Antidiabetic effects of SGLT2-selective inhibitor ipragliflozin in streptozotocin-nicotinamide-induced mildly diabetic mice

SGLT2 inhibitor and loop diuretic induce different vasopressin and fluid homeostatic responses in nondiabetic rats

Loop diuretics are commonly used diuretics in the treatment of fluid retention but induce hypovolemia-related renal dysfunction. Na+-glucose cotransporter 2 (SGLT2) inhibitors induce osmotic diuresis, but body fluid volume is maintained by stimulating vasopressin-induced fluid intake and collecting duct water reabsorption as previously reported in diabetic rats. We aimed to test the hypothesis that unlike SGLT2 inhibitors, loop diuretics lack activation of similar fluid homeostatic mechanisms. Nondiabetic male Sprague-Dawley rats were treated daily by oral gavage with vehicle, the SGLT2 inhibitor ipragliflozin (5 mg/kg), or the loop diuretic furosemide (50 mg/kg) and monitored in metabolic cages for 2 or 7 days. Ipragliflozin and furosemide similarly increased urine volume on day 2. This was associated with increased serum Na+ concentration, urine vasopressin excretion, fluid intake, and solute-free water reabsorption in response to ipragliflozin but not to furosemide. Ipragliflozin maintained fluid balance (fluid intake - urine volume) on day 2 and total body water measured by bioimpedance spectroscopy and serum creatinine on day 7. In comparison, furosemide decreased fluid balance on day 2 and decreased total body water and increased serum creatinine on day 7. Furosemide, but not ipragliflozin, increased plasma renin activity, and systolic blood pressure was similar among the groups. In conclusion, the osmotic diuresis of the SGLT2 inhibitor increased serum Na+ concentration and the vasopressin-related stimulation of fluid intake and renal water retention maintained fluid balance, whereas the loop diuretic did not engage the compensatory vasopressin system. The data suggest differences in vasopressin and fluid homeostatic responses between SGLT2 inhibitors and loop diuretics.NEW & NOTEWORTHY In nondiabetic rats, the Na+-glucose cotransporter 2 (SGLT2) inhibitor ipragliflozin increased vasopressin-related stimulation of fluid intake and free water reabsorption and maintained fluid balance and serum creatinine, whereas the loop diuretic furosemide reduced vasopressin and induced a negative fluid balance followed by a subsequent increase in serum creatinine. This study suggests that differences in vasopressin secretion in response to a SGLT2 inhibitor or loop diuretic may contribute to differences in body fluid status and subsequent renal function.

Ipragliflozin attenuates non-alcoholic steatohepatitis development in an animal model

Non-alcoholic steatohepatitis (NASH) is a common chronic liver disease with no decisive treatment. The sodium glucose cotransporter 2 (SGLT2) inhibitor ipragliflozin was developed as a new oral hypoglycemic drug, which can improve NASH via an insulin-independent glucose-lowering effect by inhibiting glucose reabsorption in the renal proximal tubules. However, ipragliflozin appears to modulate steatosis or inflammation via different pathways. To elucidate the new mechanism of ipragliflozin for the treatment of NASH, we evaluated its effects in a NASH mouse model (STAM mice) with beta cell depletion, and compared the expression of microRNAs (miRNAs) in STAM mice treated with or without ipragliflozin (16.7 μg/day for 5 weeks). Ipragliflozin reduced aspartate transaminase and alanine aminotransferase levels, along with reduced hepatic steatosis, hepatocyte ballooning, lobular inflammation, and liver fibrosis. In addition, ipragliflozin upregulated mitochondrial transport-related and antioxidant defensive system-related genes in the liver. Among 2555 mouse miRNA probes, miR-19b-3p was commonly differentially expressed with ipragliflozin treatment for 5 weeks in both the liver and serum but in different directions, with a decrease in the liver and increase in the serum. Therefore, ipragliflozin can improve NASH development likely through the antioxidative stress pathway and by regulating miR-19b-3p.

Peripheral combination treatment of leptin and an SGLT2 inhibitor improved glucose metabolism in insulin-dependent diabetes mellitus mice

We investigated whether peripheral combination treatment of a sodium-glucose cotransporter 2 (SGLT2) inhibitor and leptin improves glucose metabolism in insulin-dependent diabetes mellitus (IDDM) model mice. Twelve-week-old male C57BL6 mice were intraperitoneally administered a high dose of streptozotocin to produce IDDM. IDDM mice were then divided into five groups: SGLT2 inhibitor treatment alone, leptin treatment alone, leptin and SGLT2 inhibitor co-treatment, untreated IDDM mice, and healthy mice groups. The blood glucose (BG) level at the end of the dark cycle was measured, and a glucose tolerance test (GTT) was performed and compared between the five groups. Leptin was peripherally administered at 20 μg/day using an osmotic pump, and an SGLT2 inhibitor, ipragliflozin, was orally administered at 3 mg/kg/day. Monotherapy with SGLT2 inhibitor or leptin significantly improved glucose metabolism in mice as evaluated by BG and GTT compared with the untreated group, whereas the co-treatment group with SGLT2 inhibitor and leptin further improved glucose metabolism as compared with the monotherapy group. Notably, glucose metabolism in the co-treatment group improved to the same level as that in the healthy mice group. Thus, peripheral combination treatment with leptin and SGLT2 inhibitor improved glucose metabolism in IDDM mice without the use of insulin.

