eplerenone and Disease-Models--Animal

Mineralocorticoid receptors (MRs) are expressed in non-epithelial tissues, such as blood vessels, the heart and adipose tissue. The combined effects of aldosterone and insulin link the metabolic syndrome with hypertension and salt sensitivity. Eplerenone is the newly developed inhibitor of MRs that has significantly fewer adverse effects than similar doses of spironolactone. Eplerenone has been reported to have anti-hypertensive and protective effects on cardiovascular and renal injury in salt-sensitive hypertensive animal models, such as the Dahl salt-sensitive (DS) hypertensive rat and leptin receptor-deficient spontaneously hypertensive rat (SHR/cp). Eplerenone also increases nitric oxide bioavailability and improves impaired endothelial function by decreasing oxidative stress. Clinical studies support the concept that eplerenone is effective for the treatment of salt-sensitive hypertension as well as idiopathic hyperaldosteronism and does not have adverse anti-androgenic adverse effects. In Japan, eplerenone has been used clinically since 2007 for the treatment of hypertension, with its price being marginally lower than all types of angiotensin II receptor antagonists. This will inevitably result in an increasing number of hypertensive patients and those with primary aldosteronism being treated with this agent in the near future.

Topics: Aldosterone; Animals; Disease Models, Animal; Eplerenone; Humans; Hypertension; Mineralocorticoid Receptor Antagonists; Rats; Rats, Inbred Dahl; Sodium Chloride; Spironolactone

Increasing recognition of the role of aldosterone in cardiovascular disease has been supported by a significant body of evidence from animal models. This evidence has been translated into clinical practice, and large-scale, randomized, placebo-controlled trials have confirmed the beneficial effects of mineralocorticoid blockade in patients with heart failure. As a consequence, there has been a resurgence in the use of mineralocorticoid-receptor antagonists in clinical practice that has prompted the search for a potent and specific antagonist without the sexual side effects of spironolactone. Eplerenone, a mineralocorticoid-receptor antagonist with minimal binding to the progesterone and androgen receptors, is now licensed for treatment of heart failure in Europe and heart failure and hypertension in the US; it has also been proposed as a treatment for a variety of cardiovascular conditions. This article reviews the current concepts of the actions of aldosterone at a cellular level. Recent findings regarding its role as a cardiovascular hormone, both in animal models and human studies, are discussed. We also describe the development of mineralocorticoid-receptor blockers following the isolation of aldosterone and discuss the subsequent search for a specific mineralocorticoid antagonist. In addition we detail the effects of eplerenone in a number of clinical situations and outline its potential future applications.

Topics: Animals; Cardiovascular Diseases; Disease Models, Animal; Eplerenone; Heart Failure; Humans; Hypertension; Mineralocorticoid Receptor Antagonists; Spironolactone

Topics: Aldosterone; Animals; Body Water; Disease Models, Animal; Eplerenone; Humans; Hypertension; Kidney Diseases; Mineralocorticoid Receptor Antagonists; Potassium; Proteinuria; Receptors, Mineralocorticoid; Sodium; Spironolactone

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. The new selective aldosterone blocker, eplerenone, has been shown to produce significant cardioprotective and renoprotecive effects in experimental models of cardiovascular disease. Early clinical studies suggests that eplerenone may have important therapeutic benefit in the treatment of hypertension and heart failure post-myocardial infarction (post-MI).

Topics: Aldosterone; Angiotensin-Converting Enzyme Inhibitors; Animals; Cardiovascular System; Disease Models, Animal; Dogs; Eplerenone; Heart Injuries; Humans; Kidney Diseases; Mineralocorticoid Receptor Antagonists; Rats; Renin-Angiotensin System; Spironolactone

Data from animal studies and clinical trials indicate that aldosterone causes cardiovascular and renal injury through mineralocorticoid receptor-dependent mechanisms. However, although aldosterone receptor antagonism reduces mortality in patients with congestive heart failure, the progestational and antiandrogenic side effects of the nonspecific aldosterone receptor antagonist, spironolactone, have limited its usefulness in the treatment of hypertension. This review provides an overview of the pharmacology, efficacy, and safety of a new, more selective aldosterone receptor antagonist, eplerenone, in the context of emerging concepts of the role of aldosterone in cardiovascular toxicity.

Topics: Aldosterone; Animals; Cardiovascular Diseases; Cardiovascular System; Disease Models, Animal; Eplerenone; Humans; Hypertension; Mineralocorticoid Receptor Antagonists; Renin-Angiotensin System; Spironolactone; Treatment Outcome

Aldosterone synthase inhibition provides the potential to attenuate both the mineralocorticoid receptor-dependent and independent actions of aldosterone. In vitro studies with recombinant human enzymes showed LCI699 to be a potent, reversible, competitive inhibitor of aldosterone synthase (K i = 1.4 ± 0.2 nmol/L in humans) with relative selectivity over 11β-hydroxylase.. Hormonal effects of orally administered LCI699 were examined in rat and monkey in vivo models of adrenocorticotropic hormone (ACTH) and angiotensin-II-stimulated aldosterone release, and were compared with the mineralocorticoid receptor antagonist eplerenone in a randomized, placebo-controlled study conducted in 99 healthy human subjects. The effects of LCI699 and eplerenone on cardiac and renal sequelae of aldosterone excess were investigated in a double-transgenic rat (dTG rat) model overexpressing human renin and angiotensinogen.. Rat and monkey in vivo models of stimulated aldosterone release predicted human dose- and exposure-response relationships, but overestimated the selectivity of LCI699 in humans. In the dTG rat model, LCI699 dose-dependently blocked increases in aldosterone, prevented development of cardiac and renal functional abnormalities independent of blood pressure changes, and prolonged survival. Eplerenone prolonged survival to a similar extent, but was less effective in preventing cardiac and renal damage. In healthy human subjects, LCI699 0.5 mg selectively reduced plasma and 24 h urinary aldosterone by 49 ± 3% and 39 ± 6% respectively (Day 1, mean ± SEM; P < 0.001 vs placebo), which was associated with natriuresis and an increase in plasma renin activity. Doses of LCI699 greater than 1 mg inhibited basal and ACTH-stimulated cortisol. Eplerenone 100 mg increased plasma and 24 h urinary aldosterone while stimulating natriuresis and increasing renin activity. In contrast to eplerenone, LCI699 increased the aldosterone precursor 11-deoxycorticosterone and urinary potassium excretion.. These results provide new insights into the cardiac and renal effects of inhibiting aldosterone synthase in experimental models and translation of the hormonal effects to humans. Selective inhibition of aldosterone synthase appears to be a promising approach to treat diseases associated with aldosterone excess.

Topics: Angiotensinogen; Animals; Cytochrome P-450 CYP11B2; Disease Models, Animal; Double-Blind Method; Eplerenone; Haplorhini; Heart; Humans; Imidazoles; Kidney; Male; Placebos; Pyridines; Rats; Rats, Sprague-Dawley; Rats, Transgenic; Renin; Spironolactone; Translational Research, Biomedical

Osteoarthritis (OA) is a multifactorial degenerative disease marked by the progressive deterioration of articular cartilage with inflammation of the synovium. OA's main symptoms include pain and function loss. Monosodium Iodoacetate (MIA) experimental model is widely-used for OS induction since it produces symptoms comparable to those occurring in humans.. Thirty-two rats were divided into four groups (n = 8). The 1st group received saline and included the normal-control rats. Groups 2-4 received intra-articular injections of MIA (3 mg/50 μL) in the rats' knee joints to induce OA. Group 2 included the MIA-control rats. Groups 3 and 4 received intra-articular MIA followed by a 14-day oral eplerenone (50 and 100 mg/kg); respectively.. Intra-articular injection of MIA in rats' knee joints caused significant inflammation and pain, elevation of Akt and ERK gene expression in knee joints along with significant alterations in the histological pictures of knee joints and OARSI scores. RANKL/OPG Axis was significantly disrupted.. Eplerenone treatment produced a significant improvement in motor coordination and spontaneous locomotor activity in rats and modulated the key inflammatory mediators in OA (TNF-α, NF-κβ, and IL-6). Eplerenone also suppressed the qRT-PCR gene expression of Akt and ERK in knee joint tissues and improved the histological pictures and OARSI scores of knee joints of treated rats. Eplerenone caused a decline in RANKL concentration accompanied by a rise in OPG concentration thus modulating the RANKL/OPG Axis. Consequently, eplerenone is a candidate for OA therapy due to its potential anti-inflammatory effects.

Topics: Animals; Cartilage, Articular; Disease Models, Animal; Eplerenone; Humans; Inflammation; Iodoacetic Acid; Osteoarthritis, Knee; Pain; Proto-Oncogene Proteins c-akt; Rats

Cardiorenal syndrome (CRS) is the leading cause of death associated with chronic kidney disease (CKD) and end-stage renal disease (ESRD). However, the underlying mechanisms of CRS are still poorly understood. Here, we studied a CKD model of unilateral ureteral obstruction (UUO) and observed pathological cardiac fibrosis and lymphangiogenesis in 180-day old UUO rats, in which inflammatory injury plays a major role. In addition, treatment of UUO rats with eplerenone, a mineralocorticoid receptor blocker (MRB), significantly reduced cardiac lymphangiogenesis and fibrosis. In conclusion, our experimental results showed that cardiac lymphangiogenesis in long-term UUO rats may be involved in the formation of cardiac fibrosis and that eplerenone can alleviate lymphangiogenesis and cardiac fibrosis by inhibiting inflammation.

Topics: Animals; Disease Models, Animal; Eplerenone; Fibrosis; Kidney; Lymphangiogenesis; Rats; Renal Insufficiency, Chronic; Ureteral Obstruction

Recent mounting studies showed that neuroinflammation caused by surgery or anesthesia is closely related to postoperative cognitive dysfunction (POCD). This study investigated the effect of mineralocorticoid receptor (MR) on neuroinflammation and POCD. To detect the MR effect in an animal model, we randomly divided rats into control, anesthesia, and surgery groups. To determine whether the MR-specific blocker eplerenone (EPL) could improve cognitive dysfunction, we assigned other animals into the control, surgery and EPL treatment, and surgery groups. Cognitive function was detected using the Morris water maze. Serum cytokine levels were measured by ELISA, and the histopathological changes of hippocampal neurons were identified by hematoxylin/eosin and Nissl staining. Our research confirmed that anesthesia and surgical stimulation could lead to IL-1β, IL-6, and TNF-α activation and hippocampal neuronal degeneration and pathological damage. MR was upregulated in the hippocampus under cognitive impairment condition. Additionally, EPL could alleviate inflammatory activation and neuronal damage by exerting neuroprotective effects. The preclinical model of sevoflurane anesthesia/splenectomy implied that MR expression is upregulated by regulating the neuroinflammation in the brain under POCD condition. Manipulating the MR expression by EPL could improve the inflammation activation and neuronal damage.

Topics: Administration, Inhalation; Administration, Oral; Anesthesia, Inhalation; Animals; Disease Models, Animal; Eplerenone; Hippocampus; Humans; Male; Mineralocorticoid Receptor Antagonists; Neurons; Postoperative Cognitive Complications; Rats; Receptors, Mineralocorticoid; Sevoflurane; Signal Transduction; Splenectomy

Progression of chronic kidney disease (CKD) to uremia is often accompanied by varying degrees of lung damage and this is also an important cause of death. Although there are many studies on the mechanism of lung injury, it is not clearly understood. Inflammatory macrophages may associated with fibrosis in the lungs. Here, we investigated the role of macrophage-myofibroblast transition (MMT) in lung fibrosis with unilateral ureteral obstruction (UUO) rats. We found that cells undergoing MMT accounted for an important part of the myofibroblast population, and correlated with lung fibrosis, MMT cells in lungs have a predominant M2 phenotype, and this process was attenuated after treatment with eplerenone. In conclusion, our studies provide a possible mechanism for UUO-induced kidney damage and lung injury, indicating the possibility of using eplerenone, a mineralocorticoid receptor blocker, to treat UUO to reduce kidney damage and protect lung function.

Topics: Animals; Cell Differentiation; Disease Models, Animal; Eplerenone; Humans; Macrophages; Male; Mineralocorticoid Receptor Antagonists; Myofibroblasts; Protective Agents; Pulmonary Fibrosis; Rats; Rats, Wistar; Renal Insufficiency, Chronic; Ureteral Obstruction

[Figure: see text].

Topics: Animals; Antihypertensive Agents; Disease Models, Animal; Endothelial Cells; Endothelium, Vascular; Eplerenone; Hypertension, Pulmonary; Male; Mice; Mice, Knockout; Mineralocorticoid Receptor Antagonists; Receptors, Mineralocorticoid; Treatment Outcome; Vascular Remodeling

Dementia resulting from small vessel diseases (SVDs) of the brain is an emerging epidemic for which there is no treatment. Hypertension is the major risk factor for SVDs, but how hypertension damages the brain microcirculation is unclear. Here, we show that chronic hypertension in a mouse model progressively disrupts on-demand delivery of blood to metabolically active areas of the brain (functional hyperemia) through diminished activity of the capillary endothelial cell inward-rectifier potassium channel, Kir2.1. Despite similar efficacy in reducing blood pressure, amlodipine, a voltage-dependent calcium-channel blocker, prevented hypertension-related damage to functional hyperemia whereas losartan, an angiotensin II type 1 receptor blocker, did not. We attribute this drug class effect to losartan-induced aldosterone breakthrough, a phenomenon triggered by pharmacological interruption of the renin-angiotensin pathway leading to elevated plasma aldosterone levels. This hypothesis is supported by the finding that combining losartan with the aldosterone receptor antagonist eplerenone prevented the hypertension-related decline in functional hyperemia. Collectively, these data suggest Kir2.1 as a possible therapeutic target in vascular dementia and indicate that concurrent mineralocorticoid aldosterone receptor blockade may aid in protecting against late-life cognitive decline in hypertensive patients treated with angiotensin II type 1 receptor blockers.

Topics: Amlodipine; Angiotensin II Type 1 Receptor Blockers; Animals; Antihypertensive Agents; Cerebral Small Vessel Diseases; Cerebrovascular Circulation; Dementia, Vascular; Disease Models, Animal; Drug Therapy, Combination; Eplerenone; Heart Disease Risk Factors; Humans; Hyperemia; Hypertension; Losartan; Male; Mice; Microvessels; Potassium Channels, Inwardly Rectifying; Renin-Angiotensin System

When Zika virus emerged as a public health emergency there were no drugs or vaccines approved for its prevention or treatment. We used a high-throughput screen for Zika virus protease inhibitors to identify several inhibitors of Zika virus infection. We expressed the NS2B-NS3 Zika virus protease and conducted a biochemical screen for small-molecule inhibitors. A quantitative structure-activity relationship model was employed to virtually screen ∼138,000 compounds, which increased the identification of active compounds, while decreasing screening time and resources. Candidate inhibitors were validated in several viral infection assays. Small molecules with favorable clinical profiles, especially the five-lipoxygenase-activating protein inhibitor, MK-591, inhibited the Zika virus protease and infection in neural stem cells. Members of the tetracycline family of antibiotics were more potent inhibitors of Zika virus infection than the protease, suggesting they may have multiple mechanisms of action. The most potent tetracycline, methacycline, reduced the amount of Zika virus present in the brain and the severity of Zika virus-induced motor deficits in an immunocompetent mouse model. As Food and Drug Administration-approved drugs, the tetracyclines could be quickly translated to the clinic. The compounds identified through our screening paradigm have the potential to be used as prophylactics for patients traveling to endemic regions or for the treatment of the neurological complications of Zika virus infection.

