Rationale for an early aldosterone blockade in acute myocardial infarction and design of the ALBATROSS trial

Serum Aldosterone as Predictor of Progression of Coronary Heart Disease in Patients Without Signs of Heart Failure After Acute Myocardial Infarction

Introduction:

In patients with acute myocardial infarction (AMI) early risk assessment of development of complications is of great importance. It is proven that aldosterone level has a major role in progression of cardiovascular pathology.

Aim:

Determination of influence of aldosterone plasma level in the progression of heart disease in patients without signs of heart failure after AMI.

Material and Methods:

Research included 207 patients, hospitalized in the acute phase of myocardial infarction, and who were divided into two groups: 127 patients with no clinical signs of heart failure and 60 patients with heart failure.

Results:

The serum aldosterone concentration was 73.4% higher in the group of decompensated patients, 128 pg/mL (75.4-236 pg/mL) in decompensated and 73.7 pg/mL (42.7 -115.25 pg/mL) in compensated. In the group of compensated patients, changes in aldosterone levels showed a statistically significant effect on the incidence of post-infarction angina (p=0.0001) as well as reinfarction (p=0.009). There is a connection between changes in aldosterone plasma level and positive stress test (p=0.012).

Conclusion:

In patients with AMI, elevated serum aldosterone level can be prognostic factor of the progression of coronary heart disease, development of heart failure, as well of development of post-infarction angina, myocardial reinfarction and pathological finding on the stress test.

Mineralocorticoid receptor antagonist pre-treatment and early post-treatment to minimize reperfusion injury after ST-elevation myocardial infarction: The MINIMIZE STEMI trial

Background

Mineralocorticoid receptor antagonist (MRA) therapy has been shown to prevent adverse left ventricular (LV) remodeling in ST-segment elevation myocardial infarction (STEMI) patients with heart failure. Whether initiating MRA therapy prior to primary percutaneous coronary intervention (PPCI) accrues additional benefit of reducing myocardial infarct size and preventing adverse LV remodeling is not known. We aimed to investigate whether MRA therapy initiated prior to reperfusion reduces myocardial infarct (MI) size and prevents adverse LV remodeling in STEMI patients.

Methods

STEMI patients presenting within 12 hours and with a proximal coronary artery occlusion with Thrombolysis In Myocardial Infarction flow grade 0 were consented and randomized to either an intravenous bolus of potassium canrenoate, followed by oral spironolactone for 3 months or matching placebo. The primary endpoint was MI size by cardiovascular magnetic resonance at 3 months.

Results

Sixty-seven patients completed the study. There was no significant difference in the final MI size at 3 months between the 2 groups (placebo: 17 ± 11%, MRA: 16 ± 10%, P = .574). There was also no difference in acute MI size (26 ± 16% versus 23 ± 14%, P = .425) or myocardial salvage (26 ± 12% versus 24 ± 8%, P = .456). At follow-up, there was a trend towards an improvement in LVEF (placebo: 49 ± 8%, MRA: 54 ± 11%, P = .053), and the MRA group had significantly greater percentage decrease in LVEDV (mean difference: −12.2 (95% CI −20.3 to −4.4)%, P = .003) and LVESV (mean difference: −18.2 (95% CI −30.1 to −6.3)%, P = .003).

Conclusion

This pilot study showed no benefit of MRA therapy in reducing MI size in STEMI patients when initiated prior to reperfusion, but there was an improvement in LV remodeling at 3 months. Adequately powered studies are warranted to confirm these findings.

Integration of Metabolomics With Pharmacodynamics to Elucidate the Anti-myocardial Ischemia Effects of Combination of Notoginseng Total Saponins and Safflower Total Flavonoids

