SGLT2 Inhibitors Produce Cardiorenal Benefits by Promoting Adaptive Cellular Reprogramming to Induce a State of Fasting Mimicry: A Paradigm Shift in Understanding Their Mechanism of Action

Nonalcoholic fatty liver disease and cardiovascular concerns: The time for hepatologist and cardiologist close collaboration

Nonalcoholic fatty liver disease (NAFLD) has emerged as the most common chronic liver cell damage worldwide. It is strongly associated with an increased risk of cardiovascular disease (CVD). There are not enough recommendations for screening subjects with nonalcoholic steatohepatitis cirrhosis, who are not candidates for liver transplantation, nor who are asymptomatic with NAFLD without cirrhosis. In the current comprehensive narrative review, we aimed to evaluate the associations between CVD and NAFLD. Distinguishing the mechanisms linking these two disorders offers the opportunity to develop targeted therapies. Moreover, we will discuss screening approaches (whom and how-to) and treatment modalities proposed to reduce cardiovascular risk in patients with NAFLD.

Cardiovascular benefits of sodium-glucose cotransporter 2 inhibitors in diabetic and nondiabetic patients

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) were developed as antidiabetic agents, but accumulating evidence has shown their beneficial effects on the cardiovascular system. Analyses of the EMPA-REG OUTCOME trial (Empagliflozin Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients) suggested that these benefits are independent of glycemic control. Several large-scale outcome trials of SGLT2i also showed cardiovascular benefits in nondiabetic patients, strengthening this perspective. Extensive animal and clinical studies have likewise shown that mechanisms other than the antihyperglycemic effect underlie the cardiovascular benefits. Recent clinical guidelines recommend the use of SGLT2i in patients with type 2 diabetes mellitus and cardiovascular diseases because of the proven cardiovascular protective effects. Since the cardiovascular benefits are independent of glycemic control, the therapeutic spectrum of SGLT2i will likely be extended to nondiabetic patients.

Heart Failure And Diabetes: Perspective Of A Dangerous Association

The relationship between diabetes and risk of heart failure has been described in previous trials, releasing the importance of the hyperglycemic state that added to other risk factors, favors the development of coronary heart disease. The mechanism by which in the absence of hypertension, obesity and/or dyslipidemia, diabetic patients develop cardiomyopathyhas been less studied. Recently, the Sodium Glucose Co-transporter type 2 inhibitors (SGLT2 inhibitors) used for the treatment of heart failure patients with or without diabetes has been a breakthrough in the field of medicine. This review describes the established pathophysiology of diabetic cardiomyopathy and SGLT2 inhibitors, their mechanisms of action, and benefits in this group of patients.

Additional Features in the Treatment of Patients with Chronic Heart Failure. From EMPA-REG OUTCOME Study to EMPEROR-REDUCED Study. Resolution of the On-line Scientific Meeting of Moscow Experts

The results of the international multicenter study EMPEROR-REDUCED were reviewed the on-line scientific meeting of Moscow experts on October 30, 2020. Some proposals and recommendations for further study of the cardiovascular and renal effects of empagliflozin and its use in clinical practice in patients with chronic heart failure with reduced ejection fraction were accepted.

Protective effects of SGLT-2 inhibitors across the cardiorenal continuum: two faces of the same coin

The cardiovascular and renal systems are closely interconnected in health and disease. Disorders affecting one of these systems frequently involve the other. Both diseases progress through a continuous chain of events, defined as the 'cardiorenal continuum', which is initiated by risk factors that lead to subclinical disease, clinical events, and ultimately to heart failure and end-stage kidney disease. Previous studies have shown that interventions anywhere along this chain of events can interrupt the pathophysiological cascade and provide cardiovascular and/or kidney 'protection'. More recently, clinical trials with SGLT-2 inhibitors (SGLT2i) have shown a significant reduction in cardiovascular and kidney outcomes. Evidence from EMPA-REG OUTCOME, CANVAS Program, DECLARE-TIMI 58, VERTIS-CV, CREDENCE, and more recently DAPA-HF, EMPEROR-Reduced, and DAPA-CKD show that the beneficial effects of SGLT2i are observed across all stages of the cardiorenal continuum, ranging from patients with diabetes and multiple risk factors to those with established cardiovascular disease and even independently of diabetes status. This review provides a critical appraisal of the efficacy and safety of SGLT2i, demonstrating that this is a novel way to disrupt the chain of pathological events in the cardiorenal continuum and prevent cardiovascular and kidney disease in patients with and without diabetes.

