Cardioprotective Effects of a Nonsteroidal Mineralocorticoid Receptor Blocker, Esaxerenone, in Dahl Salt-Sensitive Hypertensive Rats

Mineralocorticoid Receptor Blocker Prevents Mineralocorticoid Receptor-Mediated Inflammation by Modulating Transcriptional Activity of Mineralocorticoid Receptor-p65-Signal Transducer and Activator of Transcription 3 Complex

BACKGROUND

Mineralocorticoid receptor (MR) induces cardiac inflammation cooperatively with nuclear factor-κB and signal transducer and activator of transcription 3 (STAT3); MR blockers exert anti-inflammatory effects. However, the underlying mechanism remains unclear. We investigated the anti-inflammatory effect of esaxerenone, a novel MR blocker, in experimental myocardial infarction (MI) and its underlying mechanisms.

METHODS AND RESULTS

Male C57BL/6J mice subjected to ligation of the left anterior descending artery were randomly assigned to either the vehicle or esaxerenone group. Esaxerenone was provided with a regular chow diet. The mice were euthanized at either 4 or 15 days after MI. Cardiac function, fibrosis, and inflammation were evaluated. Esaxerenone significantly improved cardiac function and attenuated cardiac fibrosis at 15 days after MI independently of its antihypertensive effect. Inflammatory cell infiltration, inflammatory-related gene expression, and elevated serum interleukin-6 levels at 4 days after MI were significantly attenuated by esaxerenone. In vitro experiments using mouse macrophage-like cell line RAW264.7 cells demonstrated that esaxerenone- and spironolactone-attenuated lipopolysaccharide-induced interleukin-6 expression without altering the posttranslational modification and nuclear translocation of p65 and STAT3. Immunoprecipitation assays revealed that MR interacted with both p65 and STAT3 and enhanced the p65-STAT3 interaction, leading to a subsequent increase in interleukin-6 promoter activity, which was reversed by esaxerenone.

CONCLUSIONS

Esaxerenone ameliorated postinfarct remodeling in experimental MI through its anti-inflammatory properties exerted by modulating the transcriptional activity of the MR-p65-STAT3 complex. These results suggest that the MR-p65-STAT3 complex can be a novel therapeutic target for treating MI.

The Participation of Ferroptosis in Fibrosis of the Heart and Kidney Tissues in Dahl Salt-Sensitive Hypertensive Rats

BACKGROUND

Salt-sensitive hypertension is often more prone to induce damage to target organs such as the heart and kidneys. Abundant recent studies have demonstrated a close association between ferroptosis and cardiovascular diseases. Therefore, we hypothesize that ferroptosis may be closely associated with organ damage in salt-sensitive hypertension. This study aimed to investigate whether ferroptosis is involved in the occurrence and development of myocardial fibrosis and renal fibrosis in salt-sensitive hypertensive rats.

METHODS

Ten 7-week-old male Dahl salt-sensitive (Dahl-SS) rats were adaptively fed for 1 week, then randomly divided into two groups and fed either a normal diet (0.3% NaCl, normal diet group) or a high-salt diet (8% NaCl, high-salt diet group) for 8 weeks. Blood pressure of the rats was observed, and analysis of the hearts and kidneys of Dahl-SS rats was conducted via hematoxylin-eosin (HE) staining, Masson staining, Prussian blue staining, transmission electron microscopy, tissue iron content detection, malondialdehyde content detection, immunofluorescence, and Western blot.

RESULTS

Compared to the normal diet group, rats in the high-salt diet group had increases in systolic blood pressure and diastolic blood pressure (P < 0.05); collagen fiber accumulation was observed in the heart and kidney tissues (P < 0.01), accompanied by alterations in mitochondrial ultrastructure, reduced mitochondrial volume, and increased density of the mitochondrial double membrane. Additionally, there were significant increases in both iron content and malondialdehyde levels (P < 0.05). Immunofluorescence and Western blot results both indicated significant downregulation (P < 0.05) of xCT and GPX4 proteins associated with ferroptosis in the high-salt diet group.

