Randomised clinical trial: The beneficial effects of VSL#3 in obese children with non-alcoholic steatohepatitis

Lifestyle and Dietary Interventions in the Management of Nonalcoholic Fatty Liver Disease

NAFLD is the leading cause of chronic liver disease in the Western world with an estimated prevalence of 20-30 %. Lifestyle interventions targeted at weight loss through dietary interventions and exercise are the most effective treatment, but only a minority of patients are able to achieve and sustain the necessary intervention targets. Weight loss of 3-5 % has been associated with a reduction of hepatic steatosis while weight loss of ≥5-7 % has correlated with resolution of NASH in some studies. Greater reductions in weight loss (≥10 %) may improve hepatic fibrosis. In the absence of weight loss, no specific diet has demonstrated superiority. Physical activity can improve hepatic steatosis and metabolic indices even without weight loss. Diet coupled with exercise can produce significant weight loss and may improve histologic components of the NAFLD activity score. While formal guidelines for diet and exercise in NAFLD are lacking, adherence to diet and exercise recommendations similar to those from the American Diabetes Association for diabetic care seems reasonable. Dietary supplementation with vitamin E in non-diabetics with biopsy-proven NASH has been shown to improve NAFLD activity score. The role for other macronutrients, micronutrients, antioxidants, and probiotics in the treatment of NAFLD remains limited.

Gut Microbiota of Nonalcoholic Fatty Liver Disease

The prevalence of nonalcoholic fatty liver disease has been rapidly increasing worldwide. It has become a leading cause of liver transplantation. Accumulating evidence suggests a significant role for gut microbiota in its development and progression. Here we review the effect of gut microbiota on developing hepatic fatty infiltration and its progression. Current literature supports a possible role for gut microbiota in the development of liver steatosis, inflammation and fibrosis. We also review the literature on possible interventions for NAFLD that target the gut microbiota.

Nonalcoholic Fatty Liver Disease and the Gut Microbiome

Recent progress has allowed a more comprehensive study of the gut microbiota. Gut microbiota helps in health maintenance and gut dysbiosis associates with chronic metabolic diseases. Modulation of short-chain fatty acids and choline bioavailability, lipoprotein lipase induction, alteration of bile acid profile, endogenous alcohol production, or liver inflammation secondary to endotoxemia result from gut dysbiosis. Modulation of the gut microbiota by pre/probiotics gives promising results in animal, but needs to be evaluated in human before use in clinical practice. Gut microbiota adds complexity to the pathophysiology of nonalcoholic fatty liver disease but represents an opportunity to discover new therapeutic targets.

Lifestyle Interventions Including Nutrition, Exercise, and Supplements for Nonalcoholic Fatty Liver Disease in Children

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of liver disease among children. Lifestyle interventions, such as diet and exercise, are frequently recommended. Children with NAFLD have a distinct physiology that is different from obesity alone and has the potential to influence lifestyle treatments. Studies of diet alone in the treatment of pediatric NAFLD have focused on sugar and carbohydrate, but did not indicate any one dietary approach that was superior to another. For children who are obese and have NAFLD, weight loss may have a beneficial effect regardless of the diet used. Exercise is widely believed to improve NAFLD because a sedentary lifestyle, poor aerobic fitness, and low muscle mass are all risk factors for NAFLD. However, there have been no randomized controlled trials of exercise as a treatment for children with NAFLD. Studies of the combination of diet and exercise suggest a potential for improvement in serum alanine aminotransferase activity and/or magnetic resonance imaging liver fat fraction with intervention. There is also enthusiasm for the use of dietary supplements; however, studies in children have shown inconsistent effects of vitamin E, fish oil, and probiotics. This review presents the available data from studies of lifestyle intervention and dietary supplements published to date and highlights challenges that must be addressed in order to advance the evidence base for the treatment of pediatric NAFLD.

Mechanisms Linking the Gut Microbiome and Glucose Metabolism

This review details potential mechanisms linking gut dysbiosis to metabolic dysfunction, including lipopolysaccharide, bile acids, short chain fatty acids, gut hormones, and branched-chain amino acids.

