Effects of SGLT2 inhibitor dapagliflozin in patients with type 2 diabetes on skeletal muscle cellular metabolism

Mechanisms and therapeutic opportunities in metabolic aberrations of diabetic wounds: a narrative review

Metabolic aberrations are fundamental to the complex pathophysiology and challenges associated with diabetic wound healing. These alterations, induced by the diabetic environment, trigger a cascade of events that disrupt the normal wound-healing process. Key factors in this metabolic alternation include chronic hyperglycemia, insulin resistance, and dysregulated lipid and amino acid metabolism. In this review, we summarize the underlying mechanisms driving these metabolic changes in diabetic wounds, while emphasizing the broad implications of these disturbances. Additionally, we discuss therapeutic approaches that target these metabolic anomalies and how their integration with existing wound-healing treatments may yield synergistic effects, offering promising avenues for innovative therapies.

Comparison of efficacy and safety of pioglitazone and SGLT2 inhibitors in treating Asian patients in MASLD associated with type 2 diabetes: A meta-analysis

OBJECTIVE

To comprehensively evaluate the therapeutic efficacy of pioglitazone and SGLT2 inhibitors (SGLT2i) in patients with MASLD and Type 2 Diabetes(T2DM).

METHODS

Electronic databases, including Web of Science, PubMed, the Cochrane Library, China National Knowledge Internet (CNKI), Wan-Fang Digital Database, and China Science and Technology Journal Database (VIP) were searched from inception to December 2024. Two reviewers independently assessed study eligibility, performed continuous data extraction， and independently evaluated bias risks. Liver ultrasonography, computed tomography (CT), and biochemical indices were utilized to determine the impact of treatment in both groups. Improvement in liver biomarkers and fibrosis as primary outcome indicators; Improvement in body composition, metabolic parameters, glucose parameters, and incidence of adverse effects as a secondary outcome indicator. For continuous variables, mean and standard deviation (SD) were extracted. RevMan 5.4 software was used to systematically analyze the literature, including heterogeneity testing, odds ratios (OR) calculation, and 95 % confidence intervals (CI) for each influencing factor.

RESULTS

Nine randomly controlled trials with 755 Asian participants were included. Our research showed that SGLT2i was more effective than pioglitazone in improving fibrosis-4 score (SMD 0.41 [95%CI 0.18,0.64] p = 0.005), visceral fat area (SMD 0.34 [95%CI 0.14,0.54] p = 0.0007), BMI (SMD 0.29 [95%CI 0.03,0.56] p = 0.03), and low-density lipoprotein levels (SMD 0.21 [95%CI 0.04,0.38] p = 0.01). In contrast, no statistically significant differences were observed in other outcomes.

CONCLUSIONS

Our study demonstrated that in patients with MASLD and T2DM, SGLT2i was more effective overall in improving liver fibrosis, blood lipids, liver fat, and body composition in the short term. These findings establish a theoretical basis for safe and rational drug use in clinical practice. Additionally, they may contribute to new insights into the pathogenesis of MASLD and type 2 diabetes and drug discovery and development efforts.

D-BHB supplementation before moderate-intensity exercise suppresses lipolysis and selectively blunts exercise-induced long-chain acylcarnitine increase in pilot study of patients with long-chain fatty acid oxidation disorders

Patients with long-chain fatty acid oxidation disorders (LC-FAOD) have impaired endogenous ketone production due to defects in the beta-oxidation pathway. We explored supplementation of exogenous D-beta-hydroxybutyrate (D-BHB) as an alternative source of energy in a randomized, double-blinded crossover pilot study. Participants ≥18 years of age with a diagnosis of LC-FAOD completed two moderate-intensity treadmill exercises following an oral supplementation of D-BHB salts or an isocaloric maltodextrin beverage. Five subjects (1 VLCADD, 2 CPT2D, 2 LCHADD), 60 % male, mean age = 33 years were enrolled. Mild to moderate GI symptoms were related to ingestion of D-BHB. Plasma D-BHB was increased after oral D-BHB compared to maltodextrin (p < .001) with an average concentration of 0.43 mM in the post-exercise period. During exercise, free fatty acids (p = .01), fold change in long-chain acylcarnitine species (LC-AC) (p ≤ .03) and systolic BP (p = .02) were lower after D-BHB compared to the maltodextrin beverage. D-BHB suppresses lipolysis and selectively blunts exercise-induced long-chain acylcarnitines. There were no differences between beverages in acetylcarnitine, blood glucose, creatine kinase, VO2, HR, RPE or respiratory exchange ratio. Consumption of the D-BHB beverage was safe and well-tolerated. Plasma D-BHB levels achieved mild ketosis and suppressed lipolysis and the associated rise in LC-AC, but fell short of stimulating the energetic effects that might have resulted in altered exercise parameters such as RER, or HR. In conclusion, our results provide a strong rationale for future studies aimed toward defining the optimal multiple-dose regimen of D-BHB per day that might improve exercise tolerance and understanding the long-term impact of treatment in LC-FAOD subjects.

