Mineralocorticoid receptor (MR) antagonist eplerenone and MR modulator balcinrenone prevent renal extracellular matrix remodeling and inflammation via the MR/proteoglycan/TLR4 pathway.

Excessive activation of the mineralocorticoid receptor (MR) is implicated in cardiovascular and renal disease. Decreasing MR activation with MR antagonists (MRA) is effective to slow chronic kidney disease (CKD) progression and its cardiovascular comorbidities in animal models and patients. The present study evaluates the effects of the MR modulator balcinrenone and the MRA eplerenone on kidney damage in a metabolic CKD mouse model combining nephron reduction and a 60% high-fat diet. Balcinrenone and eplerenone prevented the progression of renal damages, extracellular matrix remodeling and inflammation to a similar extent. We identified a novel mechanism linking MR activation to the renal proteoglycan deposition and inflammation via the TLR4 pathway activation. Balcinrenone and eplerenone similarly blunted this pathway activation.

When to use spironolactone, eplerenone or finerenone in the spectrum of cardiorenal diseases.

Kidney disease frequently coexists with cardiovascular (CV) diseases, and this dual presence significantly amplifies the risk of adverse clinical outcomes. Shared pathophysiological mechanisms and common CV risk factors contribute to the increased expression of mineralocorticoid receptors, which in turn can drive the progression of chronic CV-kidney disorders. The steroidal mineralocorticoid receptor antagonists (MRAs) spironolactone and eplerenone have demonstrated efficacy in improving patient outcomes in cases of heart failure with reduced ejection fraction or after a myocardial infarction, but have limited value in patients with chronic kidney disease. The non-steroidal MRA finerenone has now established itself as a foundational guideline-recommended therapy in patients with diabetic kidney disease. To date, these pharmacological agents have been developed in distinct patient populations. The consequences of their distinct pharmacological profiles necessitate further consideration. They have not undergone testing across the entire spectrum of cardiorenal scenarios, and the evidence base is currently being complemented with ongoing trials. In this review, we aim to synthesize the existing body of evidence and chart the future trajectory for the use of spironolactone, eplerenone and finerenone in improving clinical outcomes across the diverse spectrum of cardiorenal diseases. By consolidating the current state of knowledge, we seek to provide valuable insights for informed decision making in the management of patients with these complex and interconnected conditions.

Comparative effectiveness and safety of eplerenone and spironolactone in patients with heart failure: a systematic review and meta-analysis.

BACKGROUND: Eplerenone and spironolactone, recognized as mineralocorticoid receptor antagonists (MRAs), have been reported to improve clinical prognosis among individuals diagnosed with heart failure (HF). However, the difference in the clinical effects between eplerenone and spironolactone in individuals with HF remains uncertain. We aimed to assess the impact of eplerenone compared to spironolactone on clinical outcomes within the HF population. METHODS: An extensive search was executed in several databases (PubMed, Web of Science, Scopus, Cochrane Library). All relevant studies evaluating eplerenone compared to spironolactone in patients with HF were included. Dichotomous data were pooled as Hazard ratio (HR) or Risk ratio (RR) with a 95% confidence interval (CI). Our main outcome was all-cause mortality. Secondary outcomes included death from cardiovascular causes, treatment withdrawal, and gynecomastia. RESULTS: Ten studies, comprising 21,930 HF individuals, were included in our investigation. Eplerenone showed a lower risk of all-cause mortality (HR = 0.78, 95%CI [0.64 to 0.94], P = 0.009) and cardiovascular mortality (HR = 0.54, 95%CI [0.39, 0.74], P = 0.0001) compared to spironolactone. Furthermore, eplerenone exhibited a reduced risk of treatment withdrawal (RR = 0.69, 95% CI [0.62, 0.78], P = 0.0001) and gynecomastia (RR = 0.07, 95% CI [0.02 to 0.31], P = 0.0001) than spironolactone. CONCLUSION: Eplerenone revealed lower all-cause and cardiovascular mortality events in comparison to spironolactone. Moreover, eplerenone was associated with lower gynecomastia and treatment withdrawal events compared to spironolactone. Further well-designed randomized controlled trials are still warranted better to identify the clinical differences between eplerenone and spironolactone. TRIAL REGISTRATION: Protocol registration: https://doi.org/10.17605/OSF.IO/VNMGK.

Clinical Properties and Non-Clinical Testing of Mineralocorticoid Receptor Antagonists in In Vitro Cell Models.