Protective effects of Lactobacillus rhamnosus GG against dyslipidemia in high-fat diet-induced obese mice

Recent reports suggest that gut microbiota can be a major determinant of dyslipidemia and non-alcoholic fatty liver disease (NAFLD) and its modulation by treating probiotics is a valid strategy to exert a protective effect. In this study, high-fat diet (HFD)-fed mice were orally administrated with Lactobacillus rhamnosus GG (LGG) for 13 weeks. Significant reductions in the weights of the liver, mesenteric and subcutaneous adipose tissues were observed in LGG-treated HFD-fed mice compared to LGG-non-treated controls. The serum levels of triglyceride and cholesterol were also significantly reduced in LGG-treated mice. Gut microbial composition analysis showed that shifts in the diversity of dominant gut bacteria were caused by HFD and restored by LGG treatment. A remarkable decrease of hepatic fat content was also observed in LGG-treated mice, accompanied by downregulated expressions of lipogenic and pro-inflammatory genes in the liver. LGG-treated mice had lower expression levels of genes involved in cholesterol synthesis, but conversely, higher expression levels of cholesterol efflux-related genes compared to LGG-non-treated controls. The cholesterol-lowering effect of LGG was also found to be mediated by suppression of FXR and FGF15 signaling, resulting in the upregulation of hepatic CYP7A1. Our findings confirm a therapeutic potential of probiotics for ameliorating dyslipidemia and NAFLD.

Fatty liver disease and obesity in youth

PURPOSE OF REVIEW

The purpose of this short review is to summarize recent developments in the understanding of pediatric nonalcoholic fatty liver disease (NAFLD), focusing on novel findings in pathogenetic mechanisms and the therapeutic armamentarium.

RECENT FINDINGS

As a result of the increasing prevalence of pediatric obesity, NAFLD has rapidly become the most common cause of chronic hepatopathies in children. Lifestyle modification and diet remain the mainstay of treatment of pediatric obesity and NAFLD, but with disappointing results because of the difficulty in obtaining sustained long-term results. Considering the risk of progression of liver damage to cirrhosis and end-stage liver disease, in the last decades scientific research in this field has been directed to the identification of pathogenetic mechanisms and possible therapeutic strategies for NAFLD.

SUMMARY

We describe the therapeutic options for the management of pediatric NAFLD, focusing on emerging alternative strategies, including surgical approaches and new drugs directed against novel potential molecular targets.

Probiotic supplementation and trimethylamine-N-oxide production following a high-fat diet

OBJECTIVE

The objective of this study was to test the hypothesis that the multi-strain probiotic VSL#3 would attenuate the increase in fasting plasma concentrations of trimethylamine-N-oxide (TMAO) following a high-fat diet.

METHODS

Nineteen healthy, non-obese males (18-30 years) participated in the present study. Following a 2-week eucaloric control diet, subjects were randomized to either VSL#3 (900 billion live bacteria) or placebo (cornstarch) during the consumption of a hypercaloric (+1,000 kcal day(-1) ), high-fat diet (55% fat) for 4 weeks. Plasma TMAO, L-carnitine, choline, and betaine (UPLC-MS/MS) were measured at baseline and following a high-fat diet.

RESULTS

Plasma TMAO significantly increased 89% ± 66% vs. 115% ± 61% in both the VSL#3 and placebo groups, respectively; however, the magnitude of change in plasma TMAO was not different (P > 0.05) between them. Plasma L-carnitine, choline, and betaine concentrations did not increase following the high-fat diet in either group.

CONCLUSIONS

A high-fat diet increases plasma TMAO in healthy, normal-weight, young males. However, VSL#3 treatment does not appear to influence plasma TMAO concentrations following a high-fat diet. Future studies are needed to determine whether other therapeutic strategies can attenuate the production of TMAO.

