Effects of sodium glucose co-transporter 2 inhibitors on the kidney

Amelioration of propionic acid-induced autism spectrum disorder in rats through dapagliflozin: The role of IGF-1/IGFBP-3 and the Nrf2 antioxidant pathway

The biological effects of dapagliflozin, a sodium-glucose cotransporter-2 (SGLT2) inhibitor, reveal its antioxidant and anti-inflammatory properties, suggesting therapeutic benefits beyond glycemic control. This study explores the neuroprotective effects of dapagliflozin in a rat model of autism spectrum disorder (ASD) induced by propionic acid (PPA), characterized by social interaction deficits, communication challenges, repetitive behaviors, cognitive impairments, and oxidative stress. Our research aims to find effective treatments for ASD, a condition with limited therapeutic options and significant impacts on individuals and families. PPA induces ASD-like symptoms in rodents, mimicking biochemical and behavioral features of human ASD. This study explores dapagliflozin's potential to mitigate these symptoms, providing insights into novel therapeutic avenues. The findings demonstrate that dapagliflozin enhances the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant pathway and increases levels of neurotrophic and growth factors such as brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1), and insulin-like growth factor-binding protein-3 (IGFBP-3). Additionally, dapagliflozin reduces pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α) and interleukin-17 (IL-17), and decreases the oxidative stress marker malondialdehyde (MDA). Dapagliflozin's antioxidant properties support cognitive functions by modulating apoptotic mechanisms and enhancing antioxidant capacity. These combined effects contribute to reducing learning and memory impairments in PPA-induced ASD, highlighting dapagliflozin's potential as an adjunctive therapy for oxidative stress and inflammation-related cognitive decline in ASD. This study underscores the importance of exploring new therapeutic strategies targeting molecular pathways involved in the pathophysiology of ASD, potentially improving the quality of life for individuals affected by this disorder.

SGLT2-independent effects of canagliflozin on NHE3 and mitochondrial complex I activity inhibit proximal tubule fluid transport and albumin uptake

Beyond glycemic control, SGLT2 inhibitors (SGLT2is) have protective effects on cardiorenal function. Renoprotection has been suggested to involve inhibition of NHE3 leading to reduced ATP-dependent tubular workload and mitochondrial oxygen consumption. NHE3 activity is also important for regulation of endosomal pH, but the effects of SGLT2i on endocytosis are unknown. We used a highly differentiated cell culture model of proximal tubule (PT) cells to determine the direct effects of SGLT2i on Na+-dependent fluid transport and endocytic uptake in this nephron segment. Strikingly, canagliflozin but not empagliflozin reduced fluid transport across cell monolayers and dramatically inhibited endocytic uptake of albumin. These effects were independent of glucose and occurred at clinically relevant concentrations of drug. Canagliflozin acutely inhibited surface NHE3 activity, consistent with a direct effect, but did not affect endosomal pH or NHE3 phosphorylation. In addition, canagliflozin rapidly and selectively inhibited mitochondrial complex I activity. Inhibition of mitochondrial complex I by metformin recapitulated the effects of canagliflozin on endocytosis and fluid transport, whereas modulation of downstream effectors AMPK and mTOR did not. Mice given a single dose of canagliflozin excreted twice as much urine over 24 h compared with empagliflozin-treated mice despite similar water intake. We conclude that canagliflozin selectively suppresses Na+-dependent fluid transport and albumin uptake in PT cells via direct inhibition of NHE3 and of mitochondrial function upstream of the AMPK/mTOR axis. These additional targets of canagliflozin contribute significantly to reduced PT Na+-dependent fluid transport in vivo.NEW & NOTEWORTHY Reduced NHE3-mediated Na+ transport has been suggested to underlie the cardiorenal protection provided by SGLT2 inhibitors. We found that canagliflozin, but not empagliflozin, reduced NHE3-dependent fluid transport and endocytic uptake in cultured proximal tubule cells. These effects were independent of SGLT2 activity and resulted from inhibition of mitochondrial complex I and NHE3. Studies in mice are consistent with greater effects of canagliflozin versus empagliflozin on fluid transport. Our data suggest that these selective effects of canagliflozin contribute to reduced Na+-dependent transport in proximal tubule cells.

The potential for improved outcomes in the prevention and therapy of diabetic kidney disease through 'stacking' of drugs from different classes

Aggressive therapy of diabetic kidney disease (DKD) can not only slow the progression of DKD to renal failure but, if utilized at an early enough stage of DKD, can also stabilize and/or reverse the decline in renal function. The currently recognized standard of therapy for DKD is blockade of the renin-angiotensin system with angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs). However, unless utilized at a very early stage, monotherapy with these drugs in DKD will only prevent or slow the progression of DKD and will neither stabilize nor reverse the progression of DKD to renal decompensation. Recently, the addition of a sodium-glucose cotransporter-2 inhibitor and/or a mineralocorticoid receptor blocker to ACE inhibitors or ARBs has been clearly shown to further decelerate the decline in renal function. The use of glucagon-like peptide-1 (GLP-1) agonists shown promise in decelerating the progression of DKD. Other drugs that may aid in the deceleration the progression of DKD are dipeptidyl peptidase-4 inhibitors, pentoxifylline, statins, and vasodilating beta blockers. Therefore, aggressive therapy with combinations of these drugs (stacking) should improve the preservation of renal function in DKD.