Mineralocorticoid receptor antagonists (MRAs) are one of the renin-angiotensin-aldosterone system inhibitors widely used in clinical practice. While spironolactone and eplerenone have a long-standing profile in clinical medicine, finerenone is a novel agent within the MRA class. It has a higher specificity for mineralocorticoid receptors, eliciting less pronounced adverse effects. Although approved for clinical use in patients with chronic kidney disease and heart failure, intensive non-clinical research aims to further elucidate its mechanism of action, including dose-related selectivity. Within the field, animal models remain the gold standard for non-clinical testing of drug pharmacological and toxicological properties. Their role, however, has been challenged by recent advances in in vitro models, mainly through sophisticated analytical tools and developments in data analysis. Currently, in vitro models are gaining momentum as possible platforms for advanced pharmacological and pathophysiological studies. This article focuses on past, current, and possibly future in vitro cell models research with clinically relevant MRAs.

Comparative Analysis of The Effectiveness of Antihypertensive Therapy Including Spironolactone and Eplerenone in Patients With Essential Hypertension and Atrial Fibrillation.

AIM: To perform a comparative analysis of the efficacy of antihypertensive therapy (AHT) containing spironolactone or eplerenone in patients with essential arterial hypertension (AH) and atrial fibrillation (AF). MATERIAL AND METHODS: The study included 99 male and female patients with essential AH complicated by permanent AF, who were receiving the outpatient treatment at the National Specialized Scientific and Practical Medical Center of Cardiology (Tashkent). The patients aged 61.3±9.5 years, the mean duration of AH was 12.9±8.3 years. All patients were divided into two groups: Group 1, patients who completed a 6-month combination AHT containing spironolactone (n=51); Group 2, patients who completed a 6-month combination AHT containing eplerenone (n=48). AF was diagnosed by electrocardiogram (ECG) and/or 24-hour ECG monitoring according to standard diagnostic criteria. The ECG study was performed in compliance with the American Society of Echocardiography Guidelines in M- and B-modes. The degree of structural vascular alterations was determined by the intima-media thickness of the common carotid artery by duplex scanning and microalbuminuria in morning urine. The concentrations of sex hormones were measured by the enzyme immunoassay. The serum concentrations of lipids, glucose, creatinine, and uric acid were measured by the enzymatic method. The glomerular filtration rate (GFR) was calculated with the EPI formula. Results of all studies were considered statistically significant at p<0.05. RESULTS: The proportion of patients who achieved the target diastolic blood pressure (BP) values was significantly greater in the eplerenone-containing treatment group than in the spironolactone-containing treatment group: 87.8% vs. 67.5% (p=0.043). The proportion of patients who simultaneously achieved the target systolic and diastolic BP values was slightly greater in the eplerenone-containing treatment group than in the spironolactone-containing group (100% vs. 92.1%, p=0.060). The best cardioprotective efficacy was observed in the group of combination AHT containing eplerenone. Specifically, in Group 2, the left ventricular ejection fraction (LVEF) was significantly improved compared to Group 1: from 55.4±10.6% at baseline to 52.6±9.1% in Group 1 (p>0.05) and from 54.8±8.8% at baseline to 58.2±6.4% in Group 2 (p<0.02). Only in Group 2, the left atrial volume index (LAVI) was significantly decreased compared to Group 1. Thus, in Group 1, the LAVI changed from 42.2±15.1 ml/m2 at baseline to 40.4±12.2 ml/m2 (p>0.05) and in Group 2, from 41.2±15.3 ml/m2 at baseline to 37.3±13.5 ml/m2 after the treatment (p<0.05); the ∆% LAVI in the eplerenone group was -5.9% vs. -0.36% in the spironolactone group. In men of Group 1, estradiol significantly increased from 13.9±12.6 pmol/l at baseline to 22.7±12.4 pmol/l (p<0.001). CONCLUSION: The good antihypertensive efficacy of the 6-month combination therapy containing eplerenone was significantly superior to spironolactone in achieving the target BP values. The eplerenone-containing treatment significantly improved LVEF and decreased LAVI compared to the spironolactone-containing treatment. A trend towards a beneficial effect of the AHT containing eplerenone on concentrations of sex hormones was noted in both women and men.

Ocular Biodistribution of Spironolactone after a Single Intravitreal Injection of a Biodegradable Sustained-Release Polymer in Rats.

