SGLT2 inhibition via dapagliflozin improves generalized vascular dysfunction and alters the gut microbiota in type 2 diabetic mice

Correlation and association analyses in microbiome study integrating multiomics in health and disease

Correlation and association analyses are one of the most widely used statistical methods in research fields, including microbiome and integrative multiomics studies. Correlation and association have two implications: dependence and co-occurrence. Microbiome data are structured as phylogenetic tree and have several unique characteristics, including high dimensionality, compositionality, sparsity with excess zeros, and heterogeneity. These unique characteristics cause several statistical issues when analyzing microbiome data and integrating multiomics data, such as large p and small n, dependency, overdispersion, and zero-inflation. In microbiome research, on the one hand, classic correlation and association methods are still applied in real studies and used for the development of new methods; on the other hand, new methods have been developed to target statistical issues arising from unique characteristics of microbiome data. Here, we first provide a comprehensive view of classic and newly developed univariate correlation and association-based methods. We discuss the appropriateness and limitations of using classic methods and demonstrate how the newly developed methods mitigate the issues of microbiome data. Second, we emphasize that concepts of correlation and association analyses have been shifted by introducing network analysis, microbe-metabolite interactions, functional analysis, etc. Third, we introduce multivariate correlation and association-based methods, which are organized by the categories of exploratory, interpretive, and discriminatory analyses and classification methods. Fourth, we focus on the hypothesis testing of univariate and multivariate regression-based association methods, including alpha and beta diversities-based, count-based, and relative abundance (or compositional)-based association analyses. We demonstrate the characteristics and limitations of each approaches. Fifth, we introduce two specific microbiome-based methods: phylogenetic tree-based association analysis and testing for survival outcomes. Sixth, we provide an overall view of longitudinal methods in analysis of microbiome and omics data, which cover standard, static, regression-based time series methods, principal trend analysis, and newly developed univariate overdispersed and zero-inflated as well as multivariate distance/kernel-based longitudinal models. Finally, we comment on current association analysis and future direction of association analysis in microbiome and multiomics studies.

The consequences of altered microbiota in immune-related chronic kidney disease

The normal gut microbiome modulates host enterocyte metabolism and shapes local and systemic immunity. Accumulation of urea and other waste products in chronic kidney disease induces gut dysbiosis and intestinal wall inflammation (leaky gut). There are decreased numbers of bacteria that generate short-chain fatty acids, which are an important nutrient source for host enterocytes and also contribute to regulation of the host immune system. Anaerobic proteolytic bacteria that express urease, uricase and indole and p-cresol enzymes, such as Enterobacteria and Enterococci, are increased. Microbial-derived uremic toxins such as indoxyl sulfate and trimethylamine N-oxide contribute to the pathophysiology of immune-related kidney diseases such as diabetic nephropathy, lupus nephritis and immunoglobulin A (IgA) nephropathy. Animal and clinical studies suggest potential benefits of dietary and probiotic interventions in slowing the progression of immune-related kidney diseases.

The gut microbiota and its interactions with cardiovascular disease

The intestine is colonized by a considerable community of microorganisms that cohabits within the host and plays a critical role in maintaining host homeostasis. Recently, accumulating evidence has revealed that the gut microbial ecology plays a pivotal role in the occurrence and development of cardiovascular disease (CVD). Moreover, the effects of imbalances in microbe-host interactions on homeostasis can lead to the progression of CVD. Alterations in the composition of gut flora and disruptions in gut microbial metabolism are implicated in the pathogenesis of CVD. Furthermore, the gut microbiota functions like an endocrine organ that produces bioactive metabolites, including trimethylamine/trimethylamine N-oxide, short-chain fatty acids and bile acids, which are also involved in host health and disease via numerous pathways. Thus, the gut microbiota and its metabolic pathways have attracted growing attention as a therapeutic target for CVD treatment. The fundamental purpose of this review was to summarize recent studies that have illustrated the complex interactions between the gut microbiota, their metabolites and the development of common CVD, as well as the effects of gut dysbiosis on CVD risk factors. Moreover, we systematically discuss the normal physiology of gut microbiota and potential therapeutic strategies targeting gut microbiota to prevent and treat CVD.

Control of 24-hour blood pressure with SGLT2 inhibitors to prevent cardiovascular disease

The presence of hypertension (HTN) in patients with diabetes mellitus (DM) further worsens cardiovascular disease (CVD) prognosis. In addition, masked HTN and abnormal circadian blood pressure (BP) variability are common among patients with DM. Clinical trial data show that sodium-glucose cotransporter 2 inhibitors (SGLT2i) improve CVD prognosis and prevent progression of renal dysfunction in high-risk patients with type 2 DM (T2DM). Consistent reductions in 24-hour, daytime and nocturnal BP have been documented during treatment with SGLT2i in patients with DM and HTN, and these reductions are of a magnitude that is likely to be clinically significant. SGLT2i agents also appear to have beneficial effects on morning, evening and nocturnal home BP. Greater reductions in BP during treatment with SGLT2i have been reported in patient subgroups with higher body mass index, and in those with higher baseline BP. Other documented beneficial effects of SGLT2i include reductions in arterial stiffness and the potential to decrease the apnea-hypopnea index in patients with DM and obstructive sleep apnea. Recent guidelines highlight the important role of SGLT2i as part of the pharmacological management of patients with DM and HTN, and recommend consideration of SGLT2i early in the clinical course to reduce all-cause and CVD mortality in patients with T2DM and CVD. Overall, available data support a role for SGLT2i as effective BP-lowering agents in patients with T2DM and poorly controlled HTN, irrespective of baseline glucose control status. Sustained improvements in 24-hour BP and the 24-hour BP profile are likely to contribute to the CVD benefits of SGLT2i treatment.

The role of diosgenin in diabetes and diabetic complications

Diabetes mellitus is a chronic and common metabolic disease that seriously endangers human health. Hyperglycemia and long-term metabolic disorders in diabetes will cause damage to the whole body tissues and organs, resulting in serious complications. Nowadays, drugs for treating diabetes on the market has strong side effects, new treatments thus are urgently needed. Natural therapy of natural ingredients is a promising avenue, this is because natural ingredients are safer and they also show strong activity in the treatment of diabetes. Diosgenin is such a very biologically active natural steroidal sapogenin. The research of diosgenin in the treatment of diabetes and its complications has been widely reported. This article reviews the effects of diosgenin through multiple targets and multiple pathways in diabetes and its complications which including diabetic nephropathy, diabetic liver disease, diabetic neuropathy, diabetic vascular disease, diabetic cardiomyopathy, diabetic reproductive dysfunction, and diabetic eye disease.

