A randomised placebo controlled trial of VSL#3® probiotic on biomarkers of cardiovascular risk and liver injury in non-alcoholic fatty liver disease

Clinical improvement effect of regulating gut microbiota on metabolic dysfunction-associated steatotic liver disease: Systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) is constantly rising globally. There are barely any effective medications or supplements for the management of MASLD. We aim to systematically evaluate the most current evidence for gut microbiota-regulating supplements in patients with MASLD.

METHODS

We searched multiple electronic data for randomized controlled trials (RCTs) published from January 1, 2012, to July 15, 2023. The intervention measures included probiotics, prebiotics, synbiotics, antibiotics, and fecal microbiota transplantation (FMT). The control group was treated with a placebo or usual care. The intervention duration was divided into two periods (>12 weeks and ≤12 weeks). Adequate evaluation data for antibiotics and FMT have not been obtained. Therefore, the other three microbiota regulators are the primary evaluation measures in this study.

RESULTS

We found that probiotics alone could not improve clinical indicators in MASLD patients. However, synbiotics exhibited an improvement in reducing liver steatosis, TNF-ɑ levels, and increasing HDL-c levels, and the inflammatory markers of liver cells (ALT and AST) were also improved. For the effective intervention duration, this systematic review suggested that around 12 weeks is an ideal intervention cycle for MASLD patients.

CONCLUSIONS

This meta-analysis supported the modulation of gut microbiota with synbiotics in the management of MASLD.

NAFLD/MASLD and the Gut-Liver Axis: From Pathogenesis to Treatment Options

Nonalcoholic fatty liver disease (NAFLD) poses an emerging threat topublic health. Nonalcoholic steatohepatitis (NASH) is reported to be the most rapidly rising cause of hepatocellular carcinoma in the western world. Recently, a new term has been proposed: metabolic dysfunction-associated steatotic liver disease (MASLD). The introduction of this new terminology has sparked a debate about the interchangeability of these terms. The pathogenesis of NAFLD/MASLD is thought to be multifactorial, involving both genetic and environmental factors. Among these factors, alterations in gut microbiota and gut dysbiosis have recently garnered significant attention. In this context, this review will further discuss the gut-liver axis, which refers to the bidirectional interaction between the human gut microbiota and the liver. Additionally, the therapeutic potential of probiotics, particularly next-generation probiotics and genetically engineered bacteria, will be explored. Moreover, the role of prebiotics, synbiotics, postbiotics, and phages as well as fecal microbiota transplantation will be analyzed. Particularly for lean patients with NAFLD/MASLD, who have limited treatment options, approaches that modify the diversity and composition of the gut microbiota may hold promise. However, due to ongoing safety concerns with approaches that modulate gut microbiota, further large-scale studies are necessary to better assess their efficacy and safety in treating NAFLD/MASLD.

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.

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.

Non-alcoholic fatty liver disease and gut microbial dysbiosis- underlying mechanisms and gut microbiota mediated treatment strategies

Non-alcoholic fatty liver disease (NAFLD) is by far the most prevalent form of liver disease worldwide. It's also the leading cause of liver-related hospitalizations and deaths. Furthermore, there is a link between obesity and NAFLD risk. A projected 25% of the world's population grieves from NAFLD, making it the most common chronic liver disorder. Several factors, such as obesity, oxidative stress, and insulin resistance, typically accompany NAFLD. Weight loss, lipid-lowering agents, thiazolidinediones, and metformin help prominently control NAFLD. Interestingly, pre-clinical studies demonstrate gut microbiota's potential causal role in NAFLD. Increased intestinal permeability and unhindered transport of microbial metabolites into the liver are the major disruptions due to gut microbiome dysbiosis, contributing to the development of NAFLD by dysregulating the gut-liver axis. Hence, altering the pathogenic bacterial population using probiotics, prebiotics, synbiotics, and fecal microbiota transplantation (FMT) could benefit patients with NAFLD. Therefore, it is crucial to acknowledge the importance of microbiota-mediated therapeutic approaches for NAFLD and comprehend the underlying mechanisms that establish a connection between NAFLD and gut microbiota. This review provides a comprehensive overview of the affiliation between dysbiosis of gut microbiota and the progress of NAFLD, as well as the potential benefits of prebiotic, probiotic, synbiotic supplementation, and FMT in obese individuals with NAFLD.