Sustained-release formulations for ocular delivery are of increasing interest given their potential to significantly improve treatment efficacy and patient adherence. The objectives of this study were (i) to develop a sustained-release formulation of spironolactone (SPL) using a biodegradable and injectable polymer, hexyl-substituted poly-lactic acid (hexPLA) and (ii) to investigate the ocular biodistribution and tolerability of SPL and its metabolites in rats in vivo over 1 month following a single intravitreal injection (IVT inj). The concentrations of SPL and its two principal active metabolites, 7α-thiomethylspironolactone and canrenone (CAN), in the different ocular compartments were determined at different time points (3, 7, and 31 days after IVT inj) using a validated ultra-high-performance liquid chromatography-mass spectrometry method. Systemic exposure following a single IVT inj of 5% SPL-hexPLA formulation was evaluated by quantifying SPL and its metabolites in the plasma. Ocular tolerability of the formulation was evaluated using in vivo retinal imaging and histology. In vitro release studies revealed a sustained release of SPL from 5% SPL-hexPLA for up to 65 days. In vivo studies showed that SPL and its metabolites were detected in all ocular tissues at 3 and 7 days post-IVT inj. At 31 days post-IVT inj, SPL and CAN were mainly detected in the retina. These results also highlighted the clearance pathway of SPL and its metabolite involving the anterior and posterior routes in the first week (days 3 and 7), then mainly the posterior segment in the last week (day 31). This study showed that a single IVT inj of 5% SPL-hexPLA in rats enabled sustained delivery of therapeutic amounts of SPL for up to 1 month to the retina without systemic exposure. This formulation may be of interest for the local treatment of diseases involving overactivation of the mineralocorticoid receptor in the chorioretina such as chronic central serous chorioretinopathy.

Aldosterone antagonists in addition to renin angiotensin system antagonists for preventing the progression of chronic kidney disease.

BACKGROUND: Treatment with angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) is used to reduce proteinuria and retard the progression of chronic kidney disease (CKD). However, resolution of proteinuria may be incomplete with these therapies and the addition of an aldosterone antagonist may be added to further prevent progression of CKD. This is an update of a Cochrane review first published in 2009 and updated in 2014. OBJECTIVES: To evaluate the effects of aldosterone antagonists (selective (eplerenone), non-selective (spironolactone or canrenone), or non-steroidal mineralocorticoid antagonists (finerenone)) in adults who have CKD with proteinuria (nephrotic and non-nephrotic range) on: patient-centred endpoints including kidney failure (previously know as end-stage kidney disease (ESKD)), major cardiovascular events, and death (any cause); kidney function (proteinuria, estimated glomerular filtration rate (eGFR), and doubling of serum creatinine); blood pressure; and adverse events (including hyperkalaemia, acute kidney injury, and gynaecomastia). SEARCH METHODS: We searched the Cochrane Kidney and Transplant Register of Studies up to 13 January 2020 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal, and ClinicalTrials.gov. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs that compared aldosterone antagonists in combination with ACEi or ARB (or both) to other anti-hypertensive strategies or placebo in participants with proteinuric CKD. DATA COLLECTION AND ANALYSIS: Two authors independently assessed study quality and extracted data. Data were summarised using random effects meta-analysis. We expressed summary treatment estimates as a risk ratio (RR) for dichotomous outcomes and mean difference (MD) for continuous outcomes, or standardised mean difference (SMD) when different scales were used together with their 95% confidence interval (CI). Risk of bias were assessed using the Cochrane tool. Evidence certainty was evaluated using GRADE. MAIN RESULTS: Forty-four studies (5745 participants) were included. Risk of bias in the evaluated methodological domains were unclear or high risk in most studies. Adequate random sequence generation was present in 12 studies, allocation concealment in five studies, blinding of participant and investigators in 18 studies, blinding of outcome assessment in 15 studies, and complete outcome reporting in 24 studies. All studies comparing aldosterone antagonists to placebo or standard care were used in addition to an ACEi or ARB (or both). None of the studies were powered to detect differences in patient-level outcomes including kidney failure, major cardiovascular events or death. Aldosterone antagonists had uncertain effects on kidney failure (2 studies, 84 participants: RR 3.00, 95% CI 0.33 to 27.65, I² = 0%; very low certainty evidence), death (3 studies, 421 participants: RR 0.58, 95% CI 0.10 to 3.50, I² = 0%; low certainty evidence), and cardiovascular events (3 studies, 1067 participants: RR 0.95, 95% CI 0.26 to 3.56; I² = 42%; low certainty evidence) compared to placebo or standard care. Aldosterone antagonists may reduce protein excretion (14 studies, 1193 participants: SMD -0.51, 95% CI -0.82 to -0.20, I² = 82%; very low certainty evidence), eGFR (13 studies, 1165 participants, MD -3.00 mL/min/1.73 m², 95% CI -5.51 to -0.49, I² = 0%, low certainty evidence) and systolic blood pressure (14 studies, 911 participants: MD -4.98 mmHg, 95% CI -8.22 to -1.75, I² = 87%; very low certainty evidence) compared to placebo or standard care. Aldosterone antagonists probably increase the risk of hyperkalaemia (17 studies, 3001 participants: RR 2.17, 95% CI 1.47 to 3.22, I² = 0%; moderate certainty evidence), acute kidney injury (5 studies, 1446 participants: RR 2.04, 95% CI 1.05 to 3.97, I² = 0%; moderate certainty evidence), and gynaecomastia (4 studies, 281 participants: RR 5.14, 95% CI 1.14 to 23.23, I² = 0%; moderate certainty evidence) compared to placebo or standard care. Non-selective aldosterone antagonists plus ACEi or ARB had uncertain effects on protein excretion (2 studies, 139 participants: SMD -1.59, 95% CI -3.80 to 0.62, I² = 93%; very low certainty evidence) but may increase serum potassium (2 studies, 121 participants: MD 0.31 mEq/L, 95% CI 0.17 to 0.45, I² = 0%; low certainty evidence) compared to diuretics plus ACEi or ARB. Selective aldosterone antagonists may increase the risk of hyperkalaemia (2 studies, 500 participants: RR 1.62, 95% CI 0.66 to 3.95, I² = 0%; low certainty evidence) compared ACEi or ARB (or both). There were insufficient studies to perform meta-analyses for the comparison between non-selective aldosterone antagonists and calcium channel blockers, selective aldosterone antagonists plus ACEi or ARB (or both) and nitrate plus ACEi or ARB (or both), and non-steroidal mineralocorticoid antagonists and selective aldosterone antagonists. AUTHORS' CONCLUSIONS: The effects of aldosterone antagonists when added to ACEi or ARB (or both) on the risks of death, major cardiovascular events, and kidney failure in people with proteinuric CKD are uncertain. Aldosterone antagonists may reduce proteinuria, eGFR, and systolic blood pressure in adults who have mild to moderate CKD but may increase the risk of hyperkalaemia, acute kidney injury and gynaecomastia when added to ACEi and/or ARB.