Update in recent clinical trials in heart failure

PURPOSE OF REVIEW

Heart failure represents a major growing health problem in developed world. This article aims to review recent heart failure trials that have significantly impacted the management of heart failure.

RECENT FINDINGS

Despite advances in heart failure, mortality and morbidity remains elevated amongst patients. Recent clinical trials demonstrate promising treatment strategies that likely impact clinical practice; including heart failure prevention with the use of SGLT2-inhibitors in patients with diabetes and cardiovascular risk, new treatments that may abrogate disease progression in cardiac amyloidosis, intravenous iron therapy in iron deficiency anemia in chronic systolic heart failure, predischarge treatment with angiotensin receptor blocker with neprilysin inhibition (ARNi) in patients hospitalized for acute decompensated heart failure, and newer continuous flow left ventricular assist device with increased durability and efficacy in patients with Stage D heart failure.

SUMMARY

Recent clinical trials with SGLT2 inhibitors, therapies targeting transthyretin cardiac amyloidosis, iron, angiotensin receptor blocker with neprilysin inhibition and newer mechanical circulatory support devices are very promising as practice changing new treatment strategies in prevention and treatment of heart failure. This article presents a summary of important trials and should be of practical value to both clinicians and researchers.

Gut Microbiota, Obesity and Bariatric Surgery: Current Knowledge and Future Perspectives

BACKGROUND

There is an urgent need for a better understanding and management of obesity and obesity- associated diseases. It is known that obesity is associated with structural and functional changes in the microbiome.

METHODS

The purpose of this review is to present current evidence from animal and human studies, demonstrating the effects and the potential efficacy of microbiota modulation in improving obesity and associated metabolic dysfunctions.

RESULTS

This review discusses possible mechanisms linking gut microbiota dysbiosis and obesity, since there is a dual interaction between the two of them. Furthermore, comments on bariatric surgery, as a favourable model to understand the underlying metabolic and inflammatory effects, as well as its association with changes in the composition of the gut microbiota, are included. Also, a possible impact of anti-obesity drugs and the novel antidiabetic drugs on the gut microbiota has been briefly discussed.

CONCLUSION

More research is needed to better understand here discussed the association between microbiota modulation and obesity. It is expected that research in this field, in the following years, will lead to a personalized therapeutic approach considering the patient's microbiome, and also give rise to the discovery of new drugs and/or the combination therapies for the management of obesity and obesity-related co-morbidities.

Reinterpreting Cardiorenal Protection of Renal Sodium-Glucose Cotransporter 2 Inhibitors via Cellular Life History Programming

Cardiovascular outcome trials have provided evidence that sodium-glucose cotransporter 2 inhibitor (SGLT2i) treatment is associated with remarkably favorable cardiovascular outcomes. Here, we offer a novel hypothesis that may encompass many of these hypothetical mechanisms, i.e., the ability of SGLT2i to modify the trajectory of cell response to a toxic environment through modifications of cellular life history programs, either the defense program or the dormancy program. The choice between these programs is mainly determined by the environment. Hyperglycemia can be considered a toxic determinant able to interfere with the basic programs of cell evolution. While the defense program is characterized by activation of the immune response and anabolic metabolism, the dormancy program is an energy-preserving state with high resistance to environmental stressors, and it has strong analogy with animal hibernation where fuel is stored, metabolic rate is suppressed, and insulin secretion is reduced. The metabolic changes that follow treatment with SGLT2i are reminiscent of the metabolic picture characteristic of the dormancy program. Therefore, we hypothesize that the beneficial cardioprotective effects of SGLT2i may be related to their ability to switch cell life programming from a defense to a dormancy state, thus lending additional benefit.

Doxorubicin Induces Endotheliotoxicity and Mitochondrial Dysfunction via ROS/eNOS/NO Pathway

Background: Doxorubicin (Dox) can induce endotheliotoxicity and damage the vascular endothelium (VE). The most principle mechanism might be excess reactive oxygen species (ROS) generation. Nevertheless, the characteristics of ROS generation, downstream mechanisms, and target organelles in Dox-induced endotheliotoxicity have yet to be elucidated.

Methods and Results: In order to explore the related problems, the VE injury models were established in mice and human umbilical vein endothelial cells (HUVECs) by Dox-induced endotheliotoxicity. Results showed that the activities of lactate dehydrogenase (LDH) and creatine kinase of mice’s serum increased after injected Dox. The thoracic aortic strips’ endothelium-dependent dilation was significantly impaired, seen noticeable inflammatory changes, and brown TUNEL-positive staining in microscopy. After Dox-treated, HUVECs viability lowered, LDH and caspase-3 activities, and apoptotic cells increased. Both intracellular/mitochondrial ROS generation significantly increased, and intracellular ROS generation lagged behind mitochondria. HUVECs treated with Dox plus ciclosporin A (CsA) could basically terminate ROS burst, but plus edaravone (Eda) could only delay or inhibit, but could not completely cancel ROS burst. Meanwhile, the expression of endothelial nitric oxide synthase (eNOS) decreased, especially phosphorylation of eNOS significantly. Then nitric oxide content decreased, the mitochondrial function was impaired, mitochondrial membrane potential (MMP) impeded, mitochondrial swelled, mitochondrial permeability transition pore (mPTP) was opened, and cytochrome C was released from mitochondria into the cytosol.

Conclusion: Dox produces excess ROS in the mitochondria, thereby weakens the MMP, opens mPTP, activates the ROS-induced ROS release mechanism, induces ROS burst, and leads to mitochondrial dysfunction, which in turn damages VE. Therefore, interrupting any step of the cycles, as mentioned above can end the related vicious cycle and prevent the occurrence and development of injury.