Topics: Animals; Antiviral Agents; Artificial Intelligence; Chlorocebus aethiops; Disease Models, Animal; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Immunocompetence; Inhibitory Concentration 50; Methacycline; Mice, Inbred C57BL; Protease Inhibitors; Quantitative Structure-Activity Relationship; Small Molecule Libraries; Vero Cells; Zika Virus; Zika Virus Infection

The incidence of depression doubles in diabetic patients and is associated with poor outcomes. Studies indicate that renin-angiotensin-aldosterone system inhibitors (RAASi) might relieve depression, however the mechanism of action is not well understood. We recently showed that angiotensin receptor blockers have antidepressant effects in experimental diabetes comorbid depression. Here we investigated whether all types of RAASi exhibit antidepressant and neuroprotective properties. Diabetes was induced by streptozotocin in adult male Wistar rats. After 5 weeks of diabetes, rats were treated per os with non-pressor doses of enalapril, ramipril, spironolactone or eplerenone for 2 weeks. Behavior was evaluated using forced swim test and open field test. Inflammatory response and brain-derived neurotrophic factor (BDNF) signaling were investigated in the hippocampus. Both ACEi and MR antagonists reversed diabetes-induced behavioral despair confirming their antidepressant-like effect. This may occur via alterations in hippocampal cytokine-mediated inflammatory response. Repressed BDNF production was restored by RAASi. Both ACEi and MR antagonists facilitated the BDNF-tropomyosin receptor kinase B-cAMP response element-binding protein signaling pathway as part of their neuroprotective effect. These data highlight the important benefits of ACEi and MR antagonists in the treatment of diabetes-associated depressive symptoms. Our novel findings support the link between diabetes comorbid depression, inflammation and repressed BDNF signaling. RAASi could provide new therapeutic options to improve the outcomes of both disorders.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Antidepressive Agents; Antihypertensive Agents; Behavior, Animal; Blood Pressure; Depression; Diabetes Mellitus, Experimental; Disease Models, Animal; Down-Regulation; Enalapril; Eplerenone; Male; Mineralocorticoid Receptor Antagonists; Ramipril; Rats; Rats, Wistar; Renin-Angiotensin System; Spironolactone

Topics: Animals; Arrhythmias, Cardiac; Calcium Signaling; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Disease Models, Animal; Eplerenone; Female; Fibrosis; Male; Mice; Mice, Inbred C57BL; Mineralocorticoid Receptor Antagonists; Receptors, Mineralocorticoid; Signal Transduction; Smad3 Protein; Transforming Growth Factor beta

Myocardial infarction (MI) is a major cause of death worldwide. Here, we identify the macrophage MR (mineralocorticoid receptor) as a crucial pathogenic player in cardiac wound repair after MI. Seven days after left coronary artery ligation, mice with myeloid cell-restricted MR deficiency compared with WT (wild type) controls displayed improved cardiac function and remodeling associated with enhanced infarct neovascularization and scar maturation. Gene expression profiling of heart-resident and infarct macrophages revealed that MR deletion drives macrophage differentiation in the ischemic microenvironment toward a phenotype outside the M1/M2 paradigm, with regulation of multiple interrelated factors controlling wound healing and tissue repair. Mechanistic and functional data suggest that inactivation of the macrophage MR promotes myocardial infarct healing through enhanced efferocytosis of neutrophils, the suppression of free radical formation, and the modulation of fibroblast activation state. Crucially, targeted delivery of MR antagonists to macrophages, with a single administration of RU28318 or eplerenone-containing liposomes at the onset of MI, improved the healing response and protected against cardiac remodeling and functional deterioration, offering an effective and unique therapeutic strategy for cardiac repair.

Topics: Animals; Cell Differentiation; Cellular Microenvironment; Disease Models, Animal; Eplerenone; Gene Expression Profiling; Heart; Liposomes; Macrophages; Mice; Mineralocorticoid Receptor Antagonists; Myocardial Infarction; Myocardium; Receptors, Mineralocorticoid; Ventricular Remodeling; Wound Healing

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

To study the promotive effect of salt-induced hypertension on crystal deposition and urolithiasis using a salt-sensitive rat hypertension model.. Hyperoxaluria and hypercalciuria were induced in male Dahl salt-sensitive rats with administration of ethylene glycol and alfacalcidol. Hypertension was induced by a high-salt diet. Eplerenone, a selective mineralocorticoid receptor antagonist, was given. Blood and urine were collected to evaluate renal function, electrolytes and the blood renin-angiotensin-aldosterone system. Renal calcium content was also evaluated. Histological examination, transcriptome analysis with DNA microarray and semiquantitative reverse transcriptase polymerase chain reaction were carried out.. A high-salt diet increased crystal deposition in Dahl salt-sensitive rats with hypertension, and eplerenone administration significantly suppressed it. The mRNA expression profile was associated with crystal formation, growth, adhesion and cellular injury, and it was regulated in the group exposed to a high-salt diet and ethylene glycol.. A high-salt diet has a promotive effect on salt-sensitive hypertension and urolithiasis. This promotive effect can be prevented by eplerenone administration. Hence, salt-sensitive hypertension has promotive effects on crystal deposition in Dahl salt-sensitive rats.

Topics: Animals; Blood Pressure; Calcium; Disease Models, Animal; Eplerenone; Ethylene Glycol; Humans; Hydroxycholecalciferols; Hypertension; Kidney; Male; Mineralocorticoid Receptor Antagonists; Rats; Rats, Inbred Dahl; Renin-Angiotensin System; Sodium Chloride, Dietary; Urolithiasis

Atrial fibrillation (AF) is the most common progressive cardiac arrhythmia and is often associated with rapid contraction in both atria and ventricles. The role of atrial energy and metabolic homeostasis in AF progression is under-investigated.. To determine the remodeling of energy metabolism during persistent AF and the effect of eplerenone (EPL), an aldosterone inhibitor, on metabolic homeostasis.. A nonsustained atrial pacing sheep model was developed to simulate the progression of AF from paroxysmal to persistent. Metabolomic and proteomic analyses at termination of the experiment were used to analyze atrial tissues obtained from sheep in sham, sugar pill (SP) and EPL-treated groups.. Proteomic analysis indicated that compared to the sham group, in SP group, fatty acid (FA) synthesis, FA oxidation, tricarboxylic acid (TCA) cycle processes and amino acids (AAs) transport and metabolism were reduced, while glycolytic processes were increased. In metabolomic analysis, the levels of intermediate metabolites of the glycolytic pathways, including 2-phosphoglyceric acid (2 PG), 1,3-bisphosphoglyceric acid (1,3 PG), and pyruvate, HBP (uridine diphosphate-N-acetylglucosamine, UDP-GlcNAc), TCA (citrate) and AAs were greater while the levels of the majority of lipid classes, including phosphatidic acid (PA), phosphatidylcholine (PC), phosphatidylglycerol (PG), glycerophosphoglycerophosphates (PGP), glycerophosphoinositols (PI) and glycerophosphoserines (PS), were decreased in the atria of SP group than in those of sham group. EPL-pretreatment decreased the expression of glut4 and increased the content of acylcarnitines and lipids, such as lyso phospholipids, phospholipids and neutral lipids.. In the metabolic remodeling during AF, glucose and lipid metabolism were up- and down-regulated, respectively, to sustain TCA cycle anaplerosis. EPL partialy reversed the metabolic shifting.

Topics: Animals; Atrial Fibrillation; Citric Acid Cycle; Disease Models, Animal; Energy Metabolism; Eplerenone; Glucose; Homeostasis; Lipid Metabolism; Male; Metabolic Networks and Pathways; Mineralocorticoid Receptor Antagonists; Myocardium; Sheep

Anthracyclines such as doxorubicin are widely used in cancer therapy but their use is limited by cardiotoxicity. Up to date there is no established strategy for the prevention of anthracyclin-induced heart failure. In this study, we evaluated the role of the cardiac myocyte mineralocorticoid receptor (MR) during doxorubicin-induced cardiotoxicity.. A single high-dose or repetitive low-dose doxorubicin administration lead to markedly reduced left ventricular function in mice. Treatment with the MR antagonist eplerenone prevented doxorubicin-induced left ventricular dysfunction. In order to identify the cell types and molecular mechanisms involved in this beneficial effect we used a mouse model with cell type-specific MR deletion in cardiac myocytes. Cardiac myocyte MR deletion largely reproduced the effect of pharmacological MR inhibition on doxorubicin-induced cardiotoxicity. RNAseq from isolated cardiac myocytes revealed a repressive effect of doxorubicin on gene expression which was prevented by MR deletion.. We show here that (i) eplerenone prevents doxorubicin-induced left ventricular dysfunction in mice, and (ii) this beneficial effect is related to inhibition of MR in cardiac myocytes. Together with present clinical trial data our findings suggest that MR antagonism may be appropriate for the prevention of doxorubicin-induced cardiotoxicity.

Topics: Animals; Atrophy; Cardiotoxicity; Disease Models, Animal; Doxorubicin; Eplerenone; Female; Fibrosis; Mice, Inbred C57BL; Mice, Knockout; Mineralocorticoid Receptor Antagonists; Receptors, Mineralocorticoid; Ventricular Dysfunction, Left; Ventricular Function, Left; Ventricular Remodeling

Topics: Animals; Disease Models, Animal; Eplerenone; Metabolic Syndrome; Mineralocorticoid Receptor Antagonists; Osteoarthritis; Rats

Clinical studies suggest beneficial effects of renin-angiotensin system blockade for prevention of left ventricular (LV) dysfunction after chemotherapy. However, the efficacy of this strategy as primary prevention has been poorly studied. This study aimed at identifying the pathophysiological mechanisms by which mineralocorticoid receptor antagonism (MRA) or angiotensin converting enzyme inhibition (ACEi) provide protection against doxorubicin-induced cardiotoxicity (DIC) in mouse models of acute and chronic toxicity.. Acute DIC was induced by a single injection of Dox at 15 mg/kg and chronic DIC applied 5 injections of Dox at 4 mg/kg/week. MRA was achieved using eplerenone or cardiomyocyte-specific ablation of the MR gene in transgenic mice and ACEi using enalapril. Drugs were provided with the first dose of Dox and applied until the end of the study. In both model of DIC, Dox induced cardiac atrophy with decreased LV volume, reduced cardiomyocyte cell size, and cardiac dysfunction. In the acute model, neither MRA nor ACEi protected against these manifestations of DIC. In the chronic model, concomitant treatment with eplerenone did not protect against DIC and drastically increased plasma aldosterone levels and cardiac levels of angiotensin II type 1 receptor and of connective tissue growth factor (CTGF), as observed in acute DIC. Enalapril treatment in the chronic model, however, protected against cardiac dysfunction and cardiomyocyte atrophy and was associated with increased activation of the PI3K/AKT/mTOR pathway along with normal levels of CTGF.. Enalapril and eplerenone disparately impact on cellular signalling in DIC. Eplerenone, on top of Dox treatment was not protective and associated with increased levels of plasma aldosterone and of cardiac CTGF. In contrast, we show that primary prevention with enalapril preserves LV morphology and function in a clinically relevant model of chronic DIC, with increased stimulation of the PI3K/AKT/mTOR axis and normal CTGF levels suggesting potential therapeutic implications.

Topics: Aldosterone; Angiotensin-Converting Enzyme Inhibitors; Animals; Cardiotoxicity; Connective Tissue Growth Factor; Disease Models, Animal; Doxorubicin; Enalapril; Eplerenone; Male; Mice, Inbred C57BL; Mice, Knockout; Mineralocorticoid Receptor Antagonists; Myocytes, Cardiac; Phosphatidylinositol 3-Kinase; Primary Prevention; Proto-Oncogene Proteins c-akt; Receptor, Angiotensin, Type 1; Receptors, Mineralocorticoid; Renin-Angiotensin System; Signal Transduction; TOR Serine-Threonine Kinases; Ventricular Dysfunction, Left; Ventricular Function, Left

Spironolactone (SPL) improves endothelial dysfunction and survival in heart failure. Immune modulation, including poorly understood mineralocorticoid receptor (MR)-independent effects of SPL might contribute to these benefits and possibly be useful in other inflammatory cardiovascular diseases such as pulmonary arterial hypertension.. Using human embryonic kidney cells (HEK 293) expressing specific nuclear receptors, SPL suppressed NF-κB and AP-1 reporter activity independent of MR and other recognized nuclear receptor partners. NF-κB and AP-1 DNA binding were not affected by SPL and protein synthesis blockade did not interfere with SPL-induced suppression of inflammatory signalling. In contrast, proteasome blockade to inhibit degradation of xeroderma pigmentosum group B complementing protein (XPB), a subunit of the general transcription factor TFIIH, or XPB overexpression both prevented SPL-mediated suppression of inflammation. Similar to HEK 293 cells, a proteasome inhibitor blocked XPB loss and SPL suppression of AP-1 induced target genes in human pulmonary artery endothelial cells (PAECs). Unlike SPL, eplerenone (EPL) did not cause XPB degradation and failed to similarly suppress inflammatory signalling. SPL combined with siRNA XPB knockdown further reduced XPB protein levels and had the greatest effect on PAEC inflammatory gene transcription. Using chromatin-immunoprecipitation, PAEC target gene susceptibility to SPL was associated with low basal RNA polymerase II (RNAPII) occupancy and TNFα-induced RNAPII and XPB recruitment. XP patient-derived fibroblasts carrying an N-terminal but not C-terminal XPB mutations were insensitive to both SPL-mediated XPB degradation and TNFα-induced target gene suppression. Importantly, SPL treatment decreased whole lung XPB protein levels in a monocrotaline rat model of pulmonary hypertension and reduced inflammatory markers in an observational cohort of PAH patients.. SPL has important anti-inflammatory effects independent of aldosterone and MR, not shared with EPL. Drug-induced, proteasome-dependent XPB degradation may be a useful therapeutic approach in cardiovascular diseases driven by inflammation.

Topics: Animals; Anti-Inflammatory Agents; Disease Models, Animal; DNA Helicases; DNA-Binding Proteins; Endothelial Cells; Eplerenone; Fibroblasts; HEK293 Cells; Humans; Hypertension, Pulmonary; Inflammation Mediators; Lung; Mineralocorticoid Receptor Antagonists; Mutation; NF-kappa B; Proteasome Endopeptidase Complex; Proteolysis; Pulmonary Artery; Rats, Sprague-Dawley; Retrospective Studies; RNA Polymerase II; Signal Transduction; Spironolactone; Transcription Factor AP-1; Transcription Factor TFIIH

The number of patients with adrenal aldosterone-producing adenomas (APAs) has gradually increased. However, even after adenoma resection, some patients still suffer from high systolic blood pressure (SBP), which is possibly due to great arterial remodeling. Moreover, mineralocorticoid receptors (MRs) were found to be expressed in vascular smooth muscle cells (VSMCs). This study aims to determine whether MR antagonism protects the aorta from aldosterone-induced aortic remolding. Male rats were subcutaneously implanted with an osmotic minipumps and randomly divided into four groups: control; aldosterone (1 μg/h); aldosterone plus a specific MR antagonist, eplerenone (100 mg/kg/day); and aldosterone plus a vasodilator, hydralazine (25 mg/kg/day). After 8 weeks of infusion, aortic smooth muscle cell proliferation and collagen deposition, as well as the MDM2 and TGF-β1 expression levels in the aorta, were examined. Model rats with APAs were successfully constructed. Compared with the control rats, the model rats exhibited (1) marked SBP elevation, (2) no significant alteration in aortic morphology, (3) increased VSMC proliferation and MDM2 expression in the aorta, and (4) enhanced total collagen and collagen III depositions in the aorta, accompanied with up-regulated expression of TGF-β1. These effects were significantly inhibited by co-administration with eplerenone but not with hydralazine. These findings suggested that specific MR antagonism protects the aorta from aldosterone-induced VSMC proliferation and collagen deposition.

Topics: ACTH-Secreting Pituitary Adenoma; Aldosterone; Animals; Antihypertensive Agents; Aorta; Cell Proliferation; Collagen; Disease Models, Animal; Eplerenone; Hydralazine; Hypertension; Male; Mineralocorticoid Receptor Antagonists; Muscle, Smooth, Vascular; Proto-Oncogene Proteins c-mdm2; Random Allocation; Rats, Sprague-Dawley; Spironolactone; Transforming Growth Factor beta; Vascular Remodeling; Vasodilator Agents

Obesity-related glomerulopathy (ORG) is morphologically characterized by glomerulomegaly with or without observable focal segmental glomerulosclerosis under light microscope, with decreased podocyte density and number, and with increased foot‑process width observed under electron microscope. The severity of podocyte injury is correlated with the degree of proteinuria and renal dysfunction. However, the pathogenesis of ORG is not well understood. The aim of the present study was to explore the possible pathogenic role of aldosterone (ALDO) in ORG. In the in vivo animal experiments, body weight, Lee's obesity index, abdominal fat index, urinary protein excretion, average glomerular diameter were significantly increased, the mRNA and protein expression of podocyte‑associated molecules including nephrin, podocin, podoplanin and podocalyxin were significantly reduced, and the Wnt/β‑catenin signaling pathway was activated in ORG model mice compared with the Control mice, whereas the administration of spironolactone significantly ameliorated these effects. In the in vitro experiments on cultured podocytes, the mRNA and protein expression levels of the aforementioned podocyte‑associated molecules were significantly downregulated and the Wnt/β‑catenin signaling pathway was activated following ALDO stimulation, whereas eplerenone significantly attenuated all the above effects. Dickkopf‑related protein 1 (DKK1), an inhibitor of Wnt/β‑catenin signaling pathway, also reduced the effects of ALDO exposure on the expression of podocyte‑associated molecules. The present study hypothesized that ALDO may be involved in the pathogenesis of ORG through the activation of Wnt/β‑catenin signaling pathway in podocytes.

