SGLT2 Inhibitors and the Diabetic Kidney

Effects of the SGLT-2 Inhibitor Empagliflozin on Renal Tissue Oxygenation in Non-Diabetic Subjects: A Randomized, Double-Blind, Placebo-Controlled Study Protocol

INTRODUCTION

Empagliflozin is an SGLT-2 inhibitor (SGLT-2i) which belongs to a new class of hypoglycemic drugs with the unique property of decreasing blood glucose independently from insulin, through an increase in glycosuria. In addition to decreasing cardiovascular morbidity and mortality, empagliflozin has nephroprotective properties in high cardiovascular risk patients with type 2 diabetes. Decreased hyperfiltration and shifting towards more favorable renal fuel energetics with improved renal oxygenation may explain some of these properties. With this study, we propose to explore the effects of empagliflozin on renal tissue oxygenation using blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI).

METHODS

This is a double-blind, randomized, placebo-controlled study examining the acute and chronic renal effects of empagliflozin 10 mg. The primary outcome is the effects of empagliflozin on renal tissue oxygenation as measured by BOLD-MRI. The secondary outcomes include the effects of empagliflozin on tubular function, 24 h blood pressure control, and the influence of body mass index (BMI) on the renal response to empagliflozin. Fifteen normal weight, 15 overweight, and 15 obese non-diabetic subjects (men and women) will be recruited. Each participant will undergo 24 h urine collections and blood pressure measurements on day - 1, followed by an investigation day at the study center with blood and urine sampling and renal BOLD-MRI measurements before and 180 min after the administration of 10 mg empagliflozin or placebo. This sequence of measurements will be repeated after 1 month of a daily empagliflozin or placebo intake. To investigate renal oxygenation, the renal cortical and medullary R2*, as a marker of oxygenation, will be assessed by BOLD-MRI under standardized hydration conditions: the higher R2*, the lower oxygenation.

CONCLUSION

SGLT-2 inhibitors have a profound effect on renal physiology. This is an important study that will explore for the first time whether inhibiting SGLT-2 with empagliflozin in healthy volunteers affects renal tissue oxygenation as determined by BOLD-MRI.

FUNDING

Boehringer Ingelheim Pharma GmbH & Co.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT03093103.

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.

Cardiovascular Effects of New Oral Glucose-Lowering Agents: DPP-4 and SGLT-2 Inhibitors

Cardiovascular disease (CVD) is a major challenge in the management of type 2 diabetes mellitus. Glucose-lowering agents that reduce the risk of major cardiovascular events would be considered a major advance, as recently reported with liraglutide and semaglutide, 2 glucagon-like peptide-1 receptor agonists, and with empagliflozin and canagliflozin, 2 SGLT-2 (sodium-glucose cotransporter type 2) inhibitors, but not with DPP-4 (dipeptidyl peptidase-4) inhibitors. The present review is devoted to CV effects of new oral glucose-lowering agents. DPP-4 inhibitors (gliptins) showed some positive cardiac and vascular effects in preliminary studies, and initial data from phase 2 to 3 clinical trials suggested a reduction in major cardiovascular events. However, subsequent CV outcome trials with alogliptin, saxagliptin, and sitagliptin showed noninferiority but failed to demonstrate any superiority compared with placebo in patients with type 2 diabetes mellitus and high CV risk. An unexpected higher risk of hospitalization for heart failure was reported with saxagliptin. SGLT-2 inhibitors (gliflozins) promote glucosuria, thus reducing glucose toxicity and body weight, and enhance natriuresis, thus lowering blood pressure. Two CV outcome trials in type 2 diabetes mellitus patients mainly in secondary prevention showed remarkable positive results. Empagliflozin in EMPA-REG-OUTCOME (EMPAgliflozin Cardiovascular OUTCOME Events in Type 2 Diabetes Mellitus Patients) reduced major cardiovascular events, CV mortality, all-cause mortality, and hospitalization for heart failure. In CANVAS (Canagliflozin Cardiovascular Assessment Study), the reduction in CV mortality with canagliflozin failed to reach statistical significance despite a similar reduction in major cardiovascular events. The underlying protective mechanisms of SGLT-2 inhibitors remain unknown and both hemodynamic and metabolic explanations have been proposed. CVD-REAL studies (Comparative Effectiveness of Cardiovascular Outcomes in New Users of Sodium-Glucose Cotransporter-2 Inhibitors; with the limitation of an observational approach) suggested that these favorable results may be considered as a class effect shared by all SGLT-2 inhibitors (including dapagliflozin) and be extrapolated to a larger population of patients with type 2 diabetes mellitus in primary prevention. Ongoing CV outcome trials with other DPP-4 (linagliptin) and SGLT-2 (dapagliflozin, ertugliflozin) inhibitors should provide additional information about CV effects of both pharmacological classes.

A Low-Protein Diet for Diabetic Kidney Disease: Its Effect and Molecular Mechanism, an Approach from Animal Studies

A low-protein diet (LPD) can be expected to retard renal function decline in advanced stages of chronic kidney disease (CKD), including diabetic kidney disease (DKD), and is recommended in a clinical setting. Regarding the molecular mechanisms of an LPD against DKD, previous animal studies have shown that an LPD exerts reno-protection through mainly the improvement of glomerular hyperfiltration/hypertension due to the reduction of intraglomerular pressure. On the other hand, we have demonstrated that an LPD, particularly a very-LPD (VLPD), improved tubulo-interstitial damage, inflammation and fibrosis, through the restoration of autophagy via the reduction of a mammalian target of rapamycin complex 1 (mTORC1) activity in type 2 diabetes and obesity animal models. Thus, based on animal studies, a VLPD may show a more beneficial effect against advanced DKD. Previous clinical reports have also shown that a VLPD, not a moderate LPD, slows the progression of renal dysfunction in patients with chronic glomerular nephritis. However, there is insufficient clinical data regarding the beneficial effects of a VLPD against DKD. Additionally, the patients with CKD, including DKD, are a high-risk group for malnutrition, such as protein–energy wasting (PEW), sarcopenia, and frailty. Therefore, an LPD, including a VLPD, should be prescribed to patients when the benefits of an LPD outweigh the risks, upon consideration of adherence, age, and nutritional status. As the future predicts, the development of a VLPD replacement therapy without malnutrition may be expected for reno-protection against the advanced stages of DKD, through the regulation of mTORC1 activity and adequate autophagy induction. However, further studies to elucidate detailed mechanisms by which a VLPD exerts reno-protection are necessary.