Spironolactone blocks Epstein-Barr virus production by inhibiting EBV SM protein function.

Clinically available drugs active against Epstein-Barr virus (EBV) and other human herpesviruses are limited to those targeting viral DNA replication. To identify compounds directed against other steps in the viral life cycle, we searched for drugs active against the EBV SM protein, which is essential for infectious virus production. SM has a highly gene-specific mode of action and preferentially enhances expression of several late lytic cycle EBV genes. Here we demonstrate that spironolactone, a mineralocorticoid receptor antagonist approved for clinical use, inhibits SM function and infectious EBV production. Expression of EBV viral capsid antigen is highly SM dependent, and spironolactone inhibits viral capsid antigen synthesis and capsid formation, blocking EBV virion production at a step subsequent to viral DNA replication. In addition, spironolactone inhibits expression of other SM-dependent genes necessary for infectious virion formation. We further demonstrate that molecules structurally related to spironolactone with similar antimineralocorticoid blocking activity do not inhibit EBV production. These findings pave the way for development of antiherpesvirus drugs with new mechanisms of action directed against SM and homologous essential proteins in other herpesviruses.

Eplerenone pretreatment protects the myocardium against ischaemia/reperfusion injury through the phosphatidylinositol 3-kinase/Akt-dependent pathway in diabetic rats.

We investigated the eplerenone-induced, PI3K/Akt- and GSK-3ß-mediated cardioprotection against ischemia/reperfusion (I/R) injury in diabetic rats. The study groups comprising diabetic rats were treated for 14 days with 150 mg/kg/day eplerenone orally and 1 mg/kg wortmannin (PI3K/Akt antagonist) intraperitoneally with eplerenone. On the 15th day, the rats were exposed to I/R injury by 20-min occlusion of the left anterior descending coronary artery followed by 30 min of reperfusion. The hearts were processed for biochemical, molecular, and histological investigations. The I/R injury in diabetic rats inflicted a significant rise in the oxidative stress and apoptosis along with a decrease in the arterial and ventricular function and the expressions of PI3K/Akt and GSK-3ß proteins. Eplerenone pretreatment reduced the arterial pressure, cardiac inotropy, and lusitropy. It significantly reduced apoptosis and cardiac injury markers. The histology revealed cardioprotection in eplerenone-treated rats. Eplerenone up-regulated the PI3K/Akt and reduced the GSK-3ß expression. The group receiving wortmannin with eplerenone was deprived eplerenone-induced cardioprotection. Our results reveal the eplerenone-induced cardioprotection against I/R injury in diabetic rats and substantiate the involvement of PI3K/Akt and GSK-3ß pathways in its efficacy.

Mineralocorticoid Receptor Blockers and Aldosterone to Renin Ratio: A Randomized Controlled Trial and Observational Data.