Dapagliflozin Modulates the Fecal Microbiota in a Type 2 Diabetic Rat Model

Background: The gut microbiota is recognized as a major modulator of metabolic disorders such as type 2 diabetes. Dapagliflozin, sodium glucose cotransporter 2 inhibitors (SGLT2i), enhances renal glucose excretion, and lowers blood glucose levels. The study aimed to determine the effects of dapagliflozin on fecal microbiota in a type 2 diabetic rat model. Methods: Four-week-old male Sprague Dawley rats (n = 24) were fed a high-fat diet (HFD) for 8 weeks and then given a single dose of STZ injection (30 mg/kg, i.p). They were randomly divided into three groups (n = 8). Each group received intragastric infusion of normal saline (2 ml, 0.9%) or metformin (215.15 mg/kg/day) or dapagliflozin (1 mg/kg/day) for 4 weeks. Blood glucose levels and plasma insulin levels were detected during intragastric glucose tolerance. Fecal samples were collected to access microbiome by 16S ribosomal RNA gene sequencing. Results: Dapagliflozin significantly decreased fasting and postprandial blood glucose levels as metformin in type 2 diabetic rats (P < 0.001). Enterotype was composed of Ruminococcaceae after treatment of dapagliflozin, whereas Ruminococcaceae and Muribaculaceae were the main enterotypes following metformin treatment. Dapagliflozin did not increase the abundance of beneficial bacteria including Lactobacillaceae and Bifidobacteriaceae. However, these were increased in the metformin group. It is surprising to find that Proteobacteria (especially Desulfovibrionaceae) were enriched in the dapagliflozin group. Conclusion: Dapagliflozin and metformin exerted complementary effects on the main beneficial bacteria. A combination of these two drugs might be beneficial to improve the structure of fecal microbiota in the treatment of type 2 diabetes.

Effects of Non-insulin Anti-hyperglycemic Agents on Gut Microbiota: A Systematic Review on Human and Animal Studies

Background: As growing evidence links gut microbiota with the therapeutic efficacy and side effects of anti-hyperglycemic drugs, this article aims to provide a systematic review of the reciprocal interactions between anti-hyperglycemic drugs and gut microbiota taxa, which underlie the effect of the gut microbiome on diabetic control via bug-host interactions. Method: We followed the PRISMA requirements to perform a systematic review on human vs. animal gut microbiota data in PubMed, SCOPUS, and EMBASE databases, and used Cochrane, ROBIN-I, and SYRCLE tools to assess potential bias risks. The outcomes of assessment were trends on gut microbiota taxa, diversity, and associations with metabolic control (e.g., glucose, lipid) following anti-hyperglycemic treatment. Results: Of 2,804 citations, 64 studies (17/humans; 47/mice) were included. In human studies, seven were randomized trials using metformin or acarbose in obese, pre-diabetes, and type 2 diabetes (T2D) patients. Treatment of pre-diabetes and newly diagnosed T2D patients with metformin or acarbose was associated with decreases in genus of Bacteroides, accompanied by increases in both Bifidobacterium and Lactobacillus. Additionally, T2D patients receiving metformin showed increases in various taxa of the order Enterobacteriales and the species Akkermansia muciniphila. Of seven studies with significant differences in beta-diversity, the incremental specific taxa were associated with the improvement of glucose and lipid profiles. In mice, the effects of metformin on A. muciniphila were similar, but an inverse association with Bacteroides was reported. Animal studies on other anti-hyperglycemic drugs, however, showed substantial variations in results. Conclusions: The changes in specific taxa and β-diversity of gut microbiota were associated with metformin and acarbose in humans while pertinent information for other anti-hyperglycemic drugs could only be obtained in rodent studies. Further human studies on anti-hyperglycemic drugs other than metformin and acarbose are needed to explore gut microbiota's role in their therapeutic efficacies and side effects.

Endothelium as a Therapeutic Target in Diabetes Mellitus: From Basic Mechanisms to Clinical Practice

Endothelium plays an essential role in human homeostasis by regulating arterial blood pressure, distributing nutrients and hormones as well as providing a smooth surface that modulates coagulation, fibrinolysis and inflammation. Endothelial dysfunction is present in Diabetes Mellitus (DM) and contributes to the development and progression of macrovascular disease, while it is also associated with most of the microvascular complications such as diabetic retinopathy, nephropathy and neuropathy. Hyperglycemia, insulin resistance, hyperinsulinemia and dyslipidemia are the main factors involved in the pathogenesis of endothelial dysfunction. Regarding antidiabetic medication, metformin, gliclazide, pioglitazone, exenatide and dapagliflozin exert a beneficial effect on Endothelial Function (EF); glimepiride and glibenclamide, dipeptidyl peptidase-4 inhibitors and liraglutide have a neutral effect, while studies examining the effect of insulin analogues, empagliflozin and canagliflozin on EF are limited. In terms of lipid-lowering medication, statins improve EF in subjects with DM, while data from short-term trials suggest that fenofibrate improves EF; ezetimibe also improves EF but further studies are required in people with DM. The effect of acetylsalicylic acid on EF is dose-dependent and lower doses improve EF while higher ones do not. Clopidogrel improves EF, but more studies in subjects with DM are required. Furthermore, angiotensin- converting-enzyme inhibitors /angiotensin II receptor blockers improve EF. Phosphodiesterase type 5 inhibitors improve EF locally in the corpus cavernosum. Finally, cilostazol exerts favorable effect on EF, nevertheless, more data in people with DM are required.

The Mechanism of Metabolic Influences on the Endogenous GLP-1 by Oral Antidiabetic Medications in Type 2 Diabetes Mellitus

Incretin-based therapy is now a prevalent treatment option for patients with type 2 diabetes mellitus (T2DM). It has been associated with considerably good results in the management of hyperglycemia with cardiac or nephron-benefits. For this reason, it is recommended for individuals with cardiovascular diseases in many clinical guidelines. As an incretin hormone, glucagon-like peptide-1 (GLP-1) possesses multiple metabolic benefits such as optimizing energy usage, maintaining body weight, β cell preservation, and suppressing neurodegeneration. However, recent studies indicate that oral antidiabetic medications interact with endogenous or exogenous GLP-1. Since these drugs are transported to distal intestine portions, there are concerns whether these oral drugs directly stimulate intestinal L cells which release GLP-1, or whether they do so via indirect inhibition of the activity of dipeptidyl peptidase-IV (DPP-IV). In this review, we discuss the metabolic relationships between oral antihyperglycemic drugs from the aspect of gut, microbiota, hormones, β cell function, central nervous system, and other cellular mechanisms.

