Effects of Multistrain Probiotic Supplementation on Glycemic and Inflammatory Indices in Patients with Nonalcoholic Fatty Liver Disease: A Double-Blind Randomized Clinical Trial

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.

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.

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.

The effects of gut microbiome manipulation on glycemic indices in patients with non-alcoholic fatty liver disease: a comprehensive umbrella review

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a significant risk factor for non-alcoholic fatty liver disease (NAFLD). Increased fasting blood sugar (FBS), fasting insulin (FI), and insulin resistance (HOMA-IR) are observed in patients with NAFLD. Gut microbial modulation using prebiotics, probiotics, and synbiotics has shown promise in NAFLD treatment. This meta-umbrella study aimed to investigate the effects of gut microbial modulation on glycemic indices in patients with NAFLD and discuss potential mechanisms of action.

METHODS

A systematic search was conducted in PubMed, Web of Science, Scopus, and Cochrane Library until March 2023 for meta-analyses evaluating the effects of probiotics, prebiotics, and synbiotics on patients with NAFLD. Random-effect models, sensitivity analysis, and subgroup analysis were employed.

RESULTS

Gut microbial therapy significantly decreased HOMA-IR (ES: -0.41; 95%CI: -0.52, -0.31; P < 0.001) and FI (ES: -0.59; 95%CI: -0.77, -0.41; P < 0.001). However, no significant effect was observed on FBS (ES: -0.17; 95%CI: -0.36, 0.02; P = 0.082). Subgroup analysis revealed prebiotics had the most potent effect on HOMA-IR, followed by probiotics and synbiotics. For FI, synbiotics had the most substantial effect, followed by prebiotics and probiotics.

CONCLUSION

Probiotics, prebiotics, and synbiotics administration significantly reduced FI and HOMA-IR, but no significant effect was observed on FBS.

Probiotics ameliorate endocrine disorders via modulating inflammatory pathways: a systematic review

Probiotics has offered a new prospect to treat and manage a variety of endocrine disorders such as obesity, diabetes, non- alcoholic fatty liver disease and metabolic syndrome. The precise mechanisms by which probiotics exert their beneficial effects on endocrine disorders and its associated problems are still indecisive. It seems that regulating the immune system and suppressing pro-inflammatory pathways like tumor necrosis factor-α and interleukin-6 or triggering anti-inflammatory pathways like interleukin-4 and 10 may be one of the potential mechanisms in the managing of endocrine disorders. In this systematic review, we hypothesized that various probiotic strains (Lactobacillus, Biofidiobacteria, Streptococcus, Entrococcus, Clostridium, and Bacillus) alone or in combination with each other could manage endocrine disorders via modulating inflammatory pathways such as suppressing pro-inflammatory cytokines (IL-6, IL-12, TNF-α, TNF-β, NFκB, and MCP-1), stimulating anti-inflammatory cytokines (IL-4,IL-6, IL-22, IL-23, IL-33, and TGF-β) and maintaining other factors like C-reactive protein, Toll like receptors, LPS, and NK cells. Data source this search was performed in PubMed and Scopus. Both human and animal studies were included. Among more than 15,000 papers, 25 studies were identified as eligible for more assessments. Quality assessment of the studies was cheeked by two researchers independently by title and abstract screening, then article which have inclusion criteria were included, and data retrieved from the included full text studies as the authors had originally reported. Results specified that Lactobacillus has been the most widely used probiotic as well as which one exhibiting the extend of the therapeutic effects on endocrine disorders, especially obesity by modulating immune responses. Also, most studies have revealed that probiotics through suppressing pro-inflammatory pathways specially via reducing levels TNF-α cytokine exhibited protective or beneficial effects on endocrine diseases particularly obesity as well as through decreasing level of IL-6 induced therapeutic effects in diabetes. This systematic review suggests that probiotics could ameliorate endocrine disorders via their immunomodulatory effects.

Navigating nonalcoholic fatty liver disease (NAFLD): Exploring the roles of estrogens, pharmacological and medical interventions, and life style

The pursuit of studying this subject is driven by the urgency to address the increasing global prevalence of Non-Alcoholic Fatty Liver Disease (NAFLD) and its profound health implications. NAFLD represents a significant public health concern due to its association with metabolic disorders, cardiovascular complications, and the potential progression to more severe conditions like non-alcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. Liver estrogen signaling is important for maintaining liver function, and loss of estrogens increases the likelihood of NAFLD in postmenopausal women. Understanding the multifaceted mechanisms underlying NAFLD pathogenesis, its varied treatment strategies, and their effectiveness is crucial for devising comprehensive and targeted interventions. By unraveling the intricate interplay between genetics, lifestyle, hormonal regulation, and gut microbiota, we can unlock insights into risk stratification, early detection, and personalized therapeutic approaches. Furthermore, investigating the emerging pharmaceutical interventions and dietary modifications offers the potential to revolutionize disease management. This review reinforces the role of collaboration in refining NAFLD comprehension, unveiling novel therapeutic pathways, and ultimately improving patient outcomes for this intricate hepatic condition.

