Alcohol-Related Liver Disease: Novel Insights into Mechanism.

Metallothionein-dependent recovery of alcohol-related liver injury by zinc-glutathione.

Alcohol-related liver disease (ALD) is one of the leading causes of alcohol-related morbidity and mortality worldwide. Unfortunately, limited therapeutic options are currently available, due to the complex risk factors involved as well as the lack of information on the molecular mechanisms driving its progression. Interestingly, chronic, excessive alcohol intake has been reported to exacerbate the severity of Obstructive sleep apnea (OSA), a respiratory disorder typically characterized by chronic intermittent hypoxia (CIH). However, this relationship between alcohol-enhanced OSA and ALD development/progression remains to be elucidated. As an approach to investigate this relationship in vivo Gao-binge ALD and CIH mouse models were established. Alcohol-related liver injury, hepatic steatosis, inflammation and oxidative stress were then assessed in these models. In addition, LPS and ethanol-co-treated AML12 hepatocytes served as an in vitro model to investigate the mechanisms through which CIH affects ethanol-induced liver injury. CIH intervention ameliorated alcohol-related liver injury, reduced hepatic lipid accumulation and oxidative stress and alleviated liver inflammation. Mechanistically, in the liver of these Gao-binge mice, CIH intervention inhibited alcohol-induced upregulation and activation of hypoxia-inducible factor 2α (HIF-2α), a protein which plays a key role in hepatic lipid metabolism and liver injury. Similar to these effects observed in response to CIH intervention, treatment of Gao-binge mice with the selective inhibitor of HIF-2α, PT2385, alleviated alcohol-related liver injury and steatosis while inhibiting oxidative stress and inflammation. Additional findings from our in vitro model revealed that CIH downregulated HIF-2α by promoting calpains protein expression, thereby reducing the accumulation of lipid droplets and decreasing ROS production in AML12 cells co-challenged with LPS and ethanol. The above results provide important, new evidence that re-conceptualizes the role of alcohol-enhanced OSA in ALD progression. Moreover, these findings can serve as the foundation for the development of HIF-2α inhibitors for use in the prevention and treatment of ALD.

Enteric dysbiosis plays an essential role in the pathogenesis of alcoholic liver disease (ALD). Detailed characterization of the alterations in the gut microbiome is needed for understanding their pathogenic role in ALD and developing effective therapeutic approaches using probiotic supplementation. Mice were fed liquid Lieber-DeCarli diet without or with alcohol (5% v/v) for 6 weeks. A subset of mice were administered the probiotic Lactobacillus rhamnosus GG (LGG) from 6 to 8 weeks. Indicators of intestinal permeability, hepatic steatosis, inflammation and injury were evaluated. Metagenomic analysis of the gut microbiome was performed by analyzing the fecal DNA by amplification of the V3–V5 regions of the 16S rRNA gene and large-scale parallel pyrosequencing on the 454 FLX Titanium platform. Chronic ethanol feeding caused a decline in the abundance of both Bacteriodetes and Firmicutes phyla, with a proportional increase in the gram negative Proteobacteria and gram positive Actinobacteria phyla; the bacterial genera that showed the biggest expansion were the gram negative alkaline tolerant Alcaligenes and gram positive Corynebacterium. Commensurate with the qualitative and quantitative alterations in the microbiome, ethanol caused an increase in plasma endotoxin, fecal pH, hepatic inflammation and injury. Notably, the ethanol-induced pathogenic changes in the microbiome and the liver were prevented by LGG supplementation. Overall, significant alterations in the gut microbiome over time occur in response to chronic alcohol exposure and correspond to increases in intestinal barrier dysfunction and development of ALD. Moreover, the altered bacterial communities of the gut may serve as significant therapeutic target for the prevention/treatment of chronic alcohol intake induced intestinal barrier dysfunction and liver disease.

Alcohol is one of the three leading causes of liver disease in the developed world. Patients with alcohol-related liver disease are often cared for in general wards and hospitals, rather than specialist centres. This may be a result of the number of patients being admitted or a lack of referral to specialist services by healthcare professionals. The financial cost of caring for patients with alcohol-related injuries is continuing to rise. This article explores the mechanisms of liver injury caused by alcohol; the risk factors associated with alcohol-related liver disease; assessment tools used to identify patients with alcohol use disorders; withdrawal from alcohol; chronic liver disease; and issues surrounding transplantation. The importance of the nursing role in assessing and monitoring patients undergoing withdrawal from alcohol, information giving and advice on the prevention of alcohol-related liver injury, and supporting patients with alcohol-related liver injury is highlighted.

Apoptosis in alcoholic hepatitis: a novel therapeutic target?

