Evolving understanding of cardiovascular protection by SGLT2 inhibitors: focus on renal protection, myocardial effects, uric acid, and magnesium balance

Case report: Two novel compound heterozygous variant of SLC12A3 gene in a gitelman syndrome family and literature review

A 36-year-old unmarried male chef was incidentally diagnosed with hypokalemia during an evaluation for an acute perianal abscess. Despite potassium supplementation, he developed progressive weakness in his lower limbs, culminating in an inability to stand. Investigations confirmed severe hypokalemia, metabolic alkalosis, hypomagnesemia, secondary hyperaldosteronism, and low urinary calcium excretion, with normotension. The patient's long-standing stunted growth and lean physique since childhood were noted. Biochemical assays further identified type 2 diabetes mellitus and metabolic syndrome. Genetic analysis revealed three heterozygous SLC12A3 mutations (M1: c.421G>A: p.G141R, M2: c.509T>A:p.L170Q, and M3: c.704C>A: p.T235K), compound heterozygo us and derived from both parents, with M1 and M3 reported here for the first time. Treatment with spironolactone and oral potassium chloride stabilized his potassium levels. Following the administration of SGLT2 inhibitors in patients receiving hypoglycemic therapy, we observed a mild decrease in serum sodium levels. This case highlights the criticality of vigilant metabolic surveillance in Gitelman syndrome and advises prudence with SGLT2 inhibitors in those with concurrent type 2 diabetes, given the risk of potentially aggravate sodium loss.

Magnesium in hypertension: mechanisms and clinical implications

Hypertension is associated with increased risk of cardiovascular disease and death. Evidence suggests that Mg2+ depletion contributes to hypertension. It is estimated that 25% or more of the United States population experiences chronic, latent Mg2+ depletion. This review explores mechanisms by which Mg2+ influences blood pressure, modifying risk of hypertension and complicating its treatment. Mechanisms addressed include effects upon i) sympathetic tone, via the modulation of N-methyl-D-aspartate (NMDA) receptor and N-type Ca2+ channel activity, influencing catecholamine release from sympathetic nerve endings; ii) vascular tone, via alteration of L-type Ca2+ and endothelial nitric oxide synthase (eNOS) activity and prostacyclin release; iii) renal K+ handling, influencing systemic K+ balance and potentially indirectly influencing blood pressure; iv) aldosterone secretion from the adrenal cortex; and v) modulation of pro-hypertensive inflammatory processes in dendritic cells and macrophages, including activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome and stimulation of isolevuglandin (IsoLG) production. Discovery of these mechanisms has furthered our understanding of the pathogenesis of hypertension, with implications for treatment and has highlighted the role of Mg2+ balance in hypertension and cardiovascular disease.

Drug Safety Evaluation of Sodium-Glucose Cotransporter 2 Inhibitors in Diabetic Comorbid Patients by Review of Systemic Extraglycemic Effects

Purpose

The aim of this study is to evaluate the safety of this drug in diabetic patients with comorbidities of all systems.

Method

In this review, the beneficial effects of this drug and its mechanism on the disorders of every system of humans in relation to diabetes have been studied, and finally, its adverse effects have also been discussed. The search for relevant information is carried out in the PubMed and Google Scholar databases by using the following terms: diabetes mellitus type 2, SGLT, SGLT2 inhibitors, (SGLT2 inhibitors) AND (Pleiotropic effects). All English-published articles from 2016 to 2023 have been used in this study. It should be noted that a small number of articles published before 2016 have been used in the introduction and general informations.

Results

Its beneficial effects on improving cardiovascular disease risk factors and reducing adverse events caused by cardiovascular and renal diseases have proven in most large clinical studies that these effects are almost certain. It also has beneficial effects on other human systems such as the respiratory system, the gastrointestinal system, the circulatory system, and the nervous system; more of them are at the level of clinical and pre-clinical trials but have not been proven in large clinical trials or meta-analyses.

Conclusion

With the exception of a few adverse effects, this drug is considered a good choice and safe for all diabetic patients with comorbidities of all systems.

Searching in the maze: sodium-glucose cotransporter-2 inhibitors in kidney transplant recipients to improve survival

Sodium-glucose cotransporter-2 inhibitors (SGLT2is) improve cardiovascular and renal outcomes in chronic kidney disease patients with and without diabetes. Kidney transplant recipients have been excluded from landmark trials using SGLT2is and literature on safety and efficacy are scarce. Recent studies suggest that the SGLT2i use in kidney transplant recipients with diabetes is safe, paving the way to investigate whether SGLT2is could also reduce cardiovascular events and kidney function deterioration in kidney allograft recipients.