SGLT2 inhibitors and cardiovascular and renal outcomes: a meta-analysis and trial sequential analysis

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce cardiovascular events and renal outcomes in patients with diabetes mellitus (DM). This meta-analysis aimed to provide a thorough evaluation regarding the efficacy and safety of SGLT2 inhibitors. Data search of MEDLINE/PubMed, Embase, and Cochrane Library databases and ClinicalTrials.com from inception through November 26, 2020. We included randomized trials, SGLT2 inhibitors compared with placebo, patients with or without diabetes at recruitment, and reporting the incidence of cardiovascular or renal outcomes. Two authors extracted pertinent data into predefined data collection tables. Ten trials were included (71,553 patients). The mean age was 64.7 ± 8.4 years, with 65.1% male. Follow-up durations range 9-50 months. Inhibition of SGLT2 resulted in lower composite outcome of heart failure (HF) hospitalization or cardiovascular death (RR 0.76, 95% CI 0.73-0.81, P < 0.01) and lower risk of renal outcomes (RR 0.68, 95% CI 0.60-0.77, P < 0.01). Furthermore, SGLT2 inhibitors were associated with lower major adverse cardiovascular events (MACEs), HF hospitalization, cardiovascular mortality, all-cause mortality, myocardial infarction, and serious adverse events, compared with placebo (P < 0.05). Sensitivity analyses revealed lower MACE events also in patients with HF, and a lower HF hospitalization and cardiovascular mortality in non-diabetic patients (P < 0.05). While the amputation risk was comparable between the two groups, the risk of diabetic ketoacidosis was higher in the SGLT2 inhibitor group. Inhibition of SGLT2 in patients with DM and prevalent ASCVD reduces the risk of HF hospitalization, cardiovascular mortality, all-cause mortality, MACE, and renal outcomes without increasing the risk of serious adverse events or amputation.

Effects of SGLT2 Inhibitors on Kidney and Cardiovascular Function

SGLT2 inhibitors are antihyperglycemic drugs that protect kidneys and the heart of patients with or without type 2 diabetes and preserved or reduced kidney function from failing. The involved protective mechanisms include blood glucose-dependent and -independent mechanisms: SGLT2 inhibitors prevent both hyper- and hypoglycemia, with expectedly little net effect on HbA1C. Metabolic adaptations to induced urinary glucose loss include reduced fat mass and more ketone bodies as additional fuel. SGLT2 inhibitors lower glomerular capillary hypertension and hyperfiltration, thereby reducing the physical stress on the filtration barrier, albuminuria, and the oxygen demand for tubular reabsorption. This improves cortical oxygenation, which, together with lesser tubular gluco-toxicity, may preserve tubular function and glomerular filtration rate in the long term. SGLT2 inhibitors may mimic systemic hypoxia and stimulate erythropoiesis, which improves organ oxygen delivery. SGLT2 inhibitors are proximal tubule and osmotic diuretics that reduce volume retention and blood pressure and preserve heart function, potentially in part by overcoming the resistance to diuretics and atrial-natriuretic-peptide and inhibiting Na-H exchangers and sympathetic tone.

Empagliflozin Effects on Pulmonary Artery Pressure in Patients With Heart Failure: Results From the EMBRACE-HF Trial

BACKGROUND

Sodium glucose cotransporter 2 inhibitors (SGLT2 inhibitors) prevent heart failure (HF) hospitalizations in patients with type 2 diabetes and improve outcomes in those with HF and reduced ejection fraction, regardless of type 2 diabetes. Mechanisms of HF benefits remain unclear, and the effects of SGLT2 inhibitor on hemodynamics (filling pressures) are not known. The EMBRACE-HF trial (Empagliflozin Evaluation by Measuring Impact on Hemodynamics in Patients With Heart Failure) was designed to address this knowledge gap.

METHODS

EMBRACE-HF is an investigator-initiated, randomized, multicenter, double-blind, placebo-controlled trial. From July 2017 to November 2019, patients with HF (regardless of ejection fraction, with or without type 2 diabetes) and previously implanted pulmonary artery (PA) pressure sensor (CardioMEMS) were randomized across 10 US centers to empagliflozin 10 mg daily or placebo and treated for 12 weeks. The primary end point was change in PA diastolic pressure (PADP) from baseline to end of treatment (average PADP weeks 8-12). Secondary end points included health status (Kansas City Cardiomyopathy Questionnaire score), natriuretic peptides, and 6-min walking distance.

RESULTS

Overall, 93 patients were screened, and 65 were randomized (33 to empagliflozin, 32 to placebo). The mean age was 66 years; 63% were male; 52% had type 2 diabetes; 54% were in New York Heart Association class III/IV; mean ejection fraction was 44%; median NT-proBNP (N-terminal pro B-type natriuretic peptide) was 637 pg/mL; and mean PADP was 22 mm Hg. Empagliflozin significantly reduced PADP, with effects that began at week 1 and amplified over time; average PADP (weeks 8-12) was 1.5 mm Hg lower (95% CI, 0.2-2.8; P=0.02); and at week 12, PADP was 1.7 mm Hg lower (95% CI, 0.3-3.2; P=0.02) with empagliflozin versus placebo. Results were consistent for PA systolic and PA mean pressures. There was no difference in mean loop diuretic management (daily furosemide equivalents) between treatment groups. No significant differences between treatment groups were observed in Kansas City Cardiomyopathy Questionnaire scores, natriuretic peptide levels, and 6-min walking distance.

CONCLUSIONS

In patients with HF and CardioMEMS PA pressure sensor, empagliflozin produced rapid reductions in PA pressures that were amplified over time and appeared to be independent of loop diuretic management. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03030222.