Effects of 12-week treatment with dapagliflozin and gliclazide on faecal microbiome: Results of a double-blind randomized trial in patients with type 2 diabetes

AIMS/HYPOTHESIS

Patients with type 2 diabetes (T2D) are usually treated with (combinations of) glucose-lowering medication. The effects of these drugs can be influenced by intestinal microbiota and vice versa, as these drugs can also influence microbiome composition. However, as there is currently little clinical insight into this bug-drug interaction, our study aimed to evaluate the effects of 12-week treatment with the SGLT2 inhibitor dapagliflozin and sulphonylurea gliclazide on gut microbiome composition in T2D patients treated with metformin.

METHODS

A total of 44 patients were randomized to either dapagliflozin or gliclazide treatment for 12 weeks. At baseline and after 12 weeks, faecal samples and 24-h urine were collected. During study visits, anthropometric data were measured and blood samples drawn after an overnight fast. Microbiome composition was determined by 16S rRNA gene sequencing. Plasma glucose, insulin, HbA_1c and urinary glucose excretion were measured using conventional methods.

RESULTS

While dapagliflozin and gliclazide similarly improved glycaemic control, dapagliflozin reduced and gliclazide increased fasting insulin. Dapagliflozin also greatly increased urinary glucose excretion whereas gliclazide did not, while body mass index, fat mass percentage and waist circumference were reduced by dapagliflozin, but increased by gliclazide. However, neither treatment significantly affected either gut microbiome alpha diversity or composition and, after treatment, no associations were found between microbiome composition and other clinical parameters.

CONCLUSION

Even though gliclazide and dapagliflozin have different metabolic actions in patients with T2D, neither treatment altered the faecal microbiome, thereby suggesting that the observed metabolic changes are not mediated by their effects on the microbiota.

Tetramethylpyrazine Attenuates the Endotheliotoxicity and the Mitochondrial Dysfunction by Doxorubicin via 14-3-3γ/Bcl-2

Doxorubicin (Dox) with cardiotoxicity and endotheliotoxicity limits its clinical application for cancer. The toxicitic mechanism involves excess ROS generation. 14-3-3s have the protective effects on various injured tissues and cells. Tetramethylpyrazine (TMP) is an alkaloid extracted from the rhizome of Ligusticum wallichii and has multiple bioactivities. We hypothesize that TMP has the protective effects on vascular endothelium by upregulating 14-3-3γ. To test the hypothesis, Dox-induced endotheliotoxicity was used to establish vascular endothelium injury models in mice and human umbilical vein endothelial cells. The effects of TMP were assessed by determining thoracic aortic strips' endothelium-dependent dilation (EDD), as well as LDH, CK, caspase-3, SOD, CAT, GSH-Px activities and MDA level in serum, apoptotic rate, and histopathological changes of vascular tissue (in vivo). Also, cell viability, LDH and caspase-3 activities, ROS generation, levels of NAD⁺/NADH and GSH/GSSG, MMP, mPTP opening, and apoptotic rate were evaluated (in vitro). The expression of 14-3-3γ and Bcl-2, as well as phosphorylation of Bad (S112), were determined by Western blot. Our results showed that Dox-induced injury to vascular endothelium was decreased by TMP via upregulating 14-3-3γ expression in total protein and Bcl-2 expression in mitochondria, activating Bad (S112) phosphorylation, maintaining EDD, reducing LDH, CK, and caspase-3 activities, thereby causing a reduction in apoptotic rate, and histopathological changes of vascular endothelium (in vivo). Furthermore, TMP increased cell viability and MMP levels, maintained NAD⁺/NADH, GSH/GSSG balance, decreased LDH and caspase-3 activities, ROS generation, mPTP opening, and apoptotic rate (in vitro). However, the protective effects to vascular endothelium of TMP were significantly canceled by pAD/14-3-3γ-shRNA, an adenovirus that caused knockdown 14-3-3γ expression, or ABT-737, a specific Bcl-2 inhibitor. In conclusion, this study is the first to demonstrate that TMP protects the vascular endothelium against Dox-induced injury via upregulating 14-3-3γ expression, promoting translocation of Bcl-2 to the mitochondria, closing mPTP, maintaining MMP, inhibiting RIRR mechanism, suppressing oxidative stress, improving mitochondrial function, and alleviating Dox-induced endotheliotoxicity.

Iron Overload Damages the Endothelial Mitochondria via the ROS/ADMA/DDAHII/eNOS/NO Pathway

It has been recognized that iron overload may harm the body's health. Vascular endothelial cells (VECs) are one of the main targets of iron overload injury, and the mechanism involved was thought to be related to the excessive generation of reactive oxygen species (ROS). However, the subcellular and temporal characteristics of ROS generation, potential downstream mechanisms, and target organelles in VECs injured by iron overload have not been expounded yet. In this study, we elucidated the abovementioned issues through both in vivo and in vitro experiments. Mice were fed pellet diets that were supplemented with iron for 4 consecutive months. Results showed that the thoracic aortic strips' endothelium-dependent dilation was significantly impaired and associated with inflammatory changes, noticeable under brown TUNEL-positive staining in microscopy analysis. In addition, the serum content of asymmetric dimethylarginine (ADMA) increased, whereas nitric oxide (NO) levels decreased. Furthermore, the dimethylarginine dimethylaminohydrolase II (DDAHII) expression and activity, as well as the phosphorylation of endothelial nitric oxide synthase (eNOS) in aortic tissue, were inhibited. Human umbilical vein endothelial cells were treated with 50 μM iron dextran for 48 hours, after which the cell viability, NO content, DDAHII expression and activity, and phosphorylation of eNOS decreased and lactate dehydrogenase and caspase-3 activity, ADMA content, and apoptotic cells significantly increased. After the addition of L-arginine (L-Arg) or pAD/DDAHII, the abovementioned changes were reversed. By dynamically detecting the changes of ROS generation in the cytoplasm and mitochondria and interfering with different aspects of signaling pathways, we have confirmed for the first time that excessive ROS originates from the cytoplasm and activates the ROS-induced ROS release (RIRR) mechanism, leading to mitochondrial dysfunction. Together, our data suggested that excessive free iron ions produced excess ROS in the cytoplasm. Thus, excess ROS create one vicious circle by activating the ADMA/eNOS/DDAHII/NO pathway and another vicious circle by activation of the RIRR mechanism, which, when combined, induce a ROS burst, resulting in mitochondrial dysfunction and damaged VECs.

