Tofogliflozin decreases body fat mass and improves peripheral insulin resistance

Sodium-glucose co-transporter 2 inhibitors and Sarcopenia: A controversy that must be solved

Diabetes mellitus is a risk factor for muscle loss and sarcopenia. Sodium-glucose co-transporter 2 inhibitors (SGLT2i) or "gliflozins" are one of the newest anti-hyperglycemic drugs. They reduce blood glucose levels by inhibiting renal glucose reabsorption in the early proximal convoluted tubule. Various randomized trials showed that SGLT2i have cardio-protective and reno-protective action. SGLT2i also affect body composition. They usually decrease body fat percentage, visceral and subcutaneous adipose tissue. However, regarding the muscle mass, there are conflicting findings some studies showing detrimental effects and others showed neutral or beneficial effects. This issue is extremely important not only because of the wide use of SGLT2i around globe; but also skeletal muscle mass consumes large amounts of calories during exercise and is an important determinant of resting metabolic rate and skeletal muscle loss hinders energy consumption leading to obesity. In this systematic review, we extensively reviewed the experimental and clinical studies regarding the impact of SGLT2i on muscle mass and related metabolic alterations. Importantly, studies are heterogeneous and there is unmet need to highlight the alterations in muscle during SGLT2i use.

Current Nutritional and Pharmacological Approaches for Attenuating Sarcopenia

Sarcopenia is characterized by a gradual slowing of movement due to loss of muscle mass and quality, decreased power and strength, increased risk of injury from falls, and often weakness. This review will focus on recent research trends in nutritional and pharmacological approaches to controlling sarcopenia. Because nutritional studies in humans are fairly limited, this paper includes many results from nutritional studies in mammals. The combination of resistance training with supplements containing amino acids is the gold standard for preventing sarcopenia. Amino acid (HMB) supplementation alone has no significant effect on muscle strength or muscle mass in sarcopenia, but the combination of HMB and exercise (whole body vibration stimulation) is likely to be effective. Tea catechins, soy isoflavones, and ursolic acid are interesting candidates for reducing sarcopenia, but both more detailed basic research on this treatment and clinical studies in humans are needed. Vitamin D supplementation has been shown not to improve sarcopenia in elderly individuals who are not vitamin D-deficient. Myostatin inhibitory drugs have been tried in many neuromuscular diseases, but increases in muscle mass and strength are less likely to be expected. Validation of myostatin inhibitory antibodies in patients with sarcopenia has been positive, but excessive expectations are not warranted.

Sarcopenia as a Little-Recognized Comorbidity of Type II Diabetes Mellitus: A Review of the Diagnosis and Treatment

BACKGROUND

Type II diabetes mellitus (T2DM) is one of the most widespread metabolic diseases worldwide, with a significant impact on morbi-mortality. Sarcopenia has a high risk in this population (two times more risk) and a high impact at the functional level, especially in older adults. In addition, it poses enormous challenges in the diagnosis, prevention, and treatment of this disease concomitantly. The objective is to review the current knowledge on the state of muscle mass and the pathogenesis, diagnosis, and treatment of sarcopenia in people with T2DM.

METHODS

A bibliographic search was conducted in the PubMed-Medline databases for articles from 2015 with previously defined terms.

RESULTS

A loss of muscle mass in older diabetic patients who are malnourished or at risk of malnutrition has a proven negative impact on their autonomy and is closely related to the risk of sarcopenia as a high-impact disease, and also with frailty, as an associated multidimensional syndrome. Notably, we found that malnutrition and protein deficiency are often underdiagnosed in obese and overweight T2DM patients. Biochemical markers could help in the future with approaches to managing T2DM and sarcopenia concomitantly. The four essential elements which form the basis of care for patients with diabetes and sarcopenia are pharmacological treatment, nutrition management, regular physical exercise, and correct daily regime.

CONCLUSIONS

The increasing prevalence of sarcopenia among older patients with T2DM has significant negative impacts on quality of life and is a public health concern. Effective diagnosis and management require a multidisciplinary approach involving pharmacological treatment, nutrition, exercise, and correct daily regime, with future research needed to understand the underlying mechanisms and improve diagnostic and treatment strategies.

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.

Effects of Tofogliflozin and Anagliptin Alone or in Combination on Glucose Metabolism and Atherosclerosis-Related Markers in Patients with Type 2 Diabetes Mellitus

Purpose

In people with type 2 diabetes mellitus (T2DM), both glucose metabolism abnormalities and atherosclerosis risk are significant concerns. This study aims to investigate the effects of the sodium-glucose cotransporter 2 inhibitor tofogliflozin (TOFO) and the dipeptidyl peptidase-4 inhibitor anagliptin (ANA) on markers of glucose metabolism and atherosclerosis when administered individually or in combination.

Methods

Fifty T2DM patients were divided into two groups (receiving either TOFO or ANA monotherapy) and observed for 12 weeks (observation points: 0 and 12 weeks). The TOFO and ANA groups were then further treated with ANA and TOFO, respectively, and the patients were observed for an additional 36 weeks (observation points: 24 and 48 weeks). Therapeutic effects and various biomarkers were compared between the two groups at the observation points.

Results

Combination therapy led to significant improvements in HbA1c levels and atherosclerosis markers. Additionally, the TOFO pretreatment group exhibited significant reductions in sLOX-1 and IL-6 levels.

Conclusion

The increase in sLOX-1 and IL-6 levels, which indicates the response of scavenger receptors to oxidized low-density lipoproteins in people with T2DM, is mitigated following TOFO and ANA combination therapy. TOFO alone or in combination with ANA may be beneficial for preventing atherosclerosis development in people with T2DM, in addition to its effect on improving HbA1c levels.