Narrative review investigating the nephroprotective mechanisms of sodium glucose cotransporter type 2 inhibitors in diabetic and nondiabetic patients with chronic kidney disease

Background and aims

Outcome trials using sodium glucose cotransporter type 2 inhibitors have consistently shown their potential to preserve kidney function in diabetic and nondiabetic patients. Several mechanisms have been introduced which may explain the nephroprotective effect of sodium glucose cotransporter type 2 inhibitors beyond lowering blood glucose. This current narrative review has the objective to describe main underlying mechanisms causing a nephroprotective effect and to show similarities as well as differences between proposed mechanisms which can be observed in patients with diabetic and nondiabetic chronic kidney disease.

Methods

We performed a narrative review of the literature on Pubmed and Embase. The research string comprised various combinations of items including "chronic kidney disease", "sodium glucose cotransporter 2 inhibitor" and "mechanisms". We searched for original research and review articles published until march, 2022. The databases were searched independently and the agreements by two authors were jointly obtained.

Results

Sodium glucose cotransporter type 2 inhibitors show systemic, hemodynamic, and metabolic effects. Systemic effects include reduction of blood pressure without compensatory activation of the sympathetic nervous system. Hemodynamic effects include restoration of tubuloglomerular feedback which may improve pathologic hyperfiltration observed in most cases with chronic kidney disease. Current literature indicates that SGLT2i may not improve cortical oxygenation and may reduce medullar oxygenation.

Conclusion

Sodium glucose cotransporter type 2 inhibitors cause nephroprotective effects by several mechanisms. However, several mediators which are involved in the underlying pathophysiology may be different between diabetic and nondiabetic patients.

SGLT2 and DPP4 inhibitors improve Alzheimer's disease-like pathology and cognitive function through distinct mechanisms in a T2D-AD mouse model

Alzheimer's disease (AD) and type 2 diabetes mellitus (T2D) share common features, including insulin resistance. Brain insulin resistance has been implicated as a key factor in the pathogenesis of AD. Recent studies have demonstrated that anti-diabetic drugs sodium-glucose cotransporter-2 inhibitor (SGLT2-i) and dipeptidyl peptidase-4 inhibitor (DPP4-i) improve insulin sensitivity and provide neuroprotection. However, the effects of these two inhibitors on the brain metabolism and insulin resistance remain uninvestigated. We developed a T2D-AD mouse model using a high-fat diet (HFD) for 19 weeks along with a single dose of streptozotocin (100 mg/kg, intraperitoneally) at the fourth week of HFD initiation. Subsequently, the animals were treated with SGLT2-i (empagliflozin, 25 mg/kg/day orally [p.o.]) and DPP4-i (sitagliptin, 100 mg/kg/day p.o.) for 7 weeks. Subsequently, behavioral tests were performed, and the expression of insulin signaling, AD-related, and other signaling pathway proteins in the brain were examined. T2D-AD mice not only showed increased blood glucose levels and body weight but also insulin resistance. SGLT2-i and DPP4-i effectively ameliorated insulin sensitivity and reduced body weight in these mice. Furthermore, SGLT2-i and DPP4-i significantly improved hippocampal-dependent learning, memory, and cognitive functions in the T2D-AD mouse model. Interestingly, SGLT2-i and DPP4-i reduced the hyperphosphorylated tau (pTau) levels and amyloid β (Aβ) accumulation and enhanced brain insulin signaling. SGLT2-i reduced pTau accumulation through the angiotensin converting enzyme-2/angiotensin (1-7)/ mitochondrial assembly receptor axis, whereas DPP4-i reduced Aβ accumulation by increasing insulin-degrading enzyme levels. These findings suggest that SGLT2-i and DPP4-i prevent AD-like pathology and cognitive dysfunction in T2D mice potentially through affecting brain insulin signaling via different mechanisms.

The Pillars for Renal Disease Treatment in Patients with Type 2 Diabetes

The diabetes epidemic and the increasing number of patients with diabetic chronic vascular complications poses a significant challenge to health care providers. Diabetic kidney disease is a serious diabetes-mediated chronic vascular complication and represents a significant burden for both patients and society in general. Diabetic kidney disease not only represents the major cause of end stage renal disease but is also paralleled by an increase in cardiovascular morbidity and mortality. Any interventions to delay the development and progression of diabetic kidney disease are important to reduce the associated cardiovascular burden. In this review we will discuss five therapeutic tools for the prevention and treatment of diabetic kidney disease: drugs inhibiting the renin-angiotensin-aldosterone system, statins, the more recently recognized sodium-glucose co-transporter-2 inhibitors, glucagon-like peptide 1 agonists, and a novel non-steroidal selective mineralocorticoid receptor antagonist.