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.

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 Gut Microbiome and Ferroptosis in MAFLD

Metabolic-associated fatty liver disease (MAFLD) is a new disease definition, and is proposed to replace the previous name, nonalcoholic fatty liver disease (NAFLD). Globally, MAFLD/NAFLD is the most common liver disease, with an incidence rate ranging from 6% to 35% in adult populations. The pathogenesis of MAFLD/NAFLD is closely related to insulin resistance (IR), and the genetic susceptibility to acquired metabolic stress-associated liver injury. Similarly, the gut microbiota in MAFLD/NAFLD is being revaluated by scientists, as the gut and liver influence each other via the gut-liver axis. Ferroptosis is a novel form of programmed cell death caused by iron-dependent lipid peroxidation. Emerging evidence suggests that ferroptosis has a key role in the pathological progression of MAFLD/NAFLD, and inhibition of ferroptosis may become a novel therapeutic strategy for the treatment of NAFLD. This review focuses on the main mechanisms behind the promotion of MAFLD/NAFLD occurrence and development by the intestinal microbiota and ferroptosis. It outlines new strategies to target the intestinal microbiota and ferroptosis to facilitate future MAFLD/NAFLD therapies.

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.

Gut microbiota therapy for nonalcoholic fatty liver disease: Evidence from randomized clinical trials

Nonalcoholic fatty liver disease (NAFLD) has a high prevalence worldwide, but there are no medications approved for treatment. Gut microbiota would be a novel and promising therapeutic target based on the concept of the gut-liver axis in liver disease. We reviewed randomized controlled trials on gut microbiota therapy in NAFLD in this study to evaluate its efficacy and plausibility in NAFLD.

Oral 24-week probiotics supplementation did not decrease cardiovascular risk markers in patients with biopsy proven NASH: A double-blind placebo-controlled randomized study

INTRODUCTION AND OBJECTIVES

Cardiovascular disease (CVD) is the major cause of death in non-alcoholic fatty liver disease (NAFLD), a clinical condition without any approved pharmacological therapy. Probiotics are often indicated for the disease, but their results are controversial in part due to the poor quality of studies. Thus, we investigated the impact of 24-week probiotics supplementation on cardiovascular risk (CVR) in biopsy-proven non-alcoholic steatohepatitis (NASH) patients.

PATIENTS AND METHODS

Double-blind, placebo-controlled, single-center study (NCT03467282), adult NASH, randomized for 24 weeks daily sachets of probiotic mix (10⁹CFU of Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus paracasei and Bifidobacterium lactis) or placebo. Clinical scores (atherogenic indexes, atherosclerotic cardiovascular disease-ASCVD and systematic coronary risk evaluation-SCORE), biochemistry, miR-122, miR-33a, plasminogen activator inhibitor-1 (PAI-1), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), were determined before and after the intervention.

RESULTS

Forty-six patients were enrolled (23 received probiotics and 23 placebo), with a mean age of 51.7 years, most of them females and whites. Clinical and demographic features were similar between the groups at the baseline. The Median NAFLD activity score was 4.13 in both groups. Fibrosis was mild in most patients (15.2% and 65.2% F0 and F1, respectively). Treatment did not promote any clinically significant changes in body mass index or laboratory, including lipid and glucose profile. High CVR patients through atherogenic indexes decreased from baseline in both groups, as well as PAI-1 and miR-122 levels, although there was no difference between probiotics and placebo.

CONCLUSIONS

A 24-week probiotic mix administration was not superior to placebo in reducing CVR markers in patients with NASH.

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.

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.

Age-Related NAFLD: The Use of Probiotics as a Supportive Therapeutic Intervention

Human aging, a natural process characterized by structural and physiological changes, leads to alterations of homeostatic mechanisms, decline of biological functions, and subsequently, the organism becomes vulnerable to external stress or damage. In fact, the elderly population is prone to develop diseases due to deterioration of physiological and biological systems. With aging, the production of reactive oxygen species (ROS) increases, and this causes lipid, protein, and DNA damage, leading to cellular dysfunction and altered cellular processes. Indeed, oxidative stress plays a key role in the pathogenesis of several chronic disorders, including hepatic diseases, such as non-alcoholic fatty liver disease (NAFLD). NAFLD, the most common liver disorder in the Western world, is characterized by intrahepatic lipid accumulation; is highly prevalent in the aging population; and is closely associated with obesity, insulin resistance, hypertension, and dyslipidemia. Among the risk factors involved in the pathogenesis of NAFLD, the dysbiotic gut microbiota plays an essential role, leading to low-grade chronic inflammation, oxidative stress, and production of various toxic metabolites. The intestinal microbiota is a dynamic ecosystem of microbes involved in the maintenance of physiological homeostasis; the alteration of its composition and function, during aging, is implicated in different liver diseases. Therefore, gut microbiota restoration might be a complementary approach for treating NAFLD. The administration of probiotics, which can relieve oxidative stress and elicit several anti-aging properties, could be a strategy to modify the composition and restore a healthy gut microbiota. Indeed, probiotics could represent a valid supplement to prevent and/or help treating some diseases, such as NAFLD, thus improving the already available pharmacological intervention. Moreover, in aging, intervention of prebiotics and fecal microbiota transplantation, as well as probiotics, will provide novel therapeutic approaches. However, the relevant research is limited, and several scientific research works need to be done in the near future to confirm their efficacy.

