Treatment efficacy of a probiotic preparation for non-alcoholic steatohepatitis: A pilot trial

The effect of gut microbiome-targeted therapies in nonalcoholic fatty liver disease: a systematic review and network meta-analysis

Background

The incidence of NAFLD is increasing. Preclinical evidences indicate that modulation of the gut microbiome could be a promising target in nonalcoholic fatty liver disease.

Method

A systematic review and network meta-analysis was conducted to compare the effect of probiotics, synbiotics, prebiotics, fecal microbiota transplant, and antibiotics on the liver-enzyme, metabolic effects and liver-specific in patients with NAFLD. The randomized controlled trails (RCTs), limited to English language were searched from database such as Pubmed, Embase, Web of science and Cochrane Library from inception to November 2024. Review Manager 5.3 was used to to draw a Cochrane bias risk. Inconsistency test and publication-bias were assessed by Stata 14.0. Random effect model was used to assemble direct and indirect evidences. The effects of the intervention were presented as mean differences with 95% confidence interval.

Results

A total of 1921 patients from 37 RCTs were eventually included in our study. 23 RCTs evaluated probiotics, 10 RCTs evaluated synbiotics, 4 RCTs evaluated prebiotics, 3 RCTs evaluated FMT and one RCT evaluated antibiotics. Probiotics and synbiotics were associated with a significantly reduction in alanine aminotransferase [ALT, (MD: -5.09; 95%CI: -9.79, -0.39), (MD: -7.38, 95CI%: -11.94, -2.82)] and liver stiffness measurement by elastograph [LSM, (MD: -0.37;95%CI: -0.49, -0.25), (MD: -1.00;95%CI: -1.59, -0.41)]. In addition to, synbiotics was superior to probiotics in reducing LSM. Synbiotics was associated with a significant reduction of Controlled Attenuation Parameter [CAP, (MD: -39.34; 95%CI: -74.73, -3.95)]. Both probiotics and synbiotics were associated with a significant reduction of aspartate transaminase [AST, (MD: -7.81; 95%CI: -15.49, -0.12), (MD: -13.32; 95%CI: -23, -3.64)]. Probiotics and Allogenic FMT was associated with a significant reduction of Homeostatic Model Assessment for Insulin Resistance [HOMA-IR, (MD: -0.7, 95%CI: -1.26, -0.15), (MD: -1.8, 95%CI: -3.53, - 0.07)]. Probiotics was associated with a significant reduction of body mass index [BMI, MD: -1.84, 95%CI: -3.35, -0.33].

Conclusion

The supplement of synbiotics and probiotics maybe a promising way to improve liver-enzyme, LSM, and steatosis in patients with NAFLD. More randomized controlled trials are needed to determine the efficacy of FMT and antibiotics on NAFLD. And the incidence of adverse events of MTTs should be further explored.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, CRD42023450093.

Effects of Probiotics on Liver Diseases: Current In Vitro and In Vivo Studies

Various types of liver or hepatic diseases cause the death of about 2 million people worldwide every year, of which 1 million die from the complications of cirrhosis and another million from hepatocellular carcinoma and viral hepatitis. Currently, the second most common solid organ transplant is the liver, and the current rate represents less than 10% of global transplant requests. Hence, finding new approaches to treat and prevent liver diseases is essential. In liver diseases, the interaction between the liver, gut, and immune system is crucial, and probiotics positively affect the human microbiota. Probiotics are a non-toxic and biosafe alternative to synthetic chemical compounds. Health promotion by lowering cholesterol levels, stimulating host immunity, the natural gut microbiota, and other functions are some of the activities of probiotics, and their metabolites, including bacteriocins, can exert antimicrobial effects against a broad range of pathogenic bacteria. The present review discusses the available data on the results of preclinical and clinical studies on the effects of probiotic administration on different types of liver diseases.

Role of the Gut Microbiome in Metabolic Dysfunction-Associated Steatotic Liver Disease

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD)-previously described as nonalcoholic fatty liver disease-continues to rise globally. Despite this, therapeutic measures for MASLD remain limited. Recently, there has been a growing interest in the gut microbiome's role in the pathogenesis of MASLD. Understanding this relationship may allow for the administration of therapeutics that target the gut microbiome and/or its metabolic function to alleviate MASLD development or progression. This review will discuss the interplay between the gut microbiome's structure and function in relation to the development of MASLD, assess the diagnostic yield of gut microbiome-based signatures as a noninvasive tool to identify MASLD severity, and examine current and emerging therapies targeting the gut microbiome-liver axis.

The Role of Gut Microbiota Modification in Nonalcoholic Fatty Liver Disease Treatment Strategies

One of the most common chronic liver diseases is nonalcoholic fatty liver disease (NAFLD), which affects many people around the world. Gut microbiota (GM) dysbiosis seems to be an influential factor in the pathophysiology of NAFLD because changes in GM lead to fundamental changes in host metabolism. Therefore, the study of the effect of dysbiosis on the pathogenicity of NAFLD is important. European clinical guidelines state that the best advice for people with NAFLD is to lose weight and improve their lifestyle, but only 40% of people can achieve this goal. Accordingly, it is necessary to provide new treatment approaches for prevention and treatment. In addition to dietary interventions and lifestyle modifications, GM modification-based therapies are of interest. These therapies include probiotics, synbiotics, fecal microbiota transplantation (FMT), and next-generation probiotics. All of these treatments have had promising results in animal studies, and it can be imagined that acceptable results will be obtained in human studies as well. However, further investigations are required to generalize the outcomes of animal studies to humans.

The effect of synbiotics on liver enzymes, obesity indices, blood pressure, lipid profile, and inflammation in patients with non-alcoholic fatty liver: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Patients with non-alcoholic fatty liver disease (NAFLD) benefit from using synbiotics. However, findings from existing trials remain contentious. Therefore, this meta-analysis evaluated the effects of synbiotics on liver enzymes, blood pressure, inflammation, and lipid profiles in patients with NAFLD.

METHODS

We searched PubMed, Embase, Cochrane, Scopus, and Web of Science for randomized controlled trials (RCTs) regarding synbiotics supplementation in patients with NAFLD.

RESULTS

The meta-analysis revealed that synbiotics supplementation significantly improved liver enzymes (AST, WMD: -9.12 IU/L; 95 % CI: -13.19 to -5.05; ALT, WMD: -8.53 IU/L; 95 % CI: -15.07 to -1.99; GGT, WMD: -10.42 IU/L; 95 % CI: -15.19 to -5.65), lipid profile (TC, WMD: -7.74 mg/dL; 95 % CI: -12.56 to -2.92), obesity indices (body weight, WMD: -1.95 kg; 95 % CI: -3.69 to -0.22; WC, WMD: -1.40 cm; 95 % CI: -2.71 to -0.10), systolic blood pressure (SBP, WMD: -6.00 mmHg; 95 % CI: -11.52 to -0.49), and inflammatory markers (CRP, WMD: -0.69 mg/L; 95 % CI: -1.17 to -0.21; TNF-α, WMD: -14.01 pg/mL; 95 % CI: -21.81 to -6.20).

CONCLUSION

Overall, supplementation with synbiotics positively improved liver enzymes, obesity indices, and inflammatory cytokines in patients with NAFLD.

Meta-analysis of randomized controlled trials of the effects of synbiotics, probiotics, or prebiotics in controlling glucose homeostasis in non-alcoholic fatty liver disease patients

Background: Probiotics, prebiotics, and synbiotics have been suggested as a possible therapy for non-alcoholic fatty liver disease (NAFLD). However, their efficacy in improving blood glucose levels in NAFLD patients remains uncertain. Objective: The aim of this study was to assess the effects of supplementation with probiotics, prebiotics, or synbiotics on fasting blood glucose (FBG) levels in NAFLD patients. Methods: We searched PubMed, Web of Science, and Google Scholar for relevant trials published up to March 2024. Out of 3369 identified studies, 24 randomized controlled trials (RCTs) were included. Results: Probiotic, prebiotic, or synbiotic supplementation substantially reduced FBG (n = 23; standard mean difference (SMD) = -0.17; 95% confidence interval (CI): -0.30, -0.03; P = 0.02), fasting insulin levels (n = 12; SMD = -0.28; 95% CI: -0.49, -0.07; P = 0.01), and homeostatic model assessment for insulin resistance (HOMA-IR; n = 14; SMD = -0.28; 95% CI: -0.47, -0.09; P = 0.004). However, glycosylated hemoglobin (HbA1c; n = 3; SMD = -0.17; 95% CI: -0.48, 0.13; P = 0.27) was not significantly affected. The FBG-decreasing effect diminished as the body mass index (BMI) of volunteers increased in the baseline. Additionally, the number of probiotic strains and geographic region were shown to significantly affect FBG levels. Conclusion: This meta-analysis indicates that supplementation with probiotics, prebiotics, or synbiotics may aid in controlling glucose homeostasis in patients with NAFLD.