Effect of sodium-glucose cotransporter 2 inhibitors on the rate of decline in kidney function: A systematic review and meta-analysis

AIM

To investigate the influence of sodium/glucose cotransporter-2 inhibitors (SGLT-2i) on renal function during the course of its administration, particularly in the initial weeks.

MATERIALS AND METHODS

Randomized controlled trials (RCTs) related to SGLT-2i were searched in databases (MEDLINE, EMBASE, and Cochrane Central Register) from the database's inception to August 31, 2021. All RCTs reported the kidney outcomes of SGLT2i versus active or placebo control were included, regardless of the presence of diabetes in the patients and the baseline estimated glomerular filtration rate (eGFR). The Cochrane Collaboration risk of bias tool was used to assess the quality of the included studies. All outcome comparisons were performed using the RevMan 5.4 software.

RESULTS

Eleven RCTs with 58 534 participants reporting prespecified renal outcomes were identified. There was no heterogeneity in the baseline eGFR and urine albumin-to-creatinine ratio in the included studies. In the initial 2-4 weeks, there was an acute decline of eGFR in the SGLT-2i group compared with placebo group (weighted mean difference [WMD] -3.35 ml/min/1.73 m² ; 95% CI, -3.81 to -2.90; I²  = 35%, p = .15); When compared to baseline eGFR in the SGLT-2i group, the WMD was -4.02 ml/min/1.73 m² (95% confidence interval [CI], -3.61 to -4.44; I²  = 0%, p = .45). The renoprotective effect gradually appeared, and the decline rate of eGFR in the SGLT-2i group was sustained slower than placebo. However, the statistically significant benefit of SGLT-2i did not appear until the 104th week (the second year) (WMD 0.35 ml/min/1.73 m² , 95% CI, 0.04 to 0.66; I²  = 45%, p = .08). Subgroup analysis showed SGLT-2i had a similar benefit on renal function regardless of baseline eGFR values.

CONCLUSION

SGLT-2i consistently slowed the deterioration of eGFR since the early stage of administration, even in patients with chronic kidney disease. However, there was an acute decline in eGFR in the initial 2-4 weeks; afterwards the renoprotective effect of SGLT-2i gradually appeared and remained stable in the next few years.

Knowledge domain and emerging trends in empagliflozin for heart failure: A bibliometric and visualized analysis

Objective

Empagliflozin (EMPA), a sodium-glucose cotransporter 2 inhibitor (SGLT2i), is recommended for all patients with Heart failure (HF) to reduce the risk of Cardiovascular death, hospitalization, and HF exacerbation. Qualitative and quantitative evaluation was conducted by searching relevant literatures of EMPA for Heart Failure from 2013 to 2022, and visual analysis in this field was conducted.

Methods

The data were from the Web of Science Core Collection database (WOSCC). The bibliometric tools, CiteSpace and VOSviewer, were used for econometric analysis to probe the evolvement of disciplines and research hotspots in the field of EMPA for Heart Failure.

Results

A total of 1461 literatures with 43861 references about EMPA for Heart Failure in the decade were extracted from WOSCC, and the number of manuscripts were on a rise. In the terms of co-authorship, USA leads the field in research maturity and exerts a crucial role in the field of EMPA for Heart Failure. Multidisciplinary research is conducive to future development. With regards to literatures, we obtained 9 hot paper, 93 highly cited literatures, and 10 co-cited references. The current research focuses on the following three aspects: EMPA improves left ventricular remodeling, exert renal protection, and increases heart rate variability.

Conclusion

Based on methods such as bibliometrics, citation analysis and knowledge graph, this study analyzed the current situation and trend of EMPA for Heart Failure, sorted out the knowledge context in this field, and provided reference for current and future prevention and scientific research.

Mediators of the improvement in heart failure outcomes with empagliflozin in the EMPA-REG OUTCOME trial

Aims

In the EMPA‐REG OUTCOME trial, empagliflozin reduced risk of death from heart failure (HF) or hospitalization for heart failure (HHF) versus placebo in patients with type 2 diabetes mellitus (T2DM) and established cardiovascular (CV) disease. We evaluated post hoc the degree to which covariates mediated the effects of empagliflozin on HHF or HF death.

