Effect of canagliflozin on renal threshold for glucose, glycemia, and body weight in normal and diabetic animal models

The relationship between SGLT2 and systemic blood pressure regulation

The sodium-glucose cotransporter 2 (SGLT2) is a glucose transporter that is located within the proximal tubule of the kidney's nephrons. While it is typically associated with the kidney, it was later identified in various areas of the central nervous system, including areas modulating cardiorespiratory regulation like blood pressure. In the kidney, SGLT2 functions by reabsorbing glucose from the nephron's tubule into the bloodstream. SGLT2 inhibitors are medications that hinder the function of SGLT2, thus preventing the absorption of glucose and allowing for its excretion through the urine. While SGLT2 inhibitors are not the first-line choice, they are given in conjunction with other pharmaceutical interventions to manage hyperglycemia in individuals with diabetes mellitus. SGLT2 inhibitors also have a surprising secondary effect of decreasing blood pressure independent of blood glucose levels. The implication of SGLT2 inhibitors in lowering blood pressure and its presence in the central nervous system brings to question the role of SGLT2 in the brain. Here, we evaluate and review the function of SGLT2, SGLT2 inhibitors, their role in blood pressure control, the future of SGLT2 inhibitors as antihypertensive agents, and the possible mechanisms of SGLT2 blood pressure control in the central nervous system.

Sympathetic Activation Promotes Sodium Glucose Co-Transporter-1 Protein Expression in Rodent Skeletal Muscle

The hyperactivation of the sympathetic nervous system (SNS) is linked to obesity, hypertension, and type 2 diabetes, which are characterized by elevated norepinephrine (NE) levels. Previous research has shown increased sodium-dependent glucose cotransporter 1 (SGLT1) protein levels in kidneys of hypertensive rodents, prompting investigation into the expression of SGLT1 in various tissues, such as skeletal muscle. This study aimed to assess (i) whether skeletal muscle cells and tissue express SGLT1 and SGLT2 proteins; (ii) if NE increases SGLT1 levels in skeletal muscle cells, and (iii) whether the skeletal muscle of neurogenically hypertensive mice exhibits increased SGLT1 expression. We found that (i) skeletal muscle cells and tissue are a novel source of the SGLT2 protein and that (ii) NE significantly elevated SGLT1 levels in skeletal muscle cells. As SGLT2 inhibition (SGLT2i) with Empagliflozin increased SGLT1 levels, in vivo studies with the dual inhibitor SGLT1/2i, Sotagliflozin were warranted. The treatment of neurogenically hypertensive mice using Sotagliflozin significantly reduced blood pressure. Our findings suggest that SNS activity upregulates the therapeutic target, SGLT1, in skeletal muscle, potentially worsening cardiometabolic control. As clinical trial data suggest cardiorenal benefits from SGLT2i, future studies should aim to utilize SGLT1i by itself, which may offer a therapeutic strategy for conditions with heightened SNS activity, such as hypertension, diabetes, and obesity.

mTORC1 and SGLT2 Inhibitors-A Therapeutic Perspective for Diabetic Cardiomyopathy

Diabetic cardiomyopathy is a critical diabetes-mediated co-morbidity characterized by cardiac dysfunction and heart failure, without predisposing hypertensive or atherosclerotic conditions. Metabolic insulin resistance, promoting hyperglycemia and hyperlipidemia, is the primary cause of diabetes-related disorders, but ambiguous tissue-specific insulin sensitivity has shed light on the importance of identifying a unified target paradigm for both the glycemic and non-glycemic context of type 2 diabetes (T2D). Several studies have indicated hyperactivation of the mammalian target of rapamycin (mTOR), specifically complex 1 (mTORC1), as a critical mediator of T2D pathophysiology by promoting insulin resistance, hyperlipidemia, inflammation, vasoconstriction, and stress. Moreover, mTORC1 inhibitors like rapamycin and their analogs have shown significant benefits in diabetes and related cardiac dysfunction. Recently, FDA-approved anti-hyperglycemic sodium-glucose co-transporter 2 inhibitors (SGLT2is) have gained therapeutic popularity for T2D and diabetic cardiomyopathy, even acknowledging the absence of SGLT2 channels in the heart. Recent studies have proposed SGLT2-independent drug mechanisms to ascertain their cardioprotective benefits by regulating sodium homeostasis and mimicking energy deprivation. In this review, we systematically discuss the role of mTORC1 as a unified, eminent target to treat T2D-mediated cardiac dysfunction and scrutinize whether SGLT2is can target mTORC1 signaling to benefit patients with diabetic cardiomyopathy. Further studies are warranted to establish the underlying cardioprotective mechanisms of SGLT2is under diabetic conditions, with selective inhibition of cardiac mTORC1 but the concomitant activation of mTORC2 (mTOR complex 2) signaling.

Association between Obstructive Sleep Apnea and Heart Failure in Adults-A Systematic Review

BACKGROUND

Heart failure (HF) patients commonly experience obstructive sleep apnea (OSA), which may worsen their condition. We reviewed a diverse range of studies to investigate the prevalence of OSA in HF patients, the effects of positive airway pressure (PAP) treatment, and the potential impact of sodium-glucose cotransporter-2 inhibitors (SGLT2i) and sacubitril/valsartan on OSA outcomes.

METHODS

We analyzed case-control, observational studies, and randomized controlled trials. Prevalence rates, PAP treatment, and HF pharmacotherapy were assessed.

RESULTS

Numerous studies revealed a high prevalence of OSA in HF patients, particularly with preserved ejection fraction. PAP treatment consistently improved an apnea-hypopnea index, left ventricular ejection fraction, oxygen saturation, and overall quality of life. Emerging evidence suggests that SGLT2i and sacubitril/valsartan might influence OSA outcomes through weight loss, improved metabolic profiles, and potential direct effects on upper airway muscles.

CONCLUSIONS

The complex interplay between OSA and HF necessitates a multifaceted approach. PAP treatment has shown promising results in improving OSA symptoms and HF parameters. Additionally, recent investigations into the effects of HF pharmacotherapy on OSA suggest their potential as adjunctive therapy. This review provides insights for clinicians and researchers, highlighting the importance of addressing OSA and HF in patient management strategies.

Role and mechanisms of SGLT-2 inhibitors in the treatment of diabetic kidney disease

Diabetic kidney disease (DKD) is a chronic inflammatory condition that affects approximately 20-40% of individuals with diabetes. Sodium-glucose co-transporter 2 (SGLT-2) inhibitors, emerging as novel hypoglycemic agents, have demonstrated significant cardiorenal protective effects in patients with DKD. Initially, it was believed that the efficacy of SGLT-2 inhibitors declined as the estimated glomerular filtration rate (eGFR) decreased, which led to their preferential use in DKD patients at G1-G3 stages. However, recent findings from the DAPA-CKD and EMPA-KIDNEY studies have revealed equally beneficial cardiorenal effects of SGLT-2 inhibitors in individuals at stage G4 DKD, although the underlying mechanism behind this phenomenon remains unclear. In this comprehensive analysis, we provide a systematic review of the mechanisms and functioning of SGLT-2 inhibitors, potential renal protection mechanisms, and the therapeutic efficacy and safety of SGLT-2 inhibitors in kidney diseases, with a particular focus on stage G4 DKD. Gaining a deeper understanding of the renal protective effect of SGLT-2 inhibitors and their underlying mechanisms is highly significance for the successful utilization of these inhibitors in the treatment of diverse kidney disorders.

Canagliflozin, an Inhibitor of the Na+-Coupled D-Glucose Cotransporter, SGLT2, Inhibits Astrocyte Swelling and Brain Swelling in Cerebral Ischemia

Brain swelling is a major cause of death and disability in ischemic stroke. Drugs of the gliflozin class, which target the Na+-coupled D-glucose cotransporter, SGLT2, are approved for type 2 diabetes mellitus (T2DM) and may be beneficial in other conditions, but data in cerebral ischemia are limited. We studied murine models of cerebral ischemia with middle cerebral artery occlusion/reperfusion (MCAo/R). Slc5a2/SGLT2 mRNA and protein were upregulated de novo in astrocytes. Live cell imaging of brain slices from mice following MCAo/R showed that astrocytes responded to modest increases in D-glucose by increasing intracellular Na+ and cell volume (cytotoxic edema), both of which were inhibited by the SGLT2 inhibitor, canagliflozin. The effect of canagliflozin was studied in three mouse models of stroke: non-diabetic and T2DM mice with a moderate ischemic insult (MCAo/R, 1/24 h) and non-diabetic mice with a severe ischemic insult (MCAo/R, 2/24 h). Canagliflozin reduced infarct volumes in models with moderate but not severe ischemic insults. However, canagliflozin significantly reduced hemispheric swelling and improved neurological function in all models tested. The ability of canagliflozin to reduce brain swelling regardless of an effect on infarct size has important translational implications, especially in large ischemic strokes.

