The Relationship between the Gut Microbiome and Metformin as a Key for Treating Type 2 Diabetes Mellitus

Investigation of the relationship between inflammation and microbiota in the intestinal tissue of female and male rats fed with fructose: Modulatory role of metformin

BACKGROUND

It has been reported that High-Fructose (HF) consumption, considered one of the etiological factors of Metabolic Syndrome (MetS), causes changes in the gut microbiota and metabolic disorders. There is limited knowledge on the effects of metformin in HF-induced intestinal irregularities in male and female rats with MetS.

OBJECTIVES

In this study, we investigated the sex-dependent effects of metformin treatment on the gut microbiota, intestinal Tight Junction (TJ) proteins, and inflammation parameters in HF-induced MetS.

METHODS

Fructose was given to the male and female rats as a 20% solution in drinking water for 15 weeks. Metformin (200 mg/kg) was administered by gastric tube once a day during the final seven weeks. Biochemical, histopathological, immunohistochemical, and bioinformatics analyses were performed. Differences were considered statistically significant at p < 0.05.

RESULTS

The metformin treatment in fructose-fed rats promoted glucose, insulin, Homeostasis Model Assessment of Insulin Resistance Index (HOMA-IR), and Triglyceride (TG) values in both sexes. The inflammation score was significantly decreased with metformin treatment in fructose-fed male and female rats (p < 0.05). Moreover, metformin treatment significantly decreased Interleukin-1 Beta (IL-1β) and Tumor Necrosis Factor-Alpha (TNF-α) in ileum tissue from fructose-fed males (p < 0.05). Intestinal immunoreactivity of Occludin and Claudin-1 was increased with metformin treatment in fructose-fed female rats. HF and metformin treatment changed the gut microbial composition. Firmicutes/Bacteroidetes (F/B) ratio increased with HF in females. In the disease group, Bifidobacterium pseudolongum; in the treatment group, Lactobacillus helveticus and Lactobacillus reuteri are the prominent species in both sexes. When the male and female groups were compared, Akkermansia muciniphila was prominent in the male treatment group.

CONCLUSION

In conclusion, metformin treatment promoted biochemical parameters in both sexes of fructose-fed rats. Metformin showed a sex-dependent effect on inflammation parameters, permeability factors, and gut microbiota. Metformin has partly modulatory effects on fructose-induced intestinal changes.

Metformin-induced changes in the gut microbiome and plasma metabolome are associated with cognition in men

BACKGROUND

An altered gut microbiome characterized by reduced abundance of butyrate producing bacteria and reduced gene richness is associated with type 2 diabetes (T2D). An important complication of T2D is increased risk of cognitive impairment and dementia. The biguanide metformin is a commonly prescribed medication for the control of T2D and metformin treatment has been associated with a significant reduction in the risk of dementia and improved cognition, particularly in people with T2D.

AIM

To investigate the associations of metformin use with cognition exploring potential mechanisms by analyzing the gut microbiome and plasma metabolome using shotgun metagenomics and HPLC-ESI-MS/MS, respectively.

METHODS

We explored two independent cohorts: an observational study (Aging Imageomics) and a phase IV, randomized, double-blind, parallel-group, randomized pilot study (MEIFLO). From the two studies, we analyzed four study groups: (1) individuals with no documented medical history or medical treatment (n = 172); (2) people with long-term T2D on metformin monotherapy (n = 134); (3) people with long-term T2D treated with oral hypoglycemic agents other than metformin (n = 45); (4) a newly diagnosed T2D subjects on metformin monotherapy (n = 22). Analyses were also performed stratifying by sex.

RESULTS

Several bacterial species belonging to the Proteobacteria (Escherichia coli) and Verrucomicrobia (Akkermansia muciniphila) phyla were positively associated with metformin treatment, while bacterial species belonging to the Firmicutes phylum (Romboutsia timonensis, Romboutsia ilealis) were negatively associated. Due to the consistent increase in A. muciniphila and decrease in R.ilealis in people with T2D subjects treated with metformin, we investigated the association between this ratio and cognition. In the entire cohort of metformin-treated T2D subjects, the A.muciniphila/R.ilealis ratio was not significantly associated with cognitive test scores. However, after stratifying by sex, the A.muciniphila/R. ilealis ratio was significantly and positively associated with higher memory scores and improved memory in men. Metformin treatment was associated with an enrichment of microbial pathways involved in the TCA cycle, and butanoate, arginine, and proline metabolism in both cohorts. The bacterial genes involved in arginine metabolism, especially in production of glutamate (astA, astB, astC, astD, astE, putA), were enriched following metformin intake. In agreement, in the metabolomics analysis, metformin treatment was strongly associated with the amino acid proline, a metabolite involved in the metabolism of glutamate.

CONCLUSIONS

The beneficial effects of metformin may be mediated by changes in the composition of the gut microbiota and microbial-host-derived co-metabolites.

Effects of three Huanglian-derived polysaccharides on the gut microbiome and fecal metabolome of high-fat diet/streptozocin-induced type 2 diabetes mice

Plant-derived polysaccharides are important components for biological functions. The objective of this study is to study the mechanisms by which polysaccharides from three Huanglian (Rhizome Coptidis, HL) of Coptis chinensis, C. deltoidea, and Coptis teeta affect type 2 diabetes mellitus (T2DM) by analyzing the gut microbiome and their metabolites. A long-term high-fat diet (HFD) combined with streptozocin (STZ) induction was used to construct the T2DM mice model. The histopathology of liver, pancreas, and colon, biochemical indexes related to mice were determined to assess the ameliorative effects of these three HL polysaccharides (HLPs) on T2DM. The results indicated that oral HLPs improved hyperglycemia, insulin resistance, blood lipid levels, and β-cell function. Further, HLPs elevated the growth of advantageous beneficial bacteria within the gut microbiota and raised the concentrations of short-chain fatty acids (SCFAs), particularly butyric acid. Metabolic analyses showed that HLPs ameliorated the effects of T2DM on microbial-derived metabolites and related metabolic pathways, especially the biosynthetic pathways of phenylalanine, tyrosine, and tryptophan. In the combined analysis, many associations of T2DM-related biochemical indicators with gut microbes and their metabolites were extracted, which suggested the important role of gut microbiome and fecal metabolome in the amelioration of type 2 diabetes mellitus by HLPs.

Effect of metformin and metformin/linagliptin on gut microbiota in patients with prediabetes

Lifestyle modifications, metformin, and linagliptin reduce the incidence of type 2 diabetes (T2D) in people with prediabetes. The gut microbiota (GM) may enhance such interventions' efficacy. We determined the effect of linagliptin/metformin (LM) vs metformin (M) on GM composition and its relationship to insulin sensitivity (IS) and pancreatic β-cell function (Pβf) in patients with prediabetes. A cross-sectional study was conducted at different times: basal, six, and twelve months in 167 Mexican adults with prediabetes. These treatments increased the abundance of GM SCFA-producing bacteria M (Fusicatenibacter and Blautia) and LM (Roseburia, Bifidobacterium, and [Eubacterium] hallii group). We performed a mediation analysis with structural equation models (SEM). In conclusion, M and LM therapies improve insulin sensitivity and Pβf in prediabetics. GM is partially associated with these improvements since the SEM models suggest a weak association between specific bacterial genera and improvements in IS and Pβf.

Role of Synbiotics (Prebiotics and Probiotics) as Dietary Supplements in Type 2 Diabetes Mellitus Induced Health Complications

Diabetes is a metabolic disorder whose prevalence has become a worrying condition in recent decades. Chronic diabetes can result in serious health conditions such as impaired kidney function, stroke, blindness, and myocardial infarction. Despite a variety of currently available treatments, cases of diabetes and its complications are on the rise. This review article provides a comprehensive account of the ameliorative effect of prebiotics and probiotics individually or in combination i.e. synbiotics on health complications induced by Type 2 Diabetes Mellitus (T2DM). Recent advances in the field underscore encouraging outcomes suggesting the consumption of synbiotics leads to favorable changes in the gut microbiota. These changes result in the production of bioactive metabolites such as short-chain fatty acids (crucial for lowering blood sugar levels), reducing inflammation, preventing insulin resistance, and encouraging the release of glucagon-like peptide-1 in the host. Notably, novel strategies supplementing synbiotics to support gut microbiota are gaining attraction as pivotal interventions in mitigating T2DM-induced health complications. Thus, by nurturing a symbiotic relationship between prebiotics and probiotics i.e. synbiotics, these interventions hold promise in reshaping the microbial landscape of the gut thereby offering a multifaceted approach to managing T2DM and its associated morbidities. Supporting the potential of synbiotics underscores a paradigm shift toward holistic and targeted interventions in diabetes management, offering prospects for improved outcomes and enhanced quality of life for affected individuals. Nevertheless, more research needs to be done to better understand the single and multispecies pre/pro and synbiotics in the prevention and management of T2DM-induced health complications.

