Eplerenone Inhibits Atherosclerosis in Nonhuman Primates

Cardiovascular Dynamics in HIV: The Influence of Adrenal Function and Nutritional Status

This interdisciplinary review explores the intricate nexus between HIV infection, nutrition, adrenal gland function, and cardiovascular health, highlighting a critical aspect of HIV management often overlooked in current literature. With the advent of antiretroviral therapy, the life expectancy of people living with HIV has dramatically improved, transforming HIV into a manageable chronic condition. However, this success brings forth new challenges, notably an increased risk of cardiovascular diseases among people living with HIV. We examine the normal physiology of the adrenal gland, including its role in mineral metabolism, a crucial facet of nutrition. We discuss the evolution of knowledge tying adrenal pathology to cardiovascular disease. We explore the impact of HIV on adrenal gland findings from a gross pathology perspective, as well as the clinical impact of adrenal insufficiency in HIV. The review further elucidates the role of nutrition in this context, considering the double burden of undernutrition and obesity prevalent in regions heavily affected by HIV. By aggregating findings from longitudinal studies and recent clinical trials, the review presents compelling evidence of increased cardiovascular disease among people living with HIV compared with people without HIV. It highlights the critical role of the adrenal glands in regulating nutrient metabolism and its implications for cardiovascular health, drawing attention to the potential for dietary interventions and targeted therapies to mitigate these risks. This review urges a paradigm shift in the management of HIV, advocating for a holistic approach that incorporates nutritional assessment and interventions into routine HIV care to address the complex interplay between HIV, adrenal function, and cardiovascular health. Through this lens, we offer insights into novel therapeutic strategies aimed at reducing cardiovascular risk in people living with HIV, contributing to the ongoing efforts to enhance the quality of life and longevity in this population.

Effect of esaxerenone on ischaemia and reperfusion injury in rat hearts

OBJECTIVES

In myocardial infarction, the addition of mineralocorticoid receptor blockers to standard therapies, such as angiotensin-converting enzyme inhibitors or beta-blockers, reportedly reduces mortality and cardiac events. We investigated whether the non-steroidal mineralocorticoid receptor blocker esaxerenone has cardioprotective effects and its protective mechanisms.

METHODS

Isolated rat hearts were Langendorff-perfused (constant pressure, 80 mmHg) with oxygenated Krebs-Henseleit bicarbonate buffer and reperfused for 60 min; afterwards, recovery of function (left ventricular pressure, measured with an intraventricular balloon) and myocardial injury were measured. In a preliminary study, we determined the optimal concentration of esaxerenone required for myocardial protection. Next, esaxerenone was administered in the pre- and post-ischaemic phases to determine the optimal timing of administration. In addition, we assessed coronary flow response to acetylcholine with and without esaxerenone. We examined whether esaxerenone-induced cardioprotection was prevented by targeting putative components in the preconditioning manner (the mitochondrial ATP-sensitive potassium [KATP] channel).

RESULTS

Myocardial protection by esaxerenone was observed when esaxerenone was administered before ischaemia but not after ischaemia. The coronary flow response to acetylcholine was significantly better in the esaxerenone group than in the control group. The cardioprotective effect of esaxerenone was eliminated by the mitochondrial KATP channel blocker, 5-hydroxy decanoate.

CONCLUSIONS

This study confirmed the myocardial protective effect of the pre-ischaemic administration of esaxerenone. Esaxerenone may contribute to coronary endothelial protection and exert pharmacological preconditioning via the mitochondrial KATP channel.

To Explore the Key Active Compounds and Therapeutic Mechanism of Guizhi Gancao Decoction in Coronary Heart Disease by Network Pharmacology and Molecular Docking

Objective. Coronary heart disease (CHD) is the leading cause of death from cardiovascular disease and has become an important public health problem worldwide. Guizhi Gancao Decoction (GGD) has been shown to be used in the treatment of CHD with good efficacy, but its specific therapeutic mechanism and active ingredients have not been fully clarified. This study aims to identify the active compounds and key targets of GGD in the treatment of CHD, explore the therapeutic mechanism of GGD, and provide candidate compounds for anti-CHD drug development. Methods. The main compounds of GGD were determined by UPLC-MS/MS analysis and screened by SwissADME. The corresponding targets of GGD compounds were obtained from SwissTargetPrediction, and the targets of CHD were obtained from the HERB and GeneCards databases. The STRING 11.5 database was used to analyze the PPI (Protein-Protein Interactions) network of potential therapeutic targets of GGD compounds. Cytoscape 3.7.2 was used to construct target-related networks and find core targets. The GEO database was used to validate the differential expression of core targets. The PANTHER Classification System was used to functionally classify potential therapeutic targets for GGD. The GO biological process analysis and KEGG pathway analysis of targets were completed by DAVID 6.8 database. AutoDockTools 1.5.6 and PyMol 2.5.2 were used to perform molecular docking of core targets with the active GGD compounds. Results. 7 active GGD compounds were obtained based on UPLC-MS/MS and pharmacological parameter evaluation, which corresponded to 131 CHD-related targets. Among them, EGFR, MAPK3, RELA, CCND1, ESR1, PTGS2, NR3C1, CYP3A4, MMP9, and PTPN11 were considered core targets. According to the targets related to CHD, glycyrrhetinic acid, liquiritigenin, and schisandrin are considered key active ingredients. GO biological process and KEGG analysis indicated that the potential targets of GGD in the treatment of CHD involve a variety of biological processes and therapeutic mechanisms. Molecular docking results showed that both the core targets and the corresponding compounds had the good binding ability. Conclusions. This study contributes to a more comprehensive understanding of the therapeutic mechanism and active ingredients of GGD for CHD and provides candidate compounds for drug development of CHD.

A Selective Mineralocorticoid Receptor Blocker, Esaxerenone, Attenuates Vascular Dysfunction in Diabetic C57BL/6 Mice

AIMS

Pharmacological blockade of mineralocorticoid receptors (MRs) is a potential therapeutic approach to reduce cardiovascular complications since MRs play a crucial role in cardiovascular regulation. Recent studies suggest that MR antagonists affect several extrarenal tissues, including vessel function. We investigated the effect of a novel nonsteroidal selective MR blocker, esaxerenone, on diabetes-induced vascular dysfunction.

METHODS

Diabetes was induced by a single dose of streptozotocin in 8-week-old male C57BL/6 mice. Esaxerenone (3 mg/kg/day) or a vehicle was administered by gavage to diabetic mice for 3 weeks. Metabolic parameters, plasma aldosterone levels, and parameters related to renal function were measured. Endothelium-dependent or -independent vascular responses of the aortic segments were analyzed with acetylcholine or sodium nitroprusside, respectively. Human umbilical vein endothelial cells (HUVECs) were used for the in vitro study.

RESULTS

Induction of diabetes elevated plasma aldosterone level (P＜0.05) and impaired endothelium-dependent vascular relaxation (P＜0.05). The administration of esaxerenone ameliorated the endothelial dysfunction (P＜0.01) without the alteration of metabolic parameters, blood pressure, and renal function. Esaxerenone improved the eNOS^Ser1177 phosphorylation in the aorta obtained from diabetic mice (P＜0.05) compared with that in the vehicle-treated group. Furthermore, a major MR agonist, aldosterone, decreased eNOS^Ser1177 phosphorylation and increased eNOS^Thr495 phosphorylation in HUVECs, which recovered with esaxerenone. Esaxerenone ameliorated the endothelium-dependent vascular relaxation caused by aldosterone in the aortic segments obtained from C57BL/6 mice (P＜0.001).

CONCLUSION

Esaxerenone attenuates the development of diabetes-induced endothelial dysfunction in mice. These results suggest that esaxerenone has potential vascular protective effects in individuals with diabetes.