Dietary supplements and pediatric non-alcoholic fatty liver disease: Present and the future

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in children. High prevalence of pediatric obesity and sedentary lifestyle has augmented the incidence of NAFLD in children. Obesity is associated with an increased risk of NAFLD through various mechanisms such as intensification of insulin resistance and increased levels of inflammatory markers. There is no approved medical intervention for treatment of pediatric NAFLD; the only proven strategy in management of pediatric NAFLD is lifestyle modification. Recently, the effects of nutritional supplements have been examined in the management of pediatric NAFLD. The purpose of this review is to summarize the studies evaluating the effects of nutritional supplements on pediatric NAFLD and explain the future direction in this field.

Probiotics in Pediatric Liver Disease

The gut-liver axis involves complex interaction between the intestinal microbiome and the liver parenchyma. Probiotics are live microorganisms that are used in a variety of diseases. With currently only 2 randomized-controlled studies (one with Lactobacillus GG and the other with VSL #3), data are scarce to support the clinical effect of probiotic use in children with nonalcoholic fatty liver disease. There is evidence that probiotics decrease the risk of necrotizing enterocolitis and thereby reduce the prevalence of total parenteral nutrition-induced chronic liver disease. Probiotics are used with a few reported positive outcomes in patients with cystic fibrosis and familial hypercholesterolemia and may be promising in other liver conditions. Probiotics are generally safe and well tolerated in children, premature infants, and in patients after liver transplantation. Large, prospective, randomized clinical trials are needed to evaluate the benefit of probiotics in children with liver diseases.

Role of the Gut Microbiome in Nonalcoholic Fatty Liver Disease

The incidence of nonalcoholic fatty liver disease (NAFLD) continues to increase with prevalence estimates ranging from 17%-33%, making it is the most common cause of chronic liver disease in North America. Its importance is due to not only its prevalence but also its association with increased cardiovascular morbidity and progression to cirrhosis in a subset of patients. NAFLD encompasses a pathologic spectrum of disease, from relatively benign accumulation of lipid (steatosis) to progressive nonalcoholic steatohepatitis associated with inflammation, fibrosis, and necrosis. Nonalcoholic steatohepatitis remains an important phenotypic state because this subgroup of patients is deemed at high risk for developing cirrhosis and progressing to liver failure requiring transplantation or to death. Gut microbiota has recently been identified as regulators of energy homeostasis and fat deposition, thereby implicating them in the development of obesity and associated metabolic diseases. The growing evidence that alteration in gut microbiota (dysbiosis) may affect liver pathology may allow for a better understanding of its role in the pathogenesis of NAFLD, help to identify patients at risk of progression, and expose a microbial target for prevention and therapeutic intervention. In this review, we discuss the growing evidence that highlights the relationship between gut microbiota and its association with NAFLD.

Nutritional modulation of gut microbiota - the impact on metabolic disease pathophysiology

The obesity epidemic afflicts over one third of the United States population. With few therapies available to combat obesity, a greater understanding of the systemic causes of this and other metabolic disorders is needed to develop new, effective treatments. The mammalian intestinal microbiota contributes to metabolic processes in the host. This review summarizes the research demonstrating the interplay of diet, intestinal microbiota and host metabolism. We detail the effects of diet-induced modifications in microbial activity and resultant impact on (1) sensory perception of macronutrients and total energy intake; (2) nutrient absorption, transport and storage; (3) liver and biliary function; (4) immune-mediated signaling related to adipose inflammation; and (5) circadian rhythm. We also discuss therapeutic strategies aimed to modify host-microbe interactions, including prebiotics, probiotics and postbiotics, as well as fecal microbiota transplantation. Elucidating the role of gut microbes in shaping metabolic homeostasis or dysregulation provides greater insight into disease development and a promising avenue for improved treatment of metabolic dysfunction.