Imeglimin improves systemic metabolism by targeting brown adipose tissue and gut microbiota in obese model mice

Imeglimin is a recently developed anti-diabetic drug that could concurrently promote insulin secretion and insulin sensitivity, while its mechanisms of action are not fully understood. Here we show that imeglimin administration could protect mice from high fat diet-induced weight gain with enhanced energy expenditure and attenuated whitening of brown adipose tissue. Imeglimin administration led to significant alteration of gut microbiota, which included an increase of Akkermansia genus, with attenuation of obesity-associated gut pathologies. Ablation of microbiota by antibiotic treatment partially abrogated the insulin sensitizing effects of imeglimin, while not affecting its actions on body weight gain or brown adipose tissue. Collectively, our results characterize imeglimin as a potential agent promoting energy expenditure and gut integrity, providing new insights into its mechanisms of action.

New-Onset Diabetes Mellitus after Kidney Transplantation

New-Onset Diabetes Mellitus after Transplantation (NODAT) emerges as a prevalent complication post-kidney transplantation, with its incidence influenced by variations in NODAT definitions and follow-up periods. The condition's pathophysiology is marked by impaired insulin sensitivity and β-cell dysfunction. Significant risk factors encompass age, gender, obesity, and genetics, among others, with the use of post-transplant immunosuppressants intensifying the condition. NODAT's significant impact on patient survival and graft durability underscores the need for its prevention, early detection, and treatment. This review addresses the complexities of managing NODAT, including the challenges posed by various immunosuppressive regimens crucial for transplant success yet harmful to glucose metabolism. It discusses management strategies involving adjustments in immunosuppressive protocols, lifestyle modifications, and pharmacological interventions to minimize diabetes risk while maintaining transplant longevity. The importance of early detection and proactive, personalized intervention strategies to modify NODAT's trajectory is also emphasized, advocating for a shift towards more anticipatory post-transplant care.

Gut microbiota-derived gamma-aminobutyric acid from metformin treatment reduces hepatic ischemia/reperfusion injury through inhibiting ferroptosis

Hepatic ischemia/reperfusion injury (HIRI) is a common and inevitable factor leading to poor prognosis in various liver diseases, making the outcomes of current treatments in clinic unsatisfactory. Metformin has been demonstrated to be beneficial to alleviate HIRI in recent studies, however, the underpinning mechanism remains unclear. In this study, we found metformin mitigates HIRI-induced ferroptosis through reshaped gut microbiota in mice, which was confirmed by the results of fecal microbiota transplantation treatment but showed the elimination of the beneficial effects when gut bacteria were depleted using antibiotics. Detailedly, through 16S rRNA and metagenomic sequencing, we identified that the metformin-reshaped microbiota was characterized by the increase of gamma-aminobutyric acid (GABA) producing bacteria. This increase was further confirmed by the elevation of GABA synthesis key enzymes, glutamic acid decarboxylase and putrescine aminotransferase, in gut microbes of metformin-treated mice and healthy volunteers. Furthermore, the benefit of GABA against HIRI-induced ferroptosis was demonstrated in GABA-treated mice. Collectively, our data indicate that metformin can mitigate HIRI-induced ferroptosis by reshaped gut microbiota, with GABA identified as a key metabolite.

Metformin, Cognitive Function, and Changes in the Gut Microbiome

The decline in cognitive function and the prevalence of neurodegenerative disorders are among the most serious threats to health in old age. The prevalence of dementia has reached 50 million people worldwide and has become a major public health problem. The causes of age-related cognitive impairment are multiple, complex, and difficult to determine. However, type 2 diabetes (T2D) is linked to an enhanced risk of cognitive impairment and dementia. Human studies have shown that patients with T2D exhibit dysbiosis of the gut microbiota. This dysbiosis may contribute to the development of insulin resistance and increased plasma lipopolysaccharide concentrations. Metformin medication mimics some of the benefits of calorie restriction and physical activity, such as greater insulin sensitivity and decreased cholesterol levels, and hence may also have a positive impact on aging in humans. According to recent human investigations, metformin might partially restore gut dysbiosis related to T2D. Likewise, some studies showed that metformin reduced the risk of dementia and improved cognition, although not all studies are concordant. Therefore, this review focused on those human studies describing the effects of metformin on the gut microbiome (specifically the changes in taxonomy, function, and circulating metabolomics), the changes in cognitive function, and their possible bidirectional implications.

Advances in secondary prevention mechanisms of macrovascular complications in type 2 diabetes mellitus patients: a comprehensive review

Type 2 diabetes mellitus (T2DM) poses a significant global health burden. This is particularly due to its macrovascular complications, such as coronary artery disease, peripheral vascular disease, and cerebrovascular disease, which have emerged as leading contributors to morbidity and mortality. This review comprehensively explores the pathophysiological mechanisms underlying these complications, protective strategies, and both existing and emerging secondary preventive measures. Furthermore, we delve into the applications of experimental models and methodologies in foundational research while also highlighting current research limitations and future directions. Specifically, we focus on the literature published post-2020 concerning the secondary prevention of macrovascular complications in patients with T2DM by conducting a targeted review of studies supported by robust evidence to offer a holistic perspective.

Potential effects of the most prescribed drugs on the microbiota-gut-brain-axis: A review

The link between drug-induced dysbiosis and its influence on brain diseases through gut-residing bacteria and their metabolites, named the microbiota-gut-brain axis (MGBA), remains largely unexplored. This review investigates the effects of commonly prescribed drugs (metformin, statins, proton-pump-inhibitors, NSAIDs, and anti-depressants) on the gut microbiota, comparing the findings with altered bacterial populations in major brain diseases (depression, multiple sclerosis, Parkinson's and Alzheimer's). The report aims to explore whether drugs can influence the development and progression of brain diseases via the MGBA. Central findings indicate that all explored drugs induce dysbiosis. These dysbiosis patterns were associated with brain disorders. The influence on brain diseases varied across different bacterial taxa, possibly mediated by direct effects or through bacterial metabolites. Each drug induced both positive and negative changes in the abundance of bacteria, indicating a counterbalancing effect. Moreover, the above-mentioned drugs exhibited similar effects, suggesting that they may counteract or enhance each other's effects on brain diseases when taken together by comorbid patients. In conclusion, the interplay of bacterial species and their abundances may have a greater impact on brain diseases than individual drugs or bacterial strains. Future research is needed to better understand drug-induced dysbiosis and the implications for brain disease pathogenesis, with the potential to develop more effective therapeutic options for patients with brain-related diseases.

The effect of metformin combined with liraglutide on gut microbiota of Chinese patients with type 2 diabetes

BACKGROUND

Metformin (MET) is a first-line therapy for type-2 diabetes mellitus (T2DM). Liraglutide (LRG) is a glucagon-like peptide-1 receptor agonist used as a second-line therapy in combination with MET.

METHODS

We performed a longitudinal analysis comparing the gut microbiota of overweight and/or pre-diabetic participants (NCP group) with that of each following their progression to T2DM diagnosis (UNT group) using 16S ribosomal RNA gene sequencing of fecal bacteria samples. We also examined the effects of MET (MET group) and MET plus LRG (MET+LRG group) on the gut microbiota of these participants following 60 days of anti-diabetic drug therapy in two parallel treatment arms.

RESULTS

In the UNT group, the relative abundances of Paraprevotella (P = 0.002) and Megamonas (P = 0.029) were greater, and that of Lachnospira (P = 0.003) was lower, compared with the NCP group. In the MET group, the relative abundance of Bacteroides (P = 0.039) was greater, and those of Paraprevotella (P = 0.018), Blautia (P = 0.001), and Faecalibacterium (P = 0.005) were lower, compared with the UNT group. In the MET+LRG group, the relative abundances of Blautia (P = 0.005) and Dialister (P = 0.045) were significantly lower than in the UNT group. The relative abundance of Megasphaera in the MET group was significantly greater than in the MET+LRG group (P = 0.041).

CONCLUSIONS

Treatment with MET and MET+LRG results in significant alterations in gut microbiota, compared with the profiles of patients at the time of T2DM diagnosis. These alterations differed significantly between the MET and MET+LRG groups, which suggests that LRG exerted an additive effect on the composition of gut microbiota.

Bibliometrics and visual analysis of metformin and gut microbiota from 2012 to 2022: A systematic review

BACKGROUND

Metformin is an old drug used for the treatment of type 2 diabetes mellitus and can play a variety of roles by regulating the gut microbiota. The number of research articles on metformin in the gut microbiota has increased annually; however, no bibliometric tools have been used to analyze the research status and hot trends in this field. This study presents a bibliometric analysis of publications on metformin and gut microbiota.