CONCLUSIONS

Ferroptosis is involved in the damage and fibrosis of the heart and kidney tissues in salt-sensitive hypertensive rats.

Esaxerenone: blood pressure reduction and cardiorenal protection without reflex sympathetic activation in salt-loaded stroke-prone spontaneously hypertensive rats

Mineralocorticoid receptor (MR) is involved in the mechanisms of blood pressure elevation, organ fibrosis, and inflammation. MR antagonists have been used in patients with hypertension, heart failure, or chronic kidney disease. Esaxerenone, a recently approved MR blocker with a nonsteroidal structure, has demonstrated a strong blood pressure-lowering effect. However, blood pressure reduction may lead to sympathetic activation through the baroreflex. The effect of esaxerenone on the sympathetic nervous system remains unclear. We investigated the effect of esaxerenone on organ damage and the sympathetic nervous system in salt-loaded stroke-prone spontaneously hypertensive rats (SHRSP), a well-established model of essential hypertension with sympathoexcitation and organ damage. Three-week administration of esaxerenone or hydralazine successfully attenuated the blood pressure elevation. Both esaxerenone and hydralazine comparably suppressed left ventricular hypertrophy and urinary albumin excretion. However, renal fibrosis and glomerular sclerosis were suppressed by esaxerenone but not hydralazine. Furthermore, plasma norepinephrine level, a parameter of systemic sympathetic activity, was significantly increased by hydralazine but not by esaxerenone. Consistent with these findings, the activity of the control centers of sympathetic nervous system, the parvocellular region of the paraventricular nucleus in the hypothalamus and the rostral ventrolateral medulla, was enhanced by hydralazine but remained unaffected by esaxerenone. These results suggest that esaxerenone effectively lowers blood pressure without inducing reflex sympathetic nervous system activation. Moreover, the organ-protective effects of esaxerenone appear to be partially independent of its blood pressure-lowering effect. In conclusion, esaxerenone demonstrates a blood pressure-lowering effect without concurrent sympathetic activation and exerts organ-protective effects in salt-loaded SHRSP. Esaxerenone has antihypertensive and cardiorenal protective effects without reflex sympathetic activation in salt-loaded stroke-prone spontaneously hypertensive rats.

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).

Additive Effects of Esaxerenone, a Nonsteroidal Mineralocorticoid Receptor Blocker, on Cardioplegic Arrest in Rat Hearts

PURPOSE

Esaxerenone, a mineralocorticoid receptor blocker, attenuates global ischemia-induced myocardial damage and coronary endothelial dysfunction. This study aimed to determine whether esaxerenone exerted cardioprotective effects against cardioplegic arrest in Wistar rat hearts.

METHODS

Isolated male Wistar rat hearts aerobically perfused via the Langendorff method for 20 min were randomly allocated to the Control (n = 6; perfused for an additional 10 min and subjected to no treatment) or Esax (n = 6; perfused with 0.1 μmol/L esaxerenone in perfusate for 10 min before ischemia) groups. Hearts in both groups were perfused with St. Thomas' Hospital No. 2 solution (STH2) for 2 min and subjected to 28 min of global ischemia. The recovery of left ventricular developed pressure (LVDP) and total troponin T leakage were measured after reperfusion.

RESULTS

The final recovery of LVDP (expressed as a percentage of pre-ischemic value) in the Control and Esax groups was 50.8 ± 3.5% and 62.1 ± 5.6%, respectively (p <0.05, Esax vs. Control). The total troponin T leakage in the Control and Esax groups was 138.8 ± 18.5 ng/g heart wt and 74.3 ± 18.6 ng/g heart wt, respectively (p <0.05, Esax vs. Control).

CONCLUSION

The administration of esaxerenone before cardioplegic arrest enhanced the cardioprotective effect exerted by STH2.