Renal outcomes with sodium glucose cotransporter 2 (SGLT2) inhibitor, dapagliflozin, in obese insulin-resistant model

A growing body of evidence indicates that obesity and insulin resistance contribute to the progression of renal disease. This study was performed to determine the effects of dapagliflozin, a novel sodium glucose cotransporter 2 (SGLT2) inhibitor, on renal and renal organic anion transporter 3 (Oat3) functions in high-fat diet fed rats, a model of obese insulin-resistance. Twenty-four male Wistar rats were divided into two groups, and received either a normal diet (ND) (n = 6) or a high-fat diet (HFD) (n = 18) for 16 weeks. At week 17, the HFD-fed rats were subdivided into three subgroups (n = 6/subgroup) and received either a vehicle (HFD), dapagliflozin (HFDAP; 1.0 mg/kg/day) or metformin (HFMET; 30 mg/kg/day), by oral gavage for four weeks. Metabolic parameters, renal function, renal Oat3 function, renal oxidative stress, and renal morphology were determined. The results showed that obese insulin-resistant rats induced by HFD feeding had impaired renal function and renal Oat3 function together with increased renal oxidative injury. Dapagliflozin or metformin treatment decreased insulin resistance, hypercholesterolemia, creatinine clearance and renal oxidative stress leading to improved renal function. However, dapagliflozin treatment decreased blood pressure, serum creatinine, urinary microalbumin and increased glucose excretions, and showed a greater ability to ameliorate impaired renal insulin signaling and glomerular barrier damage than metformin. These data suggest that dapagliflozin had greater efficacy than metformin for attenuating renal dysfunction and improving renal Oat3 function, at least in part by reducing renal oxidative stress and modulating renal insulin signaling pathways, and hence ameliorating renal injury.

Efficacy and safety of the addition of ertugliflozin in patients with type 2 diabetes mellitus inadequately controlled with metformin and sitagliptin: The VERTIS SITA2 placebo-controlled randomized study

AIMS

To assess ertugliflozin in patients with type 2 diabetes who are inadequately controlled by metformin and sitagliptin.

MATERIALS AND METHODS

In this double-blind randomized study (Clinicaltrials.gov NCT02036515), patients (glycated haemoglobin [HbA1c] 7.0% to 10.5% [53-91 mmol/mol] receiving metformin ≥1500 mg/d and sitagliptin 100 mg/d; estimated glomerular filtration rate [eGFR] ≥60 mL/min/1.73 m2 ) were randomized to ertugliflozin 5 mg once-daily, 15 mg once-daily or placebo. The primary efficacy endpoint was change from baseline in HbA1c at Week 26; treatment was continued until Week 52.

RESULTS

A total of 464 patients were randomized (mean baseline HbA1c, 8.0% [64.3 mmol/mol]; eGFR, 87.9 mL/min/1.73 m2 ). After 26 weeks, placebo-adjusted least squares (LS) mean changes in HbA1c from baseline were -0.7% (-7.5 mmol/mol) and -0.8% (-8.3 mmol/mol) for ertugliflozin 5 and 15 mg, respectively (both P < .001); 17.0%, 32.1% and 39.9% of patients receiving placebo, ertugliflozin 5 mg or ertugliflozin 15 mg, respectively, had HbA1c <7.0% (53 mmol/mol). Significant reductions in fasting plasma glucose, body weight (BW) and systolic blood pressure (SBP) were observed with ertugliflozin relative to placebo. The positive effects of ertugliflozin on glycaemic control, BW and SBP were maintained through Week 52. A higher incidence of genital mycotic infections was observed in male and female patients receiving ertugliflozin (3.7%-14.1%) vs placebo (0%-1.9%) through Week 52. The incidence of urinary tract infections, symptomatic hypoglycaemia and hypovolaemia adverse events were not meaningfully different across groups.

CONCLUSIONS

Ertugliflozin added to metformin and sitagliptin was well-tolerated, and provided clinically meaningful, durable glycaemic control, BW and SBP reductions vs placebo over 52 weeks.

SGLT2 inhibitors with cardiovascular benefits: Transforming clinical care in Type 2 diabetes mellitus

Cardiovascular risk reduction in individuals with Type 2 diabetes mellitus (T2DM) is a key part of clinical management. Sodium-glucose co-transporter (SGLT2) inhibitors improve glycaemic control, reduce body weight and decrease blood pressure. In addition, the SGLT2 inhibitors empagliflozin and canagliflozin reduced the risk of composite cardiovascular events in high-risk individuals with T2DM in the EMPA-REG OUTCOME trial and the CANVAS Program, respectively. Empagliflozin also reduced cardiovascular deaths and improved renal outcomes. This class of agents should be considered in people with established cardiovascular disease, usually in combination with other glucose lowering medications, when satisfactory glycaemic control has not been achieved. The dose of insulin or sulfonylureas may need to be lowered when used with SGLT2 inhibitors, to reduce the risk of hypoglycaemia. Genitourinary infections can occur with SGLT2 inhibitors in a small proportion of people. In people with osteoporosis or prior amputation, it may be prudent to use empagliflozin rather than canagliflozin, based on the increased risk for bone fractures and amputations observed with canagliflozin in the CANVAS Program. SGLT2 inhibitors have the potential to transform the clinical care of persons with T2DM by not only improving glycaemic control but also reducing blood pressure, body weight and diabetes-related end-organ complications.