METHODS

We searched the Web of Science core collection database on June 8, 2023, for papers related to metformin and gut microbiota from 2012 to 2022. We used Microsoft Excel 2021, VOSviewer1.6.19, CiteSpace 6.2.4, and R software package "bibliometrix" 4.0.0 to analyze the countries, institutions, authors, journals, citations, and keywords of the included publications.

RESULTS

We included 517 papers, and the trend in publications increased over the last 11 years. The 517 articles were from 57 countries, including 991 institutions and 3316 authors, and were published in 259 journals. China led all countries (233 papers) and the most influential institution was the Chinese Academy of Sciences (16 papers). PLOS ONE (19 papers) was the most popular journal, and Nature (1598 citations) was the most cited journal. Li and Kim were the 2 most published authors (six papers each), and Cani (272 co-citations) was the most co-cited author. "Metabolites," "aging," and "intestinal barrier" were emerging topics in this field.

CONCLUSIONS

This bibliometric study comprehensively summarizes the research trends and progress of metformin and gut microbiota, and provides new research topics and trends for studying the effects of metformin on gut microbiota in different diseases.

Changes in Oxidative Stress and Intestinal Permeability during Pregnancy in Women with Gestational Diabetes Mellitus Treated with Metformin or Insulin and Healthy Controls: A Randomized Controlled Trial

Both oxidative stress and intestinal permeability are increased in hyperglycemic situations and have been shown to be reduced by metformin in type 2 diabetes mellitus (T2DM) patients. The aim of this study was to elucidate the effect of metformin on oxidative stress and intestinal permeability in women with gestational diabetes mellitus (GDM) treated with metformin compared to those treated with insulin and healthy controls. A total of 120 women were included from August 2016 to February 2022: 41 received metformin (MET group), 38 received insulin (INS group), and 41 were healthy controls. Baseline and antenatal visits were carried out at 25.4 ± 4.8 and 36.1 ± 0.8 weeks of pregnancy, respectively. Advanced oxidation protein products (AOPPs), total antioxidant capacity (TAC), and zonulin levels were measured at every visit. Zonulin levels from baseline to prepartum visit increased significantly in both healthy controls (0.6 ± 0.9 to 1.2 ± 1.7 ng/mL, p = 0.004) and the INS group (0.4 ± 0.3 to 0.6 ± 0.5 ng/mL, p = 0.034) but did not significantly change in the MET group (0.4 ± 0.4 to 0.5 ± 0.4 ng/mL, p = 0.202). However, TAC and AOPP levels significantly increased in women with GDM, both in the INS and MET groups but not in the healthy controls. In conclusion, in our population, metformin has been shown to avoid an increase in intestinal permeability but failed to avoid an increase in oxidative stress related to hyperglycemia.

Restoring autophagic function: a case for type 2 diabetes mellitus drug repurposing in Parkinson's disease

Parkinson's disease (PD) is a predominantly idiopathic pathological condition characterized by protein aggregation phenomena, whose main component is alpha-synuclein. Although the main risk factor is ageing, numerous evidence points to the role of type 2 diabetes mellitus (T2DM) as an etiological factor. Systemic alterations classically associated with T2DM like insulin resistance and hyperglycemia modify biological processes such as autophagy and mitochondrial homeostasis. High glucose levels also compromise protein stability through the formation of advanced glycation end products, promoting protein aggregation processes. The ability of antidiabetic drugs to act on pathways impaired in both T2DM and PD suggests that they may represent a useful tool to counteract the neurodegeneration process. Several clinical studies now in advanced stages are looking for confirmation in this regard.

Drug and gut microbe relationships: Moving beyond antibiotics

Our understanding of drug-microbe relationships has evolved from viewing microbes as mere drug producers to a dynamic, modifiable system where they can serve as drugs or targets of precision pharmacology. This review highlights recent findings on the gut microbiome, particularly focusing on four aspects of research: (i) drugs for bugs, covering recent strategies for targeting gut pathogens; (ii) bugs as drugs, including probiotics; (iii) drugs from bugs, including postbiotics; and (iv) bugs and drugs, discussing additional types of drug-microbe interactions. This review provides a perspective on future translational research, including efficient companion diagnostics in pharmaceutical interventions.

Effects of metformin on the gut microbiota: A systematic review

BACKGROUND

The gut microbiota is increasingly recognized as a crucial factor in human health and disease. Metformin, a commonly prescribed medication for type 2 diabetes, has been studied for its potential impact on the gut microbiota in preclinical models. However, the effects of metformin on the gut microbiota in humans remain uncertain.

SCOPE OF REVIEW

We conducted a systematic review of clinical trials and observational studies to assess the existing knowledge on the impact of metformin on the gut microbiota in humans. The review focused on changes in bacterial composition and diversity following metformin treatment.

MAJOR CONCLUSIONS

Thirteen studies were included in the analysis. The results revealed alterations in the abundance of bacterial genera from various phyla, suggesting that metformin may selectively influence certain groups of bacteria in the gut microbiota. However, the effects on gut microbiota diversity were inconsistent across populations, with conflicting findings on changes in alpha and beta diversity measures. Overall, the use of metformin was associated with changes in the abundance of specific bacterial genera within the gut microbiota of human populations. However, the effects on gut microbiota diversity were not consistent, highlighting the need for further research to understand the underlying mechanisms and clinical significance of these changes.

UPLC-Q-TOF/MS-based metabonomics reveals mechanisms for Holothuria leucospilota polysaccharides (HLP)-regulated serum metabolic changes in diabetic rats

This study aimed to use metabolomic methods to explore how Holothuria leucospilota polysaccharides (HLP) improved metabolism disorders in the liver of Goto-Kakizaki (GK) rats with spontaneous type 2 diabetes. The results showed that HLP effectively improved the metabolic disorder. Based on KEGG functional analysis, five key biomarkers associated with bile acid metabolism were detected and screened (P < 0.05). The results of serum total bile acid levels and liver damage in diabetic rats further showed the regulatory effects of HLP on bile acid metabolism. The results of bile acid-related gene expression in the liver showed that HLP inhibited liver farnesoid X Receptor - small heterodimer partner (FXR-SHP) signalling and increased the expression of bile acid synthesis genes (P < 0.05). Our results explored the underlying mechanisms by which HLP accelerated cholesterol consumption to anti-hypercholesterolemia and anti-diabetic by inhibiting liver FXR-SHP signaling. HLP's effect on bile acid regulation provides insights into treating T2DM.

Unveiling the potential pleiotropic effects of metformin in treating COVID-19: a comprehensive review

This review article explores the potential of metformin, a medication commonly used for type 2 diabetes, as an antiviral and anti-inflammatory agent in the context of coronavirus disease 2019 (COVID-19). Metformin has demonstrated inhibitory effects on the growth of SARS-CoV-2 in cell culture models and has shown promising results in reducing viral load and achieving undetectable viral levels in clinical trials. Additionally, metformin exhibits anti-inflammatory properties by reducing the production of pro-inflammatory cytokines and modulating immune cell function, which may help prevent cytokine storms associated with severe COVID-19. The drug's ability to regulate the balance between pro-inflammatory Th17 cells and anti-inflammatory Treg cells suggests its potential in mitigating inflammation and restoring T cell functionality. Furthermore, metformin's modulation of the gut microbiota, particularly changes in bacterial taxa and the production of short-chain fatty acids, may contribute to its therapeutic effects. The interplay between metformin, bile acids, the gut microbiome, glucagon-like peptide-1 secretion, and glycemic control has implications for the management of diabetes and potential interventions in COVID-19. By refreshing the current evidence, this review highlights the potential of metformin as a therapeutic option in the management of COVID-19, while also exploring its effects on the gut microbiome and immunometabolism.

Metformin targets intestinal immune system signaling pathways in a high-fat diet-induced mouse model of obesity and insulin resistance

Introduction

Research findings of the past decade have highlighted the gut as the main site of action of the oral antihyperglycemic agent metformin despite its pharmacological role in the liver. Extensive evidence supports metformin's modulatory effect on the composition and function of gut microbiota, nevertheless, the underlying mechanisms of the host responses remain elusive. Our study aimed to evaluate metformin-induced alterations in the intestinal transcriptome profiles at different metabolic states.

Methods

The high-fat diet-induced mouse model of obesity and insulin resistance of both sexes was developed in a randomized block experiment and bulk RNA-Seq of the ileum tissue was the method of choice for comparative transcriptional profiling after metformin intervention for ten weeks.

