Microbiome Alterations in Alcohol Use Disorder and Alcoholic Liver Disease

Baseline gut microbiome and metabolites are correlated with changes in alcohol consumption in participants in a randomized Zonisamide clinical trial

Development and severity of alcohol use disorder (AUD) has been linked to variations in gut microbiota and their associated metabolites in both animal and human studies. However, the involvement of the gut microbiome in alcohol consumption of individuals with AUD undergoing treatment remains unclear. To address this, stool samples (n = 32) were collected at screening (baseline) and trial completion from a double-blind, placebo-controlled trial of zonisamide in individuals with AUD. Alcohol consumption was measured both at baseline and endpoint of 16-week trial period. Fecal microbiome was analyzed via 16 S rRNA sequencing and metabolome via untargeted LC-MS. Both sex (p = 0.003) and psychotropic medication usage (p = 0.025) are associated with baseline microbiome composition. The relative abundance of 11 genera at baseline was correlated with percent drinking reduction (p.adj < 0.1). Overall microbiome community structure at baseline differed between high and low reducers of alcohol drinking (67-100% and 0-33% drinking reduction, respectively; p = 0.034). A positive relationship between baseline fecal GABA levels and percent drinking reduction (R = 0.43, p.adj < 0.07) was identified by microbiome function prediction and confirmed by ELISA and metabolomics. Metabolomics analysis also found 3-hydroxykynurenine, a neurotoxic intermediate metabolite of tryptophan, was negatively correlated with drinking reduction (p.adj = 0.047), and was over-represented in low reducers. These findings highlight importance of baseline microbiome and amino acid metabolites in drinking reduction in AUD participants undergoing zonisamide treatment. It may hold significant value as a predictive tool in clinical settings to better personalize intervention and improve reduction in alcohol consumption in future.

Regulatory mechanisms of the probiotic-targeted gut-liver axis for the alleviation of alcohol-related liver disease: a review

Alcohol abuse-triggered alcohol-related liver disease (ALD) has become as a global public health concern that substantially affects the well-being and clinical status of patients. Although modern medicine provides various treatments for ALD, their effectiveness is limited and can lead to adverse side effects. Probiotics have been employed to prevent, alleviate, and even treat ALD, with promising results. However, few comprehensive reviews are available on how they mitigate ALD by targeting the gut-liver axis. This review systematically clarifies the specific mediators of the gut-liver axis in healthy states. It also describes the alterations observed in ALD. Furthermore, this review thoroughly summarizes the underlying mechanisms through which probiotics act on the gut-liver axis to relieve ALD. It also discusses the current status and challenges faced in clinical research applications. Finally, we discuss the challenges and future prospects of using probiotics to treat ALD. This review improves our understanding of ALD and supports the development and application of probiotics that target the gut-liver axis for therapeutic use.

Liuweizhiji Gegen-Sangshen beverage protects against alcoholic liver disease in mice through the gut microbiota mediated SCFAs/GPR43/GLP-1 pathway

Introduction

Alcoholic liver disease (ALD) is a pathological state of the liver caused by longterm alcohol consumption. Recent studies have shown that the modulation of the gut microbiota and its metabolic products, specifically the short-chain fatty acids (SCFAs), exert a critical role in the evolution and progression of ALD. The Liuweizhiji Gegen-Sangshen beverage (LGS), as a functional beverage in China, is derived from a traditional Chinese herbal formula and has been clinically applied for ALD treatment, demonstrating significant efficacy. However, the underlying mechanisms of LGS for alleviating ALD involving gut microbiota regulation remain unknown.

Methods

In this study, an ALD murine model based on the National Institute on Alcohol Abuse and Alcoholism (NIAAA) method was established.

Results

The results showed that oral LGS treatment dose-dependently alleviated alcoholinduced liver injury and inflammation in mice through decreasing levels of ALT, AST and proinflammatory cytokines (TNF-α, IL-6, IL-1β). LGS significantly improved liver steatosis, enhanced activities of alcohol metabolizing enzymes (ALDH and ADH), and reduced the CYP2E1 activity. Notably, regarding most detected indices, the effect of LGS (particularly at medium and high dose) was comparable to the positive drug MTDX. Moreover, LGS had a favorable effect on maintaining intestinal barrier function through reducing epithelial injury and increasing expression of occludin. 16S rRNA sequencing results showed that LGS remarkably modulated gut microbiota structure in ALD mice via recovering alcohol-induced microbial changes and specifically mediating enrichment of several bacterial genera (Alloprevotella, Monoglobus, Erysipelatoclostridium Parasutterella, Harryflintia and unclassified_c_Clostridia). Further study revealed that LGS increased production of SCFAs of hexanoic acid in cecum, promoted alcohol-mediated reduction of GRP43 expression in ileum, and increased serum GLP-1 level.

