Mineralocorticoid Receptor Blockers: Novel Selective Nonsteroidal Mineralocorticoid Receptor Antagonists

The renin-angiotensin-aldosterone system: An old tree sprouts new shoots

The intricate physiological and pathological diversity of the Renin-Angiotensin-Aldosterone System (RAAS) underpins its role in maintaining bodily equilibrium. This paper delves into the classical axis (Renin-ACE-Ang II-AT1R axis), the protective arm (ACE2-Ang (1-7)-MasR axis), the prorenin-PRR-MAP kinases ERK1/2 axis, and the Ang IV-AT4R-IRAP cascade of RAAS, examining their functions in both physiological and pathological states. The dysregulation or hyperactivation of RAAS is intricately linked to numerous diseases, including cardiovascular disease (CVD), renal damage, metabolic disease, eye disease, Gastrointestinal disease, nervous system and reproductive system diseases. This paper explores the pathological mechanisms of RAAS in detail, highlighting its significant role in disease progression. Currently, in addition to traditional drugs like ACEI, ARB, and MRA, several novel therapeutics have emerged, such as angiotensin receptor-enkephalinase inhibitors, nonsteroidal mineralocorticoid receptor antagonists, aldosterone synthase inhibitors, aminopeptidase A inhibitors, and angiotensinogen inhibitors. These have shown potential efficacy and application prospects in various clinical trials for related diseases. Through an in-depth analysis of RAAS, this paper aims to provide crucial insights into its complex physiological and pathological mechanisms and offer valuable guidance for developing new therapeutic approaches. This comprehensive discussion is expected to advance the RAAS research field and provide innovative ideas and directions for future clinical treatment strategies.

Aldosterone Synthase Inhibitors for Cardiorenal Protection: Ready for Prime Time?

BACKGROUND

Aldosterone is the principal mineralocorticoid hormone and the final effector of the renin-angiotensin-aldosterone system. This hormone is primarily synthesized by the CYP11B2 enzyme and produced by the adrenal zona glomerulosa. Through genomic and non-genomic effects, it plays an important role in cardiovascular and renal disease. To counteract aldosterone-mediated damage, steroidal mineralocorticoid receptor antagonists are recommended by international guidelines, but endocrine side effects often limit their use in a substantial proportion of patients. Conversely, nonsteroidal mineralocorticoid receptor antagonists, with an improved selectivity and safety profile, are gaining a prominent position among therapeutic pillars. However, blocking the mineralocorticoid receptors does not completely inhibit aldosterone effects because of escape mechanisms and non-genomic activity. Thus, inhibiting aldosterone synthesis could be a promising strategy to prevent aldosterone-mediated cardiorenal damage. The limited specificity for CYP11B2 and side effects due to off-target activity hampered the development of first-generation aldosterone synthase inhibitors (ASIs).

SUMMARY

The development of highly specific ASIs led to successful clinical trials in patients with resistant and uncontrolled hypertension. Additionally, a recent randomized clinical trial showed a significant benefit of ASIs in patients with chronic kidney disease and albuminuria.

KEY MESSAGES

The strength of the clinical evidence collected so far is still limited, and larger outcome-based clinical trials are needed to confirm the promising role of ASIs in cardiorenal damage.

Analysis of eplerenone in the FDA adverse event reporting system (FAERS) database: a focus on overall patient population and gender-specific subgroups

Introduction: Eplerenone is approved for the treatment of hypertension as well as symptomatic heart failure with reduced ejection fraction (HFrEF) following an acute myocardial infarction. However, the adverse events (AEs) have not been systematically analyzed. The aim of this study was to identify adverse drug reactions (ADRs) related to eplerenone using the FDA Adverse Event Reporting System (FAERS) database. By identifying previously unreported AEs, the study could potentially contribute to updating the drug's label. Methods: In order to find significant AEs, four algorithms, including Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPNN) and Empirical Bayesian Geometric Mean (EBGM), were used to analyze the signal strength of the ADRs connected to eplerenone that were gathered from the FAERS database over the previous 20 years. Results: From 2004Q1 to 2023Q4, a total of 20, 629, 811 reported cases were gathered from the FAERS database for this study. After processing the data and filtering, 1,874 case reports were analyzed. Of these cases, 1,070 AEs were identified, 128 of which were eplerenone-related ADRs. We investigated the occurrence of ADRs induced by eplerenone in 27 organ systems. Our study showed that the AEs listed in the medication's package insert correspond with those listed in the literature, including hyperkalemia and increased creatinine. Additionally, the prescription label for eplerenone does not include all system organ class (SOC) terms, like Vascular disorders, hepatobiliary Disorders, etc. Discussion: The study used multiple algorithms to quantify the signal strength and then identified any previously unrecognized ADRs, further studies are needed to confirm the association of ADRs with eplerenone. The findings of this study may provide important insights into the safety profile of eplerenone, ensure that healthcare providers have up-to-date information about their potential risks and help guide them in the correct use of the drug.

