Probiotics improve high fat diet-induced hepatic steatosis and insulin resistance by increasing hepatic NKT cells

The role of diet and intestinal microbiota in the development of metabolic syndrome

Metabolic syndrome (MetS) is a cluster of metabolic factors that increase the risk of cardiovascular disease and type 2 diabetes mellitus (T2DM), which is in itself a major cardiovascular disease risk factor. The aim of this review is to summarize the data related to the influence of the gut microbiota on the development of obesity and the MetS, highlighting the role of diet in controlling the MetS by modifying the gut microbiota. The main alterations in the gut microbiota of individuals with MetS consist of an increased Firmicutes/Bacteriodetes ratio and a reduced capacity to degrade carbohydrates to short-chain fatty acids, which in turn is related with the metabolic dysfunction of the host organism rather than with obesity itself. In addition to a low-fat, high-carbohydrate diet, with its high fiber intake, a diet with 30% fat content but with a high content in fruit and vegetables, such as the Mediterranean diet, is beneficial and partially restores the dysbiosis found in individuals with MetS. Overall, the shaping of the gut microbiota through the administration of prebiotics or probiotics increases the short-chain fatty acid production and is therefore a valid alternative in MetS treatment.

Gut Microbiota, Host Organism, and Diet Trialogue in Diabetes and Obesity

The gastrointestinal tract with its microbiota is a complex, open, and integrated ecosystem with a high environmental exposure. It is widely accepted that the healthy gut microbiotais essential for host homeostasis and immunostasis, harboring an enormous number and variety of microorganisms and genes tailored by hundreds of exogenous and intrinsic host factors. The occurrence of dysbiosis may contribute to host vulnerability and progression to a large spectrum of infectious and non-communicable diseases, including diabetes and obesity, two metabolic disorders that are showing an endemic trend nowadays. There is an urgent need to develop efficient strategies to prevent and treat metabolic disorders such as diabetes and obesity which are often associated with serious complications. In this paper, we give an overview on the implications of gut microbiota in diabesity, with a focus on the triangle gut microbiota—diet-host metabolism and on the way to manipulate the gut microbial ecosystem toward achieving novel diagnosis and predictive biomarkers with the final goal of reestablishing the healthy metabolic condition. The current research data regarding the precision/personalized nutrition suggest that dietary interventions, including administration of pre-, pro-, and syn-biotics, as well as antibiotic treatment should be individually tailored to prevent chronic diseases based on the genetic background, food and beverage consumption, nutrient intake, microbiome, metabolome, and other omic profiles.

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.

Effect of synbiotic pomegranate juice on glycemic, sex hormone profile and anthropometric indices in PCOS: A randomized, triple blind, controlled trial

BACKGROUND AND AIMS

Polycystic Ovarian Syndrome is a common reproductive, endocrine, and metabolic disease in women. Pomegranate juice, known as a rich source of phytochemicals with high antioxidant activity, enriched with probiotic may improve PCOS.

METHODS AND RESULTS

A randomized, controlled, triple-blinded, parallel trial study was performed in PCOS patients (n = 92). Three treatment groups (23 patients each) received 2 L of synbiotic pomegranate juice (SPJ), pomegranate juice (PJ), and synbiotic beverage (SB) weekly. The control group (23 patients) received 2 L of placebo beverage weekly. Primary outcome was any change in insulin resistance and secondary outcomes were fasting blood sugar (FBS), insulin sensitivity, testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH), body mass index (BMI), waist and hip circumference, from baseline to the end of the trial. At the end of the study, 86 patients were analyzed. There was significant change in insulin resistance in the SPJ and SB groups. Insulin sensitivity increased significantly in the SPJ and SB groups. Insulin also changed significantly in the SPJ and SB groups. BMI, weight and waist circumference decreased significantly in the SPJ and SB groups. Testosterone level also decreased significantly in the SPJ and SB groups. There was no significant change in FPG, LH and FSH in any of the groups.

CONCLUSION

SPJ in the form of a new beverage can improve insulin resistance, insulin, testosterone level, BMI, weight and waist circumference in PCOS. This trial was registered in Iranian Registry of Clinical Trials, with number: 25272.

Gut-Liver Axis, Gut Microbiota, and Its Modulation in the Management of Liver Diseases: A Review of the Literature

The rapid scientific interest in gut microbiota (GM) has coincided with a global increase in the prevalence of infectious and non-infectivous liver diseases. GM, which is also called “the new virtual metabolic organ”, makes axis with a number of extraintestinal organs, such as kidneys, brain, cardiovascular, and the bone system. The gut-liver axis has attracted greater attention in recent years. GM communication is bi-directional and involves endocrine and immunological mechanisms. In this way, gut-dysbiosis and composition of “ancient” microbiota could be linked to pathogenesis of numerous chronic liver diseases such as chronic hepatitis B (CHB), chronic hepatitis C (CHC), alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), development of liver cirrhosis, and hepatocellular carcinoma (HCC). In this paper, we discuss the current evidence supporting a GM role in the management of different chronic liver diseases and potential new therapeutic GM targets, like fecal transplantation, antibiotics, probiotics, prebiotics, and symbiotics. We conclude that population-level shifts in GM could play a regulatory role in the gut-liver axis and, consequently, etiopathogenesis of chronic liver diseases. This could have a positive impact on future therapeutic strategies.

Defective Autophagy in T Cells Impairs the Development of Diet-Induced Hepatic Steatosis and Atherosclerosis

Macroautophagy (or autophagy) is a conserved cellular process in which cytoplasmic cargo is targeted for lysosomal degradation. Autophagy is crucial for the functional integrity of different subsets of T cells in various developmental stages. Since atherosclerosis is an inflammatory disease of the vessel wall which is partly characterized by T cell mediated autoimmunity, we investigated how advanced atherosclerotic lesions develop in mice with T cells that lack autophagy-related protein 7 (Atg7), a protein required for functional autophagy. Mice with a T cell-specific knock-out of Atg7 (Lck-Cre Atg7^f/f) had a diminished naïve CD4⁺ and CD8⁺ T cell compartment in the spleen and mediastinal lymph node as compared to littermate controls (Atg7^f/f). Lck-Cre Atg7^f/f and Atg7^f/f mice were injected intravenously with rAAV2/8-D377Y-mPCSK9 and fed a Western-type diet to induce atherosclerosis. While Lck-Cre Atg7^f/f mice had equal serum Proprotein Convertase Subtilisin/Kexin type 9 levels as compared to Atg7^f/f mice, serum cholesterol levels were significantly diminished in Lck-Cre Atg7^f/f mice. Histological analysis of the liver revealed less steatosis, and liver gene expression profiling showed decreased expression of genes associated with hepatic steatosis in Lck-Cre Atg7^f/f mice as compared to Atg7^f/f mice. The level of hepatic CD4⁺ and CD8⁺ T cells was greatly diminished but both CD4⁺ and CD8⁺ T cells showed a relative increase in their IFNγ and IL-17 production upon Atg7 deficiency. Atg7 deficiency furthermore reduced the hepatic NKT cell population which was decreased to < 0.1% of the lymphocyte population. Interestingly, T cell-specific knock-out of Atg7 decreased the mean atherosclerotic lesion size in the tri-valve area by over 50%. Taken together, T cell-specific deficiency of Atg7 resulted in a decrease in hepatic steatosis and limited inflammatory potency in the (naïve) T cell compartment in peripheral lymphoid tissues, which was associated with a strong reduction in experimental atherosclerosis.