The Neuronal and Non-Neuronal Pathways of Sodium-Glucose Cotransporter-2 Inhibitor on Body Weight-Loss and Insulin Resistance

With the emergence of sodium-glucose cotransporter 2 inhibitors (SGLT2i), the treatment of type 2 diabetes mellitus (T2DM) has achieved a new milestone, of which the insulin-independent mechanism could produce weight loss, improve insulin resistance (IR) and exert other protective effects. Besides the well-acknowledged biochemical processes, the dysregulated balance between sympathetic and parasympathetic activity may play a significant role in IR and obesity. Weight loss caused by SGLT-2i could be achieved via activating the liver-brain-adipose neural axis in adipocytes. We previously demonstrated that SGLT-2 are widely expressed in central nervous system (CNS) tissues, and SGLT-2i could inhibit central areas associated with autonomic control through unidentified pathways, indicating that the role of the central sympathetic inhibition of SGLT-2i on blood pressure and weight loss. However, the exact pathway of SGLT2i related to these effects and to what extent it depends on the neural system are not fully understood. The evidence of how SGLT-2i interacts with the nervous system is worth exploring. Therefore, in this review, we will illustrate the potential neurological processes by which SGLT2i improves IR in skeletal muscle, liver, adipose tissue, and other insulin-target organs via the CNS and sympathetic nervous system/parasympathetic nervous system (SNS/PNS).

Cardiorenal protection of SGLT2 inhibitors—Perspectives from metabolic reprogramming

Sodium-glucose co-transporter 2 (SGLT2) inhibitors, initially developed as a novel class of anti-hyperglycaemic drugs, have been shown to significantly improve metabolic indicators and protect the kidneys and heart of patients with or without type 2 diabetes mellitus. The possible mechanisms mediating these unexpected cardiorenal benefits are being extensively investigated because they cannot solely be attributed to improvements in glycaemic control. Notably, emerging data indicate that metabolic reprogramming is involved in the progression of cardiorenal metabolic diseases. SGLT2 inhibitors reprogram systemic metabolism to a fasting-like metabolic paradigm, involving the metabolic switch from carbohydrates to other energetic substrates and regulation of the related nutrient-sensing pathways, which might explain some of their cardiorenal protective effects. In this review, we will focus on the current understanding of cardiorenal protection by SGLT2 inhibitors, specifically its relevance to metabolic reprogramming.

Association between serum insulin levels and heart failure-related parameters in patients with type 2 diabetes and heart failure treated with canagliflozin: a post-hoc analysis of the randomized CANDLE trial

Background

Insulin resistance and hyperinsulinemia in patients with type 2 diabetes (T2D) are adversely associated with the development and worsening of heart failure (HF). Herein, we sought to investigate the effect of canagliflozin on insulin concentrations and the associations of changes in insulin concentrations with HF-related clinical parameters in patients with T2D and HF.

Methods

This was a post-hoc analysis of the investigator-initiated, multicenter, open-label, randomized, controlled CANDLE trial for patients with T2D and chronic HF (UMIN000017669). The endpoints were the effects of 24 weeks of canagliflozin treatment, relative to glimepiride treatment, on insulin concentrations and the relationship between changes in insulin concentrations and clinical parameters of interest, including New York Heart Association (NYHA) classification. The effects of canagliflozin on those parameters were also analyzed by baseline insulin level.

Results

Among the participants in the CANDLE trial, a total of 129 patients (canagliflozin, n = 64; glimepiride, n = 65) who were non-insulin users with available serum insulin data both at baseline and week 24 were included in this analysis. Overall, the mean age was 69.0 ± 9.4 years; 75% were male; the mean HbA1c was 6.8 ± 0.7%; and the mean left ventricular ejection fraction was 59.0 ± 14.1%, with parameters roughly balanced between treatment groups. Canagliflozin treatment significantly reduced insulin concentrations at week 24 (p < 0.001), and the between-group difference (canagliflozin minus glimepiride) in those changes was − 3.52 mU/L (95% confidence interval, − 4.85 to − 2.19; p < 0.001). Decreases in insulin concentrations, irrespective of baseline insulin level, were significantly associated with improvement in NYHA class in patients treated with canagliflozin.

Conclusion

Our findings suggest that canagliflozin treatment in patients with T2D and HF ameliorated excess insulin overload, contributing to the improvement of clinical HF status.

Trial registration: University Medical Information Network Clinical Trial Registry, number 000017669, Registered on May 25, 2015.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01589-3.

The sodium-glucose cotransporter 2 inhibitor ipragliflozin improves liver function and insulin resistance in Japanese patients with type 2 diabetes

Sodium–glucose cotransporter 2 inhibitor (SGLT2i) treatment is a therapeutic approach for type 2 diabetes mellitus (T2DM). Some reports have shown that SGLT2i treatment improves insulin resistance; however, few studies have evaluated insulin resistance by the glucose clamp method. Hepatic insulin clearance (HIC) is a new pathophysiological mechanism of T2DM. The effect of SGLT2i treatment on hepatic insulin clearance and insulin resistance is not well known. We investigated the effect of SGLT2i treatment on insulin resistance, insulin secretion, incretin levels, body composition, and hepatic insulin clearance. We conducted a meal tolerance test (MTT) and a hyperinsulinemic-euglycemic clamp test in 9 T2DM patients. Ipragliflozin (50 mg/day) was administered, and the MTT and clamp test were performed after 4 months. We calculated HIC as the postprandial C-peptide AUC-to-insulin AUC ratio. We also measured GLP-1, GIP, and glucagon levels during the MTT. Body weight and HbA1c were decreased, although not significantly, after 4 months of treatment. Postprandial glucose, fasting insulin and postprandial insulin were significantly decreased. Insulin resistance with the glucose clamp was not changed, but the HOMA-IR and insulin sensitivity indices were significantly improved. Incretin and glucagon levels were not changed. Hepatic insulin clearance was significantly increased, but whole-body insulin clearance was not changed. The FIB-4 index and fatty liver index were significantly reduced. The HOMA-beta and insulinogenic indices were not changed, but the C-peptide index was significantly increased. Although the number of patients was small, these results suggested that SGLT2i treatment improved liver function, decreased hepatic insulin resistance, and increased hepatic insulin clearance, despite the small weight reduction.