Topics: Aldosterone; Animals; beta Catenin; Disease Models, Animal; Down-Regulation; Eplerenone; Glomerulonephritis; Intercellular Signaling Peptides and Proteins; Intracellular Signaling Peptides and Proteins; Kidney Cortex; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; Obesity; Podocytes; Sialoglycoproteins; Spironolactone; Wnt Proteins; Wnt Signaling Pathway

Topics: Animals; Biological Availability; Disease Models, Animal; Eplerenone; Gene Expression Regulation; Heart Failure; Mice; Mineralocorticoid Receptor Antagonists; Myocytes, Cardiac; Naphthyridines; Tenascin

Topics: Aldosterone; Analysis of Variance; Animals; Calcium; Disease Models, Animal; Eplerenone; Femur; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Gitelman Syndrome; Glucuronidase; Hydrochlorothiazide; Hypovolemia; Klotho Proteins; Male; Mice; Mice, Knockout; Mineralocorticoid Receptor Antagonists; Parathyroid Hormone; Phosphates; Receptor, Fibroblast Growth Factor, Type 1; Receptors, Drug; Sodium Chloride Symporters; Thiazides

Aldosterone is a mineralocorticoid hormone critically involved in arterial blood pressure regulation. Although pharmacological aldosterone antagonism reduces mortality and morbidity among patients with severe left-sided heart failure, the contribution of aldosterone to the pathobiology of pulmonary arterial hypertension (PAH) and right ventricular (RV) heart failure is not fully understood.. The effects of Eplerenone (0.1% Inspra® mixed in chow) on pulmonary vascular and RV remodeling were evaluated in mice with pulmonary hypertension (PH) caused by Sugen5416 injection with concomitant chronic hypoxia (SuHx) and in a second animal model with established RV dysfunction independent from lung remodeling through surgical pulmonary artery banding.. Preventive Eplerenone administration attenuated the development of PH and pathological remodeling of pulmonary arterioles. Therapeutic aldosterone antagonism - starting when RV dysfunction was established - normalized mineralocorticoid receptor gene expression in the right ventricle without direct effects on either RV structure (Cardiomyocyte hypertrophy, Fibrosis) or function (assessed by non-invasive echocardiography along with intra-cardiac pressure volume measurements), but significantly lowered systemic blood pressure.. Our data indicate that aldosterone antagonism with Eplerenone attenuates pulmonary vascular rather than RV remodeling in PAH.

Topics: Animals; Arterial Pressure; Disease Models, Animal; Eplerenone; Heart Ventricles; Hypertension, Pulmonary; Hypoxia; Male; Mice; Mice, Inbred C57BL; Mineralocorticoid Receptor Antagonists; Pulmonary Artery; Ventricular Dysfunction, Right; Ventricular Remodeling

Managing the cardiovascular complications of renal failure is a major therapeutic challenge in clinical practice. Mineralocorticoid Receptor (MR) blockade is a highly effective strategy for the management of heart failure, but the use of MR antagonists (MRA) is limited by their side effects rendering them contraindicated in patients with renal failure. Finerenone is a new non-steroidal MRA that shows fewer hyperkaliaemic events than the traditional steroidal MRAs and could therefore represent an alternative to these molecules in patients with damaged kidney function. The aim of this study is to characterize the effects of Finerenone on the cardiac complications of renal failure in a mouse model of chronic kidney disease (CKD). CKD was induced by subtotal nephrectomy (Nx), and finerenone was administered at a low dose (2.5 mg/kg/d) from week 4 to week 10 post-Nx. Cardiac function was assessed by echocardiography and invasive hemodynamics while cardiac fibrosis was measured by Sirius Red staining. Renal failure induced cardiac systolic and diastolic dysfunctions in the untreated CKD mice, as well as minor changes on cardiac structure. We also observed alterations in the phosphorylation of proteins playing key roles in the calcium handling (Phospholamban, Calmodulin kinase II) in these mice. Finerenone prevented most of these lesions with no effects on neither the renal dysfunction nor kaliemia. The benefits of finerenone suggest that activation of MR is involved in the cardiac complication of renal failure and strengthen previous studies showing beneficial effects of MRA in patients with CKD.

Topics: Animals; Disease Models, Animal; Eplerenone; Heart Failure, Diastolic; Hemodynamics; Humans; Mice; Mineralocorticoid Receptor Antagonists; Naphthyridines; Receptors, Mineralocorticoid; Renal Insufficiency, Chronic

Spironolactone, eplerenone, chlorothiazide and furosemide are diuretics that have been suggested to have antinociceptive properties, for example via mineralocorticoid receptor antagonism. In co-administration, diuretics might enhance the antinociceptive effect of opioids via pharmacodynamic and pharmacokinetic mechanisms. Effects of spironolactone (100 mg/kg, i.p.), eplerenone (100 mg/kg, i.p.), chlorothiazide (50 mg/kg, i.p.) and furosemide (100 mg/kg, i.p.) were studied on acute oxycodone (0.75 mg/kg, s.c.)- and morphine (3 mg/kg, s.c.)-induced antinociception using tail-flick and hot plate tests in male Sprague Dawley rats. The diuretics were administered 30 min. before the opioids, and behavioural tests were performed 30 and 90 min. after the opioids. Concentrations of oxycodone, morphine and their major metabolites in plasma and brain were quantified by mass spectrometry. In the hot plate test at 30 and 90 min., spironolactone significantly enhanced the antinociceptive effect (% of maximum possible effect) of oxycodone from 10% to 78% and from 0% to 50%, respectively, and that of morphine from 12% to 73% and from 4% to 83%, respectively. The brain oxycodone and morphine concentrations were significantly increased at 30 min. (oxycodone, 46%) and at 90 min. (morphine, 190%). We did not detect any independent antinociceptive effects with the diuretics. Eplerenone and chlorothiazide did not enhance the antinociceptive effect of either opioid. The results suggest that spironolactone enhances the antinociceptive effect of both oxycodone and morphine by increasing their concentrations in the central nervous system.

Topics: Analgesics; Analgesics, Opioid; Animals; Behavior, Animal; Brain; Chlorothiazide; Disease Models, Animal; Diuretics; Drug Interactions; Drug Therapy, Combination; Eplerenone; Furosemide; Male; Morphine; Neurons; Oxycodone; Pain; Rats, Sprague-Dawley; Spironolactone; Tissue Distribution

There is increasing evidence for a crucial role of aberrant mineralocorticoid receptor (MR) activation in heart failure, with clinical studies showing beneficial effects of MR blockade. However, the mechanisms of MR activation in heart failure remain unclear. In this study, we observed that the small GTPase Rac1 contributes to myocardial MR activation, whereas Rac1-MR pathway activation leads to cardiac dysfunction. Mouse hearts subjected to chronic pressure overload induced by transverse aortic constriction showed Rac1 activation and increased nuclear accumulation of MR and expression of MR target genes, suggesting MR activation. Pharmacological inhibition of Rac1 and heterozygous deletion of Rac1 in cardiomyocytes suppressed Rac1-induced MR signaling and reduced NADPH oxidase 4 gene induction and reactive oxygen species overproduction, which attenuated transverse aortic constriction-induced cardiac hypertrophy and dysfunction. Consistently, treatment with the selective MR antagonist eplerenone blocked transverse aortic constriction-induced MR signaling and NADPH oxidase 4 gene upregulation, which improved cardiac hypertrophy and dysfunction. These findings suggest that Rac1-MR pathway activation in the myocardium is involved in development of heart failure induced by pressure load via recruitment of the responsible isoform of NADPH oxidase. Thus, the cardiac Rac1-MR-NADPH oxidase 4 pathway may be a therapeutic target for treatment of the pressure-overloaded heart.

Topics: Animals; Disease Models, Animal; Eplerenone; Heart Failure; Male; Mice; Mice, Inbred C57BL; Mineralocorticoid Receptor Antagonists; Myocytes, Cardiac; Neuropeptides; Oxidative Stress; rac1 GTP-Binding Protein; Receptors, Mineralocorticoid; Signal Transduction; Spironolactone; Ventricular Pressure; Ventricular Remodeling

Pharmacological blockade of mineralocorticoid receptors (MR) is known as an efficacious therapy in chronic heart failure. Therapy with steroidal MR antagonists such as spironolactone or eplerenone (EPL) is often limited because of side effects. Recently, a new highly selective and potent, nonsteroidal MR antagonist, finerenone (FIN), has been developed. To investigate the effects of FIN on pressure-induced cardiac hypertrophy, the transverse aortic constriction (TAC) model was used in C57BL/6 mice treated with FIN (10 mg·kg·d), EPL (200 mg·kg·d) or vehicle (VEH). First, we analyzed cardiac gene expression 4 weeks after TAC using a pathway-focused quantitative polymerase chain reaction array. FIN caused a distinct cardiac gene expression profile compared to VEH and EPL, including differential expression of BNP (brain natriuretic peptide) and Tnnt2 (troponin T type 2). FIN treatment led to a significant reduction of TAC-induced left ventricular (LV) wall thickening assessed by echocardiography. In accordance, FIN-treated mice showed a significant lower increase of calculated left ventricular mass compared with VEH- and EPL-treated mice (FIN: 28.4 ± 3.7 mg; EPL: 38.4 ± 4.3 mg; VEH: 39.3 ± 3.1 mg; P < 0.05). These data show beneficial effects of nonsteroidal MR antagonism by FIN on left ventricular mass development in pressure overload associated with a distinct cardiac gene expression profile.

Topics: Animals; Cardiomegaly; Disease Models, Animal; Eplerenone; Gene Expression; Male; Mice; Mice, Inbred C57BL; Mineralocorticoid Receptor Antagonists; Naphthyridines; Natriuretic Peptide, Brain; Spironolactone; Troponin T; Ventricular Remodeling

Vascular calcification, which is common in the elderly and in patients with atherosclerosis, diabetes and chronic renal disease, increases the risk of cardiovascular morbidity and mortality. It is a complex, active and highly regulated cellular process that resembles physiological bone formation. It has previously been established that pharmacological doses of glucocorticoids facilitate arterial calcification. However, the consequences for vascular calcification of endogenous glucocorticoid elevation have yet to be established. Glucocorticoids (cortisol, corticosterone) are released from the adrenal gland, but can also be generated within cells from 11-keto metabolites of glucocorticoids (cortisone, 11-dehydrocorticosterone [11-DHC]) by the enzyme, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). In the current study we hypothesized that endogenous glucocorticoids facilitate vascular smooth muscle cell (VSMC) calcification and investigated the receptor-mediated mechanism underpinning this process. In vitro studies revealed increased phosphate-induced calcification in mouse VSMCs following treatment for 7days with corticosterone (100nM; 7.98 fold; P<0.01), 11-DHC (100nM; 7.14 fold; P<0.05) and dexamethasone (10nM; 7.16 fold; P<0.05), a synthetic glucocorticoid used as a positive control. Inhibition of 11β-HSD isoenzymes by 10μM carbenoxolone reduced the calcification induced by 11-DHC (0.37 fold compared to treatment with 11-DHC alone; P<0.05). The glucocorticoid receptor (GR) antagonist mifepristone (10μM) had no effect on VSMC calcification in response to corticosterone or 11-DHC. In contrast, the mineralocorticoid receptor (MR) antagonist eplerenone (10μM) significantly decreased corticosterone- (0.81 fold compared to treatment with corticosterone alone; P<0.01) and 11-DHC-driven (0.64 fold compared to treatment with 11-DHC alone; P<0.01) VSMC calcification, suggesting this glucocorticoid effect is MR-driven and not GR-driven. Neither corticosterone nor 11-DHC altered the mRNA levels of the osteogenic markers PiT-1, Osx and Bmp2. However, DAPI staining of pyknotic nuclei and flow cytometry analysis of surface Annexin V expression showed that corticosterone induced apoptosis in VSMCs. This study suggests that in mouse VSMCs, corticosterone acts through the MR to induce pro-calcification effects, and identifies 11β-HSD-inhibition as a novel potential treatment for vascular calcification.

Topics: 11-beta-Hydroxysteroid Dehydrogenase Type 1; Animals; Apoptosis; Corticosterone; Disease Models, Animal; Eplerenone; Flow Cytometry; Glucocorticoids; Mice; Mice, Inbred C57BL; Mifepristone; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Phosphates; Receptors, Glucocorticoid; Receptors, Mineralocorticoid; RNA, Messenger; Spironolactone; Vascular Calcification

Plasma aldosterone is elevated in type 2 diabetes and obesity in experimental and clinical studies and can act to inhibit both glucose-stimulated insulin secretion by the β-cell and insulin signaling. Currently mineralocorticoid receptor antagonism is the best characterized treatment to ameliorate aldosterone-mediated effects. A second alternative is inhibition of aldosterone synthase, an approach with protective effects on end-organ damage in heart or kidney in animal models. The effect of aldosterone synthase inhibition on metabolic parameters in type 2 diabetes is not known. Therefore, male Zucker diabetic fatty (ZDF) rats were treated for 11 weeks with the aldosterone synthase inhibitor FAD286, beginning at 7 weeks of age. Results were compared with the mineralocorticoid receptor antagonist eplerenone. Plasma aldosterone was abolished by FAD286 and elevated more than 9-fold by eplerenone. The area under the curve calculated from an oral glucose tolerance test (OGTT) was lower and overall insulin response during OGTT was increased by FAD286. In contrast, eplerenone elevated blood glucose levels and blunted insulin secretion during the OGTT. Fasting glucose was lowered and fasting insulin was increased by FAD286 in the prediabetic state. Glycated hemoglobin was lowered by FAD286, whereas eplerenone showed no effect. We conclude that aldosterone synthase inhibition, in contrast to mineralocorticoid receptor antagonism, has the potential for beneficial effects on metabolic parameters in type 2 diabetes.

Topics: Adrenal Glands; Aldosterone; Animals; Blood Glucose; Body Weight; Cytochrome P-450 CYP11B2; Diabetes Mellitus, Type 2; Disease Models, Animal; Drug Evaluation, Preclinical; Eating; Eplerenone; Fadrozole; Glucose Tolerance Test; Glycated Hemoglobin; Insulin; Insulin Resistance; Insulin Secretion; Liver; Male; Mineralocorticoid Receptor Antagonists; Organ Size; Potassium; Random Allocation; Rats, Zucker; Sodium; Spironolactone; Triglycerides

Combined treatment with an angiotensin-converting enzyme inhibitor and a mineralocorticoid receptor (MR) antagonist improved cardiac and skeletal muscle function and pathology in a mouse model of Duchenne muscular dystrophy. MR is present in limb and respiratory skeletal muscles and functions as a steroid hormone receptor.. The goals of the current study were to compare the efficacy of the specific MR antagonist eplerenone with the non-specific MR antagonist spironolactone, both in combination with the angiotensin-converting enzyme inhibitor lisinopril.. Three groups of n=18 dystrophin-deficient, utrophin-haploinsufficient male mice were given chow containing: lisinopril plus spironolactone, lisinopril plus eplerenone, or no drug, from four to 20 weeks-of-age. Eighteen C57BL/10 male mice were used as wild-type controls.. Treatment with specific and non-specific MR antagonists did not result in any adverse effects to dystrophic skeletal muscles or heart. Both treatments resulted in similar functional and pathological improvements across a wide array of parameters. MR protein levels were not reduced by treatment.. These data suggest that spironolactone and eplerenone show similar effects in dystrophic mice and support the clinical development of MR antagonists for treating skeletal muscles in Duchenne muscular dystrophy.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Disease Models, Animal; Eplerenone; Gene Knockdown Techniques; Heart; Lisinopril; Male; Mice; Mice, Inbred mdx; Mineralocorticoid Receptor Antagonists; Muscle, Skeletal; Muscular Dystrophy, Animal; Myocardium; Spironolactone; Treatment Outcome; Utrophin

The fact that mineralocorticoid receptor antagonists reduce structural and functional alterations induced by cyclosporine A (CsA) indicates that aldosterone plays a key role in chronic CsA nephrotoxicity. We and other researchers have reported local renal aldosterone synthesis. To investigate local renal aldosterone's role in chronic CsA nephrotoxicity, we evaluated the effect of eplerenone (Epl) on renal structural damage and renal dysfunction in adrenalectomized (ADX) rats, and assessed whether the therapeutic benefit was associated with reduction of transforming growth factor-β1 (TGF-β1), connective tissue growth factor (CTGF), plasminogen activator inhibitor type 1 (PAI-1) and collagen I (COL-I) expression.. Male Sprague-Dawley rats fed a normal-sodium diet were divided in four groups: sham-ADX, ADX, CsA, or Epl. Rats in the ADX, CsA and Epl groups were adrenalectomized first. Aldosterone, sodium and potassium levels in serum and urine were measured on the second day. Two weeks later, vehicle (sham-ADX and ADX group), CsA (25mg/kg/d), or CsA and Epl (100 mg/ kg/d) combination was administrated, respectively. After six weeks, urinary protein, creatinine clearance (Ccr), tubulointerstitial fibrosis (TIF), aldosterone level in kidney, and renal aldosterone synthase CYP11B2, COL-I, TGF-β1, CTGF and PAI-1 gene expression levels were determined.. On the second day after surgery, adrenalectomized rats showed undetectable aldosterone with natriuresis, hyponatremia, decreased urinary potassium excretion and hyperpotassemia. CsA reduced Ccr, induced urinary proteins and up-regulated COL-I, TGF-β1, CTGF and PAI-1 gene expression with a significant development of TIF. Eplerenone administration prevented TIF and COL-I, TGF-β1 and PAI-1 up-regulation but did not improve renal function.. Our results suggest local renal aldosterone is an important mediator of renal injury induced by CsA.