Ipragliflozin, an SGLT2 Inhibitor, Ameliorates High-Fat Diet-Induced Metabolic Changes by Upregulating Energy Expenditure through Activation of the AMPK/ SIRT1 Pathway

BACKGROUND

Sodium-glucose co-transporter 2 (SGLT2) inhibitors are a new class of antidiabetic drugs that exhibit multiple extraglycemic effects. However, there are conflicting results regarding the effects of SGLT2 inhibition on energy expenditure and thermogenesis. Therefore, we investigated the effect of ipragliflozin (a selective SGLT2 inhibitor) on energy metabolism.

METHODS

Six-week-old male 129S6/Sv mice with a high propensity for adipose tissue browning were randomly assigned to three groups: normal chow control, 60% high-fat diet (HFD)-fed control, and 60% HFD-fed ipragliflozin-treated groups. The administration of diet and medication was continued for 16 weeks.

RESULTS

The HFD-fed mice became obese and developed hepatic steatosis and adipose tissue hypertrophy, but their random glucose levels were within the normal ranges; these features are similar to the metabolic features of a prediabetic condition. Ipragliflozin treatment markedly attenuated HFD-induced hepatic steatosis and reduced the size of hypertrophied adipocytes to that of smaller adipocytes. In the ipragliflozin treatment group, uncoupling protein 1 (Ucp1) and other thermogenesis-related genes were significantly upregulated in the visceral and subcutaneous adipose tissue, and fatty acid oxidation was increased in the brown adipose tissue. These effects were associated with a significant reduction in the insulin-to-glucagon ratio and the activation of the AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1) pathway in the liver and adipose tissue.

CONCLUSION

SGLT2 inhibition by ipragliflozin showed beneficial metabolic effects in 129S6/Sv mice with HFD-induced obesity that mimics prediabetic conditions. Our data suggest that SGLT2 inhibitors, through their upregulation of energy expenditure, may have therapeutic potential in prediabetic obesity.

Osmotic diuresis by SGLT2 inhibition stimulates vasopressin-induced water reabsorption to maintain body fluid volume

Most of the filtered glucose is reabsorbed in the early proximal tubule by the sodium-glucose cotransporter SGLT2. The glycosuric effect of the SGLT2 inhibitor ipragliflozin is linked to a diuretic and natriuretic effect that activates compensatory increases in fluid and food intake to stabilize body fluid volume (BFV). However, the compensatory mechanisms that are activated on the level of renal tubules remain unclear. Type 2 diabetic Goto-Kakizaki (GK) rats were treated with vehicle or 0.01% (in diet) ipragliflozin with free access to fluid and food. After 8 weeks, GK rats were placed in metabolic cages for 24-hr. Ipragliflozin decreased body weight, serum glucose and systolic blood pressure, and increased fluid and food intake, urinary glucose and Na+ excretion, urine volume, and renal osmolar clearance, as well as urine vasopressin and solute-free water reabsorption (TcH2O). BFV, measured by bioimpedance spectroscopy, and fluid balance were similar among the two groups. Urine vasopressin in ipragliflozin-treated rats was negatively and positively associated with fluid balance and TcH2O, respectively. Ipragliflozin increased the renal membrane protein expression of SGLT2, aquaporin (AQP) 2 phosphorylated at Ser269 and vasopressin V2 receptor. The expression of SGLT1, GLUT2, AQP1, and AQP2 was similar between the groups. In conclusion, the SGLT2 inhibitor ipragliflozin induced a sustained glucosuria, diuresis, and natriuresis, with compensatory increases in fluid intake and vasopressin-induced TcH2O in proportion to the reduced fluid balance to maintain BFV. These results indicate that the osmotic diuresis induced by SGLT2 inhibition stimulates compensatory fluid intake and renal water reabsorption to maintain BFV.

Solid-State Quantification of Cocrystals in Pharmaceutical Tablets Using Transmission Low-Frequency Raman Spectroscopy

To enable the continuous production of cocrystal-containing pharmaceutical tablets, guaranteeing the cocrystal content of the final pharmaceutical tablets in the solid state is critical. This study demonstrates the quantification of caffeine-glutaric acid cocrystals in model tablets using transmission low-frequency Raman spectroscopy. Although distinguishing between cocrystals and raw materials using conventional Raman spectroscopy is difficult, the use of low-frequency Raman spectroscopy enables the discrimination of cocrystals and raw materials. Low-frequency Raman spectra were analyzed by the partial least-squares method (PLS) to obtain the predicted contents in the model tablets. To evaluate the quantitative ability of this method, the root means square error of cross-validation (RMSECV) was determined by comparing the actual concentration and predicted content with a calibration curve. For cocrystal-containing tablets, the quantitative ability of the transmission mode (RMSECV = 2.06- 3.17) was 13.4-31.4% higher than that of the backscattering mode (RMSECV= 2.37- 3.91). The coexistence of raw crystalline materials did not affect the quantitative ability for cocrystals.