Discussion

Overall, LGS exerts a remarkable protective effect on ALD mice through the gut microbiota mediated specific hexanoic acid production and GPR43/GLP-1 pathway.

Rifaximin alleviates irinotecan-induced diarrhea in mice model

BACKGROUND

Irinotecan is a chemotherapeutic drug widely used to treat solid tumors. However, its effectiveness is limited by the severely delayed onset of diarrhea. This study aimed to confirm the protective effects of the non-systemic oral antibiotic rifaximin on irinotecan-induced mucositis in mice model.

MATERIALS AND METHODS

Six to eight week-old BALB/c mice were treated with saline, irinotecan (50 mg/kg, i.p. once daily), rifaximin (50 mg/kg, p.o. twice daily), or irinotecan + rifaximin for 9 consecutive days. Signs of diarrhea, bloody diarrhea, and body weight were monitored daily. Intestinal tissues were harvested for histopathological analysis and quantitative PCR. SN38 and SN38G concentration in intestine were detected using LC-MS analysis. Intestinal bacteria β-glucuronidase (BGUS) activity was detected using mouse feces. We performed 16S rRNA sequencing to investigate the gut microbiota composition. Gut permeability was tested in vivo by measuring the fluorescein isothiocyanate-dextran intensity in the serum.

RESULTS

Rifaximin reduced the frequency of delayed diarrhea and attenuated the severity of diarrhea caused by irinotecan in mice. Rifaximin significantly inhibited SN38 exposure in intestine and irinotecan-induced increase in BGUS activity. Rifaximin alleviated intestinal mucosal inflammation, prevented intestinal epithelial damage caused by irinotecan, and maintained gut barrier function. Moreover, the consecutive use of rifaximin did not cause a disorder in gut microbiota and reduced irinotecan-induced Firmicutes expansion. More importantly, rifaximin inhibited the expansion of some microbiota (such as Blautia, Eggerthella, and f_Enterobacteriaceae) and promoted an increase in beneficial microbiota (such as Lactobacillus intestinalis, Lachnospiraceae NK4A136 group, and f_Oscillospiraceae).

CONCLUSIONS

Preventive use of rifaximin is a feasible method to protect against irinotecan-induced diarrhea.

Gut-liver axis: Recent concepts in pathophysiology in alcohol-associated liver disease

The growing recognition of the role of the gut microbiome's impact on alcohol-associated diseases, especially in alcohol-associated liver disease, emphasizes the need to understand molecular mechanisms involved in governing organ-organ communication to identify novel avenues to combat alcohol-associated diseases. The gut-liver axis refers to the bidirectional communication and interaction between the gut and the liver. Intestinal microbiota plays a pivotal role in maintaining homeostasis within the gut-liver axis, and this axis plays a significant role in alcohol-associated liver disease. The intricate communication between intestine and liver involves communication between multiple cellular components in each organ that enable them to carry out their physiological functions. In this review, we focus on novel approaches to understanding how chronic alcohol exposure impacts the microbiome and individual cells within the liver and intestine, as well as the impact of ethanol on the molecular machinery required for intraorgan and interorgan communication.

Gut Bacteria in Alcohol-Associated Liver Disease

Alcohol-associated liver disease (ALD) poses a significant global public health challenge, with high patient mortality rates and economic burden. The gut microbiome plays an important role in the onset and progression of alcohol-associated liver disease. Excessive alcohol consumption disrupts the intestinal barrier, facilitating the entry of harmful microbes and their products into the liver, exacerbating liver damage. Dysbiosis, marked by imbalance in gut bacteria, correlates with ALD severity. Promising microbiota-centered therapies include probiotics, phages, and fecal microbiota transplantation. Clinical trials demonstrate the potential of these interventions to improve liver function and patient outcomes, offering a new frontier in ALD treatment.