Investigating the Impact of Selective Modulators on the Renin-Angiotensin-Aldosterone System: Unraveling Their Off-Target Perturbations of Transmembrane Ionic Currents

The renin-angiotensin-aldosterone system (RAAS) plays a crucial role in maintaining various physiological processes in the body, including blood pressure regulation, electrolyte balance, and overall cardiovascular health. However, any compounds or drugs known to perturb the RAAS might have an additional impact on transmembrane ionic currents. In this retrospective review article, we aimed to present a selection of chemical compounds or medications that have long been recognized as interfering with the RAAS. It is noteworthy that these substances may also exhibit regulatory effects in different types of ionic currents. Apocynin, known to attenuate the angiotensin II-induced activation of epithelial Na+ channels, was shown to stimulate peak and late components of voltage-gated Na+ current (INa). Esaxerenone, an antagonist of the mineralocorticoid receptor, can exert an inhibitory effect on peak and late INa directly. Dexamethasone, a synthetic glucocorticoid, can directly enhance the open probability of large-conductance Ca2+-activated K+ channels. Sparsentan, a dual-acting antagonist of the angiotensin II receptor and endothelin type A receptors, was found to suppress the amplitude of peak and late INa effectively. However, telmisartan, a blocker of the angiotensin II receptor, was effective in stimulating the peak and late INa along with a slowing of the inactivation time course of the current. However, telmisartan's presence can also suppress the erg-mediated K+ current. Moreover, tolvaptan, recognized as an aquaretic agent that can block the vasopressin receptor, was noted to suppress the amplitude of the delayed-rectifier K+ current and the M-type K+ current directly. The above results indicate that these substances not only have an interference effect on the RAAS but also exert regulatory effects on different types of ionic currents. Therefore, to determine their mechanisms of action, it is necessary to gain a deeper understanding.

Potential Impact of Non-Steroidal Mineralocorticoid Receptor Antagonists in Cardiovascular Disease

Inappropriate mineralocorticoid receptor (MR) activation in different cardiovascular cell types has deleterious effects on cardiac remodeling and function. Therefore, MR inhibition is a crucial pharmacological strategy to overcome cardiovascular dysfunction. Despite efficient blockade of MR with steroidal MR antagonists (MRAs), their clinical application is unsatisfactory due to the adverse effects. Newer non-steroidal MRAs with greater potency could be suitable for clinical application, especially in patients with type 2 diabetes mellitus and chronic kidney disease. Although clinical evidence has shown the beneficial effects of non-steroidal MRAs on cardiovascular outcomes in patients with heart failure with reduced ejection fraction, clinical trials are ongoing to evaluate the efficacy of heart failure with preserved ejection fraction. Therefore, comparative pharmacological characterization of non-steroidal MRAs over classic steroidal MRAs is crucial. Here, we summarize the pre-clinical evidence of non-steroidal MRAs, which suggests an improvement in cardiac dysfunction, as well as the underlying molecular mechanisms in animal models mimicking different clinical conditions. In addition, we discuss up-to-date information from clinical trials regarding the beneficial effects of non-steroidal MRAs on meaningful cardiovascular outcomes. Both pre-clinical and clinical evidence support treatment with non-steroidal MRAs in patients with cardiovascular disease.

Importance of Micromilieu for Pathophysiologic Mineralocorticoid Receptor Activity-When the Mineralocorticoid Receptor Resides in the Wrong Neighborhood

The mineralocorticoid receptor (MR) is a member of the steroid receptor family and acts as a ligand-dependent transcription factor. In addition to its classical effects on water and electrolyte balance, its involvement in the pathogenesis of cardiovascular and renal diseases has been the subject of research for several years. The molecular basis of the latter has not been fully elucidated, but an isolated increase in the concentration of the MR ligand aldosterone or MR expression does not suffice to explain long-term pathologic actions of the receptor. Several studies suggest that MR activity and signal transduction are modulated by the surrounding microenvironment, which therefore plays an important role in MR pathophysiological effects. Local changes in micromilieu, including hypoxia, ischemia/reperfusion, inflammation, radical stress, and aberrant salt or glucose concentrations affect MR activation and therefore may influence the probability of unphysiological MR actions. The surrounding micromilieu may modulate genomic MR activity either by causing changes in MR expression or MR activity; for example, by inducing posttranslational modifications of the MR or novel interaction with coregulators, DNA-binding sites, or non-classical pathways. This should be considered when developing treatment options and strategies for prevention of MR-associated diseases.