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.

Therapeutic modulation of the liver immune microenvironment

Inflammation is a hallmark of progressive liver diseases such as chronic viral or immune-mediated hepatitis, alcohol-associated liver disease, and NAFLD. Preclinical and clinical studies have provided robust evidence that cytokines and related cellular stress sensors in innate and adaptive immunity orchestrate hepatic disease processes. Unresolved inflammation and liver injury result in hepatic scarring, fibrosis, and cirrhosis, which may culminate in HCC. Liver diseases are accompanied by gut dysbiosis and a bloom of pathobionts, fueling hepatic inflammation. Anti-inflammatory strategies are extensively used to treat human immune-mediated conditions beyond the liver, while evidence for immunomodulatory therapies and cell therapy-based strategies in liver diseases is only emerging. The development and establishment of novel immunomodulatory therapies for chronic liver diseases has been dampened by several clinical challenges, such as invasive monitoring of therapeutic efficacy with liver biopsy in clinical trials and risk of DILI in several studies. Such aspects prevented advancements of novel medical therapies for chronic inflammatory liver diseases. New concepts modulating the liver immune environment are studied and eagerly awaited to improve the management of chronic liver diseases in the future.

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.

Prebiotics and Probiotics: Therapeutic Tools for Nonalcoholic Fatty Liver Disease

Alterations in the gut-liver axis and changes in the gut microbiome are among the risk factors for the pathogenesis of non-alcoholic fatty liver disease (NAFLD). These patients show increased bacterial overgrowth in the small intestine and impaired intestinal permeability. Therefore, therapeutic options such as probiotics or prebiotics have been investigated to modulate intestinal microbiota composition to improve NAFLD. Most in vivo and in vitro probiotic studies have focused on reducing hepatic fat accumulation. The beneficial effects of probiotics on NAFLD have been demonstrated in animal models, and the most widely used microorganisms are those of the Lactobacillus and Bifidobacterium genera. In animal models, probiotics help restore the intestinal microbiota and improve the integrity of the intestinal barrier. This narrative review summarizes published evidence and the likely benefits of probiotics and prebiotics as a therapeutic option for patients with NAFLD.

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.

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.

Type 2 Diabetes Mellitus, Non-Alcoholic Fatty Liver Disease, and Metabolic Repercussions: The Vicious Cycle and Its Interplay with Inflammation

The prevalence of metabolic-related disorders, such as non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (DM2), has been increasing. Therefore, developing improved methods for the prevention, treatment, and detection of these two conditions is also necessary. In this study, our primary focus was on examining the role of chronic inflammation as a potential link in the pathogenesis of these diseases and their interconnections. A comprehensive search of the PubMed database using keywords such as "non-alcoholic fatty liver disease", "type 2 diabetes mellitus", "chronic inflammation", "pathogenesis", and "progression" yielded 177 relevant papers for our analysis. The findings of our study revealed intricate relationships between the pathogenesis of NAFLD and DM2, emphasizing the crucial role of inflammatory processes. These connections involve various molecular functions, including altered signaling pathways, patterns of gene methylation, the expression of related peptides, and up- and downregulation of several genes. Our study is a foundational platform for future research into the intricate relationship between NAFLD and DM2, allowing for a better understanding of the underlying mechanisms and the potential for introducing new treatment standards.

How far are we from an approved drug for non-alcoholic steatohepatitis?

INTRODUCTION

Metabolic associated fatty liver disease (MAFLD) previously known but still debatable, as non-alcoholic fatty liver disease (NAFLD) is one of the main causes of chronic liver disease and subsequent cirrhosis worldwide, accounting for around 30% of liver diseases. The change in its nomenclature has been brought about by the novel discoveries regarding its pathogenesis, in which metabolic dysfunction plays the most important role. It is widely known that for every disease, the treatment should always be targeted toward the underlying etiology and pathogenesis.