Canagliflozin Inhibited the Activity of Hemolysin and Reduced the Inflammatory Response Caused by Streptococcus suis

Highly virulent Streptococcus suis (S. suis) infections can cause Streptococcal toxic shock-like syndrome (STSLS) in pigs and humans, in which an excessive inflammatory response causes severe damage. Hemolysin (SLY) is a major virulence factor of S. suis serotype 2 that produces pores in the target cell membrane, leading to cytoplasmic K+ efflux and activation of the NLRP3 inflammasome, ultimately causing STSLS. The critical aspect of hemolysin in the pathogenesis of S. suis type 2 makes it an attractive target for the development of innovative anti-virulence drugs. Here, we use the S. suis toxin protein (SLY) as a target for virtual screening. A compound called canagliflozin, a hypoglycemic agent, was identified through screening. Canagliflozin significantly inhibits the hemolytic activity of hemolysin. The results combined with molecular dynamics simulation, surface plasmon resonance, and nano differential scanning fluorimetry show that canagliflozin inhibits the hemolytic activity of SLY by binding to SLY. In addition, canagliflozin markedly reduced the release of SC19-induced inflammatory factors at the cellular level and in mice. Importantly, the combination of canagliflozin and ampicillin had a 90% success rate in mice, significantly greater than the therapeutic effect of ampicillin. The findings suggest that canagliflozin may be a promising new drug candidate for S. suis infections.

Simultaneous SGLT2 inhibition and caloric restriction improves insulin resistance and kidney function in OLETF rats

SGLT2 inhibitors (SGLT2i) are emerging as a novel therapy for type 2 diabetes due to their effective hypoglycemic and potential cardio- and nephroprotective effects, while caloric restriction (CR) is a common behavioral modification to improve adiposity and insulin resistance. Therefore, both interventions simultaneously may potentially further improve metabolic syndrome by enhancing carbohydrate metabolism. To test this hypothesis, cohorts of 10-week old, male Long Evans Tokushima Otsuka (LETO) and Otsuka Long Evans Tokushima Fatty (OLETF) rats were treated with SGLT2i (10 mg luseoglifozin/kg/day x 4 wks) (OLETF only) and/or 30% CR (2 wks at 12 weeks of age). CR maintained body mass in both strains while SGLT2i alone did not have any effect on body mass. Simultaneous treatments decreased SBP in OLETF vs SGLT2i alone, decreased insulin resistance index (IRI), and increased creatinine clearance vs OLETF ad lib. Conversely, CR decreased albuminuria independent of SGLT2i. In conclusion, SGLT2i treatment by itself did not elicit significant improvements in insulin resistance, kidney function or blood pressure. However, when combined with CR, these changes where more profound than with CR alone without inducing chronic hypoglycemia.

Effects of C2 hemisection on respiratory and cardiovascular functions in rats

High cervical spinal cord injuries induce permanent neuromotor and autonomic deficits. These injuries impact both central respiratory and cardiovascular functions through modulation of the sympathetic nervous system. So far, cardiovascular studies have focused on models of complete contusion or transection at the lower cervical and thoracic levels and diaphragm activity evaluations using invasive methods. The present study aimed to evaluate the impact of C2 hemisection on different parameters representing vital functions (i.e., respiratory function, cardiovascular, and renal filtration parameters) at the moment of injury and 7 days post-injury in rats. No ventilatory parameters evaluated by plethysmography were impacted during quiet breathing after 7 days post-injury, whereas permanent diaphragm hemiplegia was observed by ultrasound and confirmed by diaphragmatic electromyography in anesthetized rats. Interestingly, the mean arterial pressure was reduced immediately after C2 hemisection, with complete compensation at 7 days post-injury. Renal filtration was unaffected at 7 days post-injury; however, remnant systolic dysfunction characterized by a reduced left ventricular ejection fraction persisted at 7 days post-injury. Taken together, these results demonstrated that following C2 hemisection, diaphragm activity and systolic function are impacted up to 7 days post-injury, whereas the respiratory and cardiovascular systems display vast adaptation to maintain ventilatory parameters and blood pressure homeostasis, with the latter likely sustained by the remaining descending sympathetic inputs spared by the initial injury. A better broad characterization of the physiopathology of high cervical spinal cord injuries covering a longer time period post-injury could be beneficial for understanding evaluations of putative therapeutics to further increase cardiorespiratory recovery.

Critical Reanalysis of the Mechanisms Underlying the Cardiorenal Benefits of SGLT2 Inhibitors and Reaffirmation of the Nutrient Deprivation Signaling/Autophagy Hypothesis

SGLT2 (sodium-glucose cotransporter 2) inhibitors produce a distinctive pattern of benefits on the evolution and progression of cardiomyopathy and nephropathy, which is characterized by a reduction in oxidative and endoplasmic reticulum stress, restoration of mitochondrial health and enhanced mitochondrial biogenesis, a decrease in proinflammatory and profibrotic pathways, and preservation of cellular and organ integrity and viability. A substantial body of evidence indicates that this characteristic pattern of responses can be explained by the action of SGLT2 inhibitors to promote cellular housekeeping by enhancing autophagic flux, an effect that may be related to the action of these drugs to produce simultaneous upregulation of nutrient deprivation signaling and downregulation of nutrient surplus signaling, as manifested by an increase in the expression and activity of AMPK (adenosine monophosphate-activated protein kinase), SIRT1 (sirtuin 1), SIRT3 (sirtuin 3), SIRT6 (sirtuin 6), and PGC1-α (peroxisome proliferator-activated receptor γ coactivator 1-α) and decreased activation of mTOR (mammalian target of rapamycin). The distinctive pattern of cardioprotective and renoprotective effects of SGLT2 inhibitors is abolished by specific inhibition or knockdown of autophagy, AMPK, and sirtuins. In the clinical setting, the pattern of differentially increased proteins identified in proteomics analyses of blood collected in randomized trials is consistent with these findings. Clinical studies have also shown that SGLT2 inhibitors promote gluconeogenesis, ketogenesis, and erythrocytosis and reduce uricemia, the hallmarks of nutrient deprivation signaling and the principal statistical mediators of the ability of SGLT2 inhibitors to reduce the risk of heart failure and serious renal events. The action of SGLT2 inhibitors to augment autophagic flux is seen in isolated cells and tissues that do not express SGLT2 and are not exposed to changes in environmental glucose or ketones and may be related to an ability of these drugs to bind directly to sirtuins or mTOR. Changes in renal or cardiovascular physiology or metabolism cannot explain the benefits of SGLT2 inhibitors either experimentally or clinically. The direct molecular effects of SGLT2 inhibitors in isolated cells are consistent with the concept that SGLT2 acts as a nutrient surplus sensor, and thus, its inhibition causes enhanced nutrient deprivation signaling and its attendant cytoprotective effects, which can be abolished by specific inhibition or knockdown of AMPK, sirtuins, and autophagic flux.

Heart Failure with Preserved Ejection Fraction and Obstructive Sleep Apnea: A Novel Paradigm for Additional Cardiovascular Benefit of SGLT2 Inhibitors in Subjects With or Without Type 2 Diabetes

After examining the complex interplay between heart failure (HF) in its various clinical forms, metabolic disorders like nonalcoholic fatty liver disease (NAFLD), and obstructive sleep apnea (OSA) syndrome, in this mini-review we described possible favorable effects of sodium-glucose cotransporter 2 inhibitors (SGLT2is) on HF with preserved (i.e., ≥ 50%) ejection fraction (HFpEF) through enhanced cardiorenal function and visceral-subcutaneous body fat redistribution. In greater detail, on the basis of pathophysiological mechanisms underlying OSA onset and the direct positive SGLT2i effect on renal function benefiting chronic kidney disease, we emphasized the promising role of SGLT2is in prevention, rehabilitation, and treatment of patients with OSA regardless of coexisting type 2 diabetes (T2DM). Indeed, SGLT2is enhance lipolysis and fatty acid beta-oxidation. These phenomena might prevent OSA by reducing the size of visceral and subcutaneous adipose tissue and, as proven in humans and animals with T2DM, counteract NAFLD onset and progression. The aforementioned mechanisms may represent an additional SGLT2i cardioprotective effect in terms of HFpEF prevention in patients with OSA, whose NAFLD prevalence is estimated to be over 50%.

Beneficial effects of SGLT2 inhibitor on metabolic inflexibility and visceral fat amount in animal model of obese type 2 diabetes

Background

Obesity and type 2 diabetes mellitus (T2DM) are often accompanied with a disrupted diurnal rhythm of eating and sustained anabolic state, leading to metabolic inflexibility. In the present study, we plan to investigate effects of a sodium glucose co-transporter 2 (SGLT2) inhibitor, canagliflozin (CANA), on such a metabolic inflexibility, especially on fat metabolism, in the obese type 2 diabetic rats.

Materials and methods

Five-week-old male SDT (Spontaneously Diabetic Torii) fatty rats as a model of obesity and T2DM and Sprague-Dawley (SD) rats were treated by either CANA (10 mg/kg) or saline (vehicle) orally for 14 days. Then, after the measurement of respiratory quotient (RQ) and visceral and subcutaneous fat volumes, rats were euthanized and blood and tissue samples were collected.

Results

The treatment by CANA significantly enhanced β-ketone concentration in the blood during light period in the SDT fatty rats with no effect on blood glucose concentration. The CANA treatment significantly reduced visceral fat volume in the SDT fatty rats. A diurnal rhythm of RQ was severely disrupted and persistently high throughout the day in the vehicle-treated SDT fatty rats. By the administration of CANA clearly restored the disrupted diurnal rhythm of RQ with a revival of the nadir during light period. Quantitative real-time RT-PCR revealed a significant increase of AMP-activated protein kinase and decrease of acetyl-CoA carboxylase-1 expression in the liver, and a significant increase of hormone sensitive lipase and uncoupling protein-2 expression in the white adipose tissue by the treatment of CANA in the SDT fatty rats.

