Mechanisms of cardio-renal protection of sodium-glucose cotransporter-2 inhibitors

Impact of Dapagliflozin on Hepatic Lipid Metabolism and a Dynamic Model of Ketone Body Levels

The rising prevalence of metabolic-associated steatotic liver disease emphasizes the need to understand its lipid metabolism. Dapagliflozin may improve hepatic steatosis but could also increase the risk of ketoacidosis by elevating β-hydroxybutyrate (KB) levels. This study investigates dapagliflozin's effects on hepatic lipid metabolism and quantifies KB levels in vivo. Male Sprague-Dawley rats were fed either a normal diet or a high-fat diet (HFD) for 12 weeks. The HFD rats were then divided into four subgroups to receive vehicle, 0.5 mg/kg, 1 mg/kg, and 3 mg/kg of dapagliflozin for four weeks. Free fatty acids (FFA) and KB levels were monitored, while protein and gene expression were analyzed. And a dynamic model of KB was developed for humans based on preclinical data. Dapagliflozin decreased body weight and visceral fat in HFD rats, increasing KB by upregulating CPT1a, HMGCS2, and HMGCL, and downregulating ACC. These changes correlated with reduced liver/fat index, liver pathology score, and oil-red staining area. A pharmacokinetic/pharmacodynamic (PK/PD) model was created from preclinical data to quantify KB levels in rats and validated in humans. Dapagliflozin reduces hepatic steatosis by enhancing fatty acid β-oxidation and ketogenesis and inhibiting fat synthesis. A dynamic model accurately predicts ketone body levels in treated individuals.

Clinical efficacy and cost-effectiveness of metformin in different patient populations: A narrative review of real-world evidence

Over the past two decades, diabetes pharmacopoeia has flourished, with new drugs that, on top of their glucose-lowering efficacy, have been shown to protect the heart and the kidney. Despite these new opportunities, metformin retains a pivotal role among glucose-lowering agents. As one of the few available insulin sensitizers, metformin is an effective, safe, and overall well-tolerated drug backed by over 60 years of clinical experience, including evidence for potential benefits beyond glucose reduction across different ages, sexes, genetic backgrounds, geographical areas, and stages of disease. Although there is some discussion of whether metformin offers the most effective front-line option in newly diagnosed type 2 diabetes (T2D), it remains a natural companion to all other glucose-lowering agents. Furthermore, metformin comes at a very low cost and, as such, it has extremely high cost-effectiveness, particularly given the serious economic burden associated with diabetes complications. This financial advantage is particularly relevant in resource-constrained healthcare systems, where the affordability of metformin may be instrumental in implementing an effective treatment in an evergrowing number of individuals. We present here compelling real-world evidence in support of the clinical efficacy and cost-effectiveness of metformin across different patient populations, highlighting areas where more population-based studies are needed to further incorporate and consolidate its use in the pharmacological management of T2D.

Genitourinary Tract Infections in Patients Taking SGLT2 Inhibitors: JACC Review Topic of the Week

Sodium-glucose cotransporter-2 inhibitors (SGLT2is) have been shown to reduce adverse cardiovascular events in patients with type 2 diabetes mellitus, all-cause mortality, and heart failure hospitalization in patients with heart failure, as well as adverse renal outcomes. However, concerns regarding the heightened risk of genitourinary (GU) infections, particularly urinary tract infections, remain a significant barrier to their wider adoption. Addressing these misconceptions using existing evidence is needed to ensure proper risk-benefit assessment and optimal utilization of this efficacious therapy. This review aims to provide a balanced perspective on the evidence-based cardiovascular and renal benefits of SGLT2is and the associated risk of GU infections. We also summarize and propose clinical practice considerations for SGLT2i-associated GU infections focusing on patients with cardiovascular disease.

Pathophysiological Rationale and Clinical Evidence for Neurohormonal Modulation in Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous syndrome resulting from the interaction between cardiac diseases, comorbidities and ageing. HFpEF is characterised by the activation of neurohormonal axes, namely of the renin-angiotensin-aldosterone system and the sympathetic nervous system, although to a lesser extent compared with heart failure with reduced ejection fraction. This provides a rationale for neurohormonal modulation as a therapeutic approach for HFpEF. Nonetheless, randomised clinical trials have failed to demonstrate a prognostic benefit from neurohormonal modulation therapies in HFpEF, with the sole exception of patients with left ventricular ejection fraction in the lower range of normality, for whom the American guidelines suggest that such therapies may be considered. In this review, the pathophysiological rationale for neurohormonal modulation in HFpEF is summarised and the clinical evidence on pharmacological and nonpharmacological approaches backing current recommendations discussed.