The effect of probiotic consumption on lipid profile, glycemic index, inflammatory markers, and liver function in NAFLD patients: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND-AIM

Non-alcoholic fatty liver disease (NAFLD1) is the most frequent chronic liver disorder worldwide. Currently, no pharmacological treatment has been approved for NAFLD. Probiotics have been suggested as a potential therapy for NAFLD. The aim of this systematic review and meta-analysis was to assess the impact of probiotic intake on liver tests, lipids, glycemic parameters and inflammatory markers in NAFLD patients.

METHODS

We searched electronic databases using related terms. Meta-analysis was performed using random-effects models. Clinical outcomes were presented as standard mean difference (SMD2) with a 95 % confidence interval (CI3). Publication bias and heterogeneity were evaluated in eligible studies.

RESULTS

Fifteen randomized clinical trials comprising 899 participants were included in our meta-analysis. Probiotic supplementation improved alanine transaminase [SMD -0.796; 95 % CI (-1.419, -0.172); p = 0.012], Homeostatic Model Assessment for Insulin Resistance (HOMA-IR4) [SMD -0.596; 95 % CI (-1.071, -0.121); p = 0.01] and insulin levels [SMD -1.10; 95 % CI (-2.121, -0.087); p = 0.03]. No significant effects were observed on fasting glucose, hemoglobin A1c, aspartate transaminase, lipid profile, interleukin-6 and tumor necrosis factor-α.

CONCLUSIONS

Probiotic intake may improve insulin sensitivity and alanine transaminase in NAFLD patients.

Natural Products as Hepatoprotective Agents-A Comprehensive Review of Clinical Trials

The hepatoprotective effects of natural products have been a significant focus in recent decades due to the growing demand for the help in the treatment of hepatic impairments. This review specifically delves into the findings of clinical trials involving 13 selected natural products, namely plants and their derived compounds (e.g., artichoke, berberine, and turmeric), algae (e.g., spirulina), probiotics, and other products like phospholipids and vitamin D. A literature search was performed in the Scopus database, PubMed, and Google Scholar, covering all articles found up to June 2024. Artichoke, berberine, chlorella, chicory, green tea, probiotics, phospholipids, schisandra, silymarin, spirulina, and vitamin D caused a decrease in liver enzymes, while for cinnamon and turmeric such an effect was either not observed or not convincing. The presented results indicate that some natural products might satisfactorily improve hepatic outcomes in NAFLD, NASH, and other liver disorders; however, further studies and metanalyses are needed to clearly demonstrate their effectiveness.

Optimal probiotic combinations for treating nonalcoholic fatty liver disease: A systematic review and network meta-analysis

BACKGROUND

Probiotic administration is a promising therapy for improving conditions in NAFLD patients. This network meta-analysis aimed to compare and estimate the relative effects of probiotic interventions and identify the optimal probiotic species for the treatment of NAFLD (Nonalcoholic fatty liver disease) patients.

METHODS

The PubMed, Web of Science, Embase, and Cochrane databases were searched from inception to 29 January 2024 to identify RCTs that were published in English. The GRADE framework was used to assess the quality of evidence contributing to each network estimate.

RESULTS

A total of 35 RCTs involving 2212 NAFLD patients were included in the analysis. For primary outcomes, Lactobacillus + Bifidobacterium + Streptococcus exhibited the highest probability of being the finest probiotic combination in terms of enhancing acceptability as well as reducing AST (SMD: -1.95 95% CI: -2.90, -0.99), ALT (SMD = -1.67, 95% CI: -2.48, -0.85), and GGT levels (SMD = -2.17, 95% CI: -3.27, -1.06). In terms of the secondary outcomes, Lactobacillus + Bifidobacterium + Streptococcus was also the best probiotic combination for reducing BMI (SMD = -0.45, 95% CI: -0.86, -0.04), LDL levels (SMD = -0.45, 95% CI: -0.87, -0.02), TC levels (SMD = -1.09, 95% CI: -1.89, -0.29), and TNF-α levels (SMD = -1.73, 95% CI: -2.72, -0.74).

CONCLUSION

This network meta-analysis revealed that Lactobacillus + Bifidobacterium + Streptococcus may be the most effective probiotic combination for the treatment of liver enzymes, lipid profiles, and inflammation factors. These findings can be used to guide the development of a probiotics-based treatment guideline for NAFLD since there are few direct comparisons between different therapies.

The effects of probiotics supplements on metabolic indices and clinical signs in patients with diabetic retinopathy, a randomized double blind clinical trial

Purpose

This study was carried out to evaluate the effects of probiotics administration on clinical status and metabolic profiles in diabetic retinopathy (DR) patients.

Methods

This randomized, double-blind, placebo-controlled trial was conducted among 72 DR patients. Subjects received probiotics including Lactobacillus acidophilus, Bifidobacterium bifidum, Bifidobacterium langum, Bifidobacterium lactis daily (2 × 109 CFU/each strain) (n = 36) or placebo (starch) (n = 36) and were instructed to take one capsule daily for 12 weeks. Finally, 55 participants [probiotic group (n = 30) and placebo group (n = 25)] completed the study. Fasting blood samples were obtained at baseline and after the 12-week intervention to determine metabolic profiles. To determine the effects of probiotic supplementation on clinical symptoms and biochemical variables, we used one-way repeated measures analysis of variance.

Results

After the 12-week intervention, compared with the placebo, probiotic supplementation significantly decreased means serum insulin concentrations (Probiotic group: -4.9 ± 6.5vs. Placebo group: 3.0 ± 7.7 µIU/mL, Ptime×group<0.001), homeostatic model assessment for insulin resistance (Probiotic group: -2.5 ± 3.8 vs. Placebo group: 1.1 ± 2.7, Ptime×group<0.001) and hemoglobin A1c (HbA1C) (Probiotic group: -0.4 ± 0.7 vs. Placebo group: -0.02 ± 0.2%, Ptime×group=0.01), and significantly increased the quantitative insulin sensitivity check index (QUICKI) (Probiotic group: 0.02 ± 0.03 vs. Placebo group: -0.03 ± 0.04, Ptime×group<0.001). There was no significant effect of probiotic administration on other metabolic profiles and clinical symptoms.

Conclusions

Overall, probiotic supplementation after 12 weeks in DR patients had beneficial effects on few metabolic profiles. This study was registered under the Iranian website for clinical trials as http://www.irct.ir: IRCT20130211012438N29.

Probiotics-A Promising Novel Therapeutic Approach in the Management of Chronic Liver Diseases

An increased incidence of liver diseases has been observed in recent years and is associated with gut dysbiosis, which causes bacterial infection, intestinal permeability, and further leads to disease-related complications. Probiotics, active microbial strains, are gaining more clinical importance due to their beneficial effect in the management of many diseases, including liver diseases. Clinical scenarios show strong evidence that probiotics have efficacy in treating liver diseases due to their ability to improve epithelial barrier function, prevent bacterial translocation, and boost the immune system. Moreover, probiotics survive both bile and gastric acid to reach the gut and exert their health benefit. Evidence shows that probiotics are a promising approach to prevent several complications in clinical practice. Herein, we discuss the recent evidence, challenges, and appropriate use of probiotics in managing advanced liver diseases, which may have an impact on future therapeutic strategies. Furthermore, the superior effect of strain-specific probiotics and their efficacy and safety in managing liver diseases are discussed.

Can modulation of gut microbiota affect anthropometric indices in patients with non-alcoholic fatty liver disease? An umbrella meta-analysis of randomized controlled trials

Background and aim

Modulating the gut microbiota population by administration of probiotics, prebiotics, and synbiotics has shown to have a variety of health benefits in different populations, particularly those with metabolic disorders. Although the promising effects of these compounds have been observed in the management of patients with non-alcoholic fatty liver disease (NAFLD), the exact effects and the mechanisms of action are yet to be understood. In the present study, we aimed to evaluate how gut microbiota modulation affects anthropometric indices of NAFLD patients to achieve a comprehensive summary of current evidence-based knowledge.

Methods

Two researchers independently searched international databases, including PubMed, Scopus, and Web of Science, from inception to June 2023. Meta-analysis studies that evaluated the effects of probiotics, prebiotics, and synbiotics on patients with NAFLD were entered into our umbrella review. The data regarding anthropometric indices, including body mass index, weight, waist circumference (WC), and waist-to-hip ratio (WHR), were extracted by the investigators. The authors used random effect model for conducting the meta-analysis. Subgroup analysis and sensitivity analysis were also performed.

Results

A total number of 13 studies were finally included in our study. Based on the final results, BMI was significantly decreased in NAFLD patients by modulation of gut microbiota [effect size (ES): -0.18, 05% CI: -0.25, -0.11, P<0.001]; however, no significant alteration was observed in weight and WC (ES: -1.72, 05% CI: -3.48, 0.03, P=0.055, and ES: -0.24, 05% CI: -0.75, 0.26, P=0.353, respectively). The results of subgroup analysis showed probiotics had the most substantial effect on decreasing BMI (ES: -0.77, 95% CI: -1.16, -0.38, P<0.001) followed by prebiotics (ES: -0.51, 95% CI: -0.76, -0.27, P<0.001) and synbiotics (ES: -0.12, 95% CI: -0.20, -0.04, P=0.001).