AREAS COVERED

MAFLD/NAFLD pathogenesis is heterogeneous, and includes multiple gene polymorphisms, presence of insulin resistance, as well as concomitant diseases that contribute to the disease onset and progression. As a result of this, even though lifestyle modification (owing to metabolic abnormalities) is the first line of treatment, multiple drugs have been tested to target each of the known pathways leading to MAFLD/NAFLD and progression of steatohepatitis. We aim to review the most relevant information regarding previous and ongoing research and recommendations regarding treatment of MAFLD/NAFLD.

EXPERT OPINION

Combination therapies associated to weight loss and exercise will be the optimal approach for these patients. It is important to evaluate each patient to select the specific combination according to patient characteristics.

The effects of probiotics on VCAM-1 and ICAM-1: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

We performed the present systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the effects of probiotics on intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) levels in adults.

METHODS

A systematic search current to April 2022 was performed in MEDLINE, EMBASE, and Cochrane Database using relevant keywords to detect eligible articles. A random-effects model was used to estimate the standardized mean difference (SMD) and 95% confidence interval (95% CI).

RESULTS

Six eligible trials were included in the final analysis. The pooled analysis revealed that there was a significant reduction in VCAM-1 from baseline to post-probiotic course with standardized mean difference [SMD: -0.66 ng/ml; 95% CI: -1.09, -0.23 ng/ml; P = 0.003]. The effects of probiotic intake on VCAM-1 were more pronounced when it was received via supplements [SMD: -0.61 ng/ml; 95% CI: -1.08, -0.14 ng/ml; P = 0.010], for 12 weeks [SMD: -0.60 ng/ml; 95% CI: -1.09, -0.12 ng/ml; P = 0.014] and when it was prescribed for individuals with metabolic syndrome [SMD: -0.79 ng/ml; 95% CI: -1.40, -0.19 ng/ml; P = 0.010]. Moreover, VCAM-1 levels were decreased in the subgroup of multispecies probiotic regiments [SMD: -0.71 ng/ml; 95% CI: -1.38, -0.04 ng/ml; P = 0.039].

CONCLUSION

Our study demonstrates potential beneficial effects of probiotics on VCAM-1 in adults. However, more larger-scale, long-time RCTs are needed to confirm the accurate effect of probiotics on endothelial dysfunction biomarkers.

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.

The Effects of Probiotics on Small Intestinal Microbiota Composition, Inflammatory Cytokines and Intestinal Permeability in Patients with Non-Alcoholic Fatty Liver Disease

The prevalence of non-alcoholic fatty liver disease (NAFLD) has soared globally. As our understanding of the disease grows, the role of the gut-liver axis (GLA) in NAFLD pathophysiology becomes more apparent. Hence, we focused mainly on the small intestinal area to explore the role of GLA. We looked at how multi-strain probiotics (MCP^® BCMC^® strains) containing six different Lactobacillus and Bifidobacterium species affected the small intestinal gut microbiota, inflammatory cytokines, and permeability in NAFLD patients. After six months of supplementation, biochemical blood analysis did not show any discernible alterations in either group. Five predominant phyla known as Actinobacteria, Proteobacteria, Firmicutes, Bacteroidota and Fusobacteria were found in NAFLD patients. The probiotics group demonstrated a significant cluster formation of microbiota composition through beta-diversity analysis (p < 0.05). This group significantly reduced three unclassifiable species: unclassified_Proteobacteria, unclassified_Streptococcus, and unclassified_Stenotrophomonas. In contrast, the placebo group showed a significant increase in Prevotella_melaninogenica and Rothia_mucilaginosa, which were classified as pathogens. Real-time quantitative PCR analysis of small intestinal mucosal inflammatory cytokines revealed a significant decrease in IFN-γ (-7.9 ± 0.44, p < 0.0001) and TNF-α (-0.96 ± 0.25, p < 0.0033) in the probiotics group but an increase in IL-6 (12.79 ± 2.24, p < 0.0001). In terms of small intestinal permeability analysis, the probiotics group, unfortunately, did not show any positive changes through ELISA analysis. Both probiotics and placebo groups exhibited a significant increase in the level of circulating zonulin (probiotics: 107.6 ng/mL ± 124.7, p = 0.005 vs. placebo: 106.9 ng/mL ± 101.3, p = 0.0002) and a significant decrease in circulating zonula occluden-1 (ZO-1) (probiotics: -34.51 ng/mL ± 18.38, p < 0.0001 vs. placebo: -33.34 ng/mL ± 16.62, p = 0.0001). The consumption of Lactobacillus and Bifidobacterium suggested the presence of a well-balanced gut microbiota composition. Probiotic supplementation improves dysbiosis in NAFLD patients. This eventually stabilised the expression of inflammatory cytokines and mucosal immune function. To summarise, more research on probiotic supplementation as a supplement to a healthy diet and lifestyle is required to address NAFLD and its underlying causes.