The contribution of the gut-liver axis to the immune signaling pathway of NAFLD

Nonalcoholic fatty liver disease (NAFLD) is the liver manifestation of metabolic syndrome and is the most common chronic liver disease in the world. The pathogenesis of NAFLD has not been fully clarified; it involves metabolic disturbances, inflammation, oxidative stress, and various forms of cell death. The “intestinal-liver axis” theory, developed in recent years, holds that there is a certain relationship between liver disease and the intestinal tract, and changes in intestinal flora are closely involved in the development of NAFLD. Many studies have found that the intestinal flora regulates the pathogenesis of NAFLD by affecting energy metabolism, inducing endotoxemia, producing endogenous ethanol, and regulating bile acid and choline metabolism. In this review, we highlighted the updated discoveries in intestinal flora dysregulation and their link to the pathogenesis mechanism of NAFLD and summarized potential treatments of NAFLD related to the gut microbiome.

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.

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.

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].

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.

Advancements in the treatment of non-alcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is a series of diseases, involving excessive lipid deposition in the liver and is often accompanied by obesity, diabetes, dyslipidemia, abnormal blood pressure, and other metabolic disorders. In order to more accurately reflect its pathogenesis, an international consensus renamed NAFLD in 2020 as metabolic (dysfunction) associated with fatty liver disease (MAFLD). The changes in diet and lifestyle are recognized the non-drug treatment strategies; however, due to the complex pathogenesis of NAFLD, the current drug therapies are mainly focused on its pathogenic factors, key links of pathogenesis, and related metabolic disorders as targets. There is still a lack of specific drugs. In clinical studies, the common NAFLD treatments include the regulation of glucose and lipid metabolism to protect the liver and anti-inflammation. The NAFLD treatments based on the enterohepatic axis, targeting gut microbiota, are gradually emerging, and various new metabolism-regulating drugs are also under clinical development. Therefore, this review article has comprehensively discussed the research advancements in NAFLD treatment in recent years.

Gut Microbiome-Mediated Alteration of Immunity, Inflammation, and Metabolism Involved in the Regulation of Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is one of the leading causes of end-stage liver disease, leading to a rapidly growing global public health burden. The term “gut microbiome (GM)” refers to the approximately 100 trillion microbial cells that inhabit the host’s gastrointestinal tract. There is increasing evidence that GM is involved in the pathogenesis of NAFLD and may be a potential target for intervention. To explore GM-based strategies for precise diagnosis and treatment of NAFLD, great efforts have been made to develop a comprehensive and in-depth understanding of the host–microbe interaction. This review evaluates this interaction critically, mainly considering the intricate regulation of the metabolism, immunity, and inflammatory status during the evolution of the disease pathogenesis, revealing roles for the GM in NAFLD by examining advances in potential mechanisms, diagnostics, and modulation strategies.

Synopsis: Considering the intricate metabolic and immune/inflammatory homeostasis regulation, we evaluate the latest understanding of the host–microbe interaction and reveal roles for the gastrointestinal microbiome in NAFLD. Strategies targeting the gastrointestinal microbiome for the diagnosis and treatment of NAFLD are proposed.

Lipid Disorders in NAFLD and Chronic Kidney Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver dysfunction and is characterized by exaggerated lipid accumulation, inflammation and even fibrosis. It has been shown that NAFLD increases the risk of other chronic diseases, particularly chronic kidney disease (CKD). Lipid in excess could lead to liver and kidney lesions and even end-stage disease through diverse pathways. Dysregulation of lipid uptake, oxidation or de novo lipogenesis contributes to the toxic effects of ectopic lipids which promotes the development and progression of NAFLD and CKD via triggering oxidative stress, apoptosis, pro-inflammatory and profibrotic responses. Importantly, dyslipidemia and release of pro-inflammatory cytokines caused by NAFLD (specifically, nonalcoholic steatohepatitis) are considered to play important roles in the pathological progression of CKD. Growing evidence of similarities between the pathogenic mechanisms of NAFLD and those of CKD has attracted attention and urged researchers to discover their common therapeutic targets. Here, we summarize the current understanding of molecular aberrations underlying the lipid metabolism of NAFLD and CKD and clinical evidence that suggests the relevance of these pathways in humans. This review also highlights the orchestrated inter-organ cross-talk in lipid disorders, as well as therapeutic options and opportunities to counteract NAFLD and CKD.