Diagnostic efficacy of intravascular ultrasound combined with Gd2O3-EPL contrast agent for patients with atherosclerosis

Atherosclerosis is a cardiovascular disease that is pathologically associated with the growth of atherosclerotic plaques and vascular vulnerability. Intravascular ultrasound (IVUS) has been used to evaluate and treat cardiovascular diseases. Accumulating evidence has demonstrated that Gd2O3-doped nanoparticles contrast can be applied for the diagnosis of human diseases. In the present study, eplerenone (EPL), a mineralocorticoid receptor antagonist, was first doped with Gd2O3 nanoparticles (Gd2O3-EPL), following which its diagnostic efficacy for use in IVUS measurements (Gd2O3-EPL-IVUS) was evaluated for patients suspected with atherosclerosis. Gd2O3-EPL-IVUS presented with higher accuracy and sensitivity compared with IVUS in diagnosing 188 patients with suspected atherosclerosis. Gd2O3-EPL-IVUS exhibited stronger signals associated with plaque morphology compared with aloe IVUS for patients with atherosclerosis. In addition, Gd2O3-EPL-IVUS application resulted in clearer arterial plaque images compared with IVUS by binding mineralocorticoid receptors. Atherosclerosis was subsequently confirmed in all patients using computerized tomography-coronary angiography. Gd2O3-EPL-IVUS showed more accuracy in measuring vessel size, plaque burden and minimal lumen area compared with IVUS analysis alone. In conclusion, these outcomes suggest that Gd2O3-EPL-IVUS is a reliable tool for the evaluation of coronary lesions in patients with atherosclerosis.

Novel Insights into the Crosstalk between Mineralocorticoid Receptor and G Protein-Coupled Receptors in Heart Adverse Remodeling and Disease

The mineralocorticoid hormone aldosterone regulates sodium and potassium homeostasis but also adversely modulates the maladaptive process of cardiac adverse remodeling post-myocardial infarction. Through activation of its mineralocorticoid receptor (MR), a classic steroid hormone receptor/transcription factor, aldosterone promotes inflammation and fibrosis of the heart, the vasculature, and the kidneys. This is why MR antagonists reduce morbidity and mortality of heart disease patients and are part of the mainstay pharmacotherapy of advanced human heart failure. A plethora of animal studies using cell type⁻specific targeting of the MR gene have established the importance of MR signaling and function in cardiac myocytes, vascular endothelial and smooth muscle cells, renal cells, and macrophages. In terms of its signaling properties, the MR is distinct from nuclear receptors in that it has, in reality, two physiological hormonal agonists: not only aldosterone but also cortisol. In fact, in several tissues, including in the myocardium, cortisol is the primary hormone activating the MR. There is a considerable amount of evidence indicating that the effects of the MR in each tissue expressing it depend on tissue- and ligand-specific engagement of molecular co-regulators that either activate or suppress its transcriptional activity. Identification of these co-regulators for every ligand that interacts with the MR in the heart (and in other tissues) is of utmost importance therapeutically, since it can not only help elucidate fully the pathophysiological ramifications of the cardiac MR's actions, but also help design and develop novel better MR antagonist drugs for heart disease therapy. Among the various proteins the MR interacts with are molecules involved in cardiac G protein-coupled receptor (GPCR) signaling. This results in a significant amount of crosstalk between GPCRs and the MR, which can affect the latter's activity dramatically in the heart and in other cardiovascular tissues. This review summarizes the current experimental evidence for this GPCR-MR crosstalk in the heart and discusses its pathophysiological implications for cardiac adverse remodeling as well as for heart disease therapy. Novel findings revealing non-conventional roles of GPCR signaling molecules, specifically of GPCR-kinase (GRK)-5, in cardiac MR regulation are also highlighted.

New Clinical Aspects of Eplerenone Use in Clinical Practice

The problem of the discrepancy between convincing evidences of the effectiveness of the use of mineralocorticoid receptor antagonists in patients with heart failure with reduced left ventricular ejection fraction and insufficiently frequent their use in clinical practice for the treatment of these patients is considered in the article. Experts opinions on the reasons for this discrepancy are also presented. New data on the effectiveness of the use of the mineralocorticoid receptor antagonist, eplerenone, in some clinical situations identified in the analysis of subgroups of participants in a large randomized clinical trial EMPHASIS-HF are discussed. The main goal of this study was to evaluate the efficacy of eplerenone compared with placebo in patients with heart failure and reduced left ventricular function. In addition, experimental animal studies, which may indicate the pleiotropic effects of eplerenone in patients with vascular diseases, are presented. The new data on the effectiveness of eplerenone in subgroups of patients with heart failure and certain characteristics may be an additional reason to draw the attention of physicians to the benefits of its use and, accordingly, its more frequent application in clinical practice for the treatment of patients with clear indications for this therapy.

No Significant Role for Smooth Muscle Cell Mineralocorticoid Receptors in Atherosclerosis in the Apolipoprotein-E Knockout Mouse Model

Objective: Elevated levels of the hormone aldosterone are associated with increased risk of myocardial infarction and stroke in humans and increased progression and inflammation of atherosclerotic plaques in animal models. Aldosterone acts through the mineralocorticoid receptor (MR) which is expressed in vascular smooth muscle cells (SMCs) where it promotes SMC calcification and chemokine secretion in vitro. The objective of this study is to explore the role of the MR specifically in SMCs in the progression of atherosclerosis and the associated vascular inflammation in vivo in the apolipoprotein E knockout (ApoE^−/−) mouse model.

Methods and Results: Male ApoE^−/− mice were bred with mice in which MR could be deleted specifically from SMCs by tamoxifen injection. The resulting atheroprone SMC-MR-KO mice were compared to their MR-Intact littermates after high fat diet (HFD) feeding for 8 or 16 weeks or normal diet for 12 months. Body weight, tail cuff blood pressure, heart and spleen weight, and serum levels of glucose, cholesterol, and aldosterone were measured for all mice at the end of the treatment period. Serial histologic sections of the aortic root were stained with Oil Red O to assess plaque size, lipid content, and necrotic core area; with PicroSirius Red for quantification of collagen content; by immunofluorescent staining with anti-Mac2/Galectin-3 and anti-smooth muscle α-actin antibodies to assess inflammation and SMC marker expression; and with Von Kossa stain to detect plaque calcification. In the 16-week HFD study, these analyses were also performed in sections from the brachiocephalic artery. Flow cytometry of cell suspensions derived from the aortic arch was also performed to quantify vascular inflammation after 8 and 16 weeks of HFD. Deletion of the MR specifically from SMCs did not significantly change plaque size, lipid content, necrotic core, collagen content, inflammatory staining, actin staining, or calcification, nor were there differences in the extent of vascular inflammation between MR-Intact and SMC-MR-KO mice in the three experiments.

Conclusion: SMC-MR does not directly contribute to the formation, progression, or inflammation of atherosclerotic plaques in the ApoE^−/− mouse model of atherosclerosis. This indicates that the MR in non-SMCs mediates the pro-atherogenic effects of MR activation.

Randomized, Placebo-Controlled Trial to Evaluate Effects of Eplerenone on Metabolic and Inflammatory Indices in HIV

CONTEXT

HIV-infected individuals demonstrate increased renin-angiotensin-aldosterone system activation in association with visceral adiposity, insulin resistance, and inflammation. A physiologically based treatment approach targeting mineralocorticoid receptor (MR) blockade may improve metabolic and inflammatory indices in HIV.

OBJECTIVE

To investigate effects of eplerenone on insulin sensitivity, inflammatory indices, and other metabolic parameters in HIV.

DESIGN

Six-month, double-blind, randomized, placebo-controlled trial.

SETTING

Academic clinical research center.

PARTICIPANTS

HIV-infected individuals with increased waist circumference and abnormal glucose homeostasis.

INTERVENTION

Eplerenone 50 mg or placebo daily.

OUTCOME

The primary end point was change in insulin sensitivity measured by the euglycemic-hyperinsulinemic clamp technique. Secondary end points included change in body composition and inflammatory markers.

RESULTS

Forty-six individuals were randomized to eplerenone (n = 25) vs placebo (n = 21). Eplerenone did not improve insulin sensitivity [0.48 (-1.28 to 1.48) vs 0.43 (-1.95 to 2.55) mg/min/μIU/mL insulin; P = 0.71, eplerenone vs placebo] when measured by the gold standard euglycemic-hyperinsulinemic clamp technique. Intramyocellular lipids (P = 0.04), monocyte chemoattractant protein-1 (P = 0.04), and high-density lipoprotein (P = 0.04) improved among those randomized to eplerenone vs placebo. Trends toward decreases in interleukin-6 (P = 0.10) and high-sensitivity C-reactive protein (P = 0.10) were also seen with eplerenone vs placebo. Plasma renin activity and aldosterone levels increased in the eplerenone vs placebo-treated group, demonstrating expected physiology. MR antagonism with eplerenone was well tolerated among the HIV population, with no considerable changes in blood pressure or potassium.