Ertugliflozin in Patients with Stage 3 Chronic Kidney Disease and Type 2 Diabetes Mellitus: The VERTIS RENAL Randomized Study

INTRODUCTION

Ertugliflozin is a sodium-glucose cotransporter 2 inhibitor in development for type 2 diabetes mellitus (T2DM). The safety and efficacy of ertugliflozin were evaluated over 52 weeks in patients with chronic kidney disease (CKD).

METHODS

In this double-blind randomized study (NCT01986855), patients with glycated hemoglobin (A1C) 7.0-10.5% and stage 3 CKD [estimated glomerular filtration rate (eGFR) ≥ 30 to < 60 mL/min/1.73 m²] who were undergoing treatment with standard diabetes therapy (or therapies) including insulin and/or sulfonylureas were randomized to once-daily ertugliflozin 5 mg, 15 mg, or placebo. Patients on metformin underwent a pre-randomization ≥ 10-week wash-off period. The primary endpoint was change from baseline in A1C at week 26 in the overall cohort. Secondary efficacy endpoints were assessed in the stage 3A CKD cohort (eGFR ≥ 45 to < 60 mL/min/1.73 m²) at weeks 26 and 52. Safety was assessed in the overall cohort.

RESULTS

468 patients were randomized (baseline mean A1C 8.2%). At week 26, reductions from baseline in A1C were observed across groups in the overall cohort [least squares mean changes (95% confidence interval) - 0.3% (- 0.4, - 0.1), - 0.3% (- 0.4, - 0.1), and - 0.4% (- 0.6, - 0.3) for placebo and for ertugliflozin 5 mg and 15 mg, respectively]. Prohibited use of metformin was identified in ~ 17% of patients and impacted evaluation of the primary endpoint. Greater reductions from baseline in body weight, fasting plasma glucose, and systolic blood pressure were observed with ertugliflozin versus placebo at week 26 (stage 3A CKD cohort). The incidences of urinary tract infections, genital mycotic infections, and hypoglycemia adverse events were not meaningfully different between groups. The incidence of hypovolemia-related adverse events was higher with ertugliflozin relative to placebo.

CONCLUSION

Although surreptitious metformin use impacted the primary analysis, reductions in blood glucose and body weight were observed with ertugliflozin in patients with T2DM and stage 3 CKD; ertugliflozin had an acceptable safety profile.

FUNDING

Merck Sharp & Dohme Corp. a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA and Pfizer Inc.

TRIAL REGISTRATION

Clinicaltrials.gov identifier NCT01986855.

Ertugliflozin and Sitagliptin Co-initiation in Patients with Type 2 Diabetes: The VERTIS SITA Randomized Study

INTRODUCTION

Ertugliflozin is an oral sodium-glucose cotransporter 2 inhibitor that is being developed to treat type 2 diabetes mellitus (T2DM). This study assessed the efficacy and safety of co-initiation of ertugliflozin and sitagliptin compared with placebo in patients with T2DM inadequately controlled on diet and exercise.

METHODS

In this phase III, randomized, double-blind, multicenter, placebo-controlled 26-week study (NCT02226003), patients with T2DM and glycated hemoglobin (HbA1c) 8.0-10.5% on diet/exercise were randomized 1:1:1 to ertugliflozin 5 mg once daily (QD) and sitagliptin 100 mg QD (E5/S100), ertugliflozin 15 mg QD and sitagliptin 100 mg QD (E15/S100), or placebo. The primary efficacy endpoint was the change from baseline in HbA1c at week 26.

RESULTS

The mean baseline HbA1c of the randomized patients (n = 291) was 8.9%. At week 26, both ertugliflozin/sitagliptin treatments provided significant reductions from baseline in HbA1c compared with placebo [least squares mean HbA1c change (95% confidence intervals) from baseline was - 0.4% (- 0.7, - 0.2), - 1.6% (- 1.8, - 1.4), and - 1.7% (- 1.9, - 1.5) for placebo, E5/S100, and E15/S100, respectively]. At week 26, 8.3%, 35.7%, and 31.3% of patients receiving placebo, E5/S100, and E15/S100, respectively, had HbA1c < 7.0%. Significant reductions in fasting plasma glucose, 2-h post-prandial glucose, body weight, and systolic blood pressure were observed with both ertugliflozin/sitagliptin groups compared with placebo. The incidence of adverse events (AEs) was similar across the groups. The incidences of the pre-specified AEs of urinary tract infection, genital mycotic infection, symptomatic hypoglycemia, and hypovolemia were low and not meaningfully different across groups.

CONCLUSION

Co-initiation of ertugliflozin with sitagliptin in patients with T2DM inadequately controlled on diet and exercise provided a clinically meaningful improvement in glycemic control over 26 weeks.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov NCT02226003.

Pharmacotherapy of type 2 diabetes: An update

Type 2 diabetes (T2DM) is a leading cause of morbidity and mortality worldwide and a major economic burden. The prevalence of T2DM is rising, suggesting more effective prevention and treatment strategies are necessary. The aim of this narrative review is to summarize the pharmacologic treatment options available for patients with T2DM. Each therapeutic class is presented in detail, outlining medication effects, side effects, glycemic control, effect on weight, indications and contraindications, and use in selected populations (heart failure, renal insufficiency, obesity and the elderly). We also present representative cost for each antidiabetic category. Then, we provide an individualized guide for initiation and intensification of treatment and discuss the considerations and rationale for an individualized glycemic goal.

Mechanisms of Aerobic Exercise Impairment in Diabetes: A Narrative Review

The prevalence of diabetes in the United States and globally has been rapidly increasing over the last several decades. There are now estimated to be 30.3 million people in the United States and 422 million people worldwide with diabetes. Diabetes is associated with a greatly increased risk of cardiovascular mortality, which is the leading cause of death in adults with diabetes. While exercise training is a cornerstone of diabetes treatment, people with diabetes have well-described aerobic exercise impairments that may create an additional diabetes-specific barrier to adding regular exercise to their lifestyle. Physiologic mechanisms linked to exercise impairment in diabetes include insulin resistance, cardiac abnormalities, mitochondrial function, and the ability of the body to supply oxygen. In this paper, we highlight the abnormalities of exercise in type 2 diabetes as well as potential therapeutic approaches.