Notoginseng (Sanqi), the roots and rhizomes of Panax notoginseng and safflower, the flowers of Carthamus tinctorius, are widely used traditional Chinese medicines (TCMs) for the treatment of cardiovascular diseases. Positive evidences have fueled growing acceptance for cardioprotective effects of the combination of the notoginseng total saponins and safflower total flavonoids (CNS) against myocardial ischemia (MI). However, the underlying cardioprotective mechanisms of CNS are still obscured. Metabolomics is a comprehensive tool for investigating biological mechanisms of disease, monitoring therapeutic outcomes, and advancing drug discovery and development. Herein, we investigated the cardioprotective effects of CNS on the isoproterenol (ISO)-induced MI rats by using plasma and urine metabolomics based on ultra-performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry (UPLC-Q-TOF/MS) and multiple pharmacodynamics approaches. The results showed that pretreatment with CNS could attenuate the cardiac injury resulting from ISO, as evidenced by decreasing the myocardial infarct size, converting the echocardiographic, histopathological, and plasma biochemical abnormalities, and reversing the perturbations of plasma and urine metabolic profiles, particularly for the 55.0 mg/kg dosage group. In addition, 44 metabolites were identified as the potential MI biomarkers, mainly including a range of free fatty acids (FFAs), sphingolipids, and glycerophospholipids. CNS pretreatment group may robustly ameliorate these potential MI-related biomarkers. The accumulation of LysoPCs and FFAs, caused by PLA₂, may activate NF-κB pathway and increase proinflammatory cytokines. However, our results showed that CNS at 55.0 mg/kg dosage could maximally attenuate the NF-κB signaling pathway, depress the expressions of TNF-α, IL-6, IL-1β, and PLA₂. The results suggested that the anti-inflammatory property of CNS may contribute to its cardioprotection against MI. Our results demonstrate that the integrating of metabolomics with pharmacodynamics provides a reasonable approach for understanding the therapeutic effects of TCMs and CNS provide a potential candidate for prevention and treatment of MI.

Third-generation Mineralocorticoid Receptor Antagonists: Why Do We Need a Fourth?

The first mineralocorticoid receptor (MR) antagonist, spironolactone, was developed almost 60 years ago to treat primary aldosteronism and pathological edema. Its use waned in part because of its lack of selectivity. Subsequently, knowledge of the scope of MR function was expanded along with clinical evidence of the therapeutic importance of MR antagonists to prevent the ravages of inappropriate MR activation. Forty-two years elapsed between the first and MR-selective second generation of MR antagonists. Fifteen years later, despite serious shortcomings of the existing antagonists, a third-generation antagonist has yet to be marketed. Progress has been slowed by the lack of appreciation of the large variety of cell types that express the MR and its diverse cell-type-specific actions, and also its unique complex interaction actions at the molecular level. New MR antagonists should preferentially target the inflammatory and fibrotic effects of MR and perhaps its excitatory effects on sympathetic nervous system, but not the renal tubular epithelium or neurons of the cortex and hippocampus. This review briefly describes efforts to develop a third-generation MR antagonist and why fourth generation antagonists and selective agonists based on structural determinants of tissue and ligand-specific MR activation should be contemplated.

Early Aldosterone Blockade in Acute Myocardial Infarction: The ALBATROSS Randomized Clinical Trial

BACKGROUND

Mineralocorticoid receptor antagonists (MRA) improve outcome in the setting of post-myocardial infarction (MI) heart failure (HF).

OBJECTIVES

The study sought to assess the benefit of an early MRA regimen in acute MI irrespective of the presence of HF or left ventricular (LV) dysfunction.

METHODS

We randomized 1,603 patients to receive an MRA regimen with a single intravenous bolus of potassium canrenoate (200 mg) followed by oral spironolactone (25 mg once daily) for 6 months in addition to standard therapy or standard therapy alone. The primary outcome of the study was the composite of death, resuscitated cardiac arrest, significant ventricular arrhythmia, indication for implantable defibrillator, or new or worsening HF at 6-month follow-up. Key secondary/safety outcomes included death and other individual components of the primary outcome and rates of hyperkalemia at 6 months.

RESULTS

The primary outcome occurred in 95 (11.8%) and 98 (12.2%) patients in the treatment and control groups, respectively (hazard ratio [HR]: 0.97; 95% confidence interval [CI]: 0.73 to 1.28). Death occurred in 11 (1.4%) and 17 (2.1%) patients in the treatment and control groups, respectively (HR: 0.65; 95% CI: 0.30 to 1.38). In a non-pre-specified exploratory analysis, the odds of death were reduced in the treatment group (3 [0.5%] vs. 15 [2.4%]; HR: 0.20; 95% CI: 0.06 to 0.70) in the subgroup of ST-segment elevation MI (n = 1,229), but not in non-ST-segment elevation MI (p for interaction = 0.01). Hyperkalemia >5.5 mmol/l(-1) occurred in 3% and 0.2% of patients in the treatment and standard therapy groups, respectively (p < 0.0001).

CONCLUSIONS

The study failed to show the benefit of early MRA use in addition to standard therapy in patients admitted for MI. (Aldosterone Lethal effects Blockade in Acute myocardial infarction Treated with or without Reperfusion to improve Outcome and Survival at Six months follow-up; NCT01059136).