Dapagliflozin improves left ventricular remodeling and aorta sympathetic tone in a pig model of heart failure with preserved ejection fraction

Background

Heart failure with preserved ejection fraction (HFpEF) is a difficult disease with high morbidity and mortality rates and lacks an effective treatment. Here, we report the therapeutic effect of dapagliflozin, a sodium-glucose cotransporter 2 inhibitor (SGLT2i), on hypertension + hyperlipidemia-induced HFpEF in a pig model.

Methods

HFpEF pigs were established by infusing a combination of deoxycorticosterone acetate (DOCA) and angiotensin II (Ang II), and Western diet (WD) feeding for 18 weeks. In the 9th week, half of the HFpEF pigs were randomly assigned to receive additional dapagliflozin treatment (10 mg/day) by oral gavage daily for the next 9 weeks. Blood pressure, lipid levels, echocardiography and cardiac hemodynamics for cardiac structural and functional changes, as well as epinephrine and norepinephrine concentrations in the plasma and tissues were measured. After sacrifice, cardiac fibrosis, the distribution of tyrosine hydroxylase (TH), inflammatory factors (IL-6 and TNF-α) and NO-cGMP-PKG pathway activity in the cardiovascular system were also determined.

Results

Blood pressure, total cholesterol (TC), triglyceride (TG) and low-density lipoprotein (LDL) were markedly increased in HFpEF pigs, but only blood pressure was significantly decreased after 9 weeks of dapagliflozin treatment. By echocardiographic and hemodynamic assessment, dapagliflozin significantly attenuated heart concentric remodeling in HFpEF pigs, but failed to improve diastolic function and compliance with the left ventricle (LV). In the dapagliflozin treatment group, TH expression and norepinephrine concentration in the aorta were strongly mitigated compared to that in the HFpEF group. Moreover, inflammatory cytokines such as IL-6 and TNF-α in aortic tissue were markedly elevated in HFpEF pigs and inhibited by dapagliflozin. Furthermore, the reduced expression of eNOS and the PKG-1 protein and the cGMP content in the aortas of HFpEF pigs were significantly restored after 9 weeks of dapagliflozin treatment.

Conclusion

9 weeks of dapagliflozin treatment decreases hypertension and reverses LV concentric remodeling in HFpEF pigs partly by restraining sympathetic tone in the aorta, leading to inhibition of the inflammatory response and NO-cGMP-PKG pathway activation.

The Chinese Herbal Formula Shenzhu Tiaopi Granule Results in Metabolic Improvement in Type 2 Diabetic Rats by Modulating the Gut Microbiota

Objective

The aim of this study is to investigate the implication of the Chinese herbal formula (CHF) Shenzhu tiaopi Granule (STG) in type 2 diabetes mellitus (T2DM) and discuss the mechanisms by which STG regulates the gut microbiota.

Method

Goto-Kakizaki (GK) rats and age-matched Wistar (W) rats were acclimatized for 1 week. The GK rats were randomly divided into 3 groups and orally gavaged with saline (model group, M), acarbose (acarbose group, A), and STG (granule of CHF group, G; the component of this formula includes Codonopsis pilosula, Rhizoma Atractylodis, Pinellia, Poria cocos, Pericarpium Citri Reticulatae, Coptis chinensis Franch, and Pueraria). The W rats were orally gavaged with saline (control group, C). The observation time was 8 weeks. The weight, fasting blood glucose (FBG) level, and blood lipid levels were tested. The 16S rRNA genes in the V3-V4 region were sequenced, and the structure of the gut microbiota was analysed.

Results

Compared to C, M displayed significant differences in blood glucose, gut microbiota, etc. (P<0.05; P<0.01). Compared to M, A and G showed a similar reduction in the FBG gain and a shift in the structure of the gut microbiota (P<0.05; P<0.01). Compared with A, G exhibited a significant decrease in weight, FBG level, and total cholesterol (P<0.05). The gut microbiota, Bacteroidetes, the Firmicutes/Bacteroidetes ratio, Allobaculum, and Desulfovibrionaceae were significantly decreased in response to the STG treatment, while Lactobacillus was significantly enriched (P<0.05; P<0.01). The community composition also differed at the phylum and genus levels based on the linear discriminant analysis effect size and heat map.

Conclusion

Our findings suggest that the composition of the gut microbiota was significantly changed in the diabetic GK rats compared with that in the normal W rats. STG treatment can improve glucose and lipid levels and modulate the gut microbiota in T2DM rats.

Influence of Sodium Glucose Cotransporter 2 Inhibition on Physiological Adaptation to Endurance Exercise Training

CONTEXT

The combination of two beneficial antidiabetes interventions, regular exercise and pharmaceuticals, is intuitively appealing. However, metformin, the most commonly prescribed diabetes medication, attenuates the favorable physiological adaptations to exercise; in turn, exercise may impede the action of metformin.

OBJECTIVE

We sought to determine the influence of an alternative diabetes treatment, sodium glucose cotransporter 2 (SGLT2) inhibition, on the response to endurance exercise training.

DESIGN, PARTICIPANTS, AND INTERVENTION

In a randomized, double-blind, repeated measures parallel design, 30 sedentary overweight and obese men and women were assigned to 12 weeks of supervised endurance exercise training, with daily ingestion of either a placebo or SGLT2 inhibitor (dapagliflozin: ≤10 mg/day).