Results

We found a prominent transcriptional effect of the diet itself with comparatively fewer genes responding to metformin intervention. The overrepresentation of immune-related genes was observed, including pronounced metformin-induced upregulation of immunoglobulin heavy-chain variable region coding Ighv1-7 gene in both high-fat diet and control diet-fed animals. Moreover, we provide evidence of the downregulation NF-kappa B signaling pathway in the small intestine of both obese and insulin-resistant animals as well as control animals after metformin treatment. Finally, our data pinpoint the gut microbiota as a crucial component in the metformin-mediated downregulation of NF-kappa B signaling evidenced by a positive correlation between the Rel and Rela gene expression levels and abundances of Parabacteroides distasonis, Bacteroides spp., and Lactobacillus spp. in the gut microbiota of the same animals.

Discussion

Our study supports the immunomodulatory effect of metformin in the ileum of obese and insulin-resistant C57BL/6N mice contributed by intestinal immunoglobulin responses, with a prominent emphasis on the downregulation of NF-kappa B signaling pathway, associated with alterations in the composition of the gut microbiome.

Targeting the gut microbiome to control drug pharmacomicrobiomics: the next frontier in oral drug delivery

INTRODUCTION

The trillions of microorganisms that comprise the gut microbiome form dynamic bidirectional interactions with orally administered drugs and host health. These relationships can alter all aspects of drug pharmacokinetics and pharmacodynamics (PK/PD); thus, there is a desire to control these interactions to maximize therapeutic efficacy. Attempts to modulate drug-gut microbiome interactions have spurred advancements within the field of 'pharmacomicrobiomics' and are poised to become the next frontier of oral drug delivery.

AREAS COVERED

This review details the bidirectional interactions that exist between oral drugs and the gut microbiome, with clinically relevant case examples outlining a clear motive for controlling pharmacomicrobiomic interactions. Specific focus is attributed to novel and advanced strategies that have demonstrated success in mediating drug-gut microbiome interactions.

EXPERT OPINION

Co-administration of gut-active supplements (e.g. pro- and pre-biotics), innovative drug delivery vehicles, and strategic polypharmacy serve as the most promising and clinically viable approaches for controlling pharmacomicrobiomic interactions. Targeting the gut microbiome through these strategies presents new opportunities for improving therapeutic efficacy by precisely mediating PK/PD, while mitigating metabolic disturbances caused by drug-induced gut dysbiosis. However, successfully translating preclinical potential into clinical outcomes relies on overcoming key challenges related to interindividual variability in microbiome composition and study design parameters.

Understanding the Role of the Gut Microbiome in Diabetes and Therapeutics Targeting Leaky Gut: A Systematic Review

The gut microbiota has been studied and continues to be a developing area in the pathognomic development of metabolic diseases like diabetes. Treatment with diet changes, the addition of supplements like prebiotics/probiotics, and the impact of fecal microbial transplantation can be correlated to targeting changes in dysbiosis. Understanding the impacts of various anti-hyperglycemic agents such as metformin and the implications of post-bariatric surgery on the gut microbiota diversity has emerged. These areas of study are crucial to understanding the pathognomic aspects of diabetes disease progression at the microbial level of metabolic and inflammatory mechanisms, which may give more insight into focusing on the role of diet prebiotic/probiotic supplements as potential forms of prospective management in diabetes and the development of more agents that target gut microbiota, which harbors low-grade inflammation. Intestinal dysbiosis was consistently observed in the mechanism of gut microbial change in diabetic individuals, contributing to reduced insulin sensitivity and poor glycemic control. This systematic review was carried out using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) 2020 checklist. We performed a literature search using the PubMed, Google Scholar and Science Direct databases in accordance with the eligibility criteria and ultimately selected 14 articles for final analysis. The Scale for the Assessment of Narrative Review Articles (SANRA) and the PRISMA 2020 checklist were used to assess the quality of selected articles for cross-sectional studies, traditional literature reviews, and systematic reviews, respectively. We collected papers from 2012 to 2022 for this review. We gathered articles from databases, such as this study, which show there is a strong connection between microbiota and diabetes that appears to exist. The objective is to assess and identify any dietary and therapeutic agents that may alter the microbiota and potentially target and modulate insulin sensitivity. This review article will discuss the pathophysiological effects of gut microbiota in diabetes management and the impact of various gut biodiversity therapeutics that can aid in reversing insulin sensitivity.

Effects of combined treatment of probiotics and metformin in management of Type 2 diabetes: A systematic review and meta-analysis

BACKGROUND

Lifestyle changes and dietary intervention, including the use of probiotics, can modulate dysbiosis of gut microbiome and contribute to the management of type 2 diabetes mellitus (T2DM). This systematic review and meta-analysis aim to assess the efficacy of metformin plus probiotics versus metformin alone on outcomes in patients with T2DM.

METHODS

We searched MEDLINE and EMBASE from inception to February 2023 to identify all randomized controlled trials (RCTs), which compared the use of metformin plus probiotics versus metformin alone in adult patients with T2DM. Data were summarized as mean differences (MD) with 95% confidence interval (CI) and pooled under the random effects model. Findings Fourteen RCTs (17 comparisons, 1009 patients) were included in this systematic review. Pooled results show a significant decrease in fasting glucose (FG) (MD=-0.64, 95% CI=-1.06, -0.22) and HbA1c (MD=-0.29, 95% CI=-0.47, -0.10) levels in patients with T2DM treated with metformin plus probiotics versus metformin alone. The addition of probiotics to metformin resulted in lower odds of gastrointestinal adverse events (Odds ratio=0.18, 95% CI=0.09, 0.3.8; I²=0%).

CONCLUSIONS

The addition of probiotics to metformin therapy is associated with improvement in T2DM outcomes. However, high-quality and adequately reported RCTs are needed in the future to confirm our findings.

Changes in the Gut Microbiota after the Use of Herbal Medicines in Overweight and Obese Individuals: A Systematic Review

BACKGROUND

Herbal medicine is a low-cost treatment and has been increasingly applied in obesity treatment. Gut microbiota (GM) is strongly associated with obesity pathogenesis.

METHODS

We conducted a systematic review guided by the question: "Does the use of herbal medicine change the GM composition in obese individuals?" Randomized clinical trials with obese individuals assessing the effects of herbal medicine intervention in GM were retrieved from the Medline, Embase, Scopus, Web of Science, and Cochrane Library databases, including the Cochrane Controlled Trials Register. Two reviewers independently extracted data using standardized piloted data extraction forms and assessed the study-level risk of bias using an Excel template of the Cochrane "Risk of bias" tool 2-RoB 2.

RESULTS

We identified 1094 articles in the databases. After removing duplicates and reading the title and abstract, 14 publications were fully evaluated, of which seven publications from six studies were considered eligible. The herbs analyzed were Moringa oleifera, Punica granatum, Scutellaria baicalensis, Schisandra chinensis, W-LHIT and WCBE. The analysis showed that Schisandra chinensis and Scutellaria baicalensis had significant effects on weight loss herbal intervention therapy composed by five Chinese herbal medicines Ganoderma lucidum, Coptis chinensis, Astragalus membranaceus, Nelumbo nucifera gaertn, and Fructus aurantii (W-LHIT) and white common bean extract (WCBE) on GM, but no significant changes in anthropometry and laboratory biomarkers.

CONCLUSIONS

Herbal medicine modulates GM and is associated with increased genera in obese individuals.

Detection and Quantification of Some Ethanol-Producing Bacterial Strains in the Gut of Mouse Model of Non-Alcoholic Fatty Liver Disease: Role of Metformin

Ethanol-producing dysbiotic gut microbiota could accelerate the progress of non-alcoholic fatty liver disease (NAFLD). Metformin demonstrated some benefits in NAFLD. In the present study, we tested the ability of metformin to modify ethanol-producing gut bacterial strains and, consequently, retard the progress of NAFLD. This 12-week study included forty mice divided into four groups (n = 10); normal diet, Western diet, Western diet with intraperitoneal metformin, and Western diet with oral metformin. Oral metformin has a slight advantage over intraperitoneal metformin in ameliorating the Western diet-induced changes in liver function tests and serum levels of different cytokines (IL-1β, IL-6, IL-17, and TNF-α). Changes in liver histology, fibrosis, lipid content, Ki67, and TNF-α were all corrected as well. Faecal ethanol contents were increased by the Western diet but did not improve after treatment with metformin although the numbers of ethanol-producing Klebsiella pneumoniae (K. pneumoniae) and Escherichia coli (E. coli) were decreased by oral metformin. Metformin did not affect bacterial ethanol production. It does not seem that modification of ethanol-producing K. pneumoniae and E. coli bacterial strains by metformin could have a significant impact on the therapeutic potentials of metformin in this experimental model of NAFLD.