Methods and results

A mediator had to fulfil the following criteria: (i) affected by active treatment, (ii) associated with the outcome, and finally (iii) adjustment for it results in a reduced treatment effect compared with unadjusted analysis. Potential mediators were calculated as change from baseline or updated mean and evaluated in univariable analyses as time‐dependent covariates in Cox regression of time to HHF or HF death; those with the largest mediating effects were then included in a multivariable analysis. Increases in heart rate, log urine albumin‐to‐creatinine ratio (UACR), waist circumference, and uric acid were associated with increased risk of HHF or HF death; increases in high‐density lipoprotein cholesterol, estimated glomerular filtration rate, haematocrit, haemoglobin, and albumin were associated with reduced risk of HHF or HF death. In univariable analyses, change from baseline in haematocrit, haemoglobin, albumin, uric acid, and logUACR mediated 51%, 54%, 23%, 24%, and 27% of the risk reduction with empagliflozin versus placebo, respectively. Multivariable analysis including haemoglobin, logUACR, and uric acid mediated 85% of risk reduction with similar results when updated means were evaluated.

Conclusions

Changes in haematocrit and haemoglobin were the most important mediators of the reduction in HHF and death from HF in patients with T2DM and established CV disease treated with empagliflozin. Albumin, uric acid, and logUACR had smaller mediating effects in this population.

Towards Better Drug Repositioning: Targeted Immunoinflammatory Therapy for Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the most common and important microvascular complications of diabetes mellitus (DM). The main clinical features of DN are proteinuria and a progressive decline in renal function, which are associated with structural and functional changes in the kidney. The pathogenesis of DN is multifactorial, including genetic, metabolic, and haemodynamic factors, which can trigger a sequence of events. Controlling metabolic risks such as hyperglycaemia, hypertension, and dyslipidaemia is not enough to slow the progression of DN. Recent studies emphasized immunoinflammation as a critical pathogenic factor in the progression of DN. Therefore, targeting inflammation is considered a potential and novel treatment strategy for DN. In this review, we will briefly introduce the inflammatory process of DN and discuss the anti-inflammatory effects of antidiabetic drugs when treating DN.

Cardiovascular Outcomes in Trials of New Antidiabetic Drug Classes

Type 2 diabetes is among the most prevalent chronic diseases worldwide and the prevention of associated cardiovascular complications is an important treatment goal. Sodium–glucose co-transporter 2 (SGLT2) inhibitors, glucagon-like peptide 1 (GLP-1) receptor agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors are second-line options after metformin, while cardiovascular outcome trials have been conducted to establish the cardiovascular safety of these antidiabetic drug classes. SGLT2 inhibitors have been shown to have the best overall mortality, renal and cardiovascular outcomes. Reduction in hospitalisation for heart failure is particularly consistent. GLP-1 receptor agonists have also showed some benefits, especially in stroke prevention. DPP-4 inhibitors showed neutral effects on cardiovascular outcomes, but may increase the incidence of heart failure. Favourable outcomes observed in trials of SGLT2 inhibitors mean that these should be the preferred second-line option. DPP-4 inhibitors are useful for patients with diabetes at low cardiovascular risk.

The Impact of Empagliflozin on Obstructive Sleep Apnea and Cardiovascular and Renal Outcomes: An Exploratory Analysis of the EMPA-REG OUTCOME Trial

OBJECTIVE

To explore the effects of empagliflozin on the incidence of obstructive sleep apnea (OSA) and its effects on metabolic, cardiovascular (CV), and renal outcomes among participants with or without OSA in the EMPA-REG OUTCOME trial.

RESEARCH DESIGN AND METHODS

Participants with diabetes and CV disease were randomized to empagliflozin (10 and 25 mg) or placebo daily in addition to standard of care. OSA was assessed by investigator report using Medical Dictionary for Regulatory Activities version 18.0, and CV outcomes were independently adjudicated. Analyses were performed using multivariable-adjusted Cox regression models.

RESULTS

OSA was reported in 391 of 7,020 (5.6%) participants at baseline. Those with OSA were more likely to be male (83% vs. 71%) and to have moderate to severe obesity (BMI ≥35 kg/m²; 55% vs. 18%). Over a median of 3.1 years, empagliflozin had similar placebo-adjusted reductions in HbA_1c, waist circumference, and systolic blood pressure, regardless of OSA status, but a larger effect on weight (adjusted mean ± SE difference at week 52: OSA vs. no OSA -2.9 ± 0.5 vs. -1.9 ± 0.1 kg). Incidence of 3-point major adverse CV events, CV death, heart failure hospitalization, and incident or worsening nephropathy in the placebo group was 1.2- to 2.0-fold higher for those with baseline OSA compared with those without. Empagliflozin significantly reduced the risk for outcomes regardless of OSA status (P-interaction all >0.05). Fifty patients reported a new diagnosis of OSA through 7 days after medication discontinuation, and this occurred less often with empagliflozin treatment (hazard ratio 0.48 [95% CI 0.27, 0.83]).

