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Obesity impairs endothelial-mediated vasodilation, the earliest step in vascular disease and a contributor to hypertension. We previously demonstrated that endothelial cell mineralocorticoid receptor (MR) deletion prevents obesity-induced microvascular dysfunction in females by increasing nitric oxide-mediated vasodilation. Estrogen receptor alpha (ERα) can oppose MR function, therefore we hypothesized that ERα mediates the benefits of endothelial MR deficiency. Females lacking endothelial MR or wildtype littermates were fed control or high fat diet for 20 weeks to cause obesity. MR deletion improved mesenteric artery endothelial-dependent vasodilation in obese females and ERα inhibition ex vivo negated this protective effect. Endothelial MR deletion results in significantly more ERα mRNA and protein. In vitro, estrogen increases endothelial nitric oxide synthase phosphorylation, which is inhibited by aldosterone and dependent on MR. Both proteins co-immunoprecipitate with striatin and a mimetic peptide that disrupts ERα-striatin binding also decreased MR-striatin interaction. Finally, removing endothelial MR in obese females restored endothelial function by increasing the nitric oxide component of vasodilation. Combined deletion of endothelial ERα negated the benefit of endothelial MR deletion. These results indicate that endothelial ERα prevents the detrimental effects of MR in obesity by increasing nitric oxide to rescue vasodilation in females. MR and ERα may compete for striatin binding within endothelial cells to regulate nitric oxide. These data identify a novel mechanism that promotes MR antagonism to prevent obesity-induced microvascular dysfunction in females.

The recent demonstration of the significant reduction in mortality in patients with septic shock treated with adjunctive glucocorticoids combined with fludrocortisone and the effectiveness of angiotensin II in treating vasodilatory shock have renewed interest in the role of the mineralocorticoid axis in critical illness. Glucocorticoids have variable interactions at the mineralocorticoid receptor. Similarly, mineralocorticoid receptor–aldosterone interactions differ from mineralocorticoid receptor–glucocorticoid interactions and predicate receptor–ligand interactions that differ with respect to cellular effects. Hyperreninemic hypoaldosteronism or selective hypoaldosteronism, an impaired adrenal response to increasing renin levels, occurs in a subgroup of hemodynamically unstable critically ill patients. The suggestion is that there is a defect at the level of the adrenal zona glomerulosa associated with a high mortality rate that may represent an adaptive response aimed at increasing cortisol levels. Furthermore, cross-talk exists between angiotensin II and aldosterone, which needs to be considered when employing therapeutic strategies.

Background Recent emerging evidence suggests that extra-adrenal synthesis of aldosterone occurs (e.g., within the failing heart and in certain brain areas). In this study, the authors investigated evidence for a local endogenous aldosterone production through its key processing enzyme aldosterone synthase within peripheral nociceptive neurons. Methods In male Wistar rats (n = 5 to 8 per group) with Freund’s complete adjuvant hind paw inflammation, the authors examined aldosterone, aldosterone synthase, and mineralocorticoid receptor expression in peripheral sensory neurons using quantitative reverse transcriptase–polymerase chain reaction, Western blot, immunohistochemistry, and immunoprecipitation. Moreover, the authors explored the nociceptive behavioral changes after selective mineralocorticoid receptor antagonist, canrenoate-K, or specific aldosterone synthase inhibitor application. Results In rats with Freund’s complete adjuvant–induced hind paw inflammation subcutaneous and intrathecal application of mineralocorticoid receptor antagonist, canrenoate-K, rapidly and dose-dependently attenuated nociceptive behavior (94 and 48% reduction in mean paw pressure thresholds, respectively), suggesting a tonic activation of neuronal mineralocorticoid receptors by an endogenous ligand. Indeed, aldosterone immunoreactivity was abundant in peptidergic nociceptive neurons of dorsal root ganglia and colocalized predominantly with its processing enzyme aldosterone synthase and mineralocorticoid receptors. Moreover, aldosterone and its synthesizing enzyme were significantly upregulated in peripheral sensory neurons under inflammatory conditions. The membrane mineralocorticoid receptor consistently coimmunoprecipitated with endogenous aldosterone, confirming a functional link between mineralocorticoid receptors and its endogenous ligand. Importantly, inhibition of endogenous aldosterone production in peripheral sensory neurons by a specific aldosterone synthase inhibitor attenuated nociceptive behavior after hind paw inflammation (a 32% reduction in paw pressure thresholds; inflammation, 47 ± 2 [mean ± SD] vs. inflammation + aldosterone synthase inhibitor, 62 ± 2). Conclusions Local production of aldosterone by its processing enzyme aldosterone synthase within peripheral sensory neurons contributes to ongoing mechanical hypersensitivity during local inflammation via intrinsic activation of neuronal mineralocorticoid receptors. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

Mineralocorticoid receptors (MRs) are implicated in the pathology of hypertension. MR blockers are recommended for the treatment of salt-sensitive or resistant hypertension. However, use of currently available MR blockers is limited by adverse events. This phase 3 multicenter, randomized, double-blind study compared the efficacy and safety of esaxerenone, a new selective nonsteroidal MR blocker, at 2.5 and 5 mg/day and eplerenone 50 mg/day in Japanese patients with essential hypertension. After a 4-week washout period, 1001 eligible adults with hypertension were randomized evenly to esaxerenone 2.5 or 5 mg/day or eplerenone 50 mg/day treatments, taken orally once daily for 12 weeks. Primary end points were changes in sitting systolic or diastolic blood pressure (BP) from baseline at the end of treatment. Esaxerenone 2.5 mg/day was noninferior to eplerenone for reductions in sitting and 24-hour BP. Reductions in BP with esaxerenone 5 mg/day were significantly greater than those with esaxerenone 2.5 mg/day. Changes in diurnal BP showed persistent 24-hour antihypertensive effects in all treatment groups. The proportions of patients achieving target sitting BP ( Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT02890173.

Objectives: Men are disproportionately affected by the coronavirus disease-2019 (COVID-19) and experience higher mortality as compared to women. Endothelial dysfunction has been proposed as a major inciting factor of pro-inflammatory and thrombotic changes in COVID-19 infection. The vascular effects of androgen signaling and inflammatory cytokines in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-mediated endothelial damage are not defined. Methods: Here, we determined the effects of SARS-CoV-2 spike protein-mediated endothelial damage under conditions of exposure to androgens and TNF-α. We tested the therapeutic effects of approved drugs: angiotensin receptor blockade by valsartan and mineralocorticoid receptor antagonism by spironolactone. Circulating endothelial injury markers VCAM-1 and E-selectin were measured in the plasma from men and women diagnosed with COVID-19. Results: Exposure of endothelial cells (ECs) in vitro to androgen dihydrotestosterone (DHT) exacerbated spike protein S1-mediated endothelial injury transcripts for cell adhesion molecules E-selectin, VCAM-1, and ICAM-1 and anti-fibrinolytic PAI-1 (P Conclusions: Androgen exposure promoted spike protein-mediated endothelial injury by increasing markers of inflammation and thrombosis. A beneficial therapeutic effect of the FDA-approved drug spironolactone was observed, supporting a rationale for further evaluation as an adjunct treatment in COVID-19.

INTRODUCTION AND OBJECTIVE:Abiraterone acetate (AA) has proven survival benefit for patients with metastatic hormone sensitive prostate cancer (mHSPC) and metastatic castrate resistant prostate can...

Objective: MR (mineralocorticoid receptor) activation is associated with cardiovascular ischemia in humans. This study explores the role of the MR in atherosclerotic mice of both sexes and identifies a sex-specific role for endothelial cell (EC)-MR in vascular inflammation. Approach and Results: In the AAV-PCSK9 (adeno-associated virus-proprotein convertase subtilisin/kexin type 9) mouse atherosclerosis model, MR inhibition attenuated vascular inflammation in males but not females. Further studies comparing male and female littermates with intact MR or EC-MR deletion revealed that although EC-MR deletion did not affect plaque size in either sex, it reduced aortic arch inflammation specifically in male mice as measured by flow cytometry. Moreover, MR-intact females had larger plaques but were protected from vascular inflammation compared with males. Intravital microscopy of the mesenteric vasculature demonstrated that EC-MR deletion attenuated TNFα (tumor necrosis factor α)-induced leukocyte slow rolling and adhesion in males, while females exhibited fewer leukocyte-endothelial interactions with no additional effect of EC-MR deletion. These effects corresponded with decreased TNFα-induced expression of the endothelial adhesion molecules ICAM-1 (intercellular adhesion molecule-1) and E-selectin in males with EC-MR deletion compared with MR-intact males and females of both genotypes. These observations were also consistent with MR and estrogen regulation of ICAM-1 transcription and E-selectin expression in primary cultured mouse ECs and human umbilical vein ECs. Conclusions: In male mice, EC-MR deletion attenuates leukocyte-endothelial interactions, plaque inflammation, and expression of E-selectin and ICAM-1, providing a potential mechanism by which the MR promotes vascular inflammation. In females, plaque inflammation and leukocyte-endothelial interactions are decreased relative to males and EC-MR deletion is not protective.

