scholarly journals The role of the gut microbiome and exercise in non-alcoholic fatty liver disease

2020 ◽  
Vol 13 ◽  
pp. 175628482094174
Author(s):  
Veera Houttu ◽  
Ulrika Boulund ◽  
Aldo Grefhorst ◽  
Maarten R. Soeters ◽  
Sara-Joan Pinto-Sietsma ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Liver Disease ◽  
Fatty Liver ◽  
Gut Microbiome ◽  
Fatty Liver Disease ◽  
Inflammatory Responses ◽  
Alcoholic Fatty Liver ◽  
Alcoholic Fatty Liver Disease

In recent years, the human gut microbiome has been found to influence a multitude of non-communicable diseases such as cardiovascular disease and metabolic syndrome, with its components type 2 diabetes mellitus and obesity. It is recognized to be mainly influenced by environmental factors, such as lifestyle, but also genetics may play a role. The interaction of gut microbiota and obesity has been widely studied, but in regard to non-alcoholic fatty liver disease (NAFLD) as a manifestation of obesity and insulin resistance, the causal role of the gut microbiome has not been fully established. The mechanisms by which the gut microbiome influences lipid accumulation, inflammatory responses, and occurrence of fibrosis in the liver are a topic of active research. In addition, the influence of exercise on gut microbiome composition is also being investigated. In clinical trials, exercise reduced hepatic steatosis independently of weight reduction. Other studies indicate that exercise may modulate the gut microbiome. This puts forward the question whether exercise could mediate its beneficial effects on NAFLD via changes in gut microbiome. Yet, the specific mechanisms underlying this potential connection are largely unknown. Thus, associative evidence from clinical trials, as well as mechanistic studies in vivo are called for to elucidate the relationship between exercise and the gut microbiome in NAFLD. Here, we review the current literature on exercise and the gut microbiome in NAFLD.

scholarly journals The role of the gut microbiome and diet in the pathogenesis of non-alcoholic fatty liver disease

2021 ◽  
Vol 27 (1) ◽  
pp. 22-43
Author(s):  
Erica Jennison ◽  
Christopher D. Byrne
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
Gut Microbiome ◽  
Fatty Liver Disease ◽  
Dietary Factors ◽  
Current Evidence ◽  
Alcoholic Fatty Liver ◽  
Close Relationship ◽  
Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease, with a prevalence that is increasing in parallel with the global rise in obesity and type 2 diabetes mellitus. The pathogenesis of NAFLD is complex and multifactorial, involving environmental, genetic and metabolic factors. The role of the diet and the gut microbiome is gaining interest as a significant factor in NAFLD pathogenesis. Dietary factors induce alterations in the composition of the gut microbiome (dysbiosis), commonly reflected by a reduction of the beneficial species and an increase in pathogenic microbiota. Due to the close relationship between the gut and liver, altering the gut microbiome can affect liver functions; promoting hepatic steatosis and inflammation. This review summarises the current evidence supporting an association between NAFLD and the gut microbiome and dietary factors. The review also explores potential underlying mechanisms underpinning these associations and whether manipulation of the gut microbiome is a potential therapeutic strategy to prevent or treat NAFLD.

scholarly journals Understanding the Role of the Gut Microbiome and Microbial Metabolites in Non-Alcoholic Fatty Liver Disease: Current Evidence and Perspectives