CONCLUSIONS

In EMPA-REG OUTCOME, participants with OSA had greater comorbidity and higher frequency of CV and renal events. Empagliflozin had favorable effects on risk factors and CV and renal outcomes regardless of preexisting OSA and may also reduce the risk for new-onset OSA.

Canagliflozin for the Treatment of Diabetic Kidney Disease and Implications for Clinical Practice: A Narrative Review

Type 2 diabetes mellitus (T2DM) affects millions of people worldwide, elevating their risk of developing a range of complications, including chronic kidney disease (CKD). People with T2DM and CKD (i.e., diabetic kidney disease, DKD) have an increased risk of progressing to end-stage kidney disease (ESKD), experiencing cardiovascular complications, and premature death. Despite this, DKD is primarily addressed through management of risk factors, and there are few pharmaceutical treatments capable of reversing or delaying disease progression. Canagliflozin is a sodium glucose co-transporter 2 inhibitor that was initially developed as a blood glucose-lowering agent for people with T2DM. Evidence from clinical trials of canagliflozin in people with T2DM, as well as evidence from cardiovascular outcomes trials in people with T2DM and high cardiovascular risk, provided preliminary evidence suggesting that it may also have beneficial renal effects. The Canagliflozin and Renal Events in Diabetes with Established Nephropathy Clinical Evaluation (CREDENCE) trial was a dedicated renal outcomes trial of canagliflozin that assessed its renal effects in people with DKD. Overall, the CREDENCE trial demonstrated that canagliflozin improves renal outcomes and slows early disease progression in people with DKD. These data supported the approval of canagliflozin for the treatment DKD, the first new treatment in almost 20 years; therefore, it is important for clinicians to understand how to implement this treatment in their clinical practice.

Current Data Regarding the Relationship between Type 2 Diabetes Mellitus and Cardiovascular Risk Factors

Reducing cardiovascular risk (CVR) is the main focus of diabetes mellitus (DM) management nowadays. Complex pathogenic mechanisms that are the subject of this review lead to early and severe atherosclerosis in DM patients. Although it is not a cardiovascular disease equivalent at the moment of diagnosis, DM subjects are affected by numerous cardiovascular complications, such as acute coronary syndrome, stroke, or peripheral artery disease, as the disease duration increases. Therefore, early therapeutic intervention is mandatory and recent guidelines focus on intensive CVR factor management: hyperglycaemia, hypertension, and dyslipidaemia. Most important, the appearance of oral or injectable antidiabetic medication such as SGLT-2 inhibitors or GLP-1 agonists has proven that an antidiabetic drug not only reduces glycaemia, but also reduces CVR by complex mechanisms. A profound understanding of intimate mechanisms that generate atherosclerosis in DM and ways to inhibit or delay them are of the utmost importance in a society where cardiovascular morbidity and mortality are predominant.

Effectiveness in the inhibition of dapagliflozin and canagliflozin on M-type K+ current and α-methylglucoside-induced current in pituitary tumor (GH3) and pheochromocytoma PC12 cells

Dapagliflozin (DAPA) or canagliflozin (CANA), Na⁺-dependent glucose co-transporter type 2 (SGLT2) inhibitors, were used for treatment of type II diabetes mellitus. Addition of DAPA or CANA suppressed M-type K⁺ current (I_K(M)) in pituitary tumor (GH₃) and pheochromocytoma PC12 cells. The IC₅₀ value for DAPA- or CANA-mediated inhibition of I_K(M) in GH₃ cells was 0.11 or 0.42 μM, respectively. The presence of DAPA (0.1 μM) shifted the steady-state activation of I_K(M) to less depolarized potential without changing the gating charge of the current. During high-frequency depolarizing pulses, I_K(M) magnitude was reduced by DAPA; however, DAPA-induced block of I_K(M) remained effective. The amplitude of neither erg-mediated K⁺ current nor hyperpolarization-activated cation current in GH₃ cells was modified in the presence of 1 μM DAPA. Alternatively, addition of DAPA, CANA, phlorizin or chlorotoxin effectively suppressed α-methylglucoside-(αMG-) induced current (I_αMG) in GH₃ cells, albeit inability of tefluthrin (activator of I_Na) to suppress this current. DAPA shifted the charge-voltage relation of presteady-state I_αMG in a rightward and downward direction with no change in the gating charge of the I_αMG. Under current-clamp recordings, subsequent additions of DAPA, but still in the continued presence of αMG, increased the firing rate of spontaneous action potentials stimulated by αMG. Our results suggested that activity of SGLT was expressed functionally in GH₃ and PC12 cells. Therefore, inhibitory actions of DAPA or CANA on the amplitude and gating of I_K(M) might provide a yet unidentified mechanism through which the SGLT1 or SGLT2 activity were attenuated in unclamped cells occurring in vivo.

