Gut--liver axis: the impact of gut microbiota on non alcoholic fatty liver disease

What are the main areas of focus to prevent or treat non-alcoholic fatty liver disease?

Recently, a growing body of information has accumulated to suggest that nutritional status and food compounds impact on the development or progression of non-alcoholic fatty liver disease (NAFLD). The best strategy to prevent and treat NAFLD is to modify diet and lifestyle by maintaining a healthy weight, following a well-balanced diet with appropriate energy intake and increasing physical activity or strength training. Here we review the literatures and discuss existing and potential therapeutic strategies for the prevention and management of NAFLD, emphasizing the description of nutritional status and its clinical impact on the outcomes of NAFLD.

The promising role of probiotic and synbiotic therapy in aminotransferase levels and inflammatory markers in patients with nonalcoholic fatty liver disease - a systematic review and meta-analysis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease worldwide. The pathogenesis of NAFLD is complex and multifactorial. There is growing evidence that altered gut microbiota plays a key role in NAFLD progression. Probiotics/synbiotics, by modifying gut microbiota, may be a promising treatment choice for NAFLD management.

AIM

The aim of this study was to study the effect of probiotics/synbiotics on various laboratory and radiographic parameters in NAFLD management.

MATERIALS AND METHODS

A systematic review and meta-analysis were carried out according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. We searched PubMed, Medline, and Google Scholar for randomized-controlled trials that studied the role of probiotics/synbiotics in NAFLD. The primary outcome was change in baseline alanine aminotransferase and aspartate aminotransferase in the treatment arm. We used a random-effects model and inverse variance for the continuous data to estimate the mean difference (MD) and the standard mean difference (SMD) in RevMan Version 5.3.

RESULTS

We included 12 randomized-controlled trials for analysis. The intervention arm, which comprised of the probiotic and/or the synbiotic arm, showed a significant improvement in alanine aminotransferase levels, MD=-13.93, confidence interval (CI)=-20.20 to -7.66, P value of less than 0.0001, I=92% and aspartate aminotransferase levels MD=-11.45, CI=-15.15 to -7.74, P value of less than 0.00001, I=91%. There was a reduction in high-sensitivity C-reactive protein levels in the intervention arm, SMD=-0.68, CI=-1.10 to -0.26, P value of 0.001, I=0%. The liver fibrosis score improved in the intervention arm, MD=-0.71, CI=-0.81 to -0.61, P value less than 0.00001, I=0%.

CONCLUSION

Probiotic/synbiotic use improves aminotransaminase levels and reduces proinflammatory marker high-sensitivity C-reactive protein and liver fibrosis in NAFLD patients.

Bacillus amyloliquefaciens SC06 Protects Mice Against High-Fat Diet-Induced Obesity and Liver Injury via Regulating Host Metabolism and Gut Microbiota

Obesity and the related liver diseases are prevalent around the world. Although probiotics have been shown to prevent obesity through multiple ways, only few researches investigated the lipid-lowering effects of probiotic Bacillus. Moreover, the limited results consistently suggested that Bacillus regulated genes related to lipogenesis and oxidation, but no further exploration was made. Our previous study revealed that Bacillus amyloliquefaciens SC06 has a potent antioxidant capacity in vitro. The aim of this study is to investigate the effects of SC06 on obesity and the associated liver injury of high-fat diet (HFD)-fed-mice and its underlying mechanism. By feeding normal chow (NC), NC+SC06, HFD, and HFD+SC06 to mice, we found that SC06 improved body weight gain, hepatic steatosis, and glucose metabolism of HFD-mice. Furthermore, SC06 also increased the antioxidant capacity of mice through Nrf2/Keap1 signaling pathway. High-throughput sequencing of 16S rRNA gene showed that HFD changed the gut microbiota dramatically, while HFD+SC06 decreased the ratio of Firmicutes/Bacteroidetes and increased TM7 abundance. More differences were also found in lower taxa. Altogether, SC06 is a potential probiotic that decreases HFD-related lipid accumulation and liver injury via regulating the antioxidant capacity and host gut microbiota.

Linderae radix ethanol extract attenuates alcoholic liver injury via attenuating inflammation and regulating gut microbiota in rats

This study aimed to explore the influence of gut microbiota alterations induced by Linderae radix ethanol extract (LREE) on alcoholic liver disease (ALD) in rats and to study the anti-inflammatory effect of LREE on ALD through the lipopolysaccharide (LPS) toll-like receptor 4 (TLR4)-nuclear factor kappa B (NF-κB) pathway. ALD rat models were established by intragastric liquor [50% (v/v) ethanol] administration at 10 mL/kg body weight for 20 days. Rats were divided into six groups: normal group (no treatment), model group (ALD rats), Essentiale group (ALD rats fed with Essentiale, 137 mg/kg), and LREE high/moderate/low dose groups (ALD rats fed with 4, 2, or 1 g LREE/kg). NF-κB and LPS levels were evaluated. Liver pathological changes and intestinal ultrastructure were examined by hematoxylin and eosin staining and transmission electron microscopy. The gut microbiota composition was evaluated by 16S rDNA sequencing. Expression levels of TLR4 and CD68 in liver tissue, and occludin and claudin-1 in intestinal tissue were measured. LREE treatment significantly reduced NF-κB and LPS levels, improved liver pathological changes, and ameliorated intestinal ultrastructure injury. Meanwhile, LREE-fed groups showed a higher abundance of Firmicutes and a lower abundance of Bacteroidetes than the rats in the model group. Administration of LREE suppressed TLR4 overexpression and promoted the expression of occludin and claudin-1 in intestine tissue. Thus, LREE could partly ameliorate microflora dysbiosis, suppress the inflammatory response, and attenuate liver injury in ALD rats. The protective effect of LREE might be related to the LPS-TLR4-NF-κB pathway.

Potential Link between Gut Microbiota and Deoxynivalenol-Induced Feed Refusal in Weaned Piglets

This study investigated the potential link between gut microbiota and deoxynivalenol (DON)-induced feed refusal. A total of 24 barrows were randomly divided into one of three diets containing 0.61 (control diet), 1.28, or 2.89 mg DON/kg feed for 28 days. Dietary exposure to DON at 2.89 mg/kg significantly decreased the relative abundances of unclassified_f_Lachnospiraceae, Phascolarctobacterium and Ruminococcaceae_UCG-014, whereas it increased Prevotella_9 and norank_f_Prevotellaceae in the cecal digesta. Moreover, the decreased relative abundance of unclassified_f_Lachnospiraceae induced by DON exposure was positively correlated with average daily feed intake. Exposure to DON increased the serum concentrations of glucagon-like peptide-1 and peptide YY but reduced the levels of serum growth hormone and insulin-like growth factor 1. In summary, these findings suggest that chronic dietary exposure to DON induces disturbances of intestinal microbiota. Disturbed appetite-regulating hormones and somatotropic-axis-hormone secretion induced by negative microbial changes could be the potential mechanisms for DON-induced anorexia.

The Effects of Vegetarian and Vegan Diets on Gut Microbiota

The difference in gut microbiota composition between individuals following vegan or vegetarian diets and those following omnivorous diets is well documented. A plant-based diet appears to be beneficial for human health by promoting the development of more diverse and stable microbial systems. Additionally, vegans and vegetarians have significantly higher counts of certain Bacteroidetes-related operational taxonomic units compared to omnivores. Fibers (that is, non-digestible carbohydrates, found exclusively in plants) most consistently increase lactic acid bacteria, such as Ruminococcus, E. rectale, and Roseburia, and reduce Clostridium and Enterococcus species. Polyphenols, also abundant in plant foods, increase Bifidobacterium and Lactobacillus, which provide anti-pathogenic and anti-inflammatory effects and cardiovascular protection. High fiber intake also encourages the growth of species that ferment fiber into metabolites as short-chain fatty acids (SCFAs), including acetate, propionate, and butyrate. The positive health effects of SCFAs are myriad, including improved immunity against pathogens, blood-brain barrier integrity, provision of energy substrates, and regulation of critical functions of the intestine. In conclusion, the available literature suggests that a vegetarian/vegan diet is effective in promoting a diverse ecosystem of beneficial bacteria to support both human gut microbiome and overall health. This review will focus on effects of different diets and nutrient contents, particularly plant-based diets, on the gut microbiota composition and production of microbial metabolites affecting the host health.