Strategies to address diabetic kidney disease burden in Mexico: a narrative review by the Mexican College of Nephrologists

Chronic kidney disease (CKD) is a growing global public health challenge worldwide. In Mexico, CKD prevalence is alarmingly high and remains a leading cause of morbidity and mortality. Diabetic kidney disease (DKD), a severe complication of diabetes, is a leading determinant of CKD. The escalating diabetes prevalence and the complex regional landscape in Mexico underscore the pressing need for tailored strategies to reduce the burden of CKD. This narrative review, endorsed by the Mexican College of Nephrologists, aims to provide a brief overview and specific strategies for healthcare providers regarding preventing, screening, and treating CKD in patients living with diabetes in all care settings. The key topics covered in this review include the main cardiometabolic contributors of DKD (overweight/obesity, hyperglycemia, arterial hypertension, and dyslipidemia), the identification of kidney-related damage markers, and the benefit of novel pharmacological approaches based on Sodium-Glucose Co-Transporter-2 Inhibitors (SGLT2i) and Glucagon-Like Peptide-1 Receptor Agonists (GLP-1 RA). We also address the potential use of novel therapies based on Mineralocorticoid Receptor Antagonists (MRAs) and their future implications. Emphasizing the importance of multidisciplinary treatment, this narrative review aims to promote strategies that may be useful to alleviate the burden of DKD and its associated complications. It underscores the critical role of healthcare providers and advocates for collaborative efforts to enhance the quality of life for millions of patients affected by DKD.

Efficacy and Safety of Esaxerenone in Hypertensive Patients with Left Ventricular Hypertrophy (ESES-LVH) Study: A Multicenter, Open-Label, Prospective, Interventional Study

INTRODUCTION

In contrast to the antihypertensive effect of esaxerenone, there is little evidence of its cardioprotective effect. We investigated the efficacy and safety of esaxerenone in patients with uncontrolled hypertension and left ventricular hypertrophy taking a renin-angiotensin system inhibitor (RASi) or calcium-channel blocker (CCB).

METHODS

This was a multicenter, open-label, exploratory study with a 24-week treatment period. Esaxerenone was orally administered at an initial dose of 2.5 mg/day (maximum dose: 5 mg/day). The primary endpoints were the change in morning home systolic blood pressure (BP)/diastolic BP and change and percentage change in left ventricular mass index (LVMI) from baseline to end of treatment (EOT). Key secondary endpoints included change from baseline in bedtime home and office BP, achievement rate of target BP, and safety.

RESULTS

In total, 60 patients were enrolled. Morning home systolic/diastolic BP was significantly decreased from baseline to EOT in the total population (- 11.5/ - 4.7 mmHg, p < 0.001) and in both the RASi and CCB subcohorts (all p < 0.01). Significant reductions in bedtime home and office BP were shown in the total population and both subcohorts. LVMI was also significantly decreased from baseline to EOT in the total population (- 9.9 g/m2, - 8.5%, both p < 0.001) and both subcohorts (all p < 0.05). The incidences of treatment-emergent adverse events (TEAEs) and drug-related TEAEs were 35.0% and 3.3%, respectively; most were mild or moderate. No new safety concerns were identified.

CONCLUSION

Esaxerenone showed favorable antihypertensive and cardioprotective effects and safety in hypertensive patients with cardiac hypertrophy.

TRIAL REGISTRATION

Japan Registry of Clinical Trials (jRCTs071190043).

Mineralocorticoid receptor antagonist use in chronic kidney disease with type 2 diabetes: a clinical practice document by the European Renal Best Practice (ERBP) board of the European Renal Association (ERA)

Chronic kidney disease (CKD) in individuals with type 2 diabetes (T2D) represents a major public health issue; it develops in about 30%-40% of patients with diabetes mellitus and is the most common cause of CKD worldwide. Patients with CKD and T2D are at high risk of both developing kidney failure and of cardiovascular events. Renin-angiotensin system (RAS) blockers were considered the cornerstone of treatment of albuminuric CKD in T2D for more than 20 years. However, the residual risk of progression to more advanced CKD stages under RAS blockade remains high, while in major studies with these agents in patients with CKD and T2D no significant reductions in cardiovascular events and mortality were evident. Steroidal mineralocorticoid receptor antagonists (MRAs) are known to reduce albuminuria in individuals on RAS monotherapy, but their wide clinical use has been curtailed by the significant risk of hyperkalemia and absence of trials with hard renal outcomes. In recent years, non-steroidal MRAs have received increasing interest due to their better pharmacologic profile. Finerenone, the first compound of this class, was shown to effectively reduce the progression of kidney disease and of cardiovascular outcomes in participants with T2D in phase 3 trials. This clinical practice document prepared from a task force of the European Renal Best Practice board summarizes current knowledge on the role of MRAs in the treatment of CKD in T2D aiming to support clinicians in decision-making and everyday management of patients with this condition.

