Effects of SGLT2 selective inhibitor ipragliflozin on hyperglycemia, hyperlipidemia, hepatic steatosis, oxidative stress, inflammation, and obesity in type 2 diabetic mice. Eur J Pharmacol. 2013;715:246-255. [PMID: 23707905 DOI: 10.1016/j.ejphar.2013.05.014]

Evaluation of the effects of dapagliflozin, a sodium-glucose co-transporter-2 inhibitor, on hepatic steatosis and fibrosis using transient elastography in patients with type 2 diabetes and non-alcoholic fatty liver disease

AIMS

To investigate the effects of dapagliflozin on liver steatosis and fibrosis evaluated in patients with type 2 diabetes and non-alcoholic fatty liver disease (NAFLD).

MATERIALS AND METHODS

In a randomized, active-controlled, open-label trial, 57 patients with type 2 diabetes and NAFLD were randomized to a dapagliflozin group (5 mg/d; n = 33) or a control group (n = 24) and were treated for 24 weeks. Hepatic steatosis and fibrosis were assessed using transient elastography to measure controlled attenuation parameter (CAP) and liver stiffness, respectively.

RESULTS

Baseline liver stiffness measurement (LSM) was positively correlated with several markers and scoring systems for liver fibrosis. In week 24, there was a significant decrease in CAP from 314 ± 61 to 290 ± 73 dB/m (P = 0.0424) in the dapagliflozin group, while there was no significant change in the control group. In addition, LSM tended to decrease from 9.49 ± 6.05 to 8.01 ± 5.78 kPa in the dapagliflozin group. In 14 patients from this group with LSM values ≥8.0 kPa, indicating significant liver fibrosis, LSM decreased significantly from 14.7 ± 5.7 to 11.0 ± 7.3 kPa (P = 0.0158). Furthermore, serum alanine aminotransferase and γ-glutamyltranspeptidase levels decreased in the dapagliflozin group, but not in the control group, and visceral fat mass was significantly reduced in the dapagliflozin group.

CONCLUSIONS

Based on these findings, the sodium-glucose co-transporter-2 inhibitor dapagliflozin improves liver steatosis in patients with type 2 diabetes and NAFLD, and attenuates liver fibrosis only in patients with significant liver fibrosis, although the possibility cannot be excluded that a reduction in body weight or visceral adipose tissue by dapagliflozin may be associated with a decrease of liver steatosis or fibrosis.

Effect of ipragliflozin on liver function in Japanese type 2 diabetes mellitus patients: a subgroup analysis of the STELLA-LONG TERM study (3-month interim results)

This subgroup analysis of STELLA-LONG TERM, an ongoing 3-year post-marketing surveillance study on the long-term efficacy and safety of ipragliflozin, assessed the effect of ipragliflozin on liver function in type 2 diabetes mellitus (T2DM) patients. Patients were divided according to baseline liver function (normal [male: ALT ≤30, female: ALT ≤20], abnormal [male: ALT ≥31, female: ALT ≥21]). We evaluated changes in aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltransferase (γ-GTP), alkaline phosphatase (ALP), and fatty liver index (FLI) at 3 months of treatment; the proportion of patients with abnormal liver function whose liver function normalized after 3 months of treatment; and correlations between changes in ALT levels and efficacy variables/laboratory values. Liver function was normal in 2,570 and abnormal in 3,239 patients. Only patients with abnormal liver function showed a statistically/clinically significant decrease in AST, ALT, γ-GTP, and ALP levels at 3 months (all p < 0.05 vs. baseline). The FLI significantly decreased from 63.2677 ± 26.4363 (baseline) to 56.7137 ± 27.6484 (3 months) (p < 0.05) in the overall patient population. Liver function normalized in 20.5% (543/2,648) of patients with abnormal liver function. There was no obvious correlation between changes in ALT and changes in efficacy/laboratory parameters. Liver function improved after 3-month treatment with ipragliflozin in T2DM patients with abnormal liver function.

Impaired Vascular Redox Signaling in the Vascular Complications of Obesity and Diabetes Mellitus

Significance: Oxidative stress, a crucial regulator of vascular disease pathogenesis, may be involved in the vascular complications of obesity, systemic insulin resistance (IR), and diabetes mellitus (DM). Recent Advances: Excessive production of reactive oxygen species in the vascular wall has been linked with vascular disease pathogenesis. Recent evidence has revealed that vascular redox state is dysregulated in cases of obesity, systemic IR, and DM, potentially participating in the well-known vascular complications of these disease entities. Critical Issues: The detrimental effects of obesity and the metabolic syndrome on vascular biology have been extensively described at a clinical level. Further, vascular oxidative stress has often been associated with the presence of obesity and IR as well as with a variety of detrimental vascular phenotypes. However, the mechanisms of vascular redox state regulation under conditions of obesity and systemic IR, as well as their clinical relevance, are not adequately explored. In addition, the notion of vascular IR, and its relationship with systemic parameters of obesity and systemic IR, is not fully understood. In this review, we present all the important components of vascular redox state and the evidence linking oxidative stress with obesity and IR. Future Directions: Future studies are required to describe the cellular effects and the translational potential of vascular redox state in the context of vascular disease. In addition, further elucidation of the direct vascular effects of obesity and IR is required for better management of the vascular complications of DM.

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

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

Empagliflozin reverses obesity and insulin resistance through fat browning and alternative macrophage activation in mice fed a high-fat diet

OBJECTIVE

We reported previously that empagliflozin-a sodium-glucose cotransporter (SGLT) 2 inhibitor-exhibited preventive effects against obesity. However, it was difficult to extrapolate these results to human subjects. Here, we performed a therapeutic study, which is more relevant to clinical situations in humans, to investigate antiobesity effects of empagliflozin and illustrate the mechanism underlying empagliflozin-mediated enhanced fat browning in obese mice.

RESEARCH DESIGN AND METHODS

After 8 weeks on a high-fat diet (HFD), C57BL/6J mice exhibited obesity, accompanied by insulin resistance and low-grade chronic inflammation. Cohorts of obese mice were continued on the HFD for an additional 8-week treatment period with or without empagliflozin.

RESULTS

Treatment with empagliflozin for 8 weeks markedly increased glucose excretion in urine, and suppressed HFD-induced weight gain, insulin resistance and hepatic steatosis. Notably, empagliflozin enhanced oxygen consumption and carbon dioxide production, leading to increased energy expenditure. Consistently, the level of uncoupling protein 1 expression was increased in both brown and white (WAT) adipose tissues of empagliflozin-treated mice. Furthermore, empagliflozin decreased plasma levels of interleukin (IL)-6 and monocyte chemoattractant protein-1, but increased plasma levels of IL-33 and adiponectin in obese mice. Finally, we found that empagliflozin reduced M1-polarized macrophage accumulation, while inducing the anti-inflammatory M2 phenotype of macrophages in the WAT and liver, thereby attenuating obesity-related chronic inflammation.

CONCLUSIONS

Treatment with empagliflozin attenuated weight gain by increasing energy expenditure and adipose tissue browning, and alleviated obesity-associated inflammation and insulin resistance by alternative macrophage activation in the WAT and liver of obese mice.

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

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

Empagliflozin reduces blood pressure and uric acid in patients with type 2 diabetes mellitus: a systematic review and meta-analysis

The antidiabetic effect of empagliflozin in patients with type 2 diabetes mellitus has been explored in several trials. We performed this meta-analysis determining the effects of empagliflozin on blood pressure, uric acid, estimated glomerular filtration rate, blood lipids, blood glucose, and body weight in patients with type 2 diabetes mellitus. We searched three electronic databases (Pubmed, Web of Science, and Cochrane Central) for all published articles evaluating the effects of empagliflozin on blood glucose or blood pressure in subjects with type 2 diabetes mellitus. Total 5781 patients were included in 12 randomized controlled trials with a follow-up of 28 ± 22 weeks. Empagliflozin 10 or 25 mg reduced systolic and diastolic blood pressure, uric acid, hemoglobin A1c, fasting plasma glucose, and body weight in patients with type 2 diabetes mellitus (all p < 0.001). There were no differences for changes of estimated glomerular filtration rate between empagliflozin 10 or 25 mg and placebo in these patients (all p > 0.05). In conclusion, empagliflozin reduces systolic and diastolic blood pressure, uric acid, hemoglobin A1c, fasting plasma glucose, and body weight. These data suggest the beneficial effects of empagliflozin on these cardiovascular risk factors in patients with type 2 diabetes mellitus.

