Molecular mechanisms of mineralocorticoid receptor antagonism by eplerenone.

Mineralocorticoid receptor (MR) antagonism has proven to effectively attenuate the pathophysiological effects of aldosterone in clinical and experimental settings of hypertension and heart failure. MR activates transcription of target genes upon aldosterone binding, and eplerenone selectively binds to MR and blocks aldosterone- mediated activation. In this review, we summarize the preclinical and clinical evidence supporting the beneficial effects of eplerenone (INSPRA), a selective aldosterone blocker, in the treatment of hypertension and heart failure.

Emerging therapies for heart failure.

Although multiple advancements have been made in the treatment of heart failure (HF), mortality rates remain alarmingly high. The accepted arsenal of therapeutics includes a diuretic, digitalis, a beta-blocking agent and an inhibitor of the renin-angiotensin-aldosterone system. Despite the employment of a vast array of agents, nearly 300,000 patients in the US die annually with HF as a primary or contributory cause of death.

Aldosterone target organ protection by eplerenone.

The classical mineralocorticoid effect of aldosterone on unidirectional transepithelial sodium transport in the kidney was long thought to be the predominant effect of this hormone. However, there is convincing evidence for additional extrarenal actions of aldosterone that are mediated via activation of mineralocorticoid receptors (MRs) in the heart, vasculature and brain. It is now postulated that many of the detrimental effects of aldosterone are mediated through MR activation in these nonclassical target organs.

The evolution of aldosterone antagonists.

Since the isolation and purification of aldosterone from adrenal extracts 50 years ago (Experientia 9 (1953) 33), scientists have learned a great deal about how and where aldosterone acts, the factors that control its release, what is its role in the pathophysiology of cardiovascular disease, how to make and study aldosterone antagonists, and for what medical purposes these agents are useful. In this paper, we will discuss the evolution of aldosterone antagonists from the relatively nonselective spironolactone (Aldactone), to the highly selective eplerenone (Inspra). Eplerenone represents a molecule with improved steroid receptor selectivity and pharmacokinetic properties in man compared to spironolactone.

Transgenic model of aldosterone-driven cardiac hypertrophy and heart failure.

Aldosterone classically promotes unidirectional transepithelial sodium transport, thereby regulating blood volume and blood pressure. Recently, both clinical and experimental studies have suggested additional, direct roles for aldosterone in the cardiovascular system. To evaluate aldosterone activation of cardiomyocyte mineralocorticoid receptors, transgenic mice overexpressing 11beta-hydroxysteroid dehydrogenase type 2 in cardiomyocytes were generated using the mouse alpha-myosin heavy chain promoter.

Eplerenone, a new selective aldosterone blocker.

Activation of the renin-angiotensin-aldosterone system is associated with unsatisfactory outcomes in patients with hypertension and heart failure in that activation of this system is correlated strongly with both the incidence and extent of end-organ damage. Despite the availability of the angiotensin converting enzyme inhibitors (ACEi) and the angiotensin receptor blockers (ARB), unblocked aldosterone levels remain an important risk factor for cardiovascular disease progression. New preclinical data generated over the last few years strongly supports the hypothesis that aldosterone has important deleterious effects on the cardiovascular system independent of the classical action of this hormone on renal epithelial cells.

Aldosterone/salt induces renal inflammation and fibrosis in hypertensive rats.

Background: We evaluated the role of aldosterone as a mediator of renal inflammation and fibrosis in a rat model of aldosterone/salt hypertension using the selective aldosterone blocker, eplerenone.

Methods: Unnephrectomized, Sprague-Dawley rats were given 1% NaCl (salt) to drink and randomized to receive treatment for 28 days: vehicle infusion (control); 0.75 microg/hour aldosterone subcutaneous infusion; or aldosterone infusion + 100 mg/kg/day oral dose of eplerenone.

Effects of long-term monotherapy with eplerenone, a novel aldosterone blocker, on progression of left ventricular dysfunction and remodeling in dogs with heart failure.

Background: In heart failure (HF), aldosterone has been implicated in the formation of reactive interstitial fibrosis, a maladaptation that contributes to left ventricular (LV) remodeling. Eplerenone is a novel selective aldosterone blocker. The present study examined the effects of long-term monotherapy with eplerenone on the progression of LV dysfunction and remodeling in dogs with chronic HF.

Aldosterone induces a vascular inflammatory phenotype in the rat heart.

Vascular inflammation was examined as a potential mechanism of aldosterone-mediated myocardial injury in uninephrectomized rats receiving 1% NaCl-0.3% KCl to drink for 1, 2, or 4 wk and 1) vehicle, 2) aldosterone infusion (0.75 microg/h), or 3) aldosterone infusion (0.

Structural, functional, and molecular characterization of the SHHF model of heart failure.

Heart failure is a complex multifactorial disease resulting in a myriad of progressive changes at the molecular, cellular, and physiological level. To better understand the mechanisms associated with the development of congestive heart failure, a comprehensive examination of the aging lean male spontaneously hypertensive, heart failure-prone rat (SHHF) was conducted. Myocardial function and structural integrity progressively diminished as evidenced by decreased ejection fraction and increased left ventricular volume measured using echocardiography.