Future treatments in hypertension: Can we meet the unmet needs of patients?

The prevalence of arterial hypertension is approximately 47% in the United States and 55% in Europe. Multiple different medical therapies are used to treat hypertension including diuretics, beta blockers, calcium channel blockers, angiotensin receptor blockers, angiotensin converting enzyme inhibitors, alpha blockers, central acting alpha receptor agonists, neprilysin inhibitors and vasodilators. However, despite the numerous number of medications, the prevalence of hypertension is on the rise, a considerable proportion of the hypertensive population is resistant to these therapeutic modalities and a definitive cure is not possible with the current treatment approaches. Therefore, there is a need for novel therapeutic strategies to provide better treatment and control of hypertension. In this review, our aim is to describe the latest developments in the treatment of hypertension including novel medication classes, gene therapies and RNA-based modalities.

Aldosterone: Renal Action and Physiological Effects

Aldosterone exerts profound effects on renal and cardiovascular physiology. In the kidney, aldosterone acts to preserve electrolyte and acid-base balance in response to changes in dietary sodium (Na+ ) or potassium (K+ ) intake. These physiological actions, principally through activation of mineralocorticoid receptors (MRs), have important effects particularly in patients with renal and cardiovascular disease as demonstrated by multiple clinical trials. Multiple factors, be they genetic, humoral, dietary, or otherwise, can play a role in influencing the rate of aldosterone synthesis and secretion from the adrenal cortex. Normally, aldosterone secretion and action respond to dietary Na+ intake. In the kidney, the distal nephron and collecting duct are the main targets of aldosterone and MR action, which stimulates Na+ absorption in part via the epithelial Na+ channel (ENaC), the principal channel responsible for the fine-tuning of Na+ balance. Our understanding of the regulatory factors that allow aldosterone, via multiple signaling pathways, to function properly clearly implicates this hormone as central to many pathophysiological effects that become dysfunctional in disease states. Numerous pathologies that affect blood pressure (BP), electrolyte balance, and overall cardiovascular health are due to abnormal secretion of aldosterone, mutations in MR, ENaC, or effectors and modulators of their action. Study of the mechanisms of these pathologies has allowed researchers and clinicians to create novel dietary and pharmacological targets to improve human health. This article covers the regulation of aldosterone synthesis and secretion, receptors, effector molecules, and signaling pathways that modulate its action in the kidney. We also consider the role of aldosterone in disease and the benefit of mineralocorticoid antagonists. © 2023 American Physiological Society. Compr Physiol 13:4409-4491, 2023.

Mineralocorticoid receptor antagonists for nephroprotection and cardioprotection in patients with diabetes mellitus and chronic kidney disease

Diabetic kidney disease (DKD) develops in ∼40% of patients with diabetes and is the most common cause of chronic kidney disease (CKD) worldwide. Patients with CKD, especially those with diabetes mellitus, are at high risk of both developing kidney failure and cardiovascular (CV) death. The use of renin-angiotensin system (RAS) blockers to reduce the incidence of kidney failure in patients with DKD dates back to studies that are now ≥20 years old. During the last few years, sodium-glucose co-transporter-2 inhibitors (SGLT2is) have shown beneficial renal effects in randomized trials. However, even in response to combined treatment with RAS blockers and SGLT2is, the renal residual risk remains high with kidney failure only deferred, but not avoided. The risk of CV death also remains high even with optimal current treatment. Steroidal mineralocorticoid receptor antagonists (MRAs) reduce albuminuria and surrogate markers of CV disease in patients already on optimal therapy. However, their use has been curtailed by the significant risk of hyperkalaemia. In the FInerenone in reducing kiDnEy faiLure and dIsease prOgression in DKD (FIDELIO-DKD) study comparing the actions of the non-steroidal MRA finerenone with placebo, finerenone reduced the progression of DKD and the incidence of CV events, with a relatively safe adverse event profile. This document presents in detail the available evidence on the cardioprotective and nephroprotective effects of MRAs, analyses the potential mechanisms involved and discusses their potential future place in the treatment of patients with diabetic CKD.