The Gut Microbiome Signatures Discriminate Healthy From Pulmonary Tuberculosis Patients

Cross talk occurs between the human gut and the lung through a gut-lung axis involving the gut microbiota. However, the signatures of the human gut microbiota after active Mycobacterium tuberculosis infection have not been fully understood. Here, we investigated changes in the gut microbiota in tuberculosis (TB) patients by shotgun sequencing the gut microbiomes of 31 healthy controls and 46 patients. We observed a dramatic changes in gut microbiota in tuberculosis patients as reflected by significant decreases in species number and microbial diversity. The gut microbiota of TB patients were mostly featured by the striking decrease of short-chain fatty acids (SCFAs)-producingbacteria as well as associated metabolic pathways. A classification model based on the abundance of three species, Haemophilus parainfluenzae, Roseburia inulinivorans, and Roseburia hominis, performed well for discriminating between healthy and diseased patients. Additionally, the healthy and diseased states can be distinguished by SNPs in the species of B. vulgatus. We present a comprehensive profile of changes in the microbiota in clinical TB patients. Our findings will shed light on the design of future diagnoses and treatments for M. tuberculosis infections.

The links between the gut microbiome and non-alcoholic fatty liver disease (NAFLD)

NAFLD is currently the main cause of chronic liver disease in developed countries, and the number of NAFLD patients is growing worldwide. NAFLD often has similar symptoms to other metabolic disorders, including type 2 diabetes and obesity. Recently, the role of the gut microbiota in the pathophysiology of many diseases has been revealed. Regarding NAFLD, experiments using gut microbiota transplants to germ-free animal models showed that fatty liver disease development is determined by gut bacteria. Moreover, the perturbation of the composition of the gut microbiota has been observed in patients suffering from NAFLD. Numerous mechanisms relating the gut microbiome to NAFLD have been proposed, including the dysbiosis-induced dysregulation of gut endothelial barrier function that allows for the translocation of bacterial components and leads to hepatic inflammation. In addition, the various metabolites produced by the gut microbiota may impact the liver and thus modulate NAFLD susceptibility. Therefore, the manipulation of the gut microbiome by probiotics, prebiotics or synbiotics was shown to improve liver phenotype in NAFLD patients as well as in rodent models. Hence, further knowledge about the interactions among dysbiosis, environmental factors, and diet and their impacts on the gut-liver axis can improve the treatment of this life-threatening liver disease and its related disorders.

Fatty Liver Disease and Gut Microbiota: A Comprehensive Update

Nonalcoholic fatty liver disease (NAFLD) is the accumulation of fat in the liver in the absence of secondary causes. NAFLD is a multifactorial disease that results from the interaction of genetic predisposition and metabolic, inflammatory and environmental factors. Among these factors, dysregulation of gut microbiome has been linked to the development of fatty liver disease. The microbiome composition can be modified by dietary habits leading to gut microbiome dysbiosis, especially when a diet is rich in saturated fats, animal products and fructose sugars. Different species of bacteria in the gut metabolize nutrients differently, triggering different pathways that contribute to the accumulation of fat within the liver and triggering inflammatory cascades that promote liver damage. In this review, we summarize the current understanding of the roles of gut microbiota in mediating NAFLD development and discuss possible gut microbiota-targeted therapies for NAFLD. We summarize experimental and clinical evidence, and draw conclusions on the therapeutic potential of manipulating gut microbiota to decrease the incidence and prevalence of fatty liver disease.

Intestinal Barrier Function-Non-alcoholic Fatty Liver Disease Interactions and Possible Role of Gut Microbiota

Non-alcoholic fatty liver disease (NAFLD) is a metabolic stress liver injury that is closely related to obesity, insulin resistance, type 2 diabetes, atherosclerosis, and metabolic syndrome. The pathological features are diffuse hepatic vesicular steatosis, including non-alcoholic steatohepatitis, liver fibrosis, and even liver cancer. A variety of pathological outcomes cause serious harm to human health. At present, an increasing number of researchers are investigating the pathogenesis of NAFLD from the perspective of changes in the function of the intestinal barrier. The physical, chemical, immunological, and microbiological barriers in the intestinal tract constitute the complete intestinal barrier, which plays an important defensive role against the invasion of harmful substances from the intestines. Protecting the function of the intestinal barrier is a new way to treat NAFLD and its related diseases. In this perspective, we summarized the current knowledge of the role of the intestinal barrier in NAFLD.

The role of gut microbiota in liver disease development and treatment

Liver cancer is the sixth most common cancer worldwide, and the third most common cause of cancer-related death. Hepatocellular carcinoma (HCC), which accounts for more than 90% of primary liver cancers, is an important public health problem. In addition to cirrhosis caused by hepatitis B viral (HBV) or hepatitis C viral (HCV) infection, non-alcoholic fatty liver disease (NAFLD) is becoming a major risk factor for liver cancer because of the prevalence of obesity. Non-alcoholic steatohepatitis (NASH) will likely become the leading indication for liver transplantation in the future. It is well recognized that gut microbiota is a key environmental factor in the pathogenesis of liver disease and cancer. The interplay between gut microbiota and liver disease has been investigated in animal and clinical studies. In this article, we summarize the roles of gut microbiota in the development of liver disease as well as gut microbiota-targeted therapies.

Sphingosine-1-phosphate signaling and the gut-liver axis in liver diseases

The liver is the central organ involved in lipid metabolism and the gastrointestinal (GI) tract is responsible for nutrient absorption and partitioning. Obesity, dyslipidemia and metabolic disorders are of increasing public health concern worldwide, and novel therapeutics that target both the liver and the GI tract (gut-liver axis) are much needed. In addition to aiding fat digestion, bile acids act as important signaling molecules that regulate lipid, glucose and energy metabolism via activating nuclear receptor, G protein-coupled receptors (GPCRs), Takeda G protein receptor 5 (TGR5) and sphingosine-1-phosphate receptor 2 (S1PR2). Sphingosine-1-phosphate (S1P) is synthesized by two sphingosine kinase isoforms and is a potent signaling molecule that plays a critical role in various diseases such as fatty liver, inflammatory bowel disease (IBD) and colorectal cancer. In this review, we will focus on recent findings related to the role of S1P-mediated signaling pathways in the gut-liver axis.

Gut microbiota: novel therapeutic target for nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the most common and increasing liver diseases worldwide with a prevalence of 20-33%. NAFLD may progress to fibrosis, compensated cirrhosis, advanced cirrhosis, or hepatocellular carcinoma. Despite the increasing prevalence of NAFLD, definitive medical treatment has not been established, with the exception of lifestyle modification with exercise. Because of the direct connection via portal vein between the intestines and the liver (gut-gut microbiota-liver axis), gut microbiota and associated dysbiosis have been known as regulators in the pathophysiology of NAFLD. Area covered: New therapeutic approaches for modulation of gut microbiota have been proposed and the effectiveness of new therapies including probiotics, prebiotics, synbiotics, bile acid regulation, absorbent, and fecal microbiota transplantation have been demonstrated in recent several studies. This review focuses on the available evidences for new therapies modulating gut microbiota in the management and the prevention of NAFLD. Expert commentary: Gut-gut microbiota-liver axis may play an important role in the etiology of many liver diseases, including NAFLD. It is logical to seek the manipulation of this axis, and further studies are required to understand the underlying precise mechanisms of microbiota-modulation on NAFLD.

Clinical, anthropometric, biochemical and histological character of nonalcoholic fatty liver disease without Insulin Resistance

OBJECTIVES

Nonalcoholic Fatty Liver Disease (NAFLD) is thought to be a hepatic manifestation of Metabolic Syndrome (MS) or Insulin Resistance (IR). The aim of the study was to explore the clinical, anthropometric, metabolic, biochemical and histological profile of NAFLD patients without IR by comparing it with NAFLD with IR.

METHODS

Total 851 patients with sonographic evidence of fatty liver were included. These patients underwent clinical, anthropometric, biochemical and histological evaluation. IR was calculated using the homeostatic model assessment. Liver biopsy done in 285 patients who consented for the procedure and who had MS or raised ALT.