Conclusion

CANA as a SGLT2i reduced visceral fat amount via the enhancement of fat oxidation during the light period, leading to an amelioration of metabolic inflexibility in an obese diabetic model. A novel mechanism of CANA prompts the possibility that this new class of anti-diabetic agent could be a promising anti-obesity agent as well.

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SGLT2i reduced visceral fat independent of its effect on urinary glucose excretion.

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SGLT2i increased blood ketone concentration during light period.

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Concomitantly, RQ during light period was decreased, reviving a diurnal RQ rhythm.

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Changes in relevant molecules were observed towards fat oxidation.

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SGLT2i effectively corrected metabolic inflexibility in an obese diabetic model.

Differential In Vitro Effects of SGLT2 Inhibitors on Mitochondrial Oxidative Phosphorylation, Glucose Uptake and Cell Metabolism

(1) The cardio-reno-metabolic benefits of the SGLT2 inhibitors canagliflozin (cana), dapagliflozin (dapa), ertugliflozin (ertu), and empagliflozin (empa) have been demonstrated, but it remains unclear whether they exert different off-target effects influencing clinical profiles. (2) We aimed to investigate the effects of SGLT2 inhibitors on mitochondrial function, cellular glucose-uptake (GU), and metabolic pathways in human-umbilical-vein endothelial cells (HUVECs). (3) At 100 µM (supra-pharmacological concentration), cana decreased ECAR by 45% and inhibited GU (IC5o: 14 µM). At 100 µM and 10 µM (pharmacological concentration), cana increased the ADP/ATP ratio, whereas dapa and ertu (3, 10 µM, about 10× the pharmacological concentration) showed no effect. Cana (100 µM) decreased the oxygen consumption rate (OCR) by 60%, while dapa decreased it by 7%, and ertu and empa (all 100 µM) had no significant effect. Cana (100 µM) inhibited GLUT1, but did not significantly affect GLUTs’ expression levels. Cana (100 µM) treatment reduced glycolysis, elevated the amino acids supplying the tricarboxylic-acid cycle, and significantly increased purine/pyrimidine-pathway metabolites, in contrast to dapa (3 µM) and ertu (10 µM). (4) The results confirmed cana´s inhibition of mitochondrial activity and GU at supra-pharmacological and pharmacological concentrations, whereas the dapa, ertu, and empa did not show effects even at supra-pharmacological concentrations. At supra-pharmacological concentrations, cana (but not dapa or ertu) affected multiple cellular pathways and inhibited GLUT1.

Canagliflozin Ameliorates Nonalcoholic Fatty Liver Disease by Regulating Lipid Metabolism and Inhibiting Inflammation through Induction of Autophagy

PURPOSE

Nonalcoholic fatty liver disease (NAFLD) is closely associated with metabolic diseases, including obesity and diabetes, and has gradually become the most common cause of chronic liver disease. We investigated the effects of sodium glucose cotransporter 2 (SGLT2) inhibitor canagliflozin on NAFLD in high-fat diet (HFD)-induced obese mice and possible underlying mechanisms.

MATERIALS AND METHODS

Male C57BL/6 mice were fed a normal-diet, HFD, or HFD with canagliflozin for 14 weeks. AML-12 hepatocytes were treated with canagliflozin. Expression of related pathways was assessed.

RESULTS

Canagliflozin administration reduced body weight and fat mass, compared with HFD alone. Canagliflozin improved glucose and lipid metabolic disorders. Compared with HFD-fed mice, liver weight, serum alanine transaminase (ALT) levels, and hepatic lipid accumulation were decreased after canagliflozin administration. Additionally, canagliflozin upregulated lipolysis markers (CPT1a, ACOX1, and ACADM), downregulated lipogenesis markers (SREBP-1c and FASN), and suppressed the production of inflammatory cytokines (TNFα, MCP1, IL-1β, and IL-6), consistent with significantly increased LC3 II/I and Atg7 levels in the liver following canagliflozin treatment. In vitro, canagliflozin increased CPT1a, ACOX1, and ACADM expression, decreased SREBP-1c and FASN protein expression, and reduced TNFα, MCP1, IL-1β, and IL-6 mRNA levels in lipid mixture (LM)-induced hepatocytes in a dose-dependent manner. These changes were reversed by 3-MA, an autophagy inhibitor.

CONCLUSION

Our findings suggest that canagliflozin ameliorates the pathogenesis of NAFLD by regulating lipid metabolism and inhibiting inflammation, which may be associated with its promotion of autophagy.

Efficacy and safety of sodium-glucose co-transporter 2 inhibitors in the elderly versus non-elderly patients with type 2 diabetes mellitus: a meta-analysis

This meta-analysis was performed to compare the influence of sodium-glucose co-transporter 2 inhibitors (SGLT2i) on the efficacy and safety of elderly patients with type 2 diabetes with the young ones. PubMed, Medline, Web of Science, EMbase, and Cochrane Library were searched for literature published before March 2020 to identify studies comparing efficacy and safety of SGLT2i in elderly diabetes patients (≥65 years) and young controls (<65 years). A fixed or random-effect model was used to calculate the summary standard means difference and odds ratios. A total of 13 articles with data for 86,433 participants were included. Old patients receiving SGLT2i had a smaller reduction in hemoglobin A1c (SMD = -0.07, 95% CI -0.14 to -0.00, p = 0.044) than young ones. They had higher incidence of serious adverse events (SAEs) (OR 1.78, 95% CI 1.25-2.55, p = 0.001), AE leading to discontinuation (OR 2.34, 95%CI 1.53-3.59, p = 0.000), volume depletion (OR 2.80, 95% CI 1.82-4.32, p = 0.000) , and urinary tract infections (OR 1.37, 95% CI 1.18-1.60, p = 0.000), and renal function impairment (OR 2.61, 95% CI 1.78-3.81, p = 0.000) than young patients, and there was a opposite result in genital mycotic infections (OR 0.69, 95% CI 0.55-0.87, p = 0.002). No significant differences were recorded in the reduction of fasting blood glucose, blood pressure, body weight, and in incidence of overall AEs and fracture. In summary, relatively satisfying efficacy was observed in the elderly patients receiving SGLT2i. Although some AEs were more prevalent among older patients, the majority of them were generally mild.

Role of Sodium-Glucose Co-Transporter 2 Inhibitors in the Regulation of Inflammatory Processes in Animal Models

Sodium-glucose co-transporter 2 inhibitors, also known as gliflozins, were developed as a novel class of anti-diabetic agents that promote glycosuria through the prevention of glucose reabsorption in the proximal tubule by sodium-glucose co-transporter 2. Beyond the regulation of glucose homeostasis, they resulted as being effective in different clinical trials in patients with heart failure, showing a strong cardio-renal protective effect in diabetic, but also in non-diabetic patients, which highlights the possible existence of other mechanisms through which gliflozins could be exerting their action. So far, different gliflozins have been approved for their therapeutic use in T2DM, heart failure, and diabetic kidney disease in different countries, all of them being diseases that have in common a deregulation of the inflammatory process associated with the pathology, which perpetuates and worsens the disease. This inflammatory deregulation has been observed in many other diseases, which led the scientific community to have a growing interest in the understanding of the biological processes that lead to or control inflammation deregulation in order to be able to identify potential therapeutic targets that could revert this situation and contribute to the amelioration of the disease. In this line, recent studies showed that gliflozins also act as an anti-inflammatory drug, and have been proposed as a useful strategy to treat other diseases linked to inflammation in addition to cardio-renal diseases, such as diabetes, obesity, atherosclerosis, or non-alcoholic fatty liver disease. In this work, we will review recent studies regarding the role of the main sodium-glucose co-transporter 2 inhibitors in the control of inflammation.

A Deep Insight Into Regulatory T Cell Metabolism in Renal Disease: Facts and Perspectives

Kidney disease encompasses a complex set of diseases that can aggravate or start systemic pathophysiological processes through their complex metabolic mechanisms and effects on body homoeostasis. The prevalence of kidney disease has increased dramatically over the last two decades. CD4⁺CD25⁺ regulatory T (Treg) cells that express the transcription factor forkhead box protein 3 (Foxp3) are critical for maintaining immune homeostasis and preventing autoimmune disease and tissue damage caused by excessive or unnecessary immune activation, including autoimmune kidney diseases. Recent studies have highlighted the critical role of metabolic reprogramming in controlling the plasticity, stability, and function of Treg cells. They are also likely to play a vital role in limiting kidney transplant rejection and potentially promoting transplant tolerance. Metabolic pathways, such as mitochondrial function, glycolysis, lipid synthesis, glutaminolysis, and mammalian target of rapamycin (mTOR) activation, are involved in the development of renal diseases by modulating the function and proliferation of Treg cells. Targeting metabolic pathways to alter Treg cells can offer a promising method for renal disease therapy. In this review, we provide a new perspective on the role of Treg cell metabolism in renal diseases by presenting the renal microenvironment、relevant metabolites of Treg cell metabolism, and the role of Treg cell metabolism in various kidney diseases.