CONCLUSION

MR blockade may improve selected metabolic and inflammatory indices in HIV-infected individuals. Further studies are necessary to understand the clinical potential of MR antagonism in HIV.

Urotensin II promotes aldosterone expression in rat aortic adventitial fibroblasts

Urotensin II (UII) contributes to cardiovascular diseases by activating vasoactive peptides. The present study aimed to determine the effect of UII on aldosterone (ALD) and its receptor in cultured adventitial fibroblasts (AFs) and the tunica adventitia of rat vessels to explore the possible mechanisms underlying vascular remodeling. Expression levels of aldosterone and its receptor on tunica adventitia were determined using immunohistochemistry. Growth‑arrested AFs and tunica adventitia from rat vessels were incubated with UII and inhibitors of various signal transduction pathways. ALD receptor (ALD‑R) mRNA expression levels and ALD protein exoression levels were determined by reverse transcription‑quantitative polymerase chain reaction and ELISA, respectively. Aldosterone and its receptors were expressed on tunica adventitia. UII promoted ALD protein secretion from cells in a dose‑ and time‑dependent manner. ALD‑R mRNA expression in cells was also dysregulated. Furthermore, the effects of UII were substantially inhibited by treatment with the inhibitors PD98059, Y‑27632, H‑7, CSA and nicardipine. These results were further verified in the tunica adventitia of rat vessels. The present findings indicated that UII stimulated ALD protein secretion and ALD‑R mRNA expression in AFs and in the tunica adventitia of rat vessels; moreover, this effect may be mediated by signal transduction pathways involving MAPK, Rho, PKC, calcineurin and Ca2+. UII may also contribute to vascular remodeling by stimulating the production of ALD and its receptor.

Evidence for the use of mineralocorticoid receptor antagonists in the treatment of coronary artery disease and post-angioplasty restenosis

Mineralocorticoid receptor antagonists (MRAs), such as spironolactone and eplerenone have an established role in the treatment of heart failure. However, many experimental and clinical studies have shown that aldosterone also plays a pivotal role in a variety of other pathophysiological conditions within the cardiovascular system. Aldosterone has been suggested to promote inflammation, endothelial dysfunction and smooth muscle cell hyperplasia during the development of atherosclerosis, thereby promoting the development of coronary artery disease (CAD). Since CAD and subsequent ischemic cardiomyopathy are the major causes of heart failure, it is of major interest, whether pharmacological therapy with MRAs among heart failure patients will also affect the common underlying conditions, namely, atherosclerosis and subsequent coronary vessel narrowing/rarefication. Therefore, in this article, we reviewed and discussed the preclinical and clinical evidence of MRAs for the treatment of acute or chronic vascular remodeling processes, such as atherosclerosis and post-angioplasty restenosis, which determine the progression of CAD and subsequent ischemic cardiomyopathy.

The Role of the Mineralocorticoid Receptor in Inflammation: Focus on Kidney and Vasculature

BACKGROUND

The remarkable success of clinical trials in mineralocorticoid receptor (MR) inhibition in heart failure has driven research on the physiological and pathological role(s) of nonepithelial MR expression. MR is widely expressed in the cardiovascular system and is a major determinant of endothelial function, smooth muscle tone, vascular remodeling, fibrosis, and blood pressure. An important new dimension is the appreciation of the role MR plays in immune cells and target organ damage in the heart, kidney and vasculature, and in the development of insulin resistance.

SUMMARY

The mechanism for MR activation in tissue injury continues to evolve with the evidence to date suggesting that activation of MR results in a complex repertoire of effects involving both macrophages and T cells. MR is an important transcriptional regulator of macrophage phenotype and function. Another important feature of MR activation is that it can occur even with normal or low aldosterone levels in pathological conditions. Tissue-specific conditional models of MR expression in myeloid cells, endothelial cells, smooth muscle cells and cardiomyocytes have been very informative and have firmly demonstrated a critical role of MR as a key pathophysiologic variable in cardiac hypertrophy, transition to heart failure, adipose inflammation, and atherosclerosis. Finally, the central nervous system activation of MR in permeable regions of the blood-brain barrier may play a role in peripheral inflammation. Key Message: Ongoing clinical trials will help clarify the role of MR blockade in conditions, such as atherosclerosis and chronic kidney disease.

Mineralocorticoid Receptor Deficiency in Macrophages Inhibits Atherosclerosis by Affecting Foam Cell Formation and Efferocytosis

Mineralocorticoid receptor (MR) has been considered as a potential target for treating atherosclerosis. However, the cellular and molecular mechanisms are not completely understood. We aim to explore the functions and mechanisms of macrophage MR in atherosclerosis. Atherosclerosis-susceptible LDLRKO chimeric mice with bone marrow cells from floxed control mice or from myeloid MR knock-out (MRKO) mice were generated and fed with high cholesterol diet. Oil red O staining showed that MRKO decreased atherosclerotic lesion area in LDLRKO mice. In another mouse model of atherosclerosis, MRKO/APOEKO mice and floxed control/APOEKO mice were generated and treated with angiotensin II. Similarly, MRKO inhibited the atherosclerotic lesion area in APOEKO mice. Histological analysis showed that MRKO increased collagen coverage and decreased necrosis and macrophage accumulation in the lesions. In vitro results demonstrated that MRKO suppressed macrophage foam cell formation and up-regulated the expression of genes involved in cholesterol efflux. Furthermore, MRKO decreased accumulation of apoptotic cells and increased effective efferocytosis in atherosclerotic lesions. In vitro study further revealed that MRKO increased the phagocytic index of macrophages without affecting their apoptosis. In conclusion, MRKO reduces high cholesterol- or angiotensin II-induced atherosclerosis and favorably changes plaque composition, likely improving plaque stability. Mechanistically, MR deficiency suppresses macrophage foam cell formation and up-regulates expression of genes related to cholesterol efflux, as well as increases effective efferocytosis and phagocytic capacity of macrophages.

Modulation of the sympathetic nervous system by renal denervation prevents reduction of aortic distensibility in atherosclerosis prone ApoE-deficient rats

BACKGROUND

Apolipoprotein E-deficient (ApoE(-/-)) rodents spontaneously develop severe hypercholesterolemia and increased aortic stiffness, both accepted risk factors for cardiovascular morbidity and mortality in humans. In patients with resistant hypertension renal denervation (RDN) may improve arterial stiffness, however the underlying mechanisms are incompletely understood. This study investigates the impact of RDN on aortic compliance in a novel atherosclerosis prone ApoE(-/-)-rat model.

METHODS

Normotensive, 8 weeks old ApoE(-/-) and Sprague-Dawley (SD) rats were subjected to bilateral surgical RDN (n = 6 per group) or sham operation (n = 5 per group) and fed with normal chow for 8 weeks. Compliance of the ascending aorta was assessed by magnetic resonance imaging. Vasomotor function was measured by aortic ring tension recordings. Aortic collagen content was quantified histologically and plasma aldosterone levels were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

After 8 weeks, ApoE(-/-)-sham demonstrated a 58 % decrease in aortic distensibility when compared with SD-sham (0.0051 ± 0.0011 vs. 0.0126 ± 0.0023 1/mmHg; p = 0.02). This was accompanied by an impaired endothelium-dependent relaxation of aortic rings and an increase in aortic medial fibrosis (17.87 ± 1.4 vs. 12.27 ± 1.1 %; p = 0.006). In ApoE(-/-)-rats, RDN prevented the reduction of aortic distensibility (0.0128 ± 0.002 vs. 0.0051 ± 0.0011 1/mmHg; p = 0.01), attenuated endothelial dysfunction, and decreased aortic medial collagen content (12.71 ± 1.3 vs. 17.87 ± 1.4 %; p = 0.01) as well as plasma aldosterone levels (136.33 ± 6.6 vs. 75.52 ± 8.4 pg/ml; p = 0.0003). Cardiac function and metabolic parameters such as hypercholesterolemia were not influenced by RDN.

