scholarly journals The role of the gut microbiome and its metabolites in metabolic diseases

2020 ◽  
Author(s):  
Jiayu Wu ◽  
Kai Wang ◽  
Xuemei Wang ◽  
Yanli Pang ◽  
Changtao Jiang

AbstractIt is well known that an unhealthy lifestyle is a major risk factor for metabolic diseases, while in recent years, accumulating evidence has demonstrated that the gut microbiome and its metabolites also play a crucial role in the onset and development of many metabolic diseases, including obesity, type 2 diabetes, nonalcoholic fatty liver disease, cardiovascular disease and so on. Numerous microorganisms dwell in the gastrointestinal tract, which is a key interface for energy acquisition and can metabolize dietary nutrients into many bioactive substances, thus acting as a link between the gut microbiome and its host. The gut microbiome is shaped by host genetics, immune responses and dietary factors. The metabolic and immune potential of the gut microbiome determines its significance in host health and diseases. Therefore, targeting the gut microbiome and relevant metabolic pathways would be effective therapeutic treatments for many metabolic diseases in the near future. This review will summarize information about the role of the gut microbiome in organism metabolism and the relationship between gut microbiome-derived metabolites and the pathogenesis of many metabolic diseases. Furthermore, recent advances in improving metabolic diseases by regulating the gut microbiome will be discussed.

2019 ◽  
Vol 20 (7) ◽  
pp. 750-758 ◽  
Author(s):  
Yi Wu ◽  
Hengxun He ◽  
Zhibin Cheng ◽  
Yueyu Bai ◽  
Xi Ma

Obesity is one of the main challenges of public health in the 21st century. Obesity can induce a series of chronic metabolic diseases, such as diabetes, dyslipidemia, hypertension and nonalcoholic fatty liver, which seriously affect human health. Gut-brain axis, the two-direction pathway formed between enteric nervous system and central nervous system, plays a vital role in the occurrence and development of obesity. Gastrointestinal signals are projected through the gut-brain axis to nervous system, and respond to various gastrointestinal stimulation. The central nervous system regulates visceral activity through the gut-brain axis. Brain-gut peptides have important regulatory roles in the gut-brain axis. The brain-gut peptides of the gastrointestinal system and the nervous system regulate the gastrointestinal movement, feeling, secretion, absorption and other complex functions through endocrine, neurosecretion and paracrine to secrete peptides. Both neuropeptide Y and peptide YY belong to the pancreatic polypeptide family and are important brain-gut peptides. Neuropeptide Y and peptide YY have functions that are closely related to appetite regulation and obesity formation. This review describes the role of the gutbrain axis in regulating appetite and maintaining energy balance, and the functions of brain-gut peptides neuropeptide Y and peptide YY in obesity. The relationship between NPY and PYY and the interaction between the NPY-PYY signaling with the gut microbiota are also described in this review.


2017 ◽  
Vol 89 (8) ◽  
pp. 120-128 ◽  
Author(s):  
K A Aitbaev ◽  
I T Murkamilov ◽  
V V Fomin

The paper gives an update on the role of the gut microbiome (GM) in the development of nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, alcoholic liver disease, liver cirrhosis (LC), and its complications, such as hepatic encephalopathy (HE) and hepatocellular carcinoma (HCC), and discusses the possibilities of its correction with prebiotics, probiotics, synbiotics, antibiotics, and fecal microbiota transplantation (FMT). The pathophysiology of the liver diseases in question demonstrates some common features that are characterized by pathogenic changes in the composition of the gastrointestinal tract microflora, by intestinal barrier impairments, by development of endotoxemia, by increased liver expression of proinflammatory factors, and by development of liver inflammation. In progressive liver disease, the above changes are more pronounced, which contributes to the development of LC, HE, and HCC. GM modulation using prebiotics, probiotics, synbiotics, antibiotics, and FMT diminishes dysbacteriosis, strengthens the intestinal mucosal barrier, reduces endotoxemia and liver damage, and positively affects the clinical manifestations of HE. Further investigations are needed, especially in humans, firstly, to assess a relationship of GM to the development of liver diseases in more detail and, secondly, to obtain evidence indicating the therapeutic efficacy of GM-modulating agents in large-scale, well-designed, randomized, controlled, multicenter studies.


2019 ◽  
Vol 244 (6) ◽  
pp. 408-418 ◽  
Author(s):  
Tien S Dong ◽  
Jonathan P Jacobs