Evolution of Mineralocorticoid Receptor Antagonists in the Treatment of Chronic Kidney Disease Associated with Type 2 Diabetes Mellitus

Chronic kidney disease (CKD) is one of the most frequent complications associated with type 2 diabetes mellitus (T2DM) and is also an independent risk factor for cardiovascular disease. The mineralocorticoid receptor (MR) is a nuclear receptor expressed in many tissue types, including kidney and heart. Aberrant and long-term activation of MR by aldosterone in patients with T2DM triggers detrimental effects (eg, inflammation and fibrosis) in these tissues. The suppression of aldosterone at the early stage of T2DM has been a therapeutic strategy for patients with T2DM-associated CKD. Although patients have been treated with renin-angiotensin system (RAS) blockers for decades, RAS blockers alone are not sufficient to prevent CKD progression. Steroidal MR antagonists (MRAs) have been used in combination with RAS blockers; however, undesired adverse effects have restricted their usage, prompting the development of nonsteroidal MRAs with better target specificity and safety profiles. Recently conducted studies, Finerenone in Reducing Kidney Failure and Disease Progression in Diabetic Kidney Disease (FIDELIO-DKD) and Finerenone in Reducing Cardiovascular Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD), have reported that finerenone, a nonsteroidal MRA, improves both renal and cardiovascular outcomes compared with placebo. In this article, we review the history of MRA development and discuss the possibility of its combination with other treatment options, such as sodium-glucose cotransporter 2 inhibitors, glucagon-like peptide-1 receptor agonists, and potassium binders for patients with T2DM-associated CKD.

Aldosterone, Mineralocorticoid Receptor Activation, and CKD: A Review of Evolving Treatment Paradigms

Mineralocorticoid receptor (MR) activation is involved in propagating kidney injury, inflammation, and fibrosis and in the progression of chronic kidney disease (CKD). Multiple clinical studies have defined the efficacy of MR antagonism in attenuating progressive kidney disease, and the US Food and Drug Administration recently approved the nonsteroidal mineralocorticoid receptor antagonist (MRA) finerenone for this indication. In this review, we consider the basic science and clinical applicability of MR antagonism. Because hyperkalemia constitutes a constraint to implementing evidence-based MR blockade, we review MRA-associated hyperkalemia in the context of finerenone and discuss evolving mitigation strategies to enhance the safety and efficacy of this treatment. Although the FIDELIO-DKD and FIGARO-DKD clinical trials focused solely on patients with type 2 diabetes mellitus, we propose that MR activation and the resulting inflammation and fibrosis act as a substantive pathogenetic mediator not only in people with diabetic CKD but also in those with CKD without diabetes. We close by briefly discussing both recently initiated and future clinical trials that focus on extending the attributes of MR antagonism to a wider array of nondiabetic kidney disorders, such as patients with nonalbuminuric CKD.

Effects of Finerenone, a Novel Nonsteroidal Mineralocorticoid Receptor Antagonist, on Cardiovascular Disease, Chronic Kidney Disease, and Blood Pressure

PURPOSE OF REVIEW

Finerenone, an FDA-approved nonsteroidal mineralocorticoid receptor (MR) antagonist, has been evaluated in context of chronic kidney disease (CKD) and associated cardiovascular disease (CVD). In this review, we summarize pre-clinical and clinical studies focused on the impact of finerenone on these disease processes.

RECENT FINDINGS

Activation of the MR upregulates genes encoding for facilitators of tissue damage. Finerenone binding to a helix domain in this receptor inhibits receptor function. Studies in murine models of kidney disease, heart failure, hypertension, and vascular injury demonstrate significant protective effects of finerenone against further disease progression, as well as association with reduced oxidative stress, inflammation, and fibrosis. Phase 1-3 clinical trials with finerenone show safety and efficacy in improving renal and cardiovascular outcomes in patients with CKD. Research thus far encourages the addition of finerenone to the standard of care for certain CKD patients, especially those especially at risk for or with pre-existing cardiovascular disease. Continued study of the effect of finerenone in diverse patient populations and different disease states is needed.

Discovery of Apararenone (MT-3995) as a Highly Selective, Potent, and Novel Nonsteroidal Mineralocorticoid Receptor Antagonist

Overactivation of the mineralocorticoid receptor (MR) is involved in many diseases, such as hypertension, kidney disease, and heart failure. Thus, MR antagonists (MRAs) are expected to be beneficial to patients with these diseases. In order to identify novel nonsteroidal MRAs that overcome the issues of already marketed steroidal MRAs, we searched for new compounds guided by our hypothesis that T-shaped compounds with a hydrophobic core structure, two polar functional groups at both extremities able to interact with MR, and a bulky substituent that can interfere with the folding of the C-terminal helix 12 may exhibit antagonist activity toward MR. We discovered that the novel 1,4-benzoxazin-3-one derivative 19 (apararenone: MT-3995) acted as a highly selective and potent nonsteroidal MRA. Apararenone exhibited a more potent antihypertensive and organ-protective activity than steroidal MRA eplerenone in a primary aldosteronism rat model obtained by infusing aldosterone in uninephrectomized rats.

GRK5 is an essential co-repressor of the cardiac mineralocorticoid receptor and is selectively induced by finerenone

BACKGROUND

In the heart, aldosterone (Aldo) binds the mineralocorticoid receptor (MR) to exert damaging, adverse remodeling-promoting effects. We recently showed that G protein-coupled receptor-kinase (GRK)-5 blocks the cardiac MR by directly phosphorylating it, thereby repressing its transcriptional activity. MR antagonist (MRA) drugs block the cardiac MR reducing morbidity and mortality of advanced human heart failure. Non-steroidal MRAs, such as finerenone, may provide better cardio-protection against Aldo than classic, steroidal MRAs, like spironolactone and eplerenone.