Mineralocorticoid receptor antagonist pretreatment to MINIMISE reperfusion injury after ST-elevation myocardial infarction (the MINIMISE STEMI Trial): rationale and study design

Novel therapies capable of reducing myocardial infarct (MI) size when administered prior to reperfusion are required to prevent the onset of heart failure in ST‐segment elevation myocardial infarction (STEMI) patients treated by primary percutaneous coronary intervention (PPCI). Experimental animal studies have demonstrated that mineralocorticoid receptor antagonist (MRA) therapy administered prior to reperfusion can reduce MI size, and MRA therapy prevents adverse left ventricular (LV) remodeling in post‐MI patients with LV impairment. With these 2 benefits in mind, we hypothesize that initiating MRA therapy prior to PPCI, followed by 3 months of oral MRA therapy, will reduce MI size and prevent adverse LV remodeling in STEMI patients. The MINIMISE‐STEMI trial is a prospective, randomized, double‐blind, placebo‐controlled trial that will recruit 150 STEMI patients from four centers in the United Kingdom. Patients will be randomized to receive either an intravenous bolus of MRA therapy (potassium canrenoate 200 mg) or matching placebo prior to PPCI, followed by oral spironolactone 50 mg once daily or matching placebo for 3 months. A cardiac magnetic resonance imaging scan will be performed within 1 week of PPCI and repeated at 3 months to assess MI size and LV remodeling. Enzymatic MI size will be estimated by the 48‐hour area‐under‐the‐curve serum cardiac enzymes. The primary endpoint of the study will be MI size on the 3‐month cardiac magnetic resonance imaging scan. The MINIMISE STEMI trial will investigate whether early MRA therapy, initiated prior to reperfusion, can reduce MI size and prevent adverse post‐MI LV remodeling.

Spironolactone Regulates HCN Protein Expression Through Micro-RNA-1 in Rats With Myocardial Infarction

Emerging evidence has shown that aldosterone blockers reduced the incidence of ventricular arrhythmias in patients with myocardial infarction (MI). However, the mechanism remains unknown. In this study, we investigated the mechanism by which spironolactone, a classic aldosterone blocker, regulates hyperpolarization-activated cyclic nucleotide-gated channel (HCN) protein expression in ischemic rat myocardium after MI. Eighteen rats surviving 24 hours after MI were randomly assigned into 3 groups: MI, spironolactone, and spironolactone + antagomir-1. Six sham-operated rats had a suture loosely tied around the left coronary artery, without ligation. The border zone of the myocardial infarct was collected from each rat at 1 week after MI. HCN2 and HCN4 protein and messenger RNA (mRNA) level were measured in addition to miRNA-1 levels. Spironolactone significantly increased miRNA-1 levels and downregulated HCN2 and HCN4 protein and mRNA levels. miRNA-1 suppression with antagomir-1 increased HCN2 and HCN4 protein levels; however, HCN2 and HCN4 mRNA levels were not affected. These results suggested that spironolactone could increase miRNA-1 expression in ischemic rat myocardium after MI and that the upregulation of miRNA-1 expression partially contributed to the posttranscriptional repression of HCN protein expression, which may contribute to the effect of spironolactone to reduce the incidence of MI-associated ventricular arrhythmias.

Efficacy of mineralocorticoid receptor antagonism in the acute myocardial infarction phase: eplerenone versus spironolactone

AIMS

The selective mineralocorticoid receptor (MR) antagonist eplerenone given early in patients with acute myocardial infarction (MI) improves clinical outcome, whereas little is known about the effectiveness of early spironolactone therapy. We aimed to compare the ability of eplerenone and spironolactone to promote cardiac repair after experimental MI.

METHODS AND RESULTS

Starting immediately after coronary artery ligation, C57BL/6J mice were treated with placebo, eplerenone, or spironolactone. At 7 days, treatment with eplerenone or spironolactone reduced thinning and expansion of healing infarct and improved early left ventricular chamber enlargement. Remarkably, eplerenone therapy resulted in significantly greater improvement than spironolactone of left ventricular contractile function and relaxation, associated with a more considerable leftward and downward shift of the pressure volume curve. Seven-day survival rate was significantly increased only in eplerenone treated mice. Moreover, eplerenone was superior to spironolactone in ameliorating neovessel formation in the injured myocardium. Optimized flow cytometry analysis of the monocyte differentiation marker Ly6C revealed predominant accumulation of Ly6Chigh monocytes/macrophages at the site of ischemic injury during the early inflammatory phase in placebo-treated mice. In contrast, MR antagonism, especially by eplerenone, led to a skewing of the monocyte/macrophage population toward a higher frequency of healing promoting Ly6Clow cells.

CONCLUSION

The MR antagonist eplerenone versus spironolactone showed superior efficacy during the acute MI phase with more beneficial effects on survival, early cardiac dilation, and functional decline. Modulation of monocyte maturation and enhanced infarct neovessel formation appears to play a pivotal role.