L-Fucose ameliorates high-fat diet-induced obesity and hepatic steatosis in mice

Background

l-Fucose (Fuc), a six-deoxy hexose monosaccharide, is present endogenously in humans and animals and has a wide range of biological functions. In the present study, we aimed to examine the effect of Fuc on obesity and hepatic steatosis in mice fed a high-fat diet (HFD).

Methods

C57BL/6 mice were fed a normal chow (NC) or HFD for 18 weeks to induce obesity and fatty liver. Fuc was administered intragastrically from the 8th week to the end of the experiment (18 weeks).

Results

Metagenomic analysis showed that HFD altered the genomic profile of gut microbiota in the mice; specifically, expression of alpha-l-fucosidase, the gene responsible for Fuc generation, was markedly reduced in the HFD group compared with that in the NC group. Fuc treatment decreased body weight gain, fat accumulation, and hepatic triglyceride elevation in HFD-fed mice. In addition, Fuc decreased the levels of endotoxin-producing bacteria of the Desulfovibrionaceae family and restored HFD-induced enteric dysbiosis at both compositional and functional levels.

Conclusion

Our findings suggest that Fuc might be a novel strategy to treat HFD-induced obesity and fatty liver.

Biological Activities of Lactose-Based Prebiotics and Symbiosis with Probiotics on Controlling Osteoporosis, Blood-Lipid and Glucose Levels

Lactose-based prebiotics are synthesized by enzymatic- or microbial- biotransformation of lactose and have unique functional values. In this comprehensive review article, the biochemical mechanisms of controlling osteoporosis, blood-lipid, and glucose levels by lactose-based prebiotics and symbiosis with probiotics are reported along with the results of clinical investigations. Interaction between lactose-based prebiotics and probiotics reduces osteoporosis by (a) transforming insoluble inorganic salts to soluble and increasing their absorption to gut wall; (b) maintaining and protecting mineral absorption surface in the intestine; (c) increasing the expression of calcium-binding proteins in the gut wall; (d) remodeling osteoclasts and osteoblasts formation; (e) releasing bone modulating factors; and (f) degrading mineral complexing phytic acid. Lactose-based prebiotics with probiotics control lipid level in the bloodstream and tissue by (a) suppressing the expressions of lipogenic- genes and enzymes; (b) oxidizing fatty acids in muscle, liver, and adipose tissue; (c) binding cholesterol with cell membrane of probiotics and subsequent assimilation by probiotics; (d) enzymatic-transformations of bile acids; and (e) converting cholesterol to coprostanol and its defecation. Symbiosis of lactose-based prebiotics with probiotics affect plasma glucose level by (a) increasing the synthesis of gut hormones plasma peptide-YY, glucagon-like peptide-1 and glucagon-like peptide-2 from entero-endocrine L-cells; (b) altering glucose assimilation and metabolism; (c) suppressing systematic inflammation; (d) reducing oxidative stress; and (e) producing amino acids. Clinical investigations show that lactose-based prebiotic galacto-oligosaccharide improves mineral absorption and reduces hyperlipidemia. Another lactose-based prebiotic, lactulose, improves mineral absorption, and reduces hyperlipidemia and hyperglycemia. It is expected that this review article will be of benefit to food technologists and medical practitioners.

Activation of natural killer T cells contributes to triptolide-induced liver injury in mice

Triptolide (TP) is the main active ingredient of Tripterygium wilfordii Hook.f, which has attracted great interest due to its promising efficacy for autoimmune diseases and tumors. However, severe adverse reactions, especially hepatotoxicity, have restricted its approval in the market. In the present study we explored the role of hepatic natural killer T (NKT) cells in the pathogenesis of TP-induced liver injury in mice. TP (600 μg/kg/day, i.g.) was administered to female mice for 1, 3, or 5 days. We found that administration of TP dose-dependently induced hepatotoxicity, evidenced by the body weight reduction, elevated serum ALT and AST levels, as well as significant histopathological changes in the livers. However, the mice were resistant to the development of TP-induced liver injury when their NKT cells were depleted by injection of anti-NK1.1 mAb (200 μg, i.p.) on days -2 and -1 before TP administration. We further revealed that TP administration activated NKT cells, dominantly releasing Th1 cytokine IFN-γ, recruiting neutrophils and macrophages, and leading to liver damage. After anti-NK1.1 injection, however, the mice mainly secreted Th2 cytokine IL-4 in the livers and exhibited a significantly lower percentage of hepatic infiltrating neutrophils and macrophages upon TP challenge. The activation of NKT cells was associated with the upregulation of Toll-like receptor (TLR) signaling pathway. Collectively, these results demonstrate a novel role of NKT cells contributing to the mechanisms of TP-induced liver injury. More importantly, the regulation of NKT cells may promote effective measures that control drug-induced liver injury.

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.

Probiotics improve gut microbiota dysbiosis in obese mice fed a high-fat or high-sucrose diet

OBJECTIVE

Gut microbiota plays a crucial role in host energy homeostasis, which is affected by both high-fat diets (HFDs) and high-sucrose diets (HCDs). Probiotics treatment can effectively modulate intestinal microbiota. However, it remains unclear whether probiotics can effectively improve HFD- and HCD-induced microbiota dysbiosis.

METHODS

Mice were fed either an HFD, HCD, or normal diet for 13 wk and administered probiotics during the last 4 wk of the diet. Fecal and cecal samples were collected and analyzed by high-throughput 16S ribosomal RNA sequencing.

RESULTS

Body weight increased more in the HFD group compared with the HCD group. Probiotics supplementation slowed weight gain in both the HFD and HCD groups. Both the HFD and HCD reduced microbial diversity, abundance of butyric acid-producing bacteria, and some other beneficial bacteria, including Lactobacillus, Clostridium sensu stricto, Prevotella, and Alloprevotella, but increased conditional pathogenic bacteria, such as Bacteroides, Alistipes, and Anaerotruncus. Probiotics markedly restored the proportions of bacteria affected in the HFD and HCD groups and increased the abundance of microbiota negatively associated with obesity, including Bifidobacterium, Lactococcus, and Akkermansia. In addition, Oscillibacter, Escherichia/Shigella, Acinetobacter, and Blautia significantly increased in the HCD group; Allobaculum, Olsenella, and Ruminococcus were significantly changed in the HFD group. HCD-induced microbiota dysbiosis was more susceptible to probiotics treatment compared with the HFD.