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).

Accomplishment of probiotics in human health pertaining to immunoregulation and disease control

It is a well-established fact that the microbiome harboring the human body plays a critical role in maintaining human health and can influence treatments against various ailments. Human microbiome-based research contemplates the possibility of selecting and administering specific commensal bacterial strains to modulate the gut microbiota to attain favorable outcomes to the therapies. Consumption of probiotics and probiotic-based dietary supplements as functional foods has been a promising treatment strategy against various diseases. Clinical studies demonstrate that probiotic administration alters gut microbiota composition and instigates immune modulation in the host. The benefits of probiotics are reported to be strain-specific and depend on the host's baseline immune competence. This review explores the role of probiotics in alleviating symptoms of allergy, cancer, cardio vascular (CV) diseases, diabetes mellitus (DM), bowel diseases (IBD and IBS), periodontal disease, diseases affecting liver and kidney, neuroinflammatory diseases, and viral infections. Also, it surveyed the broad spectrum bioactive compounds produced by probiotics and possible mechanisms that trigger the immune system.

Nonalcoholic Fatty Liver Disease (NAFLD) as Model of Gut-Liver Axis Interaction: From Pathophysiology to Potential Target of Treatment for Personalized Therapy

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of liver disease worldwide, affecting both adults and children and will result, in the near future, as the leading cause of end-stage liver disease. Indeed, its prevalence is rapidly increasing, and NAFLD is becoming a major public health concern. For this reason, great efforts are needed to identify its pathogenetic factors and new therapeutic approaches. In the past decade, enormous advances understanding the gut-liver axis-the complex network of cross-talking between the gut, microbiome and liver through the portal circulation-have elucidated its role as one of the main actors in the pathogenesis of NAFLD. Indeed, evidence shows that gut microbiota is involved in the development and progression of liver steatosis, inflammation and fibrosis seen in the context of NAFLD, as well as in the process of hepatocarcinogenesis. As a result, gut microbiota is currently emerging as a non-invasive biomarker for the diagnosis of disease and for the assessment of its severity. Additionally, to its enormous diagnostic potential, gut microbiota is currently studied as a therapeutic target in NAFLD: several different approaches targeting the gut homeostasis such as antibiotics, prebiotics, probiotics, symbiotics, adsorbents, bariatric surgery and fecal microbiota transplantation are emerging as promising therapeutic options.

Effects of Probiotics on Human Health and Disease: A Review

Alteration of the gut microbiome in order to achieve a balance in the normal flora of the intestine could be very beneficial in maintaining the health of the human. Probiotics are living microbial supplements that are added to the diet and have beneficial effects on the host by improving the balance of the intestinal microflora. The purpose of this study is to review previous studies on the effects of probiotics on human health and various diseases. The Farsi and English electronic databases such as, SID, Iranmedex, Magiran, Google Scholar, PubMed and ISI Web of Knowledge were searched and the published articles that have studied the effects of probiotics on the prevention and treatment of various diseases were included in the study. The review of published articles related to the subject showed that consumption of probiotics, prebiotics and proper diet have the significant effects on the health of the digestive system and has reduced and improved symptoms of different disorders and diseases. Further research is needed to better understand the underlying mechanisms of probiotic function and confirm the role of the probiotics in preventing and treating various types of cancers and other diseases.

Probiotics alleviate adipose inflammation in high-fat diet-induced obesity by restoring adipose invariant natural killer T cells

OBJECTIVE

Invariant natural killer T (iNKT) cells, which are depleted in obese individuals, play important roles in preventing diet-induced obesity and associated disorders. Probiotic supplementation can alter the gut microbiota and immunomodulation in obesity. However, it remains unclear whether probiotics can affect visceral adipose iNKT cells. The aim of this study was to analyze the effects of probiotics on adipose iNKT cells in mice with high-fat diet (HFD)-induced obesity and to assess the immunomodulatory function of probiotics and their role in obesity, glucose tolerance, lipid metabolism, insulin resistance, and adipose inflammation.

METHODS

Wildtype (WT) male C57BL/6 mice and CD1d knockout mice were fed an HFD or a normal-fat diet. Some mice received active or heat-sacrificed VSL#3 probiotics. Preventative VSL#3 therapy was also administered to HFD mice. Body weight, metabolic parameters, expression of genes encoding adipose inflammatory factors (interleukin [IL]-4, IL-10, tumor necrosis factor-α, interferon-γ, and IL-6), adipose iNKT cell frequency, and subphenotype were evaluated.