Effects of antidiabetic agents on lipid metabolism of skeletal muscle: A narrative review

Metabolic syndrome-related diseases frequently involve disturbances in skeletal muscle lipid metabolism. The accumulation of lipid metabolites, lipid-induced mitochondrial stress in skeletal muscle cells, as well as the inflammation of adjacent adipose tissue, are associated with the development of insulin resistance and metabolic dysfunction. Consequently, when antidiabetic medications are used to treat various chronic conditions related to hyperglycaemia, the impact on skeletal muscle lipid metabolism should not be overlooked. However, current research has predominantly focused on muscle mass rather than skeletal muscle lipid metabolism and its interplay with glucose metabolism. In this review, we summarised the latest research on the effects of antidiabetic drugs and certain natural compounds with antidiabetic activity on skeletal muscle lipid metabolism, focusing on data from preclinical to clinical studies. Given the widespread use of antidiabetic drugs, a better understanding of their effects on skeletal muscle lipid metabolism merits further attention in future research.

SGLT2 Inhibitors: The First Endothelial-Protector for Diabetic Nephropathy

Sodium-glucose co-transporter type 2 inhibitors (SGLT2i) have emerged as a class of agents relevant for managing diabetic nephropathy and cardiopathy. In a previous report, we noticed that these drugs share, with other drugs with "nephroprotective" effects, the ability to reduce the glomerular filtration rate (GFR), thus suggesting the kidney hemodynamic effect as a proxy for optimal drug dosage. We also noticed that all known nephroprotective drugs exert cardioprotective functions, suggesting the possibility of activities not mediated by the kidney. Finally, we observe that nephroprotective drugs can be grouped according to their effects on hemoglobin levels, thus suggesting their mechanism of action. While the primary mechanism of SGLT2i involves glycosuria and natriuria, growing evidence suggests broader therapeutic effects beyond hemodynamic modulation. Specifically, the evidence that SGLT2 can be expressed in several atypical regions under pathological conditions, supports the possibility that its inhibition has several extratubular effects. Evidence supports the hypothesis that SGLT2i influence mitochondrial function in various cell types affected by diabetes, particularly in the context of diabetic nephropathy. Notably, in SGLT2i-treated patients, the extent of albumin-creatinine ratio (ACR) reduction post-treatment may be correlated with mitochondrial staining intensity in glomerular endothelial cells. This implies that the anti-proteinuric effects of SGLT2i could involve direct actions on glomerular endothelial cell. Our investigation into the role of SGLT2 inhibitors (SGLT2i) in endothelial function suggests that the aberrant expression of SGLT2 in endothelial cells in T2DM would lead to intracellular accumulation of glucose; therefore, SGLT2i are the first type of endothelial protective drugs available today, with potential implications for ageing-related kidney disease. The review reveals two major novel findings: SGLT2 inhibitors are the first known class of endothelial-protective drugs, due to their ability to prevent glucose accumulation in endothelial cells where SGLT2 is aberrantly expressed in Type 2 Diabetes. Additionally, the research demonstrates that SGLT2 inhibitors share a GFR-reducing effect with other nephroprotective drugs, suggesting both a mechanism for optimal drug dosing and potential broader applications in ageing-related kidney disease through their effects on mitochondrial function and glomerular endothelial cells.

Comprehensive treatment with dapagliflozin in elderly chronic kidney disease patients: Clinical efficacy and impact on body composition

BACKGROUND

Dapagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, is widely used for treating heart failure and chronic kidney disease (CKD). While its renoprotective effects are well established, concerns remain regarding its impact on muscle mass and function, especially in elderly patients.