Sodium-glucose cotransporter 2 inhibitors and heart failure: the best timing for the right patient

Sodium-glucose cotransporter 2 inhibitors (SGLT2i), initially born as anti-diabetic drugs, have shown many beneficial effects on the cardiovascular system, in particular against heart failure (HF). HF is a complex and multifaceted disease that requires a comprehensive approach. It should not be considered as a simplistic cardiac disease, but a systemic disease that leads to multisystemic organ failure and death. Exploiting their pleiotropic effects, SGLT2i are a very valid tool for HF treatment. Beyond the indication to reduce HF hospitalization and death risk, in patients with diabetes mellitus at high cardiovascular risk or with established cardiovascular event, SGLT2i administration reported beneficial effects regarding the wide spectrum of HF manifestations and stages, independently by diabetes mellitus presence. Recent evidence focuses on HF rehospitalization, cardiac and all-cause death reduction, as well as symptoms and quality of life improvement, in patients with chronic HF or with a recent HF decompensation episode. Given the recent finding about the SGLT2i usefulness in HF patients, further studies are needed to define the best administration timing to maximize the SGLT2i-derived beneficial effects.

Home Subcutaneous Magnesium Infusion in Refractory Hypomagnesemia: A Case Report

We describe a patient with renal magnesium wasting and prolonged, symptomatic hypomagnesemia that was refractory to oral therapies and intermittent intravenous infusion who achieved near-normal serum magnesium levels with subcutaneous magnesium infusions. A woman in her 40s was seen in nephrology clinic for evaluation and management of severe, chronic hypomagnesemia because of renal magnesium wasting in combination with frequent diarrhea. Clinical manifestations associated with hypomagnesemia included muscle weakness, cognitive impairment, and frequent seizures. Her hypomagnesemia had persisted for more than 20 years despite maximal oral magnesium supplementation and frequent intravenous magnesium infusions. To provide slower delivery of parenteral magnesium, she was prescribed 2 g/d of magnesium sulfate, delivered subcutaneously. This was well tolerated, rapidly normalized her serum magnesium levels, and improved her symptoms. We briefly discuss modalities used for treatment of hypomagnesemia, including shortcomings of intravenous therapy and limited literature discussing efficacy and tolerability of subcutaneous infusions. This case report demonstrates the efficacy and safety of subcutaneous magnesium infusions in a patient with refractory hypomagnesemia and suggests that subcutaneous infusion may be safe and effective for treatment of refractory hypomagnesemia in other patients with urinary magnesium wasting.

Physiology of a Forgotten Electrolyte-Magnesium Disorders

Magnesium (Mg²⁺) is the second most common intracellular cation and the fourth most abundant element on earth. However, Mg²⁺ is a frequently overlooked electrolyte and often not measured in patients. While hypomagnesemia is common in 15% of the general population, hypermagnesemia is typically only found in preeclamptic women after Mg²⁺ therapy and in patients with ESRD. Mild to moderate hypomagnesemia has been associated with hypertension, metabolic syndrome, type 2 diabetes mellitus, CKD, and cancer. Nutritional Mg²⁺ intake and enteral Mg²⁺ absorption are important for Mg²⁺ homeostasis, but the kidneys are the key regulators of Mg²⁺ homeostasis by limiting urinary excretion to less than 4% while the gastrointestinal tract loses over 50% of the Mg²⁺ intake in the feces. Here, we review the physiological relevance of Mg²⁺, the current knowledge of Mg²⁺ absorption in the kidneys and the gut, the different causes of hypomagnesemia, and a diagnostic approach on how to assess Mg²⁺ status. We highlight the latest discoveries of monogenetic conditions causing hypomagnesemia, which have enhanced our understanding of tubular Mg²⁺ absorption. We will also discuss external and iatrogenic causes of hypomagnesemia and advances in the treatment of hypomagnesemia.

Comparative Efficacy of Dapagliflozin and Empagliflozin of a Fixed Dose in Heart Failure: A Network Meta-Analysis

Background

The efficacy of dapagliflozin and empagliflozin in sodium-glucose cotransport-2 inhibitors (SGLT-2i) in patients with heart failure (HF) has been discovered. However, which drug could improve varied prognostic outcomes has not been elucidated. Hence, we compared their efficacies on the prognostic improvement of HF.

