings in the liver and/or intestine influence the brain (and/or vice versa) on ASH; (7) identify pathways in alcohol-induced organ damage and (8) to target new innovative experimental concepts modeling the experimental approaches. The present review includes evidence recognizing the key toxic role of alcohol in ALD severity. Cytochrome p450 CYP2E1 activation may change the severity of ASH. The microbiota is a key element in immune responses, being an inducer of proinflammatory T helper 17 cells and regulatory T cells in the intestine. Alcohol consumption changes the intestinal microbiota and influences liver steatosis and liver inflammation. Knowing how to exploit the microbiome to modulate the immune system might lead to a new form of personalized medicine in ALF and ASH.
Project description:Background and aims: Liver is a major target organ for alcohol-induced disease and the spectrum of pathological states elicited by alcohol in liver comprises steatosis, alcoholic steatohepatitis, progressive fibrosis and cirrhosis, conditions that may progress to hepatocellular carcinoma. Many experimental animal models of alcoholic steatohepatitis exist that vary in duration, mode of alcohol administration and the degree and types of liver injury produced. While most of these models, regardless whether alcohol is administered through liquid diet or intragastrically, produce steatohepatitis and mild fibrosis, it is widely acknowledged that these models fail to fully recapitulate key characteristics of severe forms of alcoholic liver disease, such as alcoholic hepatitis. Recent studies attempted to combine alcohol and fibrosis and achieved promising results in mouse models that achieve some of the key features of alcoholic liver disease accompanied by exacerbated fibrosis and acute renal injury. This study combined a chronic cholestatic liver fibrosis model induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) with a mouse model of intragastric alcohol feeding. Methods: Adult male C57BL6/J mice were treated with 3,5-diethoxycarbonyl-1,4-dihydrocolidine (DDC) containing diet (0.05% w/w) to induce chronic liver fibrosis. Following DDC-induced fibrogenesis, ethyl alcohol (EtOH) (up to 27 g/ kg/day, up to 28 days) was administered continuously to mice via a gastric feeding tube (Tsukamoto-Frenchmodel of alcoholic liver disease). Results: Exposure to DDC or EtOH alone resulted in liver fibrosis or steatosis, respectively. Combined treatment with DDC and EtOH lead to an additive effect on liver injury, as evident by the development of hepatic inflammation, steatosis, and pericellular fibrosis, and by increased serum transaminase levels, compared to mice treated with either agent alone. Liver transcriptomic changes specific to combined treatment group included pathways involved in the cell cycle and DNA damage. Analyses of feces from these mice revealed alcohol-associated changes to the bile acid profile and gut microbiome. Conclusions: Mice treated with DDC and EtOH displayed several key characteristics of human alcoholic hepatitis, including pericellular fibrosis, increased hepatic bacterial load with dysbiosis, reduced capacity of the microbiome to synthesize secondary bile acids. Overall design: Animal model of acute-on-chronic alcoholic hepatitis
Project description:Alcoholic liver disease (ALD) represents a spectrum of disorders, ranging from simple steatosis to severe alcoholic hepatitis and cirrhosis. The severe form of ALD comprises multiple problems in the liver, including inflammation, hepatocellular damage, fibrosis, and impaired liver regeneration, and likely requires combinational therapies. In this review, we discuss recently identified therapeutic targets that inhibit inflammation, ameliorate hepatocyte death, and promote liver repair in ALD, with a focus on our recent studies on the immunosuppressive drug prednisolone and the hepatoprotective cytokine interleukin-22. Clinical trials examining prednisolone plus interleukin-22 therapy for severe alcoholic hepatitis are currently under consideration.
Project description:Alcoholic liver disease (ALD) is a leading cause of cirrhosis, liver cancer, and acute and chronic liver failure and as such causes significant morbidity and mortality. While alcohol consumption is slightly decreasing in several European countries, it is rising in others and remains high in many countries around the world. The pathophysiology of ALD is still incompletely understood but relates largely to the direct toxic effects of alcohol and its main intermediate, acetaldehyde. Recently, novel putative mechanisms have been identified in systematic scans covering the entire human genome and raise new hypotheses on previously unknown pathways. The latter also identify host genetic risk factors for significant liver injury, which may help design prognostic risk scores. The diagnosis of ALD is relatively easy with a panel of well-evaluated tests and only rarely requires a liver biopsy. Treatment of ALD is difficult and grounded in abstinence as the pivotal therapeutic goal; once cirrhosis is established, treatment largely resembles that of other etiologies of advanced liver damage. Liver transplantation is a sound option for carefully selected patients with cirrhosis and alcoholic hepatitis because relapse rates are low and prognosis is comparable to other etiologies. Still, many countries are restrictive in allocating donor livers for ALD patients. Overall, few therapeutic options exist for severe ALD. However, there is good evidence of benefit for only corticosteroids in severe alcoholic hepatitis, while most other efforts are of limited efficacy. Considering the immense burden of ALD worldwide, efforts of medical professionals and industry partners to develop targeted therapies in ALF has been disappointingly low.