Background:Adaptive immunity is crucial in cardiovascular and renal inflammation/fibrosis upon hyperactivation of mineralocorticoid receptor. We have previously demonstrated that dendritic cells can respond to mineralocorticoid receptor activation, and the neutrophil gelatinase-associated lipocalin (NGAL) in dendritic cells is highly increased during aldosterone (Aldo)/mineralocorticoid receptor-dependent cardiovascular damage. However, the interrelationship among dendritic cells, target organs inflammation/fibrosis induced by mineralocorticoid receptor, and NGAL-dependence remains unknown.Objective:We studied the role of dendritic cells in mineralocorticoid receptor-dependent tissue remodeling and whether NGAL can modulate the inflammatory response of dendritic cells after mineralocorticoid receptor activation.Methods:Cardiovascular and renal remodeling induced by Aldo and high-salt diet [nephrectomy-Aldo-salt (NAS) model] were analyzed in CD11c.DOG mice, a model which allows dendritic cells ablation by using diphtheria toxin. In addition, in-vitro studies in NGAL-knock out dendritic cells were performed to determine the immunomodulatory role of NGAL upon Aldo treatment.Results:The ablation of dendritic cells prevented the development of cardiac hypertrophy, perivascular fibrosis, and the overexpression of NGAL, brain natriuretic peptide, and two profibrotic factors induced by NAS: collagen 1A1 and connective tissue growth factor. We determined that dendritic cells were not required to prevent renal hypertrophy/fibrosis induced by NAS. Between different immune cells analyzed, we observed that NGAL abundance was higher in antigen-presenting cells, while in-vitro studies showed that mineralocorticoid receptor stimulation in dendritic cells favored NGAL and IL-23 expression (p19 and p40 subunits), which are involved in the development of fibrosis and the Th17-driven response, respectively.Conclusion:NGAL produced by dendritic cells may play a pivotal role in the activation of adaptive immunity that leads to cardiovascular fibrosis during mineralocorticoids excess. © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Aldosterone is an important mineralocorticoid responsible for fluid and electrolyte homeostasis produced by aldosterone synthase (CYP11B2). An aldosterone synthase inhibitor (ASI) may be a therapeutic option for primary aldosteronism-related conditions such as resistant hypertension. An ASI with sufficient selectivity for CYP11B2 versus the similar cortisol-producing enzyme CYP11B1 has remained elusive. PB6440 is a novel ASI that is potent and highly selective for CYP11B2. In vitro studies demonstrated 200-300-fold selectivity of PB6440 for human CYP11B2 compared to human CYP11B1. In single and multiple dose cynomolgus monkey studies of orally administered PB6440, dose-and concentration-dependent reduction of plasma aldosterone after ACTH challenge was observed with >90% reduction at higher doses. Consistent with its high selectivity, PB6440 had little effect on the CYP11B1 cortisol pathway. Plasma levels of cortisol, 11-deoxycortisol, and deoxycorticosterone, remained unchanged even at high doses of PB6440. Systolic and diastolic blood pressure was reduced in a dose-dependent manner. Circulating half-life of PB6440 was approximately 17 hours with high oral bioavailability. In summary, PB6440 is a highly selective ASI that demonstrated sustained aldosterone suppression for 14 days with no effect on the CYP11B1 pathway in non-human primates. In single and multiple dose studies, PB6440 appeared well tolerated, demonstrating good oral bioavailability, and a PK profile supportive of once daily dosing. These results suggest that PB6440 may be useful in humans as a novel therapeutic for treating hypertension or other conditions caused by excess aldosterone.

Introduction: Neutrophil Gelatinase-Associated Lipocalin (NGAL) (or lipocalin 2) is a novel mineralocorticoid biotarget in the cardiovascular system. NGAL is also described as an acute renal lesion biomarker and NGAL serum concentration is associated with the severity of renal damages patients with a chronic kidney disease (CKD). Lipocalin2 (Lcn2) gene invalidation in a CKD mouse model protects from proteinuria and renal lesions. Objective: We hypothesized that the NGAL from macrophages promotes expression of chemoattractant molecules involved in renal lesions induced by mineralocorticoid excess. Methods: The role of Lcn2 was analyzed using full Lcn2 knock out mice (NGAL KO) challenged with uni-Nephrectomy, Aldosterone 200μg/kg/day, Salt 1% (NAS model) during 6 weeks. Assessment of CCL5/IL4 in kidney fibrosis were studied using maraviroc administration (50mg/kg/d in chow diet) or by injections of anti-IL4 antibody (600μg/week). Results: NAS induced a significant increase in the expression (relative values, mean±SEM, compared to 1 in the control samples, p&lt0.05) of extracellular matrix proteins such as collagen I (2.35±0.33), α-SMA (2.04±0.44) and fibronectin (3.38±0.42) in the kidney of WT mice associated with interstitial kidney fibrosis (6.49±0.70). These modifications were fully prevented by NGAL deletion. Expression of macrophages markers F4/80 , CD80 and CD86 was increased (5.11±0.46, 4.84±0.19 and 5.22±0.45 respectively) in WT NAS mice and partly prevented in NGAL KO mice. Macrophages isolated from NGAL KO or WT mice were co-treated with aldosterone (10 -8 M) and NaCl (40mM). In WT macrophages, expression of Lcn2 (2.81±0.30) and the CCL5 chemokine (2.48±0.32) was increased. The increase of CCL5 was prevented in NGAL KO macrophages. Such as total deletion of NGAL, CCL5 receptor blockade improved renal fibrosis and high level of Th2 CD4 + cell markers induced by NAS. Neutralization of IL4 Th2 cytokine in NAS mice injected with anti-IL4 antibody blunted kidney fibrosis and overexpression of profibrotic proteins such as collagen I, α-SMA and fibronectin. Conclusion: NGAL produced by macrophages plays a critical role in renal interstitial fibrosis through CCL5/IL4 pathways in mice exposed to mineralocorticoid excess.

We examined whether fingolimod (FTY720), an S1PR (sphingosine-1-phosphate receptor) modulator, has beneficial or harmful effects on mineralocorticoid/salt-induced renal injury. Uninephrectomized rats on 0.9% NaCl/0.3% KCl drinking solution were randomly divided into control, control+FTY720, deoxycorticosterone acetate (DOCA), and DOCA+FTY720 groups and administered vehicle, vehicle+FTY720, DOCA+vehicle, and DOCA+FTY720 for 4 weeks, respectively. Only the DOCA+FTY720 group had reduced survival rates and showed hemolysis because of intravascular mechanical fragmentation of erythrocytes and thrombocytopenia. Both the DOCA+FTY720 and DOCA groups developed malignant hypertension, which was more severe in the DOCA+FTY720 group. In the DOCA+FTY720 group only, thrombotic microangiopathy involving severe renal arteriole endothelial cell injury was observed and was characterized by fibrinoid necrosis and onion-skin lesions in arterioles. There were fewer circulating endothelial progenitor cells in the DOCA+FTY720 group but more in the DOCA group compared with the control group. Expression levels of VEGF (vascular endothelial growth factor), S1PR1, and S1PR3 in renal arteriole endothelial cells were significantly greater in the DOCA+FTY720 and DOCA groups compared with the control group, with levels being similar between the 2 groups. Expression levels of endothelial nitric oxide synthase in renal arteriole endothelial cells were significantly lower in the DOCA+FTY720 group only. The control+FTY720 group showed reduced circulating endothelial progenitor cells but no significant functional or pathological changes in kidneys or changes in blood pressure. Exposure of uninephrectomized rats to DOCA/salt+FTY720 for 4 weeks induced renal arteriolar endothelial cell injury, resulting in the development of thrombotic microangiopathy. Consideration of this possibility is recommended when prescribing FTY720.