Newer Perspectives of Mechanisms for Euglycemic Diabetic Ketoacidosis

Euglycemic diabetic ketoacidosis (EDKA) was considered a rare condition with its specific definition and precipitating factors. However, with the wide use of sodium glucose cotransporter 2 (SGLT-2) inhibitors, the newest class of antidiabetic agents, EDKA has come back into the spotlight. Relevant cases are increasingly being reported along with insights into the mechanism of EDKA. It seems increasingly clear that EDKA is more common than we used to believe. The SGLT-2 inhibitor-associated EDKA also indicates a necessary review of our previous understanding of "diabetic" ketoacidosis, since the SGLT-2 inhibitor predisposes patients to DKA in a "starvation" way. Actually, there are growing reports about starvation-induced ketoacidosis as well. The previously "exclusive" nomenclature and cognition of these entities need to be reexamined. That the hormonal interactions in DKA may differ from the severity of insulin deficiency also may have served in the scenario of EDKA. The SGLT-2 inhibitors are newly approved in China. The main purpose of this work is to have a better understanding of the situation and update our knowledge with a focus on the pathogenesis of EDKA.

Model-Based Evaluation of Proximal Sodium Reabsorption Through SGLT2 in Health and Diabetes and the Effect of Inhibition With Canagliflozin

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) reduce glucose levels in diabetes by inhibiting renal glucose reabsorption in the proximal tubule (PT), resulting in urinary glucose excretion. A recent large cardiovascular outcomes trial suggested that the SGLT2i empagliflozin may also decrease risk of renal dysfunction. Because sodium (Na) and glucose reabsorption are coupled through SGLT2, it is hypothesized that the renal benefits may be derived from lowering Na reabsorption in the PT, which would lead to favorable renal hemodynamic changes. However, the quantitative contribution of SGLT2 to PT Na reabsorption, as well as the differences between healthy and diabetic subjects, and the impact of SGLT2i on PT Na reabsorption are unknown. In this study we extended an existing mathematical model of glucose dynamics to account for renal glucose filtration and excretion. We utilized this model to quantify glucose and Na reabsorption through SGLT2 in healthy, controlled, and uncontrolled diabetes and following treatment with canagliflozin. In healthy, controlled diabetic, and uncontrolled diabetic states, Na reabsorption through SGLT2 was found to be 5.7%, 11.5%, and 13.7% of total renal Na reabsorption, and 7.1% to 9.5%, 14.4% to 19.2%, and 17.1% to 22.8% of sodium reabsorption in the PT alone. The model predicted that treatment of controlled diabetes with canagliflozin returns PT Na reabsorption through SGLT2 to normal levels. The degree of increased PT Na reabsorption due to SGLT2 is likely sufficient to drive pathologic changes in renal hemodynamics, and restoration of normal Na reabsorption through SGLT2 may contribute to beneficial renal effects of SGLT2 inhibition.

Renal outcomes with dipeptidyl peptidase-4 inhibitors

Dipeptidyl peptidase-4 inhibitors (DPP-4is) are increasingly being used in the management of type 2 diabetes (T2D). The present review summarizes the current knowledge of the effects of DPP-4is on renal outcomes by analyzing the experimental preclinical data, the effects of DPP-4is on urinary albumin-creatinine ratios (UACRs) and estimated glomerular filtration rates (eGFRs) from observational studies and clinical trials, and renal events (including kidney failure requiring renal replacement therapy) in recent large prospective cardiovascular outcome trials. Renal protection has been demonstrated in various animal models that have implicated different underlying mechanisms independent of glucose control, whereas prevention of new onset microalbuminuria and/or progression of albuminuria has been reported in some clinical studies, but with no significant effects on eGFR in most of them. The long-term clinical effects of DPP-4is on renal outcomes and the development of end-stage renal disease remain largely unknown and, thus, demand further investigations in prospective trials and long-term observational studies. In conclusion, despite promising results in animal models, data on surrogate biological markers of renal function and clinical renal outcomes remain rather scanty in patients with T2D, and mostly demonstrate the safety rather than true efficacy of DPP-4is.

Development of hyperkalemia following treatment with dapagliflozin (DAPA) in a patient with type 2 diabetes after bilateral adrenalectomy

Dapagliflozin (DAPA), a sodium-glucose co-transporter 2 (SGLT2) inhibitor, is known to have a beneficial diuretic effect, in addition to a glucose-lowering effect. Although SGLT2 inhibitor has been reported, the increase of hyperkalemia in patients treated with renin-angiotensin-aldosterone system (RAAS) inhibitors, their mechanism of action is unclear. We report the first case of a type 2 diabetes (T2DM) patient with potential mineralocorticoid deficiency who developed hyperkalemia after administration of DAPA. A 79-year-old woman underwent bilateral adrenalectomy for uncontrolled hypercortisolism due to an inoperable recurrence of Cushing's disease, and she was subsequently maintained on replacement therapy with glucocorticoid. She was diagnosed as having T2DM at 71 years of age and was treated with sitagliptin and miglitol. Since she presented with weight gain of about 5 kg over 6 months and her HbAlc level increased over 12%, 5 mg/day DAPA was added to her daily regimen. After the start of DAPA treatment, she developed hyperkalemia (6.5 mEq/L) with increased plasma renin activity of 53.1 ng/mL/h. She was diagnosed with aldosterone deficiency and started on fludrocortisone 0.1 mg daily, after which the hyperkalemia improved immediately. In this case, DAPA treatment could potentially increase the requirement for mineralocorticoid replacement, directly suggesting that the SGLT2 inhibition-induced natriuretic effect is accompanied by compensatory activation of the RAAS axis, which is essential to keep the serum potassium level within the normal range. Therefore, physicians should be careful about the development of hyperkalemia in patients when SGLT2 and RAAS inhibitors are used in combination.