Effects of synbiotic on anthropometry, lipid profile and oxidative stress in obese children

Recent studies have suggested some beneficial effects of probiotics and/or prebiotics on obesity in adults; such experience is limited in children and adolescents. This study was an open-label, randomised, controlled study including children with primary obesity. The first group was treated with a standard method with a reduced calorie intake and increased physical activity. The second group received add-on daily synbiotic supplementation during one month. The aim of this study was to evaluate potential effects of a synbiotic on anthropometric measurements, lipid profile and oxidative stress parameters. One month of supplementation of the synbiotic resulted in a significant reduction of weight (P<0.001) and body mass index (P<0.01). Changes (% reduction comparing to baseline) in anthropometric measurements, were significantly higher in the children receiving the additional synbiotic supplement (P<0.05). The percentage of children with weight loss was higher in the synbiotic group, but not statistically significant (71.4 vs 64.2%, P>0.05). At the 30(th) day of synbiotic intervention, serum total cholesterol, low density lipoprotein cholesterol and total oxidative stress levels significantly declined (P<0.05). Changes in serum lipid levels were significantly higher in the synbiotic group (P<0.05). Changes in serum total oxidative stress levels before and after the intervention period, were significant in synbiotic group (P<0.01). In our study, changes in weight, body mass index, and triceps skinfold thickness were higher in the group receiving the one month synbiotic supplement thin in the standard method group. The supplement tested also had a beneficial effect on lipid profile and total oxidative stress. To the best of our knowledge, this is the first study showing the effects of synbiotics on oxidative stress in obese patients with an additional effect on weight loss regarding to previous studies.

Gut-liver axis, nutrition, and non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) represents a spectrum of diseases involving hepatic fat accumulation, inflammation with the potential progression to fibrosis and cirrhosis over time. NAFLD is often associated with obesity, insulin resistance, and diabetes. The interactions between the liver and the gut, the so-called "gut-liver axis", play a critical role in NAFLD onset and progression. Compelling evidence links the gut microbiome, intestinal barrier integrity, and NAFLD. The dietary factors may alter the gut microbiota and intestinal barrier function, favoring the occurrence of metabolic endotoxemia and low grade inflammation, thereby contributing to the development of obesity and obesity-associated fatty liver disease. Therapeutic manipulations with prebiotics and probiotics to modulate the gut microbiota and maintain intestinal barrier integrity are potential agents for NAFLD management. This review summarizes the current knowledge regarding the complex interplay between the gut microbiota, intestinal barrier, and dietary factors in NAFLD pathogenesis. The concepts addressed in this review have important clinical implications, although more work needs to be done to understand how dietary factors affect the gut barrier and microbiota, and to comprehend how microbe-derived components may interfere with the host's metabolism contributing to NAFLD development.

The Influence of the Gut Microbiome on Obesity, Metabolic Syndrome and Gastrointestinal Disease

There is a fine balance in the mutual relationship between the intestinal microbiota and its mammalian host. It is thought that disruptions in this fine balance contribute/account for the pathogenesis of many diseases. Recently, the significance of the relationship between gut microbiota and its mammalian host in the pathogenesis of obesity and the metabolic syndrome has been demonstrated. Emerging data has linked intestinal dysbiosis to several gastrointestinal diseases including inflammatory bowel disease, irritable bowel syndrome, nonalcoholic fatty liver disease, and gastrointestinal malignancy. This article is intended to review the role of gut microbiota maintenance/alterations of gut microbiota as a significant factor as a significant factor discriminating between health and common diseases. Based on current available data, the role of microbial manipulation in disease management remains to be further defined and a focus for further clinical investigation.

Gut Microbiota: Association with NAFLD and Metabolic Disturbances

Nonalcoholic fatty liver disease is the hepatic expression of metabolic syndrome, being frequently associated with obesity, insulin resistance, and dyslipidemia. Recent lines of evidence have demonstrated a role of gut microbiota in insulin resistance, obesity, and associated metabolic disturbances, raising the interest in its relationship with NAFLD pathogenesis. Therefore, intestinal microbiota has emerged as a potential factor involved in NAFLD, through different pathways, including its influence in energy storage, lipid and choline metabolism, ethanol production, immune balance, and inflammation. The main objective of this review is to address the pathogenic association of gut microbiota to NAFLD. This comprehension may allow the development of integrated strategies to modulate intestinal microbiota in order to treat NAFLD.