Emerging cardiovascular indications of mineralocorticoid receptor antagonists

Mineralocorticoid receptor (MR) antagonism is a well-established treatment modality for patients with hypertension, heart failure, and left ventricular systolic dysfunction (LVSD) post-myocardial infarction (MI). There are emerging data showing potential benefits of MR antagonists in other cardiovascular conditions. Studies have shown association between MR activation and the development of myocardial fibrosis, coronary artery disease, metabolic syndrome, and cerebrovascular diseases. This review examines the preclinical and clinical data of MR antagonists for novel indications including heart failure with preserved ejection fraction (HFPEF), pulmonary arterial hypertension (PAH), arrhythmia, sudden cardiac death, valvular heart disease, metabolic syndrome, renal disease, and stroke. MR antagonists are not licensed for these conditions yet; however, emerging data suggest that indication for MR antagonists are likely to broaden; further studies are warranted.

Electrophysiological and antiarrhythmic properties of potassium canrenoate during myocardial ischemia-reperfusion

INTRODUCTION

Recent clinical studies have reported the potential benefit of an early mineralocorticoid receptor (MR) blockade with potassium canrenoate (PC) on ventricular arrhythmias (VAs) occurrence in patients experiencing an ST-segment elevation myocardial infarction (STEMI). However, most of the electrophysiological properties of PC demonstrated to date have been investigated in normoxic conditions, and therefore, in vitro experiments during an acute myocardial ischemia-reperfusion were lacking.

MATERIALS AND METHODS

We used rabbit in vitro models and standard microelectrode technique to assess the electrophysiological impact of PC during myocardial ischemia-reperfusion, including right ventricle mimicking the "border zone" existing between normal and ischemic/reperfused areas (1 µmol/L, 10 and 100 nmol/L), isolated right ventricle, and sinoatrial node (SAN) experiments (1 µmol/L, respectively).

RESULTS

During ischemia-reperfusion, acute superfusion of PC 100 nmol/L prevented the increase in action potential (AP) duration at 90% of repolarization (APD90) dispersion between ischemic and nonischemic areas and in VAs occurrence induced by aldosterone 10 nmol/L (86 ± 3 vs 114 ± 4 milliseconds for aldosterone alone, P < .05). Potassium canrenoate also induced conduction blocks and significantly decreased Vmax during simulated ischemia (from 25 ± 5 to 12 ± 4, 14 ± 3, and 14 ± 5 V/s, respectively, for PC 1 µmol/L, 100, and 10 nmol/L, P < .05). Potassium canrenoate 1 µmol/L demonstrated cycle length (CL)-dependent effects on APD90 and on Vmax, and it also reduced SAN beating CL (from 446 ± 28 to 529 ± 24 millisecond, P < .05).

CONCLUSION

Our experimental study highlights new evidence for an antiarrhythmic impact of PC during myocardial ischemia-reperfusion via multiple channels modulation. These results are in line with recent clinical trials suggesting that an early MR blockade in STEMI may be preventive of VAs.

Pathophysiology and the cardiorenal connection in heart failure. Circulating hormones: biomarkers or mediators

Heart failure (HF) is a syndrome characterized by a complex pathophysiology which involves multiple organ systems, with the kidney playing a major role. HF can present with reduced ejection fraction (EF), HFrEF, or with preserved EF (HFpEF). The interplay between diverse organ systems contributing to HF is mediated by the activation of counteracting neurohormonal pathways focused to re-establishing hemodynamic homeostasis. During early stages of HF, these biochemical signals, consisting mostly of hormones and neurotransmitters secreted by a variety of cell types, are compensatory and the patient is asymptomatic. However, with disease progression, the attempt to reverse or delay cardiac dysfunction is deleterious, leading to multi-organ congestion, fibrosis and decompensation and finally symptomatic HF. In conclusion, these neurohormonal pathways mediate the evolution of HF and have become a way to monitor HF. Specifically, these mediators have become important in the diagnosis and prognosis of this highly fatal cardiovascular disease. Finally, while these multiple neurohumoral factors serve as important HF biomarkers, they can also be targeted for more effective and curative HF treatments.

Displacement of cortisol from human heart by acute administration of a mineralocorticoid receptor antagonist

CONTEXT

Mineralocorticoid receptor (MR) antagonists have beneficial effects in patients with heart failure and myocardial infarction, often attributed to blocking aldosterone action in the myocardium. However, binding of aldosterone to MR requires local activity of the enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), which inactivates cortisol to cortisone and thereby prevents receptor occupancy by cortisol. In vivo activity of 11β-HSD2 and potential occupancy of MR by cortisol in human heart have not been quantified.