Efficacy and safety of dapagliflozin in patients with inadequately controlled type 1 diabetes (DEPICT-1): 24 week results from a multicentre, double-blind, phase 3, randomised controlled trial

BACKGROUND

Dapagliflozin is a sodium-glucose cotransporter-2 inhibitor approved for the treatment of type 2 diabetes. We aimed to assess the efficacy and safety of dapagliflozin as an add-on to adjustable insulin in patients with inadequately controlled type 1 diabetes.

METHODS

DEPICT-1 was a double-blind, randomised, parallel-controlled, three-arm, phase 3, multicentre study done at 143 sites in 17 countries. Eligible patients were aged 18-75 years and had inadequately controlled type 1 diabetes (HbA_1c between ≥7·7% and ≤11·0% [≥61·0 mmol/mol and ≤97·0 mmol/mol]) and had been prescribed insulin for at least 12 months before enrolment. After an 8 week lead-in period to optimise diabetes management, patients were randomly assigned (1:1:1) using an interactive voice response system to dapagliflozin 5 mg or 10 mg once daily, given orally, or matched placebo. Randomisation was stratified by current use of continuous glucose monitoring, method of insulin administration, and baseline HbA_1c. The primary efficacy outcome was the change from baseline in HbA_1c after 24 weeks of treatment in the full analysis set, which consisted of all randomly assigned patients who received at least one dose of study drug. An additional 55 patients who were incorrectly and non-randomly allocated to only dapagliflozin treatment groups were included in the safety analysis set. This study was registered with ClinicalTrials.gov, number NCT02268214; data collection for the present analysis was completed on Jan 4, 2017, and a 28 week extension phase is ongoing.

FINDINGS

Between Nov 11, 2014, and April 16, 2016, 833 patients were assigned to treatment groups and included in safety analyses (dapagliflozin 5 mg [n=277] vs dapagliflozin 10 mg [n=296] vs placebo [n=260]; 778 of these patients were randomly assigned and included in the full analysis set for efficacy analyses (259 vs 259 vs 260; difference due to randomisation error affecting 55 patients). Mean baseline HbA_1c was 8·53% (70 mmol/mol; SD 0·67% [7·3 mmol/mol]). At week 24, both doses of dapagliflozin significantly reduced HbA_1c compared with placebo (mean difference from baseline to week 24 for dapagliflozin 5 mg vs placebo was -0·42% [95% CI -0·56 to -0·28; p<0·0001] and for dapagliflozin 10 mg vs placebo was -0·45% [-0·58 to -0·31; p<0·0001]). Among patients in the dapagliflozin 5 mg (n=277), dapagliflozin 10 mg (n=296), and placebo (n=260) groups, the most common adverse events were nasopharyngitis (38 [14%] vs 36 [12%] vs 39 [15%]), urinary tract infection (19 [7%] vs 11 [4%] vs 13 [5%]), upper respiratory tract infection (15 [5%] vs 15 [5%] vs 11 [4%]), and headache (12 [4%] vs 17 [6%] vs 11 [4%]). Hypoglycaemia occurred in 220 (79%), 235 (79%), and 207 (80%) patients in the dapagliflozin 5 mg, dapagliflozin 10 mg, and placebo groups, respectively; severe hypoglycaemia occurred in 21 (8%), 19 (6%), and 19 (7%) patients, respectively. Adjudicated definite diabetic ketoacidosis occurred in four (1%) patients in the dapagliflozin 5 mg group, five (2%) in the dapagliflozin 10 mg group, and three (1%) in the placebo group.

INTERPRETATION

Our results suggest that dapagliflozin is a promising adjunct treatment to insulin to improve glycaemic control in patients with inadequately controlled type 1 diabetes.

FUNDING

AstraZeneca and Bristol-Myers Squibb.

Effect of Empagliflozin on Tacrolimus-Induced Pancreas Islet Dysfunction and Renal Injury

An inhibitor of sodium glucose co-transporter type 2 (SGLT-2) is recommended in type 2 diabetes mellitus (DM) but its use is still undetermined in tacrolimus (TAC)-induced DM. We evaluated the effect of empagliflozin (Em) on TAC-induced pancreatic islet dysfunction and renal injury in an experimental model of TAC-induced DM and in vitro. TAC induced a twofold increase in SGLT-2 expression, while Em decreased SGLT-2 expression and further increased urinary glucose excretion compared to the TAC group. Em reduced hyperglycemia and increased plasma insulin level, pancreatic islet size, and glucose-stimulated insulin secretion compared to the TAC group. In kidney, Em alleviated TAC-induced renal dysfunction and decreased albumin excretion and histological injury compared with the TAC group. Increased oxidative stress and apoptotic cell death by TAC was remarkably decreased with Em in serum and pancreatic and renal tissues. In in vitro study, TAC decreased cell viability and increased reactive oxygen species (ROS) production in both insulin-secreting beta-cell derived (INS-1) and human kidney-2 (HK-2) cell lines. Addition of Em increased cell viability and decreased ROS production in HK-2 but not in INS-1 cell lines. This suggests that Em is effective in controlling TAC-induced hyperglycemia and has direct protective effect on TAC-induced renal injury.

Practical Approach to Initiating SGLT2 Inhibitors in Type 2 Diabetes

Sodium-glucose co-transporter 2 (SGLT2) inhibitors are an attractive novel therapeutic option for the treatment of type 2 diabetes. They block the reabsorption of filtered glucose in kidneys, mainly in proximal renal tubules, resulting in increased urinary glucose excretion and correction of the diabetes-related hyperglycemia. Beyond improving glucose control, SGLT2 inhibitors offer potential benefits by reducing body weight and blood pressure. On the basis of the efficacy demonstrated in clinical trials, SGLT2 inhibitors are recommended as second- or third-line agents for the management of patients with type 2 diabetes. Beneficial effects on kidney disease progression, cardiovascular and all-cause mortality, and hospitalization for heart failure have also been demonstrated with one SGLT2 inhibitor (empagliflozin). Potential adverse events resulting from their mechanism of action or related to concomitant therapies are reviewed. A treatment algorithm for the adjustment of concomitant therapies after initiating SGLT2 inhibitors is also proposed.