Functional foods and dietary supplements in the management of non-alcoholic fatty liver disease: A systematic review and meta-analysis

Objective

In this systematic review and meta-analysis, we aimed to clarify the overall effects of functional foods and dietary supplements in non-alcoholic fatty liver disease (NAFLD) patients.

Methods

Randomized controlled trials (RCTs) published in PubMed, ISI Web of Science, Cochrane library, and Embase from January 1, 2000 to January 31, 2022 were systematically searched to assess the effects of functional foods and dietary supplements in patients with NAFLD. The primary outcomes were liver-related measures, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), and hepatic fibrosis and steatosis, while the secondary outcomes included body mass index (BMI), waist circumference (WC), triacylglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). These indexes were all continuous variables, so the mean difference (MD) was used for calculating the effect size. Random-effects or fixed-effects models were used to estimate the mean difference (MD). The risk of bias in all studies was assessed with guidance provided in the Cochrane Handbook for Systematic Reviews of Interventions.

Results

Twenty-nine articles investigating functional foods and dietary supplements [antioxidants (phytonutrients and coenzyme Q10) = 18, probiotics/symbiotic/prebiotic = 6, fatty acids = 3, vitamin D = 1, and whole grain = 1] met the eligibility criteria. Our results showed that antioxidants could significantly reduce WC (MD: -1.28 cm; 95% CI: -1.58, -0.99, P < 0.05), ALT (MD: -7.65 IU/L; 95% CI: -11.14, -4.16, P < 0.001), AST (MD: -4.26 IU/L; 95% CI: -5.76, -2.76, P < 0.001), and LDL-C (MD: -0.24 mg/dL; 95% CI: -0.46, -0.02, P < 0.05) increased in patients with NAFLD but had no effect on BMI, TG, and TC. Probiotic/symbiotic/prebiotic supplementation could decrease BMI (MD: -0.57 kg/m2; 95% CI: -0.72, -0.42, P < 0.05), ALT (MD: -3.96 IU/L; 95% CI: -5.24, -2.69, P < 0.001), and AST (MD: -2.76; 95% CI: -3.97, -1.56, P < 0.0001) levels but did not have beneficial effects on serum lipid levels compared to the control group. Moreover, the efficacy of fatty acids for treating NAFLD was full of discrepancies. Additionally, vitamin D had no significant effect on BMI, liver transaminase, and serum lipids, while whole grain could reduce ALT and AST but did not affect serum lipid levels.

Conclusion

The current study suggests that antioxidant and probiotic/symbiotic/prebiotic supplements may be a promising regimen for NAFLD patients. However, the usage of fatty acids, vitamin D, and whole grain in clinical treatment is uncertain. Further exploration of the efficacy ranks of functional foods and dietary supplements is needed to provide a reliable basis for clinical application.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier: CRD42022351763.

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.