Dangers of the chronic stress response in the context of the microbiota-gut-immune-brain axis and mental health: a narrative review

More than 20% of American adults live with a mental disorder, many of whom are treatment resistant or continue to experience symptoms. Other approaches are needed to improve mental health care, including prevention. The role of the microbiome has emerged as a central tenet in mental and physical health and their interconnectedness (well-being). Under normal conditions, a healthy microbiome promotes homeostasis within the host by maintaining intestinal and brain barrier integrity, thereby facilitating host well-being. Owing to the multidirectional crosstalk between the microbiome and neuro-endocrine-immune systems, dysbiosis within the microbiome is a main driver of immune-mediated systemic and neural inflammation that can promote disease progression and is detrimental to well-being broadly and mental health in particular. In predisposed individuals, immune dysregulation can shift to autoimmunity, especially in the presence of physical or psychological triggers. The chronic stress response involves the immune system, which is intimately involved with the gut microbiome, particularly in the process of immune education. This interconnection forms the microbiota-gut-immune-brain axis and promotes mental health or disorders. In this brief review, we aim to highlight the relationships between stress, mental health, and the gut microbiome, along with the ways in which dysbiosis and a dysregulated immune system can shift to an autoimmune response with concomitant neuropsychological consequences in the context of the microbiota-gut-immune-brain axis. Finally, we aim to review evidenced-based prevention strategies and potential therapeutic targets.

Gut microbiome in alcohol use disorder: Implications for health outcomes and therapeutic strategies-a literature review

Alcohol use disorder (AUD) represents a major public health issue which affects millions of people globally and consist a chronic relapsing condition associated with substantial morbidity and mortality. The gut microbiome plays a crucial role in maintaining overall health and has emerged as a significant contributor to the pathophysiology of various psychiatric disorders. Recent evidence suggests that the gut microbiome is intimately linked to the development and progression of AUD, with alcohol consumption directly impacting its composition and function. This review article aims to explore the intricate relationship between the gut microbiome and AUD, focusing on the implications for mental health outcomes and potential therapeutic strategies. We discuss the bidirectional communication between the gut microbiome and the brain, highlighting the role of microbiota-derived metabolites in neuroinflammation, neurotransmission, and mood regulation. Furthermore, we examine the influence of AUD-related factors, such as alcohol-induced gut dysbiosis and increased intestinal permeability, on mental health outcomes. Finally, we explore emerging therapeutic avenues targeting the gut microbiome in the management of AUD, including prebiotics, probiotics, and fecal microbiota transplantation. Understanding the complex interplay between the gut microbiome and AUD holds promise for developing novel interventions that could improve mental health outcomes in individuals with AUD.

The Impact of Probiotic Bifidobacterium on Liver Diseases and the Microbiota

Recent studies have shown the promising potential of probiotics, especially the bacterial genus Bifidobacterium, in the treatment of liver diseases. In this work, a systematic review was conducted, with a focus on studies that employed advanced Next Generation Sequencing (NGS) technologies to explore the potential of Bifidobacterium as a probiotic for treating liver pathologies such as Non-Alcoholic Fatty Liver Disease (NAFLD), Non-Alcoholic Steatohepatitis (NASH), Alcoholic Liver Disease (ALD), Cirrhosis, and Hepatocelullar Carcinoma (HCC) and its impact on the microbiota. Our results indicate that Bifidobacterium is a safe and effective probiotic for treating liver lesions. It successfully restored balance to the intestinal microbiota and improved biochemical and clinical parameters in NAFLD, ALD, and Cirrhosis. No significant adverse effects were identified. While more research is needed to establish its efficacy in treating NASH and HCC, the evidence suggests that Bifidobacterium is a promising probiotic for managing liver lesions.

Ethanol-induced changes to the gut microbiome compromise the intestinal homeostasis: a review

The intestine is the largest organ in terms of surface area in the human body. It is responsible not only for absorbing nutrients but also for protection against the external world. The gut microbiota is essential in maintaining a properly functioning intestinal barrier, primarily through producing its metabolites: short-chain fatty acids, bile acids, and tryptophan derivatives. Ethanol overconsumption poses a significant threat to intestinal health. Not only does it damage the intestinal epithelium, but, maybe foremostly, it changes the gut microbiome. Those ethanol-driven changes shift its metabolome, depriving the host of the protective effect the physiological gut microbiota has. This literature review discusses the impact of ethanol consumption on the gut, the gut microbiota, and its metabolome, providing a comprehensive overview of the mechanisms through which ethanol disrupts intestinal homeostasis and discussing potential avenues for new therapeutic intervention.