Conclusion

In conclusion, the present umbrella meta-analysis showed that although modulation of gut microbiota by administration of probiotics, prebiotics, and synbiotics had promising effects on BMI, no significant change was observed in the WC and weight of the patients. No sufficient data were available for other anthropometric indices including waist-to-hip ratio and waist-to-height ratio and future meta-analyses should be done in this regard.

Gut microbiota in MAFLD: therapeutic and diagnostic implications

Metabolic dysfunction-associated fatty liver disease (MAFLD), formerly known as nonalcoholic fatty liver disease, is becoming a significant contributor to chronic liver disease globally, surpassing other etiologies, such as viral hepatitis. Prevention and early treatment strategies to curb its growing prevalence are urgently required. Recent evidence suggests that targeting the gut microbiota may help treat and alleviate disease progression in patients with MAFLD. This review aims to explore the complex relationship between MAFLD and the gut microbiota in relation to disease pathogenesis. Additionally, it delves into the therapeutic strategies targeting the gut microbiota, such as diet, exercise, antibiotics, probiotics, synbiotics, glucagon-like peptide-1 receptor agonists, and fecal microbiota transplantation, and discusses novel biomarkers, such as microbiota-derived testing and liquid biopsy, for their diagnostic and staging potential. Overall, the review emphasizes the urgent need for preventive and therapeutic strategies to address the devastating consequences of MAFLD at both individual and societal levels and recognizes that further exploration of the gut microbiota may open avenues for managing MAFLD effectively in the future.

Improvement of NASH and liver fibrosis through modulation of the gut-liver axis by a novel intestinal FXR agonist

Farnesoid X receptor (FXR) plays a pivotal role in the regulation of bile acid homeostasis and is involved in the pathogenesis of nonalcoholic steatohepatitis (NASH). Although FXR agonists effectively alleviate pathological features of NASH, adverse effects such as disturbance of cholesterol homeostasis and occurrence of pruritus remain to be addressed. Here, we identified a novel FXR agonist, ID119031166 (ID166), and explored the pharmacological benefits of ID166 in the treatment of NASH. ID166, a potent and selective non-bile acid FXR agonist, exhibits preferential distribution in the intestine and shows no agonist activity against potential itch receptors including Mas-related G protein-coupled receptor X4 (MRGPRX4). Interestingly, ID166 significantly attenuated total nonalcoholic fatty liver disease (NAFLD) activity and liver fibrosis in a free choice diet-induced NASH hamster model. In addition, ID166 drastically modulated the relative abundance of five gut microbes and reduced the increase in plasma total bile acid levels to normal levels in NASH hamsters. Moreover, long-term treatment with ID166 significantly improved key histological features of NASH and liver fibrosis in a diet-induced NASH mouse model. In the NASH mouse livers, RNA-seq analysis revealed that ID166 reduced the gene expression changes associated with both NASH and liver fibrosis. Notably, ID166 exhibited no substantial effects on scratching behavior and serum IL-31 levels in mice. Our findings suggest that ID166, a novel FXR agonist with improved pharmacological properties, provides a preclinical basis to optimize clinical benefits for NASH drug development.

The Many Faces of Metabolic Dysfunction-Associated Fatty Liver Disease Treatment: From the Mediterranean Diet to Fecal Microbiota Transplantation

The gastrointestinal tract is inhabited by the gut microbiota. The main phyla are Firmicutes and Bacteroidetes. In non-alcoholic fatty liver disease, now renamed metabolic dysfunction-associated fatty liver disease (MAFLD), an alteration in Firmicutes and Bacteroidetes abundance promotes its pathogenesis and evolution into non-alcoholic steatohepatitis, liver cirrhosis, and hepatocellular carcinoma. For this reason, early treatment is necessary to counteract its progression. The aim of the present narrative review is to evaluate the different therapeutic approaches to MAFLD. The most important treatment for MAFLD is lifestyle changes. In this regard, the Mediterranean diet could be considered the gold standard in the prevention and treatment of MAFLD. In contrast, a Western diet should be discouraged. Probiotics and fecal microbiota transplantation seem to be valid, safe, and effective alternatives for MAFLD treatment. However, more studies with a longer follow-up and with a larger cohort of patients are needed to underline the more effective approaches to contrasting MAFLD.

Protection against fibrosis by a bacterial consortium in metabolic dysfunction-associated steatohepatitis and the role of amino acid metabolism

The gut microbiota drives progression to liver fibrosis, the main determinant of mortality in metabolic dysfunction-associated steatohepatitis (MASH). In this study, we aimed to identify bacterial species associated with protection against liver fibrosis in a high-risk population, and test their potential to protect against liver fibrosis in vivo. Based on stool shotgun metagenomic sequencing of 340 subjects from a population cohort disproportionally affected by MASH, we identified bacterial species from the Bacteroidales and Clostridiales orders associated with reduced risk of liver fibrosis. A bacterial consortium was subsequently tested in a mouse model of MASH, which demonstrated protective effects against liver fibrosis. Six of the eight inoculated bacteria were detected in mouse stool and liver. Intrahepatic presence of bacteria was further confirmed by bacterial culture of mouse liver tissue. Changes in liver histological parameters, gut functional profiles, and amino acid profiles were additionally assessed. Comparison between fibrosis-associated human metagenome and bacteria-induced metagenome changes in mice identified microbial functions likely to mediate the protective effect against liver fibrosis. Amino acid profiling confirmed an increase in cysteine synthase activity, associated with reduced fibrosis. Other microbiota-induced changes in amino acids associated with reduced fibrosis included increased gut asparaginase activity and decreased hepatic tryptophan-to-kynurenine conversion. This human-to-mouse study identified bacterial species and their effects on amino acid metabolism as innovative strategies to protect against liver fibrosis in MASH.

The Gut Microbiome and Autoimmune Hepatitis: Implications for Early Diagnostic Biomarkers and Novel Therapies

Autoimmune hepatitis (AIH) is a serious chronic liver disease that may last for decades and eventually develop into cirrhosis and liver failure. In recent years, people have paid more attention to the microbiome-gut-liver axis, which provides guidance for all to explore the role of microbiome in the occurrence and development of liver diseases. In this review, the possible mechanism of intestinal microbes promoting the occurrence of AIH, mainly expounding the key ways such as bacterial ecological imbalance, intestinal leakage, and molecular simulation between microbes and autoantigens is summarized. In addition, this paper also discusses that intestinal microbiome has great potential as a biomarker for early diagnosis of AIH, and intestinal microbiome is also a candidate target for prevention and treatment of AIH. Finally, the study summarizes and prospects the targeted therapy of intestinal microorganisms to prevent the occurrence and development of AIH.

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.

The gut-liver axis and gut microbiota in health and liver disease

The trillions of microorganisms in the human intestine are important regulators of health, and disruptions in the gut microbial communities can cause disease. The gut, liver and immune system have a symbiotic relationship with these microorganisms. Environmental factors, such as high-fat diets and alcohol consumption, can disrupt and alter microbial communities. This dysbiosis can lead to dysfunction of the intestinal barrier, translocation of microbial components to the liver and development or progression of liver disease. Changes in metabolites produced by gut microorganisms can also contribute to liver disease. In this Review, we discuss the importance of the gut microbiota in maintenance of health and the alterations in microbial mediators that contribute to liver disease. We present strategies for modulation of the intestinal microbiota and/or their metabolites as potential treatments for liver disease.

Use of probiotics, prebiotics, and synbiotics in non-alcoholic fatty liver disease: A systematic review and meta-analysis

BACKGROUND AND AIM

Patients with non-alcoholic fatty liver disease (NAFLD) exhibit compositional changes in their gut microbiome, which represents a potential therapeutic target. Probiotics, prebiotics, and synbiotics are microbiome-targeted therapies that have been proposed as treatment for NAFLD. We aim to systematically review the effects of these therapies in liver-related outcomes of NAFLD patients.

METHODS

We conducted a systematic search in Embase (Ovid), Medline (Ovid), Scopus, Cochrane, and EBSCOhost from inception to August 19, 2022. We included randomized controlled trials (RCTs) that treated NAFLD patients with prebiotics and/or probiotics. We meta-analyzed the outcomes using standardized mean difference (SMD) and assessed study heterogeneity using Cochran's Q test and I2 statistics. Risk of bias was assessed using the Cochrane Risk-of-Bias 2 tool.

RESULTS

A total of 41 (18 probiotics, 17 synbiotics, and 6 prebiotics) RCTs were included. Pooled data demonstrated that the intervention had significantly improved liver steatosis (measured by ultrasound grading) (SMD: 4.87; 95% confidence interval [CI]: 3.27, 7.25), fibrosis (SMD: -0.61 kPa; 95% CI: -1.12, -0.09 kPa), and liver enzymes including alanine transaminase (SMD: -0.86 U/L; 95% CI: -1.16, -0.56 U/L), aspartate transaminase (SMD: -0.87 U/L; 95% CI: -1.22, -0.52 U/L), and gamma-glutamyl transferase (SMD: -0.77 U/L; 95% CI: -1.26, -0.29 U/L).