Background In naive rats, corticosteroids activate neuronal membrane–bound glucocorticoid and mineralocorticoid receptors in spinal cord and periphery to modulate nociceptive behavior by nongenomic mechanisms. Here we investigated inflammation-induced changes in neuronal versus glial glucocorticoid and mineralocorticoid receptors and their ligand-mediated nongenomic impact on mechanical nociception in rats. Methods In Wistar rats (n = 5 to 7/group) with Freund’s complete adjuvant hind paw inflammation, we examined glucocorticoid and mineralocorticoid receptor expression in spinal cord and peripheral sensory neurons versus glial using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), Western blot, immunohistochemistry, and radioligand binding. Moreover, we explored the expression of mineralocorticoid receptors protecting enzyme 11-betahydroxysteroid dehydrogenase type 2 as well as the nociceptive behavioral changes after glucocorticoid and mineralocorticoid receptors agonist or antagonist application. Results Hind paw inflammation resulted in significant upregulation of glucocorticoid receptors in nociceptive neurons of spinal cord (60%) and dorsal root ganglia (15%) as well as mineralocorticoid receptors, while corticosteroid plasma concentrations remained unchanged. Mineralocorticoid (83 ± 16 fmol/mg) but not glucocorticoid (104 ± 20 fmol/mg) membrane binding sites increased twofold in dorsal root ganglia concomitant with upregulated 11-betahydroxysteroid dehydrogenase type 2 (43%). Glucocorticoid and mineralocorticoid receptor expression in spinal microglia and astrocytes was small. Importantly, glucocorticoid receptor agonist dexamethasone or mineralocorticoid receptor antagonist canrenoate-K rapidly and dose-dependently attenuated nociceptive behavior. Isobolographic analysis of the combination of both drugs showed subadditive but not synergistic or additive effects. Conclusions The enhanced mechanical sensitivity of inflamed hind paws accompanied with corticosteroid receptor upregulation in spinal and peripheral sensory neurons was attenuated immediately after glucocorticoid receptor agonist and mineralocorticoid receptor antagonist administration, suggesting acute nongenomic effects consistent with detected membrane-bound corticosteroid receptors.

Rationale: Resistant hypertension is a major health concern with unknown cause. Spironolactone is an effective antihypertensive drug, especially for patients with resistant hypertension, and is considered by the World Health Organization as an essential medication. Although spironolactone can act at the mineralocorticoid receptor (MR; NR3C2), there is increasing evidence of MR-independent effects of spironolactone. Objective: Here, we detail the unexpected discovery that Panx1 (pannexin 1) channels could be a relevant in vivo target of spironolactone. Methods and Results: First, we identified spironolactone as a potent inhibitor of Panx1 in an unbiased small molecule screen, which was confirmed by electrophysiological analysis. Next, spironolactone inhibited α-adrenergic vasoconstriction in arterioles from mice and hypertensive humans, an effect dependent on smooth muscle Panx1, but independent of the MR NR3C2. Last, spironolactone acutely lowered blood pressure, which was dependent on smooth muscle cell expression of Panx1 and independent of NR3C2. This effect, however, was restricted to steroidal MR antagonists as a nonsteroidal MR antagonist failed to reduced blood pressure. Conclusions: These data suggest new therapeutic modalities for resistant hypertension based on Panx1 inhibition.

Aldosterone, the primary mineralocorticoid, is synthesized in the outer zone of the adrenal cortex called the zona glomerulosa (ZG). The production of aldosterone is tightly regulated by angiotensin II (Ang II) and circulating potassium levels.1 Physiologically, aldosterone plays a key role in the maintenance of intravascular volume and blood pressure through sodium retention in the kidney. Excess aldosterone causes hypertension and induces cardiovascular complications.2–5 The autonomous secretion of aldosterone, independent of Ang II and sodium status, is known as primary aldosteronism (PA). PA is the most common cause of endocrine-related hypertension with a prevalence of 5% to 10% in hypertensive population6–10 and ≈20% in resistant hypertension.11–13 Because of the increased risk for cardiovascular complications in patients with PA, early detection of the disease and targeted treatment is recommended.14 The molecular pathogenesis of PA was largely unknown until recently. The development of specific antibodies against aldosterone synthase (CYP11B2), which is required for the final steps of aldosterone production, has allowed the detection of aldosterone-producing cells in resected adrenals.15,16 Using these antibodies, non-neoplastic foci of CYP11B2-expressing cells called aldosterone-producing cell clusters (APCC)15 have been identified in adrenal tissues adjacent to aldosterone-producing adenomas (APA) and in normal human adrenal glands without tumor or hyperplasia.15–20 Studies have shown that APCC are a common occurrence in normal human adrenals.21–23 Because circulating renin and Ang II levels are suppressed in patients with PA, the observation of APCC adjacent to APA suggested that APCC may represent a source of autonomous and renin-independent aldosterone secretion, perhaps even a precursor to APA.24 Over the past 6 years, somatic and germline mutations that cause inappropriate aldosterone production have been identified in patients with PA. Most of the mutations …

Vascular mineralocorticoid receptors play a role in vascular tone and blood pressure regulation, might participate in the pathophysiology of circulatory failure during sepsis, and represent a potential therapeutic target in this disease. We aimed to study the effects of mineralocorticoids and the involvement of vascular mineralocorticoid receptors in murine endotoxic and human septic shock.Experimental study.Translational investigation including animal research and in vitro experiments using human vascular cells and plasma from septic patients.Adult male C57Black 6 mice, adult patients with septic shock.Mice were injected with lipopolysaccharide and/or aldosterone. Human endothelial and smooth muscle cells were treated with pro-inflammatory cytokines with or without aldosterone, nuclear factor-κB inhibitor BAY 11-7082, or plasma from septic patients.Aldosterone improved 5-day survival, invasive arterial pressure, and in vivo and ex vivo arterial response to phenylephrine at 18 hours after induction of murine endotoxic shock. Both α1-adrenoceptor and mineralocorticoid receptor expressions studied in mouse aortas were down-regulated at 6 and 18 hours in endotoxemic mice and restored in aldosterone-treated mice. Furthermore, tumor necrosis factor-α decreased both mineralocorticoid receptor and α1-adrenoceptor expressions within 5 hours in human vascular cells in a nuclear factor-κB pathway-dependent manner. Mineralocorticoid receptor expression was also blunted in human cells treated with plasma from septic patients.We found a beneficial effect of mineralocorticoids on survival, blood pressure, and vascular reactivity, associated with a restoration of α1-adrenoceptor expression in endotoxic shock. Furthermore, blunted vascular mineralocorticoid receptor expression might participate in hemodynamic failure during sepsis.

Genome-wide analysis of renal sodium-transporting system has identified specific variations of Mendelian hypertensive disorders, including HSD11B2 gene variants in apparent mineralocorticoid excess. However, these genetic variations in extrarenal tissue can be involved in developing hypertension, as demonstrated in former studies using global and brain-specific Hsd11b2 knockout rodents. To re-examine the importance of renal dysfunction on developing hypertension, we generated kidney-specific Hsd11b2 knockout mice. The knockout mice exhibited systemic hypertension, which was abolished by reducing salt intake, suggesting its salt-dependency. In addition, we detected an increase in renal membrane expressions of cleaved epithelial sodium channel-α and T53-phosphorylated Na + -Cl − cotransporter in the knockout mice. Acute intraperitoneal administration of amiloride-induced natriuresis and increased urinary sodium/potassium ratio more in the knockout mice compared with those in the wild-type control mice. Chronic administration of amiloride and high-KCl diet significantly decreased mean blood pressure in the knockout mice, which was accompanied with the correction of hypokalemia and the resultant decrease in Na + -Cl − cotransporter phosphorylation. Accordingly, a Na + -Cl − cotransporter blocker hydrochlorothiazide significantly decreased mean blood pressure in the knockout mice. Chronic administration of mineralocorticoid receptor antagonist spironolactone significantly decreased mean blood pressure of the knockout mice along with downregulation of cleaved epithelial sodium channel-α and phosphorylated Na + -Cl − cotransporter expression in the knockout kidney. Our data suggest that kidney-specific deficiency of 11β-HSD2 leads to salt-dependent hypertension, which is attributed to mineralocorticoid receptor–epithelial sodium channel–Na + -Cl − cotransporter activation in the kidney, and provides evidence that renal dysfunction is essential for developing the phenotype of apparent mineralocorticoid excess.