OBJECTIVE

To assess the effects of dapagliflozin on renal function, body composition, and muscle strength in elderly CKD patients.

METHODS

Twelve elderly CKD patients (75.6 ± 1.4 years) were treated with dapagliflozin for 12 months. Body composition, serum parameters, and muscle function were evaluated at baseline, 6 months, and 12 months. Measurements included changes in eGFR, liver function, HbA1c, and muscle strength.

RESULTS

Dapagliflozin treatment stabilized eGFR without significant improvement, but proteinuria was notably reduced in most patients, indicating a positive renal effect. AST and ALT levels showed significant reduction after 12 months, suggesting improved liver function. No significant changes were observed in body weight, BMI, or muscle mass. Muscle function, as measured by the 5-sit-to-stand test, improved significantly, while grip strength remained stable. No serious adverse events were reported.

CONCLUSION

Dapagliflozin is a safe and effective treatment for CKD in elderly patients, demonstrating renal protection and improved liver function without adversely affecting muscle mass or strength. The study supports the use of dapagliflozin as part of a comprehensive approach, combining pharmacotherapy, lifestyle modification, and exercise to optimize patient outcomes in CKD management.

Comparative efficacy of GLP-1 RAs/SGLT-2 inhibitors in reducing cardiovascular events in type 2 diabetes according to baseline use of metformin: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Sodium-glucose transporters 2 inhibitors (SGLT-2i) and glucagon-like peptide 1 receptor agonists (GLP-1 RAs) are recommended along with metformin for the potential cardiovascular benefits among type 2 diabetes. This meta-analysis aims to evaluate whether the effects of SGLT-2i or GLP-1 RAs on cardiovascular outcomes are consistent with and without baseline metformin use.

METHODS

PubMed, Cochrane, Web of Science and Embase were searched for randomized placebo-controlled trials with SGLT-2i or GLP-1 RAs as interventions of type 2 diabetes patients up to June, 2024. The main outcomes were major adverse cardiovascular events (MACE), hospitalization for heart failure (HHF) or cardiovascular death. Both random-effects model and fixed model were adopted to estimate pooled hazard ratios (HR) and 95% confidence intervals (95% CI).

RESULTS

A total of 81,738 patients (median age: 62-66 years, 53.7-71.5% men, median follow-up: 1.3-5.4 years) from 11 studies (7 studies of SGLT-2i and 4 of GLP-1 RAs) were included in the study. The metformin-naive portions ranged from 28.90% to 81.98%. Among patients using metformin at baseline, SGLT-2i or GLP-1 RAs reduced MACE risk (HR = 0.95, 95% CI 0.91-0.99, P = 0.02). In metformin-naive patients, similar reductions were observed (HR = 0.79, 95% CI 0.65-0.95, P = 0.01). No statistically significant interaction was found between metformin users and non-users for any outcome (all P values for interaction > 0.05), indicating consistent cardiovascular benefits regardless of baseline metformin therapy.

CONCLUSIONS

SGLT-2i and GLP-1 RAs have the effects of cardiovascular benefits for T2DM patients regardless of baseline metformin use.

Deciphering the mechanisms and effects of hyperglycemia on skeletal muscle atrophy

Hyperglycemia, a hallmark of diabetes mellitus, significantly contributes to skeletal muscle atrophy, characterized by progressive muscle mass and strength loss. This review summarizes the mechanisms of hyperglycemia-induced muscle atrophy, examines clinical evidence, and discusses preventive and therapeutic strategies. A systematic search of electronic databases, including PubMed, Scopus, and Web of Science, was conducted to identify relevant papers on hyperglycemic skeletal muscle atrophy. Key mechanisms include insulin resistance, chronic inflammation, oxidative stress, and mitochondrial dysfunction. Crucial molecular pathways involved are Phosphoinositide 3-kinase/Protein kinase B signaling, Forkhead box O transcription factors, the ubiquitin-proteasome system, and myostatin-mediated degradation. Hyperglycemia disrupts normal glucose and lipid metabolism, exacerbating muscle protein degradation and impairing synthesis. Clinical studies support the association between hyperglycemia and muscle atrophy, emphasizing the need for early diagnosis and intervention. Biomarkers, imaging techniques, and functional tests are vital for detecting and monitoring muscle atrophy in hyperglycemic patients. Management strategies focus on glycemic control, pharmacological interventions targeting specific molecular pathways, nutritional support, and tailored exercise regimens. Despite these advances, research gaps remain in understanding the long-term impact of hyperglycemia on muscle health and identifying novel therapeutic targets. The review aims to provide a comprehensive understanding of the mechanisms, clinical implications, and potential therapeutic strategies for addressing hyperglycemia-induced skeletal muscle atrophy.