CONCLUSIONS

Probiotics treatment can mitigate diet-induced obesity partly through modulating intestinal microbiota, especially in HCD-induced obesity.

Bifidobacteria attenuate the development of metabolic disorders, with inter- and intra-species differences

Host gut microbiota dysbiosis occurs for multiple reasons and is often accompanied by chronic inflammation induced by a high-fat-high-sucrose (HFHS) diet and related metabolic disorders. Intervention with probiotics is a novel strategy for amelioration of metabolic syndrome, which is believed to regulate the gut microbiota composition to some extent. We investigated the relationship amongst bifidobacteria treatment, HFHS diet-induced metabolic disorders and the gut microbiota composition. Seven strains of bifidobacteria from four species were individually administered to rats fed a HFHS diet for 12 weeks. Various bifidobacteria strains showed various effects on the recovery of metabolic disorders and gut microbiota dysbiosis, and these effects seemed to be inter- or intra-species specific. Bifidobacterium longum, B. adolescentis and B. bifidum seemed to affect the blood glucose balance, whilst two strains of B. breve showed extremely different effects in this area. However, only one strain of B. longum and the B. adolescentis displayed significant regulation of blood lipid levels. The protective effects of bifidobacteria on the pancreas were strongly correlated with those on blood glucose. Furthermore, the influence of bifidobacteria on gut microbiota dysbiosis also showed a potential relationship with symptoms of metabolic disorders. Of these seven strains, B. adolescentis Z25 displayed an outstanding ability to alleviate metabolic syndrome, including glucose and lipid metabolism disorders, tissue damage and gut microbiota dysbiosis. This strain, coupled with other prebiotics and probiotics, could be used as a potential treatment approach for metabolic syndrome induced by a HFHS diet.

Mechanistic and therapeutic advances in non-alcoholic fatty liver disease by targeting the gut microbiota

Non-alcoholic fatty liver disease (NAFLD) is one of the most common metabolic diseases currently in the context of obesity worldwide, which contains a spectrum of chronic liver diseases, including hepatic steatosis, non-alcoholic steatohepatitis and hepatic carcinoma. In addition to the classical "Two-hit" theory, NAFLD has been recognized as a typical gut microbiota-related disease because of the intricate role of gut microbiota in maintaining human health and disease formation. Moreover, gut microbiota is even regarded as a "metabolic organ" that play complementary roles to that of liver in many aspects. The mechanisms underlying gut microbiota-mediated development of NAFLD include modulation of host energy metabolism, insulin sensitivity, and bile acid and choline metabolism. As a result, gut microbiota have been emerging as a novel therapeutic target for NAFLD by manipulating it in various ways, including probiotics, prebiotics, synbiotics, antibiotics, fecal microbiota transplantation, and herbal components. In this review, we summarized the most recent advances in gut microbiota-mediated mechanisms, as well as gut microbiota-targeted therapies on NAFLD.

Probiotics and Their Potential Preventive and Therapeutic Role for Cancer, High Serum Cholesterol, and Allergic and HIV Diseases

The potential health benefits of probiotics have long been elucidated since Metchnikoff and his coworkers postulated the association of probiotic consumption on human's health and longevity. Since then, many scientific findings and research have further established the correlation of probiotic and gut-associated diseases such as irritable bowel disease and chronic and antibiotic-associated diarrhea. However, the beneficial impact of probiotic is not limited to the gut-associated diseases alone, but also in different acute and chronic infectious diseases. This is due to the fact that probiotics are able to modify the intestinal microbial ecosystem, enhance the gut barrier function, provide competitive adherence to the mucosa and epithelium, produce antimicrobial substances, and modulate the immune activity by enhancing the innate and adaptive immune response. Nevertheless, the current literature with respect to the association of probiotic and cancer, high serum cholesterol, and allergic and HIV diseases are still scarce and controversial. Therefore, in the present work, we reviewed the potential preventive and therapeutic role of probiotics for cancer, high serum cholesterol, and allergic and HIV diseases as well as providing its possible mechanism of actions.

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.

Adipose tissue inflammation and metabolic syndrome. The proactive role of probiotics

PURPOSE

The first part of this review focuses on the role of cells and molecules of adipose tissue involved in metabolic syndrome-induced inflammation and in the maintenance of this pathology. In the second part of the review, the potential role of probiotics-modulating metabolic syndrome-related inflammatory components is summarized and discussed.

METHODS

The search for the current scientific literature was carried out using ScienceDirect, PubMed, and Google Scholar search engines. The keywords used were: metabolic syndrome, obesity, insulin resistant, adipose tissue, adipose tissue inflammation, chronic low-grade inflammation, immune cells, adipokines, cytokines, probiotics, and gut microbiota.

RESULTS AND CONCLUSIONS

Chronic low-grade inflammation that characterized metabolic syndrome can contribute to the development of the metabolic dysfunctions involved in the pathogenesis of its comorbidities. Adipose tissue is a complex organ that performs metabolic and immune functions. During metabolic syndrome, an imbalance in the inflammatory components of adipose tissue (immune cells, cytokines, and adipocytokines), which shift from an anti-inflammatory to a pro-inflammatory profile, can provoke metabolic syndrome linked complications. Further knowledge concerning the immune function of adipose tissue may contribute to finding better alternatives for the treatment or prevention of such disorders. The control of inflammation could result in the management of many of the pathologies related to metabolic syndrome. Due to the strong evidence that gut microbiota composition plays a role modulating the body weight, adipose tissue, and the prevalence of a low-grade inflammatory status, probiotics emerge as valuable tools for the prevention of metabolic syndrome and health recovery.

Conjugated linoleic acid enriched skim milk prepared with Lactobacillus fermentum DDHI27 endorsed antiobesity in mice

Aim: This study evaluated the antiobesity effect of skim milk prepared with conjugated linoleic acid producing probiotic Lactobacillus fermentum DDHI27 (PCLA). Materials & methods: C57BL/6 J mice were divided into five groups, and different obesity-associated parameters were studied. Results: PCLA supplementation alleviated body weight, epididymal and mesenteric fats and improves lipid profiles. Significant ameliorations in leptin, blood glucose, hepatic steatosis and reduction in adipocytes size were also observed. Additionally, feeding also led to positive alterations in the adipogenesis transcription factors and key lipogenesis genes. Improvement in the gut microbiota dysbiosis was also revealed. Conclusion: Results inferred that PCLA exerted an antiobesity effect in diet-induced obese mice and may be further developed in the functional foods for the management of obesity.

The Role of the Gut Microbiome in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease, with prevalence increasing in parallel with the rising incidence in obesity. Believed to be a "multiple-hit" disease, several factors contribute to NAFLD initiation and progression. Of these, the gut microbiome is gaining interest as a significant factor in NAFLD prevalence. In this paper, we provide an in-depth review of the progression of NAFLD, discussing the mechanistic modes of hepatocyte injury and the potential role for manipulation of the gut microbiome as a therapeutic strategy in the prevention and treatment of NAFLD.