Effects of an SGLT Inhibitor on the Production, Toxicity, and Elimination of Gut-Derived Uremic Toxins: A Call for Additional Evidence

Sodium–glucose cotransporter (SGLT) inhibitors are a class of oral hypoglycemic agents, which, in recent years, have been shown to improve renal and cardiovascular outcomes in patients with diabetic and non-diabetic chronic kidney disease. There remains considerable debate regarding the potential glucose-independent mechanisms by which these benefits are conferred. SGLT inhibitors, to a variable extent, impair small intestinal glucose absorption, facilitating the delivery of glucose into the colon. This suppresses protein fermentation, and thus the generation of uremic toxins such as phenols and indoles. It is acknowledged that such a shift in gut microbial metabolism yields health benefits for the host. SGLT inhibition, in addition, may be hypothesized to foster the renal clearance of protein-bound uremic toxins. Altered generation and elimination of uremic toxins may be in the causal pathway between SGLT inhibition and improved cardiometabolic health. Present review calls for additional research.

Antioxidant Roles of SGLT2 Inhibitors in the Kidney

The reduction-oxidation (redox) system consists of the coupling and coordination of various electron gradients that are generated thanks to serial reduction-oxidation enzymatic reactions. These reactions happen in every cell and produce radical oxidants that can be mainly classified into reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS and RNS modulate cell-signaling pathways and cellular processes fundamental to normal cell function. However, overproduction of oxidative species can lead to oxidative stress (OS) that is pathological. Oxidative stress is a main contributor to diabetic kidney disease (DKD) onset. In the kidney, the proximal tubular cells require a high energy supply to reabsorb proteins, metabolites, ions, and water. In a diabetic milieu, glucose-induced toxicity promotes oxidative stress and mitochondrial dysfunction, impairing tubular function. Increased glucose level in urine and ROS enhance the activity of sodium/glucose co-transporter type 2 (SGLT2), which in turn exacerbates OS. SGLT2 inhibitors have demonstrated clear cardiovascular benefits in DKD which may be in part ascribed to the generation of a beneficial equilibrium between oxidant and antioxidant mechanisms.

Diabetes, Heart Failure and Beyond: Elucidating the Cardioprotective Mechanisms of Sodium Glucose Cotransporter 2 (SGLT2) Inhibitors

Approximately 5 million individuals in the US are living with congestive heart failure (CHF), with 650,000 new cases being diagnosed every year. CHF has a multifactorial etiology, ranging from coronary artery disease, hypertension, valvular abnormalities and diabetes mellitus. Currently, guidelines by the American College of Cardiology advocate the use of angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers, β-blockers, diuretics, aldosterone antagonists, and inotropes for the medical management of heart failure. The sodium glucose cotransporter 2 (SGLT2) inhibitors are a class of drug that have been widely used in the management of type 2 diabetes mellitus that work by inhibiting the reabsorption of glucose in the proximal convoluted tubule. Since the EMPA-REG OUTCOME trial, several studies have demonstrated the benefits of SGLT2 inhibitors in reducing cardiovascular risk related to heart failure. While the cardiovascular benefits could be explained by their ability to reduce weight, improve glycemic index and lower blood pressure, several recent trials have suggested that SGLT2 inhibitors exhibit pleiotropic effects that underlie their cardioprotective properties. These findings have led to an expansion in preclinical and clinical research aiming to understand the mechanisms by which SGLT2 inhibitors improve heart failure outcomes.

Effects of canagliflozin on human myocardial redox signalling: clinical implications

AIMS

Recent clinical trials indicate that sodium-glucose cotransporter 2 (SGLT2) inhibitors improve cardiovascular outcomes in heart failure patients, but the underlying mechanisms remain unknown. We explored the direct effects of canagliflozin, an SGLT2 inhibitor with mild SGLT1 inhibitory effects, on myocardial redox signalling in humans.

METHODS AND RESULTS

Study 1 included 364 patients undergoing cardiac surgery. Right atrial appendage biopsies were harvested to quantify superoxide (O2.-) sources and the expression of inflammation, fibrosis, and myocardial stretch genes. In Study 2, atrial tissue from 51 patients was used ex vivo to study the direct effects of canagliflozin on NADPH oxidase activity and nitric oxide synthase (NOS) uncoupling. Differentiated H9C2 and primary human cardiomyocytes (hCM) were used to further characterize the underlying mechanisms (Study 3). SGLT1 was abundantly expressed in human atrial tissue and hCM, contrary to SGLT2. Myocardial SGLT1 expression was positively associated with O2.- production and pro-fibrotic, pro-inflammatory, and wall stretch gene expression. Canagliflozin reduced NADPH oxidase activity via AMP kinase (AMPK)/Rac1signalling and improved NOS coupling via increased tetrahydrobiopterin bioavailability ex vivo and in vitro. These were attenuated by knocking down SGLT1 in hCM. Canagliflozin had striking ex vivo transcriptomic effects on myocardial redox signalling, suppressing apoptotic and inflammatory pathways in hCM.

CONCLUSIONS

We demonstrate for the first time that canagliflozin suppresses myocardial NADPH oxidase activity and improves NOS coupling via SGLT1/AMPK/Rac1 signalling, leading to global anti-inflammatory and anti-apoptotic effects in the human myocardium. These findings reveal a novel mechanism contributing to the beneficial cardiac effects of canagliflozin.

SGLT2 Inhibitors and the Clinical Implications of Associated Weight Loss in Type 2 Diabetes: A Narrative Review

INTRODUCTION

The obesity epidemic is closely linked to the rising prevalence of type 2 diabetes (T2D). Body weight reduction remains an important challenge in patients with T2D, as it requires changing their overall metabolic control. Of all glucose-lowering therapies, only sodium-glucose cotransporter 2 inhibitors (SGLT2is) and glucagon-like peptide 1 receptor agonists (GLP-1 RAs) consistently result in weight improvement. Moreover, the same two classes have important cardiovascular and renal benefits. We summarize the key available information related to the weight loss effect of SGLT2is in T2D, focusing on the unexploited potential of these drugs.

METHODS

Data on weight change with SGLT2is in patients with T2D were extracted from published cardiovascular outcomes trials (CVOTs). A discussion on patient perspectives about weight change is based on key preclinical and clinical trials, meta-analyses, and reviews and is supplemented by the authors' clinical judgment and research experience in the field.

RESULTS

SGLT2is have a unique mode of action resulting in caloric loss through glycosuria. The anticipated weight loss with SGLT2is is not reflected in clinical trial results. There is a discrepancy between the magnitude of improvement in glycemic control and the weight loss, cardiovascular, and renal benefits obtained in large clinical trials.

CONCLUSION

The relationships between the magnitude of weight loss, improvement in glycemic control, and cardiorenal benefits with SGLT2i are still unclear. Potential mechanisms other than simple glycemic efficacy should be revealed and explained. Better weight control may be achieved if adequately intensive lifestyle changes are implemented and monitored in the T2D population treated with SGLT2is.

Possible Preventative/Rehabilitative Role of Gliflozins in OSA and T2DM. A Systematic Literature Review-Based Hypothesis

Obstructive sleep apnoea (OSA) is characterized by frequent apnoea episodes during sleep due to upper airway obstruction. The present review summarizes current knowledge on inter-relationships between OSA and type 2 diabetes mellitus (T2DM) and suggests the former as a possible target for sodium-glucose co-transporter-2 inhibitors (SGLT-2i). Based on pathophysiological mechanisms underlying OSA onset and renal SGLT-2 effects, we suggest that SGLT-2i indications might expand beyond current ones, including glucose, lipids, uric acid, blood pressure, and body weight control as well as chronic heart failure and kidney disease prevention.

Swertisin, a novel SGLT2 inhibitor, with improved glucose homeostasis for effective diabetes therapy

Failing pancreas and subsequent loss of pancreatic β cells worsen diabetic conditions which are further alleviated by the mounting up of glucose levels. Inhibition of sodium glucose cotransporter 2 (SGLT2) in the kidney responsible for glucose reabsorption strikingly reduces blood glucose levels. Bioactive swertisin showed a promising glucose-lowering effect. Hence, we aimed to mechanistically dissect the glucose lowering property of swertisin. A systematic in silico, in vitro, and in vivo approach was directed for target analysis of swertisin. Molecular docking was performed with Swertisn-hSGLT2 complex. Glucose uptake assay and protein expression for SGLT2 and regulatory proteins were performed under swertisin effect. Various physiological and metabolic parameters were evaluated in STZ induced BALB/c mice using swertisin treatment. SGLT2 expression was evaluated in the kidney tissue of mice. Swertisn-hSGLT2 molecularly docked complex showed similar binding energy compared to the Canagliflozin-hSGLT2 complex. Swertisin inhibited glucose uptake and decreased expression of SGLT2 in HEK293 cells. Swertisin does not affect GLUT mediated glucose transport. Swertisin treated diabetic mice demonstrated remarkable improvement in overall glucose homeostasis. Reduced expression of SGLT2 was found in kidney tissue along with reduced PKC expression which is one of the key regulators of SGLT2. Our study explored SGLT2 as a selective target of swertisin for its swift glucose-lowering action which not only inhibits SGLT2 but also reduces its expression in diabetic condition. Thus, the potential property of swertisin as a glucose-lowering agent is remarkable which points towards the likelihood of a wider avenue of diabetes therapy.

