Role of Nutrition in Alcoholic Liver Disease: Summary of the Symposium at the ESBRA 2017 Congress

Ellagic Acid Protects against Alcohol-Related Liver Disease by Modulating the Hepatic Circadian Rhythm Signaling through the Gut Microbiota-NPAS2 Axis

Alcohol-related liver disease (ALD) encompasses a spectrum of hepatic disorders resulting from alcohol abuse, which constitutes the predominant etiology of morbidity and mortality associated with hepatic pathologies globally. Excessive alcohol consumption disrupts the integrity of the intestinal barrier and perturbs the balance of gut microbiota, thereby facilitating the progression of ALD. Ellagic acid (EA) has been extensively reported to be an effective intervention for alleviating liver symptoms. However, the target molecules of EA in improving ALD and its underlying mechanism remain elusive. First, our study indicates that EA ameliorated ALD through the hepatic circadian rhythm signaling by up-regulating neuronal PAS domain protein 2 (NPAS2). Furthermore, analysis of the intestinal microbiome showed that EA significantly enhanced the abundance of beneficial bacteria, which was positively correlated with NPAS2 expression and negatively correlated with liver injury. Finally, antibiotic treatment and fecal microbiota transplantation (FMT) experiments established a causal relationship between the reshaped microbiota and NPAS2 in the amelioration of ALD. In summary, our study demonstrates novel evidence that EA attenuated ALD by modulating the hepatic circadian rhythm signaling pathway via the gut microbiota-NPAS2 axis, providing valuable insights for EA and microbiome-targeted interventions against ALD.

Oenothein B ameliorates hepatic injury in alcoholic liver disease mice by improving oxidative stress and inflammation and modulating the gut microbiota

Introduction

Alcoholic liver disease (ALD) is a global health problem for which there is no current food and drug administration (FDA)-approved therapy. Oenothein B (OEB) is a macrocyclic dimer ellagic tannin that possesses abundant biological activities including antioxidant, anti-inflammation, antitumor, immunomodulatory, and antimicrobial properties.

Materials and methods

In this study, the hepatoprotective effect of OEB against ALD was investigated in vivo and in vitro.

Results

We found that OEB treatment dramatically reduced alcohol-induced hepatic injury, as evidenced by decreased levels of aminotransferases and inflammatory biomarkers and increased antioxidant capacity in OEB-treated groups.

Discussion

OEB treatment alleviated oxidative stress by upregulating the Keap1/Nrf2 signaling pathway and inhibited inflammation by downregulating the TLR4/NF-κB signaling pathway. Additionally, OEB treatment positively improved alcohol-induced intestinal microbial dysbiosis by modulating the structure and composition of gut microbiota. Interestingly, we observed the increasement of short-chain fatty acid (SCFA) producers (Muribaculaceae) and the decreasement of Gram-negative bacteria (Akkermansia) in the OEB treatment groups, which may contribute to the inhibition of hepatic oxidative stress and inflammation via the gut-liver axis. In summary, our findings indicate that OEB is a promising therapeutic strategy for preventing and treating ALD.

Time Course RNA-seq Reveals Soybean Responses against Root-Lesion Nematode and Resistance Players

Pratylenchus brachyurus causes serious damage to soybean production and other crops worldwide. Plant molecular responses to RLN infection remain largely unknown and no resistance genes have been identified in soybean. In this study, we analyzed molecular responses to RLN infection in moderately resistant BRSGO (Chapadões-BRS) and susceptible TMG115 RR (TMG) Glycine max genotypes. Differential expression analysis revealed two stages of response to RLN infection and a set of differentially expressed genes (DEGs) in the first stage suggested a pattern-triggered immunity (PTI) in both genotypes. The divergent time-point of DEGs between genotypes was observed four days post-infection, which included the activation of mitogen-activated protein kinase (MAPK) and plant-pathogen interaction genes in the BRS, suggesting the occurrence of an effector-triggered immunity response (ETI) in BRS. The co-expression analyses combined with single nucleotide polymorphism (SNP) uncovered a key element, a transcription factor phytochrome-interacting factor (PIF7) that is a potential regulator of moderate resistance to RLN infection. Two genes for resistance-related leucine-rich repeat (LRR) proteins were found as BRS-specific expressed genes. In addition, alternative splicing analysis revealed an intron retention in a myo-inositol oxygenase (MIOX) transcript, a gene related to susceptibility, may cause a loss of function in BRS.

