scholarly journals Metformin Strongly Affects Gut Microbiome Composition in High-Fat Diet-Induced Type 2 Diabetes Mouse Model of Both Sexes

2021 ◽  
Vol 12 ◽  
Author(s):  
Laila Silamiķele ◽  
Ivars Silamiķelis ◽  
Monta Ustinova ◽  
Zane Kalniņa ◽  
Ilze Elbere ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Gut Microbiome ◽  
High Fat Diet ◽  
Abundant Species ◽  
Metformin Treatment ◽  
High Fat ◽  
Microbiome Composition ◽  
Before And After ◽  
Diabetes Mouse

Effects of metformin, the first-line drug for type 2 diabetes therapy, on gut microbiome composition in type 2 diabetes have been described in various studies both in human subjects and animals. However, the details of the molecular mechanisms of metformin action have not been fully understood. Moreover, there is a significant lack of information on how metformin affects gut microbiome composition in female mouse models, depending on sex and metabolic status in well controlled experimental setting. Our study aimed to examine metformin-induced alterations in gut microbiome diversity, composition, and functional implications of high-fat diet-induced type 2 diabetes mouse model, using, for the first time in mice study, the shotgun metagenomic sequencing that allows estimation of microorganisms at species level. We also employed a randomized block, factorial study design, and including 24 experimental units allocated to 8 treatment groups to systematically evaluate the effect of sex and metabolic status on metformin interaction with microbiome. We used DNA obtained from fecal samples representing gut microbiome before and after ten weeks-long metformin treatment. We identified 100 metformin-related differentially abundant species in high-fat diet-fed mice before and after the treatment, with most of the species relative abundances increased. In contrast, no significant changes were observed in control diet-fed mice. Functional analysis targeted to carbohydrate, lipid, and amino acid metabolism pathways revealed 14 significantly altered hierarchies. We also observed sex-specific differences in response to metformin treatment. Males experienced more pronounced changes in metabolic markers, while in females the extent of changes in gut microbiome representatives was more marked, indicated by 53 differentially abundant species with more remarkable Log fold changes compared to the combined-sex analysis. The same pattern manifested regarding the functional analysis, where we discovered 5 significantly affected hierarchies in female groups but not in males. Our results suggest that both sexes of animals should be included in future studies focusing on metformin effects on the gut microbiome.

scholarly journals Metformin strongly affects gut microbiome composition in high-fat diet-induced type 2 diabetes mouse model of both sexes

2020 ◽  
Author(s):  
Laila Silamiķele ◽  
Ivars Silamiķelis ◽  
Monta Ustinova ◽  
Zane Kalniņa ◽  
Ilze Elbere ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Gut Microbiome ◽  
High Fat Diet ◽  
Abundant Species ◽  
Metformin Treatment ◽  
High Fat ◽  
Microbiome Composition ◽  
Before And After ◽  
Diabetes Mouse

AbstractEffects of metformin, the first-line drug for type 2 diabetes therapy, on gut microbiome composition in type 2 diabetes have been described in various studies both in human subjects and animals. However, the details of the molecular mechanisms of metformin action have not been fully understood. Moreover, there is a significant lack of information on how metformin affects gut microbiome composition in female mice models, as most of the existing studies have focused on males only.Our study aimed to examine metformin-induced alterations in gut microbiome diversity and composition of high-fat diet-induced type 2 diabetes mouse model, employing a randomized block, factorial study design, and including 24 experimental units allocated to 8 treatment groups. We performed shotgun metagenomic sequencing using DNA obtained from fecal samples representing gut microbiome before and after ten weeks-long metformin treatment.We identified 100 metformin-related differentially abundant species in high-fat diet-fed mice before and after the treatment, with most of the species abundances increased. In contrast, no significant changes were observed in control diet-fed mice.We also observed sex-specific differences in response to metformin treatment. Males experienced more pronounced changes in metabolic markers, while, in females, the extent of changes in gut microbiome representatives was more marked, indicated by 53 differentially abundant species with more remarkable Log fold changes compared to the combined-sex analysis. Our results suggest that both sexes of animals should be included in future studies focusing on metformin effects on the gut microbiome.