Novel Approaches to Restore Pancreatic Beta-Cell Mass and Function

Beta-cell dysfunction and beta-cell death are critical events in the development of type 2 diabetes mellitus (T2DM). Therefore, the goals of modern T2DM management have shifted from merely restoring normoglycemia to maintaining or regenerating beta-cell mass and function. In this review we summarize current and novel approaches to achieve these goals, ranging from lifestyle interventions to N-methyl-D-aspartate receptor (NMDAR) antagonism, and discuss the mechanisms underlying their effects on beta-cell physiology and glycemic control. Notably, timely intervention seems critical, but not always strictly required, to maximize the effect of any approach on beta-cell recovery and disease progression. Conventional antidiabetic medications are not disease-modifying in the sense that the disease does not progress or reoccur while on treatment or thereafter. More invasive approaches, such as bariatric surgery, are highly effective in restoring normoglycemia, but are reserved for a rather small proportion of obese individuals and sometimes associated with serious adverse events. Finally, we recapitulate the broad range of effects mediated by peripheral NMDARs and discuss recent evidence on the potential of NMDAR antagonists to be developed as a novel class of antidiabetic drugs. In the future, a more refined assessment of disease risk or disease subtype might enable more targeted therapies to prevent or treat diabetes.

Inhibition of the sodium-glucose co-transporter SGLT2 by canagliflozin ameliorates diet-induced obesity by increasing intra-adipose sympathetic innervation

BACKGROUND AND PURPOSE

Inhibition of the sodium-glucose cotransporter 2 (SGLT2) induces hypoglycaemia by increasing urinary glucose excretion and increasing the use of fat. However, the underlying mechanism is poorly understood. This study was aimed to determine the effects of canagliflozin, a selective SGLT2 inhibitor, on diet-induced obesity and the underlying mechanism(s).

EXPERIMENTAL APPROACH

Adult C57BL/6J male mice were fed with a standard chow diet or high-fat diet supplemented with vehicle or canagliflozin. Whole body energy expenditure was monitored by metabolic cages, noradrenaline levels were measured by HPLC, glucose uptake was measured by PET/CT, and mRNA and protein expression were measured by RT-PCR and western blotting analysis.

KEY RESULTS

Mice treated with canagliflozin were resistant to high-fat diet-induced obesity and its metabolic consequences. Canagliflozin treatment decreased fat mass and increased energy expenditure via increasing thermogenesis and lipolysis in adipose tissue. Mechanistically, SGLT2 inhibition by canagliflozin elevated adipose sympathetic innervation and fat mobilization via a β₃ -adrenoceptor-cAMP-PKA signalling pathway. Finally, we showed that canagliflozin improved insulin resistance and hepatic steatosis in mice fed with a high-fat diet.

CONCLUSIONS AND IMPLICATIONS

Chronic inhibition of SGLT2 increased energy consumption by increasing intra-adipose sympathetic innervation to counteract diet-induced obesity. The present study reveals a new therapeutic function for SGLT2 inhibitors in regulating energy homeostasis.

Signaling pathways and proteins targeted by antidiabetic chalcones

Chalcones have shown a broad spectrum of biological activities with clinical potential against various diseases. The biological activities are mainly attributed to the presence of α, β-unsaturated carbonyl system, perceived as potential Michael acceptors. In this review, we discussed the antioxidant potential of chalcones and elucidated the mechanisms of pathways and proteins such as carbohydrate digestive enzymes (α-amylase and α-glucosidase), aldose reductase, SGLT-2, and Nrf2 that are targeted by antidiabetic chalcones. In addition to their insulin mimetic potential, we explore the major molecular targets of chalcones and discuss the biochemical and therapeutic implication of modulating these targets. Finally, we dwell on the opulence of the literature and envisage how RNA interference-mediated gene silencing technique and in silico molecular docking could be exploited in the search for novel and more efficacious antidiabetic chalcones.

Canagliflozin extends life span in genetically heterogeneous male but not female mice

Canagliflozin (Cana) is an FDA-approved diabetes drug that protects against cardiovascular and kidney diseases. It also inhibits the sodium glucose transporter 2 by blocking renal reuptake and intestinal absorption of glucose. In the context of the mouse Interventions Testing Program, genetically heterogeneous mice were given chow containing Cana at 180 ppm at 7 months of age until their death. Cana extended median survival of male mice by 14%. Cana also increased by 9% the age for 90th percentile survival, with parallel effects seen at each of 3 test sites. Neither the distribution of inferred cause of death nor incidental pathology findings at end-of-life necropsies were altered by Cana. Moreover, although no life span benefits were seen in female mice, Cana led to lower fasting glucose and improved glucose tolerance in both sexes, diminishing fat mass in females only. Therefore, the life span benefit of Cana is likely to reflect blunting of peak glucose levels, because similar longevity effects are seen in male mice given acarbose, a diabetes drug that blocks glucose surges through a distinct mechanism, i.e., slowing breakdown of carbohydrate in the intestine. Interventions that control daily peak glucose levels deserve attention as possible preventive medicines to protect from a wide range of late-life neoplastic and degenerative diseases.

The SGLT2 inhibitor canagliflozin extends median life span of male mice but does not increase life span of female mice.

Glucose transporters in pancreatic islets

The fine-tuning of glucose uptake mechanisms is rendered by various glucose transporters with distinct transport characteristics. In the pancreatic islet, facilitative diffusion glucose transporters (GLUTs), and sodium-glucose cotransporters (SGLTs) contribute to glucose uptake and represent important components in the glucose-stimulated hormone release from endocrine cells, therefore playing a crucial role in blood glucose homeostasis. This review summarizes the current knowledge about cell type-specific expression profiles as well as proven and putative functions of distinct GLUT and SGLT family members in the human and rodent pancreatic islet and further discusses their possible involvement in onset and progression of diabetes mellitus. In context of GLUTs, we focus on GLUT2, characterizing the main glucose transporter in insulin-secreting β-cells in rodents. In addition, we discuss recent data proposing that other GLUT family members, namely GLUT1 and GLUT3, render this task in humans. Finally, we summarize latest information about SGLT1 and SGLT2 as representatives of the SGLT family that have been reported to be expressed predominantly in the α-cell population with a suggested functional role in the regulation of glucagon release.

Sodium-glucose cotransporter-2 inhibitors: Understanding the mechanisms for therapeutic promise and persisting risks

In a healthy person, the kidney filters nearly 200 g of glucose per day, almost all of which is reabsorbed. The primary transporter responsible for renal glucose reabsorption is sodium-glucose cotransporter-2 (SGLT2). Based on the impact of SGLT2 to prevent renal glucose wasting, SGLT2 inhibitors have been developed to treat diabetes and are the newest class of glucose-lowering agents approved in the United States. By inhibiting glucose reabsorption in the proximal tubule, these agents promote glycosuria, thereby reducing blood glucose concentrations and often resulting in modest weight loss. Recent work in humans and rodents has demonstrated that the clinical utility of these agents may not be limited to diabetes management: SGLT2 inhibitors have also shown therapeutic promise in improving outcomes in heart failure, atrial fibrillation, and, in preclinical studies, certain cancers. Unfortunately, these benefits are not without risk: SGLT2 inhibitors predispose to euglycemic ketoacidosis in those with type 2 diabetes and, largely for this reason, are not approved to treat type 1 diabetes. The mechanism for each of the beneficial and harmful effects of SGLT2 inhibitors-with the exception of their effect to lower plasma glucose concentrations-is an area of active investigation. In this review, we discuss the mechanisms by which these drugs cause euglycemic ketoacidosis and hyperglucagonemia and stimulate hepatic gluconeogenesis as well as their beneficial effects in cardiovascular disease and cancer. In so doing, we aim to highlight the crucial role for selecting patients for SGLT2 inhibitor therapy and highlight several crucial questions that remain unanswered.

Ipragliflozin-induced improvement of liver steatosis in obese mice may involve sirtuin signaling

BACKGROUND

Sodium glucose cotransporter 2 (SGLT2) inhibitors are newly developed oral antidiabetic drugs. SGLT2 is primarily expressed in the kidneys and reabsorbs approximately 90% of the glucose filtered by the renal glomeruli. SGLT2 inhibitors lower glucose levels independently of insulin action by facilitating urinary glucose excretion. The SGLT2 inhibitor ipragliflozin has reportedly improved liver steatosis in animal models and clinical studies. However, the mechanisms by which SGLT2 inhibitors improve liver steatosis are not fully understood.

AIM

To investigate the ameliorative effects of ipragliflozin on liver steatosis and the mechanisms of these effects in obese mice.

METHODS

We analyzed 8-wk-old male obese (ob/ob) mice that were randomly divided into a group receiving a normal chow diet and a group receiving a normal chow diet supplemented with ipragliflozin (3 mg/kg or 10 mg/kg) for 4 wk. We also analyzed their lean sex-matched littermates receiving a normal chow diet as another control group. Body weight and liver weight were evaluated, and liver histology, immunoblotting, and reverse transcription-polymerase chain reaction analyses were performed.

RESULTS

Hepatic lipid accumulation was significantly ameliorated in ob/ob mice treated with 10 mg/kg ipragliflozin compared to untreated ob/ob mice irrespective of body weight changes. Ipragliflozin had no appreciable effects on hepatic oxidative stress-related gene expression levels or macrophage infiltration, but significantly reduced hepatic interleukin-1β (IL-1β) mRNA expression levels. Ipragliflozin increased both the mRNA and protein expression levels of sirtuin 1 (SIRT1) in the liver. The hepatic mRNA levels of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), peroxisome proliferator-activated receptor α (PPARα), and fibroblast growth factor-21 (FGF21) were also significantly higher in ipragliflozin-treated ob/ob mice than in untreated ob/ob mice.