Emerging Pharmacologic Therapies for Heart Failure With Reduced Ejection Fraction

The global burden of heart failure has reached epidemic proportions with tremendous health and economic consequences. Sodium glucose cotransporter 2 inhibitors, vericiguat, and omecamtiv mecarbil are novel agents that promise to blunt the high residual risk of heart failure with reduced ejection fraction. We review the vast knowledge base that has rapidly materialized for these agents and is poised to shape the current and future trends and recommendations in heart failure pharmacotherapy.

Sotagliflozin in Patients with Diabetes and Chronic Kidney Disease

BACKGROUND

The efficacy and safety of sodium-glucose cotransporter 2 inhibitors such as sotagliflozin in preventing cardiovascular events in patients with diabetes with chronic kidney disease with or without albuminuria have not been well studied.

METHODS

We conducted a multicenter, double-blind trial in which patients with type 2 diabetes mellitus (glycated hemoglobin level, ≥7%), chronic kidney disease (estimated glomerular filtration rate, 25 to 60 ml per minute per 1.73 m² of body-surface area), and risks for cardiovascular disease were randomly assigned in a 1:1 ratio to receive sotagliflozin or placebo. The primary end point was changed during the trial to the composite of the total number of deaths from cardiovascular causes, hospitalizations for heart failure, and urgent visits for heart failure. The trial ended early owing to loss of funding.

RESULTS

Of 19,188 patients screened, 10,584 were enrolled, with 5292 assigned to the sotagliflozin group and 5292 assigned to the placebo group, and followed for a median of 16 months. The rate of primary end-point events was 5.6 events per 100 patient-years in the sotagliflozin group and 7.5 events per 100 patient-years in the placebo group (hazard ratio, 0.74; 95% confidence interval [CI], 0.63 to 0.88; P<0.001). The rate of deaths from cardiovascular causes per 100 patient-years was 2.2 with sotagliflozin and 2.4 with placebo (hazard ratio, 0.90; 95% CI, 0.73 to 1.12; P = 0.35). For the original coprimary end point of the first occurrence of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke, the hazard ratio was 0.84 (95% CI, 0.72 to 0.99); for the original coprimary end point of the first occurrence of death from cardiovascular causes or hospitalization for heart failure, the hazard ratio was 0.77 (95% CI, 0.66 to 0.91). Diarrhea, genital mycotic infections, volume depletion, and diabetic ketoacidosis were more common with sotagliflozin than with placebo.

CONCLUSIONS

In patients with diabetes and chronic kidney disease, with or without albuminuria, sotagliflozin resulted in a lower risk of the composite of deaths from cardiovascular causes, hospitalizations for heart failure, and urgent visits for heart failure than placebo but was associated with adverse events. (Funded by Sanofi and Lexicon Pharmaceuticals; SCORED ClinicalTrials.gov number, NCT03315143.).

Sotagliflozin in Patients with Diabetes and Recent Worsening Heart Failure

BACKGROUND

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of hospitalization for heart failure or death from cardiovascular causes among patients with stable heart failure. However, the safety and efficacy of SGLT2 inhibitors when initiated soon after an episode of decompensated heart failure are unknown.

METHODS

We performed a multicenter, double-blind trial in which patients with type 2 diabetes mellitus who were recently hospitalized for worsening heart failure were randomly assigned to receive sotagliflozin or placebo. The primary end point was the total number of deaths from cardiovascular causes and hospitalizations and urgent visits for heart failure (first and subsequent events). The trial ended early because of loss of funding from the sponsor.

RESULTS

A total of 1222 patients underwent randomization (608 to the sotagliflozin group and 614 to the placebo group) and were followed for a median of 9.0 months; the first dose of sotagliflozin or placebo was administered before discharge in 48.8% and a median of 2 days after discharge in 51.2%. Among these patients, 600 primary end-point events occurred (245 in the sotagliflozin group and 355 in the placebo group). The rate (the number of events per 100 patient-years) of primary end-point events was lower in the sotagliflozin group than in the placebo group (51.0 vs. 76.3; hazard ratio, 0.67; 95% confidence interval [CI], 0.52 to 0.85; P<0.001). The rate of death from cardiovascular causes was 10.6 in the sotagliflozin group and 12.5 in the placebo group (hazard ratio, 0.84; 95% CI, 0.58 to 1.22); the rate of death from any cause was 13.5 in the sotagliflozin group and 16.3 in the placebo group (hazard ratio, 0.82; 95% CI, 0.59 to 1.14). Diarrhea was more common with sotagliflozin than with placebo (6.1% vs. 3.4%), as was severe hypoglycemia (1.5% vs. 0.3%). The percentage of patients with hypotension was similar in the sotagliflozin group and the placebo group (6.0% and 4.6%, respectively), as was the percentage with acute kidney injury (4.1% and 4.4%, respectively). The benefits of sotagliflozin were consistent in the prespecified subgroups of patients stratified according to the timing of the first dose.