Renal Evaluation and Protection

Diabetes and diabetic nephropathy have become more prevalent in the elderly population. Diabetic nephropathy has become increasingly prevalent in the elderly population. The presence of this disease in an age group suffering multiple comorbidities has altered the pathophysiology and leading cause of mortality. Mortality has become linked more often to cardiovascular events rather than progression of end-stage-renal-disease, which explains the recent shift of focus of trials to improving cardiovascular-outcomes in patients with diabetes. In this chapter, we emphasize the difference in treatment modalities and goals of therapy in elderly versus young. In addition, we discuss results from recent outcome trials with regards to renal benefits of sodium-glucose co-transporter-2-inhibitors and glucagon-like peptide-1-receptor-agonists.

Renal hyperfiltration defined by high estimated glomerular filtration rate: A risk factor for cardiovascular disease and mortality

Renal hyperfiltration, defined as an increased glomerular filtration rate above normal values, is associated with early phases of kidney disease in the setting of various conditions such as obesity and diabetes. Although it is recognized that glomerular hyperfiltration, that is, increased filtration per nephron unit (usually studied at low glomerular filtration levels and often referred to as single nephron hyperfiltration), is a risk factor for the progression of chronic kidney disease, the implications of having renal hyperfiltration for cardiovascular disease and mortality risk are incompletely understood. Recent evidence from diverse populations, including healthy individuals and patients with diabetes or established cardiovascular disease, suggests that renal hyperfiltration is associated with a higher risk of cardiovascular disease and all-cause mortality. In this review, we critically summarize the existing studies, discuss possible mechanisms, and describe the remaining gaps in our knowledge regarding the association of renal hyperfiltration with cardiovascular disease and mortality risk.

SGLT2 Inhibitors: A Review of Their Antidiabetic and Cardioprotective Effects

Type 2 diabetes mellitus is a chronic metabolic disease associated with high cardiovascular (CV) risk. Sodium-glucose co-transporter 2 inhibitors (SGLT2i) are the latest class of antidiabetic medication that inhibit the absorption of glucose from the proximal tubule of the kidney and hence cause glycosuria. Four SGLT2i are currently commercially available in many countries: canagliflozin, dapagliflozin, empagliflozin, and ertugliflozin. SGLT2i reduce glycated hemoglobin by 0.5%-1.0% and have shown favorable effects on body weight, blood pressure, lipid profile, arterial stiffness and endothelial function. More importantly, SGLT2i have demonstrated impressive cardioprotective and renoprotective effects. The main mechanisms underlying their cardioprotective effects have been attributed to improvement in cardiac cell metabolism, improvement in ventricular loading conditions, inhibition of the Na+/H+ exchange in the myocardial cells, alteration in adipokines and cytokines production, as well as reduction of cardiac cells necrosis and cardiac fibrosis. The main adverse events of SGLT2i include urinary tract and genital infections, as well as euglycemic diabetic ketoacidosis. Concerns have also been raised about the association of SGLT2i with lower limb amputations, Fournier gangrene, risk of bone fractures, female breast cancer, male bladder cancer, orthostatic hypotension, and acute kidney injury.

Effects of dapagliflozin on development and progression of kidney disease in patients with type 2 diabetes: an analysis from the DECLARE-TIMI 58 randomised trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors have shown beneficial effects on renal outcomes mainly in patients with established atherosclerotic cardiovascular disease. Here we report analyses of renal outcomes with the SGLT2 inhibitor dapagliflozin in the DECLARE-TIMI 58 cardiovascular outcomes trial, which included patients with type 2 diabetes both with and without established atherosclerotic cardiovascular disease and mostly with preserved renal function.

METHODS

In DECLARE-TIMI 58, patients with type 2 diabetes, HbA_1c 6·5-12·0% (47·5-113·1 mmol/mol), with either established atherosclerotic cardiovascular disease or multiple risk factors, and creatinine clearance of at least 60 mL/min were randomly assigned (1:1) to 10 mg dapagliflozin or placebo once daily. A prespecified secondary cardiorenal composite outcome was defined as a sustained decline of at least 40% in estimated glomerular filtration rate [eGFR] to less than 60 mL/min per 1·73m², end-stage renal disease (defined as dialysis for at least 90 days, kidney transplantation, or confirmed sustained eGFR <15mL/min per 1·73 m²), or death from renal or cardiovascular causes; a prespecified renal-specific composite outcome was the same but excluding death from cardiovascular causes. In this renal analysis, we report findings for the components of these composite outcomes, subgroup analysis of these composite outcomes, and changes in eGFR at different timepoints. DECLARE-TIMI 58 is registered with ClinicalTrials.gov, number NCT01730534.