Gut dysbiosis in nonalcoholic fatty liver disease: pathogenesis, diagnosis, and therapeutic implications

The incidence of nonalcoholic fatty liver disease (NAFLD) is increasing recently and has become one of the most common clinical liver diseases. Since the pathogenesis of NAFLD has not been completely elucidated, few effective therapeutic drugs are available. As the "second genome" of human body, gut microbiota plays an important role in the digestion, absorption and metabolism of food and drugs. Gut microbiota can act as an important driver to advance the occurrence and development of NAFLD, and to accelerate its progression to cirrhosis and hepatocellular carcinoma. Growing evidence has demonstrated that gut microbiota and its metabolites directly affect intestinal morphology and immune response, resulting in the abnormal activation of inflammation and intestinal endotoxemia; gut dysbiosis also causes dysfunction of gut-liver axis via alteration of bile acid metabolism pathway. Because of its composition diversity and disease-specific expression characteristics, gut microbiota holds strong promise as novel biomarkers and therapeutic targets for NAFLD. Intervening intestinal microbiota, such as antibiotic/probiotic treatment and fecal transplantation, has been a novel strategy for preventing and treating NAFLD. In this article, we have reviewed the emerging functions and association of gut bacterial components in different stages of NAFLD progression and discussed its potential implications in NAFLD diagnosis and therapy.

The effects of supplementation of probiotics, prebiotics, or synbiotics on patients with non-alcoholic fatty liver disease: A meta-analysis of randomized controlled trials

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease. Research on the efficacy of probiotics, prebiotics, and synbiotics on NAFLD patients continues to be inconsistent. The purpose of this study is to evaluate the effectiveness of these microbial therapies on NAFLD.

METHODS

Eligible randomized-controlled trials reporting the effect of probiotics, prebiotics, or synbiotics in NAFLD were searched in PubMed, Web of Science, Embase, Google scholar, and CNKI databases from 2020 to Jul 2022. The changes in the outcomes were analyzed using standard mean difference (SMD) and 95% confidence intervals (CIs) with a random- or fixed-effects model to examine the effect of microbial therapies. Subgroup analysis, influence and publication bias analysis were also performed. The quality of the eligible studies was evaluated using the Cochrane Risk of Bias Tool.

RESULTS

Eleven studies met the inclusion criteria involving 741 individuals. Microbial therapies could improve liver steatosis, total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL-c), alanine aminotransferase (ALT), alkaline phosphatase (ALP), glutamyl transpeptidase (GGT), and homeostasis model assessment-insulin resistance (HOMAI-R) (all P < 0.05). But microbial therapies could not ameliorate body mass index (BMI), energy, carbohydrate, fat intake, fasting blood sugar, HbA1c, insulin, high-sensitivity C-reactive protein (hs-CRP), and hepatic fibrosis of patients with NAFLD.

CONCLUSION

Probiotics, prebiotics, and synbiotics supplementation can potentially improve liver enzymes, lipid profiles, and liver steatosis in patients with NAFLD.

Gut microbiota–mitochondrial inter-talk in non-alcoholic fatty liver disease

The increasing prevalence of non-alcoholic fatty liver disease (NAFLD), which is a progressive disease, has exerted huge a healthcare burden worldwide. New investigations have suggested that the gut microbiota closely participates in the progression of NAFLD through the gut–liver axis or gut–brain–liver axis. The composition of the microbiota can be altered by multiple factors, primarily dietary style, nutritional supplements, or exercise. Recent evidence has revealed that gut microbiota is involved in mitochondrial biogenesis and energy metabolism in the liver by regulating crucial transcription factors, enzymes, or genes. Moreover, microbiota metabolites can also affect mitochondrial oxidative stress function and swallow formation, subsequently controlling the inflammatory response and regulating the levels of inflammatory cytokines, which are the predominant regulators of NAFLD. This review focuses on the changes in the composition of the gut microbiota and metabolites as well as the cross-talk between gut microbiota and mitochondrial function. We thus aim to comprehensively explore the potential mechanisms of gut microbiota in NAFLD and potential therapeutic strategies targeting NAFLD management.

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.

