Gut microbiota interactions with anti-diabetic medications and pathogenesis of type 2 diabetes mellitus

Metabolic syndrome’s new therapy: Supplement the gut microbiome

This letter to the editor discusses the publication on gut microbiome supplementation as therapy for metabolic syndrome. Gut microbiome dysbiosis disrupts intestinal bacterial homeostasis and is related to chronic inflammation, insulin resistance, cardiovascular diseases, type 2 diabetes mellitus, and obesity. Previous research has found that increasing the abundance of beneficial microbiota in the gut modulates metabolic syndrome by reducing chronic inflammation and insulin resistance. Prebiotics, probiotics, synbiotics, and postbiotics are often used as supplements to increase the number of beneficial microbes and thus the production of short-chain fatty acids, which have positive effects on the gut microbiome and metabolic syndrome. In this review article, the author summarizes the available supplements to increase the abundance of beneficial gut microbiota and reduce the abundance of harmful microbiota in patients with metabolic disorders. Our group is also researching the role of the gut microbiota in chronic liver disease. This article will be of great help to our research. At the end of the letter, the mechanism of the gut microbiota in chronic liver disease is discussed.

Gut microbiome supplementation as therapy for metabolic syndrome

The gut microbiome is defined as an ecological community of commensal symbiotic and pathogenic microorganisms that exist in our body. Gut microbiome dysbiosis is a condition of dysregulated and disrupted intestinal bacterial homeostasis, and recent evidence has shown that dysbiosis is related to chronic inflammation, insulin resistance, cardiovascular diseases (CVD), type 2 diabetes mellitus (T2DM), and obesity. It is well known that obesity, T2DM and CVD are caused or worsened by multiple factors like genetic predisposition, environmental factors, unhealthy high calorie diets, and sedentary lifestyle. However, recent evidence from human and mouse models suggest that the gut microbiome is also an active player in the modulation of metabolic syndrome, a set of risk factors including obesity, hyperglycemia, and dyslipidemia that increase the risk for CVD, T2DM, and other diseases. Current research aims to identify treatments to increase the number of beneficial microbiota in the gut microbiome in order to modulate metabolic syndrome by reducing chronic inflammation and insulin resistance. There is increasing interest in supplements, classified as prebiotics, probiotics, synbiotics, or postbiotics, and their effect on the gut microbiome and metabolic syndrome. In this review article, we have summarized current research on these supplements that are available to improve the abundance of beneficial gut microbiota and to reduce the harmful ones in patients with metabolic syndrome.

Gut-Derived Metabolite, Trimethylamine-N-oxide (TMAO) in Cardio-Metabolic Diseases: Detection, Mechanism, and Potential Therapeutics

Trimethylamine N-oxide (TMAO) is a biologically active gut microbiome-derived dietary metabolite. Recent studies have shown that high circulating plasma TMAO levels are closely associated with diseases such as atherosclerosis and hypertension, and metabolic disorders such as diabetes and hyperlipidemia, contributing to endothelial dysfunction. There is a growing interest to understand the mechanisms underlying TMAO-induced endothelial dysfunction in cardio-metabolic diseases. Endothelial dysfunction mediated by TMAO is mainly driven by inflammation and oxidative stress, which includes: (1) activation of foam cells; (2) upregulation of cytokines and adhesion molecules; (3) increased production of reactive oxygen species (ROS); (4) platelet hyperreactivity; and (5) reduced vascular tone. In this review, we summarize the potential roles of TMAO in inducing endothelial dysfunction and the mechanisms leading to the pathogenesis and progression of associated disease conditions. We also discuss the potential therapeutic strategies for the treatment of TMAO-induced endothelial dysfunction in cardio-metabolic diseases.

Baihu renshen decoction ameliorates type 2 diabetes mellitus in rats through affecting gut microbiota enhancing gut permeability and inhibiting TLR4/NF-κB-mediated inflammatory response

Baihu Rensheng decoction (BHRS) can effectively improve insulin resistance (IR) and decrease blood glucose in diabetic patients. However, its specific mechanism of action remains unclear. In this study, a type 2 diabetes mellitus (T2DM) rat model was established using a high-fat diet combined with streptozotocin (STZ) injection and treated with BHRS. Firstly, the therapeutic and anti-inflammatory effects of BHRS on T2DM were evaluated. Secondly, the effects of BHRS on gut permeability were evaluated and western blot was used to detect the changes of TLR4/NF-κB pathway-related protein expressions in liver. Finally, 16S rRNA sequencing was used to detect alteration of gut microbiota diversity and abundance in rats after BHRS treatment. Our results showed that BHRS could alleviate the hyperglycemia, hyperlipidemia, IR, and pathological changes of liver, pancreas, and kidney in T2DM rats. BHRS could also decrease the levels of pro-inflammatory cytokines and inhibit the oxidative stress. Immunohistochemistry showed BHRS could increase the expression tight junction-related proteins (ZO-1 and occludin) in colon. Besides, the level of LPS in serum was decreased after BHRS treatment. Western blot results showed that the protein expression of TLR4, MyD88 and the phosphorylation IκB, and NF-κBp65 were lowered after BHRS treatment. 16S rRNA sequencing showed that BHRS treatment altered the diversity of gut microbiotra and decreases the Firmicutes/Bacteroidetes (F to B) ratio at the phylum level. At the genus level, BHRS could increase the relative abundances of Lactobacillus, Blautia, and Anaerostipes and decrease the relative abundances of Allobaculum, Candidatus Saccharimonas, and Ruminococcus. In conclusion, our study revealed the various ameliorative effects of BHRS on T2DM, including improving the liver and kidney functions and alleviating the hyperglycemia, hyperlipidemia, pathological changes, oxidative stress and inflammatory response. The mechanisms of BHRS on T2DM are likely linked to the repair of gut barrier and the inhibition of TLR4/NF-κB-mediated inflammatory response and the improvement in the dysbiosis of gut microbiota.