Over the last several years, a growing body of literature has linked the gut microbiome to human health and diseases such as obesity, metabolic syndrome, and nonalcoholic fatty liver disease (NAFLD). This paper will review the current literature investigating the influence of diets associated with metabolic disorders on the microbiome and how those changes promote susceptibility to metabolic disorders. It will then focus in-depth on the role of the gut microbiome in NAFLD. The review will highlight associations of microbial composition and function with progression of NAFLD in patients and discuss potential mechanisms that link the gut microbiome to NAFLD. Finally, it will address limitations of existing studies along with future directions for microbiome research in NAFLD, including potential microbe-related treatments. Impact statement This invited minireview for the upcoming thematic issue on the microbiome addresses the role of the microbiome in nonalcoholic fatty liver disease (NAFLD). The incidence of NAFLD has increased greatly in recent years in parallel with the rise in obesity and is now believed to have a population prevalence of 20–40%. It is anticipated to soon become the primary cause of liver-related morbidity and mortality, and unfortunately, there are few treatment options. Therefore, there is a critical need for improved understanding of NAFLD pathophysiology to provide new avenues for therapeutic intervention. In this paper, we have reviewed evidence from human and animal model studies that have associated microbiome composition and microbial metabolites with development and progression of NAFLD. We have also discussed proposed mechanisms by which the microbiome could contribute to NAFLD pathogenesis and addressed future directions for this field.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Giljae Lee ◽  
Hyun Ju You ◽  
Jasmohan S. Bajaj ◽  
Sae Kyung Joo ◽  
Junsun Yu ◽  
...  

Abstract Nonalcoholic fatty liver disease (NAFLD) is associated with obesity but also found in non-obese individuals. Gut microbiome profiles of 171 Asians with biopsy-proven NAFLD and 31 non-NAFLD controls are analyzed using 16S rRNA sequencing; an independent Western cohort is used for external validation. Subjects are classified into three subgroups according to histological spectra of NAFLD or fibrosis severity. Significant alterations in microbiome diversity are observed according to fibrosis severity in non-obese, but not obese, subjects. Ruminococcaceae and Veillonellaceae are the main microbiota associated with fibrosis severity in non-obese subjects. Furthermore, stool bile acids and propionate are elevated, especially in non-obese subjects with significant fibrosis. Fibrosis-related Ruminococcaceae and Veillonellaceae species undergo metagenome sequencing, and four representative species are administered in three mouse NAFLD models to evaluate their effects on liver damage. This study provides the evidence for the role of the microbiome in the liver fibrosis pathogenesis, especially in non-obese subjects.


2021 ◽  
Vol 27 (1) ◽  
pp. 22-43
Author(s):  
Erica Jennison ◽  
Christopher D. Byrne

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.


2015 ◽  
Vol 4 (4) ◽  
pp. 123-29
Author(s):  
Banafshe Hosseini ◽  
Kurosh Djafarian

Lifestyle factors and nutritional status are regarded as critical determinants of normal reproductive function. Hence, the role of dietary nutrients has attracted the attention of researchers to the extent that some studies have addressed the effects of diet on the risk of male infertility. This study aimed to summarize the literature regarding the association between various dietary factors and male infertility. Literature searching for studies on male infertility and nutrition, published between January 1982 and May 2015, was performed using PubMed and Scopus databases. The bibliographies of included studies were also searched for additional references. About 65 articles were identified and after the elimination of irrelevant studies, 35 related studies available for review were examined. Studies have indicated that in men with idiopathic infertility, omega-3 intervention resulted in significant improvement in total sperm count as well as sperm cell density. Moreover, several studies have shown that higher intake of poultry, cereals, fruit and vegetables may play a beneficial role in male infertility; although, some studies have not attained such results. Taken as a whole, studies demonstrated that food consumption may play a major role in preventing or facilitating male infertility. Further studies are needed to clarify this association. [GMJ.2015;4(4):123-29]


Gut ◽  
2020 ◽  
Vol 69 (3) ◽  
pp. 513-522 ◽  
Author(s):  
Xia Chen ◽  
Pan Li ◽  
Mian Liu ◽  
Huimin Zheng ◽  
Yan He ◽  
...  

ObjectivePre-eclampsia (PE) is one of the malignant metabolic diseases that complicate pregnancy. Gut dysbiosis has been identified for causing metabolic diseases, but the role of gut microbiome in the pathogenesis of PE remains unknown.DesignWe performed a case–control study to compare the faecal microbiome of PE and normotensive pregnant women by 16S ribosomal RNA (rRNA) sequencing. To address the causative relationship between gut dysbiosis and PE, we used faecal microbiota transplantation (FMT) in an antibiotic-treated mouse model. Finally, we determined the microbiome translocation and immune responses in human and mouse placental samples by 16S rRNA sequencing, quantitative PCR and in situ hybridisation.ResultsPatients with PE showed reduced bacterial diversity with obvious dysbiosis. Opportunistic pathogens, particularly Fusobacterium and Veillonella, were enriched, whereas beneficial bacteria, including Faecalibacterium and Akkermansia, were markedly depleted in the PE group. The abundances of these discriminative bacteria were correlated with blood pressure (BP), proteinuria, aminotransferase and creatinine levels. On successful colonisation, the gut microbiome from patients with PE triggered a dramatic, increased pregestational BP of recipient mice, which further increased after gestation. In addition, the PE-transplanted group showed increased proteinuria, embryonic resorption and lower fetal and placental weights. Their T regulatory/helper-17 balance in the small intestine and spleen was disturbed with more severe intestinal leakage. In the placenta of both patients with PE and PE-FMT mice, the total bacteria, Fusobacterium, and inflammatory cytokine levels were significantly increased.ConclusionsThis study suggests that the gut microbiome of patients with PE is dysbiotic and contributes to disease pathogenesis.


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