AIM

To investigate potential differences between finerenone and eplerenone at engaging GRK5-dependent cardiac MR phosphorylation and subsequent blockade.

METHODS

We used H9c2 cardiomyocytes, which endogenously express the MR and GRK5.

RESULTS

GRK5 phosphorylates the MR in H9c2 cardiomyocytes in response to finerenone but not to eplerenone. Unlike eplerenone, finerenone alone potently and efficiently suppresses cardiac MR transcriptional activity, thus displaying inverse agonism. GRK5 is necessary for finerenone’s inverse agonism, since GRK5 genetic deletion renders finerenone incapable of blocking cardiac MR transcriptional activity. Eplerenone alone does not fully suppress cardiac MR basal activity regardless of GRK5 expression levels. Finally, GRK5 is necessary for the anti-apoptotic, anti-oxidative, and anti-fibrotic effects of both finerenone and eplerenone against Aldo, as well as for the higher efficacy and potency of finerenone at blocking Aldo-induced apoptosis, oxidative stress, and fibrosis.

CONCLUSION

Finerenone, but not eplerenone, induces GRK5-dependent cardiac MR inhibition, which underlies, at least in part, its higher potency and efficacy, compared to eplerenone, as an MRA in the heart. GRK5 acts as a co-repressor of the cardiac MR and is essential for efficient MR antagonism in the myocardium

Aldosterone Blockade in Acute Myocardial Infarction: A Systematic Review and Meta-Analysis

Background

A comprehensive evaluation of the benefits of mineralocorticoid receptor antagonists (MRA) in acute myocardial infarction (AMI) patients is lacking.

Objective

To summarize the evidence on the efficacy and safety of MRA in patients admitted for AMI.

Methods

Articles were identified through PubMed, Embase, Cochrane Library, Ovid (Medline1946-2021), and ClinicalTrials.gov databases from their inception to December 31, 2020.

Results

15 articles with a total of 11,861 patients were included. MRA reduced the risk of all-cause mortality by 16% (relative ratio (RR): 0.84; 95% confidence interval (CI) (0.76, 0.94); P = 0.002) and the incidence of cardiovascular adverse events by 12% (RR: 0.88, 95% CI (0.83, 0.93), P < 0.00001) in post-AMI patients, and further analysis demonstrated that early administration of MRA within 7 days after AMI resulted in a greater reduction in all-cause mortality (RR: 0.72, 95% CI (0.61, 0.85), P < 0.0001). Subgroup analyses showed that post-STEMI patients without left ventricular systolic dysfunction (LVSD) treated with MRA had a 36% reduction in all-cause mortality (RR: 0.64, 95% CI (0.46, 0.89), P = 0.007) and a 22% reduction in cardiovascular adverse events (RR: 0.78, 95% CI (0.67, 0.91), P = 0.002). Meanwhile, post-STEMI patients without LVSD treated with MRA get significant improvements in left ventricular ejection fraction (mean difference (MD): 2.69, 95% CI (2.44, 2.93), P < 0.00001), left ventricular end-systolic index (MD: -4.52 ml/m², 95% CI (-8.21, -0.83), P = 0.02), and left ventricular end-diastolic diameter (MD: -0.11 cm, 95% CI (-0.22, 0.00), P = 0.05). The corresponding RR were 1.72 (95% CI (1.43, 2.07), P < 0.00001) for considered common adverse events (hyperkalemia, gynecomastia, and renal dysfunction).

Conclusions

Our findings suggest that MRA treatment reduces all-cause mortality and cardiovascular adverse events in post-AMI patients, which is more significant in patients after STEMI without LVSD. In addition, MRA treatment may exert beneficial effects on the reversal of cardiac remodeling in patients after STEMI without LVSD.

A patent review of aldosterone synthase inhibitors (2014-present)

INTRODUCTION

Aldosterone synthase (AS) is a key enzyme involved in the final three rate-limiting steps of the biosynthesis pathway of aldosterone, and its inhibition has been considered as an effective strategy to treat hypertension, heart failure, and related cardio-metabolic diseases.

AREA COVERED

This review provides an update on the discovery and development of aldosterone synthase inhibitors by means of patents published between January 2014 and March 2021. The molecules are classified by pharmaceutical company with progress that has been made in clinical trials being highlighted.