CONCLUSIONS

Microbiome-targeted therapies were associated with significant improvements in liver-related outcomes in NAFLD patients. Nevertheless, limitations in existing literature like heterogeneity in probiotic strains, dosage, and formulation undermine our findings. This study was registered with PROSPERO (CRD42022354562) and supported by the Nanyang Technological University Start-up Grant and Wang Lee Wah Memorial Fund.

The Crosstalk between Gut Microbiota and Bile Acids Promotes the Development of Non-Alcoholic Fatty Liver Disease

Recently the roles of gut microbiota are highly regarded in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). The intestinal bacteria regulate the metabolism of bile acids depending on bile salt hydrolase (BSH), 7-dehydroxylation, hydroxysteroid dehydrogenase (HSDH), or amide conjugation reaction, thus exerting effects on NAFLD development through bile acid receptors such as farnesoid X receptor (FXR), Takeda G-protein-coupled bile acid protein 5 (TGR5), and vitamin D receptor (VDR), which modulate nutrient metabolism and insulin sensitivity via interacting with downstream molecules. Reversely, the composition of gut microbiota is also affected by the level of bile acids in turn. We summarize the mutual regulation between the specific bacteria and bile acids in NAFLD and the latest clinical research based on microbiota and bile acids, which facilitate the development of novel treatment modalities in NAFLD.

Probiotic Supplementation, Hepatic Fibrosis, and the Microbiota Profile in Patients with Nonalcoholic Steatohepatitis: A Randomized Controlled Trial

BACKGROUND

Promising results in improvement of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis (NASH) have been identified following probiotic (PRO) treatment.

OBJECTIVES

To evaluate PRO supplementation on hepatic fibrosis, inflammatory and metabolic markers, and gut microbiota in NASH patients.

METHODS

In a double-blind, placebo-controlled clinical trial, 48 patients with NASH with a median age of 58 y and median BMI of 32.7 kg/m2 were randomly assigned to receive PROs (Lactobacillus acidophilus 1 × 109 colony forming units and Bifidobacterium lactis 1 × 109 colony forming units) or a placebo daily for 6 mo. Serum aminotransferases, total cholesterol and fractions, C-reactive protein, ferritin, interleukin-6, tumor necrosis factor-α, monocyte chemoattractant protein-1, and leptin were assessed. To evaluate liver fibrosis, Fibromax was used. In addition, 16S rRNA gene-based analysis was performed to evaluate gut microbiota composition. All assessments were performed at baseline and after 6 mo. For the assessment of outcomes after treatment, mixed generalized linear models were used to evaluate the main effects of the group-moment interaction. For multiple comparisons, Bonferroni correction was applied (α = 0.05/4 = 0.0125). Results for the outcomes are presented as mean and SE.

RESULTS

The AST to Platelet Ratio Index (APRI) score was the primary outcome that decreased over time in the PRO group. Aspartate aminotransferase presented a statistically significant result in the group-moment interaction analyses, but no statistical significance was found after the Bonferroni correction. Liver fibrosis, steatosis, and inflammatory activity presented no statistically significant differences between the groups. No major shifts in gut microbiota composition were identified between groups after PRO treatment.

CONCLUSIONS

Patients with NASH who received PRO supplementation for 6 mo presented improvement in the APRI score after treatment. These results draw attention to clinical practice and suggest that supplementation with PROs alone is not sufficient to improve enzymatic liver markers, inflammatory parameters, and gut microbiota in patients with NASH. This trial was registered at clinicaltrials.gov as NCT02764047.

Probiotics, prebiotics, and synbiotics in nonalcoholic fatty liver disease and alcohol-associated liver disease

The use of probiotics, prebiotics, and synbiotics has become an important therapy in numerous gastrointestinal diseases in recent years. Modifying the gut microbiota, this therapeutic approach helps to restore a healthy microbiome. Nonalcoholic fatty liver disease and alcohol-associated liver disease are among the leading causes of chronic liver disease worldwide. A disrupted intestinal barrier, microbial translocation, and an altered gut microbiome metabolism, or metabolome, are crucial in the pathogenesis of these chronic liver diseases. As pro-, pre-, and synbiotics modulate these targets, they were identified as possible new treatment options for liver disease. In this review, we highlight the current findings on clinical and mechanistic effects of this therapeutic approach in nonalcoholic fatty liver disease and alcohol-associated liver disease.

Effects of probiotics on non-alcoholic fatty liver disease: a review of human clinical trials

Non-alcoholic fatty liver disease (NAFLD) is a global public health issue, of which the prevalence is about 25% worldwide. The incidence of NAFLD is increasing in patients with obesity, type 2 diabetes (T2DM) and the metabolic syndrome. The crosstalk between gut microbiota and metabolism-related diseases has been raised great concern. Patients with NAPLD were observed with disruption of gut microbiota. Several researches showed that gut microbiota was the determination in the progression of NAFLD by the experiments using fecal microbiota transplants. The application of probiotics, as one of the most important strategies for the regulation of gut microbiota disorder, have been explored whether it is beneficial to gut-related diseases of intestine-distal organs. Some probiotics were showed to improve the liver parameters and phenotype in patients with NAFLD. The oral intake of them might become the effective management for the prevention and treatment of NAFLD. In this review, we summarized the human clinical trials focusing on the effects of probiotics on NAFLD to give some evidential reference for the administration of NAFLD.

The Role of Choline, Soy Isoflavones, and Probiotics as Adjuvant Treatments in the Prevention and Management of NAFLD in Postmenopausal Women

Nonalcoholic fatty liver disease (NAFLD) is a prevalent condition among postmenopausal women that can lead to severe liver dysfunction and increased mortality. In recent years, research has focused on identifying potential lifestyle dietary interventions that may prevent or treat NAFLD in this population. Due to the complex and multifactorial nature of NAFLD in postmenopausal women, the disease can present as different subtypes, with varying levels of clinical presentation and variable treatment responses. By recognizing the significant heterogeneity of NAFLD in postmenopausal women, it may be possible to identify specific subsets of individuals who may benefit from targeted nutritional interventions. The purpose of this review was to examine the current evidence supporting the role of three specific nutritional factors-choline, soy isoflavones, and probiotics-as potential nutritional adjuvants in the prevention and treatment of NAFLD in postmenopausal women. There is promising evidence supporting the potential benefits of these nutritional factors for NAFLD prevention and treatment, particularly in postmenopausal women, and further research is warranted to confirm their effectiveness in alleviating hepatic steatosis in this population.

Effects of various interventions on non-alcoholic fatty liver disease (NAFLD): A systematic review and network meta-analysis

Background: With the increasing prevalence of obesity and metabolic syndrome, the incidence of non-alcoholic fatty liver disease (NAFLD) is also increasing. In the next decade, NAFLD may become the main cause of liver transplantation. Therefore, the choice of treatment plan is particularly important. The purpose of this study was to compare several interventions in the treatment of NAFLD to provide some reference for clinicians in selecting treatment methods.

Methods: We searched Public Medicine (PubMed), Medline, Excerpta Medica Database (Embase), and Cochrane Library from January 2013 to January 2023 to identify randomized controlled trials (RCTs) published in English. The network meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Forty-three studies accounting for a total of 2,969 patients were included, and alanine aminotransferase (ALT), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL) were selected as outcome measures for analysis and comparison.

Results: We evaluated the results of drug, diet, and lifestyle interventions between the intervention and control groups. Curcumin (CUN) and probiotics (PTC) were selected for medication, the Mediterranean diet (MDED) was selected for special diet (SPD), and various kinds of exercise and lifestyle advice were selected for lifestyle interventions (LFT). The SUCRA was used to rank interventions according to the effect on ALT indicators (SUCRA: PTC 80.3%, SPD 65.2%, LFT 61.4%, PLB 32.8%, CUN 10.2%), TC indicators (SUCRA: PTC 89.4%, SPD 64%, CUN 34%, LFT 36.6%, PLB 17%), and LDL indicators (SUCRA: PTC 84.2%, CUN 69.5%, LFT 51.7%, PLB 30.1%, SPD 14.5%). The pairwise meta-analysis results showed that MDED was significantly better than NT in improving ALT [SMD 1.99, 95% CI (0.38, 3.60)]. In terms of improving TC and LDL, ATS was significantly better than NT [SMD 0.19, 95% CI (0.03, 0.36)] [SMD 0.18, 95% CI (0.01, 0.35)].

Conclusion: Our study showed that PTC is most likely to be the most effective treatment for improving NAFLD indicators. Professional advice on diet or exercise was more effective in treating NAFLD than no intervention.

Efficacy of probiotics on nonalcoholic fatty liver disease: A meta-analysis

OBJECTIVES

The intestinal flora is closely related to the pathogenesis of nonalcoholic fatty liver disease (NAFLD). This study intends to systematically evaluate the efficacy and safety of probiotics in the treatment of NAFLD through a meta-analysis of published randomized controlled trials.