Urinary (1)H-NMR-based metabolic profiling of children with NAFLD undergoing VSL#3 treatment

BACKGROUND

Nowadays, non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases in children. Our recent clinical trial demonstrated that dietary and VSL#3-based interventions may improve fatty liver by ultrasound and body mass index (BMI) after 4 months.

OBJECTIVES

As in this short-term trial, as in others, it is impracticable to monitor response to therapy or treatment by liver biopsy, we aimed to identify a panel of potential non-invasive metabolic biomarkers by a urinary metabolic profiling.

METHODS

Urine samples from a group of 31 pediatric NAFLD patients, enrolled in a VSL#3 clinical trial, were analyzed by high-resolution proton nuclear magnetic resonance spectroscopy in combination with analysis of variance-Simultaneous Component Analysis model and multivariate data analyses. Urinary metabolic profiles were interpreted in terms of clinical patient feature, treatment and chronology pattern correlations.

RESULTS

VSL#3 treatment induced changes in NAFLD urinary metabolic phenotype mainly at level of host amino-acid metabolism (that is, valine, tyrosine, 3-amino-isobutyrate or β-aminoisobutyric acid (BAIBA)), nucleic acid degradation (pseudouridine), creatinine metabolism (methylguanidine) and secondarily at the level of gut microbial amino-acid metabolism (that is, 2-hydroxyisobutyrate from valine degradation). Furthermore, some of these metabolites correlated with clinical primary and secondary trial end points after VSL#3 treatment: tyrosine and the organic acid U4 positively with alanine aminotransferase (R=0.399, P=0.026) and BMI (R=0.36, P=0.045); BAIBA and tyrosine negatively with active glucagon-like-peptide 1 (R=-0.51, P=0.003; R=-0.41, P=0.021, respectively).

CONCLUSIONS

VSL#3 treatment-dependent urinary metabotypes of NAFLD children may be considered as non-invasive effective biomarkers to evaluate the response to treatment.

A concise review of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome and the incidence of which is rising rapidly due to the increasing epidemic of obesity in both adults and children. The initial accumulation of fat followed by subsequent inflammation is central to the development of liver damage, and is critically influenced by host factors including age, gender, presence of diabetes, genetic polymorphisms and more recently by the gut microbiome. An increasing body of data suggest that NAFLD is also an independent risk factor of cardiovascular disease, which remains the commonest cause of mortality in such patients. This review focusses on the pathogenesis of NAFLD, and the evolution of new approaches to the management and treatment of NAFLD.

Systematic review on intervention with prebiotics/probiotics in patients with obesity-related nonalcoholic fatty liver disease

BACKGROUND

The gut microbiota is modulated by metabolic derangements, such as nutrition overload and obesity.

AIM

The aim of this systematic review is to summarize the role of these gut modifiers in nonalcoholic fatty liver disease (NAFLD) and obesity.

METHODS

A systematic search of MEDLINE (from 1946), PubMed (from 1946) and EMBASE (from 1949) databases through May 2014 was carried out to identify relevant articles. The search terms were 'probiotic' AND 'NAFLD', 'prebiotic' AND 'NAFLD', 'antibiotic' AND 'NAFLD', 'probiotics' AND 'obesity', 'prebiotic' AND 'obesity' or 'antibiotic' AND 'obesity'; these terms were searched as text word in 'clinical trials' and as exploded medical subject headings where possible.

RESULTS

The evidence in the literature is scant, due to the scarcity of appropriately powered, randomized, controlled clinical trials, involving various centers and population of different origin.

CONCLUSION

Although probiotics and prebiotics have been proposed in the treatment and prevention of patients with obesity-related NAFLD, their therapeutic use is not supported by high-quality clinical studies.

Childhood obesity: a role for gut microbiota?