Short-Term SGLT2 Inhibitor Administration Does Not Alter Systemic Insulin Clearance in Type 2 Diabetes

Background: Decreased insulin clearance could be a relatively upstream abnormality in obesity, metabolic syndrome, and nonalcoholic fatty liver disease. Previous studies have shown that sodium-glucose cotransporter 2 inhibitor (SGLT2i) increases insulin–C-peptide ratio, a marker of insulin clearance, and improves metabolic parameters. We evaluated the effects of the SGLT2i tofogliflozin on metabolic clearance rate of insulin (MCRI) with a hyperinsulinemic euglycemic clamp study, the gold standard for measuring systemic insulin clearance. Methods: Study participants were 12 Japanese men with type 2 diabetes. We evaluated MCRI and tissue-specific insulin sensitivity with a hyperinsulinemic euglycemic clamp (insulin infusion rate, 40 mU/m²·min) before and immediately after a single dose (n = 12) and 8 weeks (n = 9) of tofogliflozin. We also measured ectopic fat in muscle and liver and the abdominal fat area using ¹H-magnetic resonance spectroscopy and magnetic resonance imaging, respectively, before and after 8 weeks of tofogliflozin. Results: MCRI did not change after a single dose of tofogliflozin (594.7 ± 67.7 mL/min·m² and 608.3 ± 90.9 mL/min·m², p = 0.61) or after 8 weeks (582.5 ± 67.3 mL/min·m² and 602.3 ± 67.0 mL/min·m², p = 0.41). The 8-week treatment significantly improved glycated hemoglobin and decreased body weight (1.7%) and the subcutaneous fat area (6.4%), whereas insulin sensitivity and ectopic fat in muscle and liver did not change significantly. Conclusions: MCRI did not change after a single dose or 8 weeks of tofogliflozin. Increased MCRI does not precede a decrease in body fat or improved glycemic control.

The Impact of Glucose-Lowering Drugs on Sarcopenia in Type 2 Diabetes: Current Evidence and Underlying Mechanisms

The age-related decrease in skeletal muscle mass together with the loss of muscle power and function is defined sarcopenia. Mounting evidence suggests that the prevalence of sarcopenia is higher in patients with type 2 diabetes mellitus (T2DM), and different mechanisms may be responsible for this association such as impaired insulin sensitivity, chronic hyperglycemia, advanced glycosylation end products, subclinical inflammation, microvascular and macrovascular complications. Glucose-lowering drugs prescribed for patients with T2DM might impact on these mechanisms leading to harmful or beneficial effect on skeletal muscle. Importantly, beyond their glucose-lowering effects, glucose-lowering drugs may affect per se the equilibrium between protein anabolism and catabolism through several mechanisms involved in skeletal muscle physiology, contributing to sarcopenia. The aim of this narrative review is to provide an update on the effects of glucose-lowering drugs on sarcopenia in individuals with T2DM, focusing on the parameters used to define sarcopenia: muscle strength (evaluated by handgrip strength), muscle quantity/quality (evaluated by appendicular lean mass or skeletal muscle mass and their indexes), and physical performance (evaluated by gait speed or short physical performance battery). Furthermore, we also describe the plausible mechanisms by which glucose-lowering drugs may impact on sarcopenia.

Different Indicators of Adiposity and Fat Distribution and Cardiometabolic Risk Factors in Patients with Type 2 Diabetes

OBJECTIVE

This study aimed to evaluate the effect of adiposity and fat distribution on the odds of elevated cardiovascular risk factors among adults with type 2 diabetes mellitus.

METHODS

The present cross-sectional study included 2,427 adults with type 2 diabetes mellitus. Body fat was assessed by dual-energy x-ray absorptiometry. Multivariate-adjusted logistic regression was used to estimate effects of adiposity parameters on elevated hemoglobin A_1c (HbA_1c , ≥7.0%), hypertension (blood pressure ≥140/90 mmHg), and elevated low-density lipoprotein (LDL) cholesterol (≥2.6 mmol/L).

RESULTS

The multivariable-adjusted odds ratio (OR) for elevated HbA_1c was 0.82 (95% CI: 0.70-0.96) for each SD increase in leg fat mass. The multivariable-adjusted OR for hypertension was 1.15 (95% CI: 1.00-1.32) for each SD increase in android fat mass. Multivariable-adjusted ORs for elevated LDL cholesterol ranged from 1.16 (95% CI: 1.00-1.35) to 1.27 (95% CI: 1.06-1.51) for each SD increase in arm and android fat mass and percentage of total, truncal, arm, and android fat. Each SD increase in BMI, truncal-to-leg fat ratio, and android-to-gynoid fat ratio was significantly associated with increased risks of elevated HbA_1c , hypertension, and elevated LDL cholesterol.

CONCLUSIONS

Subcutaneous fat in the lower body was associated with a more favorable glycemic profile, but not blood pressure or lipid profile, whereas central adiposity was associated with poor control of cardiovascular risk factors among patients with type 2 diabetes mellitus.