RESULTS

HFD induced more severe obesity in CD1dKO mice than in WT mice. VSL#3 intervention significantly improved HFD-induced weight gain, adipose iNKT cell depletion, and metabolic and adipose inflammatory profiles in WT mice, but not in CD1dKO mice. Preventative VSL#3 treatment improved HFD-induced obesity and metabolic parameters, and elevated total adipose iNKT and IL-4⁺ iNKT cell frequencies.

CONCLUSIONS

Probiotic intervention alleviated weight gain, improved metabolic parameters, and reduced adipose inflammation in HFD-induced obesity. These effects seem to depend on the restoration of visceral adipose iNKT cells. These findings have potential implications for the management of obesity-related diseases.

Effects of therapeutic probiotics on modulation of microRNAs

Probiotics are beneficial bacteria that exist within the human gut, and which are also present in different food products and supplements. They have been investigated for some decades, due to their potential beneficial impact on human health. Probiotics compete with pathogenic microorganisms for adhesion sites within the gut, to antagonize them or to regulate the host immune response resulting in preventive and therapeutic effects. Therefore, dysbiosis, defined as an impairment in the gut microbiota, could play a role in various pathological conditions, such as lactose intolerance, gastrointestinal and urogenital infections, various cancers, cystic fibrosis, allergies, inflammatory bowel disease, and can also be caused by antibiotic side effects. MicroRNAs (miRNAs) are short non-coding RNAs that can regulate gene expression in a post-transcriptional manner. miRNAs are biochemical biomarkers that play an important role in almost all cellular signaling pathways in many healthy and disease states. For the first time, the present review summarizes current evidence suggesting that the beneficial properties of probiotics could be explained based on the pivotal role of miRNAs. Video Abstract.

Microbial Metabolites: Critical Regulators in NAFLD

Non-alcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease throughout the world. The relationship between gut microbiota and NAFLD has been extensively investigated. The gut microbiota is involved in the regulation of NAFLD by participating in the fermentation of indigestible food, interacting with the intestinal mucosal immune system, and influencing the intestinal barrier function, leading to signaling alteration. Meanwhile, the microbial metabolites not only affect the signal transduction pathway in the gut but also reach the liver far away from gut. In this review, we focus on the effects of certain key microbial metabolites such as short-chain fatty acids, trimethylamine-N-oxide, bile acids, and endogenous ethanol and indole in NAFLD, and also summarize several potential therapies targeting the gut-liver axis and modulation of gut microbiota metabolites including antibiotics, prebiotics, probiotics, bile acid regulation, and fecal microbiota transplantation. Understanding the complex interactions between microbial metabolites and NAFLD may provide crucial insight into the pathogenesis and treatment of NAFLD.

Nonalcoholic fatty liver disease and colorectal cancer: Correlation and missing links

Nonalcoholic fatty liver disease (NAFLD) is one of the major metabolic diseases that occur in almost one in every four global population, while colorectal cancer (CRC) is one of the leading causes of cancer related deaths in the world. Individuals with pre-existing NAFLD show a higher rate of developing CRC and liver metastasis, suggesting a causal relationship. Interestingly, both of these diseases are strongly associated with obesity, which is also a growing global health concern. In this current review, we will explore scientific findings that demonstrate the relationship between NAFLD, CRC and obesity, as well as the underlying mechanisms. We will also indicate the missing links and knowledge gaps that require more in-depth investigation.

Effects of synbiotic supplementation on the components of metabolic syndrome in military personnel: a double-blind randomised controlled trial

Introduction

Metabolic syndrome comprises a set of risk factors for chronic diseases including abdominal obesity, increased fasting blood glucose (FBG), altered lipid profile and elevated blood pressure (BP). Due to high prevalence of metabolic syndrome and its complications in the military personnel, the relevant problems should be identified and controlled. Therefore, the present study was conducted to determine the effect of synbiotic supplements on the components of metabolic syndrome in the military personnel with metabolic syndrome.

Methodology

Sixty military personnel with metabolic syndrome were included in this double-blind randomised controlled clinical trial. During the intervention, they were asked to consume one capsule of synbiotic supplement or placebo per day for 8 weeks. Body Mass Index (BMI), waist circumference, BP, FBG and lipid profile were measured before and after the intervention.

Results

The results of the study showed that the synbiotic supplementation had a large significant adjusted effect on the BMI (Cohen’s d=0.82 (95% CI 0.29 to 1.34)). It also had a medium significant adjusted effect on the FBG (Cohen’s d=0.52 (95% CI 0.004 to 1.03)) as well as triglyceride (Cohen’s d=0.65 (95% CI 0.13 to 1.17)).

Conclusion

Findings of the study revealed that synbiotic supplementation may lead to a significant improvement in the BMI, triglyceride and FBG levels in the military personnel. Thus, consumption of synbiotic supplements is recommended as an adjuvant therapy in the military personnel with metabolic syndrome.