CONCLUSION

Our study suggests that the liver steatosis-ameliorating effects of ipragliflozin in ob/ob mice may be mediated partly by hepatic SIRT1 signaling, possibly through the PGC-1α/PPARα-FGF21 pathway.

Beneficial effects of combination therapy of canagliflozin and teneligliptin on diabetic polyneuropathy and β-cell volume density in spontaneously type 2 diabetic Goto-Kakizaki rats

AIMS

Parasympathetic nerve (PN) signaling plays a crucial role in the maintenance of pancreatic β-cell volume density (V_β). PN may be pathologically affected in diabetic polyneuropathy (DPN). However, the association between the reduction of PNs in islets and V_β and the therapeutic effects of a DPP4 inhibitor (DPP4i) and an SGLT2 inhibitor (SGLT2i) in nonobese type 2 diabetes mellitus (T2DM) Goto-Kakizaki rats (GK) have not been investigated.

MATERIALS AND METHODS

We divided 5-week old male GK and Wistar rats (W) into a DPP4i-treated group (GKTe), SGLT2i-treated group (GKCa), and combination-treated group (GKCaTe). After 25 weeks, the pancreata was pathologically evaluated.

RESULTS

V_β in GK was significantly decreased (p < 0.01 vs. W), whereas V_β was the most well preserved in GKCaTe (p < 0.05 vs. GKTe), followed by GKTe (p < 0.05 vs. GK). The decreased amount of PNs in the islets and intraepidermal nerve fiber density (IENFD) in GK was significantly improved in the treated groups compared with GK (p < 0.05 vs. GKCa and GKTe and p < 0.01 vs. GKCaTe). PN density and IENFD were significantly correlated with V_β (r = 0.55, p < 0.01 and r = 0.54, p < 0.01, respectively). IENFD was identified as a surrogate marker for the prediction of V_β (cutoff value, 16.39).

CONCLUSIONS

The combination therapy of DPP4i and SGLT2i improved V_β accompanied by PNs density and IENFD. IENFD was proportionally correlated with V_β. Therefore, the prevention of DPN development may be concurrently beneficial for the preservation of V_β in nonobese T2DM.

Combined effect of canagliflozin and exercise training on high-fat diet-fed mice

Sodium-glucose cotransporter 2 inhibitors (SGLT2is) have been reported to improve obesity, diabetes, and nonalcoholic fatty liver disease (NAFLD) in addition to exercise training, whereas the combined effects remain to be elucidated fully. We investigated the effect of the combination of the SGLT2i canagliflozin (CAN) and exercise training in high-fat diet-induced obese mice. High-fat diet-fed mice were housed in normal cages (sedentary; Sed) or wheel cages (WCR) with or without CAN (0.03% of diet) for 4 wk. The effects on obesity, glucose metabolism, and hepatic steatosis were evaluated in four groups (Control/Sed, Control/WCR, CAN/Sed, and CAN/WCR). Numerically additive improvements were found in body weight, body fat mass, blood glucose, glucose intolerance, insulin resistance, and the fatty liver of the CAN/WCR group, whereas CAN increased food intake and reduced running distance. Exercise training alone, CAN alone, or both did not change the weight of skeletal muscle, but microarray analysis showed that each resulted in a characteristic change of gene expression in gastrocnemius muscle. In particular, in the CAN/WCR group, there was acceleration of the angiogenesis pathway and suppression of the adipogenesis pathway compared with the CAN/Sed group. In conclusion, the combination of an SGLT2i and exercise training improves obesity, insulin resistance, and NAFLD in an additive manner. Changes of gene expression in skeletal muscle may contribute, at least in part, to the improvement of obesity and insulin sensitivity.

Combined Treatment with Sodium-Glucose Cotransporter-2 Inhibitor (Canagliflozin) and Dipeptidyl Peptidase-4 Inhibitor (Teneligliptin) Alleviates NASH Progression in A Non-Diabetic Rat Model of Steatohepatitis

Hepatocellular carcinoma (HCC) is the strongest independent predictor of mortality in non-alcoholic steatohepatitis (NASH)-related cirrhosis. The effects and mechanisms of combination of sodium-dependent glucose cotransporter inhibitor and canagliflozin (CA) and dipeptidyl peptidase-4 inhibitor and teneligliptin (TE) on non-diabetic NASH progression were examined. CA and TE suppressed choline-deficient, L-amino acid-defined diet-induced hepatic fibrogenesis and carcinogenesis. CA alone or with TE significantly decreased proinflammatory cytokine expression. CA and TE significantly attenuated hepatic lipid peroxidation. In vitro studies showed that TE alone or with CA inhibited cell proliferation and TGF-β1 and α1 (I)-procollagen mRNA expression in Ac-HSCs. CA+TE inhibited liver fibrogenesis by attenuating hepatic lipid peroxidation and inflammation and by inhibiting Ac-HSC proliferation with concomitant attenuation of hepatic lipid peroxidation. Moreover, CA+TE suppressed in vivo angiogenesis and oxidative DNA damage. CA or CA+TE inhibited HCC cells and human umbilical vein endothelial cell (HUVEC) proliferation. CA+TE suppressed vascular endothelial growth factor expression and promoted increased E-cadherin expression in HUVECs. CA+TE potentially exerts synergistic effects on hepatocarcinogenesis prevention by suppressing HCC cell proliferation and angiogenesis and concomitantly reducing oxidative stress and by inhibiting angiogenesis with attenuation of oxidative stress. CA+TE showed chemopreventive effects on NASH progression compared with single agent in non-diabetic rat model of NASH, concurrent with Ac-HSC and HCC cell proliferation, angiogenesis oxidative stress, and inflammation. Both agents are widely, safely used in clinical practice; combined treatment may represent a potential strategy against NASH.

Canagliflozin Prevents Diabetes-Induced Vascular Dysfunction in ApoE-Deficient Mice

Aim: Recent studies have demonstrated that selective sodium–glucose cotransporter 2 inhibitors (SGLT2is) reduce cardiovascular events, although their mechanism remains obscure. We examined the effect of canagliflozin, an SGLT2i, on atherogenesis and investigated its underlying mechanism.

Method: Canagliflozin (30 mg/kg/day) was administered by gavage to streptozotocin-induced diabetic apolipoprotein E-deficient (ApoE^−/−) mice. Sudan IV staining was performed at the aortic arch. Immunostaining, quantitative RT-PCR, and vascular reactivity assay were performed using the aorta. In vitro experiments using human umbilical vein endothelial cells (HUVECs) were also performed.

Result: Canagliflozin decreased blood glucose (P < 0.001) and total cholesterol (P < 0.05) levels. Sudan IV staining showed that 12-week canagliflozin treatment decreased atherosclerotic lesions (P < 0.05). Further, 8-week canagliflozin treatment ameliorated endothelial dysfunction, as determined by acetylcholine-induced vasodilation (P < 0.05), and significantly reduced the expressions of inflammatory molecules such as ICAM-1 and VCAM-1 in the aorta at the RNA and protein levels. Canagliflozin also reduced the expressions of NADPH oxidase subunits such as NOX2 and p22phox in the aorta and reduced urinary excretion of 8-OHdG, suggesting a reduction in oxidative stress. Methylglyoxal, a precursor of advanced glycation end products, increased the expressions of ICAM-1 and p22phox in HUVECs (P < 0.05, both). Methylglyoxal also decreased the phosphorylation of eNOS^Ser1177 and Akt but increased the phosphorylation of eNOS^Thr495 and p38 MAPK in HUVECs.

Conclusion: Canagliflozin prevents endothelial dysfunction and atherogenesis in diabetic ApoE^−/− mice. Anti-inflammatory and antioxidative potential due to reduced glucose toxicity to endothelial cells might be its underlying mechanisms.

Effects of Sodium-Glucose Cotransporter 2 Inhibition on Glucose Metabolism, Liver Function, Ascites, and Hemodynamics in a Mouse Model of Nonalcoholic Steatohepatitis and Type 2 Diabetes

Many blood glucose-lowering drugs cannot be used once patients with type 2 diabetes (T2D) and nonalcoholic fatty liver disease develop nonalcoholic steatohepatitis (NASH). Therefore, such patients often require insulin treatment. We aimed to determine the effect of sodium-glucose cotransporter 2 inhibitor (SGLT2i) dapagliflozin monotherapy on glucose metabolism in a mouse model of NASH/T2D, with a focus on its diuretic effects. To imitate ascites and to determine its severity by imaging, meglumine sodium amidotrizoate (MSA) was infused into the abdominal cavities of mice. The reduction in ascites induced by dapagliflozin was compared with that induced by furosemide using microcomputed tomography. The effects of each drug on hemodynamics were also compared. A dapagliflozin-related improvement in glucose tolerance was achieved in mice fed a high-fat diet (HFD) or an HFD + methionine-and-choline-deficient diet (MCDD). In dapagliflozin-treated NASH mice, hypoglycemia was not identified during 24-hour casual blood glucose monitoring. In the dapagliflozin and furosemide-treated groups, the time taken for the resolution of artificial ascites was significantly shorter than in the untreated group, and there were no significant differences between these groups. Furosemide significantly reduced the blood pressure and significantly increased the heart rate of the mice. Dapagliflozin caused a mild decrease in systolic, but not diastolic blood pressure, and the heart rate and circulating catecholamine and renin-aldosterone concentrations were unaffected. Dapagliflozin treatment improved glycemic control in the NASH mice versus untreated mice. Thus, dapagliflozin had a prompt diuretic effect but did not adversely affect the hemodynamics of mice with NASH and T2D. Therefore, it may be useful for the treatment of patients with both T2D and liver cirrhosis.