Environmental Sources of Bacteria Differentially Influence Host-Associated Microbial Dynamics

These results provide valuable insights into the ecological influence of exogenous microbial exposure, as well as laying the foundation for improving aquarium management practices. By comparing data for dolphins from aquaria that use natural versus artificial seawater, we demonstrate the potential influence of aquarium water disinfection procedures on dolphin microbial dynamics.

Host-associated microbial dynamics are influenced by dietary and immune factors, but how exogenous microbial exposure shapes host-microbe dynamics remains poorly characterized. To investigate this phenomenon, we characterized the skin, rectum, and respiratory tract-associated microbiota in four aquarium-housed dolphins daily over a period of 6 weeks, including administration of a probiotic during weeks 4 to 6. The environmental bacterial sources were also characterized, including the animals’ human handlers, the aquarium air and water, and the dolphins’ food supply. Continuous microbial exposure occurred between all sites, yet each environment maintained a characteristic microbiota, suggesting that the majority of exposure events do not result in colonization. Small changes in water physicochemistry had a significant but weak correlation with change in dolphin-associated bacterial richness but had no influence on phylogenetic diversity. Food and air microbiota were the richest and had the largest conditional influence on other microbiota in the absence of probiotics, but during probiotic administration, food alone had the largest influence on the stability of the dolphin microbiota. Our results suggest that respiratory tract and gastrointestinal epithelium interactions with air- and food-associated microbes had the biggest influence on host-microbiota dynamics, while other interactions, such as skin transmission, played only a minor role. Finally, direct oral stimulation with a foreign exogenous microbial source can have a profound effect on microbial stability.

IMPORTANCE These results provide valuable insights into the ecological influence of exogenous microbial exposure, as well as laying the foundation for improving aquarium management practices. By comparing data for dolphins from aquaria that use natural versus artificial seawater, we demonstrate the potential influence of aquarium water disinfection procedures on dolphin microbial dynamics.

Role of gut microbiota and oxidative stress in the progression of non-alcoholic fatty liver disease to hepatocarcinoma: Current and innovative therapeutic approaches

Non-alcoholic fatty liver disease (NAFLD) represents the most common chronic liver disease in industrialized countries. NAFLD progresses through the inflammatory phase of non-alcoholic steatohepatitis (NASH) to fibrosis and cirrhosis, with some cases developing liver failure or hepatocellular carcinoma (HCC). Liver biopsy remains the gold standard approach to a definitive diagnosis of NAFLD and the distinction between simple steatosis and NASH. The pathogenesis of NASH is still not clear. Several theories have been proposed ranging from the "Two Hit Theory" to the "Multiple Hit Theory". However, the general consensus is that the gut microbiota, oxidative stress, and mitochondrial damage play key roles in the pathogenesis of NASH. The interaction between the gut epithelia and some commensal bacteria induces the rapid generation of reactive oxygen species (ROS). The main goal of any therapy addressing NASH is to reverse or prevent progression to liver fibrosis/cirrhosis. This problem represents the first "Achilles' heel" of the new molecules being evaluated in most ongoing clinical trials. The second is the inability of these molecules to reach the mitochondria, the primary sites of energy production and ROS generation. Recently, a variety of non-pharmacological and pharmacological treatment approaches for NASH have been evaluated including vitamin E, the thiazolidinediones, and novel molecules related to NASH pathogenesis (including obeticholic acid and elafibranor). Recently, a new isoform of human manganese superoxide dismutase (MnSOD) was isolated and obtained in a synthetic recombinant form designated rMnSOD. This protein has been shown to be a powerful antioxidant capable of mediating ROS dismutation, penetrating biological barriers via its uncleaved leader peptide, and reducing portal hypertension and fibrosis in rats affected by liver cirrhosis. Based on these distinctive characteristics, it can be hypothesized that this novel recombinant protein (rMnSOD) potentially represents a new and highly efficient adjuvant therapy to counteract the progression from NASH to HCC.

Lactobacillus acidophilus NS1 attenuates diet-induced obesity and fatty liver

Obesity is a major threat to public health, and it is strongly associated with insulin resistance and fatty liver disease. Here, we demonstrated that administration of Lactobacillus acidophilus NS1 (LNS1) significantly reduced obesity and hepatic lipid accumulation, with a concomitant improvement in insulin sensitivity, in high-fat diet (HFD)-fed mice. Furthermore, administration of LNS1 inhibited the effect of HFD feeding on the SREBP-1c and PPARα signaling pathways and reduced lipogenesis with an increase in fatty acid oxidation in ex vivo livers from HFD-fed mice. These LNS1 effects were confirmed in HepG2 cells and ex vivo livers by treatment with LNS1 culture supernatant (LNS1-CS). Interestingly, AMPK phosphorylation and activity in the liver of HFD-fed mice were increased by administration of LNS1. Consistently, chemical inhibition of AMPK with compound C, a specific inhibitor of AMPK, dramatically reduced the effect of LNS1-CS on lipid metabolism in HepG2 cells and ex vivo livers by modulating the SREBP-1c and PPARα signaling pathways. Furthermore, administration of LNS1 to HFD-fed mice significantly improved insulin resistance and increased Akt phosphorylation in the liver, white adipose tissue and skeletal muscle. Together, these data suggest that LNS1 may prevent diet-induced obesity and related metabolic disorders by improving lipid metabolism and insulin sensitivity through an AMPK→SREBP-1c/PPARα signaling pathway.

The Effects of Synbiotic Supplementation on Body Mass Index, Metabolic and Inflammatory Biomarkers, and Appetite in Patients with Metabolic Syndrome: A Triple-Blind Randomized Controlled Trial

It has been shown recently that metabolic syndrome is associated with gut dysbiosis. The gut microbiota may be the main target for prevention or treatment of metabolic syndrome. We investigated the effects of synbiotic supplementation on metabolic syndrome. In this triple-blinded clinical trial, 46 Iranian patients with metabolic syndrome, from both sexes, aged 25-70 years, who fulfilled inclusion criteria were randomly categorized to receive either the synbiotic or a placebo capsule, twice a day for three months, plus a weight-loss diet using stratified random sampling based on body mass index (BMI). Each synbiotic capsule consisted of seven strains probiotic bacteria (2× 10⁸) plus fructooligosaccharide as a prebiotic. Anthropometric measurements and biochemical tests were assessed at baseline and at the end of week 12 for fasting blood sugar (FBS), insulin, lipid profile, high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), peptide YY (PYY), and glucagon-like peptide-1 (GLP-1). The mean changes of weight, BMI, FBS, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), and GLP-1 between the two groups was statistically significant (p < .001). Furthermore, peptide YY (PYY) increased significantly in the synbiotic group (p ≤ .05). The trend of weight loss in the synbiotic group was significant until the end of the study (p < .001) while it stopped at week 6 in the placebo group. Synbiotic treatment may improve the status of BMI, FBS, insulin resistance, HOMA-IR, GLP-1, and PYY in patients with metabolic syndrome.