RESULTS

Among 851 NAFLD patients, 561(65.9%) patients were without IR and 290 (34.1%) patients were with IR. The proportion of male sex [230 (41.0%) vs. 89 (30.7%); P = 0.046] were higher but diabetes [19.10% vs. 39.0%; P = 0.000] and MS were [58.80%vs. 78.10%; P = 0.014] significantly lower in non IR group. Body Mass Index (BMI) kg/m² and Waist Circumference (WC) in cm were also lower in non IR group: [26.6 ± 3.5 vs. 27.9 ± 4.3; P = 0.002] and [93.3 ± 8.4 vs. 95.9 ± 8.4; P = .003]. Lipid profile, ALT, AST and ALP were not differed between the groups. Histopathology reports revealed that lobular inflammation, ballooning and fibrosis were similar in two groups, only steatosis score was higher in IR group [2.0 ± 0.7 vs. 1.8 ± 0.8; P = 0.007].

CONCLUSION

There are significant proportion of NAFLD patients without IR in Bangladesh. NAFLD patients without IR predominantly male, had lower BMI, WC, MS and diabetes. Histologically NAFLD without IR equally severe with ballooning, lobular inflammation and fibrosis except steatosis. Insulin resistance is the principal but not the sole factor for NAFLD in our population.

Gegen Qinlian Decoction Attenuates High-Fat Diet-Induced Steatohepatitis in Rats via Gut Microbiota

Gut microbiota play an important role in modulating energy contribution, metabolism, and inflammation, and disruption of the microbiome population is closely associated with chronic metabolic diseases, such as nonalcoholic fatty liver disease (NAFLD). Gegen Qinlian decoction (GGQLD), a well-known traditional Chinese herbal medicine (CHM), was previously found to regulate lipid metabolism and attenuate inflammation during NAFLD pathogenesis. However, the underlying mechanism of this process, as well as how the gut microbiome is involved, remains largely unknown. In this study, we investigated the effect of varying doses of GGQLD on the total amount and distribution of gut bacteria in rats fed a high-fat diet (HFD) for 8 weeks. Our analysis indicates that Oscillibacter and Ruminococcaceae_g_unclassified are the dominant families in the HFD group. Further, HFD-dependent differences at the phylum, class, and genus levels appear to lead to dysbiosis, characterized by an increase in the Firmicutes/Bacteroidetes ratio and a dramatic increase in the Oscillibacter genus compared to the control group. Treatment with GGQLD, especially the GGQLL dose, improved these HFD-induced changes in intestinal flora, leading to increased levels of Firmicutes, Clostridia, Lactobacillus, bacilli, and Erysipelotrichales that were similar to the controls. Taken together, our data highlight the efficacy of GGQLD in treating NAFLD and support its clinical use as a treatment for NAFLD/NASH patients.

Metformin ameliorated methotrexate-induced hepatorenal toxicity in rats in addition to its antitumor activity: two birds with one stone

Methotrexate (MTX) is a drug used in treatment of various malignancies. Unfortunately, it leads to life-threatening complications including hepatorenal toxicity. Previous studies revealed the protective effects of metformin (MET) on hepatorenal toxicity in other models in addition to its anticancer effects. The current study investigates the effect of MET on MTX-induced hepatorenal toxicity and the possible mechanisms involved in this toxicity which can be overwhelmed by MET. Thirty male rats were divided into 3 groups: normal control, MTX treated and MET/MTX treated. After 7 days, MTX induced hepatorenal toxicity as proved by histological examinations and biochemical analysis of liver and kidney functions. Also, it led to significant increase in hepatic and renal malondialdehyde levels, significant decrease in hepatic and renal total antioxidant capacity levels and Na+/K+-ATPase activities and significant up regulation of mRNA expressions of nuclear factor kappa-light-chain-enhancer of activated B cells, cyclooxygenase-2 and caspase 3 compared with the control group. While, MET could significantly reduce hepatorenal toxicity and counteract the effects of MTX on all measured parameters. In conclusion, MET can be an effective adjuvant to MTX chemotherapy that could ameliorate its hepatorenal toxicity through antioxidant, anti-inflammatory and anti-apoptotic mechanisms.

Advancing the understanding of NAFLD to hepatocellular carcinoma development: From experimental models to humans

Nonalcoholic fatty liver disease (NAFLD) has recently been recognized as an important etiology contributing to the increased incidence of hepatocellular carcinoma (HCC). NAFLD, characterized by fat accumulation in the liver, is affecting at least one-third of the global population. The more aggressive form, nonalcoholic steatohepatitis (NASH), is characterized by hepatocyte necrosis and inflammation. The development of effective approaches for disease prevention and/or treatment heavily relies on deep understanding of the mechanisms underlying NAFLD to HCC development. However, this has been largely hampered by the lack of robust experimental models that recapitulate the full disease spectrum. This review will comprehensively describe the current in vitro and mouse models for studying NAFLD/NASH/HCC, and further emphasize their applications and possible future improvement for better understanding the molecular mechanisms involved in the cascade of NAFLD to HCC progression.

Gut microbiota translocation promotes autoimmune cholangitis

Gut microbiota and bacterial translocation have been implicated as significant contributors to mucosal immune responses and tolerance; alteration of microbial molecules, termed pathogen-associated molecular patterns (PAMP) and bacterial translocation are associated with immune pathology. However, the mechanisms by which dysregulated gut microbiota promotes autoimmunity is unclear. We have taken advantage of a well-characterized murine model of primary biliary cholangitis, dnTGFβRII mice, and an additional unique construct, toll-like receptor 2 (TLR2)-deficient dnTGFβRII mice coined dnTGFβRIITLR2-/- mice to investigate the influences of gut microbiota on autoimmune cholangitis. Firstly, we report that dnTGFβRII mice manifest altered composition of gut microbiota and that alteration of this gut microbiota by administration of antibiotics significantly alleviates T-cell-mediated infiltration and bile duct damage. Second, toll-like receptor 2 (TLR2)-deficient dnTGFβRII mice demonstrate significant exacerbation of autoimmune cholangitis when their epithelial barrier integrity was disrupted. Further, TLR2-deficiency mediates downregulated expression of tight junction-associated protein ZO-1 leading to increased gut permeability and bacterial translocation from gut to liver; use of antibiotics reduces microbiota translocation to liver and also decreases biliary pathology. In conclusion, our data demonstrates the important role of gut microbiota and bacterial translocation in the pathogenesis of murine autoimmune cholangitis.

Modulation of gut microbiome in nonalcoholic fatty liver disease: pro-, pre-, syn-, and antibiotics

Nonalcoholic fatty liver disease (NAFLD) is one of the most common types of liver diseases worldwide and its incidence continues to increase. NAFLD occurs when the body can no longer effectively store excess energy in the adipose tissue. Despite the increasing prevalence of NAFLD, making lifestyle changes, including increased exercise, is often an elusive goal for patients with NAFLD. The liver directly connects to the gut-gastrointestinal milieu via the portal vein, which are all part of the gut-liver axis. Therefore, the gut-microbiome and microbial products have been actively studied as likely key factors in NAFLD pathophysiology. Hence, dysbiosis of the gut microbiome and therapeutic manipulation of the gut-liver axis are being investigated. Novel therapeutic approaches for modulating gut microbiota through the administration of probiotics, prebiotics, synbiotics, and antibiotics have been proposed with numerous promising initial reports on the effectiveness and clinical applications of these approaches. This review delves into the current evidence on novel therapies that modulate gut microbiota and discusses ongoing clinical trials targeting the gut-liver axis for the management and prevention of NAFLD.

Meta-analysis of the effects of probiotic supplementation on glycemia, lipidic profiles, weight loss and C-reactive protein in women with polycystic ovarian syndrome

INTRODUCTION

Several studies have been designed to investigate the beneficial effects of probiotic supplementation on metabolic parameters and inflammation status in women with polycystic ovarian syndrome (PCOS), but results have been inconsistent. Herein, we perform a meta-analysis of randomized controlled trials (RCTs) to evaluate the effects of probiotic supplementation on glycemia control, lipidic profiles, weight loss and C-reactive protein (CRP) in women with PCOS.

EVIDENCE ACQUISITION

MELINE, EMBASE, and Cochrane Library were searched for RCTs that investigated the effects of probiotic in women with PCOS. Two investigators independently performed the screening, data extraction, and methodological quality assessment. Data were pooled as mean differences (MDs) with 95% confidence intervals (CIs). The statistical heterogeneity was assessed with the I2 test. Sensitivity analyses were performed by the leave-one-out approach.

