eplerenone and Myocarditis

Cardiomyopathy is a leading cause of death for Duchenne muscular dystrophy. Here, we find that the mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) can share common ligands but play distinct roles in dystrophic heart and skeletal muscle pathophysiology. Comparisons of their ligand structures indicate that the Δ9,11 modification of the first-in-class drug vamorolone enables it to avoid interaction with a conserved receptor residue (N770/N564), which would otherwise activate transcription factor properties of both receptors. Reporter assays show that vamorolone and eplerenone are MR antagonists, whereas prednisolone is an MR agonist. Macrophages, cardiomyocytes, and CRISPR knockout myoblasts show vamorolone is also a dissociative GR ligand that inhibits inflammation with improved safety over prednisone and GR-specific deflazacort. In mice, hyperaldosteronism activates MR-driven hypertension and kidney phenotypes. We find that genetic dystrophin loss provides a second hit for MR-mediated cardiomyopathy in Duchenne muscular dystrophy model mice, as aldosterone worsens fibrosis, mass and dysfunction phenotypes. Vamorolone successfully prevents MR-activated phenotypes, whereas prednisolone activates negative MR and GR effects. In conclusion, vamorolone targets dual nuclear receptors to treat inflammation and cardiomyopathy with improved safety.

Topics: Aldosterone; Animals; Anti-Inflammatory Agents; Cardiomyopathies; Computer Simulation; CRISPR-Associated Protein 9; Disease Models, Animal; Eplerenone; Gene Knockout Techniques; Hydrogen Bonding; Macrophages; Mice; Mice, Inbred C57BL; Mineralocorticoid Receptor Antagonists; Muscular Dystrophy, Duchenne; Myocarditis; Myocytes, Cardiac; Prednisolone; Pregnadienediols; RAW 264.7 Cells; Receptors, Glucocorticoid; Receptors, Mineralocorticoid

 Hypertensive patients with large blood pressure variability (BPV) have aggravated target organ damage. Because the aldosterone/mineralocorticoid receptor (MR) system is a possible mechanism of hypertensive organ damage, we investigated in spontaneously hypertensive rats (SHRs) whether a specific MR blocker, eplerenone, would prevent BPV-induced aggravation of hypertensive cardiac remodeling..  A rat model of a combination of hypertension and large BPV was created by performing bilateral sinoaortic denervation (SAD) in SHRs. SAD increased BPV without changing mean BP. SAD induced perivascular macrophage infiltration and aggravated myocardial fibrosis and cardiac hypertrophy, resulting in LV systolic dysfunction. Immunohistostaining revealed SAD-induced translocation of MRs into the nuclei (ie, MR activation) of the intramyocardial arterial medial cells and cardiac myocytes. SAD increased phosphorylation of p21-activated kinase1 (PAK1), a regulator of MR nuclear translocation. Chronic administration of a subdepressor dose of eplerenone prevented MR translocation, macrophage infiltration, myocardial fibrosis, cardiac hypertrophy, and LV dysfunction, while not affecting BPV. Circulating levels of aldosterone and cortisol were not changed by SAD..  Eplerenone inhibited the aggravation of cardiac inflammation and hypertensive cardiac remodeling, and thereby prevented progression of LV dysfunction in SHRs with large BPV. This suggests that the PAK1-MR pathway plays a role in cardiac inflammation and remodeling induced by large BPV superimposed on hypertension, independent of circulating aldosterone. 

Topics: Active Transport, Cell Nucleus; Aldosterone; Animals; Blood Pressure; Cardiomegaly; Cell Nucleus; Eplerenone; Humans; Hydrocortisone; Hypertension; Macrophages; Mineralocorticoid Receptor Antagonists; Muscle Proteins; Myocarditis; Myocardium; p21-Activated Kinases; Phosphorylation; Rats; Rats, Inbred SHR; Receptors, Mineralocorticoid; Spironolactone; Ventricular Remodeling

Inflammation contributes to increased cardiovascular morbidity and mortality associated with activation of the renin-angiotensin-aldosterone system. The aim of this study was to investigate whether eplerenone, a selective aldosterone receptor antagonist, has anti-inflammatory effects on viral myocarditis.. Four-week-old inbred male DBA/2 mice were inoculated intraperitoneally with 10 plaque-forming units (pfu) of the encephalomyocarditis (EMC) virus. Mice were fed with standard chow (control) or with chow containing 2.5 mg/kg of eplerenone, starting either on day 0 (inoculation) or day 7. Survival at 28 days was significantly higher in the mice which started eplerenone treatment on day 0 (35 vs. 15% in controls, each n = 40, P < 0.05). The area of myocardial fibrosis on day 28 was significantly smaller in the eplerenone-treated mice than in controls (19.8 +/- 2.6%, n = 14, vs. 33.4 +/- 5.4%, n = 6, mean +/- SEM, P < 0.05). Gene expression of mouse mast cell proteases-4 and -5, matrix metalloproteinase-9, and type I procollagen on day 6 after EMC virus inoculation was significantly decreased in the hearts of eplerenone-treated mice.. These results suggest that eplerenone has anti-inflammatory effects, and exerts its beneficial effects on viral myocarditis by suppression of genes related to mast cells and cardiac remodelling in the hearts of mice.