FINDINGS

The trial took place between April 25, 2013, and Sept 18, 2018; median follow-up was 4·2 years (IQR 3·9-4·4). Of the 17 160 participants who were randomly assigned, 8162 (47·6%) had an eGFR of at least 90 mL/min per 1·73 m², 7732 (45·1%) had an eGFR of 60 to less than 90 mL/min per 1·73 m², and 1265 (7·4%) had an eGFR of less than 60 mL/min per 1·73 m² at baseline (one participant had missing data for eGFR); 6974 (40·6%) had established atherosclerotic cardiovascular disease and 10 186 (59·4%) had multiple risk factors. As previously reported, the cardiorenal secondary composite outcome was significantly reduced with dapagliflozin versus placebo (hazard ratio [HR] 0·76, 95% CI 0·67-0.87; p<0·0001); excluding death from cardiovascular causes, the HR for the renal-specific outcome was 0·53 (0·43-0·66; p<0·0001). We identified a 46% reduction in sustained decline in eGFR by at least 40% to less than 60 mL/min per 1·73 m² (120 [1·4% vs 221 [2·6%]; HR 0·54 [95% CI 0·43-0·67]; p<0·0001). The risk of end-stage renal disease or renal death was lower in the dapagliflozin group than in the placebo group (11 [0·1%] vs 27 [0·3%]; HR 0·41 [95% CI 0·20-0·82]; p=0·012). Both the cardiorenal and renal-specific composite outcomes were improved with dapagliflozin versus placebo across various prespecified subgroups, including those defined by baseline eGFR (cardiorenal outcome p_interaction=0·97; renal-specific outcome p_interaction=0·87) and the presence or absence of established atherosclerotic cardiovascular disease (cardiorenal outcome p_interaction=0·67; renal-specific outcome p_interaction=0·72). 6 months after randomisation, the mean decrease in eGFR was larger in the dapagliflozin group than in the placebo group. The mean change equalised by 2 years, and at 3 and 4 years the mean decrease in eGFR was less with dapagliflozin than with placebo.

INTERPRETATION

Dapagliflozin seemed to prevent and reduce progression of kidney disease compared with placebo in this large and diverse population of patients with type 2 diabetes with and without established atherosclerotic cardiovascular disease, most of whom had preserved renal function.

FUNDING

AstraZeneca.

Substantial and Sustained Improvements in Blood Pressure, Weight and Lipid Profiles from a Carbohydrate Restricted Diet: An Observational Study of Insulin Resistant Patients in Primary Care

Hypertension is the second biggest known global risk factor for disease after poor diet; perhaps lifestyle interventions are underutilized? In a previous small pilot study, it was found that a low carbohydrate diet was associated with significant improvements in blood pressure, weight, 'deprescribing' of medications and lipid profiles. We were interested to investigate if these results would be replicated in a larger study based in 'real world' GP practice. 154 patients with type 2 diabetes or impaired glucose tolerance were recruited into an observational cohort study in primary care. The effects of a low carbohydrate diet sustained for an average of two years (interquartile range 10-32 months) on cardiovascular risk factors were examined. Results demonstrate significant and substantial reductions in blood pressure (mean reduction of systolic BP 10.9 mmHg (interquartile range 0-22 mmHg) (p < 0.0001), mean reduction in diastolic BP 6.3 mmHg (interquartile range 0-12.8 mmHg) (p < 0.0001) and mean weight reduction of 9.5 Kg (interquartile range 5-13 Kg) (p < 0.0001) together with marked improvement in lipid profiles. This occurred despite a 20% reduction in anti-hypertensive medications. This novel and potentially highly effective dietary modification, done very cheaply alongside routine care, offers hope that should be tested in a large prospective trial.

A Potential Mechanism of Cardio-Renal Protection with Sodium-Glucose Cotransporter 2 Inhibitors: Amelioration of Renal Congestion

Background: This review considers anew the etiology of the cardio-renal protective effect of sodium-glucose cotransporter 2 (SGLT2) inhibitors by extending the discussion to renal congestion, inherent in diabetic kidney disease (DKD) even at an early stage of nephropathy in which heart failure (HF) or salt and water accumulation is asymptomatic. Summary: The interstitial fluid (IF) space of the kidney space plays a crucial role for tubulointerstitial inflammation, renal hypoxia, and ischemic injury, which often leads to renal progression. In DKD, as a result of hyperglycemic milieu, excessive salt and water can be accumulated in the IF space, creating renal congestion. I hypothesize that SGLT2 inhibitors cause a shift in extracellular water from the IF space to the intravascular space to compensate for the SGLT2 inhibitor-induced hypovolemia. This decrease in IF volume ameliorates the IF space milieu and may reduce inflammation, hypoxia, and ischemic injury. Message: The present review proposes a novel theory; unlike other hypoglycemic agents or diuretics, SGLT2 inhibitor could protect DKD from failing by improving latent renal congestion even without symptomatic HF.