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

AIMS

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

MAIN METHODS

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

KEY FINDINGS

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

SIGNIFICANCE

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

Effects of unaltered and bioconverted mulberry leaf extracts on cellular glucose uptake and antidiabetic action in animals

Background

Mulberry is a Korean medicinal herb that shows effective prevention and treatment of obesity and diabetes. Bioconversion is the process of producing active ingredients from natural products using microorganisms or enzymes.

Methods

In this study, we prepared bioconverted mulberry leaf extract (BMLE) with Viscozyme L, which we tested in insulin-sensitive cells (i.e., skeletal muscle cells and adipocytes) and insulin-secreting pancreatic β-cells, as well as obese diabetic mice induced by co-administration of streptozotocin (100 mg/kg, IP) and nicotinamide (240 mg/kg, IP) and feeding high-fat diet, as compared to unaltered mulberry leaf extract (MLE).

Results

BMLE increased the glucose uptake in C2C12 myotubes and 3 T3-L1 adipocytes and increased glucose-stimulated insulin secretion in HIT-T15 pancreatic β-cells. The fasting blood glucose levels in diabetic mice treated with BMLE or MLE (300 and 600 mg/kg, PO, 7 weeks) were significantly lower than those of the vehicle-treated group. At the same concentration, BMLE-treated mice showed better glucose tolerance than MLE-treated mice. Moreover, the blood concentration of glycated hemoglobin (HbA_1C) in mice treated with BMLE was lower than that in the MLE group at the same concentration. Plasma insulin levels in mice treated with BMLE or MLE tended to increase compared to the vehicle-treated group. Treatment with BMLE yielded significant improvements in insulin resistance and insulin sensitivity.

Conclusion

These results indicate that in the management of diabetic condition, BMLE is superior to unaltered MLE due to at least, in part, high concentrations of maker compounds (trans-caffeic acid and syringaldehyde) in BMLE.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2460-5) contains supplementary material, which is available to authorized users.

Protective Effect of Ipragliflozin on Pancreatic Islet Cells in Obese Type 2 Diabetic db/db Mice

Ipragliflozin is a selective sodium glucose cotransporter 2 (SGLT2) inhibitor that increases urinary glucose excretion and subsequently improves hyperglycemia in patients with type 2 diabetes mellitus (T2DM). To assess the beneficial effect of ipragliflozin on the mass and function of pancreatic β-cells under diabetic conditions, obese T2DM db/db mice were treated with ipragliflozin for 5 weeks. Glucose and lipid metabolism parameters, pathological changes in pancreatic islet cells and insulin content were evaluated. Pathological examination of pancreatic islet cells comprised measuring the ratios of insulin- and glucagon-positive cells and levels of oxidative stress markers. Hemoglobin A1c, plasma glucose, non-esterified fatty acid and triglyceride levels in ipragliflozin-treated groups were reduced compared to the diabetic control (DM-control) group. Histopathological examination of pancreatic islet cells revealed strong insulin staining and reduced glucagon staining in the ipragliflozin 10 mg/kg-treated group compared with the DM-control group. The ratio of α- to β-cell mass was lower in the ipragliflozin 10 mg/kg-treated group than the DM-control group and was similar to that of the non-diabetic control group. The density of immunostaining for 4-hydroxy-2-nonenal, an oxidative stress marker, in pancreatic islets was significantly lower in the ipragliflozin 10 mg/kg-treated group than the DM-control group. Pancreatic insulin content tended to be higher in the ipragliflozin-treated groups than the DM-control group. Our findings demonstrate the benefit of ipragliflozin treatment in improving glucolipotoxicity and reducing oxidative stress in pancreatic islet cells. Treatment with ipragliflozin may protect against the progressive loss of islet β-cells in patients with T2DM.

Unmasking a sustained negative effect of SGLT2 inhibition on body fluid volume in the rat

The chronic intrinsic diuretic and natriuretic tone of sodium-glucose cotransporter 2 (SGLT2) inhibitors is incompletely understood because their effect on body fluid volume (BFV) has not been fully evaluated and because they often increase food and fluid intake at the same time. Here we first compared the effect of the SGLT2 inhibitor ipragliflozin (Ipra, 0.01% in diet for 8 wk) and vehicle (Veh) in Spontaneously Diabetic Torii rat, a nonobese type 2 diabetic model, and nondiabetic Sprague-Dawley rats. In nondiabetic rats, Ipra increased urinary excretion of Na+ (UNaV) and fluid (UV) associated with increased food and fluid intake. Diabetes increased these four parameters, but Ipra had no further effect, probably because of its antihyperglycemic effect, such that glucosuria and, as a consequence, food and fluid intake were unchanged. Fluid balance and BFV, determined by bioimpedance spectroscopy, were similar among the four groups. To study the impact of food and fluid intake, nondiabetic rats were treated for 7 days with Veh, Ipra, or Ipra+pair feeding+pair drinking (Pair-Ipra). Pair-Ipra maintained a small increase in UV and UNaV versus Veh despite similar food and fluid intake. Pair-Ipra induced a negative fluid balance and decreased BFV, whereas Ipra or Veh had no significant effect compared with basal values. In conclusion, SGLT2 inhibition induces a sustained diuretic and natriuretic tone. Homeostatic mechanisms are activated to stabilize BFV, including compensatory increases in fluid and food intake.