Preventive and therapeutic role of betaine in liver disease: A review on molecular mechanisms

Betaine is a kind of water-soluble quaternary amine-type alkaloid widely existing in food, such as wheat germ, beet, spinach, shrimp and wolfberry. As an important methyl donor and osmotic pressure regulator in human body, betaine plays an important role in a variety of physiological activities. In recent years, a large number of literatures have shown that betaine has good preventive and therapeutic effects on many liver diseases, including chemical or drug-induced liver injury, nonalcoholic fatty liver disease, alcoholic fatty liver disease, liver fibrosis, hepatitis B and hepatitis C. Therefore, by searching the databases of Web of Science, PubMed, SciFinder and CNKI, this paper has summarized the molecular mechanisms of betaine in improving liver diseases. The results show that the improvement of liver diseases by betaine is closely related to a variety of molecular mechanisms, including inhibition of inflammatory response, improvement of insulin resistance, reduction of endoplasmic reticulum stress, alleviation of liver oxidative stress, increase of autophagy, remodeling of intestinal flora and regulation of epigenetic modification. More importantly, nuclear transcription factor kappa (NF-κB), AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor α/γ (PPAR-α/γ), liver X receptor α (LXRα), protein kinase B (Akt), toll-like receptor 4 (TLR4) and cysteinyl aspartate specific proteinase-3 (Caspase-3) signaling pathways are considered as important molecular targets for betaine to improve liver diseases. These important findings will provide a direction and basis for further exploring the pathogenesis of various liver diseases and tapping the potential of betaine in the clinical treatment.

Beneficial Effects of Betaine: A Comprehensive Review

Medicinal herbs and many food ingredients possess favorable biological properties that contribute to their therapeutic activities. One such natural product is betaine, a stable, nontoxic natural substance that is present in animals, plants, and microorganisms. Betaine is also endogenously synthesized through the metabolism of choline or exogenously consumed through dietary intake. Betaine mainly functions as (i) an osmolyte and (ii) a methyl-group donor. This review describes the major physiological effects of betaine in whole-body health and its ability to protect against both liver- as well as non-liver-related diseases and conditions. Betaine's role in preventing/attenuating both alcohol-induced and metabolic-associated liver diseases has been well studied and is extensively reviewed here. Several studies show that betaine protects against the development of alcohol-induced hepatic steatosis, apoptosis, and accumulation of damaged proteins. Additionally, it can significantly prevent/attenuate progressive liver injury by preserving gut integrity and adipose function. The protective effects are primarily associated with the regulation of methionine metabolism through removing homocysteine and maintaining cellular SAM:SAH ratios. Similarly, betaine prevents metabolic-associated fatty liver disease and its progression. In addition, betaine has a neuroprotective role, preserves myocardial function, and prevents pancreatic steatosis. Betaine also attenuates oxidant stress, endoplasmic reticulum stress, inflammation, and cancer development. To conclude, betaine exerts significant therapeutic and biological effects that are potentially beneficial for alleviating a diverse number of human diseases and conditions.