Renal effects of sodium-glucose cotransporter-2 inhibitors in patients with type 2 diabetes and renal impairment

In patients with type 2 diabetes (T2D), microvascular changes in the kidney often result in diabetic kidney disease (DKD), the progression of which is associated with an increased risk of cardiovascular (CV) and all-cause mortality. Sodium-glucose cotransporter-2 inhibitors (SGLT-2is) are a newer class of oral glucose-lowering therapies that were associated with significant reductions in the risk of major adverse CV events, CV death, and hospitalization for heart failure compared with placebo in CV outcomes trials (CVOTs) of patients with T2D and established CV disease or varying levels of CV risk. In addition, SGLT-2is reduced the risks of clinically relevant renal outcomes in these large randomized studies, indicating the potential for renoprotective effects in patients with T2D and DKD. This review discussed the non-glycemic effects of SGLT-2is in patients with T2D and renal impairment, including reductions in systolic and diastolic blood pressure, decreases in albuminuria and plasma uric acid, changes in estimated glomerular filtration rate, and minimal changes in electrolytes. Potential mechanisms for the renoprotective effects of SGLT-2is observed in CVOTs were considered, including the likely incremental benefits of SGLT-2is when added to renin-aldosterone-angiotensin system inhibitors (RAASis). The possibility of extending the use of SGLT-2is to patients with non-DKD was also discussed. Although the exact mechanisms by which SGLT-2is improve renal outcomes are not fully understood, they are likely to be multifactorial and additive when these drugs are used in combination with RAASis in patients with DKD.

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

AIMS

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

MAIN METHODS

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

KEY FINDINGS

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

SIGNIFICANCE

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

Sodium glucose cotransporter (SGLT)-2 inhibitors: Do we need them for glucose-lowering, for cardiorenal protection or both?

Sodium glucose cotransporter (SGLT)-2 inhibitors are the newest addition to our treatment armamentarium for the management of hyperglycemia in type 2 diabetes. Glucose-lowering per se reduces the risk of microvascular complications, but not the risk of cardiovascular disease, including heart failure and cardiovascular mortality. Also, even when embedded in optimal cardiovascular prevention, a large residual risk remains with respect to progression of diabetic kidney disease. SGLT-2 inhibitors lower blood glucose levels by inducing glucosuria. Through various proposed mechanisms, among which diuretic and natriuretic effects, SGLT-2 inhibitors decrease heart failure hospitalization, reduce cardiovascular mortality, and mitigate progression of diabetic kidney disease. In this perspective, we will discuss the glucose-lowering and other protective effects of SGLT-2 inhibitors on the cardiorenal axis, both in primary and secondary prevention. By comparing the glycemic and pleiotropic effects of these agents to other glucose-lowering drugs, we will address questions around whether SGLT-2 inhibitors should be considered primarily as glucose-lowering agents, cardiorenal drugs or both.

Effects of glucose-lowering agents on surrogate endpoints and hard clinical renal outcomes in patients with type 2 diabetes

Diabetic kidney disease (DKD) represents an enormous burden in patients with type 2 diabetes mellitus (T2DM). Preclinical studies using most glucose-lowering agents have suggested renal-protective effects, but the proposed mechanisms of renoprotection have yet to be defined, and the promising results from experimental studies remain to be translated into human clinical findings to improve the prognosis of patients at risk of DKD. Also, it is important to distinguish effects on surrogate endpoints, such as decreases in albuminuria and estimated glomerular filtration rate (eGFR), and hard clinical endpoints, such as progression to end-stage renal disease (ESRD) and death from renal causes. Data regarding insulin therapy are surprisingly scarce, and it is nearly impossible to separate the effects of better glucose control from those of insulin per se, whereas favourable preclinical data with metformin, thiazolidinediones and dipeptidyl peptidase (DPP)-4 inhibitors are plentiful, and positive effects have been observed in clinical studies, at least for surrogate endpoints. The most favourable renal results have been reported with glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter type-2 inhibitors (SGLT2is). Significant reductions in both albuminuria and eGFR decline have been reported with these classes of glucose-lowering medications compared with placebo and other glucose-lowering agents. Moreover, in large prospective cardiovascular outcome trials using composite renal outcomes as secondary endpoints, both GLP-1RAs and SGLT2is added to standard care reduced renal outcomes combining persistent macro-albuminuria, doubling of serum creatinine, progression to ESRD and kidney-related death; however, to date, only SGLT2is have been clearly shown to reduce such hard clinical outcomes. Yet, as the renoprotective effects of SGLT2is and GLP-1RAs appear to be independent of glucose-lowering activity, the underlying mechanisms are still a matter of debate. For this reason, further studies with renal outcomes as primary endpoints are now awaited in T2DM patients at high risk of DKD, including trials evaluating the potential add-on benefits of combined GLP-1RA-SGLT2i therapies.