Topics: Adrenalectomy; Aldosterone; Animals; Chronic Disease; Cyclosporine; Cytochrome P-450 CYP11B2; Disease Models, Animal; Electrolytes; Eplerenone; Fibrosis; Kidney; Kidney Diseases; Male; Potassium; Rats, Sprague-Dawley; RNA, Messenger; Sodium; Spironolactone

Therapeutic options to treat Non-alcoholic steatohepatitis (NASH) are limited. Mineralocorticoid receptor (MR) activation could play a role in hepatic fibrogenesis and its modulation could be beneficial for NASH.. To investigate whether eplerenone, a specific MR antagonist, ameliorates liver damage in experimental NASH.. C57bl6 mice were fed a choline-deficient and amino acid-defined (CDAA) diet for 22 weeks with or without eplerenone supplementation. Serum levels of aminotransferases and aldosterone were measured and hepatic steatosis, inflammation and fibrosis scored histologically. Hepatic triglyceride content (HTC) and hepatic mRNA levels of pro-inflammatory pro-fibrotic, oxidative stress-associated genes and of MR were also assessed.. CDAA diet effectively induced fibrotic NASH, and increased the hepatic expression of pro-inflammatory, pro-fibrotic and oxidative stress-associated genes. Hepatic MR mRNA levels significantly correlated with the expression of pro-inflammatory and pro-fibrotic genes and were significantly increased in hepatic stellate cells obtained from CDAA-fed animals. Eplerenone administration was associated to a reduction in histological steatosis and attenuation of liver fibrosis development, which was associated to a significant decrease in the expression of collagen-α1, collagen type III, alpha 1 and Matrix metalloproteinase-2.. The expression of MR correlates with inflammation and fibrosis development in experimental NASH. Specific MR blockade with eplerenone has hepatic anti-steatotic and anti-fibrotic effects. These data identify eplerenone as a potential novel therapy for NASH. Considering its safety and FDA-approved status, human studies are warranted.

Topics: Animals; Biomarkers; Disease Models, Animal; Eplerenone; Liver; Liver Cirrhosis; Male; Mice; Mice, Inbred C57BL; Mineralocorticoid Receptor Antagonists; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Receptors, Mineralocorticoid; Spironolactone

The present study was designed to characterize the pharmacological profile of CS-3150, a novel non-steroidal mineralocorticoid receptor antagonist. In the radioligand-binding assay, CS-3150 inhibited (3)H-aldosterone binding to mineralocorticoid receptor with an IC50 value of 9.4nM, and its potency was superior to that of spironolactone and eplerenone, whose IC50s were 36 and 713nM, respectively. CS-3150 also showed at least 1000-fold higher selectivity for mineralocorticoid receptor over other steroid hormone receptors, glucocorticoid receptor, androgen receptor and progesterone receptor. In the reporter gene assay, CS-3150 inhibited aldosterone-induced transcriptional activation of human mineralocorticoid receptor with an IC50 value of 3.7nM, and its potency was superior to that of spironolactone and eplerenone, whose IC50s were 66 and 970nM, respectively. CS-3150 had no agonistic effect on mineralocorticoid receptor and did not show any antagonistic or agonistic effect on glucocorticoid receptor, androgen receptor and progesterone receptor even at the high concentration of 5μM. In adrenalectomized rats, single oral administration of CS-3150 suppressed aldosterone-induced decrease in urinary Na(+)/K(+) ratio, an index of in vivo mineralocorticoid receptor activation, and this suppressive effect was more potent and longer-lasting than that of spironolactone and eplerenone. Chronic treatment with CS-3150 inhibited blood pressure elevation induced by deoxycorticosterone acetate (DOCA)/salt-loading to rats, and this antihypertensive effect was more potent than that of spironolactone and eplerenone. These findings indicate that CS-3150 is a selective and highly potent mineralocorticoid receptor antagonist with long-lasting oral activity. This agent could be useful for the treatment of hypertension, cardiovascular and renal disorders.

Topics: Administration, Oral; Adrenalectomy; Aldosterone; Animals; Antihypertensive Agents; Binding, Competitive; Blood Pressure; Desoxycorticosterone Acetate; Disease Models, Animal; Dose-Response Relationship, Drug; Eplerenone; Female; HEK293 Cells; Humans; Hypertension; Male; Mineralocorticoid Receptor Antagonists; Potassium; Protein Binding; Pyrroles; Rabbits; Radioligand Assay; Rats, Inbred WKY; Rats, Sprague-Dawley; Receptors, Mineralocorticoid; Sodium; Spironolactone; Sulfones; Transcriptional Activation; Transfection; Urological Agents; Water-Electrolyte Balance

Angiotensin II (Ang II) and aldosterone contribute to hypertension, oxidative stress and cardiovascular damage, but the contributions of aldosterone during Ang II-dependent hypertension are not well defined because of the difficulty to assess each independently. To test the hypothesis that during Ang II infusion, oxidative and nitrosative damage is mediated through both the mineralocorticoid receptor (MR) and angiotensin type 1 receptor (AT1), five groups of Sprague-Dawley rats were studied: (i) control; (ii) Ang II infused (80 ng/min × 28 days); (iii) Ang II + AT1 receptor blocker (ARB; 10 mg losartan/kg per day × 21 days); (iv) Ang II + mineralocorticoid receptor (MR) antagonist (Epl; 100 mg eplerenone/day × 21 days); and (v) Ang II + ARB + Epl (Combo; × 21 days). Both ARB and combination treatments completely alleviated the Ang II-induced hypertension, whereas eplerenone treatment only prolonged the onset of the hypertension. Eplerenone treatment exacerbated the Ang II-mediated increase in plasma and heart aldosterone 2.3- and 1.8-fold, respectively, while ARB treatment reduced both. Chronic MR blockade was sufficient to ameliorate the AT1-mediated increase in oxidative damage. All treatments normalized protein oxidation (nitrotyrosine) levels; however, only ARB and Combo treatments completely reduced lipid peroxidation (4-hydroxynonenal) to control levels. Collectively, these data suggest that receptor signalling, and not the elevated arterial blood pressure, is the principal culprit in the oxidative stress-associated cardiovascular damage in Ang II-dependent hypertension.

Topics: Adrenal Glands; Aldehydes; Angiotensin II; Angiotensin II Type 1 Receptor Blockers; Animals; Biomarkers; Blood Pressure; Disease Models, Animal; Drug Therapy, Combination; Eplerenone; Heart Diseases; Hypertension; Lipid Peroxidation; Losartan; Male; Mineralocorticoid Receptor Antagonists; Myocardium; Oxidative Stress; Rats, Sprague-Dawley; Renin-Angiotensin System; Signal Transduction; Spironolactone; Time Factors; Tyrosine

Mineralocorticoid receptor(MR) antagonism reduces sudden cardiac death in heart failure, but the underlying mechanism remains poorly understood. Concurrent treatment with an MR antagonist during rapid ventricular pacing (RVP) prevents development of adverse ventricular electrophysiological remodeling, interstitial fibrosis, inflammatory cytokine gene activation, and ventricular tachyarrhythmia inducibility without diminishing the extent of systolic dysfunction. We hypothesized that attenuating preexistent inflammatory pathways and myocardial fibrosis with eplerenone after systolic heart failure is established by rapid pacing can reduce electrical activation delays and arrhythmia vulnerability.. Dogs subjected to RVP for 8 weeks in the absence or presence of eplerenone treatment during the final 4 weeks of pacing were assessed by echocardiography, electrophysiology study,ventricular fibrosis measurements, and inflammatory cytokine mRNA expression analysis. Eplerenone reversed preexistent ventricular activation delays, interstitial fibrosis, inflammatory cytokine (interleukin-6, tumor necrosis factor-α) gene overexpression, and arrhythmia vulnerability in ventricular paced dogs with heart failure. Eplerenone failed to improve left ventricular systolic dysfunction or chamber enlargement. A correlation between severity of fibrosis and ventricular arrhythmia inducibility was found.. MR antagonism regresses rapid pacing-induced electrical delays, inflammatory cytokine gene activation, and fibrosis in heart failure. Ventricular arrhythmia vulnerability in heart failure is correlated with extent of fibrosis and electrical activation delays during premature excitation.

Topics: Action Potentials; Animals; Anti-Inflammatory Agents; Arrhythmias, Cardiac; Cardiac Pacing, Artificial; Cardiovascular Agents; Disease Models, Animal; Dogs; Eplerenone; Fibrosis; Heart Failure; Hypertrophy, Left Ventricular; Inflammation Mediators; Interleukin-6; Male; Mineralocorticoid Receptor Antagonists; Myocardium; Spironolactone; Time Factors; Tumor Necrosis Factor-alpha; Ventricular Dysfunction, Left; Ventricular Function, Left; Ventricular Remodeling

Pharmacological blockade of the mineralocorticoid receptor (MR) ameliorates end-organ damage in chronic heart failure. However, the clinical use of available steroidal MR antagonists is restricted because of concomitant hyperkalemia especially in patients with diminished kidney function. We have recently identified a novel nonsteroidal MR antagonist, finerenone, which uniquely combines potency and selectivity toward MR. Here, we investigated the tissue distribution and chronic cardiorenal end-organ protection of finerenone in comparison to the steroidal MR antagonist, eplerenone, in 2 different preclinical rat disease models. Quantitative whole-body autoradiography revealed that [C]-labeled finerenone equally distributes into rat cardiac and renal tissues. Finerenone treatment prevented deoxycorticosterone acetate-/salt-challenged rats from functional as well as structural heart and kidney damage at dosages not reducing systemic blood pressure. Finerenone reduced cardiac hypertrophy, plasma prohormone of brain natriuretic peptide, and proteinuria more efficiently than eplerenone when comparing equinatriuretic doses. In rats that developed chronic heart failure after coronary artery ligation, finerenone (1 mg·kg·d), but not eplerenone (100 mg·kg·d) improved systolic and diastolic left ventricular function and reduced plasma prohormone of brain natriuretic peptide levels. We conclude that finerenone may offer end-organ protection with a reduced risk of electrolyte disturbances.

Topics: Animals; Autoradiography; Cardiomegaly; Disease Models, Animal; Eplerenone; Heart Failure; Kidney Diseases; Male; Mineralocorticoid Receptor Antagonists; Naphthyridines; Natriuretic Peptide, Brain; Peptide Fragments; Rats; Rats, Sprague-Dawley; Rats, Wistar; Spironolactone; Tissue Distribution

Localized inflammation of lumbar dorsal root ganglia (DRG) may contribute to low back pain. Local injections of corticosteroids used for low back pain are sometimes ineffective. Many corticosteroids activate not only the target glucocorticoid receptor (GR) but also the mineralocorticoid receptor (MR), which may have proinflammatory effects countering the effects of GR activation.. A low back pain model was implemented in rats (n = 6 to 10 per group) by locally inflaming the L5 DRG. Sensory neuron excitability and mechanical hypersensitivity of the hind paws were measured. Tested steroids were applied locally to the inflamed DRG or orally.. The selective MR blocker eplerenone reduced pain behaviors when given orally starting at the time of surgery, or starting 7 days later. The highly GR-selective agonist fluticasone, applied locally to the inflamed DRG, was much more effective in reducing mechanical hypersensitivity. The MR/GR agonist 6-α methylprednisolone, commonly injected for low back pain, reduced mechanical hypersensitivity when applied locally to the DRG but was less effective than fluticasone. Its effectiveness was improved by combining it with local eplerenone. All tested steroids reduced hyperexcitability of myelinated sensory neurons (n = 71 to 220 cells per group) after inflammation, particularly abnormal spontaneous activity.. This preclinical study indicates the MR may play an important role in low back pain involving inflammation. Some MR effects may occur at the level of the sensory neuron. It may be useful to consider the action of clinically used steroids at the MR as well as at the GR.

Topics: Androstadienes; Animals; Disease Models, Animal; Eplerenone; Fluticasone; Ganglia, Spinal; Inflammation; Low Back Pain; Methylprednisolone; Mineralocorticoid Receptor Antagonists; Rats; Rats, Sprague-Dawley; Receptors, Mineralocorticoid; Spironolactone

The endocrine balance between atrial natriuretic peptide (ANP) and the renin-angiotensin-aldosterone system is critical for the maintenance of arterial blood pressure and volume homeostasis. This study investigated whether a cardiac imbalance between ANP and aldosterone, toward increased mineralocorticoid receptor (MR) signaling, contributes to adverse left ventricular remodeling in response to pressure overload.. We used the MR-selective antagonist eplerenone to test the role of MRs in mediating pressure overload-induced dilatative cardiomyopathy of mice with abolished local, cardiac ANP activity. In response to 21 days of transverse aortic constriction, mice with cardiomyocyte-restricted inactivation (knockout) of the ANP receptor (guanylyl cyclase [GC]-A) or the downstream cGMP-dependent protein kinase I developed enhanced left ventricular hypertrophy and fibrosis together with contractile dysfunction. Treatment with eplerenone (100 mg/kg/d) attenuated left ventricular hypertrophy and fully prevented fibrosis, dilatation, and failure. Transverse aortic constriction induced the cardiac expression of profibrotic connective tissue growth factor and attenuated the expression of SERCA2a (sarcoplasmic reticulum Ca(2+)-ATPase) in knockout mice, but not in controls. These genotype-dependent molecular changes were similarly prevented by eplerenone. ANP attenuated the aldosterone-induced nuclear translocation of MRs via GC-A/cGMP-dependent protein kinase I in transfected HEK 293 (human embryonic kidney) cells. Coimmunoprecipitation and fluorescence resonance energy transfer experiments demonstrated that a population of MRs were membrane associated in close interaction with GC-A and cGMP-dependent protein kinase I and, moreover, that aldosterone caused a conformational change of this membrane MR/GC-A protein complex which was prevented by ANP.. ANP counter-regulates cardiac MR activation in hypertensive heart disease. An imbalance in cardiac ANP/GC-A (inhibition) and aldosterone/MR signaling (augmentation) favors adverse cardiac remodeling in chronic pressure overload.