CONCLUSION

ApoE(-/-)-rats spontaneously develop impaired vascular compliance. RDN improves aortic distensibility and attenuated endothelial dysfunction in ApoE(-/-)-rats. This was associated with a reduction in aortic fibrosis formation, and plasma aldosterone levels.

Association of cardiac NT pro-β-type natriuretic peptide with metabolic and endothelial risk factors in young obese hypertensive patients: a perspective on the hypothalamic pituitary adrenal axis activation

BACKGROUND

In practice, there is increasing recognition of the importance of hypothalamic pituitary adrenal axis in the cardiovascular disease progression. The association of brain natriuretic peptide with obesity and characteristics of the metabolic syndrome in adults and aged patients is well established, but that in pediatrics needs thorough elucidation.

AIM

The aim of this study was to assess the association of hypothalamic pituitary adrenal axis mediators (cortisol and aldosterone) with plasma NT-pro β-type natriuretic peptide (NT-proBNP) levels on metabolic, immune-inflammatory and endothelial markers in young obese pediatric patients.

METHODS

This is achieved by recruitment of 60 young (13-17 years) obese pediatric cohorts who are further subclassified according to their stage of hypertension; normotensive, prehypertensive and hypertensive patients.

RESULTS

The study showed significant differences in the metabolic parameters (glucose, insulin and HOMA-index) among the three obese young patient groups. Levels of cortisol and aldosterone, as well as NT-proBNP levels are positively associated with characteristics of the metabolic syndrome; blood pressure, BMI, HOMA index in all three obese groups. However, their association to the lipid profile was insignificant. These increases aligned harmonically with the assessed immune-inflammatory markers; CRP, TNF-α, and IL-23, as well as levels of sICAM, sVCAM and p-selectin, reflecting the involvement of mast cells and inflammatory effects on the vascular endothelium. ROC analysis revealed their beneficial addition as promising biomarkers for a better prognostic profile of hypertension-induced cardiovascular risk.

CONCLUSION

Early detection of NT-proBNP, cortisol and aldosterone levels in pre-hypertension stage added to the immune-inflammatory mediators may improve the coronary risk assessment in young Egyptian patients.

Effect and mechanism of poly (ADP-ribose) polymerase-1 in aldosterone-induced apoptosis

The present study aimed to investigate the effects of aldosterone on vascular endothelial cells and the viability of poly (ADP-ribose) polymerase 1 (PARP1) in cells, and to examine the molecular mechanisms underlying the effects of aldosterone on vascular endothelial cell injury. Cultured endothelial cells were treated either with different concentrations of aldosterone for the same duration or with the same concentrations of aldosterone for different durations, and the levels of apoptosis and activity of PARP1 in the cells were detected, respectively. Aldosterone receptor antagonists or PARP1 inhibitors were added to cells during treatment with aldosterone and the levels of apoptosis and activity of PARP1 were detected. As the concentration of aldosterone increased or the treatment time increased, the number of apoptotic cells and the activity of PARP1 increased. The aldosterone receptor antagonists and PARP1 inhibitors inhibited the increase of apoptosis and PARP1 activity caused by aldosterone treatment. Aldosterone activated the activity of PARP1 via the aldosterone receptor, inhibiting cell proliferation and inducing apoptosis. Treatment with PARP1 may be used as a target for vascular diseases caused by aldosterone at high concentrations.

Renal denervation attenuates progression of atherosclerosis in apolipoprotein E-deficient mice independent of blood pressure lowering

The renal autonomic nervous system may contribute to hypertension and vascular disease. Although the effects of renal artery denervation on blood pressure lowering are controversial, there may be other beneficial vascular effects independent of blood pressure lowering. Bilateral renal denervation (RDN) or sham operation (SO) was performed in 14-week-old male apolipoprotein E-deficient mice on a Western diet starting at 10 weeks of age. Efficacy of RDN was confirmed by reduction of renal norepinephrine levels (SO: 3.8±0.1 versus RDN: 1.7±0.3 ng/mL; P<0.01) at 6 weeks after procedure. Compared with SO, RDN had no effect on blood pressure (SO: 101.0±2.4 versus RDN: 97.5±1.6 mm Hg; P=0.25), total cholesterol (SO: 536.7±28.5 versus RDN: 535.7±62.9 mg/dL; P=0.99), or triglycerides (SO: 83.7±3.5 versus RDN: 86.9±10.2 mg/dL; P=0.78). Quantification of atherosclerosis at 20 weeks of age demonstrated reduced atherosclerosis in mice receiving RDN compared with SO (arterial tree oil-red-O surface staining RDN: 4.2±0.5% versus SO: 6.3±0.7%; P<0.05). Reduced atherosclerosis was associated with increased smooth muscle cell content in atherosclerotic plaques (RDN: 13.3±2.1 versus SO: 8.1±0.6%; P<0.05). Serum levels of aldosterone, monocyte chemoattractant protein-1, and 8-isoprostane were lower in mice that received RDN compared with sham-operated mice (aldosterone; RDN: 206.8±33.2 versus SO: 405.5±59.4 pg/mL, P<0.05; monocyte chemoattractant protein-1; RDN: 51.7±7.9 versus SO: 91.71±4.6 pg/mL, P<0.05; 8-isoprostane; RDN: 331.9±38.2 versus SO: 468.5±42.0 pg/mL, P<0.05). RDN reduces progression of atherosclerosis in apolipoprotein E-deficient mice. These changes are associated with reduced aldosterone levels, monocyte chemoattractant protein-1, and markers of oxidative stress.

Role of mineralocorticoid receptor antagonists in cardiovascular disease

Aldosterone exerts its best known sodium homeostasis actions by controlling sodium excretion at the level of the distal tubules via activation of the apical epithelial sodium channel and the basolateral Na(+)/K(+)ATPase pump. Recently, this mineralocorticoid hormone has been demonstrated to act on the heart and blood vessels. Excess release of aldosterone in relation to the salt status induces both genomic and nongenomic effects that by promoting endothelial dysfunction, and vascular and cardiorenal adverse remodeling, contribute to the target organ damage found in hypertension, heart failure, myocardial infarction, and chronic renal failure. Mineralocorticoid receptor blockers have been shown to be highly effective in resistant hypertension and to slow down heart failure progression, and in experimental animals, the development of atherosclerosis. Blockade of the action of aldosterone and potentially other mineralocorticoid steroids has been increasingly demonstrated to be an extremely beneficial therapy in different forms of cardiovascular disease. This review provides a summary of the knowledge that exists on aldosterone actions in the cardiovascular system and, in providing the translational impact of this knowledge to the clinical arena, illustrates how much more needs to be achieved in exploring the use of mineralocorticoid receptor blockers in less advanced stages of heart, renal, and vascular disease.

Effects of Add-on Therapy Consisting of a Selective Mineralocorticoid Receptor Blocker on Arterial Stiffness in Patients with Uncontrolled Hypertension

OBJECTIVE

Aldosterone plays an important role in the pathogenesis of atherosclerosis; however, the significance of mineralocorticoid receptor blockade for atherosclerosis has not been fully elucidated. In this study, the effect of add-on eplerenone on the degree of arterial stiffness was examined in patients with uncontrolled hypertension.

METHODS

Forty-seven uncontrolled hypertensive patients who had previously been treated with anti-hypertensive drugs were examined retrospectively. Thirty-two patients received add-on therapy consisting of eplerenone (Group E) and 15 patients received add-on therapy with a Calcium channel blocker (CCB) or an increased dose of CCB (Group C) in addition to their baseline medications. Both the systolic blood pressure (SBP) and diastolic blood pressure (DBP) values were significantly decreased at two and 12 months in Group C. In contrast, neither the SBP nor DBP values were significantly changed at two months and eventually decreased at 12 months in Group E. The degree of arterial stiffness, as evaluated according to the cardio-ankle vascular index (CAVI), did not improve at either two or 12 months in Group C, whereas the CAVI values improved as early as at two months and the improvement was sustained at 12 months in Group E. The extent of change in the CAVI was not associated with the level of changes in the SBP or DBP values in Group E.