CONCLUSIONS

In patients with diabetes and recent worsening heart failure, sotagliflozin therapy, initiated before or shortly after discharge, resulted in a significantly lower total number of deaths from cardiovascular causes and hospitalizations and urgent visits for heart failure than placebo. (Funded by Sanofi and Lexicon Pharmaceuticals; SOLOIST-WHF ClinicalTrials.gov number, NCT03521934.).

Cardioprotective mechanism of SGLT2 inhibitor against myocardial infarction is through reduction of autosis

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce cardiovascular mortality in patients with diabetes mellitus but the protective mechanism remains elusive. Here we demonstrated that the SGLT2 inhibitor, Empagliflozin (EMPA), suppresses cardiomyocytes autosis (autophagic cell death) to confer cardioprotective effects. Using myocardial infarction (MI) mouse models with and without diabetes mellitus, EMPA treatment significantly reduced infarct size, and myocardial fibrosis, thereby leading to improved cardiac function and survival. In the context of ischemia and nutritional glucose deprivation where autosis is already highly stimulated, EMPA directly inhibits the activity of the Na⁺/H⁺ exchanger 1 (NHE1) in the cardiomyocytes to regulate excessive autophagy. Knockdown of NHE1 significantly rescued glucose deprivation-induced autosis. In contrast, overexpression of NHE1 aggravated the cardiomyocytes death in response to starvation, which was effectively rescued by EMPA treatment. Furthermore, in vitro and in vivo analysis of NHE1 and Beclin 1 knockout mice validated that EMPA’s cardioprotective effects are at least in part through downregulation of autophagic flux. These findings provide new insights for drug development, specifically targeting NHE1 and autosis for ventricular remodeling and heart failure after MI in both diabetic and non-diabetic patients.

Impact of an SGLT2-loss of function mutation on renal architecture, histology, and glucose homeostasis

Inhibitors of sodium/glucose co-transporter 2 (SGLT2) are currently in clinical use for type 2 diabetes (T2D) treatment due to their anti-hyperglycemic effect exerted by the inhibition of glucose reabsorption in the kidney. Inhibition of SGLT2 is associated with improvement of renal outcomes in chronic kidney disease associated with T2D. Our study aimed to describe the renal-specific phenotypic consequences of the SGLT2-loss of function "Jimbee" mutation within the Slc5a2 mouse gene in a non-diabetic/non-obese background. The Jimbee mice displayed reduced body weight, glucosuria, polyuria, polydipsia, and hyperphagia but were normoglycemic, with no signs of baseline insulin resistance or renal dysfunction. Histomorphological analysis of the kidneys revealed a normal architecture and morphology of the renal cortex, but shrinkage of the glomerular and tubular apparatus, including Bowman's space, glomerular tuft, mesangial matrix fraction, and proximal convoluted tubule (PCT). Immunofluorescent analysis of renal sections showed that SGLT2 was absent from the apical membrane of PCT of the Jimbee mice but remnant positive vesicles were detected within the cytosol or at the perinuclear interface. Renal localization and abundance of GLUT1, GLUT2, and SGLT1 were unchanged in the Jimbee genotype. Intriguingly, the mutation did not induce hepatic gluconeogenic gene expression in overnight fasted mice despite a high glucose excretion rate. The Jimbee phenotype is remarkably similar to humans with SLC5A2 mutations and provides a useful model for the study of SGLT2-loss of function effects on renal architecture and physiology, as well as for identifying possible novel roles for the kidneys in glucose homeostasis and metabolic reprogramming.

Sodium-Glucose Co-Transporter 2 (SGLT2) Inhibitors: Are They All the Same? A Narrative Review of Cardiovascular Outcome Trials

Clinically important improvements in cardiovascular risk factors and adverse cardiovascular, heart failure and renal outcomes have been observed in numerous cardiovascular outcome trials (CVOTs) investigating the use of sodium-glucose co-transporter 2 (SGLT2) inhibitors over the last 5 years. However, differences in study outcomes between the various SGLT2 inhibitor CVOTs are often challenging to interpret because of differences in the study design, participant characteristics and primary outcomes of the various trials. In clinical practice, this frequently challenges the clinician when choosing between the different SGLT2 inhibitors for a patient with type 2 diabetes and various cardiovascular or renal comorbidities. Discussion around the choice of SGLT2 inhibitor has been again revived by the recent publication of results from the VERTIS-CV, EMPEROR-reduced and DAPA-CKD trials investigating cardiovascular, heart failure and renal outcomes associated with various SGLT2 inhibitors.This narrative review gives an overview of the mechanism of action and differences in the underlying pharmacology of the various SGLT2 inhibitors and discusses the key cardiovascular, heart failure and renal outcomes from completed CVOTs for SGLT2 inhibitors. Discussion highlights important differences in the study design and participant characteristics which limit the comparison of trials and medications within this drug class.

Effects and safety of SGLT2 inhibitors compared to placebo in patients with heart failure: A systematic review and meta-analysis

Background

Heart failure (HF) prognosis without therapy is poor, however introduction of a range of drugs has improved it. We aimed to perform a systematic review on the effects and safety of sodium-glucose transporter 2 inhibitors (SGLT2i) in HF patients.

