Evaluation of renal and cardiovascular protection mechanisms of SGLT2 inhibitors: model-based analysis of clinical data

Sodium-Glucose Cotransporter 2 Inhibitors in Diabetic Kidney Disease and beyond

Background

Sodium-glucose cotransporter 2 inhibitors (SGLT2is) have significantly impacted the management of diabetic kidney disease (DKD) and heart failure (HF), providing benefits beyond glycemic control. This review examines the mechanisms through which SGLT2is provide renal and cardiovascular protection and assesses their clinical efficacy.

Summary

By inducing glucosuria and natriuresis, SGLT2is alleviate multiple complications induced by chronic hyperglycemia. Moreover, SGLT2is reduce albuminuria, improve tubular function, and modulate erythropoiesis. Additionally, they mitigate inflammation and fibrosis by decreasing oxidative stress and downregulating proinflammatory pathways. Clinical trials have demonstrated significant reductions in renal and cardiovascular events among patients with type 2 diabetes mellitus. A comprehensive review of the literature was conducted through PubMed, highlighting the effects of SGLT2is and the results of major clinical trials involving SGLT2is.

Key Messages

SGLT2is play a crucial role in the management of DKD and HF by addressing multiple pathogenic pathways. Currently, SGLT2is are included in clinical guidelines for DKD and HF management, and their benefits extend to nondiabetic populations. Further research is needed to explore SGLT2is' multifaceted mechanisms and potential applications across diverse patient populations and different disease etiologies.

Sodium glucose transporter 2 inhibitors: Will these drugs benefit non-diabetic veterinary patients with cardiac and kidney diseases?

Sodium glucose transporter type 2 (SGLT2) inhibitors have been introduced into human medicine where their beneficial effects go beyond the expected improvement in blood glucose control. These drugs appear to prevent progression of both cardiovascular and kidney diseases, not only in diabetic but also in non-diabetic human patients. As these drugs have received conditional approval for use in diabetic cats and are being used in other veterinary species, the intriguing question as to whether they will have similar cardioprotective and nephroprotective effects in dogs and cats is being asked. The primary mechanism(s) by which SGLT2 inhibitors are cardio- and nephroprotective remain to be fully characterized. This paper reviews these suggested mechanisms in the context of the pathophysiology of progressive cardiovascular and kidney diseases in dogs and cats with the goal of predicting which categories of non-diabetic veterinary patients these drugs might be of most benefit.

Hemodynamic Effects of SGLT2 Inhibitors in Patients with and Without Diabetes Mellitus-A Narrative Review

Background: The current review aims to present the beneficial effects of SGLT2 inhibitors (dapagliflozin and empagliflozin) on several hemodynamic parameters such as blood pressure, filtration pressure at the level of the glomerular capillaries, and the improvement of the preload and afterload of heart muscle. In order to stop chronic kidney disease (CKD) from progressing, SGLT2 inhibitors have become an important disease-modifying treatment. Materials and methods: Recent clinical studies have shown the success of these drugs in treating heart failure, reducing the risk of cardiovascular events, hospitalization, and mortality. Results: The hemodynamic effects of SGLT2 inhibitors include a diuretic effect, due to reduced sodium reabsorption. Also, at this level, numerous studies have confirmed the beneficial effect of dapagliflozin in patients with chronic kidney disease, associated with a 44% reduced risk of progression in this pathology. SGLT2 inhibitors are associated with a reduction in blood pressure and weight loss, because of their diuretic effect, especially empagliflozin, which can explain the beneficial effects in patients with heart failure. In addition, mainly empagliflozin reduces stiffness and arterial resistance. Conclusions: Although the exact mechanism of action is unknown, SGLT2 inhibitors reduce the interstitial volume by blocking the tubular reabsorption of glucose. This leads to reduced blood pressure and enhanced endothelial function. Consequently, there have been improvements in hospitalization and fatality rates. Because of their beneficial effects, these medications have been guidelines for managing heart failure and chronic kidney disease.

Embracing sex-specific differences in engineered kidney models for enhanced biological understanding of kidney function

In vitro models serve as indispensable tools for advancing our understanding of biological processes, elucidating disease mechanisms, and establishing screening platforms for drug discovery. Kidneys play an instrumental role in the transport and elimination of drugs and toxins. Nevertheless, despite the well-documented inter-individual variability in kidney function and the multifaceted nature of renal diseases-spanning from their origin, trigger and which segment of the kidney is affected-to presentation, progression and prognosis, few studies take into consideration the variable of sex. Notably, the inherent disparities between female and male biology warrants a more comprehensive representation within in vitro models of the kidney. The omission of sex as a fundamental biological variable carries the substantial risk of overlooking sex-specific mechanisms implicated in health and disease, along with potential differences in drug responsiveness and toxicity profiles between sexes. This review emphasizes the importance of incorporating cellular, biological and functional sex-specific features of renal activity in health and disease in in vitro models. For that, we thoroughly document renal sex-specific features and propose a strategic experimental framework to integrate sex-based differences into human kidney in vitro models by outlining critical design criteria to elucidate sex-based features at cellular and tissue levels. The goal is to enhance the accuracy of models to unravel renal mechanisms, and improve our understanding of their impact on drug efficacy and safety profiles, paving the way for a more comprehensive understanding of patient-specific treatment modalities.

The role of venous capacity in fluid retention with endothelin A antagonism: Mathematical modelling of the RADAR trial

BACKGROUND AND PURPOSE

Endothelin-1 (ET-1) receptor A (ETA) antagonists reduce proteinuria and prevent renal outcomes in chronic kidney disease (CKD) patients, but their utility has been limited because of associated fluid retention, resulting in increased heart failure risk. Understanding the mechanisms responsible for fluid retention could result in solutions that preserve renoprotective effects while mitigating fluid retention, but the complexity of the endothelin system has made identification of the underlying mechanisms challenging.

APPROACH

We utilized a previously developed mathematical model of ET-1 kinetics, ETA receptor antagonism, kidney function, haemodynamics, and sodium and water homeostasis to evaluate hypotheses for mechanisms of fluid retention with ETA antagonism. To do this, we simulated the RADAR clinical trial of atrasentan in patients with type 2 diabetes and CKD and evaluated the ability of the model to predict the observed decreases in haematocrit, urine albumin creatinine ratio (UACR), mean arterial pressure (MAP), and estimated glomerular filtration rate (eGFR).

BACKGROUND AND KEY RESULTS

An effect of ETA antagonism on venodilation and increased venous capacitance was found to be the critical mechanism necessary to reproduce the simultaneous decrease in both MAP and haematocrit observed in RADAR.

CONCLUSIONS AND IMPACT

These findings indicate that fluid retention with ETA antagonism may not be caused by a direct antidiuretic effect within the kidney but is instead be an adaptive response to venodilation and increased venous capacity, which acutely tends to reduce cardiac filling pressure and cardiac output, and that fluid retention occurs in an attempt to maintain cardiac filling and cardiac output.

Mechanisms of heart failure and chronic kidney disease protection by SGLT2 inhibitors in nondiabetic conditions

Sodium-glucose cotransporter 2 inhibitors (SGLT2is), initially developed for type 2 diabetes (T2D) treatment, have demonstrated significant cardiovascular and renal benefits in heart failure (HF) and chronic kidney disease (CKD), irrespective of T2D. This review provides an analysis of the multifaceted mechanisms underlying the cardiorenal benefits of SGLT2i in HF and CKD outside of the T2D context. Eight major aspects of the protective effects of SGLT2i beyond glycemic control are explored: 1) the impact on renal hemodynamics and tubuloglomerular feedback; 2) the natriuretic effects via proximal tubule Na+/H+ exchanger NHE3 inhibition; 3) the modulation of neurohumoral pathways with evidence of attenuated sympathetic activity; 4) the impact on erythropoiesis, not only in the context of local hypoxia but also systemic inflammation and iron regulation; 5) the uricosuria and mitigation of the hyperuricemic environment in cardiorenal syndromes; 6) the multiorgan metabolic reprogramming including the potential induction of a fasting-like state, improvement in glucose and insulin tolerance, and stimulation of lipolysis and ketogenesis; 7) the vascular endothelial growth factor A (VEGF-A) upregulation and angiogenesis, and 8) the direct cardiac effects. The intricate interplay between renal, neurohumoral, metabolic, and cardiac effects underscores the complexity of SGLT2i actions and provides valuable insights into their therapeutic implications for HF and CKD. Furthermore, this review sets the stage for future research to evaluate the individual contributions of these mechanisms in diverse clinical settings.

