Role of gut bacterial and non-bacterial microbiota in alcohol-associated liver disease: Molecular mechanisms, biomarkers, and therapeutic prospective

The role of gut microbiota, exosomes, and their interaction in the pathogenesis of ALD

BACKGROUND

The liver disorders caused by alcohol abuse are termed alcoholic-related liver disease (ALD), including alcoholic steatosis, alcoholic steatohepatitis alcoholic hepatitis, and alcoholic cirrhosis, posing a significant threat to human health. Currently, ALD pathogenesis has not been completely clarified, which is likely to be related to the direct damage caused by alcohol and its metabolic products, oxidative stress, gut dysbiosis, and exosomes.

AIMS

The existing studies suggest that both the gut microbiota and exosomes contribute to the development of ALD. Moreover, there exists an interaction between the gut microbiota and exosomes. We discuss whether this interaction plays a role in the pathogenesis of ALD and whether it can be a potential therapeutic target for ALD treatment.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Chronic alcohol intake alters the diversity and composition of gut microbiota, which greatly contributes to ALD's progression. Some approaches targeting the gut microbiota, including probiotics, fecal microbiota transplantation, and phage therapy, have been confirmed to effectively ameliorate ALD in many animal experiments and/or several clinical trials. In ALD, the levels of exosomes and the expression profile of microRNA have also changed, which affects the pathogenesis of ALD. Moreover, there is an interplay between exosomes and the gut microbiota, which also putatively acts as a pathogenic factor of ALD.

Microbiome as a biomarker and therapeutic target in pancreatic cancer

Studying the effects of the microbiome on the development of different types of cancer has recently received increasing research attention. In this context, the microbial content of organs of the gastrointestinal tract has been proposed to play a potential role in the development of pancreatic cancer (PC). Proposed mechanisms for the pathogenesis of PC include persistent inflammation caused by microbiota leading to an impairment of antitumor immune surveillance and altered cellular processes in the tumor microenvironment. The limited available diagnostic markers that can currently be used for screening suggest the importance of microbial composition as a non-invasive biomarker that can be used in clinical settings. Samples including saliva, stool, and blood can be analyzed by 16 s rRNA sequencing to determine the relative abundance of specific bacteria. Studies have shown the potentially beneficial effects of prebiotics, probiotics, antibiotics, fecal microbial transplantation, and bacteriophage therapy in altering microbial diversity, and subsequently improving treatment outcomes. In this review, we summarize the potential impact of the microbiome in the pathogenesis of PC, and the role these microorganisms might play as biomarkers in the diagnosis and determining the prognosis of patients. We also discuss novel treatment methods being used to minimize or prevent the progression of dysbiosis by modulating the microbial composition. Emerging evidence is supportive of applying these findings to improve current therapeutic strategies employed in the treatment of PC.

The Protective Effect of Auricularia cornea var. Li. Polysaccharide on Alcoholic Liver Disease and Its Effect on Intestinal Microbiota

This study's objective was to examine the protective effect and mechanism of a novel polysaccharide (AYP) from Auricularia cornea var. Li. on alcoholic liver disease in mice. AYP was extracted from the fruiting bodies of Auricularia cornea var. Li. by enzymatic extraction and purified by DEAE-52 and Sephacryl S-400. Structural features were determined using high-performance liquid chromatography, ion exchange chromatography and Fourier-transform infrared analysis. Additionally, alcoholic liver disease (ALD) mice were established to explore the hepatoprotective activity of AYP (50, 100 and 200 mg/kg/d). Here, our results showed that AYP presented high purity with a molecular weight of 4.64 × 105 Da. AYP was composed of galacturonic acid, galactose, glucose, arabinose, mannose, xylose, rhamnose, ribos, glucuronic acid and fucose (molar ratio: 39.5:32.9:23.6:18.3:6.5:5.8:5.8:3.3:2:1.1). Notably, AYP remarkably reduced liver function impairment (alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), total cholesterol (TC)), nitric oxide (NO) and malondialdehyde (MDA) of the liver and enhanced the activity of antioxidant enzymes (superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and glutathione (gGSH)) in mice with ALD. Meanwhile, the serum level of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) were reduced in ALD mice treated by AYP. Furthermore, the AYPH group was the most effective and was therefore chosen to further investigate its effect on the intestinal microbiota (bacteria and fungi) of ALD mice. Based on 16s rRNA and ITS-1 sequencing data, AYP influenced the homeostasis of intestinal microbiota to mitigate the damage of ALD mice, possibly by raising the abundance of favorable microbiota (Muribaculaceae, Lachnospiraceae and Kazachstania) and diminishing the abundance of detrimental microbiota (Lactobacillus, Mortierella and Candida). This discovery opens new possibilities for investigating physiological activity in A. cornea var. Li. and provides theoretical references for natural liver-protecting medication research.