Obesity is a risk factor for endothelial dysfunction and hypertension in pregnancy. Our lab has demonstrated that obesity-associated hypertension in female animal models develops via leptin-mediated, aldosterone-induced endothelial dysfunction (ED). We also showed that female mice are more sensitive to leptin-induced aldosterone activation of endothelial mineralocorticoid receptors (ECMR) due to an endogenous sex-specific upregulation of ECMR in females. Our previous data demonstrates that endothelial progesterone receptor activation increases ECMR expression and that ECMR deletion protects female mice from obesity-associated, leptin-mediated ED. However, whether ECMR play a role in ED in pregnancy is unknown. Therefore, we hypothesized that high progesterone levels increase ECMR expression in pregnant mice and that ECMR deletion protects pregnant mice from obesity-associated, leptin-mediated ED. Endothelial cells were isolated from aorta of timed-pregnant Balb/C mice (gestation day (GD) 17) and assessed for ECMR expression via RT-PCR. ECMR mRNA expression increased 9.2±0.2-fold (*P

Introduction: Neutrophil Gelatinase-Associated Lipocalin (NGAL) (or lipocalin 2) is a novel mineralocorticoid biotarget in the cardiovascular system. NGAL is also described as an acute renal lesion biomarker and NGAL serum concentration is associated with the severity of renal damages patients with a chronic kidney disease (CKD). Lipocalin2 (Lcn2) gene invalidation in a CKD mouse model protects from proteinuria and renal lesions. Objective: Since the immune system is involved in renal inflammation and fibrosis process, we hypothesized that the production of NGAL/Lcn2 by immune cells plays an important role in the deleterious mineralocorticoid effects in the kidney. Methods: The role of Lcn2 produced by immune cells was analyzed using full Lcn2 knock out mice (Full KO) and mice depleted for Lcn2 in their immune cells by bone marrow transplantation (BMT lcn2 KO). These mice were challenged with uni-Nephrectomy, Aldosterone 200μg/kg/day, Salt 1% (NAS model) during 6 weeks. Results: NAS induced a significant increase in the expression (relative values, mean±SEM, compared to 1 in the control samples, p-8 M) and NaCl (40mM). In WT macrophages, mRNA expression (relative values, mean±SEM, compared to 1 in the control samples, p Conclusion: NGAL produced by immune cells plays a critical role in renal interstitial fibrosis and inflammation induced by mineralocorticoid excess. The role of RANTES/CCl5 in the renal NGAL-mineralocorticoid pathways is currently analyzed.

INTRODUCTION AND OBJECTIVES:A major target of aldosterone is the distal tubule of the kidney, acting through mineralocorticoid receptors (MRs) on the epithelial cells of the renal tubules. MRs have...

Distal tubular sodium retention is a potent driver of hypertension, and the thiazide–sensitive sodium-chloride cotransporter (NCC) has a key role in this process. In humans, factors regulating NCC are unclear, but in animal models, aldosterone is a potent regulator, possibly via effects on plasma potassium. We studied the effects of the mineralocorticoid fludrocortisone on the abundance of NCC and its phosphorylated form (pNCC) as well as WNK lysine deficient protein kinase 4 (WNK4) and STE20/SPS1–related, proline alanine–rich kinase (SPAK) in human urinary exosomes. We isolated exosomes from daily urine samples in 25 patients undergoing fludrocortisone suppression testing (100 μg every 6 hours for 4 days) to diagnose or exclude primary aldosteronism. Over the course of the test, NCC levels increased 3.68-fold (P

We investigated the role of angiotensin type 1a receptors (AGTR1a) in vascular injury induced by aldosterone activation of mineralocorticoid receptors in Agtr1a −/− and wild-type (WT) mice infused with aldosterone for 14 days while receiving 1% NaCl in drinking water. Aldosterone increased systolic blood pressure (BP) by ≈30 mm Hg in WT mice and ≈50 mm Hg in Agtr1a −/− mice. Aldosterone induced aortic and small artery remodeling, impaired endothelium-dependent relaxation in WT mice, and enhanced fibronectin and collagen deposition and vascular inflammation. None of these vascular effects were observed in Agtr1a −/− mice. Aldosterone effects were prevented by the AGTR1 antagonist losartan in WT mice. In contrast to aldosterone, norepinephrine caused similar BP increase and mesenteric artery remodeling in WT and Agtr1a −/− mice. Agtr1a −/− mice infused with aldosterone did not increase sodium excretion in response to a sodium chloride challenge, suggesting that sodium retention could contribute to the exaggerated BP rise induced by aldosterone. Agtr1a −/− mice had decreased mesenteric artery expression of the calcium-activated potassium channel Kcnmb1 , which may enhance myogenic tone and together with sodium retention, exacerbate BP responses to aldosterone/salt in Agtr1a −/− mice. We conclude that although aldosterone activation of mineralocorticoid receptors raises BP more in Agtr1a −/− mice, AGTR1a is required for mineralocorticoid receptor stimulation to induce vascular remodeling and inflammation and endothelial dysfunction.

Long-lasting devices releasing steroids have been approved recently for macular edema of various origins. Identification of the retina as a novel mineralo-sensitive tissue also raises new therapeutic options.Recently, the over activation of the mineralocorticoid receptor (MR) pathway has been shown to cause fluid accumulation in the retina, choroidal vasodilation, and to promote retinal neovascularization in hypoxic conditions. These findings indicate that MR antagonists could have beneficial effects in the treatment of retinal diseases. Central serous chorioretinopathy is a retinal disease associated with choroidal vasodilation and subretinal fluid that affects mostly men with type A personality and occurrence has been associated with steroid intake. In several independent studies, MR antagonists have shown beneficial effects, significantly reducing subretinal fluid in eyes of chronic central serous chorioretinopathy patients.The role of MR in retinal disorder is emerging and the potential association with psychological traits is considered. The place of MR antagonists for retinal diseases treatment is discussed.

Primary autonomic failure is characterized by disabling orthostatic hypotension, but at least half of these patients have paradoxical supine hypertension. Renin–angiotensin mechanisms were not initially thought to contribute to this hypertension because plasma renin activity is often undetectable in autonomic failure. Plasma aldosterone levels are normal, however, and we recently showed that plasma angiotensin II is elevated and acts at AT 1 (angiotensin type 1) receptors to contribute to hypertension in these patients. Because aldosterone and angiotensin II can also bind mineralocorticoid receptors to elevate blood pressure, we hypothesized that mineralocorticoid receptor activation plays a role in the hypertension of autonomic failure. To test this hypothesis, we determined the acute effects of the mineralocorticoid receptor antagonist eplerenone (50 mg, oral) versus placebo on supine blood pressure in a randomized, double-blind, crossover study. Medications were given at 8:00 pm with blood pressure recorded every 2 hours for 12 hours. Ten primary autonomic failure patients with supine hypertension completed this study (7 pure autonomic failure, 2 multiple system atrophy, 1 parkinson’s disease; 7 male; 70±2 years of age). Eplerenone maximally reduced supine systolic blood pressure by 32±6 mm Hg at 8 hours after administration (versus 8±10 mm Hg placebo, P =0.016), with no effect on nocturia (12-hour urine volume: 985±134 mL placebo versus 931±94 mL eplerenone, P =0.492; nocturnal weight loss: −1.19±0.15 kg placebo versus −1.18±0.15 kg eplerenone, P =0.766). These findings suggest that inappropriate mineralocorticoid receptor activation contributes to the hypertension of autonomic failure, likely independent of canonical mineralocorticoid effects, and provides rationale for use of eplerenone in these patients.

Excess aldosterone is an important contributor to hypertension and cardiovascular disease. Conversely, low circulating aldosterone causes salt wasting and hypotension. Aldosterone activates mineralocorticoid receptors (MRs) to increase epithelial sodium channel (ENaC) activity. However, aldosterone may also stimulate the thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC). Here, we generated mice in which MRs could be deleted along the nephron to test this hypothesis. These kidney-specific MR-knockout mice exhibited salt wasting, low BP, and hyperkalemia. Notably, we found evidence of deficient apical orientation and cleavage of ENaC, despite the salt wasting. Although these mice also exhibited deficient NCC activity, NCC could be stimulated by restricting dietary potassium, which also returned BP to control levels. Together, these results indicate that MRs regulate ENaC directly, but modulation of NCC is mediated by secondary changes in plasma potassium concentration. Electrolyte balance and BP seem to be determined, therefore, by a delicate interplay between direct and indirect mineralocorticoid actions in the distal nephron.