EXPERT OPINION

Mineralocorticoid receptor antagonists (MRAs) and aldosterone synthase inhibitors (ASI) represent two of the main approaches for the blockade of aldosterone. Clinical success, as well as foreseen side effects of steroidal MRAs, prompted the discovery and development of ASI. Since the observation of decreased cortisol levels in clinical trials for LCI699, subsequent efforts have been largely focused on improving its selectivity over hCYP11B1. Candidates with improved potency and selectivity are under investigation across a wide range of indications. Whether ASI will provide an additional therapeutic advantage over current safe and selective non-steroidal MRAs is highly anticipated.

The Non-Steroidal Mineralocorticoid Receptor Antagonist KBP-5074 Limits Albuminuria and has Improved Therapeutic Index Compared With Eplerenone in a Rat Model With Mineralocorticoid-Induced Renal Injury

The therapeutic indices (TIs) and efficacy of the non-steroidal mineralocorticoid receptor antagonist (MRA) KBP-5074 and steroidal MRA eplerenone were evaluated in a uninephrectomized Sprague Dawley rat model of aldosterone-mediated renal disease. In two parallel studies, rats were placed on a high-salt diet and received aldosterone by osmotic mini-pump infusion over the course of 27 days. The urinary albumin-to-creatinine ratio (UACR) was evaluated after 7, 14, and 26 days of treatment. Serum K⁺ was evaluated after 14 and 27 days of treatment. Urinary Na⁺, urinary K⁺, and urinary Na⁺/K⁺ ratio were evaluated after 7, 14, and 26 days of treatment. The TI was calculated for each drug as the ratio of the concentration of drug producing 50% of maximum effect (EC₅₀) for increasing serum K⁺ to the EC₅₀ for lowering UACR. The TIs were 24.5 for KBP-5074 and 0.620 for eplerenone, resulting in a 39-fold improved TI for KBP-5074 compared with eplerenone. Aldosterone treatment increased UACR, decreased serum K⁺, and decreased urinary Na⁺ relative to sham-operated controls that did not receive aldosterone infusion in both studies, validating the aldosterone/salt renal injury model. KBP-5074 prevented the increase in UACR at 0.5, 1.5, and 5 mg/kg BID while eplerenone did so only at the two highest doses of 50 and 450 mg/kg BID. Both KBP-5074 and eplerenone blunted the reduction in serum K⁺ seen in the aldosterone treatment group, with significant increases in serum K⁺ at the high doses only (5 mg/kg and 450 mg/kg BID, respectively). Additionally, the urinary Na⁺ and Na⁺/K⁺ ratio significantly increased at the middle and high doses of KBP-5074, but only at the highest dose of eplerenone. These results showed increased TI and efficacy for KBP-5074 compared with eplerenone over a wider therapeutic window.

Mineralocorticoid Receptor Antagonists in Diabetic Kidney Disease

Diabetes mellitus is a global health issue and main cause of chronic kidney disease. Both diseases are also linked through high cardiovascular morbidity and mortality. Diabetic kidney disease (DKD) is present in up to 40% of diabetic patients; therefore, prevention and treatment of DKD are of utmost importance. Much research has been dedicated to the optimization of DKD treatment. In the last few years, mineralocorticoid receptor antagonists (MRA) have experienced a renaissance in this field with the development of non-steroidal MRA. Steroidal MRA have known cardiorenal benefits, but their use is limited by side effects, especially hyperkalemia. Non-steroidal MRA still block the damaging effects of mineralocorticoid receptor overactivation (extracellular fluid volume expansion, inflammation, fibrosis), but with fewer side effects (hormonal, hyperkalemia) than steroidal MRA. This review article summarizes the current knowledge and newer research conducted on MRA in DKD.

DNA Methylation of the Angiotensinogen Gene, AGT, and the Aldosterone Synthase Gene, CYP11B2 in Cardiovascular Diseases

Angiotensinogen (AGT) and aldosterone play key roles in the regulation of blood pressure and are implicated in the pathogenesis of cardiovascular diseases. DNA methylation typically acts to repress gene transcription. The aldosterone synthase gene CYP11B2 is regulated by angiotensin II and potassium. DNA methylation negatively regulates AGT and CYP11B2 expression and dynamically changes in response to continuous promoter stimulation of each gene. High salt intake and excess circulating aldosterone cause DNA demethylation around the CCAAT-enhancer-binding-protein (CEBP) sites of the ATG promoter region, thereby converting the phenotype of AGT expression from an inactive to an active state in visceral adipose tissue and heart. A close association exists between low DNA methylation at CEBP-binding sites and increased AGT expression in salt-sensitive hypertensive rats. Salt-dependent hypertension may be partially affected by increased cardiac AGT expression. CpG dinucleotides in the CYP11B2 promoter are hypomethylated in aldosterone-producing adenomas. Methylation of recognition sequences of transcription factors, including CREB1, NGFIB (NR4A1), and NURR1 (NR4A2) diminish their DNA-binding activity. The methylated CpG-binding protein MECP2 interacts directly with the methylated CYP11B2 promoter. Low salt intake and angiotensin II infusion lead to upregulation of CYP11B2 expression and DNA hypomethylation in the adrenal gland. Treatment with the angiotensin II type 1 receptor antagonist decreases CYP11B2 expression and leads to DNA hypermethylation. A close association between low DNA methylation and increased CYP11B2 expression are seen in the hearts of patients with hypertrophic cardiomyopathy. These results indicate that epigenetic regulation of both AGT and CYP11B2 contribute to the pathogenesis of cardiovascular diseases.