The Role of Bifidobacterium in Liver Diseases: A Systematic Review of Next-Generation Sequencing Studies

The physiopathology of liver diseases is complex and can be caused by various factors. Bifidobacterium is a bacterial genus commonly found in the human gut microbiome and has been shown to influence the development of different stages of liver diseases significantly. This study investigated the relationship between the Bifidobacterium genus and liver injury. In this work, we performed a systematic review in major databases using the key terms "Bifidobacterium", "ALD", "NAFLD", "NASH", "cirrhosis", and "HCC" to achieve our purpose. In total, 31 articles were selected for analysis. In particular, we focused on studies that used next-generation sequencing (NGS) technologies. The studies focused on assessing Bifidobacterium levels in the diseases and interventional aimed at examining the therapeutic potential of Bifidobacterium in the mentioned conditions. Overall, the abundance of Bifidobacterium was reduced in hepatic pathologies. Low levels of Bifidobacterium were associated with harmful biochemical and physiological parameters, as well as an adverse clinical outcome. However, interventional studies using different drugs and treatments were able to increase the abundance of the genus and improve clinical outcomes. These results strongly support the hypothesis that changes in the abundance of Bifidobacterium significantly influence both the pathophysiology of hepatic diseases and the related clinical outcomes. In addition, our critical assessment of the NGS methods and related statistical analyses employed in each study highlights concerns with the methods used to define the differential abundance of Bifidobacterium, including potential biases and the omission of relevant information.

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.

Sodium alginate combined with oxymatrine ameliorates CCl4-induced chemical hepatic fibrosis in mice

Hepatic fibrosis (HF) is a challenging clinical problem. Both sodium alginate (SA) and oxymatrine (OM) can be used to treat HF; however, the influence of viscosity on the therapeutic efficacy of sodium alginate is currently unknown. This study used a CCl4-induced HF mouse model to screen the specifications and doses of SA and investigate its therapeutic effects on HF in combination with OM. Sodium alginate of different viscosities ameliorated HF in mice, with 232 mPa·s SA delivered at a dose of 100 mg/kg showing remarkable therapeutic effect, characterized by reduced aspartate transaminase/alanine transaminase levels, reduced expression of α-SMA, collagen I, and other related genes, and increased abundance of beneficial intestinal probiotics such as Lactococcus and Blautia. The combination treatment further improved other related indices and increased the abundance of Phascolarctobacterium and Oscillospiraceae. These results suggest that the oral administration of SA may improve HF via the "gut-liver axis" based on the gut microbiota and has potential clinical applications.

Multi-Omics Analysis Demonstrates the Critical Role of Non-Ethanolic Components of Alcoholic Beverages in the Host Microbiome and Metabolome: A Human- and Animal-Based Study

It is known that alcoholic beverages alter the human gut microbiome. This study focused on the potential impact of non-ethanolic ingredients in whisky on the gut bacteriome. A pilot study was carried out on 15 whisky drinkers, 5 rice beer drinkers, and 9 non-drinkers to determine the effect of alcoholic beverages on the host microbiome and metabolome. Additionally, a mouse model was used to assess the differential impact of three whisky brands (each with an equal ethanol concentration). The results indicate that the non-ethanolic components have an impact on the gut microbiome, as well as on the metabolites in blood and feces. The amount of Prevotella copri, a typical core Indian gut bacterium, decreased in both the human and mouse groups of whisky type 1, but an increase in abundance of Helicobacteriaceae (p = 0.01) was noticed in both groups. Additionally, the alcohol-treated cohorts had lower levels of short-chain fatty acids (SCFAs), specifically butyric acid, and higher amounts of lipids and stress marker IL1-ß than the untreated groups (p = 0.04-0.01). Furthermore, two compounds, ethanal/acetaldehyde (found in all the whisky samples) and arabitol (unique to whisky type 1), were tested in the mice. Similar to the human subjects, the whisky type 1 treated mouse cohort and the arabitol-treated group showed decreased levels of Prevotella copri (p = 0.01) in their gut. The results showed that non-ethanolic compounds have a significant impact on host gut bacterial diversity and metabolite composition, which has a further vital impact on host health. Our work further emphasizes the need to study the impact of non-ethanolic ingredients of alcoholic beverages on host health.