Sodium-Glucose Cotransporter-2 Inhibition in Type 2 Diabetes Mellitus: A Review of Large-Scale Cardiovascular Outcome Studies and Possible Mechanisms of Benefit

Cardiovascular (CV) disease remains the leading cause of morbidity and mortality in individuals with type 2 diabetes mellitus (T2DM). However, conventional antihyperglycemic medications seem to have minimal effect on lowering CV risk despite achieving excellent reductions in glycated hemoglobin A1c and associated reductions in microvascular risk. Sodium-glucose cotransporter 2 (SGLT2) inhibitors have emerged as noteworthy antihyperglycemic agents with concomitant CV and renal protection in T2DM patients. In this comprehensive review, we present the key CV findings from major large-scale outcome trials of SGLT2 inhibitors to date. We also review the mechanistic studies that might explain the CV benefits of SGLT2 inhibition in patients with T2DM.

A review of the anti-inflammatory properties of antidiabetic agents providing protective effects against vascular complications in diabetes

The global prevalence of Type 2 diabetes mellitus and its associated complications are growing rapidly. Although the role of hyperglycemia is well recognized in the pathophysiology of diabetic complications, its exact underlying mechanisms are not fully understood. In this regard, accumulating evidence suggests that the role of inflammation appears pivotal, with studies showing that most diabetic complications are associated with an inflammatory response. Several classes of antidiabetic agents have been introduced for controlling glycemia, with evidence that these pharmacological agents may have modulatory effects on inflammation beyond their glucose-lowering activity. Here we review the latest evidence on the anti-inflammatory effects of commonly used antidiabetic medications and discuss the relevance of these effects on preventing diabetic complications.

Antidiabetic Drugs in NAFLD: The Accomplishment of Two Goals at Once?

Non-Alcoholic Fatty Liver Disease (NAFLD) is the most common cause of chronic liver disease in Western countries, accounting for 20–30% of general population and reaching a prevalence of 55% in patients with type 2 diabetes mellitus (T2DM). Insulin resistance plays a key role in pathogenic mechanisms of NAFLD. Many drugs have been tested but no medications have yet been approved. Antidiabetic drugs could have a role in the progression reduction of the disease. The aim of this review is to summarize evidence on efficacy and safety of antidiabetic drugs in patients with NAFLD. Metformin, a biguanide, is the most frequently used drug in the treatment of T2DM. To date 15 randomized controlled trials (RCTs) and four meta-analysis on the use of metformin in NAFLD are available. No significant improvement in histological liver fibrosis was shown, but it can be useful in the treatment of co-factors of NAFLD, like body weight, transaminase or cholesterol levels, and HbA1c levels. A possible protective role in various types of cancer has been reported for Metformin. Thiazolidinediones modulate insulin sensitivity by the activation of PPAR-γ. The RCTs and the meta-analysis available about the role of these drugs in NAFLD show an improvement in ballooning, lobular inflammation, and perhaps fibrosis, but some side effects, in particular cardiovascular, were showed. GLP-1 analogues stimulate insulin secretion by pancreatic beta cell and inhibit glucagon release; Liraglutide is the most used drug in this class and significantly improves steatosis, hepatocyte ballooning and transaminase levels. Scanty data about the role of DPP-4 and SGLT inhibitors were published. No data about insulin effects on NAFLD are available but it was showed a possible association between insulin use and the development of solid neoplasms, in particular HCC. In conclusion, antidiabetic drugs seem to be promising drugs, because they are able to treat both NAFLD manifestations and diabetes, preventing worsening of hepatic damage, but data are still conflicting. All antidiabetic drugs can be safely used in patients with compensated cirrhosis, while insulin is the preferred drug in decompensated Child C cirrhosis.

Effect of canagliflozin on nocturnal home blood pressure in Japanese patients with type 2 diabetes mellitus: The SHIFT-J study

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have beneficial effects on several cardiometabolic biomarkers, but this is not sufficient to fully explain the significant reduction in cardiovascular risk and mortality reported with SGLT2 inhibitor treatment in patients with diabetes mellitus. The 8-week, randomized, open-label SHIFT-J study investigated the effects of adding canagliflozin vs intensified antihyperglycemic therapy on nocturnal home blood pressure (BP) in patients with poorly controlled type 2 diabetes and nocturnal BP on existing therapy. Patients were randomized to oral canagliflozin 100 mg/d or control (increased hypoglycemic dosage/addition of another hypoglycemic agent). The efficacy analysis included 78 patients (mean 69 years; 59% male). Nocturnal home systolic BP [HSBP] decreased by 5.23 mm Hg in the canagliflozin group and by 1.04 mm Hg in the control group (P = 0.078 for between-group difference in change from baseline to week 8 [primary endpoint]); corresponding decreases in HSBP from baseline to week 4 were 5.08 and 1.38 mm Hg, respectively (P = 0.054). Reductions in morning HSBP from baseline to week 4 (-6.82 mm Hg vs -1.26 mm Hg, P = 0.038) and evening HSBP from baseline to week 8 (-8.74 mm Hg vs -2.36 mm Hg, P = 0.012) were greater in the canagliflozin group than in the control group. Body mass index (P < 0.001) and N-terminal pro B-type natriuretic peptide level (NT-proBNP; P = 0.023) decreased more in the canagliflozin group than in the control group. Glycemic control improved comparably in both groups. Reduction of HSBP and NT-proBNP level may be potential mechanism by which SGLT2 inhibitors reduce cardiovascular event risk.

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.

Ipragliflozin Ameliorates Liver Damage in Non-alcoholic Fatty Liver Disease

Background

There are few effective medications for non-alcoholic steatohepatitis (NASH). We investigated the efficacy of ipragliflozin (selective sodium-glucose cotransporter-2 inhibitor [SGLT2I]) for the treatment of patients with type 2 diabetes mellitus (T2DM) complicated by non-alcoholic fatty liver disease (NAFLD).

Methods

We prospectively enrolled patients with T2DM complicated by NAFLD treated at our institutions from January 2015 to December 2016. Patients received oral ipragliflozin (50 mg/day) once daily for 24 weeks. Body composition was evaluated using an InBody720 analyzer. We used transient elastography to measure liver stiffness and the controlled attenuation parameter for the quantification of liver steatosis in patients with NASH.

Results

Forty-three patients with T2DM and NAFLD were enrolled (12 with biopsy-proven NASH and 31 with NAFLD diagnosed by ultrasonography). After 24 weeks, body weight, hemoglobin A1c (HbA1c), aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transpeptidase, body fat mass, and steatosis were significantly decreased compared to baseline measurements in patients with NASH. However, muscle mass was not reduced, and liver stiffness showed a statistically insignificant tendency to decrease. NAFLD patients also showed a significant reduction in body weight, HbA1c, AST, and ALT compared to baseline measurements.

Conclusion

Ipragliflozin may be effective in patients with T2DM complicated by NAFLD.