CONCLUSION

Treatment with eplerenone added to the patient's baseline medications improves the degree of arterial stiffness as early as at two months after the beginning of treatment, independent of the blood pressure-lowering actions of these drugs in patients with uncontrolled hypertension.

Aldosterone up-regulates MMP-9 and MMP-9/NGAL expression in human neutrophils through p38, ERK1/2 and PI3K pathways

Aldosterone and mineralocorticoid receptors are important regulators of inflammation. During this process, chemokines and extracellular matrix degradation by matrix metalloproteases, such as MMP-9, help leukocytes reaching swiftly and infiltrating the injured tissue, two processes essential for tissue repair. Leukocytes, such as neutrophils, are a rich source of MMP-9 and possess mineralocorticoid receptors (MR). The aim of our study was to investigate whether aldosterone was able to regulate proMMP-9, active MMP-9 and MMP-9/NGAL production in human neutrophils. Here we show that aldosterone increased MMP-9 mRNA in a dose- and time-dependent manner. This hormone up-regulated also dose-dependently proMMP-9 and active MMP-9 protein release as well as the MMP-9/NGAL protein complex. PI3K, p38 and ERK1/2 inhibition diminished these aldosterone-induced neutrophil productions. Furthermore, spironolactone, a MR antagonist, counteracted aldosterone-induced increases of proMMP-9, active MMP-9 and MMP-9/NGAL complex. These findings indicate that aldosterone could participate in tissue repair by modulating neutrophil activity and favoring extracellular matrix degradation.

Mineralocorticoid receptor: a critical player in vascular remodeling

Vascular remodeling is a pathological condition with structural changes of blood vessels. Both inside-out and outside-in hypothesis have been put forward to describe mechanisms of vascular remodeling. An integrated model of these two hypotheses emphasizes the importance of immune cells such as monocytes/macrophages, T cells, and dendritic cells. These immune cells are at the center stage to orchestrate cellular proliferation, migration, and interactions of themselves and other vascular cells including endothelial cells (ECs), vascular smooth muscle cells (VSMCs), and fibroblasts. These changes on vascular wall lead to inflammation and oxidative stress that are largely responsible for vascular remodeling. Mineralocorticoid receptor (MR) is a classic nuclear receptor. MR agonist promotes inflammation and oxidative stress and therefore exacerbates vascular remodeling. Conversely, MR antagonists have the opposite effects. MR has direct roles on vascular cells through non-genomic or genomic actions to modulate inflammation and oxidative stress. Recent studies using genetic mouse models have revealed that MR in myeloid cells, VSMCs and ECs all contribute to vascular remodeling. In conclusion, data in the past years have demonstrated that MR is a critical control point in modulating vascular remodeling. Studies will continue to provide evidence with more detailed mechanisms to support this notion.

Eplerenone reduces arterial thrombosis in diabetic rats

INTRODUCTION

Clinical studies demonstrated the benefits of eplerenone (EPL) in reduction of cardiovascular events in diabetic patients. Since acute myocardial infarction (AMI) and stroke are related to acute intravascular thrombosis, we postulate that the beneficial effects of EPL may result from its antithrombotic action.

MATERIALS AND METHODS

Streptozotocin (STZ)-induced diabetic rats were treated with EPL (100 mg/kg/day) for 10 days. Thrombosis in the carotid artery was stimulated electrically.

RESULTS

Thrombosis development was enhanced in STZ-induced diabetic rats as compared to normoglycaemic controls. EPL caused prolongation of the time to artery occlusion, reduction in the incidence of occlusion and decrease in thrombus weight. Changes in the thrombi structure and the inhibition of hypertrophy of the tunica media in the artery wall were also observed. EPL caused reduction in tissue factor, plasminogen activator inhibitor type 1 and interleukin-1β plasma levels.

CONCLUSIONS

Our study demonstrated the antithrombotic effect of EPL manifested by a decrease in the dynamics of thrombus formation and changes in its structure. The changes in thrombosis process were accompanied by antihaemostatic, profibrinolytic and anti-inflammatory effects. The aldosterone blockade with EPL seems to be an additional pharmacological strategy for the prevention and treatment of thrombotic disorders in diabetes.

The cardioprotective effects of mineralocorticoid receptor antagonists

Despite state-of-the-art reperfusion therapy, morbidity and mortality remain significant in patients with an acute myocardial infarction. Therefore, novel strategies to limit myocardial ischemia-reperfusion injury are urgently needed. Mineralocorticoid receptor (MR) antagonists are attractive candidates for this purpose, since several clinical trials in patients with heart failure have reported a survival benefit with MR antagonist treatment. MRs are expressed by several cells of the cardiovascular system, including cardiomyocytes, cardiac fibroblasts, vascular smooth muscle cells, and endothelial cells. Experiments in animal models of myocardial infarction have demonstrated that acute administration of MR antagonists, either before ischemia or immediately at the moment of coronary reperfusion, limits infarct size. This action appears to be independent of the presence of aldosterone and cortisol, which are the endogenous ligands for the MR. The cardioprotective effect is mediated by a nongenomic intracellular signaling pathway, including adenosine receptor stimulation, and activation of several components of the Reperfusion Injury Salvage Kinase (RISK) pathway. In addition to limiting infarct size, MR antagonists can improve scar healing when administered shortly after reperfusion and can reduce cardiac remodeling post myocardial infarction. Clinical trials are currently being performed studying whether early administration of MR antagonists can indeed improve prognosis in patients with an acute myocardial infarction, independent of the presence of heart failure.

The past, present and future of renin-angiotensin aldosterone system inhibition

The renin-angiotensin aldosterone system (RAAS) is central to the pathogenesis of cardiovascular disease. RAAS inhibition can reduce blood pressure, prevent target organ damage in hypertension and diabetes, and improve outcomes in patients with heart failure and/or myocardial infarction. This review presents the history of RAAS inhibition including a summary of key heart failure, myocardial infarction, hypertension and atrial fibrillation trials. Recent developments in RAAS inhibition are discussed including implementation and optimization of current drug therapies. Finally, ongoing clinical trials, opportunities for future trials and issues related to the barriers and approvability of novel RAAS inhibitors are highlighted.

Eplerenone reduced lesion size in early but not advanced atherosclerosis in apolipoprotein E-deficient mice

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.

The role of mineralocorticoid receptor antagonists (MRAs) in very old patients with heart failure

Mineralocorticoid receptor antagonists (MRAs) have been effective in reducing total mortality in patients with heart failure (HF) and a reduced left ventricular ejection fraction. Due to the finding that aldosterone levels decrease with age, one might question the effectiveness of MRAs in very old patients (≥80 years of age), those at the greatest risk for developing HF with a preserved left ventricular ejection fraction (PEF). However, while aldosterone levels decrease with age, there is also a decrease in the enzyme 11 beta HSD2 levels with age, thereby allowing cortisol to stimulate the mineralocorticoid receptor (MR), which in younger patients with higher levels of 11 beta HSD 2 levels is converted to cortisone which cannot activate the MR. There is also an increase in the expression of the MR in the vascular wall with age. Thus, there is reason to believe that MRAs might be effective in reducing cardiovascular mortality and the incidence of hospitalizations for HF in very old patients with HFPEF. There is also reason to believe that MRAs might favorably affect many of the comorbid conditions associated with HFPEF in very old patients. The safety and efficacy of this hypothesis is currently under investigation in the NHLBI sponsored TOPCAT trial.

Aldosterone increases early atherosclerosis and promotes plaque inflammation through a placental growth factor-dependent mechanism

Background

Aldosterone levels correlate with the incidence of myocardial infarction and mortality in cardiovascular patients. Aldosterone promotes atherosclerosis in animal models, but the mechanisms are poorly understood.