Methods

We carried out a systematic review of randomized controlled trials (RCTs) on SGLT2i compared to placebo for HF patients. We searched in PubMed, Scopus, Web of Science and EMBASE, with no language restriction, from inception to 31 August 2020. We included nine RCTs comprising three arms (empagliflozin, dapagliflozin and placebo). Effects sizes for continuous variables were expressed as mean differences (MDs) and 95% confidence intervals (CIs). Effects sizes for dichotomous variables were expresses as risk ratio (RR) and 95% CIs. We used random-effect models with the inverse variance method. We performed subgroup meta-analyses by intervention drug and follow-up period.

Results

SGLT2i significantly reduced all-cause mortality (RR: 0.88, 95%CI 0.79-0.98, I2 = 0%), cardiovascular mortality (RR: 0.87, 95%CI 0.77-0.99, I2 = 0%), HF hospitalization (RR: 0.73, 95%CI 0.66-0.81, I2 = 0%) and emergency room visits due to HF (RR: 0.40, 95%CI 0.21-0.76, I2 = 0%), as well as composite outcomes including the previous ones. Besides, it significantly improved the score of the Kansas City Cardiomyopathy Questionnaire (KCCQ, MD: 1.70, 95%CI 1.67-1.73, I2 = 54%). SGLT2i reduced any serious adverse events, blood pressure and weight. However, it increased hematocrit and creatinine. The meta-analysis of RCTs of > 12 weeks of follow-up showed that SGTL2i significantly reduced NT-proBNP.

Conclusions

SGLT2i showed to improve critical outcomes in HF patients, and it is apparently safe.

Efficacy and Safety of SGLT-2 Inhibitors for Treatment of Diabetes Mellitus among Kidney Transplant Patients: A Systematic Review and Meta-Analysis

BACKGROUND

The objective of this systematic review was to evaluate the efficacy and safety profiles of sodium-glucose co-transporter 2 (SGLT-2) inhibitors for treatment of diabetes mellitus (DM) among kidney transplant patients.

METHODS

We conducted electronic searches in Medline, Embase, Scopus, and Cochrane databases from inception through April 2020 to identify studies that investigated the efficacy and safety of SGLT-2 inhibitors in kidney transplant patients with DM. Study results were pooled and analyzed utilizing random-effects model.

RESULTS

Eight studies with 132 patients (baseline estimated glomerular filtration rate (eGFR) of 64.5 ± 19.9 mL/min/1.73m2) treated with SGLT-2 inhibitors were included in our meta-analysis. SGLT-2 inhibitors demonstrated significantly lower hemoglobin A1c (HbA1c) (WMD = -0.56% [95%CI: -0.97, -0.16]; p = 0.007) and body weight (WMD = -2.16 kg [95%CI: -3.08, -1.24]; p < 0.001) at end of study compared to baseline level. There were no significant changes in eGFR, serum creatinine, urine protein creatinine ratio, and blood pressure. By subgroup analysis, empagliflozin demonstrated a significant reduction in body mass index (BMI) and body weight. Canagliflozin revealed a significant decrease in HbA1C and systolic blood pressure. In terms of safety profiles, fourteen patients had urinary tract infection. Only one had genital mycosis, one had acute kidney injury, and one had cellulitis. There were no reported cases of euglycemic ketoacidosis or acute rejection during the treatment.

CONCLUSION

Among kidney transplant patients with excellent kidney function, SGLT-2 inhibitors for treatment of DM are effective in lowering HbA1C, reducing body weight, and preserving kidney function without reporting of serious adverse events, including euglycemic ketoacidosis and acute rejection.

Effect of Empagliflozin on Cardiovascular and Renal Outcomes in Patients With Heart Failure by Baseline Diabetes Status: Results From the EMPEROR-Reduced Trial

Supplemental Digital Content is available in the text.

Sodium-glucose cotransporter 2 inhibitors improve outcomes in patients with heart failure with reduced ejection fraction, but additional information is needed about whether glycemic status influences the magnitude of their benefits on heart failure and renal events.

Critical Role for AMPK in Metabolic Disease-Induced Chronic Kidney Disease

Chronic kidney disease (CKD) is prevalent in 9.1% of the global population and is a significant public health problem associated with increased morbidity and mortality. CKD is associated with highly prevalent physiological and metabolic disturbances such as hypertension, obesity, insulin resistance, cardiovascular disease, and aging, which are also risk factors for CKD pathogenesis and progression. Podocytes and proximal tubular cells of the kidney strongly express AMP-activated protein kinase (AMPK). AMPK plays essential roles in glucose and lipid metabolism, cell survival, growth, and inflammation. Thus, metabolic disease-induced renal diseases like obesity-related and diabetic chronic kidney disease demonstrate dysregulated AMPK in the kidney. Activating AMPK ameliorates the pathological and phenotypical features of both diseases. As a metabolic sensor, AMPK regulates active tubular transport and helps renal cells to survive low energy states. AMPK also exerts a key role in mitochondrial homeostasis and is known to regulate autophagy in mammalian cells. While the nutrient-sensing role of AMPK is critical in determining the fate of renal cells, the role of AMPK in kidney autophagy and mitochondrial quality control leading to pathology in metabolic disease-related CKD is not very clear and needs further investigation. This review highlights the crucial role of AMPK in renal cell dysfunction associated with metabolic diseases and aims to expand therapeutic strategies by understanding the molecular and cellular processes underlying CKD.

