Beneficial Shifts in Gut Microbiota by Lacticaseibacillus rhamnosus R0011 and Lactobacillus helveticus R0052 in Alcoholic Hepatitis

Clinical efficacy of probiotics in the treatment of alcoholic liver disease: a systematic review and meta-analysis

Objective

Alcoholic liver disease (ALD) is a liver damage disease caused by long-term heavy drinking. Currently, there is no targeted pharmaceutical intervention available for the treatment of this disease. To address this, this paper evaluates the efficacy and safety of probiotic preparation in treating ALD through conducting a meta-analysis, and provides a valuable insight for clinical decision-making.

Methods

A systematic search was conducted across databases, including PubMed, Embase, Web of Science, Cochrane Library, CNKI, VIP, Wanfang, and CBM from the inception dates to October 15, 2023, to identify clinical randomized controlled trials on probiotic preparations in the treatment of ALD. After the literature underwent screening, data extraction, and quality assessment, RevMan 5.3 and Stata 14.2 were employed for data analysis and processing.

Results

A total of 9 randomized controlled trials fulfilled the inclusion criteria. The results of the meta-analysis showed that probiotic preparation could significantly improve the liver function of patients with alcoholic liver disease compared with the control group. Probiotic intervention led to a significant reduction in the levels of alanine aminotransferase (MD=-13.36,95%CI:-15.80,-10.91;P<0.00001),aspartate aminotransferase (MD=-16.99,95%CI:-20.38,-13.59;P<0.00001),γ-glutamyl transpeptidase (MD=-18.79,95% CI:-28.23,-9.34; P<0.0001). Concurrently, the level of serum albumin (MD=0.19,95% CI:0.02,0.36;P=0.03) was increased. Furthermore, probiotic intervention could also modulate the composition of intestinal flora in patients with alcoholic liver disease, leading to an augmentation in Bifidobacteria and a reduction in Escherichia coli. However, in patients with alcoholic liver disease, probiotic intervention showed no significant effects on total bilirubin (MD=-0.01,95% CI:-0.17,0.15;P=0.91), tumor necrosis factor-α (MD=0.03,95% CI:-0.86,0.92;P=0.94) and interleukin-6 (MD=-5.3,95% CI:-16.04,5.45;P=0.33).

Conclusion

The meta-analysis indicates that probiotics can improve liver function in alcoholic liver disease, reduce inflammatory responses, regulate intestinal flora, which have potential value in the treatment of alcoholic liver disease.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42023472527.

ACG Clinical Guideline: Alcohol-Associated Liver Disease

ABSTRACT

Alcohol-associated liver disease (ALD) is the most common cause of advanced hepatic disease and frequent indication for liver transplantation worldwide. With harmful alcohol use as the primary risk factor, increasing alcohol use over the past decade has resulted in rapid growth of the ALD-related healthcare burden. The spectrum of ALD ranges from early asymptomatic liver injury to advanced disease with decompensation and portal hypertension. Compared with those with other etiologies of liver disease, patients with ALD progress faster and more often present at an advanced stage. A unique phenotype of advanced disease is alcohol-associated hepatitis (AH) presenting with rapid onset or worsening of jaundice, and acute on chronic liver failure in severe forms conveying a 1-month mortality risk of 20%-50%. The model for end stage disease score is the most accurate score to stratify AH severity (>20 defined as severe disease). Corticosteroids are currently the only available therapeutic with proven efficacy for patients with severe AH, providing survival benefit at 1 month in 50%-60% of patients. Abstinence of alcohol use, a crucial determinant of long-term outcomes, is challenging to achieve in ALD patients with concurrent alcohol use disorder (AUD). As patients with ALD are rarely treated for AUD, strategies are needed to overcome barriers to AUD treatment in patients with ALD and to promote a multidisciplinary integrated care model with hepatology, addiction medicine providers, and social workers to comprehensively manage the dual pathologies of liver disease and of AUD. Liver transplantation, a definitive treatment option in patients with advanced cirrhosis, should be considered in selected patients with AH, who are unresponsive to medical therapy and have a low risk of relapse to posttransplant alcohol use. Level of evidence and strength of recommendations were evaluated using the Grading of Recommendations, Assessment, Development, and Evaluations system. This guideline was developed under the American College of Gastroenterology Practice Parameters Committee.