METHODS

This study was conducted through a search of published randomized controlled trials using probiotic-related drugs for the treatment of nonalcoholic fatty liver disease (up to April 6, 2022). The JADAD evaluation table was used to evaluate the quality of the literatures included in the search, and the risk of bias was evaluated according to the Cochrane evaluation manual. Finally, RevMan5.4 software was used for meta-analysis.

RESULTS

A total of 21 randomized clinical trials involving 1037 patients with NAFLD were included in this study. Meta-analysis results showed that after probiotic intervention, liver function, blood lipid level, blood glucose levels and insulin levels were significantly reduced, which had a good effect on improving hepatic steatosis. However, it did not significantly improve BMI, inflammatory factors, or homeostasis model assessment of insulin resistance. Through the subgroup analysis of the course of treatment, it was found that ALT, GGT, TG, and blood sugar improved better in the probiotic treatment course of greater than or equal to 12 weeks.

CONCLUSION

This study shows that the use of probiotics therapy has a good regulating effect on liver function, steatosis, blood glucose level, insulin level and blood lipid level in NAFLD patients.

Fecal Microbiota Transplantation in NAFLD Treatment

Introduction: Gut microbiota is not only a taxonomic biologic ecosystem but is also involved in human intestinal and extra-intestinal functions such as immune system modulation, nutrient absorption and digestion, as well as metabolism regulation. The latter is strictly linked to non-alcoholic fatty liver disease (NAFLD) pathophysiology. Materials and methods: We reviewed the literature on the definition of gut microbiota, the concepts of “dysbiosis” and “eubiosis”, their role in NAFLD pathogenesis, and the data on fecal microbiota transplantation (FMT) in these patients. We consulted the main medical databases using the following keywords, acronyms, and their associations: gut microbiota, eubiosis, dysbiosis, bile acids, NAFLD, and FMT. Results: Gut microbiota qualitative and quantitative composition is different in healthy subjects vs. NALFD patients. This dysbiosis is associated with and involved in NAFLD pathogenesis and evolution to non-acoholic steatohepatitis (NASH), liver cirrhosis, and hepatocellular carcinoma (HCC). In detail, microbial-driven metabolism of bile acids (BAs) and interaction with hepatic and intestinal farnesoid nuclear X receptor (FXR) have shown a determinant role in liver fat deposition and the development of fibrosis. Over the use of pre- or probiotics, FMT has shown preclinical and initial clinical promising results in NAFLD treatment through re-modulation of microbial dysbiosis. Conclusions: Promising clinical data support a larger investigation of gut microbiota dysbiosis reversion through FMT in NAFLD using randomized clinical trials to design precision-medicine treatments for these patients at different disease stages.

Targeting the Gut Microbiome to Treat Metabolic Dysfunction-Associated Fatty Liver Disease: Ready for Prime Time?

Numerous studies show a modification of the gut microbiota in patients with obesity or diabetes. Animal studies have also shown a causal role of gut microbiota in liver metabolic disorders including steatosis whereas the human situation is less clear. Patients with metabolic dysfunction associated fatty liver disease (MAFLD) also have a modification in their gut microbiota composition but the changes are not fully characterized. The absence of consensus on a precise signature is probably due to disease heterogeneity, possible concomitant medications and different selection or evaluation criteria. The most consistent changes were increased relative abundance of Proteobacteria, Enterobacteriaceae and Escherichia species and decreased abundance of Coprococcus and Eubacterium. Possible mechanisms linking the microbiota and MAFLD are increased intestinal permeability with translocation of microbial products into the portal circulation, but also changes in the bile acids and production of microbial metabolites such as ethanol, short chain fatty acids and amino acid derivatives able to modulate liver metabolism and inflammation. Several interventional studies exist that attempt to modulate liver disease by administering antibiotics, probiotics, prebiotics, synbiotics, postbiotics or fecal transplantation. In conclusion, there are both gaps and hopes concerning the interest of gut microbiome evaluation for diagnosis purposes of MAFLD and for new therapeutic developments that are often tested on small size cohorts.

The Effects of Probiotics, Prebiotics and Synbiotics in Non-Alcoholic Fat Liver Disease (NAFLD) and Non-Alcoholic Steatohepatitis (NASH): A Systematic Review

Modifications in the microbiota caused by environmental and genetic reasons can unbalance the intestinal homeostasis, deregulating the host's metabolism and immune system, intensifying the risk factors for the development and aggravation of non-alcoholic fat liver disease (NAFLD). The use of probiotics, prebiotics and synbiotics have been considered a potential and promising strategy to regulate the gut microbiota and produce beneficial effects in patients with liver conditions. For this reason, this review aimed to evaluate the effectiveness of probiotics, prebiotics, and symbiotics in patients with NAFLD and NASH. Pubmed, Embase, and Cochrane databases were consulted, and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines were followed. The clinical trials used in this study demonstrated that gut microbiota interventions could improve a wide range of markers of inflammation, glycemia, insulin resistance, dyslipidemia, obesity, liver injury (decrease of hepatic enzymes and steatosis and fibrosis). Although microbiota modulators do not play a healing role, they can work as an important adjunct therapy in pathological processes involving NAFLD and its spectrums, either by improving the intestinal barrier or by preventing the formation of toxic metabolites for the liver or by acting on the immune system.

The promising role of probiotics/prebiotics/synbiotics in energy metabolism biomarkers in patients with NAFLD: A systematic review and meta-analysis

Background

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease with a high prevalence worldwide, seriously harming human health, and its pathogenesis remains unclear. In recent years, increasing evidence has indicated that intestinal microbiota plays an important role in the occurrence and development of NAFLD. The regulation method of probiotics/prebiotics/synbiotics can alter the intestinal microbiota and has been suggested as an option in the treatment of NAFLD.

Methods

Five databases of PubMed, Embase, the Cochrane Library, clinicaltrails.gov, and China National Knowledge Infrastructure were searched initially, and then the eligible studies were screened. Finally, the data of included studieswere extracted, combined and analyzed

Results

A total of 29 randomized controlled trials involving 2,110 patients were included in this study. The results showed that using probiotics/prebiotics/synbiotics in the intervention group could reduce the levels of glucose (SMD = −0.23, 95% CI [−0.45, −0.01], P = 0.04), HOMA-IR (SMD = −0.47, 95% CI [−0.63, −0.31], P < 0.00001) and insulin (SMD = −0.46, 95% CI [−0.76, −0.16], P = 0.002) in sugar metabolism; in terms of lipid metabolism, the levels of TC (SMD = −0.62, 95%CI [−0.87, −0.36], P < 0.00001), and LDL-C (SMD = −0.57, 95%CI [−0.85, −0.28], P < 0.00001) were decreased; and the level of ALB was decreased in protein metabolism (SMD = −0.34, 95%CI [−0.61, −0.06], P = 0.02).

Conclusions

Based on the current evidence, probiotics/prebiotics/synbiotics may improve energy metabolism biomarkers in the NAFLD population, but these effects still need to be confirmed by further research.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/#aboutpage.

The clinical effect of probiotics on patients with non-alcoholic fatty liver disease: a meta-analysis

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease. The present study explores the clinical efficacy of probiotics in the treatment of patients with NAFLD by conducting a systematic search of relevant databases. The RevMan 5.4 software was used to evaluate the effects of probiotics on liver function (i.e. alanine aminotransferase [ALT], aspartate aminotransferase [AST], gamma-glutamyl transferase [GGT], lipid metabolism, blood glucose, inflammatory factors [e.g. tumor necrosis factor-α, TNF-α] and body mass index [BMI]) in patients with NAFLD. A total of 18 high-quality studies were included in the final meta-analysis. The results of the meta-analysis showed that the use of probiotics in the adjuvant treatment of patients with NAFLD improved liver function and reduced ALT levels (mean difference [MD]: -0.07; 95% confidence interval [CI]: -12.95, -7.19), AST levels (MD: -11.90; 95% CI: -16.55, -7.25) and GGT levels (MD: -8.61; 95% CI: -14.74, -2.48); additionally, the treatment effect was more obvious when the treatment time exceeded 12 weeks. Probiotic therapy reduced patients' triglyceride levels (MD: -9.71; 95% CI: -18.39, -1.03) and total cholesterol levels (MD: -22.31; 95% CI: -25.41, -19.21). Probiotic treatment improved patients' levels of fasting blood (MD: -8.22; 95% CI: -12.25, -4.20), insulin (MD: -2.68; 95% CI: -4.94, -0.41) and insulin resistance (MD: -0.72; 95% CI: -1.21, -0.24). Probiotic adjuvant therapy for patients with NAFLD reduced their BMI by approximately 1.67 (95% CI: -2.93, -0.41) and TNF-α levels. The adjuvant treatment of NAFLD with probiotics has a positive clinical effect, which is influenced by treatment time.