Obesity is a serious public health issue affecting both children and adults. Prevention and management of obesity is proposed to begin in childhood when environmental factors exert a long-term effect on the risk for obesity in adulthood. Thus, identifying modifiable factors may help to reduce this risk. Recent evidence suggests that gut microbiota is involved in the control of body weight, energy homeostasis and inflammation and thus, plays a role in the pathophysiology of obesity. Prebiotics and probiotics are of interest because they have been shown to alter the composition of gut microbiota and to affect food intake and appetite, body weight and composition and metabolic functions through gastrointestinal pathways and modulation of the gut bacterial community. As shown in this review, prebiotics and probiotics have physiologic functions that contribute to changes in the composition of gut microbiota, maintenance of a healthy body weight and control of factors associated with childhood obesity through their effects on mechanisms controlling food intake, fat storage and alterations in gut microbiota.

Intestinal microbiota and type 2 diabetes: From mechanism insights to therapeutic perspective

The incidence of type 2 diabetes (T2DM) is rapidly increasing worldwide. However, the pathogenesis of T2DM has not yet been well explained. Recent evidence suggests that the intestinal microbiota composition is associated with obesity and T2DM. In this review, we provide an overview about the mechanisms underlying the role of intestinal microbiota in the pathogenesis of T2DM. There is clear evidence that the intestinal microbiota influences the host through its effect on body weight, bile acid metabolism, proinflammatory activity and insulin resistance, and modulation of gut hormones. Modulating gut microbiota with the use of probiotics, prebiotics, antibiotics, and fecal microbiota transplantation may have benefits for improvement in glucose metabolism and insulin resistance in the host. Further studies are required to increase our understanding of the complex interplay between intestinal microbiota and the host with T2DM. Further studies may be able to boost the development of new effective therapeutic approaches for T2DM.

Gut-liver axis and probiotics: Their role in non-alcoholic fatty liver disease

The incidence of obesity and its related conditions, including non-alcoholic fatty liver disease (NAFLD), has dramatically increased in all age groups worldwide. Given the health consequences of these conditions, and the subsequent economic burden on healthcare systems, their prevention and treatment have become major priorities. Because standard dietary and lifestyle changes and pathogenically-oriented therapies (e.g., antioxidants, oral hypoglycemic agents, and lipid-lowering agents) often fail due to poor compliance and/or lack of efficacy, novel approaches directed toward other pathomechanisms are needed. Here we present several lines of evidence indicating that, by increasing energy extraction in some dysbiosis conditions or small intestinal bacterial overgrowth, specific gut microbiota and/or a “low bacterial richness” may play a role in obesity, metabolic syndrome, and fatty liver. Under conditions involving a damaged intestinal barrier (“leaky gut”), the gut-liver axis may enhance the natural interactions between intestinal bacteria/bacterial products and hepatic receptors (e.g., toll-like receptors), thus promoting the following cascade of events: oxidative stress, insulin-resistance, hepatic inflammation, and fibrosis. We also discuss the possible modulation of gut microbiota by probiotics, as attempted in NAFLD animal model studies and in several pilot pediatric and adult human studies. Globally, this approach appears to be a promising and innovative add-on therapeutic tool for NAFLD in the context of multi-target therapy.

Non-alcoholic fatty liver disease in children: focus on nutritional interventions

With increasing prevalence of childhood obesity, non-alcoholic fatty liver disease (NAFLD) has emerged as the most common cause of liver disease among children and adolescents in industrialized countries. It is generally recognized that both genetic and environmental risk factors contribute to the pathogenesis of NAFLD. Recently, there has been a growing body of evidence to implicate altered gut microbiota in the development of NAFLD through the gut-liver axis. The first line of prevention and treatment of NAFLD in children should be intensive lifestyle interventions such as changes in diet and physical activity. Recent advances have been focused on limitation of dietary fructose and supplementation of antioxidants, omega-3 fatty acids, and prebiotics/probiotics. Convincing evidences from both animal models and human studies have shown that reduction of dietary fructose and supplement of vitamin E, omega-3 fatty acids, and prebiotics/probiotics improve NAFLD.