Glucocorticoid deficiency (GD) has been proposed as a key contributor to shock states, but the presence and role of acute mineralocorticoid deficiency may be of equal or greater significance. We sought to analyze the incidence and degree of acute mineralocorticoid deficiency and GD in an animal model of severe hemorrhage and shock.Fifty-seven swine underwent 35% volume-controlled hemorrhage followed by aortic cross-clamping for 50 minutes to induce truncal ischemia-reperfusion. Protocol-guided resuscitation was performed. Laboratory analysis included cortisol, aldosterone, and plasma renin activity. The aldosterone-to-renin ratio (ARR) was calculated at each time point, and changes were correlated to markers of perfusion.Mean baseline cortisol levels were 5.8 μg/dL. Following hemorrhage, there was a significant increase in mean cortisol to 9.2 μg/dL (p0.001). After 1 hour of reperfusion, there was no change in mean cortisol levels (9.8 μg/dL, p = 0.12). Mean baseline aldosterone was 13.3 pg/mL. Aldosterone levels before cross-clamp removal increased significantly to 115.1 pg/mL (p0.001) and then rapidly declined to 49.2 pg/mL (p0.001) after 1 hour of reperfusion. Conversely, baseline plasma renin activity was 0.75 ng/mL per hour and increased significantly before cross-clamp removal (1.8) and at 1 hour (8.9, both p0.001). The ARR at baseline was 96.1 and increased to 113.5 (p = 0.68) before cross-clamp removal but significantly declined following 1 hour of reperfusion to 7.6 (p0.001). Overall, this represented a 93% reduction in mean ARR following reperfusion. The degree of aldosterone deficiency correlated with degree of systemic shock as measured by arterial base deficit (r = 0.47, p = 0.04), while cortisol showed no correlation.Hemorrhagic shock with ischemia-reperfusion injury resulted in only modest impact on the glucocorticoid axis, but major dysfunction of the mineralocorticoid axis and severe hyperreninemic hypoaldosteronism. The degree of aldosterone deficiency may provide prognostic information or offer potential targets for pharmacologic intervention.Diagnostic study, level III.

We have read with interest the recent article by Good et al1 on the additional role of the antihypertensive drug spironolactone and also the accompanying editorial by Huke.2 Good et al1 propose that spironolactone at therapeutic plasma concentrations inhibits small artery smooth muscle cell pannexin-1 (Panx-1) channels preventing the action of α1-adrenoceptor–mediated vasoconstriction. This novel action would add to the well-accepted mechanism of action of spironolactone as an antagonist of mineralocorticoid receptors to lower blood pressure. This work builds on a paper from the same laboratory that originally reported that the antimalarial drug mefloquine selectively inhibited α1-adrenoceptor–mediated contraction of small arteries via inhibition of Panx-1 channels.3 Their proposed mechanism was that Panx-1 channels located on smooth muscle cells of small arteries, when open, allow the release of ATP that acts autocrine-like back on ATP P2X1 receptors that finally contract the smooth muscle.3 We have published a series of articles addressing this novel pannexin/ATP mechanism that is …

Patients with primary adrenal insufficiency (PAI) require increased doses of glucocorticoids and mineralocorticoids during stressors, such as surgery, trauma, and sepsis. Although current guidelines exist for dose adjustments in these situations, there is no accepted dosing regimen for patients with PAI participating in intensive endurance exercise. Given the extensive physiologic stress of events, such as marathons, triathlons, and similar events, it is likely that a "stress-dose" of adrenal replacement therapy will not only prevent adrenal crisis, but also improve performance. A 50-year-old male endurance athlete with known PAI reported severe fatigue, nausea, and malaise after competing in prior marathons and intensive endurance exercise. After supplementing with glucocorticoids and mineralocorticoids before competition, he experienced decreased symptoms and improved performance. To better care for these patients, further studies should be conducted to provide safe and effective glucocorticoid and mineralocorticoid dose adjustments before intensive endurance exercise.

Loss of mineralocorticoid receptor signaling selectively in cardiomyocytes can ameliorate cardiac fibrotic and inflammatory responses caused by excess mineralocorticoids. The aim of this study was to characterize the role of cardiomyocyte mineralocorticoid receptor signaling in ischemia–reperfusion injury and recovery and to identify a role of mineralocorticoid receptor modulation of cardiac function. Wild-type and cardiomyocyte mineralocorticoid receptor knockout mice (8 weeks) were uninephrectomized and maintained on (1) high salt (0.9% NaCl, 0.4% KCl) or (2) high salt plus deoxycorticosterone pellet (0.3 mg/d, 0.9% NaCl, 0.4% KCl). After 8 weeks of treatment, hearts were isolated and subjected to 20 minutes of global ischemia plus 45 minutes of reperfusion. Mineralocorticoid excess increased peak contracture during ischemia regardless of genotype. Recovery of left ventricular developed pressure and rates of contraction and relaxation post ischemia–reperfusion were greater in knockout versus wild-type hearts. The incidence of arrhythmic activity during early reperfusion was significantly higher in wild-type than in knockout hearts. Levels of autophosphorylated Ca 2+ /calmodulin protein kinase II (Thr287) were elevated in hearts from wild-type versus knockout mice and associated with increased sodium hydrogen exchanger-1 expression. These findings demonstrate that cardiomyocyte-specific mineralocorticoid receptor–dependent signaling contributes to electromechanical vulnerability in acute ischemia–reperfusion via a mechanism involving Ca 2+ /calmodulin protein kinase II activation in association with upstream alteration in expression regulation of the sodium hydrogen exchanger-1.

Na(+) transport in the renal distal convoluted tubule (DCT) by the thiazide-sensitive NaCl cotransporter (NCC) is a major determinant of total body Na(+) and BP. NCC-mediated transport is stimulated by aldosterone, the dominant regulator of chronic Na(+) homeostasis, but the mechanism is controversial. Transport may also be affected by epithelial remodeling, which occurs in the DCT in response to chronic perturbations in electrolyte homeostasis. Hsd11b2(-/-) mice, which lack the enzyme 11β-hydroxysteroid dehydrogenase type 2 (11βHSD2) and thus exhibit the syndrome of apparent mineralocorticoid excess, provided an ideal model in which to investigate the potential for DCT hypertrophy to contribute to Na(+) retention in a hypertensive condition. The DCTs of Hsd11b2(-/-) mice exhibited hypertrophy and hyperplasia and the kidneys expressed higher levels of total and phosphorylated NCC compared with those of wild-type mice. However, the striking structural and molecular phenotypes were not associated with an increase in the natriuretic effect of thiazide. In wild-type mice, Hsd11b2 mRNA was detected in some tubule segments expressing Slc12a3, but 11βHSD2 and NCC did not colocalize at the protein level. Thus, the phosphorylation status of NCC may not necessarily equate to its activity in vivo, and the structural remodeling of the DCT in the knockout mouse may not be a direct consequence of aberrant corticosteroid signaling in DCT cells. These observations suggest that the conventional concept of mineralocorticoid signaling in the DCT should be revised to recognize the complexity of NCC regulation by corticosteroids.

Cardiac and renal diseases remain major challenges for healthcare systems in developed countries and commonly coexist, with a disorder in the heart or kidney often leading to secondary dysfunction or injury in the other organ. Indeed, the term cardiorenal syndrome has been introduced to describe the broad spectrum of disease involving both the heart and kidneys.1 Aldosterone is a steroid hormone with mineralocorticoid activity, produced primarily in the glomerular zone of the adrenal cortex.2 Aldosterone fulfills its major physiological function of maintaining sodium and potassium balance and blood pressure control by binding to the mineralocorticoid receptor (MR) in the connecting tubule and cortical collecting duct in the kidneys, thereby increasing sodium reabsorption and potassium secretion. There is a growing body of evidence for a broader role of aldosterone and MR activation in the pathophysiology of cardiovascular and renal disease.3,4 This article focuses on our knowledge and understanding of the direct roles of aldosterone and MR activation in the heart and kidneys, including common pathophysiological mechanisms in both organs and implications for clinical use of MR antagonists (MRAs) in the treatment of cardiac and renal diseases. MR expression has been demonstrated in vivo in vascular endothelial cells and vascular smooth muscle cells of interlobar arteries in mouse kidneys and ex vivo in cultured podocytes, mesangial cells, and renal fibroblasts.3 The MR is also expressed in multiple cell types in the heart, including cardiomyocytes, coronary endothelial and vascular smooth muscle cells, fibroblasts, and inflammatory cells, such as macrophages.5 Aldosterone and the glucocorticoid cortisol bind to the MR with similar affinities. Plasma concentrations of glucocorticoids are 100- to 1000-fold higher than those of aldosterone. Overstimulation of the MR is prevented by the coexpression of 11β-hydroxysteroid dehydrogenase type 2 (11-BHSD2). This enzyme converts cortisol into cortisone, which …