Therapeutic mechanisms and beneficial effects of non-antidiabetic drugs in chronic liver diseases

The global burden of chronic liver disease (CLD) is substantial. Due to the limited indication of and accessibility to antiviral therapy in viral hepatitis and lack of effective pharmacological treatment in nonalcoholic fatty liver disease, the beneficial effects of antidiabetics and non-antidiabetics in clinical practice have been continuously investigated in patients with CLD. In this narrative review, we focused on non-antidiabetic drugs, including ursodeoxycholic acid, silymarin, dimethyl4,4'-dimethoxy-5,6,5',6'-dimethylenedixoybiphenyl-2,2'-dicarboxylate, L-ornithine L-aspartate, branched chain amino acids, statin, probiotics, vitamin E, and aspirin, and summarized their beneficial effects in CLD. Based on the antioxidant, anti-inflammatory properties, and regulatory functions in glucose or lipid metabolism, several non-antidiabetic drugs have shown beneficial effects in improving liver histology, aminotransferase level, and metabolic parameters and reducing risks of hepatocellular carcinoma and mortality, without significant safety concerns, in patients with CLD. Although the effect as the centerpiece management in patients with CLD is not robust, the use of these non-antidiabetic drugs might be potentially beneficial as an adjuvant or combined treatment strategy.

Effect of Probiotics Therapy on Nonalcoholic Fatty Liver Disease

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease in the world. The pathogenesis of NAFLD is complex and multifactorial. Clinical studies have shown that alterations in the gut microbiota play a key role in NAFLD. The purpose of this study was to analyze the effect of probiotic supplementation on the treatment of NAFLD patients based on various indicators.

METHODS

We conducted a meta-analysis investigating the relationship between NAFLD and probiotic supplementation. Embase, PubMed, and Web of Science databases were searched by computer, and then, eligible studies were identified. Finally, a total of high-quality randomized controlled trials were selected involving 1403 participants. Meta-analysis was performed using the RevMan 5.3 software which was systematically searched for works published through Dec. 1, 2021, in the present study.

RESULTS

The meta-analysis results showed that the probiotics supplementation improved hepatocyte injury and significantly reduced the level of ALT (P = 0.00001), AST (P = 0.0009), GGT (P = 0.04), TG (P = 0.01), LDL-C (P = 0.0005), HDL-C (P = 0.0002), insulin (P = 0.003), IR (P = 0.03), BMI (P = 0.03), TNF-α (P = 0.03), and CRP (P = 0.02), respectively, in NAFLD patients.

CONCLUSION

The present study suggests that probiotics therapy may improve liver enzyme levels, regulated lipid metabolism, reduced insulin resistance, and improved inflammation in NAFLD patients. It supports the potential role of probiotics supplementation in the treatment of NAFLD.

Effect of Probiotics on Liver Enzymes in Patients With Non-alcoholic Fatty Liver Disease: An Umbrella of Systematic Review and Meta-Analysis

Non-alcoholic fatty liver disease (NAFLD) has become prevalent in recent decades, especially in developed countries; yet the approaches for preventing and treating NAFLD are not clear. This study aimed to summarize meta-analyses of randomized controlled trials that examined the effects of probiotics on NAFLD. We systematically searched PubMed, Scopus, Embase, Web of Science, and Cochrane Central Library databases up to August 2021. All Meta-analysis studies assessing the effect of probiotics on liver function tests [alanine aminotransferase (ALT), aspartate aminotransferase (AST), and Gamma-glutamyl transferase (GGT)] were included. Meta-analysis was conducted using a random-effects model. Sensitivity and subgroup analyses were also performed. The umbrella study covered ten eligible studies involving 5,162 individuals. Beneficial effects of probiotics supplementation were revealed on ALT (ES = −10.54 IU/L; 95% CI: −12.70, −8.39; p < 0.001; I² = 60.9%, p = 0.006), AST (ES = −10.19 IU/L, 95%CI: −13.08, −7.29, p < 0.001; I² = 79.8%, p < 0.001), and GGT (ES = −5.88 IU/L, 95% CI: −7.09, −4.67, p = 0.009; I² = 0.0%, p = 0.591) levels. Probiotics have ameliorating effects on ALT, AST, and GGT levels in patients with NAFLD. Overall, Probiotics could be recommended as an adjuvant therapeutic method for the management of NAFLD.

Effects of Synbiotics, Probiotics, and Prebiotics on Liver Enzymes of Patients With Non-alcoholic Fatty Liver Disease: A Systematic Review and Network Meta-Analysis

Background

A systematic review and network meta-analysis was primarily conducted to compare the effects of synbiotics, probiotics, and prebiotics on aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Moreover, their effects on body mass index (BMI), waist circumference (WC), lipid profile, fasting blood sugar (FBS), and homeostatic model assessment-insulin resistance (HOMA-IR) of patients with non-alcoholic fatty liver disease (NAFLD) were investigated and analyzed as secondary outcomes.

Methods

The randomized controlled trials (RCTs), limited to the English language, were searched through PubMed, the Web of Science, Embase, CLINAHL Plus, and the Cochrane Library from inception to February 2, 2022. The eligible studies were reviewed and their risk-of-bias and heterogeneity were assessed. Both direct and indirect evidence were assembled using a random-effects model. The effects of the intervention were presented as weighted mean differences (WMD) with 95% confidence interval (95% CI).

Results

Of 3,864 identified records, a total of 1,389 patients with NAFLD from 26 RCTs were included in the analyses. Among these, 241 were diagnosed with non-alcoholic steatohepatitis. The quality assessment reported a moderate risk of bias from most studies. Among adult patients with NAFLD, when compared with placebo, synbiotics provided the largest effect on reductions of AST (-12.71 IU/L; 95% CI: -16.95, -8.47), WC (-2.26 cm; 95% CI: -2.98, -1.54), total cholesterol (-22.23 mg/dl; 95% CI: -29.55, -14.90), low-density lipoproteins (-17.72 mg/dl; 95% CI: -25.23, -10.22), and FBS (-6.75 mg/dl; 95% CI: -10.67, -2.84). Probiotics lowered ALT (-14.46 IU/L; 95% CI: -21.33, -7.59) and triglycerides (-20.97 mg/dl; 95% CI: -40.42, -1.53) the most. None had significant impact on BMI, high-density lipoproteins, and HOMA-IR changes.

Conclusion

Synbiotics and probiotics are likely to be the most potential effective treatments for AST and ALT reduction in adult patients with NAFLD, respectively. Although liver enzymes cannot exactly define the severity of NAFLD, unlike the results from biopsy or imaging tests, they are important indicators that can monitor the status of the disease and provide benefits for clinical management.

Systematic Review Registration

[https://www.crd.york.ac.uk/prospero/display_reco rd.php?ID], identifier [CRD42020200301].

Probiotic, prebiotic or symbiotic supplementation impacts on intestinal microbiota in patients with nonalcoholic fatty liver disease: A systematic review

ABSTRACT Background Supplementation with probiotics, prebiotics and symbiotics has shown positive effects on clinical markers and risk factors for non-alcoholic fatty liver disease (NAFLD). Objective To evaluate the effect of supplementation with probiotic, prebiotic or symbiotic on intestinal microbiota in NAFLD patients. Methods Two investigators conducted independently search for articles in the Medline databases, via PubMed, Web of Science, Embase, Scopus, Lilacs, Central Cochrane Library, Clinical Trials.gov and on the Ovid platform for the gray literature search. Results A total of 3,423 papers were identified by searching the electronic databases; 1,560 of them were duplicate and they were excluded; 1,825 articles were excluded after reading the title and abstract. A total of 39 articles were select to reading, however only four articles met the eligibility criteria to include in this systematic review. Three of the included studies that used prebiotic or symbiotic supplementation showed that after the intervention there were changes in the intestinal microbiota pattern. Only in one study such changes were not observed. A high risk of bias was observed in most assessments. Conclusion Although there is a possible change in the gut microbiota of individuals with NAFLD after supplementation with symbiotics or prebiotics, a clinical indication as part of NAFLD treatment is not yet possible.

Probiotics in Critically Ill Patients: An Umbrella Review

Objectives

Data sources

Study selection

Data extraction

Data synthesis

Conclusion

How to cite this article

Gut Microbiome in Non-Alcoholic Fatty Liver Disease: From Mechanisms to Therapeutic Role

Non-alcoholic fatty liver disease (NAFLD) is considered to be a significant health threat globally, and has attracted growing concern in the research field of liver diseases. NAFLD comprises multifarious fatty degenerative disorders in the liver, including simple steatosis, steatohepatitis and fibrosis. The fundamental pathophysiology of NAFLD is complex and multifactor-driven. In addition to viruses, metabolic syndrome and alcohol, evidence has recently indicated that the microbiome is related to the development and progression of NAFLD. In this review, we summarize the possible microbiota-based therapeutic approaches and highlight the importance of establishing the diagnosis of NAFLD through the different spectra of the disease via the gut–liver axis.

Probiotics for the improvement of metabolic profiles in patients with metabolic-associated fatty liver disease: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

This meta-analysis of randomized controlled trials (RCTs) was conducted to assess the efficacy of probiotics in the treatment of metabolic-associated fatty liver disease (MAFLD) mainly in terms of liver function, glucose and lipid metabolism, and inflammation.