OBJECTIVE

This study aimed to measure in vivo activity of 11β-HSD2 and to establish whether cortisol binds MR in human heart.

PARTICIPANTS AND INTERVENTIONS

Nine patients without heart failure undergoing diagnostic coronary angiography were infused to steady state with the stable isotope tracers 9,11,12,12-[(2)H]4-cortisol and 1,2-[(2)H]2-cortisone to quantify cortisol and cortisone production. Samples were obtained from the femoral artery and coronary sinus before and for 40 minutes after bolus iv administration of an MR antagonist, potassium canrenoate. Coronary sinus blood flow was measured by venography and Doppler flow wire.

RESULTS

There was no detectable production of cortisol or cortisone across the myocardium. After potassium canrenoate administration, plasma aldosterone concentrations increased substantially but aldosterone was not detectably released from the myocardium. In contrast, plasma cortisol concentrations did not change in the systemic circulation but tissue-bound cortisol was released transiently from the myocardium after potassium canrenoate administration.

CONCLUSIONS

Human cardiac 11β-HSD2 activity appears too low to inactivate cortisol to cortisone. Cortisol is displaced acutely from the myocardium by MR antagonists and may contribute to adverse MR activation in human heart.

Mineralocorticoid receptors in vascular disease: connecting molecular pathways to clinical implications

The mineralocorticoid receptor (MR), a steroid-hormone-activated transcription factor, plays a substantial role in cardiovascular diseases. MR antagonists (MRAs) have long been appreciated as effective treatments for heart failure and hypertension; however, recent research suggests that additional patient populations may also benefit from MRA therapy. Experimental evidence demonstrates that in addition to its classic role in the regulating sodium handling in the kidney, functional MR is expressed in the blood vessels and contributes to hypertension, vascular inflammation and remodeling, and atherogenesis. MR activation drives pathological phenotypes in smooth muscle cells, endothelial cells, and inflammatory cells, whereas MRAs inhibit these effects. Collectively, these studies demonstrate a new role for extrarenal MR in cardiovascular disease. This review summarizes these new lines of evidence and how they contribute to the mechanisms of atherosclerosis, pulmonary and systemic hypertension, and vein graft failure, and describes new patient populations that may benefit from MRA therapy.

The past, present and future of renin-angiotensin aldosterone system inhibition

The renin-angiotensin aldosterone system (RAAS) is central to the pathogenesis of cardiovascular disease. RAAS inhibition can reduce blood pressure, prevent target organ damage in hypertension and diabetes, and improve outcomes in patients with heart failure and/or myocardial infarction. This review presents the history of RAAS inhibition including a summary of key heart failure, myocardial infarction, hypertension and atrial fibrillation trials. Recent developments in RAAS inhibition are discussed including implementation and optimization of current drug therapies. Finally, ongoing clinical trials, opportunities for future trials and issues related to the barriers and approvability of novel RAAS inhibitors are highlighted.

Extracellular matrix turnover biomarkers predict long-term left ventricular remodeling after myocardial infarction: insights from the REVE-2 study

BACKGROUND

Extracellular matrix turnover plays a key role in wound repair after myocardial infarction (MI). The aim of the study was to evaluate whether biomarkers of myocardial fibrosis measurements 1 month after MI may predict left ventricular (LV) remodeling.

METHODS AND RESULTS

This prospective multicenter study included 246 patients with a first anterior Q-wave MI. Echocardiographic studies were performed at hospital discharge and 12 months after MI. Brain natriuretic peptide as well as biomarkers of myocardial fibrosis (type 1 collagen telopeptide, aminoterminal propeptide of type I procollagen, aminoterminal propeptide of type III procollagen) were measured 1 month after MI in 218 patients. In multivariate analysis, aminoterminal propeptide of type III procollagen/type 1 collagen telopeptide ratio ≤1 (odds ratio [95% confidence interval], 1.86 [1.02-3.39]; P=0.043) 1 month after MI and brain natriuretic peptide >100 pg/mL (2.35 [1.28-4.31]; P=0.006) were associated with a pejorative LV remodeling, whereas LV ejection fraction at discharge (per 5% increment; 0.78 [0.65-0.94]; P=0.01) was independently associated with lower rates of detrimental LV remodeling at 12 months. Patients with high brain natriuretic peptide and aminoterminal propeptide of type III procollagen/type 1 collagen telopeptide ratio ≤1, measured 1 month after MI, had the highest risk of developing a primary composite event (cardiovascular death or hospitalization for worsening heart failure; 14 events per 216 patients; P=0.0001) during a 3-year follow-up.