A central role for the kidney among the systems contributing to BP regulation and the development of hypertension has been proposed. Both the aldosterone/mineralocorticoid receptor pathway and the renal sympathetic nervous system have important roles in the regulation of renal excretory function and BP control, but the mechanisms underlying these processes have remained unclear. However, recent studies revealed the activation of two pathways in salt-sensitive hypertension. Notably, Rac1, a member of the Rho-family of small GTP binding proteins, was identified as a novel ligand-independent modulator of mineralocorticoid receptor activity. Furthermore, these studies point to crucial roles for the Rac1–mineralocorticoid receptor–NCC/ENaC and the renal β-adrenergic stimulant–glucocorticoid receptor–WNK4-NCC pathways in certain rodent models of salt-sensitive hypertension. The nuclear mineralocorticoid and glucocorticoid receptors may contribute to impaired renal excretory function and the resulting salt-sensitive hypertension by increasing sodium reabsorption at different tubular segments. This review provides an in-depth discussion of the evidence supporting these conclusions and considers the significance with regard to treating salt-sensitive hypertension and salt-induced cardiorenal injury.

Objective— Vascular remodeling occurs after endothelial injury, resulting in smooth muscle cell (SMC) proliferation and vascular fibrosis. We previously demonstrated that the blood pressure–regulating hormone aldosterone enhances vascular remodeling in mice at sites of endothelial injury in a placental growth factor–dependent manner. We now test the hypothesis that SMC mineralocorticoid receptors (MRs) directly mediate the remodeling effects of aldosterone and further explore the mechanism. Approach and Results— A wire-induced carotid injury model was performed in wild-type mice and mice with inducible SMC-specific deletion of the MR. Aldosterone did not affect re-endothelialization after injury in wild-type mice. Deletion of SMC-MR prevented the 79% increase in SMC proliferation induced by aldosterone after injury in MR-Intact littermates. Moreover, both injury-induced and aldosterone-enhanced vascular fibrosis were attenuated in SMC-specific MR knockout mice. Further exploration of the mechanism revealed that aldosterone-induced vascular remodeling is prevented by in vivo blockade of the placental growth factor–specific receptor, type 1 vascular endothelial growth factor receptor (VEGFR1), the receptor for placental growth factor. Immunohistochemistry of carotid vessels shows that the induction of VEGFR1 expression in SMC after vascular injury is attenuated by 72% in SMC-specific MR knockout mice. Moreover, aldosterone induction of vascular placental growth factor mRNA expression and protein release are also prevented in vessels lacking SMC-MR. Conclusions— These studies reveal that SMC-MR is necessary for aldosterone-induced vascular remodeling independent of renal effects on blood pressure. SMC-MR contributes to induction of SMC VEGFR1 in the area of vascular injury and to aldosterone-enhanced vascular placental growth factor expression and hence the detrimental effects of aldosterone are prevented by VEGFR1 blockade. This study supports exploring MR antagonists and VEGFR1 blockade to prevent pathological vascular remodeling induced by aldosterone.

The inability of mineralocorticoid receptor (MR) blockade to reduce hypertension associated with high angiotensin (Ang) II suggests direct actions of Ang II to regulate tubular sodium reabsorption via the epithelial Na + channel (ENaC) in the aldosterone-sensitive distal nephron. We used freshly isolated aldosterone-sensitive distal nephron from mice to delineate the synergism and primacy between aldosterone and Ang II in controlling functional ENaC activity. Inhibition of MR specifically prevented the increased number of functionally active ENaC, but not ENaC open probability elicited by a low sodium diet. In contrast, we found no functional role of glucocorticoid receptors in the regulation of ENaC activity by dietary salt intake. Simultaneous inhibition of MR and Ang II type 1 receptors ameliorated the enhanced ENaC activity caused by low dietary salt intake and produced significantly greater natriuresis than either inhibitor alone. Chronic systemic Ang II infusion induced more than 2 times greater increase in ENaC activity than observed during dietary sodium restriction. Importantly, ENaC activity remained greatly above control levels during maximal MR inhibition. We conclude that during variations in dietary salt intake both aldosterone and Ang II contribute complementarily to the regulation of ENaC activity in the aldosterone-sensitive distal nephron. In contrast, in the setting of Ang II–dependent hypertension, ENaC activity is upregulated well above the physiological range and is not effectively suppressed by inhibition of the aldosterone–MR axis. This provides a mechanistic explanation for the resistance to MR inhibition that occurs in hypertensive subjects having elevated intrarenal Ang II levels.

Licorice is a US Food and Drug Administration approved food supplement present in various forms without strict policies to regulate its consumption and to prevent toxicity. It is widely utilized as a sweetener, a thirst quencher, in various candies and drinks, and has some medicinal applications. The health benefits of licorice are minor compared to the adverse outcomes of chronic use which is never justified nor recommended. The long-established belief among the community that licorice is a natural healthy substance free of side effects promotes its liberal consumption and predisposition to toxicity. This merits further nationwide education through different media types on the health hazards of chronic licorice intake and the tolerable upper limit of daily ingestion. The main mode of action is through inhibition of the enzyme 11-b-hydroxysteroid dehydrogenase, resulting in a mineralocorticoid effect. This aldosterone-like action is the basic principle for understanding its health benefits and the wide spectrum of adverse effects. Among the various complications associated with excess licorice intake, effects on the cardiovascular system are the most serious. Herein is a review of the various cardiovascular complications associated with licorice intake. I hope that this review will caution physicians, exposed patients, and manufacturing companies against the detrimental effects of licorice and impel the Food and Drug Administration to actively control the use of this substance. Cardiovasc Endocrinol 2:46–49 c 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Although elevated renin–angiotensin system activity and angiotensinergic signaling within the brain are required for hypertension, polydipsia, and increased metabolic rate induced by deoxycorticosterone acetate (DOCA)-salt, the contribution of specific receptor subtypes and brain nuclei mediating these responses remains poorly defined. We hypothesized that angiotensin type 1a receptors (AT 1a R) within the subfornical organ (SFO) mediate these responses. Transgenic mice carrying a conditional allele of the endogenous AT 1a R (AT 1a R flox ) were administered an adenovirus encoding Cre-recombinase and enhanced green fluorescent protein (eGFP) or adenovirus encoding eGFP alone into the lateral cerebral ventricle. Adenovirus encoding Cre-recombinase reduced AT 1a R mRNA and induced recombination in AT 1a R flox genomic DNA specifically in the SFO, without significant effect in the paraventricular or arcuate nuclei, and also induced SFO-specific recombination in ROSA TdTomato reporter mice. The effect of SFO-targeted ablation of endogenous AT 1a R was evaluated in AT 1a R flox mice at 3 time points: (1) baseline, (2) 1 week after virus injection but before DOCA-salt, and (3) after 3 weeks of DOCA-salt. DOCA-salt–treated mice with deletion of AT 1a R in SFO exhibited a blunted increase in arterial pressure. Increased sympathetic cardiac modulation and urine copeptin, a marker of vasopressin release, were both significantly reduced in DOCA-salt mice when AT 1a R was deleted in the SFO. Additionally, deletion of AT 1a R in the SFO significantly attenuated the polydipsia, polyuria, and sodium intake in response to DOCA-salt. Together, these data highlight the contribution of AT 1a R in the SFO to arterial pressure regulation potentially through changes on sympathetic cardiac modulation, vasopressin release, and hydromineral balance in the DOCA-salt model of hypertension.