Methods and Results

Aldosterone was infused to achieve pathologically relevant levels that did not increase blood pressure in the atherosclerosis‐prone apolipoprotein E–knockout mouse (ApoE−/−). Aldosterone increased atherosclerosis in the aortic root 1.8±0.1‐fold after 4 weeks and in the aortic arch 3.7±0.2‐fold after 8 weeks, without significantly affecting plaque size in the abdominal aorta or traditional cardiac risk factors. Aldosterone treatment increased lipid content of plaques (2.1±0.2‐fold) and inflammatory cell content (2.2±0.3‐fold), induced early T‐cell (2.9±0.3‐fold) and monocyte (2.3±0.3‐fold) infiltration into atherosclerosis‐prone vascular regions, and enhanced systemic inflammation with increased spleen weight (1.52±0.06‐fold) and the circulating cytokine RANTES (regulated and normal T cell secreted; 1.6±0.1‐fold). To explore the mechanism, 7 genes were examined for aldosterone regulation in the ApoE−/− aorta. Further studies focused on the proinflammatory placental growth factor (PlGF), which was released from aldosterone‐treated ApoE−/− vessels. Activation of the mineralocorticoid receptor by aldosterone in human coronary artery smooth muscle cells (SMCs) caused the release of factors that promote monocyte chemotaxis, which was inhibited by blocking monocyte PlGF receptors. Furthermore, PlGF‐deficient ApoE−/− mice were resistant to early aldosterone‐induced increases in plaque burden and inflammation.

Conclusions

Aldosterone increases early atherosclerosis in regions of turbulent blood flow and promotes an inflammatory plaque phenotype that is associated with rupture in humans. The mechanism may involve SMC release of soluble factors that recruit activated leukocytes to the vessel wall via PlGF signaling. These findings identify a novel mechanism and potential treatment target for aldosterone‐induced ischemia in humans.

Aldosterone, atherosclerosis and vascular events in patients with stable coronary artery disease

BACKGROUND AND AIMS

Plasma aldosterone has been associated with all-cause and cardiovascular mortality in high-risk cardiovascular populations, including patients with heart failure, myocardial infarction and high-risk coronary artery disease (CAD) patients. In the present study, we evaluated the association of plasma aldosterone levels with vascular events in a large prospective cohort of stable CAD patients recruited in an outpatient setting. Moreover, we investigated the relationship between aldosterone and atherosclerotic burden.

METHODS AND RESULTS

Baseline plasma aldosterone levels were measured in 2699 subjects with CAD (mean age 60 ± 10 years, 82% male). During a median follow-up of 4.7 years, 308 (11%) patients died, of which 203 were from a vascular cause. Vascular endpoints of myocardial infarction, ischemic stroke or vascular death occurred in 355 (13%) patients. Multivariable Cox regression analysis was performed, adjusting for multiple confounders. Aldosterone (median 96 pg/mL, interquartile range 70-138 pg/mL, normal range 58-362 pg/mL) was independently associated with major vascular events (hazard ratio (HR) 1.56, 95% confidence interval (CI) 1.13-2.15) and vascular mortality (HR 1.95, 95% CI 1.27-3.00). By multivariable regression analysis, aldosterone was also associated with the presence of atherosclerosis in additional vascular territories (cerebrovascular disease and/or peripheral artery disease) (p=0.026).

CONCLUSIONS

In patients with stable coronary artery disease, plasma aldosterone is independently associated with the risk of major vascular events and vascular mortality and with atherosclerotic burden.

Effects of aldosterone on human atherosclerosis: plasma aldosterone and progression of carotid plaque

BACKGROUND

In animal models, aldosterone has adverse cardiac and vascular effects independent of blood pressure, and these are ameliorated by spironolactone or eplerenone (mineralocorticoid receptor antagonists). Both agents reduce mortality in human systolic heart failure. We studied the effect of plasma aldosterone on human carotid atherosclerosis.

METHODS

The effect of plasma aldosterone on progression of carotid total plaque area (TPA) was studied using multiple linear regression, with variables that have previously been shown to maximally explain TPA variation (age, sex, total cholesterol, systolic blood pressure, diabetes, smoking, and medication for cholesterol and systolic blood pressure).

RESULTS

Complete data were available in 848 patients with progression of plaque from baseline to the following year and in 571 for progression in the second year. In stepwise linear regression, plasma aldosterone was the only independent predictor of plaque progression in the first year (P = 0.005) and in the second year (P = 0.001).

CONCLUSIONS

Plasma aldosterone is associated with progression of atherosclerosis. We are now planning to test the effects of mineralocorticoid receptor antagonism on plaque progression.

Therapeutic effect of enhancing endothelial nitric oxide synthase (eNOS) expression and preventing eNOS uncoupling

Nitric oxide (NO) produced by the endothelium is an important protective molecule in the vasculature. It is generated by the enzyme endothelial NO synthase (eNOS). Similar to all NOS isoforms, functional eNOS transfers electrons from nicotinamide adenine dinucleotide phosphate (NADPH), via the flavins flavin adenine dinucleotide and flavin mononucleotide in the carboxy-terminal reductase domain, to the heme in the amino-terminal oxygenase domain. Here, the substrate L-arginine is oxidized to L-citrulline and NO. Cardiovascular risk factors such as diabetes mellitus, hypertension, hypercholesterolaemia or cigarette smoking reduce bioactive NO. These risk factors lead to an enhanced production of reactive oxygen species (ROS) in the vessel wall. NADPH oxidases represent major sources of this ROS and have been found upregulated in the presence of cardiovascular risk factors. NADPH-oxidase-derived superoxide avidly reacts with eNOS-derived NO to form peroxynitrite (ONOO(-)). The essential NOS cofactor (6R-)5,6,7,8-tetrahydrobiopterin (BH(4) ) is highly sensitive to oxidation by this ONOO(-). In BH(4) deficiency, oxygen reduction uncouples from NO synthesis, thereby converting NOS to a superoxide-producing enzyme. Among conventional drugs, compounds interfering with the renin-angiotensin-aldosterone system and statins can reduce vascular oxidative stress and increase bioactive NO. In recent years, we have identified a number of small molecules that have the potential to prevent eNOS uncoupling and, at the same time, enhance eNOS expression. These include the protein kinase C inhibitor midostaurin, the pentacyclic triterpenoids ursolic acid and betulinic acid, the eNOS enhancing compounds AVE9488 and AVE3085, and the polyphenolic phytoalexin trans-resveratrol. Such compounds enhance NO production from eNOS also under pathophysiological conditions and may thus have therapeutic potential.

Mineralocorticoid receptors in vascular function and disease

The mineralocorticoid receptor (MR), a member of the steroid receptor family, regulates blood pressure by mediating the effects of the hormone aldosterone (Aldo) on renal sodium handling. Over the past decade, it has become clear that MR is expressed in the cardiovascular system and interest has grown in understanding the direct role of the MR in regulating vascular function and contributing to cardiovascular disease. This interest stems from multiple clinical studies in which drugs that decrease MR activation also reduce the incidence of heart attacks, strokes, and mortality out of proportion to modest changes in systemic blood pressure. The presence of functional mineralocorticoid receptors in vascular smooth muscle and endothelial cells is now well established and, while still controversial, data supports the vasculature as an Aldo-responsive tissue. This review summarizes recent advances in our understanding of the role of vascular MR in regulating normal vascular function and in promoting vascular disease. In vitro data, in vivo animal studies, and human data are reviewed suggesting a role for MR-activation in promoting vascular oxidative stress, inhibiting vascular relaxation, and contributing to vessel inflammation, fibrosis, and remodeling. These detrimental vascular effects of MR activation appear to be independent of changes in blood pressure and are synergistic with the presence of endothelial dysfunction or damage. Thus, in humans with underlying cardiovascular disease or cardiovascular risk factors, vascular MR activation may promote vascular aging and atherosclerosis thereby contributing to the pathophysiology of heart attack, stroke, and possibly even hypertension. Further exploration of the molecular mechanisms for the detrimental vascular effects of MR activation has the potential to identify novel therapeutic targets to prevent or treat common cardiovascular disorders.