Microbiota, Liver Diseases, and Alcohol

Being overweight and obesity are the leading causes of liver disease in Western countries. Liver damage induced by being overweight can range from steatosis, harmless in its simple form, to steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. Alcohol consumption is an additional major cause of liver disease. Not all individuals who are overweight or excessively consume alcohol develop nonalcoholic fatty liver diseases (NAFLD) or alcoholic liver disease (ALD) and advanced liver disease. The role of the intestinal microbiota (IM) in the susceptibility to liver disease in this context has been the subject of recent studies. ALD and NAFLD appear to be influenced by the composition of the IM, and dysbiosis is associated with ALD and NAFLD in rodent models and human patient cohorts. Several microbial metabolites, such as short-chain fatty acids and bile acids, are specifically associated with dysbiosis. Recent studies have highlighted the causal role of the IM in the development of liver diseases, and the use of probiotics or prebiotics improves some parameters associated with liver disease. Several studies have made progress in deciphering the mechanisms associated with the modulation of the IM. These data have demonstrated the intimate relationship between the IM and metabolic liver disease, suggesting that targeting the gut microbiota could be a new preventive or therapeutic strategy for these diseases.

The role of intestinal microbiota in the pathogenesis of NAFLD: starting points for intervention

In recent years, close links between intestinal microbiota and host metabolism have been recognized. Intestinal bacteria can participate in the extraction of calories from food, and circulation of bacterial products, in particular lipopolysaccharides (LPS), is responsible for the "metabolic endotoxemia", which contributes to insulin resistance and its complications, such as non-alcoholic fatty liver disease (NAFLD). Indeed, qualitative and quantitative intestinal dysbiotic changes have been clearly documented in NAFLD patients, and several mechanisms by which the intestinal microbiota can directly promote liver fat deposition, inflammation and fibrosis have also been described. Consistently, although with some differences concerning type and proportion of results, experimental and clinical studies are quite concordant in demonstrating beneficial effects of probiotic and/or prebiotic therapy in NAFLD. Although some physiopathological bases have been produced, major doubts still remain concerning how and when to intervene. Indeed, most of the available works were performed with mixtures of probiotics and/or prebiotics, and a baseline assessment of dysbiosis aimed at selecting the best candidates for treatment and predicting response has not been performed in any of the clinical studies in NAFLD. While future research is expected to solve these issues, the particularly favorable safety profile suggests that probiotic/prebiotic therapy could already be "tested" in NAFLD patients on an individual basis, at least once all the measures recommended by the latest guidelines have failed.

Lipopolysaccharide increases the release of VEGF-C that enhances cell motility and promotes lymphangiogenesis and lymphatic metastasis through the TLR4- NF-κB/JNK pathways in colorectal cancer

Lipopolysaccharide (LPS) exists in the outer membrane of Gram-negative bacteria. Colorectal normal epithelium and colorectal cancer cells in situ are continuously exposed to LPS from intestinal bacteria, while little is known about the influence of LPS on colorectal cancer progression and metastasis. In this study, we investigated the potential role of LPS on colorectal cancer progression and metastasis as well as the underlying mechanisms. We measured higher LPS concentration in colorectal cancer tissues and even higher LPS concentration in colorectal cancer tissues with lymph node metastasis. LPS significantly enhanced cancer cell motility and promoted human dermal lymphatic endothelial cells' (HDLECs') capacity of tube-like formation in vitro, as well as accelerates lymphangiogenesis and lymph node metastasis in nude mice. Furthermore, we demonstrated LPS notably increased the expression of VEGF-C in a time-dependent and concentration-dependent manner. VEGF-C is a key regulator for lymphangiogenesis and lymph node metastasis. By constructing lentivirus-mediated shVEGF-C cells, VEGF-C down-regulation suppressed LPS' promotive effect on cancer cell motility and HDLEC tube-like formation capacity. In addition, we found TLR4- NF-κB/JNK signal pathways were important for LPS to increase VEGF-C expression. All these result suggested a critical role for LPS in migration, invasion, lymphangiogenesis and lymph node metastasis of colorectal cancer, providing evidence that LPS increased VEGF-C secretion to promote cell motility and lymphangiogenesis via TLR4- NF-κB/JNK signaling.

The beneficial effects of probiotic administration on wound healing and metabolic status in patients with diabetic foot ulcer: A randomized, double-blind, placebo-controlled trial

BACKGROUND

This study was conducted to evaluate the effects of probiotic supplementation on wound healing and metabolic status in subjects with diabetic foot ulcer (DFU).

METHODS

This randomized, double-blind, placebo-controlled trial was conducted among 60 subjects (aged 40-85 years old) with grade 3 diabetic foot ulcer. Individuals were randomly divided into 2 groups (30 subjects each group) to receive either probiotic or placebo daily for 12 weeks.

RESULTS

After the 12-week intervention, compared with the placebo, probiotic supplementation led to significant reductions in ulcer length (-1.3 ± 0.9 vs. -0.8 ± 0.7 cm, P = .01), width (-1.1 ± 0.7 vs. -0.7 ± 0.7 cm, P = .02), and depth (-0.5 ± 0.3 vs. -0.3 ± 0.3 cm, P = .02). Furthermore, significant reductions in fasting plasma glucose (-29.6 ± 30.3 vs. -5.8 ± 39.8 mg/dL, P = .01), serum insulin concentrations (-4.3 ± 7.9 vs. +0.4 ± 8.5 μIU/mL, P = .03), and haemoglobin A1c (-0.6 ± 0.5 vs. -0.2 ± 0.4%, P = .003) and a significant rise in the quantitative insulin sensitivity check index (+0.01 ± 0.01 vs. -0.01 ± 0.02, P = .003) were seen following supplementation of probiotic compared with the placebo. Additionally, compared with the placebo, probiotic supplementation resulted in significant decreases in serum total cholesterol (-4.8 ± 16.1 vs. +7.0 ± 27.1 mg/dL, P = .04), high-sensitivity C-reactive protein (-9.0 ± 14.7 vs. -1.7 ± 8.6 mg/L, P = .02), plasma malondialdehyde (-0.8 ± 0.8 vs. -0.2 ± 0.8 μmol/L, P = .001), and significant increases in plasma nitric oxide (+6.2 ± 8.2 vs. +0.8 ± 8.0 μmol/L, P = .01) and total antioxidant capacity concentrations (+179.3 ± 97.2 vs. -85.1 ± 203.4 mmol/L, P < .001).

CONCLUSIONS

Overall, probiotic supplementation for 12 weeks among subjects with diabetic foot ulcer had beneficial effects on ulcer size, glycaemic control, total cholesterol, high-sensitivity C-reactive protein, plasma nitric oxide, total antioxidant capacity, and malondialdehyde levels.