Empagliflozin reduces arrhythmogenic effects in rat neonatal and human iPSC-derived cardiomyocytes and improves cytosolic calcium handling at least partially independent of NHE1

The antidiabetic agent class of sodium-glucose cotransporter 2 (SGLT2) inhibitors confer unprecedented cardiovascular benefits beyond glycemic control, including reducing the risk of fatal ventricular arrhythmias. However, the impact of SGLT2 inhibitors on the electrophysiological properties of cardiomyocytes exposed to stimuli other than hyperglycemia remains elusive. This investigation tested the hypothesis that the SGLT2 inhibitor empagliflozin (EMPA) affects cardiomyocyte electrical activity under hypoxic conditions. Rat neonatal and human induced pluripotent stem cell (iPSC)-derived cardiomyocytes incubated or not with the hypoxia-mimetic agent CoCl₂ were treated with EMPA (1 μM) or vehicle for 24 h. Action potential records obtained using intracellular microelectrodes demonstrated that EMPA reduced the action potential duration at 30%, 50%, and 90% repolarization and arrhythmogenic events in rat and human cardiomyocytes under normoxia and hypoxia. Analysis of Ca²⁺ transients using Fura-2-AM and contractility kinetics showed that EMPA increased Ca²⁺ transient amplitude and decreased the half-time to recover Ca²⁺ transients and relaxation time in rat neonatal cardiomyocytes. We also observed that the combination of EMPA with the Na⁺/H⁺ exchanger isoform 1 (NHE1) inhibitor cariporide (10 µM) exerted a more pronounced effect on Ca²⁺ transients and contractility than either EMPA or cariporide alone. Besides, EMPA, but not cariporide, increased phospholamban phosphorylation at serine 16. Collectively, our data reveal that EMPA reduces arrhythmogenic events, decreases the action potential duration in rat neonatal and human cardiomyocytes under normoxic or hypoxic conditions, and improves cytosolic calcium handling at least partially independent of NHE1. Moreover, we provided further evidence that SGLT2 inhibitor-mediated cardioprotection may be partly attributed to its cardiomyocyte electrophysiological effects.

Synergistic effect of chronic kidney disease, neuropathy, and retinopathy on all-cause mortality in type 1 and type 2 diabetes: a 21-year longitudinal study

Background

The prognostic value of common and frequently associated diabetic microvascular complications (MVC), namely chronic kidney disease (CKD), cardiac autonomic neuropathy (CAN), peripheral neuropathy (DPN), and retinopathy (DR), is well established. However, the impact of their different combinations on long-term mortality has not been adequately assessed.

Methods

We retrospectively analyzed 21-year longitudinal data from 303 patients with long-standing type 1 (T1D) or type 2 diabetes (T2D), who were thoroughly characterized at baseline for the presence of MVC using 99mTc-DTPA dynamic renal scintigraphy, overnight urine collection, cardiovascular autonomic tests, monofilament testing, and dilated fundus oculi examination.

Results

After a 5,244 person-years follow-up, a total of 133 (43.9%) deaths occurred. The presence of CKD and CAN, regardless of other MVC, increased the adjusted all-cause mortality risk by 117% (HR 2.17 [1.45–3.26]) and 54% (HR 1.54 [1.01–2.36]), respectively. Concomitant CKD&CAN at baseline were associated with the highest mortality risk (HR 5.08 [2.52–10.26]), followed by CKD&DR (HR 2.95 [1.63–5.32]), and CAN&DR (HR 2.07 [1.11–3.85]). Compared with patients free from MVC, the mortality risk was only numerically higher in those with any isolated MVC (HR 1.52 [0.87–2.67]), while increased by 203% (HR 3.03 [1.62–5.68]) and 692% (HR 7.92 [2.93–21.37]) in patients with two and three concomitant MVC, respectively.

Conclusions

Our study demonstrates the long-term, synergistic, negative effects of single and concomitant diabetic MVC on all-cause mortality, which should encourage comprehensive screenings for MCV in both T1D and T2D to improve risk stratification and treatment.