Measuring and targeting aldosterone and renin in atherosclerosis-a review of clinical data

Our understanding of the development and progression of atherosclerosis has increased substantially over the past decades. A significant role for the renin-angiotensin-aldosterone system (RAAS) in this process has gained appreciation in recent years. Preclinical and clinical studies have associated components of the RAAS with various cardiovascular disease conditions. Classically known for its contribution to hypertension, dysregulation of the system is now also believed to promote vascular inflammation, fibrosis, remodeling, and endothelial dysfunction, all intimately related to atherosclerosis. The reduction in cardiovascular mortality and morbidity, as seen with the use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, supports the concept that RAAS is involved in the pathogenesis of atherosclerotic disease. However, the underlying molecular mechanisms of the pathophysiology remain to be completely understood. Evidence points toward additional benefit from therapeutic approaches aiming at more complete inhibition of the system and the possible utility of renin or aldosterone in the prediction of cardiovascular outcome. This review will summarize the current knowledge from clinical studies regarding the presumptive role of renin and aldosterone in the prediction and management of patients with atherosclerosis. For this purpose, a literature search was performed, focusing on available clinical data regarding renin or aldosterone and cardiovascular outcome.

Aldosterone increases VEGF-A production in human neutrophils through PI3K, ERK1/2 and p38 pathways

Aldosterone is now recognised as an important actor in inflammation processes. Neoangiogenesis plays a crucial role in this complex process and immune cells, such as neutrophils, appear to be able to secrete different forms of (pro)angiogenic molecules, especially VEGF-A. The present work was undertaken to investigate whether aldosterone was able to regulate VEGF-A production in human neutrophils. The HL-60 (progranulocytic) cell line and human polymorphonuclear leukocytes were incubated for different time periods with aldosterone. Total cellular RNA extraction, submitted to reverse transcription and real time semi-quantitative PCR, was used to study VEGF-A mRNA expression. Cell supernatants were collected and ELISA tests were performed to analyse VEGF-A protein production. Aldosterone increased VEGF-A mRNA and protein expression in a dose- and time-dependent manner in both cell types. Inhibitors of PI3 kinases, ERK1/2, and to a lesser extent of p38 MAPK, decreased this aldosterone-induced immune cell activation. Western-blot performed with HL-60 cells confirmed that ERK1/2 and p38 MAPK pathways were stimulated by aldosterone. Mineralocorticoid receptors are implicated in this VEGF-A up-regulation because HL-60 cells pre-treated with spironolactone, an aldosterone receptor antagonist, diminished the effects of aldosterone. Aldosterone was also able to increase VEGF-A production of phagocytic cells such as neutrophils. These results suggest that this hormone could play an active role in the neovascularisation process by favouring entry of plasma proteins and fluids into the vascular wall, cell proliferation and tissue rebuilding.

Aldosterone, mortality, and acute ischaemic events in coronary artery disease patients outside the setting of acute myocardial infarction or heart failure

BACKGROUND

Recent studies have demonstrated that aldosterone levels measured in patients with heart failure or acute myocardial infarction (MI) are associated with long-term mortality, but the association with aldosterone levels in patients with coronary artery disease (CAD) outside these specific settings remains unknown. In addition, no clear mechanism has been elucidated to explain these observations. The present study was designed to evaluate the relationship between the level of aldosterone and the risk of death and acute ischaemic events in CAD patients with a preserved left ventricular (LV) function and no acute MI.

METHODS AND RESULTS

In 799 consecutive CAD patients referred for elective coronary angioplasty measurements were obtained before the procedure for: aldosterone (median = 25 pg/mL), brain natriuretic peptide (BNP) (median = 35 pg/mL), hsC-reactive protein (median = 4.17 mg/L), and left ventricular ejection fraction (mean = 58%). Patients with acute MI or coronary syndrome (ACS) who required urgent revascularization were not included in the study. The primary endpoint, cardiovascular death, occurred in 41 patients during a median follow-up period of 14.9 months. Secondary endpoints-total mortality, acute ischaemic events (acute MI or ischaemic stroke), and the composite of death and acute ischaemic events-were observed in 52, 54, and 94 patients, respectively. Plasma aldosterone was found to be related to BMI, hypertension and NYHA class, and inversely related to age, creatinine clearance, and use of beta-blockers. Multivariate Cox model analysis demonstrated that aldosterone was independently associated with cardiovascular mortality (P = 0.001), total mortality (P = 0.001), acute ischaemic events (P = 0.01), and the composite of death and acute ischaemic events (P = 0.004). Reclassification analysis, using integrated discrimination improvement (IDI) and net reclassification improvement (NRI), demonstrated incremental predictive value of aldosterone (P < 0.0001).

CONCLUSION

Our results demonstrate that, in patients with CAD but without heart failure or acute MI, the level of aldosterone is strongly and independently associated with mortality and the occurrence of acute ischaemic events.

11β-hydroxysteroid dehydrogenase type 2 deficiency accelerates atherogenesis and causes proinflammatory changes in the endothelium in apoe-/- mice

Mineralocorticoid receptor (MR) activation is proinflammatory and proatherogenic. Antagonism of MR improves survival in humans with congestive heart failure caused by atherosclerotic disease. In animal models, activation of MR exacerbates atherosclerosis. The enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) prevents inappropriate activation of the MR by inactivating glucocorticoids in mineralocorticoid-target tissues. To determine whether glucocorticoid-mediated activation of MR increases atheromatous plaque formation, we generated Apoe(-/-)/11β-HSD2(-/-) double-knockout (E/b2) mice. On chow diet, E/b2 mice developed atherosclerotic lesions by 3 months of age, whereas Apolipoprotein E (Apoe(-/-)) mice remained lesion free. Brachiocephalic plaques in 3-month-old E/b2 mice showed increased macrophage and lipid content and reduced collagen content compared with similar sized brachiocephalic plaques in 6-month-old Apoe(-/-) mice. Crucially, treatment of E/b2 mice with eplerenone, an MR antagonist, reduced plaque development and macrophage infiltration while increasing collagen and smooth muscle cell content without any effect on systolic blood pressure. In contrast, reduction of systolic blood pressure in E/b2 mice using the epithelial sodium channel blocker amiloride produced a less-profound atheroprotective effect. Vascular cell adhesion molecule 1 expression was increased in the endothelium of E/b2 mice compared with Apoe(-/-) mice. Similarly, aldosterone increased vascular cell adhesion molecule 1 expression in mouse aortic endothelial cells, an effect mimicked by corticosterone only in the presence of an 11β-HSD2 inhibitor. Thus, loss of 11β-HSD2 leads to striking atherogenesis associated with activation of MR, stimulating proinflammatory processes in the endothelium of E/b2 mice.

Review article: eplerenone: an underused medication?

In this article, we review the evidence supporting the use of eplerenone for improving cardiovascular prognosis. Activation of the renin-angiotensin-aldosterone system plays a major role in the pathogenesis of heart disease, and blockage of this system has been shown to improve prognosis in several cardiovascular conditions. The 2 marketed aldosterone antagonists, spironolactone and eplerenone, improve prognosis in patients with left ventricular (LV) dysfunction and are effective antihypertensive medications. In addition, a potential role for aldosterone antagonists in the treatment of patients with heart failure and preserved LV function has been suggested and is currently being evaluated in clinical trials. In patients with myocardial infarction having LV dysfunction and evidence of heart failure, eplerenone improves cardiovascular outcomes and attenuates myocardial remodeling. In addition, eplerenone is effective for the treatment of hypertension, where it regresses both LV hypertrophy and proteinuria (2 powerful markers of increased cardiovascular risk). In contrast to spironolactone, eplerenone essentially lacks the sexual side effects that sometimes limit the use of spironolactone. Hyperkalemia is the main potential side effect of eplerenone, especially when used in combination with other medications that can cause hyperkalemia. Adequate patient selection and monitoring are therefore of utmost importance when using this medication. In conclusion, eplerenone is a medication that offers the cardiovascular therapeutic and prognostic benefits of aldosterone antagonism but with fewer side effects compared to spironolactone.