Cafeteria diet and probiotic therapy: cross talk among memory, neuroplasticity, serotonin receptors and gut microbiota in the rat

The western diet is known to have detrimental effects on cognition and the gut microbiota, but few studies have investigated how these may be related. Here, we examined whether a probiotic could prevent diet-induced memory deficits. Rats were pre-exposed to vehicle, low or high doses of VSL#3 for 2 weeks before half were switched from chow to a cafeteria diet (Caf) for 25 days; VSL#3 treatment continued until death. High-dose VSL#3 prevented the diet-induced memory deficits on the hippocampal-dependent place task, but the probiotic caused deficits on the perirhinal-dependent object task, irrespective of diet or dose. No differences were observed in anxiety-like behaviour on the elevated plus maze. Gut microbial diversity was dramatically decreased by Caf diet and here, VSL#3 was able to increase the abundance of some taxa contained in the probiotic such as Streptococcus and Lactobacillus and also other taxa including Butyrivibrio, which were decreased by the Caf diet. This affected the predicted profile of microbial metabolic pathways related to antioxidant and bile biosynthesis, and fat and carbohydrate metabolism. In the hippocampus, the Caf diet increased the expression of many genes related to neuroplasticity and serotonin receptor (5HT) 1A, which was normalised in Caf-High rats. Distance-based linear modelling showed that these genes were the best predictors of place memory, and related to microbiota principal component (PC) 1. Neuroplasticity genes in the perirhinal cortex were also affected and related to PC1 but object memory performance was correlated with perirhinal 5HT2C expression and microbiota PC3. These results show that probiotics can be beneficial in situations of gut dysbiosis where memory deficits are evident but may be detrimental in healthy subjects.

The effects of probiotic supplementation on metabolic status in type 2 diabetic patients with coronary heart disease

BACKGROUND

This study was conducted to evaluate the effects of probiotic supplementation on metabolic profiles in diabetic patients with coronary heart disease (CHD).

METHODS

This randomized, double-blind, placebo-controlled trial was performed among 60 diabetic patients with CHD, aged 40-85 years at a cardiology clinic in Kashan, Iran, from October 2017 through January 2018. Patients were randomly divided into two groups to take either probiotic supplements (n = 30) or placebo (n = 30) for 12 weeks. Fasting blood samples were taken at the beginning of the study and after the 12-week intervention to determine related markers.

RESULTS

After 12-week intervention, probiotic supplementation significantly decreased fasting plasma glucose (β - 20.02 mg/dL; 95% CI - 33.86, - 6.17; P = 0.005), insulin (β - 2.09 µIU/mL; 95% CI - 3.77, - 0.41; P = 0.01), insulin resistance (β - 0.50; 95% CI - 0.96, - 0.03; P = 0.03) and total-/HDL-cholesterol ratio (β - 0.27; 95% CI - 0.52, - 0.03; P = 0.02), and significantly increased insulin sensitivity (β 0.008; 95% CI 0.001, 0.01; P = 0.02) and HDL-cholesterol levels (β 2.52 mg/dL; 95% CI 0.04, 5.00; P = 0.04) compared with the placebo. Moreover, probiotic supplementation led to a significant reduction in serum high sensitivity C-reactive protein (β - 0.88 mg/L; 95% CI - 1.39, - 0.38; P = 0.001), and a significant elevation in total antioxidant capacity (β 108.44 mmol/L; 95% CI 47.61, 169.27; P = 0.001) and total glutathione levels (β 45.15 µmol/L; 95% CI 5.82, 84.47; P = 0.02) compared with the placebo. Probiotic supplementation did not affect other metabolic profiles.

CONCLUSIONS

Overall, we found that probiotic supplementation for 12 weeks had beneficial effects on glycemic control, HDL-cholesterol, total-/HDL-cholesterol ratio, biomarkers of inflammation and oxidative stress in diabetic patients with CHD.Trial registration Clinical trial registration number http://www.irct.ir: IRCT2017082733941N5.

Microbial Regulation of Glucose Metabolism and Insulin Resistance

Type 2 diabetes is a combined disease, resulting from a hyperglycemia and peripheral and hepatic insulin resistance. Recent data suggest that the gut microbiota is involved in diabetes development, altering metabolic processes including glucose and fatty acid metabolism. Thus, type 2 diabetes patients show a microbial dysbiosis, with reduced butyrate-producing bacteria and elevated potential pathogens compared to metabolically healthy individuals. Furthermore, probiotics are a known tool to modulate the microbiota, having a therapeutic potential. Current literature will be discussed to elucidate the complex interaction of gut microbiota, intestinal permeability and inflammation leading to peripheral and hepatic insulin resistance. Therefore, this review aims to generate a deeper understanding of the underlying mechanism of potential microbial strains, which can be used as probiotics.

Comparative study of probiotic effects of Lactobacillus and Bifidobacteria strains on cholesterol levels, liver morphology and the gut microbiota in obese mice

BACKGROUND

Microbiome-modulating interventions are promising for treatment and prevention of metabolic syndrome. The number of probiotic strains demonstrated ability to decrease cholesterol level in vivo, however, it was poorly confirmed in a clinical setting. The aim was to study the effects of L. acidophilus IMV B-7279, L. casei IMV B-7280, B. animalіs VKL and B. animalіs VKB separately and in various compositions on the level of serum cholesterol, gut microbiota contents and liver morphology on a high-calorie-induced obesity model in BALB/c mice.

MATERIALS AND METHODS

We used for the study female BALB/c mice 6-8 weeks old (18-24 g). Experimental animals were fed by a fat-enriched diet (FED), and 8 experimental groups were formed (12 mice in each group) to test strains of probiotic bacteria L. delbrueckii subsp. bulgaricus IMV B-7281, L. casei IMV B-7280, B. animalіs VKL and B. animalіs VKB and compositions. We used ultrasound for in vivo assessment of the liver and visceral (mesenteric) fat size. In the blood serum of the obese mice, the level of cholesterol was estimated. The liver morphology and gut microbiota of obese mice were studied.

RESULTS

We revealed that after treatment with all of the studied probiotic bacteria and compositions of B. animalis VKL/B. animalis VKB/L. casei IMV B-7280, the weight of obese mice decreased, and cholesterol and its fraction levels in serum were reduced. The size of the liver slightly decreased after treatment with L. delbrueckii subsp. bulgaricus IMV B-7281, B. аnimalis VKB or probiotic compositions; we observed reduction of the mesenteric fat size after injection of all these probiotic bacteria (separately) and probiotic compositions. We defined the strain-dependent effects on serum lipid profiles, liver morphology and the gut microbiota. The B. animalis VKL/B. animalis VKB/L. casei IMV B-7280 composition effectively recovered the liver morphological structure of obese mice. The number of Lactobacillus spp., Bifidobacterium spp. and coliform bacteria increased, the number of staphylococci and streptococci reduced, and the number of microscopic fungi significantly decreased in the gut of obese mice after treatment with L. casei IMV B-7280, L. delbrueckii subsp. bulgaricus IMV B-7281, B. animalis (separately) or their compositions.