Sex Differences in Cardiovascular Impact of Early Metabolic Impairment: Interplay between Dysbiosis and Adipose Inflammation

The evolving view of gut microbiota has shifted toward describing the colonic flora as a dynamic organ in continuous interaction with systemic physiologic processes. Alterations of the normal gut bacterial profile, known as dysbiosis, has been linked to a wide array of pathologies. Of particular interest is the cardiovascular-metabolic disease continuum originating from positive energy intake and high-fat diets. Accumulating evidence suggests a role for sex hormones in modulating the gut microbiome community. Such a role provides an additional layer of modulation of the early inflammatory changes culminating in negative metabolic and cardiovascular outcomes. In this review, we will shed the light on the role of sex hormones in cardiovascular dysfunction mediated by high-fat diet-induced dysbiosis, together with the possible involvement of insulin resistance and adipose tissue inflammation. Insights into novel therapeutic interventions will be discussed as well. SIGNIFICANCE STATEMENT: Increasing evidence implicates a role for dysbiosis in the cardiovascular complications of metabolic dysfunction. This minireview summarizes the available data on the sex-based differences in gut microbiota alterations associated with dietary patterns leading to metabolic impairment. A role for a differential impact of adipose tissue inflammation across sexes in mediating the cardiovascular detrimental phenotype following diet-induced dysbiosis is proposed. Better understanding of this pathway will help introduce early approaches to mitigate cardiovascular deterioration in metabolic disease.

Probiotic Therapy With VSL#3® in Patients With NAFLD: A Randomized Clinical Trial

Aim

To evaluate if VSL#3^® [a high-concentration multi-strain probiotic mix containing one strain of Streptococcus thermophilus BT01, three strains of Bifidobacteria (B. breve BB02; B. animalis subspecies [subsp.] lactis BL03, previously identified as B. longum BL03; and B. animalis subsp. lactis BI04, previously identified as B. infantis BI04), and four strains of Lactobacilli (L. acidophilus BA05, L. plantarum BP06, L. paracasei BP07, and L. helveticus BD08, previously identified as L. delbrueckii subsp. bulgaricus BD08)] therapy could improve hepatic parameters.

Methods

We enrolled 60 Caucasian patients aged ≥ 18 years of either sex with the diagnosis of non-alcoholic fatty liver disease (NAFLD), according to practice guidance, in a double-blind, placebo-controlled study. Patients were randomized to take placebo or VSL#3^®, 2 sachets/day in the morning for 3 months. VSL#3^® and placebo were self-administered.

Results

We did not observe any change in body mass index (BMI), circumferences, fasting plasma glucose (FPG), total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C), and adiponectin (ADN) with neither treatment. A statistically significant triglycerides (Tg) decrease (p < 0.05 vs. baseline, and p < 0.05 vs. placebo, respectively) and high-sensitivity C-reactive protein (Hs-CRP) decrease (p < 0.05 vs. baseline) was observed in the group of patients being treated with VSL#3^® compared with placebo. Transaminases and gamma-glutamyltransferase (γ-GT) were significantly reduced in VSL#3^® group (p < 0.05 vs. baseline and placebo, respectively) compared with the placebo group. Aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio and hepatic steatosis index (HSI) were significantly lower than the VSL#3^® group (p < 0.05 vs. baseline and placebo, respectively) compared with the placebo group. All patients reported an improvement or the disappearance of hepatic steatosis.

Conclusion

Probiotic therapy with VSL#3^® ameliorates hepatic parameters and echography grading, while reducing Tg and the inflammatory status, without any difference between men and women.

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].

Implications of microbe-mediated crosstalk in the gut: Impact on metabolic diseases

Metabolic diseases continue to afflict most of the U.S. population. Advancements in gut microbiota research have led to the discovery of various functional roles of microorganisms that influence the development of obesity and co-morbidities including type 2 diabetes, non-alcoholic fatty liver disease and cardiovascular disease. Many mechanisms behind these host-microbe interactions stem from processes involving the intestinal epithelium including lipid metabolism. Thus, the purpose of this review is to discuss gut microbe-mediated changes in intestinal physiology and lipid metabolism that contribute to obesity, type 2 diabetes, non-alcoholic fatty liver disease and cardiovascular disease. Within each disease state, the causal role of bacteria in both driving disease development and protecting against metabolic disease will be discussed.