Interleukin-22 ameliorated renal injury and fibrosis in diabetic nephropathy through inhibition of NLRP3 inflammasome activation

Diabetic nephropathy (DN) is one of the most lethal complications of diabetes mellitus with metabolic disorders and chronic inflammation. Although the cytokine IL-22 was initially implicated in the pathogenesis of chronic inflammatory diseases, recent studies suggested that IL-22 could suppress inflammatory responses and alleviate tissue injury. Herein, we examined the role of IL-22 in DN. We found that serum levels of IL-22 were significantly downregulated in both patients and mice with DN. The expression of IL-22 was further decreased with the progression of DN, whereas IL-22 gene therapy significantly ameliorated renal injury and mesangial matrix expansion in mice with established nephropathy. IL-22 could also markedly reduce high glucose-induced and TGF-β1-induced overexpression of fibronectin and collagen IV in mouse renal glomerular mesangial cells in a dose-dependent manner, suggesting the potential role of IL-22 to inhibit the overproduction of ECM in vitro. Simultaneously, IL-22 gene therapy drastically alleviated renal fibrosis and proteinuria excretion in DN. In addition, IL-22 gene therapy markedly attenuated hyperglycemia and metabolic disorders in streptozotocin-induced experimental diabetic mice. Notably, IL-22 drastically reversed renal activation of NLRP3, cleavage of caspase-1, and the maturation of IL-1β in DN, suggesting unexpected anti-inflammatory function of IL-22 via suppressing the activation of NLRP3 inflammasome in vivo. Moreover, IL-22 markedly downregulated high glucose-induced activation of NLRP3 inflammasome in renal mesangial cells in a dose-dependent manner, indicating that the effects of IL-22 on NLRP3 inflammasome activation was independent of improved glycemic control. These results suggested that nephroprotection by IL-22 in DN was most likely associated with reduced activation of NLRP3 inflammasome. In conclusion, our finding demonstrated that IL-22 could exert favorable effects on DN via simultaneously alleviating systemic metabolic syndrome and downregulating renal NLRP3/caspase-1/IL-1β pathway, suggesting that IL-22 might have therapeutic potential for the treatment of DN.

Regulating Autophagy as a Therapeutic Target for Diabetic Nephropathy

PURPOSE OF REVIEW

Autophagy promotes cellular health in response to various cellular stresses and to changes in nutrient conditions. In this review, we focus on the role of autophagy in the pathogenesis of diabetic nephropathy and discuss the regulation of autophagy as a new therapeutic target for the suppression of diabetic nephropathy.

RECENT FINDINGS

Previous studies have indicated that autophagy deficiency or insufficiency in renal cells, including podocytes, mesangial cells, endothelial cells and tubular cells, contributes to the pathogenesis of diabetic nephropathy. Alterations in the nutrient-sensing pathways, including mammalian target of rapamycin complex1 (mTORC1), AMP-activated kinase (AMPK) and Sirt1, due to excess nutrition　in diabetes are implicated in the impairment of autophagy. Maintaining both basal and adaptive autophagy against cellular stress may protect the kidney from diabetes-induced cellular stresses. Therefore, the activation of autophagy through the modulation of nutrient-sensing pathways may be a new therapeutic option for the suppression of diabetic nephropathy.

Cardiovascular Protection by Sodium Glucose Cotransporter 2 Inhibitors: Potential Mechanisms

The mechanism of action of empagliflozin in reducing the risk of adverse cardiovascular outcomes vs placebo in patients with type 2 diabetes mellitus and a high risk of cardiovascular disease in the Empagliflozin Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients-Removing Excess Glucose (EMPA-REG OUTCOME) trial is currently unknown. An antiatherosclerotic effect is considered unlikely given the speed of the observed decrease in cardiovascular mortality. Hemodynamic effects, such as reductions in blood pressure and intravascular volume, and involving osmotic diuresis, may provide a more plausible explanation. Metabolic effects, such as cardiac fuel energetics, and hormonal effects, such as increased glucagon release, may also contribute to the results observed during EMPA-REG OUTCOME. This review discusses the main hypotheses suggested to date.

Euglycemic Diabetic Ketoacidosis With Prolonged Glucosuria Associated With the Sodium-Glucose Cotransporter-2 Canagliflozin

Sodium-glucose cotransporter-2 (SGLT2) inhibitors improve glycemic control by a reversible inhibition of the sodium-glucose cotransporters in the renal proximal tubules resulting in increased urinary glucose. This unique mechanism, independent of insulin secretion and beta cell function, has made this class of medication desirable in patients with type 2 diabetes. However in May 2015, the US Food and Drug Administration issued a safety warning pertaining to the development of diabetic ketoacidosis (DKA) with the use of SGLT2 inhibitors. DKA associated with SGLT2 inhibitors frequently develops in the absence of hyperglycemia, which makes the diagnosis more challenging. Due to the reversible inhibition of SGLT2 by this class of medication, a quick recovery of glucosuria after cessation of medication is expected. In this article, we present a case of a 50-year-old woman with type 2 diabetes who developed euglycemic DKA after initiating therapy with canagliflozin. This case of DKA associated with SGLT2 inhibitor use was unique due to her hypoglycemic presentation and persistent glucosuria. SGLT2 inhibitors such as canagliflozin may predispose patients not only to diabetic ketoacidosis but also to prolonged glucosuria.

Cardiovascular Protection by Sodium Glucose Cotransporter 2 Inhibitors: Potential Mechanisms

The mechanism of action of empagliflozin in reducing the risk of adverse cardiovascular outcomes vs placebo in patients with type 2 diabetes mellitus and a high risk of cardiovascular disease in the Empagliflozin Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients-Removing Excess Glucose (EMPA-REG OUTCOME) trial is currently unknown. An antiatherosclerotic effect is considered unlikely given the speed of the observed decrease in cardiovascular mortality. Hemodynamic effects, such as reductions in blood pressure and intravascular volume, and involving osmotic diuresis, may provide a more plausible explanation. Metabolic effects, such as cardiac fuel energetics, and hormonal effects, such as increased glucagon release, may also contribute to the results observed during EMPA-REG OUTCOME. This review discusses the main hypotheses suggested to date.