Cardiovascular and Renal Outcomes with Empagliflozin in Heart Failure

BACKGROUND

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of hospitalization for heart failure in patients regardless of the presence or absence of diabetes. More evidence is needed regarding the effects of these drugs in patients across the broad spectrum of heart failure, including those with a markedly reduced ejection fraction.

METHODS

In this double-blind trial, we randomly assigned 3730 patients with class II, III, or IV heart failure and an ejection fraction of 40% or less to receive empagliflozin (10 mg once daily) or placebo, in addition to recommended therapy. The primary outcome was a composite of cardiovascular death or hospitalization for worsening heart failure.

RESULTS

During a median of 16 months, a primary outcome event occurred in 361 of 1863 patients (19.4%) in the empagliflozin group and in 462 of 1867 patients (24.7%) in the placebo group (hazard ratio for cardiovascular death or hospitalization for heart failure, 0.75; 95% confidence interval [CI], 0.65 to 0.86; P<0.001). The effect of empagliflozin on the primary outcome was consistent in patients regardless of the presence or absence of diabetes. The total number of hospitalizations for heart failure was lower in the empagliflozin group than in the placebo group (hazard ratio, 0.70; 95% CI, 0.58 to 0.85; P<0.001). The annual rate of decline in the estimated glomerular filtration rate was slower in the empagliflozin group than in the placebo group (-0.55 vs. -2.28 ml per minute per 1.73 m² of body-surface area per year, P<0.001), and empagliflozin-treated patients had a lower risk of serious renal outcomes. Uncomplicated genital tract infection was reported more frequently with empagliflozin.

CONCLUSIONS

Among patients receiving recommended therapy for heart failure, those in the empagliflozin group had a lower risk of cardiovascular death or hospitalization for heart failure than those in the placebo group, regardless of the presence or absence of diabetes. (Funded by Boehringer Ingelheim and Eli Lilly; EMPEROR-Reduced ClinicalTrials.gov number, NCT03057977.).

Characterization of left ventricular myocardial sodium-glucose cotransporter 1 expression in patients with end-stage heart failure

Background

Whereas selective sodium-glucose cotransporter 2 (SGLT2) inhibitors consistently showed cardiovascular protective effects in large outcome trials independent of the presence of type 2 diabetes mellitus (T2DM), the cardiovascular effects of dual SGLT1/2 inhibitors remain to be elucidated. Despite its clinical relevance, data are scarce regarding left ventricular (LV) SGLT1 expression in distinct heart failure (HF) pathologies. We aimed to characterize LV SGLT1 expression in human patients with end-stage HF, in context of the other two major glucose transporters: GLUT1 and GLUT4.

Methods

Control LV samples (Control, n = 9) were harvested from patients with preserved LV systolic function who went through mitral valve replacement. LV samples from HF patients undergoing heart transplantation (n = 71) were obtained according to the following etiological subgroups: hypertrophic cardiomyopathy (HCM, n = 7); idiopathic dilated cardiomyopathy (DCM, n = 12); ischemic heart disease without T2DM (IHD, n = 14), IHD with T2DM (IHD + T2DM, n = 11); and HF patients with cardiac resynchronization therapy (DCM:CRT, n = 9, IHD:CRT, n = 9 and IHD-T2DM:CRT, n = 9). We measured LV SGLT1, GLUT1 and GLUT4 gene expressions with qRT-PCR. The protein expression of SGLT1, and activating phosphorylation of AMP-activated protein kinase (AMPKα) and extracellular signal-regulated kinase 1/2 (ERK1/2) were quantified by western blotting. Immunohistochemical staining of SGLT1 was performed.

Results

Compared with controls, LV SGLT1 mRNA and protein expressions were significantly and comparably upregulated in HF patients with DCM, IHD and IHD + T2DM (all P < 0.05), but not in HCM. LV SGLT1 mRNA and protein expressions positively correlated with LVEDD and negatively correlated with EF (all P < 0.01). Whereas AMPKα phosphorylation was positively associated with SGLT1 protein expression, ERK1/2 phosphorylation showed a negative correlation (both P < 0.01). Immunohistochemical staining revealed that SGLT1 expression was predominantly confined to cardiomyocytes, and not fibrotic tissue. Overall, CRT was associated with reduction of LV SGLT1 expression, especially in patients with DCM.

Conclusions

Myocardial LV SGLT1 is upregulated in patients with HF (except in those with HCM), correlates significantly with parameters of cardiac remodeling (LVEDD) and systolic function (EF), and is downregulated in DCM patients with CRT. The possible role of SGLT1 in LV remodeling needs to be elucidated.