Usefulness of Probiotics in the Management of NAFLD: Evidence and Involved Mechanisms of Action from Preclinical and Human Models

The present review aims at analyzing the current evidence regarding probiotic administration for non-alcoholic fatty liver disease (NAFLD) management. Additionally, the involved mechanisms of action modulated by probiotic administration, as well as the eventual limitations of this therapeutic approach and potential alternatives, are discussed. Preclinical studies have demonstrated that the administration of single-strain probiotics and probiotic mixtures effectively prevents diet-induced NAFLD. In both cases, the magnitude of the described effects, as well as the involved mechanisms of action, are comparable, including reduced liver lipid accumulation (due to lipogenesis downregulation and fatty acid oxidation upregulation), recovery of gut microbiota composition and enhanced intestinal integrity. Similar results have also been reported in clinical trials, where the administration of probiotics proved to be effective in the treatment of NAFLD in patients featuring this liver condition. In this case, information regarding the mechanisms of action underlying probiotics-mediated hepatoprotective effects is scarcer (mainly due to the difficulty of liver sample collection). Since probiotics administration represents an increased risk of infection in vulnerable subjects, much attention has been paid to parabiotics and postbiotics, which seem to be effective in the management of several metabolic diseases, and thus represent a suitable alternative to probiotic usage.

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.

New progress in research of intestinal microbiota in fatty liver disease

At present, intestinal microbiota has become one of hot issues in current research. Fatty liver disease refers to the pathology of excessive accumulation of fat in liver cells due to various reasons. Fatty liver disease can cause damage to the normal structure and physiological and biochemical functions of the liver, and lead to the appearance of clinical symptoms. And it generally includes two categories: Non-alcoholic fatty liver disease and alcoholic liver disease. Changes in intestinal flora and intestinal permeability can further affect the development of fatty liver disease through the gut-liver axis. Similarly, intestinal microbiota also changes to varying degrees during the occurrence and development of fatty liver disease. This paper mainly introduces the relationship between the gut-liver axis and fatty liver disease, changes of intestinal flora during the progression of fatty liver disease, and new advances in the application of probiotics in the treatment of fatty liver disease.

Nonalcoholic Fatty Liver Disease in Children

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. It represents a spectrum of disease from simple hepatic steatosis to steatohepatitis that may develop into progressive hepatic fibrosis and even cirrhosis. NAFLD is the most rapidly increasing indication for liver transplantation in adults. In children, the incidence of NAFLD has also increased over the past decade. Although the majority of children with NAFLD are overweight or obese, there is an increasing subset of children with normal body mass index with so-called lean NAFLD. NAFLD in children is associated with several extrahepatic manifestations, including hyperlipidemia, insulin resistance, and obstructive sleep apnea. The pathogenesis of NAFLD in children involves a multifactorial interaction among genetics, in utero exposures, early childhood exposures, and ongoing nutritional exposures. Although there are some similarities between pediatric NAFLD and adult NAFLD, liver biopsies in children show histologic differences between the two. The current standard-of-care treatment of NAFLD in children is lifestyle change to decrease caloric intake and increase physical activity. There are no medications currently approved for the treatment of NAFLD in children. This article aims to summarize the current understanding of pediatric NAFLD and future directions for intervention and therapeutic aims.

Intestinal dysbiosis in nonalcoholic fatty liver disease (NAFLD): focusing on the gut-liver axis

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver disorders in humans, partly because it is closely related to metabolic disorders of the liver with increasing prevalence. NAFLD begins with hepatic lipid accumulation, which may cause inflammation and eventually lead to fibrosis in the liver. Numerous studies have demonstrated the close relationship between gut dysfunction (especially the gut microbiota and its metabolites) and the occurrence and progression of NAFLD. The bidirectional communication between the gut and liver, named the gut-liver axis, is mainly mediated by the metabolites derived from both the liver and gut through the biliary tract, portal vein, and systemic circulation. Herein, we review the effects of the gut-liver axis on the pathogenesis of NAFLD. We also comprehensively describe the potential molecular mechanisms from the perspective of the role of liver-derived metabolites and gut-related components in hepatic metabolism and inflammation and gut health, respectively. The study provides insights into the mechanisms underlying current summarizations that support the intricate interactions between a disordered gut and NAFLD and can provide novel strategies to lessen the prevalence and consequence of NAFLD.