Obesity and aging: Molecular mechanisms and therapeutic approaches

The epidemic of obesity is a major challenge for health policymakers due to its far-reaching effects on population health and potentially overwhelming financial burden on healthcare systems. Obesity is associated with an increased risk of developing acute and chronic diseases, including hypertension, stroke, myocardial infarction, cardiovascular disease, diabetes, and cancer. Interestingly, the metabolic dysregulation associated with obesity is similar to that observed in normal aging, and substantial evidence suggests the potential of obesity to accelerate aging. Therefore, understanding the mechanism of fat tissue dysfunction in obesity could provide insights into the processes that contribute to the metabolic dysfunction associated with the aging process. Here, we review the molecular and cellular mechanisms underlying both obesity and aging, and how obesity and aging can predispose individuals to chronic health complications. The potential of lifestyle and pharmacological interventions to counter obesity and obesity-related pathologies, as well as aging, is also addressed.

Rationale and design of the EMPA-ELDERLY trial: a randomised, double-blind, placebo-controlled, 52-week clinical trial of the efficacy and safety of the sodium-glucose cotransporter-2 inhibitor empagliflozin in elderly Japanese patients with type 2 diabetes

INTRODUCTION

Elderly people (≥65 years) with type 2 diabetes mellitus (T2DM) are becoming increasingly prevalent, notably in Japan. As cardiovascular (CV) risk increases with age and sodium-glucose cotransporter-2 (SGLT2) inhibitors reduce CV risk, elderly patients with T2DM are increasingly likely to be prescribed these glucose-lowering drugs. There is controversy surrounding the effects of SGLT2 inhibitors on muscle mass, particularly in elderly patients for whom loss of muscle is especially undesirable; however, robust evidence on this important issue is lacking. Consequently, we have designed a clinical trial of the SGLT2 inhibitor empagliflozin in elderly Japanese patients with T2DM (Empagliflozin in Elderly T2DM Patients (EMPA-ELDERLY)) to assess its effects on body composition as well as glycaemic control. EMPA-ELDERLY will be the first randomised clinical trial of an SGLT2 inhibitor in elderly patients with T2DM to evaluate effects on skeletal muscle mass, muscle strength and physical performance concurrently.

METHODS AND ANALYSIS

EMPA-ELDERLY is a randomised, double-blind, placebo-controlled, parallel-group clinical trial to be conducted in Japan. Patients with T2DM aged ≥65 years are eligible if they are Japanese with a body mass index of ≥22 kg/m² and glycated haemoglobin (HbA1c) levels from ≥7.0% to ≤10.0% from either diet and exercise alone or treatment with oral glucose-lowering drugs. Approximately 128 participants will be randomised 1:1 to once per day, oral, double-blind treatment with empagliflozin 10 mg or matching placebo for 52 weeks. The primary endpoint is the change in HbA1c level from baseline at week 52. Secondary endpoints include changes from baseline to 52 weeks in body composition, including muscle mass and body fat, measured by bioelectrical impedance analysis, as well as skeletal muscle index, grip strength and time in the five-time chair stand test. Other endpoints include changes in patient-reported outcomes (including quality of life), cognitive function and safety.

ETHICS AND DISSEMINATION

We will submit the trial results to conferences and peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04531462.

Insulin resistance and heart failure during treatment with sodium glucose cotransporter 2 inhibitors: proposed role of ketone utilization

Sodium glucose cotransporter 2 (SGLT2) inhibitors reduce the rate of hospitalization for heart failure in individuals with type 2 diabetes, but the underlying mechanisms remain elusive. Modestly elevated circulating β-hydroxybutyrate (βOHB) during treatment with SGLT2 inhibitors causes different beneficial effects on organs and cells, depending on succinyl-CoA:3-ketoacid CoA transferase (SCOT) levels. In the heart, in which SCOT is highly expressed/up-regulated, βOHB may be an alternative energy source apart from fat and glucose oxidation. The type 2 diabetic failing heart may be energy inefficient. In skeletal muscle, in which SCOT is not highly expressed/down-regulated, βOHB may cause antioxidant effects, resulting in amelioration of insulin resistance, which could lead to improvement in cardiac insulin resistance with metabolic, endocrine, and cytokine alterations. Although various mechanisms have been suggested, we postulate that the potential impact of SGLT2 inhibitors on heart failure lies in fuel energetics and amelioration of insulin resistance with ketone utilization depending upon SCOT levels.

Type 2 diabetes subgroups and potential medication strategies in relation to effects on insulin resistance and beta-cell function: A step toward personalised diabetes treatment?

Background

Type 2 diabetes is a syndrome defined by hyperglycaemia that is the result of various degrees of pancreatic β-cell failure and reduced insulin sensitivity. Although diabetes can be caused by multiple metabolic dysfunctions, most patients are defined as having either type 1 or type 2 diabetes. Recently, Ahlqvist and colleagues proposed a new method of classifying patients with adult-onset diabetes, considering the heterogenous metabolic phenotype of the disease. This new classification system could be useful for more personalised treatment based on the underlying metabolic disruption of the disease, although to date no prospective intervention studies have generated data to support such a claim.

Scope of Review

In this review, we first provide a short overview of the phenotype and pathogenesis of type 2 diabetes and discuss the current and new classification systems. We then review the effects of different anti-diabetic medication classes on insulin sensitivity and β-cell function and discuss future treatment strategies based on the subgroups proposed by Ahlqvist et al.