Molecular mechanisms of lipid droplets-mitochondria coupling in obesity and metabolic syndrome: insights and pharmacological implications

Abnormal lipid accumulation is a fundamental contributor to obesity and metabolic disorders. Lipid droplets (LDs) and mitochondria (MT) serve as organelle chaperones in lipid metabolism and energy balance. LDs play a crucial role in lipid storage and mobilization, working in conjunction with MT to regulate lipid metabolism within the liver, brown adipose tissue, and skeletal muscle, thereby maintaining metabolic homeostasis. The novelty of our review is the comprehensive description of LD and MT interaction mechanisms. We also focus on the current drugs that target this metabolism, which provide novel approaches for obesity and related metabolism disorder treatment.

Effects of ipragliflozin on skeletal muscle adiposity in patients with diabetes and metabolic dysfunction-associated steatotic liver disease

Objective Myosteatosis affects the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) and may be a potential therapeutic target. This study aimed to examine the effects of ipragliflozin on myosteatosis in patients with type 2 diabetes mellitus (T2D) and MASLD. Methods Patients were treated with ipragliflozin (IPR group) or a control (CTR group) for 72 weeks in a randomized trial. Changes in myosteatosis of the lumbar skeletal muscles were evaluated using computed tomography (CT). The response of myosteatosis to treatment and the baseline characteristics of the patients were analyzed. Patients 44 participants (IPR group, 23; CTR group, 21) with MASLD complicated by T2D Results Myosteatosis increased in the CTR group (n=23) but remained unchanged in the IPR group (n=21). The changes were apparent at 24 weeks (P=0.004), but were not significant after 24 weeks. A hierarchical cluster analysis was performed to identify clusters with and without improvement in myosteatosis. The clusters with decreasing intramuscular adipose tissue content (IMAC) at 48 and 72 weeks were not treated, but they had lower visceral fat area and severe liver steatosis at baseline. Improvements in glycemic control and resistance to decreasing abdominal skeletal muscle area from baseline to 24 weeks affected the decrease in IMAC at 48 and 72 weeks. Conclusion Ipragliflozin had a limited effect on skeletal muscle adiposity in patients with T2D and MASLD. Regardless of the treatment, a specific phenotype of adiposity and hepatic steatosis before treatment is associated with the long-term outcomes of myosteatosis. Maintaining skeletal muscle mass and better glycemic control during treatment are essential for the future improvement of myosteatosis.

Management of inflammaging in kidney diseases: focusing on the current investigational drugs

INTRODUCTION

To improve kidney disease treatments, it is crucial to understand how inflammaging affects patients´ longevity. We could potentially slow down kidney disease progression and enhance longevity by targeting specific pathways involved in inflammaging with potential drugs.

AREAS OF COVERED

This review offers an updated overview of 'anti-inflammaging' drugs currently in the kidney disease research pipeline, as well as those with potential for future therapeutic use. Furthermore, these drugs are categorized according to their mechanisms, including targeting inflammation, immune and metabolic regulation, oxidative stress, senescence, and autophagy, as demonstrated in preclinical and early clinical trials. Additionally, the review provides insights into key challenges and opinions for future advancements in this field.

EXPERT OPINION

We reviewed recent advancements in applying different therapies to mitigate inflammaging in kidney diseases. We underscore the need for continued research to elucidate the complex pathways underlying inflammaging, which will be essential for the development of more precise and effective treatments. As research in this field advances, several emerging drugs appear promising for future investigation. While current findings are encouraging, further clinical studies are required to validate the therapeutic potential of these agents in kidney diseases, ultimately paving the way for more targeted and efficacious interventions.