Therapeutic potential of tofogliflozin on nephrotic syndrome secondary to diabetic nephropathy

Diabetic nephropathy (DN) is a critical complication in patients with type 2 diabetes and regarded as a progressive disorder with a poor prognosis. The degree of albuminuria is associated closely with worse renal and cardiovascular outcomes. It is therefore important to achieve remission of proteinuria to avoid progression of DN and improve outcomes. Although a recent clinical trial demonstrated that a sodium glucose cotransporter 2 (SGLT2) inhibitor could improve cardiovascular and renal outcomes in cardiovascular high risk patients with type 2 diabetes, little is known whether SGLT2 inhibitors have favorably renal effects in patients with nephrotic syndrome associated with DN. Herein, we report a 54-year-old patient with refractory nephrotic syndrome accompanied by diabetic nephropathy. Tofogliflozin, a SGLT2 inhibitor, successfully increased urine volume, and reduced body weight, HbA1c, and urinary protein excretion (10.8 to 2.6 g/day) during 24 weeks. His severe edema also was diminished after administration of tofogliflozin. This case indicates that an SGLT2 inhibitor may be a useful choice in the treatment of patients with diabetic nephropathy and the nephrotic syndrome. <Learning objective: Little is known whether SGLT2 inhibitor can attenuate nephrotic-range of proteinuria in patients with diabetic nephropathy. The present case is the first to demonstrate that tofogliflozin markedly reduced urinary protein excretion, body weight, and relevant markers in patient with nephrotic syndrome secondary to diabetic nephropathy. Thus, it is suggested that SGLT2 inhibitor has a therapeutic potential to attenuate nephrotic syndrome-related symptoms and markers as well as glycemic control.>.

A consensus statement for the clinical use of the renal sodium-glucose co-transporter-2 inhibitor dapagliflozin in patients with type 2 diabetes mellitus

INTRODUCTION

The present review developed a clinical consensus based on a Delphi method on Dapagliflozin, a selective inhibitor of the renal sodium-glucose co-transporter-2 (SGLT2-I) in the treatment of patients with Type 2 diabetes mellitus. Areas covered: Panel members, using a 5-point scale, were asked to rate 9 statements on pharmakodinamic, mode of action on glycaemic and extra-glycaemic effects, and safety of dapaglifozin, Members also aimed to identify the patient most susceptible to the treatment with dapagliflozin . Expert commentary: Dapagliflozin is effective in lowering the plasma glucose concentration with a good safety profile. Dapagliflozin can be utilized in combination with all other antihyperglycaemic agents at all stages of the disease: however, a reduced GFR limits its efficacy. As for the other drugs of the class, Dapagliflozin positively modifies other risk factors for CV disease: these effects will be tested in the so far largest cardiovascular outcome trial for the SGLT2 inhibitors so far, the DECLARE trial, which will communicate whether this class of drugs will be disease-modifier in patients with type 2 diabetes also in primary prevention.

Factors Associated with Microalbuminuria Remission in Patients with Type 2 Diabetes: Importance of Early Intervention for Microalbuminuric Patients (TSUGARU STUDY)

AIM

The aim of this study was to clarify the rates of remission and progression for microalbuminuria in patients with type 2 diabetes (T2DM); and factors associated with remission and progression of diabetic nephropathy (DN).

PATIENTS AND METHODS

T2DM patients with a urinary albumin excretion (UAE) rate of 30-300 mg/gCr who were attending the medical clinic in the Tsugaru region in Japan were enrolled into this prospective, observational study for 36 months (N=317). We investigated the rate of remission (UAE <30 mg/g creatinine (Cr); normal albuminuria) and the rate of progression (UAE ≥300 mg/gCr; overt proteinuria) 36 months after study registration.

RESULTS

The number of patients whose UAE levels were <30 mg/gCr (DN remission) at 36 months after registration was 64 (27.4%), and the number of patients whose UAE levels were ≥300 mg/gCr (DN progression) at 36 months after registration was 32 (13.7%). From multiple logistic regression analysis, the sole factor that contributed to remission at 36 months after registration was the UAE levels at registration (OR: 0.99; 95% CI: 0.98-1.00, p=0.003), and the factors that contributed to progression at 36 months after registration were the levels of UAE (OR: 1.01; 95% CI: 1.01-1.02, p=0.000) and systolic blood pressure (OR: 0.96; 95% CI: 0.93-1.00, p=0.033) at registration.

CONCLUSION

Results suggest that patients with less severe microalbuminuria among microalbuminuric patients might more commonly experience DN remission and that earlier intervention is very important for promoting microalbuminuria remission in DN.

Mechanisms linking empagliflozin to cardiovascular and renal protection

In patients with type 2 diabetes mellitus (T2DM), the main cause of morbidity and mortality is cardiovascular (CV) disease. Diabetic kidney disease, which develops in approximately 40% of patients with T2DM, further increases the risk of CV-related morbidity and mortality. The sodium glucose co-transporter 2 (SGLT2) inhibitor empagliflozin, which provides effective glycaemic control as either monotherapy or as an add-on to other glucose-lowering agents in patients with T2DM, was also shown to improve CV and renal outcomes in the large, randomised, placebo-controlled EMPA-REG OUTCOME trial in patients with T2DM at high risk of CV events. The underlying mechanisms for the CV and renal protective effects of empagliflozin are not fully understood, but are likely to involve a combination of several mechanisms, including empagliflozin-associated body weight and blood pressure reductions, diuresis, a shift in substrate utilisation and activation of tubuloglomerular feedback. The results of ongoing CV outcomes trials with other SGLT2 inhibitors will potentially confirm whether the beneficial CV and renal effects observed in EMPA-REG OUTCOME are unique to empagliflozin or are a drug class effect.