Methods

Databases including PubMed, EMBASE, Scopus, Google Scholars, and the Cochrane Library were searched for all related randomized controlled trials (RCTs) published from inception to 13 October 2021. Network meta-analyses were performed to generate matrices to show the effect size for pairwise comparison regarding all the interventions.

Results

Eventually a total of 11 RCTs were included in this study. For the primary endpoints, dapagliflozin was comparable with empagliflozin in hospitalization for HF, and empagliflozin (OR=0.70, 95%CI: 0.59–0.84) decreased the risk of exacerbation of HF over dapagliflozin. For the secondary endpoints, dapagliflozin was comparable with empagliflozin in cardiovascular (CV) death /hospitalization for HF, and for CV death, dapagliflozin (OR=0.78, 95%CI: 0.65–0.92) significantly reduced mortality over the placebo. For the tertiary endpoints, dapagliflozin (OR=0.80, 95%CI: 0.66–0.98) significantly decreased the mortality over empagliflozin in all-cause death, and neither drug significantly increased the risk of hypoglycemia.

Recommendations

Overall, 10 mg/day dapagliflozin may be the optimal recommendation for its premium and comprehensive effect on improving the prognosis of patients with HF compared to 10 mg/day empagliflozin.

Comparative Effects of Sodium-Glucose Cotransporter 2 Inhibitors on Serum Electrolyte Levels in Patients with Type 2 Diabetes: A Pairwise and Network Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Previous studies have reported that sodium-glucose co-transporter 2 (SGLT2) inhibitors (SGLT2is) affect levels of serum electrolytes, especially magnesium. This study aimed to integrate direct and indirect trial evidence to maximize statistical power to clarify their overall and comparative effects in patients with type 2 diabetes (T2D).

METHODS

We systematically searched PubMed, EMBASE, CENTRAL, and ClinicalTrials.gov up to January 2021 to identify eligible randomized controlled trials (RCTs) of SGLT2is that reported mean changes in serum electrolytes, including magnesium, sodium, potassium, phosphate, and calcium. We performed both random-effects pairwise and network meta-analyses to calculate the weighted mean difference (WMD) and 95% confidence intervals (CI).

RESULTS

In total, we included 25 RCTs involving 28,269 patients with T2D and 6 SGLT2is. Compared with placebo, SGLT2is were significantly associated with elevations in serum magnesium by 0.07 mmol/L (95% CI, 0.06 to 0.08 mmol/L) and serum phosphate by 0.03 mmol/L (95% CI, 0.02 to 0.04 mmol/L). Our network meta-analysis showed no evidence of significantly superior efficacy of any specific SGLT2 inhibitor over the others, although dapagliflozin was associated with a larger increment in serum magnesium (WMD=0.16 mmol/L) compared with other SGLT2is. Similarly, no statistically detectable differences among the effects of SGLT2is on serum levels of other electrolytes were detected.

CONCLUSIONS

SGLT2is significantly increased serum magnesium and phosphate levels, consistent with a class effect of SGLT2 inhibition. However, further investigations of long-term efficacy and safety in patients with T2D with different clinical phenotypes are needed.

Sodium Glucose Cotransporter-2 Inhibitors: Spotlight on Favorable Effects on Clinical Outcomes beyond Diabetes

Sodium glucose transporter type 2 (SGLT2) molecules are found in proximal tubules of the kidney, and perhaps in the brain or intestine, but rarely in any other tissue. However, their inhibitors, intended to improve diabetes compensation, have many more beneficial effects. They improve kidney and cardiovascular outcomes and decrease mortality. These benefits are not limited to diabetics but were also found in non-diabetic individuals. The pathophysiological pathways underlying the treatment success have been investigated in both clinical and experimental studies. There have been numerous excellent reviews, but these were mostly restricted to limited aspects of the knowledge. The aim of this review is to summarize the known experimental and clinical evidence of SGLT2 inhibitors' effects on individual organs (kidney, heart, liver, etc.), as well as the systemic changes that lead to an improvement in clinical outcomes.