SGLT2 Inhibitor Dapagliflozin Increases Skeletal Muscle and Brain Fatty Acid Uptake in Individuals With Type 2 Diabetes: A Randomized Double-Blind Placebo-Controlled Positron Emission Tomography Study

OBJECTIVE

The aim of this study was to investigate the impact of the sodium-glucose cotransporter 2 (SGLT2) inhibitor dapagliflozin on tissue fatty acid (FA) uptake in the skeletal muscle, brain, small intestine, and subcutaneous and visceral adipose tissue of individuals with type 2 diabetes by using positron emission tomography (PET).

RESEARCH DESIGN AND METHODS

In a 6-week randomized double-blind placebo-controlled trial, 53 patients with type 2 diabetes treated with metformin received either 10 mg dapagliflozin or placebo daily. Tissue FA uptake was quantified at baseline and end of treatment with PET and the long-chain FA analog radiotracer 14(R,S)-[18F]fluoro-6-thia-heptadecanoic acid. Treatment effects were assessed using ANCOVA, and the results are reported as least square means and 95% CIs for the difference between groups.

RESULTS

A total of 38 patients (dapagliflozin n = 21; placebo n = 17) completed the study. After 6 weeks, skeletal muscle FA uptake was increased by dapagliflozin compared with placebo (1.0 [0.07, 2.0] μmol ⋅ 100 g-1 ⋅ min-1; P = 0.032), whereas uptake was not significantly changed in the small intestine or visceral or subcutaneous adipose tissue. Dapagliflozin treatment significantly increased whole-brain FA uptake (0.10 [0.02, 0.17] μmol ⋅ 100 g-1 ⋅ min-1; P = 0.01), an effect observed in both gray and white matter regions.

CONCLUSIONS

Six weeks of treatment with dapagliflozin increases skeletal muscle and brain FA uptake, partly driven by a rise in free FA availability. This finding is in accordance with previous indirect measurements showing enhanced FA metabolism in response to SGLT2 inhibition and extends the notion of a shift toward increased FA use to muscle and brain.

Dapagliflozin improves skeletal muscle insulin sensitivity through SIRT1 activation induced by nutrient deprivation state

Lipid peroxidation and mitochondrial damage impair insulin sensitivity in skeletal muscle. Sirtuin-1 (SIRT1) protects mitochondria and activates under energy restriction. Dapagliflozin (Dapa) is an antihyperglycaemic agent that belongs to the sodium-glucose cotransporter-2 (SGLT2) inhibitors. Evidence shows that Dapa can induce nutrient deprivation effects, providing additional metabolic benefits. This study investigates whether Dapa can trigger nutrient deprivation to activate SIRT1 and enhance insulin sensitivity in skeletal muscle. We treated diet-induced obese (DIO) mice with Dapa and measured metabolic parameters, lipid accumulation, oxidative stress, mitochondrial function, and glucose utilization in skeletal muscle. β-hydroxybutyric acid (β-HB) was intervened in C2C12 myotubes. The role of SIRT1 was verified by RNA interference. We found that Dapa treatment induced nutrient deprivation state and reduced lipid deposition and oxidative stress, improved mitochondrial function and glucose tolerance in skeletal muscle. The same positive effects were observed after β-HB intervening for C2C12 myotubes, and the promoting effects on glucose utilization were diminished by SIRT1 RNA interference. Thus, Dapa promotes a nutrient deprivation state and enhances skeletal muscle insulin sensitivity via SIRT1 activation. In this study, we identified a novel hypoglycemic mechanism of Dapa and the potential mechanistic targets.

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.

Impaired skeletal muscle regeneration in diabetes: From cellular and molecular mechanisms to novel treatments

Diabetes represents a major public health concern with a considerable impact on human life and healthcare expenditures. It is now well established that diabetes is characterized by a severe skeletal muscle pathology that limits functional capacity and quality of life. Increasing evidence indicates that diabetes is also one of the most prevalent disorders characterized by impaired skeletal muscle regeneration, yet underlying mechanisms and therapeutic treatments remain poorly established. In this review, we describe the cellular and molecular alterations currently known to occur during skeletal muscle regeneration in people with diabetes and animal models of diabetes, including its associated comorbidities, e.g., obesity, hyperinsulinemia, and insulin resistance. We describe the role of myogenic and non-myogenic cell types on muscle regeneration in conditions with or without diabetes. Therapies for skeletal muscle regeneration and gaps in our knowledge are also discussed, while proposing future directions for the field.