Renal upregulation of NCC counteracts empagliflozin-mediated NHE3 inhibition in normotensive but not in hypertensive male rat

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) reduce blood pressure (BP) in patients with hypertension, yet the precise molecular mechanisms remain elusive. SGLT2i inhibits proximal tubule (PT) NHE3-mediated sodium reabsorption in normotensive rodents, yet no hypotensive effect is observed under this scenario. This study examined the effect of empagliflozin (EMPA) on renal tubular sodium transport in normotensive and spontaneously hypertensive rats (SHRs). It also tested the hypothesis that EMPA-mediated PT NHE3 inhibition in normotensive rats is associated with upregulation of distal nephron apical sodium transporters. EMPA administration for 14 days reduced BP in 12-wk-old SHRs but not in age-matched Wistar rats. PT NHE3 activity was inhibited by EMPA treatment in both Wistar and SHRs. In Wistar rats, EMPA increased NCC activity, mRNA expression, protein abundance, and phosphorylation levels, but not in SHRs. SHRs showed higher NKCC2 activity and an abundance of cleaved ENaC α and γ subunits compared with Wistar rats, none of which were affected by EMPA. Another set of male Wistar rats was treated with EMPA, the NCC inhibitor hydrochlorothiazide (HCTZ), and EMPA combined with HCTZ or vehicle for 14 days. In these rats, BP reduction was observed only with combined EMPA and HCTZ treatment, not with either drug alone. These findings suggest that NCC upregulation counteracts EMPA-mediated inhibition of PT NHE3 in male normotensive rats, maintaining their baseline BP. Moreover, the reduction of NHE3 activity without further upregulation of major apical sodium transporters beyond the PT may contribute to the BP-lowering effect of SGLT2i in experimental models and patients with hypertension.NEW & NOTEWORTHY This study suggests that reduced NHE3-mediated sodium reabsorption in the renal proximal tubule may account, at least in part, for the BP-lowering effect of SGLT2 inhibitors in the setting of hypertension. It also demonstrates that chronic treatment with SGLT2 inhibitors upregulates NCC activity, phosphorylation, and expression in the distal tubule of normotensive but not hypertensive rats. SGLT2 inhibitor-mediated upregulation of NCC seems crucial to counteract proximal tubule natriuresis in subjects with normal BP.

SGLT2 inhibitors: from glucose-lowering to cardiovascular benefits

An increasing number of individuals are at high risk of type 2 diabetes (T2D) and its cardiovascular complications, including heart failure (HF), chronic kidney disease (CKD), and eventually premature death. The sodium-glucose co-transporter-2 (SGLT2) protein sits in the proximal tubule of human nephrons to regulate glucose reabsorption and its inhibition by gliflozins represents the cornerstone of contemporary T2D and HF management. Herein, we aim to provide an updated overview of the pleiotropy of gliflozins, provide mechanistic insights and delineate related cardiovascular (CV) benefits. By discussing contemporary evidence obtained in preclinical models and landmark randomized controlled trials, we move from bench to bedside across the broad spectrum of cardio- and cerebrovascular diseases. With landmark randomized controlled trials confirming a reduction in major adverse CV events (MACE; composite endpoint of CV death, non-fatal myocardial infarction, and non-fatal stroke), SGLT2 inhibitors strongly mitigate the risk for heart failure hospitalization in diabetics and non-diabetics alike while conferring renoprotection in specific patient populations. Along four major pathophysiological axes (i.e. at systemic, vascular, cardiac, and renal levels), we provide insights into the key mechanisms that may underlie their beneficial effects, including gliflozins' role in the modulation of inflammation, oxidative stress, cellular energy metabolism, and housekeeping mechanisms. We also discuss how this drug class controls hyperglycaemia, ketogenesis, natriuresis, and hyperuricaemia, collectively contributing to their pleiotropic effects. Finally, evolving data in the setting of cerebrovascular diseases and arrhythmias are presented and potential implications for future research and clinical practice are comprehensively reviewed.

Quantifying the integrated physiological effects of endothelin-1 on cardiovascular and renal function in healthy subjects: a mathematical modeling analysis

Endothelin-1 (ET-1) is a potent vasoconstrictor with strong anti-natriuretic and anti-diuretic effects. While many experimental studies have elucidated the mechanisms of ET-1 through its two receptors, ETA and ETB, the complexity of responses and sometimes conflicting data make it challenging to understand the effects of ET-1, as well as potential therapeutic antagonism of ET-1 receptors, on human physiology. In this study, we aimed to develop an integrated and quantitative description of ET-1 effects on cardiovascular and renal function in healthy humans by coupling existing experimental data with a mathematical model of ET-1 kinetics and an existing mathematical model of cardiorenal function. Using a novel agnostic and iterative approach to incorporating and testing potential mechanisms, we identified a minimal set of physiological actions of endothelin-1 through ETA and ETB receptors by fitting the physiological responses (changes in blood pressure, renal blood flow, glomerular filtration rate (GFR), and sodium/water excretion) to ET-1 infusion, with and without ETA/ETB antagonism. The identified mechanisms align with previous experimental studies on ET-1 and offer novel insights into the relative magnitude and significance of endothelin's effects. This model serves as a foundation for further investigating the mechanisms of ET-1 and its antagonists.

An In Silico Platform to Predict Cardiotoxicity Risk of Anti-tumor Drug Combination with hiPSC-CMs Based In Vitro Study

OBJECTIVE

Antineoplastic agent-induced systolic dysfunction is a major reason for interruption of anticancer treatment. Although targeted anticancer agents infrequently cause systolic dysfunction, their combinations with chemotherapies remarkably increase the incidence. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) provide a potent in vitro model to assess cardiovascular safety. However, quantitatively predicting the reduction of ejection fraction based on hiPSC-CMs is challenging due to the absence of the body's regulatory response to cardiomyocyte injury.

METHODS

Here, we developed and validated an in vitro-in vivo translational platform to assess the reduction of ejection fraction induced by antineoplastic drugs based on hiPSC-CMs. The translational platform integrates drug exposure, drug-cardiomyocyte interaction, and systemic response. The drug-cardiomyocyte interaction was implemented as a mechanism-based toxicodynamic (TD) model, which was then integrated into a quantitative system pharmacology-physiological-based pharmacokinetics (QSP-PBPK) model to form a complete translational platform. The platform was validated by comparing the model-predicted and clinically observed incidence of doxorubicin and trastuzumab-induced systolic dysfunction.

RESULTS

A total of 33,418 virtual patients were incorporated to receive doxorubicin and trastuzumab alone or in combination. For doxorubicin, the QSP-PBPK-TD model successfully captured the overall trend of systolic dysfunction incidences against the cumulative doses. For trastuzumab, the predicted incidence interval was 0.31-2.7% for single-agent treatment and 0.15-10% for trastuzumab-doxorubicin sequential treatment, covering the observations in clinical reports (0.50-1.0% and 1.5-8.3%, respectively).

CONCLUSIONS

In conclusion, the in vitro-in vivo translational platform is capable of predicting systolic dysfunction incidence almost merely depend on hiPSC-CMs, which could facilitate optimizing the treatment protocol of antineoplastic agents.