Topics: Animals; Cardiovirus Infections; Disease Models, Animal; DNA, Viral; Encephalomyocarditis virus; Eplerenone; Male; Mice; Mice, Inbred DBA; Mineralocorticoid Receptor Antagonists; Myocarditis; Myocardium; Polymerase Chain Reaction; Spironolactone; Treatment Outcome

Mineralocorticoid receptor (MR) blockade reduces morbidity and mortality after acute myocardial infarction; however, the underlying mechanisms are still under investigation. This study examined whether MR antagonism promotes healing of the infarcted myocardium. Starting immediately after coronary ligation, male Wistar rats were treated with the selective MR antagonist eplerenone (100 mg/kg per day by gavage) or placebo for 2 to 7 days. At 7 days, eplerenone therapy versus placebo significantly reduced thinning and dilatation of the infarcted wall, improved left ventricular function, and enhanced neovessel formation in the injured myocardium. At 2 days, eplerenone-treated rats displayed lower plasma corticosterone levels, higher circulating blood monocytes, and more macrophages infiltrating the infarcted myocardium. MR blockade led to a transient upregulation (at days 2 and 3 but not at day 7) of monocyte chemoattractant protein-1, tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, interleukin-10, and interleukin-4 and an increase in factor XIIIa protein expression in the healing myocardium. Prevention of macrophage accumulation into the infarct zone by treatment with liposome-encapsulated clodronate almost abrogated the protein expression of factor XIIIa and the beneficial effects of eplerenone on infarct expansion. In conclusion, selective MR blockade immediately after myocardial infarction accelerated macrophage infiltration and transiently increased the expression of healing promoting cytokines and factor XIIIa in the injured myocardium resulting in enhanced infarct neovascularization and reduced early LV dilation and dysfunction.

Topics: Aldosterone; Animals; Clodronic Acid; Collagen; Cytokines; Eplerenone; Factor XIIIa; Heart Failure; Humans; Male; Mineralocorticoid Receptor Antagonists; Monocytes; Myocardial Infarction; Myocarditis; Myocardium; Neovascularization, Physiologic; Rats; Rats, Wistar; RNA, Messenger; Spironolactone; Ventricular Function, Left; Wound Healing

Aldosterone blockade reduces morbidity and mortality in patients with heart failure. We studied the effects of eplerenone, a novel aldosterone blocker, on the progression of left ventricular dysfunction and remodeling in rats with dilated cardiomyopathy after autoimmune myocarditis. Twenty-eight days after immunization, the surviving Lewis rats were randomized to 1 month's oral treatment with low-dose eplerenone (group L), high-dose eplerenone (group H) or vehicle (group V). Five of 15 (33%) rats in group V and 3 of 15 (20%) rats in group L died during the course of treatment. High-dose eplerenone significantly reduced cardiomyocyte hypertrophy, heart weight and heart weight to body weight ratio. Eplerenone improved left ventricular function in a dose-dependent manner. Central venous pressure and left ventricular end-diastolic pressure were lower, and +/-dP/dt and fractional shortening were higher in group H than group V. Eplerenone also attenuated myocardial fibrosis and reduced left ventricular mRNA expressions of TGF-beta(1) and collagen-III. Our results indicate that treatment with eplerenone improved left ventricular dysfunction and attenuated left ventricular remodeling in rats with heart failure.

Topics: Animals; Autoimmune Diseases; Cardiomyopathy, Dilated; Collagen Type III; Dose-Response Relationship, Drug; Electrocardiography; Eplerenone; Fibrosis; Hemodynamics; Male; Mineralocorticoid Receptor Antagonists; Myocarditis; Myocardium; Rats; Rats, Inbred Lew; RNA, Messenger; Spironolactone; Transforming Growth Factor beta; Ventricular Dysfunction, Left; Ventricular Remodeling

Although aldosterone, acting via mineralocorticoid receptors, causes left ventricular (LV) hypertrophy in experimental models of high-aldosterone hypertension, little is known about the role of aldosterone or mineralocorticoid receptors in mediating adverse remodeling in response to chronic pressure overload.. We used the mineralocorticoid receptor-selective antagonist eplerenone (EPL) to test the role of mineralocorticoid receptors in mediating the transition from hypertrophy to failure in mice with chronic pressure overload caused by ascending aortic constriction (AAC). One week after AAC, mice were randomized to regular chow or chow containing EPL (200 mg/kg per day) for an additional 7 weeks. EPL had no significant effect on systolic blood pressure after AAC. Eight weeks after AAC, EPL treatment improved survival (94% versus 65%), attenuated the increases in LV end-diastolic (3.4+/-0.1 versus 3.7+/-0.1 mm) and end-systolic (2.0+/-0.1 versus 2.5+/-0.2 mm) dimensions, and ameliorated the decrease in fractional shortening (42+/-2% versus 34+/-4%). EPL also decreased myocardial fibrosis, myocyte apoptosis, and the ratio of matrix metalloproteinase-2/tissue inhibitor of matrix metalloproteinase-2. These beneficial effects of EPL were associated with less myocardial oxidative stress, as assessed by 3-nitrotyrosine staining, reduced expression of the adhesion molecule intercellular adhesion molecule-1, and reduced infiltration by macrophages.. Mineralocorticoid receptors play an important role in mediating the transition from LV hypertrophy to failure with chronic pressure overload. The effects of mineralocorticoid receptor stimulation are associated with alterations in the interstitial matrix and myocyte apoptosis and may be mediated, at least in part, by oxidative stress and inflammation.

Topics: Animals; Aorta; Apoptosis; Blood Pressure; Cell Size; Chronic Disease; Constriction, Pathologic; Drug Evaluation, Preclinical; Eplerenone; Fibrosis; Heart Failure; Hypertrophy, Left Ventricular; Intercellular Adhesion Molecule-1; Ligation; Male; Matrix Metalloproteinases; Mice; Mineralocorticoid Receptor Antagonists; Myocarditis; Myocardium; Myocytes, Cardiac; Oxidative Stress; Pressure; Random Allocation; Receptors, Mineralocorticoid; Spironolactone; Tissue Inhibitor of Metalloproteinase-1; Tissue Inhibitor of Metalloproteinase-2; Tyrosine