A 52-week efficacy and safety study of enavogliflozin versus dapagliflozin as an add-on to metformin in patients with type 2 diabetes mellitus: ENHANCE-M extension study

AIM

To evaluate the long-term safety and efficacy of enavogliflozin 0.3 mg/day added to metformin in patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

After 24 weeks of a randomized, double-blind treatment period with enavogliflozin 0.3 mg/day (n = 101) or dapagliflozin 10 mg/day (n = 99) added to metformin, all patients received enavogliflozin 0.3 mg/day plus metformin for an additional 28 weeks during the open-label extension period.

RESULTS

Eighty-two patients continued enavogliflozin (maintenance group), and 77 were switched from dapagliflozin to enavogliflozin (switch group). All adverse drug reactions (ADR) were mild in severity. In the maintenance group, ADRs (cystitis and vaginal infection) were reported in two patients (2.44%) during 52 weeks. In the switch group, ADR (hypoglycaemia) was reported in one patient (1.30%) during a 28-week open-label extension period. At week 52, glycated haemoglobin and fasting plasma glucose were significantly lower than at the baseline, by 0.85% and 29.08 mg/dl, respectively, in the maintenance group (p < .0001 for both), and by 0.81% and 32.77 mg/dl, respectively, in the switch group (p < .0001 for both). At week 52, 68.92% of patients from the maintenance group and 64.29% from the switch group achieved glycated haemoglobin <7%. A significant increase in the urine glucose-creatinine ratio was observed at week 52, by 58.81 g/g and 63.77 g/g in the maintenance and switch groups, respectively (p < .0001).

CONCLUSIONS

Enavogliflozin added to metformin was tolerated well for up to 52 weeks and provided continual glycaemic control in type 2 diabetes mellitus, along with a significant increase in the urine glucose-creatinine ratio.

Recent advances in understanding the mechanisms in skeletal muscle of interaction between exercise and frontline antihyperglycemic drugs

Regular exercise and antihyperglycemic drugs are front-line treatments for type-2 diabetes and related metabolic disorders. Leading drugs are metformin, sodium-glucose cotransporter-2 inhibitors, and glucagon-like peptide 1 receptor agonists. Each class has strong individual efficacy to treat hyperglycemia, yet the combination with exercise can yield varied results, some of which include blunting of expected metabolic benefits. Skeletal muscle insulin resistance contributes to the development of type-2 diabetes while improvements in skeletal muscle insulin signaling are among key adaptations to exercise training. The current review identifies recent advances into the mechanisms, with an emphasis on skeletal muscle, of the interaction between exercise and these common antihyperglycemic drugs. The review is written toward researchers and thus highlights specific gaps in knowledge and considerations for future study directions.

The antidiabetic SGLT2 inhibitor canagliflozin reduces mitochondrial metabolism in a model of skeletal muscle insulin resistance

AIMS

Sodium-glucose cotransporter 2 (SGLT2) inhibitors such as canagliflozin (CANA) have emerged as an effective adjuvant therapy in the management of diabetes, however, past observations suggest CANA may alter skeletal muscle mass and function. The purpose of this work was to investigate the effects of CANA on skeletal muscle metabolism both with and without insulin resistance.

METHODS

C2C12 myotubes were treated with CANA with or without insulin resistance. Western blot and qRT-PCR were used to assess protein and gene expression, respectively. Cell metabolism was assessed via oxygen consumption and extracellular acidification rate. Mitochondrial, nuclei and lipid content were measured using fluorescent staining and microscopy.

RESULTS

CANA decreased mitochondrial function and glycolytic metabolism as did insulin resistance, however, these changes occurred without significant alterations in gene expression associated with each pathway. Additionally, while insulin resistance reduced insulin-stimulated pAkt expression, CANA had no significant effect on insulin sensitivity.

CONCLUSIONS

CANA appears to reduce mitochondrial and glycolytic metabolism without altering gene expression governing these pathways, suggesting a reduction in substrate may be responsible for lower metabolism.