Dapagliflozin ameliorates diabetes-induced spermatogenic dysfunction by modulating the adenosine metabolism along the gut microbiota-testis axis

Male infertility is one of the most common complications of diabetes mellitus (DM). Dapagliflozin is widely used to manage the type II DM. This study aimed to assess the dapagliflozin's effects on the spermatogenesis by administering either dapagliflozin (Dapa) or vehicle (db) to male db/db mice, and using littermate male db/m mice as the control (Con). We further performed the integrative analyses of the cecal shotgun metagenomics, cecal/plasmatic/testicular metabolomics, and testicular proteomics. We found that dapagliflozin treatment significantly alleviated the diabetes-induced spermatogenic dysfunction by improving sperm quality, including the sperm concentration and sperm motility. The overall microbial composition was reshaped in Dapa mice and 13 species (such as Lachnospiraceae bacterium 3-1) were regarded as potential beneficial bacteria. Metabolites exhibited modified profiles, in which adenosine, cAMP, and 2'-deoxyinosine being notably altered in the cecum, plasma, and testis, respectively. Testicular protein expression patterns were similar between the Dapa and Con mice. In vivo results indicated that when compared with db group, dapagliflozin treatment alleviated apoptosis and oxidative stress in testis tissues by down-regulating 2'-deoxyinosine. This was further validated by in vitro experiments using GC-2 cells. Our findings support the potential use of dapagliflozin to prevent the diabetes-induced impaired sperm quality and to treat diabetic male infertility.

Potential Underlying Mechanisms Explaining the Cardiorenal Benefits of Sodium-Glucose Cotransporter 2 Inhibitors

There is a bidirectional pathophysiological interaction between the heart and the kidneys, and prolonged physiological stress to the heart and/or the kidneys can cause adverse cardiorenal complications, including but not limited to subclinical cardiomyopathy, heart failure and chronic kidney disease. Whilst more common in individuals with Type 2 diabetes, cardiorenal complications also occur in the absence of diabetes. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) were initially approved to reduce hyperglycaemia in patients with Type 2 diabetes. Recently, these agents have been shown to significantly improve cardiovascular and renal outcomes in patients with and without Type 2 diabetes, demonstrating a robust reduction in hospitalisation for heart failure and reduced risk of progression of chronic kidney disease, thus gaining approval for use in treatment of heart failure and chronic kidney disease. Numerous potential mechanisms have been proposed to explain the cardiorenal effects of SGLT2i. This review provides a simplified summary of key potential cardiac and renal mechanisms underlying the cardiorenal benefits of SGT2i and explains these mechanisms in the clinical context. Key mechanisms related to the clinical effects of SGLT2i on the heart and kidneys explained in this publication include their impact on (1) tissue oxygen delivery, hypoxia and resultant ischaemic injury, (2) vascular health and function, (3) substrate utilisation and metabolic health and (4) cardiac remodelling. Knowing the mechanisms responsible for SGLT2i-imparted cardiorenal benefits in the clinical outcomes will help healthcare practitioners to identify more patients that can benefit from the use of SGLT2i.

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.

The role of glycosaminoglycans in blood pressure regulation

Essential hypertension (HT) is the global health problem and is a major risk factor for the development of cardiovascular and kidney disease. High salt intake has been associated with HT and impaired kidney sodium excretion is considered to be a major mechanism for the development of HT. Although kidney has a very important role in regulation of BP, this traditional view of BP regulation was challenged by recent findings suggesting that nonosmotic tissue sodium deposition is very important for BP regulation. This new paradigm indicates that sodium can be stored and deposited nonosmotically in the interstitium without water retention and without increased BP. One of the major determinants of this deposition is glycosaminoglycans (GAGs). By binding to GAGs found in the endothelial surface layer (ESL) which contains glycocalyx, sodium is osmotically inactivated and not induce concurrent water retention. Thus, GAGs has important function for homeostatic BP and sodium regulation. In the current review, we summarized the role of GAGs in ESL and BP regulation.

Sodium-glucose cotransporter-2 inhibitors in heart failure: Potential decongestive mechanisms and current clinical studies

Congestion is a key pathophysiological feature of heart failure (HF) syndrome that drives most of the clinical manifestations of acute HF and is related with poor quality of life and outcomes. Therefore, safe and effective decongestion is an important therapeutic target in the management of acute HF and despite the use of guideline-recommended loop diuretics, adequate decongestion is not always achieved in patients with acute HF. Recently, sodium-glucose cotransporter-2 (SGLT-2) inhibitors have been shown to provide clinical benefits across a broad spectrum of patients with HF, including consistent reduction in the risk of acute HF episodes. While the exact mechanisms underlying these benefits remain a matter of debate, a growing body of evidence suggests that effective decongestion may be partly responsible, especially in the setting of acute HF. In this review, we discuss the potential decongestive mechanisms of SGLT-2 inhibitors, such as osmotic diuresis, natriuresis, preservation of glomerular filtration and facilitation of interstitial drainage, which can collectively translate into effective and safe decongestion. Furthermore, we provide a comprehensive review of up-to-date clinical data of SGLT-2 inhibitor use in the acute HF population.

Critical Analysis of the Effects of SGLT2 Inhibitors on Renal Tubular Sodium, Water and Chloride Homeostasis and Their Role in Influencing Heart Failure Outcomes

SGLT2 (sodium-glucose cotransporter 2) inhibitors interfere with the reabsorption of glucose and sodium in the early proximal renal tubule, but the magnitude and duration of any ensuing natriuretic or diuretic effect are the result of an interplay between the degree of upregulation of SGLT2 and sodium-hydrogen exchanger 3, the extent to which downstream compensatory tubular mechanisms are activated, and (potentially) the volume set point in individual patients. A comprehensive review and synthesis of available studies reveals several renal response patterns with substantial variation across studies and clinical settings. However, the common observation is an absence of a large acute or chronic diuresis or natriuresis with these agents, either when given alone or combined with other diuretics. This limited response results from the fact that renal compensation to these drugs is rapid and nearly complete within a few days or weeks, preventing progressive volume losses. Nevertheless, the finding that fractional excretion of glucose and lithium (the latter being a marker of proximal sodium reabsorption) persists during long-term treatment with SGLT2 inhibitors indicates that pharmacological tolerance to the effects of these drugs at the level of the proximal tubule does not meaningfully occur. This persistent proximal tubular effect of SGLT2 inhibitors can be hypothesized to produce a durable improvement in the internal set point for volume homeostasis, which may become clinically important during times of fluid expansion. However, it is difficult to know whether a treatment-related change in the volume set point actually occurs or contributes to the effect of these drugs to reduce the risk of major heart failure events. SGLT2 inhibitors exert cardioprotective effects by a direct effect on cardiomyocytes that is independent of the presence of or binding to SGLT2 or the actions of these drugs on the proximal renal tubule. Nevertheless, changes in the volume set point mediated by SGLT2 inhibitors might potentially act cooperatively with the direct favorable molecular and cellular effects of these drugs on cardiomyocytes to mediate their benefits on the development and clinical course of heart failure.

Understanding the Mechanisms and Treatment of Heart Failure: Quantitative Systems Pharmacology Models with a Focus on SGLT2 Inhibitors and Sex-Specific Differences

Heart failure (HF), which is a major clinical and public health challenge, commonly develops when the myocardial muscle is unable to pump an adequate amount of blood at typical cardiac pressures to fulfill the body's metabolic needs, and compensatory mechanisms are compromised or fail to adjust. Treatments consist of targeting the maladaptive response of the neurohormonal system, thereby decreasing symptoms by relieving congestion. Sodium-glucose co-transporter 2 (SGLT2) inhibitors, which are a recent antihyperglycemic drug, have been found to significantly improve HF complications and mortality. They act through many pleiotropic effects, and show better improvements compared to others existing pharmacological therapies. Mathematical modeling is a tool used to describe the pathophysiological processes of the disease, quantify clinically relevant outcomes in response to therapies, and provide a predictive framework to improve therapeutic scheduling and strategies. In this review, we describe the pathophysiology of HF, its treatment, and how an integrated mathematical model of the cardiorenal system was built to capture body fluid and solute homeostasis. We also provide insights into sex-specific differences between males and females, thereby encouraging the development of more effective sex-based therapies in the case of heart failure.