The Effects of Cardioprotective Antidiabetic Therapy on Microbiota in Patients with Type 2 Diabetes Mellitus-A Systematic Review

As the pathophysiologic mechanisms of type 2 diabetes mellitus (T2DM) are discovered, there is a switch from glucocentric to a more comprehensive, patient-centered management. The holistic approach considers the interlink between T2DM and its complications, finding the best therapies for minimizing the cardiovascular (CV) or renal risk and benefitting from the treatment's pleiotropic effects. Sodium-glucose cotransporter 2 inhibitors (SGLT-2i) and glucagon-like peptide-1 receptor agonists (GLP-1 RA) fit best in the holistic approach because of their effects in reducing the risk of CV events and obtaining better metabolic control. Additionally, research on the SGLT-2i and GLP-1 RA modification of gut microbiota is accumulating. The microbiota plays a significant role in the relation between diet and CV disease because some intestinal bacteria lead to an increase in short-chain fatty acids (SCFA) and consequent positive effects. Thus, our review aims to describe the relation between antidiabetic non-insulin therapy (SGLT-2i and GLP-1 RA) with CV-proven benefits and the gut microbiota in patients with T2DM. We identified five randomized clinical trials including dapagliflozin, empagliflozin, liraglutide, and loxenatide, with different results. There were differences between empagliflozin and metformin regarding the effects on microbiota despite similar glucose control in both study groups. One study demonstrated that liraglutide induced gut microbiota alterations in patients with T2DM treated initially with metformin, but another failed to detect any differences when the same molecule was compared with sitagliptin. The established CV and renal protection that the SGLT-2i and GLP-1 RA exert could be partly due to their action on gut microbiota. The individual and cumulative effects of antidiabetic drugs on gut microbiota need further research.

Changes in the Microbiota and their Roles in Patients with Type 2 Diabetes Mellitus

An association between type 2 diabetes mellitus (T2DM) and gut microbiota is well established, but the results of related studies are inconsistent. The purpose of this investigation is to elucidate the characteristics of the gut microbiota in T2DM and non-diabetic subjects. Forty-five subjects were recruited for this study, including 29 T2DM patients and 16 non-diabetic subjects. Biochemical parameters, including body mass index (BMI), fasting plasma glucose (FPG), serum total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), and hemoglobin A1c (HbA1c), were analyzed and correlated with the gut microbiota. Bacterial community composition and diversity were detected in fecal samples using direct smear, sequencing, and real-time polymerase chain reaction (PCR). In this study, it was observed that indicators such as BMI, FPG, HbA1c, TC, and TG in T2DM patients were on the rise, concurrent with dysbiosis of the microbiota. We observed an increase in Enterococci and a decrease in Bacteroides, Bifidobacteria, and Lactobacilli in patients with T2DM. Meanwhile, total short-chain fatty acids (SCFAs) and D-lactate concentrations were decreased in the T2DM group. In addition, FPG was positively correlated with Enterococcus and negatively correlated with Bifidobacteria, Bacteroides, and Lactobacilli. This study reveals that microbiota dysbiosis is associated with disease severity in patients with T2DM. The limitation of this study is that only common bacteria were noted in this study, and more in-depth related studies are urgently needed.

Identification of Gut Microbial Lysine and Histidine Degradation and CYP-Dependent Metabolites as Biomarkers of Fatty Liver Disease

Numerous studies have described specific metabolites as biomarkers of severe liver diseases, but very few have measured gut microbiota (GM)-produced metabolites in fatty liver disease. We aimed at finding GM signatures and metabolite markers in plasma and feces related to high liver fat content. Based on imaging, we divided study participants into low (<5%, LF, n = 25) and high (>5%, HF, n = 39) liver fat groups. Fecal (LF n = 14, HF n = 25) and plasma (LF n = 11, HF n = 7) metabolomes of subsets of participants were studied using liquid chromatography/high resolution mass spectrometry. The GM were analyzed using 16S rRNA gene sequencing. Additionally, blood clinical variables and diet were studied. Dyslipidemia, higher liver enzymes and insulin resistance characterized the HF group. No major differences in diet were found between the groups. In the GM, the HF group had lower abundance of Bacteroides and Prevotellaceae NK3B31 group than the LF group after adjusting for metformin use or obesity. In feces, the HF group had higher levels of lysine and histidine degradation products, while 6-hydroxybetatestosterone (metabolized by CYP3A4) was low. Higher plasma levels of caffeine and its metabolites in the HF group indicate that the activity of hepatic CYP1A2 was lower than in the LF group. Our results suggest, that low fecal Prevotellaceae NK3B31 and Bacteroides abundance, and increased lysine and histidine degradation may serve as GM biomarkers of high liver fat. Altered plasma caffeine metabolites and lowered testosterone metabolism may specify decreased CYP activities, and their potential utility, as biomarkers of fatty liver disease. IMPORTANCE Because the high prevalence of nonalcoholic fatty liver disease sets diagnostic challenges to health care, identification of new biomarkers of the disease that in the future could have potential utility as diagnostic biomarkers of high liver fat content is important. Our results show that increased amino acid degradation products in the feces may be such biomarkers. In the blood, molecules that indicate defective hepatic metabolic enzyme activities were identified in individuals with high liver fat content.

Sex-Related Effects of Gut Microbiota in Metabolic Syndrome-Related Diabetic Retinopathy

The metabolic syndrome (MetS) is a complex disease of metabolic abnormalities, including obesity, insulin resistance, hypertension and dyslipidaemia, and it is associated with an increased risk of cardiovascular disease (CVD). Diabetic retinopathy (DR) is the leading cause of vision loss among working-aged adults around the world and is the most frequent complication in type 2 diabetic (T2D) patients. The gut microbiota are a complex ecosystem made up of more than 100 trillion of microbial cells and their composition and diversity have been identified as potential risk factors for the development of several metabolic disorders, including MetS, T2D, DR and CVD. Biomarkers are used to monitor or analyse biological processes, therapeutic responses, as well as for the early detection of pathogenic disorders. Here, we discuss molecular mechanisms underlying MetS, the effects of biological sex in MetS-related DR and gut microbiota, as well as the latest advances in biomarker research in the field. We conclude that sex may play an important role in gut microbiota influencing MetS-related DR.

The gut microbiota pathway mechanisms of diabetes

The contribution of dysbiotic gut microbiota configuration is essential when making reference to the metabolic disorders by increasing energy. It is important to understand that the gut microbiota induced metabolic disease mechanisms and inflammations. Thus it is imperative to have an insight into the state of all chronic subclinical inflammations influencing disease outcomes. However, from the emerging studies, there still exist inconsistencies in the findings of such studies. While making the best out of the reasons for inconsistencies of the findings, this review is designed to make a clear spell out as to the inconsistence of gut microbiota with respect to diabetes. It considered gut-virome alterations and diabetes and gut-bacteriome-gut-virome-alterations and diabetes as confounding factors. The review further explained some study design strategies that will spontaneously eliminate any potential confounding factors to lead to a more evidence based diabetic-gut microbiota medicine. Lipopolysaccharide (LPS) pro-inflammatory, metabolic endotoxemia and diet/gut microbiota insulin-resistance and low-grade systemic inflammation induced by gut microbiota can trigger pro-inflammatory cytokines in insulin-resistance, consequently, leading to the diabetic condition. While diet influences the gut microbiota, the consequences are mainly the constant high levels of pro-inflammatory cytokines in the circulatory system. Of recent, dietary natural products have been shown to be anti-diabetic. The effects of resveratrol on the gut showed an improved lipid profile, anti-inflammatory properties and ameliorated the endotoxemia, tight junction and glucose intolerance.

Therapeutic efficacy of liraglutide versus metformin in modulating the gut microbiota for treating type 2 diabetes mellitus complicated with nonalcoholic fatty liver disease

Metformin and liraglutide are used in the treatment of type 2 diabetes mellitus (T2DM) complicated with nonalcoholic fatty liver disease (NAFLD). Although these drugs can alter the intestinal microbiome, clinical data are required to explore their mechanisms of action. Using 16S sequencing technology, we analyzed and compared the intestinal bacterial community structure and function between patients before and after treatment (12 weeks) with the two drugs (metformin or liraglutide, n = 15) and healthy controls (n = 15). Moreover, combined with 19 clinical indices, the potential therapeutic mechanisms of the two drugs were compared. The studied clinical indices included those associated with islet β-cell function (FPG, FINS, HbA1c, and HOMA-IR), inflammation (TNF-α, IL-6, and APN), lipid metabolism (TC, TG, and LDL-C), and liver function (ALT, AST, and GGT); the values of all indices changed significantly after treatment (p < 0.01). In addition, the effect of the two drugs on the intestinal bacterial community varied. Liraglutide treatment significantly increased the diversity and richness of the intestinal bacterial community (p < 0.05); it significantly increased the relative abundances of Bacteroidetes, Proteobacteria, and Bacilli, whereas metformin treatment significantly increased the relative abundance of Fusobacteria and Actinobacteria (p < 0.05). Metformin treatment increased the complexity and stability of the intestinal bacterial network. However, liraglutide treatment had a weaker effect on the intestinal bacterial network, and the network after treatment was similar to that in healthy controls. Correlation matrix analysis between dominant genera and clinical indicators showed that the correlation between the bacterial community and islet β-cell function was stronger after liraglutide treatment, whereas the correlation between the bacterial community and inflammation-related factors was stronger after metformin treatment. Functional prediction showed that liraglutide could significantly affect the abundance of functional genes related to T2DM and NAFLD (p < 0.05), but the effect of metformin was not significant. This study is the first to report the changes in the intestinal bacterial community in patients treated with metformin or liraglutide and the differences between the mechanisms of action of metformin and liraglutide. Metformin or liraglutide has a therapeutic value in T2DM complicated with NAFLD, with liraglutide having a weaker effect on the intestinal bacterial community but a better therapeutic efficacy.