OUTCOME MEASUREMENTS AND RESULTS

Endurance exercise training favorably modified body mass, body composition (dual-energy x-ray absorptiometry), peak oxygen uptake (graded exercise with indirect calorimetry), responses to standardized submaximal exercise (indirect calorimetry, heart rate, and blood lactate), and skeletal muscle (vastus lateralis) citrate synthase activity (main effects of exercise training, all P < 0.05); SGLT2 inhibition did not influence any of these physiological adaptations (exercise training × treatment interaction, all P > 0.05). However, after endurance exercise training, fasting blood glucose was greater with SGLT2 inhibition, and increased insulin sensitivity (oral glucose tolerance test/Matsuda index) was abrogated with SGLT2 inhibition (exercise training × treatment interaction, P < 0.01).

CONCLUSION

The efficacy of combining two beneficial antidiabetes interventions, regular endurance exercise and SGLT2 inhibition, was not supported. SGLT2 inhibition blunted endurance exercise training-induced improvements in insulin sensitivity, independent of effects on aerobic fitness or body composition.

Effect of ipragliflozin, an SGLT2 inhibitor, on cardiac histopathological changes in a non-diabetic rat model of cardiomyopathy

AIMS

We investigated the effect of the selective sodium-dependent glucose cotransporter 2 (SGLT2) inhibitor ipragliflozin on cardiac dysfunction and histopathology in a non-diabetic rat model of cardiomyopathy.

MAIN METHODS

Ipragliflozin was mixed with chow (0.01%, w/w) and administered to male DahlS.Z-Lepr^fa/Lepr^fa (DS/obese) rats for 8 weeks. Male DahlS.Z-Lepr⁺/Lepr⁺ (DS/lean) rats of the same age were used as controls. Systolic blood pressure (SBP) and heart rate (HR) were measured every 4 weeks. After 8 weeks of treatment, echocardiography and histopathological examinations were performed. Further, the effect of ipragliflozin on blood and urine parameters were investigated.

KEY FINDINGS

In the DS/obese rats, ipragliflozin delayed the age-related increase in SBP without affecting HR, reduced left ventricular (LV) mass and intraventricular septal thickness in echocardiography, and ameliorated hypertrophy of cardiomyocytes and LV fibrosis in histopathological examination. Although ipragliflozin significantly increased both urine volume and urinary glucose excretion in DS/obese rats, it did not alter plasma glucose levels.

SIGNIFICANCE

Ipragliflozin prevented LV hypertrophy and fibrosis in non-diabetic DS/obese rats without affecting plasma glucose levels. These findings suggest that SGLT2 inhibitors have a cardio-protective effect in non-diabetic patients with cardiomyopathy.

How does empagliflozin improve arterial stiffness in patients with type 2 diabetes mellitus? Sub analysis of a clinical trial

Background

Empagliflozin has been shown to reduce cardiovascular mortality, but the underlying pathogenetic mechanisms are poorly understood. It was previously demonstrated that empagliflozin improved arterial stiffness.

Methods

Our analysis comprising 58 patients with type 2 diabetes mellitus identifies factors triggering the improvement of arterial stiffness. All patients participated in an investigator-initiated, prospective, double-blind, randomized, placebo-controlled, interventional clinical trial (http://www.ClinicalTrials.gov: NCT02471963, registered 15th June 2015, retrospectively registered) and received either 6-weeks treatment with 25 mg empagliflozin orally once daily or placebo (crossover). Central systolic pressure and central pulse pressure were recorded by the SphygmoCor System (AtCor Medical). Now, we investigated the impact of parameters of glucose metabolism, volume status, sympathetic activation, lipids, uric acid, blood pressure and inflammation on vascular parameters of arterial stiffness using multivariate regression analysis.

Results

As previously reported, therapy with empagliflozin improved arterial stiffness as indicated by reduced central systolic blood pressure (113.6 ± 12.1 vs 118.6 ± 12.9 mmHg, p < 0.001), central pulse pressure (39.1 ± 10.2 vs 41.9 ± 10.7 mmHg, p = 0.027) forward (27.1 ± 5.69 vs 28.7 ± 6.23 mmHg, p = 0.031) as well as reflected wave amplitude (18.9 ± 5.98 vs 20.3 ± 5.97 mmHg, p = 0.045) compared to placebo. The multivariate regression analysis included age, sex and change between empagliflozin and placebo therapy of the following parameters: HbA1c, copeptin, hematocrit, heart rate, LDL-cholesterol, uric acid, systolic 24-h ambulatory blood pressure and high sensitive CRP (hsCRP). Besides the influence of age (beta = − 0.259, p = 0.054), sex (beta = 0.292, p = 0.040) and change in systolic 24-h ambulatory blood pressure (beta = 0.364, p = 0.019), the change of hsCRP (beta = 0.305, p = 0.033) emerged as a significant determinant of the empagliflozin induced reduction in arterial stiffness (placebo corrected). When replacing HbA1c with fasting plasma glucose in the multivariate regression analysis, a similar effect of the change in hsCRP (beta = 0.347, p = 0.017) on arterial stiffness parameters was found.

Conclusion

Besides age and sex, change in systolic 24-h ambulatory blood pressure and change in hsCRP were determinants of the empagliflozin induced improvement of vascular parameters of arterial stiffness, whereas parameters of change in glucose metabolism and volume status had no significant influence. Our analysis suggests that empagliflozin exerts, at least to some extent, its beneficial vascular effects via anti-inflammatory mechanisms.

Trial registrationhttp://www.ClinicalTrials.gov: NCT02471963, registered 15th June 2015, retrospectively registered

Crosstalk between gut microbiota and antidiabetic drug action

Type 2 diabetes (T2D) is a disorder characterized by chronic inflated blood glucose levels (hyperglycemia), at first due to insulin resistance and unregulated insulin secretion but with tendency towards global spreading. The gut microbiota is recognized to have an influence on T2D, although surveys have not formed a clear overview to date. Because of the interactions between gut microbiota and host homeostasis, intestinal bacteria are believed to play a large role in various diseases, including metabolic syndrome, obesity and associated disease. In this review, we highlight the animal and human studies which have elucidated the roles of metformin, α-glucosidase inhibitors, glucagon-like peptide-1 agonists, peroxisome proliferator-activated receptors γ agonists, inhibitors of dipeptidyl peptidase-4, sodium/glucose cotransporter inhibitors, and other less studied medications on gut microbiota. This review is dedicated to one of the most widespread diseases, T2D, and the currently used antidiabetic drugs and most promising new findings. In general, the gut microbiota has been shown to have an influence on host metabolism, food consumption, satiety, glucose homoeostasis, and weight gain. Altered intestinal microbiota composition has been noticed in cardiovascular diseases, colon cancer, rheumatoid arthritis, T2D, and obesity. Therefore, the main effect of antidiabetic drugs is on the microbiome composition, basically increasing the short-chain fatty acids-producing bacteria, responsible for losing weight and suppressing inflammation.