Sodium-glucose cotransporter-2 inhibition for the reduction of cardiovascular events in high-risk patients with diabetes mellitus

Patients with type 2 diabetes mellitus (T2DM) exhibit an increased risk for cardiovascular (CV) events. Hyperglycemia itself contributes to the pathogenesis of atherosclerosis and heart failure (HF) in these patients, but glucose-lowering strategies studied to date have had little or no impact on reducing CV risk, especially in patients with a long duration of T2DM and prevalent CV disease (CVD). Sodium-glucose cotransporter-2 (SGLT2) inhibitors are the new class of glucose-lowering medications that increase urinary glucose excretion, thus improving glycemic control, independent of insulin. The recently published CV outcome trial, Empagliflozin Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients-Removing Excess Glucose (EMPA-REG OUTCOME), demonstrated that the SGLT2 inhibitor empagliflozin significantly reduced the combined CV end point of CV death, nonfatal myocardial infarction, and nonfatal stroke vs. placebo in a population of patients with T2DM and prevalent atherosclerotic CVD. In addition, and quite unexpectedly, empagliflozin significantly and robustly reduced the individual end points of CV death, overall mortality, and hospitalization for HF in this high-risk population. Several beneficial factors beyond glucose control, such as weight loss, lowering blood pressure, sodium depletion, renal hemodynamic effects, effects on myocardial energetics, and/or neurohormonal effects, have been seen with SGLT2 inhibition.

Effect of Dapagliflozin on Alanine Aminotransferase Improvement in Type 2 Diabetes Mellitus with Non-alcoholic Fatty Liver Disease

BACKGROUND

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are expected to improve the liver function of patients with non-alcoholic fatty liver disease (NAFLD) combined type 2 diabetes mellitus (T2DM) by its characteristic mechanism. This study was designed to investigate the effect of dapagliflozin, one of the SGLT2i, on the liver function of T2DM with NAFLD when combined with metformin.

METHODS

Among patients who received dual oral hypoglycemic agents within the 3 months of diagnosing NAFLD, patients who had abnormal alanine aminotransferase (ALT) level (>40 IU/L) were included. Patients were divided into two groups: metformin+dapagliflozin group and metformin+dipeptidyl peptidase-4 inhibitors (DPP4i) group. Demographic data, biochemical data and the clinical and treatment histories of all patients were reviewed.

RESULTS

A total of 102 patients were included (dapagliflozin group, n=50; DPP4i group, n=52). Dapagliflozin group showed more weight loss and more ALT decline than DPP4i group (-2.9 kg vs. -0.4 kg, P=0.005; -21.1 U/L vs. -9.5 U/L, P=0.008, respectively) and the proportion of patients with ALT normalization after treatment was also significantly higher in the dapagliflozin group (80.0% vs. 61.5%, P=0.041). The effect of dapagliflozin with metformin on ALT normalization remained significant after adjustment for confounding variables including body weight loss (odds ratio, 3.489; P=0.046).

CONCLUSION

ALT improvement was statistically significant in the dapagliflozin than the DPP4i when combined with metformin and the result was consistent after adjustment for confounding variables including body weight loss.

Effects of canagliflozin versus glimepiride on adipokines and inflammatory biomarkers in type 2 diabetes

OBJECTIVE

Type 2 diabetes and obesity are pro-inflammatory states associated with increased risk of cardiovascular disease. Canagliflozin, an SGLT2 inhibitor, demonstrated superiority in lowering HbA1c versus glimepiride with less hypoglycemia and greater weight reduction via loss of fat mass in a 52-week trial of type 2 diabetes patients. This post hoc, exploratory analysis assessed the effects of canagliflozin versus glimepiride on select adipokines, inflammatory biomarkers, and chemokines.

METHODS

Changes from baseline to Week 52 in serum leptin, adiponectin, IL-6, TNFα, CRP, PAI-1, VCAM-1, and MCP-1 were measured in a randomly selected subset of type 2 diabetes patients on metformin receiving canagliflozin 300 mg (n = 100) or glimepiride (n = 100) in the overall study. Correlations between change in biomarkers and change in select metabolic and anthropometric variables were assessed.

RESULTS

At Week 52, canagliflozin decreased median serum leptin by 25% (95% CI: -34%, -15%) and increased median serum adiponectin by 17% (95% CI: 11%, 23%) compared with glimepiride. There was a 22% reduction in median serum IL-6 (95% CI: -34%, -10%) and a 7% increase in median serum TNFα (95% CI: 1%, 12%) with canagliflozin versus glimepiride. No between-group differences were observed with the other biomarkers. The decrease in serum leptin with canagliflozin was correlated with change in weight (r ≥ 0.3) only; the increase in adiponectin and decrease in IL-6 with canagliflozin occurred independently of changes in HbA1c, weight, or lipids.

CONCLUSIONS

These results indicate that canagliflozin may improve adipose tissue function and induce changes in serum leptin, adiponectin, and IL-6 that favorably impact insulin sensitivity and cardiovascular disease risk.

Effect of Empagliflozin on Liver Fat in Patients With Type 2 Diabetes and Nonalcoholic Fatty Liver Disease: A Randomized Controlled Trial (E-LIFT Trial)

OBJECTIVE

Sodium-glucose cotransporter 2 (SGLT-2) inhibitors have been shown to reduce liver fat in rodent models. Data regarding the effect of SGLT-2 inhibitors on human liver fat are scarce. This study examined the effect of empagliflozin (an SGLT-2 inhibitor) on liver fat in patients with type 2 diabetes and nonalcoholic fatty liver disease (NAFLD) by using MRI-derived proton density fat fraction (MRI-PDFF).

RESEARCH DESIGN AND METHODS

Fifty patients with type 2 diabetes and NAFLD were randomly assigned to either the empagliflozin group (standard treatment for type 2 diabetes plus empagliflozin 10 mg daily) or the control group (standard treatment without empagliflozin) for 20 weeks. Change in liver fat was measured by MRI-PDFF. Secondary outcome measures were change in alanine transaminase (ALT), aspartate transaminase (AST), and γ-glutamyl transferase (GGT) levels.

RESULTS

When included in the standard treatment for type 2 diabetes, empagliflozin was significantly better at reducing liver fat (mean MRI-PDFF difference between the empagliflozin and control groups -4.0%; P < 0.0001). Compared with baseline, significant reduction was found in the end-of-treatment MRI-PDFF for the empagliflozin group (16.2% to 11.3%; P < 0.0001) and a nonsignificant change was found in the control group (16.4% to 15.5%; P = 0.057). The two groups showed a significant difference for change in serum ALT level (P = 0.005) and nonsignificant differences for AST (P = 0.212) and GGT (P = 0.057) levels.

CONCLUSIONS

When included in the standard treatment for type 2 diabetes, empagliflozin reduces liver fat and improves ALT levels in patients with type 2 diabetes and NAFLD.

Effects of the SGLT-2 inhibitor dapagliflozin on glomerular and tubular injury markers

The mechanisms by which SGLT-2 inhibitors lower albuminuria are incompletely understood. We assessed in a post-hoc analysis of a cross-over trial the effects of the SGLT2 inhibitor dapagliflozin on glomerular markers (IgG to IgG4 and IgG to albumin), tubular markers (urinary KIM-1, NGAL and LFABP) and inflammatory markers (urinary MCP-1 and IL-6) to provide more insight into kidney protective effects. Dapagliflozin decreased albuminuria by 43.9% (95% CI, 30.3%-54.8%) and eGFR by 5.1 (2.0-8.1) mL/min/1.73m2 compared to placebo. Dapagliflozin did not change glomerular charge or size selectivity index compared to placebo. Dapagliflozin decreased urinary KIM-1 excretion by 22.6% (0.3%-39.8%; P = .05) and IL-6 excretion by 23.5% (1.4%-40.6%; P = .04) compared to placebo, whereas no changes in NGAL, LFABP and MCP-1 were observed. During dapagliflozin treatment, changes in albuminuria correlated with changes in eGFR (r = 0.36; P = .05) and KIM-1 (r = 0.39; P = .05). In conclusion, the albuminuria-lowering effect of 6 weeks of dapagliflozin therapy may be the result of decreased intraglomerular pressure or reduced tubular cell injury.