Major Conclusions

The proposed novel type 2 diabetes subgroups provide an interesting concept that could lead to a better understanding of the pathophysiology of the broad group of type 2 diabetes, paving the way for personalised treatment choices based on understanding the root cause of the disease. We conclude that the novel subgroups of adult-onset diabetes would benefit from anti-diabetic medications that take into account the main pathophysiology of the disease and thereby prevent end-organ damage. However, we are only beginning to address the personalised treatment of type 2 diabetes, and studies investigating the effects of current and novel drugs in subgroups with different metabolic phenotypes are needed to develop personalised treatment of the syndrome

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Novel subgroups of type 2 diabetes provide a concept that could lead to a better understanding of its pathophysiology.

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Treatment strategies would benefit from anti-diabetic medications that influence the main pathophysiology of diabetes.

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Here, we review different anti-diabetic medications classes affecting insulin sensitivity and β-cell function.

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We suggest that future treatment strategies could benefit by taking into account subgroups provided by Ahlqvist et al.

Comparison of tofogliflozin versus glimepiride as the third oral agent added to metformin plus a dipeptidyl peptidase-4 inhibitor in Japanese patients with type 2 diabetes: A randomized, 24-week, open-label, controlled trial (STOP-OB)

Metformin plus a dipeptidyl peptidase-4 inhibitor (DPP-4i) is the most common therapy for Japanese patients with type 2 diabetes. This 24-week, multicentre, open-label, parallel-group trial randomized patients on dual therapy to add-on tofogliflozin (20 mg/day, n = 33) or glimepiride (0.5 mg/day, n = 31). The primary outcome was change in body fat percentage. The secondary outcomes included changes in HbA1c, fat mass, fat-free mass, liver function variables and uric acid. Tofogliflozin and glimepiride reduced HbA1c to a similar extent. Body fat percentage did not change from baseline in either group. Fat mass was reduced by tofogliflozin but was increased by glimepiride (by -2.0 ± 1.7 kg and +1.6 ± 1.6 kg, P = .002). Fat-free mass was also reduced by tofogliflozin and increased by glimepiride (by -1.3 ± 1.3 kg and +0.9 ± 2.0 kg, P < .001). Alanine aminotransferase and uric acid levels were reduced by tofogliflozin (P = .006 and P < .001, respectively). These data provide novel information useful for selecting the third oral agent for patients whose diabetes is inadequately controlled with metformin plus DPP-4i dual therapy.

Improvement of skeletal muscle insulin sensitivity by 1 week of SGLT2 inhibitor use

BACKGROUND AND AIMS

It is currently unclear whether sodium-glucose co-transporter 2 (SGLT2) inhibitor administration can improve the insulin sensitivity as well as rapidly reduce plasma glucose concentrations in humans during the early phase of treatment initiation. This study aimed to investigate the effect of SGLT2 inhibitor on insulin sensitivity in the early phase of treatment initiation.

METHODS AND RESULTS

This single-center, open label, and single-arm prospective study recruited 20 patients (14 men) with type 2 diabetes mellitus (T2DM). We examined the patients' metabolic parameters before and 1 week after SGLT2 inhibitor (10 mg/day of empagliflozin) administration. The glucose infusion rate (GIR) was evaluated using the euglycemic hyperinsulinemic glucose clamp technique. Changes in laboratory and anthropometric parameters before and after SGLT2 inhibitor administration were analyzed according to the change in the GIR. The BMI, body fat amount, skeletal muscle amount, systolic blood pressure, and triglyceride level significantly decreased along with the treatment, while urinary glucose level and log GIR value significantly increased. Notably, changes in the GIR after SGLT2 inhibitor administration, which indicated improvement in peripheral insulin sensitivity, were negatively correlated with T2DM duration and positively with reduction in fluctuation of daily plasma glucose profiles before and after treatment.

CONCLUSION

SGLT2 inhibitor improved insulin sensitivity in the skeletal muscle independent of anthropometric changes. Patients with short duration of T2DM and insulin resistance can be good candidates for short-term SGLT2 inhibitor administration to improve insulin sensitivity in the skeletal muscle.

Sodium-Glucose Cotransporter 2 Inhibitors and Kidney Outcomes: True Renoprotection, Loss of Muscle Mass or Both?

Inhibitors of sodium-glucose cotransporter 2 (SGLT2) have emerged as practice-changing treatments for patients with type 2 diabetes, reducing both the risk of cardiovascular events and kidney events. However, regarding the latter, caution is warranted, as these kidney endpoints are defined using glomerular filtration rate estimations based on creatinine, the non-enzymatic product of creatine residing in muscles. Creatinine-based estimations of the glomerular filtration rate are only valid if the treatment has no effect on changes in muscle mass over time. Yet, circumstantial evidence suggests that treatment with SGLT2 inhibitors does result in a loss of muscle mass, rendering serum creatinine-based kidney endpoints invalid. Currently, it cannot be excluded that the described renoprotective effect of SGLT2 inhibitors is in part or in whole the consequence of a loss of muscle mass. Post-hoc analyses of existing trials or new trials based on kidney function markers independent of muscle mass can provide more definitive answers on the proposed renoprotective effects of SGLT2 inhibitors.

Canagliflozin ameliorates obesity by improving mitochondrial function and fatty acid oxidation via PPARα in vivo and in vitro

AIMS

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have been reported to significantly reduce body weight. This study investigated whether SGLT2 inhibitors directly affect adipose tissues and the underlying mechanisms in vivo and in vitro.

MAIN METHODS

Male C57BL/6 mice were fed a normal diet, high-fat diet (HFD), or HFD with canagliflozin for 14 weeks. 3T3-L1 adipocytes were treated with canagliflozin. Metabolic parameters were measured.