Topics: Animals; Atrial Natriuretic Factor; Blotting, Western; Cardiomyopathy, Dilated; Connective Tissue Growth Factor; Disease Models, Animal; DNA; Eplerenone; Gene Expression Regulation; HEK293 Cells; Humans; Immunohistochemistry; Mice; Mice, Knockout; Microscopy, Confocal; Mineralocorticoid Receptor Antagonists; Myocytes, Cardiac; Receptors, Mineralocorticoid; Reverse Transcriptase Polymerase Chain Reaction; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Signal Transduction; Spironolactone; Ventricular Remodeling

After myocardial infarction (post-MI), inflammation and apoptosis contribute to progressive cardiac remodeling and dysfunction. Cardiac mineralocorticoid receptor (MR) and β-adrenergic signaling promote apoptosis and inflammation. Post-MI, MR activation in the brain contributes to sympathetic hyperactivity and an increase in cardiac aldosterone. In the present study, we assessed the time course of macrophage infiltration and apoptosis in the heart as detected by both terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and active caspase-3 immunostaining in both myocytes and nonmyocytes, as well as the effects of central MR blockade by intracerebroventricular infusion of eplerenone at 5 μg/day on peak changes in macrophage infiltration and apoptosis post-MI. Macrophage numbers were markedly increased in the infarct and peri-infarct zones and to a minor extent in the noninfarct part of the left ventricle at 10 days post-MI and decreased over the 3-mo study period. Apoptosis of both myocytes and nonmyocytes was clearly apparent in the infarct and peri-infarct areas at 10 days post-MI. For TUNEL, the increases persisted at 4 and 12 wk, but the number of active caspase-3-positive cells markedly decreased. Central MR blockade significantly decreased CD80-positive proinflammatory M1 macrophages and increased CD163-positive anti-inflammatory M2 macrophages in the infarct. Central MR blockade also reduced apoptosis of myocytes by 40-50% in the peri-infarct and to a lesser extent of nonmyocytes in the peri-infarct and infarct zones. These findings indicate that MR activation in the brain enhances apoptosis both in myocytes and nonmyocytes in the peri-infarct and infarct area post-MI and contributes to the inflammatory response.

Topics: Aldosterone; Animals; Apoptosis; Caspase 3; Disease Models, Animal; Eplerenone; Macrophages; Male; Myocardial Infarction; Rats, Wistar; Receptors, Mineralocorticoid; Spironolactone; Ventricular Remodeling

A chronic increase in circulating angiotensin II (Ang II) activates an aldosterone-mineralocorticoid receptor-ouabain neuromodulatory pathway in the brain that increases neuronal activation in hypothalamic nuclei, such as the paraventricular nucleus (PVN) and causes progressive hypertension. Several models of chronic sympathetic hyperactivity are associated with an increase in AT1 and glutamate receptor activation in the PVN. The current study evaluated whether increased angiotensin type 1 (AT1) and glutamate receptor-dependent signaling in the PVN contributes to the maintenance of blood pressure (BP) in Ang II-hypertensive Wistar rats, and the role of aldosterone-mineralocorticoid receptor pathway in this enhanced signaling. After subcutaneous infusion of Ang II for 2 weeks, in conscious rats BP and heart rate were recorded after (1) 10-minute bilateral infusions of candesartan and kynurenate in the PVN; (2) 1 hour intracerebroventricular infusion of eplerenone, and (3) candesartan and kynurenate after eplerenone. Candesartan or kynurenate in the PVN fully reversed the increase in BP from circulating Ang II. Kynurenate after candesartan or candesartan after kynurenate did not further lower BP. Intracerebroventricular infusion of eplerenone at 16 hours after its infusion fully reversed the increase in BP from circulating Ang II. After eplerenone, candesartan and kynurenate in the PVN did not further decrease BP. These findings suggest that increased mineralocorticoid receptor activation in the brain activates a slow neuromodulatory pathway that maintains enhanced AT1 and glutamate receptor-dependent signaling in the PVN, and thereby the hypertension from a chronic increase in circulating Ang II.

Topics: Angiotensin II; Angiotensin II Type 1 Receptor Blockers; Animals; Benzimidazoles; Biphenyl Compounds; Blood Pressure; Disease Models, Animal; Eplerenone; Glutamic Acid; Heart Rate; Hypertension; Infusions, Intravenous; Infusions, Intraventricular; Kynurenic Acid; Male; Mineralocorticoid Receptor Antagonists; Paraventricular Hypothalamic Nucleus; Rats; Rats, Wistar; Receptor, Angiotensin, Type 1; Receptors, Glutamate; Receptors, Mineralocorticoid; Signal Transduction; Spironolactone; Tetrazoles

Obesity, diabetes, fatty liver, and hypertension are major determinants of the metabolic syndrome. The effects of aldosterone and mineralocorticoid receptor blockers on fatty liver are largely unknown. The aim of the present study was to evaluate the relationships between aldosterone and the development of fatty liver.. In our experiments, we performed adrenalectomy (ADX) or administered 100 mg/kg/day eplerenone, a specific mineralocorticoid receptor blocker, to male C57BL/6 mice fed with a 60% fat diet for 20 weeks.. High-fat diet led to metabolic syndrome as indicated by increased body weight, elevated systolic blood pressure, impaired glucose tolerance, elevated insulin levels, and development of fatty liver. A marked reduction of aldosterone by ADX or blockade of aldosterone interaction with its receptor by eplerenone, which increased serum aldosterone considerably, resulted in reduced blood pressure, and reduced serum insulin and levels of triglycerides. However, differential effects were found on reduction of blood glucose to normal levels, which was observed only in ADX. Neither ADX nor eplerenone affected fatty liver formation or body weight. In cultured hepatocytes, triglyceride loading induced by high glucose, oleic acid or very low density lipoprotein was not affected by aldosterone, spironolactone or eplerenone.. Our results suggest that whereas aldosterone might be involved in some of the diet-induced insulin and glucose metabolic effects, it played no role in the development of fatty liver.

Topics: Adrenalectomy; Aldosterone; Animals; Blood Glucose; Blood Pressure; Cells, Cultured; Cholesterol; Diet, High-Fat; Disease Models, Animal; Eplerenone; Fatty Liver; Hepatocytes; Insulin; Insulin Resistance; Lipoproteins, VLDL; Liver; Male; Metabolic Syndrome; Mice; Mice, Inbred C57BL; Mineralocorticoid Receptor Antagonists; Oleic Acid; Spironolactone; Triglycerides; Weight Gain

Elevated plasma aldosterone concentrations in patients have been linked to a spectrum of cardiovascular diseases. Mineralocorticoid receptor antagonists provide additional benefits in patients with heart failure. However, whether aldosterone and the mineralocorticoid receptor are involved in aortic aneurysm is unknown.. We report that administration of deoxycorticosterone acetate (DOCA) and salt or aldosterone and salt, but not DOCA or salt alone, to C57BL/6 male mice induced abdominal and thoracic aortic aneurysm formation and rupture in an age-dependent manner. DOCA and salt- or aldosterone and salt-induced aortic aneurysm mimicked human aortic aneurysm with respect to elastin degradation, inflammatory cell infiltration, smooth muscle cell degeneration and apoptosis, and oxidative stress. Aortic aneurysm formation did not correlate with the increase in blood pressure induced by DOCA and salt. Systemic administration of the angiotensin-converting enzyme inhibitor, enalapril, or angiotensin type 1 receptor antagonist, losartan, did not affect DOCA and salt-induced aortic aneurysm. In contrast, the mineralocorticoid receptor antagonists, spironolactone or eplerenone, significantly attenuated DOCA and salt- or aldosterone and salt-induced aortic aneurysm.. The current study describes a novel aortic aneurysm animal model induced by mineralocorticoid receptor agonist and high salt, and reveals a previously unrecognized but potentially significant role of aldosterone in the pathogenesis of aortic aneurysm. These findings imply that mineralocorticoid receptor antagonists may be effective in the treatment of some aortic aneurysms.

Topics: Aldosterone; Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Animals; Aorta; Aortic Aneurysm, Abdominal; Aortic Aneurysm, Thoracic; Aortic Rupture; Apoptosis; Blood Pressure; Desoxycorticosterone; Disease Models, Animal; Elastin; Enalapril; Eplerenone; Losartan; Male; Mice; Mice, Inbred C57BL; Mineralocorticoid Receptor Antagonists; Muscle, Smooth, Vascular; Oxidative Stress; Receptors, Mineralocorticoid; Sodium Chloride, Dietary; Spironolactone; Time Factors

The optimal medical management to delay the progression of aortic aneurysms has not been fully clarified, and the only standard treatment at present is antihypertensive therapy. Previous studies have shown beneficial effects of selective mineralocorticoid receptor (MR) antagonists on cardiovascular remodeling. The aim of the present study was to investigate the effect of a selective MR antagonist on aortic aneurysm progression.. Seven-week-old C57BL/6J male mice were administered with angiotensin II and β-aminopropionitrile for 4 weeks. The mice received either vehicle or eplerenone, a selective MR antagonist (100 mg/kg daily) every day by gavage, starting at 7 weeks of age. The production of inflammatory cytokines in cultures of high mobility group box-1-stimulated macrophages with or without a MR antagonist was also analyzed using an enzyme-linked immunosorbent assay.. Although no differences were found in the peak systolic blood pressure between the experimental groups, the mice in the eplerenone group showed a significant reduction in aneurysm development. On histologic analysis, coarse and stretched elastic fibers were markedly improved in the aortic wall in the eplerenone group. Real-time polymerase chain reaction of both aortic wall and perivascular adipose tissue demonstrated the expression of tumor necrosis factor-α, interleukin-6, and matrix metalloproteinase-2 was significantly decreased in eplerenone group, and that of monocyte chemoattractant protein-1 in the aortic wall was also significantly decreased. Macrophage infiltration in the aortic wall and perivascular adipose tissue in the eplerenone group was also significantly decreased. The production of tumor necrosis factor-α and interleukin-6 in macrophage culture, which was stimulated by high mobility group box-1 and CpG oligodeoxynucleotides, was also significantly decreased in the eplerenone group.. Eprelenone suppressed aortic aneurysm progression through an anti-inflammatory effect. Thus, selective MR antagonists might be effective in preventing the progression of aortic aneurysms.

Topics: Animals; Aortic Aneurysm; Blood Pressure; Chemokine CCL2; Disease Models, Animal; Disease Progression; Eplerenone; Gene Expression; Interleukin-6; Macrophages; Male; Mice; Mice, Inbred C57BL; Mineralocorticoid Receptor Antagonists; Spironolactone; Tumor Necrosis Factor-alpha; Vasculitis

Right ventricular (RV) failure due to increased pressure load causes significant morbidity and mortality in patients with congenital heart diseases and pulmonary arterial hypertension. It is unknown whether renin-angiotensin-aldosterone-system (RAAS) inhibition (the cornerstone of left ventricular failure treatment) is effective in RV failure. We investigated the effects of combination treatment of aldosterone-blocker eplerenone+angiotensin II receptor blocker losartan (Ep/Lo) on RV remodeling and function in a model of RV failure due to increased pressure load.. Rats (n=48) were randomized for pulmonary artery banding (PAB) or sham surgery and for losartan (20 mg/kg/d)+eplerenone (100 mg/kg/d) treatment (Ep/Lo) or vehicle (VEH). RV function was assessed by echocardiography and pressure-volume analysis at 5 and 11 weeks, or at the occurrence of clinical RV failure symptoms necessitating termination. PAB resulted in RV failure in all rats, as defined by reduced cardiac output, RV stroke volume, increased RV end diastolic pressure and liver congestion as well as RV fibrosis, hypertrophy and reduced capillary density. Clinical RV failure necessitated termination in 5/12 PAB-VEH rats. Angiotensin II type 1-receptor expression in the RV was reduced in PAB rats indicating local RAAS activation. Treatment of PAB rats with Ep/Lo significantly lowered arterial pressures, but had no significant effect on RV function, remodeling or survival compared to PAB-VEH rats.. RAAS inhibition does not beneficially affect experimental RV failure due to chronic pressure load. This is of high clinical relevance, because it indicates that the RV response to RAAS inhibition might fundamentally differ from that of the LV.

Topics: Animals; Disease Models, Animal; Drug Therapy, Combination; Eplerenone; Heart Failure; Losartan; Male; Random Allocation; Rats; Rats, Wistar; Spironolactone; Treatment Outcome; Ventricular Dysfunction, Right

Cardiac steatosis and apoptosis are key processes in diabetic cardiomyopathy, but the underlying mechanisms have not been elucidated, leading to a lack of effective therapy. The mineralocorticoid receptor blocker, eplerenone, has demonstrated anti-fibrotic actions in the diabetic heart. However, its effects on the fatty-acid accumulation and apoptotic responses have not been revealed.. Non-hypertensive Zucker Diabetic Fatty (ZDF) rats received eplerenone (25 mg/kg) or vehicle. Zucker Lean (ZL) rats were used as control (n = 10, each group). After 16 weeks, cardiac structure and function was examined, and plasma and hearts were isolated for biochemical and histological approaches. Cultured cardiomyocytes were used for in vitro assays to determine the direct effects of eplerenone on high fatty acid and high glucose exposed cells.. In contrast to ZL, ZDF rats exhibited hyperglycemia, hyperlipidemia, insulin-resistance, cardiac steatosis and diastolic dysfunction. The ZDF myocardium also showed increased mitochondrial oxidation and apoptosis. Importantly, eplerenone mitigated these events without altering hyperglycemia. In cultured cardiomyocytes, high-concentrations of palmitate stimulated the fatty-acid uptake (in detriment of glucose assimilation), accumulation of lipid metabolites, mitochondrial dysfunction, and apoptosis. Interestingly, fatty-acid uptake, ceramides formation and apoptosis were also significantly ameliorated by eplerenone.. By blocking mineralocorticoid receptors, eplerenone may attenuate cardiac steatosis and apoptosis, and subsequent remodelling and diastolic dysfunction in obese/type-II diabetic rats.

Topics: Animals; Apoptosis; Cardiomegaly; Cell Line; Diabetes Mellitus, Type 2; Diabetic Cardiomyopathies; Diastole; Disease Models, Animal; Eplerenone; Fatty Acids; Fibrosis; Glucose; Hyperlipidemias; Lipid Metabolism; Male; Mineralocorticoid Receptor Antagonists; Mitochondria, Heart; Myocardium; Myocytes, Cardiac; Rats; Rats, Zucker; Spironolactone; Time Factors; Ventricular Dysfunction; Ventricular Function; Ventricular Remodeling

Prolonged elevation of serum aldosterone leads to renal fibrosis. Inflammation also plays a role in the pathogenesis of renal disease. We used a rat model of interstitial renal fibrosis to test the hypothesis that eplerenone-mediated aldosterone blockade prevents renal fibrosis due to its anti-inflammatory and anti-proliferative effects.. Eplerenone (a selective aldosterone blocker) or vehicle (control), was given to male Wistar rats (50 mg/kg, twice daily) for 7 days before unilateral ureteral obstruction (UUO) and for an additional 28 days after surgery. Body weight, blood pressure, renal histo-morphology, immune-staining for macrophages, monocyte chemotactic protein-1, proliferating cell nuclear antigen, α-smooth muscle actin, and serum and urine markers of renal function and oxidative stress were determined for both groups on 7, 14, and 28 days after surgery.. Epleronone had no effect on body weight or blood pressure. However, eplerenone inhibited the development of renal fibrosis, inflammation (macrophage and monocyte infiltration), interstitial cell proliferation, and activation of interstitial cells (α-SMA expression). Epleronone also reduced oxidative stress.. The anti-fibrotic effect of eplerenone appears to be unrelated to its effect on blood pressure. Eplerenone inhibits renal inflammation, interstitial cell proliferation, phenotypic changes of interstitial cells, and reduces oxidative stress.

Topics: Animals; Cell Proliferation; Disease Models, Animal; Eplerenone; Fibrosis; Inflammation; Male; Mineralocorticoid Receptor Antagonists; Nephritis, Interstitial; Oxidative Stress; Random Allocation; Rats; Rats, Wistar; Spironolactone

Increase in cerebrospinal fluid (CSF) Na(+) concentration ([Na(+)]) precedes hypertension and is a key step in the development of salt-induced hypertension. In the choroid plexus (CP), epithelial Na(+) channels (ENaCs) have an important role in Na(+) transport from the blood into the CSF. However, it remains unknown whether the mineralocorticoid receptors (MR)/ENaCs pathway in the CP of stroke-prone spontaneously hypertensive rats (SHRSP) is involved in neural mechanisms of hypertension. Therefore, we examined the role of the MR/ENaCs pathway in the CP in the development of hypertension in SHRSP associated with an increase in CSF [Na(+)]. As a marker of MR activation, serum/glucocorticoid-inducible kinase 1 (Sgk1) expression levels in the CP were measured and found to be greater in SHRSP than in Wistar-Kyoto (WKY) rats. CSF [Na(+)] levels were also higher in SHRSP than in WKY rats. In SHRSP, high-salt intake (8%) increased blood pressure and urinary norepinephrine excretion compared with those in animals fed a regular salt diet (0.5%) for 2 weeks. Furthermore, the expression levels of MR, Sgk1 and ENaCs in the CP and the increase in CSF [Na(+)] were greater in SHRSP fed a high-salt diet than in those fed a regular salt diet. These alterations were attenuated by intracerebroventricular infusion of eplerenone (10 μg kg(-1) per day), except for α-ENaC and β-ENaC. We conclude that activation of the MR/ENaCs pathway in the CP contributes to hypertension via an increase in CSF [Na(+)], thereby exaggerating salt-induced hypertension with sympathetic hyperactivation in SHRSP.