Association of Antihypertensive Effects of Esaxerenone with the Internal Sodium Balance in Dahl Salt-Sensitive Hypertensive Rats

Background: The nonsteroidal mineralocorticoid receptor blocker esaxerenone is effective in reducing blood pressure (BP). Objective: In this study, we investigated esaxerenone-driven sodium homeostasis and its association with changes in BP in Dahl salt-sensitive (DSS) hypertensive rats. Methods: In the different experimental setups, we evaluated BP by a radiotelemetry system, and sodium homeostasis was determined by an approach of sodium intake (food intake) and excretion (urinary excretion) in DSS rats with a low-salt diet (0.3% NaCl), high-salt diet (HSD, 8% NaCl), HSD plus 0.001% esaxerenone (w/w), and HSD plus 0.05% furosemide. Results: HSD-fed DSS rats showed a dramatic increase in BP with a non-dipper pattern, while esaxerenone treatment, but not furosemide, significantly reduced BP with a dipper pattern. The cumulative sodium excretion in the active period was significantly elevated in esaxerenone- and furosemide-treated rats compared with their HSD-fed counterparts. Sodium content in the skin, skinned carcass, and total body tended to be lower in esaxerenone-treated rats than in their HSD-fed counterparts, while these values were unchanged in furosemide-treated rats. Consistently, sodium balance tended to be reduced in esaxerenone-treated rats during the active period. Histological evaluation showed that esaxerenone, but not furosemide, treatment attenuated glomerulosclerosis, tubulointerstitial fibrosis, and urinary protein excretion induced by high salt loading. Conclusions: Collectively, these findings suggest that an esaxerenone treatment-induced reduction in BP and renoprotection are associated with body sodium homeostasis in salt-loaded DSS rats.

Non-steroidal mineralocorticoid receptor antagonists in cardiorenal disease

Despite existing treatments, patients with heart failure and chronic kidney disease (CKD) remain at high risk for adverse outcomes and progression to end-stage disease. Steroidal mineralocorticoid receptor antagonists (MRAs) such as spironolactone and eplerenone reduce mortality but remain under-prescribed due to the perceived risk of hyperkalaemia and hormonal side effects. The discovery of non-steroidal MRAs represents a major new dimension in cardiorenal disease therapy. Non-steroidal MRAs have high affinity and specificity for the mineralocorticoid receptor (MR) and differ from both steroidal agents and each other with respect to important physiochemical, pharmacodynamic, and pharmacokinetic parameters. Similar to their steroidal counterparts, they have beneficial anti-inflammatory, anti-remodelling, and anti-fibrotic properties in the kidneys, heart, and vasculature. There are several non-steroidal MRAs under development and clinical assessment; of these, only esaxerenone and finerenone are approved for treatment globally. In Japan, esaxerenone is approved for essential hypertension and has been studied in diabetic nephropathy. Compared with steroidal MRAs, finerenone more potently inhibits MR co-regulator recruitment and fibrosis and distributes more evenly between the heart and kidneys. The landmark Phase III trials FIGARO-DKD and FIDELIO-DKD demonstrated that finerenone-reduced major kidney and cardiovascular events on top of maximally tolerated renin-angiotensin-aldosterone system inhibition in patients with CKD associated with Type 2 diabetes. Non-steroidal MRAs are currently under evaluation in heart failure and for synergistic treatment with sodium-glucose contransporter 2 inhibitors. These ground-breaking agents could become an important therapy across the spectrum of cardiorenal disease.