Biomolecules ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 56
Author(s):  
Natalia Vallianou ◽  
Gerasimos Socrates Christodoulatos ◽  
Irene Karampela ◽  
Dimitrios Tsilingiris ◽  
Faidon Magkos ◽  
...  
Keyword(s):  
Liver Disease ◽  
Gut Microbiota ◽  
Fatty Liver ◽  
Gut Microbiome ◽  
Fatty Liver Disease ◽  
Microbial Metabolites ◽  
Alcoholic Fatty Liver ◽  
Gut Dysbiosis ◽  
Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. NAFLD begins as a relatively benign hepatic steatosis which can evolve to non-alcoholic steatohepatitis (NASH); the risk of cirrhosis and hepatocellular carcinoma (HCC) increases when fibrosis is present. NAFLD represents a complex process implicating numerous factors—genetic, metabolic, and dietary—intertwined in a multi-hit etiopathogenetic model. Recent data have highlighted the role of gut dysbiosis, which may render the bowel more permeable, leading to increased free fatty acid absorption, bacterial migration, and a parallel release of toxic bacterial products, lipopolysaccharide (LPS), and proinflammatory cytokines that initiate and sustain inflammation. Although gut dysbiosis is present in each disease stage, there is currently no single microbial signature to distinguish or predict which patients will evolve from NAFLD to NASH and HCC. Using 16S rRNA sequencing, the majority of patients with NAFLD/NASH exhibit increased numbers of Bacteroidetes and differences in the presence of Firmicutes, resulting in a decreased F/B ratio in most studies. They also present an increased proportion of species belonging to Clostridium, Anaerobacter, Streptococcus, Escherichia, and Lactobacillus, whereas Oscillibacter, Flavonifaractor, Odoribacter, and Alistipes spp. are less prominent. In comparison to healthy controls, patients with NASH show a higher abundance of Proteobacteria, Enterobacteriaceae, and Escherichia spp., while Faecalibacterium prausnitzii and Akkermansia muciniphila are diminished. Children with NAFLD/NASH have a decreased proportion of Oscillospira spp. accompanied by an elevated proportion of Dorea, Blautia, Prevotella copri, and Ruminococcus spp. Gut microbiota composition may vary between population groups and different stages of NAFLD, making any conclusive or causative claims about gut microbiota profiles in NAFLD patients challenging. Moreover, various metabolites may be involved in the pathogenesis of NAFLD, such as short-chain fatty acids, lipopolysaccharide, bile acids, choline and trimethylamine-N-oxide, and ammonia. In this review, we summarize the role of the gut microbiome and metabolites in NAFLD pathogenesis, and we discuss potential preventive and therapeutic interventions related to the gut microbiome, such as the administration of probiotics, prebiotics, synbiotics, antibiotics, and bacteriophages, as well as the contribution of bariatric surgery and fecal microbiota transplantation in the therapeutic armamentarium against NAFLD. Larger and longer-term prospective studies, including well-defined cohorts as well as a multi-omics approach, are required to better identify the associations between the gut microbiome, microbial metabolites, and NAFLD occurrence and progression.

scholarly journals The Role of the Transsulfuration Pathway in Non-Alcoholic Fatty Liver Disease

2021 ◽  
Vol 10 (5) ◽  
pp. 1081
Author(s):  
Mikkel Parsberg Werge ◽  
Adrian McCann ◽  
Elisabeth Douglas Galsgaard ◽  
Dorte Holst ◽  
Anne Bugge ◽  
...  
Keyword(s):  
Liver Disease ◽  
Animal Models ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
Alcoholic Fatty Liver ◽  
Precise Control ◽  
Transsulfuration Pathway ◽  
Global Population ◽  
Alcoholic Fatty Liver Disease

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing and approximately 25% of the global population may have NAFLD. NAFLD is associated with obesity and metabolic syndrome, but its pathophysiology is complex and only partly understood. The transsulfuration pathway (TSP) is a metabolic pathway regulating homocysteine and cysteine metabolism and is vital in controlling sulfur balance in the organism. Precise control of this pathway is critical for maintenance of optimal cellular function. The TSP is closely linked to other pathways such as the folate and methionine cycles, hydrogen sulfide (H2S) and glutathione (GSH) production. Impaired activity of the TSP will cause an increase in homocysteine and a decrease in cysteine levels. Homocysteine will also be increased due to impairment of the folate and methionine cycles. The key enzymes of the TSP, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE), are highly expressed in the liver and deficient CBS and CSE expression causes hepatic steatosis, inflammation, and fibrosis in animal models. A causative link between the TSP and NAFLD has not been established. However, dysfunctions in the TSP and related pathways, in terms of enzyme expression and the plasma levels of the metabolites (e.g., homocysteine, cystathionine, and cysteine), have been reported in NAFLD and liver cirrhosis in both animal models and humans. Further investigation of the TSP in relation to NAFLD may reveal mechanisms involved in the development and progression of NAFLD.

scholarly journals The Role of Oxidative Stress in NAFLD–NASH–HCC Transition—Focus on NADPH Oxidases