scholarly journals Supplementation of Geranylgeraniol and Tocotrienols to High-Fat Diet Shifts the Gut Microbiome Composition and Function in Type 2 Diabetic Mice

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 393-393
Author(s):  
Moamen Elmassry ◽  
Eunhee Chung ◽  
Abdul Hamood ◽  
Chwan-Li Shen
Keyword(s):  
Relative Abundance ◽  
Gut Microbiome ◽  
High Fat Diet ◽  
Alpha Diversity ◽  
Control Group ◽  
Rrna Gene ◽  
High Fat ◽  
Microbiome Composition ◽  
And Function

Abstract Objectives In recent years, characterization of gut microbiota composition and function were linked to the progression of type 2 diabetes mellitus. Recent evidence showed that Geranylgeraniol, an isoprenoid found in fruits, vegetables, and grains, improves glucose homeostasis. Similarly, Tocotrienols, a subfamily of vitamin E, also contains anti-diabetic properties. In this study, we examined the combined effect of geranylgeraniol and tocotrienols on the composition and function of gut microbiome in obese male mice. Methods Forty male C57BL/6J mice were assigned to 4 groups in a factorial design as follows: high-fat diet (HFD) (control group), HFD + geranylgeraniol [400 mg/kg diet] (GG group), HFD + tocotrienols [400 mg/kg diet] (TT group), and HFD + geranylgeraniol + tocotrienols (G + T group) for 14 weeks. 16S rRNA gene sequencing was done from cecal samples and microbiome and data analysis was performed with QIIME2 and PICRUSt2. Results Across all groups, the most abundant phyla were Verrucomicrobia, Firmicutes, Bacteroidetes, and Actinobacteria. There was no difference in alpha diversity among different groups. Different treatments influenced the relative abundance of certain bacteria. In the Bacteroidetes phylum, the relative abundance of family S24–7 increased in the TT group only. In the Firmicutes phylum, the relative abundance of family Lachnospiraceae was reduced upon the supplementation of geranylgeraniol or tocotrienols; individually or in combination. In Verrucomicrobia phylum, Akkermansia muciniphila relative abundance was reduced in the TT group but increased in the G + T group. The results of functional profiling of the gut microbiome revealed that geranylgeraniol supplementation caused an increase in the proportion of biosynthetic pathways related to purine, pyrimidine, and inosine-5’-phosphate and hexitol fermentation, and a decrease in the proportion of pathways involved in the biosynthesis of isoleucine, valine, histidine, arginine, and chorismate. The G + T group increased pathways related to thiamine diphosphate biosynthesis, and decreased others involved into sulfur oxidation and methylerythritol phosphate. Conclusions The influence of geranylgeraniol and tocotrienols supplementation on gut microbiome composition and function, suggests a prebiotic potential for the potential of geranylgeraniol and tocotrienols. Funding Sources American River Nutrition, LLC, Hadley, MA.

A Mechanistic Model of Gut–Brain Axis Perturbation and High-Fat Diet Pathways to Gut Microbiome Homeostatic Disruption, Systemic Inflammation, and Type 2 Diabetes

2019 ◽  
Vol 21 (4) ◽  
pp. 384-399 ◽  
Author(s):  
Kelley Newlin Lew ◽  
Angela Starkweather ◽  
Xiaomei Cong ◽  
Michelle Judge
Keyword(s):  
Risk Factors ◽  
Type 2 Diabetes ◽  
Systemic Inflammation ◽  
Gut Microbiome ◽  
High Fat Diet ◽  
Mechanistic Model ◽  
High Fat ◽  
Β Cell ◽  
Cell Decline