Implication of Mineralocorticoid Receptor Antagonist Esaxerenone in Patients With Heart Failure With Preserved Ejection Fraction

Background: The implications of mineralocorticoid receptor antagonists, including the newly introduced esaxerenone, on cardiac reverse remodeling in patients with heart failure with preserved ejection fraction (HFpEF) remain uncertain. Methods and Results: We included patients with HFpEF who received esaxerenone for hypertension between November 2019 and July 2021 in this retrospective study. Changes in left ventricular mass index (LVMI) were compared between the 6-month pretreatment period (without esaxerenone) and the 6-month treatment period (on esaxerenone). Thirty-three patients (median age 74 years [interquartile range {IQR} 70-81 years]; 33% male, median systolic blood pressure [SBP] 135 mmHg [IQR 123-148 mmHg]) were included in the study and completed 6-month esaxerenone therapy without any adverse events. During the pretreatment period, SBP decreased significantly (P=0.009), whereas LVMI remained unchanged (P=0.30). During the esaxerenone treatment period, both SBP and LVMI decreased significantly (P=0.003 and P=0.001, respectively). Conclusions: Esaxerenone may have beneficial effects of reverse remodeling in patients with HFpEF when used to treat hypertension. Further studies are needed to understand which patient populations may see greater benefits with esaxerenone.

The Role of the Mineralocorticoid Receptor and Mineralocorticoid Receptor-Directed Therapies in Heart Failure

Mineralocorticoid receptor (MR) antagonists (MRA), also referred to as aldosterone blockers, are now well-recognized for their clinical benefit in patients who have heart failure (HF) with reduced ejection fraction (HFrEF). Recent studies have also shown MRA can improve outcomes in patients with HFpEF, where the ejection fraction is preserved but left ventricular filling is reduced. While the MR is a steroid hormone receptor best known for antinatriuretic actions on electrolyte homeostasis in the distal nephron, it is now established that the MR has many physiological and pathophysiological roles in the heart, vasculature, and other nonepithelial tissue types. It is the impact of MR activation on these tissues that underpins the use of MRA in cardiovascular disease, in particular HF. This mini-review will discuss the origins and the development of MRA and highlight how their use has evolved from the "potassium-sparing diuretics" spironolactone and canrenone over 60 years ago, to the more receptor-selective eplerenone and most recently the emergence of new nonsteroidal receptor antagonists esaxerenone and finerenone.

Characterization of Direct Perturbations on Voltage-Gated Sodium Current by Esaxerenone, a Nonsteroidal Mineralocorticoid Receptor Blocker

Esaxerenone (ESAX; CS-3150, Minnebro^®) is known to be a newly non-steroidal mineralocorticoid receptor (MR) antagonist. However, its modulatory actions on different types of ionic currents in electrically excitable cells remain largely unanswered. The present investigations were undertaken to explore the possible perturbations of ESAX on the transient, late and persistent components of voltage-gated Na⁺ current (I_Na) identified from pituitary GH₃ or MMQ cells. GH₃-cell exposure to ESAX depressed the transient and late components of I_Na with varying potencies. The IC₅₀ value of ESAX required for its differential reduction in peak or late I_Na in GH₃ cells was estimated to be 13.2 or 3.2 μM, respectively. The steady-state activation curve of peak I_Na remained unchanged during exposure to ESAX; however, recovery of peak I_Na block was prolonged in the presence 3 μM ESAX. In continued presence of aldosterone (10 μM), further addition of 3 μM ESAX remained effective at inhibiting I_Na. ESAX (3 μM) potently reversed Tef-induced augmentation of I_Na. By using isosceles-triangular ramp pulse with varying durations, the amplitude of persistent I_Na measured at high or low threshold was enhanced by the presence of tefluthrin (Tef), in combination with the appearance of the figure-of-eight hysteretic loop; moreover, hysteretic strength of the current was attenuated by subsequent addition of ESAX. Likewise, in MMQ lactotrophs, the addition of ESAX also effectively decreased the peak amplitude of I_Na along with the increased current inactivation rate. Taken together, the present results provide a noticeable yet unidentified finding disclosing that, apart from its antagonistic effect on MR receptor, ESAX may directly and concertedly modify the amplitude, gating properties and hysteresis of I_Na in electrically excitable cells.