SGLT2 inhibition with empagliflozin improves coronary microvascular function and cardiac contractility in prediabetic ob/ob-/- mice

BACKGROUND

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) is the first class of anti-diabetes treatment that reduces mortality and risk for hospitalization due to heart failure. In clinical studies it has been shown that SGLT2i's promote a general shift to fasting state metabolism characterized by reduced body weight and blood glucose, increase in glucagon/insulin ratio and modest increase in blood ketone levels. Therefore, we investigated the connection between metabolic changes and cardiovascular function in the ob/ob-/- mice; a rodent model of early diabetes with specific focus on coronary microvascular function. Due to leptin deficiency these mice develop metabolic syndrome/diabetes and hepatic steatosis. They also develop cardiac contractile and microvascular dysfunction and are thus a promising model for translational studies of cardiometabolic diseases. We investigated whether this mouse model responded in a human-like manner to empagliflozin treatment in terms of metabolic parameters and tested the hypothesis that it could exert direct effects on coronary microvascular function and contractile performance.

METHODS

Lean, ob/ob-/- untreated and ob/ob-/- treated with SGLT2i were followed for 10 weeks. Coronary flow velocity reserve (CFVR) and fractional area change (FAC) were monitored with non-invasive Doppler ultrasound imaging. Food intake, urinary glucose excursion and glucose control via HbA1c measurements were followed throughout the study. Liver steatosis was assessed by histology and metabolic parameters determined at the end of the study.

RESULTS

Sodium-glucose cotransporter 2 inhibitors treatment of ob/ob-/- animals resulted in a switch to a more catabolic state as observed in clinical studies: blood cholesterol and HbA1c were decreased whereas glucagon/insulin ratio and ketone levels were increased. SGLT2i treatment reduced liver triglyceride, steatosis and alanine aminotransferase, an indicator for liver dysfunction. L-Arginine/ADMA ratio, a marker for endothelial function was increased. SGLT2i treatment improved both cardiac contractile function and coronary microvascular function as indicated by improvement of FAC and CFVR, respectively.

CONCLUSIONS

Sodium-glucose cotransporter 2 inhibitors treatment of ob/ob-/- mice mimics major clinical findings regarding metabolism and cardiovascular improvements and is thus a useful translational model. We demonstrate that SGLT2 inhibition improves coronary microvascular function and contractile performance, two measures with strong predictive values in humans for CV outcome, alongside with the known metabolic changes in a preclinical model for prediabetes and heart failure.

SGLT2 inhibition with empagliflozin attenuates myocardial oxidative stress and fibrosis in diabetic mice heart

Background

Hyperglycaemia associated with myocardial oxidative stress and fibrosis is the main cause of diabetic cardiomyopathy. Empagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor has recently been reported to improve glycaemic control in patients with type 2 diabetes in an insulin-independent manner. The aim of this study was to investigate the effect of empagliflozin on myocardium injury and the potential mechanism in type 2 diabetic KK-Ay mice.

Methods

Thirty diabetic KK-Ay mice were administered empagliflozin (10 mg/kg/day) by oral gavage daily for 8 weeks. After 8 weeks, heart structure and function were evaluated by echocardiography. Oxidants and antioxidants were measured and cardiac fibrosis was analysed using immunohistochemistry, Masson’s trichrome stain and Western blot.

Results

Results showed that empagliflozin improved diabetic myocardial structure and function, decreased myocardial oxidative stress and ameliorated myocardial fibrosis. Further study indicated that empagliflozin suppressed oxidative stress and fibrosis through inhibition of the transforming growth factor β/Smad pathway and activation of Nrf2/ARE signaling.

Conclusions

Glycaemic control with empagliflozin significantly ameliorated myocardial oxidative stress injury and cardiac fibrosis in diabetic mice. Taken together, these results indicate that the empagliflozin is a promising agent for the prevention and treatment of diabetic cardiomyopathy.

Bi-directional drug-microbiome interactions of anti-diabetics

Type 2 diabetes (T2D) has become a global epidemic. Although several drugs are available to manage T2D, problems associated with person-to-person variability in drug efficacy and potential side-effects remain unresolved. Owing to the emerging role of the gut microbiome in obesity and T2D, the interaction between gut microbes and anti-diabetic drugs and its influence on drugs' functions remains of immediate research interest. On one hand, drugs can manipulate gut microbiome composition and metabolic capacity. Conversely, the metabolic activities of the microbiome and its metabolites can also influence drug metabolism and effects. Hence, understanding this bi-directional drug-microbiome interaction and how it influences the clinical outcomes of antidiabetic drugs can pave the way to develop next-generation strategies to ameliorate diabetes. This review presents evidences demonstrating the putative interactions between anti-diabetic drugs and the gut microbiome, and discusses the potential of microbiome modulators to manipulate drug-microbiome interactions and the drug metabolism.

Effects of metformin, acarbose, and sitagliptin monotherapy on gut microbiota in Zucker diabetic fatty rats

OBJECTIVE

Recent studies have demonstrated that gut microbiota was closely related to metabolic disorders such as type 2 diabetes. Oral antidiabetic medications including metformin, acarbose and sitagliptin lowered blood glucose levels via acting on the gastrointestinal tract. The aim of the study was to observe the comparisons among those medications on gut microbiota composition.

RESEARCH DESIGN AND METHODS

Zucker diabetic fatty rats (n=32) were randomly divided into four groups, and had respectively gastric administration of normal saline (control), metformin (215.15 mg/kg/day), acarbose (32.27 mg/kg/day), or sitagliptin (10.76 mg/kg/day) for 4 weeks. Blood glucose levels were measured during an intragastric starch tolerance test after the treatments. 16S rRNA gene sequencing was used to access the microbiota in the fecal samples.