Management of hyperkalemia during treatment with mineralocorticoid receptor blockers: findings from esaxerenone

The nonsteroidal mineralocorticoid receptor (MR) blocker esaxerenone has demonstrated good antihypertensive activity in a variety of patients, including those with uncomplicated grade I-III hypertension, hypertension with moderate renal dysfunction, hypertension with type 2 diabetes mellitus with albuminuria, and hypertension associated with primary aldosteronism. Hyperkalemia has long been recognized as a potential side effect occurring during treatment with MR blockers, but there is a lack of understanding and guidance about the appropriate management of hyperkalemia during antihypertensive therapy with MR blockers, especially in regard to the newer agent esaxerenone. In this article, we first highlight risk factors for hyperkalemia, including advanced chronic kidney disease, diabetes mellitus, cardiovascular disease, age, and use of renin-angiotensin-aldosterone system inhibitors. Next, we examine approaches to prevention and management, including potassium monitoring, diet, and the use of appropriate therapeutic techniques. Finally, we summarize the currently available data for esaxerenone and hyperkalemia. Proper management of serum potassium is required to ensure safe clinical use of MR blockers, including awareness of at-risk patient groups, choosing appropriate dosages for therapy initiation and dosage titration, and monitoring of serum potassium during therapy. It is critical that physicians take such factors into consideration to optimize MR blocker therapy in patients with hypertension.

Phase 1 Studies to Define the Safety, Tolerability, and Pharmacokinetic and Pharmacodynamic Profiles of the Nonsteroidal Mineralocorticoid Receptor Antagonist Apararenone in Healthy Volunteers

Apararenone is a long-acting, nonsteroidal mineralocorticoid receptor antagonist (MRA). The safety, tolerability, and pharmacokinetic (PK) and pharmacodynamic (PD) profiles of single- and multiple-dose apararenone were assessed in 3 phase 1 randomized, double-blind studies in 223 healthy adults. Study 1 assessed the PK, safety/tolerability, and PD of single-dose apararenone (3.75-640 mg) and multiple-dose apararenone (10-40 mg/day on days 1-14, 320 mg loading dose on day 1 + 10 mg/day on days 2-14, or 40-320 mg loading dose on day 1 + 2.5-20 mg/day on days 2-14) in Caucasian and Black men and women. Study 2 assessed the PK and safety of single-dose apararenone (5-320 mg) in healthy Japanese men. Study 3 assessed the PK, PD, and safety/tolerability of single-dose apararenone (160 or 640 mg) or eplerenone (200 mg; only for 160 mg of apararenone), each after fludrocortisone challenge in Caucasian men. In studies 1 and 2, an approximately dose-proportional increase was observed in PK parameters over the apararenone dose range of 3.75-40 mg; at higher doses, a less than dose-proportional increase was observed. Food, sex, age, and race had no apparent effect on apararenone PK. A long half-life was seen for apararenone and its principal metabolite; in addition, the exposure of the metabolite was lower than that of apararenone. Apararenone suppressed the decrease in urinary sodium and potassium ion ratio that occurs after loading with fludrocortisone. These studies support the mechanism of action of apararenone as an MRA, and further clinical development is warranted.

Hypothalamus-pituitary-adrenal Axis in Glucolipid metabolic disorders

With the change of life style, glucolipid metabolic disorders (GLMD) has become one of the major chronic disorders causing public health and clinical problems worldwide. Previous studies on GLMD pay more attention to peripheral tissues. In fact, the central nervous system (CNS) plays an important role in controlling the overall metabolic balance. With the development of technology and the in-depth understanding of the CNS, the relationship between neuro-endocrine-immunoregulatory (NEI) network and metabolism had been gradually illustrated. As the hub of NEI network, hypothalamus-pituitary-adrenal (HPA) axis is important for maintaining the balance of internal environment in the body. The relationship between HPA axis and GLMD needs to be further studied. This review focuses on the role of HPA axis in GLMD and reviews the research progress on drugs for GLMD, with the hope to provide the direction for exploring new drugs to treat GLMD by taking the HPA axis as the target and improve the level of prevention and control of GLMD.

Drug-Drug Interactions of the Nonsteroidal Mineralocorticoid Receptor Antagonist Apararenone With Midazolam, Warfarin, and Digoxin: A Phase 1 Studies in Healthy Volunteers

PURPOSE

To characterize the clinical relevance of in vitro drug-drug interaction findings with apararenone (MT-3995), the effects of apararenone on the sensitive substrates of cytochrome P450 3A4 (midazolam) and 2C9 (warfarin), and P-glycoprotein (digoxin), were assessed through a series of studies conducted in healthy volunteers.