Lactobacillus plantarum KLDS1.0344 and Lactobacillus acidophilus KLDS1.0901 Mixture Prevents Chronic Alcoholic Liver Injury in Mice by Protecting the Intestinal Barrier and Regulating Gut Microbiota and Liver-Related Pathways

Health and wellbeing are significantly impaired by alcoholic liver disease (ALD), and although some lactic acid bacteria strains have been shown previously to relieve ALD symptoms, the mechanisms behind these effects are still unclear. Here, the Lieber-DeCarli liquid diet containing alcohol was fed to C57BL/6J mice for 6 weeks to build a chronic alcoholic liver lesion model to study the protective effects and possible mechanisms of Lactobacillus mixture (Lactobacillus plantarum KLDS1.0344 and Lactobacillus acidophilus KLDS1.0901). The results showed that Lactobacillus mixture improved intestinal epithelial permeability and reduced the serum lipopolysaccharide (LPS) levels. Furthermore, Lactobacillus mixture inhibited liver lipid accumulation, oxidative stress, and inflammation by regulating AMPK, Nrf-2, and TLR4/NF-κB pathways. Importantly, the Lactobacillus mixture modulated the gut microbiota, resulting in increased short-chain fatty acid (SCFA) producers and decreased Gram-negative bacteria. Taken together, these findings indicated that the Lactobacillus mixture could positively regulate the gut microbiota, causing increased levels of SCFAs, which inhibited alcohol-induced liver lipid accumulation and oxidative stress through the gut-liver axis. Moreover, following administration of the Lactobacillus mixture, the improvement of intestinal epithelial permeability and the reduction of Gram-negative bacteria led to the decrease of LPS entering the portal vein, thereby inhibiting alcohol-induced liver inflammation.

Second hits exacerbate alcohol-related organ damage: an update

Chronic and excessive alcohol abuse cause direct and indirect detrimental effects on a wide range of body organs and systems and accounts for ~4% of deaths worldwide. Many factors influence the harmful effects of alcohol. This concise review presents newer insights into the role of select second hits in influencing the progression of alcohol-induced organ damage by synergistically acting to generate a more dramatic downstream biological defect. This review specifically addresses on how a lifestyle factor of high fat intake exacerbates alcoholic liver injury and its progression. This review also provides the mechanistic insights into how increasing matrix stiffness during liver injury promotes alcohol-induced fibrogenesis. It also discusses how hepatotropic viral (HCV, HBV) infections as well as HIV (which is traditionally not known to be hepatotropic), are potentiated by alcohol exposure to promote hepatotoxicity and fibrosis progression. Finally, this review highlights the impact of reactive aldehydes generated during alcohol and cigarette smoke coexposure impair innate antimicrobial defense and increased susceptibility to infections. This review was inspired by the symposium held at the 17th Congress of the European Society for Biomedical research on Alcoholism in Lille, France entitled 'Second hits in alcohol-related organ damage'.

Susceptibility of Asialoglycoprotein Receptor-Deficient Mice to Lps/Galactosamine Liver Injury and Protection by Betaine Administration

BACKGROUND

Work from our laboratory has shown that the ethanol-induced increase in apoptotic hepatocellular death is closely related to the impairment in the ability of the asialoglycoprotein receptor (ASGP-R) to remove neighboring apoptotic cells. In this study, we assessed the role of ASGP-R in fulminant liver failure and investigated whether prior treatment with betaine (a naturally occurring tertiary amine) is protective.

METHODS

Lipopolysaccharide (LPS; 50 μg/kg BW) and galactosamine (GalN; 350 mg/kg BW) were injected together to wild-type and ASGP-R-deficient mice that were treated for two weeks prior with or without 2% betaine in drinking water. The mice were sacrificed 1.5, 3, or 4.5 h post-injection, and tissue samples were collected.

RESULTS

LPS/GalN injection generate distinct molecular processes, which includes increased production of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), thus causing apoptosis as evident by increased caspase-3 activity. ASGP-R deficient animals showed increased liver caspase activities, serum TNF-α and IL-6 levels, as well as more pronounced liver damage compared with the wild-type control animals after intraperitoneal injection of LPS/GalN. In addition, prior administration of betaine was found to significantly attenuate the LPS/GalN-induced increases in liver injury parameters.