EVIDENCE SYNTHESIS

From the literature search, 26 publications were screened and 6 RCTs involving 406 PCOS participants (aged 25-28.5 years) with follow-up period between 8-12 weeks were included. The pooled results showed that probiotic supplement significantly affected the levels of fasting blood insulin (FBI), quantitative insulin sensitivity check index (QUICKI), triglycerides (TG), and very low density lipoprotein-cholesterol (VLDL-C). However, no significant changes were found in other markers, including fasting plasma glucose, homeostatic model assessment-insulin resistance, total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, body weight, CRP, and dehydroepiandrosterone sulfate levels. The pooled result was robust after the sensitivity analysis.

CONCLUSIONS

Our finding provides evidence that daily probiotic consumption has beneficial effects on decreasing FBI, TG, and VLDL-C, and increasing the QUICKI score in PCOS patients.

Daily Consumption of Synbiotic Yogurt Decreases Liver Steatosis in Patients with Nonalcoholic Fatty Liver Disease: A Randomized Controlled Clinical Trial

Background

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in developed and developing countries. The use of synbiotics has been proposed as a probable management strategy for patients with NAFLD.

Objective

We investigated the effects of synbiotic yogurt on hepatic steatosis and liver enzymes as primary outcomes and on oxidative stress markers, adipokine concentration, and gut peptide concentration as secondary outcomes in patients with NAFLD.

Methods

In this 24-wk, open-label, randomized controlled clinical trial, 102 patients [50 men and 52 women; mean age: 40 y; body mass index (in kg/m2) (mean ± SD): 31.2 ± 4.9] were randomly assigned to 3 groups, including 2 intervention groups and 1 control group. The intervention groups consumed 300 g synbiotic yogurt containing 108 colony-forming units Bifidobacterium animalis/mL and 1.5 g inulin or conventional yogurt daily and were advised to follow a healthy lifestyle (i.e., diet and exercise). The control group was advised to follow a healthy lifestyle alone. We evaluated differences between groups in liver function measures by using repeated-measures ANOVA, ANCOVA, and logistic regression.

Results

At the end of the study, the grades of NAFLD, as determined by ultrasonography, showed a significant decrease in the synbiotic group compared with the conventional and control groups (P < 0.001). The following significant mean ± SD decreases were seen in the synbiotic, conventional, and control groups, respectively: serum concentration of alanine aminotransferase (-14.5 ± 15.6 compared with 4.6 ± 15.4 and 3.1 ± 14.4 IU/L; P = 0.008), aspartate aminotransferase (-7.5 ± 6.1 compared with 3.0 ± 8.2 and 3.1 ± 5.7 IU/L; P < 0.001), alkaline phosphatase (-26.2 ± 16.8 compared with 3.4 ± 30.1 and 1.5 ± 31.9 IU/L; P = 0.024), and γ-glutamyltransferase (-6.0 ± 6.0 compared with 1.0 ± 6.4 and 7.6 ± 11.4 IU/L; P < 0.001).

Conclusion

Synbiotic yogurt consumption improved hepatic steatosis and liver enzyme concentrations in patients with NAFLD. This trial was registered at the Iranian Registry of Clinical Trials website (www.irct.ir) as IRCT2017020932417N2.

Polystyrene microplastics induce gut microbiota dysbiosis and hepatic lipid metabolism disorder in mice

Microplastic (MP) has become a concerning global environmental problem. It is toxic to aquatic organisms and can spread through the food chain to ultimately pose a threat to humans. In the environment, MP can interact with microbes and act as a microbial habitat. However, effects of polystyrene MP on the gut microbiota in mammals remain unclear. Here, male mice were exposed to two different sizes of polystyrene MP for 5 weeks to explore its effect. We observed that oral exposure to 1000 μg/L of 0.5 and 50 μm polystyrene MP decreased the body, liver and lipid weights in mice. Mucus secretion in the gut decreased in both sizes of polystyrene MP-treated groups. Regarding the gut microbiota, at the phylum level, polystyrene MP exposure decreased the relative abundances of Firmicutes and α-Proteobacteria in the feces. Furthermore, high throughput sequencing of the V3-V4 region of the 16S rRNA gene revealed significant changes in the richness and diversity of the gut microbiota in the cecums of polystyrene MP-treated mice. At the genus level, a total of 6 and 8 types of bacteria changed in the 0.5 and 50 μm polystyrene MP-treated groups, respectively. Furthermore, an operational taxonomic unit (OTU) analysis identified that 310 and 160 gut microbes were changed in the 0.5 and 50 μm polystyrene MP-treated groups, respectively. In addition, the hepatic triglyceride (TG) and total cholesterol (TCH) levels decreased in both 1000 μg/L 0.5 and 50 μm polystyrene MP-treated groups. Correspondingly, the relative mRNA levels of some key genes related to lipogenesis and TG synthesis decreased in the liver and epididymal fat. These results indicated that polystyrene MP could modify the gut microbiota composition and induce hepatic lipid disorder in mice; while the mouse is a common mammal model, consequently, the health risks of MP to animals should not be ignored.

New Aspects of Lipotoxicity in Nonalcoholic Steatohepatitis

NASH is becoming increasingly common worldwide because of the growing global prevalence of obesity and consequently NAFLD. Unfortunately, the mechanism of progression of NAFLD to NASH and then cirrhosis is not completely understood. Several factors, including insulin resistance, inflammation, oxidative stress, lipotoxicity, and bile acid (BA) toxicity, have been reported to be associated with NASH progression. The release of fatty acids from dysfunctional and insulin-resistant adipocytes results in lipotoxicity, which is caused by the ectopic accumulation of triglyceride-derived toxic metabolites and the subsequent activation of inflammatory pathways, cellular dysfunction, and lipoapoptosis. Adipose tissue (AT), especially visceral AT, comprises multiple cell populations that produce adipokines and insulin-like growth factor, plus macrophages and other immune cells that stimulate the development of lipotoxic liver disease. These biomolecules have been recently linked with many digestive diseases and gastrointestinal malignancies such as hepatocellular carcinoma. This made us question what role lipotoxicity has in the natural history of liver fibrosis. Therefore, this review focuses on the close relationship between AT and NASH. A good comprehension of the pathways that are related to dysregulated AT, metabolic dysfunction, and hepatic lipotoxicity will result in the development of prevention strategies and promising therapeutics for patients with NASH.

Effect of Kombucha on gut-microbiota in mouse having non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver disorders. Possible links have been recently found between the gut-microbiota and the host metabolism in development of NAFLD and obesity. Therefore, understanding the changes in intestinal microbiota during the progression of NAFLD, is important. In this study, the effect of Kombucha tea (KT), obtained by microbial fermentation of sugared black tea, was investigated on gut-microbiota during the progression of NAFLD. The results indicated a decrease in Erysipelotrichia class by treatment with KT in comparison to the methionine/choline-deficient (MCD)-fed db/db mice. Allobaculum, Turicibacter, and Clostridium genera, were only detected in MCD-fed db/db mice and were decreased after treatment with KT, whereas Lactobacillus was more abundant in MCD + KT-fed mice than in MCD only-fed mice and Mucispirillum, was found only in the MCD + KT-fed mice group. Our results demonstrated that the change of intestinal microbiota was influenced by KT intake, contributing to combat NAFLD.

Variation in the Plasma Levels of Polyunsaturated Fatty Acids in Control vis-à-vis Nonalcoholic Fatty Liver Disease Subjects and Its Possible Association with Gut Microbiome

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are becoming a major cause of chronic liver diseases globally. Polyunsaturated fatty acids (PUFA) have been postulated as a potential treatment for NAFLD. They can be obtained from diet and are also endogenously synthesized by enzymes delta-6-desaturase (D6D), delta-5-desaturase, and elongases. The current study is aimed at investigating the differences in the intake and levels of plasma PUFA between NAFLD patients and controls in Asian Indians. This correlation further propelled a pilot study to check for the differences in the gut microbiome of NASH subjects versus controls.