KEY FINDINGS

Canagliflozin reduced body weight, fat mass, and white adipose tissue (WAT) weight and inhibited adipocyte hypertrophy. Canagliflozin improved glucose and lipid metabolic disorders induced by HFD. Furthermore, canagliflozin treatment reversed the suppressed mRNA and protein expression of PGC-1α, NRF1, tfam and CPT1b, which are markers of mitochondrial biogenesis, function and fatty acid oxidation in mice with obesity. In vitro, canagliflozin increased mitochondrial DNA to nuclear DNA and upregulated the expression of PGC-1α, NRF1, tfam, COX5b, COX8b, Atp5o, and CPT1b mRNA and PGC-1α, NRF1, tfam, COX5b, CPT1b protein in 3T3-L1 adipocytes in a dose-dependent manner, while these increases were inhibited by GW6471, a PPARα antagonist.

SIGNIFICANCE

Our study showed that canagliflozin protected against HFD-induced obesity and obesity-related metabolic disorders by improving mitochondrial function and fatty acid oxidation in adipose tissue and adipocytes. Such energy-dissipating effects of canagliflozin may be mediated by PPARα.

Omarigliptin decreases inflammation and insulin resistance in a pleiotropic manner in patients with type 2 diabetes

BACKGROUND

Omarigliptin is a potent, selective, oral dipeptidyl peptidase 4 (DPP4) inhibitor with a half-life that allows weekly dosing. Inflammation or insulin resistance might be pathological mediators of cardiovascular events in patients with type 2 diabetes.

METHODS

Whether omarigliptin has anti-inflammatory effects that result in decreased levels of high-sensitivity C-reactive protein (hsCRP) and anti-insulin resistance effects that decrease levels of homeostatic model assessment of insulin resistance (HOMA-IR) were investigated. Patients were allocated to continue with daily DPP4 inhibitors (control, n = 28) or to switch from daily DPP4 inhibitors to weekly omarigliptin (omarigliptin, n = 56). Fasting blood and urine samples were collected before, and every 3 months after intervention for 1 year.

RESULTS

Omarigliptin tended to elicit reductions in fasting blood glucose (FBG), LDL-cholesterol, triglyceride, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transpeptidase (γ-GTP), the urinary albumin-to-creatinine ratio (ACR) with logarithmic transformation (log ACR), and systolic and diastolic blood pressure, but the differences did not reach statistical significance compared with control. Values for HDL-cholesterol tended to increase, but also did not reach statistical significance compared with control. Omarigliptin significantly decreased HOMA-IR, remnant-like particle cholesterol (RLP-C), and hsCRP with logarithmic transformation (log hsCRP) compared with control. However, omarigliptin did not affect hemoglobin A1c (HbA1c), body mass index (BMI), and estimated glomerular filtration rates (eGFR).

CONCLUSION

Omarigliptin decreased inflammation and insulin resistance without affecting HbA1c or BMI. Although how DPP4 inhibitors affect cardiovascular (CV) outcomes remains uncertain, omarigliptin might confer CV benefits at least in part, via pleiotropic anti-inflammatory or anti-insulin resistance effects.Trial registration UMIN Clinical Registry (UMIN000029288). Registered 22 September, 2017, https://upload.umin.ac.jp/UMIN000029288.

A Review of the Effects of Glucagon-Like Peptide-1 Receptor Agonists and Sodium-Glucose Cotransporter 2 Inhibitors on Lean Body Mass in Humans

Weight loss is an important goal in the management of several chronic conditions, including type 2 diabetes mellitus, and pharmacological therapies that aid weight loss are appealing. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter 2 inhibitors (SGLT2is) are novel glucose-lowering therapies that have been shown to induce clinically significant reductions in body weight. However, this weight loss may not be attributed solely to fat mass (FM). Given the importance of skeletal muscle and lean body mass (LBM) on cardio-metabolic health and physical function, we reviewed the available literature reporting the effects of GLP-1RAs and SGLT2is on body composition. Results demonstrate that, in most circumstances, the weight loss associated with both therapies predominantly comprises a reduction in FM, although significant heterogeneity exists between studies. In over half of the studies identified, the proportion of LBM reduction ranged between 20% and 50% of total weight lost, which is consistent with diet-induced weight loss and bariatric surgery. No clear differences existed between GLP-1RAs and SGLT2is. Consequently, the loss of LBM and skeletal muscle associated with weight loss induced by GLP-1RAs and SGLT2is warrants attention. Strategies to preserve skeletal muscle and improve physical function, for example through structured exercise, are of great importance.

Attenuation of Weight Loss Through Improved Antilipolytic Effect in Adipose Tissue Via the SGLT2 Inhibitor Tofogliflozin

CONTEXT

Although calorie loss from increased urinary glucose excretion continues after long-term treatment with sodium-glucose cotransporter 2 inhibitors (SGLT2is), the mechanisms of the attenuated weight loss due to SGLT2is are not well known.

OBJECTIVE

To examine the mechanism of the attenuated weight loss during long-term treatment with an SGLT2i, tofogliflozin, focusing on the antilipolytic effect of insulin on adipose tissue.

DESIGN AND PARTICIPANTS

An integrated analysis was performed using data from two phase 3 studies of 52 weeks of tofogliflozin administration. The antilipolytic effect was evaluated using adipose tissue insulin resistance (Adipo-IR) calculated from the product of the levels of fasting insulin (f-IRI) and fasting free fatty acids (f-FFAs).