Project description:Alcoholic liver disease (ALD) comprises a clinical-histologic spectrum including fatty liver, alcoholic hepatitis (AH), and cirrhosis with its complications. Most patients are diagnosed at advanced stages and data on the prevalence and profile of patients with early disease are limited. Diagnosis of ALD requires documentation of chronic heavy alcohol use and exclusion of other causes of liver disease. Prolonged abstinence is the most effective strategy to prevent disease progression. AH presents with rapid onset or worsening of jaundice, and in severe cases may transition to acute on chronic liver failure when the risk for mortality, depending on the number of extra-hepatic organ failures, may be as high as 20-50% at 1 month. Corticosteroids provide short-term survival benefit in about half of treated patients with severe AH and long-term mortality is related to severity of underlying liver disease and is dependent on abstinence from alcohol. General measures in patients hospitalized with ALD include inpatient management of liver disease complications, management of alcohol withdrawal syndrome, surveillance for infections and early effective antibiotic therapy, nutritional supplementation, and treatment of the underlying alcohol-use disorder. Liver transplantation, a definitive treatment option in patients with advanced alcoholic cirrhosis, may also be considered in selected patients with AH cases, who do not respond to medical therapy. There is a clinical unmet need to develop more effective and safer therapies for patients with ALD.
Project description:In recent years, there has been a plethora of attempts to discover biomarkers that are more reliable than ?-fetoprotein for the early prediction and prognosis of hepatocellular carcinoma (HCC). Efforts have involved such fields as genomics, transcriptomics, epigenetics, microRNA, exosomes, proteomics, glycoproteomics, and metabolomics. HCC arises against a background of inflammation, steatosis, and cirrhosis, due mainly to hepatic insults caused by alcohol abuse, hepatitis B and C virus infection, adiposity, and diabetes. Metabolomics offers an opportunity, without recourse to liver biopsy, to discover biomarkers for premalignant liver disease, thereby alerting the potential of impending HCC. We have reviewed metabolomic studies in alcoholic liver disease (ALD), cholestasis, fibrosis, cirrhosis, nonalcoholic fatty liver (NAFL), and nonalcoholic steatohepatitis (NASH). Specificity was our major criterion in proposing clinical evaluation of indole-3-lactic acid, phenyllactic acid, N-lauroylglycine, decatrienoate, N-acetyltaurine for ALD, urinary sulfated bile acids for cholestasis, cervonoyl ethanolamide for fibrosis, 16?-hydroxyestrone for cirrhosis, and the pattern of acyl carnitines for NAFL and NASH. These examples derive from a large body of published metabolomic observations in various liver diseases in adults, adolescents, and children, together with animal models. Many other options have been tabulated. Metabolomic biomarkers for premalignant liver disease may help reduce the incidence of HCC.
Project description:Alcoholic liver disease (ALD), a disorder caused by excessive alcohol consumption is a global health issue. More than two billion people consume alcohol in the world and about 75 million are classified as having alcohol disorders. ALD embraces a wide spectrum of hepatic lesions including steatosis, alcoholic steatohepatitis (ASH), fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). ALD is a complex disease where environmental, genetic, and epigenetic factors contribute to its pathogenesis and progression. The severity of alcohol-induced liver disease depends on the amount, method of usage and duration of alcohol consumption as well as on age, gender, presence of obesity, and genetic susceptibility. Genome-wide association studies and candidate gene studies have identified genetic modifiers of ALD that can be exploited as non-invasive biomarkers, but which do not completely explain the phenotypic variability. Indeed, ALD development and progression is also modulated by epigenetic factors. The premise of this review is to discuss the role of genetic variants and epigenetic modifications, with particular attention being paid to microRNAs, as pathogenic markers, risk predictors, and therapeutic targets in ALD.