METHODS

One hundred forty-seven subjects were recruited and were grouped into healthy controls and cases. Subjects filled a food frequency questionnaire to assess PUFA intake. Plasma samples were subjected to gas chromatography analysis. For characterizing the gut microbiome, fecal samples of 20 NASH and healthy controls were analyzed by 16s rRNA gene sequencing. Alpha and beta diversity metrics and taxonomic analysis were carried out.

RESULTS

Plasma levels of eicosapentaenoic acid, γ-linoleic acid and D6D enzyme activity were significantly lower in cases. Dietary intake of total n-6 and n-3 PUFA did not differ between the two groups. Relative abundance of Streptococcus and Clostridium ramosum was significantly higher in NASH patients compared with healthy controls.

CONCLUSION

This study demonstrates, for the first time, decreased D6D enzyme activity and plasma PUFA levels in NAFLD patients. Furthermore, it demonstrates gut dysbiosis in histologically proven NASH patients vis-à-vis healthy controls.

NAFLD and HIV: Do Sex, Race, and Ethnicity Explain HIV-Related Risk?

PURPOSE OF REVIEW

Here, we review the epidemiology, diagnosis, and management of non-alcoholic fatty liver disease (NAFLD) in the general population, discuss HIV-specific differences in NAFLD pathogenesis, and summarize what is known regarding differences in NAFLD by race/ethnicity and sex.

RECENT FINDINGS

The reported prevalence of NAFLD among people living with HIV varies by age, body mass index, comorbidity, and method of NAFLD diagnosis, but is generally thought to be greater among HIV-infected compared to HIV-uninfected populations. Minorities and women tend to experience poorer HIV treatment outcomes (Meditz et al. J Infect Dis. 203(4):442-51, 2011; Beer et al. Medicine (Baltimore). 95(13):e 3171, 2016; Gant et al. MMWR Morb Mortal Wkly Rep. 66(40):1065-72, 2017; Millett et al. Lancet. 380(9839):341-8, 2012; Wejnert et al. J Infect Dis. 213(5):776-83, 2016), and are at the greatest risk for significant weight gain with HIV treatment (Erlandson et al. Medicine (Baltimore). 95(46):e 5399, 2016). Thus, women and minorities living with HIV may be at a higher risk of developing NAFLD and progressive liver disease. Disparities in the diagnosis, progression, and prognosis of NAFLD and HIV-associated NAFLD may be, in part, explained by genetic and sex differences; however, data is limited.

The effects of synbiotic supplementation on hormonal status, biomarkers of inflammation and oxidative stress in subjects with polycystic ovary syndrome: a randomized, double-blind, placebo-controlled trial

BACKGROUND

To our knowledge, no reports are available indicating the effects of synbiotic supplementation on hormonal status, biomarkers of inflammation and oxidative stress in subjects with polycystic ovary syndrome (PCOS). This research was done to assess the effects of synbiotic supplementation on hormonal status, biomarkers of inflammation and oxidative stress in subjects with PCOS.

METHODS

This randomized double-blind, placebo-controlled trial was conducted on 60 subjects diagnosed with PCOS according to the Rotterdam criteria. Subjects were randomly assigned into two groups to take either synbiotic (n = 30) or placebo (n = 30) for 12 weeks. Endocrine, inflammation and oxidative stress biomarkers were quantified at baseline and after the 12-week intervention.

RESULTS

After the 12-week intervention, compared with the placebo, synbiotic supplementation significantly increased serum sex hormone-binding globulin (SHBG) (changes from baseline in synbiotic group: + 19.8 ± 47.3 vs. in placebo group: + 0.5 ± 5.4 nmol/L, p = 0.01), plasma nitric oxide (NO) (changes from baseline in synbiotic group: + 5.5 ± 4.8 vs. in placebo group: + 0.3 ± 9.1 μmol/L, p = 0.006), and decreased modified Ferriman Gallwey (mF-G) scores (changes from baseline in synbiotic group: - 1.3 ± 2.5 vs. in placebo group: - 0.1 ± 0.5, p = 0.01) and serum high-sensitivity C-reactive protein (hs-CRP) (changes from baseline in synbiotic group: - 950.0 ± 2246.6 vs. in placebo group: + 335.3 ± 2466.9 ng/mL, p = 0.02). We did not observe any significant effect of synbiotic supplementation on other hormonal status and biomarkers of oxidative stress.

CONCLUSIONS

Overall, synbiotic supplementation for 12 weeks in PCOS women had beneficial effects on SHBG, mFG scores, hs-CRP and NO levels, but did not affect other hormonal status and biomarkers of oxidative stress.

TRIAL REGISTRATION

This study was retrospectively registered in the Iranian website ( www.irct.ir ) for registration of clinical trials ( IRCT201509115623N53 ), on 2015-09-27.

An overview on the interplay between nutraceuticals and gut microbiota

Background

Nowadays, growing attention was being given to the alternative ways to prevent or treat diseases. Nutraceuticals are used increasingly for this purpose. Many of these are being used as alternative therapy. Classic therapy with synthetic drugs, although very effective, has many side effects. The term “nutraceuticals” refers to the link between the nutritional and pharmaceutical domains. Also, lately, many studies have been done to investigate the role of microbiota in maintaining health. There is the hypothesis that some of the health benefits of nutraceuticals are due to their ability to change the microbiota. The aim of this review was to emphasize the link between the most commonly used nutraceuticals, the microbiota and the health benefits.

Methods

We selected the articles in PubMed, published up to July 2017, that provided information about most used nutraceuticals, microbiota and health benefits. In this review, we incorporate evidence from various types of studies, including observational, in vitro and in vivo, clinical studies or animal experiments.

Results

The results demonstrate that many nutraceuticals change the composition of microbiota and can interfere with health status of the patients.

Discussion

There is evidence which sustains the importance of nutraceuticals in people’s health through microbiota but further studies are needed to complete the assessment of nutraceuticals in health benefit as a consequence of microbiota’s changing.

Gut : liver : brain axis: the microbial challenge in the hepatic encephalopathy

Hepatic encephalopathy (HE) is a debilitating neuropsychiatric condition often associated with acute liver failure or cirrhosis. Advanced liver diseases are characterized by a leaky gut and systemic inflammation. There is strong evidence that the pathogenesis of HE is linked to a dysbiotic gut microbiota and to harmful microbial by-products, such as ammonia, indoles, oxindoles and endotoxins. Increased concentrations of these toxic metabolites together with the inability of the diseased liver to clear such products is thought to play an important patho-ethiological role. Current first line clinical treatments target microbiota dysbiosis by decreasing the counts of pathogenic bacteria, blood endotoxemia and ammonia levels. This review will focus on the role of the gut microbiota and its metabolism in HE and advanced cirrhosis. It will critically assess data from different clinical trials measuring the efficacy of the prebiotic lactulose, the probiotic VSL#3 and the antibiotic rifaximin in treating HE and advanced cirrhosis, through gut microbiota modulation. Additionally data from Randomised Controlled Trials using pre-, pro- and synbiotic will be also considered by reporting meta-analysis studies. The large amount of existing data showed that HE is a clear example of how an altered gut microbiota homeostasis can influence and impact on physiological functions outside the intestine, with implication for host health at the systems level. Nevertheless, a strong effort should be made to increase the information on gut microbiota ecology and its metabolic function in liver diseases and HE.

Alcohol Modulation of the Postburn Hepatic Response

The widespread and rapidly increasing trend of binge drinking is accompanied by a concomitant rise in the prevalence of trauma patients under the influence of alcohol at the time of their injury. Epidemiological evidence suggests up to half of all adult burn patients are intoxicated at the time of admission, and the presence of alcohol is an independent risk factor for death in the early stages post burn. As the major site of alcohol metabolism and toxicity, the liver is a critical determinant of postburn outcome, and experimental evidence implies an injury threshold exists beyond which burn-induced hepatic derangement is observed. Alcohol may lower this threshold for postburn hepatic damage through a variety of mechanisms including modulation of extrahepatic events, alteration of the gut-liver axis, and changes in signaling pathways. The direct and indirect effects of alcohol may prime the liver for the second-hit of many overlapping physiologic responses to burn injury. In an effort to gain a deeper understanding of how alcohol potentiates postburn hepatic damage, the authors summarize possible mechanisms by which alcohol modulates the postburn hepatic response.