RESULTS

Data from 774 patients with type 2 diabetes (mean age, 58.5 years; glycosylated hemoglobin, 8.1%; body mass index, 25.6 kg/m2; estimated glomerular filtration rate, 83.9 mL/min/1.73m2; 66% men) were analyzed. Weight loss plateaued between weeks 24 and 52 after decreasing significantly. f-IRI levels decreased significantly from baseline to week 24, and the decrease was maintained until Week 52. f-FFA levels significantly increased, peaked at week 24, then declined from weeks 24 to 52. Adipo-IR levels declined progressively throughout the 52 weeks (-3.6 mmol/L·pmol/L and -6.2 mmol/L·pmol/L at weeks 24 and 52, respectively; P < 0.001 baseline vs weeks 24 and 52 and week 24 vs week 52). Higher baseline Adipo-IR levels were independently associated with greater weight loss at week 52.

CONCLUSION

The improved antilipolytic effect in adipose tissue may attenuate progressive lipolysis, leading to attenuating future weight loss induced by an SGLT2i in patients with type 2 diabetes.

Natural products with SGLT2 inhibitory activity: Possibilities of application for the treatment of diabetes

Diabetes mellitus currently affects as many as 400 million people worldwide, creating a heavy economic burden and stretching health care resources. A dysfunction of glucose homeostasis underlies the disease. Despite advances in the treatment of diabetes, many patients still suffer from complications and side effects; hence, development of more effective treatments for diabetes is still desirable. SGLT2 is the principle cotransporter involved in glucose reabsorption in the kidney. SGLT2 inhibition reduces glucose reabsorption by the kidney and ameliorates plasma glucose concentration. The interest in natural products that can be used for the inhibition of SGLT2 is growing. The flavonoid phlorizin, which can be isolated from the bark of apple trees, has been used as lead structure due to its inhibitory activity of SGLT1 and SGLT2. Some phlorizin-derived synthetic compounds, including canagliflozin, dapagliflozin, empagliflozin, ipragliflozin, and ertugliflozin, are approved by the food and drug administration to treat type 2 diabetes mellitus (T2DM), whereas others are under clinical trials investigation. In addition, other natural product-derived compounds have been investigated for their ability to improve blood glucose control. The present review summarizes the natural products with SGLT2 inhibitory activity, and the synthetic compounds obtained from them, and discusses their application for the treatment of diabetes.

Body composition changes in diabetes and aging

Aging is associated with changes in body composition, including both fat gain and muscle loss beginning in middle age, and is associated with increased risk of type 2 diabetes. Moreover, changes in fat distribution take place in adults as they age and may contribute to the increased risk of type 2 diabetes. Recent literature has shown differences in the age-related changes in body composition by diabetes status suggesting that some of these changes might not only be a risk factor of the development of diabetes but could also be a consequence of the disease. In this article, we review the current evidence on body composition changes that take place in adults after the diagnosis of type 2 diabetes and compare them to those observed in adults without diabetes as they age. We also review the effect of various lifestyle, pharmacological, and surgical treatments that lower blood glucose on body composition in adults with type 2 diabetes.

Effect of canagliflozin on the overall clinical state including insulin resistance in Japanese patients with type 2 diabetes mellitus

AIMS

Information on the clinical efficacy of SGLT2 inhibitors in the Japanese population is limited. The aim of this single-arm, single-center, open-label study was to confirm the body weight- and fat mass-lowering effects of canagliflozin (CANA) and the accompanying improvement in insulin resistance in Japanese patients with Type 2 diabetes mellitus (T2DM).

METHODS

Thirty-eight patients were enrolled and administered 100 mg CANA once daily for 24 weeks. Blood and anthropometric parameters were examined before and after treatment. In a subset of patients, insulin sensitivity was assessed based on the glucose infusion rate (GIR) during a hyperinsulinemic euglycemic clamp test.

RESULTS

CANA treatment significantly decreased hemoglobin A1c, fasting plasma glucose, and plasma liver enzyme levels, and increased plasma adiponectin levels. In addition, a significant reduction in body weight, visceral and subcutaneous fat area, fat and lean mass, and liver steatosis was also observed. The change in plasma adiponectin levels significantly correlated with the changes in both body fat mass and visceral fat area. GIR increased from 3.25 ± 1.53 to 4.11 ± 1.30 mg/kg/min (P < 0.05).

CONCLUSIONS

CANA improved insulin resistance and decreased visceral fat mass in Japanese patients with T2DM.

Beneficial effects of SGLT2 inhibitors on fatty liver in type 2 diabetes: A common comorbidity associated with severe complications

Patients with type 2 diabetes mellitus (T2DM) are exposed to non-alcoholic fatty liver disease (NAFLD), a comorbidity associated with cardiovascular disease and chronic kidney disease, and which may progress to non-alcoholic steatohepatitis (NASH), fibrosis and cirrhosis. Sodium-glucose cotransporter type-2 (SGLT2) inhibitors are glucose-lowering agents that improve glucose control while promoting weight loss and lowering serum uric acid levels. These agents may exert cardiovascular and renal protection in T2DM patients with established cardiovascular disease. Recent findings from both randomized controlled trials and open-label studies have also shown that SGLT2 inhibitors are able to reduce fatty liver content, as assessed by different imaging techniques, and improve biological markers of NAFLD, especially serum liver enzymes, in patients with T2DM. In addition, there are emerging data to suggest a mechanism beyond the reduction of hyperglycaemia and body weight, and a potential role for the decrease in low-grade inflammation and oxidative stress associated with SGLT2 inhibitor therapy. This positive effect of SGLT2 inhibitors on NAFLD complements their already well-known effects on cardiovascular and chronic kidney diseases.