Mutual Antagonism of Hypoxia-Inducible Factor Isoforms in Cardiac, Vascular, and Renal Disorders

Hypoxia-inducible factor (HIF)-1α and HIF-2α promote cellular adaptation to acute hypoxia, but during prolonged activation, these isoforms exert mutually antagonistic effects on the redox state and on proinflammatory pathways. Sustained HIF-1α signaling can increase oxidative stress, inflammation, and fibrosis, actions that are opposed by HIF-2α. Imbalances in the interplay between HIF-1α and HIF-2α may contribute to the progression of chronic heart failure, atherosclerotic and hypertensive vascular disorders, and chronic kidney disease. These disorders are characterized by activation of HIF-1α and suppression of HIF-2α, which are potentially related to mitochondrial and peroxisomal dysfunction and suppression of the redox sensor, sirtuin-1. Hypoxia mimetics can potentiate HIF-1α and/or HIF-2α; ideally, such agents should act preferentially to promote HIF-2α while exerting little effect on or acting to suppress HIF-1α. Selective activation of HIF-2α can be achieved with drugs that: 1) inhibit isoform-selective prolyl hydroxylases (e.g., cobalt chloride and roxadustat); or 2) promote the actions of the redox sensor, sirtuin-1 (e.g., sodium-glucose cotransporter 2 inhibitors). Selective HIF-2α signaling through sirtuin-1 activation may explain the effect of sodium-glucose cotransporter 2 inhibitors to simultaneously promote erythrocytosis and ameliorate the development of cardiomyopathy and nephropathy.

Intermittent fasting and 'metabolic switch': Effects on metabolic syndrome, prediabetes and type 2 diabetes

Various intermittent fasting (IF) dietary plans have gained popularity among obese individuals in recent years as a means of achieving weight loss. However, studies evaluating the effect of IF regimens in people with metabolic syndrome, prediabetes and type 2 diabetes (T2D) are limited. The aim of the present review was to briefly elucidate the biochemical and physiological mechanisms underlying the positive effects of IF, especially the effect of the proposed 'metabolic switch' on metabolism. Next, we examined the efficacy and safety of IF regimens in individuals with metabolic syndrome, prediabetes and T2D. To achieve this, we performed a MEDLINE PubMed search using combinations of various IF terms, including trials in which participants met the additional criteria for metabolic syndrome, prediabetes or T2D. We found four studies in individuals with metabolic syndrome, one study in people with prediabetes, and eight studies in people with T2D evaluating the effects of different IF regimens. The limited available evidence, with small sample sizes and short trial durations, suggests that IF regimens have a similar effectiveness compared with calorie-restriction diets for weight loss and improvement in glycaemic variables. In general, most IF regimens are effective and safe. However, there is an increased risk of hypoglycaemia in patients with T2D who are treated with insulin or sulphonylureas. Moreover, long-term adherence to these regimens appears uncertain. There is a need for large controlled randomized trials to evaluate the efficacy of IF regimens, especially in individuals with metabolic syndrome and prediabetes. If proven to be sustainable and efficacious for prolonged periods, IF could offer a promising approach to improving health at the population level, and would result in multiple public health benefits.

Are SGLT-2 Inhibitors the Future of Heart Failure Treatment? The EMPEROR-Preserved and EMPEROR-Reduced Trials

Heart failure is frequently associated with diabetes, and therapies which reduce mortality in people with heart failure and reduced ejection fraction (HFrEF) are often limited to drugs which modulate the renin-angiotensin-aldosterone system or heart rate control and occasionally to device therapy. Treatment is even more challenging in people with heart failure and preserved ejection fraction (HFpEF), with currently no approved therapy demonstrating a mortality-improving effect, limiting treatment to diuretics for the alleviation of the symptoms of fluid overload and risk factor management. Previous cardiovascular outcome trials for sodium-glucose co-transporter-2 (SGLT-2) inhibitors have demonstrated significant favourable outcomes for cardiovascular disease, heart failure hospitalisation and all-cause mortality. The aim of the nearly completed EMPEROR-preserved and EMPEROR-reduced trials is to determine the impact of empagliflozin on cardiovascular and heart failure outcomes in people with HFpEF or HFrEF with or without diabetes. The trials will add substantially to our understanding of SGLT-2 inhibitors in the treatment of HFrEF and may have major implications for the treatment of people with HFpEF. The study will also be powered to address the impact of empagliflozin on changes in renal function in people with and without diabetes and incident diabetes in the participants without diabetes at baseline. In this article we discuss the rationale for using SGLT-2 inhibitors in people with heart failure and explore the potential findings and importance of the ongoing EMPEROR-preserved and EMPEROR-reduced trials.