Blockade of sodium-glucose cotransporter 2 suppresses high glucose-induced angiotensinogen augmentation in renal proximal tubular cells

Renal proximal tubular angiotensinogen (AGT) is increased by hyperglycemia (HG) in diabetes mellitus, which augments intrarenal angiotensin II formation, contributing to the development of hypertension and kidney injury. Sodium-glucose cotransporter 2 (SGLT2) is abundantly expressed in proximal tubular cells (PTCs). The present study investigated the effects of canagliflozin (CANA), a SGLT2 inhibitor, on HG-induced AGT elevation in cultured PTCs. Mouse PTCs were treated with 5-25 mM glucose. CANA (0-10 µM) was applied 1 h before glucose treatment. Glucose (10 mM) increased AGT mRNA and protein levels at 12 h (3.06 ± 0.48-fold in protein), and 1 and 10 µM CANA as well as SGLT2 shRNA attenuated the AGT augmentation. CANA did not suppress the elevated AGT levels induced by 25 mM glucose. Increased AGT expression induced by treatment with pyruvate, a glucose metabolite that does not require SGLT2 for uptake, was not attenuated by CANA. In HG-treated PTCs, intracellular reactive oxygen species levels were elevated compared with baseline (4.24 ± 0.23-fold), and these were also inhibited by CANA. Furthermore, tempol, an antioxidant, attenuated AGT upregulation in HG-treated PTCs. HG-induced AGT upregulation was not inhibited by an angiotensin II receptor antagonist, indicating that HG stimulates AGT expression in an angiotensin II-independent manner. These results indicate that enhanced glucose entry via SGLT2 into PTCs elevates intracellular reactive oxygen species generation by stimulation of glycolysis and consequent AGT augmentation. SGLT2 blockade limits HG-induced AGT stimulation, thus reducing the development of kidney injury in diabetes mellitus.

A 96-week, multinational, randomized, double-blind, parallel-group, clinical trial evaluating the safety and effectiveness of bexagliflozin as a monotherapy for adults with type 2 diabetes

AIM

To explore the safety and effectiveness of extended exposure to bexagliflozin as a monotherapy for type 2 diabetes.

METHODS

Adults with diabetes (n = 288) from the USA, Colombia and Mexico were randomized 1:1 to receive bexagliflozin (20 mg) or placebo for 96 weeks. The primary endpoint was the placebo-adjusted change in HbA1c at 24 weeks. Dosing was continued an additional 72 weeks to assess safety and the durability of the treatment effect. Secondary endpoints measured changes from baseline in body mass and systolic blood pressure (SBP) and diastolic blood pressure (DBP) at week 24, and the change, over study duration, in HbA1c_. RESULTS: The placebo-adjusted change in HbA1c from baseline to week 24 was -0.79% (-8.6 mmol/mol) [95%CI -0.53, -1.06 (-5.8, -11.6), P < .0001]. The unadjusted change from baseline through week 96 was -0.55% (-6.0 mmol/mol) ± 1.184% (12.9) (SD) for the bexagliflozin arm compared with 0.53% (5.8 mmol/mol) ± 1.215% (13.3) for the placebo arm (P < .0001). Significant decreases in body mass, SBP and DBP could be attributed to bexagliflozin exposure. The incidence of serious adverse events was lower in the bexagliflozin-treated group (2.8%) than in the placebo group (8.5%). Urinary tract infections occurred less frequently in the active arm (14.5%) than in the placebo arm (20.6%).

CONCLUSIONS

Bexagliflozin at 20 mg/d was well tolerated and provided a durable, clinically meaningful improvement in glycaemic control over 96 weeks to participants in this phase 2 trial. A substantial reduction in weight and blood pressure was produced by bexagliflozin, with no increase in significant adverse event rates.

The SGLT2 Inhibitor Canagliflozin Prevents Carcinogenesis in a Mouse Model of Diabetes and Non-Alcoholic Steatohepatitis-Related Hepatocarcinogenesis: Association with SGLT2 Expression in Hepatocellular Carcinoma

The aim of the present study is to investigate the effects of canagliflozin, a selective sodium-glucose co-transporter 2 (SGLT2) inhibitor, on non-alcoholic steatohepatitis (NASH) and NASH-related hepatocellular carcinoma (HCC) in a mouse model of diabetes and NASH-HCC. First, mice aged five weeks were divided into two groups (vehicle group and canagliflozin group) and were treated for three weeks. Then, mice aged five weeks were divided into three groups of nine animals each: the vehicle group, early canagliflozin group (treated from five to nine weeks), and continuous canagliflozin group (treated from five to 16 weeks). Canagliflozin was administered at a dose of 30 mg/kg in these experiments. In addition, the in vitro effects of canagliflozin were investigated using HepG2 cells, a human HCC cell line. At the age of eight or 16 weeks, the histological non-alcoholic fatty liver disease activity score was lower in the canagliflozin-treated mice than in vehicle-treated mice. There were significantly fewer hepatic tumors in the continuous canagliflozin group than in the vehicle group. Immunohistochemistry showed significantly fewer glutamine synthetase-positive nodules in the continuous canagliflozin group than in the vehicle group. Expression of α-fetoprotein mRNA, a marker of HCC, was downregulated in the continuous canagliflozin group when compared with the vehicle group. At 16 weeks, there was diffuse SGLT1 expression in the hepatic lobules and strong expression by hepatocytes in the vehicle group, while SGLT2 expression was stronger in liver tumors than in the lobules. In the in vitro study, canagliflozin (10 μM) suppressed the proliferation of HepG2 cells. Flow cytometry showed that canagliflozin reduced the percentage of HepG2 cells in the G2/M phase due to arrest in the G1 phase along with decreased expression of cyclin D and Cdk4 proteins, while it increased the percentage of cells in the G0/1 phase. Canagliflozin also induced apoptosis of HepG2 cells via activation of caspase 3. In this mouse model of diabetes and NASH/HCC, canagliflozin showed anti-steatotic and anti-inflammatory effects that attenuated the development of NASH and prevented the progression of NASH to HCC, partly due to the induction of cell cycle arrest and/or apoptosis as well as the reduction of tumor growth through the direct inhibition of SGLT2 in tumor cells.

Cardiovascular and Renal Outcomes With Canagliflozin According to Baseline Kidney Function

Supplemental Digital Content is available in the text.

Background:

Canagliflozin is approved for glucose lowering in type 2 diabetes and confers cardiovascular and renal benefits. We sought to assess whether it had benefits in people with chronic kidney disease, including those with an estimated glomerular filtration rate (eGFR) between 30 and 45 mL/min/1.73 m² in whom the drug is not currently approved for use.

Methods:

The CANVAS Program randomized 10 142 participants with type 2 diabetes and eGFR >30 mL/min/1.73 m² to canagliflozin or placebo. The primary outcome was a composite of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke, with other cardiovascular, renal, and safety outcomes. This secondary analysis describes outcomes in participants with and without chronic kidney disease, defined as eGFR <60 and ≥60 mL/min/1.73 m², and according to baseline kidney function (eGFR <45, 45 to <60, 60 to <90, and ≥90 mL/min/1.73 m²).

Results:

At baseline, 2039 (20.1%) participants had an eGFR <60 mL/min/1.73 m², 71.6% of whom had a history of cardiovascular disease. The effect of canagliflozin on the primary outcome was similar in people with chronic kidney disease (hazard ratio, 0.70; 95% CI, 0.55–0.90) and those with preserved kidney function (hazard ratio, 0.92; 95% CI, 0.79–1.07; P heterogeneity = 0.08). Relative effects on most cardiovascular and renal outcomes were similar across eGFR subgroups, with possible heterogeneity suggested only for the outcome of fatal/nonfatal stroke (P heterogeneity = 0.01), as were results for almost all safety outcomes.

Conclusions:

The effects of canagliflozin on cardiovascular and renal outcomes were not modified by baseline level of kidney function in people with type 2 diabetes and a history or high risk of cardiovascular disease down to eGFR levels of 30 mL/min/1.73 m². Reassessing current limitations on the use of canagliflozin in chronic kidney disease may allow additional individuals to benefit from this therapy.

Clinical Trial Registration:

URL: https://www.clinicaltrials.gov. Unique identifiers: NCT01032629, NCT01989754.