The protective effect of Nostoc commune Vauch. polysaccharide on alcohol-induced acute alcoholic liver disease and gut microbiota disturbance in mice

BACKGROUND

In recent years, the incidence of alcoholic liver disease (ALD) has gradually increased, the development of ALD is attached great attentions. Nostoc commune Vauch. polysaccharide (NCVP) is beneficial to maintain the gut health, but the protective effect of NCVP on the liver has not been reported yet.

PURPOSE

To study the protective effect and the underlying mechanisms of NCVP on ALD, a mouse model of acute ALD was established.

STUDY DESIGN AND METHODS

We built an acute ALD mouse model and explored the protective effect of NCVP through the detection of cytokines, histological examination, determination of short chain fatty acids, and 16S rRNA analysis of gut microbiota.

RESULTS

NCVP had hepatoprotective effects on acute alcohol-induced mice by improving antioxidant capacity, reducing oxidative stress and the serum cytokine levels (IL-1β, IL-6, and TNF-α). Simultaneously, histopathological changes in liver indicated that NCVP could inhibit local hepatocyte necrosis, cytoplasmic vacuolation and inflammatory cell infiltration induced by alcohol. NCVP also increased the level of total short-chain fatty acids of acute ALD mice. In addition, NCVP could significantly decrease the Firmicutes/Bacteroidetes ratio and the abundance of Patescibacteria, Helicobacter, and Actinomycetes and increase the abundance of Lachospiraceae, Prevotellaceae-UCG-003, Lactobacillaceae, and Desulfovibrio.

CONCLUSION

Our study proved that NCVP had in vivo hepatoprotective effect on acute ALD mice and provided scientific evidences that NCVP might be a promising drug candidate for the prevention and treatment of ALD.

Prognostic value of primary tumor location in colorectal cancer: an updated meta-analysis

The clinical, histological, and molecular differences between right-sided colon cancer (RCC) and left-sided colon cancer (RCC) have received considerable attention. Over the past decade, many articles have been published concerning the association between primary tumor location (PTL) of colorectal cancer and survival outcomes. Therefore, there is a growing need for an updated meta-analysis integrating the outcomes of recent studies to determine the prognostic role of right vs left-sidedness of PTL in patients with colorectal cancer. We conducted a comprehensive database review using PubMed, SCOPUS, and Cochrane library databases from February 2016 to March 2023 for prospective or retrospective studies reporting data on overall survival (OS) and cancer-specific survival (CSS) of RCC compared with LCC. A total of 60 cohort studies comprising 1,494,445 patients were included in the meta-analysis. We demonstrated that RCC is associated with a significantly increased risk of death compared with LCC by 25% (hazard ratio (HR), 1.25; 95% confidence interval (CI), 1.19-1.31; I2 = 78.4%; Z = 43.68). Results showed that patients with RCC have a worse OS compared with LCC only in advanced stages (Stage III: HR, 1.275; 95% CI 1.16-1.4; P = 0.0002; I2 = 85.8%; Stage IV: HR, 1.34; 95% CI 1.25-1.44; P < 0.0001; I2 = 69.2%) but not in primary stages (Stage I/II: HR, 1.275; 95% CI 1.16-1.4; P = 0.0002; I2 = 85.8%). Moreover, a meta-analysis of 13 studies including 812,644 patients revealed that there is no significant difference in CSS between RCC and LCC (HR, 1.121; 95% CI 0.97-1.3; P = 0.112). Findings from the present meta-analysis highlight the importance of PTL in clinical decision-making for patients with CRC, especially in advanced stages. We provide further evidence supporting the hypothesis that RCC and LCC are distinct disease entities that should be managed differently.

