scholarly journals Influence of Gut Microbiota on Subclinical Inflammation and Insulin Resistance

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Bruno Melo Carvalho ◽  
Mario Jose Abdalla Saad

Obesity is the main condition that is correlated with the appearance of insulin resistance, which is the major link among its comorbidities, such as type 2 diabetes, nonalcoholic fatty liver disease, cardiovascular and neurodegenerative diseases, and several types of cancer. Obesity affects a large number of individuals worldwide; it degrades human health and quality of life. Here, we review the role of the gut microbiota in the pathophysiology of obesity and type 2 diabetes, which is promoted by a bacterial diversity shift mediated by overnutrition. Whole bacteria, their products, and metabolites undergo increased translocation through the gut epithelium to the circulation due to degraded tight junctions and the consequent increase in intestinal permeability that culminates in inflammation and insulin resistance. Several strategies focusing on modulation of the gut microbiota (antibiotics, probiotics, and prebiotics) are being experimentally employed in metabolic derangement in order to reduce intestinal permeability, increase the production of short chain fatty acids and anorectic gut hormones, and promote insulin sensitivity to counteract the inflammatory status and insulin resistance found in obese individuals.

Nutrients ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3719
Author(s):  
Daniela Maria Tanase ◽  
Evelina Maria Gosav ◽  
Ecaterina Neculae ◽  
Claudia Florida Costea ◽  
Manuela Ciocoiu ◽  
...  

Type 2 diabetes mellitus (T2DM) remains one of the most problematic and economic consumer disorders worldwide, with growing prevalence and incidence. Over the last years, substantial research has highlighted the intricate relationship among gut microbiota, dysbiosis and metabolic syndromes development. Changes in the gut microbiome composition lead to an imbalanced gastrointestinal habitat which promotes abnormal production of metabolites, inflammatory status, glucose metabolism alteration and even insulin resistance (IR). Short-chain fatty acids (SCFAs), trimethylamine N-oxide (TMAO), lipopolysaccharide, aromatic amino acids and their affiliated metabolites, contribute to T2DM via different metabolic and immunologic pathways. In this narrative review, we discuss the immunopathogenic mechanism behind gut dysbiosis, T2DM development and the major known diabetic microvascular complications (retinopathy, neuropathy and nephropathy), the beneficial use of pre- and pro-biotics and fecal microbiota transplantation in T2DM management and new findings and future perspectives in this field.


2017 ◽  
Vol 71 (Suppl. 1) ◽  
pp. 17-22 ◽  
Author(s):  
Junko Sato ◽  
Akio Kanazawa ◽  
Hirotaka Watada

Background: A high proportion of type 2 diabetes cases are associated with host genetic and environmental factors. During the past decade, microorganisms that inhabit the gut have emerged as contributors to the pathogenesis of obesity and type 2 diabetes. Therefore, manipulation of the human gut microbiota will provide essential clues regarding new therapeutic targets for diabetes. Summary: Several studies have established the presence of gut dysbiosis in patients with type 2 diabetes mellitus, even though there are some differences among the studies that could be explained by differences in ethnicity, diet, and methodology. Gut dysbiosis affects the quality and quantity of short-chain fatty acids and secondary bile acids that act as signaling molecules in energy, glucose, and lipid metabolism. In addition, gut dysbiosis affect intestinal permeability. In particular, a high-fat diet can lead to changes in the gut microbiota that strongly reduce intestinal permeability due to the malfunction of tight junction proteins, such as occludin and ZO-1 [<citeref rid="ref1">1</citeref>]. The formation of leaky gut results in increased plasma levels of lipopolysaccharide, which activate Toll-like receptor 4 and result in innate and adaptive immune responses [<citeref rid="ref2">2</citeref>]. Key messages: Gut dysbiosis play an important role in the pathogenesis of obesity and diabetes, for example, via chronic low-grade inflammation. Normalizing gut dysbiosis could be a new approach to overcome diseases of insulin resistance, such as diabetes mellitus.


Author(s):  
Dominic Salamone ◽  
Angela Albarosa Rivellese ◽  
Claudia Vetrani

AbstractGut microbiota and its metabolites have been shown to influence multiple physiological mechanisms related to human health. Among microbial metabolites, short-chain fatty acids (SCFA) are modulators of different metabolic pathways. On the other hand, several studies suggested that diet might influence gut microbiota composition and activity thus modulating the risk of metabolic disease, i.e. obesity, insulin resistance and type 2 diabetes. Among dietary component, dietary fibre may play a pivotal role by virtue of its prebiotic effect on fibre-fermenting bacteria, that may increase SCFA production. The aim of this review was to summarize and discuss current knowledge on the impact of dietary fibre as modulator of the relationship between glucose metabolism and microbiota composition in humans. More specifically, we analysed evidence from observational studies and randomized nutritional intervention investigating the relationship between gut microbiota, short-chain fatty acids and glucose metabolism. The possible mechanisms behind this association were also discussed.


Author(s):  
A. L. Cunningham ◽  
J. W. Stephens ◽  
D. A. Harris

AbstractObesity and type 2 diabetes mellitus (T2DM) are common, chronic metabolic disorders with associated significant long-term health problems at global epidemic levels. It is recognised that gut microbiota play a central role in maintaining host homeostasis and through technological advances in both animal and human models it is becoming clear that gut microbiota are heavily involved in key pathophysiological roles in the aetiology and progression of both conditions. This review will focus on current knowledge regarding microbiota interactions with short chain fatty acids, the host inflammatory response, signaling pathways, integrity of the intestinal barrier, the interaction of the gut-brain axis and the subsequent impact on the metabolic health of the host.


2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Hamed Ebrahimzadeh Leylabadlo ◽  
Hossein Samadi Kafil ◽  
Safar Farajnia ◽  
Dariush Shanehbandi ◽  
Seyed Yaghoub Moaddab ◽  
...  

2015 ◽  
Vol 172 (4) ◽  
pp. R167-R177 ◽  
Author(s):  
Kristine H Allin ◽  
Trine Nielsen ◽  
Oluf Pedersen

Perturbations of the composition and function of the gut microbiota have been associated with metabolic disorders including obesity, insulin resistance and type 2 diabetes. Studies on mice have demonstrated several underlying mechanisms including host signalling through bacterial lipopolysaccharides derived from the outer membranes of Gram-negative bacteria, bacterial fermentation of dietary fibres to short-chain fatty acids and bacterial modulation of bile acids. On top of this, an increased permeability of the intestinal epithelium may lead to increased absorption of macromolecules from the intestinal content resulting in systemic immune responses, low-grade inflammation and altered signalling pathways influencing lipid and glucose metabolism. While mechanistic studies on mice collectively support a causal role of the gut microbiota in metabolic diseases, the majority of studies in humans are correlative of nature and thus hinder causal inferences. Importantly, several factors known to influence the risk of type 2 diabetes, e.g. diet and age, have also been linked to alterations in the gut microbiota complicating the interpretation of correlative studies. However, based upon the available evidence, it is hypothesised that the gut microbiota may mediate or modulate the influence of lifestyle factors triggering development of type 2 diabetes. Thus, the aim of this review is to critically discuss the potential role of the gut microbiota in the pathophysiology and pathogenesis of type 2 diabetes.


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