CONCLUSIONS

Myocardial fibrosis turnover after MI is associated with LV remodeling. Low aminoterminal propeptide of type III procollagen/type 1 collagen telopeptide ratio (≤1) at 1 month is predictive, in addition to brain natriuretic peptide and LV ejection fraction, of detrimental LV remodeling as well as cardiovascular deaths and hospitalizations for heart failure.

Aldosterone receptor antagonists: current perspectives and therapies

Aldosterone is a downstream effector of angiotensin II in the renin-angiotensin-aldosterone system and binds to the mineralocorticoid receptor. The classical view of aldosterone primarily acting at the level of the kidneys to regulate plasma potassium and intravascular volume status is being supplemented by evidence of new "off-target" effects of aldosterone in other organ systems. The genomic effects of aldosterone are well known, but there is also evidence for non-genomic effects and these recently identified effects of aldosterone have required a revision in the traditional view of aldosterone's role in human health and disease. The aim of this article is to review the biological action of aldosterone and the mineralocorticoid receptor leading to subsequent physiologic and pathophysiologic effects involving the vasculature, central nervous system, heart, and kidneys. Furthermore, we outline current evidence evaluating the use of mineralocorticoid receptor antagonists in the treatment of primary aldosteronism, primary hypertension, resistant hypertension, obstructive sleep apnea, heart failure, and chronic kidney disease.

Inhibition of the Renin-Angiotensin System Reduces the Rise in Serum Aldosterone in Acute Coronary Syndrome Patients with Preserved Left Ventricular Function: Observations from the AVANT GARDE-TIMI 43 Trial

BACKGROUND

Acute coronary syndrome (ACS) activates neurohormonal pathways, including elevations in circulating aldosterone, with deleterious cardiovascular effects. We aimed to determine if early, more complete renin-angiotensin-aldosterone system inhibition (RAASI) in post-ACS patients without ventricular dysfunction or heart failure would result in a graded reduction in aldosterone concentrations.

METHODS

We performed serial measurement of serum aldosterone within the Aliskiren and Valsartan to Reduce NT-proBNP via Renin-Angiotensin-Aldosterone-System Blockade (AVANT GARDE)–Thrombolysis in Myocardial Infarction (TIMI) 43 trial, a randomized double-blind, placebo controlled trial of RAASI by valsartan, aliskiren, or both in post-ACS patients with preserved ventricular function but increased natriuretic peptides. Aldosterone was measured at randomization and week 8.

RESULTS

Median aldosterone concentrations were comparable across treatment arms at baseline (9.26 ng/dL; interquartile range 7.12–12.76; n = 1073). In the placebo group, there was a significant increase in aldosterone over 8 weeks (19.7% rise, 2.20 (0.36) ng/dL, P &lt; 0.0001) that was significantly reduced across active RAASI therapies (1.36 (0.39) ng/dL with aliskiren; 1.02 (0.37) ng/dL with valsartan; and 0.85 (0.37) ng/dL with combination therapy, P trend = 0.008). Compared to placebo, RAASI monotherapy resulted in a pooled relative absolute aldosterone change of −1.01 (0.45) ng/dL (P = 0.026 vs placebo), and combination therapy resulted in a relative absolute aldosterone change of −1.35 (0.52) ng/dL (P = 0.01 vs placebo). No significant difference in aldosterone concentrations was achieved between dual vs single RAASI (P = 0.47).

CONCLUSIONS

In ACS patients with preserved ventricular function but increased natriuretic peptides, serum aldosterone rises over time and is blunted by more complete RAASI. The clinical implications and role for RAASI in this population warrant further investigation.

The ubiquitous mineralocorticoid receptor: clinical implications

Mineralocorticoid receptors (MR) exist in many tissues, in which they mediate diverse functions crucial to normal physiology, including tissue repair and electrolyte and fluid homeostasis. However, inappropriate activation of MR within these tissues, and especially in the brain, causes hypertension and pathological vascular, cardiac, and renal remodeling. MR binds aldosterone, cortisol and corticosterone with equal affinity. In aldosterone-target cells, co-expression with the 11β-hydroxysteroid dehydrogenase 2 (HSD2) allows aldosterone specifically to activate MR. Aldosterone levels are excessive in primary aldosteronism, but in conditions with increased oxidative stress, like CHF, obesity and diabetes, MR may also be inappropriately activated by glucocorticoids. Unlike thiazide diuretics, MR antagonists are diuretics that do not cause insulin resistance. Addition of MR antagonists to standard treatment for hypertension and cardiac or renal disease decreases end-organ pathology and sympathetic nerve activation (SNA), and increases quality of life indices.