SGLT2 inhibitors in the treatment of type 2 cardiorenal syndrome: Focus on renal tubules

The pathogenesis of type 2 cardiorenal syndrome (CRS) is mostly associated with reduced cardiac output, increased central venous pressure (CVP), activation of the renin-angiotensin-aldosterone system (RAAS), inflammation, and oxidative stress. As a drug to treat diabetes, sodium-glucose transporter 2 inhibitor (SGLT2i) has been gradually found to have a protective effect on the heart and kidney and has a certain therapeutic effect on CRS. In the process of chronic heart failure (CHF) leading to chronic renal insufficiency, the renal tubular system, as the main functional part of the kidney, is the first to be damaged, but this damage can be reversed. In this review, we focus on the protective mechanisms of SGLT2i targeting renal tubular in the treatment of CRS, including natriuresis and diuresis to relieve renal congestion, attenuate renal tubular fibrosis, improve energy metabolism of renal tubular, and slow tubular inflammation and oxidative stress. This may have beneficial effects on the treatment of CRS and is a direction for future research.

Innovations in medical therapy of heart failure with reduced ejection fraction

Heart failure with reduced ejection fraction (HFrEF) is a pathological condition still characterized by high rates of mortality and disease exacerbation frequently leading to hospitalization, thus there is a continuous need for pharmacological treatments impacting on disease stability and long-term prognosis. Moreover, the phenotype of heart failure patients is continuously changing over time, and the development of new heart failure drugs is crucial to promote a personalized and targeted approach. In recent years, several therapeutic innovations have emerged in the landscape of acute and chronic HFrEF, largely changing and improving our approach to the disease. Various studies on new drugs and experimental therapeutic approaches are ongoing. The present review discusses the latest data on both recently approved drugs and developing therapeutic targets, in order to provide a critical overview for an informed and optimal approach to such a complex disease.

A review of cardiovascular benefits of SGLT2 inhibitors

Sodium-glucose cotransporter 2 inhibitor (SGLT2I) is a new type of hypoglycemic drug that targets the kidney. As research continues to advance on this topic, it has been found that SGLT2I has multiple protective effects, such as hypoglycemic, cardio-renal protective, antihypertensive, and lipid-lowering effects. This review discusses the current concepts and possible mechanisms of SGLT2I in the treatment of heart failure, myocardial infarction, hypertension, cardiomyopathy and arrhythmia to provide a reference for clinicians to use drugs more reasonably and scientifically.

Cardiovascular outcomes trials: a paradigm shift in the current management of type 2 diabetes

Cardiovascular disease (CVD) is the leading cause of mortality and morbidity in patients with type 2 diabetes (T2D). Historical concerns about cardiovascular (CV) risks associated with certain glucose-lowering medications gave rise to the introduction of cardiovascular outcomes trials (CVOTs). Initially implemented to help monitor the CV safety of glucose-lowering drugs in patients with T2D, who either had established CVD or were at high risk of CVD, data that emerged from some of these trials started to show benefits. Alongside the anticipated CV safety of many of these agents, evidence for certain sodium-glucose transporter 2 (SGLT2) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have revealed potential cardioprotective effects in patients with T2D who are at high risk of CVD events. Reductions in 3-point major adverse CV events (3P-MACE) and CV death have been noted in some of these CVOTs, with additional benefits including reduced risks of hospitalisation for heart failure, progression of renal disease, and all-cause mortality. These new data are leading to a paradigm shift in the current management of T2D, with international guidelines now prioritising SGLT2 inhibitors and/or GLP-1 RAs in certain patient populations. However, clinicians are faced with a large volume of CVOT data when seeking to use this evidence base to bring opportunities to improve CV, heart failure and renal outcomes, and even reduce mortality, in their patients with T2D. The aim of this review is to provide an in-depth summary of CVOT data-crystallising the key findings, from safety to efficacy-and to offer a practical perspective for physicians. Finally, we discuss the next steps for the post-CVOT era, with ongoing studies that may further transform clinical practice and improve outcomes for people with T2D, heart failure or renal disease.

Determining risk factors for triple whammy acute kidney injury

Concurrent use of a diuretic, a renin-angiotensin system (RAS) inhibitor, and a non-steroidal anti-inflammatory drug (NSAID) significantly increases the risk of acute kidney injury (AKI). This phenomenon is known as "triple whammy". Diuretics and RAS inhibitors, such as an angiotensin converting enzyme (ACE) inhibitor or angiotensin receptor blocker, are often prescribed in tandem for the treatment of hypertension, whereas some NSAIDs, such as ibuprofen, are available over the counter. As such, concurrent treatment with all three drugs is common. The goals of this study are to better understand the mechanisms underlying the development of triple whammy AKI and to identify physiological factors that may increase an individual's susceptibility. To accomplish these goals, we utilize sex-specific computational models of long-term blood pressure regulation. These models include variables describing the heart and circulation, kidney function, sodium and water reabsorption in the nephron and the RAS and are parameterized separately for men and women. Hypertension is modeled as overactive renal sympathetic nervous activity. Model simulations suggest that low water intake, the myogenic response, and drug sensitivity may predispose patients with hypertension to develop triple whammy-induced AKI. Triple treatment involving an ACE inhibitor, furosemide, and NSAID results in blood pressure levels similar to double treatment with ACEI and furosemide. Additionally, the male and female hypertensive models act similarly in most situations, except for the ACE inhibitor and NSAID double treatment.

Extending the ambit of SGLT2 inhibitors beyond diabetes: a review of clinical and preclinical studies on non-diabetic kidney disease

BACKGROUND

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are novel antidiabetic agents with overwhelming cardiorenal protection. Recent trials focusing on the nephroprotective role of SGLT2i have underscored its success as a phenomenal agent in halting the progression of kidney disease in patients with and without Type 2 diabetes mellitus. Multitudes of pleiotropic effects on tubules have raised hopes for reasonable nephroprotection beyond the purview of the hyperglycemic milieu.

AREA COVERED

This review summarizes various animal and human data as evidence for the utility of SGLT2i in non-diabetic chronic kidney disease (CKD). Web-based medical database entries were searched. On the premise of existing evidence, we have discussed mechanisms likely contributing to nephroprotection by SGLT2i in patients with non-diabetic CKD.

EXPERT OPINION

Further elucidation of mechanisms of nephroprotection offered by SGLT2i is required to extend its use as a nephroprotective agent. The use of non-traditional markers of kidney damage in future studies would improve the evaluation of their role in attenuating CKD progression. Emerging animal data support the early use of SGLT2i in states of modest proteinuria for superior outcomes. Future long-term trials in patients should aim to address the time of intervention with SGLT2i during the natural disease course of CKD for best outcomes.

Sodium Glucose Transporter, Type 2 (SGLT2) Inhibitors (SGLT2i) and Glucagon-Like Peptide 1-Receptor Agonists: Newer Therapies in Whole-Body Glucose Stabilization

Diabetes is a worldwide epidemic that is increasing rapidly to become the seventh leading cause of death in the world. The increased incidence of this disease mirrors a similar uptick in obesity and metabolic syndrome, and, collectively, these conditions can cause deleterious effects on a number of organ systems including the renal and cardiovascular systems. Historically, treatment of type 2 diabetes has focused on decreasing hyperglycemia and glycated hemoglobin levels. However, it now is appreciated that there is more to the puzzle. Emerging evidence has indicated that newer classes of diabetes drugs, sodium-glucose co-transporter 2 inhibitors and glucagon-like peptide 1-receptor agonists, improve cardiovascular and renal function, while appropriately managing hyperglycemia. In this review, we highlight the recent clinical and preclinical studies that have shed light on sodium-glucose co-transporter 2 inhibitors and glucagon-like peptide 1-receptor agonists and their ability to stabilize blood glucose levels while offering whole-body protection in diabetic and nondiabetic patient populations.