Improving Dissolution Rate of Carbamazepine-Glutaric Acid Cocrystal Through Solubilization by Excess Coformer

PURPOSE

The use of soluble cocrystals is a promising strategy for delivering poorly soluble drugs. However, precipitation of poorly soluble crystal form during dissolution hinders the successful tablet development of cocrystals. This work was aimed to understand the mechanisms for improving dissolution performance of a soluble cocrystals by using excess coformer.

METHODS

A highly soluble carbamazepine (CBZ) cocrystal with- glutaric acid (GLA) was studied. Impact of excess GLA on solubility and intrinsic dissolution rate (IDR) was assessed. Viscosity of GLA solutions was also measured. Solid form of powders and pellets was examined using powder X-ray diffractometry. IDRs of cocrystal and GLA mixtures in different ratios were measured to identify a suitable formulation for maintaining high dissolution rate of CBZ-GLA in an aqueous environment.

RESULTS

IDR of CBZ-GLA in a pH 1.2 HCl solution was improved when GLA was present in the solution. Precipitation of CBZ·2H₂O was eliminated when GLA concentration was ≥100 mg/mL. The improved IDR was accompanied by higher solubility of CBZ in GLA solution and increased solution viscosity. The trend in IDR profile matched well with the solubility profile normalized by solution viscosity. Mixture of cocrystal and GLA led to improved IDR in simulated intestinal fluid.

CONCLUSIONS

The excess GLA increased the aqueous solubility of CBZ·2H₂O and, thereby, reduced the propensity to precipitation of CBZ·2H₂O during dissolution by lowering the degree of supersaturation. This strategy allowed development of a CBZ-GLA formulation with a significantly enhanced dissolution rate than CBZ-GLA.

Antidiabetic and antiobesity effects of SGLT2 inhibitor ipragliflozin in type 2 diabetic mice fed sugar solution

Obesity due to excessive calorie intake is a known aggravating factor contributing to the development and progression of type 2 diabetes. Recently, excessive intake of sugar-sweetened beverages has presented challenges in stemming the tide of obesity. Here, we investigated the possible effects of sugar solution intake on the antidiabetic effects of sodium-glucose cotransporter 2 (SGLT2) inhibitor ipragliflozin in type 2 diabetic mice that were fed ordinary drinking water, water + glucose solution, or water + sucrose solution. Under all feeding conditions, all mice exhibited type 2 diabetic symptoms, including hyperglycemia, hyperinsulinemia, and obesity; ipragliflozin subsequently improved these symptoms through increases in urinary glucose excretion. Effective dose of and response to ipragliflozin for diabetes improvement did not significantly differ by feeding condition. Further, under all feeding conditions, ipragliflozin administration resulted in significantly increased intake of both water and sugar solutions in association with increased urine volume resulting from increased urinary glucose excretion. In sugar solution-fed diabetic mice, ipragliflozin administration tended to slightly increase the proportion of sugar solution intake in total drinking volume, although not significantly so. In addition, ipragliflozin significantly decreased calorie balance, as calculated using calorie intake from food and sugar solution and calorie excretion via urinary glucose excretion. Our observation that the antidiabetic and antiobesity effects of the SGLT2 inhibitor ipragliflozin were not greatly affected by sugar solution intake in type 2 diabetic mice suggests that, in a clinical setting, ipragliflozin will remain an effective treatment for type 2 diabetic patients with excessive intake of carbohydrates.

Efficacy and safety of ipragliflozin in Japanese patients with type 2 diabetes receiving conventional therapy: clinical implication of the importance of exercise habits during treatment with ipragliflozin

Aims

To evaluate the efficacy and safety of ipragliflozin in Japanese patients with type 2 diabetes mellitus and inadequate glycemic control and investigate the impact of maintaining exercise habits during treatment.

Materials and methods

A total of 20 patients were enrolled. Patients aged 20-70 years with type 2 diabetes mellitus were administered 50 mg of ipragliflozin once daily for 12 weeks. The primary endpoint was the change in glycated hemoglobin levels from baseline to week 12. Key secondary endpoints included changes in total body weight, body composition, serum lipid levels, and diabetes therapy-related quality of life from baseline to week 12. Adverse events were recorded throughout the study.

Results

The patients' glycated hemoglobin levels were 0.69% lower at week 12 versus baseline (adjusted mean difference from baseline; P < 0.01, n = 18). Mean total body weight, body composition, and serum lipid levels also improved significantly from baseline. Of note, stratification analysis by physical activity level revealed slight but significant reductions in skeletal muscle mass and muscle mass, but not body fat mass, in the minimal exercise group compared to the data for the moderate exercise group. One of the subdomain structures in diabetes therapy-related quality of life questionnaire, "Anxiety and dissatisfaction with treatment," was significantly improved. Although no major hypoglycemic episodes occurred, two adverse events were reported.

Conclusions

Daily treatment with ipragliflozin was associated with marked improvements in glycemic control and body composition without major side effects, and this improvement was affected by exercise habits. This study was registered with UMIN CTR (no. UMIN000014388).

The Selective SGLT2 Inhibitor Ipragliflozin Has a Therapeutic Effect on Nonalcoholic Steatohepatitis in Mice

Background & Aims

In recent years, nonalcoholic steatohepatitis (NASH) has become a considerable healthcare burden worldwide. Pathogenesis of NASH is associated with type 2 diabetes mellitus (T2DM) and insulin resistance. However, a specific drug to treat NASH is lacking. We investigated the effect of the selective sodium glucose cotransporter 2 inhibitor (SGLT2I) ipragliflozin on NASH in mice.