Improved cardiometabolic risk factors in Japanese patients with type 2 diabetes treated with ipragliflozin: a pooled analysis of six randomized, placebo-controlled trials

To examine differential improvements among cardiovascular risk factors in response to treatment with ipragliflozin in Japanese type 2 diabetes mellitus (T2DM) patients, we conducted a pooled analysis of six randomized, double-blind trials of Japanese T2DM patients who received ipragliflozin 50 mg/day or placebo and had patient-level data for cardiometabolic risk parameters. Risk factors included glycated hemoglobin (HbA1c), body weight, homeostatic model assessment for insulin resistance and beta-cell function (HOMA-R and HOMA-beta, respectively), systolic blood pressure, fasting serum insulin concentrations, and the concentration of uric acid, lipids, and liver enzymes from baseline to end of treatment (EOT; 12-24 weeks). The primary endpoint of each trial was the change in HbA1c from baseline to EOT. Changes in risk factors from baseline to EOT were compared between ipragliflozin-treated and placebo groups, and between two subgroups (high- and low-risk groups for each parameter). All parameters, except low-density lipoprotein cholesterol (LDL-C) and non high-density lipoprotein cholesterol (non HDL-C), improved significantly in the ipragliflozin group. Subgroup analysis revealed a significantly greater improvement in the high-risk group versus low-risk group in HbA1c, HOMA-R, HOMA-beta, aspartate transaminase, alanine transaminase, and gamma-glutamyltransferase, but not in any of the lipid parameters or blood pressure. Liver function improvement in the ipragliflozin group was significantly correlated with changes in body weight, HbA1c, HOMA-beta, and HOMA-R. This analysis demonstrated that, in Japanese T2DM patients, ipragliflozin 50 mg/day was associated with improvements in cardiometabolic risk factors, except for LDL-C and non HDL-C.

Canagliflozin attenuates the progression of atherosclerosis and inflammation process in APOE knockout mice

Background

Sodium glucose co-transporter2 inhibitors reduce the incidence of cardiovascular events in patients with type 2 diabetes mellitus based on the results of recent cardiovascular outcome studies. Herein, we investigated the effects of long-term treatment with canagliflozin on biochemical and immunohistochemical markers related to atherosclerosis and atherosclerosis development in the aorta of apolipoprotein E knockout (Apo-E^(−/−)) mice.

Methods

At the age of 5 weeks, mice were switched from normal to a high-fat diet. After 5 weeks, Apo-E^(−/−) mice were divided into control-group (6 mice) treated with 0.5% hydroxypropyl methylcellulose and Cana-group (7 mice) treated with canagliflozin (10 mg/kg per day) per os. After 5 weeks of intervention, animals were sacrificed, and heart and aorta were removed. Sections stained with hematoxylin–eosin (H&E) were used for histomorphometry whereas Masson’s stained tissues were used to quantify the collagen content. Immunohistochemistry to assess MCP-1, CD68, a-smooth muscle actin, MMP-2, MMP-9, TIMP-1 and TIMP-2 expression was carried out and q-PCR experiments were performed to quantify mRNA expression.

Results

Canagliflozin-group mice had lower total-cholesterol, triglycerides and glucose levels (P < 0.01), while heart rate was significantly lower (P < 0.05). Histomorphometry revealed that one in seven Cana-group mice versus four in six control mice developed atheromatosis, while aortic root plaque was significantly less, and collagen was 1.6 times more intense in canagliflozin-group suggesting increased plaque stability. Immunohistochemistry revealed that MCP-1 was significantly less expressed (P < 0.05) in the aortic root of canagliflozin-group while reduced expression of a-actin and CD68 was not reaching significance (P = 0.15). VCAM-1 and MCP-1 mRNA levels were lower (P = 0.02 and P = 0.07, respectively), while TIMP-1/MMP-2 ratio expression was higher in canagliflozin-group approaching statistical significance (P = 0.07).

Conclusions

Canagliflozin attenuates the progression of atherosclerosis, reducing (1) hyperlipidemia and hyperglycemia, and (2) inflammatory process, by lowering the expression of inflammatory molecules such as MCP-1 and VCAM-1. Moreover, canagliflozin was found to increase the atherosclerotic plaque stability via increasing TIMP-1/MMP-2 ratio expression.

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0749-1) contains supplementary material, which is available to authorized users.

SGLT2 Inhibitors and Cardiovascular Outcomes: Current Perspectives and Future Potentials

PURPOSE OF REVIEW

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have been shown to exert benefit on cardiac outcomes. In this review, we provide updates on available clinical data, studies on potential mechanisms for the CV effects, as well as discuss potential clinical implications of these new findings.

RECENT FINDINGS

Since the publications of the EMPA-REG and CANVAS trials, large multi-national cohort studies have further shown the cardioprotective effects of SGLT2i. Moreover, new studies examining SGLT2i action on sodium-hydrogen exchanger proteins in both the heart and the kidney, on myocardial energetics and impact on inflammation and atherosclerosis continue to shed light on the multitude of pleotropic effects of these agents. Though more data is needed to substantiate the safety and efficacy, SGLT2i should be considered as a valuable therapy to help reduce CV risk in patients with diabetes. Ultimately, SGLT2i may have utility in preventing progression to diabetes or providing CV protection in patients who do not have diabetes.

Effects of the SGLT2 inhibitor ipragliflozin on food intake, appetite-regulating hormones, and arteriovenous differences in postprandial glucose levels in type 2 diabetic rats

AIMS

The sodium-glucose cotransporter (SGLT) 2 inhibitor, ipragliflozin, improves not only hyperglycemia but also obesity in type 2 diabetic animals and patients; however, there have been concerns that it may also cause an increase in compensatory food intake. Appetite is regulated by complex mechanisms involving the central nervous system, part of which involves appetite-related hormones and arteriovenous differences in postprandial glucose levels. We evaluated the effect of ipragliflozin in type 2 diabetic rats on food intake, appetite-related hormones and arteriovenous differences in postprandial glucose levels, and their correlation with food intake.

MAIN METHODS

Ipragliflozin and several antidiabetic drugs were administered to type 2 diabetic rats and various parameters concerning food intake were measured.

KEY FINDINGS

Ipragliflozin significantly increased urinary glucose excretion and reduced postprandial hyperglycemia. Compared to normal rats, diabetic rats exhibited hyperphagia and elevated plasma levels of the appetite-stimulating hormones neuropeptide Y and ghrelin. Ipragliflozin induced significant weight loss and reduced plasma levels of appetite-stimulating hormones without affecting food intake. Diabetic rats exhibited a significantly reduced arteriovenous difference in postprandial glucose levels due to insulin insufficiency; this was improved by ipragliflozin, which increased renal arteriovenous differences in glucose levels by increasing urinary glucose excretion.

SIGNIFICANCE

These results indicate that the SGLT2 inhibitor, ipragliflozin, exerts antihyperglycemic actions by increasing urinary glucose excretion, and induces weight loss without a compensatory increase in food intake in type 2 diabetic mice. The mechanisms underlying these effects can be attributed, in part, to an increased arteriovenous difference in postprandial glucose levels and improved regulation of appetite-related hormones in the diabetic animal model. While this study was conducted in rodents and the results may be distinct from those in humans, it is possible that some of the pharmacological mechanisms, including the regulation of appetite-related hormones, can be extrapolated to clinical settings and may be valuable for further studies including clinical investigations.

Molecular Mechanisms Underlying the Cardiovascular Benefits of SGLT2i and GLP-1RA

PURPOSE OF REVIEW

In addition to their effects on glycemic control, two specific classes of relatively new anti-diabetic drugs, namely the sodium glucose co-transporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1RA) have demonstrated reduced rates of major adverse cardiovascular events (MACE) in subjects with type 2 diabetes (T2D) at high risk for cardiovascular disease (CVD). This review summarizes recent experimental results that inform putative molecular mechanisms underlying these benefits.