METHODS

RCTs were searched on PubMed, Web of Science, Embase, and the Cochrane Library until June 2022. A meta-analysis was performed on the therapeutic efficacy of probiotics on liver function, glucose and lipid metabolism, and inflammatory biomarkers by using RevMan 5.4 software.

RESULTS

A total of 772 patients from 15 studies were included in the analysis. The methodological quality varied across studies. We found that adding probiotic therapies could reduce the levels of alanine aminotransferase [mean difference (MD): -11.76 (-16.06, -7.46), p < 0.00001], aspartate aminotransferase (MD: -9.08 (-13.60, -4.56), p < 0.0001], γ-glutamyltransferase [MD: -5.67 (-6.80, -4.54), p < 0.00001] and homeostasis model assessment-insulin resistance [MD: -0.62 (-1.08, -0.15), p = 0.01], in patients with MAFLD compared with those in control individuals. However, there was no statistically significant improvement in the levels of total cholesterol, triglycerides, low-density lipoprotein cholesterol, C-reactive protein and tumor necrosis factor α among patients with MAFLD. Subgroup analyses showed that other key factors, such as age, participants' baseline body mass index, and the duration of intervention, may influence probiotic therapy outcomes.

CONCLUSION

There is promising evidence that probiotic supplementation can reduce liver enzyme levels and regulate glycometabolism in patients with MAFLD. Further rigorous and long-term trials exploring these novel therapeutic perspectives are warranted to confirm these results.

The Effects of Probiotic Supplementation on Opioid-Related Disorder in Patients under Methadone Maintenance Treatment Programs

INTRODUCTION

Patients under methadone maintenance treatment programs (MMTPs) are susceptible to numerous complications (e.g., mental and metabolic disorders). This study evaluated the effects of probiotics on clinical symptoms, biomarkers of oxidative stress, inflammation, insulin resistance, and serum lipid content in patients receiving MMTPs.

MATERIALS AND METHODS

A randomized, double-blind, placebo-controlled trial was conducted among 70 patients receiving MMTPs to receive either 1.8 × 10⁹ CFU/day probiotics (n = 35) or placebo (n = 35) for 12 weeks. Clinical symptoms and metabolic profiles were measured before and after the intervention in patients receiving MMTPs.

RESULTS

Compared with the placebo group, probiotic supplementation resulted in a significant improvement in the severity of depression (P < 0.05). In addition, probiotic administration significantly decreased fasting plasma glucose (FPG), total cholesterol, and low-density lipoprotein cholesterol (LDL cholesterol) (P < 0.05). Furthermore, probiotics resulted in a significant reduction in high-sensitivity C-reactive protein (hs-CRP) and a significant elevation in total antioxidant capacity (TAC) and total glutathione (GSH) levels (P < 0.05).

CONCLUSION

Treatment with probiotics for 12 weeks to patients receiving MMTPs had beneficial effects on symptoms of depression, as well as several metabolic profiles. Clinical Trial Registration: this study was registered in the Iranian website (https://www.irct.ir) for clinical trials registration (https://fa.irct.ir/trial/46363/IRCT20170420033551N9). The registration date is March 22, 2020.

The impact of alteration in gut microbiome in the pathogenesis of nonalcoholic fatty liver disease

PURPOSE OF REVIEW

We have increasing evidence that alterations of the intestinal microbiome have a strong influence on human health. Previous work has demonstrated the association between changes in the microbiome and metabolic risk factors. One related area of interest is the relationship between dysbiosis and nonalcoholic fatty liver disease (NAFLD), as the global prevalence of NAFLD, and its resultant complications, increases.

RECENT FINDINGS

In this review, we summarize the hypothesized pathophysiology of dysbiosis-mediated progression of NAFLD, including promotion of an inflammatory intestinal environment, increased intestinal permeability, endogenous ethanol production, short-chain fatty acid production, secondary bile acid metabolism, and choline depletion. We also review potential therapeutic interventions of the microbiome to slow or prevent NAFLD progression, including antibiotics, probiotics, prebiotics, fecal microbiota transplant, and farnesoid × receptor agonism.

SUMMARY

Much of the evidence supporting dysbiosis-mediated NAFLD progression has been gathered in high-quality animal trials. There remains a need for additional observational and randomized controlled trials in humans to establish causality between the suspected factors and pathogenesis of NAFLD.

Novel approaches to intervene gut microbiota in the treatment of chronic liver diseases

Recent investigations of gut microbiota have contributed to understanding of the critical role of microbial community in pathophysiology. Dysbiosis not only causes disturbance directly to the gastrointestinal tract but also affects the liver through gut-liver axis. Various types of dysbiosis have been documented in alcoholic liver disease (ALD), nonalcoholic fatty liver disease, autoimmune hepatitis (AIH), primary sclerosing cholangitis, and may be crucial for the initiation, progression, or deterioration to end-stage liver disease. A few microbial species have been identified as the causal factors leading to these chronic illnesses that either do not have clear etiologies or lack effective treatment. Notably, cytolysin-producing Enterococcus faecalis, Klebsiella pneumoniae and Enterococcus gallinarum were defined for ALD, NASH, and AIH, respectively. These groundbreaking discoveries drive a rapid development in innovative therapeutics, such as fecal microbial transplantation and implementation of specific bacteriophages in addition to prebiotics, probiotics, or synbiotics for intervention of dysbiosis. Although most emerging interventions are in preclinical development or early clinical trials, a better delineation of specific dysbiosis in these disorders at metabolic, immunogenic, or molecular levels in establishing particular causal effects aids in modulating or correcting the microbial community which is the part of daily life for human being.

Probiotics and Prebiotics as a Strategy for Non-Alcoholic Fatty Liver Disease, a Narrative Review

Non-alcoholic fatty liver disease (NAFLD) is a chronic non-communicable disease, with a prevalence of 25% worldwide. This pathology is a multifactorial illness, and is associated with different risks factors, including hypertension, hyperglycemia, dyslipidemia, and obesity. Beside these predisposing features, NAFLD has been related to changes in the microbiota, which favor the disease progression. In this context, the modulation of the gut microbiota has emerged as a new therapeutic target for the prophylaxis and treatment of NAFLD. This review describes the changes in the gut microbiota associated with NAFLD and the effect of probiotics, prebiotics, and synbiotics on the gut microbiota, liver damage, anthropometric parameters, blood lipids, inflammation markers and insulin resistance in these patients.

Nutritional supplementation for nonalcohol-related fatty liver disease: a network meta-analysis

BACKGROUND

The prevalence of non-alcohol-related fatty liver disease (NAFLD) varies between 19% and 33% in different populations. NAFLD decreases life expectancy and increases risks of liver cirrhosis, hepatocellular carcinoma, and the requirement for liver transplantation. Uncertainty surrounds relative benefits and harms of various nutritional supplements in NAFLD. Currently no nutritional supplement is recommended for people with NAFLD.

OBJECTIVES

• To assess the benefits and harms of different nutritional supplements for treatment of NAFLD through a network meta-analysis • To generate rankings of different nutritional supplements according to their safety and efficacy SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, Science Citation Index Expanded, Conference Proceedings Citation Index-Science, the World Health Organization International Clinical Trials Registry Platform, and trials registers until February 2021 to identify randomised clinical trials in people with NAFLD.

SELECTION CRITERIA

We included only randomised clinical trials (irrespective of language, blinding, or status) for people with NAFLD, irrespective of method of diagnosis, age and diabetic status of participants, or presence of non-alcoholic steatohepatitis (NASH). We excluded randomised clinical trials in which participants had previously undergone liver transplantation.

DATA COLLECTION AND ANALYSIS

We performed a network meta-analysis with OpenBUGS using Bayesian methods whenever possible and calculated differences in treatments using hazard ratios (HRs), odds ratios (ORs), and rate ratios with 95% credible intervals (CrIs) based on an available-case analysis, according to National Institute of Health and Care Excellence Decision Support Unit guidance.