Rationale and Design of the STOP-OB Study for Evaluating the Effects of Tofogliflozin and Glimepiride on Fat Deposition in Type 2 Diabetes Patients Treated with Metformin/DPP-4 Inhibitor Dual Therapy

BACKGROUND

The global pandemic of type 2 diabetes mellitus (T2DM) is an enormous clinical and socioeconomic burden. Biguanides and DPP-4 inhibitors (DPP-4i) are the most commonly used therapies in Japanese T2DM patients. When glycemic control is not adequate despite combination of these drugs, there is no consensus on the next step drug. Systematic reviews and meta-analyses of previous trials have indicated that glycemic control with triple combination therapies yields similar results. Thus, beneficial effects on cardiovascular risk factors may be important. The present study was designed to evaluate body fat percentage and several insulin resistance parameters after addition of tofogliflozin or glimepiride to the regimens of patients being treated with metformin and a DPP-4 inhibitor but failing to attain adequate blood glucose control.

METHODS

Sodium glucose cotransporter-2 inhibitor, tofogliflozin versus glimepiride, comparative trial in patients with type 2 diabetes on body composition is an ongoing, multicenter, prospective, randomized, open-label, parallel-group trial. T2DM patients treated with metformin/DPP-4 inhibitor dual therapy have been recruited and randomly assigned to 20 mg/day tofogliflozin (n = 32) or 0.5 mg/day glimepiride (n = 32) groups, with either of these drugs being added to pre-existing regimens for 24 weeks.

PLANNED OUTCOMES

The primary endpoint is the change in body fat percentage from baseline to 24 weeks. The secondary outcomes are changes in body composition other than fat percentage, body weight, parameters related to glycemic control and β-cell function, parameters related to lipids and arteriosclerosis, parameters related to liver function, parameters related to diabetic nephropathy, and uric acid levels. Safety parameters will also be analyzed. This is the first trial comparing the effects and safety of adding an SGLT2i and a sulfonylurea as the third-line oral agent to metformin/DPP-4i dual therapy. The results will provide valuable information for choosing third-line oral agents.

TRIAL REGISTRATION

UMIN000026161.

FUNDING

Kowa Co. Ltd. and Kowa Pharmaceutical Co. Ltd., Tokyo, Japan.

Tofogliflozin decreases body fat mass and improves peripheral insulin resistance

The impact of tofogliflozin, a sodium-glucose co-transporter-2 inhibitor, on peripheral glucose uptake in patients with type 2 diabetes mellitus (T2DM) was investigated using the hyperinsulinaemic-euglycaemic clamp method in a single-arm, open-label study. The following variables were compared between before and after tofogliflozin administration for 12 weeks in 16 patients with T2DM who were receiving dipeptidyl peptidase-4 inhibitor treatment: body weight (BW); blood pressure; glucose metabolism; liver function; lipid profile; and body composition. Peripheral glucose uptake (M value and M/I ratio) was examined by the hyperinsulinaemic-euglycaemic clamp method. After 12 weeks, there was a significant decrease (P < .001) in glycated haemoglobin, BW, body fat mass and lean body mass. Peripheral glucose uptake, which indicates insulin sensitivity, increased significantly (M value by 0.90 and M/I ratio by 0.49; both P < .05). The change in the M value after 12 weeks of tofogliflozin therapy was correlated with the change in body fat mass (P < .05). Tofogliflozin significantly improved insulin sensitivity and peripheral glucose uptake in patients with T2DM. These improvements were significantly correlated with reduction in body fat mass.

Anti-inflammatory effects of empagliflozin in patients with type 2 diabetes and insulin resistance

BACKGROUND

Inflammation might be a pathological mediator of cardiovascular events in patients with type 2 diabetes and high cardiovascular risk.

METHODS

We investigated whether empagliflozin (EMPA) exerts anti-inflammatory effects that are reflected in decreased high-sensitivity C-reactive protein (hsCRP) values. Patients were allocated to receive a placebo (n = 51) or EMPA (n = 51) as an add-on treatment. Fasting blood samples were collected before and every 3 months after this intervention for 1 year.

RESULTS

Empagliflozin tended to elicit reductions in BMI, HbA1c, aspartate aminotransferase, alanine aminotransferase (ALT), and gamma-glutamyl transpeptidase compared with the placebo, but the differences did not reach statistical significance. Levels of LDL-cholesterol, HDL-cholesterol, and triglycerides were unaltered, significantly increased, and decreased, respectively, by EMPA, but the differences were not statistically significant compared with the placebo. Empagliflozin for 12 months notably reduced the homeostatic model assessment of insulin resistance (HOMA-IR), remnant-like particle cholesterol (RLP-C), and hsCRP by 43%, 52% and 54%, respectively. The time courses of these reductions significantly differed from those of the placebo. Systolic and diastolic blood pressure were also significantly reduced by EMPA compared with the placebo. We applied multiple linear regression analysis to determine which factors were associated with changes in hsCRP induced by EMPA. The results revealed that alterations in hsCRP values (log [hsCRP at 12 months] minus log [hsCRP at month 0]) were significantly associated with changes in HOMA-IR, RLP-C, systolic blood pressure, HDL-C and ALT.

CONCLUSION

Empagliflozin decreased hs-CRP and lowered levels of remnant related lipoproteins probably via ameliorating insulin resistance. The cardiovascular benefits conferred by EMPA might be driven at least partly by anti-inflammatory effects, and this mechanism might cooperate with other EMPA-induced changes including reduced blood pressure, to achieve the degree of cardioprotection revealed by the EMPA-REG OUTCOME trial.Trial registration UMIN Clinical Registry (UMIN000021552). Registered 21 March 2016, https://upload.umin.ac.jp/UMIN000021552.