Bioinformatics analysis and machine learning approach applied to the identification of novel key genes involved in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) comprises a range of chronic liver diseases that result from the accumulation of excess triglycerides in the liver, and which, in its early phases, is categorized NAFLD, or hepato-steatosis with pure fatty liver. The mortality rate of non-alcoholic steatohepatitis (NASH) is more than NAFLD; therefore, diagnosing the disease in its early stages may decrease liver damage and increase the survival rate. In the current study, we screened the gene expression data of NAFLD patients and control samples from the public dataset GEO to detect DEGs. Then, the correlation betweenbetween the top selected DEGs and clinical data was evaluated. In the present study, two GEO datasets (GSE48452, GSE126848) were downloaded. The dysregulated expressed genes (DEGs) were identified by machine learning methods (Penalize regression models). Then, the shared DEGs between the two training datasets were validated using validation datasets. ROC-curve analysis was used to identify diagnostic markers. R software analyzed the interactions between DEGs, clinical data, and fatty liver. Ten novel genes, including ABCF1, SART3, APC5, NONO, KAT7, ZPR1, RABGAP1, SLC7A8, SPAG9, and KAT6A were found to have a differential expression between NAFLD and healthy individuals. Based on validation results and ROC analysis, NR4A2 and IGFBP1b were identified as diagnostic markers. These key genes may be predictive markers for the development of fatty liver. It is recommended that these key genes are assessed further as possible predictive markers during the development of fatty liver.

Alcohol and the Brain-Gut Axis: The Involvement of Microglia and Enteric Glia in the Process of Neuro-Enteric Inflammation

Binge or chronic alcohol consumption causes neuroinflammation and leads to alcohol use disorder (AUD). AUD not only affects the central nervous system (CNS) but also leads to pathologies in the peripheral and enteric nervous systems (ENS). Thus, understanding the mechanism of the immune signaling to target the effector molecules in the signaling pathway is necessary to alleviate AUD. Growing evidence shows that excessive alcohol consumption can activate neuroimmune cells, including microglia, and change the status of neurotransmitters, affecting the neuroimmune system. Microglia, like peripheral macrophages, are an integral part of the immune defense and represent the reticuloendothelial system in the CNS. Microglia constantly survey the CNS to scavenge the neuronal debris. These cells also protect parenchymal cells in the brain and spinal cord by repairing nerve circuits to keep the nervous system healthy against infectious and stress-derived agents. In an activated state, they become highly dynamic and mobile and can modulate the levels of neurotransmitters in the CNS. In several ways, microglia, enteric glial cells, and macrophages are similar in terms of causing inflammation. Microglia also express most of the receptors that are constitutively present in macrophages. Several receptors on microglia respond to the inflammatory signals that arise from danger-associated molecular patterns (DAMPs), pathogen-associated molecular patterns (PAMPs), endotoxins (e.g., lipopolysaccharides), and stress-causing molecules (e.g., alcohol). Therefore, this review article presents the latest findings, describing the roles of microglia and enteric glial cells in the brain and gut, respectively, and their association with neurotransmitters, neurotrophic factors, and receptors under the influence of binge and chronic alcohol use, and AUD.

The effects of low-fat dairy products fortified with 1500 IU vitamin D3 on serum liver function biomarkers in adults with abdominal obesity: a randomized controlled trial

INTRODUCTION

Vitamin D deficiency has been reported to affect liver function biomarkers. This study was aimed to investigate the effect of consuming vitamin D fortified low-fat dairy products on liver function tests in adults with abdominal obesity.