RECENT FINDINGS

SGLT2i and GLP-1RA exert cardiovascular effects by targeting in both common and distinctive ways (A) several mediators of macro- and microvascular pathophysiology: namely (A1) inflammation and atherogenesis, (A2) oxidative stress-induced endothelial dysfunction, (A3) vascular smooth muscle cell reactive oxygen species (ROS) production and proliferation, and (A4) thrombosis. These agents also exhibit (B) hemodynamic effects through modulation of (B1) natriuresis/diuresis and (B2) the renin-angiotensin-aldosterone system. This review highlights that while GLP-1RA exert direct effects on vascular (endothelial and smooth muscle) cells, the effects of SGLT2i appear to include the activation of signaling pathways that prevent adverse vascular remodeling. Both SGLT2i and GLP-1RA confer hemodynamic effects that counter adverse cardiac remodeling.

SGLT-2 inhibitors in Diabetic Kidney Disease: What Lies Behind their Renoprotective Properties?

BACKGROUND

Despite optimal management of diabetic kidney disease (DKD) with intensive glycemic control and administration of agents blocking the renin-angiotensinaldosterone- system, the residual risk for nephropathy progression to end-stage-renal-disease (ESRD) remains high. Sodium-glucose co-transporter type 2 (SGLT-2)-inhibitors represent a newly-introduced anti-diabetic drug class with pleiotropic actions extending above their glucose-lowering efficacy. Herein, we provide an overview of preclinical and clinical-trial evidence supporting a protective effect of SGLT-2 inhibitors on DKD.

METHODS

A systematic literature search of bibliographic databases was conducted to identify preclinical studies and randomized trials evaluating the effects SGLT-2 inhibitors on DKD.

RESULTS

Preclinical studies performed in animal models of DKD support the renoprotective action of SGLT-2 inhibitors showing that these agents exert albuminuria-lowering effects and reverse glomerulosclerosis. The renoprotective action of SGLT-2 inhibitors is strongly supported by human studies showing that these agents prevent the progression of albuminuria and retard nephropathy progression to ESRD. This beneficial effect of SGLT-2 inhibitors is not fully explained by their glucose-lowering properties. Attenuation of glomerular hyperfiltration and improvement in a number of surrogate risk factors, including associated reduction in systemic blood pressure, body weight, and serum uric acid levels may represent plausible mechanistic explanations for the cardio-renal protection offered by SGLT-2 inhibitors. Furthermore, the tubular cell metabolism seems to be altered towards a ketone-prone pathway with protective activities.

CONCLUSION

SGLT-2 inhibition emerges as a novel therapeutic approach of diabetic with anticipated benefits towards cardio-renal risk reduction. Additional research efforts are clearly warranted to elucidate this favorable effect in patients with overt DKD.

Exploring novel pharmacotherapeutic applications and repurposing potential of sodium glucose CoTransporter 2 inhibitors

Sodium glucose cotransporter 2 (SGLT2) inhibitors are a relatively new class of anti-hyperglycaemic drugs with a distinctive mechanism of action focusing on renal absorption of glucose. Apart from its anti-hyperglycaemic effects, a multitude of research studies on this class have revealed that these drugs have far more versatile and comprehensive pharmacological effects than previously believed. Approximately 30% of FDA approved drugs are repurposed and used for indications other than those for which they were initially intended. Repurposing already approved drugs leads to significant reduction in pre-clinical and clinical R&D costs as well as minimizing the burden with respect to obtaining regulatory approval. SGLT2 inhibitors have been found to exhibit cardioprotective, renoprotective, anti-hyperlipidaemic, anti-atherosclerotic, anti-obesity, anti-neoplastic, hepatoprotective, and renoprotective effects in in vitro, pre-clinical, and clinical studies. The pleiotropic effects of this class have been attributed to a variety of its pharmacodynamic actions such as natriuresis, haemoconcentration, deactivation of RAAS, ketone body formation, alterations in energy homeostasis, glycosuria, lipolysis, anti-inflammatory, and anti-oxidative actions. These favourable observations encourage further research on this multifaceted class in order to effectively explore and harness its full potential and consequently lead to clinical outcomes.

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

Background

Type 2 diabetes (T2D) is associated with generalized vascular dysfunction characterized by increases in large artery stiffness, endothelial dysfunction, and vascular smooth muscle dysfunction. Sodium glucose cotransporter 2 inhibitors (SGLT2i) represent the most recently approved class of oral medications for the treatment of T2D, and have been shown to reduce cardiovascular and overall mortality. Although it is currently unclear how SGLT2i decrease cardiovascular risk, an improvement in vascular function is one potential mechanism. The aim of the current study was to examine if dapagliflozin, a widely prescribed STLT2i, improves generalized vascular dysfunction in type 2 diabetic mice. In light of several studies demonstrating a bi-directional relation between orally ingested medications and the gut microbiota, a secondary aim was to determine the effects of dapagliflozin on the gut microbiota.

Methods

Male diabetic mice (Db, n = 24) and control littermates (Con; n = 23) were randomized to receive either a standard diet or a standard diet containing dapagliflozin (60 mg dapagliflozin/kg diet; 0.006%) for 8 weeks. Arterial stiffness was assessed by aortic pulse wave velocity; endothelial function and vascular smooth muscle dysfunction were assessed by dilatory responses to acetylcholine and sodium nitroprusside, respectively.

Results

Compared to untreated diabetic mice, diabetic mice treated with dapagliflozin displayed significantly lower arterial stiffness (Db = 469 cm/s vs. Db + dapa = 435 cm/s, p < 0.05), and improvements in endothelial dysfunction (area under the curve [AUC] Db = 57.2 vs. Db + dapa = 117.0, p < 0.05) and vascular smooth muscle dysfunction (AUC, Db = 201.7 vs. Db + dapa = 285.5, p < 0.05). These vascular improvements were accompanied by reductions in hyperglycemia and circulating markers of inflammation. The microbiota of Db and Con mice were distinctly different, and dapagliflozin treatment was associated with minor alterations in gut microbiota composition, particularly in Db mice, although these effects did not conclusively mediate the improvements in vascular function.

Conclusions

Dapagliflozin treatment improves arterial stiffness, endothelial dysfunction and vascular smooth muscle dysfunction, and subtly alters microbiota composition in type 2 diabetic mice. Collectively, the improvements in generalized vascular function may represent an important mechanism underlying the cardiovascular benefits of SGLT2i treatment.

Prevention of progression of diabetic nephropathy by the SGLT2 inhibitor ipragliflozin in uninephrectomized type 2 diabetic mice

Diabetic nephropathy is the leading cause of end-stage renal disease in the world. Although recent development of sodium-glucose cotransporter (SGLT) 2 inhibitors offers a new antidiabetic therapeutic strategy, it remains unclear whether such treatments are beneficial for limiting the progression of type 2 diabetic overt nephropathy. This study examined the effect of the SGLT2 inhibitor ipragliflozin on the progression of nephropathy in uninephrectomized KK/A^y type 2 diabetic mice, which exhibit not only typical diabetic symptoms such as hyperglycemia, hyperinsuemia, glucose intolerance, insulin resistance, hyperlipidemia, inflammation, and obesity, but also moderate hypertension and overt nephropathy with decline in renal function. Four-week repeated administration of ipragliflozin improved various diabetic symptoms, including hyperglycemia, insulin resistance, and inflammation by increasing urinary glucose excretion. In addition, ipragliflozin ameliorated albuminuria/proteinuria; decline in renal function, as measured by creatinine clearance; hypertension; and renal injury, including glomerulosclerosis and interstitial fibrosis. These effects were significant at doses of 1 mg/kg or higher and were similar to those observed following administration of losartan (30 mg/kg). These results suggest that the SGLT2 inhibitor ipragliflozin prevents progression to diabetic overt nephropathy in uninephrectomized type 2 diabetic mice. SGLT2 inhibitors may therefore represent a promising therapeutic option for the management of type 2 diabetes to slow the progression of diabetic nephropathy.

SGLT-2 Inhibitors: Are They a Promising Treatment Option in T2DM Patients with NAFLD?