Targeting the renin-angiotensin-aldosterone system in heart failure

The renin-angiotensin-aldosterone system is a well-established therapeutic target in the treatment of heart failure (HF). Substantial advances have been made with existing agents--angiotensin-converting enzyme (ACE) inhibitors, angiotensin II-receptor blockers (ARBs), and mineralocorticoid-receptor antagonists (MRAs)--and new data continue to emerge. The indication for the use of MRAs has been broadened to include potentially all patients who have HF with reduced ejection fraction (HFrEF), and ACE inhibitors might have a novel application in patients who are at risk of left ventricular dysfunction (those with aortic valvular disease or pacing-induced heart disease). ARBs have been shown to be a beneficial alternative to ACE inhibitors in HFrEF, but their value when added to ACE inhibitors has been questioned. Upstream, direct renin blockade with aliskiren is being pursued in two large trials of HF, despite the premature halting of a third study. A substantial, unmet need remains in patients who have HF with preserved ejection fraction (HFpEF). New data on spironolactone and LCZ696 (a combined ARB and neprilysin inhibitor) show promise for these patients. Results of the TOPCAT study of spironolactone in patients with HFpEF are awaited, and LCZ696 is now being tested in a large trial in patients with HFrEF.

Aldosterone and cardiovascular disease: the heart of the matter

Aldosterone contributes to the endocrine basis of heart failure, and studies on cardiac aldosterone signaling have reinforced its value as a therapeutic target. Recent focus has shifted to new roles of aldosterone that appear to depend on coexisting pathologic stimuli, cell type, and disease etiology. This review evaluates recent advances in mechanisms underlying aldosterone-induced cardiac disease and highlights the interplay between aldosterone and Ca(2+)/calmodulin dependent protein kinase II, whose hyperactivity during heart failure contributes to disease progression. Increasing evidence implicates aldosterone in diastolic dysfunction, and there is a need to develop more targeted therapeutics such as aldosterone synthase inhibitors and molecularly specific antioxidants. Despite accumulating knowledge, many questions still persist and will likely dictate areas of future research.

Mineralocorticoid receptor activation in myocardial infarction and failure: recent advances

The classical view of aldosterone actions via the mineralocorticoid receptor (MR) limited to control of fluid balance and blood pressure homoeostasis has been progressively overcome by clinical and experimental evidence emphasizing the pleiotropic role of MR activation in the pathogenesis of cardiovascular disease. Clinical studies have shown the benefit of MR blockade in patients with left ventricular dysfunction and heart failure after myocardial infarction (MI), hypertension or diabetic nephropathy. Deleterious effects of MR activation include cardiac structural and electrical remodelling, cardiovascular fibrosis, inflammation and oxidative stress. Complexity of pathophysiological role of MR derives from the presence of circulating glucocorticoids at higher concentrations than aldosterone and the equal affinity of the MR for aldosterone, cortisol and corticosterone. Recent experimental studies using different animal models and genetic tools have deeply explored the cell-specific functional role of MR in cardiovascular pathology. This review addresses emerging preclinical studies as well as ongoing clinical trials regarding MR activation in MI and failure.

Mineralocorticoid receptor antagonists for heart failure with reduced ejection fraction: integrating evidence into clinical practice

Mineralocorticoid receptor antagonists (MRAs) improve survival and reduce morbidity in patients with heart failure, reduced ejection fraction (HF-REF), and mild-to-severe symptoms, and in patients with left ventricular systolic dysfunction and heart failure after acute myocardial infarction. These clinical benefits are observed in addition to those of angiotensin converting enzyme inhibitors or angiotensin receptor blockers and beta-blockers. The morbidity and mortality benefits of MRAs may be mediated by several proposed actions, including antifibrotic mechanisms that slow heart failure progression, prevent or reverse cardiac remodelling, or reduce arrhythmogenesis. Both eplerenone and spironolactone have demonstrated survival benefits in individual clinical trials. Pharmacologic differences exist between the drugs, which may be relevant for therapeutic decision making in individual patients. Although serious hyperkalaemia events were reported in the major MRA clinical trials, these risks can be mitigated through appropriate patient selection, dose selection, patient education, monitoring, and follow-up. When used appropriately, MRAs significantly improve outcomes across the spectrum of patients with HF-REF.