The role and mechanism of the gut microbiota in the development and treatment of diabetic kidney disease

Diabetic kidney disease (DKD) is a common complication in patients with diabetes mellitus (DM). Increasing evidence suggested that the gut microbiota participates in the progression of DKD, which is involved in insulin resistance, renin-angiotensin system (RAS) activation, oxidative stress, inflammation and immunity. Gut microbiota-targeted therapies including dietary fiber, supplementation with probiotics or prebiotics, fecal microbiota transplantation and diabetic agents that modulate the gut microbiota, such as metformin, glucagon-like peptide-1 (GLP-1) receptor agonists, dipeptidyl peptidase-4 (DPP-4) inhibitors, and sodium-glucose transporter-2 (SGLT-2) inhibitors. In this review, we summarize the most important findings about the role of the gut microbiota in the pathogenesis of DKD and the application of gut microbiota-targeted therapies.

Relationships between Diabetes and the Intestinal Microbial Population

Diabetes is a metabolic disorder characterized by lower responsiveness of tissues to insulin and consequent large variations in circulating levels of glucose. This fluctuation has harmful effects as both hyperglycemia and hypoglycemia can be very injurious. The causes of diabetes are varied but the consequences are rather uniform. Dietary factors are important especially in adult onset type 2 diabetes (T2D) while type 1 diabetes (T1D) is characterized by having a stronger heritable component and involving autoimmune attach on pancreatic beta cells. This review is focused on the relation of the bacterial components found within the intestine, to the establishment and maintenance of diabetes. The precise composition of the gut microbiome is increasingly recognized as a factor in organismic health and its interaction with a variety of disease states has been described. This is especially marked in the case of diabetes since the nature of the diet is an important factor in establishing both the microbiome and the incidence of diabetes. The bidirectional nature of this relationship is discussed. The effects of disease that lead to altered microbiomal composition together with aberrant metabolic changes are also included. Emphasis is given to the important role of short chain fatty acids (SCFAs) as mediators of the microbiome-diabetes relation.

Metformin in therapeutic applications in human diseases: its mechanism of action and clinical study

Metformin, a biguanide drug, is the most commonly used first-line medication for type 2 diabetes mellites due to its outstanding glucose-lowering ability. After oral administration of 1 g, metformin peaked plasma concentration of approximately 20-30 μM in 3 h, and then it mainly accumulated in the gastrointestinal tract, liver and kidney. Substantial studies have indicated that metformin exerts its beneficial or deleterious effect by multiple mechanisms, apart from AMPK-dependent mechanism, also including several AMPK-independent mechanisms, such as restoring of redox balance, affecting mitochondrial function, modulating gut microbiome and regulating several other signals, such as FBP1, PP2A, FGF21, SIRT1 and mTOR. On the basis of these multiple mechanisms, researchers tried to repurpose this old drug and further explored the possible indications and adverse effects of metformin. Through investigating with clinical studies, researchers concluded that in addition to decreasing cardiovascular events and anti-obesity, metformin is also beneficial for neurodegenerative disease, polycystic ovary syndrome, aging, cancer and COVID-19, however, it also induces some adverse effects, such as gastrointestinal complaints, lactic acidosis, vitamin B12 deficiency, neurodegenerative disease and offspring impairment. Of note, the dose of metformin used in most studies is much higher than its clinically relevant dose, which may cast doubt on the actual effects of metformin on these disease in the clinic. This review summarizes these research developments on the mechanism of action and clinical evidence of metformin and discusses its therapeutic potential and clinical safety.

Type 2 Diabetes and the Microbiome

Diabetes represents one of the most significant, and rapidly escalating, global healthcare crises we face today. Diabetes already affects one-tenth of the world's adults-more than 537 million people, numbers that have tripled since 2000 and are estimated to reach 643 million by 2030. Type 2 diabetes (T2D), the most prevalent form, is a complex disease with numerous contributing factors, including genetics, epigenetics, diet, lifestyle, medication use, and socioeconomic factors. In addition, the gut microbiome has emerged as a significant potential contributing factor in T2D development and progression. Gut microbes and their metabolites strongly influence host metabolism and immune function, and are now known to contribute to vitamin biosynthesis, gut hormone production, satiety, maintenance of gut barrier integrity, and protection against pathogens, as well as digestion and nutrient absorption. In turn, gut microbes are influenced by diet and lifestyle factors such as alcohol and medication use, including antibiotic use and the consumption of probiotics and prebiotics. Here we review current evidence regarding changes in microbial populations in T2D and the mechanisms by which gut microbes influence glucose metabolism and insulin resistance, including inflammation, gut permeability, and bile acid production. We also explore the interrelationships between gut microbes and different T2D medications and other interventions, including prebiotics, probiotics, and bariatric surgery. Lastly, we explore the particular role of the small bowel in digestion and metabolism and the importance of studying small bowel microbes directly in our search to find metabolically relevant biomarkers and therapeutic targets for T2D.

Unique Pakistani gut microbiota highlights population-specific microbiota signatures of type 2 diabetes mellitus

Biogeographic variations in the gut microbiota are pivotal to understanding the global pattern of host-microbiota interactions in prevalent lifestyle-related diseases. Pakistani adults, having an exceptionally high prevalence of type 2 diabetes mellitus (T2D), are one of the most understudied populations in microbiota research to date. The aim of the present study is to examine the gut microbiota across individuals from Pakistan and other populations of non-industrialized and industrialized lifestyles with a focus on T2D. The fecal samples from 94 urban-dwelling Pakistani adults with and without T2D were profiled by bacterial 16S ribosomal RNA gene and fungal internal transcribed spacer (ITS) region amplicon sequencing and eubacterial qPCR, and plasma samples quantified for circulating levels of lipopolysaccharide-binding protein (LBP) and the activation ability of Toll-like receptor (TLR)-signaling. Publicly available datasets generated with comparable molecular methods were retrieved for comparative analysis of the bacterial microbiota. Overall, urbanized Pakistanis' gut microbiota was similar to that of transitional or non-industrialized populations, depleted in Akkermansiaceae and enriched in Prevotellaceae (dominated by the non-Westernized clades of Prevotella copri). The relatively high proportion of Atopobiaceae appeared to be a unique characteristic of the Pakistani gut microbiota. The Pakistanis with T2D had elevated levels of LBP and TLR-signaling in circulation as well as gut microbial signatures atypical of other populations, e.g., increased relative abundance of Libanicoccus/Parolsenella, limiting the inter-population extrapolation of gut microbiota-based classifiers for T2D. Taken together, our findings call for a more global representation of understudied populations to extend the applicability of microbiota-based diagnostics and therapeutics.

Integrated Analysis of the Fecal Metagenome and Metabolome in Bladder Cancer in a Chinese Population

Bladder cancer (BLCA) is a common malignancy of the urinary system. The gut microbiome produces various metabolites that play functional roles in tumorigenesis and tumor progression. However, the integrative analysis of the gut microbiome and metabolome in BLCA has still been lacking. Thus, the aim of this study was to identify microbial and functional characteristics and metabolites in BLCA in a Chinese population. Metagenomics, targeted metabolomics, bioinformatics, and integrative analysis were used in fecal samples of BLCA patients and healthy individuals. We found gut microbiomes were significantly dysregulated in BLCA patients, including Bifidobacterium, Lactobacillus, Streptococcus, Blautia, and Eubacterium. We also found 11Z-eicosenoic acid, 3-methoxytyrosine, abrine, aniline-2-sulfonate, arachidic acid, conjugated linoleic acids, elaidic acid, glycylleucine, glycylproline, leucyl-glycine, linoelaidic acid, linoleic acid, nicotinamide hypoxanthine dinucleotide, oleic acid, petroselinic acid, and ricinoleic acid to be significantly decreased, while cholesterol sulfate was significantly increased in BLCA patients. Integration of metagenomics and metabolomics revealed interactions between gut microbiota and metabolites and the host. We identified the alterations of gut microbiomes and metabolites in BLCA in a Chinese population. Moreover, we preliminarily revealed the associations between specific gut microbiomes and metabolites. These findings determined potential causative links among gut dysbiosis, dysregulated metabolites, and BLCA.