Methods

We used the Amylin liver NASH model (AMLN), which is a diet-induced model of NASH that results in obesity and T2DM. AMLN mice were fed an AMLN diet for 20 weeks. SGLT2I mice were fed an AMLN diet for 12 weeks and an AMLN diet with 40 mg ipragliflozin/kg for 8 weeks.

Results

AMLN mice showed steatosis, inflammation, and fibrosis in the liver as well as obesity and insulin resistance, features that are recognized in human NASH. Ipragliflozin improved insulin resistance and liver injury. Ipragliflozin decreased serum levels of free fatty acids, hepatic lipid content, the number of apoptotic cells, and areas of fibrosis; it also increased lipid outflow from the liver.

Conclusions

Ipragliflozin improved the pathogenesis of NASH by reducing insulin resistance and lipotoxicity in NASH-model mice. Our results suggest that ipragliflozin has a therapeutic effect on NASH with T2DM.

Experimental diabetes induced by alloxan and streptozotocin: The current state of the art

Diabetes mellitus is a chronic metabolic disorder with a high prevalence worldwide. Animal models of diabetes represent an important tool in diabetes investigation that helps us to avoid unnecessary and ethically challenging studies in human subjects, as well as to obtain a comprehensive scientific viewpoint of this disease. Although there are several methods through which diabetes can be induced, chemical methods of alloxan- and streptozotocin-induced diabetes represent the most important and highly preferable experimental models for this pathological condition. Therefore, the aim of this article was to review the current knowledge related to quoted models of diabetes, including to this point available information about mechanism of action, particular time- and dose-dependent protocols, frequent problems, as well as major limitations linked to laboratory application of alloxan and sterptozotocin in inducing diabetes. Given that diabetes is known to be closely associated with serious health consequences it is of fundamental importance that current animal models for induction of diabetes should be continuously upgraded in order to improve overall prevention, diagnosis and treatment of this pathological condition.

Energy Balance After Sodium-Glucose Cotransporter 2 Inhibition

OBJECTIVE

Sodium-glucose cotransporter 2 (SGLT2) inhibitors cause substantially less weight loss than expected from the energy excreted via glycosuria. Our aim was to analyze this phenomenon quantitatively.

RESEARCH DESIGN AND METHODS

Eighty-six patients with type 2 diabetes (HbA1c 7.8 ± 0.8% [62 ± 9 mmol/mol], estimated glomerular filtration rate [eGFR] 89 ± 19 mL ⋅ min(-1) ⋅ 1.73 m(-2)) received empagliflozin (25 mg/day) for 90 weeks with frequent (n = 11) assessments of body weight, eGFR, and fasting plasma glucose (FPG). Time-dependent glucose filtration was calculated as the product of eGFR and FPG; time-dependent glycosuria was estimated from previous direct measurements. The relation of calorie-to-weight changes was estimated using a mathematical model of human energy metabolism that simulates the time course of weight change for a given change in calorie balance and calculates the corresponding energy intake changes.

RESULTS

At week 90, weight loss averaged -3.2 ± 4.2 kg (corresponding to a median calorie deficit of 51 kcal/day [interquartile range (IQR) 112]). However, the observed calorie loss through glycosuria (206 kcal/day [IQR 90]) was predicted to result in a weight loss of -11.3 ± 3.1 kg, assuming no compensatory changes in energy intake. Thus, patients lost only 29 ± 41% of the weight loss predicted by their glycosuria; the model indicated that this difference was accounted for by a 13% (IQR 12) increase in calorie intake (269 kcal/day [IQR 258]) coupled with a 2% (IQR 5) increase in daily energy expenditure (due to diet-induced thermogenesis). This increased calorie intake was inversely related to baseline BMI (partial r = -0.34, P < 0.01) and positively to baseline eGFR (partial r = 0.29, P < 0.01).

CONCLUSIONS

Chronic glycosuria elicits an adaptive increase in energy intake. Combining SGLT2 inhibition with caloric restriction is expected to be associated with major weight loss.

Ipragliflozin: first global approval

Ipragliflozin (Suglat® [Japan]), an orally active, next-generation sodium-glucose transporter 2 (SGLT2) inhibitor, has been developed by Astellas Pharma and Kotobuki Pharmaceutical for the treatment of type 2 diabetes mellitus. Ipragliflozin has received its first global approval in this indication in Japan, for use as monotherapy or in combination with another antihyperglycaemic agent (metformin, pioglitazone, a sulfonylurea, an α-glucosidase inhibitor, a dipeptidylpeptidase-4 inhibitor or nateglinide). Ipragliflozin is the first SGLT2 inhibitor to be approved in Japan. This article summarizes the milestones in the development of ipragliflozin leading to this first approval for the treatment of type 2 diabetes mellitus.