Targeting gut microbiota in hepatocellular carcinoma: probiotics as a novel therapy

Hepatocellular carcinoma (HCC), the most common primary liver cancer, is one of the dreaded complications of chronic liver disease. Recent experimental and clinical studies have revealed that the alteration of gut-liver axis plays a pivotal role in the onset of chronic liver diseases, including HCC. Altered gut microbiota and endotoxemia are increasingly recognized as critical components in promoting the progression of chronic liver diseases to HCC. Probiotics have been suggested as a novel, safe and cost-effective approach to prevent or treat HCC. Mechanisms by which probiotics exerts their anti-cancer effects include their ability to bind carcinogens, modulation of gut microbiota, improvement of intestinal barrier function, and immunomodulation. This review summarizes the literature findings of the changes in gut microbiota linked to HCC, and discusses the possible therapeutic implications of probiotics for HCC.

Intestinal Microbiome Shifts, Dysbiosis, Inflammation, and Non-alcoholic Fatty Liver Disease

Adverse fluctuations in the distribution of the intestinal microbiome cohort has been associated with the onset of intra- and extra-intestinal inflammatory conditions, like the metabolic syndrome (MetS) and it's hepatic manifestation, non-alcoholic fatty liver disease (NAFLD). The intestinal microbial community of obese compared to lean subjects has been shown to undergo configurational shifts in various genera, including but not limited to increased abundances of Prevotella, Escherichia, Peptoniphilus, and Parabacteroides and decreased levels of Bifidobacteria, Roseburia, and Eubacteria genera. At the phylum level, decreased Bacteroidetes and increased Firmicutes have been reported. The intestinal microbiota therefore presents an important target for designing novel therapeutic modalities that target extra-intestinal inflammatory disorders, such as NAFLD. This review hypothesizes that disruption of the intestinal-mucosal macrophage interface is a key factor in intestinal-liver axis disturbances. Intestinal immune responses implicated in the manifestation, maintenance and progression of NAFLD provide insights into the dialogue between the intestinal microbiome, the epithelia and mucosal immunity. The pro-inflammatory activity and immune imbalances implicated in NAFLD pathophysiology are reported to stem from dysbiosis of the intestinal epithelia which can serve as a source of hepatoxic effects. We posit that the hepatotoxic consequences of intestinal dysbiosis are compounded through intestinal microbiota-mediated inflammation of the local mucosa that encourages mucosal immune dysfunction, thus contributing important plausible insight in NAFLD pathogenesis. The administration of probiotics and prebiotics as a cure-all remedy for all chronic diseases is not advocated, instead, the incorporation of evidence based probiotic/prebiotic formulations as adjunctive modalities may enhance lifestyle modification management strategies for the amelioration of NAFLD.

Practical Dietary Recommendations for the Prevention and Management of Nonalcoholic Fatty Liver Disease in Adults

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide. In the absence of effective pharmacotherapies, clinical guidelines focus primarily on weight loss to treat this condition. Established consensus, evidence-based, and clinical dietary recommendations for NAFLD are currently lacking. The aim of this paper is to provide evidence-based practical dietary recommendations for the prevention and management of NAFLD in adults. A literature review focusing on established principles for the development of clinical practice recommendations was employed using the following criteria: based on substantial evidence, ensures risk minimization, is flexible for an individual patient approach, and is open to further modification as evidence emerges. The Practice-based Evidence in Nutrition classification system was used to grade these principles. Five key dietary recommendations were developed: 1) follow traditional dietary patterns, such as the Mediterranean diet; 2) limit excess fructose consumption and avoid processed foods and beverages with added fructose; 3) PUFAs, especially long-chain omega-3 rich foods and MUFAs, should replace SFAs in the diet; 4) replace processed food, fast food, commercial bakery goods, and sweets with unprocessed foods high in fiber, including whole grains, vegetables, fruits, legumes, nuts, and seeds; and 5) avoid excess alcohol consumption. Improving diet quality may reduce the incidence and progression of NAFLD and associated risk factors. Many of the benefits are likely to result from the collective effect of dietary patterns. High-quality research-in particular, randomized clinical trials assessing dietary interventions that focus on liver-specific endpoints-are needed as a priority.

Environmental peer pressure: CD4+ T cell help in tolerance and transplantation

The liver participates in a multitude of metabolic functions that are critical for sustaining human life. Despite constant encounters with antigenic-rich intestinal blood, oxidative stress, and metabolic intermediates, there is no appreciable immune response. Interestingly, patients undergoing orthotopic liver transplantation benefit from a high rate of graft acceptance in comparison to other solid organ transplant recipients. In fact, cotransplantation of a donor liver in tandem with a rejection-prone graft increases the likelihood of graft acceptance. A variety of players may account for this phenomenon including the interaction of intrahepatic antigen-presenting cells with CD4⁺ T cells and the preferential induction of forkhead box P3 (Foxp3) expression on CD4⁺ T cells following injurious stimuli. Ineffective insult management can cause chronic liver disease, which manifests systemically as the following: antibody-mediated disorders, ineffective antiviral and antibacterial immunity, and gastrointestinal disorders. These sequelae sharing the requirement of CD4⁺ T cell help to coordinate aberrant immune responses. In this review, we will focus on CD4⁺ T cell help due to the shared requirements in hepatic tolerance and coordination of extrahepatic immune responses. Overall, intrahepatic deviations from steady state can have deleterious systemic immune outcomes and highlight the liver's remarkable capacity to maintain a balance between tolerance and inflammatory response while simultaneously being inundated with a panoply of antigenic stimuli. Liver Transplantation 24 89-97 2018 AASLD.

Exploring the microbiome in health and disease

The analysis of human microbiome is an exciting and rapidly expanding field of research. In the past decade, the biological relevance of the microbiome for human health has become evident. Microbiome comprises a complex collection of microorganisms, with their genes and metabolites, colonizing different body niches. It is now well known that the microbiome interacts with its host, assisting in the bioconversion of nutrients and detoxification, supporting immunity, protecting against pathogenic microbes, and maintaining health. Remarkable new findings showed that our microbiome not only primarily affects the health and function of the gastrointestinal tract but also has a strong influence on general body health through its close interaction with the nervous system and the lung. Therefore, a perfect and sensitive balanced interaction of microbes with the host is required for a healthy body. In fact, growing evidence suggests that the dynamics and function of the indigenous microbiota can be influenced by many factors, including genetics, diet, age, and toxicological agents like cigarette smoke, environmental contaminants, and drugs. The disruption of this balance, that is called dysbiosis, is associated with a plethora of diseases, including metabolic diseases, inflammatory bowel disease, chronic obstructive pulmonary disease, periodontitis, skin diseases, and neurological disorders. The importance of the host microbiome for the human health has also led to the emergence of novel therapeutic approaches focused on the intentional manipulation of the microbiota, either by restoring missing functions or eliminating harmful roles. In the present review, we outline recent studies devoted to elucidate not only the role of microbiome in health conditions and the possible link with various types of diseases but also the influence of various toxicological factors on the microbial composition and function.

Preventing subclinical necrotic enteritis through Lactobacillus johnsonii BS15 by ameliorating lipid metabolism and intestinal microflora in broiler chickens

Increasing studies have focused on the beneficial effects of Lactobacillus johnsonii in certain diseases. Here, we studied the prevention ability of a probiotic strain, L. johnsonii BS15 on subclinical necrotic enteritis (SNE), and its underlying mechanism. 180 male Cobb 500 chicks were randomly allotted into three groups and administrated with BS15 (1 × 10⁶ cfu/g) or Man Rogosa Sharpe liquid medium throughout a 28-day experimental period. With the exception of the normal group, SNE infection was treated for the remaining experimental period after the chicks were fed with normal diet 14 days. Results showed that BS15 notably suppressed the SNE-induced loss of average daily gain and liver functional abnormality. Additionally, BS15 facilitated lipid metabolism of SNE boilers when the contents of peroxisome proliferator activated receptor γ and adipose triglyceride lipase in adipose tissue and serum high-density lipoprotein cholesterol decreased. BS15 also attenuated the hepatic lipid accumulation of stricken chicks by suppressing the genes expression of acetyl-CoA carboxylase, fatty acid synthase and sterol regulatory element binding protein-1c as well as stimulating the genes expression of peroxisome proliferator activated receptor α and carnitine palmitoyltransferase-1. Moreover, BS15 enhanced the development of SNE gut by improving the intestinal development and digestion as well as adjusting the gut microflora. Therefore, BS15 may provide a promising natural preventative strategy against SNE, which may be contributed to the amelioration of lipid metabolism and intestinal microflora.