Changing Patterns of Antihyperglycaemic Treatment among Patients with Type 2 Diabetes in Hungary between 2015 and 2020-Nationwide Data from a Register-Based Analysis

Background and objectives: In the last couple of years, pharmacological management of patients with type 2 diabetes mellitus (T2DM) have been markedly renewed. The aim of this study was to analyse the changes in prescribing patterns of antidiabetic drugs for treating patients with T2DM in Hungary between 2015 and 2020. Material and Methods: In this retrospective, nationwide analysis, we used the central database of the National Health Insurance Fund. We present annual numbers and their proportion of T2DM patients with different treatment regimens. Results: In the period of 2015−2020, the number of incident cases decreased from 60,049 to 29,865, while prevalent cases increased from 682,274 to 752,367. Patients with metformin (MET) monotherapy had the highest prevalence (31% in 2020). Prevalence of insulin (INS) monotherapy continuously but slightly decreased from 29% to 27% while that of sulfonylurea (SU) monotherapy markedly decreased from 37% to 20%. Dipeptidyl peptidase (DPP-4) inhibitors remained popular in 2020 as monotherapy (5%), in dual combination with MET (12%) and in triple combination with MET and SU (5%). The prevalence of patients with sodium-glucose co-transporter-2 (SGLT-2) inhibitors increased from 1% to 4% in monotherapy, from <1% to 6% in dual combination with MET, and from <1% to 2% in triple oral combination with MET and SU or DPP-4-inhibitors. The prevalence of patients using glucagon-like peptide-1 receptor agonists (GLP-1-RAs) also increased but remained around 1−2% both in monotherapy and combinations. For initiating antihyperglycaemic treatment, MET monotherapy was the most frequently used regime in 2020 (50%), followed by monotherapy with SUs (16%) or INS (10%). After initial MET monotherapy, the incidence rates of patients with add-on GLP-1-RAs (2%, 3%, and 4%) and those of add-on SGLT-2 inhibitors (4%, 6%, and 8%) slowly increased in the subsequent 24, 48, and 72 months, respectively. Conclusions: In the period of 2015−2020, we documented important changes in trends of antihyperglycaemic therapeutic patterns in patients with T2DM which followed the new scientific recommendations but remained below our expectations regarding timing and magnitude. More efforts are warranted to implement new agents with cardiovascular/renal benefits into therapeutic management in time, in a much larger proportion of T2DM population, and without delay.

Alternative to Sugar, Honey Does Not Provoke Insulin Resistance in Rats Based on Lipid Profiles, Inflammation, and IRS/PI3K/AKT Signaling Pathways Modulation

Insulin resistance (IR) is the central link to metabolic syndrome (MS), and IR prevention has become the key to overcoming this worldwide public health problem. A diet rich in simple sugars is an important pathogenic factor in IR development. To investigate the effect of honey on IR compared to the sugar-water diet, we analyzed phenolics and oligosaccharides in jujube honey and rape honey based on LC-MS and silane derivatization/GC-MS. The effects of different diets on glucose and lipid profile, histopathology and IR-related mechanism pathways were analyzed and compared by equal sugar levels intervention of fructose, fructose + glucose and two kinds of unifloral honey (high-/low-dose) in rats. The results suggested that sugar-equivalent honey, which differs from sugar solution, especially 17.1 g/kg BW jujube honey rich in phenolics (1.971 mg/100 g of isoquercitrin) and oligosaccharides (2.18 g/100 g of turanose), suppressed IR via maintaining glucose (OGTT and ITT) and lipid (TC, TG, LDL-C, HDL-C, and NEFA) homeostasis, improving histological structural abnormalities of the liver, adipose and skeletal muscle, reducing oxidative stress (GSH-Px and MDA) and inflammation (IL-6 and TNF-α), modulating the NF-κB (NF-κB gene expression was down-regulated to 0.94) and IRS/PI3K/AKT signaling pathways (e.g., AKT and GLUT2 expression in liver increased by 4.56 and 13.37 times, respectively) as well as reshaping the gut microbiota. These revealed a potential nutritional contribution of substituting honey for simple sugar in the diet, providing a theoretical basis for controlling IR development via dietary modification and supplementation.

Synbiotics and Gut Microbiota: New Perspectives in the Treatment of Type 2 Diabetes Mellitus

The number of people with type 2 diabetes mellitus (T2DM) has increased sharply over the past decades. Apart from genetic predisposition, which may cause some of the diagnosed cases, an unhealthy diet and lifestyle are incentive triggers of this global epidemic. Consumption of probiotics and prebiotics to gain health benefits has become increasingly accepted by the public in recent years, and their critical roles in alleviating T2DM symptoms are confirmed by accumulating studies. Microbiome research reveals gut colonization by probiotics and their impacts on the host, while oral intake of prebiotics may stimulate existing metabolisms in the colon. The use of synbiotics (a combination of prebiotics and probiotics) can thus show a synergistic effect on T2DM through modulating the gastrointestinal microenvironment. This review summarizes the research progress in the treatment of T2DM from the perspective of synbiotics and gut microbiota and provides a class of synbiotics which are composed of lactulose, arabinose, and Lactobacillus plantarum, and can effectively adjust the blood glucose, blood lipid, and body weight of T2DM patients to ideal levels.

Factors Determining Effective Probiotic Activity: Evaluation of Survival and Antibacterial Activity of Selected Probiotic Products Using an "In Vitro" Study

There are many different probiotic products on the market. Are they all equally effective? What criteria should a probiotic formulation meet to provide the most benefit to the patient? The current research aims to evaluate the parameters that influence the effectiveness of market probiotic products. These properties are critical for restoring eubiosis in patients with drug-induced dysbiosis or other pathological conditions, which could be caused by stress, wrong eating. Methods: The disintegration time of probiotic capsules in hydrochloric acid was investigated using a disintegration testing device. The survival rate of probiotic preparations in hydrochloric acid at pH 2 and in a 0.4% bile solution was then evaluated. For this purpose, the number of bacteria before and after incubation in the respective solutions was determined using the plate method. Inhibition of gastrointestinal pathogens by the probiotic products was determined using the Strus bar graph method. The highest survival rate of probiotic bacteria at low pH is shown by preparations produced in the form of acid-resistant capsules. Conclusions: The most important factor determining the good survival of bacterial strains under conditions simulating the gastrointestinal tract is the type of capsule used for their production and storage. The best antimicrobial activity against most common human gastrointestinal pathogens such as Eschericha coli, Shigella, Salmonella spp., Clostridioides difficile (the largest inhibition zones) are shown by probiotic products with the greatest diversity of bacterial strains.

Reactive Oxygen Species/Reactive Nitrogen Species as Messengers in the Gut: Impact on Physiology and Metabolic Disorders

Significance: The role of reactive oxygen/nitrogen species as "friend" or "foe" messengers in the whole body is well characterized. Depending on the concentration in the tissue considered, these molecular actors exert beneficial or deleterious impacts leading to a pathological state, as observed in metabolic disorders such as type 2 diabetes and obesity. Recent Advances: Among the tissues impacted by oxidation and inflammation in this pathological state, the intestine is a site of dysfunction that can establish diabetic symptoms, such as alterations in the intestinal barrier, gut motility, microbiota composition, and gut/brain axis communication. In the intestine, reactive oxygen/nitrogen species (from the host and/or microbiota) are key factors that modulate the transition from physiological to pathological signaling. Critical Issues: Controlling the levels of intestinal reactive oxygen/nitrogen species is a complicated balance between positive and negative impacts that is in constant equilibrium. Here, we describe the synthesis and degradation of intestinal reactive oxygen/nitrogen species and their interactions with the host. The development of novel redox-based therapeutics that alter these processes could restore intestinal health in patients with metabolic disorders. Future Directions: Deciphering the mode of action of reactive oxygen/nitrogen species in the gut of obese/diabetic patients could result in a future therapeutic strategy that combines nutritional and pharmacological approaches. Consequently, preventive and curative treatments must take into account one of the first sites of oxidative and inflammatory dysfunctions in the body, that is, the intestine. Antioxid. Redox Signal. 37, 394-415.