Current guidelines recommend to withdraw mineralocorticoid receptor (MR) blocker treatment for at least 4 weeks when measuring the aldosterone to renin ratio (ARR) as a screening test for primary aldosteronism (PA). We aimed to evaluate the effect of MR blocker treatment on ARR and its components, plasma aldosterone concentration (PAC), and direct renin concentration (DRC). First, we performed a post-hoc analysis of the effect of eplerenone on parathyroid hormone levels in primary hyperparathyroidism (EPATH) study, a randomized controlled trial (RCT) in 110 patients with primary hyperparathyroidism (pHPT). Patients were 1:1 randomly assigned to receive either 25 mg eplerenone once daily (up-titration after 4 weeks to 50 mg/day) or placebo for 8 weeks. Second, we measured the ARR in 4 PA patients from the Graz Endocrine Causes of Hypertension Study (GECOH) before and after MR blocker treatment. Ninety-seven participants completed the EPATH trial, and the mean treatment effect (95% confidence interval) for log(e)ARR was 0.08 (-0.32 to 0.48) ng/dl/µU/ml (p=0.694). The treatment effect was 0.71 (0.47 to 0.96; p<0.001) ng/dl for log(e)PAC and 0.64 (0.19 to 1.10; p=0.006) µU/ml for log(e)DRC, respectively. In the 4 PA patients, the ARR decreased from 11.24±3.58 at baseline to 2.70±1.03 (p=0.013) ng/dl/µU/ml after MR blocker treatment. In this study with limited sample size, MR blocker treatment did not significantly alter the ARR in pHPT patients but significantly reduced the ARR in PA patients. Diagnostic utility of ARR and its components for PA diagnostics under MR blocker treatment warrants further study.

A RANDOMIZED DOUBLE-BLIND PLACEBO-CONTROL PILOT STUDY OF EPLERENONE FOR THE TREATMENT OF CENTRAL SEROUS CHORIORETINOPATHY (ECSELSIOR).

PURPOSE: To evaluate the safety and effects of oral eplerenone in chronic central serous chorioretinopathy. METHODS: Prospective, randomized, double-blind, placebo-control study at a tertiary referral academic private practice. For a diagnosis of chronic central serous chorioretinopathy, patients must have had at least 3 months clinical follow-up demonstrating persistent symptoms, subfoveal fluid on spectral-domain optical coherence tomography, and <50% reduction in fluid thickness. Patients were randomized 2:1 (treatment:placebo) to receive eplerenone (25 mg daily for 1 week, then up to 50 mg daily for 8 weeks) or placebo once daily. RESULTS: Fifteen patients completed the study. Ten patients (15 eyes) were randomized into the eplerenone treatment arm, while the remaining 5 patients (6 eyes) received placebo. After 9 weeks of eplerenone therapy, mean logarithm of the minimal angle of resolution visual acuity improved from 0.394 (Snellen equivalent: 20/50) to 0.330 (20/43, P = 0.04). In the placebo group, the mean logarithm of the minimal angle of resolution visual acuity slightly decreased from 0.313 (20/41) to 0.342 (20/44) during the same period (P = 0.21). With respect to anatomic changes, mean maximal subretinal fluid height in the eplerenone group improved from 139.3 µm at baseline to 51.8 µm (P = 0.02), mean subfoveal fluid height improved from 121.4 µm to 29.4 µm (P = 0.01), and mean central subfield thickness improved from 366.2 µm to 283.7 µm (P = 0.02). In comparison with the placebo group, mean maximal subretinal fluid height worsened from 135.9 µm to 172.3 µm (P = 0.32), mean subfoveal fluid height worsened from 92.1 µm to 134.0 µm (P = 0.54), and mean central subfield thickness worsened from 345.0 µm to 380.0 µm (P = 0.37). No patients in either group experienced serious adverse events to result in treatment discontinuation. CONCLUSION: These findings suggest that oral eplerenone therapy is safe and potentially effective in the treatment of chronic central serous chorioretinopathy with persistent subretinal fluid.

Treatment of Unruptured Cerebral Aneurysms with the Mineralocorticoid Receptor Blocker Eplerenone-Pilot Study.

BACKGROUND: Currently there are no pharmacological therapies for patients with unruptured cerebral aneurysms. Elsewhere we showed that the mineralocorticoid receptor antagonist eplerenone prevented the formation of cerebral aneurysms in our ovariectomized hypertensive aneurysm rat model. The current pilot study evaluated whether it can be used to prevent the growth and rupture of cerebral aneurysms in hypertensive patients. METHODS: Between August 2011 and May 2014, we enrolled 82 patients with 90 aneurysms in an open-label uncontrolled clinical trial. All provided prior informed consent for inclusion in this study, and all were treated with eplerenone (25-100 mg/d). The primary end points of our study were the rupture and enlargement of the cerebral aneurysms. RESULTS: Of the 82 patients, 80 (88 unruptured aneurysms) were followed for a mean of 21.3 months (153.4 aneurysm-years); 12 patients (15.0%) permanently discontinued taking the drug. One month after the start of eplerenone administration and throughout the follow-up period, eplerenone kept the blood pressure within the normal range. Most notably, no aneurysms smaller than 9 mm ruptured or enlarged. However, of 2 large thrombosed aneurysms, 1 enlarged and the other ruptured. The overall annual rupture rate was .65%; it was 13.16% for aneurysms larger than 10 mm; the overall annual rate for reaching the primary end points was 1.30%. CONCLUSION: Our observations suggest that eplerenone may help to prevent the growth and rupture of unruptured cerebral aneurysms smaller than 9 mm. To assess its potential long-term clinical benefits, large clinical trials are needed.