RESULTS

Metformin, acarbose, and sitagliptin monotherapy effectively decreased fasting and postprandial blood glucose levels (p<0.001). Acarbose group displayed specific cluster and enterotype mainly composed by Ruminococcus 2 while Lactobacillus was the dominant bacterium in the enterotype of the other three groups. The relative abundance of genera Ruminococcus 2 and Bifidobacterium was dramatically higher in acarbose group. Metformin and sitagliptin increased the relative abundance of genus Lactobacillus. Metagenomic prediction showed that the functional profiles of carbohydrate metabolism were enriched in acarbose group.

CONCLUSIONS

Metformin, acarbose and sitagliptin exerted different effects on the composition of gut microbiota and selectively increased the beneficial bacteria. Supplementation with specific probiotics may further improve the hypoglycemic effects of the antidiabetic drugs.

SGLT-2 inhibitors as promising therapeutics for non-alcoholic fatty liver disease: pathophysiology, clinical outcomes, and future directions

Nonalcoholic fatty liver disease (NAFLD) is increasingly recognized as a major expanding national and international health problem. Despite numerous investigations using a variety of therapeutic agents, the positive result on any single medication has not been established enough to gain widespread approval. This is in part related to concerns regarding side effects of agents, but is also related to the complex etiology of NAFLD. An often discussed question has been whether insulin resistance that is frequently present in those with NAFLD is a cause of NAFLD or is merely associated with the condition. Nevertheless, it is clear that a very high proportion of patients with NAFLD are obese, have elements of metabolic syndrome, or have type 2 diabetes (T2DM). Also, much progress has been made toward a better understanding of the pathophysiology of NAFLD. Life-style interventions resulting in weight loss remain the foundation for the prevention and treatment of NAFLD. In addition, agents such as Vitamin E and pioglitazone as well as other glycemia-lowering agents including Glucagon Like Peptide-1 (GLP-1) receptor agonists and Sodium Glucose Contransporter-2 inhibitors (SGLT-2i(s)) exhibit positive effects on the clinical course of NAFLD. This narrative review summarizes the current understanding of the diagnosis, epidemiology, and pathophysiology of NAFLD and specifically focuses on the efficacy of SGLT2i(s) as a potentially promising group of agents for the management of patients with NAFLD.

A sodium-glucose cotransporter 2 (SGLT2) inhibitor dapagliflozin comparison with insulin shows important effects on Zn2+-transporters in cardiomyocytes from insulin-resistant metabolic syndrome rats through inhibition of oxidative stress 1

Sodium-glucose cotransporter 2 (SGLT2) inhibitors showed significant effects in patients with diabetes or metabolic syndrome (MetS) with high cardiovascular risk. Although the increased intracellular Zn²⁺ level ([Zn²⁺]_i), oxidative stress, and altered cardiac matrix metalloproteinases (MMPs) in diabetic cardiomyopathy can intersect with different signaling pathways, the exact mechanisms are not known yet. Since either MMPs or SGLT2 have important roles in cardiac-fibrosis under hyperglycemia, we aimed to examine the role of SGLT2 inhibitor dapagliflozin (DAP) on cardiac Zn²⁺-transporters responsible for [Zn²⁺]_i-regulation, comparison to insulin (INS), together with MMP levels and systemic oxidative stress status in MetS-rats. High-carbohydrated diet-induced MetS-rats received DAP or INS for 2 weeks. DAP but not INS in MetS-rats significantly decreased high blood-glucose levels, while both treatments exerted benefits on increased total oxidative status and decreased total antioxidant status in MetS-rat plasma as well as in heart tissue. Protein levels of Zn²⁺-transporters, responsible for Zn²⁺-influx into cytosol, ZIP7 and ZIP14 were increased with significant decrease in ZIP8 of MetS-rat cardiomyoctes, while Zn²⁺-transporters, responsible for cytosolic Zn²⁺-efflux, ZnT7 was decreased with no change in ZnT8. Both treatments induced significant beneficial effects on altered ZIP14, ZIP8, and ZnT7 levels. Furthermore, both treatments exerted benefits on depressed gelatin-zymography and protein expression levels of MMP-2 and MMP-9 in MetS-rat ventricular cardiomyocytes. The direct effect of DAP on heart was also confirmed with measurements of left ventricular developed pressure. Overall, we showed that DAP has important antioxidant-like cardio-protective effects in MetS-rats, similar to INS-effect, affecting Zn²⁺-regulation via Zn²⁺-transporters, MMPs, and oxidative stress. Therefore one can suggest that SGLT2 inhibitors can be new therapeutic agents for cardio-protection not only in hyperglycemia but also in failing heart.

Effects of SGLT2 inhibitors on systemic and tissue low-grade inflammation: The potential contribution to diabetes complications and cardiovascular disease

Chronic low-grade inflammation is a recognized key feature associated with type 2 diabetes mellitus (T2DM) and its complications. In prospective randomized trials, sodium-glucose cotransporter type 2 (SGLT2) inhibitors have demonstrated benefits related to several cardiovascular and renal risk factors, including HbA_1c, blood pressure, body weight, renal hyperfiltration, and improvement of cardiorenal outcomes. SGLT2 inhibitors may improve adipose tissue function and induce decreases in serum leptin, TNF-α and IL-6 while increasing adiponectin. While data on high-sensitivity C-reactive protein and other inflammatory markers are relatively scarce in humans, in animals, a number of reports have shown reductions in cytokine and chemokine concentrations in parallel with protective effects against progression of atherosclerotic lesions. Experimental findings also suggest that part of the renoprotective effects of SGLT2 inhibition may be related to anti-inflammatory actions at the kidney level. Underlying mechanisms to explain this anti-inflammatory effect are multiple, but may involve weight loss, and reduction in adipose tissue inflammation, slight increase in ketone bodies and diminution of uric acid levels or attenuation of oxidative stress. However, further studies in diabetes patients with specific assessment of inflammatory markers are still necessary to determine the specific contribution of the anti-inflammatory action of SGLT2 inhibitors to the reduction of cardiovascular and renal complications and mortality observed with this class of antidiabetic drugs.