Sodium glucose co-transporter type 2 inhibitors (SGLT-2 inhibitors) are a class of antidiabetics, recently approved for the treatment of patients with T2DM. They feature cardioprotective and renoprotective action, while they exert beneficial effects on metabolic parameters. Non-alcoholic fatty liver disease (NAFLD) is a frequent co-morbidity in diabetic patients. Its prevalence reaches up to 70%. Since there is no specific treatment approved for NAFLD, both experimental and clinical studies have been recently conducted highlighting the efficacy and safety of SGLT-2 inhibitors mainly in animal models and secondarily in patients with T2DM and NAFLD. This class of antidiabetics seems very attractive, improving both glycemic control and liver function tests, while inhibiting NAFLD progression. However, further investigation is required to establish them as a first-line treatment option in T2DM patients with NAFLD, after thorough assessment of their efficacy and safety in clinical practice.

Renal protective effect of SGLT2 inhibitor dapagliflozin alone and in combination with irbesartan in a rat model of diabetic nephropathy

Considering the complementary mechanisms of SGLT2 inhibitors and angiotensin inhibitors on kidney, it is postulated that combination of both agents could afford greater protection against diabetic renal injury. So, we investigated renal protective effects of SGLT2 inhibitor, dapagliflozin, alone and in combination with irbesartan in a rat model of diabetic nephropathy. Diabetic rats, injected with nicotinamide-streptozotocin, were treated orally for 12 weeks with either vehicle, dapagliflozin 2 mg/kg/day, irbesartan 30 mg/kg/day, or combination of both drugs; respectively. Biochemical analysis included blood glucose, HbA1c, urinary albumin excretion, creatinine clearance, TGF-β1, sRAGE, oxidative markers, and histopathological examination of kidneys. Treatment with dapagliflozin, irbesartan, and especially their combination, produced significant reduction in albuminuria, improved renal function parameters, increased sRAGE level and improved inflammatory and oxidative markers, together with amelioration of renal histopathological changes. Beside glycemic control, dapagliflozin produced higher sRAGE levels than irbesartan, suggesting that inhibition of AGE-RAGE axis is important in its renoprotective action. Combination of dapagliflozin and irbesartan produced more remarkable protective effects on renal function and structure, than use of either agent alone. It is concluded that, combination of SGLT2 inhibitor, dapagliflozin and ARB, irbesartan could offer more effective renal protection and represent a promising therapeutic option for management of diabetic nephropathy.

Oxidative Stress and NLRP3-Inflammasome Activity as Significant Drivers of Diabetic Cardiovascular Complications: Therapeutic Implications

It is now increasingly appreciated that inflammation is not limited to the control of pathogens by the host, but rather that sterile inflammation which occurs in the absence of viral or bacterial pathogens, accompanies numerous disease states, none more so than the complications that arise as a result of hyperglycaemia. Individuals with type 1 or type 2 diabetes mellitus (T1D, T2D) are at increased risk of developing cardiac and vascular complications. Glucose and blood pressure lowering therapies have not stopped the advance of these morbidities that often lead to fatal heart attacks and/or stroke. A unifying mechanism of hyperglycemia-induced cellular damage was initially proposed to link elevated blood glucose levels with oxidative stress and the dysregulation of metabolic pathways. Pre-clinical evidence has, in most cases, supported this notion. However, therapeutic strategies to lessen oxidative stress in clinical trials has not proved efficacious, most likely due to indiscriminate targeting by antioxidants such as vitamins. Recent evidence now suggests that oxidative stress is a major driver of inflammation and vice versa, with the latest findings suggesting not only a key role for inflammatory pathways underpinning metabolic and haemodynamic dysfunction in diabetes, but furthermore that these perturbations are driven by activation of the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome. This review will address these latest findings with an aim of highlighting the interconnectivity between oxidative stress, NLRP3 activation and inflammation as it pertains to cardiac and vascular injury sustained by diabetes. Current therapeutic strategies to lessen both oxidative stress and inflammation will be emphasized. This will be placed in the context of improving the burden of these diabetic complications.

The Sodium Glucose Cotransporter 2 Inhibitor Ipragliflozin Promotes Preferential Loss of Fat Mass in Non-obese Diabetic Goto-Kakizaki Rats

Sodium glucose cotransporter 2 (SGLT2) inhibitors improve hyperglycemia in patients with type 2 diabetes mellitus (T2DM) by increasing urinary glucose excretion. In addition to their antihyperglycemic effect, SGLT2 inhibitors also reduce body weight and fat mass in obese and overweight patients with T2DM. However, whether or not SGLT2 inhibitors similarly affect body composition of non-obese patients with T2DM remains unclear. In this study, we investigated the effect of the SGLT2 inhibitor ipragliflozin on body composition in a Goto-Kakizaki (GK) rat model of non-obese T2DM. GK rats were treated with ipragliflozin once daily for 9 weeks, starting at 23 weeks of age. Body composition was then analyzed using dual-energy X-ray absorptiometry. Treatment with ipragliflozin increased urinary glucose excretion, reduced hemoglobin A1c (HbA1c) levels and suppressed body weight gain as the dose increased. Body composition analysis revealed that body fat mass was lower in the ipragliflozin-treated groups than in the control group, while lean body mass and bone mineral contents were comparable between groups. Thus, an SGLT2 inhibitor ipragliflozin was found to promote preferential loss of fat mass in a rat model of non-obese T2DM. Ipragliflozin might also promote preferential loss of fat in non-obese patients with T2DM.

Canagliflozin, an SGLT2 inhibitor, attenuates the development of hepatocellular carcinoma in a mouse model of human NASH

Sodium glucose cotransporter 2 (SGLT2) inhibitors, an antidiabetic drug, promotes urinary excretion of glucose by blocking its reabsorption in the renal proximal tubules. It is unclear whether SGLT2 inhibition could attenuate nonalcoholic steatohepatitis (NASH) and NASH-associated hepatocellular carcinoma. We examined the preventive effects of an SGLT2 inhibitor canagliflozin (CANA) in Western diet (WD)-fed melanocortin 4 receptor-deficient (MC4R-KO) mice, a mouse model of human NASH. An eight-week CANA treatment attenuated hepatic steatosis in WD-fed MC4R-KO mice, with increased epididymal fat mass without inflammatory changes. CANA treatment for 20 weeks inhibited the development of hepatic fibrosis in WD-fed MC4R-KO mice. After one year of CANA treatment, the number of liver tumors was significantly reduced in WD-fed MC4R-KO mice. In adipose tissue, CANA suppressed the ratio of oxidative to reduced forms of glutathiones (GSSG/GSH) in WD-fed MC4R-KO mice. Treatment with GSH significantly attenuated the H₂O₂-induced upregulation of genes related to NADPH oxidase in 3T3-L1 adipocytes, and that of Il6, Tgfb, and Pdgfb in RAW264.7 cells. This study provides evidence that SGLT2 inhibitors represent the unique class of drugs that can attenuate or delay the onset of NASH and eventually hepatocellular carcinoma, at least partly, through “healthy adipose expansion”.

Emerging roles of SGLT2 inhibitors in obesity and insulin resistance: Focus on fat browning and macrophage polarization

Obesity-associated low-grade inflammation underlies insulin resistance and associated metabolic comorbidities, such as type 2 diabetes (T2D) and nonalcoholic fatty liver disease. Excessive ectopic fat deposition in obesity causes disorders of energy homeostasis and low-grade chronic inflammation in metabolic tissues. In particular, obesity-induced recruitment and activation of adipose tissue macrophages play a key role in the pathogenesis of insulin resistance and T2D. Therefore, treatment options for energy metabolism and macrophage polarization in obese subjects are needed. Sodium-glucose cotransporter (SGLT) 2 inhibitors increase urinary glucose excretion by inhibiting renal glucose reabsorption, thereby having subsequent anti-hyperglycemic effects and reducing body weight. We recently reported that the SGLT2 inhibitor empagliflozin increases fat utilization and browning in white adipose tissue and attenuates obesity-induced inflammation and insulin resistance by activating M2 macrophages. Thus, this review focuses on the beneficial effects of empagliflozin in energy homeostasis and obesity-related inflammation and insulin resistance.