MAIN RESULTS

We included in the review a total of 202 randomised clinical trials (14,200 participants). Nineteen trials were at low risk of bias. A total of 32 different interventions were compared in these trials. A total of 115 trials (7732 participants) were included in one or more comparisons. The remaining trials did not report any of the outcomes of interest for this review. Follow-up ranged from 1 month to 28 months. The follow-up period in trials that reported clinical outcomes was 2 months to 28 months. During this follow-up period, clinical events related to NAFLD such as mortality, liver cirrhosis, liver decompensation, liver transplantation, hepatocellular carcinoma, and liver-related mortality were sparse. We did not calculate effect estimates for mortality because of sparse data (zero events for at least one of the groups in the trial). None of the trials reported that they measured overall health-related quality of life using a validated scale. The evidence is very uncertain about effects of interventions on serious adverse events (number of people or number of events). We are very uncertain about effects on adverse events of most of the supplements that we investigated, as the evidence is of very low certainty. However, people taking PUFA (polyunsaturated fatty acid) may be more likely to experience an adverse event than those not receiving an active intervention (network meta-analysis results: OR 4.44, 95% CrI 2.40 to 8.48; low-certainty evidence; 4 trials, 203 participants; direct evidence: OR 4.43, 95% CrI 2.43 to 8.42). People who take other supplements (a category that includes nutritional supplements other than vitamins, fatty acids, phospholipids, and antioxidants) had higher numbers of adverse events than those not receiving an active intervention (network meta-analysis: rate ratio 1.73, 95% CrI 1.26 to 2.41; 6 trials, 291 participants; direct evidence: rate ratio 1.72, 95% CrI 1.25 to 2.40; low-certainty evidence). Data were sparse (zero events in all groups in the trial) for liver transplantation, liver decompensation, and hepatocellular carcinoma. So, we did not perform formal analysis for these outcomes. The evidence is very uncertain about effects of other antioxidants (antioxidants other than vitamins) compared to no active intervention on liver cirrhosis (HR 1.68, 95% CrI 0.23 to 15.10; 1 trial, 99 participants; very low-certainty evidence). The evidence is very uncertain about effects of interventions in any of the remaining comparisons, or data were sparse (with zero events in at least one of the groups), precluding formal calculations of effect estimates. Data were probably because of the very short follow-up period (2 months to 28 months). It takes follow-up of 8 to 28 years to detect differences in mortality between people with NAFLD and the general population. Therefore, it is unlikely that differences in clinical outcomes are noted in trials providing less than 5 to 10 years of follow-up.

AUTHORS' CONCLUSIONS

The evidence indicates considerable uncertainty about effects of nutritional supplementation compared to no additional intervention on all clinical outcomes for people with non-alcohol-related fatty liver disease. Accordingly, high-quality randomised comparative clinical trials with adequate follow-up are needed. We propose registry-based randomised clinical trials or cohort multiple randomised clinical trials (study design in which multiple interventions are trialed within large longitudinal cohorts of patients to gain efficiencies and align trials more closely to standard clinical practice) comparing interventions such as vitamin E, prebiotics/probiotics/synbiotics, PUFAs, and no nutritional supplementation. The reason for the choice of interventions is the impact of these interventions on indirect outcomes, which may translate to clinical benefit. Outcomes in such trials should be mortality, health-related quality of life, decompensated liver cirrhosis, liver transplantation, and resource utilisation measures including costs of intervention and decreased healthcare utilisation after minimum follow-up of 8 years (to find meaningful differences in clinically important outcomes).

Minor Changes in the Composition and Function of the Gut Microbiota During a 12-Week Whole Grain Wheat or Refined Wheat Intervention Correlate with Liver Fat in Overweight and Obese Adults

BACKGROUND

Whole grain wheat (WGW) products are advocated as a healthy choice when compared with refined wheat (RW). One proposed mechanism for these health benefits is via the microbiota, because WGW contains multiple fibers. WGW consumption has been proposed to ameliorate nonalcoholic fatty liver disease, in which microbiota might play a role.

OBJECTIVES

We investigated the effect of WGW compared with RW intervention on the fecal microbiota composition and functionality, and correlated intervention-induced changes in bacteria with changes in liver health parameters in adults with overweight or obesity.

METHODS

We used data of a 12-wk double-blind, randomized, controlled, parallel trial to examine the effects of a WGW (98 g/d) or RW (98 g/d) intervention on the secondary outcomes fecal microbiota composition, predicted microbiota functionality, and stool consistency in 37 women and men (aged 45-70 y, BMI 25-35 kg/m2). The changes in microbiota composition, measured using 16S ribosomal RNA gene sequencing, after a 12-wk intervention were analyzed with nonparametric tests, and correlated with changes in liver fat and circulating concentrations of liver enzymes including alanine transaminase, aspartate transaminase, γ-glutamyltransferase, and serum amyloid A.

RESULTS

The WGW intervention increased the mean (± SD) relative abundances of Ruminococcaceae_UCG-014 (baseline: 2.2 ± 4.6%, differential change over time (Δ) 0.51 ± 4.2%), Ruminiclostridium_9 (baseline: 0.065 ± 0.11%, Δ 0.054 ± 0.14%), and Ruminococcaceae_NK4A214_group (baseline: 0.37 ± 0.56%, Δ 0.17 ± 0.83%), and also the predicted pathway acetyl-CoA fermentation to butyrate II (baseline: 0.23 ± 0.062%, Δ 0.035 ± 0.059%), compared with the RW intervention (P values <0.05). A change in Ruminococcaceae_NK4A214_group was positively correlated with the change in liver fat, in both the WGW (ρ = 0.54; P = 0.026) and RW (ρ = 0.67; P = 0.024) groups.

CONCLUSIONS

In middle-aged overweight and obese adults, a 12-wk WGW intervention increased the relative abundance of a number of bacterial taxa from the family Ruminococcaceae and increased predicted fermentation pathways when compared with an RW intervention. Potential protective health effects of replacement of RW by WGW on metabolic organs, such as the liver, via modulation of the microbiota, deserve further investigation.This trial was registered at clinicaltrials.gov as NCT02385149.

Nutritional Approach Targeting Gut Microbiota in NAFLD-To Date

Non-alcoholic fatty liver disease (NAFLD) is a significant clinical and epidemiological problem that affects around 25% of the adult global population. A large body of clinical evidence highlights that NAFLD is associated with increased liver-related morbidity and mortality and an increased risk of cardiovascular disease, extrahepatic cancers, type 2 diabetes, and chronic kidney disease. Recently, a series of studies revealed the pivotal role of gut microbiota (GM) dysbiosis in NAFLD's pathogenesis. The GM plays an essential role in different metabolic pathways, including the fermentation of diet polysaccharides, energy harvest, choline regulation, and bile acid metabolism. One of the most critical factors in GM stabilization is the diet; therefore, nutritional therapyappearsto be a promising tool in NAFLD therapy. This paper aims to review the current knowledge regardingthe nutritional approach and its implications with GM and NAFLD treatment. We discuss the positive impact of probiotics, prebiotics, and symbiotics in a reverse dysbiosis state in NAFLD and show the potential beneficial effects of bioactive substances from the diet. The full description of the mechanism of action and comprehensive examination of the impact of nutritional interventions on GM modulation may, in the future, be a simple but essential tool supporting NAFLD therapy.

Insights into the Impact of Microbiota in the Treatment of NAFLD/NASH and Its Potential as a Biomarker for Prognosis and Diagnosis

Non-alcoholic fatty liver disease (NAFLD) is an increasing cause of chronic liver illness associated with obesity and metabolic disorders, such as hypertension, dyslipidemia, or type 2 diabetes mellitus. A more severe type of NAFLD, non-alcoholic steatohepatitis (NASH), is considered an ongoing global health threat and dramatically increases the risks of cirrhosis, liver failure, and hepatocellular carcinoma. Several reports have demonstrated that liver steatosis is associated with the elevation of certain clinical and biochemical markers but with low predictive potential. In addition, current imaging methods are inaccurate and inadequate for quantification of liver steatosis and do not distinguish clearly between the microvesicular and the macrovesicular types. On the other hand, an unhealthy status usually presents an altered gut microbiota, associated with the loss of its functions. Indeed, NAFLD pathophysiology has been linked to lower microbial diversity and a weakened intestinal barrier, exposing the host to bacterial components and stimulating pathways of immune defense and inflammation via toll-like receptor signaling. Moreover, this activation of inflammation in hepatocytes induces progression from simple steatosis to NASH. In the present review, we aim to: (a) summarize studies on both human and animals addressed to determine the impact of alterations in gut microbiota in NASH; (b) evaluate the potential role of such alterations as biomarkers for prognosis and diagnosis of this disorder; and (c) discuss the involvement of microbiota in the current treatment for NAFLD/NASH (i.e., bariatric surgery, physical exercise and lifestyle, diet, probiotics and prebiotics, and fecal microbiota transplantation).

The interplay between host cellular and gut microbial metabolism in NAFLD development and prevention

Metabolism regulation centred on insulin resistance is increasingly important in nonalcoholic fatty liver disease (NAFLD). This review focuses on the interactions between the host cellular and gut microbial metabolism during the development of NAFLD. The cellular metabolism of essential nutrients, such as glucose, lipids and amino acids, is reconstructed with inflammation, immune mechanisms and oxidative stress, and these alterations modify the intestinal, hepatic and systemic environments, and regulate the composition and activity of gut microbes. Microbial metabolites, such as short-chain fatty acids, secondary bile acids, protein fermentation products, choline and ethanol and bacterial toxicants, such as lipopolysaccharides, peptidoglycans and bacterial DNA, play vital roles in NAFLD. The microbe-metabolite relationship is crucial for the modulation of intestinal microbial composition and metabolic activity. The intestinal microbiota and their metabolites participate in epithelial cell metabolism via a series of cell receptors and signalling pathways and remodel the metabolism of various cells in the liver via the gut-liver axis. Microbial metabolic manipulation is a promising strategy for NAFLD prevention, but larger-sampled clinical trials are required for future application.