High serum levels of aldosterone have been linked to the development of cardiac disease. In contrast, angiotensin (Ang)-(1-7) was extensively shown to possess cardioprotective effects, including the attenuation of cardiac dysfunction induced by excessive mineralocorticoid activation in vivo, suggesting possible interactions between these 2 molecules. Here, we investigated whether there is cross-talk between aldosterone and Ang-(1-7) and its functional consequences for calcium (Ca 2+ ) signaling in ventricular myocytes. Short-term effects of aldosterone on Ca 2+ transient were assessed in Fluo-4/AM-loaded myocytes. Confocal images showed that Ang-(1-7) had no effect on Ca 2+ transient parameters, whereas aldosterone increased the magnitude of the Ca 2+ transient. Quite unexpectedly, addition of Ang-(1-7) to aldosterone-treated myocytes further enhanced the amplitude of the Ca 2+ transient suggesting a synergistic effect of these molecules. Aldosterone action on Ca 2+ transient amplitude was mediated by protein kinase A, and was related to an increase in Ca 2+ current ( I Ca ) density. Both changes were not altered by Ang-(1-7). When cardiomyocytes were exposed to aldosterone, increased Ca 2+ spark rate was measured. Ang-(1-7) prevented this change. In addition, a NO synthase inhibitor restored the effect of aldosterone on Ca 2+ spark rate in Ang-(1-7)-treated myocytes and attenuated the synergistic effect of these 2 molecules on Ca 2+ transient. These results indicate that NO plays an important role in this cross-talk. Our results bring new perspectives in the understanding of how 2 prominent molecules with supposedly antagonist cardiac actions cross-talk to synergistically amplify Ca 2+ signals in cardiomyocytes.

Mineralocorticoid receptor antagonists (MRAs) are commonly used to reduce blood pressure, left-ventricular hypertrophy, and urinary albumin excretion in patients with essential hypertension or primary aldosteronism. Effects of MRAs on hypertensive organ damage seem to occur beyond what is expected from the mere reduction of blood pressure. This suggests that activation of the mineralocorticoid receptor plays a central role in the development of cardiac and renal abnormalities in hypertensive patients. However, broad use of classic MRAs such as spironolactone has been limited by significant incidence of gynecomastia and other sex-related adverse effects. To overcome these problems, new aldosterone blockers have been developed with different strategies that include use of nonsteroidal MRAs and inhibition of aldosterone synthesis. Both strategies have been designed to avoid the steroid receptor cross-reactivity of classic MRAs that accounts for most adverse effects. Moreover, inhibition of aldosterone synthesis could have an additional benefit due to blockade of the mineralocorticoid receptor-independent pathways that might account for some of the untoward effects of aldosterone. The new aldosterone blockers are currently having extensive preclinical evaluation, and one of these compounds has passed phase 2 trials showing promising results in patients with primary hypertension and primary aldosteronism. This narrative review summarizes the knowledge on the use of classic MRAs in hypertension and covers the evidence currently available on new aldosterone blockers.

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.

We have documented recently that bradykinin (BK) directly inhibits activity of the epithelial Na + channel (ENaC) via the bradykinin B2 receptor (B2R)-G q/11 -phospholipase C pathway. In this study, we took advantage of mice genetically engineered to lack bradykinin receptors (B1R, B2R −/− ) to probe a physiological role of BK cascade in regulation of ENaC in native tissue, aldosterone-sensitive distal nephron. Under normal sodium intake (0.32% Na + ), ENaC open probability ( P o ) was modestly elevated in B1R, B2R −/− mice compared with wild-type mice. This difference is augmented during elevated Na + intake (2.00% Na + ) and negated during Na + restriction (+ ). Saturation of systemic mineralocorticoid status with deoxycorticosterone acetate similarly increased ENaC activity in both mouse strains, suggesting that the effect of BK on ENaC is independent of aldosterone. It is accepted that angiotensin-converting enzyme represents the major pathway of BK degradation. Systemic inhibition of angiotensin-converting enzyme with captopril (30 mg/kg of body weight for 7 days) significantly decreases ENaC activity and P o in wild-type mice, but this effect is diminished in B1R, B2R −/− mice. At the cellular level, acute captopril (100 μmol/L) treatment sensitized BK signaling cascade and greatly potentiated the inhibitory effect of 100 nmol/L of BK on ENaC. We concluded that BK cascade has its own specific role in blunting ENaC activity, particularly under conditions of elevated sodium intake. Augmentation of BK signaling in the aldosterone-sensitive distal nephron inhibits ENaC-mediated Na + reabsorption, contributing to the natriuretic and antihypertensive effects of angiotensin-converting enzyme inhibition.

Reactive oxygen species are exacerbating factors in failing hearts. We examined whether spironolactone, a mineralocorticoid receptor antagonist, provides additional effects to olmesartan, an angiotensin II receptor blocker, on oxidative stress in postinfarct failing hearts. Congestive heart failure due to myocardial infarction (MI) was induced by the coronary artery ligation in rats. Three weeks later, the rats were divided into 4 groups: an untreated MI group, spironolactone (100 mg·kg·d)-treated MI group, olmesartan (10 mg·kg·d)-treated MI group, and combination-treated (spironolactone and olmesartan) MI group. After 7 weeks of MI, monotherapy improved left ventricular dilatation and function, and suppressed myocardial lipid peroxidation, in association with an attenuation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent and mitochondrial superoxide production. Moreover, combination therapy caused a synergistic improvement in these indices. In experiments using cultured myocytes, aldosterone (100 nmole/L) and angiotensin II (100 nmole/L) enhanced both sources of superoxide production, although these humoral factors affected NADPH oxidase subunits (p47phox and gp91phox) differently. In conclusion, aldosterone and angiotensin II increase NADPH oxidase-dependent and mitochondrial superoxide production in myocytes, and the combination of an angiotensin II receptor blocker and mineralocorticoid receptor antagonist has a synergistic attenuation of cardiac oxidative stress, leading to an improvement in cardiac function in postinfarct failing hearts.

The renin-angiotensin-aldosterone system is involved in the arterial hypertension-associated cardiovascular remodeling. In this context, the development of cardiac fibrosis results from an imbalance between profibrotic and antifibrotic pathways, in which the role of aldosterone is yet not established. To determine the role of intracardiac aldosterone in the development of myocardial fibrosis during hypertension, we used a double transgenic model (AS-Ren) of cardiac hyperaldosteronism (AS) and systemic hypertension (Ren). The 9-month–old hypertensive mice had cardiac fibrosis, and hyperaldosteronism enhanced the fibrotic level. The mRNA levels of connective tissue growth factor and transforming growth factor-β1 were similarly increased in Ren and AS-Ren mice compared with wild-type and AS mice, respectively. Hyperaldosteronism combined with hypertension favored the macrophage infiltration (CD68 + cells) in heart, and enhanced the mRNA level of monocyte chemoattractant protein 1, osteopontin, and galectin 3. Interestingly, in AS-Ren mice the hypertension-induced increase in bone morphogenetic protein 4 mRNA and protein levels was significantly inhibited, and B-type natriuretic peptide expression was blunted. The mineralocorticoid receptor antagonist eplerenone restored B-type natriuretic peptide and bone morphogenetic protein 4 levels and decreased CD68 and galectin 3 levels in AS-Ren mice. Finally, when hypertension was induced by angiotensin II infusion in wild-type and AS mice, the mRNA profiles did not differ from those observed in Ren and AS-Ren mice, respectively. The aldosterone-induced inhibition of B-type natriuretic peptide and bone morphogenetic protein 4 expression was confirmed in vitro in neonatal mouse cardiomyocytes. Altogether, we demonstrate that, at the cardiac level, hyperaldosteronism worsens hypertension-induced fibrosis through 2 mineralocorticoid receptor-dependent mechanisms, activation of inflammation/galectin 3–induced fibrosis and inhibition of antifibrotic factors (B-type natriuretic peptide and bone morphogenetic protein 4).

Mineralocorticoid receptor (MR) activation may be deleterious to the cardiovascular system, and MR antagonists improve morbidity and mortality of patients with heart failure. However, mineralocorticoid signaling in the heart remains largely unknown. Using a pan-genomic transcriptomic analysis, we identified neutrophil gelatinase-associated lipocalin (NGAL or lipocalin 2) as a strongly induced gene in the heart of mice with conditional and targeted MR overexpression in cardiomyocytes (whereas induction was low in glucocorticoid receptor–overexpressing mice). NGAL mRNA levels were enhanced after hormonal stimulation by the MR ligand aldosterone in cultured cardiac cells and in the heart of wild-type mice. Mineralocorticoid pathological challenge induced by nephrectomy/aldosterone/salt treatment upregulated NGAL expression in the heart and aorta and its plasma levels. We show evidence for MR binding to an NGAL promoter, providing a mechanism for NGAL regulation. We propose that NGAL may be a marker of mineralocorticoid-dependent injury in the cardiovascular system in mice.