Gene expression effects of glucocorticoid and mineralocorticoid receptor agonists and antagonists on normal human skeletal muscle.

Mineralocorticoid and glucocorticoid receptors are closely related steroid hormone receptors that regulate gene expression through many of the same hormone response elements. However, their transcriptional activities and effects in skeletal muscles are largely unknown. We recently identified mineralocorticoid receptors (MR) in skeletal muscles after finding that combined treatment with the angiotensin-converting enzyme inhibitor lisinopril and MR antagonist spironolactone was therapeutic in Duchenne muscular dystrophy mouse models. The glucocorticoid receptor (GR) agonist prednisolone is the current standard-of-care treatment for Duchenne muscular dystrophy because it prolongs ambulation, likely due to its anti-inflammatory effects. However, data on whether glucocorticoids have a beneficial or detrimental direct effect on skeletal muscle are controversial. Here, we begin to define the gene expression profiles in normal differentiated human skeletal muscle myotubes treated with MR and GR agonists and antagonists. The MR agonist aldosterone and GR agonist prednisolone had highly overlapping gene expression profiles, supporting the notion that prednisolone acts as both a GR and MR agonist that may have detrimental effects on skeletal muscles. Co-incubations with aldosterone plus either nonspecific or selective MR antagonists, spironolactone or eplerenone, resulted in similar numbers of gene expression changes, suggesting that both drugs can block MR activation to a similar extent. Eplerenone treatment alone decreased a number of important muscle-specific genes. This information may be used to develop biomarkers to monitor clinical efficacy of MR antagonists or GR agonists in muscular dystrophy, develop a temporally coordinated treatment with both drugs, or identify novel therapeutics with more specific downstream targets.

Aldosterone Upregulates Transient Receptor Potential Melastatin 7 (TRPM7).

Transient receptor potential melastatin 7 (TRPM7) is a ubiquitously expressed Mg(2+)-permeable ion channel fused to a C-terminal α-kinase domain. Recently, aldosterone was shown to increase intracellular Mg(2+) levels and alter inflammatory signaling in TRPM7-expressing HEK293 cells. This study was undertaken to assess whether these effects were related to an aldosterone-mediated increase of TRPM7 current and/or plasma membrane localization. Using HEK293 cells stably expressing WT-TRPM7, we found that 18-h application of aldosterone significantly increased TRPM7 current and TRPM7 plasma membrane protein expression by 48% and 34%, respectively. The aldosterone-mediated increase of TRPM7 current was inhibited by eplerenone, a mineralocorticoid receptor (MR) blocker, and GSK-650394, an inhibitor of the serum- and glucocorticoid-regulated kinase 1 (SGK1). SGK1 blockade also prevented the aldosterone-induced increase of TRPM7 plasma membrane protein. It was further determined that K1648R-TRPM7, the phosphotransferase-inactive TRPM7 mutant, was unresponsive to aldosterone. Therefore, chronic aldosterone treatment increases the plasma membrane expression of TRPM7, which is associated with an increase of TRPM7 current. This process occurs via an MR-dependent, genomic signaling cascade involving SGK1 and a functioning TRPM7 α-kinase domain. We suggest that this mechanism may be of general relevance when interpreting the effects of aldosterone because the MR receptor is found in multiple tissues, and TRPM7 and SGK1 are ubiquitously expressed.

Cortisol Induces Reactive Oxygen Species Through a Membrane Glucocorticoid Receptor in Rainbow Trout Myotubes.