Effects of prebiotic dietary fibers and probiotics on human health: With special focus on recent advancement in their encapsulated formulations

Background

Dietary fibers (DFs) are known as potential formulations in human health due to their beneficial effects in control of life-threatening chronic diseases including cardiovascular disease (CVD), diabetes mellitus, obesity and cancer. In recent decades scientists around the globe have shown tremendous interest to evaluate the interplay between DFs and gastrointestinal (GIT) microbiota. Evidences from various epidemiological and clinical trials have revealed that DFs modulate formation and metabolic activities of the microbial communities residing in the human GIT which in turn play significant roles in maintaining health and well-being. Furthermore, interestingly, a rapidly growing literature indicates success of DFs being prebiotics in immunomodulation, namely the stimulation of innate, cellular and humoral immune response, which could also be linked with their significant roles in modulation of the probiotics (live beneficial microorganisms).

Scope and approach

The main focus of the current review is to expressively highlight the importance of DFs being prebiotics in human health in association with their influence on gut microbiota. Now in order to significantly achieve the promising health benefits from these prebiotics, it is aimed to develop novel formulations to enhance and scale up their efficacy. Therefore, finally, herein unlike previously published articles, we highlighted different kinds of prebiotic and probiotic formulations which are being regarded as hot research topics among the scientific community now a days.

Conclusion

The information in this article will specifically provide a platform for the development of novel functional foods the demands for which has risen drastically in recent years.

Gut metabolites and inflammation factors in non-alcoholic fatty liver disease: A systematic review and meta-analysis

The interaction of gut microbiota, related metabolites and inflammation factors with nonalcoholic fatty liver disease (NAFLD) remains unclearly defined. The aim of this systematic review and meta-analysis was to synthesize previous study findings to better understand this interaction. Relevant research articles published not later than September, 2019 were searched in the following databases: Web of Science, PubMed, Embase, and Cochrane Library. The search strategy and inclusion criteria for this study yielded a total of 47 studies, of which only 11 were eligible for meta-analysis. The narrative analysis of these articles found that there is interplay between the key gut microbiota, related metabolites and inflammation factors, which modulate the development and progression of NAFLD. In addition, the results of meta-analysis showed that probiotic supplementation significantly decreased tumor necrosis factor-α (TNF-α) in NAFLD patients (standardized mean difference (SMD) = −0.52, confidence interval (CI): −0.86 to −0.18, and p = 0.003) and C-reactive protein (CRP) (SMD = −0.62, CI: −0.80 to −0.43, and p < 0.001). However, whether therapies can target TNF-α and CRP in order treat NAFLD still needs further investigation. Therefore, these results suggest that the interaction of the key gut microbiota, related metabolites and inflammation factors with NAFLD may provide a novel therapeutic target for the clinical and pharmacological treatment of NAFLD.

Challenges and opportunities in drug development for nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are considered major global medical burdens with high prevalence and steeply rising incidence. Despite the characterization of numerous pathophysiologic pathways leading to metabolic disorder, lipid accumulation, inflammation, fibrosis, and ultimately end-stage liver disease or liver cancer formation, so far no causal pharmacological therapy is available. Drug development for NAFLD and NASH is limited by long disease duration and slow progression and the need for sequential biopsies to monitor the disease stage. Additional non-invasive biomarkers could therefore improve design and feasibility of such. Here, the current concepts on preclinical models, biomarkers and clinical endpoints and trial designs are briefly reviewed.

The Impacts of Synbiotic Supplementation on Periodontal Indices and Biomarkers of Oxidative Stress in Type 2 Diabetes Mellitus Patients with Chronic Periodontitis Under Non-Surgical Periodontal Therapy. A Double-Blind, Placebo-Controlled Trial

AIM

The aim of the current study was to investigate that combination of the synbiotic supplementation in adjunct with non-surgical periodontal therapy (NSPT) is useful in treating periodontitis and biomarkers of oxidative stress in type 2 diabetes mellitus (T2DM) patients.

METHODS

In this study, 47 patients suffering from DM and CP were recruited and randomly assigned to two groups. The intervention (n= 23) and control (n=24) groups received either multispecies probiotic supplement plus 100 mg fructo-oligosaccharide (500 mg in each capsule) or placebo capsule containing 500 mg wheat flour, respectively, every day for 8 weeks. All subjects were treated with NSPT during the intervention period. Serum levels of interleukin-1β (IL-1β), malondialdehyde (MDA), total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and periodontal indices including clinical attachment loss (CAL), pocket depth (PD) (main outcome), BOP, and plaque index were measured before and after the intervention.