METHODS

This total blinded randomized controlled trial was undertaken on otherwise healthy abdominally obese adults living in Mashhad, Iran. Milk and yogurt were fortified with 1500 IU vitamin D3 nano-capsules. Participants were randomized to receive fortified milk (n = 73), plain milk (n = 73), fortified yogurt (n = 69), and plain yogurt (n = 74) for 10 weeks. Blood samples were taken at baseline and at the end of the study to assess serum levels of vitamin D, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase (ALP), and Gamma glutamyl transferase.

RESULTS

A total of 289 participants completed the study (54% female). The groups were homogenous in terms of age, sex, weight, energy intake, and physical activity level (p-value > 0.05). After the trial, vitamin D serum levels were significantly increased in both groups receiving fortified products (both p < 0.001). There was a significant time*group effect only in serum ALP (p < 0.001).

CONCLUSION

Consumption of dairy products fortified by 1500 IU vitamin D3 might have detrimental effects on serum levels of some liver enzymes in individuals with abdominal obesity. Further studies needed to determine these effects and underlying mechanisms.

TRIAL REGISTRATION

IRCT20101130005280N27 .

High-dose vitamin D supplementation is related to an improvement in serum alkaline phosphatase in COVID-19 patients; a randomized double-blinded clinical trial

BACKGROUND

The benefits and harms of vitamin D supplementation in the treatment of COVID-19 have not yet been fully documented. In this study, we aimed to evaluate the effects of high-dose vitamin D supplementation on liver function tests in COVID-19.

METHOD

This double-blinded randomized clinical trial was conducted on 140 hospitalized patients aged > 30 years. Patients were randomly allocated to receive either intervention group (n = 70 receiving 50,000 IU of vitamin D capsules orally as a single dose and then 10,000 IU syrup daily from the second day of admission for 30 days) and the control group (n = 70 receiving 1000 IU vitamin D syrup orally per day). Liver function tests (LFT), including alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), and Lactate Dehydrogenase (LDH) were evaluated at baseline and at the end of the intervention. Decision tree analysis was performed to identify the predictors for change in liver enzymes.

RESULTS

Among COVID-19 patients, a significant decrease was observed in serum level of ALP between intervention and placebo groups (p = 0.04). In addition, decision tree analysis revealed that GGT, temperature, serum magnesium level at baseline and gender were the most important predictors of ALT changes in COVID-19 patients.

CONCLUSION

High-dose vitamin D supplementation improved ALP markers among COVID-19 patients. More randomized controlled trials with longer follow-up times will be required.

Difference and clinical value of metabolites in plasma and feces of patients with alcohol-related liver cirrhosis

BACKGROUND

Alterations in plasma and intestinal metabolites contribute to the pathogenesis and progression of alcohol-related liver cirrhosis (ALC).

AIM

To explore the common and different metabolites in the plasma and feces of patients with ALC and evaluate their clinical implications.

METHODS

According to the inclusion and exclusion criteria, 27 patients with ALC and 24 healthy controls (HCs) were selected, and plasma and feces samples were collected. Liver function, blood routine, and other indicators were detected with automatic biochemical and blood routine analyzers. Liquid chromatography-mass spectrometry was used to detect the plasma and feces metabolites of the two groups and the metabolomics of plasma and feces. Also, the correlation between metabolites and clinical features was analyzed.

RESULTS

More than 300 common metabolites were identified in the plasma and feces of patients with ALC. Pathway analysis showed that these metabolites are enriched in bile acid and amino acid metabolic pathways. Compared to HCs, patients with ALC had a higher level of glycocholic acid (GCA) and taurocholic acid (TCA) in plasma and a lower level of deoxycholic acid (DCA) in the feces, while L-threonine, L-phenylalanine, and L-tyrosine increased simultaneously in plasma and feces. GCA, TCA, L-methionine, L-phenylalanine, and L-tyrosine in plasma were positively correlated with total bilirubin (TBil), prothrombin time (PT), and maddrey discriminant function score (MDF) and negatively correlated with cholinesterase (CHE) and albumin (ALB). The DCA in feces was negatively correlated with TBil, MDF, and PT and positively correlated with CHE and ALB. Moreover, we established a P/S BA ratio of plasma primary bile acid (GCA and TCA) to fecal secondary bile acid (DCA), which was relevant to TBil, PT, and MDF score.