Cortisol is an essential regulator of neuroendocrine stress responses in teleosts. Cortisol predominantly affects target tissues through the genomic pathway, which involves interacting with cytoplasmic glucocorticoid receptors, and thereby, modulating stress-response gene expressions. Cortisol also produces rapid effects via non-genomic pathways, which do not involve gene transcription. Although cortisol-mediated genomic pathways are well documented in teleosts, non-genomic pathways are not fully understood. Moreover, no studies have focused on the contribution of non-genomic cortisol pathways in compensatory stress responses in fish. In this study, rainbow trout (Oncorhynchus mykiss) skeletal myotubes were stimulated with physiological concentrations of cortisol and cortisol-BSA, a membrane-impermeable agent, resulting in an early induction of reactive oxygen species (ROS). This production was not suppressed by transcription or translation inhibitors, suggesting non-genomic pathway involvement. Moreover, myotube preincubation with RU486 and NAC completely suppressed cortisol- and cortisol-BSA-induced ROS production. Subcellular fractionation analysis revealed the presence of cell membrane glucocorticoid receptors. Finally, cortisol-BSA induced a significant increase in ERK1/2 and CREB phosphorylation, as well as in CREB-dependent transcriptional activation of the pgc1a gene expression. The obtained results strongly suggest that cortisol acts through a non-genomic glucocorticoid receptor-mediated pathway to induce ROS production and contribute to ERK/CREB/PGC1-α signaling pathway activation as stress compensation mechanisms. J. Cell. Biochem. 118: 718-725, 2017. © 2016 Wiley Periodicals, Inc.

Mineralocorticoid receptor antagonists attenuate exaggerated exercise pressor reflex responses in hypertensive rats.

Exaggerated heart rate (HR) and blood pressure responses to exercise in hypertension are mediated, in part, by overactivity of the exercise pressor reflex (EPR). The mechanisms underlying this EPR dysfunction have not been fully elucidated. Previous studies have shown that stimulation of mineralocorticoid receptors (MRs) with exogenous administration of aldosterone in normal, healthy rats reproduces the EPR overactivity characteristic of hypertensive animals. Conversely, the purpose of this study was to examine whether antagonizing MR with spironolactone (SPIR) or eplerenone (EPL) in decerebrated hypertensive rats ameliorates abnormal EPR function. Changes in mean arterial pressure (MAP) and HR induced by EPR or muscle mechanoreflex (a component of EPR) activation were assessed in normotensive Wistar-Kyoto rats and spontaneously hypertensive rats (SHRs) fed normal chow (NC) or a customized diet containing either SPIR or EPL for 3 wk. SHRs treated with SPIR or EPL had significantly attenuated MAP responses to EPR (NC: 45 ± 7 mmHg, SPIR: 26 ± 4 mmHg, and EPL: 24 ± 5 mmHg, P = 0.02) and mechanoreflex (NC: 34 ± 9 mmHg, SPIR: 17 ± 3 mmHg, and EPL: 15 ± 3 mmHg, P = 0.03) activation. SHRs treated with SPIR or EPL also showed significantly attenuated HR responses to EPR (NC: 17 ± 3 beats/min, SPIR: 9 ± 1 beats/min, and EPL: 9 ± 2 beats/min, P = 0.01) and mechanoreflex (NC: 15 ± 3 beats/min, SPIR: 6 ± 1 beats/min, and EPL: 7 ± 1 beats/min, P = 0.01) activation. Wistar-Kyoto rats treated with SPIR did not demonstrate significant differences in MAP or HR responses to EPR or mechanoreflex activation. The data suggest that antagonizing MRs may be an effective strategy for the treatment of EPR overactivity in hypertension.NEW & NOTEWORTHY Exaggerated cardiovascular responses to exercise in hypertensive patients are linked with overactive exercise pressor reflexes (EPRs). Administration of low-dose mineralocorticoid receptor antagonists (spironolactone or eplerenone) effectively ameliorates abnormal EPR function in hypertension. Effective treatment of EPR overactivity may reduce the cardiovascular risks associated with physical activity in hypertension.

Nonsteroidal mineralocorticoid antagonists in diabetic kidney disease.

PURPOSE OF REVIEW: Current data highlight the pathological aspects of excess aldosterone in promoting glomerular hypertrophy, glomerulosclerosis, and proteinuria in diabetic kidney disease (DKD). The role of nonsteroidal mineralocorticoid receptor antagonists (MRAs) in DKD is being evaluated in ongoing clinical trials. RECENT FINDINGS: Recent studies demonstrate beneficial effects of adding MRAs to the treatment regimen of patients with type 2 diabetes with nephropathy. The MRAs spironolactone and eplerenone can protect against organ damage caused by elevated levels of serum aldosterone in patients with heart failure and DKD but are limited by their side effects, for example, hyperkalemia. Finerenone is more selective for the mineralocorticoid receptor than spironolactone and has greater affinity for the mineralocorticoid receptor than eplerenone. It reduces the concentration of aldosterone without causing significant elevation in serum potassium. SUMMARY: MRAs have a clear role in reducing albuminuria when used with other renin-angiotensin system blockers in DKD; however, hyperkalemia limits their use. This article provides an overview of clinical studies with a novel MRA, finerenone, and several nonsteroidal MRAs being studied for treatment in DKD.