Overactivation of the mineralocorticoid receptor signaling is implicated in cardiovascular disease, including hypertensive heart disease. Oxidative stress is suggested to augment mineralocorticoid receptor signal transduction, but the precise mechanisms remain unclear. Mineralocorticoid receptor activity is regulated by multiple factors, in addition to plasma ligand levels. We previously identified Rac1 GTPase as a modulator of mineralocorticoid receptor activity. Here we show that oxidative stress induces mineralocorticoid receptor activation in a ligand-independent, Rac1-depenent manner in cardiomyocytes. Oxidant stress was induced in rat cultured cardiomyocytes (H9c2) by l -buthionine sulfoximine (BSO), an inhibitor of glutathione synthesis. BSO depleted intracellular glutathione and concomitantly increased reactive oxygen species (199%; P P N -acetylcysteine. The ligand independency of BSO action was indicated using a mutant mineralocorticoid receptor that does not bind ligands. With this mutant mineralocorticoid receptor, BSO-evoked mineralocorticoid receptor activation remained intact, whereas ligand-induced mineralocorticoid receptor activation was abolished. We next examined the involvement of Rac1. BSO increased active Rac1 in a redox-dependent fashion, and Rac inhibition suppressed the enhancing effect of BSO. Constitutively active Rac1, indeed, potentiated mineralocorticoid receptor transactivation. Furthermore, mineralocorticoid receptor transactivation by BSO was accompanied by enhanced nuclear accumulation of mineralocorticoid receptor. We conclude that alteration of redox state modulates mineralocorticoid receptor–dependent transcriptional activity via Rac1 in the heart. This redox-sensitive, ligand-independent mineralocorticoid receptor activation may contribute to the processes by which oxidant stress promotes cardiac injury.

Background— We evaluated the effect of the selective mineralocorticoid receptor antagonist eplerenone on renal function and the interaction between changes in renal function and subsequent cardiovascular outcomes in patients with heart failure and left ventricular systolic dysfunction after an acute myocardial infarction in the Eplerenone Post–Acute Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS). Methods and Results— Serial changes in estimated glomerular filtration rate (eGFR) were available in 5792 patients during a 24-month follow-up. Patients assigned to eplerenone had a decline in eGFR with an adjusted mean difference of −1.4±0.3 mL · min −1 · 1.73 m −2 compared with placebo ( P −1 · 1.73 m −2 ) and persisted throughout the study. Overall, 914 patients experienced a decline in eGFR >20% in the first month, 16.9% and 14.7% in the eplerenone and placebo groups, respectively (odds ratio, 1.15; 95% confidence interval, 1.02–1.30; P =0.017). In multivariate analyses, determinants of this early decline in eGFR were female sex, age ≥65 years, smoking, left ventricular ejection fraction 20% was associated with worse cardiovascular outcomes independently of baseline eGFR and of the use of eplerenone, which retained its prognostic benefits even under these circumstances. Conclusions— In patients with heart failure after acute myocardial infarction and receiving standard medical care, an early decline in eGFR is not uncommon and is associated with poor long-term outcome. Eplerenone induced a moderately more frequent early decline in eGFR, which did not affect its clinical benefit on cardiovascular outcomes.

Corticosteroid regimens that stimulate both mineralocorticoid and glucocorticoid pathways consistently reverse vasopressor-dependent hypotension in septic shock but have variable effects on survival. The objective of this study was to determine whether exogenous mineralocorticoid and glucocorticoid treatments have distinct effects and whether the timing of administration alters their effects in septic shock. DESIGN, SETTING, SUBJECTS, AND INTERVENTIONS: Desoxycorticosterone, a selective mineralocorticoid agonist; dexamethasone, a selective glucocorticoid agonist; and placebo were administered either several days before (prophylactic) or immediately after (therapeutic) infectious challenge and continued for 96 hrs in 74 canines with staphylococcal pneumonia.Effects of desoxycorticosterone and dexamethasone were different and opposite depending on timing of administration for survival (p = .05); fluid requirements (p = .05); central venous pressures (p ≤ .007); indicators of hemoconcentration (i.e., sodium [p = .0004], albumin [p = .05], and platelet counts [p = .02]); interleukin-6 levels (p = .04); and cardiac dysfunction (p = .05). Prophylactic desoxycorticosterone treatment significantly improved survival, shock, and all the other outcomes stated, but therapeutic desoxycorticosterone did not. Conversely, prophylactic dexamethasone was much less effective for improving these outcomes compared with therapeutic dexamethasone with the exception of shock reversal. Prophylactic dexamethasone given before sepsis induction also significantly reduced serum aldosterone and cortisol levels and increased body temperature and lactate levels compared with therapeutic dexamethasone (p ≤ .05), consistent with adrenal suppression.In septic shock, mineralocorticoids are only beneficial if given prophylactically, whereas glucocorticoids are most beneficial when given close to the onset of infection. Prophylactic mineralocorticoids should be further investigated in patients at high risk to develop sepsis, whereas glucocorticoids should only be administered therapeutically to prevent adrenal suppression and worse outcomes.

Background— Extensive evidence implicates aldosterone excess in the development and progression of cardiovascular disease states including hypertension, metabolic syndrome, cardiac hypertrophy, heart failure, and cardiorenal fibrosis. Recent studies show that activation of inflammatory cascade may play a specific role in the sequelae of mineralocorticoid activation, although the linking mechanism remains unclear. We tested the possibility that secondary stimulation of the stromal-derived factor 1/CXC chemokine receptor 4 (SDF-1/CXCR4) pathway plays a contributory role. Methods and Results— We investigated the effect of the highly selective CXCR4 antagonist AMD3465 (6 mg/kg per day for 6 weeks through minipump) in dexoycorticosterone acetate (DOCA)-treated, uninephrectomized mice. CXCR4 antagonism significantly attenuated the induction of cardiac fibrosis, renal fibrosis, hypertension, and left ventricular hypertrophy by DOCA. Mineralocorticoid excess also stimulated the accumulation of T-lymphocytes in the heart and kidney and this was significantly blunted by CXCR4 inhibition. Conclusions— Taken together, these data strongly implicate the SDF-1/CXCR4 axis in the pathogenesis of mineralocorticoid excess induced hypertension, inflammation, and cardiorenal fibrosis. This insight provides a new potential therapeutic approach for the treatment of specific aspects of mineralocorticoid mediated cardiovascular disease.

Aldosterone influences independently the vascular environment in humans, acting through structural and functional modifications of the arterial wall as derived from mineralocorticoid receptors. In rats, aldosterone infusion increases arterial stiffness in the presence of high-sodium intake, together with development of extracellular matrix and inflammatory factors. A selective increase in systolic and pulse pressure ensues, causing predominant organ damage on the heart, kidney and large arteries. In humans at rest, but independently of mean arterial pressure, arterial stiffness and wave reflections are associated with a steeper increase in these parameters with age. This finding is observed mainly with the CC genotype and not the TT or the TC genotype of the aldosterone synthase gene polymorphism. Early identification of individuals presenting this genotype could be important to detect hypertension.

OBJECTIVE To assess the additional value of adrenal venous sampling (AVS) to diagnose primary aldosteronism sub-types in patients who have a unilateral nodule detected by computed tomography (CT scan) and who should undergo an adrenalectomy. METHODS A retrospective study to assess consecutive patients with primary aldosteronism undergoing an adrenal CT scan and AVS. Criterion for selective cannulation was an equal or higher cortisol level in the adrenal vein compared to the inferior vena cava. An adrenal-vein aldosterone-to-cortisol ratio of at least two times higher than the other side defined lateralization of aldosterone production. RESULTS Sixty-seven patients (mean age 52 years, 39 men) underwent a CT scan and AVS. In nine patients (13%), cannulation of the right adrenal vein led to a technical failure. Both procedures led to diagnosis of 29 patients with adenoma-producing aldosterone (APA; 50%), 23 bilateral adrenal hyperplasias (40%), and six unilateral adrenal hyperplasias (10%). Of the 45 patients with a nodule detected by CT, subsequent AVS showed bilateral secretion in 16 patients (36%). Compared to the strategy of coupling CT scans with AVS to diagnosis APA, a CT scan alone had an accuracy of 72.4% (P < 0.001). Among patients with a macronodule detected by CT, 13 (37%) had bilateral secretion as assessed by AVS. The patients with a macronodule detected by CT alone had the same risk of a discrepancy as those with a small nodule (P = 0.99). CONCLUSION AVS is essential to diagnose the unilateral hypersecretion of aldosterone, even in patients in whom a unilateral macronodule is detected by CT, to avoid unnecessary surgery.