Predicted Cardiac Functional Responses to Renal Actions of SGLT2i in the DAPACARD Trial Population: A Mathematical Modeling Analysis

Sodium-glucose cotransporter-2 inhibitors (SGLT2is) have been shown to reduce the risk of worsening heart failure (HF) in subjects with HF and a reduced ejection fraction (HFrEF) in multiple clinical trials. The DAPACARD clinical trial was conducted to examine the effects of DAPAgliflozin on CARDiac substrate uptake, myocardial efficiency, and myocardial contractile work in type 2 diabetes mellitus (T2DM) subjects. As a complement to the clinical study, a mechanistic mathematical model of cardiorenal physiology was used to quantify the influence of established natriuretic/diuretic effects of SGLT2i on cardiac function (myocardial efficiency and global longitudinal strain). Virtual participants reflecting the participant-level characteristics in the DAPACARD trial were produced by varying model parameters over physiologically plausible ranges. A second virtual population was generated by inducing a state of HFrEF in the DAPACARD T2DM virtual participants (DAPACARD-HFrEF virtual participants) for comparison. Cardiac responses to placebo and SGLT2i were simulated over 42 days. Cardiac hemodynamic improvements were predicted in DAPACARD-HFrEF virtual participants but not in DAPACARD virtual participants. In particular, the natriuresis/diuresis induced by SGLT2i improved the global longitudinal strain and myocardial efficiency in DAPACARD-HFrEF virtual participants within the first 14 days (change from baseline: global longitudinal strain: -0.95% and myocardial efficiency: 0.34%), whereas the global longitudinal strain and myocardial efficiency in DAPACARD virtual participants were slightly worse (change from baseline: global longitudinal strain: 0.35% and myocardial efficiency: -0.01%). The results of the DAPACARD virtual participants modeling were in line with the clinical data but do not preclude additional effects from other mechanisms of SGLT2i. This article is protected by copyright. All rights reserved.

Sodium-glucose cotransporter 2 inhibitor effects on heart failure hospitalization and cardiac function: systematic review

AIMS

To systematically review randomized controlled trials assessing effects of sodium-glucose cotransporter 2 inhibitors (SGLT2is) on hospitalization for heart failure (HHF) and cardiac structure/function and explore randomized controlled trial (RCT)-derived evidence for SGLT2i efficacy mechanisms in heart failure (HF).

METHODS AND RESULTS

Systematic searches of Medline and Embase were performed. In seven trials [3730-17 160 patients; low risk of bias (RoB)], SGLT2is significantly reduced the relative risk of HHF by 27-39% vs. placebo, including in two studies in patients with HF with reduced ejection fraction with or without type-2 diabetes mellitus (T2DM). Improvements in conventional cardiovascular risk factors, including glycaemic levels, cannot account for these effects. Five trials (56-105 patients; low RoB) assessed the effects of 6-12 months of SGLT2i treatment on left ventricular structure/function; four reported significant improvements vs. placebo, and one did not. Five trials (low RoB) assessed SGLT2i treatment effects on serum N-terminal pro B-type natriuretic peptide levels; significant reductions vs. placebo were reported after 8-12 months (two studies; 3730-4744 patients) but not ≤12 weeks (three studies; 80-263 patients). Limited available RCT-derived evidence suggests various possible cardioprotective SGLT2i mechanisms, including improved haemodynamics (natriuresis and reduced interstitial fluid without blood volume contraction/neurohormonal activation) and vascular function, enhanced erythropoiesis, reduced tissue sodium and epicardial fat/inflammation, decreased sympathetic tone, and beneficial changes in cellular energetics.

CONCLUSIONS

Sodium-glucose cotransporter 2 inhibitors reduce HHF regardless of T2DM status, and reversal of adverse left ventricular remodelling likely contributes to this efficacy. Hypothesis-driven mechanistic trials remain sparse, although numerous trials are planned or ongoing.

CKD subpopulations defined by risk-factors: A longitudinal analysis of electronic health records

Chronic kidney disease (CKD) is a progressive disease that evades early detection and is associated with various comorbidities. Although clinical comprehension and control of these comorbidities is crucial for CKD management, complex pathophysiological interactions and feedback loops make this a formidable task. We have developed a hybrid semimechanistic modeling methodology to investigate CKD progression. The model is represented as a system of ordinary differential equations with embedded neural networks and takes into account complex disease progression pathways, feedback loops, and effects of 53 medications to generate time trajectories of eight clinical biomarkers that capture CKD progression due to various risk factors. The model was applied to real world data of US patients with CKD to map the available longitudinal information onto a set of time‐invariant patient‐specific parameters with a clear biological interpretation. These parameters describing individual patients were used to segment the cohort using a clustering approach. Model‐based simulations were conducted to investigate cluster‐specific treatment strategies. The model was able to reliably reproduce the variability in biomarkers across the cohort. The clustering procedure segmented the cohort into five subpopulations – four with enhanced sensitivity to a specific risk factor (hypertension, hyperlipidemia, hyperglycemia, or impaired kidney) and one that is largely insensitive to any of the risk factors. Simulation studies were used to identify patient‐specific strategies to restrain or prevent CKD progression through management of specific risk factors. The semimechanistic model enables identification of disease progression phenotypes using longitudinal data that aid in prioritizing treatment strategies at individual patient level.

The Na/K-ATPase Signaling and SGLT2 Inhibitor-Mediated Cardiorenal Protection: A Crossed Road?

In different large-scale clinic outcome trials, sodium (Na⁺)/glucose co-transporter 2 (SGLT2) inhibitors showed profound cardiac- and renal-protective effects, making them revolutionary treatments for heart failure and kidney disease. Different theories are proposed according to the emerging protective effects other than the original purpose of glucose-lowering in diabetic patients. As the ATP-dependent primary ion transporter providing the Na⁺ gradient to drive other Na⁺-dependent transporters, the possible role of the sodium–potassium adenosine triphosphatase (Na/K-ATPase) as the primary ion transporter and its signaling function is not explored.

The Potential Roles of Osmotic and Nonosmotic Sodium Handling in Mediating the Effects of Sodium-Glucose Cotransporter 2 Inhibitors on Heart Failure

Concomitant type 2 diabetes and chronic kidney disease increases the risk of heart failure. Recent studies demonstrate beneficial effects of sodium-glucose cotransporter 2 (SGLT2) inhibitors on chronic kidney disease progression and heart failure hospitalization in patients with and without diabetes. In addition to inhibiting glucose reabsorption, SGLT2 inhibitors decrease proximal tubular sodium reabsorption, possibly leading to transient natriuresis. We review the hypothesis that SGLT2 inhibitor’s natriuretic and osmotic diuretic effects mediate their cardioprotective effects. The degree to which these benefits are related to changes in sodium, independent of the kidney, is currently unknown. Aside from effects on osmotically active sodium, we explore the intriguing possibility that SGLT2 inhibitors could also modulate nonosmotic sodium storage. This alternative hypothesis is based on emerging literature that challenges the traditional 2-compartment model of sodium balance to provide support for a 3-compartment model that includes the binding of sodium to glycosaminoglycans, such as those in muscles and skin. This recent research on nonosmotic sodium storage, as well as direct cardiac effects of SGLT2 inhibitors, provides possibilities for other ways in which SGLT2 inhibitors might mitigate heart failure risk. Overall, we review the effects of SGLT2 inhibitors on sodium balance and sensitivity, cardiac tissue, interstitial fluid and plasma volume, and nonosmotic sodium storage.