Cardiovascular benefits of SGLT2 inhibitors and GLP-1 receptor agonists through effects on mitochondrial function and oxidative stress

Overloaded glucose levels in several metabolic diseases such as type 2 diabetes (T2D) can lead to mitochondrial dysfunction and enhanced production of reactive oxygen species (ROS). Oxidative stress and altered mitochondrial homeostasis, particularly in the cardiovascular system, contribute to the development of chronic comorbidities of diabetes. Diabetes-associated hyperglycemia and dyslipidemia can directly damage vascular vessels and lead to coronary artery disease or stroke, and indirectly damage other organs and lead to kidney dysfunction, known as diabetic nephropathy. The new diabetes treatments include Na+-glucose cotransporter 2 inhibitors (iSGLT2) and glucagon-like 1 peptide receptor agonists (GLP-1RA), among others. The iSGLT2 are oral anti-diabetic drugs, whereas GLP-1RA are preferably administered through subcutaneous injection, even though GLP-1RA oral formulations have recently become available. Both therapies are known to improve both carbohydrate and lipid metabolism, as well as to improve cardiovascular and cardiorenal outcomes in diabetic patients. In this review, we present an overview of current knowledge on the relationship between oxidative stress, mitochondrial dysfunction, and cardiovascular therapeutic benefits of iSGLT2 and GLP-1RA. We explore the benefits, limits and common features of the treatments and remark how both are an interesting target in the prevention of obesity, T2D and cardiovascular diseases, and emphasize the lack of a complete understanding of the underlying mechanism of action.

Diabetes Pharmacotherapy and its effects on the Skeletal Muscle Energy Metabolism

The disorders of skeletal muscle metabolism in patients with Type 2 diabetes mellitus (T2DM), such as mitochondrial defection and glucose transporters (GLUTs) translocation dysfunctions, are not uncommon. Therefore, when anti-diabetic drugs were used in various chronic diseases associated with hyperglycemia, the impact on skeletal muscle should not be ignored. However, current studies mainly focus on muscle mass rather than metabolism or functions. Anti-diabetic drugs might have a harmful or beneficial impact on skeletal muscle. In this review, we summarize the upto- date studies on the effects of anti-diabetic drugs and some natural compounds on skeletal muscle metabolism, focusing primarily on emerging data from pre-clinical to clinical studies. Given the extensive use of anti-diabetic drugs and the common sarcopenia, a better understanding of energy metabolism in skeletal muscle deserves attention in future studies.

Efficacy and Safety of Enavogliflozin versus Dapagliflozin as Add-on to Metformin in Patients with Type 2 Diabetes Mellitus: A 24-Week, Double-Blind, Randomized Trial

BACKGRUOUND

Enavogliflozin is a novel sodium-glucose cotransporter-2 inhibitor currently under clinical development. This study evaluated the efficacy and safety of enavogliflozin as an add-on to metformin in Korean patients with type 2 diabetes mellitus (T2DM) against dapagliflozin.

METHODS

In this multicenter, double-blind, randomized, phase 3 study, 200 patients were randomized to receive enavogliflozin 0.3 mg/day (n=101) or dapagliflozin 10 mg/day (n=99) in addition to ongoing metformin therapy for 24 weeks. The primary objective of the study was to prove the non-inferiority of enavogliflozin to dapagliflozin in glycosylated hemoglobin (HbA1c) change at week 24 (non-inferiority margin of 0.35%) (Clinical trial registration number: NCT04634500).

RESULTS

Adjusted mean change of HbA1c at week 24 was -0.80% with enavogliflozin and -0.75% with dapagliflozin (difference, -0.04%; 95% confidence interval, -0.21% to 0.12%). Percentages of patients achieving HbA1c <7.0% were 61% and 62%, respectively. Adjusted mean change of fasting plasma glucose at week 24 was -32.53 and -29.14 mg/dL. An increase in urine glucose-creatinine ratio (60.48 vs. 44.94, P<0.0001) and decrease in homeostasis model assessment of insulin resistance (-1.85 vs. -1.31, P=0.0041) were significantly greater with enavogliflozin than dapagliflozin at week 24. Beneficial effects of enavogliflozin on body weight (-3.77 kg vs. -3.58 kg) and blood pressure (systolic/diastolic, -5.93/-5.41 mm Hg vs. -6.57/-4.26 mm Hg) were comparable with those of dapagliflozin, and both drugs were safe and well-tolerated.