Topics: Animals; Blood Pressure; Choroid Plexus; Disease Models, Animal; Epithelial Sodium Channels; Eplerenone; Hypertension; Immediate-Early Proteins; Male; Mineralocorticoid Receptor Antagonists; Protein Serine-Threonine Kinases; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptors, Mineralocorticoid; Risk Factors; Signal Transduction; Sodium; Sodium Chloride, Dietary; Spironolactone; Stroke

Experiments with hyperaldosteronemic animals suggest that, despite lowering plasma aldosterone, salt worsens renal injury by paradoxical activation of the mineralocorticoid receptor (MR). Salt and aldosterone synergistically contribute to renal impairment through Rac1-mediated activation of the MR, but whether angiotensin II also promotes renal injury through this mechanism is unknown. Here, we placed angiotensin II-overproducing double transgenic Tsukuba hypertensive mice on a low- or high-salt intake for 6 weeks and treated some animals with adrenalectomy, the MR antagonist eplerenone, the Rac inhibitor EHT1864, or hydralazine. High-salt intake, but not low-salt intake, led to hypertension and prominent kidney injury. Adrenalectomy prevented angiotensin II/salt-induced nephropathy in mice receiving high-salt intake, which was recapitulated by aldosterone supplementation, suggesting the involvement of aldosterone/MR signaling. Plasma aldosterone levels, however, were lower in high- than low-salt conditions. Instead, angiotensin II/salt-evoked MR activation associated with Rac1 activation and was not dependent on plasma aldosterone level. Both EHT1864 and eplerenone repressed the augmented MR signaling and mitigated kidney injury with partial but significant reduction in BP with high-salt intake. Hydralazine similarly reduced BP, but it neither suppressed the Rac1-MR pathway nor ameliorated the nephropathy. Taken together, these results show that angiotensin II and salt accelerate kidney injury through Rac1-mediated MR activation. Rac inhibition may be a promising strategy for the treatment of CKD.

Topics: Acute Kidney Injury; Adrenalectomy; Aldosterone; Analysis of Variance; Angiotensin II; Animals; Blotting, Western; Disease Models, Animal; Eplerenone; Immunohistochemistry; Male; Mice; Mice, Inbred Strains; rac1 GTP-Binding Protein; Random Allocation; Real-Time Polymerase Chain Reaction; Receptors, Mineralocorticoid; Signal Transduction; Sodium Chloride, Dietary; Spironolactone; Statistics, Nonparametric

The beneficial effects of eplerenone, a specific mineralocorticoid receptor blocker, were previously demonstrated in early atherosclerosis (ATS). The aim of the present study was to evaluate the effect of eplerenone in advanced versus early ATS. Apolipoprotein E knockout mice aged 16 or 32 weeks were randomly divided into eplerenone (100 mg·kg·d) or vehicle treatment for 14 weeks. Eplerenone reduced atherosclerotic lesion size by 51% only in early ATS. In peritoneal macrophages obtained from these mice, eplerenone reduced messenger RNA expression of pro-inflammatory markers, interleukin 6, tumor necrosis factor α, monocyte chemotactic protein 1, and increased anti-inflammatory marker arginase 1 to a greater extent in early compared with advanced ATS. These changes correspond to macrophage polarization toward alternative inflammatory phenotype. Messenger RNA expression of the mineralocorticoid receptor and aldosterone synthase were also reduced by eplerenone to a greater extent in early ATS, and these might increase the sensitivity of macrophages to mineralocorticoid blockade in early ATS. The results of the present study point to the benefits of early initiation of treatment with eplerenone in reducing experimental ATS.

Topics: Animals; Aorta, Thoracic; Aortic Diseases; Apolipoproteins E; Atherosclerosis; Cytochrome P-450 CYP11B2; Cytokines; Disease Models, Animal; Disease Progression; Eplerenone; Inflammation Mediators; Lipids; Macrophages, Peritoneal; Male; Mice; Mice, Knockout; Mineralocorticoid Receptor Antagonists; Plaque, Atherosclerotic; Receptors, Mineralocorticoid; RNA, Messenger; Spironolactone

Mineralocorticoid receptor (MR) antagonists have protective effects in the brain during experimental ischemic stroke, and we have previously demonstrated a key role for myeloid MR during stroke pathogenesis. In this study, we explore both model- and sex-specific actions of myeloid MR during ischemic stroke.. The MR antagonist eplerenone significantly reduced the infarct size in male (control, 99.5 mm(3); eplerenone, 74.2 mm(3); n=8 to 12 per group) but not female (control, 84.0 mm(3); eplerenone, 83.7 mm(3); n=6 to 7 per group) mice after transient (90-minute) middle cerebral artery occlusion. In contrast to MR antagonism, genetic ablation of myeloid MR in female mice significantly reduced infarct size (myeloid MR knockout, 9.4 mm(3) [5.4 to 36.6]; control, 66.0 mm(3) [50.0 to 81.4]; n=6 per group) after transient middle cerebral artery occlusion. This was accompanied by reductions in inflammatory gene expression and improvement in neurological function. In contrast to ischemia-reperfusion, myeloid MR-knockout mice were not protected from permanent middle cerebral artery occlusion. The infarct size and inflammatory response after permanent occlusion showed no evidence of protection by myeloid MR knockout in photothrombotic and intraluminal filament models of permanent occlusion.. These studies demonstrate that MR antagonism is protective in male but not female mice during transient middle cerebral artery occlusion, whereas genetic ablation of myeloid MR is protective in both male and female mice. They also highlight important mechanistic differences in the role of myeloid cells in different models of stroke and confirm that specific myeloid phenotypes play key roles in stroke protection.

Topics: Animals; Brain Ischemia; Disease Models, Animal; Eplerenone; Female; Gene Expression Profiling; Immunohistochemistry; Infarction, Middle Cerebral Artery; Male; Mice; Mice, Knockout; Mineralocorticoid Receptor Antagonists; Receptors, Mineralocorticoid; Spironolactone; Stroke

We investigated the effects of chronic mineralocorticoid receptor blockade with eplerenone on the development and progression of hypertension and end organ damage in Dahl salt-sensitive rats. Eplerenone significantly attenuated the progressive rise in systolic blood pressure (SBP) (204 ± 3 vs. 179±3 mmHg, p < 0.05), reduced proteinuria (605.5 ± 29.6 vs. 479.7 ± 26.1 mg/24h, p < 0.05), improved injury scores of glomeruli, tubules, renal interstitium, and vasculature in Dahl salt-sensitive rats fed a high-salt diet. These results demonstrate that mineralocorticoid receptor antagonism provides target organ protection and attenuates the development of elevated blood pressure (BP) in a model of salt-sensitive hypertension.

Topics: Aldosterone; Animals; Blood Pressure; Chronic Disease; Creatinine; Disease Models, Animal; Disease Progression; Electrolytes; Eplerenone; Heart Rate; Hypertension, Renal; Kidney; Male; Mineralocorticoid Receptor Antagonists; Organ Size; Rats; Rats, Inbred Dahl; Receptors, Mineralocorticoid; Sodium Chloride, Dietary; Spironolactone

Myocardial fibrosis increases arrhythmia vulnerability of the diseased heart. The renin-angiotensin-aldosterone system (RAAS) governs myocardial collagen synthesis. We hypothesized that reducing cardiac fibrosis by chronic RAAS inhibition would result in reduced arrhythmia vulnerability of the senescent mouse heart. Wild-type mice (52 wk old) were treated for 36 wk: 1) untreated control (C); 2) eplerenone (E); 3) losartan (L); and 4) cotreatment with eplerenone and losartan (EL). Ventricular epicardial activation mapping was performed on Langendorff-perfused hearts. Arrhythmia inducibility was tested by one to three premature stimuli and burst pacing. Longitudinal and transverse conduction velocity and dispersion of conduction were determined during pacing at a basic cycle length of 150 ms. Sirius red staining (collagen) was performed. As a result, in the RV of mice in the E, L, and EL groups, transverse conduction velocity was significantly increased and anisotropic ratio was significantly decreased compared with those values of mice in the C group. Anisotropic reentrant arrhythmias were induced in 52% of untreated mice and significantly reduced to 22%, 26%, and 16% in the E, L, and EL groups, respectively. Interstitial fibrosis was significantly decreased in both the RV and LV of all treated groups. Scattered patches of replacement fibrosis were found in 90% of untreated hearts, which were significantly reduced in the E, L, and EL groups. A strong correlation between the abundance of patchy fibrosis and arrhythmia inducibility was found. In conclusion, chronic RAAS inhibition limited aging-related interstitial fibrosis. The lower arrhythmogeneity of treated mice was directly correlated to the reduced amount of patchy fibrosis.

Topics: Age Factors; Aging; Angiotensin II Type 1 Receptor Blockers; Animals; Arrhythmias, Cardiac; Blood Pressure; Cardiac Pacing, Artificial; Cell Communication; Cellular Senescence; Connexin 43; Disease Models, Animal; Echocardiography, Doppler; Electrocardiography; Epicardial Mapping; Eplerenone; Female; Fibrosis; Heart Conduction System; Heart Diseases; Losartan; Mice; Mice, Inbred C57BL; Mineralocorticoid Receptor Antagonists; Myocardium; Renin-Angiotensin System; Spironolactone; Ventricular Function, Left; Ventricular Function, Right

Several proteins constituting the slit diaphragm are considered important for maintaining capillary wall permselectivity. Early intervention with blockers of angiotensin II receptors (AR) and mineralocorticoid receptors (MR) is effective against proteinuria in models of chronic hypertensive and protein-induced renal damage. However, the effects of AR and/or MR blockers in a model of acute nephrotic syndrome remain unknown. The effects of AR and MR blockers were examined in puromycin aminonucleoside (PAN)-treated rats.. Six week old male Sprague-Dawley (SD) rats were injected with PAN or vehicle and assigned to groups as follows: vehicle (group C); PAN (group P); PAN followed 3 days later by administration of the MR blocker, eplerenone (group MR), and by the AR blocker, losartan (group AR). Blood pressure and urinary protein excretion were measured and all rats were killed for immunohistochemical investigation on day 14 after PAN administration.. Blood pressure did not change throughout the study period. Proteinuria was decreased in groups MR and AR compared with group P (on day 14 after PAN administration, respectively; group P vs AR, P < 0.01; group P vs MR, P < 0.05). Nephrin, podocin and podocalyxin staining was preserved in the glomeruli of groups MR and AR compared with group P.. The MR and AR blockers decreased proteinuria in the acute model of nephrotic syndrome with preserved expression of glomerular podocyte protein independently of blood pressure.

Topics: Angiotensin II Type 1 Receptor Blockers; Animals; Blood Pressure; Disease Models, Animal; Eplerenone; Fluorescent Antibody Technique; Intracellular Signaling Peptides and Proteins; Losartan; Male; Membrane Proteins; Mineralocorticoid Receptor Antagonists; Nephrosis, Lipoid; Podocytes; Proteinuria; Puromycin Aminonucleoside; Rats; Rats, Sprague-Dawley; Sialoglycoproteins; Spironolactone; Time Factors

Over the past years, the importance of the renin-angiotensin-aldosterone system in atrial fibrillation (AF) pathophysiology has been recognised. Lately, the role of aldosterone in AF pathophysiology and mineralocorticoid receptor (MR) antagonism in "upstream" AF treatment is discussed. Hypothesising that selective MR antagonism might also influence atrial ion currents (L-type calcium current [I (Ca,L)], transient outward potassium current [I (to)], sustained outward potassium current [I (sus)]) and their tachycardia-induced remodelling, the effects of an eplerenone treatment were studied in a rabbit model. Six groups each with four animals were built. Animals of the control group received atrial pacing leads, but in contrast to the pacing groups, no atrial tachypacing (600 per minute for 24 and 120 h immediately before heart removal) was applied. Animals of the eplerenone groups were instrumented/paced as the corresponding control/pacing groups, but were additionally treated with eplerenone (7 days before heart removal). Atrial tachypacing was associated with a reduction of I (Ca,L). I (to) was decreased after 24 h of tachypacing, but returned to control values after 120 h. In the absence of rapid atrial pacing, MR antagonism reduced I (Ca,L) to a similar extent as 120 h of tachypacing alone. Based on this lower "take-off level", I (Ca,L) was not further decreased by high-rate pacing. I (to) and its expected tachycardia-induced alterations were not influenced by MR antagonism. In our experiments, selective MR antagonism influenced atrial I (Ca,L) and its tachycardia-induced alterations. As changes of I (Ca,L) are closely linked with atrial calcium signalling, the relevance of these alterations in AF pathophysiology and, accordingly, AF treatment is likely and has to be further evaluated.

Topics: Animals; Atrial Fibrillation; Calcium Channels, L-Type; Cardiac Pacing, Artificial; Disease Models, Animal; Electric Conductivity; Eplerenone; Female; Heart Atria; Heart Conduction System; Ion Channel Gating; Mineralocorticoid Receptor Antagonists; Potassium Channels; Rabbits; Spironolactone; Tachycardia

Rats with 5/6 nephrectomy have metabolic acidosis with a progressive decline in the glomerular filtration rate (GFR) ameliorated by endothelin and aldosterone antagonists and by dietary alkali. Interestingly, rats with 2/3 nephrectomy have no metabolic acidosis yet have a progressive GFR decline induced by acid retention and ameliorated by dietary alkali. Because patients without metabolic acidosis but with a moderately reduced GFR have a progressive GFR decline, ameliorated by oral sodium bicarbonate, we used rats with 2/3 nephrectomy to model these patients. Kidney acid content, endothelin-1, and aldosterone (measured by microdialysis) were higher in the rats with 2/3 nephrectomy than those with a sham operation despite no differences in plasma acid-base parameters. The GFR of the former but not the latter was lower at 25 than at 1 week after nephrectomy. Endothelin and aldosterone antagonism improved the preservation of GFR; however, this remained lower at week 24 than at week 1. By contrast, the GFR at weeks 24 and 1 was not different if the rats were given dietary alkali to normalize the kidney acid content. Antagonist of endothelin and aldosterone yielded no added GFR benefit. Thus, our study shows that (1) the decline in GFR in 2/3 nephrectomy is mediated by acid retention-induced kidney endothelin and aldosterone production; (2) receptor antagonism and dietary alkali are not additive; and (3) dietary alkali better preserves GFR than both endothelin and aldosterone receptor antagonism.

Topics: Acid-Base Equilibrium; Acidosis; Administration, Oral; Aldosterone; Animals; Bicarbonates; Calcium Gluconate; Dietary Supplements; Disease Models, Animal; Endothelin A Receptor Antagonists; Endothelin-1; Eplerenone; Female; Glomerular Filtration Rate; Kidney; Male; Microdialysis; Mineralocorticoid Receptor Antagonists; Nephrectomy; Phenylpropionates; Pyrimidines; Rats; Rats, Wistar; Receptor, Endothelin A; Renal Insufficiency; Spironolactone; Time Factors

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

Aldosterone blockade reduces sudden cardiac death in heart failure, but the underlying mechanism is unclear.. This study's aim was to determine whether chronic eplerenone treatment protects against detrimental ventricular electrical remodeling and development of an arrhythmogenic substrate in a rapid ventricular pacing (RVP)-induced heart failure model.. Dogs were assigned randomly to oral placebo or eplerenone treatment and divided into 4 groups: 2 sham-operated (no RVP) and 2 RVP groups. After 5 weeks of no RVP or RVP along with concurrent placebo or eplerenone treatment, dogs underwent echocardiographic assessments of systolic function and chamber size and electrophysiologic measurements of ventricular repolarization, refractoriness, conduction, tachyarrhythmia inducibility, and myocardial activation delays after premature stimulation.. Eplerenone failed to prevent left ventricular systolic dysfunction or chamber enlargement in RVP dogs. Eplerenone attenuated prolongation of ventricular repolarization and refractoriness, increases in dispersion of repolarization and refractoriness, fractionation of ventricular electrograms, and delays in myocardial activation after premature stimulation at short coupling intervals and improved arrhythmia vulnerability score in RVP dogs with heart failure. Ventricular tachyarrhythmia inducibility in heart failure dogs was predicted by activation delays after premature stimulation at short coupling intervals, which were prevented by eplerenone. Eplerenone did not alter electrophysiological parameters in no-RVP dogs without heart failure.. Eplerenone attenuates heart failure-related ventricular electrical remodeling and tachyarrhythmia vulnerability. Inhibition of myocardial activation delays during premature excitation may contribute to preventing development of an arrhythmogenic ventricular substrate in heart failure.