SGLT2 inhibitors have cardiovascular benefits that include HF outcomes in patients with and without diabetes. Because the underlying mechanisms are only partly explained by improvements in BP, body weight, or glucose control, other mechanisms have been proposed. We focus here on a central role for effects on sodium as underlying the positive benefits of SGLT2 inhibitors in HF. We explore the new (although still unconfirmed) idea that SGLT2 inhibitors exert some of their positive effects by affecting nonosmotic sodium (ie, sodium bound to muscles and skin and not dissolved in the blood).

SGLT2 inhibitors have emerged as a class of drugs, previously prescribed for patients with T2D, that have in more recent years been shown to have substantial heart and kidney clinical benefits in patients with and without T2D.

The degree to which these benefits are related to kidney-independent changes in sodium homeostasis is currently unknown.

A better understanding of the nonosmotic mechanisms underpinning the benefits of SGLT2 inhibition on HF (with reduced or preserved left ventricular ejection fraction) may allow researchers to assess the effects of SGLT2 inhibitors in combination with other treatments that affect sodium balance.

Exploring new treatment options for polycystic ovary syndrome: Review of a novel antidiabetic agent SGLT2 inhibitor

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women of reproductive age associated with long-term metabolic and cardiovascular consequences. A plethora of symptoms and their severity differentiate on an individual level, giving the syndrome numerous phenotypes. Due to menstrual cycle abnormalities, women suffer from irregular menstrual bleeding, difficulty in conception, and infertility. Furthermore, the risk of pregnancy complications such as gestational diabetes mellitus, hypertensive disorders of pregnancy, and preterm birth are higher in women with PCOS than in the general population. Often, women with PCOS have comorbidities such as dyslipidemia, obesity, glucose intolerance or diabetes type 2, non-alcoholic fatty liver disease, and metabolic syndrome, which all influence the treatment plan. Historic insulin-sensitizing agents, although good for some of the metabolic derangements, do not offer long-term cardiovascular benefits; therefore, new treatment options are of paramount importance. Sodium-glucose co-transporter-2 (SGLT-2) inhibitors, a new class of antidiabetic agents with beneficial cardiovascular, bodyweight, and antihyperglycemic effects, although not approved for the treatment of PCOS, might be an attractive therapeutic addition in the PCOS armamentarium. Namely, recent studies with SGLT-2 inhibitors showed promising improvements in anthropometric parameters and body composition in patients with PCOS. It is important to further explore the SGLT-2 inhibitors potential as an early therapeutic option because of the PCOS-related risk of metabolic, reproductive, and psychological consequences.

Empagliflozin Inhibits Proximal Tubule NHE3 Activity, Preserves GFR, and Restores Euvolemia in Nondiabetic Rats with Induced Heart Failure

BACKGROUND

SGLT2 inhibitors reduce the risk of heart failure (HF) mortality and morbidity, regardless of the presence or absence of diabetes, but the mechanisms underlying this benefit remain unclear. Experiments with nondiabetic HF rats tested the hypothesis that the SGLT2 inhibitor empagliflozin (EMPA) inhibits proximal tubule (PT) NHE3 activity and improves renal salt and water handling.

METHODS

Male Wistar rats were subjected to myocardial infarction or sham operation. After 4 weeks, rats that developed HF and sham rats were treated with EMPA or untreated for an additional 4 weeks. Immunoblotting and quantitative RT-PCR evaluated SGLT2 and NHE3 expression. Stationary in vivo microperfusion measured PT NHE3 activity.

RESULTS

EMPA-treated HF rats displayed lower serum B-type natriuretic peptide levels and lower right ventricle and lung weight to tibia length than untreated HF rats. Upon saline challenge, the diuretic and natriuretic responses of EMPA-treated HF rats were similar to those of sham rats and were higher than those of untreated HF rats. Additionally, EMPA treatment prevented GFR decline and renal atrophy in HF rats. PT NHE3 activity was higher in HF rats than in sham rats, whereas treatment with EMPA markedly reduced NHE3 activity. Unexpectedly, SGLT2 protein and mRNA abundance were upregulated in the PT of HF rats.

CONCLUSIONS

Prevention of HF progression by EMPA is associated with reduced PT NHE3 activity, restoration of euvolemia, and preservation of renal mass. Moreover, dysregulation of PT SGLT2 may be involved in the pathophysiology of nondiabetic HF.

Cardiorenal Systems Modeling: Left Ventricular Hypertrophy and Differential Effects of Antihypertensive Therapies on Hypertrophy Regression

Cardiac and renal function are inextricably connected through both hemodynamic and neurohormonal mechanisms, and the interaction between these organ systems plays an important role in adaptive and pathophysiologic remodeling of the heart, as well as in the response to renally acting therapies. Insufficient understanding of the integrative function or dysfunction of these physiological systems has led to many examples of unexpected or incompletely understood clinical trial results. Mathematical models of heart and kidney physiology have long been used to better understand the function of these organs, but an integrated model of renal function and cardiac function and cardiac remodeling has not yet been published. Here we describe an integrated cardiorenal model that couples existing cardiac and renal models, and expands them to simulate cardiac remodeling in response to pressure and volume overload, as well as hypertrophy regression in response to angiotensin receptor blockers and beta-blockers. The model is able to reproduce different patterns of hypertrophy in response to pressure and volume overload. We show that increases in myocyte diameter are adaptive in pressure overload not only because it normalizes wall shear stress, as others have shown before, but also because it limits excess volume accumulation and further elevation of cardiac stresses by maintaining cardiac output and renal sodium and water balance. The model also reproduces the clinically observed larger LV mass reduction with angiotensin receptor blockers than with beta blockers. We further provide a mechanistic explanation for this difference by showing that heart rate lowering with beta blockers limits the reduction in peak systolic wall stress (a key signal for myocyte hypertrophy) relative to ARBs.

Systems Modeling to Quantify Safety Risks in Early Drug Development: Using Bifurcation Analysis and Agent-Based Modeling as Examples

Quantitative Systems Toxicology (QST) models, recapitulating pharmacokinetics and mechanism of action together with the organic response at multiple levels of biological organization, can provide predictions on the magnitude of injury and recovery dynamics to support study design and decision-making during drug development. Here, we highlight the application of QST models to predict toxicities of cancer treatments, such as cytopenia(s) and gastrointestinal adverse effects, where narrow therapeutic indexes need to be actively managed. The importance of bifurcation analysis is demonstrated in QST models of hematologic toxicity to understand how different regions of the parameter space generate different behaviors following cancer treatment, which results in asymptotically stable predictions, yet highly irregular for specific schedules, or oscillating predictions of blood cell levels. In addition, an agent-based model of the intestinal crypt was used to simulate how the spatial location of the injury within the crypt affects the villus disruption severity. We discuss the value of QST modeling approaches to support drug development and how they align with technological advances impacting trial design including patient selection, dose/regimen selection, and ultimately patient safety.