CONCLUSION

Enavogliflozin added to metformin significantly improved glycemic control in patients with T2DM and was non-inferior to dapagliflozin 10 mg, suggesting enavogliflozin as a viable treatment option for patients with inadequate glycemic control on metformin alone.

Exercise mitigates Dapagliflozin-induced skeletal muscle atrophy in STZ-induced diabetic rats

BACKGROUND

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are commonly used in the management of type 2 diabetes mellitus (T2DM) and have been found to worsen the reduction of skeletal muscle mass in individuals with T2DM. This study aims to examine the potential of exercise in mitigating the skeletal muscle atrophy induced by SGLT2i treatment.

METHODS

A rat model of T2DM (40 male Sprague-Dawley rats; T2DM induced by a combination of high-fat diet and streptozotocin) was used to examine the effects of six-week treatment with Dapagliflozin (DAPA, SGLT2i) in combination with either aerobic exercise (AE) or resistance training (RT) on skeletal muscle. T2DM-eligible rats were randomized into the T2DM control group (CON, n = 6), DAPA treatment group (DAPA, n = 6), DAPA combined with aerobic exercise intervention group (DAPA + AE, n = 6), and DAPA combined with resistance training intervention group (DAPA + RT, n = 6). To assess the morphological changes in skeletal muscle, myosin ATPase and HE staining were performed. mRNA expression levels of Atrogin-1, MuRF1, and Myostatin were determined using quantitative PCR. Furthermore, protein expression levels of AKT, p70S6K, mTOR, FoXO1/3A, NF-κB, and MuRF1 were examined through western blotting.

RESULTS

Both the administration of DAPA alone and the combined exercise intervention with DAPA resulted in significant reductions in blood glucose levels and body weight in rats. However, DAPA alone administration led to a decrease in skeletal muscle mass, whereas RT significantly increased skeletal muscle mass and muscle fiber cross-sectional area. The DAPA + RT group exhibited notable increases in both total protein levels and phosphorylation levels of AKT and p70S6K in skeletal muscle. Moreover, the DAPA, DAPA + AE, and DAPA + RT groups demonstrated downregulation of protein expression (FoXO1/3A) and mRNA levels (Atrogin-1, MuRF1, and Myostatin) associated with muscle atrophy.

CONCLUSIONS

Our findings provide support for the notion that dapagliflozin may induce skeletal muscle atrophy through mechanisms unrelated to protein metabolism impairment in skeletal muscle, as it does not hinder protein metabolic pathways while reduces muscle atrophy-related genes. Additionally, our observations reveal that RT proves more effective than AE in enhancing skeletal muscle mass and muscle fiber cross-sectional area in rats with T2DM by stimulating protein anabolism within the skeletal muscle.

Empagliflozin reduces podocyte lipotoxicity in experimental Alport syndrome

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are anti-hyperglycemic agents that prevent glucose reabsorption in proximal tubular cells. SGLT2i improves renal outcomes in both diabetic and non-diabetic patients, indicating it may have beneficial effects beyond glycemic control. Here, we demonstrate that SGLT2i affects energy metabolism and podocyte lipotoxicity in experimental Alport syndrome (AS). In vitro, we found that the SGLT2 protein was expressed in human and mouse podocytes to a similar extent in tubular cells. Newly established immortalized podocytes from Col4a3 knockout mice (AS podocytes) accumulate lipid droplets along with increased apoptosis when compared to wild-type podocytes. Treatment with SGLT2i empagliflozin reduces lipid droplet accumulation and apoptosis in AS podocytes. Empagliflozin inhibits the utilization of glucose/pyruvate as a metabolic substrate in AS podocytes but not in AS tubular cells. In vivo, we demonstrate that empagliflozin reduces albuminuria and prolongs the survival of AS mice. Empagliflozin-treated AS mice show decreased serum blood urea nitrogen and creatinine levels in association with reduced triglyceride and cholesterol ester content in kidney cortices when compared to AS mice. Lipid accumulation in kidney cortices correlates with a decline in renal function. In summary, empagliflozin reduces podocyte lipotoxicity and improves kidney function in experimental AS in association with the energy substrates switch from glucose to fatty acids in podocytes.