METHODS

Three studies were conducted in 56 healthy adults. Study 1 investigated the effects of the administration of apararenone with midazolam; apararenone was administered on days 2 (320 mg) and days 3-15 (20 mg/d), and midazolam 2 mg, on days 1 and 15. Study 2 investigated the effects of the administration of apararenone with warfarin; apararenone was administered on days 8-11 (40 mg/d) and days 12-27 (10 mg/d), and warfarin 25 mg, on days 1 and 21. Study 3 assessed the effects of the administration of apararenone with digoxin; apararenone was administered on days 11 (160 mg) and days 12-28 (10 mg/d), and digoxin 0.5 mg, on days 1 and 24. Pharmacokinetic parameters included C_max, AUC_0-t, and AUC_0-∞. The safety profile was evaluated based on adverse events from spontaneous reports and clinical findings.

FINDINGS

After the administration of midazolam together with apararenone, compared with midazolam alone, the midazolam ± apararenone treatment ratios (90% CIs) of the geometric least squares (LS) mean C_max, AUC_0-t, and AUC_0-∞ values were 1.263 (1.147-1.392), 1.342 (1.220-1.477), and 1.370 (1.225-1.534), respectively. After the administration of warfarin ± apararenone, the R-warfarin ± apararenone treatment ratios (90% CIs) of the geometric LS mean C_max, AUC_0-t, and AUC_0-∞ values were 1.008 (0.934-1.089), 1.078 (1.029-1.129), and 1.110 (1.056-1.166). Corresponding values for S-warfarin were 1.025 (0.941-1.117), 1.024 (0.979-1.071), and 1.031 (0.984-1.080). After the administration of digoxin ± apararenone, the digoxin ± apararenone treatment ratios (90% CIs) of the geometric LS mean C_max, AUC_0-t, and AUC_0-∞ values were 0.929 (0.789-1.093), 0.894 (0.797-1.033), and 0.887 (0.805-0.977), respectively. Treatment-emergent adverse events were generally of mild to moderate intensity, and no serious adverse events of any kind were reported.

IMPLICATIONS

The findings from this analysis of data from healthy volunteers suggest minimal risk for potential drug-drug interactions between apararenone and other drugs that are likely to be used concurrently in patients. ClinicalTrials.gov identifier: NCT02531568.

Mineralocorticoid receptor antagonists in patients with chronic kidney disease

Mineralocorticoid receptor antagonists (MRA) can reduce cardiovascular morbidity and mortality in patients with heart failure and ischemic heart disease. In addition, these agents have been used in patients with diabetic nephropathy to control proteinuria and slow down chronic kidney disease (CKD) progression. Current guidelines recommend against the use of MRAs in patients with advanced CKD. However, there is growing interest on their use in this population that has unmet needs (high cardiovascular morbidity and mortality) and unique challenges (risk of acute kidney injury or hyperkalemia). This narrative review discusses the emerging role of MRAs for the management of cardiovascular disease and/or the prevention of CKD progression, highlighting results from randomized controlled trials and presenting real-world data from available registries. Results from recent trials in patients on maintenance dialysis are also discussed.

The expanding class of mineralocorticoid receptor modulators: New ligands for kidney, cardiac, vascular, systemic and behavioral selective actions

This paper reviews the class of mineralocorticoid receptor (MR) modulators, especially new nonsteroidal antagonists. MR is a nuclear receptor expressed in many tissues and cell types. Aldosterone, the most important mineralocorticoid hormone and MR agonist, has many unfavorable effects, especially on the heart, blood vessels, and kidneys, by promoting fibrosis and tissue remodelling. Classical synthetic MR antagonists (spironolactone, eplerenone) have proven useful in clinical practice through their antihypertensive effects in resistant forms, and through benefits on morbidity and mortality in heart failure with reduced ejection fraction. These benefits are associated with important side effects, hyperkalemia being the main limitation. In the latest years, a new generation of MR modulators with a nonsteroidal structure has emerged. These compounds are more selective than classical MR antagonists, with much higher affinity for the MR than for the glucocorticoid, androgen, or progesterone receptors. Recent clinical and experimental observations suggest that nonsteroidal MR antagonists, especially finerenone, have proven superior renoprotective properties, antiproteinuric efficacy, inhibition of inflammation and heart fibrosis in animal models, without sharing the side effects of steroidal MR antagonists. Nonsteroidal MR modulators represent an interesting new therapeutic approach for the prevention and progression of chronic kidney disease and for patients with heart failure and renal disease. Despite these promising data, there are still many issues to be clarified and it is necessary to accumulate solid evidence from studies on larger numbers of patients and from head-to-head clinical trials.