CONCLUSION

L. casei IMV B-7280 (separately) and a composition of B. animalis VKL/B. animalis VKB/L. casei IMV B-7280 are effective at decreasing the weight of obese mice, decreasing cholesterol level, restoring the liver morphology and beneficially modulating the gut microbiome in high-calorie-induced obesity.

Gut Microbiota and Nonalcoholic Fatty Liver Disease: Insights on Mechanisms and Therapy

The gut microbiota plays critical roles in development of obese-related metabolic diseases such as nonalcoholic fatty liver disease (NAFLD), type 2 diabetes(T2D), and insulin resistance(IR), highlighting the potential of gut microbiota-targeted therapies in these diseases. There are various ways that gut microbiota can be manipulated, including through use of probiotics, prebiotics, synbiotics, antibiotics, and some active components from herbal medicines. In this review, we review the main roles of gut microbiota in mediating the development of NAFLD, and the advances in gut microbiota-targeted therapies for NAFLD in both the experimental and clinical studies, as well as the conclusions on the prospect of gut microbiota-targeted therapies in the future.

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.

iNKT cells prevent obesity-induced hepatic steatosis in mice in a C-C chemokine receptor 7-dependent manner

Non-alcoholic fatty liver disease and non-alcoholic steatohepatitis are characterized by an increase in hepatic triglyceride content with infiltration of immune cells, which can cause steatohepatitis and hepatic insulin resistance. C-C chemokine receptor 7 (CCR7) is primarily expressed in immune cells, and CCR7 deficiency leads to the development of multi-organ autoimmunity, chronic renal disease and autoimmune diabetes. Here, we investigated the effect of CCR7 on hepatic steatosis in a mouse model and its underlying mechanism. Our results demonstrated that body and liver weights were higher in the CCR7^−/− mice than in the wild-type (WT) mice when they were fed a high-fat diet. Further, glucose tolerance and insulin sensitivity were markedly diminished in CCR7^−/− mice. The number of invariant natural killer T (iNKT) cells was reduced in the livers of the CCR7^−/− mice. Moreover, liver inflammation was detected in obese CCR7^−/− mice, which was ameliorated by the adoptive transfer of hepatic mononuclear cells from WT mice, but not through the transfer of hepatic mononuclear cells from CD1d^−/− or interleukin-10-deficient (IL-10^−/−) mice. Overall, these results suggest that CCR7⁺ mononuclear cells in the liver could regulate obesity-induced hepatic steatosis via induction of IL-10-expressing iNKT cells.

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

Galectin-9: Diverse roles in hepatic immune homeostasis and inflammation

Glycan-binding proteins, which include galectins, are involved at all stages of immunity and inflammation, from initiation through resolution. Galectin-9 (Gal-9) is highly expressed in the liver and has a wide variety of biological functions in innate and adaptive immunity that are instrumental in the maintenance of hepatic homeostasis. In the setting of viral hepatitis, increased expression of Gal-9 drives the expansion of regulatory T cells and contraction of effector T cells, thereby favoring viral persistence. The dichotomous nature of Gal-9 is evident in hepatocellular carcinoma, where loss of expression in hepatocytes promotes tumor growth and metastasis, whereas overexpression by Kupffer cells and endothelial cells inhibits the antitumor immune response. In nonalcoholic fatty liver disease, Gal-9 is involved indirectly in the expansion of protective natural killer T-cell populations. In ischemic liver injury, hepatocyte-derived Gal-9 is both diagnostic and cytoprotective. In drug-induced acute liver failure, plasma levels correlate with outcome. Here, we offer a synthesis of recent and emerging findings on Gal-9 in the regulation of hepatic inflammation. Ongoing studies are warranted to better elucidate the pathophysiology of hepatic immune-mediated diseases and to develop new therapeutic interventions using glycan-binding proteins. (Hepatology 2017;66:271-279).

Significant positive association of endotoxemia with histological severity in 237 patients with non-alcoholic fatty liver disease

BACKGROUND

Patients with nonalcoholic steatohepatitis (NASH) have gut dysbiosis and intestinal bacterial overgrowth.

AIM

To test the hypothesis that endotoxemia is associated with the histological severity of nonalcoholic fatty liver disease (NAFLD) and determine factors associated with endotoxemia.

METHODS

The endotoxemia markers lipopolysaccharide-binding protein (LBP) and endotoxin levels were measured in 237 NAFLD patients 1 day before liver biopsy. Biomarkers of liver injury and transient elastography were performed as additional markers of disease severity.

RESULTS

A total of 114/237 (48%) patients had NASH and 80/237 (34%) had F2-4 fibrosis. LBP was correlated with lobular inflammation (P=.001), while both LBP (P=.0004) and endotoxin levels (P=0.008) were correlated with fibrosis. LBP was also correlated with cytokeratin-18 fragments (P=.002) and aspartate aminotransferase-to-alanine aminotransferase ratio (P=.006), and both LBP (P=.019) and endotoxin (P=.006) were correlated with liver stiffness measurement by transient elastography. LBP was increased in patients with NASH (15.3±4.6 vs 13.8±3.3 μg/mL; P=.005) and F2-4 fibrosis (15.4±4.4 vs 14.0±3.7 μg/mL; P=.008). Interestingly, patients harbouring the TM6SF2 rs58542926 T allele that predispose to NAFLD/NASH had higher LBP level. By multivariate analysis, gender, higher body mass index and glycated haemoglobin, and TM6SF2 variants were independent factors associated with increased LBP level.

CONCLUSIONS

Endotoxemia is positively associated with NASH and significant fibrosis. The association between TM6SF2 and endotoxemia warrants further investigations. The findings may shed light on the pathogenesis of NASH and inform a novel treatment target.

The Roles of the Gut Microbiota and Toll-like Receptors in Obesity and Nonalcoholic Fatty Liver Disease

Obesity is characterized by low-grade chronic inflammation and is closely associated with the cardiovascular diseases, diabetes, and nonalcoholic fatty liver disease. Emerging data demonstrate that the gut microbiota contributes to the development of obesity by regulating the innate immune system, including the Toll-like receptors (TLRs): an altered gut microbiota composition and elevated TLR ligands are observed in obese mice and humans. The changes in the gut microbiota include an increased abundance of Firmicutes phylum and a decreased abundance of Bacteroidetes phylum. The population of beneficial bacteria that function as probiotics is decreased whereas harmful bacteria that can produce lipopolysaccharide, a TLR4 ligand, are increased in the obese state. In addition, the gut permeability is increased in obesity, which allows the delivery of larger amounts of bacterial components to the liver through the portal vein. Immune cells recognize these bacterial components through TLRs and produce diverse cytokines that kill invading pathogens. However, the sustained activation of TLR signaling induces host damage due to chronic exposure to harmful cytokines, which are produced from TLR expressing cells, including monocytes/macrophages. In the obese state, the expression of TLR is increased in several organs, including the adipose tissue and the liver. At the cell level, negative regulators of TLR signaling are suppressed, leading to activation of TLR signaling. These alterations promote inflammation in many organs. Thus, the gut microbiota and TLR signaling are therapeutic targets in patients with obesity and its related diseases.