Predicted Cardiac Hemodynamic Consequences of the Renal Actions of SGLT2i in the DAPA-HF Study Population: A Mathematical Modeling Analysis

The Dapagliflozin and Prevention of Adverse Outcomes in Heart Failure (DAPA-HF) study demonstrated that dapagliflozin, a sodium-glucose cotransporter-2 inhibitor (SGLT2i), reduced heart failure hospitalization and cardiovascular death in patients with heart failure with reduced ejection fraction (HF-rEF), with and without type 2 diabetes mellitus. Multiple potential mechanisms have been proposed to explain this benefit, which may be multifactorial. This study aimed to quantify the contribution of the known natriuretic/diuretic effects of SGLT2is to changes in cardiac hemodynamics, remodeling, and fluid homeostasis in the setting of HF-rEF. An integrated cardiorenal mathematical model was used to simulate inhibition of SGLT2 and its consequences on cardiac hemodynamics in a virtual population of HF-rEF patients generated by varying model parameters over physiologically plausible ranges and matching to baseline characteristics of individual DAPA-HF trial patients. Cardiovascular responses to placebo and SGLT2i over time were then simulated. The baseline characteristics of the HF-rEF virtual population and DAPA-HF were in good agreement. SGLT2i-induced diuresis and natriuresis that reduced blood volume and interstitial fluid volume, relative to placebo within 14 days. This resulted in decreased left ventricular end-diastolic volume and pressure, indicating reduced cardiac preload. Thereafter, blood volume and interstitial fluid volume again began to accumulate, but pressures and volumes remained shifted lower relative to placebo. After 1 year, left ventricle mass was lower and ejection fraction was higher than placebo. These simulations considered only hemodynamic consequences of the natriuretic/diuretic effects of SGLT2i, as other mechanisms may contribute additional benefits besides those predictions.

[The agreed experts' position of the Eurasian Association of Therapists on tactics of management of patients with comorbid pathology infected with SARS-Cov-2]

The agreement of experts of the Eurasian Association of Therapists (EAT) discusses pathogenesis and treatment of COVID-19. Modern data on the characteristics of cardiovascular, kidney, respiratory damage in SARS-infected CoV-2 are presented. The tactics of managing patients initially having cardiovascular diseases, diabetes mellitus, chronic obstructive pulmonary disease, bronchial asthma, chronic kidney disease are discussed in detail. The article presents data on drug interaction of drugs.

Renal Effects of Dapagliflozin in People with and without Diabetes with Moderate or Severe Renal Dysfunction: Prospective Modeling of an Ongoing Clinical Trial

Sodium glucose cotransporter 2 inhibitors (SGLT2i) reduce cardiovascular events and onset and progression of renal disease by mechanisms that remain incompletely understood but may include clearance of interstitial congestion and reduced glomerular hydrostatic pressure. The ongoing DAPASALT mechanistic clinical study will evaluate natriuretic, diuretic, plasma/extracellular volume, and blood pressure responses to dapagliflozin in people with type 2 diabetes with normal or impaired renal function (D-PRF and D-IRF, respectively) and in normoglycemic individuals with renal impairment (N-IRF). In this study, a mathematical model of renal physiology, pathophysiology, and pharmacology was used to prospectively predict changes in sodium excretion, blood and interstitial fluid volume (IFV), blood pressure, glomerular filtration rate, and albuminuria in DAPASALT. After validating the model with previous diabetic nephropathy trials, virtual patients were matched to DAPASALT inclusion/exclusion criteria, and the DAPASALT protocol was simulated. Predicted changes in glycosuria, blood pressure, glomerular filtration rate, and albuminuria were consistent with other recent studies in similar populations. Predicted albuminuria reductions were 46% in D-PRF, 34.8% in D-IRF, and 14.2% in N-IRF. The model predicts a similarly large IFV reduction between D-PRF and D-IRF and less, but still substantial, IFV reduction in N-IRF, even though glycosuria is attenuated in groups with impaired renal function. When DAPASALT results become available, comparison with these simulations will provide a basis for evaluating how well we understand the cardiorenal mechanism(s) of SGLT2i. Meanwhile, these simulations link dapagliflozin's renal mechanisms to changes in IFV and renal biomarkers, suggesting that these benefits may extend to those with impaired renal function and individuals without diabetes. SIGNIFICANCE STATEMENT: Mechanisms of SGLT2 inhibitors' cardiorenal benefits remain incompletely understood. We used a mathematical model of renal physiology/pharmacology to prospectively predict responses to dapagliflozin in the ongoing DAPASALT study. Key predictions include similarly large interstitial fluid volume (IFV) reductions between subjects with normal and impaired renal function and less, but still substantial, IFV reduction in those without diabetes, even though glycosuria is attenuated in these groups. Comparing prospective simulations and study results will assess how well we understand the cardiorenal mechanism(s) of SGLT2 inhibitors.

Cardiorenal Protection With the Newer Antidiabetic Agents in Patients With Diabetes and Chronic Kidney Disease: A Scientific Statement From the American Heart Association

Chronic kidney disease (CKD) with type 2 diabetes (T2D) is a major public health problem, resulting in significant cardiovascular and kidney adverse outcomes worldwide. Despite the widespread use of standard-of-care therapies for CKD with T2D over the past few decades, rates of progression to end-stage kidney disease remain high with no beneficial impact on its accompanying burden of cardiovascular disease. The advent of the newer classes of antihyperglycemic agents, including SGLT2 (sodium glucose cotransporter 2) inhibitors and GLP-1 (glucagon-like peptide-1) receptor agonists, has changed the landscape of therapeutic options for patients with CKD with T2D, with demonstration of significant reductions in cardiovascular adverse events and progression to end-stage kidney disease. Several potential mechanisms exist through which these beneficial effects are achieved in both drug classes, which may be independent of their antihyperglycemic effects. This scientific statement summarizes the current literature on the cardiorenal protective effects with SGLT2 inhibitors and GLP-1 receptor agonists in patients with CKD and T2D. It reviews potential mechanistic pathways that may drive these benefits and summarizes the literature on adverse effects in patients with CKD and T2D at risk for or with established cardiovascular disease. Last, it provides practical guidance on a proposed collaborative care model bridging cardiologists, nephrologists, endocrinologists, and primary care physicians to facilitate the prompt and appropriate integration of these therapeutic classes in the management of patients with T2D and CKD.

Role of sodium-glucose cotransporter 2 inhibition to mitigate diabetic kidney disease risk in type 1 diabetes

Diabetic kidney disease (DKD) is a common complication of type 1 diabetes (T1D) and a major risk factor for premature death from cardiovascular disease (CVD). Current treatments, such as control of hyperglycaemia and hypertension, are beneficial, but only partially protect against DKD. Finding new, safe and effective therapies to halt nephropathy progression has proven to be challenging. Sodium-glucose cotransporter 2 (SGLT2) inhibitors have demonstrated, in addition to glycaemic lowering, impressive protection against DKD and CVD progression in people with type 2 diabetes. Although these beneficial cardiorenal effects may also apply to people with T1D, supporting data are lacking. Furthermore, the increased rates of euglycaemic diabetic ketoacidosis may limit the use of this class in people with T1D. In this review we highlight the pathophysiology of DKD in T1D and the unmet need that exists. We further detail the beneficial and adverse effects of SGLT2 inhibitors based on their mechanism of action. Finally, we balance the effects in people with T1D and indicate future lines of research.

Cardiac and renal function interactions in heart failure with reduced ejection fraction: A mathematical modeling analysis

Congestive heart failure is characterized by suppressed cardiac output and arterial filling pressure, leading to renal retention of salt and water, contributing to further volume overload. Mathematical modeling provides a means to investigate the integrated function and dysfunction of heart and kidney in heart failure. This study updates our previously reported integrated model of cardiac and renal functions to account for the fluid exchange between the blood and interstitium across the capillary membrane, allowing the simulation of edema. A state of heart failure with reduced ejection fraction (HF-rEF) was then produced by altering cardiac parameters reflecting cardiac injury and cardiovascular disease, including heart contractility, myocyte hypertrophy, arterial stiffness, and systemic resistance. After matching baseline characteristics of the SOLVD clinical study, parameters governing rates of cardiac remodeling were calibrated to describe the progression of cardiac hemodynamic variables observed over one year in the placebo arm of the SOLVD clinical study. The model was then validated by reproducing improvements in cardiac function in the enalapril arm of SOLVD. The model was then applied to prospectively predict the response to the sodium-glucose co-transporter 2 (SGLT2) inhibitor dapagliflozin, which has been shown to reduce heart failure events in HF-rEF patients in the recent DAPAHF clinical trial by incompletely understood mechanisms. The simulations predict that dapagliflozin slows cardiac remodeling by reducing preload on the heart, and relieves congestion by clearing interstitial fluid without excessively reducing blood volume. This provides a quantitative mechanistic explanation for the observed benefits of SGLT2i in HF-rEF. The model also provides a tool for further investigation of heart failure drug therapies.