Inhibition of the glucose transporter SGLT2 with dapagliflozin in pancreatic alpha cells triggers glucagon secretion

Type 2 diabetes (T2D) is characterized by chronic hyperglycemia resulting from a deficiency in insulin signaling, because of insulin resistance and/or defects in insulin secretion; it is also associated with increases in glucagon and endogenous glucose production (EGP). Gliflozins, including dapagliflozin, are a new class of approved oral antidiabetic agents that specifically inhibit sodium-glucose co-transporter 2 (SGLT2) function in the kidney, thus preventing renal glucose reabsorption and increasing glycosuria in diabetic individuals while reducing hyperglycemia. However, gliflozin treatment in subjects with T2D increases both plasma glucagon and EGP by unknown mechanisms. In spite of the rise in EGP, T2D patients treated with gliflozin have lower blood glucose levels than those receiving placebo, possibly because of increased glycosuria; however, the resulting increase in plasma glucagon levels represents a possible concerning side effect, especially in a patient population already affected by hyperglucagonemia. Here we demonstrate that SGLT2 is expressed in glucagon-secreting alpha cells of the pancreatic islets. We further found that expression of SLC5A2 (which encodes SGLT2) was lower and glucagon (GCG) gene expression was higher in islets from T2D individuals and in normal islets exposed to chronic hyperglycemia than in islets from non-diabetics. Moreover, hepatocyte nuclear factor 4-α (HNF4A) is specifically expressed in human alpha cells, in which it controls SLC5A2 expression, and its expression is downregulated by hyperglycemia. In addition, inhibition of either SLC5A2 via siRNA-induced gene silencing or SGLT2 via dapagliflozin treatment in human islets triggered glucagon secretion through KATP channel activation. Finally, we found that dapagliflozin treatment further promotes glucagon secretion and hepatic gluconeogenesis in healthy mice, thereby limiting the decrease of plasma glucose induced by fasting. Collectively, these results identify a heretofore unknown role of SGLT2 and designate dapagliflozin an alpha cell secretagogue.

Ipragliflozin, an SGLT2 inhibitor, exhibits a prophylactic effect on hepatic steatosis and fibrosis induced by choline-deficient l-amino acid-defined diet in rats

Ipragliflozin is a selective sodium glucose cotransporter 2 (SGLT2) inhibitor that increases urinary glucose excretion by inhibiting renal glucose reabsorption and thereby causes a subsequent antihyperglycemic effect. As nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH), is closely linked to metabolic diseases such as obesity and diabetes, we investigated the effect of ipragliflozin on NAFLD in rats fed a choline-deficient l-amino acid-defined (CDAA) diet. Five weeks after starting the CDAA diet, rats exhibited hepatic triglyceride (TG) accumulation, fibrosis, and mild inflammation. Repeated oral administration of ipragliflozin (3mg/g, once daily for 5 weeks) prevented both hepatic TG accumulation (188 vs.290 mg/g tissue vehicle-treated group; P<0.001) and large lipid droplet formation. Further, ipragliflozin exerted a prophylactic effect on liver fibrosis, as indicated by a marked decrease in hydroxyproline content and fibrosis score. Pioglitazone, which is known to be effective on hepatic fibrosis in CDAA diet-fed rats as well as NASH patients with type 2 diabetes mellitus (T2DM), also exerted a mild prophylactic effect on fibrosis, but not on hepatic TG accumulation or inflammation. In conclusion, ipragliflozin prevented hepatic TG accumulation and fibrosis in CDAA-diet rats. These findings suggest the therapeutic potential of ipragliflozin for patients with NAFLD.

A randomized, double-blind, placebo-controlled study on long-term efficacy and safety of ipragliflozin treatment in patients with type 2 diabetes mellitus and renal impairment: results of the long-term ASP1941 safety evaluation in patients with type 2 diabetes with renal impairment (LANTERN) study

AIMS

To assess the effects of renal impairment (RI) on the efficacy and safety of ipragliflozin in patients with type 2 diabetes mellitus (T2DM).

METHODS

A cohort of Japanese patients with T2DM and mild to moderate RI and poor glycaemic control, despite diet/exercise therapy alone or diet/exercise therapy in combination with an oral hypoglycaemic agent (an α-glucosidase inhibitor, a sulfonylurea, or pioglitazone), were randomized in a double-blind manner to 50 mg ipragliflozin or placebo once daily for 24 weeks. The patients continued open-label ipragliflozin for a 28-week extension period (total treatment duration: 52 weeks).

RESULTS

Ipragliflozin significantly decreased glycated haemoglobin (HbA1c) and fasting plasma glucose (FPG) levels and body weight from baseline to week 24 (last observation carried forward) compared with placebo in all patients with RI. The decreases in HbA1c and FPG levels were statistically significant in patients with mild RI, but not in patients with moderate RI. Ipragliflozin significantly reduced body weight in both RI groups. The improvements in glycaemic control were maintained in the 28-week extension period. Ipragliflozin was associated with no clinically significant safety concerns, and its safety profiles were not influenced by the severity of RI.

CONCLUSIONS

Ipragliflozin significantly improved glycaemic control and body weight in patients with T2DM with mild RI, but did not improve glycaemic control in patients with moderate RI. Ipragliflozin is a valid treatment option for patients with mild RI but not those with moderate RI.