Oxidative Stress as a Critical Factor in Nonalcoholic Fatty Liver Disease Pathogenesis

SIGNIFICANCE

Nonalcoholic fatty liver disease (NAFLD), characterized by liver triacylglycerol build-up, has been growing in the global world in concert with the raised prevalence of cardiometabolic disorders, including obesity, diabetes, and hyperlipemia. Redox imbalance has been suggested to be highly relevant to NAFLD pathogenesis. Recent Advances: As a major health problem, NAFLD progresses to the more severe nonalcoholic steatohepatitis (NASH) condition and predisposes susceptible individuals to liver and cardiovascular disease. Although NAFLD represents the predominant cause of chronic liver disorders, the mechanisms of its development and progression remain incompletely understood, even if various scientific groups ascribed them to the occurrence of insulin resistance, dyslipidemia, inflammation, and apoptosis. Nevertheless, oxidative stress (OxS) more and more appears as the most important pathological event during NAFLD development and the hallmark between simple steatosis and NASH manifestation.

CRITICAL ISSUES

The purpose of this article is to summarize recent developments in the understanding of NAFLD, essentially focusing on OxS as a major pathogenetic mechanism. Various attempts to translate reactive oxygen species (ROS) scavenging by antioxidants into experimental and clinical studies have yielded mostly encouraging results.

FUTURE DIRECTIONS

Although augmented concentrations of ROS and faulty antioxidant defense have been associated to NAFLD and related complications, mechanisms of action and proofs of principle should be highlighted to support the causative role of OxS and to translate its concept into the clinic. Antioxid. Redox Signal. 26, 519-541.

Synbiotic supplementation in lean patients with non-alcoholic fatty liver disease: a pilot, randomised, double-blind, placebo-controlled, clinical trial

Although non-alcoholic fatty liver disease (NAFLD) is the leading aetiology of liver disorders in the world, there is no proven treatment for NAFLD patients with normal or low BMI. The aim of this study was to evaluate the efficacy of synbiotics supplementation in NAFLD patients with normal or low BMI. In this randomised, double-blind, placebo-controlled, clinical trial, fifty patients with NAFLD were assigned to take either a synbiotic supplement or a placebo capsule for 28 weeks. Both groups were advised to follow a healthy lifestyle. At the end of the study, hepatic steatosis and fibrosis reduced in both groups; however, the mean reduction was significantly greater in the synbiotic group rather than in the placebo group (P<0·001). Furthermore, serum levels of fasting blood sugar, TAG and most of the inflammatory mediators reduced in the synbiotic group significantly compared with the placebo group (P<0·05). Our results provide evidence that synbiotic supplementation improves the main features of NAFLD in patients with normal and low BMI, at least partially through reduction in inflammatory indices. Further studies are needed to address the exact mechanism of action of these effects.

Beneficial effects of probiotic cholesterol-lowering strain of Enterococcus faecium WEFA23 from infants on diet-induced metabolic syndrome in rats

The aim of this study was to select probiotic Enterococcus strains that have the potential to improve metabolic syndrome (MS). Ten Enterococcus strains isolated from healthy infants were evaluated for their probiotic properties in vitro, and Enterococcus faecium WEFA23 was selected due to its cholesterol removal ability (1.89 ± 0.07 mg/10¹⁰ cfu), highest glycodeoxycholic acid-hydrolase activity (1.86 ± 0.01 U/mg), and strong adhesion capacity to Caco-2 cells (17.90 ± 0.19%). The safety of E. faecium WEFA23 was verified by acute oral administration in mice, and it was found to have no adverse effects on general health status, bacterial translocation, and gut mucosal histology. Moreover, the beneficial effects of E. faecium WEFA23 on high-fat diet-induced MS in rats were investigated, and we found WEFA23 significantly decreased body weight, serum lipid levels (total cholesterol, triacylglycerols, and low-density lipoprotein cholesterol), blood glucose level, and insulin resistance in rats fed with a high-fat diet. This indicated that administration of E. faecium WEFA23 improved almost all key markers of MS, including obesity, hyperlipidemia, hyperglycemia, and insulin resistance. Our results supported E. faecium WEFA23 as a candidate for cholesterol-lowering dairy products and improvement of MS. Our research provided novel insights on Enterococcus as a strategy to combat MS.

Precision medicine in alcoholic and nonalcoholic fatty liver disease via modulating the gut microbiota

Alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) represent a major health burden in industrialized countries. Although alcohol abuse and nutrition play a central role in disease pathogenesis, preclinical models support a contribution of the gut microbiota to ALD and NAFLD. This review describes changes in the intestinal microbiota compositions related to ALD and NAFLD. Findings from in vitro, animal, and human studies are used to explain how intestinal pathology contributes to disease progression. This review summarizes the effects of untargeted microbiome modifications using antibiotics and probiotics on liver disease in animals and humans. While both affect humoral inflammation, regression of advanced liver disease or mortality has not been demonstrated. This review further describes products secreted by Lactobacillus- and microbiota-derived metabolites, such as fatty acids and antioxidants, that could be used for precision medicine in the treatment of liver disease. A better understanding of host-microbial interactions is allowing discovery of novel therapeutic targets in the gut microbiota, enabling new treatment options that restore the intestinal ecosystem precisely and influence liver disease. The modulation options of the gut microbiota and precision medicine employing the gut microbiota presented in this review have excellent prospects to improve treatment of liver disease.

Probiotics and Liver Disease: Where Are We Now and Where Are We Going?

Probiotics are live, nonpathogenic bacteria capable of colonizing the colonic mucosa. The most common probiotics include strains of Lactobacillus or Bifidobacteria, which are part of the normal gastrointestinal microbiota. Initial studies of selected probiotic species have suggested potential efficacy in several gastrointestinal diseases including inflammatory bowel diseases (particularly pouchitis), antibiotic-related diarrhea, Clostridium difficile toxin-induced colitis, infectious diarrhea, irritable bowel syndrome, and allergy. The so-called "gut-liver axis" involves complex interaction between the liver parenchyma and gut microbiota. There is growing evidence to suggest that alteration in gut microbial components may affect the liver and can be a precipitating cofactor in development and modulating of chronic liver damage through ethanol, production of ammonia and endotoxin. This may allow for a better understanding of its role in the pathogenesis of verities of liver diseases and help to identify a microbial target for prevention and treatment of such diseases. This paper discusses the growing evidence that highlights the relationship between gut microbiota and development, prevention and treatment of numbers of liver diseases.

Interventions for preventing gestational diabetes mellitus: an overview of Cochrane Reviews

This is the protocol for a review and there is no abstract. The objectives are as follows:

To summarise the evidence from Cochrane systematic Reviews regarding the effects of interventions for preventing gestational diabetes mellitus.