CONCLUSION

Our work underscores the importance of normal functioning of ASGP-R in preventing severe liver damage and signifies a therapeutic role of betaine in prevention of liver injuries from toxin-induced fulminant liver failure.

GanMeijian ameliorates lipid accumulation and oxidative damage in alcoholic fatty liver disease in Wistar rats

Alcoholic fatty liver disease (AFLD), a major public health problem, has drawn clinical and scientific attention. The study aims to investigate the effect of Ganmeijian [crude extract of malt root, phosphoesterase complex (Pho)] on AFLD, and explore the possible mechanisms. An AFLD rat model was made. 30 and 60 mg/kg Pho were administrated through intestinal fistula for 5 weeks. Compared with those in model group, AST, LDL-C and TC in 30 mg/kg Pho group and TC in 60 mg/kg Pho group decreased. The mRNA level of Fas, Gpat1 and Srebp-1c in Pho groups was significantly reduced. The level of GSH-Px was increased, mitochondrial activity was improved, and the level of MDA and ROS was reduced in Pho groups. Pho shows a beneficial effect on AFLD. The mechanisms are possibly related to Pho inhibiting the expression of fat synthesis genes, protecting the function and increasing the activity of mitochondria in hepatocytes, then reducing the accumulation of ROS and the level of oxidative stress in the liver.

Comparative Transcriptome Analyses Provide Potential Insights into the Molecular Mechanisms of Astaxanthin in the Protection against Alcoholic Liver Disease in Mice

Alcoholic liver disease (ALD) is a major cause of chronic liver disease worldwide. It is a complex process, including a broad spectrum of hepatic lesions from fibrosis to cirrhosis. Our previous study suggested that astaxanthin (AST) could alleviate the hepatic inflammation and lipid dysmetabolism induced by ethanol administration. In this study, a total of 48 male C57BL/6J mice were divided into 4 groups: a Con group (fed with a Lieber–DeCarli liquid diet), an AST group (fed with a Lieber–DeCarli liquid diet and AST), an Et group (fed with an ethanol-containing Lieber–DeCarli liquid diet), and a EtAST group (fed with an ethanol-containing Lieber–DeCarli liquid diet and AST). Then, comparative hepatic transcriptome analysis among the groups was performed by Illumina RNA sequencing. Gene enrichment analysis was conducted to identify pathways affected by the differentially expressed genes. Changes of the top genes were verified by quantitative real-time PCR (qRT-PCR) and Western blot. A total of 514.95 ± 6.89, 546.02 ± 15.93, 576.06 ± 21.01, and 690.85 ± 54.14 million clean reads were obtained for the Con, AST, Et, and EtAST groups, respectively. Compared with the Et group, 1892 differentially expressed genes (DEGs) (including 351 upregulated and 1541 downregulated genes) were identified in the AST group, 1724 differentially expressed genes (including 233 upregulated and 1491 downregulated genes) were identified in the Con group, and 1718 DEGs (including 1380 upregulated and 338 downregulated genes) were identified in the EtAST group. The enrichment analyses revealed that the chemokine signaling, the antigen processing and presentation, the nucleotide-binding and oligomerization domain (NOD)-like receptor signaling, and the Toll-like receptor signaling pathways enriched the most differentially expressed genes. The findings of this study provide insights for the development of nutrition-related therapeutics for ALD.

Liver Transplantation for Alcoholic Liver Disease: An Update

Alcoholic liver disease is a serious and increasing contributor to the global liver disease burden. Extensive selection criteria, including a minimum abstinence period, has previously been used to secure good outcomes but new research questions the effectiveness of abstinence periods and has recommended changes in integrated alcohol use treatment to effectively prevent relapse. Patients have unique health concerns, including posttransplantation risks of malignancy and metabolic complications, but overall very good long-term outcomes. Severe alcoholic hepatitis has been increasingly treated with early transplantation without a set sobriety period, with overall favorable outcomes, even with respect to recidivism.