Noncardiac comorbidity clustering in heart failure: an overlooked aspect with potential therapeutic door

Heart failure is associated with a range of comorbidities that have the potential to impair both quality of life and clinical outcome. Unfortunately, noncardiac diseases are underrepresented in large randomized clinical trials, and their management remains poorly understood. In clinical practice, the prevalence of comorbidities in heart failure is high. Although the prognostic impact of comorbidities is well known, their prevalence and impact in specific heart failure settings have been overlooked. Many studies have described specific single noncardiac conditions, but few have examined their overall burden and grading in patients with multiple comorbidities. The risk of comorbidities in patients with heart failure rises with more advanced disease, older age, and increased frailty-three conditions that are poorly represented in clinical trials. The pathogenic links between comorbidities and heart failure involve many pathways and include neurohormonal overdrive, inflammatory activation, oxidative stress, and endothelial dysfunction. Such interactions may worsen prognoses, but details of these relationships are still under investigation. We propose a shift from cardiac-focused care to a more systemic approach that considers all noncardiac diseases and related medications. Some new drugs class such as ARNI or SGLT2 inhibitors could change prognosis by acting directly or indirectly on metabolic disorders and related vascular consequences.

Mathematical models for kidney function focusing on clinical interest

We give an overview of mathematical models of renal physiology and anatomy with the clinician in mind. Beyond the past focus on issues of local transport mechanisms along the nephron and the urine concentrating mechanism, recent models have brought insight into difficult problems such as renal ischemia (oxygen and CO₂ diffusion in the medulla) or calcium and potassium homeostasis. They have also provided revealing 3D reconstructions of the full trajectories of families of nephrons and collecting ducts through cortex and medulla. The recent appearance of sophisticated whole-kidney models representing nephrons and their associated renal vasculature promises more realistic simulation of renal pathologies and pharmacological treatments in the foreseeable future.

Cardioprotection conferred by sodium-glucose cotransporter 2 inhibitors: a renal proximal tubule perspective

Sodium-glucose cotransporter 2 (SGLT2) inhibitors, also known as gliflozins, improve glycemia by suppressing glucose reuptake in the renal proximal tubule. Currently, SGLT2 inhibitors are primarily indicated as antidiabetic agents; however, their benefits extend far beyond glucose control. Cardiovascular outcome trials indicated that all studied SGLT2 inhibitors remarkably and consistently reduce cardiovascular mortality and hospitalization for heart failure (HF) in type 2 diabetes (T2D) patients. Nevertheless, the mechanisms underlying the unprecedented cardiovascular benefits of gliflozins remain elusive. Multiple processes that directly or indirectly improve myocardial performance may be involved, including the amelioration of proximal tubular dysfunction. Therefore, this paper provides a perspective on the potential cellular and molecular mechanisms of the proximal tubule that may, at least in part, mediate the cardioprotection conferred by SGLT2 inhibitors. Specifically, we focus on the effects of SGLT2 on extracellular volume homeostasis, including its plausible functional and physical association with the apical Na⁺/H⁺ exchanger isoform 3 as well as its complex and its possible bidirectional interactions with the intrarenal angiotensin system and renal sympathetic nervous system. We also discuss evidence supporting a potential benefit of gliflozins in reducing cardiovascular risk, attributable to their effect on proximal tubule handling of uric acid and albumin as well as in erythropoietin production. Unraveling the mechanisms behind the beneficial actions of SGLT2 inhibitors may not only contribute to a better understanding of the pathophysiology of cardiovascular diseases but also enable repurposing of gliflozins to improve the routine management of HF patients with or without T2D.

Effect of type 2 diabetes medications on fracture risk

Type 2 diabetes, one of the most frequent chronic diseases, has an important effect on bone metabolism, with most studies reporting an increased prevalence of fractures in these patients despite an apparently increased bone mineral density. Most probable explanation is an alteration of bone structure/quality with increased fragility but the different diabetes medications influence the risk of fracture. While metformin and incretin-based therapies are safe, thiazolidinediones and canagliflozin (sodium-glucose cotransporter-2 inhibitor) negatively impact bone metabolism and should be avoided in subjects at increased risk of fractures. Insulin and sulphonylureas are generally safe but can increase the risk of hypoglycemia and falls with subsequent traumatic fractures. Their combination should be avoided, especially in elderly subjects.

Evaluation of the effects of sodium-glucose co-transporter 2 inhibition with empagliflozin on morbidity and mortality in patients with chronic heart failure and a preserved ejection fraction: rationale for and design of the EMPEROR-Preserved Trial

BACKGROUND

The principal biological processes that characterize heart failure with a preserved ejection fraction (HFpEF) are systemic inflammation, epicardial adipose tissue accumulation, coronary microcirculatory rarefaction, myocardial fibrosis and vascular stiffness; the resulting impairment of left ventricular and aortic distensibility (especially when accompanied by impaired glomerular function and sodium retention) causes increases in cardiac filling pressures and exertional dyspnoea despite the relative preservation of left ventricular ejection fraction. Independently of their actions on blood glucose, sodium-glucose co-transporter 2 (SGLT2) inhibitors exert a broad range of biological effects (including actions to inhibit cardiac inflammation and fibrosis, antagonize sodium retention and improve glomerular function) that can ameliorate the pathophysiological derangements in HFpEF. Such SGLT2 inhibitors exert favourable effects in experimental models of HFpEF and have been found in large-scale trials to reduce the risk for serious heart failure events in patients with type 2 diabetes, many of whom were retrospectively identified as having HFpEF.

STUDY DESIGN

The EMPEROR-Preserved Trial is enrolling ≈5750 patients with HFpEF (ejection fraction >40%), with and without type 2 diabetes, who are randomized to receive placebo or empagliflozin 10 mg/day, which is added to all appropriate treatments for HFpEF and co-morbidities.

STUDY AIMS

The primary endpoint is the time-to-first-event analysis of the combined risk for cardiovascular death or hospitalization for heart failure. The trial will also evaluate the effects of empagliflozin on renal function, cardiovascular death, all-cause mortality and recurrent hospitalization events, and will assess a wide range of biomarkers that reflect important pathophysiological mechanisms that may drive the evolution of HFpEF. The EMPEROR-Preserved Trial is well positioned to determine if empagliflozin can have a meaningful impact on the course of HFpEF, a disorder for which there are currently few therapeutic options.

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.

Quantitative Systems Pharmacology: An Exemplar Model-Building Workflow With Applications in Cardiovascular, Metabolic, and Oncology Drug Development

Quantitative systems pharmacology (QSP), a mechanistically oriented form of drug and disease modeling, seeks to address a diverse set of problems in the discovery and development of therapies. These problems bring a considerable amount of variability and uncertainty inherent in the nonclinical and clinical data. Likewise, the available modeling techniques and related software tools are manifold. Appropriately, the development, qualification, application, and impact of QSP models have been similarly varied. In this review, we describe the progressive maturation of a QSP modeling workflow: a necessary step for the efficient, reproducible development and qualification of QSP models, which themselves are highly iterative and evolutive. Furthermore, we describe three applications of QSP to impact drug development; one supporting new indications for an approved antidiabetic clinical asset through mechanistic hypothesis generation, one highlighting efficacy and safety differentiation within the sodium‐glucose cotransporter‐2 inhibitor drug class, and one enabling rational selection of immuno‐oncology drug combinations.