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 687
Author(s):  
Daniela Gabbia ◽  
Luana Cannella ◽  
Sara De De Martin
Keyword(s):  
Oxidative Stress ◽  
Liver Disease ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
Current Knowledge ◽  
Mechanisms Of Action ◽  
Nadph Oxidases ◽  
Alcoholic Fatty Liver ◽  
Alcoholic Fatty Liver Disease

A peculiar role for oxidative stress in non-alcoholic fatty liver disease (NAFLD) and its transition to the inflammatory complication non-alcoholic steatohepatitis (NASH), as well as in its threatening evolution to hepatocellular carcinoma (HCC), is supported by numerous experimental and clinical studies. NADPH oxidases (NOXs) are enzymes producing reactive oxygen species (ROS), whose abundance in liver cells is closely related to inflammation and immune responses. Here, we reviewed recent findings regarding this topic, focusing on the role of NOXs in the different stages of fatty liver disease and describing the current knowledge about their mechanisms of action. We conclude that, although there is a consensus that NOX-produced ROS are toxic in non-neoplastic conditions due to their role in the inflammatory vicious cycle sustaining the transition of NAFLD to NASH, their effect is controversial in the neoplastic transition towards HCC. In this regard, there are indications of a differential effect of NOX isoforms, since NOX1 and NOX2 play a detrimental role, whereas increased NOX4 expression appears to be correlated with better HCC prognosis in some studies. Further studies are needed to fully unravel the mechanisms of action of NOXs and their relationships with the signaling pathways modulating steatosis and liver cancer development.

scholarly journals Role of illness perception and self-efficacy in lifestyle modification among non-alcoholic fatty liver disease patients

2017 ◽  
Vol 23 (10) ◽  
pp. 1881 ◽  
Author(s):  
Shira Zelber-Sagi ◽  
Shiran Bord ◽  
Gali Dror-Lavi ◽  
Matthew Lee Smith ◽  
Samuel D Towne Jr ◽  
...  
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
Self Efficacy ◽  
Fatty Liver Disease ◽  
Lifestyle Modification ◽  
Illness Perception ◽  
Alcoholic Fatty Liver ◽  
Alcoholic Fatty Liver Disease

scholarly journals A Narrative Review on the Role of AMPK on De Novo Lipogenesis in Non-Alcoholic Fatty Liver Disease: Evidence from Human Studies

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1822
Author(s):  
Christian von Loeffelholz ◽  
Sina M. Coldewey ◽  
Andreas L. Birkenfeld
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
Mammalian Cells ◽  
De Novo ◽  
Adenosine Monophosphate ◽  
De Novo Lipogenesis ◽  
Alcoholic Fatty Liver ◽  
Alcoholic Fatty Liver Disease

5′AMP-activated protein kinase (AMPK) is known as metabolic sensor in mammalian cells that becomes activated by an increasing adenosine monophosphate (AMP)/adenosine triphosphate (ATP) ratio. The heterotrimeric AMPK protein comprises three subunits, each of which has multiple phosphorylation sites, playing an important role in the regulation of essential molecular pathways. By phosphorylation of downstream proteins and modulation of gene transcription AMPK functions as a master switch of energy homeostasis in tissues with high metabolic turnover, such as the liver, skeletal muscle, and adipose tissue. Regulation of AMPK under conditions of chronic caloric oversupply emerged as substantial research target to get deeper insight into the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Evidence supporting the role of AMPK in NAFLD is mainly derived from preclinical cell culture and animal studies. Dysbalanced de novo lipogenesis has been identified as one of the key processes in NAFLD pathogenesis. Thus, the scope of this review is to provide an integrative overview of evidence, in particular from clinical studies and human samples, on the role of AMPK in the regulation of primarily de novo lipogenesis in human NAFLD.

The role of Hepassocin in the development of non-alcoholic fatty liver disease

2013 ◽  
Vol 59 (5) ◽  
pp. 1065-1072 ◽  
Author(s):  
Hung-Tsung Wu ◽  
Feng-Hwa Lu ◽  
Horng-Yih Ou ◽  
Yu-Chu Su ◽  
Hao-Chang Hung ◽  
...  
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
Alcoholic Fatty Liver ◽  
Alcoholic Fatty Liver Disease
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