A role of the bile salt receptor FXR in atherosclerosis

This study reviews current insights into the role of bile salts and bile salt receptors on the progression and regression of atherosclerosis. Bile salts have emerged as important modifiers of lipid and energy metabolism. At the molecular level, bile salts regulate lipid and energy homeostasis mainly via the bile salt receptors FXR and TGR5. Activation of FXR has been shown to improve plasma lipid profiles, whereas Fxr(-/-) mice have increased plasma triglyceride and very-low-density lipoprotein levels. Nevertheless, high-density lipoprotein cholesterol levels are increased in these mice, suggesting that FXR has both anti- and proatherosclerotic properties. Interestingly, there is increasing evidence for a role of FXR in "nonclassical" bile salt target tissues, eg, vasculature and macrophages. In these tissues, FXR has been shown to influence vascular tension and regulate the unloading of cholesterol from foam cells, respectively. Recent publications have provided insight into the antiinflammatory properties of FXR in atherosclerosis. Bile salt signaling via TGR5 might regulate energy homeostasis, which could serve as an attractive target to increase energy expenditure and weight loss. Interventions aiming to increase cholesterol turnover (eg, by bile salt sequestration) significantly improve plasma lipid profiles and diminish atherosclerosis in animal models. Bile salt metabolism and bile salt signaling pathways represent attractive therapeutic targets for the treatment of atherosclerosis.

Impact of medical therapy on atheroma volume measured by different cardiovascular imaging modalities

Atherosclerosis is a systemic disease that affects most vascular beds. The gold standard of atherosclerosis imaging has been invasive intravascular ultrasound (IVUS). Newer noninvasive imaging modalities like B-mode ultrasound, cardiac computed tomography (CT), positron emission tomography (PET), and magnetic resonance imaging (MRI) have been used to assess these vascular territories with high accuracy and reproducibility. These imaging modalities have lately been used for the assessment of the atherosclerotic plaque and the response of its volume to several medical therapies used in the treatment of patients with cardiovascular disease. To study the impact of these medications on atheroma volume progression or regression, imaging modalities have been used on a serial basis providing a unique opportunity to monitor the effect these antiatherosclerotic strategies exert on plaque burden. As a result, studies incorporating serial IVUS imaging, quantitative coronary angiography (QCA), B-mode ultrasound, electron beam computed tomography (EBCT), and dynamic contrast-enhanced magnetic resonance imaging have all been used to evaluate the impact of therapeutic strategies that modify cholesterol and blood pressure on the progression/regression of atherosclerotic plaque. In this review, we intend to summarize the impact of different therapies aimed at halting the progression or even result in regression of atherosclerotic cardiovascular disease evaluated by different imaging modalities.

Aldosterone and mineralocorticoid receptors in the cardiovascular system

Aldosterone is currently thought to exert its physiologic effects by activating epithelial mineralocorticoid receptors, and its pathologic effects on the cardiovascular system via mineralocorticoid receptors in the heart and blood vessels. Recent studies have extended this understanding to include a reevaluation of the roles of aldosterone and mineralocorticoid receptor activation in blood pressure control; the rapid, nongenomic effects of aldosterone; the role of cortisol as a mineralocorticoid receptor agonist under conditions of redox change/tissue damage/reactive oxygen species generation; the growing consensus that primary aldosteronism accounts for approximately 10% of all essential hypertension; recent new insights into the cardioprotective role of spironolactone; and the development of third- and fourth-generation mineralocorticoid receptor antagonists for use in cardiovascular and other inflammatory disease. These findings on aldosterone action and mineralocorticoid receptor blockade are analyzed in the context of the prevention and treatment of cardiovascular disease.

Aldosterone and the cardiovascular system: a dangerous association

Initial studies have focussed on the actions of aldosterone in renal electrolyte handling and, as a consequence, blood pressure control. More recently, attention has primarily been focussed on its actions on the heart and vascular system, where it is locally produced. Aldosterone by binding mineralocorticoid receptors causes oxidative stress, fibrosis and triggers an inflammatory response in the cardiovascular system. All these effects could be underlying the role of aldo-sterone on cardiac and vascular remodelling associated with different pathological situations. At the vascular level, aldo-sterone affects endothelial function because administration of aldosterone to rats impaired endothelium-dependent relaxations. In addition, the administration of mineralocorticoid receptor antagonists ameliorates endothelium-dependent relaxation in models of both hypertension and atherosclerosis, and in patients with heart failure. Several mechanisms can participate in this effect, including production of vasoconstrictor factors and a reduction in nitric oxide levels. This reduction can involve both a decrease in its production as well as an increase in its degradation by reactive oxygen species. Aldosterone can produce oxidative stress by the activation of transcription factors such as the NF-κB system, which can also trigger an inflammatory process through the production of different cytokines. At cardiac level, high levels of aldosterone can also adversely impact heart function by producing cardiac hypertrophy, diastolic dysfunction and electrical remodelling through changes in ionic channels. All these effects can explain the beneficial effect of mineralocorticoid blockade in the cardiovascular system.

Aldosterone: a forgotten mediator of the relationship between psychological stress and heart disease

Numerous studies support the notion that cumulative exposure to chronic stress is a risk factor for cardiovascular disease (CVD). Various stress-related hormones have been proposed as potential mediators of the relationship between psychological stress and CVD, including catecholamines and more indirectly, cortisol. Somewhat surprisingly, although aldosterone is also released in response to hypothalamic-pituitary-adrenal (HPA) axis activation, it has not been considered as relevant for this relationship. In the present review we will consider aldosterone as a potentially important mediator of the relationship between negative affective states and CVD. First, we will briefly review the known functions and roles of aldosterone, and then consider its actions in both the brain and the periphery. We will then review the available literature on the role of aldosterone in CVD, and also consider links between aldosterone and various forms of chronic psychological stress. Finally we will present an integrated model of how aldosterone may mediate effects of chronic stress on CVD, recommend new directions for research, and identify important methodological and design issues for this work.

Effect of canrenone and amiloride on the prooxidative effect induced by aldosterone in human mononuclear leukocytes in vitro

Clinical studies have demonstrated that aldosterone receptor antagonists do improve the survival of patients with chronic heart diseases and in vitro studies have shown that canrenone blocks the proinflammatory effect of aldosterone in mononucler leukocytes (MNL). The aim of the study was to compare, in the model of human MNL, the effect of potassium-sparing diuretics amiloride and canrenone, on the protein expression of p22phox, a NADPH-oxidase system subunit, that is a principal marker of production of superoxide anions. MNL were isolated from 10 informed healthy volunteers (5 males and 5 females, age range 24-36 yr) and the proteins extracted. p22phox protein expression was evaluated by Western blot and quantified using a densitometric semiquantitative analysis. The experiments showed that aldosterone (10(-8) M) enhances the protein expression of p22phox and that its effect is reversed by co-incubation with canrenone (10(-6) M), while incubation with amiloride (10(-6) M) reduced the prooxidative effect of aldosterone at a significantly lower extent than canrenone. Co-incubation with canrenone, amiloride, and aldosterone together produced the same effect as aldosterone plus canrenone. Incubation with cortisol (40(-8) M) was not effective. These data confirm the prooxidative effect of aldosterone in MNL. The addition of aldosterone-receptor antagonist canrenone produced a higher inhibition than sodium channel blocker amiloride on the effect of aldosterone on p22phox protein expression.

Nitric oxide, NAD(P)H oxidase, and atherosclerosis

The endothelial cell layer plays a major role in the development and progression of atherosclerosis. Endothelial NO synthase (eNOS) produces nitric oxide (NO) from L-arginine. NO can rapidly react with reactive oxygen species to form peroxynitrite. This reduces NO availability, impairs vasodilatation, and mediates proinflammatory and prothrombotic processes such as leukocyte adhesion and platelet aggregation. In the vessel wall, specific NAD(P)H oxidase complexes are major sources of reactive oxygen species. These NAD(P)H oxidases can transfer electrons across membranes to oxygen and generate superoxide anions. The short-lived superoxide anion rapidly dismutates to hydrogen peroxide, which can further increase the production of reactive oxygen species. This can lead to uncoupling of eNOS switching enzymatic activity from NO to superoxide production. This review describes the structure and regulation of different NAD(P)H oxidase complexes. We will also focus on NO/superoxide anion balance as modulated by hemodynamic forces, vasoconstrictors, and oxidized low-density lipoprotein. We will then summarize the recent advances defining the role of nitric oxide and NAD(P)H oxidase-derived reactive oxygen species in the development and progression of atherosclerosis. In conclusion, novel mechanisms affecting the vascular NO/superoxide anion balance will allow the development of therapeutic strategies in the treatment of cardiovascular diseases.