Alcohol intake can modify gut microbiota composition, increase gut permeability, and promote liver fibrogenesis. LRP6 is a signal transmembrane protein and a co-receptor for the canonical Wnt signaling pathway. This study compared the curative effect of LRP6-CRISPR on alcohol-related liver injury with that of traditional fecal microbiota transplant (FMT) and investigated the alteration of the gut microbiome following the treatment. A rat model of alcohol-related liver injury was established and injected with lentiviral vectors expressing LRP6-CRISPR or administered with fecal filtrate from healthy rats, with healthy rat served as the control. Liver tissues of rats were examined by HE staining, Sirius staining, and Oil red O staining, respectively. The expression of LRP6 and fibrosis biomarkers were tested by PCR. The fecal sample of rats was collected and examined by 16S rRNA sequencing. Our data indicated that LRP6-CRISPR was more efficient in the prevention of alcohol-related liver injury than FMT. Microbiome analysis showed that alcohol-related liver injury related to gut microbiota dysbiosis, while treatment with LRP6-CRISPR or FMT increased gut microflora diversity and improved gut symbiosis. Further, bacteria specific to the disease stages were identified. Genera Romboutsia, Escherichia-Shigella, Pseudomonas, Turicibacter, and Helicobacter were prevalent in the intestine of rats with alcohol-related liver injury, while the domination of Lactobacillus was found in rats treated with LRP6-CRISPR or FMT. Besides, Lactobacillus and genera belonging to family Lachnospiraceae, Bacteroidales S24-7 group, and Ruminococcaceae were enriched in healthy rats. LRP6-CRISPR and FMT have beneficial effects on the prevention of alcohol-related liver injury, and correspondently, both treatments altered the disrupted gut microflora to a healthy one.

Alcoholic liver disease (ALD) is a major chronic liver disease. Chronic alcohol consumption induces dysbiosis, disruption of gut barrier function, oxidative stress, inflammation, and changes in lipid metabolism, thereby leading to ALD. In this study, we investigated whether the commercial Morinda citrifolia extract Nonitri can ameliorate ALD symptoms through the gut-liver axis. We used mice chronically administered EtOH and found a marked increase in serum endotoxin levels and biomarkers of liver pathology. Moreover, the EtOH-treated group showed significantly altered gut microbial composition particularly that of Alistipes, Bacteroides, and Muribaculum and disrupted gut barrier function. However, Nonitri improved serum parameters, restored the microbial proportions, and regulated levels of zonula occludens1, occludin, and claudin1. Furthermore, Nonitri suppressed inflammation by inhibiting endotoxin-triggered toll-like receptor 4-signaling pathway and fat deposition by reducing lipogenesis through activating AMP-activated protein kinase in the liver. Furthermore, Pearson's correlation analysis showed that gut microbiota and ALD-related markers were correlated, and Nonitri regulated these bacteria. Taken together, our results indicate that the hepatoprotective effect of Nonitri reduces endotoxin levels by improving gut health, and inhibits fat deposition by regulating lipid metabolism.

Verapamil Prevents Chronic Renal Failure-Induced Abnormalities in Lipid Metabolism

When specific gut microbes reveal a possible link between hepatic steatosis and adipose tissue

Alcohol-related liver disease (ALD) is a common indication for orthotopic liver transplantation (OLT) in adults. Although return to 'heavy drinking' post-OLT is believed to be uncommon, the prevalence and severity of alcohol-related liver injury in such patients is not well characterized. We retrospectively reviewed the records of 68 adult patients who underwent OLT for ALD to determine the incidence of return to heavy drinking and to assess their clinical outcome. Follow-up ranged from 8-99 months (mean 42) post-OLT; 54 patients were followed for > or = 12 months. Ten patients (15%) had evidence of coexisting viral hepatitis (hepatitis C in 9 and hepatitis B in 1) before OLT. Six of 68 patients (8%) returned to heavy drinking post-OLT, and three of those died of alcoholic hepatitis at nine months, 2.5 and 3.5 years after OLT. In two of these three patients, premortem liver biopsy showed histologic features of alcoholic hepatitis in addition to bridging fibrosis or cirrhosis. None of the three patients who died of ALD had coexisting viral hepatitis. Of the 57 patients surviving for > or = 3 months post-OLT, 4 of 8 patients (50%) with steatosis and Mallory bodies in their native livers returned to heavy drinking compared to only 2/49 (4%) without these histologic findings (P<0.05). In conclusion, the incidence of heavy drinking post-OLT was uncommon, however, it was associated with fatal alcoholic hepatitis in 50% of patients. Rapidly progressive alcohol-related liver injury was seen even in the absence of coexisting viral hepatitis. The presence of steatosis and Mallory bodies in the native liver, which suggests recent or ongoing alcohol-related liver injury, predicted a return to heavy drinking post-OLT.

To investigate the association of alcohol dose, duration of drinking and obesity with abnormal alcohol-related liver injury indicators, the prevalence of alcohol-related liver injury in the island population of China. Randomized multistage stratified cluster sampling from the island population of China was used in the population-based case-control study. Then interview, physical examination, laboratory assessments and ultrasonography were done. Daily alcohol intake > or = 20 g, duration of drinking > or = 5 years and obesity were closely related to alcohol-related liver injury (P < 0.05). The odds-ratio (OR) (95% CI) was 1.965 (1.122-3.442), 3.412 (1.789-6.507) and 1.887 (1.261-2.824), respectively. The prevalence rate of alcohol-related liver injury in > or = 20 g daily alcohol intake group and < 20 g daily alcohol intake group was 37.14% and 12.06%, respectively. The prevalence rate of alcohol-related liver injury in > or = 5 years drinking group and < 5 years drinking group was 34.44% and 8.53%, respectively. No significant dose-response relation was found between daily alcohol intake and abnormal alcohol-related liver injury indicators as well as between duration of drinking and abnormal alcohol-related liver injury indicators. There was no significant difference in the prevalence of alcohol-related liver injury between beer drinking group and yellow rice wine drinking group, hard liquor drinking group, multiple drinking group. The risk threshold of daily alcohol intake is 20 g and duration of drinking inducing alcohol-related liver injury 5 years in the island population of China. Liver injury induced by obesity should be concerned.