Current therapeutic approaches in the management of hyperglycemia in chronic renal disease

Diabetes mellitus (DM) and chronic kidney disease (CKD) are intricately intertwined. DM is the most common cause of CKD. Adequate control of DM is necessary for prevention of progression of CKD, while careful management of the metabolic abnormalities in CKD will assist in achieving better control of DM. Two of the key organs involved in glucose production are the kidney and the liver. Furthermore, the kidney also plays a role in glucose filtration and reabsorption. In CKD, monitoring of glycemic control using traditional methods such as Hemoglobin A1c (Hba1c) must be done with caution secondary to associated hematological abnormalities in CKD. With regard to medication management in the care of patients with DM, CKD has significant effects. For example, the dosages of oral and non-insulin anti-hyperglycemic agents often need to be modified according to renal function. Insulin metabolism is altered in CKD, and a reduction in insulin dose is almost always needed. Dialysis also affects various aspects of glucose homeostasis, necessitating appropriate changes in therapy. Due to the aforementioned factors glycemic management in patients with DM and CKD can be quiet challenging.

Arterial pressure lability is improved by sodium-glucose cotransporter 2 inhibitor in streptozotocin-induced diabetic rats

To prevent cardiovascular events in patients with diabetes mellitus (DM), it is essential to reduce arterial pressure (AP). Sodium-glucose cotransporter 2 inhibitor (SGLT2i) prevents cardiovascular events via the depressor response in patients with DM. In the present study, we examined whether SGLT2i ameliorates AP lability in DM rats. Ten-week-old male Sprague-Dawley rats were administered a single intravenous injection of streptozotocin (50 mg kg^-1) and were divided into three groups treated with low-dose SGLT2i, vehicle (VEH) or subcutaneously implanted insulin pellets (SGLT2i, VEH and Insulin group, respectively) for 14 days. SGLT2i reduced blood glucose, but its effect was lower than that of insulin. The telemetered mean AP at the end of the experiment did not differ among the SGLT2i, Insulin and VEH groups (83±7 vs. 98±9 vs. 90±8 mm Hg, respectively, n=5 for each). The standard deviation of AP as the index of lability was significantly smaller during the active period in the SGLT2i group than in the VEH group (5.6±0.5 vs. 7.0±0.7 mm Hg, n=5 for each, P<0.05). Sympathetic nerve activity during the active period was significantly lower in the SGLT2i group than in the VEH group. Baroreflex sensitivity (BRS) was significantly higher in the SGLT2i group than in the VEH group. The standard deviation of AP and sympathoexcitation did not differ between the Insulin and VEH groups. In conclusion, SGLT2i at a non-depressor dose ameliorated the AP lability associated with sympathoinhibition during the active period and improved the BRS in streptozotocin-induced DM rats.

Effects of reducing blood pressure on renal outcomes in patients with type 2 diabetes: Focus on SGLT2 inhibitors and EMPA-REG OUTCOME

Empagliflozin, a sodium-glucose cotransporter type 2 (SGLT2) inhibitor, has enabled remarkable reductions in cardiovascular and all-cause mortality as well as in renal outcomes in patients with type 2 diabetes (T2D) and a history of cardiovascular disease in the EMPA-REG OUTCOME. These results have been attributed to haemodynamic rather than metabolic effects, in part due to the osmotic/diuretic action of empagliflozin and the reduction in arterial blood pressure (BP). The present narrative review includes the results of meta-analyses of trials evaluating the effects on renal outcomes of lowering BP in patients with T2D, with a special focus on the influence of baseline and achieved systolic BP, and compares the renal outcome results of the EMPA-REG OUTCOME with those of other major trials with inhibitors of the renin-angiotensin system in patients with T2D and the preliminary findings with other SGLT2 inhibitors, and also evaluates post hoc analyses from the EMPA-REG OUTCOME of special interest as regards the BP-lowering hypothesis and renal function. While systemic BP reduction associated to empagliflozin therapy may have contributed to the renal benefits reported in EMPA-REG OUTCOME, other local mechanisms related to kidney homoeostasis most probably also played a role in the overall protection observed in the trial.

Rodent models of diabetic nephropathy: their utility and limitations

Diabetic nephropathy is the most common cause of end-stage renal disease. Therefore, novel therapies for the suppression of diabetic nephropathy must be developed. Rodent models are useful for elucidating the pathogenesis of diseases and testing novel therapies, and many type 1 and type 2 diabetic rodent models have been established for the study of diabetes and diabetic complications. Streptozotocin (STZ)-induced diabetic animals are widely used as a model of type 1 diabetes. Akita diabetic mice that have an Ins2+/C96Y mutation and OVE26 mice that overexpress calmodulin in pancreatic β-cells serve as a genetic model of type 1 diabetes. In addition, db/db mice, KK-Ay mice, Zucker diabetic fatty rats, Wistar fatty rats, Otsuka Long-Evans Tokushima Fatty rats and Goto-Kakizaki rats serve as rodent models of type 2 diabetes. An animal model of diabetic nephropathy should exhibit progressive albuminuria and a decrease in renal function, as well as the characteristic histological changes in the glomeruli and the tubulointerstitial lesions that are observed in cases of human diabetic nephropathy. A rodent model that strongly exhibits all these features of human diabetic nephropathy has not yet been developed. However, the currently available rodent models of diabetes can be useful in the study of diabetic nephropathy by increasing our understanding of the features of each diabetic rodent model. Furthermore, the genetic background and strain of each mouse model result in differences in susceptibility to diabetic nephropathy with albuminuria and the development of glomerular and tubulointerstitial lesions. Therefore, the validation of an animal model reproducing human diabetic nephropathy will significantly facilitate our understanding of the underlying genetic mechanisms that contribute to the development of diabetic nephropathy. In this review, we focus on rodent models of diabetes and discuss the utility and limitations of these models for the study of diabetic nephropathy.