Effects of the SGLT2 inhibitor ipragliflozin on various diabetic symptoms and progression of overt nephropathy in type 2 diabetic mice

Diabetic nephropathy is the leading cause of end-stage renal disease and is associated with high-cardiovascular risk and significant morbidity and mortality. The recent development of sodium-glucose cotransporter (SGLT) 2 inhibitors offers a new antidiabetic therapy via enhanced glucose excretion; however, the beneficial effect of these drugs on the development of type 2 diabetic overt nephropathy is still largely unclear. We examined the therapeutic effects of the SGLT2 inhibitor ipragliflozin on various diabetic symptoms and the progression of nephropathy in uninephrectomized type 2 diabetic mice, which exhibit not only typical diabetic symptoms, such as impaired insulin secretion, glucose intolerance, hyperglycemia, and obesity, but also overt nephropathy with decline in renal function. Diabetes was induced by intraperitoneal administration of nicotinamide (1000 mg/kg) and streptozotocin (150 mg/kg) to uninephrectomized high-fat diet-fed mice. Ipragliflozin (0.1-3 mg/kg) was orally administered to diabetic mice once daily for 4 weeks. Repeated administration of ipragliflozin improved diabetic symptoms, such as hyperglycemia and insulin resistance, via an increase in urinary glucose excretion. In addition, ipragliflozin attenuated albuminuria/proteinuria and the decline in renal function, and improved renal injury, including glomerulosclerosis and interstitial fibrosis. Our results demonstrate that ipragliflozin improves various diabetic symptoms and delays development of diabetic nephropathy. Therefore, SGLT2 inhibitors could constitute a novel therapeutic target for the treatment of type 2 diabetes with overt nephropathy.

SGLT2 Inhibitors and Mechanisms of Hypertension

PURPOSE OF REVIEW

We sought to review currently available data on the safety and efficacy of sodium-glucose cotransporter 2 (SGLT2) inhibitors in type 2 diabetes mellitus patients with hypertension.

RECENT FINDINGS

Inhibition of SGLT2 in the renal proximal tubule results in increased urinary glucose excretion and modest improvements of hemoglobin A1C. Treatment with any of the three currently FDA-approved SGLT2 inhibitors (canagliflozin, dapagliflozin, empagliflozin) results in sustained systolic and diastolic blood pressure reduction, in part via minimal natriuresis and possible reductions in sympathetic tone. Recent randomized clinical trials in high cardiovascular risk patients with type 2 diabetes suggest that the unique effects of SGLT2 inhibitors on blood pressure and body weight may translate into reduced cardiovascular events and slowed kidney disease progression. However, concerns about volume depletion and acute kidney injury have been raised. SGLT2 inhibitors are viable second-line glucose-lowering agents for people with type 2 diabetes with high cardiovascular risk.

SGLT-2 Inhibition with Dapagliflozin Reduces the Activation of the Nlrp3/ASC Inflammasome and Attenuates the Development of Diabetic Cardiomyopathy in Mice with Type 2 Diabetes. Further Augmentation of the Effects with Saxagliptin, a DPP4 Inhibitor

PURPOSE

We assessed whether (1) dapagliflozin (Dapa, an SGLT2-inhibitor) attenuates the deterioration of heart function Nlrp3 and inflammasome activation in diabetic mice. (2) The effects can be augmented with saxagliptin (Saxa), a DDP4-inhibitor. (3) Dapa effect is possibly SGLT2-independent on cardiofibroblasts in vitro.

METHODS

Type 2 diabetic (BTBR ob/ob) and wild-type (WT) mice received vehicle, Dapa, or Dapa+Saxa for 8 weeks. Glucose tolerance test and echocardiogram were performed. Cardiofibroblasts from WT and BTBR hearts were incubated with Dapa and exposed to LPS.

RESULTS

Left ventricular ejection fraction (LVEF) was 81 ± 1% in the WT and 53 ± 1% in the T2D-cont mice. Dapa and Dapa+Saxa improved LVEF to 68 ± 1 and 74.6 ± 1% in the BTBR mice (p < 0.001). The mRNA levels of NALP3, ASC, IL-1β, IL-6, caspase-1, and TNFα were significantly higher in the BTBR compared to the WT hearts; and Dapa and Dapa+Saxa significantly attenuated these levels. Likewise, protein levels of NLRP3, TNFα, and caspase-1 were higher in the BTBR compared to the WT hearts and Dapa, and to a greater extent Dapa+Saxa, attenuated the increase in the BTBR mice. Collagen-1 and collagen-3 mRNA levels significantly increased in the BTBR mice and these increases were attenuated by Dapa and Dapa+Saxa. P-AMPK/total-AMPK ratio was significantly lower in the BTBR mice than in the WT mice. Dapa and Dapa+Saxa equally increased the ratio in the BTBR mice. This in vitro study showed that NALP3, ASC, IL-1β, and caspase-1 mRNA levels were higher in the BTBR cardiofibroblasts and attenuated with Dapa. The effect was AMPK-dependent and SGLT1-independent.

CONCLUSIONS

Dapa attenuated the activation of the inflammasome, fibrosis, and deterioration of LVEF in BTBR mice. The anti-inflammatory, anti-fibrotic effects are likely SGLT2- and glucose-lowering-independent, as they were replicated in the in vitro model. The effects on remodeling were augmented when Saxa was added to Dapa. Yet, adding Saxa to Dapa did not result in a greater effect on myocardial fibrosis and collagen levels.

Combining SGLT2 Inhibition With a Thiazolidinedione Additively Attenuate the Very Early Phase of Diabetic Nephropathy Progression in Type 2 Diabetes Mellitus

Although both sodium glucose co-transporter 2 inhibition by dapagliflozin and thiazolidinedione, pioglitazone have glucose-lowering and anti-inflammatory effects, the therapeutic efficacy of their combination on diabetic nephropathy has not been investigated. 9-week-old male db/db mice were randomly assigned to 4 groups and administrated with (1) vehicle, (2) dapagliflozin, (3) pioglitazone, or (4) dapagliflozin and pioglitazone combination. Human proximal tubule (HK-2) cells were treated with glucose or palmitate acid in the presence of medium, dapagliflozin, pioglitazone, or both. Glomerular tuft area and mesangial expansion of the kidney more reduced in the combination group compared to control and single therapy groups. Podocyte foot process width and glomerular basement membrane thickness decreased regardless of treatment, while the combination group showed the slowest renal hypertrophy progression (P < 0.05). The combination treatment decreased MCP-1, type I and IV collagen expression in the renal cortex. Only the combination treatment decreased the expression of angiotensinogen, IL-6, and TGF-β while it enhanced HK-2 cell survival (all P < 0.05). In conclusion, dapagliflozin and pioglitazone preserved renal function, and combination therapy showed the greatest benefit. These findings suggest that the combination therapy of dapagliflozin with pioglitazone is more effective than the single therapy for preventing the progression of nephropathy in patients with type 2 diabetes.

Major adverse cardiovascular event reduction with GLP-1 and SGLT2 agents: evidence and clinical potential

Treatment of patients with type 2 diabetes is directed against treating symptoms of hyperglycemia, minimizing the risk of hypoglycemia, and the risk of microvascular and macrovascular complications. The majority of patients with type 2 diabetes die from cardiovascular or cerebrovascular disease. Future therapies should therefore focus on reducing cardiovascular morbidity in this high-risk population. Glucagon-like peptide-1 receptor agonists (GLP-1RA) and sodium-glucose co-transporter 2 inhibitors (SGLT2-i) are two drug classes with proven antihyperglycemic effect in type 2 diabetes. However, these drugs seem to have other effects such as weight reduction, low risk of hypoglycemia, and blood pressure reduction. Emerging evidence suggests pleiotropic effects, which potentially could be important in reducing cardiovascular risk. Prompted by regulatory authorities demanding cardiovascular outcome trials (CVOTs) assessing the cardiovascular safety of new antihyperglycemic drug candidates, many CVOTs are ongoing and a few of these are finalized. Somewhat surprising recent CVOTs in both drug classes have shown promising data on cardiovascular morbidity and mortality in patients with a very high risk of cardiovascular events. It is uncertain whether this is a class effect of the two drug classes, and it is yet unproven whether long-term cardiovascular benefits of these drugs can be extrapolated to populations at lower risk of cardiovascular disease. The aim of the present review is to give an overview of our current knowledge of the GLP-1RA and SGLT2-i classes, with specific focus on mechanisms of action, effects on cardiovascular risk factors and cardiovascular morbidity and mortality from the CVOTs presently available. The clinical potential of these data is discussed.