Recent studies have made significant advances in understanding the mechanisms of gut microbiota involved in human health and disease [1,2].Now the gut microbiota has been recognized as a key player in a broad spectrum of human diseases from obesity associated liver and cardiovascular diseases to mental development and psychiatric diseases [3,4].Accordingly, modulations of gut microbial diversity and composition are expected to improve human health and to provide novel therapeutic modalities for human disease.The gut microbial modulators can be simply specific diets and drinks, natural tea and Chinese herbs, or specialized prebiotics and probiotics.In this special issue, authors presented a number of very interesting studies on changes of gut microbiota in digestive diseases.These review and original articles of research and clinical studies cover a range of topics, including the pathogenesis of alcoholic and nonalcoholic fatty liver diseases (NAFLD), the outcome of intestinal bacterial translocation in advanced cirrhosis, the gut microbiota changes in an animal colitis model after treatment with a monoclonal antibody, and fecal microbiota transplantation (FMT) in elderly patients with refractory Clostridium difficile infection.In these articles, authors have described mechanisms of disease development as well as therapeutic effects of specific antibodies, probiotics, and FMT.While we know the simple cause of alcoholic fatty liver disease (AFLD), its pathogenesis is complicated and it

Tomato lycopene prevention of alcoholic fatty liver disease and hepatocellular carcinoma development

The Gut Microbiome in Health and Disease

BackgroundRecent studies identify that antimicrobial peptides (AMPs) function as immune‐regulators in addition to their antimicrobial property.as CRAMP is the murine ortholog of human LL‐37, the only known member of cathelicidin AMP family. Alcoholic liver disease (ALD) is characterized by gut dysbiosis and intestinal and hepatic inflammation. We previously showed a decreased expression of intestinal CRAMP in a mouse model of ALD, suggesting a potential role of CRAMP in ALD. Gut microbiota‐derived butyrate increases pancreatic CRAMP, which is important in regulating autoimmune diabetes. Here we aimed to test the hypothesis that CRAMP protects the liver and pancreas from alcohol‐induced organ damage by positively modifying the gut microbiota and inhibiting the pro‐inflammatory response.MethodsCRAMP KO and wild type (WT) mice were subjected to 5% alcohol liquid diet for 24 days and were gavaged with a bolus of alcohol (5g/kg) on the last day. Mice in control groups were fed an isocaloric maltose dextrin solution. Hepatic and pancreatic injury were examined by analyzing serum samples and histological analysis. Mouse fecal samples were collected for metagenomic and metabolomics study. Mouse macrophage Raw 264.7 cells were used to determine the effect of synthetic CRAMP on LPS‐induced inflammatory activation. Results were further examined in CRAMP deficient mouse peritoneal macrophages and bone marrow derived macrophages.ResultsSerum levels of ALT and AST significantly increased by alcohol in both groups but more pronounced in CRAMP KO mice. Alcohol induced an increased and distinct zonal distributed hepatic fat accumulation in CRAMP KO mice compared to WT mice. Furthermore, CRAMP KO mice had increased pro‐inflammatory and decreased anti‐inflammatory cytokines compared to WT mice. In addition, the marker of pancreatitis, serum amylase activity was elevated in CRAMP KO mice, but not in WT mice. Microbiota analysis in mouse fecal samples showed a difference in the abundance of Firmicutes and Bacteroidetes phyla after alcohol exposure between two groups. Metabolomics study showed that major fecal concentrations of short chain fatty acids (SCFAs), in particular, butyric acid, were significantly lower in the CRAMP KO mice than in the WT mice. In vitro study using RAW 264.7 cells demonstrated that sodium salt of butyric acid (NaB) and synthetic CRAMP peptide significantly inhibited LPS‐induced pro‐inflammatory cytokines production in a dose dependent manner, partially through the inhibition of NLRP3 inflammasome activation. Interestingly, ex vivo study demonstrated a reduction of LPS induced IL‐1b expression in CRAMP deficient peritoneal macrophages compared to those from WT mice, suggesting that other compensatory pathways may exist to offset the deleterious effects of CRAMP deficiency.ConclusionsCRAMP deficiency exacerbates ALD and alcoholic pancreatitis through gut dysbiosis associated decrease in SCFAs and increased hepatic and systemic inflammation. Synthetic CRAMP peptide inhibits endotoxin‐associated inflammasome activation. CRAMP signaling may represent a therapeutic approach for ALD and alcoholic pancreatitis.Support or Funding InformationSupported by grants from NIH and Veterans AdministrationThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.