Sodium-Glucose linked transporter 2 (SGLT2) inhibitors--fighting diabetes from a new perspective

Sodium-Glucose linked transporter 2 (SGLT2) inhibitors are a new family of antidiabetic pharmaceutical agents whose action is based on the inhibition of the glucose reabsorption pathway, resulting in glucosuria and a consequent reduction of the blood glucose levels, in patients with type 2 diabetes mellitus. Apart from lowering both fasting and postprandial blood glucose levels, without causing hypoglycemia, SGLT2 inhibitors have also shown a reduction in body weight and the systolic blood pressure. This review paper explores the renal involvement in glucose homeostasis providing also the latest safety and efficacy data for the European Medicines Agency and U.S. Food and Drug Administration approved SGLT2 inhibitors, looking, finally, into the future of this novel antidiabetic category of pharmaceutical agents.

Coformer screening using thermal analysis based on binary phase diagrams

PURPOSE

The advent of cocrystals has demonstrated a growing need for efficient and comprehensive coformer screening in search of better development forms, including salt forms. Here, we investigated a coformer screening system for salts and cocrystals based on binary phase diagrams using thermal analysis and examined the effectiveness of the method.

METHODS

Indomethacin and tenoxicam were used as models of active pharmaceutical ingredients (APIs). Physical mixtures of an API and 42 kinds of coformers were analyzed using Differential Scanning Calorimetry (DSC) and X-ray DSC. We also conducted coformer screening using a conventional slurry method and compared these results with those from the thermal analysis method and previous studies.

RESULTS

Compared with the slurry method, the thermal analysis method was a high-performance screening system, particularly for APIs with low solubility and/or propensity to form solvates. However, this method faced hurdles for screening coformers combined with an API in the presence of kinetic hindrance for salt or cocrystal formation during heating or if there is degradation near the metastable eutectic temperature.

CONCLUSIONS

The thermal analysis and slurry methods are considered complementary to each other for coformer screening. Feasibility of the thermal analysis method in drug discovery practice is ensured given its small scale and high throughput.

SGLT2 selective inhibitor ipragliflozin reduces body fat mass by increasing fatty acid oxidation in high-fat diet-induced obese rats

Ipragliflozin is a novel and selective sodium-glucose cotransporter 2 (SGLT2) inhibitor that induces sustained increases in urinary glucose excretion by inhibiting renal glucose reabsorption and thereby exerting a subsequent antihyperglycemic effect. Here, we examined the effect of ipragliflozin on body weight in high-fat diet-induced (HFD) obese rats. Treatment of ipragliflozin (10mg/kg once daily) reduced body weight despite a slight increase in food intake. Dual-energy X-ray absorptiometry and computed tomography demonstrated that the reduction in body weight was accompanied by reduced visceral and subcutaneous fat masses but not lean mass or bone mineral content. Analysis of plasma and urinary parameters suggested the possibility that ipragliflozin enhanced lipolysis and fatty acid oxidation, and indirect calorimetry showed that ipragliflozin decreased the heat production rate from glucose but increased the rate from fat and lowered the respiratory exchange ratio. In conclusion, these data demonstrate that ipragliflozin-induced urinary glucose excretion specifically reduces fat mass with steady calorie loss by promoting the use of fatty acids instead of glucose as an energy source in HFD rats. By improving hyperglycemia and promoting weight reduction, ipragliflozin may prove useful in treating type 2 diabetes in obese individuals.

Metabolic response to sodium-glucose cotransporter 2 inhibition in type 2 diabetic patients

BACKGROUND

Sodium-glucose cotransporter 2 (SGLT2) inhibitors lower glycemia by enhancing urinary glucose excretion. The physiologic response to pharmacologically induced acute or chronic glycosuria has not been investigated in human diabetes.

METHODS

We evaluated 66 patients with type 2 diabetes (62 ± 7 years, BMI = 31.6 ± 4.6 kg/m(2), HbA1c = 55 ± 8 mmol/mol, mean ± SD) at baseline, after a single dose, and following 4-week treatment with empagliflozin (25 mg). At each time point, patients received a mixed meal coupled with dual-tracer glucose administration and indirect calorimetry.

RESULTS

Both single-dose and chronic empagliflozin treatment caused glycosuria during fasting (median, 7.8 [interquartile range {IQR}, 4.4] g/3 hours and 9.2 [IQR, 5.2] g/3 hours) and after meal ingestion (median, 29.0 [IQR, 12.5] g/5 hours and 28.2 [IQR, 15.4] g/5 hours). After 3 hours of fasting, endogenous glucose production (EGP) was increased 25%, while glycemia was 0.9 ± 0.7 mmol/l lower (P < 0.0001 vs. baseline). After meal ingestion, glucose and insulin AUC decreased, whereas the glucagon response increased (all P < 0.001). While oral glucose appearance was unchanged, EGP was increased (median, 40 [IQR, 14] g and 37 [IQR, 11] g vs. 34 [IQR, 11] g, both P < 0.01). Tissue glucose disposal was reduced (median, 75 [IQR, 16] g and 70 [IQR, 21] g vs. 93 [IQR, 18] g, P < 0.0001), due to a decrease in both glucose oxidation and nonoxidative glucose disposal, with a concomitant rise in lipid oxidation after chronic administration (all P < 0.01). β Cell glucose sensitivity increased (median, 55 [IQR, 35] pmol • min(-1) • m(-2) • mM(-1) and 55 [IQR, 39] pmol • min(-1) • m(-2) • mM(-1) vs. 44 [IQR, 32] pmol • min(-1) • m(-2) • mM(-1), P < 0.0001), and insulin sensitivity was improved. Resting energy expenditure rates and those after meal ingestion were unchanged.