Aldosterone receptor antagonists in cardiovascular disease: a review of the recent literature and insight into potential future indications

Randomized controlled trials demonstrate the efficacy of aldosterone receptor antagonists (spironolactone and eplerenone) as a useful pharmacologic intervention specifically in patients with New York Heart Association (NYHA) class III and IV heart failure, in patients with an ejection fraction <40% after myocardial infarction, and most recently in patients with mildly symptomatic heart failure. However, aldosterone receptor antagonists may be beneficial in a broader patient population. Aldosterone receptor antagonists can potentially serve as an antiarrhythmic pharmacologic agent for atrial and ventricular arrhythmias, an anti-ischemic medication in coronary artery disease through prevention of myocardial fibrosis and vascular damage, and as an agent in people with asymptomatic and mild heart failure (NYHA classes I and II) and diastolic heart failure. However, many clinicians remain reluctant to prescribe this highly efficacious pharmacologic therapy for a variety of reasons, including concerns about polypharmacy and hyperkalemia. Recent observational analysis demonstrates that less than one-third of eligible patients hospitalized with heart failure actually received aldosterone antagonist therapy. This article will review the current and potential future uses of aldosterone receptor antagonists across the entire spectrum of cardiovascular disease. The authors have no funding, financial relationships, or conflicts of interest to disclose.

Aldosterone, mineralocorticoid receptor, and heart failure

Several large clinical studies have demonstrated the important benefit of mineralocorticoid receptor (MR) antagonists in patients with heart failure, left ventricular dysfunction after myocardial infarction, hypertension or diabetic nephropathy. Aldosterone adjusts the hydro-mineral balance in the body, and thus participates decisively to the control of blood pressure. This traditional view of the action of aldosterone restricted to sodium reabsorption in epithelial tissues must be revisited. Clinical and experimental studies indicated that chronic activation of the MR in target tissues induces structural and functional changes in the heart, kidneys and blood vessels. These deleterious effects include cardiac and renal fibrosis, inflammation and vascular remodeling. It is important to underscore that these effects are due to elevated MR activation that is inadequate for the body salt requirements. Aldosterone is generally considered as the main ligand of MR. However, this is a matter of debate especially in heart. Complexity arises from the glucocorticoids with circulating concentrations much higher than those of aldosterone, and the fact that the MR has a high affinity for 11β-hydroxyglucocorticoids. Nevertheless, the beneficial effects of MR inhibition in patients with heart failure emphasize the importance of this receptor in cardiovascular tissue. Diverse experimental models and strains of transgenic mice have allowed to dissect the effects of aldosterone and the MR in the heart. Taken together experimental and clinical data clearly highlight the deleterious cardiovascular effects of MR stimulation.

Oxidation of CaMKII determines the cardiotoxic effects of aldosterone

Excessive activation of the β-adrenergic, angiotensin II (Ang II) and aldosterone signaling pathways promotes mortality after myocardial infarction, and antagonists targeting these pathways are core therapies for treating this condition. Catecholamines and Ang II activate the multifunctional Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), the inhibition of which prevents isoproterenol-mediated and Ang II-mediated cardiomyopathy. Here we show that aldosterone exerts direct toxic actions on myocardium by oxidative activation of CaMKII, causing cardiac rupture and increased mortality in mice after myocardial infarction. Aldosterone induces CaMKII oxidation by recruiting NADPH oxidase, and this oxidized and activated CaMKII promotes matrix metalloproteinase 9 (MMP9) expression in cardiomyocytes. Myocardial CaMKII inhibition, overexpression of methionine sulfoxide reductase A (an enzyme that reduces oxidized CaMKII) or NADPH oxidase deficiency prevented aldosterone-enhanced cardiac rupture after myocardial infarction. These findings show that oxidized myocardial CaMKII mediates the cardiotoxic effects of aldosterone on the cardiac matrix and establish CaMKII as a nodal signal for the neurohumoral pathways associated with poor outcomes after myocardial infarction.

Targeting the aldosterone pathway in cardiovascular disease

Accumulated evidence has demonstrated that aldosterone is a key player in the pathogenesis of cardiovascular (CV) disease. Multiple clinical trials have documented that intervention in the aldosterone pathway can reduce blood pressure and lower albuminuria and improve outcome in patients with heart failure or myocardial infarction. Recent studies have unraveled details about the role of aldosterone at the cellular level in CV disease. The relative importance of glucocorticoids and aldosterone in terms of mineralocorticoid receptor activation is currently being debated. Also, studies are addressing which aldosterone modulator to use, which timing of treatment to aim for, and in which population to intervene. This review provides an overview of recent developments in the understanding of the role of aldosterone in CV disease, with particular reference to mechanisms and potential targets of intervention. Finally, ongoing or desirable clinical trials in the field are highlighted. The review is partly based on discussions between basic scientists and clinical trialists at the Cardiovascular Clinical Trials Forum 2009 and subsequently updated to encompass the most recent developments.