RESULTS

Supplementation with the synbiotic with NSPT led to a significant decrease in the levels of IL-1β, MDA, plaque index, PD, and CAL in the intervention group post-intervention (p < 0.05). The serum levels of TAC, SOD, and GPx were significantly increased in the intervention group compared with the baseline (p < 0.05). Consumption of synbiotic with NSPT, compared to the control, resulted in a significant decrease in the mean changes of IL-1β, MDA, and CAL (p < 0.05). Also, the mean changes of TAC and GPx were significantly higher in the intervention group compared with the control group (p < 0.05). Also, in the intervention group was seen a significant reduction in plaque index (p = 0.035) and BOP (p = 0.04) compared with the control group.

CONCLUSION

It was observed that synbiotic supplementation with NSPT may be beneficial in improving inflammatory, antioxidant, and periodontal status in T2DM patients with CP.

Non-alcoholic fatty liver diseases: from role of gut microbiota to microbial-based therapies

Non-alcoholic fatty liver disease (NAFLD) is the well-known disease of the liver in adults and children throughout the world. The main manifestations related to NAFLD are an unusual storage of lipid in hepatocytes (hepatic steatosis) and progression of inflammation for non-alcoholic steatohepatitis (NASH). NAFLD is described as a multifactorial complication due to the genetic predisposition, metabolic functions, inflammatory, gut microbiota (GM), and environmental factors. The GM dysregulation among these factors is correlated to NAFLD development. In recent decades, advanced microbial profiling methods are continuing to shed light on the nature of the changes in the GM caused by NASH and NAFLD. In the current review, we aim to perform a literature review in different library databases and electronic searches (Science Direct, PubMed, and Google Scholar) which were randomly obtained. This will be done in order to provide an overview of the relation between GM and NAFLD, and the role of prebiotics, probiotics, and fecal microbiota transplantation (FMT), as potential therapeutic challenges for NAFLD.

Systematic Review with Meta-Analysis: The Effects of Probiotics in Nonalcoholic Fatty Liver Disease

Background and Aims

Probiotics was considered as a potential therapy for nonalcoholic fatty liver disease (NAFLD) without approval and comprehensive assessment in recent years, which call for a meta-analysis.

Methods

We performed electronic and manual searches including English and Chinese databases published before April 2019, with the use of mesh term and free text of "nonalcoholic fatty liver disease" and "probiotics." Clinical trials evaluating the efficacy of probiotic therapy in NAFLD patients were included according to the eligibility criteria. With the use of random effects models, clinical outcomes were presented as weighted mean difference (WMD) with 95% confidence interval (CI), while heterogeneity and meta-regression were also assessed.

Results

28 clinical trials enrolling 1555 criterion proven NAFLD patients with the use of probiotics from 4 to 28 weeks were included. Overall, probiotic therapy had beneficial effects on body mass index (WMD: -1.46, 95% CI: [-2.44, -0.48]), alanine aminotransferase (WMD: -13.40, 95% CI: [-17.03, -9.77]), aspartate transaminase (WMD: -13.54, 95% CI: [-17.86, -9.22]), gamma-glutamyl transpeptidase (WMD: -9.88, 95% CI: [-17.77, -1.99]), insulin (WMD: -1.32, 95% CI: [-2.43, -0.21]), homeostasis model assessment-insulin resistance (WMD: -0.42, 95% CI: [-0.73, -0.12]), and total cholesterol (WMD: -15.38, 95% CI: [-26.50, -4.25]), but not in fasting blood sugar, lipid profiles, or tumor necrosis factor-alpha.

Conclusion

The systematic review and meta-analysis support that probiotics are superior to placebo in NAFLD patients and could be utilized as a common complementary therapeutic approach.

Role of Probiotics in Non-alcoholic Fatty Liver Disease: Does Gut Microbiota Matter?

Non-alcoholic fatty liver disease (NAFLD) is the hepatic consequence of metabolic syndrome, which often also includes obesity, diabetes, and dyslipidemia. The connection between gut microbiota (GM) and NAFLD has attracted significant attention in recent years. Data has shown that GM affects hepatic lipid metabolism and influences the balance between pro/anti-inflammatory effectors in the liver. Although studies reveal the association between GM dysbiosis and NAFLD, decoding the mechanisms of gut dysbiosis resulting in NAFLD remains challenging. The potential pathophysiology that links GM dysbiosis to NAFLD can be summarized as: (1) disrupting the balance between energy harvest and expenditure, (2) promoting hepatic inflammation (impairing intestinal integrity, facilitating endotoxemia, and initiating inflammatory cascades with cytokines releasing), and (3) altered biochemistry metabolism and GM-related metabolites (i.e., bile acid, short-chain fatty acids, aromatic amino acid derivatives, branched-chain amino acids, choline, ethanol). Due to the hypothesis that probiotics/synbiotics could normalize GM and reverse dysbiosis, there have been efforts to investigate the therapeutic effect of probiotics/synbiotics in patients with NAFLD. Recent randomized clinical trials suggest that probiotics/synbiotics could improve transaminases, hepatic steatosis, and reduce hepatic inflammation. Despite these promising results, future studies are necessary to understand the full role GM plays in NAFLD development and progression. Additionally, further data is needed to unravel probiotics/synbiotics efficacy, safety, and sustainability as a novel pharmacologic approaches to NAFLD.