Eplerenone Prevents Atrial Fibrosis via the TGF-ß Signaling Pathway.

OBJECTIVES: Eplerenone (EPL), an antagonist of the mineralocorticoid receptor, is beneficial for atrial fibrillation and atrial fibrosis. However, the underlying mechanism remains less well known. We aimed to investigate the effect of EPL on atrial fibrosis using a mouse with selective atrial fibrosis and to explore the underlying mechanisms. METHODS: EPL-treated MHC-TGFcys33ser transgenic mice that have selective atrial fibrosis (Tx+EPL mice), as well as control mice, were used for in vivo studies including histological analyses, Western blotting, and qRT-PCR studies. TGF-ß1-stimulated atrial fibroblasts were treated with EPL or vehicle for the in vitro studies including Western blotting and qRT-PCR studies. In addition, Smad7 siRNA was used to knock down Smad7. RESULTS: EPL inhibited atrial fibrosis in the Tx mice. In addition, EPL suppressed the expression of fibrosis-related molecules induced by TGF-ß1 in vivo and in vitro. This occurred in concert with a downregulation of Smad7 protein expression and an upregulation of p-Smad2/3 protein expression. In addition, knockdown of Smad7 by siRNA abolished the protective roles of EPL. CONCLUSIONS: EPL inhibited atrial fibrosis in Tx mice. The underlying mechanism may involve increased protein expression of Smad7, which enhances the inhibitory feedback regulation of TGF-ß1/Smad signaling.

Signal Enhancement in the HPLC-ESI-MS/MS analysis of spironolactone and its metabolites using HFIP and NH4F as eluent additives.

This paper describes an LC-MS/MS method to determine the concentration of spironolactone and its metabolites 7-alpha-methylthiospironolactone and canrenone in blood plasma samples. The resulting assay is simple (using protein precipitation for sample preparation) and sensitive (the lower limit of quantification is close to 0.5 ng/ml) while requiring only 50 µl of plasma, making it especially suitable for analyzing samples obtained from pediatric and neonatal patients where sample sizes are limited. The sensitivity is achieved by using ammonium fluoride as an eluent additive, which in our case amplifies the signal from our analytes in the plasma solution on average about 70 times. The method is fully validated according to the European Medicines Agency's guideline and used for the measurement of pediatric patients' samples in clinical trials for evaluating oral spironolactone's and its metabolites' pharmacokinetics in children up to 2 years of age.

Eplerenone might affect atrial fibrosis in patients with hypertension.

BACKGROUND: Eplerenone is reported to reduce the development of atrial fibrillation (AF). The aim of this study was to clarify the mechanism of eplerenone for AF prevention from the viewpoint of P wave morphology, which is reported to correlate with atrial fibrosis. METHODS: Thirty-five patients with hypertension, who were randomized to receive eplerenone (n = 16) or amlodipine (n = 19) for 1 year, were evaluated. P wave signal-averaged electrocardiography was recorded at baseline and 1 year after entry, and P wave duration (Ad) and P wave dispersion (P-disp) were obtained. Serum levels of intact procollagen type I N-terminal propeptide (PINP) and N-terminal procollagen-III peptide (PIIIP) were also measured. RESULTS: There were no significant differences in baseline clinical characteristics including Ad, P-disp, and the decrease in blood pressure at 1-year follow-up between the two groups. Ad and P-disp (mean ± standard deviation) significantly increased in patients on amlodipine after 1 year (140 ± 21 ms to 139 ± 19 ms vs 132 ± 10 ms to 136 ± 12 ms, P < 0.01 and 14 ± 7 ms to 9 ± 4 ms vs 12 ± 5 to 16 ± 8, P < 0.01, respectively). PINP was significantly more decreased in patients with eplerenone than amlodipine (56.6 ± 30.4 µg/mL to 46.6 ± 19.4 µg/mL vs 41.5 ± 16.2 µg/L to 48.7 ± 21.3 µg/L, P < 0.01). Percent changes of Ad, P-disp, PINP, and PIIIP were significantly smaller in patients with eplerenone than amlodipine (0.0 ± 4.7% vs 3.2 ± 4.4%, P < 0.05, - 28.6 ± 31.0% vs 46.3 ± 73.0%, P < 0.01, - 5.6 ± 38.1% vs 22.7 ± 42.7%, P < 0.05, and - 9.2 ± 25.1% vs 7.4 ± 19.0%, P < 0.05, respectively). CONCLUSIONS: Eplerenone reduced the increase of Ad and P-disp with a decrease of PINP and PIIIP, which might translate into reduction of atrial fibrosis. This study showed that eplerenone may be useful as upstream therapy for AF in patients with hypertension.