Gut Microbiota and Bacterial Translocation in the Pathogenesis of Liver Fibrosis

Cirrhosis is the end result of liver fibrosis in chronic liver diseases. Studying the mechanisms of its development and developing measures to slow down and regress it based on this knowledge seem to be important tasks for medicine. Currently, disorders of the gut-liver axis have great importance in the pathogenesis of cirrhosis. However, gut dysbiosis, which manifests as increased proportions in the gut microbiota of Bacilli and Proteobacteria that are capable of bacterial translocation and a decreased proportion of Clostridia that strengthen the intestinal barrier, occurs even at the pre-cirrhotic stage of chronic liver disease. This leads to the development of bacterial translocation, a process by which those microbes enter the blood of the portal vein and then the liver tissue, where they activate Kupffer cells through Toll-like receptor 4. In response, the Kupffer cells produce profibrogenic cytokines, which activate hepatic stellate cells, stimulating their transformation into myofibroblasts that produce collagen and other elements of the extracellular matrix. Blocking bacterial translocation with antibiotics, probiotics, synbiotics, and other methods could slow down the progression of liver fibrosis. This was shown in a number of animal models but requires further verification in long-term randomized controlled trials with humans.

Intestinal Microbiotas and Alcoholic Hepatitis: Pathogenesis and Therapeutic Value

Alcoholic hepatitis (AH) is a rapidly progressing and severe stage of alcoholic liver disease, presenting a grim prognosis. Extensive research has elucidated several underlying mechanisms that contribute to the development of AH, including metabolic alterations, immune stimulation, and intestinal dysbiosis. These pathological changes intricately intertwine during the progression of AH. Notably, recent studies have increasingly highlighted the pivotal role of alterations in the intestinal microbiota in the pathogenesis of AH. Consequently, future investigations should place significant emphasis on exploring the dynamics of intestinal microbiota. In this comprehensive review, we consolidate the primary causes of AH while underscoring the influence of gut microbes. Furthermore, by examining AH treatment strategies, we delineate the potential therapeutic value of interventions targeting the gut microbiota. Given the existing limitations in AH treatment options, we anticipate that this review will contribute to forthcoming research endeavors aimed at advancing AH treatment modalities.

Roles of Gut Microbiota in Alcoholic Liver Disease

Alcoholic liver disease (ALD)-one of the most common liver diseases - involves a wide range of disorders, including asymptomatic hepatic steatosis, alcoholic hepatitis (AH), liver fibrosis, and cirrhosis. Alcohol consumption induces a weakened gut barrier and changes in the composition of the gut microbiota. The presence of CYP2E1 and its elevated levels in the gastrointestinal tract after alcohol exposure lead to elevated levels of ROS and acetaldehyde, inducing inflammation and oxidative damage in the gut. At the same time, the influx of harmful molecules such as the bacterial endotoxin LPS and peptidogly from gut dysbiosis can induce intestinal inflammation and oxidative damage, further compromising the intestinal mucosal barrier. In this process, various oxidative stress-mediated post-translational modifications (PTMs) play an important role in the integrity of the barrier, eg, the presence of acetaldehyde will result in the sustained phosphorylation of several paracellular proteins (occludin and zona occludens-1), which can lead to intestinal leakage. Eventually, persistent oxidative stress, LPS infiltration and hepatocyte damage through the enterohepatic circulation will lead to hepatic stellate cell activation and hepatic fibrosis. In addition, probiotics, prebiotics, synbiotics, fecal microbial transplantation (FMT), bioengineered bacteria, gut-restricted FXR agonists and others are promising therapeutic approaches that can alter gut microbiota composition to improve ALD. In the future, there will be new challenges to study the interactions between the genetics of individuals with ALD and their gut microbiome, to provide personalized interventions targeting the gut-liver axis, and to develop better techniques to measure microbial communities and metabolites in the body.