Empagliflozin protects glomerular endothelial cell architecture in experimental diabetes through the VEGF-A/caveolin-1/PV-1 signaling pathway

In addition to having blood glucose-lowering effects, inhibitors of sodium glucose cotransporter 2 (SGLT2) afford renoprotection in diabetes. We sought to investigate which components of the glomerular filtration barrier could be involved in the antiproteinuric and renoprotective effects of SGLT2 inhibition in diabetes. BTBR ob/ob mice that develop a type 2 diabetic nephropathy received a standard diet with or without empagliflozin for 10 weeks, starting at 8 weeks of age, when animals had developed albuminuria. Empagliflozin caused marked decreases in blood glucose levels and albuminuria but did not correct glomerular hyperfiltration. The protective effect of empagliflozin against albuminuria was not due to a reduction in podocyte damage since empagliflozin did not affect the larger podocyte filtration slit pore size nor the defective expression of nephrin and nestin. Empagliflozin did not reduce the thickening of the GBM. In BTBR ob/ob mice, the most profound abnormality seen using electron microscopy was in the endothelial aspect of the glomerular capillary, with significant loss of endothelial fenestrations. Remarkably, empagliflozin ameliorated the subverted microvascular endothelial ultrastructure. Caveolae and bridging diaphragms between adjacent endothelial fenestrae were seen in diabetic mice and associated with increased expression of caveolin-1 and the appearance of PV-1. These endothelial abnormalities were limited by the SGLT2 inhibitor. While no expression of SGLT2 was found in glomerular endothelial cells, SGLT2 was expressed in the podocytes of diabetic mice. VEGF-A which is a known stimulus for endothelial caveolin-1 and PV-1 was increased in podocytes of BTBR ob/ob mice and normalized by SGLT2 inhibitor treatment. Thus, empagliflozin's protective effect on the glomerular endothelium of diabetic mice could be due to a limitation of the paracrine signaling of podocyte-derived VEGF-A that resulted in a reduction of the abnormal endothelial caveolin-1 and PV-1, with the consequent preservation of glomerular endothelial function and permeability. This article is protected by copyright. All rights reserved.

Hyperuricemia and the Risk of Heart Failure: Pathophysiology and Therapeutic Implications

The association between hyperuricemia and cardiovascular disease (CVD) has been reported and studied in the past two decades. Xanthine oxidase (XO) induced uric acid (UA) serves as a risk factor and has the independent prognostic and functional impact of heart failure (HF), but whether it plays a positive role in the pathogenesis of HF has remained unclear. Growing evidence suggest the up-regulated XO avtivity and increased production of free oxygen radical (ROS) correspondingly are the core pathogenesis of HF with hyperuricemia, which results in a whole cluster of pathophysiologic cardiovascular effects such as oxidative stress, endothelial dysfunction, vascular inflammation, left ventricular (LV) dysfunction as well as insulin resistance (IR). The use of XO inhibition represents a promising therapeutic choice in patients with HF due to its dual effect of lowering serum UA levels as well as reducing ROS production. This review will discuss the pathophysiologic mechanisms of hyperuricemia with HF, the targeted therapeutic interventions of UA lowering therapies (ULT) with XO inhibition and mechanism underlying beneficial effects of ULT. In addition, the review also summarizes current evidence on the role of ULT in HF and compares CV risk between allopurinol and febuxostat for practical and clinical purposes. Guidelines and implementation of CV risk management in daily practice will be discussed as well.

MAFLD vs. NAFLD: shared features and potential changes in epidemiology, pathophysiology, diagnosis, and pharmacotherapy

ABSTRACT

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide, placing an increasing burden on human health. NAFLD is a complex multifactorial disease involving genetic, metabolic, and environmental factors. It is closely associated with metabolic syndrome, obesity, and type 2 diabetes, of which insulin resistance is the main pathophysiological mechanism. Over the past few decades, investigation of the pathogenesis, diagnosis, and treatments has revealed different aspects of NAFLD, challenging the accuracy of definition and therapeutic strategy for the clinical practice. Recently, experts reach a consensus that NAFLD does not reflect the current knowledge, and metabolic (dysfunction) associated fatty liver disease (MAFLD) is suggested as a more appropriate term. The new definition puts increased emphasis on the important role of metabolic dysfunction in it. Herein, the shared features and potential changes in epidemiology, pathophysiology, diagnosis, and pharmacotherapy of the newly defined MAFLD, as compared with the formerly defined NAFLD, are reviewed for updating our understanding.