Effects of probiotics on nonalcoholic fatty liver disease: a systematic review and meta-analysis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) has become prevalent in recent decades, especially in developed countries, and approaches for the prevention and treatment of NAFLD are not clear. The aim of this research was to analyze and summarize randomized controlled trials that investigated the effects of probiotics on NAFLD.

METHODS

Seven databases (PubMed, Embase, the Web of Science, the Cochrane Library, China National Knowledge Infrastructure, Wan Fang Data, and VIP Database) were searched. Then, eligible studies were identified. Finally, proper data extraction, synthesis and analysis were performed by trained researchers.

RESULTS

Anthropometric parameters: with use of probiotics weight was reduced by 2.31 kg, and body mass index (BMI) was reduced by 1.08 kg/m². Liver function: probiotic treatment reduced the alanine aminotransferase level by 7.22 U/l, the aspartate aminotransferase level by 7.22 U/l, the alkaline phosphatase level by 25.87 U/l, and the glutamyl transpeptidase level by -5.76 U/l. Lipid profiles: total cholesterol, low-density lipoprotein cholesterol, and triglycerides were significantly decreased after probiotic treatment. Their overall effects (shown as standard mean difference) were -0.73, -0.54, and -0.36, respectively. Plasma glucose: probiotics reduced the plasma glucose level by 4.45 mg/dl and the insulin level by 0.63. Cytokines: probiotic treatment decreased tumor necrosis factor alpha by 0.62 and leptin by 1.14. Degree of liver fat infiltration (DFI): the related risk of probiotics for restoring DFI was 2.47 (95% confidence interval, 1.61-3.81, p < 0.001).

CONCLUSION

Probiotic treatment or supplementation is a promising therapeutic method for NAFLD.

Effects of probiotic supplementation on the regulation of blood lipid levels in overweight or obese subjects: a meta-analysis

BACKGROUND

Obesity is a risk factor for many deadly diseases. Meanwhile, the prevalence of obesity has been continuously increasing in many countries. Probiotics are defined as live microorganisms that confer health benefits on hosts. Probiotic supplementation could reduce body weight, body mass index (BMI) and fat percentage. However, it is unclear whether supplementation with probiotics is beneficial to lower blood lipid levels for obese or overweight people.

METHODS

In this study, a comprehensive search across multiple databases was performed to identify studies that focused on the effects of probiotics on blood lipid levels in overweight or obese subjects. The meta-analysis included studies that compared the variations in blood lipid (total cholesterol (TC), low density lipoprotein (LDL), high density lipoprotein (HDL) and triglyceride (TG)) concentrations between overweight and obese subjects who were supplemented with probiotics versus the controls who were not supplemented with probiotics.

RESULTS

Our findings indicated that probiotic supplementation in obese or overweight people was associated with significantly larger reductions in TC and LDL levels compared to a lack of probiotic supplementation in the control subjects. However, there was no significant difference in the variations between HDL and TG concentrations.

CONCLUSION

Probiotic supplementation reduced TC and LDL concentrations in obese or overweight people. Additional data from large clinical trials are required to confirm the efficacy and safety of probiotics in the regulation of blood lipid levels in obese or overweight people.

Combined Amelioration of Ginsenoside (Rg1, Rb1, and Rg3)-enriched Korean Red Ginseng and Probiotic Lactobacillus on Non-alcoholic Fatty Liver Disease

BACKGROUND

Red ginseng is a traditional medicine that has been used to treat numerous metabolic and inflammatory diseases. Probiotic administration has been established to have beneficial effects in non-alcoholic fatty liver disease (NAFLD). The purpose of this study was to determine whether a combination of Korean red ginseng (KRG) and probiotics could synergistically reduce NAFLD and liver inflammation compared with the effects reported for each individual product.

METHOD

db/db and C57BL/6 mice were fed a normal chow diet and high-fat diet (HFD), respectively, and were treated with KRG, probiotics, or both. Samples were examined for lipid content, kinase protein phosphorylation, and gene expression patterns.

RESULTS

KRG- and probiotic-treated HFD-fed mice exhibited a reduction in body weight and a decrease in inflammatory cytokine secretion compared with the non-treated control mice. The same treatment was less successful in improving NAFLD parameters in the db/db mice while the combination of both products did not enhance their therapeutic potential.

CONCLUSION

The results of this study indicate that KRG and probiotics administration ameliorated NAFLD symptoms in a mouse model of dyslipidemia by reducing weight gain and liver inflammation. Coadministration of both products did not enhance their efficacy, and further research should be conducted to clarify their mechanisms of action.