Vitamin A deficiency in mice alters host and gut microbial metabolism leading to altered energy homeostasis

Vitamin A deficiency (A-) is a worldwide public health problem. To better understand how vitamin A status influences gut microbiota and host metabolism, we systematically analyzed urine, cecum, serum and liver samples from vitamin A sufficient (A+) and deficient (A-) mice using ¹H NMR-based metabolomics, quantitative (q)PCR and 16S rRNA gene sequencing coupled with multivariate data analysis. The microbiota in the cecum of A- mice showed compositional as well as functional shifts compared to the microbiota from A+ mice. Targeted ¹H NMR analyses revealed significant changes in microbial metabolite concentrations including higher butyrate and hippurate and decreased acetate and 4-hydroxyphenylacetate in A+ relative to A- mice. Bacterial butyrate-producing genes including butyryl-CoA:acetate CoA-transferase and butyrate kinase were significantly higher in bacteria from A+ versus bacteria from A- mice. A- mice had disturbances in multiple metabolic pathways including alterations in energy (hyperglycemia, glycogenesis, TCA cycle and lipoprotein biosynthesis), amino acid and nucleic acid metabolism. A- mice had hyperglycemia, liver dysfunction, changes in bacterial metabolism and altered gut microbial communities. Moreover, integrative analyses indicated a strong correlation between gut microbiota and host energy metabolism pathways in the liver. Vitamin A regulates host and bacterial metabolism, and the result includes alterations in energy homeostasis.

The gut-liver axis: impact of a mouse model of small-bowel bacterial overgrowth

BACKGROUND

The mechanisms by which intestinal bacteria impact liver diseases remain poorly understood. The aim of this study was to develop a mouse model of small-bowel bacterial overgrowth and to determine its impact on hepatobiliary injury.

MATERIALS AND METHODS

A jejunal self-filling blind loop (SFBL) was created in C57BL/6 mice. Three weeks after surgery, the mice were euthanized, and bacterial cultures of luminal content of the loop and extraintestinal tissues were performed. Liver and jejunum were collected for histological grading of inflammation and injury. Serum liver biochemistry assays were performed. Hepatobiliary transporter mRNA expression in liver was measured by quantitative real-time polymerase chain reaction. Bile and blood were collected for measurement of total bile acids, phospholipid, and cholesterol. Mice undergoing jejunal transection and reanastomosis and laparotomy only served as control groups.

RESULTS

SFBL induced a dramatic increase in intraluminal bacterial counts, mesenteric lymph node bacterial translocation, and evidence of jejunal and hepatobiliary injury. Significant reductions in hepatic expression of hepatobiliary transporters involved in biliary canalicular export and basolateral uptake were observed in SFBL mice. SFBL resulted in a significant increase in biliary total bile acid concentration, decreases in bile phospholipid and cholesterol output, and an increase in the bile acid/phospholipid ratio.

CONCLUSIONS

We have developed a reproducible mouse model of small-bowel bacterial overgrowth with evidence of liver inflammation, altered hepatobiliary transporter expression, and alterations in bile composition. This model may help to elucidate the mechanisms by which gut-derived bacterial factors impact the liver and contribute to the exacerbation of liver diseases and biliary injury.

Role of Probiotics in the Treatment of Nonalcoholic Fatty Liver Disease: A Meta-analysis

Aim:

Despite extensive ongoing research, there is scarcity of widely accepted therapeutic options for the treatment of nonalcoholic fatty liver disease (NAFLD). Probiotics are a promising treatment option for treating NAFLD; however, their effectiveness needs to be established. Since any single randomized controlled trial (RCT) cannot establish the role of probiotics in the treatment of NAFLD, this study aims at meta-analysis of different RCTs.

Materials and methods:

Extensive search was done by two independent observers for RCTs studying the role of probiotics in the treatment of NAFLD. The parameters under consideration were body mass index (BMI), aspartate aminotransferase (AST), alanine aminotransferase (ALT), homeostatic model assessment of insulin resistance (HOMA-IR), serum triglycerides (TGs), and ultrasonographic grades of fatty liver. Jadad scale was used to select the articles for meta-analysis. Heterogeneity in the results was evaluated using chi-square test and I². Significant heterogeneity in the results was decided based on p-value < 0.05 and the corresponding I² close to 0%.

Results:

Seven studies qualified for meta-analysis. Use of probiotics significantly caused reduction in BMI (p < 0.0001), ALT (p < 0.0001), AST (< 0.0001), HOMA-IR (p = 0.006), and ultrasonographic grade of fatty liver (p = 0.0051). Heterogeneity in other parameters was contributed mainly by couple of previous studies.

Conclusion:

Meta-analysis shows that variety of parameters has significant improvement after probiotic treatment in different RCTs. However, the magnitude of improvement is not uniform across studies due to varying strains, dose patterns, and treatment duration. In future, probiotics remain a promising option for treating NAFLD.

How to cite this article: Lavekar AS, Raje DV, Manohar T, Lavekar AA. Role of Probiotics in the Treatment of Nonalcoholic Fatty Liver Disease: A Meta-analysis. Euroasian J Hepato-Gastroenterol 2017;7(2):130-137.

Clostridium butyricum B1 alleviates high-fat diet-induced steatohepatitis in mice via enterohepatic immunoregulation

BACKGROUND AND AIM

Enterohepatic immunologic derangement is associated with non-alcoholic steatohepatitis. Here, we investigated whether Clostridium butyricum B1 (CB) would be an effective immune-targeted substance to attenuate steatohepatitis in mice.

METHODS

Thirty mice were randomized into a control group fed with common forage, a high-fat diet (HFD) group fed an HFD for 16 weeks, and an HFD + CB group treated with CB for the latter 8 weeks. Inflammation-associated or metabolism-associated genes in the liver or epididymal fat tissue were quantified; intrahepatic and intestinal immune factors were detected. Further short-chain fatty acids in the cecal contents or liver were measured, and differentiations of T cells in vitro were analyzed.

RESULTS

Characteristics of non-alcoholic steatohepatitis in the HFD group were obvious and were significantly attenuated in the HFD + CB group. The messenger RNA levels of monocyte chemotactic protein-1 and tumor necrosis factor-α in the liver and epididymal fat tissue were increased in the HFD group compared with the control group and were downregulated in the HFD + CB group. Intrahepatic and intestinal interferon-γ and interleukin (IL)-17 were significantly increased, whereas forkhead box P3, IL-4, and IL-22 were significantly decreased in the HFD group compared with the control group. However, these intrahepatic or intestinal immune changes were reversed after CB intervention. Furthermore, butyrate in the cecal content and liver of the HFD + CB group was significantly elevated. An in vitro investigation showed that sodium butyrate promoted CD4⁺ T cell differentiation into Th2, Th22, or Treg, whereas it inhibited CD4⁺ T cell differentiation into Th1 or Th17 under a cytokine milieu, which was mimicked by Trichostatin A.

CONCLUSION

Clostridium butyricum B1 could attenuate HFD-induced steatohepatitis in mice partially through butyrate-induced enterohepatic immunoregulation.

The pharmacological management of NAFLD in children and adolescents

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) represents a spectrum, including 'simple' steatosis, non-alcoholic steatohepatitis (NASH), and fibrosis. Increasing prevalence of NAFLD has followed the international rise in obesity and lifestyle modification is the mainstay therapy for children. To date, pharmacological trials have had varying efficacy but a large number of new agents are in early phase trials for adults. Areas covered: This review explores the effect of current and potential future paediatric NAFLD treatments in terms of histological and biochemical endpoints. The potential for the extension of adult treatments to children is discussed, as well as what limits the use of certain agents in children. Expert commentary: No drugs have yet to be licenced for NAFLD. Trial heterogeneity makes comparison of drugs between studies challenging. FXR agonists are yet to be trialled in children but may represent a safe and potentially efficacious therapy. Future treatments would likely encompass a multimodal approach that may include bariatric surgery.