Range of adiposity and cardiorenal syndrome

Obesity and obesity-related co-morbidities, diabetes mellitus, and hypertension are among the fastest-growing risk factors of heart failure and kidney disease worldwide. Obesity, which is not a unitary concept, or a static process, ranges from alterations in distribution to the amount of adiposity. Visceral adiposity, which includes intraabdominal visceral fat mass and ectopic fat deposition such as hepatic, cardiac, or renal, was robustly associated with a greater risk for cardiorenal morbidity than subcutaneous adiposity. In addition, morbid obesity has also demonstrated a negative effect on cardiac and renal functioning. The mechanisms by which adipose tissue is linked with the cardiorenal syndrome (CRS) are hemodynamic and mechanical changes, as well neurohumoral pathways such as insulin resistance, endothelial dysfunction, nitric oxide bioavailability, renin-angiotensin-aldosterone, oxidative stress, sympathetic nervous systems, natriuretic peptides, adipokines and inflammation. Adiposity and other associated co-morbidities induce adverse cardiac remodeling and interstitial fibrosis. Heart failure with preserved ejection fraction has been associated with obesity-related functional and structural abnormalities. Obesity might also impair kidney function through hyperfiltration, increased glomerular capillary wall tension, and podocyte dysfunction, which leads to tubulointerstitial fibrosis and loss of nephrons and, finally, chronic kidney disease. The development of new treatments with renal and cardiac effects in the context of type 2 diabetes, which improves mortality outcome, has highlighted the importance of CRS and its prevalence. Increased body fat triggers cellular, neuro-humoral and metabolic pathways, which create a phenotype of the CRS with specific cellular and biochemical biomarkers. Obesity has become a single cardiorenal umbrella or type of cardiorenal metabolic syndrome. This review article provides a clinical overview of the available data on the relationship between a range of adiposity and CRS, the support for obesity as a single cardiorenal umbrella, and the most relevant studies on the recent therapeutic approaches.

NAFLD and cardiovascular diseases: a clinical review

Non-alcoholic fatty liver DISEASE (NAFLD) is the most common chronic liver disease in Western countries and affects approximately 25% of the adult population. Since NAFLD is frequently associated with further metabolic comorbidities such as obesity, type 2 diabetes mellitus, or dyslipidemia, it is generally considered as the hepatic manifestation of the metabolic syndrome. In addition to its potential to cause liver-related morbidity and mortality, NAFLD is also associated with subclinical and clinical cardiovascular disease (CVD). Growing evidence indicates that patients with NAFLD are at substantial risk for the development of hypertension, coronary heart disease, cardiomyopathy, and cardiac arrhythmias, which clinically result in increased cardiovascular morbidity and mortality. The natural history of NAFLD is variable and the vast majority of patients will not progress from simple steatosis to fibrosis and end stage liver disease. However, patients with progressive forms of NAFLD, including non-alcoholic steatohepatitis (NASH) and/or advanced fibrosis, as well as NAFLD patients with concomitant types 2 diabetes are at highest risk for CVD. This review describes the underlying pathophysiological mechanisms linking NAFLD and CVD, discusses the role of NAFLD as a metabolic dysfunction associated cardiovascular risk factor, and focuses on common cardiovascular manifestations in NAFLD patients.

CREDENCE: Significant Victory for Diabetic Kidney Disease

Diabetic kidney disease (DKD), the most common cause of end-stage kidney disease (ESKD), has significant morbidity and mortality, particularly from cardiovascular complications. The CREDENCE (canagliflozin and renal events in diabetes with established nephropathy clinical evaluation) trial reported by Perkovic and collaborators has led to an emergence of a new class of therapeutic agents for slowing DKD progression.

Comparative Analysis of the Preventive Effects of Canagliflozin, a Sodium-Glucose Co-Transporter-2 Inhibitor, on Body Weight Gain Between Oral Gavage and Dietary Administration by Focusing on Fatty Acid Metabolism

PURPOSE

Sodium-glucose co-transporter-2 (SGLT2) inhibitors have various pleiotropic effects, including body weight reduction, and therefore have the potential to be used in various applications. However, such effects have not been fully investigated; thus, non-clinical studies using animal models are needed. In animal experiments, SGLT2 inhibitors are usually administered by oral or dietary methods. However, the detailed characteristics of these dosing methods, especially to induce their pleiotropic effects, have not been reported. Therefore, we compared the preventive effects of canagliflozin, an SGLT2 inhibitor, on body weight gain following oral gavage and dietary administration methods in a mouse model of diet-induced obesity.

METHODS

Canagliflozin was dosed by oral gavage or dietary administration for 9 weeks to 6-week-old C57BL/6N mice fed a high-fat diet, and parameters related to obesity were evaluated.

RESULTS

The suppression of body weight gain, fat mass, and hepatic lipid content was observed following both dosing methods, whereas the effect on body weight tended to be stronger in the dietary administration group. In adipose tissue, fatty acid synthase expression was significantly decreased in the dietary administration group, and its expression was significantly correlated with fat mass. However, the expression of genes related to fatty acid oxidation was unchanged, indicating that the preventive effect on body weight gain was mediated mainly through the suppression of lipid synthesis rather than the promotion of lipid oxidation.

CONCLUSION

Canagliflozin prevented body weight gain through the suppression of lipid synthesis via both dosing methods, although there were some differences in the efficacy. The findings of our study can help to identify new mechanisms of action of SGLT2 inhibitors and potential applications.