CONCLUSIONS

In patients with type 2 diabetes, empagliflozin-induced glycosuria improved β cell function and insulin sensitivity, despite the fall in insulin secretion and tissue glucose disposal and the rise in EGP after one dose, thereby lowering fasting and postprandial glycemia. Chronic dosing shifted substrate utilization from carbohydrate to lipid. Trial registration. ClinicalTrials.Gov NCT01248364 (EudraCT no. 2010-018708-99). Funding. This study was funded by Boehringer Ingelheim.

Randomized, placebo-controlled, double-blind glycemic control trial of novel sodium-dependent glucose cotransporter 2 inhibitor ipragliflozin in Japanese patients with type 2 diabetes mellitus

Aims/Introduction

In the present dose–response study, we evaluated the efficacy and safety of ipragliflozin (ASP1941), a novel and selective inhibitor of sodium‐dependent glucose cotransporter 2, in Japanese patients with type 2 diabetes mellitus.

Materials and Methods

A total of 361 patients from 39 Japanese centers were randomized to receive either once‐daily oral ipragliflozin (12.5, 25, 50 or 100 mg) or a placebo for 12 weeks.

Results

All ipragliflozin‐treated groups had clinically significant, dose‐dependent decreases in glycated hemoglobin (HbA1c) and fasting plasma glucose levels compared with placebo‐treated groups. The adjusted mean difference in HbA1c change from baseline to the end of treatment between the placebo and 12.5, 25, 50, and 100 mg ipragliflozin groups were −0.61%, −0.97%, −1.29%, and −1.31%, respectively (P < 0.001). Reductions in HbA1c levels were similar between obese and non‐obese patients, and were larger in patients with baseline HbA1c ≥8.4% than in those with HbA1c <8.4%. Furthermore, bodyweight significantly (P < 0.001) and dose‐dependently decreased among ipragliflozin‐treated groups compared with the placebo group. The incidence of adverse events was similar across all groups. However, mild increases in hematocrit and blood urea nitrogen were found in ipragliflozin treated groups.

Conclusions

Once‐daily administration of ipragliflozin was dose‐dependently effective in glycemic control without major adverse effects. Ipragliflozin was equally effective between obese and non‐obese patients, and led to weight loss in both groups. Ipragliflozin was safe and well‐tolerated in Japanese patients with type 2 diabetes mellitus. This trial was registered with ClinicalTrials.gov (no. NCT00621868).

Effects of a new SGLT2 inhibitor, luseogliflozin, on diabetic nephropathy in T2DN rats

This study examined the effect of long-term control of hyperglycemia with a new sodium glucose cotransporter 2 inhibitor, luseogliflozin, given alone or in combination with lisinopril on the progression of renal injury in the T2DN rat model of type 2 diabetic nephropathy. Chronic treatment with luseogliflozin (10 mg/kg/day) produced a sustained increase in glucose excretion and normalized blood glucose and glycosylated hemoglobin levels to the same level as seen in the rats treated with insulin. It had no effect on blood pressure. In contrast, lisinopril (10 mg/kg/day) reduced mean blood pressure from 140 to 113 mmHg. Combination therapy significantly reduced blood pressure more than that seen in the rats treated with lisinopril. T2DN rats treated with vehicle exhibited progressive proteinuria, a decline in glomerular filtration rate (GFR), focal glomerulosclerosis, renal fibrosis, and tubular necrosis. Control of hyperglycemia with luseogliflozin prevented the fall in GFR and reduced the degree of glomerular injury, renal fibrosis, and tubular necrosis. In contrast, control of hyperglycemia with insulin had no effect on the progression of renal disease in T2DN rats. Reducing blood pressure with lisinopril prevented the fall in GFR and reduced proteinuria and the degree of glomerular injury and tubular necrosis. Combination therapy reduced the degree of glomerular injury, renal fibrosis, and tubular necrosis to a greater extent than administration of either drug alone. These results suggest that control of hyperglycemia with luseogliflozin slows the progression of diabetic nephropathy more than that seen with insulin, and combination therapy is more renoprotective than administration of either compound alone.

Animal models of diabetes mellitus for islet transplantation

Due to current improvements in techniques for islet isolation and transplantation and protocols for immunosuppressants, islet transplantation has become an effective treatment for severe diabetes patients. Many diabetic animal models have contributed to such improvements. In this paper, we focus on 3 types of models with different mechanisms for inducing diabetes mellitus (DM): models induced by drugs including streptozotocin (STZ), pancreatomized models, and spontaneous models due to autoimmunity. STZ-induced diabetes is one of the most commonly used experimental diabetic models and is employed using many specimens including rodents, pigs or monkeys. The management of STZ models is well established for islet studies. Pancreatomized models reveal different aspects compared to STZ-induced models in terms of loss of function in the increase and decrease of blood glucose and therefore are useful for evaluating the condition in total pancreatomized patients. Spontaneous models are useful for preclinical studies including the assessment of immunosuppressants because such models involve the same mechanisms as type 1 DM in the clinical setting. In conclusion, islet researchers should select suitable diabetic animal models according to the aim of the study.