Cardiovascular effects of sodium glucose cotransporter 2 inhibitors

As the first cardiovascular (CV) outcome trial of a glucose-lowering agent to demonstrate a reduction in the risk of CV events in patients with type 2 diabetes mellitus (T2DM), the EMPAgliflozin Removal of Excess Glucose: Cardiovascular OUTCOME Event Trial in Type 2 Diabetes Mellitus Patients (EMPA-REG OUTCOME^®) trial, which investigated the sodium glucose cotransporter 2 (SGLT2) inhibitor empagliflozin, has generated great interest among health care professionals. CV outcomes data for another SGLT2 inhibitor, canagliflozin, have been published recently in the CANagliflozin CardioVascular Assessment Study (CANVAS) Program, as have CV data from the retrospective real-world study Comparative Effectiveness of Cardiovascular Outcomes in New Users of Sodium-Glucose Cotransporter-2 Inhibitors (CVD-REAL), which compared SGLT2 inhibitors with other classes of glucose-lowering drugs. This review discusses the results of these three studies and, with a focus on EMPA-REG OUTCOME, examines the possible mechanisms by which SGLT2 inhibitors may reduce CV risk in patients with T2DM.

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.

Dapagliflozin slows the progression of the renal and liver fibrosis associated with type 2 diabetes

Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a new class of antidiabetic oral agents indicating promising effects on cardiovascular and renal end points. However, the renoprotective effects of SGLT2 inhibitors are not fully understood. Also, metabolic effects of SGLT2 inhibition on other organ systems, such as effects on hepatic steatosis, are not fully understood. This study sought to address these questions by treating 18-wk-old uninephrectomized db/db mice with the selective SGLT2 inhibitor dapagliflozin. Untreated db/db mice developed progressive albuminuria, glomerular mesangial matrix expansion, and fatty liver associated with increased renal expression of TGFβ1, PAI-1, type IV collagen and fibronectin, and liver deposition of fibronectin, type I and III collagen, and laminin. Treatment with dapagliflozin (1 mg·kg^-1·day^-1) via gel diet from 18 to 22 wk of age not only reduced blood glucose (371.14 ± 55.02 mg/dl in treated db/db vs. 573.53 ± 21.73 mg/dl in untreated db/db, P < 0.05) and Hb A_1c levels (9.47 ± 0.79% in treated db/db vs. 12.1 ± 0.73% in untreated db/db, P < 0.05) but also ameliorated the increases in albuminuria and markers of glomerulosclerosis and liver injury seen in untreated db/db mice. Furthermore, both renal expressions of NF-kB p65, MCP-1, Nox4, Nox2, and p47phox and urine TBARS levels and liver productions of myeloperoxidase and reactive oxygen species, the markers of tissue inflammation and oxidative stress, were increased in untreated db/db mice, which were reduced by dapagliflozin administration. These results demonstrate that dapagliflozin not only improves hyperglycemia but also slows the progression of diabetes-associated glomerulosclerosis and liver fibrosis by improving hyperglycemia-induced tissue inflammation and oxidative stress.

Comparison of Ipragliflozin and Pioglitazone Effects on Nonalcoholic Fatty Liver Disease in Patients With Type 2 Diabetes: A Randomized, 24-Week, Open-Label, Active-Controlled Trial

OBJECTIVE

To compare the efficacy of ipragliflozin versus pioglitazone in patients with type 2 diabetes complicated by nonalcoholic fatty liver disease (NAFLD).

RESEARCH DESIGN AND METHODS

In this open-label, randomized, active-controlled trial, we randomly assigned 66 patients with type 2 diabetes and NAFLD to receive ipragliflozin 50 mg (n = 32) or pioglitazone 15-30 mg (n = 34) orally once daily. The primary outcome was a change from baseline in the liver-to-spleen attenuation ratio (L/S ratio) on computed tomography at week 24.

RESULTS

At week 24, the mean ± SD L/S ratio had increased by 0.22 (from 0.80 ± 0.24 to 1.00 ± 0.18) in the ipragliflozin group and 0.21 (from 0.78 ± 0.26 to 0.98 ± 0.16) in the pioglitazone group (P = 0.90). Serum aspartate and alanine aminotransferase levels, HbA_1c, and fasting plasma glucose were similarly reduced in the two treatment groups. Nevertheless, body weight and visceral fat area showed significant reductions only in the ipragliflozin group compared with the pioglitazone group (P < 0.0001 and P = 0.0013, respectively). There were no serious adverse events in either group.

CONCLUSIONS

Compared with pioglitazone, ipragliflozin exerts equally beneficial effects on NAFLD and glycemic control during the treatment of patients with type 2 diabetes complicated by NAFLD. Furthermore, ipragliflozin significantly reduced body weight and abdominal fat area.

Responses of renal hemodynamics and tubular functions to acute sodium-glucose cotransporter 2 inhibitor administration in non-diabetic anesthetized rats

The aim of this study is to examine the effects of acute administration of luseogliflozin, the sodium–glucose cotransporter 2 (SGLT2) inhibitor, on renal hemodynamics and tubular functions in anesthetized non-diabetic Sprague Dawley (SD) rats and 5/6 nephrectomized (Nx) SD rats. Renal blood flow (RBF), mean arterial pressure (MAP), and heart rate (HR) were continuously measured and urine was collected directly from the left ureter. Intraperitoneal injection of luseogliflozin (0.9 mg kg⁻¹) did not change MAP, HR, RBF, or creatinine clearance (CrCl) in SD rats (n = 7). Luseogliflozin significantly increased urine volume, which was associated with significantly increased urinary glucose excretion rates (P < 0.001). Similarly, luseogliflozin significantly increased urinary sodium excretion (from 0.07 ± 0.01 µmol min⁻¹ at baseline to 0.76 ± 0.08 µmol min⁻¹ at 120 min; P < 0.001). Furthermore, luseogliflozin resulted in significantly increased urinary pH (P < 0.001) and decreased urinary osmolality and urea concentration (P < 0.001) in SD rats. Similarly, in Nx SD rats (n = 5–6), luseogliflozin significantly increased urine volume and urinary glucose excretion (P < 0.001) without altering MAP, HR, RBF, or CrCl. Luseogliflozin did not elicit any significant effects on the other urinary parameters in Nx SD rats. These data indicate that SGLT2 inhibitor elicits direct tubular effects in non-diabetic rats with normal renal functions.

The potential role and rationale for treatment of heart failure with sodium-glucose co-transporter 2 inhibitors

Heart failure (HF) and type 2 diabetes mellitus (T2DM) are both growing public health concerns contributing to major medical and economic burdens to society. T2DM increases the risk of HF, frequently occurs concomitantly with HF, and worsens the prognosis of HF. Several anti-hyperglycaemic medications have been associated with a concern for worse HF outcomes. More recently, the results of the EMPA-REG OUTCOME trial showed that the sodium-glucose co-transporter 2 (SGLT2) inhibitor empagliflozin was associated with a pronounced and precocious 38% reduction in cardiovascular mortality in subjects with T2DM and established cardiovascular disease [Correction added on 8 September 2017, after first online publication: "32%" in the previous sentence was corrected to "38%"]. These benefits were more related to a reduction in incident HF events rather than to ischaemic vascular endpoints. Several mechanisms have been put forward to explain these benefits, which also raise the possibility of using these drugs as therapies not only in the prevention of HF, but also for the treatment of patients with established HF regardless of the presence or absence of diabetes. Several large trials are currently exploring this postulate.