Type 2 diabetes (T2D) is a highly prevalent metabolic disease, affecting nearly 10% of the American population. Although the etiopathogenesis of T2D remains poorly understood, advances in DNA sequencing technologies have allowed for sophisticated interrogation of the human microbiome, providing insight into the role of the gut microbiome in the development and progression of T2D. An emerging body of research reveals that gut–brain axis (GBA) perturbations and a high-fat diet (HFD), along with other modifiable and nonmodifiable risk factors, contribute to gut microbiome homeostatic imbalance. Homeostatic imbalance or disruption increases gut wall permeability and facilitates translocation of endotoxins (lipopolysaccharides) into the circulation with resultant systemic inflammation. Chronic, low-grade systemic inflammation ensues with pro-inflammatory pathways activated, contributing to obesity, insulin resistance (IR), pancreatic β-cell decline, and, thereby, T2D. While GBA perturbations and HFD are implicated in provoking these conditions, prior mechanistic models have tended to examine HFD and GBA pathways exclusively without considering their shared pathways to T2D. Addressing this gap, this article proposes a mechanistic model informed by animal and human studies to advance scientific understanding of (1) modifiable and nonmodifiable risk factors for gut microbiome homeostatic disruption, (2) HFD and GBA pathways contributing to homeostatic disruption, and (3) shared GBA and HFD pro-inflammatory pathways to obesity, IR, β-cell decline, and T2D. The proposed mechanistic model, based on the extant literature, proposes a framework for studying the complex relationships of the gut microbiome to T2D to advance study in this promising area of research.

scholarly journals A Possible Mechanism of Metformin in Improving Insulin Resistance in Diabetic Rat Models

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Mengsiyu Li ◽  
Xiaowen Hu ◽  
Yeqiu Xu ◽  
Xiaolin Hu ◽  
Chunxue Zhang ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
High Fat Diet ◽  
Hepg2 Cells ◽  
Diabetic Rats ◽  
Enzyme Linked Immunosorbent Assay ◽  
Metformin Treatment ◽  
High Fat ◽  
Rat Models

Background. Type 2 diabetes has become one of the most common diseases worldwide, causing a serious social burden. As a first-line treatment for diabetes, metformin can effectively improve insulin resistance. It has been reported that 12α-hydroxylated BA (mainly CA) is associated with insulin resistance. The purpose of this study was to analyze the changes in CA and possible signaling mechanisms in diabetic rats after metformin intervention. Methods. HepG2 cells were cultured after adding different concentrations of metformin. The cell viability was measured using CCK8 kit, and the expression of FXR, MAFG, and CYP8B1 in cells was detected by WB. The rat models of type 2 diabetes were induced by low-dose streptozotocin by feeding a high-fat diet, and the control rats (CON) were fed on normal food; the diabetic rats (DM) were given a high-fat diet without supplementation with metformin, while the metformin-treated diabetic rats (DM + MET) were given a high-fat diet and supplemented with metformin. Biochemical parameters were detected at the end of the test. Expression levels of FXR, CYP8B1, and MAFG were assessed by WB. Serum CA were measured using an enzyme-linked immunosorbent assay (ELISA). Results. In HepG2 cells, metformin dose-dependently enhanced the transcriptional activity of FXR and MAFG and inhibited the expression of CYP8B1. Metformin-treated DM rats showed improved glucose and bile acid metabolism. In addition, significantly increased FXR and MAFG and decreased CYP8B1 were observed in DM + MET rats. At the same time, the CA content of metformin-treated rats was lower than that of diabetic rats. Conclusion. Changes in CA synthesis after metformin treatment may be associated with inhibition of CYP8B1. These results may play an important role in improving insulin sensitivity after metformin treatment.

scholarly journals Time-of-Day-Dependent Effects of Bromocriptine to Ameliorate Vascular Pathology and Metabolic Syndrome in SHR Rats Held on High Fat Diet

2021 ◽  
Vol 22 (11) ◽  
pp. 6142
Author(s):  
Michael Ezrokhi ◽  
Yahong Zhang ◽  
Shuqin Luo ◽  
Anthony H. Cincotta
Keyword(s):  
Type 2 Diabetes ◽  
Metabolic Syndrome ◽  
High Fat Diet ◽  
Nitrosative Stress ◽  
Time Of Day ◽  
Vascular Pathology ◽  
Mrna Levels ◽  
High Fat ◽  
Nadph Oxidase 4