Topics: Animals; Disease Models, Animal; Dogs; Electrocardiography; Eplerenone; Heart Failure; Mineralocorticoid Receptor Antagonists; Spironolactone; Tachycardia, Ventricular; Ventricular Remodeling

Salt status plays a pivotal role in angiotensin-II-induced organ damage by regulating reactive oxygen species status, and it is reported that reactive oxygen species activate mineralocorticoid receptors.. To clarify the role of reactive oxygen species-related mineralocorticoid receptor activation in angiotensin-II-induced cardiac dysfunction, we examined the effect of the following: salt status; an MR antagonist, eplerenone; and an antioxidant, tempol in angiotensin-II-loaded Sprague-Dawley rats.. Angiotensin-II/salt-loading elevated blood pressure, and neither eplerenone nor tempol antagonized the rise in blood pressure significantly. Left ventricular diastolic function was monitored by measuring peak velocity of a mitral early inflow (E), the ratio of mitral early inflow to atrial contraction related flow (E/A), deceleration time of mitral early inflow and -dP/dt, the time constant (T), and filling pressure (left ventricular end-diastolic pressure) by echocardiography or cardiac catheterization. Despite the suppressed serum aldosterone, left ventricular diastolic function was deteriorated with angiotensin II/high salt, but not affected by angiotensin II/low salt. However, angiotensin-II/salt-induced cardiac dysfunction was restored by eplerenone and tempol. Nicotinamide adenine dinucleotide phosphateoxidase-derived superoxide formation was greater in the hearts of the angiotensin II/high-salt rats than of the angiotensin II/low-salt rats. The expression of the Na(+) -H(+) exchanger isoform 1, a target of mineralocorticoid receptor activation, was significantly increased in the angiotensin II/high-salt group. Both tempol and eplerenone inhibited the angiotensin-II/salt-induced upregulation of Na(+) -H(+) exchanger isoform 1.. These findings demonstrate that mineralocorticoid receptor activation by oxidative stress can cause left ventricular diastolic dysfunction in a rat model of mild hypertension.

Topics: Angiotensin II; Animals; Antioxidants; Cyclic N-Oxides; Diastole; Disease Models, Animal; Eplerenone; Male; Mineralocorticoid Receptor Antagonists; Oxidative Stress; Rats; Rats, Sprague-Dawley; Receptors, Mineralocorticoid; Sodium Chloride, Dietary; Spin Labels; Spironolactone; Vasoconstrictor Agents; Ventricular Dysfunction, Left

Metabolic syndrome is a highly predisposing condition for cardiovascular disease and could be a cause of excess salt-induced organ damage. Recently, several investigators have demonstrated that salt loading causes left ventricular diastolic dysfunction associated with increased oxidative stress and mineralocorticoid receptor activation. We, therefore, investigated whether excess salt induces cardiac diastolic dysfunction in metabolic syndrome via increased oxidative stress and upregulation of mineralocorticoid receptor signals. Thirteen-week-old spontaneously hypertensive rats and SHR/NDmcr-cps, the genetic model of metabolic syndrome, were fed a normal salt (0.5% NaCl) or high-salt (8% NaCl) diet for 4 weeks. In SHR/NDmcr-cps, salt loading induced severe hypertension, abnormal left ventricular relaxation, and perivascular fibrosis. Salt-loaded SHR/NDmcr-cps also exhibited overproduction of reactive oxygen species and upregulation of mineralocorticoid receptor-dependent gene expression, such as Na(+)/H(+) exchanger-1 and serum- and glucocorticoid-inducible kinase-1 in the cardiac tissue. However, in spontaneously hypertensive rats, salt loading did not cause these cardiac abnormalities despite a similar increase in blood pressure. An antioxidant, tempol, prevented salt-induced diastolic dysfunction, perivascular fibrosis, and upregulation of mineralocorticoid receptor signals in SHR/NDmcr-cps. Moreover, a selective mineralocorticoid receptor antagonist, eplerenone, prevented not only diastolic dysfunction but also overproduction of reactive oxygen species in salt-loaded SHR/NDmcr-cps. These results suggest that metabolic syndrome is a predisposed condition for salt-induced left ventricular diastolic dysfunction, possibly via increased oxidative stress and enhanced mineralocorticoid receptor signals.

Topics: Aldosterone; Animals; Blood Pressure Determination; Disease Models, Animal; Echocardiography, Doppler; Eplerenone; Heart Failure, Diastolic; Heart Function Tests; Male; Metabolic Syndrome; Random Allocation; Rats; Rats, Inbred SHR; Reactive Oxygen Species; Reference Values; Sensitivity and Specificity; Sodium Chloride; Spironolactone; Urinalysis; Ventricular Dysfunction, Left

Recent data indicate that aldosterone aggravates cyclosporin A (CsA)-induced nephrotoxicity. We examined whether the mineralocorticoid receptor (MR) blocker eplerenone (EPL) antagonized early deterioration of renal function and blood pressure (BP) increase in CsA-treated rats.. Male Sprague-Dawley rats received CsA (15 mg/kg/day i.p.) and/or EPL (100 mg/kg/day p.o.) for 21 days. After 2 weeks, arterial, venous and urinary bladder catheters were implanted and the rats were trained to accept a restraining device allowing arterial blood sampling and direct measurement of BP and renal function. BP was measured on-line in conscious rats.. CsA significantly increased systolic BP: 139 +/- 4 versus 134 +/- 2 mmHg, reduced body weight gain: -5 +/- 6 versus 36 +/- 7 g, glomerular filtration rate (GFR): 1.02 +/- 0.16 versus 2.64 +/- 0.27 ml/min, renal blood flow (RBF): 5.3 +/- 2.4 versus 13.5 +/- 2.1 ml/min and lithium clearance (C(Li+)): 0.16 +/- 0.04 versus 0.26 +/- 0.07 ml/min compared to controls. These changes were prevented by simultaneous EPL treatment: systolic BP, 130 +/- 4 mmHg; weight gain, 53 +/- 7 g; GFR, 1.67 +/- 0.26 ml/min; RBF, 12.3 +/- 2.1 ml/min and C(Li+), 0.27 +/- 0.03 ml/min. Analysis of kidney morphology after the CsA treatment showed hyaline vacuolization in tubules and vascular depositions in arterioles; these changes were less pronounced after combination therapy. No significant changes were seen regarding haemoglobin, haematocrit, plasma renin and vasopressin, plasma and urinary sodium, potassium, or osmolality.. MR blockade by EPL prevented short-term alterations in GFR, RBF and hypertension associated with CsA nephrotoxicity. We conclude that the aldosterone-MR pathway contributes markedly to the renal toxicity induced by this calcineurin inhibitor.

Topics: Animals; Blood Pressure; Cyclosporine; Disease Models, Animal; Eplerenone; Glomerular Filtration Rate; Kidney; Kidney Function Tests; Male; Mineralocorticoid Receptor Antagonists; Rats; Rats, Sprague-Dawley; Receptors, Mineralocorticoid; Regional Blood Flow; Spironolactone

Topics: Angioplasty, Balloon, Coronary; Animals; Collagen; Coronary Restenosis; Disease Models, Animal; Eplerenone; Humans; Hyperplasia; Mineralocorticoid Receptor Antagonists; Spironolactone; Stents; Swine; Tunica Intima

We investigated the role of nuclear factor kappaB (NF-kappaB) in the cytokine-mediated induction of cyclooxygenase-2 activity in the paraventricular nucleus of hypothalamus (PVN), a critical cardiovascular and autonomic center, in rats with heart failure (HF). Sprague-Dawley rats underwent coronary artery ligation to induce HF or sham surgery. HF rats were treated orally for 6 weeks with vehicle (tap water), the NF-kappaB inhibitor pyrrolidine dithiocarbamate (150 mg/kg per day), or the mineralocorticoid receptor antagonist eplerenone (30 mg/kg per day), which has been shown to reduce circulating proinflammatory cytokines in this model. Compared with sham surgery, HF rats had higher (P<0.05) levels of aldosterone, interleukin-1beta and norepinephrine in plasma and prostaglandin E2 in cerebrospinal fluid. In the PVN, NF-kappaB p50 precursor p105 mRNA increased, and mRNA for its inhibitor, IkappaB, decreased (P<0.05). Cyclooxygenase-2 mRNA and protein expression was increased in perivascular cells of the PVN. Both pyrrolidine dithiocarbamate and eplerenone reduced (P<0.05) p105 mRNA and increased IkappaB mRNA in PVN. Both also reduced (P<0.05) cyclooxygenase-2 mRNA and protein expression in PVN, cerebrospinal fluid prostaglandin E2, and plasma norepinephrine. Eplerenone, but not pyrrolidine dithiocarbamate, reduced plasma interleukin-1beta. Pyrrolidine dithiocarbamate and eplerenone had no effect on plasma aldosterone. The results suggest that activation of NF-kappaB is an intermediary step in cytokine-mediated induction of cyclooxygenase-2 in the PVN of HF rats. By enhancing access of prostaglandin E2 to hypothalamic neurons, this mechanism may contribute to augmented sympathetic nerve activity in HF.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Cyclooxygenase 2; Cytokines; Disease Models, Animal; Eplerenone; Heart Failure; Male; NF-kappa B; Paraventricular Hypothalamic Nucleus; Pyrrolidines; Rats; Rats, Sprague-Dawley; Spironolactone; Thiocarbamates

Eplerenone, a mineralocorticoid receptor antagonist, is reported to be effective to prevent end-stage cardiovascular damage induced by aldosterone. However, the effect of eplerenone on brain damage is not fully understood. Here, we investigated whether pretreatment with eplerenone attenuates stroke size in mice subjected to middle cerebral artery occlusion. Middle cerebral artery occlusion with a microfilament technique induced focal ischemia, to approximately 25% of the total area in a coronal section of the brain. Treatment with eplerenone at a dose of 1.67 mg/g chow significantly reduced the ischemic area, ischemic volume, and neurological deficit, without a blood pressure-lowering effect. Laser-Doppler flowmetry analysis showed a decrease in surface cerebral blood flow in the peripheral region after 1 h of middle cerebral artery occlusion. This decrease was smaller in mice treated with eplerenone. Superoxide production evaluated by staining with dihydroethidium was attenuated in the ischemic area of the brain in eplerenone-treated mice. Taken together, our findings suggest that eplerenone has a protective effect on ischemic brain damage, at least partly due to improvement of cerebral blood flow in the penumbra and reduction of oxidative stress.

Topics: Animals; Blood Pressure; Brain Ischemia; Disease Models, Animal; Eplerenone; Infarction, Middle Cerebral Artery; Male; Mice; Mice, Inbred C57BL; Mineralocorticoid Receptor Antagonists; Spironolactone; Stroke Volume; Superoxides

Tenascin-C is an extracellular matrix glycoprotein that is supposed to be a profibrotic molecule in various fibrogenic processes. To elucidate its significance for myocardial fibrosis in the hypertensive heart, we used a mouse model with infusion of angiotensin II and examined results by histology, immunohistochemistry, in situ hybridization, and quantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR). Angiotensin II treatment elevated blood pressure and expression of tenascin-C by interstitial fibroblasts in perivascular fibrotic lesions, and angiotensin II infusion caused accumulation of macrophages. It also upregulated expression of collagen Ialpha2; IIIalpha1; and proinflammatory/profibrotic mediators including transforming growth factor beta (TGFbeta), platelet-derived growth factor alpha (PDGF-A), PDGF-B, and PDGF-receptor alpha, but not IL-1beta and PDGF-receptor beta, in the myocardium. Treatment with an aldosterone receptor antagonist, eplerenone, significantly attenuated angiotensin II-induced fibrosis, expression of tenascin-C, and inflammatory changes without affecting the blood pressure level. In vitro, neither eplerenone nor aldosterone exerted any influence on tenascin-C expression of cardiac fibroblasts, whereas angiotensin II, TGF-beta1, and PDGF significantly upregulated expression of tenascin-C. These results suggest that, in the angiotensin II-induced hypertensive mouse heart: (1) tenascin-C may be involved in the progression of cardiac fibrosis and (2) aldosterone may elicit inflammatory reactions in myocardium, which might, in turn, induce tenascin-C synthesis of fibroblasts through at least 2 pathways mediated by TGF-beta and PDGF-A-B/PDGF-receptor alpha.

Topics: Aldosterone; Analysis of Variance; Angiotensin II; Animals; Blood Pressure; Body Weight; Cytokines; Disease Models, Animal; Eplerenone; Female; Fibroblasts; Fibrosis; Hypertension; Immunohistochemistry; In Situ Hybridization; Inflammation Mediators; Intercellular Signaling Peptides and Proteins; Macrophages; Mice; Mice, Inbred BALB C; Mineralocorticoid Receptor Antagonists; Myocardium; Reverse Transcriptase Polymerase Chain Reaction; Spironolactone; Tenascin; Up-Regulation; Vasoconstrictor Agents

Mineralocorticoid receptor blockade improves mortality early after myocardial infarction (MI). This study investigated the vascular effects of mineralocorticoid receptor blockade in the early phase postinfarction in rats. Starting immediately after coronary ligation, male Wistar rats were treated with placebo or eplerenone (100 mg/kg/d). After 7 days, hemodynamic assessment was performed and endothelial function was determined. Maximum acetylcholine-induced relaxation was significantly attenuated in aortic rings from rats with heart failure after MI, and ameliorated by eplerenone treatment. Endothelium-independent relaxation by DEA-NONOate was similar among the groups. Endothelial NO synthase phosphorylation was reduced in the aorta of MI rats and restored by eplerenone therapy. Angiotensin I-induced vasoconstriction as well as angiotensin-converting enzyme protein levels were enhanced in aortas from MI placebo rats, and reduced by mineralocorticoid receptor inhibition. Aortic reactive oxygen species formation as well as the expression of the NAD(P)H oxidase subunit p22(phox) were increased after MI and normalized in eplerenone treated rats. In conclusion, mineralocorticoid receptor antagonism improved endothelial dysfunction in the early phase post-MI. Underlying mechanisms involve inhibition of vascular angiotensin-converting enzyme upregulation and improvement of endothelial NO synthase-derived NO bioavailability.

Topics: Animals; Aorta, Thoracic; Disease Models, Animal; Dose-Response Relationship, Drug; Eplerenone; Male; Mineralocorticoid Receptor Antagonists; Myocardial Infarction; NADPH Oxidases; Organ Culture Techniques; Oxidative Stress; Rats; Rats, Wistar; Reactive Oxygen Species; Spironolactone; Time Factors; Vasodilation; Vasodilator Agents; Vasomotor System

Topics: Aldosterone; Animals; Blood Coagulation; Blood Pressure; Carboxypeptidase B2; Disease Models, Animal; Eplerenone; Infusions, Intravenous; Male; Mineralocorticoid Receptor Antagonists; Plasminogen Activator Inhibitor 1; Rats; Rats, Wistar; Receptors, Mineralocorticoid; Spironolactone; Thromboplastin; Thrombosis; Tissue Plasminogen Activator

Aldosterone is implicated in the pathogenesis of proteinuria and chronic kidney disease. We previously demonstrated the contribution of elevated serum aldosterone in the early nephropathy of SHR/NDmcr-cp (SHR/cp), a rat model of metabolic syndrome. In the present study, we investigated the effect of salt loading on renal damage in SHR/cps and explored the underlying mechanisms. SHR/cps fed a high-sodium diet for 4 weeks developed severe hypertension, massive proteinuria, and advanced renal lesions. High salt also worsened glomerular podocyte impairment. Surprisingly, selective mineralocorticoid receptor (MR) antagonist eplerenone dramatically ameliorated the salt-induced proteinuria and renal injury in SHR/cps. Although salt loading reduced circulating aldosterone, it increased nuclear MR and expression of aldosterone effector kinase Sgk1 in the kidney. Gene expressions of transforming growth factor-beta1 and plasminogen activator inhibitor-1 were also enhanced in the kidneys of salt-loaded SHR/cps, and eplerenone completely inhibited these injury markers. To clarify the discrepancy between decreased aldosterone and enhanced MR signaling by salt, we further investigated the role of oxidative stress, a putative key factor mediating salt-induced tissue damage. Interestingly, antioxidant Tempol attenuated the salt-evoked MR upregulation and Sgk1 induction and alleviated proteinuria and renal histological abnormalities, suggesting the involvement of oxidative stress in salt-induced MR activation. MR activation by salt was not attributed to increased serum corticosterone or reduced 11beta-hydroxysteroid dehydrogenase type 2 activity. In conclusion, sodium loading exacerbated proteinuria and renal injury in metabolic syndrome rats. Salt reduced circulating aldosterone but caused renal MR activation at least partially via induction of oxidative stress, and eplerenone effectively improved the nephropathy.