Gut microbiota dysbiosis in patients with non-alcoholic fatty liver disease

BACKGROUND

Gut microbiota plays a significant role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). This study aimed to assess the contribution of gut microbiota dysbiosis to the pathogenesis of NAFLD.

METHODS

Forty-seven human feces samples (25 NAFLD patients and 22 healthy subjects) were collected and 16S rDNA amplicon sequencing was conducted on Hiseq 2000 platform. Discrepancy of species composition between controls and NAFLD group was defined by Metastats analysis under P value <0.01.

RESULTS

NAFLD patients harbored lower gut microbiota diversity than healthy subjects did. In comparison to the control group, the Proteobacteria (13.50%) and Fusobacteria (2.76%) phyla were more abundant in NAFLD patients. Additionally, the Lachnospiraceae (21.90%), Enterobacteriaceae (12.02%), Erysipelotrichaceae (3.83%), and Streptococcaceae (1.39%) families, as well as the Escherichia_Shigella (10.84%), Lachnospiraceae_Incertae_Sedis (7.79%), and Blautia (4.95%) genera were enriched in the NAFLD group. However, there was a lower abundance of Prevotella in the NAFLD group than that in the control group (5.83% vs 27.56%, P<0.01). The phylum Bacteroidetes (44.63%) also tended to be more abundant in healthy subjects, and the families Prevotellaceae (28.66%) and Ruminococcaceae (26.44%) followed the same trend. Compared to those without non-alcoholic steatohepatitis (NASH), patients with NASH had higher abundance of genus Blautia (5.82% vs 2.25%; P=0.01) and the corresponding Lachnospiraceae family (24.33% vs 14.21%; P<0.01). Patients with significant fibrosis had a higher abundance of genus Escherichia_Shigella (12.53% vs 1.97%; P<0.01) and the corresponding Enterobacteriaceae family (13.92% vs 2.07%; P<0.01) compared to those with F0/F1 fibrosis.

CONCLUSIONS

NAFLD patients and healthy subjects harbor varying gut microbiota. In contrast to the results of previous research on children, decreased levels of Prevotella might be detrimental for adults with NAFLD. The increased level of the genus Blautia, the family Lachnospiraceae, the genus Escherichia_Shigella, and the family Enterobacteriaceae may be a primary contributor to NAFLD progression.

THE EFFICACY OF ERADICATION OF SMALL INTESTINAL BACTERIAL OVERGROWTH IN PATIENTS WITH NON-ALCOHOLIC FATTY LIVER DISEASE

Background. Emerging evidence suggests a strong interaction between the gut, gut microbiota and liver. Derangement of gut flora, particularly small intestinal bacterial overgrowth (SIBO), occurs in a large percentage of patients with non-alcoholic fatty liver disease (NAFLD) and plays an important role in its pathogenesis. Aim. Study of the frequency of SIBO in various forms of non-alcoholic fatty liver disease, as well as the possibilities of its pathomorphosis as a result of eradication of SIBO as a result of the use of rifaximin or multicomponent probiotic. Material and methods. There were investigated 125 patients with non-alcoholic fatty liver disease (70 men, 55 women aged 18 to 65 years, mean age 37±6.7 years) developed at obesity or type 2 diabetes mellitus, including 85 patients with liver steatosis (group1) and 40 patients with non-alcoholic steatohepatitis (group 2). Patients with concomitant SIBO (70 patients) was treated with rifaximin or multicomponent probiotic. As the main endpoints of the study, the frequency of achieving eradication of SIBO was evaluated (estimated from the results of a repeated H2-lactulose hydrogen test after treatment), as well as a decrease in the severity of liver steatosis by steatometry and a decrease / normalization of transaminase levels 3 months after the start of the treatment. Secondary endpoints included the change in BMI and the HOMA-IR index 3 months after the start of the treatment. Results. SIBO in patients with non-alcoholic fatty liver disease was significantly more frequent than in control (p <0.005), and in patients with non-alcoholic steatohepatitis – significantly more often than in patients with liver steatosis (80 % vs 47.1 %, P <0.01). Eradication of SIBO after use of rifaximin was recorded in 30 of 36 patients with non-alcoholic fatty liver disease (83.3 %), including 16 of 20 patients with steatosis (80 %) and 14 of 16 (87.5 %) patients with non-alcoholic steatohepatitis. In the group of patients taking multicomponent probiotics after treatment, eradication of SIBO was noted in 12 of 36 patients (33.3 %), including 7 patients with steatosis (35 %) and 5 patients (31.3 %) with non-alcoholic steatohepatitis Conclusion. The investigation shows that the eradication of small intestinal bacterial overgrowth has the positive influence on the natural course of NAFLD and use of rifaximine should be discussed as a perspective therapeutic strategy at this pathology

New insight into inter-organ crosstalk contributing to the pathogenesis of non-alcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver dysfunction and a significant global health problem with substantial rise in prevalence over the last decades. It is becoming increasingly clear that NALFD is not only predominantly a hepatic manifestation of metabolic syndrome, but also involves extra-hepatic organs and regulatory pathways. Therapeutic options are limited for the treatment of NAFLD. Accordingly, a better understanding of the pathogenesis of NAFLD is critical for gaining new insight into the regulatory network of NAFLD and for identifying new targets for the prevention and treatment of NAFLD. In this review, we emphasize on the current understanding of the inter-organ crosstalk between the liver and peripheral organs that contributing to the pathogenesis of NAFLD.

Effects of Probiotic and Prebiotic Supplementation on Leptin, Adiponectin, and Glycemic Parameters in Non-alcoholic Fatty Liver Disease: A Randomized Clinical Trial

BACKGROUND

According to previous studies, probiotic and prebiotic supplementation have desirable effects on glycemic parameters. Thus far, the effect of supplementation on the glycemic parameters and adipokines in non-alcoholic fatty liver disease (NAFLD) has not been assessed. Therefore, the aim of this study was to determine the effects of supplementation with probiotic and prebiotic on adiokines and glycemic parameters in the patients with NAFLD.

METHODS

In the present randomized, double-blind, placebo-controlled trial, 89 patients with NAFLD were randomly divided into three groups to receive one probiotic capsule + 16 g/d maltodextrin (probiotic group) or 16 g/d oligofructose powder + one placebo capsule (prebiotic group), and one placebo capsule + 16 g/d maltodextrin (control group) for 12 weeks. All the subjects in the study were advised to follow the weight loss diet and physical activity recommendations during the intervention. Fasting blood samples were taken at baseline and after the intervention to measure leptin, adiponectin, insulin, and fasting blood sugar.

RESULTS

At the end of the study, serum concentrations of leptin, insulin, and HOMA-IR decreased significantly in the probiotic and prebiotic groups compared with the control group. Despite the changes within the groups, serum concentrations of adiponectin did not change significantly between the three groups. Also, fasting blood sugar did not change between the groups, but decreased in the prebiotic group. Quantitative insulin-sensitivity check index (QUICKI) increased significantly in probiotic and prebiotic groups compared with the control group.

CONCLUSION

Probiotic and prebiotic supplementation along with lifestyle intervention has a favorable impact on glycemic parameters and leptin levels compared with lifestyle intervention alone.

Microbiome and NAFLD: potential influence of aerobic fitness and lifestyle modification

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease with prevalence rates that are on the rise in the US and worldwide. NAFLD encompasses a spectrum of liver pathologies including simple steatosis to nonalcoholic steatohepatitis (NASH) with inflammation and fibrosis. The gut microbiome has emerged as a potential therapeutic target in combating metabolic diseases including obesity, Type 2 diabetes, and NAFLD/NASH. Diet-induced obesity/Western style diet feeding causes severe microbial dysbiosis initiating a microbiome signature that promotes metabolite production that directly impacts hepatic metabolism. Changes in lifestyle (i.e., diet, exercise, and aerobic fitness) improve NAFLD outcomes and can significantly influence the microbiome. However, directly linking lifestyle-induced remodeling of the microbiome to NAFLD pathogenesis is not well understood. Understanding the reshaping of the microbiome and the metabolites produced and their subsequent actions on hepatic metabolism are vital in understanding the gut-liver axis. In this review, we 1) discuss microbiome-derived metabolites that significantly contribute to the gut-liver axis and are directly linked to NAFLD/NASH and 2) present evidence on lifestyle modifications reshaping the microbiome and the potential therapeutic aspects in combating the disease.