CONCLUSION

The enrichment of GCA, TCA, L-phenylalanine, L-tyrosine, and L-methionine in the plasma of patients with ALC and the reduction of DCA in feces were related to the severity of ALC. These metabolites may be used as indicators to evaluate the progression of alcohol-related liver cirrhosis.

Integrated analysis of multi-omics data for the discovery of biomarkers and therapeutic targets for colorectal cancer

The considerable burden of colorectal cancer and the rising trend in young adults emphasize the necessity of understanding its underlying mechanisms, providing new diagnostic and prognostic markers, and improving therapeutic approaches. Precision medicine is a new trend all over the world and identification of novel biomarkers and therapeutic targets is a step forward towards this trend. In this context, multi-omics data and integrated analysis are being investigated to develop personalized medicine in the management of colorectal cancer. Given the large amount of data from multi-omics approach, data integration and analysis is a great challenge. In this Review, we summarize how statistical and machine learning techniques are applied to analyze multi-omics data and how it contributes to the discovery of useful diagnostic and prognostic biomarkers and therapeutic targets. Moreover, we discuss the importance of these biomarkers and therapeutic targets in the clinical management of colorectal cancer in the future. Taken together, integrated analysis of multi-omics data has great potential for finding novel diagnostic and prognostic biomarkers and therapeutic targets, however, there are still challenges to overcome in future studies.

A Thermodynamic and Kinetic Study on Electrochemical Esterification in Aroma-Enhanced Distilled Liquor (Baijiu)

The development of low-alcohol Baijiu is consistent with demand for the industry’s sustainable development. However, the ester aroma of low-alcohol Baijiu is insipid and unstable—mainly due to the hydrolysis of esters during shelf life—thus reducing the industry scale of low-alcohol Baijiu to a significantly small range. An electrochemical method for improving low-alcohol Baijiu’s ester concentration and stability was investigated from the aspects of thermodynamics and kinetics. The key finding is that the new Baijiu’s ester content obtained through distillation is relatively high, exceeding its content in the thermodynamic equilibrium state. Thus, the ester will be hydrolyzed during shelf life. The idea of applying electrochemical catalytic esterification technology to the production of low-alcohol Baijiu in this study is directly derived from the production practice of Baijiu factories; it provides a direction for the further optimization of low-alcohol Baijiu to facilitate the production of an alternative product that will contribute to public health.

Bioactive Peptides: Potential Impact on the Treatment of Gastrointestinal Cancers

We have reviewed the potential use of bioactive peptides in the treatment of gastrointestinal (GI) malignancies, which are a significant cause of morbidity and mortality globally. Conventional therapies, such as surgery, chemotherapy, and radiotherapy, are associated with numerous side effects that may lead to longterm complications. Bioactive peptides are short-chain amino acids that can be extracted from natural sources or synthesized, and they have various potential health benefits, including anti-inflammatory, anti-hypertensive, antioxidant, antimicrobial, and anti-cancer properties. Bioactive peptides can be acquired from animal or plant sources, and can be classified based on their function, such as ACE-inhibiting, antimicrobial, and electrolyte- regulating peptides. Recent studies have demonstrated the promising role of bioactive peptides in tumor suppression, especially when combined with conventional therapies. In this study, we have reviewed the beneficial properties of bioactive peptides and their role in suppressing tumor activity. The mechanisms of bioactive peptides in tumor suppression are discussed. We have further reviewed the findings of preclinical and clinical studies that have investigated the application of bioactive peptides in the treatment of GI cancers. This review highlights the potential use of bioactive peptides as a promising treatment method for GI malignancies to increase the quality of life of GI cancer patients.