The treatment of type 2 diabetes patients with bromocriptine-QR, a unique, quick release micronized formulation of bromocriptine, improves glycemic control and reduces adverse cardiovascular events. While the improvement of glycemic control is largely the result of improved postprandial hepatic glucose metabolism and insulin action, the mechanisms underlying the drug’s cardioprotective effects are less well defined. Bromocriptine is a sympatholytic dopamine agonist and reduces the elevated sympathetic tone, characteristic of metabolic syndrome and type 2 diabetes, which potentiates elevations of vascular oxidative/nitrosative stress, known to precipitate cardiovascular disease. Therefore, this study investigated the impact of bromocriptine treatment upon biomarkers of vascular oxidative/nitrosative stress (including the pro-oxidative/nitrosative stress enzymes of NADPH oxidase 4, inducible nitric oxide (iNOS), uncoupled endothelial nitric oxide synthase (eNOS), the pro-inflammatory/pro-oxidative marker GTP cyclohydrolase 1 (GTPCH 1), and the pro-vascular health enzyme, soluble guanylate cyclase (sGC) as well as the plasma level of thiobarbituric acid reactive substances (TBARS), a circulating marker of systemic oxidative stress), in hypertensive SHR rats held on a high fat diet to induce metabolic syndrome. Inasmuch as the central nervous system (CNS) dopaminergic activities both regulate and are regulated by CNS circadian pacemaker circuitry, this study also investigated the time-of-day-dependent effects of bromocriptine treatment (10 mg/kg/day at either 13 or 19 h after the onset of light (at the natural waking time or late during the activity period, respectively) among animals held on 14 h daily photoperiods for 16 days upon such vascular biomarkers of vascular redox state, several metabolic syndrome parameters, and mediobasal hypothalamic (MBH) mRNA expression levels of neuropeptides neuropeptide Y (NPY) and agouti-related protein (AgRP) which regulate the peripheral fuel metabolism and of mRNA expression of other MBH glial and neuronal cell genes that support such metabolism regulating neurons in this model system. Such bromocriptine treatment at ZT 13 improved (reduced) biomarkers of vascular oxidative/nitrosative stress including plasma TBARS level, aortic NADPH oxidase 4, iNOS and GTPCH 1 levels, and improved other markers of coupled eNOS function, including increased sGC protein level, relative to controls. However, bromocriptine treatment at ZT 19 produced no improvement in either coupled eNOS function or sGC protein level. Moreover, such ZT 13 bromocriptine treatment reduced several metabolic syndrome parameters including fasting insulin and leptin levels, as well as elevated systolic and diastolic blood pressure, insulin resistance, body fat store levels and liver fat content, however, such effects of ZT 19 bromocriptine treatment were largely absent versus control. Finally, ZT 13 bromocriptine treatment reduced MBH NPY and AgRP mRNA levels and mRNA levels of several MBH glial cell/neuronal genes that code for neuronal support/plasticity proteins (suggesting a shift in neuronal structure/function to a new metabolic control state) while ZT 19 treatment reduced only AgRP, not NPY, and was with very little effect on such MBH glial cell genes expression. These findings indicate that circadian-timed bromocriptine administration at the natural circadian peak of CNS dopaminergic activity (that is diminished in insulin resistant states), but not outside this daily time window when such CNS dopaminergic activity is naturally low, produces widespread improvements in biomarkers of vascular oxidative stress that are associated with the amelioration of metabolic syndrome and reductions in MBH neuropeptides and gene expressions known to facilitate metabolic syndrome. These results of such circadian-timed bromocriptine treatment upon vascular pathology provide potential mechanisms for the observed marked reductions in adverse cardiovascular events with circadian-timed bromocriptine-QR therapy (similarly timed to the onset of daily waking as in this study) of type 2 diabetes subjects and warrant further investigations into related mechanisms and the potential application of such intervention to prediabetes and metabolic syndrome patients as well.

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