Does the Gut Microbiome Play a Role in Obesity in Type 1 Diabetes? Unanswered Questions and Review of the Literature

Evidence suggests that type 1 diabetes (T1D) risk and progression are associated with gut bacterial imbalances. Children with either T1D or islet antibody positivity exhibit gut dysbiosis (microbial imbalance) characterized by lower gram-positive to gram-negative gut bacterial ratios compared to healthy individuals, leading to a pro-inflammatory milieu. In addition, specific gut microbiome changes, including increased virulence factors, elevated phage, prophage, and motility genes, and higher amplitude stress responses, have been identified in individuals who have or are progressing towards T1D. Additionally, gut microbiome differences are associated with and thought to contribute to obesity, a comorbidity that is increasingly prevalent among persons with T1D. Obesity in T1D is problematic because individuals with obesity progress faster to T1D, have reduced insulin sensitivity compared to their lean counterparts, and have higher risk of complications. Animal and human studies suggest higher relative abundance of bacterial taxa associated with changes in bile acid and short chain fatty acid biosynthesis in obesity. However, it is unknown to what extent the gut microbiome plays a role in obesity in T1D and these worse outcomes. In this review, we aim to evaluate potential gut microbiome changes and associations in individuals with T1D who are obese, highlighting the specific gut microbiome changes associated with obesity and with T1D development. We will identify commonalities and differences in microbiome changes and examine potential microbiota-host interactions and the metabolic pathways involved. Finally, we will explore interventions that may be of benefit to this population, in order to modify disease and improve outcomes.

Reduced Cytokine Tumour Necrosis Factor by Pharmacological Intervention in a Preclinical Study

Recent preclinical studies in our laboratory have shown that the bile acid profile is altered during diabetes development and such alteration has been linked to the diabetes-associated inflammatory profile. Hence, this study aimed to investigate if the first-line antidiabetic drug metformin will alter the bile acid profile and diabetes-associated inflammation in a murine model of pre-type 2 diabetes. C57 mice were randomly allocated into three equal groups of eight. Group One was given a low-fat diet (LFD), Group Two was given a high-fat diet (HFD), and Group Three was given an HFD and, upon prediabetes confirmation, daily oral metformin for one month. Blood glucose, glycated haemoglobin, drug concentrations in tissues and faeces, and the inflammatory and bile acid profiles were measured. Metformin showed wide tissue distribution and was also present in faeces. The bile acid profile showed significant alteration due to prediabetes, and although metformin did not completely normalize it, it did exert significant effects on both the bile acid and the inflammatory profiles, suggesting a direct and, to some extent, positive impact, particularly on the diabetes-associated inflammatory profile.

Metformin Influence on the Intestinal Microbiota and Organism of Rats with Metabolic Syndrome

Metformin is a first-line drug for DM2 treatment and prevention, but its complex effect on impaired glucose tolerance (IGT), including its influence on myocardial resistance to ischemia-reperfusion injury, is not completely studied. We aimed to evaluate the influence of metformin on the intestinal microbiota (IM), metabolism, and functional and morphological characteristics of myocardium in rats with IGT. IGT was modelled in SPF Wistar rats with a high-fat diet and streptozotocin and nicotinamide injection. Rats were divided into three groups: IGT (without treatment), IGT MET (metformin therapy), and CRL (without IGT induction and treatment). IGT group was characterized by: higher body weight, increased serum glucose and total cholesterol levels, atherogenic coefficient, impairment in the functional parameters of the isolated heart during perfusion, and larger myocardium infarction (MI) size in comparison with the CRL group. IM of IGT rats differed from that of CRL: an increase of Bacteroides, Acinetobacter, Akkermansia, Roseburia, and a decrease of Lactobacillus genera representation. Metformin therapy led to the diminishing of metabolic syndrome (MS) symptoms, which correlated with IM restoration, especially with the growth of Akkermansia spp. and decline of Roseburia populations and their influence on other members of IM. The obtained results allow us to consider from a new point of view the expediency of probiotic A. muciniphila use for MS treatment.

The role of AMPK-dependent pathways in cellular and molecular mechanisms of metformin: a new perspective for treatment and prevention of diseases

Metformin can suppress gluconeogenesis and reduce blood sugar by activating adenosine monophosphate-activated protein kinase (AMPK) and inducing small heterodimer partner (SHP) expression in the liver cells. The main mechanism of metformin’s action is related to its activation of the AMPK enzyme and regulation of the energy balance. AMPK is a heterothermic serine/threonine kinase made of a catalytic alpha subunit and two subunits of beta and a gamma regulator. This enzyme can measure the intracellular ratio of AMP/ATP. If this ratio is high, the amino acid threonine 172 available in its alpha chain would be activated by the phosphorylated liver kinase B1 (LKB1), leading to AMPK activation. Several studies have indicated that apart from its significant role in the reduction of blood glucose level, metformin activates the AMPK enzyme that in turn has various efficient impacts on the regulation of various processes, including controlling inflammatory conditions, altering the differentiation pathway of immune and non-immune cell pathways, and the amelioration of various cancers, liver diseases, inflammatory bowel disease (IBD), kidney diseases, neurological disorders, etc. Metformin’s activation of AMPK enables it to control inflammatory conditions, improve oxidative status, regulate the differentiation pathways of various cells, change the pathological process in various diseases, and finally have positive therapeutic effects on them. Due to the activation of AMPK and its role in regulating several subcellular signalling pathways, metformin can be effective in altering the cells’ proliferation and differentiation pathways and eventually in the prevention and treatment of certain diseases.

Metformin: Sex/Gender Differences in Its Uses and Effects—Narrative Review

Metformin (MTF) occupies a major and fundamental position in the therapeutic management of type 2 diabetes mellitus (T2DM). Gender differences in some effects and actions of MTF have been reported. Women are usually prescribed lower MTF doses compared to men and report more gastrointestinal side effects. The incidence of cardiovascular events in women on MTF has been found to be lower to that of men on MTF. Despite some promising results with MTF regarding pregnancy rates in women with PCOS, the management of gestational diabetes, cancer prevention or adjunctive cancer treatment and COVID-19, most robust meta-analyses have yet to confirm such beneficial effects.

Curcumin regulates the homeostasis of Th17/Treg and improves the composition of gut microbiota in type 2 diabetic mice with colitis

Diabetes mellitus (DM) is one of the most common complications in patients with ulcerative colitis (UC). Curcumin has a wide range of bioactive and pharmacological properties and is commonly used as an adjunct to the treatment of UC and DM. However, the role of curcumin in UC complicated by DM has not been elucidated. Therefore, this study was conducted to construct a model of UC complicating diabetes by inducing UC in DB mice (spontaneously diabetic) with dextran sodium sulfate. In this study, curcumin (100 mg/kg/day) significantly improved the symptoms of diabetes complicated by UC, with a lower insulin level, heavier weight, longer and lighter colons, fewer mucosal ulcers and less inflammatory cell infiltration. Moreover, compared to untreated DB mice with colitis, curcumin‐treated mice showed weaker Th17 responses and stronger Treg responses. In addition, curcumin regulated the diversity and relative abundance of intestinal microbiota in mice with UC complicated by DM at the phylum, class, order, family and genus levels. Collectively, curcumin effectively alleviated colitis in mice with type 2 diabetes mellitus by restoring the homeostasis of Th17/Treg and improving the composition of the intestinal microbiota

Intertwined Relationship of Mitochondrial Metabolism, Gut Microbiome and Exercise Potential

The microbiome has emerged as a key player contributing significantly to the human physiology over the past decades. The potential microbial niche is largely unexplored in the context of exercise enhancing capacity and the related mitochondrial functions. Physical exercise can influence the gut microbiota composition and diversity, whereas a sedentary lifestyle in association with dysbiosis can lead to reduced well-being and diseases. Here, we have elucidated the importance of diverse microbiota, which is associated with an individual's fitness, and moreover, its connection with the organelle, the mitochondria, which is the hub of energy production, signaling, and cellular homeostasis. Microbial by-products, such as short-chain fatty acids, are produced during regular exercise that can enhance the mitochondrial capacity. Therefore, exercise can be employed as a therapeutic intervention to circumvent or subside various metabolic and mitochondria-related diseases. Alternatively, the microbiome-mitochondria axis can be targeted to enhance exercise performance. This review furthers our understanding about the influence of microbiome on the functional capacity of the mitochondria and exercise performance, and the interplay between them.

Metformin: Expanding the Scope of Application-Starting Earlier than Yesterday, Canceling Later

Today the area of application of metformin is expanding, and a wealth of data point to its benefits in people without carbohydrate metabolism disorders. Already in the population of people leading an unhealthy lifestyle, before the formation of obesity and prediabetes metformin smooths out the adverse effects of a high-fat diet. Being prescribed at this stage, metformin will probably be able to, if not prevent, then significantly reduce the progression of all subsequent metabolic changes. To a large extent, this review will discuss the proofs of the evidence for this. Another recent important change is a removal of a number of restrictions on its use in patients with heart failure, acute coronary syndrome and chronic kidney disease. We will discuss the reasons for these changes and present a new perspective on the role of increasing lactate in metformin therapy.