Lactobacillus plantarum J26 Alleviating Alcohol-Induced Liver Inflammation by Maintaining the Intestinal Barrier and Regulating MAPK Signaling Pathways

Alcoholic liver disease (ALD), as a global health problem, is mainly caused by liver inflammation. Meanwhile, probiotics have been considered as a potential and promising strategy to prevent and alleviate ALD. This study aimed to investigate the ameliorative effect of pre-intaking with Lactobacillus plantarum J26 (L. plantarum J26) on alcohol-induced liver inflammation, with emphasis on the underlying mechanism for alleviating ALD. The results indicated that L. plantarum J26 could reduce the abundance of Gram-negative pathogenic bacteria by regulating the gut microbiota in mice with alcoholic liver injury, thereby reducing the lipopolysaccharide (LPS) content in the intestine. In addition, L. plantarum J26 could also maintain the intestinal barrier, prevent LPS from crossing the intestinal barrier to correct disorders of the gut-liver axis and then inhibit the activation of Toll-like receptor 4 (TLR4)-mediated MAPK signaling pathway, reducing liver inflammation and restoring liver functions. In conclusion, pre-intake of L. plantarum J26 could alleviate alcohol-induced liver inflammation, which may be closely related to the role of intestinal microbiota in regulating and maintaining the intestinal barrier and then regulating the MAPK signaling pathway.

Can probiotic, prebiotic, and synbiotic supplementation modulate the gut-liver axis in type 2 diabetes? A narrative and systematic review of clinical trials

Background

Type 2 diabetes, one of the most common noncommunicable diseases, is a metabolic disorder that results in failed homeostatic control in several body systems, including hepatic function. Due to the gut microbiome’s potential role in diabetes’ pathogenesis, prebiotics, probiotics, and synbiotics have been proposed as complimentary therapeutic approaches aimed at microbiota readjustment.

Methods

A systematic review was conducted on PubMed, Scopus, Web of Science, Embase, and the Cochrane Library examining the effect of probiotics, prebiotics, and synbiotics on hepatic biomarkers in patients with diabetes.

Results

From 9,502 search hits, 10 studies met the inclusion criteria and were included in this review. A total of 816 participants (460 intervention and 356 control) were investigated for the effects of nine different hepatic biomarker measurements including aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total protein, bilirubin, liver steatosis, liver stiffness, fatty liver index, and gamma-glutamyl transferase levels. Of the 13 intervention groups analyzed from the 10 studies, 3 were prebiotic interventions, 3 were single species probiotic interventions, 3 were multi-species probiotic interventions, and 4 were synbiotic interventions. Nutraceuticals used in these trials included six genera of bacteria (Lactobacillus, Bifidobacterium, Streptococcus, Acetobacter, Lactococcus, and Propionibacterium), five different prebiotic formulations (inulin, inulin and beta carotene, chicory inulin enriched with oligofructose, galacto-oligosaccharides syrup, and powdered cinnamon), or a combination of these to form multi-species probiotics or synbiotics.

Conclusion

Although some studies showed insignificant changes in hepatic biomarkers, generally the results yielded a decrease in liver damage due to reduced oxidative stress, pro-inflammatory cytokines, gut dysbiosis, and insulin resistance which led to improvements in hepatic biomarker levels.

Advancements in the Alcohol-Associated Liver Disease Model

Alcohol-associated liver disease (ALD) is an intricate disease that results in a broad spectrum of liver damage. The presentation of ALD can include simple steatosis, steatohepatitis, liver fibrosis, cirrhosis, and even hepatocellular carcinoma (HCC). Effective prevention and treatment strategies are urgently required for ALD patients. In previous decades, numerous rodent models were established to investigate the mechanisms of alcohol-associated liver disease and explore therapeutic targets. This review provides a summary of the latest developments in rodent models, including those that involve EtOH administration, which will help us to understand the characteristics and causes of ALD at different stages. In addition, we discuss the pathogenesis of ALD and summarize the existing in vitro models. We analyse the pros and cons of these models and their translational relevance and summarize the insights that have been gained regarding the mechanisms of alcoholic liver injury.