The diabetes pandemic suggests unmet needs for 'CKD with diabetes' in addition to 'diabetic nephropathy'-implications for pre-clinical research and drug testing

Curing 'diabetic nephropathy' is considered an unmet medical need of high priority. We propose to question the concept of 'diabetic nephropathy' that implies diabetes as the predominant cause of kidney disease, which may not apply to the majority of type 2 diabetics approaching end-stage kidney disease. With the onset of diabetes, hyperglycaemia/sodium-glucose co-transporter-2-driven glomerular hyperfiltration promotes nephron hypertrophy, which, however, on its own, causes proteinuria not before a decade later, probably because podocyte hypertrophy can usually accommodate an increase in the filtration surface. In contrast, precedent chronic kidney disease (CKD), that is, few nephrons per body mass, e.g. due to poor nephron endowment from birth, obesity, pregnancy, or renal ageing or injury-related nephron loss, usually precedes the onset of type 2 diabetes. This applies in particular in older adults, and each on its own, but especially in combination, further aggravates single nephron hyperfiltration and glomerular hypertrophy. Whenever this additional hyperglycaemia-driven enlargement of the glomerular filtration surface exceeds the capacity of podocytes for hypertrophy, podocytes detachment leads to glomerulosclerosis and nephron loss, i.e. CKD progression. Animal models of 'diabetic nephropathy' based only on hyperglycaemia do not mimic this aspect and therefore poorly predict outcomes of clinical trials usually performed on elderly CKD patients with type 2 diabetes. Thus, we advocate the use of renal mass (nephron) ablation in type 2 diabetic animals to better mimic the pathophysiology of 'CKD with diabetes' in the target patient population and the use of the glomerular filtration rate as a primary endpoint to more reliably predict trial outcomes.

Weight loss variability with SGLT2 inhibitors and GLP-1 receptor agonists in type 2 diabetes mellitus and obesity: Mechanistic possibilities

We are facing a global epidemic of obesity and type 2 diabetes. Weight loss, in the context of obesity and type 2 diabetes, may improve glycaemic control and weight-related comorbidities, and in some cases, induce diabetes remission. Although lifestyle-based weight loss strategies may be initially successful, most are not effective long-term. There is an increasing need to consider pharmacological approaches to assist weight loss in diabetes-obesity. Older glucose-lowering agents may cause weight gain, whereas the newer drug classes, sodium-glucose co-transporter 2 inhibitors (SGLT2i) and glucagon-like peptide receptor agonists (GLP-1 RAs), concomitantly target weight loss and glycaemic control. Clinical trial data suggest that both SGLT2i and GLP1 RAs cause a mean weight loss of approximately 2 to 3 kg but real-world evidence and clinical experience suggests a significant heterogeneity in the magnitude of the weight loss (GLP-1 RAs) or the magnitude of the actual weight loss is significantly less than anticipated (SGLT2i). Why do some individuals lose more weight than others in response to these pharmacological treatments? This review will first explore mechanisms by which body weight is regulated through control of energy balance and its dysregulation in obesity, and then consider how these mechanisms may be modulated therapeutically with SGLT2i and GLP1 RAs.

Sodium-glucose cotransporter inhibitors: beyond glycaemic control

Diabetes increases the risk of adverse cardiovascular and renal events. Recently, sodium-glucose co-transporter 2 (SGLT2) inhibitors have been demonstrated to reduce cardiovascular complications and slow diabetic kidney disease progression in patients with type 2 diabetes. The glycaemic control exerted by these drugs is not greater than the one achieved with other classical glucose-lowering medications such as sulphonylureas. For that reason, plausible renoprotective mechanisms independent from glycaemic control have been proposed such as blood pressure control, body weight loss, intraglomerular pressure reduction and a decrease in urinary proximal tubular injury biomarkers. Interestingly, the hypothesis that SGLT2 inhibitors have a direct renoprotective effect has been addressed in diabetic and non-diabetic models. In this editorial, we update the different postulated mechanisms involved in the cardiorenal protection afforded by SGLT2 inhibition in chronic kidney disease.

Impact of sodium glucose cotransporter 2 inhibitor on histological features and glucose metabolism of non-alcoholic fatty liver disease complicated by diabetes mellitus

AIM

The aim of this study was to investigate the therapeutic potential of sodium glucose cotransporter 2 inhibitor (SGLT2I) as an effective therapeutic option for non-alcoholic fatty liver disease (NAFLD).

METHODS

In this prospective study, nine patients with NAFLD complicated by type 2 diabetes mellitus (DM), were introduced to the regimen of canagliflozin 100 mg once daily for 24 weeks and were evaluated by liver histology at pretreatment and at 24 weeks after the start of treatment. The primary outcome was histological improvement, defined as a decrease in NAFLD activity score of one point or more without worsening in fibrosis stage. Glucose metabolism was evaluated based on the meal tolerance test. The usefulness of extracellular and exosome microRNA-122 (miR-122) as early predictors of histological improvement was investigated.

RESULTS

All of the nine patients achieved histological improvement. Scores of steatosis, lobular inflammation, ballooning, and fibrosis stage decreased by 78%, 33%, 22%, and 33% at 24 weeks compared to the pretreatment, respectively. Six patients showed improvement in insulin resistance, and the other three patients showed partial improvement of insulin secretion function. Six patients, who showed a decrease in both extracellular and exosome miR-122 ratios (the ratio of miR-122 levels at 1 day after treatment to that at baseline), showed histological improvement. Furthermore, one patient, who showed a decrease in exosome miR-122 ratios regardless of the increase in extracellular miR-122 ratios, also showed decreases in NAFLD activity score and fibrosis stage.

CONCLUSION

A prospective study showed that SGLT2I for NAFLD complicated by DM improved histological features in connection with glucose metabolism. This trial was registered as clinical trial UMIN000018166.

Canagliflozin Inhibits Human Endothelial Cell Proliferation and Tube Formation

Recent clinical trials revealed that sodium-glucose co-transporter 2 (SGLT2) inhibitors significantly reduce cardiovascular events in type 2 diabetic patients, however, canagliflozin increased limb amputations, an effect not seen with other SGLT2 inhibitors. Since endothelial cell (EC) dysfunction promotes diabetes-associated vascular disease and limb ischemia, we hypothesized that canagliflozin, but not other SGLT2 inhibitors, impairs EC proliferation, migration, and angiogenesis. Treatment of human umbilical vein ECs (HUVECs) with clinically relevant concentrations of canagliflozin, but not empagliflozin or dapagliflozin, inhibited cell proliferation. In particular, 10 μM canagliflozin reduced EC proliferation by approximately 45%. The inhibition of EC growth by canagliflozin occurred in the absence of cell death and was associated with diminished DNA synthesis, cell cycle arrest, and a striking decrease in cyclin A expression. Restoration of cyclin A expression via adenoviral-mediated gene transfer partially rescued the proliferative response of HUVECs treated with canagliflozin. A high concentration of canagliflozin (50 μM) modestly inhibited HUVEC migration by 20%, but markedly attenuated their tube formation by 65% and EC sprouting from mouse aortas by 80%. A moderate 20% reduction in HUVEC migration was also observed with a high concentration of empagliflozin (50 μM), while neither empagliflozin nor dapagliflozin affected tube formation by HUVECs. The present study identified canagliflozin as a robust inhibitor of human EC proliferation and tube formation. The anti-proliferative action of canagliflozin occurs in the absence of cell death and is due, in part, to the blockade of cyclin A expression. Notably, these actions are not seen with empagliflozin or dapagliflozin. The ability of canagliflozin to exert these pleiotropic effects on ECs may contribute to the clinical actions of this drug.

Canagliflozin: A Review in Type 2 Diabetes

Canagliflozin (Invokana^®) is a sodium-glucose co-transporter-2 (SGLT2) inhibitor indicated in various countries worldwide for the once-daily oral treatment of type 2 diabetes (T2D). Canagliflozin lowers blood glucose levels independently of insulin, with the inhibition of SGLT2 reducing renal reabsorption of glucose and increasing excretion of glucose in the urine. In well-designed clinical trials, canagliflozin (as first-line monotherapy or add-on therapy to other antihyperglycaemic agents) improved glycaemic control in adults with T2D, including those of older age and/or at high cardiovascular (CV) risk, and also had beneficial effects on their bodyweight and blood pressure (BP). CV risk reduction, as well as possible renal benefits, were also seen with canagliflozin in T2D patients at high CV risk in the CANVAS Program, an integrated analysis of two large CV outcomes studies. Canagliflozin was generally well tolerated, had a low risk of hypoglycaemia and was most commonly associated with adverse events such as genital and urinary tract infections and increased urination, consistent with its mechanism of action. Although the amputation and fracture risk observed among recipients of the drug require further investigation, canagliflozin is an important option for T2D management in adults.

A review of the mechanism of action, metabolic profile and haemodynamic effects of sodium-glucose co-transporter-2 inhibitors

Inhibition of glucose transport in the kidney, to produce glucosuria and thus directly lower blood glucose seems a remarkably simple way to treat diabetes (type 1 or type 2). The development of sodium-glucose co-transporter-2 (SGLT2) inhibitors and their subsequent clinical development has on one hand shown this to be true, but at another level has helped reveal a complex web of interacting effects starting in the kidney and modulating multiple metabolic pathways in a variety of other organs. These underlie the now clear benefits of this class of drugs in the management of type 2 diabetes from glucose lowering, weight loss and blood pressure reduction through to the reductions in cardiovascular and renal complications observed in long-term outcomes trials. They also explain some of the adverse effects that have emerged, including the risk of diabetic ketoacidosis. This review describes the effects of SGLT2 inhibition in relation to this complex physiology, and shows how this can favourably alter the pathophysiology of type 2 diabetes.