Topics: Aldosterone; Animals; Antioxidants; Cyclic N-Oxides; Disease Models, Animal; Eplerenone; Hypertension; Kidney Diseases; Male; Metabolic Syndrome; Obesity; Oxidative Stress; Rats; Rats, Inbred SHR; Rats, Mutant Strains; Receptors, Cell Surface; Receptors, Leptin; Receptors, Mineralocorticoid; Renin; Sodium Chloride, Dietary; Spin Labels; Spironolactone

Enhanced extracellular matrix accumulation rather than cell proliferation contributes to later stages of in-stent restenosis. Aldosterone itself has been shown to increase cardiovascular fibrosis, therefore, we studied the suppressive effects of eplerenone, a new aldosterone receptor antagonist, on neointimal hyperplasia after coronary stent implantation in swine.. Palmatz-Shatz stents were implanted in the left anterior descending artery of 36 pigs. One hundred milligrams of Eplerenone was orally administered from 1 week before, to 4 weeks after stent implantation in Group E (n=18), and vehicle was given to Group C (n=18). Pigs were sacrificed 1 or 4 weeks after stent implantation. The number of infiltrating macrophages was calculated at 1 week. Morphometrical analysis was performed to measure the area of each layer, and %area of fibrosis and mRNA for collagen I, III and TGF-beta was analyzed by RT-PCR at 4 weeks.. The number of infiltrating macrophages was less in Group E than in Group C (p<0.01). The overall size of coronary arteries at 4 weeks was similar in both groups. However, the luminal area was larger in Group E than in Group C (p<0.05), and the intimal area was smaller in Group E than in Group C (p<0.05). The %area of fibrosis was significantly less in Group E than in Group C at 4 weeks (p<0.01). In Group E, the expression of mRNA for collagen I, III and TGF-beta was significantly reduced.. Orally administered eplerenone attenuated collagen accumulation within the neointima, thereby inhibiting neointimal hyperplasia after stent implantation.

Topics: Actins; Administration, Oral; Animals; Blood Vessel Prosthesis Implantation; Collagen Type I; Collagen Type III; Coronary Restenosis; Coronary Vessels; Disease Models, Animal; Eplerenone; Fibrosis; Hyperplasia; Immunohistochemistry; Macrophages; Male; Mineralocorticoid Receptor Antagonists; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Spironolactone; Stents; Swine; Time Factors; Transforming Growth Factor beta; Tunica Intima

The renin-angiotensin-aldosterone system (RAAS) has been implicated in the pathophysiology of salt-induced hypertension. Angiotensin converting enzyme inhibitors, angiotensin II-type 1 receptor blockers, and aldosterone receptor blockers are used to treat hypertension and congestive heart disease. In addition to their blood pressure lowering effects, they appear to protect against myocardial, renal, and vascular damage. In various models of hypertension, generation of reactive oxygen species is increased in the vasculature and that treatment with antioxidants or superoxide dismutase mimetics (e.g., tempol) improves vascular function and structure and reduces blood pressure. The purpose of this study was to examine the effects of enalapril, an angiotensin II converting enzyme inhibitor; eplerenone, a selective aldosterone receptor antagonist; and tempol, a superoxide dismutase mimetic, on salt-induced hypertension in Dahl Salt-Sensitive rats. The rats were placed on a high salt (HS; 8%) diet for 3 weeks prior to switching to a normal salt (0.3%) diet for an additional 3 weeks. While on the normal salt (NS) diet, rats were treated with enalapril (30 mg/kg/day in the drinking water), eplerenone (100 mg/kg/day by gavage), tempol (1 mM/day in the drinking water), eplerenone + enalapril, eplerenone + enalapril + tempol, or without drug treatment (control). After 3 weeks on HS diet, systolic blood pressure rose from 127 +/- 7 to 206 +/- 11 mm Hg and remained elevated when switched to NS diet. Subsequently, treatment with eplerenone alone or in combination with enalapril and tempol produced a stepwise reduction in systolic blood pressure reaching -80 mm Hg; however, enalapril and tempol alone produced more modest pressure reduction (approximately -35 mmHg). Plasma levels of prostacyclin and nitric oxide were elevated in rats treated with enalapril and eplerenone alone or in combination. Enalapril and eplerenone alone and in combination reduced heart and kidney levels of angiotensin II and aldosterone when compared with control. Renal and heart levels of reduced glutathione were diminished by eplerenone alone; however, enalapril tended to attenuate the effect of eplerenone on reduced glutathione levels in the heart. The findings from this study suggest that eplerenone reduces salt-induced hypertension by increasing endothelium-derived relaxing factors, inhibiting RAAS components and oxidative stress. (353words).

Topics: Aldosterone; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Antioxidants; Blood Pressure; Cyclic N-Oxides; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Enalapril; Eplerenone; Epoprostenol; Hypertension; Male; Nitric Oxide; Oxidative Stress; Rats; Rats, Inbred Dahl; Sodium Chloride; Spin Labels; Spironolactone; Treatment Outcome

Metabolic syndrome is an important risk factor for proteinuria and chronic kidney disease independent of diabetes and hypertension; however, the underlying mechanisms have not been elucidated. Aldosterone is implicated in target organ injury of obesity-related disorders. This study investigated the role of aldosterone in the early nephropathy of 17-wk-old SHR/NDmcr-cp, a rat model of metabolic syndrome. Proteinuria was prominent in SHR/NDmcr-cp compared with nonobese SHR, which was accompanied by podocyte injury as evidenced by foot process effacement, induction of desmin and attenuation of nephrin. Serum aldosterone level, renal and glomerular expressions of aldosterone effector kinase Sgk1, and oxidative stress markers all were elevated in SHR/NDmcr-cp. Mineralocorticoid receptors were expressed in glomerular podocytes. Eplerenone, a selective aldosterone blocker, effectively improved podocyte damage, proteinuria, Sgk1, and oxidant stress. An antioxidant tempol also alleviated podocyte impairment and proteinuria, along with inhibition of Sgk1. As for the mechanisms of aldosterone excess, visceral adipocytes that were isolated from SHR/NDmcr-cp secreted substances that stimulate aldosterone production in adrenocortical cells. The aldosterone-releasing activity of adipocytes was not inhibited by candesartan. Adipocytes from nonobese SHR did not show such activity. In conclusion, SHR/NDmcr-cp exhibit enhanced aldosterone signaling, podocyte injury, and proteinuria, which are ameliorated by eplerenone or tempol. The data also suggest that adipocyte-derived factors other than angiotensin II might contribute to the aldosterone excess of this model.

Topics: Adipocytes; Adrenal Glands; Aldosterone; Animals; Cyclic N-Oxides; Disease Models, Animal; Eplerenone; Immediate-Early Proteins; Kidney Failure, Chronic; Male; Metabolic Syndrome; Mineralocorticoid Receptor Antagonists; Obesity; Podocytes; Protein Serine-Threonine Kinases; Protein Synthesis Inhibitors; Proteinuria; Rats; Rats, Inbred SHR; Receptors, Mineralocorticoid; RNA, Messenger; Spin Labels; Spironolactone

Spironolactone, a nonselective aldosterone blocker, has a cardioprotective effect; however, significant endocrine side effects limit its use. Eplerenone is a new selective aldosterone blocker. We investigated whether eplerenone attenuates cardiac remodeling and improves function in a mouse model of heart failure and whether coadministration of eplerenone and an angiotensin-converting enzyme inhibitor (ACEi) provides better cardioprotection than either agent alone.. C57BL/6J mice were subjected to myocardial infarction (MI) by ligating the left anterior descending coronary artery. Two weeks later, the mice were either left untreated or treated with (1) eplerenone, (2) ACEi, or (3) eplerenone plus ACEi for 12 weeks. Systolic blood pressure (SBP) was measured and echocardiography performed before MI and weekly thereafter. At the end of the study, interstitial collagen fraction (ICF) and myocyte cross-sectional area (MCSA) were examined histologically. We found that (1) eplerenone significantly improved ejection fraction and cardiac output and decreased left ventricular (LV) systolic area, LV weight, ICF, and MCSA independently of changes in SBP compared with untreated animals; (2) ACEi had similar beneficial effects, accompanied by a significant reduction in SBP; and (3) combined treatment offered limited additional benefit beyond monotherapy.. In mice with MI, eplerenone attenuates progression of heart failure comparably to ACEi, and its effect is independent of BP lowering.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Cardiac Output; Collagen; Disease Models, Animal; Drug Therapy, Combination; Echocardiography; Eplerenone; Heart Failure; Mice; Mice, Inbred C57BL; Mineralocorticoid Receptor Antagonists; Muscle Cells; Myocardial Infarction; Spironolactone; Stroke Volume; Treatment Outcome; Ventricular Remodeling

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. This enzyme converts glucocorticoids to receptor-inactive metabolites, allowing aldosterone occupancy of cardiomyocyte mineralocorticoid receptors. Transgenic mice were normotensive but spontaneously developed cardiac hypertrophy, fibrosis, and heart failure and died prematurely on a normal salt diet. Eplerenone, a selective aldosterone blocker, ameliorated this phenotype. These studies confirm the deleterious consequences of inappropriate activation of cardiomyocyte mineralocorticoid receptors by aldosterone and reveal a tonic inhibitory role of glucocorticoids in preventing such outcomes under physiological conditions. In addition, these data support the hypothesis that aldosterone blockade may provide additional therapeutic benefit in the treatment of heart failure.

Topics: 11-beta-Hydroxysteroid Dehydrogenase Type 2; Aldosterone; Animals; Blood Pressure; Cardiomegaly; Disease Models, Animal; Echocardiography; Eplerenone; Female; Fibrosis; Gene Expression Regulation; Gene Expression Regulation, Enzymologic; Heart Failure; Hydroxysteroid Dehydrogenases; Kidney; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mineralocorticoid Receptor Antagonists; Myocardium; Myocytes, Cardiac; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Spironolactone; Up-Regulation; Ventricular Dysfunction, Left

Previous studies have demonstrated the development of cardiac fibrosis in aldosterone (Aldo)-salt hypertensive rats. Our aim was to determine the effects of Aldo and the Aldo receptor antagonist eplerenone (Epl) on in vivo mechanical properties of the carotid artery using echo-tracking system.. Aldo was administered (1 microg/h) in uninephrectomized Sprague-Dawley rats (SD) receiving a high-salt diet from 8 to 12 weeks of age. Uninephrectomized control SD rats received a normal salt diet without Aldo. Three groups of Aldo-salt rats were treated with 1, 10, or 30 mg/kg(-1) x d(-1) of Epl by gavage. Elasticity was measured by elastic modulus (Einc)-wall stress curves using medial cross-sectional area (MCSA). The structure of the arterial wall was analyzed by histomorphometry (elastin and collagen), immunohistochemistry (EIIIA fibronectin, Fn), and Northern blot (collagens I and III). Aldo produced increased systolic arterial pressure, pulse pressure, Einc, MCSA, and EIIIA Fn with no change in wall stress or elastin and collagen densities compared with controls without Aldo. No differences in collagen mRNA levels were detected between groups. Epl blunted the increase in pulse pressure in Aldo rats and normalized Einc-wall stress curves, MCSA, and EIIIA Fn. These effects were dose dependent and not accompanied by a reduction in wall stress.. Aldo is able to increase arterial stiffness associated with Fn accumulation, independently of wall stress. The preventive effects of Epl suggest a direct role for mineralocorticoid receptors in mechanical and structural alterations of large vessels in rat hyperaldosteronism.

Topics: Aldosterone; Animals; Blood Pressure; Blotting, Northern; Carotid Arteries; Collagen; Collagen Type I; Collagen Type III; Disease Models, Animal; Dose-Response Relationship, Drug; Elasticity; Elastin; Eplerenone; Fibronectins; Hyperaldosteronism; Immunohistochemistry; Injections, Subcutaneous; Male; Mineralocorticoid Receptor Antagonists; Nephrectomy; Rats; Rats, Sprague-Dawley; RNA, Messenger; Sodium, Dietary; Spironolactone; Ultrasonography; Vascular Patency

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.. HF was produced in 14 dogs by intracoronary microembolizations that were discontinued when LV ejection fraction (EF) was between 30% and 40%. Two weeks after the last embolization, dogs were randomized to 3 months of oral therapy with eplerenone (10 mg/kg twice daily, n=7) or no therapy at all (control, n=7). Hemodynamic measurements were made just before randomization and were repeated at the end of 3 months of therapy. In control dogs, LV end-diastolic and end-systolic volume increased significantly (62+/-4 versus 68+/-4 mL, P<0.001, and 38+/-3 versus 47+/-3 mL, P<0.001, respectively), and EF decreased significantly (38+/-1% versus 31+/-2%, P<0.001). In contrast, end-diastolic volume, end-systolic volume, and EF remained unchanged during the 3 months of treatment in eplerenone-treated dogs. LV end-diastolic wall stress increased significantly in control dogs but decreased significantly in eplerenone-treated dogs. Compared with control, eplerenone was associated with a 28% reduction in cardiomyocyte cross-sectional area, a 37% reduction of volume fraction of reactive interstitial fibrosis, and a 34% reduction of volume fraction of replacement fibrosis.. Our results indicate that long-term therapy with eplerenone prevents progressive LV dysfunction and attenuates LV remodeling in dogs with chronic HF.

Topics: Administration, Oral; Animals; Chronic Disease; Disease Models, Animal; Disease Progression; Dogs; Echocardiography; Enzyme Activation; Eplerenone; Fibroblast Growth Factor 2; Heart; Heart Failure; Hemodynamics; Mineralocorticoid Receptor Antagonists; Myocardium; RNA, Messenger; Spironolactone; Stroke Volume; Treatment Outcome; Ventricular Dysfunction, Left; Ventricular Remodeling

To determine the extent to which dietary sodium modulates aldosterone-induced cardiovascular damage, and to determine whether increased dietary potassium can prevent this damage, we used the Nomega-nitro-L-arginine methyl ester (L-NAME)/angiotensin II (Ang II) rat model of cardiac injury. This model is dependent on the presence of aldosterone for the occurrence of myocardial damage. Two sets of experiments were performed. In the first set, the following groups were studied: (1) 1% NaCl to drink (control group); (2) L-NAME/Ang II with water to drink (low salt group); (3) L-NAME/Ang II/1% NaCl (high salt group); (4) L-NAME/Ang II/1% NaCl/eplerenone (eplerenone group). Systolic blood pressure increased similarly in all groups compared with controls. Compared with the controls, the high salt group, but not the low salt or eplerenone groups, developed significant myocardial damage. In the second set of experiments three groups of animals were studied: (1) L-NAME/Ang II/1%NaCl (high salt group) (2) L-NAME/Ang II/1%NaCl/eplerenone (eplerenone group), and (3) L-NAME/Ang II/1%NaCl with an extra 1% KCl in food (high dietary potassium group). Eplerenone, but not dietary potassium supplementation, prevented the development of cardiac damage. Thus, mineralocorticoid receptor antagonist treatment and low sodium diet were effective in preventing cardiac damage, which suggests that a minimal level of aldosterone and a moderately high sodium diet are both required for the development of the cardiovascular damage in the L-NAME/Ang II model. The inability of potassium supplementation to reduce myocardial damage suggests that eplerenone's protective effect is not due to its potassium-sparing ability, but is rather related to some other feature of its selective aldosterone antagonism.

Topics: Aldosterone; Angiotensin II; Animals; Diet, Sodium-Restricted; Disease Models, Animal; Eplerenone; Heart Diseases; Male; Mineralocorticoid Receptor Antagonists; NG-Nitroarginine Methyl Ester; Potassium; Rats; Rats, Wistar; Spironolactone